- General Surgery
Assistant Professor - Med Center Line, Surgery - Abdominal Transplantation
Residency: Yale University Office of the Registrar (2006) CT
Internship: Yale University Office of the Registrar (2003) CT
Medical Education: Case Western Reserve School of Medicine (2002) OH
Fellowship: Stanford University (2011) CA
Residency: Stanford University - General Surgery (2009) CA
Board Certification: American Board of Surgery, General Surgery (2009)
Superior Hypertension Management in Pediatric Kidney Transplant Patients After Native Nephrectomy.
2018; 102 (7): 1172–78
BACKGROUND: Native nephrectomy in pediatric kidney transplant recipients is performed for multiple indications. Posttransplant hypertension requiring medical management is common, and the effect of native nephrectomy on posttransplant hypertension is poorly studied. Our aim is to evaluate the impact of native nephrectomy on posttransplant hypertension.METHODS: One hundred thirty-six consecutive pediatric kidney transplant recipients from 2007 to 2012 were studied at a single institution and divided into 2 groups: no nephrectomy and native nephrectomy (unilateral and bilateral nephrectomy). Antihypertensive medication use was evaluated before nephrectomy/transplant, at discharge from transplant and at 1, 3, and 5 years posttransplant.RESULTS: In a bivariate analysis, nephrectomy was associated with a significant reduction in the percentage of patients requiring antihypertensive medication at the time of discharge (27.3%) and 1 year posttransplant (10.7%) as compared with patients without nephrectomy (71.7%, and 50%, respectively, P < 0.05). This trend toward reduction in antihypertensive medication in the nephrectomy group as compared with the no nephrectomy group persisted at 3 (18.6% versus 43.2%) and 5 years (19.7% versus 37.5%) posttransplant. Multivariable logistic regression demonstrated that patients without native nephrectomy had higher odds of requiring antihypertensive medication at the time of discharge (3.3) and 1 year (5.2) as compared with patients who underwent native nephrectomy (P = 0.036 and P = 0.013, respectively).CONCLUSIONS: Native nephrectomy reduces the odds of needing antihypertensive medication after transplant. The impact of native nephrectomy is crucial to the comprehensive management of pediatric transplant recipients where medication compliance is challenging and lifelong hypertension is known to negatively impact cardiovascular health.
View details for PubMedID 29953422
Combined En-Bloc Heart Liver Transplantation in Children with Congenital Heart Disease Complicated by Cardiac Cirrhosis
LIPPINCOTT WILLIAMS & WILKINS. 2018: S295
View details for Web of Science ID 000444541200473
It is time to revise the kidney allocation system to restore the pediatric advantage.
American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons
View details for PubMedID 29706006
Impact of the kidney allocation system on young pediatric recipients
2018; 32 (4): e13223
The kidney allocation system (KAS) altered pediatric candidate prioritization. We determined KAS's impact on pediatric kidney recipients by examining delayed graft function (DGF) rates from 2010 to 2016. A propensity score-matched pediatric recipients pre- and post-KAS. A semiparametric decomposition analysis estimated the contributions of KAS-related changes in donor characteristics and dialysis time on DGF rate. The unadjusted odds of DGF were 69% higher post-KAS for young (<10 years at listing) recipients (N = 1153, P = .02) but were not significantly increased for older pediatric (10-17 years at listing) recipients (N = 2624, P = .48). Post-KAS, young recipients received significantly fewer pediatric (<18 years) donor kidneys (21% vs 32%, P < .01) and had longer median pretransplant dialysis time (603 vs 435 days, P < .01). After propensity score matching, post-KAS status increased the odds of DGF in young recipients 71% (OR 1.71, 95% CI 1.01-2.46). In decomposition analysis, 24% of the higher DGF rate post-KAS was attributable to donor characteristics and 19% to increased recipient dialysis time. In a confirmatory survival analysis, DGF was associated with a 2.2 times higher risk of graft failure (aHR2.28, 95% CI 1.46-3.54). In conclusion, KAS may lead to worse graft survival outcomes in children. Allocation changes should be considered.
View details for PubMedID 29457274
Negative Impact of Kidney Allocation System (KAS) on Pediatric Recipients
WILEY. 2018: 15
View details for Web of Science ID 000419034500006
Effect of Liver Transplant on Long-term Disease-Free Survival in Children With Hepatoblastoma and Hepatocellular Cancer
2015; 150 (12): 1150-1158
Hepatoblastoma (HBL) and hepatocellular cancer (HCC) are the most common primary hepatic malignant neoplasms in childhood. Given the rarity of these childhood tumors and their propensity to present at advanced stages, updated long-term data are needed.To determine the efficacy of liver transplant in children with HBL or HCC.This single-institution retrospective medical record review and analysis spanned from January 1, 1997, through September 17, 2014, at Stanford University School of Medicine. A total of 40 patients younger than 18 years underwent liver transplant for treatment of HBL (n = 30) or HCC (n = 10) during the study period, with follow-up until September 17, 2014. Patients who underwent transplant for HCC included those with tumors that were greater in size than what is proposed by the Milan (a single tumor measuring ≤5 cm or ≤3 nodules measuring ≤3 cm) and University of California, San Francisco (single tumor measuring ≤6.5 cm or ≤3 nodules measuring ≤4.5 cm and a total diameter of ≤8 cm), criteria.Disease-free and overall patient survival and graft survival.Using a Kaplan-Meier survival analysis, 1-, 5-, and 10-year disease-free survival after liver transplant was 93%, 82%, and 82%, respectively, for 30 patients with HBL and 90%, 78%, and 78%, respectively, for 10 patients with HCC. Risk factors associated with HBL recurrence after transplant included having pretreatment extent of disease stage IV lesions and a longer waiting list time and being older at the time of the transplant. Recurrence was found in 2 of 7 patients with HBL and pretransplant metastases, which were not found to be an independent risk factor for recurrence. Patients with HCC larger than the proposed Milan and University of California, San Francisco, criteria experienced good 5-year disease-free (82%) and overall (78%) survival after transplant. Being older at the time of transplant (18 vs 11 years; P = .04) and the presence of metastatic disease (1 patient vs none; P = .05) were associated with HCC tumor recurrence.Liver transplant combined with chemotherapy is an excellent treatment that provides long-term disease-free survival in children diagnosed with advanced HBL and HCC. Early addition to a waiting list and aggressive multimodal therapy provide excellent results. Transplant should still be considered in children with HCC larger than the Milan and University of California, San Francisco, criteria.
View details for DOI 10.1001/jamasurg.2015.1847
View details for Web of Science ID 000367990700010
Pediatric deceased donor renal transplantation: An approach to decision making II. Acceptability of a deceased donor kidney for a child, a snap decision at 3 AM
2015; 19 (7): 785-791
Allocation of deceased donor kidneys is based on several criteria; however, the final decision to accept or reject the offered kidney is made by the potential recipient's transplant team (surgeon/nephrologist). Several considerations including assessment of the donor quality, the HLA match between the donor and the recipient, several recipient factors, the geographical location of the recipient, and the organ all affect the decision of whether or not to finally accept the organ for a particular recipient. This decision needs to be made quickly, often on the spot. Maximizing the benefit from this scarce resource raises difficult ethical issues. The philosophies of equity and utility are often competing. This article will discuss the several considerations for the pediatric nephrologist while accepting a deceased donor kidney for a particular pediatric patient.
View details for DOI 10.1111/petr.12582
View details for Web of Science ID 000362580100025
View details for PubMedID 26426405
Pediatric deceased donor renal transplantation: An approach to decision making I. Pediatric kidney allocation in the USA: The old and the new
2015; 19 (7): 776-784
Renal transplantation is the treatment of choice for children with end-stage renal disease. More than 50% of children receive a deceased donor renal transplant. Marked disparity between the number of children on the renal transplant wait list and the supply has prompted numerous advances to increase supply as well as maximize the utility of donor organs. Allocation of deceased donor kidneys is based on several criteria. The organ allocation system policy is continually evaluated and changed incrementally to optimize allocation. We, in the United Sates, are in the process of transitioning into a new kidney allocation system to enhance post-transplant survival benefit, increase utilization of donated kidneys, and increase transplant access for biologically disadvantaged candidates. This review will provide a brief overview of the organ sharing system in the United States, compare the "old" and the "new" allocation system, and discuss the considerations for the pediatric nephrologist while accepting a deceased donor kidney for a particular pediatric patient.
View details for DOI 10.1111/petr.12569
View details for Web of Science ID 000362580100024
View details for PubMedID 26426316
Recurrent Hepatocellular Carcinoma and Poorer Overall Survival in Patients Undergoing Left-sided Compared With Right-sided Partial Hepatectomy.
Journal of clinical gastroenterology
2015; 49 (2): 158-164
We aimed to determine the incidence and predictors of recurrent hepatocellular carcinoma (HCC) after partial hepatectomy.Liver transplantation is the preferred treatment for selected patients with HCC, but access to donor organs is limited. Partial hepatectomy is another accepted treatment option; however, postoperative recurrence is frequently observed.This is a retrospective cohort study of 107 consecutive patients who underwent partial hepatectomy for HCC between January 1993 and February 2011 at a US University Medical Center. Study endpoints were recurrent HCC, death, loss to follow-up, or last visit without HCC.The study cohort was 78% male with a median age of 61 years and 59% Asians. A total of 50 patients developed recurrent HCC (46.7%) after a median follow-up of 12 (1 to 69) months postresection. Recurrent HCC was significantly higher in patients with left-sided resection (41% at year 1, 54% at year 2, 62% at year 3, 81% at year 4, and 90% at year 5) compared with right-sided resection (18% at year 1, 34% at year 2, 36% at year 3, 44% at year 4, and 72% at year 5). In multivariate Cox proportional hazards model also inclusive of anatomic resection and TNM stage 3/4, left-sided resection was significantly associated with increased HCC recurrence (hazard ratio, 2.13; P=0.02; 95% confidence interval, 1.08-4.2) compared with right-sided resection.HCC recurrence rate is higher among those undergoing left-sided resection: 54% at year 2 and 81% at year 4. Liver transplantation should be considered in patients who are at high risk for recurrence.
View details for DOI 10.1097/MCG.0000000000000144
View details for PubMedID 24804988
- Late hepatic artery thrombosis in pediatric liver transplantation: an incomplete story. Liver transplantation 2014; 20 (5): 512-513
Primary surgical resection versus liver transplantation for transplant-eligible hepatocellular carcinoma patients.
Digestive diseases and sciences
2014; 59 (1): 183-191
Hepatocellular carcinoma (HCC) is a leading cause of mortality worldwide. Existing studies comparing outcomes after liver transplantation (LT) versus surgical resection among transplant-eligible patients are conflicting.The purpose of this study was to compare long-term survival between consecutive transplant-eligible HCC patients treated with resection versus LT.The present retrospective matched case cohort study compares long-term survival outcomes between consecutive transplant-eligible HCC patients treated with resection versus LT using intention-to-treat (ITT) and as-treated models. Resection patients were matched to LT patients by age, sex, and etiology of HCC in a 1:2 ratio.The study included 171 patients (57 resection and 114 LT). Resection patients had greater post-treatment tumor recurrence (43.9 vs. 12.9 %, p < 0.001) compared to LT patients. In the as-treated model of the pre-model for end stage liver disease (MELD) era, LT patients had significantly better 5-year survival compared to resection patients (100 vs. 69.5 %, p = 0.04), but no difference was seen in the ITT model. In the multivariate Cox proportional hazards model, inclusive of age, sex, ethnicity, tumor stage, and MELD era (pre-MELD vs. post-MELD), treatment with resection was an independent predictor of poorer survival (HR 2.72; 95 % CI, 1.08-6.86).Transplant-eligible HCC patients who received LT had significantly better survival than those treated with resection, suggesting that patients who can successfully remain on LT listing and actually undergo LT have better outcomes.
View details for DOI 10.1007/s10620-013-2947-8
View details for PubMedID 24282054
Current options for management of biliary atresia
2013; 17 (2): 95-98
It is encouraging that we are improving the technical aspects of treatment modalities for biliary atresia. However, it is clear that more needs to be done to best develop new treatment plans while applying the modalities we have (porto-enterostomy or liver transplantation or both) in a way that will afford the best survival and quality-of-life. This review article will discuss a number of points that are vital to improving care and illustrates the need to further scrutinize treatment decisions.
View details for DOI 10.1111/petr.12040
View details for Web of Science ID 000315467000009
View details for PubMedID 23347466
Changes in natural killer cell subsets in pediatric liver transplant recipients
2012; 16 (2): 176-182
NK cells are important in the immune response against tumors and virally infected cells. A balance between inhibitory and activating receptors controls the effector functions of NK cells. We examined the fate of circulating NK cells and the expression of the NK cell-activating receptors in pediatric liver transplant recipients. Blood specimens were collected from 38 pediatric liver transplant recipients before transplant, and at one wk, one, three, six, and nine months, and one yr post-transplant. PBMCs were isolated and analyzed for the levels of NK cell activation receptors NKp30, NKp46, and NKG2D in the CD56(dim) CD16(+) and CD56(bright) CD16(+/-) subsets of NK cells. We demonstrated that there is a significant decrease in the percentage of circulating NK cells post-transplant (pretransplant 7.69 ± 1.54 vs. one wk post-transplant 1.73 ± 0.44) in pediatric liver transplant recipients. Interestingly, NKp30 expression is significantly increased, while NKp46 and NKG2D levels remain stable on the NK cells that persist at one wk post-transplant. These data indicate that the numbers and subsets of circulating NK cells are altered in children after liver transplantation.
View details for DOI 10.1111/j.1399-3046.2012.01653.x
View details for Web of Science ID 000300709600017
View details for PubMedID 22360401
View details for PubMedCentralID PMC3306774
Circulating interferon-gamma-inducible Cys-X-Cys chemokine receptor 3 ligands are elevated in humans with aortic aneurysms and Cys-X-Cys chemokine receptor 3 is necessary for aneurysm formation in mice
JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY
2012; 143 (3): 704-710
Inflammation is associated with the formation of aortic aneurysm. This study investigates the role of inducible Cys-X-Cys chemokine receptor 3 and its ligands in the pathogenesis of arterial aneurysms.Plasma samples from patients with or without a diagnosis of thoracic aortic aneurysms were analyzed by enzyme-linked immunosorbent assay for the T-helper 1 cytokine interferon-γ and the interferon-γ-inducible chemokine receptor 3 ligands: interferon-inducible protein-10, interferon-inducible T-cell alpha chemoattractant, and monokine induced by interferon gamma. Patient charts were reviewed for demographics, initial aortic diameter, and growth rates. Aneurysm diameter and growth rates were correlated with plasma cytokine and chemokine levels using linear regression analysis. We used an animal model of aneurysm formation, where calcium chloride is applied topically to the carotid arteries of wild-type and Cys-X-Cys chemokine receptor 3(-/-) mice. After 10 weeks, the arteries were harvested and analyzed by histology and immunohistochemistry.Patients with thoracic aortic aneurysms had significant elevations in circulating interferon-γ, interferon-inducible protein-10, interferon-inducible T-cell alpha chemoattractant, and monokine induced by interferon gamma compared with referent patients (P < .001). Cytokine and chemokine plasma levels did not correlate with aneurysm size or growth rates. Cys-X-Cys chemokine receptor 3(-/-) mice were protected from aneurysm formation and showed decreased vascular infiltration by CD45(+) leukocytes.Elevated plasma levels of interferon-γ and Cys-X-Cys chemokine receptor 3-binding chemokines are present in patients with thoracic aortic aneurysms. The Cys-X-Cys chemokine receptor 3 receptor is necessary for vascular inflammation and the formation of arterial aneurysms in mice.
View details for DOI 10.1016/j.jtcvs.2011.08.036
View details for PubMedID 21962843
- Acute Liver Failure in a Pediatric Patient with Disseminated Tuberculosis DIGESTIVE DISEASES AND SCIENCES 2011; 56 (10): 2780-2783
- Sclerosing Peritonitis After Kidney Transplantation: A Not-So-Silky Cocoon DIGESTIVE DISEASES AND SCIENCES 2011; 56 (2): 307-310
Interleukin-17 and Interferon-gamma Are Produced Concomitantly by Human Coronary Artery-Infiltrating T Cells and Act Synergistically on Vascular Smooth Muscle Cells
2009; 119 (10): 1424-1432
Atherosclerosis is an inflammatory disease in which interferon (IFN)-gamma, the signature cytokine of Th1 cells, plays a central role. We investigated whether interleukin (IL)-17, the signature cytokine of Th17 cells, is also associated with human coronary atherosclerosis.Circulating IL-17 and IFN-gamma were detected in a subset of patients with coronary atherosclerosis and in referent outpatients of similar age without cardiac disease but not in young healthy individuals. IL-17 plasma levels correlated closely with those of the IL-12/IFN-gamma/CXCL10 cytokine axis but not with known Th17 inducers such as IL-1beta, IL-6, and IL-23. Both IL-17 and IFN-gamma were produced at higher levels by T cells within cultured atherosclerotic coronary arteries after polyclonal activation than within nondiseased vessels. Combinations of proinflammatory cytokines induced IFN-gamma but not IL-17 secretion. Blockade of IFN-gamma signaling increased IL-17 synthesis, whereas neutralization of IL-17 responses decreased IFN-gamma synthesis; production of both cytokines was inhibited by transforming growth factor-beta1. Approximately 10-fold fewer coronary artery-infiltrating T helper cells were IL-17 producers than IFN-gamma producers, and unexpectedly, IL-17/IFN-gamma double producers were readily detectable within the artery wall. Although IL-17 did not modulate the growth or survival of cultured vascular smooth muscle cells, IL-17 interacted cooperatively with IFN-gamma to enhance IL-6, CXCL8, and CXCL10 secretion.Our findings demonstrate that IL-17 is produced concomitantly with IFN-gamma by coronary artery-infiltrating T cells and that these cytokines act synergistically to induce proinflammatory responses in vascular smooth muscle cells.
View details for DOI 10.1161/CIRCULATIONAHA.108.827618
View details for Web of Science ID 000264243700011
View details for PubMedID 19255340
The role of surgery in the treatment of stage III non-small-cell lung cancer.
Current oncology reports
2007; 9 (4): 247-254
Stage III, locally advanced non-small-cell lung cancer represents an incredibly heterogeneous group of patients. The majority of patients are treated with curative intent, but optimal therapy is controversial and the role of surgery is not well defined. Consensus has shown that the majority of patients with IIIB disease are not amenable to resection. The exceptions are selected patients with tumor stage 4 (T4) by virtue of a satellite nodule or those with isolated invasion of the spine, superior sulcus, carina, or vena cava. Surgery is more widely used for stage IIIA disease. Patients with nodal stage 2 (N2) disease represent the largest population of patients in stage III. Increasing evidence supports the use of surgery as part of a multimodality approach for N2 disease. The impact of surgery is partially determined by the bulk of the mediastinal node involvement. Patients with micrometastatic disease and single-station nodal involvement have the greatest chance for cure, and surgery appears to play a significant role in their treatment. Patients with bulky multistation disease are frequently not amenable to complete resection and may be best approached with definitive chemotherapy and radiation. In addition, the ability to sterilize mediastinal lymph nodes with induction therapy correlates strongly with survival following resection, but the ideal induction regime that balances the safety and efficacy has yet to be determined.
View details for PubMedID 17588348
- What is the optimal management of late-presenting survivors of acute type A aortic dissection? 42nd Annual Meeting of the Society-of-Thoracic-Surgeons ELSEVIER SCIENCE INC. 2007: 1593–1602
Thoracic Surgery Directors Association Award. What is the optimal management of late-presenting survivors of acute type A aortic dissection?
Annals of thoracic surgery
2007; 83 (5): 1593-1601
Although type A aortic dissections represent a surgical emergency, some patients present late after the onset of symptoms. Optimal management of this cohort has not been defined.Data on 195 patients with type A dissections followed up at a single institution between 1985 and 2005 were collected prospectively. Of these, 93 patients (47.2%) presented 48 hours or later after the initial onset of pain (group A), and the remaining 102 patients underwent immediate operative repair (group B). Median follow-up was 41.8 months (range, 0 to 386 months).Patients in group A were older (68.8 versus 59.3 years, p = 0.0005) and had a higher incidence of coronary artery disease (42.5% versus 14.6%, p < 0.0001), pulmonary disease (26.6% versus 8.4%, p = 0.0023), and congestive heart failure (14.1% versus 1.0%, p = 0.0004). Long-term survival was similar, although group B showed a trend toward improved 30-day mortality (16.5% versus 8.7%, p = 0.1035). Of the 92 patients in group A, 53 (57.6%) eventually underwent operative repair a median of 8.2 days after symptom onset. There was a trend toward improved long-term survival among patients undergoing repair (p = 0.1031).Initial medical management with interval operative repair of selected patients referred greater than 2 days following an acute type A dissection is a viable option. Delayed repair after optimization of the clinical condition and detailed evaluation of concomitant diseases results in excellent long-term results.
View details for PubMedID 17462364
Natural history of ascending aortic aneurysms in the setting of an unreplaced bicuspid aortic valve
42nd Annual Meeting of the Society-of-Thoracic-Surgeons
ELSEVIER SCIENCE INC. 2007: 1338–44
Patients with bicuspid aortic valve (BAV) are at risk for valvular disease and ascending aortic aneurysms and dissections. Although others have investigated the need for concomitant repair, the natural history of aortic disease has not been addressed.A review of our institutional clinical database identified 514 patients (326 male, 188 female) with unrepaired ascending aortic aneurysms followed from 1985 to 2005. Seventy patients (13.4%) diagnosed with BAV form group A; the remaining 445 patients form group B. Growth rates and risk factors for complications were assessed.Patients in group A had a lower incidence of hypertension (p = 0.0185), carotid artery disease, and stroke (p = 0.0184), and presented at an earlier age (49.0 versus 64.2 years, p < 0.0001). Group A also had a higher rate of aortic growth (0.19 versus 0.13 cm/year, p = 0.0102). The incidence of rupture and dissection were similar. Overall survival was better among patients with BAV (p < 0.0001). Among patients with BAV, those with aortic stenosis had a higher risk of rupture, dissection, or death before operative repair than did those with normally functioning valves (odds ratio 10.475, 95% confidence interval: 1.153 to 95.155).Aortic stenosis presents a significant added risk for patients with aneurysmal disease in the face of BAV. Despite faster rates of growth, however, patients with BAV have similar rates of aortic rupture, dissection, and death and improved long-term survival. Contributing to this finding may be the lower incidence of comorbidities, the younger age at presentation, and the more attentive follow-up with earlier operative repair.
View details for DOI 10.1016/j.athoracsur.2006.10.074
View details for Web of Science ID 000245178900017
View details for PubMedID 17383337
An inflammatory pathway of IFN-gamma production in coronary atherosclerosis
JOURNAL OF IMMUNOLOGY
2007; 178 (1): 592-604
Inflammation is associated with the pathogenesis of coronary atherosclerosis, although the mechanisms remain unclear. We investigated whether cytokine secretion by innate immune responses could contribute to the production of proarteriosclerotic Th1-type cytokines in human coronary atherosclerosis. Cytokines were measured by ELISA in the plasma of patients with coronary atherosclerosis undergoing cardiac catheterization. IL-18 was detected in all subjects, whereas a subset of patients demonstrated a coordinated induction of other IFN-gamma-related cytokines. Specifically, elevated plasma levels of IL-12 correlated with that of IFN-gamma and IFN-gamma-inducible chemokines, defining an IFN-gamma axis that was activated independently of IL-6 or C-reactive protein. Systemic inflammation triggered by cardiopulmonary bypass increased plasma levels of the IFN-gamma axis, but not that of IL-18. Activation of the IFN-gamma axis was not associated with acute coronary syndromes, but portended increased morbidity and mortality after 1-year follow-up. IL-12 and IL-18, but not other monokines, elicited secretion of IFN-gamma and IFN-gamma-inducible chemokines in human atherosclerotic coronary arteries maintained in organ culture. T cells were the principal source of IFN-gamma in response to IL-12/IL-18 within the arterial wall. This inflammatory response did not require, but was synergistic with and primed for TCR signals. IL-12/IL-18-stimulated T cells displayed a cytokine-producing, nonproliferating, and noncytolytic phenotype, consistent with previous descriptions of lymphocytes in stable plaques. In contrast to cognate stimuli, IL-12/IL-18-dependent IFN-gamma secretion was prevented by a p38 MAPK inhibitor and not by cyclosporine. In conclusion, circulating IL-12 may provide a mechanistic link between inflammation and Th1-type cytokine production in coronary atherosclerosis.
View details for Web of Science ID 000243120900067
View details for PubMedID 17182600
Indications, timing, and prognosis of operative repair of aortic dissections.
Seminars in thoracic and cardiovascular surgery
2005; 17 (3): 224-235
Since the first description of aortic dissection in the 1700s, the understanding and treatment of this catastrophic disease has evolved. Aortic dissections are identified as a tear in the aortic intima and inner layer of the media that allows for blood flow within the aortic wall. The area of the vessel involved determines its classification. The classification, in turn, helps to predict outcomes, which allows for appropriate treatment planning. The goal of this article is to outline the operative indications and timing for Stanford type A and type B dissections, based on prior reported data and our own clinical experience with 176 patients treated surgically at the Yale Center for Thoracic Aortic Disease. With this data we will revisit the importance of looking at each patient individually to devise an appropriate operative plan, with the knowledge that treatment for type A dissections is operative and treatment for type B dissections is medical unless patients present with actual or impending rupture, malperfusion, or failure of medical management.
View details for PubMedID 16253827
A novel protein complex distinct from mismatch repair binds thioguanylated DNA
2001; 59 (2): 367-374
To elucidate molecular mechanism(s) of cellular response to mercaptopurine, a widely used antileukemic agent, we assessed mercaptopurine (MP) sensitivity in mismatch repair (MMR) proficient and MMR deficient human acute lymphoblastic leukemia (ALL) cells. Sensitivity to thiopurine cytotoxicity was not dependent on MMR (i.e., MutSalpha) competence among six cell lines tested. Using electrophoretic mobility shift assay analysis, we found that the incubation of nuclear extracts from ALL cells with synthetic 34-mer DNA duplexes containing deoxythioguanosine (G(S)) within either G(S).T or G(S).C pairs, resulted in formation of a DNA-protein complex distinct from the DNA-MutSalpha complex and unaffected by ATP. Isolation and sequence analysis of proteins involved in this DNA-protein complex identified glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as a component. Western blot analysis of nuclear extracts from a panel of human lymphoblastic leukemia cell lines revealed markedly different basal levels of GAPDH in nuclei, which was significantly related to thiopurine sensitivity (p = 0.001). Confocal analysis revealed markedly different intracellular distribution of GAPDH between nucleus and cytosol in six human ALL cell lines. Redistribution of GAPDH from cytosol to nucleus was evident after MP treatment. These findings indicate that a new DNA-protein complex containing GAPDH and distinct from known MMR protein-DNA complexes binds directly to thioguanylated DNA, suggesting that this may act as a sensor of structural alterations in DNA and serve as an interface between these DNA modifications and apoptosis.
View details for Web of Science ID 000166549200026
View details for PubMedID 11160874