All Publications

  • A novel platform for isotype-specific testing of autoantibodies. PloS one Carter, K. L., Treurnicht, A., Davis, K. L., Kumar, R. B., Feldman, B. J. 2019; 14 (2): e0211596


    The objective of this study was to test if a novel platform could be used for isotype-specific autoantibody testing in humans. Further, we evaluated if testing with this novel platform enables earlier detection of insulin autoantibodies in individuals that have first-degree relatives with type-1 diabetes than currently used approaches. Longitudinal serum samples from participants were collected before and after they converted to become positive for insulin autoantibodies by the current standardly used assays. Using a novel plasmonic gold chip platform, we tested these samples for IgM isotype-specific autoantibodies. Serial serum samples from individuals without diabetes were also tested as a comparison control cohort. Our results demonstrate proof-of-concept that a plasmonic gold chip can specifically detect the IgM insulin autoantibody. Five out of the six individuals that converted to being positive for insulin autoantibodies by standard testing had significant IgM autoantibodies on the plasmonic chip platform. The plasmonic chip platform detected IgM autoantibodies earlier than standard testing by up to 4 years. Our results indicate that the plasmonic gold platform can specifically detect the IgM isotype autoantibodies and suggest that combining isotype-specific testing with currently used approaches enables earlier detection of insulin autoantibodies in individuals that have first-degree relatives with type 1 diabetes.

    View details for DOI 10.1371/journal.pone.0211596

    View details for PubMedID 30730939

  • Salivary cortisol levels by tandem mass spectrometry during high dose ACTH stimulation test for adrenal insufficiency in children. Endocrine Chao, C. S., Shi, R. Z., Kumar, R. B., Aye, T. n. 2019


    Serum cortisol measurements after ACTH stimulation are currently used to evaluate for adrenal insufficiency in children. We aim to determine if salivary cortisol measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) can confirm or replace serum cortisol during high dose ACTH stimulation test to improve test compliance and interpretation. We also aim to gain preliminary understanding of normal ranges of salivary cortisol in normal children at am, bedtime, and midnight.Children aged 6-17 years meeting study criteria and tested for adrenal insufficiency were recruited to concomitantly collect saliva and serum samples during high dose ACTH stimulation test. Normal children aged 3-18 years were recruited to collect morning, bedtime, and midnight saliva samples. Salivary cortisol was measured using LC-MS/MS while serum cortisol was determined by an immunoassay.Salivary cortisol in normal children were higher at am and lower at bedtime and midnight (p value <0.0002 and <0.007, respectively). The midnight and bedtime levels were not sufficiently different (p value 0.36). Salivary cortisol during ACTH stimulation test positively and closely correlated with serum cortisol with 100% specificity and sensitivity when 18 µg/dL for serum and 500 ng/dL for salivary cortisol were used as cutoff values respectively for adrenal sufficiency.Measurement of salivary cortisol by LC-MS/MS is less invasive, more convenient and better time controlled in busy pediatric clinic, therefore is better suited for young children to be used during high dose ACTH stimulation test to evaluate for adrenal insufficiency and to assist interpretation of test results by serum cortisol.

    View details for DOI 10.1007/s12020-019-02084-8

    View details for PubMedID 31535345

  • Automated integration of continuous glucose monitor data in the electronic health record using consumer technology. Journal of the American Medical Informatics Association Kumar, R. B., Goren, N. D., Stark, D. E., Wall, D. P., Longhurst, C. A. 2016; 23 (3): 532-537


    The diabetes healthcare provider plays a key role in interpreting blood glucose trends, but few institutions have successfully integrated patient home glucose data in the electronic health record (EHR). Published implementations to date have required custom interfaces, which limit wide-scale replication. We piloted automated integration of continuous glucose monitor data in the EHR using widely available consumer technology for 10 pediatric patients with insulin-dependent diabetes. Establishment of a passive data communication bridge via a patient's/parent's smartphone enabled automated integration and analytics of patient device data within the EHR between scheduled clinic visits. It is feasible to utilize available consumer technology to assess and triage home diabetes device data within the EHR, and to engage patients/parents and improve healthcare provider workflow.

    View details for DOI 10.1093/jamia/ocv206

    View details for PubMedID 27018263

  • The Quantified Brain: A Framework for Mobile Device-Based Assessment of Behavior and Neurological Function. Applied clinical informatics Stark, D. E., Kumar, R. B., Longhurst, C. A., Wall, D. P. 2016; 7 (2): 290–98

    View details for PubMedID 27437041

  • "Big Data" in Laboratory Medicine. Clinical chemistry Tolan, N. V., Parnas, M. L., Baudhuin, L. M., Cervinski, M. A., Chan, A. S., Holmes, D. T., Horowitz, G., Klee, E. W., Kumar, R. B., Master, S. R. 2015; 61 (12): 1433-1440

    View details for DOI 10.1373/clinchem.2015.248591

    View details for PubMedID 26487761

  • The development of next-generation screening and diagnostic platforms will change diabetes care. Expert review of molecular diagnostics Kumar, R. B., Gupta, M., Feldman, B. J. 2015; 15 (3): 291-294


    Diabetes mellitus is a common disease with a rising incidence and the findings of hyperglycemia and glucosuria. However, there are multiple types of diabetes, each with distinct etiologies. The two major types of diabetes are type 1, which is caused by an autoimmune process, and type 2, which is thought to be primarily metabolic, resulting from insulin resistance, often in the setting of obesity. Historically, the distinction between these two types was obvious. Here, we discuss how this paradigm has dramatically changed because of both the evolving epidemiology of diabetes mellitus and new and emerging tools, and therapies to diagnose and treat diabetes. As we believe that understanding these changes is critical to providing optimal care to patients with diabetes, we have developed a novel plasmonic gold chip platform that is able to meet the new and emerging demands of modern diabetes care.

    View details for DOI 10.1586/14737159.2015.1002468

    View details for PubMedID 25583407

  • Primary ovarian insufficiency in adolescents: a case series. International journal of pediatric endocrinology Pederson, J., Kumar, R. B., Adams Hillard, P. J., Bachrach, L. K. 2015; 2015 (1): 13-?


    Primary ovarian insufficiency (POI) is characterized by 4 to 6 months of amenorrhea and elevated serum FSH and LH in females less than 40 years. Ovarian insufficiency is uncommon in pediatrics and typically results from a chromosomal abnormality or treatment for malignancy. Idiopathic POI in which no apparent precipitant is identified is even rarer. After encountering three teens with idiopathic POI in recent months, we utilized an informatics-enabled search of the electronic medical records from our hospital to identify all cases of idiopathic POI presenting from 1998-2013.15 girls (ages 14.4 to 17.9 years) met criteria for idiopathic POI. At diagnosis, breast development ranged from Tanner stage 1 to 5; 6 of 15 patients had secondary amenorrhea. All patients presented in the past 11 years and 13 of 15 in the past 5 years.In this first case series of POI from the United States, we observed a clustering at our institution in recent years. If an increased incidence of idiopathic POI is identified at other institutions, further investigation into potential environmental and genetic precipitants is warranted.

    View details for DOI 10.1186/s13633-015-0009-z

    View details for PubMedID 25983758

    View details for PubMedCentralID PMC4433018

  • Letrozole vs Anastrozole for Height Augmentation in Short Pubertal Males: First Year Data JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Neely, E. K., Kumar, R. B., Payne, S. L., Ranadive, S. A., Suchet, D. I. 2014; 99 (11): 4086-4093


    Aromatase inhibitors are used off-label to treat short stature in peripubertal boys.To investigate short- and long-term hormonal and auxologic differences in short pubertal boys treated with letrozole (L) or anastrozole (A).PATIENTS are seen for laboratory evaluation and physical examination every 6 months, bone age yearly, DEXA and spine film every 2 years. They will be followed until they reach their final height. This is a preliminary report after 1 year of treatment.A single academic children's hospital outpatient clinic.Boys with age >10 years, bone age ≤ 14 years, clinical and hormonal evidence of central puberty, and either height < fifth percentile or predicted adult height (PAH) more than 10 cm below mid-parental height (MPH).Letrozole (2.5 mg) or anastrozole (1 mg) was administered orally each day.Hormonal and clinical parameters, growth velocity, and change in bone age and PAH.Thirty-nine boys have completed 1 year of treatment. Baseline means were age 14.1 years, PAH 166 cm, and testosterone 198 ng/dL. At 1 year, letrozole resulted in higher LH (L 6.1 ± 2.5 vs A 3.2 ± 1.7 IU/L) and testosterone (1038 ± 348 vs 536 ± 216 ng/dL) with lower estradiol (2.8 ± 2.8 vs 5.6 ± 2.9 pg/mL) and IGF-1 (237 ± 51 vs 331 ± 79 ng/mL). First year growth velocities were identical (7.2 cm/year), but an increase in PAH was greater in the anastrozole group (4.2 ± 3.5 vs 1.4 ± 4.4 cm, p = 0.03) after 1 year.We present first-year data from a direct comparison of anastrozole and letrozole for height augmentation in short pubertal boys. Letrozole was more potent in hormonal manipulation than anastrozole. First-year growth velocities were comparable, but improvement in PAH was greater in the anastrozole group. It remains to be seen if positive PAH trends will translate to increase in final height in either group.

    View details for DOI 10.1210/jc.2014-2432

    View details for PubMedID 25137428

  • A plasmonic chip for biomarker discovery and diagnosis of type 1 diabetes. Nature medicine Zhang, B., Kumar, R. B., Dai, H., Feldman, B. J. 2014; 20 (8): 948-953


    Type 1 diabetes (T1D) is an autoimmune disease, whereas type 2 diabetes (T2D) results from insulin resistance and beta cell dysfunction. Previously, the onset of these two separate diseases was easily distinguished, with children being most at risk for T1D and T2D occurring in overweight adults. However, the dramatic rise in obesity, coupled with the notable increase in T1D, has created a large overlap in these previously discrete patient populations. Delayed diagnosis of T1D can result in severe illness or death, and rapid diagnosis of T1D is critical for the efficacy of emerging therapies. However, attempts to apply next-generation platforms have been unsuccessful for detecting diabetes biomarkers. Here we describe the development of a plasmonic gold chip for near-infrared fluorescence-enhanced (NIR-FE) detection of islet cell-targeting autoantibodies. We demonstrate that this platform has high sensitivity and specificity for the diagnosis of T1D and can be used to discover previously unknown biomarkers of T1D.

    View details for DOI 10.1038/nm.3619

    View details for PubMedID 25038825

  • Annular pancreas in identical twin newborns JOURNAL OF PEDIATRIC SURGERY Kumar, R. B., Hulvat, M. C., Newman, B. M., Muraskas, J. K. 2006; 41 (8)


    Annular pancreas is a rare congenital anomaly occurring in 1 of every 12,000 to 15,000 live births [Nerwich N, Shi E. Neonatal duodenal obstruction: a review of 30 consecutive cases. Pediatr Surg Int 1994;9:47-50]. It may remain asymptomatic throughout life, present in adulthood, or present in infancy as a high intestinal obstruction. Review of the literature demonstrates only 8 cases of familial annular pancreas and no case of twins exhibiting the disease. We will describe a case of identical (monochorionic diamniotic) female twins with neonatal presentation of duodenal obstruction and annular pancreas, and discuss data supportive of a genetic etiology.

    View details for DOI 10.1016/j.jpedsurg.2006.04.028

    View details for Web of Science ID 000239629600037

    View details for PubMedID 16863831