Mitchell B Cohen

All Publications

• Risk Categorization Predicts Disability in Pain-associated Functional Gastrointestinal Disorders After 6 Months JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Cunningham, N. R., Jagpal, A., Peugh, J., Farrell, M. K., Cohen, M. B., Mezoff, A. G., Lynch-Jordan, A., Kashikar-Zuck, S. 2017; 64 (5): 685-690

  Abstract

  For a large portion of youth, pain-associated functional gastrointestinal disorders (FGIDs) are associated with significant impairment over time. Clinically feasible methods to categorize youth with FGIDs at greatest risk for persistent pain-related impairment have not yet been identified.Measures of functional disability, pain intensity, and anxiety were collected on 99 patients with FGIDs (ages 8-18) during a visit to a pediatric gastroenterology office to assess for the presence of risk. Follow-up data were obtained on a subset of this sample (n = 64) after 6 months, either in person or via mail. The present study examined whether a greater number of risk factors at baseline predicted greater pain-related disability at follow-up.Patients were divided into 4 groups based on number of risk factors present at the initial assessment: 0 (18.2%), 1 (24.2%), 2 (26.3%), and 3 (31.3%). The presence of 2 or 3 risk factors significantly predicted greater disability at follow-up compared to those with 0 risk factors (R = 0.311) and those with just 1 risk factor (Cohen's d values of -1.07 and -1.44, respectively).A simple approach to risk categorization can identify youth with FGIDs who are most likely to report increased levels of pain-related impairment over time. These findings have important clinical implications that support the utility of a brief screening process during medical care to inform referral for targeted treatment approaches to FGIDs.

  View details for DOI 10.1097/MPG.0000000000001342

  View details for Web of Science ID 000402071000014

  View details for PubMedID 27437930

  View details for PubMedCentralID PMC5250593

• Update on Diarrhea PEDIATRICS IN REVIEW CaJacob, N. J., Cohen, M. B. 2016; 37 (8): 313-322

  View details for DOI 10.1542/pir.2015-0099

  View details for Web of Science ID 000382483100002

  View details for PubMedID 27482061

• Comparison of Recommendations in Clinical Practice Guidelines for Acute Gastroenteritis in Children JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Lo Vecchio, A., Dias, J., Berkley, J. A., Boey, C., Cohen, M. B., Cruchet, S., Liguoro, I., Salazar Lindo, E., Sandhu, B., Sherman, P., Shimizu, T., Guarino, A. 2016; 63 (2): 226-235

  Abstract

  Acute gastroenteritis (AGE) is a major cause of child mortality and morbidity. This study aimed at systematically reviewing clinical practice guidelines (CPGs) on AGE to compare recommendations and provide the basis for developing single universal guidelines.CPGs were identified by searching MEDLINE, Cochrane-Library, National Guideline Clearinghouse and Web sites of relevant societies/organizations producing and/or endorsing CPGs.The definition of AGE varies among the 15 CPGs identified. The parameters most frequently recommended to assess dehydration are skin turgor and sunken eyes (11/15, 73.3%), general appearance (11/15, 66.6%), capillary refill time, and mucous membranes appearance (9/15, 60%). Oral rehydration solution is universally recognized as first-line treatment. The majority of CPGs recommend hypo-osmolar (Na 45-60 mmol/L, 11/15, 66.6 %) or low-osmolality (Na 75 mmol/L, 9/15, 60%) solutions. In children who fail oral rehydration, most CPGs suggest intravenous rehydration (66.6%). However, nasogastric tube insertion for fluid administration is preferred according by 5/15 CPGs (33.3%). Changes in diet and withdrawal of food are discouraged by all CPGs, and early refeeding is strongly recommended in 13 of 15 (86.7%). Zinc is recommended as an adjunct to ORS by 10 of 15 (66.6%) CPGs, most of them from low-income countries. Probiotics are considered by 9 of 15 (60%) CPGs, 5 from high-income countries. Antiemetics are not recommended in 9 of 15 (60%) CPGs. Routine use of antibiotics is discouraged.Key recommendations for the management of AGE in children are similar in CPGs. Together with accurate review of evidence-base this may represent a starting point for developing universal recommendations for the management of children with AGE worldwide.

  View details for DOI 10.1097/MPG.0000000000001133

  View details for Web of Science ID 000380943800016

  View details for PubMedID 26835905

  View details for PubMedCentralID PMC6858859

• Single-dose Live Oral Cholera Vaccine CVD 103-HgR Protects Against Human Experimental Infection With <i>Vibrio cholerae</i> O1 El Tor CLINICAL INFECTIOUS DISEASES Chen, W. H., Cohen, M. B., Kirkpatrick, B. D., Brady, R. C., Galloway, D., Gurwith, M., Hall, R. H., Kessler, R. A., Lock, M., Haney, D., Lyon, C. E., Pasetti, M. F., Simon, J. K., Szabo, F., Tennant, S., Levine, M. M. 2016; 62 (11): 1329-1335

  Abstract

  No licensed cholera vaccine is presently available in the United States. Cholera vaccines available in other countries require 2 spaced doses. A single-dose cholera vaccine that can rapidly protect short-notice travelers to high-risk areas and help control explosive outbreaks where logistics render 2-dose immunization regimens impractical would be a major advance.PXVX0200, based on live attenuated Vibrio cholerae O1 classical Inaba vaccine strain CVD 103-HgR, elicits seroconversion of vibriocidal antibodies (a correlate of protection) within 10 days of a single oral dose. We investigated the protection conferred by this vaccine in a human cholera challenge model.Consenting healthy adult volunteers, 18-45 years old, were randomly allocated 1:1 to receive 1 oral dose of vaccine (approximately 5 × 10(8) colony-forming units [CFU]) or placebo in double-blind fashion. Volunteers ingested approximately 1 × 10(5) CFU of wild-type V. cholerae O1 El Tor Inaba strain N16961 10 days or 3 months after vaccination and were observed on an inpatient research ward for stool output measurement and management of hydration.The vaccine was well tolerated, with no difference in adverse event frequency among 95 vaccinees vs 102 placebo recipients. The primary endpoint, moderate (≥3.0 L) to severe (≥5.0 L) diarrheal purge, occurred in 39 of 66 (59.1%) placebo controls but only 2 of 35 (5.7%) vaccinees at 10 days (vaccine efficacy, 90.3%; P < .0001) and 4 of 33 (12.1%) vaccinees at 3 months (vaccine efficacy, 79.5%; P < .0001).The significant vaccine efficacy documented 10 days and 3 months after 1 oral dose of PXVX0200 supports further development as a single-dose cholera vaccine.NCT01895855.

  View details for DOI 10.1093/cid/ciw145

  View details for Web of Science ID 000378433400006

  View details for PubMedID 27001804

  View details for PubMedCentralID PMC4872293

• Current Issues in Transitioning from Pediatric to Adult-Based Care for Youth with Chronic Health Care Needs JOURNAL OF PEDIATRICS Hergenroeder, A. C., Wiemann, C. M., Cohen, M. B. 2015; 167 (6): 1196-1201

  Abstract

  For over 25 years, with medical advances increasing the lifespan of YYASHCN, we have been aware of the need to improve health care transition to adult-based care services. Barriers to health care transition have been identified and in a number of settings, recognition of the problem and preliminary success has been achieved for pilot programs. Evidence-based solutions to improve health care transition for YYASHCN are needed. There are barriers at the patient, family, pediatric, and adult provider, and insurance system levels that must be overcome.

  View details for DOI 10.1016/j.jpeds.2015.08.005

  View details for Web of Science ID 000366143900008

  View details for PubMedID 26340879

• Concordant Parent-Child Reports of Anxiety Predict Impairment in Youth With Functional Abdominal Pain JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Cunningham, N. R., Cohen, M. B., Farrell, M. K., Mezoff, A. G., Lynch-Jordan, A., Kashikar-Zuck, S. 2015; 60 (3): 312-317

  Abstract

  Functional abdominal pain (FAP) is associated with significant anxiety and impairment. Prior investigations of child anxiety in youth with FAP are generally limited by small sample sizes, based on child report, and use lengthy diagnostic tools. It is unknown whether a brief anxiety-screening tool is feasible, whether parent and child reports of anxiety are congruent, and whether parent and child agreement of child anxiety corresponds to increased impairment. The purpose of this investigation was to examine anxiety characteristics in youth with FAP using parent and child reports. Parent-child agreement of child anxiety symptoms was examined in relation to pain and disability.One hundred patients with FAP (8-18 years of age) recruited from pediatric gastroenterology clinics completed measures of pain intensity (Numeric Rating Scale) and disability (Functional Disability Inventory). Patients and caregivers both completed a measure of child anxiety characteristics (Screen for Child Anxiety and Related Disorders).Clinically significant anxiety symptoms were more commonly reported by youth (54%) than their parents (30%). Panic/somatic symptoms, generalized anxiety, and separation anxiety were most commonly endorsed by patients, whereas generalized anxiety, separation anxiety, and school avoidance were most commonly reported by parents. The majority (65%) of parents and children agreed on the presence (26%) or absence (39%) of clinically significant anxiety. Parent-child agreement of clinically significant anxiety was related to increased impairment.A brief screening instrument of parent and child reports of anxiety can provide clinically relevant information for comprehensive treatment planning in children with FAP.

  View details for DOI 10.1097/MPG.0000000000000625

  View details for Web of Science ID 000350527100010

  View details for PubMedID 25714575

  View details for PubMedCentralID PMC4341941

• CNS, lung, and lymph node involvement in Gaucher disease type 3 after 11 years of therapy: Clinical, histopathologic, and biochemical findings MOLECULAR GENETICS AND METABOLISM Burrow, T. A., Sun, Y., Prada, C. E., Bailey, L., Zhang, W., Brewer, A., Wu, S. W., Setchell, K. R., Witte, D., Cohen, M. B., Grabowski, G. A. 2015; 114 (2): 233-241

  Abstract

  A Caucasian male with Gaucher disease type 3, treated with continuous enzyme therapy (ET) for 11 years, experienced progressive mesenteric and retroperitoneal lymphadenopathy, lung disease, and neurological involvement leading to death at an age of 12.5 years. Autopsy showed significant pathology of the brain, lymph nodes, and lungs. Liver and spleen glucosylceramide (GluCer) and glucosylsphingosine (GluS) levels were nearly normal and storage cells were cleared. Clusters of macrophages and very elevated GluCer and GluS levels were in the lungs, and brain parenchymal and perivascular regions. Compared to normal brain GluCer (GC 18:0), GluCer species with long fatty acid acyl chains were increased in the patient's brain. This profile was similar to that in the patient's lungs, suggesting that these lipids were present in brain perivascular macrophages. In the patient's brain, generalized astrogliosis, and enhanced LC3, ubiquitin, and Tau signals were identified in the regions surrounding macrophage clusters, indicating proinflammation, altered autophagy, and neurodegeneration. These findings highlight the altered phenotypes resulting from increased longevity due to ET, as well as those in poorly accessible compartments of brain and lung, which manifested progressive disease involvement despite ET.

  View details for DOI 10.1016/j.ymgme.2014.08.011

  View details for Web of Science ID 000348973100311

  View details for PubMedID 25219293

  View details for PubMedCentralID PMC4312736

• Effect of Guanylate Cyclase-C Activity on Energy and Glucose Homeostasis DIABETES Begg, D. P., Steinbrecher, K. A., Mul, J. D., Chambers, A. P., Kohli, R., Haller, A., Cohen, M. B., Woods, S. C., Seeley, R. J. 2014; 63 (11): 3798-3804

  Abstract

  Uroguanylin is a gastrointestinal hormone primarily involved in fluid and electrolyte handling. It has recently been reported that prouroguanylin, secreted postprandially, is converted to uroguanylin in the brain and activates the receptor guanylate cyclase-C (GC-C) to reduce food intake and prevent obesity. We tested central nervous system administration of two GC-C agonists and found no significant reduction of food intake. We also carefully phenotyped mice lacking the GC-C receptor and found them to have normal body weight, adiposity, and glucose tolerance. Interestingly, uroguanylin knockout mice had a small but significant increase in body weight and adiposity that was accompanied by glucose intolerance. Our data indicate that the modest effects of uroguanylin on energy and glucose homeostasis are not mediated by central GC-C receptors.

  View details for DOI 10.2337/db14-0160

  View details for Web of Science ID 000343966100028

  View details for PubMedID 24898144

  View details for PubMedCentralID PMC4207398

• Acid-Reducing Agents in Infants and Children Friend or Foe? JAMA PEDIATRICS Menchise, A. N., Cohen, M. B. 2014; 168 (10): 888-890

  View details for DOI 10.1001/jamapediatrics.2014.1263

  View details for Web of Science ID 000344699800011

  View details for PubMedID 25133653

• Role of Celiac Disease Screening for Children With Functional Gastrointestinal Disorders JAMA PEDIATRICS Squires, J. E., Fei, L., Cohen, M. B. 2014; 168 (6): 514-515

  View details for DOI 10.1001/jamapediatrics.2013.5418

  View details for Web of Science ID 000336840800007

  View details for PubMedID 24756772

• Safety and Immunogenicity of a Single Oral Dose of Recombinant Double Mutant Heat-Labile Toxin Derived from Enterotoxigenic (vol 20, pg 1764, 2013) CLINICAL AND VACCINE IMMUNOLOGY El-Kamary, S. S., Cohen, M. B., Bourgeois, A., Van De Verg, L., Bauers, N., Reymann, M., Pasetti, M. F., Chen, W. H. 2014; 21 (4): 602

  View details for DOI 10.1128/CVI.00075-14

  View details for Web of Science ID 000333678500020

• Fecal microbiota transplantation for <i>Clostridium difficile</i> infection: benefits and barriers CURRENT OPINION IN GASTROENTEROLOGY Lo Vecchio, A., Cohen, M. B. 2014; 30 (1): 47-53

  Abstract

  The incidence and severity of Clostridium difficile infection (CDI) have increased worldwide in the past two decades. A principal function of the gut microbiota is to protect the intestine against colonization by exogenous pathogens. Increasingly, the gut microbiota have been shown to influence susceptibility to other genetic and environmentally acquired conditions. Transplantation of healthy donor fecal material in patients with CDI may re-establish the normal composition of the gut microbiota and has been shown to be effective in recurrent CDI. We intend to review the most recent data on fecal microbiota transplantation (FMT) and critically discuss potential advantages and handicaps of this new therapeutic approach.Evidence from case series and only one randomized clinical trial suggests that FMT is able to restore the wide diversity of microflora, improve C. difficile-related symptoms and prevent CDI recurrence.FMT is a promising treatment option for serious and recurrent CDI, and current evidence (although weak) demonstrates consistent and excellent efficacy in clinical outcomes. However, many questions should be answered before it may be recommended as routine standard treatment. Mechanisms of action need to be better understood. Long-term follow-up studies are needed to determine long-lasting effects (including the association with autoimmune diseases).

  View details for DOI 10.1097/MOG.0000000000000023

  View details for Web of Science ID 000328575500007

  View details for PubMedID 24275671

• Linaclotide Inhibits Colonic Nociceptors and Relieves Abdominal Pain via Guanylate Cyclase-C and Extracellular Cyclic Guanosine 3′,5′-Monophosphate GASTROENTEROLOGY Castro, J., Harrington, A. M., Hughes, P. A., Martin, C. M., Ge, P., Shea, C. M., Jin, H., Jacobson, S., Hannig, G., Mann, E., Cohen, M. B., MacDougall, J. E., Lavins, B. J., Kurtz, C. B., Silos-Santiago, I., Johnston, J. M., Currie, M. G., Blackshaw, L., Brierley, S. M. 2013; 145 (6): 1334-+

  Abstract

  Linaclotide is a minimally absorbed agonist of guanylate cyclase-C (GUCY2C or GC-C) that reduces symptoms associated with irritable bowel syndrome with constipation (IBS-C). Little is known about the mechanism by which linaclotide reduces abdominal pain in patients with IBS-C.We determined the effects of linaclotide on colonic sensory afferents in healthy mice and those with chronic visceral hypersensitivity. We assessed pain transmission by measuring activation of dorsal horn neurons in the spinal cord in response to noxious colorectal distention. Levels of Gucy2c messenger RNA were measured in tissues from mice using quantitative reverse transcription polymerase chain reaction and in situ hybridization. We used human intestinal cell lines to measure release of cyclic guanosine-3',5'-monophosphate (cGMP) by linaclotide. We performed a post-hoc analysis of data from a phase III, double-blind, parallel-group study in which 805 patients with IBS-C were randomly assigned to groups given an oral placebo or 290 μg linaclotide once daily for 26 weeks. We quantified changes in IBS-C symptoms, including abdominal pain.In mice, linaclotide inhibited colonic nociceptors with greater efficacy during chronic visceral hypersensitivity. Intra-colonic administration of linaclotide reduced signaling of noxious colorectal distention to the spinal cord. The colonic mucosa, but not neurons, was found to express linaclotide's target, GC-C. The downstream effector of GC-C, cGMP, was released after administration of linaclotide and also inhibited nociceptors. The effects of linaclotide were lost in Gucy2c(-/-) mice and prevented by inhibiting cGMP transporters or removing the mucosa. During 26 weeks of linaclotide administration, a significantly greater percentage of patients (70%) had at least a 30% reduction in abdominal pain compared with patients given placebo (50%).We have identified an analgesic mechanism of linaclotide: it activates GC-C expressed on mucosal epithelial cells, resulting in the production and release of cGMP. This extracellular cGMP acts on and inhibits nociceptors, thereby reducing nociception. We also found that linaclotide reduces chronic abdominal pain in patients with IBS-C.

  View details for DOI 10.1053/j.gastro.2013.08.017

  View details for Web of Science ID 000327537600036

  View details for PubMedID 23958540

• Guanylate Cyclase C Deficiency Causes Severe Inflammation in a Murine Model of Spontaneous Colitis PLOS ONE Harmel-Laws, E., Mann, E. A., Cohen, M. B., Steinbrecher, K. A. 2013; 8 (11): e79180

  Abstract

  Guanylate Cyclase C (GC-C; Gucy2c) is a transmembrane receptor expressed in intestinal epithelial cells. Activation of GC-C by its secreted ligand guanylin stimulates intestinal fluid secretion. Familial mutations in GC-C cause chronic diarrheal disease or constipation and are associated with intestinal inflammation and infection. Here, we investigated the impact of GC-C activity on mucosal immune responses.We utilized intraperitoneal injection of lipopolysaccharide to elicit a systemic cytokine challenge and then measured pro-inflammatory gene expression in colonic mucosa. GC-C(+/+) and GC-C(-/-) mice were bred with interleukin (IL)-10 deficient animals and colonic inflammation were assessed. Immune cell influx and cytokine/chemokine expression was measured in the colon of wildtype, IL-10(-/-), GC-C(+/+)IL-10(-/-) and GC-C(-/-)IL-10(-/-) mice. GC-C and guanylin production were examined in the colon of these animals and in a cytokine-treated colon epithelial cell line.Relative to GC-C(+/+) animals, intraperitoneal lipopolysaccharide injection into GC-C(-/-) mice increased proinflammatory gene expression in both whole colon tissue and in partially purified colonocyte isolations. Spontaneous colitis in GC-C(-/-)IL-10(-/-) animals was significantly more severe relative to GC-C(+/+)IL-10(-/-) mice. Unlike GC-C(+/+)IL-10(-/-) controls, colon pathology in GC-C(-/-)IL-10(-/-) animals was apparent at an early age and was characterized by severely altered mucosal architecture, crypt abscesses, and hyperplastic subepithelial lesions. F4/80 and myeloperoxidase positive cells as well as proinflammatory gene expression were elevated in GC-C(-/-)IL-10(-/-) mucosa relative to control animals. Guanylin was diminished early in colitis in vivo and tumor necrosis factor α suppressed guanylin mRNA and protein in intestinal goblet cell-like HT29-18-N2 cells.The GC-C signaling pathway blunts colonic mucosal inflammation that is initiated by systemic cytokine burst or loss of mucosal immune cell immunosuppression. These data as well as the apparent intestinal inflammation in human GC-C mutant kindred underscore the importance of GC-C in regulating the response to injury and inflammation within the gut.

  View details for DOI 10.1371/journal.pone.0079180

  View details for Web of Science ID 000327221600115

  View details for PubMedID 24244444

  View details for PubMedCentralID PMC3823613

• Safety and Immunogenicity of a Single Oral Dose of Recombinant Double Mutant Heat-Labile Toxin Derived from Enterotoxigenic <i>Escherichia coli</i> CLINICAL AND VACCINE IMMUNOLOGY El-Kamary, S. S., Cohen, M. B., Bourgeois, A., Van De Verg, L., Bauers, N., Reymann, M., Pasetti, M. F., Chen, W. H. 2013; 20 (11): 1764-1770

  Abstract

  Enterotoxigenic Escherichia coli (ETEC) is a primary cause of traveler's diarrhea for which there is no licensed vaccine. This phase 1 trial determined the safety and immunogenicity of a recombinantly produced double mutant heat-labile enterotoxin (dmLT) of ETEC. It was administered as a single oral dose of dmLT in escalating doses of 5 μg, 25 μg, 50 μg, and 100 μg, followed by a 72-h inpatient observation, outpatient visits at 8, 14, and 28 days, and telephone calls at 2 and 6 months postvaccination. Safety was assessed by frequency of adverse events, and immune responses determined after immunization included dmLT-specific serum IgA and IgG, fecal IgA, antibody-secreting cells (ASC), and antibodies in lymphocyte supernatant (ALS) responses. All doses were well tolerated by the 36 healthy adults enrolled. Immune responses were limited in the 5- and 25-μg dose recipients. The 50-μg dose recipients trended toward stronger responses than the 100-μg dose recipients by serum IgA (67% versus 33%, P = 0.22), serum IgG (58% versus 33%, P = 0.41), and fecal IgA (58% versus 33%, P = 0.41). By day 14 postvaccination, there were significantly more positive responders (≥4-fold increase from baseline) among the 50- versus 100-μg dose recipients for serum IgA (P = 0.036) but not serum IgG (P = 0.21). In conclusion, a single oral dose of dmLT was well tolerated and immunogenic, with immune responses plateauing at the 50-μg dose. (This clinical trial is registered at www.clinicaltrials.gov, registration number NCT01147445.).

  View details for DOI 10.1128/CVI.00464-13

  View details for Web of Science ID 000326165300015

  View details for PubMedID 24049109

  View details for PubMedCentralID PMC3837789

• Guanylate cyclase C limits systemic dissemination of a murine enteric pathogen BMC GASTROENTEROLOGY Mann, E. A., Harmel-Laws, E., Cohen, M. B., Steinbrecher, K. A. 2013; 13: 135

  Abstract

  Guanylate Cyclase C (GC-C) is an apically-oriented transmembrane receptor that is expressed on epithelial cells of the intestine. Activation of GC-C by the endogenous ligands guanylin or uroguanylin elevates intracellular cGMP and is implicated in intestinal ion secretion, cell proliferation, apoptosis, intestinal barrier function, as well as the susceptibility of the intestine to inflammation. Our aim was to determine if GC-C is required for host defense during infection by the murine enteric pathogen Citrobacter rodentium of the family Enterobacteriacea.GC-C+/+ control mice or those having GC-C genetically ablated (GC-C-/-) were administered C. rodentium by orogastric gavage and analyzed at multiple time points up to post-infection day 20. Commensal bacteria were characterized in uninfected GC-C+/+ and GC-C-/- mice using 16S rRNA PCR analysis.GC-C-/- mice had an increase in C. rodentium bacterial load in stool relative to GC-C+/+. C. rodentium infection strongly decreased guanylin expression in GC-C+/+ mice and, to an even greater degree, in GC-C-/- animals. Fluorescent tracer studies indicated that mice lacking GC-C, unlike GC-C+/+ animals, had a substantial loss of intestinal barrier function early in the course of infection. Epithelial cell apoptosis was significantly increased in GC-C-/- mice following 10 days of infection and this was associated with increased frequency and numbers of C. rodentium translocation out of the intestine. Infection led to significant liver histopathology in GC-C-/- mice as well as lymphocyte infiltration and elevated cytokine and chemokine expression. Relative to naïve GC-C+/+ mice, the commensal microflora load in uninfected GC-C-/- mice was decreased and bacterial composition was imbalanced and included outgrowth of the Enterobacteriacea family.This work demonstrates the novel finding that GC-C signaling is an essential component of host defense during murine enteric infection by reducing bacterial load and preventing systemic dissemination of attaching/effacing-lesion forming bacterial pathogens such as C. rodentium.

  View details for DOI 10.1186/1471-230X-13-135

  View details for Web of Science ID 000324144600001

  View details for PubMedID 24004613

  View details for PubMedCentralID PMC3766218

• Acid Suppression and the Risk of <i>Clostridium difficile</i> Infection JOURNAL OF PEDIATRICS Mezoff, E. A., Cohen, M. B. 2013; 163 (3): 627-630

  View details for DOI 10.1016/j.jpeds.2013.04.047

  View details for Web of Science ID 000323985300006

  View details for PubMedID 23759424

  View details for PubMedCentralID PMC3755114

• Importance of Addressing Anxiety in Youth With Functional Abdominal Pain: Suggested Guidelines for Physicians JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Cunningham, N. R., Lynch-Jordan, A., Mezoff, A. G., Farrell, M. K., Cohen, M. B., Kashikar-Zuck, S. 2013; 56 (5): 469-474

  Abstract

  Functional abdominal pain (FAP) is a common pediatric disorder associated with impairment in functioning that may persist for the long term. Anxiety is common in youth with FAP, and may be an important factor in predicting youth who are at greatest risk for increased impairment because of pain symptoms. In this article, we examine the relation between anxiety and impairment in youth with FAP. Furthermore, we explore various biopsychosocial factors (eg, neurobiological substrates, coping strategies, social factors) that may be implicated in the relation among FAP, anxiety, and increased impairment. Finally, we propose physician guidelines for screening and treatment of youth with FAP and co-occurring anxiety. Youth with FAP and co-occurring anxiety may benefit from cognitive-behavioral therapy in the context of multidisciplinary care.

  View details for DOI 10.1097/MPG.0b013e31828b3681

  View details for Web of Science ID 000318021900010

  View details for PubMedID 23412539

  View details for PubMedCentralID PMC4476243

• Recurrent pancreatitis in ornithine transcarbamylase deficiency MOLECULAR GENETICS AND METABOLISM Prada, C. E., Kaul, A., Hopkin, R. J., Page, K. I., Nathan, J. D., Bartholomew, D. W., Cohen, M. B., Heubi, J. E., Leslie, N. D., Burrow, T. 2012; 106 (4): 482-484

  Abstract

  Ornithine transcarbamylase (OTC) deficiency is a urea cycle defect with varying frequency and severity of episodes of hyperammonemia. We report three patients with OTC deficiency with recurrent pancreatitis. The pathogenesis of acute pancreatitis in this patient population requires further elucidation. Pancreatitis significantly affected dietary/metabolic management and increased frequency of hospitalizations.

  View details for DOI 10.1016/j.ymgme.2012.06.005

  View details for Web of Science ID 000307322100014

  View details for PubMedID 22728053

• sTREM-1 and LBP in Central Venous Catheter-associated Bloodstream Infections in Pediatric Intestinal Failure JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Kevan, E. N., Simmons, J. R., Kocoshis, S. A., Cohen, M. B., Rudolph, J. A. 2011; 53 (6): 627-633

  Abstract

  Central venous catheter-associated bloodstream infections (CVC-BSIs) are a major cause of morbidity and mortality in the pediatric intestinal failure (IF) population. We assessed plasma lipopolysaccharide-binding protein (LBP) and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) as biomarkers for CVC-BSI. We hypothesized that sTREM-1 and LBP rise with BSI and decline following treatment, and that baseline LBP is higher in the IF population than in controls.Patients younger than 4 years were recruited from the IF registry at Cincinnati Children's Hospital. LBP and sTREM-1 levels were measured on 22 patients with IF at baseline, 17 patients with IF with BSIs, and 11 healthy controls.Mean sTREM-1 level (pg/mL) and LBP level (μg/mL) rose with CVC-BSI over baseline (115.0 ± 51.2 vs 85.9 ± 27.6, P = 0.011 and 79.8 ± 45.4 vs 20.5 ± 11.3, P < 0.001, respectively) and declined following antibiotic therapy (115.0 ± 51.2 vs 77.9 ± 29.8, P = 0.003 and 79.8 ± 45.4 vs 26.2 ± 10.8, P < 0.001, respectively). Receiver operating characteristic curves showed that neither sTREM-1 nor LBP is sufficient to predict bacteremia versus fever without bacteremia (area under these curves = 0.57 and 0.82, respectively). Baseline LBP was higher in hospitalized patients than in outpatients (27.5 ± 8.7 vs 13.5 ± 9.2, P = 0.002), patients with previous BSIs versus those without (23.5 ± 10.4 vs 10.1 ± 8.3, P = 0.016), and those listed for transplantation versus those not listed (29.6 ± 9.8 vs 16.2 ± 9.5, P = 0.033).sTREM-1 and LBP rise with CVC-BSI in IF and decline after treatment; however, neither distinguishes infection from nonbacteremic febrile episodes. Baseline LBP may be a marker of disease severity in IF.

  View details for DOI 10.1097/MPG.0b013e3182294fcc

  View details for Web of Science ID 000297542700011

  View details for PubMedID 21701408

• Role for the Membrane Receptor Guanylyl Cyclase-C in Attention Deficiency and Hyperactive Behavior SCIENCE Gong, R., Ding, C., Hu, J., Lu, Y., Liu, F., Mann, E., Xu, F., Cohen, M. B., Luo, M. 2011; 333 (6049): 1642-1646

  Abstract

  Midbrain dopamine neurons regulate many important behavioral processes, and their dysfunctions are associated with several human neuropsychiatric disorders such as attention deficit hyperactivity disorder (ADHD) and schizophrenia. Here, we report that these neurons in mice selectively express guanylyl cyclase-C (GC-C), a membrane receptor previously thought to be expressed mainly in the intestine. GC-C activation potentiates the excitatory responses mediated by glutamate and acetylcholine receptors via the activity of guanosine 3',5'-monophosphate-dependent protein kinase (PKG). Mice in which GC-C has been knocked out exhibit hyperactivity and attention deficits. Moreover, their behavioral phenotypes are reversed by ADHD therapeutics and a PKG activator. These results indicate important behavioral and physiological functions for the GC-C/PKG signaling pathway within the brain and suggest new therapeutic targets for neuropsychiatric disorders related to the malfunctions of midbrain dopamine neurons.

  View details for DOI 10.1126/science.1207675

  View details for Web of Science ID 000294900900047

  View details for PubMedID 21835979

• What Have We Learned About Early Treatment of <i>Pseudomonas aeruginosa</i> Infection in Infants and Children With Cystic Fibrosis? ARCHIVES OF PEDIATRICS & ADOLESCENT MEDICINE Saiman, L., Cohen, M. B. 2011; 165 (9): 867-868

  View details for DOI 10.1001/archpediatrics.2011.133

  View details for Web of Science ID 000294537100016

  View details for PubMedID 21893653

• Murine Guanylate Cyclase C Regulates Colonic Injury and Inflammation JOURNAL OF IMMUNOLOGY Steinbrecher, K. A., Harmel-Laws, E., Garin-Laflam, M. P., Mann, E. A., Bezerra, L. D., Hogan, S. P., Cohen, M. B. 2011; 186 (12): 7205-7214

  Abstract

  Guanylate cyclase C (GUCY2C or GC-C) and its ligands, guanylin (GUCA2A or Gn) and uroguanylin (GUCA2B or Ugn), are expressed in intestinal epithelial cells and regulate ion secretion, intestinal barrier function, and epithelial monolayer homeostasis via cGMP-dependent signaling pathways. The aim of this study was to determine whether GC-C and its ligands direct the course of intestinal inflammation. In this article, we show that dextran sodium sulfate (DSS)-induced clinical disease and histological damage to the colonic mucosa were significantly less severe in GC-C(-/-) mice and moderately reduced in Gn(-/-) animals. Relative to wild-type controls, GC-C(-/-) and Gn(-/-) mice had reduced apoptosis and increased proliferation of intestinal epithelial cells during DSS colitis. Basal and DSS-induced production of resistin-like molecule β (RELMβ) was substantially diminished in GC-C(-/-) mice. RELMβ is thought to stimulate cytokine production in macrophages in this disease model and, consistent with this, TNF-α and IFN-γ production was minimal in GC-C(-/-) animals. RELMβ and cytokine levels were similar to wild-type in Gn(-/-) mice, however. Colonic instillation of recombinant RELMβ by enema into GC-C(-/-) mice restores sensitivity to DSS-mediated mucosal injury. These findings demonstrate a novel role for GC-C signaling in facilitating mucosal wounding and inflammation, and further suggest that this may be mediated, in part, through control of RELMβ production.

  View details for DOI 10.4049/jimmunol.1002469

  View details for Web of Science ID 000291309700062

  View details for PubMedID 21555532

  View details for PubMedCentralID PMC3110533

• <i>Clostridium difficile</i> Infection in Hospitalized Children in the United States ARCHIVES OF PEDIATRICS & ADOLESCENT MEDICINE Nylund, C. M., Goudie, A., Garza, J. M., Fairbrother, G., Cohen, M. B. 2011; 165 (5): 451-457

  Abstract

  To evaluate the trend in Clostridium difficile infection (CDI) among hospitalized children in the United States and to evaluate the severity of and risk factors associated with these cases of CDI.A retrospective cohort study using the triennial Healthcare Cost and Utilization Project Kids' Inpatient Database for the years 1997, 2000, 2003, and 2006.Hospitalized children in the United States.A nationally weighted number of patients (10 474 454) discharged from the hospital, 21 274 of whom had CDI.Discharge diagnosis of CDI.Trend in cases of CDI; effect and severity were measured by length of hospital stay, hospitalization charges, colectomy rate, and death rate.There was an increasing trend in cases of CDI, from 3565 cases in 1997 to 7779 cases in 2006 (P < .001). Patients with CDI had an increased risk of death (adjusted odds ratio [OR], 1.20; 95% confidence interval [95% CI], 1.01-1.43), colectomy (adjusted OR, 1.36; 95% CI, 1.04-1.79), a longer length of hospital stay (adjusted OR, 4.34; 95% CI, 3.97-4.83), and higher hospitalization charges (adjusted OR, 2.12; 95% CI, 1.98-2.26). There was no trend in death, colectomy, length of hospital stay, or hospitalization charges during the 4 time periods (ie, 1997, 2000, 2003, and 2006). The risk of comorbid diagnoses associated with CDI included inflammatory bowel disease, with an OR of 11.42 (95% CI, 10.16-12.83), and other comorbid diagnoses associated with immunosuppression or antibiotic administration.There is an increasing trend in CDI among hospitalized children, and this disease is having a significant effect on these children. In contrast to adults, there is no increasing trend in the severity of CDI in children. Children with medical conditions (including inflammatory bowel disease and immunosuppression) or conditions requiring antibiotic administration are at high risk of CDI.

  View details for DOI 10.1001/archpediatrics.2010.282

  View details for Web of Science ID 000290113500012

  View details for PubMedID 21199971

  View details for PubMedCentralID PMC4683604

• <i>Clostridium difficile</i> Infection and Treatment in the Pediatric Inflammatory Bowel Disease Population JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Mezoff, E., Mann, E. A., Hart, K., Lindsell, C. J., Cohen, M. B. 2011; 52 (4): 437-441

  Abstract

  Recent changes in the epidemiology of Clostridium difficile infection include an increase in the incidence of C difficile-associated disease (CDAD) and the identification of patients with inflammatory bowel disease (IBD) as a group at risk. In addition, the effectiveness of antimicrobial therapies has been questioned. Our aim was to estimate the incidence of CDAD in a pediatric IBD population and review treatment efficacy.We identified patients ages 18 years or younger from our center's IBD database who tested positive for C difficile toxin A and/or B between August 1, 2007 and December 31, 2008. Demographic information and treatment details were recorded. Chi-square and Fisher exact tests were used to compare categorical variables and the Student t test was used for continuous variables.From 372 pediatric patients with IBD, we identified 29 patients who experienced a total of 40 cases of CDAD. The annualized incidence rate of CDAD was 7.2%. Initial treatment was successful in 17 cases (43%). Eventual success was documented with metronidazole in 15 cases (41%), with vancomycin in 16 cases (43%), and with other agents or a combination of agents in 6 cases (16%). Age, sex, and IBD type were not associated with initial treatment outcome or recurrence. The choice of initial antimicrobial treatment was not associated with treatment outcome. The type of IBD therapy medication was not associated with the likelihood of CDAD recurrence, although the use of anti-inflammatory therapy was positively associated with initial antimicrobial treatment success.CDAD occurred frequently in our cohort of pediatric patients with IBD. Antimicrobial treatment success was achieved equally with either metronidazole or vancomycin. Initial treatment failed more than half of the time, regardless of medication choice. Apparent lack of antimicrobial efficacy in resolving symptoms may reflect resistant C difficile infection or increased IBD severity in a subset of patients who are C difficile carriers. Awareness of the potential for a high incidence of CDAD and frequent failure rate of initial therapy is important in the management of children with IBD.

  View details for DOI 10.1097/MPG.0b013e3181f97209

  View details for Web of Science ID 000288541100014

  View details for PubMedID 21407116

  View details for PubMedCentralID PMC3075442

• Transmembrane guanylate cyclase in intestinal pathophysiology CURRENT OPINION IN GASTROENTEROLOGY Steinbrecher, K. A., Cohen, M. B. 2011; 27 (2): 139-145

  Abstract

  Production of cyclic guanosine monophosphate (cGMP) by guanylate cyclase is of critical importance to gastrointestinal physiology. Tight regulation of cGMP concentration is necessary for proper intestinal secretion and intestinal epithelial cell proliferative and apoptotic homeostasis. This review focuses on recent work detailing the role of a subset of transmembrane guanylate cyclases in the pathophysiology of intestinal secretory and motility disorders and intestinal epithelial cell transformation. Also considered is the potential for therapeutic manipulation of intestinal guanylate cyclase/cGMP signaling for the correction of chronic constipation and gastrointestinal cancer.Recent work in mice and humans suggests a role for transmembrane guanylate cyclases in intestinal fluid secretion as well as hormonal enteric-renal signaling which mediates postprandial natriuresis. Transmembrane guanylate cyclases are also important in gastrointestinal transit rate and motility. Ongoing clinical trials have found that guanylate cyclase activating peptides are safe and effective in the treatment of constipation-predominant irritable bowel syndrome and chronic constipation. In addition, accumulating evidence indicates that membrane-associated guanylate cyclase receptors regulate intestinal epithelial cell homeostatic proliferation and apoptosis as well as gastrointestinal malignancy. The anticancer activity of cGMP signaling in animal studies suggests additional therapeutic applications for guanylate cyclase agonists.Progress toward understanding gastrointestinal transmembrane guanylate cyclase/cGMP physiology has recently accelerated due to definitive in-vitro studies and work using gene-targeted animal models and has facilitated the development of safe and effective drugs designed to regulate cGMP production in the intestine. Current work should be directed toward a detailed understanding of cGMP effector pathways and the manner in which subcellular concentrations of cGMP regulate them to influence intestinal health and disease.

  View details for DOI 10.1097/MOG.0b013e328341ead5

  View details for Web of Science ID 000287188900007

  View details for PubMedID 21102322

• Loss of Guanylyl Cyclase C (GCC) Signaling Leads to Dysfunctional Intestinal Barrier PLOS ONE Han, X., Mann, E., Gilbert, S., Guan, Y., Steinbrecher, K. A., Montrose, M. H., Cohen, M. B. 2011; 6 (1): e16139

  Abstract

  Guanylyl Cyclase C (GCC) signaling via uroguanylin (UGN) and guanylin activation is a critical mediator of intestinal fluid homeostasis, intestinal cell proliferation/apoptosis, and tumorigenesis. As a mechanism for some of these effects, we hypothesized that GCC signaling mediates regulation of intestinal barrier function.Paracellular permeability of intestinal segments was assessed in wild type (WT) and GCC deficient (GCC-/-) mice with and without lipopolysaccharide (LPS) challenge, as well as in UGN deficient (UGN-/-) mice. IFNγ and myosin light chain kinase (MLCK) levels were determined by real time PCR. Expression of tight junction proteins (TJPs), phosphorylation of myosin II regulatory light chain (MLC), and STAT1 activation were examined in intestinal epithelial cells (IECs) and intestinal mucosa. The permeability of Caco-2 and HT-29 IEC monolayers, grown on Transwell filters was determined in the absence and presence of GCC RNA interference (RNAi). We found that intestinal permeability was increased in GCC-/- and UGN-/- mice compared to WT, accompanied by increased IFNγ levels, MLCK and STAT1 activation in IECs. LPS challenge promotes greater IFNγ and STAT1 activation in IECs of GCC-/- mice compared to WT mice. Claudin-2 and JAM-A expression were reduced in GCC deficient intestine; the level of phosphorylated MLC in IECs was significantly increased in GCC-/- and UGN-/- mice compared to WT. GCC knockdown induced MLC phosphorylation, increased permeability in IEC monolayers under basal conditions, and enhanced TNFα and IFNγ-induced monolayer hyperpermeability.GCC signaling plays a protective role in the integrity of the intestinal mucosal barrier by regulating MLCK activation and TJ disassembly. GCC signaling activation may therefore represent a novel mechanism in maintaining the small bowel barrier in response to injury.

  View details for DOI 10.1371/journal.pone.0016139

  View details for Web of Science ID 000286834300035

  View details for PubMedID 21305056

  View details for PubMedCentralID PMC3031533

• Lack of Guanylate Cyclase C results in increased mortality in mice following liver injury BMC GASTROENTEROLOGY Mann, E. A., Shanmukhappa, K., Cohen, M. B. 2010; 10: 86

  Abstract

  Guanylate Cyclase C (GC-C) expression in the intestine plays a role in the regulation of fluid and ion transport, as well as epithelial cell apoptosis and proliferation. In the adult rat liver, GC-C expression is increased in response to injury. We hypothesized that GC-C is required for repair/recovery from liver injury.We subjected wild type (WT) and GC-C deficient mice to acute liver injury with a single injection of the hepatotoxin carbon tetrachloride. Changes in the level of expression of GC-C and its ligands uroguanylin and guanylin were quantified by real-time PCR. Liver morphology, and hepatocyte necrosis, apoptosis and proliferation, were examined at 1-3 days post-injury in mice on a mixed genetic background. Survival was followed for 14 days after carbon tetrachloride injection in wild type and GC-C deficient mice on both a mixed genetic background and on an inbred C57BL6/J background.GC-C deficient mice on the mixed genetic background nearly all died (median survival of 5 days) following carbon tetrachloride injection while WT littermates experienced only 35% mortality. Elevated levels of TUNEL-positive hepatocyte death on post-injury day 1, increased apoptosis on day 2, and increased areas of centrilobular necrosis on days 2 and 3, were evident in livers from GC-C null mice compared to WT. Collectively these data suggest increased hepatocyte death in the GC-C null mice in the early time period after injury. This corresponds temporally with increased expression of GC-C and its ligands guanylin and uroguanylin in post-injury WT mouse liver. The hepatocyte proliferative response to injury was the same in both genotypes. In contrast, there was no difference in survival between GC-C null and WT mice on the inbred C57BL/6 J background in response to acute liver injury.Signalling via GC-C promotes hepatocyte survival in vivo and is required for effective recovery from acute toxic injury to the liver in a strain-specific manner.

  View details for DOI 10.1186/1471-230X-10-86

  View details for Web of Science ID 000282775100001

  View details for PubMedID 20678221

  View details for PubMedCentralID PMC2919440

• Linaclotide is a potent and selective guanylate cyclase C agonist that elicits pharmacological effects locally in the gastrointestinal tract LIFE SCIENCES Bryant, A. P., Busby, R. W., Bartolini, W. P., Cordero, E. A., Hannig, G., Kessler, M. M., Pierce, C. M., Solinga, R. M., Tobin, J. V., Mahajan-Miklos, S., Cohen, M. B., Kurtz, C. B., Currie, M. G. 2010; 86 (19-20): 760-765

  Abstract

  Linaclotide is an orally administered 14-amino acid peptide being developed for the treatment of constipation-predominant irritable bowel syndrome (IBS-C) and chronic constipation. We determined the stability of linaclotide in the intestine, measured the oral bioavailability, and investigated whether the pharmacodynamic effects elicited in rodent models of gastrointestinal function are mechanistically linked to the activation of intestinal guanylate cyclase C (GC-C).Linaclotide binding to intestinal mucosal membranes was assessed in competitive binding assays. Stability and oral bioavailability of linaclotide were measured in small intestinal fluid and serum, respectively, and models of gastrointestinal function were conducted using wild type (wt) and GC-C null mice.Linaclotide inhibited in vitro [(125)I]-STa binding to intestinal mucosal membranes from wt mice in a concentration-dependent manner. In contrast, [(125)I]-STa binding to these membranes from GC-C null mice was significantly decreased. After incubation in vitro in jejunal fluid for 30 min, linaclotide was completely degraded. Pharmacokinetic analysis showed very low oral bioavailability (0.10%). In intestinal secretion and transit models, linaclotide exhibited significant pharmacological effects in wt, but not in GC-C null mice: induction of increased fluid secretion into surgically ligated jejunal loops was accompanied by the secretion of elevated levels of cyclic guanosine-3',5'-monophosphate and accelerated gastrointestinal transit.Linaclotide is a potent and selective GC-C agonist that elicits pharmacological effects locally in the gastrointestinal tract. This pharmacological profile suggests that orally administered linaclotide may be capable of improving the abdominal symptoms and bowel habits of patients suffering from IBS-C and chronic constipation.

  View details for DOI 10.1016/j.lfs.2010.03.015

  View details for Web of Science ID 000277192500010

  View details for PubMedID 20307554

• Guanylate cyclase C-mediated antinociceptive effects of linaclotide in rodent models of visceral pain NEUROGASTROENTEROLOGY AND MOTILITY Eutamene, H., Bradesi, S., Larauche, M., Theodorou, V., Beaufrand, C., Ohning, G., Fioramonti, J., Cohen, M., Bryant, A. P., Kurtz, C., Currie, M. G., Mayer, E. A., Bueno, L. 2010; 22 (3): 312-e84

  Abstract

  BACKGROUND Linaclotide is a novel, orally administered investigational drug currently in clinical development for the treatment of constipation-predominant irritable bowel syndrome (IBS-C) and chronic idiopathic constipation. Visceral hyperalgesia is a major pathophysiological mechanism in IBS-C. Therefore, we investigated the anti-nociceptive properties of linaclotide in rodent models of inflammatory and non-inflammatory visceral pain and determined whether these pharmacological effects are linked to the activation of guanylate cyclase C (GC-C). METHODS Orally administered linaclotide was evaluated in non-inflammatory acute partial restraint stress (PRS) and acute water avoidance stress (WAS) models in Wistar rats, and in a trinitrobenzene sulfonic acid (TNBS)-induced inflammatory model in Wistar rats and GC-C null mice. KEY RESULTS In TNBS-induced colonic allodynia, linaclotide significantly decreased the number of abdominal contractions in response to colorectal distension without affecting the colonic wall elasticity change in response to distending pressures after TNBS. However, linaclotide had no effect on visceral sensitivity under basal conditions. In addition, linaclotide significantly decreased colonic hypersensitivity in the PRS and WAS models. In wild type (wt) and GC-C null mice, the instillation of TNBS induced similar hyperalgesia and allodynia. However, in post-inflammatory conditions linaclotide significantly reduced hypersensitivity only in wt mice, but not in GC-C null mice. CONCLUSIONS & INFERENCES These findings indicate that linaclotide has potent anti-nociceptive effects in several mechanistically different rodent models of visceral hypersensitivity and that these pharmacological properties of linaclotide are exerted through the activation of the GC-C receptor. Therefore, linaclotide may be capable of decreasing abdominal pain in patients suffering from IBS-C.

  View details for DOI 10.1111/j.1365-2982.2009.01385.x

  View details for Web of Science ID 000274336200011

  View details for PubMedID 19706070

• State of Research in Pediatric Gastroenterology, Hepatology, and Nutrition: 2010 and Beyond GASTROENTEROLOGY Walker, W., Sherman, P., Shneider, B. L., Cohen, M., Barnard, J. 2010; 138 (2): 411-U24

  View details for DOI 10.1053/j.gastro.2009.12.034

  View details for Web of Science ID 000274300900004

  View details for PubMedID 20025876

• Teaching and Tomorrow: A Novel Recruitment Program for a Pediatric Subspecialty JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Graham, R. C., Heubi, J. E., Cohen, M. B., Li, B. K. 2009; 49 (5): 594-598

  Abstract

  : In 2001, the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition created Teaching and Tomorrow, a novel pediatric subspecialty recruitment program to provide prospective fellows the opportunity to participate in the society's annual meeting and to interact with current trainees and members. The aims of this report are to describe participant survey data from the first 4 years of the program and to explore potential influences of participation on outcomes and proposed career choices.: Pre- and postprogram surveys were administered during opening and closing breakfast meetings, respectively, to ascertain demographics, certainty of career intent, factors influencing choice of specialty, and anticipated benefits from participation.: Among 189 applications, 107 (57%) participated and 107 (57%) matriculated into gastroenterology(GI) fellowship. The matriculation rate was similar between participants and nonparticipants. Among applicants who became GI fellows, there was a 42% lower odds of being female than male (OR 0.42; chi = 8.48, P < 0.01). Among participants who completed both pre- and postprogram surveys (n = 91) and who reported certainty about entering GI both before and after, 79% entered GI fellowship. Among participants who reported uncertainty about entering GI both before and after, 8% entered GI. More participants were interested in jobs as clinician-investigators and funded clinical or translational investigators.: In a selected population of pediatric residents with high interest in pediatric gastroenterology, there was no difference in the matriculation rate into pediatric GI fellowship training among those who participated compared with those who did not. However, those who eventually matriculated had a higher odds of being male than female. There was a high retention rate of participants who were initially certain and a modest conversion rate of those who were initially uncertain about pursuing a career in pediatric GI.

  View details for DOI 10.1097/MPG.0b013e31819ca1a4

  View details for Web of Science ID 000271666500009

  View details for PubMedID 19644399

• <i>Clostridium difficile</i> Infections: Emerging Epidemiology and New Treatments Cohen, M. B. LIPPINCOTT WILLIAMS & WILKINS. 2009: S63-S65

  Abstract

  Clostridium difficile infections (CDIs) are increasingly a cause of morbidity and mortality. Although the pathogenicity of C difficile is based on toxin A and B expression, new hypervirulent strains express novel virulence factors. The etiology of recent increases in prevalence and severity of disease is not clearly explained by known mechanisms. New at-risk groups include children (without prior antibiotic exposure) and patients with inflammatory bowel disease. Vancomycin has an important role in the treatment of CDIs, but does not prevent recurrence. Other therapies for recurrent disease include antibiotics, probiotics, and immunotherapy. Novel therapies are under investigation for recurrent and resistant CDI.

  View details for DOI 10.1097/MPG.0b013e3181a118c6

  View details for Web of Science ID 000264671900009

  View details for PubMedID 19300129

• Activation of guanylate cyclase C signaling pathway protects intestinal epithelial cells from acute radiation-induced apoptosis AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY Garin-Laflam, M. P., Steinbrecher, K. A., Rudolph, J. A., Mao, J., Cohen, M. B. 2009; 296 (4): G740-G749

  Abstract

  Uroguanylin (UGN) is a peptide hormone that binds to and activates the intestinal epithelial cell (IEC) transmembrane receptor guanylate cyclase C (GC-C), which in turn increases intracellular cGMP. Gene targeting of murine UGN or GC-C results in significantly lower levels of cGMP in IECs. On the basis of effects of cGMP in nonintestinal systems, we hypothesized that loss of GC-C activation would increase intestinal epithelial apoptosis following radiation-induced injury. We first compared apoptosis from the proximal jejunum of C57BL/6 wild-type (WT) and GC-C knockout (KO) mice 3 h after they received 5 Gy of gamma-irradiation. We then investigated whether supplementation via intraperitoneal injection of 1 mM 8BrcGMP would mitigate radiation-induced apoptosis in these experimental animals. Identical experiments were performed in BALB/c UGN WT and KO mice. Apoptosis was assessed by quantitating morphological indications of cell death, terminal dUTP nick-end labeling, and cleaved caspase 3 immunohistochemistry. Both UGN KO and GC-C KO mice were more susceptible than their WT littermates in this in vivo model of apoptotic injury. Furthermore, cGMP supplementation in both GC-C and UGN KO animals ameliorated radiation-induced apoptosis. Neither WT strain demonstrated significant alteration in apoptotic susceptibility as a result of cGMP supplementation before radiation injury. These in vivo findings demonstrate increased radiosensitivity of IECs in UGN and GC-C KO mice and a role for cGMP as a primary downstream mediator of GC-C activation in the protection of these IECs from radiation-induced apoptosis.

  View details for DOI 10.1152/ajpgi.90268.2008

  View details for Web of Science ID 000264706400007

  View details for PubMedID 19221018

  View details for PubMedCentralID PMC2670662

• Heat-stable enterotoxin of Escherichia coli (STa) can stimulate duodenal HCO3- secretion via a novel GC-C- and CFTR-independent pathway FASEB JOURNAL Sellers, Z. M., Mann, E., Smith, A., Ko, K. H., Giannella, R., Cohen, M. B., Barrett, K. E., Dong, H. 2008; 22 (5): 1306-1316

  Abstract

  The heat-stable enterotoxin of Escherichia coli (STa) is a potent stimulant of intestinal chloride and bicarbonate secretion. Guanylyl cyclase C (GC-C) has been shown to be the primary receptor involved in mediating this response. However, numerous studies have suggested the existence of an alternative STa-binding receptor. The aims of this study were to determine whether a non-GC-C receptor exists for STa and what is the functional relevance of this for intestinal bicarbonate secretion in mice. (125)I-STa-binding experiments were performed with intestinal mucosae from GC-C knockout (KO) and wild type (WT) mice. Subsequently, the functional relevance of an alternative STa-binding receptor was explored by examining STa-, uroguanylin-, and guanylin-stimulated duodenal bicarbonate secretion (DBS) in GC-C KO mice in vitro and in vivo. Significant (125)I-STa-binding occurred in the proximal small intestines of GC-C KO and WT mice. Analysis of binding coefficients and pH dependence showed that (125)I-STa-binding in GC-C KO mice involved a receptor distinct from that of WT mice. Functionally, STa, uroguanylin, and guanylin all stimulated a significant increase in DBS in GC-C KO mice. Uroguanylin- and guanylin-stimulated DBS were significantly inhibited by glibenclamide, but not by 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid (DIDS). However, STa-stimulated DBS was unaffected by glibenclamide but inhibited by DIDS. Taken together, our results suggest that alternative, non-GC-C, receptors likely exist for STa, uroguanylin, and guanylin in the intestines of mice. While uroguanylin- and guanylin-stimulated DBS are cystic fibrosis transmembrane conductance regulator (CFTR) dependent, STa-stimulated DBS is CFTR independent. Further understanding of this alternative receptor and its signaling pathway may provide important insights into rectification of intestinal bicarbonate secretion in cystic fibrosis.

  View details for DOI 10.1096/fj.06-7540com

  View details for Web of Science ID 000255898700004

  View details for PubMedID 18096816

• Presentation of the 2007 Murray Davidson award to Michael K. Farrell, MD JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Cohen, M. B. 2008; 46 (1): 3

  View details for DOI 10.1097/01.mpg.0000304446.61681.ff

  View details for Web of Science ID 000251792200003

  View details for PubMedID 18162826

• Molecular cloning and promoter analysis of downregulated in adenoma (DRA) AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY Alrefai, W. A., Wen, X., Jiang, W., Katz, J. P., Steinbrecher, K. A., Cohen, M. B., Williams, I. R., Dudeja, P. K., Wu, G. D. 2007; 293 (5): G923-G934

  Abstract

  Downregulated in adenoma (DRA), also referred to as SLC26A3, is an intestinal anion transporter essential for intestinal chloride absorption. Mutations in DRA result in congenital chloride diarrhea. DRA expression has been shown to be induced by differentiation and to be modulated by cytokines. However, mechanisms of DRA gene transcription and its tissue-specific targeting have not yet been investigated. In this study, we cloned a 3,765-bp promoter fragment of human DRA gene and characterized its activity in human colonic LS174T and Caco-2 human colon cell lines. Primer extension identified a single transcriptional initiation site that was identical in both colon cancer cell lines and normal colon. Although hepatic nuclear factor HNF-4 is involved in the basal activity of DRA promoter, sodium butyrate induces its activity in LS174T cells via the binding of Yin Yang 1 (YY1) and GATA transcription factors to their respective cis-elements in promoter region. We also demonstrated a reduction in DRA promoter activity in Caco-2 cells by IFN-gamma, suggesting that regulation of DRA promoter by IFN-gamma may contribute to the pathophysiology of intestinal inflammation. Furthermore, we showed that the DRA promoter fragment is sufficient to drive human growth hormone transgene expression specifically in villus epithelial cells of the small intestine and in differentiated upper crypt and surface epithelial cells of the colon. Our studies provide evidence for the involvement of HNF-4, YY1, and GATA transcription factors in DRA expression in intestinal differentiated epithelial cells.

  View details for DOI 10.1152/ajpgi.00029.2007

  View details for Web of Science ID 000250709000002

  View details for PubMedID 17761837

• An eosinophil hypothesis for functional dyspepsia CLINICAL GASTROENTEROLOGY AND HEPATOLOGY Rothenberg, M. E., Cohen, M. B. 2007; 5 (10): 1147-1148

  View details for DOI 10.1016/j.cgh.2007.07.025

  View details for Web of Science ID 000250363600007

  View details for PubMedID 17916543

• How safe is intravenous sedation with midazolam and fentanyl for pediatric gastrointestinal endoscopy? NATURE CLINICAL PRACTICE GASTROENTEROLOGY & HEPATOLOGY Cohen, M. B., Gunter, J. B. 2007; 4 (10): 538-539

  View details for DOI 10.1038/ncpgasthep0924

  View details for Web of Science ID 000249824100004

  View details for PubMedID 17712323

• Suppurative peripheral arthritis in inflammatory bowel disease JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Pasternak, B., Grom, A., Yazigi, N., Cohen, M. B. 2007; 45 (1): 117-120

  View details for DOI 10.1097/MPG.0b013e3180308d3c

  View details for Web of Science ID 000247551100018

  View details for PubMedID 17592374

• Novel mechanism of cyclic AMP mediated extracellular signal regulated kinase activation in an intestinal cell line CELLULAR SIGNALLING Rudolph, J. A., Pratt, J., Mourya, R., Steinbrecher, K. A., Cohen, M. B. 2007; 19 (6): 1221-1228

  Abstract

  The extracellular signal regulated kinase (ERK1/2) signaling cascade has been implicated as both a pro-apoptotic and anti-apoptotic pathway depending on cell type and context. In the T84 intestinal epithelial cell line, cAMP activates ERK1/2 resulting in the inhibition of apoptosis. Cyclic-AMP signaling relies on the binding and activation of a cAMP binding protein. In most cell types, the majority of this signaling occurs through an isoform of protein kinase A (PKAI or PKAII). Despite evidence to the contrary, we hypothesized that ERK1/2 activation is through a PKA isoform. Pharmacological activators and inhibitors of PKA as well as siRNA were used to further interrogate this potential signaling pathway. Our results demonstrate that at doses sufficient to increase PKA activity, PKAII specific cAMP analogs activate ERK1/2 while PKAI analogs do not. Pharmacological inhibition of the PKAII regulatory subunit and catalytic subunit as well as siRNA knockdown of the catalytic subunit blocks ERK1/2 activation. We conclude that in the T84 cell line, cAMP binding to the PKAII regulatory subunit leads to the subsequent phosphorylation of ERK1/2 and provides insight into the mechanism of cAMP mediated survival signaling in the intestinal epithelium. These results directly implicate PKAII as a mediator of cell survival in T84 cells and provide evidence for an additional means by which cAMP can influence intestinal cell turnover.

  View details for DOI 10.1016/j.cellsig.2007.01.002

  View details for Web of Science ID 000246437400013

  View details for PubMedID 17317103

• Gaucher disease: Progressive mesenteric and mediastinal lymphadenopathy despite enzyme therapy JOURNAL OF PEDIATRICS Burrow, T., Cohen, M. B., Bokulic, R., Deutsch, G., Choudhary, A., Falcone, R. A., Grabowski, G. A. 2007; 150 (2): 202-206

  Abstract

  A 5-year-old male with Gaucher's disease type 3 developed progressive mesenteric and mediastinal lymphadenopathy over 12 months, despite enzyme replacement therapy, contributing to the development of a protein-losing enteropathy. These complications are unique, indicating poorly accessible, differentially responsive compartments in patients with Gaucher's disease who are receiving enzyme therapy.

  View details for DOI 10.1016/j.jpeds.2006.10.062

  View details for Web of Science ID 000244111300021

  View details for PubMedID 17236903

• State of pediatric gastroenterology, hepatology, and nutrition: 2006 and beyond GASTROENTEROLOGY Walker, W., Sherman, P., Cohen, M., Barnard, J. 2007; 132 (1): 434-436

  View details for DOI 10.1053/j.gastro.2006.10.066

  View details for Web of Science ID 000243843500044

  View details for PubMedID 17241890

• Potential of blood eosinophils, eosinophil-derived neurotoxin, and eotaxin-3 as biomarkers of eosinophilic esophagitis CLINICAL GASTROENTEROLOGY AND HEPATOLOGY Konikoff, M. R., Blanchard, C., Kirby, C., Buckmeier, B. K., Cohen, M. B., Heubi, J. E., Putnam, P. E., Rothenberg, M. E. 2006; 4 (11): 1328-1336

  Abstract

  Eosinophilic esophagitis (EE) is an increasingly recognized disorder characterized by eosinophilic inflammation of the esophageal mucosa, and typically requires serial invasive endoscopic biopsy examinations to document the characteristic histologic features of the disorder. The aim of this study was to identify noninvasive biomarkers that correlated with disease activity and response to treatment as measured by esophageal eosinophilia.A prospective, cross-sectional analysis was performed on 47 pediatric patients undergoing endoscopic evaluation of possible EE. Blood samples were collected for measurement of peripheral blood absolute eosinophil count (AEC) and levels of eosinophil-derived neurotoxin (EDN), eotaxin-1, -2, and -3, and interleukin-5. Stool samples were collected for measurement of EDN. Biomarker levels were correlated with esophageal eosinophil density, and differences in biomarker levels based on disease activity and treatment were determined.AEC, plasma EDN levels, and eotaxin-3 levels significantly correlated with esophageal eosinophil density (AEC: r = 0.56, P < .0001; EDN: r = 0.54, P < .0001; eotaxin-3: r = 0.32, P = .04), and were increased in patients with active EE vs controls (AEC: 440 vs 140 eosinophils/muL, P < .05; EDN: 50.3 vs 31.1 ng/mL, P = .01; eotaxin-3: 37.7 vs 11.5 pg/mL, P = .01). Cut-off values were established to maximize the sensitivity, specificity, and predictive values of these biomarkers alone and in combination. Eotaxin-1, eotaxin-2, interleukin-5, and fecal EDN levels did not correlate with esophageal eosinophil density, and were not increased in active EE vs controls or those with inactive EE.These data show that blood levels of AEC, EDN, and eotaxin-3 may have value as noninvasive biomarkers for monitoring EE.

  View details for DOI 10.1016/j.cgh.2006.08.013

  View details for Web of Science ID 000242263800010

  View details for PubMedID 17059896

• A randomized, double-blind, placebo-controlled trial of fluticasone propionate for pediatric eosinophilic esophagitis GASTROENTEROLOGY Konikoff, M. R., Noel, R. J., Blanchard, C., Kirby, C., Jameson, S. C., Buckmeier, B. K., Akers, R., Cohen, M. B., Collins, M. H., Assa'ad, A. H., Aceves, S. S., Putnam, P. E., Rothenberg, M. E. 2006; 131 (5): 1381-1391

  Abstract

  Eosinophilic esophagitis is an increasingly recognized disorder with distinctive endoscopic, histologic, and allergic features. Although several therapies are advocated, no placebo-controlled trials have been conducted. We aimed to determine the efficacy of swallowed fluticasone propionate (FP) in the treatment of eosinophilic esophagitis.We conducted a randomized, double-blind, placebo-controlled trial of swallowed FP in pediatric patients with active eosinophilic esophagitis. Thirty-six patients were randomly assigned to receive either 880 mug of FP (21 patients) or placebo (15 patients) divided twice daily for 3 months. The primary end point was histologic remission, defined by a peak eosinophil count of

  View details for DOI 10.1053/j.gastro.2006.08.033

  View details for Web of Science ID 000242221000010

  View details for PubMedID 17101314

• The <i>Bacteroides fragilis</i> toxin binds to a specific intestinal epithelial cell receptor INFECTION AND IMMUNITY Wu, S., Shin, J., Zhang, G., Cohen, M., Franco, A., Sears, C. L. 2006; 74 (9): 5382-5390

  Abstract

  The Bacteroides fragilis toxin (BFT) is the only known virulence factor of enterotoxigenic B. fragilis. BFT has previously been shown to act, at least in part, through cleavage of the intercellular adhesion protein E-cadherin. A specific cellular receptor for BFT has not been identified. The goal of this study was to determine if the initial interaction of BFT with intestinal epithelial cells was consistent with binding to a specific cellular receptor. Purified BFT was labeled with a fluorophore or iodide to assess specific cellular binding and the properties of BFT cellular binding. BFT binds specifically to intestinal epithelial cell lines in vitro in a polarized manner. However, specific binding occurs only at 37 degrees C and requires BFT metalloprotease activity. The BFT receptor is predicted to be a membrane protein other than E-cadherin or a known protease-activated receptor (PAR1 to PAR4). BFT binding is resistant to acid washing, suggesting an irreversible interaction. Sugar or lipid residues do not appear to be involved in the mechanism of BFT cellular binding, but binding is sensitive to membrane cholesterol depletion. We conclude that intestinal epithelial cells in vitro possess a specific membrane BFT receptor that is distinct from E-cadherin. The data favor a model in which the metalloprotease domain of BFT processes its receptor protein, initiating cellular signal transduction that mediates the biological activity of BFT. However, activation of recognized protease-activated receptors does not mimic or block BFT biological activity or binding, suggesting that additional protease-activated receptors on intestinal epithelial cells remain to be identified.

  View details for DOI 10.1128/IAI.00060-06

  View details for Web of Science ID 000240296400047

  View details for PubMedID 16926433

  View details for PubMedCentralID PMC1594844

• The proximal convoluted tubule is a target for the uroguanylin-regulated natriuretic response JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Elitsur, N., Lorenz, J. N., Hawkins, J. A., Rudolph, J. A., Witte, D., Yang, L. E., McDonough, A. A., Cohen, M. B. 2006; 43: S74-S81

  Abstract

  Guanylin and uroguanylin are peptides synthesized in the intestine and kidney that are postulated to have both paracrine and endocrine functions, forming a potential enteric-renal link to coordinate salt ingestion with natriuresis. To explore the in vivo role of guanylin and uroguanylin in the regulation of sodium excretion, we used gene-targeted mice in which the uroguanylin, guanylin or the peptide receptor guanylate cyclase C gene expression had been ablated.Metabolic balance studies demonstrated that there was impaired excretion of a sodium load in uroguanylin (but not in guanylin or guanylate cyclase C) knockout mice. Uroguanylin-dependent natriuresis occurred without an increase in circulating prouroguanylin. A distinct morphological phenotype was present in the proximal convoluted tubules of uroguanylin knockout animals after an enteral salt loading. Marked vacuolization of the proximal convoluted tubule epithelial cells was observed by using light and electron microscopy. There was also a change in the distribution of the sodium hydrogen exchanger 3 (NHE3) after an enteral salt loading. In wild-type animals, there was a partial redistribution of NHE3 from the villus fraction to the less accessible submicrovillus membrane compartment, but this effect was less apparent in uroguanylin knockout animals, presumably resulting in greater Na/H exchange.Together, these findings further establish a role for uroguanylin in fluid homeostasis and support a role for uroguanylin as an integral component of a signaling mechanism that mediates changes in Na excretion in response to an enteral salt loading. Proximal tubular NHE3 activity is a possible target for uroguanylin-mediated changes in Na excretion.

  View details for DOI 10.1097/01.mpg.0000228092.36089.7c

  View details for Web of Science ID 000239067100013

  View details for PubMedID 16819406

• Festschrift introduction - William F. Balistreri JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Cohen, M. B. 2006; 43: S1-S3

  View details for DOI 10.1097/01.mpg.0000226383.33742.f0

  View details for Web of Science ID 000239067100001

• Eotaxin-3 and a uniquely conserved gene-expression profile in eosinophilic esophagitis JOURNAL OF CLINICAL INVESTIGATION Blanchard, C., Wang, N., Stringer, K. F., Mishra, A., Fulkerson, P. C., Abonia, J. P., Jameson, S. C., Kirby, C., Konikoff, M. R., Collins, M. H., Cohen, M. B., Akers, R., Hogan, S. P., Assa'ad, A. H., Putnam, P. E., Aronow, B. J., Rothenberg, M. E. 2006; 116 (2): 536-547

  Abstract

  Eosinophilic esophagitis (EE) is an emerging disorder with a poorly understood pathogenesis. In order to define disease mechanisms, we took an empirical approach analyzing esophageal tissue by a genome-wide microarray expression analysis. EE patients had a striking transcript signature involving 1% of the human genome that was remarkably conserved across sex, age, and allergic status and was distinct from that associated with non-EE chronic esophagitis. Notably, the gene encoding the eosinophil-specific chemoattractant eotaxin-3 (also known as CCL26) was the most highly induced gene in EE patients compared with its expression level in healthy individuals. Esophageal eotaxin-3 mRNA and protein levels strongly correlated with tissue eosinophilia and mastocytosis. Furthermore, a single-nucleotide polymorphism in the human eotaxin-3 gene was associated with disease susceptibility. Finally, mice deficient in the eotaxin receptor (also known as CCR3) were protected from experimental EE. These results implicate eotaxin-3 as a critical effector molecule for EE and provide insight into disease pathogenesis.

  View details for DOI 10.1172/JCI26679

  View details for Web of Science ID 000235043600031

  View details for PubMedID 16453027

  View details for PubMedCentralID PMC1359059

• Novel effects of the prototype translocating <i>Escherichia coli</i>, strain C25 on intestinal epithelial structure and barrier function CELLULAR MICROBIOLOGY Zareie, M., Riff, J., Donato, K., McKay, D. M., Perdue, M. H., Soderholm, J. D., Karmali, M., Cohen, M. B., Hawkins, J., Sherman, P. M. 2005; 7 (12): 1782-1797

  Abstract

  Intestinal bacteria play an etiologic role in triggering and perpetuating chronic inflammatory bowel disorders. However, the precise mechanisms whereby the gut microflora influences intestinal cell function remain undefined. Therefore, the effects of the non-pathogenic prototype translocating Escherichia coli, strain C25 on the barrier properties of human T84 and Madine-Darby canine kidney type 1 epithelial cells were examined. T-84 cells were also infected with commensal E. coil, strains F18 and HB101, and enterohaemorrhagic E. coli, serotype O157:H7. Strains F18 and HB101 had no effect on transepithelial electrical resistance (TER) of T84 monolayers. By contrast, epithelial cells infected with strain C25 displayed a time-dependent decrease in TER, preceded by an altered distribution of the cytoskeletal protein alpha-actinin, comparable to infection with E. coli O157:H7. E. coli C25 infection also led to activation of nuclear factor kappaB (NF-kappaB), interleukin-8 secretion and alterations in localization of claudin-1, but not zona occludens-1 or claudin-4, in T84 cells. There were adherent C25 bacteria on the intact apical surface of infected T84 cells, while mitochondria appeared swollen and vacuolated. These novel findings demonstrate the ability of a translocating commensal bacterium to adhere to and modulate intestinal epithelial barrier function and to induce morphological changes in a manner distinct from the known enteric pathogen, E. coli O157:H7.

  View details for DOI 10.1111/j.1462-5822.2005.00595.x

  View details for Web of Science ID 000233314800009

  View details for PubMedID 16309464

• Lack of guanylyl cyclase C, the receptor for <i>Escherichia coli</i> heat-stable enterotoxin, results in reduced polyp formation and increased apoptosis in the multiple intestinal neoplasia (Min) mouse model INTERNATIONAL JOURNAL OF CANCER Mann, E. A., Steinbrecher, K. A., Stroup, C., Witte, D. P., Cohen, M. B., Giannella, R. A. 2005; 116 (4): 500-505

  Abstract

  Guanylyl cyclase C (GC-C), a transmembrane receptor for bacterial heat-stable enterotoxin and the mammalian peptides guanylin and uroguanylin, mediates intestinal ion secretion and affects intestinal cell growth via cyclic GMP signaling. In intestinal tumors, GC-C expression is maintained while guanylin and uroguanylin expression is lost, suggesting a role for GC-C activation in tumor formation or growth. We show by in situ hybridization that GC-C expression is retained in adenomas from multiple intestinal neoplasia (Apc(Min/+)) mice. In order to determine the in vivo role of GC-C in intestinal tumorigenesis, we generated Apc(Min/+) mice homozygous for a targeted deletion of the gene encoding GC-C and hypothesized that these mice would have increased tumor multiplicity and size compared to wild-type Apc(Min/+) mice on the same genetic background. In contrast, the absence of GC-C resulted in a reduction of median polyp number by 55%. There was no change in the median diameter of polyps, suggesting no effect on tumor growth. Somatic loss of the wild-type Apc allele, an initiating event in intestinal tumorigenesis, also occurred in polyps from GC-C-deficient Apc(Min/+) mice. We have found increased levels of apoptosis as well as increased caspase-3 and caspase-7 gene expression in the intestines of GC-C-deficient Apc(Min/+) mice compared with Apc(Min/+) mice. We propose that these alterations are a possible compensatory mechanism by which loss of GC-C signaling also affects tumorigenesis.

  View details for DOI 10.1002/ijc.21119

  View details for Web of Science ID 000230935500002

  View details for PubMedID 15825168

• Prevalence and outcome of allergic colitis in healthy infants with rectal bleeding: A prospective cohort study JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Xanthakos, S. A., Schwimmer, J. B., Melin-Aldana, H., Rothenberg, M. E., Witte, D. P., Cohen, M. B. 2005; 41 (1): 16-22

  Abstract

  Allergic colitis is often diagnosed clinically in healthy infants with rectal bleeding and often treated with costly hypoallergenic formula. The true prevalence of allergic colitis is unknown. We tested the hypothesis that allergic colitis is overdiagnosed in healthy infants with rectal bleeding. The authors also determined whether rectal bleeding in infants without allergic colitis would resolve without diet change.For the purposes of this study, allergic colitis was defined histologically as colonic mucosa with >or= 6 eosinophils per high power field and/or eosinophils in colonic crypts or muscularis mucosae. We surveyed all 56 Ohio NASPGHAN members to determine standard practice regarding the evaluation of rectal bleeding in infants. In addition, infants

  View details for Web of Science ID 000230242800005

  View details for PubMedID 15990624

• Presentation of the Julius M Friedenwald medal to Ralph A Giannella, MD GASTROENTEROLOGY Cohen, M. B. 2005; 128 (7): 2152-2157

  View details for DOI 10.1053/j.gastro.2005.04.036

  View details for Web of Science ID 000229662900038

  View details for PubMedID 15940646

• National Institutes of Health Consensus Development Conference Statement on Celiac Disease, June 28-30, 2004 GASTROENTEROLOGY [Anonymous] 2005; 128 (4): S1-S9

  Abstract

  NIH consensus and state-of-the-science statements are prepared by independent panels of health professionals and public representatives on the basis of (1) the results of a systematic literature review prepared under contract with the Agency for Healthcare Research and Quality (AHRQ); (2) presentations by investigators working in areas relevant to the conference questions during a 2-day public session; (3) questions and statements from conference attendees during open discussion periods that are part of the public session; and (4) closed deliberations by the panel during the remainder of the second day and morning of the third. This statement is an independent report of the panel and is not a policy statement of the NIH or the Federal Government. The statement reflects the panel's assessment of medical knowledge available at the time the statement was written. Thus, it provides a "snapshot in time" of the state of knowledge on the conference topic. When reading the statement, keep in mind that new knowledge is inevitably accumulating through medical research.

  View details for DOI 10.1053/j.gastro.2005.02.007

  View details for Web of Science ID 000228337000001

  View details for PubMedID 15825115

• Prevalence of diarrheagenic Escherichia coli in acute childhood enteritis: A prospective controlled study JOURNAL OF PEDIATRICS Cohen, M. B., NATARO, J. P., BERNSTEIN, D. I., Hawkins, J., Roberts, N., Staat, M. A. 2005; 146 (1): 54-61

  Abstract

  Since diarrheagenic E. coli are not identified by common clinical laboratory techniques, we hypothesized that these organisms might be an unrecognized cause of enteritis in children in the U.S.1327 children with acute gastroenteritis were identified prospectively by active surveillance in the Emergency Department (ED) and the inpatient units at Cincinnati Children's Hospital Medical Center. Stool samples were evaluated for diarrheagenic E. coli using a panel of DNA probes and adherence pattern to HEp-2 cells. Stool samples from a reference group of 555 well children were studied for comparison.Gene probe studies, but not HEp-2 cell adherence, demonstrated that enteroaggregative, diffusely adherent and enteropathogenic E. coli were associated with clinical illness. Each was isolated significantly more often from study subjects in the ED than controls. In children <1 year of age, enteroaggregative E. coli were isolated significantly more often from both inpatients (4.7%, Odds Ratio = 3.4, 95% confidence intervals 1.3-9.1, p <0.03) and ED patients (10.0%, Odds Ratio = 7.2, 95% confidence intervals 2.9-18.2, p <0.001) than from well children (1.4%).Diarrheagenic E. coli , especially enteroaggregative E. coli , may be an important, unrecognized cause of childhood diarrhea in the U.S.

  View details for DOI 10.1016/j.jpeds.2004.08.059

  View details for Web of Science ID 000226337700016

  View details for PubMedID 15644823

• Duodenogastric intussusception: A rare cause of gastric outlet obstruction JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Osuntokun, B., Falcone, R., Alonso, M., Cohen, M. B. 2004; 39 (3): 299-301

  View details for DOI 10.1097/00005176-200409000-00015

  View details for Web of Science ID 000223570600015

  View details for PubMedID 15319634

• Cyclic AMP activation of the extracellular signal-regulated kinases 1 and 2 - Implications for intestinal cell survival through the transient inhibition of apoptosis JOURNAL OF BIOLOGICAL CHEMISTRY Rudolph, J. A., Poccia, J. L., Cohen, M. B. 2004; 279 (15): 14828-14834

  Abstract

  The proliferative compartment of the intestinal crypt is critical in the process of intestinal epithelial cell homeostasis. The ability of these progenitor crypt cells to resist apoptosis and ensure restitution during a potentially lethal insult, but retain the ability to remove damaged or altered cells afterward, is necessary for preservation of the crypt-villus unit. We have examined the ability of cAMP to transiently inhibit apoptosis via the extracellular signal-regulated kinases 1 and 2 (ERK1/2), in T84 cells, an intestinal crypt-like cell line. Using the cAMP analog 8-bromo-cAMP and cholera toxin (CT), cAMP-mediated ERK1/2 activation was first measured by Western blot analysis of the phosphorylated (activated) and total (activated and inactivated) forms of ERK1/2. Cyclic AMP activated ERK1/2 in a time- and dose-dependent manner, and the effect was inhibited by PD098059, an inhibitor of the ERK1/2 signaling pathway. However, inhibition of protein kinase A (PKA) did not alter the activation of ERK1/2. CT transiently inhibited both staurosporine and Fas antibody mediated apoptosis as measured by a caspase-3 activation assay and the detection of nucleosomes in an apoptosis based enzyme-linked immunosorbent assay. This inhibitory effect was reversed by the simultaneous addition of PD098059. Our data suggest that in the T84 cell line, cAMP activates ERK1/2 in a PKA independent fashion and a physiological consequence of this activated pathway is the transient inhibition of apoptosis. These findings suggest a novel pathway that intestinal cells use to protect against injury while maintaining the overall ability to remove damaged cells and preserve intestinal homeostasis.

  View details for DOI 10.1074/jbc.M310289200

  View details for Web of Science ID 000220594700043

  View details for PubMedID 14744867

• Effect of secretagogues and pH on intestinal transport in guanylin-deficient mice BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS Charney, A. N., Egnor, R. W., Steinbrecher, K. A., Cohen, M. B. 2004; 1671 (1-3): 79-86

  Abstract

  The small and large intestine secrete guanylin, a peptide homologous to heat stable enterotoxin (STa) elaborated by enterotoxigenic Escherichia coli. Guanylin's role in intestinal electrolyte transport was investigated in guanylin-deficient knockout mice and heterozygous littermate controls. Segments of mid-jejunum, distal ileum, and proximal and distal colon were studied in Ussing chambers in HCO3- Ringer under short circuit conditions. We found that (1) under basal conditions, all segments in control and knockout mice absorb Na+, and the knockout mouse proximal colon secretes Cl-; (2) all segments except the jejunum of knockout mice respond by increasing absorption in response to reductions in pH from 7.6 to 7.1; (3) all segments exhibit decreased absorption in response to 1 mM cAMP; (4) the jejunum and ileum of knockout and control mice, and the proximal colon of control mice (but not knockout mice) respond to the mucosal addition of 50 nM STa with decreases in absorption; and (5) mucosal guanylin caused similar decreases in proximal colon absorption in control and guanylin-deficient mice. These findings suggest that guanylin deficiency causes basal Cl- secretion and reduced responsiveness to STa in mouse proximal colon. The effectiveness of guanylin in this segment suggests a difference in the intestinal secretory actions of STa and guanylin.

  View details for DOI 10.1016/j.bbagen.2004.01.007

  View details for Web of Science ID 000220457300010

  View details for PubMedID 15026148

• Effect of triglyceride structure on fecal excretion of <SUP>13</SUP>C-labeled triglycerides JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION Schuette, S. A., Janghorbani, M., Cohen, M. B., Krug, S., Schindler, T., Wagner, D. A., DiMagno, E. P. 2003; 22 (6): 511-518

  Abstract

  The aim of this work was to determine the effects of specific changes in the structure of (13)C-labeled triglyceride (TG*) on its fecal excretion relative to total stool fat excretion determined simultaneously in patients with reduced exocrine pancreatic function.A series of 47 studies were conducted in 26 young cystic fibrosis (CF) patients and 11 adult patients with chronic pancreatitis over a five year period. Each test consisted of ingesting a single high fat test meal containing both (13)C-labeled triglyceride (TG*) and dysprosium chloride (DyCl(3)) a nonabsorbable marker of intestinal transit; in most studies the food colorant brilliant blue (FD&C blue #1) was administered along with the DyCl(3). The TG*s tested were: P*P*P* = TRIPALMITIN-1,1,1-(13)C(3); SO*S = 2-OCTANOYL-1,3-DISTEARIN-2-octanoyl-1,2-(13)C(2); and P*LP* = 2-LAURYL-1,3-DIPALMITIN-dipalmitoyl-1,1,2,2-(13)C(4). Ingestion of the test meal was followed by collection of individual stools for at least 72 hours. Stools were analyzed for (13)C-Excess ((13)C*), total fat, and Dy.Excretion of P*LP* showed a high degree of linear correlation with stool fat (r(2) = 0.924) over a wide-range of fecal fat values. Excretion of SO*S was also significantly correlated with stool fat, but its excretion was less than 10% at all levels of steatorrhea and the slope of the regression line relating TG* excretion to stool fat was some four to five times smaller than observed for P*LP*. Fecal excretion of P*P*P* was highly correlated with stool fat (r(2) = 0.941) in patients with moderate steatorrhea (<25 g fat/24 hours) and the slope of the regression line (3.20) was considerably greater than for P*LP*. Only results from those studies in which stool collections were complete (Dy excretion >90%) were utilized in the statistical comparisons (36 of 47 studies).The observed highly significant linear correlation between P*LP* and stool fat over the entire range of steatorrhea suggests that P*LP* excretion may be a suitable surrogate for fecal fat in patients with reduced exocrine pancreatic function. Because fecal excretion of TG* administered as described can be accurately determined by sampling only two visually marked stools, development of a noninvasive test to replace the current 72-hour stool fat test using this approach is possible. Use of other engineered TG*s and/or labeled fatty acids, may provide a method for non-invasive in vivo assessment of the specific defect(s) leading to steatorrhea in other patient groups.

  View details for DOI 10.1080/07315724.2003.10719329

  View details for Web of Science ID 000187444800004

  View details for PubMedID 14684756

• Dysprosium chloride as a nonabsorbable gastrointestinal marker for studies of stable isotope-labeled triglyceride excretion in man JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION Schuette, S. A., Janghorbani, M., Cohen, M. B., Krug, S., Schindler, T., Wagner, D. A., Morris, S. J. 2003; 22 (5): 379-387

  Abstract

  The aim of this work was to determine if dysprosium chloride (DyCl(3)) is a suitable nonabsorbable marker for studies of labeled-triglyceride excretion in cystic fibrosis patients allowing excretion to be determined accurately after analysis of one or two stools.A series of 66 absorption studies were conducted in 36 young cystic fibrosis patients over a five year period. All tests consisted of ingesting a single test meal containing both (13)C-labeled triglyceride (TG*) and DyCl(3); in most studies the food colorant brilliant blue (FD&C blue #1) was administered along with the DyCl(3). Ingestion of the test meal was followed by collection of individual stools for 72 to 96 hours. Stools were analyzed for (13)C-Excess ((13)C*) and Dy.Excretion of Dy in cystic fibrosis patients who exhibited a wide-range of steatorrhea was quantitative. Fractional excretion of Dy and (13)C* in individual stools showed a high linear correlation (r(2) = 0.969) with a slope and y-intercept close to unity and zero, respectively. As a result, estimates of TG* excretion based on analysis of only two stools (partial pool method, PPM) were not different from those based on the analysis of all stools or stool composites. This was true both when Dy content and when stool color due to ingested brilliant blue was used to determine which stools to analyze for the PPM.Combining the use of Dy and brilliant blue permits reasonably accurate estimates of fecal TG* excretion after analysis of samples from two easily identified stools. This practical method can be used to address many important clinical and experimental questions regarding triglyceride digestion and absorption that may otherwise go unanswered.

  View details for DOI 10.1080/07315724.2003.10719321

  View details for Web of Science ID 000185922700006

  View details for PubMedID 14559930

• Uroguanylin knockout mice have increased blood pressure and impaired natriuretic response to enteral NaCl load JOURNAL OF CLINICAL INVESTIGATION Lorenz, J. N., Nieman, M., Sabo, J., Sanford, L. P., Hawkins, J. A., Elitsur, N., Gawenis, L. R., Clarke, L. L., Cohen, M. B. 2003; 112 (8): 1244-1254

  Abstract

  Guanylin and uroguanylin, peptides synthesized in the intestine and kidney, have been postulated to have both paracrine and endocrine functions, forming a potential enteric-renal link to coordinate salt ingestion with natriuresis. To explore the in vivo role of uroguanylin in the regulation of sodium excretion, we created gene-targeted mice in which uroguanylin gene expression had been ablated. Northern and Western analysis confirmed the absence of uroguanylin message and protein in knockout mice, and cGMP levels were decreased in the mucosa of the small intestine. Ussing chamber analysis of jejunum revealed that Na+/H+ exchanger-mediated Na+ absorption and tissue conductance was not altered in the knockout animals, but short-circuit current, an index of electrogenic anion secretion, was reduced. Renal clearance measurements showed that uroguanylin deficiency results in impaired ability to excrete an enteral load of NaCl, primarily due to an inappropriate increase in renal Na+ reabsorption. Finally, telemetric recordings of blood pressure demonstrated increased mean arterial pressure in uroguanylin knockout animals that was independent of the level of dietary salt intake. Together, these findings establish a role for uroguanylin in an enteric-renal communication axis as well as a fundamental principle of this axis in the maintenance of salt homeostasis in vivo.

  View details for DOI 10.1172/JCI200318743

  View details for Web of Science ID 000186000300016

  View details for PubMedID 14561709

  View details for PubMedCentralID PMC213491

• Targeted inactivation of the mouse guanylin gene results in altered dynamics of colonic epithelial proliferation AMERICAN JOURNAL OF PATHOLOGY Steinbrecher, K. A., Wowk, S. A., Rudolph, J. A., Witte, D. P., Cohen, M. B. 2002; 161 (6): 2169-2178

  Abstract

  Heat-stable enterotoxin (STa), elaborated by enterotoxigenic Echerichia coli, is a worldwide cause of secretory diarrhea in infants and travelers. Both STa and guanylin, a peptide structurally similar to STa, increase intracellular cGMP levels after binding to the same intestinal receptor, guanylate cyclase C (GC-C). Distinct from its role as an intestinal secretagogue, guanylin may also have a role in intestinal proliferation, as guanylin expression is lost in intestinal adenomas. To determine the function of guanylin in intestinal epithelia, guanylin null mice were generated using a Cre/loxP-based targeting vector. Guanylin null mice grew normally, were fertile and showed no signs of malabsorption. However, the levels of cGMP in colonic mucosa of guanylin null mice were significantly reduced. The colonic epithelial cell migration rate was increased and increased numbers of colonocytes expressing proliferating cell nuclear antigen (PCNA) were present in crypts of guanylin null mice as well. The apoptotic index was similar in guanylin null mice and littermate controls. We conclude from these studies that loss of guanylin results in increased proliferation of colonic epithelia. We speculate that the increase in colonocyte number is related to decreased levels of cGMP and that this increase in proliferation plays a role in susceptibility to intestinal adenoma formation and/or progression.

  View details for DOI 10.1016/S0002-9440(10)64494-X

  View details for Web of Science ID 000179663400023

  View details for PubMedID 12466132

  View details for PubMedCentralID PMC1850912

• Coordinate upregulation of guanylin and uroguanylin expression by hypertonicity in HT29-18-N2 cells AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY Steinbrecher, K. A., Rudolph, J. A., Luo, G. J., Cohen, M. B. 2002; 283 (6): C1729-C1737

  Abstract

  Guanylin and uroguanylin are particulate guanylate cyclase-activating peptides that are secreted from the epithelia of the intestine, kidney, pancreas, and salivary gland. These peptides elicit chloride and bicarbonate secretion via the cystic fibrosis transmembrane conductance regulator. To test the hypothesis that hypertonicity mediates an increase in guanylin and uroguanylin mRNA, we subjected HT29-18-N2 to osmotic stress. Guanylin and uroguanylin RNA were increased substantially in the presence of hypertonicity but only with solutes that were relatively impermeable to the cell membrane. This hypertonicity-mediated increase was transcriptional and did not require protein synthesis. Herbimycin A and mitogen-activated protein kinase inhibitors SB-203580 and PD-98059 had no effect on basal or induced levels of guanylin or uroguanylin. Both staurosporine and prolonged exposure to phorbol ester reduced basal levels and completely blocked hypertonicity-related increases in guanylin or uroguanylin RNA. These data suggest that serine/theonine protein kinases, possibly protein kinase C (PKC), mediate the hypertonicity-associated increase in guanylin and uroguanylin RNA. We conclude that guanylin and uroguanylin are released in response to hypertonic stress and that regulation of these genes may be mediated by PKC isoforms.

  View details for DOI 10.1152/ajpcell.00010.2002

  View details for Web of Science ID 000179046400017

  View details for PubMedID 12388101

• Proguanylin secretion and the role of negative-feedback inhibition in a villous epithelial cell line AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY Rudolph, J. A., Hawkins, J. A., Cohen, M. B. 2002; 283 (3): G695-G702

  Abstract

  The mechanisms of proguanylin synthesis and secretion in the intestine are incompletely understood. We designed an in vitro model to study proguanylin secretion in a model of intestinal villous epithelial cells. The C2/bbe1 cell line, a differentiated subclone of Caco-2 cells, was used to examine the direction of proguanylin secretion and the potential for feedback regulation via activators of the guanylyl cyclase C signal transduction pathway. When cells were grown on Transwell inserts, proguanylin was secreted into the apical and basolateral media, consistent with other models of intestinal guanylin secretion. Proguanylin synthesis and secretion were not decreased on activation of guanylyl cyclase C-mediated chloride secretion, implying a regulatory system other than negative-feedback inhibition. These data describe the use of C2/bbe1 cells as a model for proguanylin secretion in villous epithelial cells and demonstrate their potential use for the study of the regulatory mechanisms governing proguanylin synthesis and secretion.

  View details for DOI 10.1152/ajpgi.00433.2001

  View details for Web of Science ID 000177502000025

  View details for PubMedID 12181185

• Shiga toxin-producing <i>E coli</i>:: Two tests are better than one JOURNAL OF PEDIATRICS Cohen, M. B. 2002; 141 (2): 155-156

  View details for DOI 10.1067/mpd.2002.126920

  View details for Web of Science ID 000177612500003

  View details for PubMedID 12183704

• Host-induced epidemic spread of the cholera bacterium NATURE Merrell, D. S., Butler, S. M., Qadri, F., Dolganov, N. A., Alam, A., Cohen, M. B., Calderwood, S. B., SCHOOLNIK, G. K., Camilli, A. 2002; 417 (6889): 642-645

  Abstract

  The factors that enhance the transmission of pathogens during epidemic spread are ill defined. Water-borne spread of the diarrhoeal disease cholera occurs rapidly in nature, whereas infection of human volunteers with bacteria grown in vitro is difficult in the absence of stomach acid buffering. It is unclear, however, whether stomach acidity is a principal factor contributing to epidemic spread. Here we report that characterization of Vibrio cholerae from human stools supports a model whereby human colonization creates a hyperinfectious bacterial state that is maintained after dissemination and that may contribute to epidemic spread of cholera. Transcriptional profiling of V. cholerae from stool samples revealed a unique physiological and behavioural state characterized by high expression levels of genes required for nutrient acquisition and motility, and low expression levels of genes required for bacterial chemotaxis.

  View details for Web of Science ID 000176001200046

  View details for PubMedID 12050664

  View details for PubMedCentralID PMC2776822

• Novel genes and functional relationships in the adult mouse gastrointestinal tract, identified by microarray analysis GASTROENTEROLOGY Bates, M. D., Erwin, C. R., Sanford, L. P., Wiginton, D., Bezerra, J. A., Schatzman, L. C., Jegga, A. G., Ley-Ebert, C., Williams, S. S., Steinbrecher, K. A., Warner, B. W., Cohen, M. B., Aronow, B. J. 2002; 122 (5): 1467-1482

  Abstract

  A genome-level understanding of the molecular basis of segmental gene expression along the anterior-posterior (A-P) axis of the mammalian gastrointestinal (GI) tract is lacking. We hypothesized that functional patterning along the A-P axis of the GI tract could be defined at the molecular level by analyzing expression profiles of large numbers of genes.Incyte GEM1 microarrays containing 8638 complementary DNAs (cDNAs) were used to define expression profiles in adult mouse stomach, duodenum, jejunum, ileum, cecum, proximal colon, and distal colon. Highly expressed cDNAs were classified based on segmental expression patterns and protein function.571 cDNAs were expressed 2-fold higher than reference in at least 1 GI tissue. Most of these genes displayed sharp segmental expression boundaries, the majority of which were at anatomically defined locations. Boundaries were particularly striking for genes encoding proteins that function in intermediary metabolism, transport, and cell-cell communication. Genes with distinctive expression profiles were compared with mouse and human genomic sequence for promoter analysis and gene discovery.The anatomically defined organs of the GI tract (stomach, small intestine, colon) can be distinguished based on a genome-level analysis of gene expression profiles. However, distinctions between various regions of the small intestine and colon are much less striking. We have identified novel genes not previously known to be expressed in the adult GI tract. Identification of genes coordinately regulated along the A-P axis provides a basis for new insights and gene discovery relevant to GI development, differentiation, function, and disease.

  View details for DOI 10.1053/gast.2002.32975

  View details for Web of Science ID 000175305500030

  View details for PubMedID 11984531

• Randomized, controlled human challenge study of the safety, immunogenicity, and protective efficacy of a single dose of Peru-15, a live attenuated oral cholera vaccine INFECTION AND IMMUNITY Cohen, M. B., Giannella, R. A., Bean, J., Taylor, D. N., Parker, S., Hoeper, A., Wowk, S., Hawkins, J., Kochi, S. K., Schiff, G., Killeen, K. P. 2002; 70 (4): 1965-1970

  Abstract

  Peru-15 is a live attenuated oral vaccine derived from a Vibrio cholerae O1 El Tor Inaba strain by a series of deletions and modifications, including deletion of the entire CT genetic element. Peru-15 is also a stable, motility-defective strain and is unable to recombine with homologous DNA. We wished to determine whether a single oral dose of Peru-15 was safe and immunogenic and whether it would provide significant protection against moderate and severe diarrhea in a randomized, double-blind, placebo-controlled human volunteer cholera challenge model. A total of 59 volunteers were randomly allocated to groups to receive either 2 x 10(8) CFU of reconstituted, lyophilized Peru-15 vaccine diluted in CeraVacx buffer or placebo (CeraVacx buffer alone). Approximately 3 months after vaccination, 36 of these volunteers were challenged with approximately 10(5) CFU of virulent V. cholerae O1 El Tor Inaba strain N16961, prepared from a standardized frozen inoculum. Among vaccinees, 98% showed at least a fourfold increase in vibriocidal antibody titers. After challenge, 5 (42%) of the 12 placebo recipients and none (0%) of the 24 vaccinees had moderate or severe diarrhea (> or = 3,000 g of diarrheal stool) (P = 0.002; protective efficacy, 100%; lower one-sided 95% confidence limit, 75%). A total of 7 (58%) of the 12 placebo recipients and 1 (4%) of the 24 vaccinees had any diarrhea (P < 0.001; protective efficacy, 93%; lower one-sided 95% confidence limit, 62%). The total number of diarrheal stools, weight of diarrheal stools, incidence of fever, and peak stool V. cholerae excretion among vaccinees were all significantly lower than in placebo recipients. Peru-15 is a well-tolerated and immunogenic oral cholera vaccine that affords protective efficacy against life-threatening cholera diarrhea in a human volunteer challenge model. This vaccine may therefore be a safe and effective tool to prevent cholera in travelers and is a strong candidate for further evaluation to prevent cholera in an area where cholera is endemic.

  View details for DOI 10.1128/IAI.70.4.1965-1970.2002

  View details for Web of Science ID 000174573200033

  View details for PubMedID 11895960

  View details for PubMedCentralID PMC127885

• Implementing an evidence-based acute gastroenteritis guideline at a children's hospital. The Joint Commission journal on quality improvement Perlstein, P. H., Lichtenstein, P., Cohen, M. B., Ruddy, R., Schoettker, P. J., Atherton, H. D., Kotagal, U. 2002; 28 (1): 20-30

  Abstract

  BACKGROUND: Guidelines for preventing and treating acute gastroenteritis (AGE) have generally not been incorporated into medical practice. An evidence-based clinical practice guideline was adapted from national guidelines to meet the practice styles characterizing care in southwestern Ohio and implemented at the Children's Hospital Medical Center (Cincinnati). Its efficacy was assessed in terms of emergency department (ED) encounters and admissions, mean and total hospital costs, and mean length of hospitalization.METHODS: Comparisons were made between patients seen during peak gastroenteritis months (December-May) before (fiscal year [FYs] 1994-1997) and after (FYs 1998 and 1999) guideline implementation. Data were extracted from hospital charts, clinical databases, and billing records.RESULTS: Following implementation, mean yearly ED encounters for AGE decreased 22% and mean yearly admissions decreased 33%. The percentage of admitted children with minor illness decreased (p = 0.002). Mean length of stay decreased 21% for children with minor illness (p = 0.0001) and 5% for others. Hydration status was noted in only 15% of ED charts examined but increased to 63% in FY 1998 and 86% in FY 1999 (p < 0.001). The proportion of admitted patients who advanced to a regular diet by discharge increased from 4.9% (FY 1997) to 23% (FY 1998) and 76% (FY 1999; p < 0.0001). Total inpatient days/year decreased by 43%. Mean hospital costs did not change significantly.DISCUSSION: Following implementation, fewer patients with AGE were seen in the ED and fewer were admitted to the hospital for care. Hospital stays were shorter, and children were more likely to resume their diets before discharge.

  View details for PubMedID 11787237

• Infectious diarrhea in children: Working group report of the First World Congress of Pediatric Gastroenterology, Hepatology, and Nutrition Davidson, G., Barnes, G., Bass, D., Cohen, M., Fasano, A., Fontaine, O., Guandalini, S. LIPPINCOTT WILLIAMS & WILKINS. 2002: S143-S150

  View details for DOI 10.1097/00005176-200208002-00012

  View details for Web of Science ID 000177571700012

  View details for PubMedID 12192183

• Research agenda for pediatric gastroenterology, hepatology and nutrition: secretion and diarrhea. Report of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition for the Children's Digestive Health and Nutrition Foundation. Journal of pediatric gastroenterology and nutrition Lencer, W. I., Barrett, K., Colgan, S., Cohen, M. B., Duggan, C. P., Kotelchuck, M., Rhoads, J. M. 2002; 35 Suppl 3: S246-9

  View details for DOI 10.1097/00005176-200210003-00004

  View details for PubMedID 12394359

• A human volunteer challenge model using frozen bacteria of the new epidemic serotype, <i>V</i>. <i>cholerae</i> O139 in Thai volunteers VACCINE Pitisuttithum, P., Cohen, M. B., Phonrat, B., Suthisarnsuntorn, U., Bussaratid, Desakorn, Phumratanaprapin, W., Singhasivanon, P., Looareesuwan, S., Schiff, G. M., Ivanoff, B., Lang, D. 2001; 20 (5-6): 920-925

  Abstract

  A total of 35 volunteers were recruited for an IRB-approved inpatient dose-escalation challenge. The goal was to identify a dose that produced an observed cholera attack rate > or =80% and an illness of sufficient severity during the defined study period such that the model would be useful for determining vaccine protection. Volunteers were challenged in groups of 5 with V. cholerae O139 that had been reconstituted immediately before use. Only 2 out of 5 volunteers who received the lowest dose (4.3 x 10(4) cfu) had diarrhea. As the inoculum size increased, the attack rate of diarrhea increased to 3-4 of 5 volunteers. At the highest dose tested, approximately 5 x 10(7) cfu, the attack rate was 73%. We recommend the use of frozen V. Cholera O139 in a human experimental challenge model to assess cholera vaccine efficacy (VE) in a cholera endemic area but with 4 days observation period before initiation of tetracycline to allow assessment of severity.

  View details for DOI 10.1016/S0264-410X(01)00381-4

  View details for Web of Science ID 000172871700033

  View details for PubMedID 11738758

• Increases in guanylin and uroguanylin in a mouse model of osmotic diarrhea are guanylate cyclase C-independent GASTROENTEROLOGY Steinbrecher, K. A., Mann, E. A., Giannella, R. A., Cohen, M. B. 2001; 121 (5): 1191-1202

  Abstract

  Guanylin and uroguanylin are peptide hormones that are homologous to the diarrhea-causing Escherichia coli enterotoxins. These secretagogues are released from the intestinal epithelia into the intestinal lumen and systemic circulation and bind to the receptor guanylate cyclase C (GC-C). We hypothesized that a hypertonic diet would result in osmotic diarrhea and cause a compensatory down-regulation of guanylin/uroguanylin.Gut-to-carcass weights were used to measure fluid accumulation in the intestine. Northern and/or Western analysis was used to determine the levels of guanylin, uroguanylin, and GC-C in mice with osmotic diarrhea.Wild-type mice fed a polyethylene glycol or lactose-based diet developed weight loss, diarrhea, and an increased gut-to-carcass ratio. Unexpectedly, 2 days on either diet resulted in increased guanylin/uroguanylin RNA and prohormone throughout the intestine, elevated uroguanylin RNA, and prohormone levels in the kidney and increased levels of circulating prouroguanylin. GC-C-deficient mice given the lactose diet reacted with higher gut-to-carcass ratios. Although they did not develop diarrhea, GC-C-sufficient and -deficient mice on the lactose diet responded with elevated levels of guanylin and uroguanylin RNA and protein. A polyethylene glycol drinking water solution resulted in diarrhea, higher gut-to-carcass ratios, and induction of guanylin and uroguanylin in both GC-C heterozygous and null animals.We conclude that this model of osmotic diarrhea results in a GC-C-independent increase in intestinal fluid accumulation, in levels of these peptide ligands in the epithelia of the intestine, and in prouroguanylin in the kidney and blood.

  View details for DOI 10.1053/gast.2001.28680

  View details for Web of Science ID 000171890100024

  View details for PubMedID 11677212

• Strategic planning for NASPGN JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Cohen, M. B., Demers, D., Colletti, R. B. 2001; 32 (1): 3-4

  View details for DOI 10.1097/00005176-200101000-00003

  View details for Web of Science ID 000166179200003

• A duodenum-specific enhancer regulates expression along three axes in the small intestine AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY Dusing, M. R., Brickner, A. G., Lowe, S. Y., Cohen, M. B., Wiginton, D. A. 2000; 279 (5): G1080-G1093

  Abstract

  Adenosine deaminase (ADA) is expressed at high levels in the epithelium of proximal small intestine. Transgenic mice were used to characterize the regulatory region governing this activation. A duodenum-specific enhancer is located in intron 2 of the human ADA gene at the central site among a cluster of seven DNase I-hypersensitive sites present in duodenal DNA. Flanking DNA, including the remaining hypersensitive sites, is required for consistent high-level enhancer function. The enhancer activates expression in a pattern identical to endogenous ADA along both the anterior-posterior axis of the small intestine and the crypt-villus differentiation axis of the intestinal epithelium. Timing of activation by the central enhancer mimics endogenous mouse ADA activation, occurring at 2-3 wk of age. However, two upstream DNA segments, one proximal and one distal, collaborate to change enhancer activation to a perinatal time point. Studies with duodenal nuclear extracts identified five distinct DNase I footprints within the enhancer. Protected regions encompass six putative binding sites for the transcription factor PDX-1, as well as proposed CDX, hepatocyte nuclear factor-4, and GATA-type sites.

  View details for DOI 10.1152/ajpgi.2000.279.5.G1080

  View details for Web of Science ID 000090062700028

  View details for PubMedID 11053006

• Expression of guanylin is downregulated in mouse and human intestinal adenomas BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Steinbrecher, K. A., Tuohy, T. M., Goss, K. H., Scott, M. C., Witte, D. P., Groden, J., Cohen, M. B. 2000; 273 (1): 225-230

  Abstract

  Guanylin is a pro-secretory hormone that is expressed in intestinal epithelia. Previously, we mapped the guanylin gene to mouse and human chromosomal regions containing multiple intestinal tumor-modifying loci. Here, we investigate whether guanylin expression is downregulated in precancerous human and mouse intestinal adenomas and whether diminished guanylin expression increases adenoma susceptibility in an animal model of intestinal cancer, the multiple intestinal neoplasia (Min) mouse. In situ hybridization analysis indicated diminished guanylin expression in both mouse and human adenomas. Northern analysis of mouse intestinal tissues showed strain-specific levels of guanylin expression but no correlation with the resistance or susceptibility of each strain to adenoma formation. Similarly, cDNA sequence analysis indicated no inactivating mutations or polymorphisms common to either the high or low adenoma-risk groups. Nonetheless, we have shown that significant loss of guanylin RNA in adenomas of mouse and human is a marker of intestinal epithelial cell transformation.

  View details for DOI 10.1006/bbrc.2000.2917

  View details for Web of Science ID 000087932800040

  View details for PubMedID 10873591

• The uroguanylin gene (<i>Guca1b</i>) is linked to guanylin (<i>Guca2</i>) on mouse chromosome 4 (vol 45, pg 348, 1997) GENOMICS Whitaker, T. L., Steinbrecher, K. A., Copeland, N. G., Gilbert, D. J., Jenkins, N. A., Cohen, M. B. 2000; 66 (1): 122

  View details for DOI 10.1006/geno.2000.6182

  View details for Web of Science ID 000087261500017

• The Shwachman Award of the North American Society for Pediatric Gastroenterology and Nutrition, 1999: Presentation JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Cohen, M. B. 2000; 30 (4): 355-358

  View details for DOI 10.1097/00005176-200004000-00001

  View details for Web of Science ID 000086828000001

  View details for PubMedID 10917784

• Gastrointestinal infections in children CURRENT OPINION IN GASTROENTEROLOGY Ee, L. C., Cohen, M. B. 2000; 16 (1): 40-44

  Abstract

  New pathogens that cause gastroenteritis in children are being recognized. Even well-recognized pathogens, such as Clostridium difficile, may require more extensive testing than was previously thought necessary. Several new tests have emerged that allow for faster identification of these pathogens so that same-day results may be possible. Probiotic therapy has emerged as a novel strategy for the treatment of gastroenteritis. New vaccines against both viral and bacterial causes of gastroenteritis are being developed. The most exciting recent advance in vaccine development may be the creation of edible vaccines.

  View details for DOI 10.1097/00001574-200001000-00007

  View details for Web of Science ID 000084412500007

  View details for PubMedID 17024014

• Validation and characterization of a human volunteer challenge model for cholera by using frozen bacteria of the new <i>Vibrio cholerae</i> epidemic serotype, O139 INFECTION AND IMMUNITY Cohen, M. B., Giannella, R. A., Losonsky, G. A., Lang, D. R., Parker, S., Hawkins, J. A., Gunther, C., Schiff, G. A. 1999; 67 (12): 6346-6349

  Abstract

  Until recently, all epidemic strains of Vibrio cholerae were of the O1 serotype. Current epidemics have also been caused by a new serotype, Vibrio cholerae O139. Although the pathogenesis and clinical features of O139 cholera are similar to those of O1 cholera, immunity to serotype O1 does not confer immunity to serotype O139. Therefore, prior to beginning vaccine efficacy studies, we sought to validate the use of a large standardized frozen inoculum of virulent V. cholerae O139 4260B for use in a human volunteer challenge model. Healthy volunteers (n = 25) were recruited for an Internal Review Board-approved inpatient dose-escalation challenge. Our goal was to identify a dose at which the cholera attack rate and the geometric mean purge were sufficient for determining vaccine efficacy against moderate and severe disease. At a dose of 10(5) CFU, 8 of 10 volunteers experienced purging and had a positive stool culture for V. cholerae. However, at this dose, the geometric mean stool volume of 2,175 g was insufficient by study criteria. At a dose of 10(6) CFU, 14 of 15 volunteers experienced purging, with a geometric mean stool volume of 5,621 g. Disease severity was significantly greater in volunteers with blood group O than those with non-O blood types (10,353 g versus 3,555 g, P < 0.001). Following challenge, all volunteers demonstrated a significant rise in antitoxin antibodies but the serum vibriocidal titer was attenuated compared to that seen after challenge with an O1 strain. This model provides a reproducible illness of sufficient severity for testing the efficacies of new O139 or combined O1-O139 vaccines.

  View details for Web of Science ID 000083768000018

  View details for PubMedID 10569748

  View details for PubMedCentralID PMC97040

• Randomized, double-blind, placebo-controlled, multicentered trial of the efficacy of a single dose of live oral cholera vaccine CVD 103-HgR in preventing cholera following challenge with <i>Vibrio cholerae</i> O1 El Tor Inaba three months after vaccination INFECTION AND IMMUNITY Tacket, C. O., Cohen, M. B., Wasserman, S. S., Losonsky, G., Livio, S., Kotloff, K., Edelman, R., Kaper, J. B., Cryz, S. J., Giannella, R. A., Schiff, G., Levine, M. M. 1999; 67 (12): 6341-6345

  Abstract

  CVD 103-HgR is a live oral cholera vaccine strain constructed by deleting 94% of the gene for the enzymatically active A subunit of cholera toxin from classical Inaba Vibrio cholerae O1 569B; the strain also contains a mercury resistance gene as an identifying marker. This vaccine was well tolerated and immunogenic in double-blind, controlled studies and was protective in open-label studies of volunteers challenged with V. cholerae O1. A randomized, double-blind, placebo-controlled, multicenter study of vaccine efficacy was designed to test longer-term protection of CVD 103-HgR against moderate and severe El Tor cholera in U.S. volunteers. A total of 85 volunteers (50 at the University of Maryland and 35 at Children's Hospital Medical Center/University of Cincinnati) were recruited for vaccination and challenge with wild-type V. cholerae El Tor Inaba. Volunteers were randomized in a double-blind manner to receive, with buffer, a single oral dose of either CVD 103-HgR (2 x 10(8) to 8 x 10(8) CFU) or placebo (killed E. coli K-12). About 3 months after immunization, 51 of these volunteers were orally challenged with 10(5) CFU of virulent V. cholerae O1 El Tor Inaba strain N16961, prepared from a standardized frozen inoculum. Ninety-one percent of the vaccinees had a >/=4-fold rise in serum vibriocidal antibodies after vaccination. After challenge, 9 (39%) of the 23 placebo recipients and 1 (4%) of the 28 vaccinees had moderate or severe diarrhea (>/=3-liter diarrheal stool) (P < 0.01; protective efficacy, 91%). A total of 21 (91%) of 23 placebo recipients and 5 (18%) of 28 vaccinees had any diarrhea (P < 0.001; protective efficacy, 80%). Peak stool V. cholerae excretion among placebo recipients was 1.1 x 10(7) CFU/g and among vaccinees was 4.9 x 10(2) CFU/g (P < 0.001). This vaccine could therefore be a safe and effective tool to prevent cholera in travelers.

  View details for Web of Science ID 000083768000017

  View details for PubMedID 10569747

  View details for PubMedCentralID PMC97039

• NASPGN guidelines for training in pediatric gastroenterology JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Rudolph, C. D., Winter, H. S., NASPGN Executive Council, NASPGN Training Educ Comm 1999; 29: S1-S26

  View details for DOI 10.1097/00005176-199911001-00001

  View details for Web of Science ID 000087032700001

  View details for PubMedID 10554139

• Food-borne and water-borne infections and the gastroenterologist JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Tarr, P. I., Cohen, M. B., Donowitz, M. 1999; 29 (3): 237-238

  View details for DOI 10.1097/00005176-199909000-00002

  View details for Web of Science ID 000082043300002

  View details for PubMedID 10467986

• New causes and treatments for infectious diarrhea in children. Current gastroenterology reports Rudolph, J. A., Cohen, M. B. 1999; 1 (3): 238-44

  Abstract

  Infectious diarrhea is a universal and important health problem in the pediatric population. An expanding number of potential viral, bacterial, and parasitic pathogens have been associated with diarrheal disease. However, the epidemiologic association of a microorganism with diarrhea is only one step in the process of identifying new pathogens. Once the virulence mechanisms of these organisms are elucidated, a causal relationship can be more readily defined. This article reviews the etiologic agents of diarrhea in the pediatric population and focuses on the newer treatment and prevention modalities, including probiotics and vaccinations, which are used increasingly to combat these diseases.

  View details for DOI 10.1007/s11894-999-0041-3

  View details for PubMedID 10980956

• Controversies in pediatric inflammatory bowel disease INFLAMMATORY BOWEL DISEASES Cohen, M. B., Seidman, E., Winter, H., Colletti, R. B., Kirschner, B., Balistreri, W. F., Grand, R. J. 1998; 4 (3): 203-227

  View details for DOI 10.1097/00054725-199808000-00005

  View details for Web of Science ID 000075542800005

• Validation of a volunteer model of cholera with frozen bacteria as the challenge INFECTION AND IMMUNITY Sack, D. A., Tacket, C. O., Cohen, M. B., Sack, R. B., Losonsky, G. A., Shimko, J., Nataro, J. P., Edelman, R., Levine, M. M., Giannella, R. A., Schiff, G., Lang, D. 1998; 66 (5): 1968-1972

  Abstract

  To evaluate a standardized inoculum of Vibrio cholerae for volunteer challenge studies, 40 healthy adult volunteers were challenged at three different institutions with a standard inoculum prepared directly from vials of frozen, virulent, El Tor Inaba V. cholerae N16961, with no further incubation. Groups of 5 volunteers, with each group including 2 volunteers with blood group O, were given a dose of 10(5) CFU, and 34 of the 40 volunteers developed diarrhea (mean incubation time, 28 h). Transient fevers occurred in 15 (37.5%) of the volunteers. V. cholerae was excreted by 36 of 40 volunteers. Five additional volunteers received 10(4) CFU, and four developed diarrhea but with a lower average purging rate than required for the model. Of the 40 volunteers, 37 developed rises in their vibriocidal and antitoxin titers similar to those in previous groups challenged with freshly harvested bacteria. We conclude that challenge with frozen bacteria results in a reproducible illness similar to that induced by freshly harvested bacteria. Use of this model should minimize differences in attack rates or severity when groups are challenged at different times and in different institutions.

  View details for DOI 10.1128/IAI.66.5.1968-1972.1998

  View details for Web of Science ID 000073413100023

  View details for PubMedID 9573077

  View details for PubMedCentralID PMC108151

• <i>Escherichia coli</i> O157:H7:: Assessing and minimizing the risk from farm to fork JOURNAL OF PEDIATRICS Cohen, M. B. 1998; 132 (5): 756-757

  View details for DOI 10.1016/S0022-3476(98)70296-3

  View details for Web of Science ID 000073610400002

  View details for PubMedID 9602178

• Exacerbation of autoimmune hepatitis: Another hepatotoxic effect of pemoline therapy PEDIATRICS Hochman, J. A., Woodard, S. A., Cohen, M. B. 1998; 101 (1): 106-108

  View details for DOI 10.1542/peds.101.1.106

  View details for Web of Science ID 000071331400032

  View details for PubMedID 9417161

• Guanylin mRNA expression in human intestine and colorectal adenocarcinoma LABORATORY INVESTIGATION Cohen, M. B., Hawkins, J. A., Witte, D. P. 1998; 78 (1): 101-108

  Abstract

  Guanylin is a mammalian peptide ligand that binds to the enterocyte receptor guanylyl cyclase C and mediates Cl- and HCO3- efflux via the cystic fibrosis transmembrane conductance regulator. To identify the regional localization of guanylin mRNA in the human intestine, we performed in situ hybridization using a guanylin-specific riboprobe. The pattern of guanylin mRNA distribution is complex and includes all epithelial lineages at various points along the duodenal-to-colonic axis. Guanylin mRNA expression is most prominent in the distal small intestine and colon. In the normal colon, guanylin mRNA is robustly expressed in superficial epithelial cells; in colorectal adenocarcinoma, however, guanylin mRNA expression is absent. Guanylin mRNA is detectable in several intestinal tumor cell lines, although at much lower levels than those seen in the human intestine. The pattern of guanylin expression is consistent with the possibility of region-specific functions for guanylin within the human intestine. Furthermore, the diminished expression of guanylin mRNA in adenocarcinoma of the colon and in colon cancer cell lines, along with the chromosomal localization of guanylin to the tumor modifier region 1p34-35, raises the possibility that loss of guanylin activity leads to or is a result of adenocarcinoma formation.

  View details for Web of Science ID 000071771200010

  View details for PubMedID 9461126

• The uroguanylin gene (Guca1b) is linked to guanylin (Guca2) on mouse chromosome 4 GENOMICS Whitaker, T. L., Steinbrecher, K. A., Copeland, N. G., Gilbert, D. J., Jenkins, N. A., Cohen, M. B. 1997; 45 (2): 348-354

  Abstract

  Uroguanylin is an endogenous ligand of the intestinal receptor guanylate cyclase-C (GC-C). Both uroguanylin and the related peptide ligand guanylin bind to GC-C and stimulate an increase in cyclic GMP, inducing chloride secretion via the cystic fibrosis transmembrane conductance regulator. We describe the cloning of the complete mouse uroguanylin gene (Guca1b) and show that Guca1b is tightly linked to the mouse guanylin gene on chromosome 4. The two genes are structurally similar, being composed of three short exons; the uroguanylin gene spans 2.4 kb and the guanylin gene spans 1.7 kb. Uroguanylin mRNA is most prominent in proximal small intestine, whereas guanylin mRNA is predominantly expressed in distal small intestine and colon. The upstream promoter sequence of the mouse uroguanylin gene contains a canonical TATA element at the site of transcription initiation and consensus binding sites for several known transcription factors, including HNF-1 and Sp1 within the first 1 kb. Although the gene structure and coding sequences of uroguanylin and guanylin are similar, the 5' flanking sequences and patterns of expression of these two genes in the intestine are different. It is likely that uroguanylin and guanylin represent gene duplications that have evolved to allow overlapping and complementary patterns of expression in the intestine.

  View details for DOI 10.1006/geno.1997.4942

  View details for Web of Science ID A1997YC79200016

  View details for PubMedID 9344659

• Uroguanylin and guanylin: Distinct but overlapping patterns of messenger RNA expression in mouse intestine GASTROENTEROLOGY Whitaker, T. L., Witte, D. P., Scott, M. C., Cohen, M. B. 1997; 113 (3): 1000-1006

  Abstract

  Uroguanylin and guanylin, endogenous ligands of the guanylate cyclase C receptor, are presumed to mediate fluid and electrolyte secretion in the intestine. The aim of this study was to characterize the expression patterns of uroguanylin and guanylin messenger RNA (mRNA) in the mouse intestine.A mouse uroguanylin complementary DNA was amplified from a partial genomic clone, and Northern analyses and in situ hybridization were performed to localize guanylin and uroguanylin mRNA along the duodenal-colonic and crypt-villus axes.Uroguanylin mRNA was expressed throughout the mouse intestine and also in the kidney. Signal intensity was greatest in the small intestine for uroguanylin and in the distal small intestine and colon for guanylin. In situ hybridization showed uroguanylin mRNA localized predominantly in intestinal villi and the corticomedullary junction of the kidney, whereas guanylin mRNA was localized in both crypts and villi in the small intestine and to superficial epithelial cells in the colon.Mouse uroguanylin mRNA expression is discrete from guanylin expression in the intestine. The patterns of distribution in the intestine and the known pH optima of these ligands suggest a complementary role for these secretagogues.

  View details for DOI 10.1016/S0016-5085(97)70197-5

  View details for Web of Science ID A1997XW96000038

  View details for PubMedID 9287995

• The heat-stable enterotoxin-guanylin receptor is expressed in rat hepatocytes and in a rat hepatoma (H-35) cell line JOURNAL OF RECEPTOR AND SIGNAL TRANSDUCTION RESEARCH Balint, J. P., Kosiba, J. L., Cohen, M. B. 1997; 17 (4): 609-630

  Abstract

  Guanylyl cyclase C (GC-C) is an intestinal transmembrane receptor which binds both guanylin, an endogenous ligand, and Escherichia coli heat-stable enterotoxin (STa) resulting in 5'-cyclic guanosine monophosphate (cGMP) accumulation and chloride secretion. In the adult rat, there is a high basal level of GC-C expression in the intestine, but not in the liver. Increased expression of GC-C in the rat liver has been demonstrated during the perinatal period as well as with liver regeneration and during an acute phase response. The aim of this study was to identify and utilize cell culture models to further characterize the expression of GC-C in the liver.STa binding, STa-stimulated cGMP accumulation, and GC-C RNA expression by Northern analysis were determined in primary cultures of rat hepatocytes and H-35 cells, a rat hepatoma cell line, following treatment with dexamethasone and/or interleukin-6 (IL-6).In rat hepatocytes treated with the combination of dexamethasone and IL-6, there was an increase in STa binding, STa-stimulated cGMP accumulation, and GC-C RNA expression as compared to untreated cells. In H-35 cells treated with dexamethasone alone, there was an increase in STa binding, STa-stimulated cGMP accumulation, and GC-C RNA expression as compared to untreated cells.Primary cultures of rat hepatocytes and H-35 cells can be utilized to further study upregulation of GC-C in the hepatocyte. The expression of this receptor in hepatocytes, combined with the recent demonstration of circulating guanylin, is consistent with a functional role for GC-C in the liver.

  View details for DOI 10.3109/10799899709039153

  View details for Web of Science ID A1997XH55900004

  View details for PubMedID 9220371

• Outpatient liver biopsy in children: A medical position statement of the north American society for pediatric gastroenterology and nutrition JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Fox, V. L., Cohen, M. B., Whitington, P. F., Colletti, R. B. 1996; 23 (3): 213-216

  View details for DOI 10.1097/00005176-199610000-00002

  View details for Web of Science ID A1996VG92400002

  View details for PubMedID 8890068

• Diagnosis of cytomegalovirus infection in pediatric Menetrier's disease by in situ hybridization JOURNAL OF CLINICAL MICROBIOLOGY Hochman, J. A., Witte, D. P., Cohen, M. B. 1996; 34 (10): 2588-2589

  Abstract

  A previously healthy 7-year-old boy presented with a protein-losing enteropathy secondary to a hypertrophic gastropathy. The diagnosis of cytomegalovirus (CMV) infection was established by detection of CMV inclusion bodies in gastric biopsy samples and by hybridization with a CMV probe. This report further strengthens the association between CMV and pediatric Menetrier's disease.

  View details for DOI 10.1128/JCM.34.10.2588-2589.1996

  View details for Web of Science ID A1996VK78700049

  View details for PubMedID 8880525

  View details for PubMedCentralID PMC229324

• Infectious gastroenterocolitides in children - An update on emerging pathogens PEDIATRIC CLINICS OF NORTH AMERICA Sherman, P. M., Petric, M., Cohen, M. B. 1996; 43 (2): 391-+

  Abstract

  The recognition that bacterial infections induce signal transduction responses in infected epithelial cells also provides new avenues to consider as novel forms of therapy. For example, the chemokine interleukin-8, which attracts neutrophils to sites of mucosal infection, is produced by epithelial cells of gastric and intestinal origin in response to bacterial infection. Inhibitors of chemokine production or inhibition of the biologic effects of neutrophil chemoattractants have the potential to reduce both mucosal inflammatory responses and the attendant clinical sequelae. Eukaryotic cells also respond to infection with elevations in cytosolic second messengers, including inositol triphosphate (IP3) and calcium ([Ca2+]i). In intestinal epithelium, these second messengers can mediate the diarrheal response to infection. Calcium/calmodulin inhibitors may have a beneficial effect in treating those gastrointestinal infections mediated through changes in the level of cytosolic free calcium. DuPont and colleagues showed, for example, that oral therapy with zaldaride maleate relieves symptoms of disease and shortens the duration of diarrhea in travelers with ETEC-induced diarrhea. Evaluation of additional signal transduction responses to microbial infections should provide both new insights into the pathogenesis of gastrointestinal infectious diseases and novel approaches to consider for the prevention and therapy for these human illnesses.

  View details for DOI 10.1016/S0031-3955(05)70412-0

  View details for Web of Science ID A1996UF54200006

  View details for PubMedID 8614607

  View details for PubMedCentralID PMC7141033

• Escherichia coli O157:H7 infections: a frequent cause of bloody diarrhea and the hemolytic-uremic syndrome. Advances in pediatrics Cohen, M. B. 1996; 43: 171-207

  View details for PubMedID 8794177

• WHEREFORE ART THOU GUANYLIN GASTROENTEROLOGY COHEN, M. B. 1995; 109 (6): 2039-2042

  View details for DOI 10.1016/0016-5085(95)90777-7

  View details for Web of Science ID A1995TG75400042

  View details for PubMedID 7498675

• A selective advantage for cystic fibrosis carriers. Journal of pediatric gastroenterology and nutrition Lewis, L. G., Cohen, M. B. 1995; 21 (1): 117-8

  View details for DOI 10.1097/00005176-199507000-00024

  View details for PubMedID 8576805

• USE OF A SINGLE SOLUTION FOR ORAL REHYDRATION AND MAINTENANCE THERAPY OF INFANTS WITH DIARRHEA AND MILD-TO-MODERATE DEHYDRATION PEDIATRICS COHEN, M. B., MEZOFF, A. G., LANEY, D. W., BEZERRA, J. A., BEANE, B. M., DRAZNER, D., BAKER, R., MORAN 1995; 95 (5): 639-645

  Abstract

  To compare the efficacy of two commonly used solutions in the rehydration of infants with mild to moderate dehydration caused by acute diarrhea in the United States.Double-blind, parallel-group, randomized study performed at Children's Hospital Medical Center.Sixty infant boys (< or = 2 years old), with mild (< or = 5%) or moderate (6 to 9%) dehydration caused by acute diarrhea of less than 1 week's duration were included in the study.Infants were randomly assigned to receive treatment with either a glucose-based oral rehydration solution (ORS) (Pedialyte, Ross Laboratories, Columbus, OH) or a rice syrup solids-based ORS (Infalyte, Mead Johnson Nutritional Group, Evansville, IN). After rehydration was achieved, patients entered a maintenance phase during which, in addition to a maintenance ORS, breast milk or a soy-based formula was offered; infants older than 1 year were also given a lactose-free diet.Rehydration was judged clinically. Infants remained on a metabolic bed during the study in to separate and quantitate urine and stool output. Therefore, in addition to clinical outcome, we compared intake, output and apparent absorption and retention of fluid, sodium, and potassium between groups.All patients were successfully rehydrated using an ORS without the use of intravenous fluids. No differences were detected between treatment groups in time to rehydration, percentage of weight gain after rehydration, consumption of ORS to achieve rehydration, or stool output. However, the apparent sodium absorption (net intake less fecal output) was greater in the Infalyte group than the Pedialyte group during the first 24 hours.The two maintenance oral electrolyte solutions (Pedialyte and Infalyte) most commonly used in the United States are effective as rehydration solutions for infants with mild to moderate dehydration. We speculate that a strategy for oral rehydration therapy in the United States, based on the use of a single solution during the rehydration and maintenance phase, might gain additional acceptance by practicing pediatricians and family physicians.

  View details for Web of Science ID A1995QW47900004

  View details for PubMedID 7724298

• IMMUNOHISTOCHEMICAL LOCALIZATION OF GUANYLIN IN THE RAT SMALL-INTESTINE AND COLON BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS COHEN, M. B., WITTE, D. P., HAWKINS, J. A., CURRIE, M. G. 1995; 209 (3): 803-808

  Abstract

  Guanylin is an endogenous mammalian ligand which binds to guanylate cyclase C (GC-C), the Escherichia coli heat-stable enterotoxin receptor. This interaction results in intestinal Cl- and fluid secretion, which is largely, if not exclusively, mediated through the cystic fibrosis transmembrane regulator (CFTR). Using in situ hybridization, we have previously localized guanylin mRNA to villus epithelial cells of the rat small intestine and to superficial epithelial cells of the rat colon. In the present study, we demonstrate immunoreactive guanylin in a subpopulation of goblet cells in the rat jejunum and ileum. In the colon, there was immunostaining of superficial epithelial cells and goblet cells. The immunohistochemical localization of guanylin parallels the observed distribution of guanylin mRNA. Localization of guanylin in goblet cells leads us to speculate that an in vivo function of guanylin regulated, CFTR-mediated Cl- secretion is to hydrate intestinal mucin.

  View details for DOI 10.1006/bbrc.1995.1571

  View details for Web of Science ID A1995QV60200004

  View details for PubMedID 7733972

• MAPPING OF GUANYLIN TO MURINE CHROMOSOME-4 AND HUMAN-CHROMOSOME 1P34-P35 GENOMICS SCIAKY, D., JENKINS, N. A., GILBERT, D. J., COPELAND, N. G., SONODA, G., TESTA, COHEN, M. B. 1995; 26 (2): 427-429

  View details for DOI 10.1016/0888-7543(95)80238-H

  View details for Web of Science ID A1995QR15600041

  View details for PubMedID 7601480

• COLONIC INFECTIONS, INCLUDING THOSE IN THE IMMUNOSUPPRESSED HOST CURRENT OPINION IN GASTROENTEROLOGY LEWIS, L. G., COHEN, M. B. 1995; 11 (1): 22-28

  View details for DOI 10.1097/00001574-199501000-00006

  View details for Web of Science ID A1995QB07800005

• GENOMIC SEQUENCE OF THE MURINE GUANYLIN GENE GENOMICS SCIAKY, D., KOSIBA, J. L., COHEN, M. B. 1994; 24 (3): 583-587

  Abstract

  Guanylin, a 15-amino-acid peptide, is an endogenous ligand of the intestinal receptor guanylate cyclase-C. After binding to this receptor, guanylin increases the intracellular concentration of cyclic GMP and induces chloride secretion. We have isolated a genomic clone containing the entire murine guanylin gene. The guanylin gene is composed of three exons that span 1700 bp. The first 133 nucleotides of upstream promoter sequence lack the canonical TATA, CAAT, and SP1 elements. Guanylin transcription is nearly exclusively limited to the intestine, and the presence of guanylin mRNA is greatest in the distal colon and ileum. Therefore, characterization of the guanylin promoter is likely to provide another paradigm for intestine-specific gene regulation.

  View details for DOI 10.1006/geno.1994.1670

  View details for Web of Science ID A1994PZ98500024

  View details for PubMedID 7713512

• DIARRHEAL DISEASE - ESTABLISHED PATHOGENS, NEW PATHOGENS, AND PROGRESS IN VACCINE DEVELOPMENT GASTROENTEROLOGY CLINICS OF NORTH AMERICA DELLERT, S. F., COHEN, M. B. 1994; 23 (4): 637-654

  Abstract

  Although much progress has been made in reducing the morbidity and mortality of infectious diarrhea through the use of oral rehydration, progress in preventive measures, such as vaccine development, has been slow. Despite the plethora of candidate vaccines developed, there has not been an effective vaccine ready for general use, particularly in developing countries, during the past decade, perhaps in part because of the as-yet-undefined pathophysiology of many of these pathogens, as well as the complexity of the gastrointestinal immune system. It is hoped that more rapid progress will be made during the next decade as our understanding of these factors increases.

  View details for Web of Science ID A1994PY04900003

  View details for PubMedID 7698825

• GUANYLIN MESSENGER-RNA IS EXPRESSED IN VILLOUS ENTEROCYTES OF THE RAT SMALL-INTESTINE AND SUPERFICIAL EPITHELIA OF THE RAT COLON BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS LEWIS, L. G., WITTE, D. P., LANEY, D. W., CURRIE, M. G., COHEN, M. B. 1993; 196 (2): 553-560

  Abstract

  Guanylin, and endogenous ligand for the Escherichia coli heat-stable enterotoxin receptor, is a recently characterized intestinal peptide. To understand the possible physiologic function of guanylin, we examined the cellular location of guanylin mRNA expression in the rat intestine. Intestinal cells were sequentially isolated from villous tip to crypt in rat jejunum and ileum. Northern blots of total RNA identified a single 0.65 kb guanylin transcript predominantly in the villous cell fractions. In situ hybridization studies demonstrated maximal signal intensity in villous cells in rat ileum and surface epithelial cells in the colon. In the ileum, the signal was nonuniform in distribution in the surface epithelial cells, with focal areas of intense signal in clusters of columnar absorptive cells. In both colon and ileum, signal intensity was near background level in deep crypt cells, lamina propria, and muscularis.

  View details for DOI 10.1006/bbrc.1993.2285

  View details for Web of Science ID A1993MG11400008

  View details for PubMedID 8240327

• TRAVELERS DIARRHEA AMERICAN FAMILY PHYSICIAN HECK, J. E., COHEN, M. B. 1993; 48 (5): 793-800

  Abstract

  Traveler's diarrhea is the most common health problem in persons who visit developing countries. Dietary precautions are the mainstay of prevention. Since bacteria are responsible for 50 to 80 percent of cases of traveler's diarrhea, antibiotics are the drugs of choice for empiric therapy. Because bacteria are becoming increasingly resistant to trimethoprim-sulfamethoxazole and doxycycline, newer antibiotics, especially the fluoroquinolones, should be considered as first-line therapy. Antimotility agents may help reduce symptoms, but they should not be given to patients who have fever or bloody diarrhea. Antibiotic prophylaxis is recommended for certain high-risk individuals.

  View details for Web of Science ID A1993MA61200015

  View details for PubMedID 8213410

• Gastrointestinal infection in children. Current opinion in pediatrics Lewis, L. G., Cohen, M. B. 1993; 5 (5): 573-9

  Abstract

  Infections of the gastrointestinal tract remain an important cause of childhood morbidity and mortality worldwide. A number of pertinent articles have appeared in the past year, advancing our understanding of 1) Helicobacter pylori-induced gastroduodenal disease, 2) Escherichia coli O157:H7-mediated diarrhea, and 3) newer gastrointestinal parasites that cause diarrhea. These are the topics of review.

  View details for DOI 10.1097/00008480-199310000-00010

  View details for PubMedID 8287081

• APPROACH TO THE PEDIATRIC-PATIENT WITH DIARRHEA GASTROENTEROLOGY CLINICS OF NORTH AMERICA LANEY, D. W., COHEN, M. B. 1993; 22 (3): 499-516

  Abstract

  Numerous viral, bacterial, and parasitic pathogens are known to cause diarrheal illnesses with increased frequency in children. Oral rehydration can be used to treat and prevent dehydration, the major sequela of diarrhea in children. The impact of diarrhea on nutrition may also be reduced through the rapid restoration of a normal, age-appropriate diet. Most diarrheal illnesses are acute and self-limited; however, increased knowledge of persistent diarrheal syndromes in children may lead to prompt recognition and diagnosis in children with diarrhea lasting more than 2 weeks.

  View details for Web of Science ID A1993LW82300003

  View details for PubMedID 8406727

• MEDICAID COVERAGE OF ORAL REHYDRATION SOLUTIONS NEW ENGLAND JOURNAL OF MEDICINE COHEN, M. B., HARDIN, J. 1993; 329 (3): 211

  View details for DOI 10.1056/NEJM199307153290319

  View details for Web of Science ID A1993LL46000027

  View details for PubMedID 8515800

• RECEPTORS FOR ESCHERICHIA-COLI HEAT-STABLE ENTEROTOXIN IN HUMAN INTESTINE AND IN A HUMAN INTESTINAL-CELL LINE (CACO-2) JOURNAL OF CELLULAR PHYSIOLOGY COHEN, M. B., JENSEN, N. J., HAWKINS, J. A., MANN, E. A., THOMPSON, M. R., LENTZE, M. J., GIANNELLA, R. A. 1993; 156 (1): 138-144

  Abstract

  Escherichia coli heat stable enterotoxin (STa) and the newly identified endogenous ligand guanylin bind to an intestinal receptor and activate membrane bound guanylate cyclase. We compared STa binding and affinity crosslinking of STa receptors in human small intestine to those in the Caco-2 human colon carcinoma cell line. STa had similar kinetics of binding in human intestinal and Caco-2 brush border membranes. In both human intestine and Caco-2 brush border membranes, multiple specifically radiolabeled bands, including a 140-165 kDa band, were identified by affinity crosslinking. However, in human intestine the most prominent autoradiographic species was a 60 kDa band. A 60 kDa protein was also specifically immunoprecipitated from solubilized human brush border membranes using antisera raised against a cloned STa receptor fusion protein. Our observations of multiple crosslinked proteins in human intestine and Caco-2 cells could be explained by the existence of several members of a family of STa receptors and/or the existence of smaller STa binding proteins generated by the protease cleavage of a larger complete STa receptor.

  View details for DOI 10.1002/jcp.1041560119

  View details for Web of Science ID A1993LK26800018

  View details for PubMedID 8100232

• COLONIZATION BY ENTEROAGGREGATIVE ESCHERICHIA-COLI IN TRAVELERS WITH AND WITHOUT DIARRHEA JOURNAL OF CLINICAL MICROBIOLOGY COHEN, M. B., HAWKINS, J. A., WECKBACH, L. S., STANECK, J. L., LEVINE, M. M., HECK, J. E. 1993; 31 (2): 351-353

  Abstract

  Enteroaggregative Escherichia coli (EAggEC) has been found to be associated with pediatric diarrhea in developing countries. In order to determine the role of EAggEC as an agent of traveler's diarrhea, we used a sensitive and specific DNA probe for EAggEC to screen bacterial colony blots from 278 volunteers before and after travel. Colonization with EAggEC was infrequent (2.5%) prior to travel but rose to 27 to 33% after travel in volunteers who took either placebo or trimethoprim-sulfamethoxazole. Travelers who took trimethoprimsulfamethoxazole were colonized with organisms that were uniformly resistant to that antimicrobial agent; when volunteers received ciprofloxacin, colonization with EAggEC was prevented (2.0%). Although colonization rates were high in the placebo and trimethoprim-sulfamethoxazole groups, only a minority of travelers who were colonized with EAggEC experienced diarrhea. On the basis of our data, we suggest that colonization with EAggEC alone is not sufficient to cause traveler's diarrhea.

  View details for DOI 10.1128/JCM.31.2.351-353.1993

  View details for Web of Science ID A1993KH75100034

  View details for PubMedID 8432822

  View details for PubMedCentralID PMC262763

• INTRACRANIAL HEMORRHAGE DUE TO VITAMIN-K DEFICIENCY IN BREAST-FED INFANTS WITH CHOLESTASIS JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION BANCROFT, J., COHEN, M. B. 1993; 16 (1): 78-80

  View details for DOI 10.1097/00005176-199301000-00015

  View details for Web of Science ID A1993KD20300016

  View details for PubMedID 8433245

• COMPARISON OF RECEPTORS FOR ESCHERICHIA-COLI HEAT-STABLE ENTEROTOXIN - NOVEL RECEPTOR PRESENT IN IEC-6 CELLS AMERICAN JOURNAL OF PHYSIOLOGY MANN, E. A., COHEN, M. B., GIANNELLA, R. A. 1993; 264 (1): G172-G178

  Abstract

  Enterotoxigenic Escherichia coli elaborate a heat-stable enterotoxin that causes diarrhea in humans and animals. The primary event in the diarrheal cascade is the binding of this enterotoxin to specific receptors on enterocytes and activation of guanylyl cyclase. Two intestinal cell lines, Caco-2 and IEC-6, were tested for the presence of these receptors. Although both cell lines exhibited specific binding, only the Caco-2 cell line responded to heat-stable enterotoxin with increased guanylyl cyclase activity. Cloning and expression studies confirmed that the receptor present in Caco-2 cells is a homologue of guanylyl cyclase C, a known transmembrane heat-stable enterotoxin receptor. Expression of the receptor in differentiating Caco-2 cells increases with cell maturation, indicating that these cells are a suitable model for future studies. However, Northern and polymerase chain reaction analyses demonstrated that guanylyl cyclase C is not expressed in IEC-6 cells, strongly suggesting the presence of a novel heat-stable enterotoxin receptor that is not coupled to guanylyl cyclase activity.

  View details for DOI 10.1152/ajpgi.1993.264.1.G172

  View details for Web of Science ID A1993KK29100070

  View details for PubMedID 8381596

• The heat-stable enterotoxin receptor: a probe for ligand hunting. Journal of pediatric gastroenterology and nutrition Cohen, M. B. 1992; 15 (3): 337-8

  View details for DOI 10.1097/00005176-199210000-00022

  View details for PubMedID 1331391

• A GRADIENT IN EXPRESSION OF THE ESCHERICHIA-COLI HEAT-STABLE ENTEROTOXIN RECEPTOR EXISTS ALONG THE VILLUS-TO-CRYPT AXIS OF RAT SMALL-INTESTINE BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS COHEN, M. B., MANN, E. A., LAU, C., HENNING, S. J., GIANNELLA, R. A. 1992; 186 (1): 483-490

  Abstract

  Binding of Escherichia coli heat-stable enterotoxin to its receptor is critical to the initiation of toxin-induced secretion and diarrheal disease; it is also likely, however, that this receptor binds an endogenous ligand. In order to characterize the expression of the heat-stable enterotoxin receptor in the small intestine, we isolated epithelial cells from villus tip to crypt in rat jejunum and ileum. Binding of radiolabeled toxin was maximal in the villus preparations and gradually decreased along the villus-to-crypt axis, paralleling the decline of sucrase activity. Northern blots of total RNA identified a single heat stable enterotoxin receptor transcript (3.8 kb), predominantly in the villus cell fractions. In situ hybridization demonstrated clear signal in the villus cells with no apparent signal in the crypt cells, lamina propria or muscularis. Expression of this receptor was greatest after enterocytes leave the proliferative cycle and enter villi. This pattern of gene and protein expression may reflect a role of this receptor in binding endogenous ligands which in turn may regulate intestinal ion flux along the villus-to-crypt axis.

  View details for DOI 10.1016/S0006-291X(05)80833-2

  View details for Web of Science ID A1992JE59900067

  View details for PubMedID 1378729

• JEJUNAL TOXIN INACTIVATION REGULATES SUSCEPTIBILITY OF THE IMMATURE RAT TO ST(A) GASTROENTEROLOGY COHEN, M. B., GIANNELLA, R. A. 1992; 102 (6): 1988-1996

  Abstract

  The immature rat jejunum demonstrates an increased response, sensitivity, and susceptibility to heat-stable enterotoxin. In the present study, the hypothesis that this increased secretory response results from diminished jejunal toxin inactivation and persistence of biologically active toxin was tested. A modification of toxin injected into ligated jejunal loops was observed in both adult and immature rats. However, in the immature jejunum there was also persistence of biologically active toxin and continued toxin-induced secretion. In contrast, in the adult jejunum there was inactivation of toxin and cessation of secretion. Incubation of toxin with luminal fluid, pancreatic fluid, or jejunal brush border membranes resulted in toxin alteration. However, a completely inactive toxin species was generated only after incubation with jejunal organ culture slices. It is concluded that (a) incomplete toxin inactivation in the immature rat jejunum contributes to prolonged intestinal secretion and that (b) the inactivation process is multifactorial, but it is likely that final toxin inactivation requires the participation of the enterocyte. These findings may help explain the increased responsiveness of the immature intestine to heat-stable enterotoxin.

  View details for DOI 10.1016/0016-5085(92)90324-R

  View details for Web of Science ID A1992HW35600022

  View details for PubMedID 1587417

• THE JEJUNAL SECRETORY RESPONSE TO ESCHERICHIA-COLI HEAT-STABLE ENTEROTOXIN IS PROLONGED IN MALNOURISHED RATS PEDIATRIC RESEARCH COHEN, M. B., NOGUEIRA, J., LANEY, D. W., CONTI, T. R. 1992; 31 (3): 228-233

  Abstract

  Undernutrition in human infants is associated with more prolonged episodes of diarrheal disease. Therefore, we tested the hypothesis that malnutrition prolongs the duration of Escherichia coli heat-stable enterotoxin-induced rat jejunal secretion. At weaning, rats were separated into two groups: malnourished rats were fed 50% of the previous day's intake of the fully fed control group. After approximately 2 wk of pair feeding, when malnourished rats weighed less than or equal to 60% of the full fed control group, we measured the secretory response to heat-stable enterotoxin in ligated jejunal loops. Toxin-induced secretion was equal in both groups until 30 min incubation time, after which net secretion continued to increase in the malnourished group but decreased in the fully fed group. Jejunal brush border membranes prepared from malnourished and fully fed rats demonstrated similar heat-stable enterotoxin receptor density, avidity of binding and guanyl cyclase activation. In both groups, radiolabeled toxin injected into in situ jejunal loops was converted into an altered radioligand unable to bind to brush border membranes. However, in malnourished rats, there was both increased appearance of two additional radioligands that still retained their ability to bind to brush border membranes and persistence of biologically active unlabeled toxin as measured in the suckling mouse bioassay. Our studies demonstrate that reduced or delayed inactivation of heat-stable enterotoxin, with continued presence of active toxin species, may contribute to prolonged secretion in the jejunum of malnourished rats.

  View details for DOI 10.1203/00006450-199203000-00007

  View details for Web of Science ID A1992HF34600006

  View details for PubMedID 1348576

• ESCHERICHIA-COLI ENTEROTOXIN (STA) BINDS TO RECEPTORS, STIMULATES GUANYL CYCLASE, AND IMPAIRS ABSORPTION IN RAT COLON GASTROENTEROLOGY MEZOFF, A. G., GIANNELLA, R. A., EADE, M. N., COHEN, M. B. 1992; 102 (3): 816-822

  Abstract

  To determine the contribution of the colon in Escherichia coli heat-stable enterotoxin-mediated diarrheal disease, toxin binding, guanyl cyclase activation, and toxin-induced water flux in the rat colon and ileum were compared. Scatchard analysis suggested a single class of heat-stable enterotoxin receptors with an affinity constant of binding of 10(9) L/mol in both colonocytes and ileocytes; however, the number of toxin receptors per cell was 3.5-fold greater in coloncytes than ileocytes (8.32 +/- 1.33 x 10(5) vs. 2.33 +/- 0.28 x 10(5) receptors per cell; P = 0.02). Heat-stable enterotoxin stimulated guanyl cyclase activation in an identical dose-dependent manner in proximal colonic and ileal membranes, with similar sensitivity and maximum response. Heat-stable enterotoxin also inhibited net water flux to a similar degree in both colon and ileum (-47.8 vs. -48.4 microL.cm-1.h-1, respectively) at a dose of 8 nmol/L. At this dose in the colon, because of a higher baseline of absorption, absorption continued, but at a diminished level. At this dose in the ileum, heat-stable enterotoxin induced net secretion. These data are consistent with the concept that heat-stable enterotoxin-induced diarrheal disease results from a decreased absorptive capacity in the colon in the face of increased small intestinal fluid secretion.

  View details for DOI 10.1016/0016-5085(92)90163-S

  View details for Web of Science ID A1992HF72100009

  View details for PubMedID 1347028

• COMPLICATIONS OF PERCUTANEOUS LIVER-BIOPSY IN CHILDREN GASTROENTEROLOGY COHEN, M. B., AKADER, H. H., LAMBERS, D., HEUBI, J. E. 1992; 102 (2): 629-632

  Abstract

  To determine the frequency and nature of complications after liver biopsy and whether risk factors could be identified to predict these complications, the medical records of all patients (age, 1 week to 28 years) who underwent a percutaneous liver biopsy at Children's Hospital over a 6-year period (1981-1986) were reviewed. Data were collected from 469 (97%) of 483 eligible charts. Twenty-one patients (4.5%) experienced major complications including bile leak (n = 3, 0.6%), prolonged drainage of ascitic fluid (n = 1, 0.2%), pneumothorax (n = 1, 0.2%), bleeding requiring transfusion (n = 13, 2.8%), and death (n = 3, 0.6%). A subgroup of patients (n = 37) with cancer or bone marrow transplantation was found to be at a nearly fivefold greater risk for transfusion than patients with other diagnoses (P = 0.02). All three deaths in previously stable patients occurred in this same high-risk group of patients with cancer or bone marrow transplantation (P less than 0.001). Two deaths resulted from disseminated intravascular coagulation and one from bleeding. Diagnosis, age, number of percutaneous passes, and prebiopsy coagulation studies were not predictive of subsequent complications. It is concluded that bleeding that requires transfusion is the most common liver biopsy complication and that it occurs more frequently in children than previously reported. Children with cancer or those who have undergone bone marrow transplantation are at a greater risk for bleeding and death following percutaneous liver biopsy.

  View details for DOI 10.1016/0016-5085(92)90112-C

  View details for Web of Science ID A1992HA63900032

  View details for PubMedID 1732131

• HEMORRHAGIC COLITIS ASSOCIATED WITH ESCHERICHIA-COLI O157-H7 ADVANCES IN INTERNAL MEDICINE, VOL 37 COHEN, M. B., GIANNELLA, R. A., Stollerman, G. H. 1992; 37: 173-195

  Abstract

  E. coli O157:H7, the predominant serotype of EHEC, is a cause of both outbreaks and sporadic cases of hemorrhagic colitis. In sporadic cases, and especially in outbreaks, there is an association with the consumption of improperly cooked ground beef. Both young children and geriatric patients have an increased attack rate for EHEC infection as well as an increased incidence of the two sequelae of intestinal infection with EHEC, hemolyticuremic syndrome, and thrombotic thrombocytopenic purpura. The hallmark of hemorrhagic colitis due to EHEC is the development of bloody diarrhea several days after the onset of nonbloody diarrhea and abdominal pain. Fever is usually absent or low-grade. The pathogenesis of EHEC infection is probably related to at least two bacterial virulence factors: adherence of bacteria to intestinal mucosa and production of one or more cytotoxins. These cytotoxins are closely related to Shiga toxin and therefore are often referred to as Shiga-like toxins. Treatment for hemorrhagic colitis is supportive care; most illnesses are self-limited. At present, there is no evidence that antimicrobial therapy shortens the course of illness or prevents the development of sequelae.

  View details for Web of Science ID A1992BZ78K00009

  View details for PubMedID 1557995

• MECHANISMS OF INCREASED SUSCEPTIBILITY OF IMMATURE AND WEANED PIGS TO ESCHERICHIA-COLI HEAT-STABLE ENTEROTOXIN PEDIATRIC RESEARCH MEZOFF, A. G., JENSEN, N. J., COHEN, M. B. 1991; 29 (5): 424-428

  Abstract

  Pigs demonstrate an increased sensitivity and susceptibility to Escherichia coli heat-stable enterotoxin (STa) in the 1st wk of life and immediately after weaning. To determine the possible mechanisms for this increased susceptibility, we compared STa binding, guanylate cyclase activation, and photoaffinity cross-linking to porcine jejunal brush border membranes prepared from immature (less than or equal to 1 wk of age) versus adult pigs as well as 3-wk-old weaned versus unweaned pigs. The STa binding capacity of immature pigs was nearly twice that of adult pigs (11.73 +/- 1.52 versus 6.00 +/- 0.96 x 10(-11) mol/L, p less than 0.001), and the STa binding capacity of weaned pigs was nearly three times greater than that of unweaned pigs (17.48 +/- 2.10 versus 4.86 +/- 1.02 x 10(-11) mol/L, p less than 0.001). Scatchard analysis suggested a single class of STa receptor, with an association of binding constant of approximately 10(9) L/mol at all ages. Maximum guanylate cyclase response (expressed as pmol cyclic GMP generated/mg brush border membrane protein/min) was greater in immature versus adult pigs (1312 +/- 831 versus 320 +/- 92, p less than 0.02). Weaned pigs had a greater maximum guanylate cyclase activation than unweaned pigs (1126 +/- 692 versus 624 +/- 298); however, this difference was not statistically significant. Autoradiograms demonstrated specific cross-linking of 125I-STa to a number of distinct radiolabeled bands (62, 66, 84, 92, 160, and 165 kD). There was a difference in the size and trypsin sensitivity of these radiolabeled bands as a function of age and weaning. Treatment with trypsin decreased the intensity of the 160 to 165-kD bands while increasing the intensity of the 62- to 66- and 84- to 92-kD bands. These differences in STa binding, guanylate cyclase activation, and STa receptor size may increase the susceptibility of pigs during the 1st wk of life and at weaning to STa-mediated diarrheal disease.

  View details for DOI 10.1203/00006450-199105010-00003

  View details for Web of Science ID A1991FJ39500003

  View details for PubMedID 1680229

• ETIOLOGY AND MECHANISMS OF ACUTE INFECTIOUS DIARRHEA IN INFANTS IN THE UNITED-STATES JOURNAL OF PEDIATRICS COHEN, M. B. 1991; 118 (4): S34-S39

  Abstract

  Infectious diarrhea, caused by a wide variety of viral, bacterial and parasitic pathogens, is a common reason for morbidity and hospitalization for children in the United States. Overall, rotavirus is the most common cause of acute diarrheal disease in infants. Salmonella, Shigella, and Campylobacter are the most frequently isolated bacterial pathogens, and Giardia and Cryptosporidium are the parasites that most commonly produce acute infectious diarrhea. The mechanisms by which these enteropathogens cause diarrhea are highly variable, and include crypt cell proliferation, cellular invasion, elaboration of enterotoxins or cytotoxins, and enteroadhesion. In infants the incidence of diarrheal disease is higher and the severity of the illness is greater than in older children and adults. An increased rate of exposure to enteropathogens, as a result of fecal-oral contamination, may explain some of the increased incidence of diarrhea in infants. However, age-specific differences in host defense mechanisms may also account for the increased susceptibility to and severity of certain enteric infections in infants.

  View details for DOI 10.1016/S0022-3476(05)81423-4

  View details for Web of Science ID A1991FG28300003

  View details for PubMedID 2007955

• CROHN DISEASE IN AN INFANT WITH CENTRAL-NERVOUS-SYSTEM THROMBOSIS AND PROTEIN-LOSING ENTEROPATHY JOURNAL OF PEDIATRICS MEZOFF, A. G., COHEN, M. B., MAISEL, S. K., FARRELL, M. K. 1990; 117 (3): 436-439

  View details for DOI 10.1016/S0022-3476(05)81090-X

  View details for Web of Science ID A1990DX95300019

  View details for PubMedID 2202803

• AGE-RELATED DIFFERENCES IN RECEPTORS FOR ESCHERICHIA-COLI HEAT-STABLE ENTERO-TOXIN IN THE SMALL AND LARGE-INTESTINE OF CHILDREN GASTROENTEROLOGY COHEN, M. B., GUARINO, A., SHUKLA, R., GIANNELLA, R. A. 1988; 94 (2): 367-373

  Abstract

  Escherichia coli that produce heat-stable enterotoxin are a worldwide cause of diarrheal disease, especially in children. We examined small and large intestinal specimens from children of various ages for the presence of E. coli heat-stable entero-toxin receptors and determined whether the number of receptors or the binding affinity of these receptors was related to the age of the child. We observed specific binding of 125I-heat-stable enterotoxin to all small intestinal and colonic specimens. However, a greater number of receptors per microgram of membrane protein were present in infants and the number of receptors rapidly decreased with increasing age. We also observed that increased heat-stable enterotoxin stimulation of guanylate cyclase was correlated with increased receptor density. We suggest that a greater number of gastrointestinal receptors for heat-stable enterotoxin, capable of activating more guanylate cyclase, may contribute to the increased severity of diarrhea noted in young children exposed to enterotoxigenic E. coli.

  View details for DOI 10.1016/0016-5085(88)90423-4

  View details for Web of Science ID A1988L806800013

  View details for PubMedID 2891585

• T84-CELL RECEPTOR-BINDING AND GUANYL CYCLASE ACTIVATION BY ESCHERICHIA-COLI HEAT-STABLE TOXIN AMERICAN JOURNAL OF PHYSIOLOGY GUARINO, A., COHEN, M., THOMPSON, M., DHARMSATHAPHORN, K., GIANNELLA, R. 1987; 253 (6): G775-G780

  Abstract

  Escherichia coli heat-stable enterotoxin (STa) induces intestinal secretion by binding to enterocyte receptors and activating the guanylate cyclase-guanosine 3',5'-cyclic monophosphate (cGMP) system. The intermediate steps between binding of STa and secretion are poorly understood, due in part to the lack of a convenient system to study the effects of STa at the cellular level. To establish such a model, we investigated the binding of 125I-STa, STa activation of guanylate cyclase, and STa-induced increase in cGMP production in a well-characterized human colonic cell line, T84. Binding was specific, linear with cell number, and time, temperature and pH dependent, and reversible. ST may also be internalized by these cells. Addition of unlabeled STa competitively inhibited binding of 125I-STa. These parameters closely resemble those described in intact rat enterocytes and cell-free membrane preparations. STa stimulated guanylate cyclase and cGMP production in a dose-related manner. The similar dose-response relationships for binding, guanylate cyclase stimulation by STa, and cGMP production suggest that the guanylate cyclase-cGMP system is coupled to ST occupancy of specific receptors. These data, together with the fact that STa induces chloride secretion from T84 cells suggest that T84 cells are a suitable and convenient system to study the cellular mechanism of action of STa.

  View details for DOI 10.1152/ajpgi.1987.253.6.G775

  View details for Web of Science ID A1987L420100044

  View details for PubMedID 2892417

• BINDING OF ESCHERICHIA-COLI HEAT-STABLE ENTEROTOXIN TO RAT INTESTINAL BRUSH-BORDERS AND TO BASOLATERAL MEMBRANES DIGESTIVE DISEASES AND SCIENCES GUARINO, A., COHEN, M. B., OVERMANN, G., THOMPSON, M. R., GIANNELLA, R. A. 1987; 32 (9): 1017-1026

  Abstract

  We studied the binding of E. coli heat-stable enterotoxin (STa) to rat brush borders (BB) and to basolateral membranes (BLM) using a biologically active monoiodinated radioligand [( 125I]STa) and highly enriched BB and BLM preparations free of other significant organelle contamination. Binding of [125I]STa to BB was specific; time-, temperature-, and pH-dependent; saturable; and partially reversible. Nonlabeled toxin competitively inhibited the binding of radioligand to BB in a dose-related manner. Scatchard analysis revealed a single class of receptors with an apparent affinity constant of 8.7 +/- 1.5 X 10(8) l/mol. Binding was not affected by amino acids, sugars, and lectins. Proteolytic enzymes significantly decreased binding, although several did so by modifying the radioligand. Trypsin inhibited binding without modifying the radioligand thus supporting the proteinaceous nature of the receptor. Since the enrichment in binding activity in the BB over the homogenate was significantly lower than the enrichment in sucrase activity, we concluded that binding activity is probably associated with other membranous domains, but direct examination revealed no binding activity on basolateral membranes.

  View details for DOI 10.1007/BF01297193

  View details for Web of Science ID A1987K175500011

  View details for PubMedID 3304888

• SMALL AND LARGE INTESTINAL GUANYLATE-CYCLASE ACTIVITY IN CHILDREN - EFFECT OF AGE AND STIMULATION BY ESCHERICHIA-COLI HEAT-STABLE ENTEROTOXIN PEDIATRIC RESEARCH GUARINO, A., COHEN, M. B., GIANNELLA, R. A. 1987; 21 (6): 551-555

  Abstract

  Heat-stable enterotoxin (ST) producing Escherichia coli are a common cause of diarrhea in infants. ST acts through the stimulation of the guanylate cyclase-cGMP system. The effect of ST on the human intestine has not been investigated nor is any information available on the activity, distribution, or development of guanylate cyclase activity in the human intestine. The purpose of this study, therefore, was to characterize, these aspects of guanylate cyclase activity and to study the effect of ST on the activity and responsiveness of guanylate cyclase in the intestine of infants and children of various ages. We measured guanylate cyclase activity in 35 intestinal specimens, obtained operatively, from children aged 1 day to 16 yr. Guanylate cyclase activity was linear with protein concentration and time. Basal activity was similar in small intestine and in colon. In the small intestine, however, basal guanylate cyclase activity varied with age. It was maximal in children 1 day of age, and although somewhat variable, decreased with age thereafter. In colon, an age-related pattern was not found. E. coli ST stimulated guanylate cyclase activity in all specimens in a dose-related manner. In the small intestine ST-stimulation of guanylate cyclase was twice that found in colon. Furthermore, age affected the response of small intestinal guanylate cyclase to ST. Maximal response to ST was observed in children 1 day of age and ST stimulation was significantly greater in children less than 1 yr of age than in older children. In the colon, the response of guanylate cyclase to ST did not change with age.(ABSTRACT TRUNCATED AT 250 WORDS)

  View details for DOI 10.1203/00006450-198706000-00009

  View details for Web of Science ID A1987H502600008

  View details for PubMedID 2885801

• ASSOCIATION AND DISSOCIATION OF ESCHERICHIA-COLI HEAT-STABLE ENTEROTOXIN FROM RAT BRUSH-BORDER MEMBRANE-RECEPTORS INFECTION AND IMMUNITY COHEN, M. B., THOMPSON, M. R., OVERMANN, G. J., GIANNELLA, R. A. 1987; 55 (2): 329-334

  Abstract

  Escherichia coli heat-stable enterotoxin (ST) binds to receptors on rat intestinal cells and brush border membranes (BBM). We devised experiments to examine the reversibility of ST binding. We found that both 125I-labeled ST and native ST were spontaneously dissociable from the BBM receptor. Radiolabeled ST bound to BBM was also dissociated by the addition of avid goat anti-ST antiserum. Furthermore, using a computer program for analysis of ligand binding, we calculated an apparent Ka of 10(8) liters/mol from competitive inhibition and saturation-binding data. This is significantly lower than the value previously reported by others. Our findings, of a lower Ka and a reversible ST-binding process, suggest that a therapeutic strategy of removing bound ST from its receptor or competing with the enterocyte receptor for unbound ST might be successful in terminating ST-induced secretion.

  View details for DOI 10.1128/IAI.55.2.329-334.1987

  View details for Web of Science ID A1987F687200009

  View details for PubMedID 3542830

  View details for PubMedCentralID PMC260330

• THE IMMATURE RAT SMALL-INTESTINE EXHIBITS AN INCREASED SENSITIVITY AND RESPONSE TO ESCHERICHIA-COLI HEAT-STABLE ENTEROTOXIN PEDIATRIC RESEARCH COHEN, M. B., MOYER, M. S., LUTTRELL, M., GIANNELLA, R. A. 1986; 20 (6): 555-560

  Abstract

  Escherichia coli which elaborate heat stable enterotoxin (ST) are a major cause of endemic diarrhea in infants. The reason(s) for this increased susceptibility of infants to ST-mediated diarrhea is unknown. We investigated the possibility that the immature (14 and 21 day old) rat small intestine is more sensitive to ST than is the adult. Initially we found there was a 600-fold increased jejunal sensitivity to ST in the immature animals as measured by dose required for half maximal secretion. Also there was a greater jejunal secretory response in the immature animals (14 greater than or equal to 21 days old greater than adult). To determine the cause for this increased sensitivity and secretory response to ST, we examined: 1) binding characteristics of 125I-ST to brush border membrane (BBM) receptors and 2) membrane bound guanylate cyclase activation by ST in both immature and adult rats. Our findings demonstrate that more ST receptors are present in jejunal BBM from 14- and 21-day-old rats than in jejunal BBM from adult rats (2.34 +/- 0.18, 2.85 +/- 0.82, and 0.79 +/- 0.13 X 10(12) receptors/mg BBM protein, respectively), while the affinity of the BBM receptor for ST is similar at all three ages in both jejunum and ileum. Furthermore, both the jejunum and ileum of the rats of all three ages revealed an equal sensitivity of guanylate cyclase to activation by ST. These findings suggest that the increased number of jejunal receptors in the immature rat may, in part, explain the increased sensitivity and secretory response observed in vivo.

  View details for DOI 10.1203/00006450-198606000-00017

  View details for Web of Science ID A1986C430200014

  View details for PubMedID 2872650