Bio

Clinical Focus


  • Cardiovascular Disease

Administrative Appointments


  • Chief Resident, Medicine Residency Program (2005 - 2006)

Honors & Awards


  • Professionalism Award, Stanford Medicine Residency Program (2004)

Education & Certifications


  • Fellowship:Massachusetts General Hospital Cardiology Fellowship (2013) MA
  • Fellowship:Brigham and Women's Hospital Harvard Medical School (2014) MA
  • Residency:Stanford University Medical Center (2006) CA
  • Internship:Stanford University Medical Center (2003) CA
  • Medical Education:Duke University School of Medicine (2002) NC
  • Board Certification: Cardiovascular Disease, American Board of Internal Medicine (2009)
  • BA, Columbia College, NY, Biology (1997)
  • Board Certification: Internal Medicine, American Board of Internal Medicine (2005)
  • MD, Duke Univ School of Medicine, Medicine (2002)
  • Residency, Stanford Univ Medical Center, Medicine (2005)

Publications

All Publications


  • A resident-created hospitalist curriculum for internal medicine housestaff. Journal of hospital medicine Kumar, A., Smeraglio, A., Witteles, R., Harman, S., Nallamshetty, S., Rogers, A., Harrington, R., Ahuja, N. 2016; 11 (9): 646-649

    Abstract

    The growth of hospital medicine has led to new challenges, and recent graduates may feel unprepared to meet the expanding clinical duties expected of hospitalists. At our institution, we created a resident-inspired hospitalist curriculum to address the training needs for the next generation of hospitalists. Our program provided 3 tiers of training: (1) clinical excellence through improved training in underemphasized areas of hospital medicine, (2) academic development through required research, quality improvement, and medical student teaching, and (3) career mentorship. In this article, we describe the genesis of our program, our final product, and the challenges of creating a curriculum while being internal medicine residents. Journal of Hospital Medicine 2016. © 2016 Society of Hospital Medicine.

    View details for DOI 10.1002/jhm.2590

    View details for PubMedID 27079160

  • Increased Risk of Progression of Coronary Artery Calcification in Male Subjects with High Baseline Waist-to-Height Ratio: The Kangbuk Samsung Health Study. Diabetes & metabolism journal Oh, H. G., Nallamshetty, S., Rhee, E. J. 2016; 40 (1): 54-61

    Abstract

    The waist-to-height ratio (WHtR) is an easy and inexpensive adiposity index that reflects central obesity. In this study, we examined the association of baseline WHtR and progression of coronary artery calcification (CAC) over 4 years of follow-up in apparently healthy Korean men.A total of 1,048 male participants (mean age, 40.9 years) in a health-screening program in Kangbuk Samsung Hospital, Seoul, Korea who repeated a medical check-up in 2010 and 2014 were recruited. Baseline WHtR was calculated using the value for the waist in 2010 divided by the value for height in 2010. The CAC score (CACS) of each subject was measured by multi-detector computed tomography in both 2010 and 2014. Progression of CAC was defined as a CACS change over 4 years greater than 0.During the follow-up period, progression of CAC occurred in 278 subjects (26.5%). The subjects with CAC progression had slightly higher but significant baseline WHtR compared to those who did not show CAC progression (0.51±0.04 vs. 0.50±0.04, P<0.01). The proportion of subjects with CAC progression significantly increased as the baseline WHtR increased from the 1st quartile to 4th quartile groups (18.3%, 18.7%, 28.8%, and 34.2%; P<0.01). The risk for CAC progression was elevated with an odds ratio of 1.602 in the 4th quartile group of baseline WHtR even after adjustment for confounding variables (95% confidence interval, 1.040 to 2.466).Increased baseline WHtR was associated with increased risk for CAC progression. WHtR might be a useful screening tool to identify individuals at high risk for subclinical atherosclerosis.

    View details for DOI 10.4093/dmj.2016.40.1.54

    View details for PubMedID 26912156

  • Transcriptional profiling of in vitro smooth muscle cell differentiation identifies specific patterns of gene and pathway activation PHYSIOLOGICAL GENOMICS Spin, J. M., Nallamshetty, S., Tabibiazar, R., Ashley, E. A., King, J. Y., Chen, M., Tsao, P. S., Quertermous, T. 2004; 19 (3): 292-302

    Abstract

    Mesodermal and epidermal precursor cells undergo phenotypic changes during differentiation to the smooth muscle cell (SMC) lineage that are relevant to pathophysiological processes in the adult. Molecular mechanisms that underlie lineage determination and terminal differentiation of this cell type have received much attention, but the genetic program that regulates these processes has not been fully defined. Study of SMC differentiation has been facilitated by development of the P19-derived A404 embryonal cell line, which differentiates toward this lineage in the presence of retinoic acid and allows selection for cells adopting a SMC fate through a differentiation-specific drug marker. We sought to define global alterations in gene expression by studying A404 cells during SMC differentiation with oligonucleotide microarray transcriptional profiling. Using an in situ 60-mer array platform with more than 20,000 mouse genes derived from the National Institute on Aging clone set, we identified 2,739 genes that were significantly upregulated after differentiation was completed (false-detection ratio <1). These genes encode numerous markers known to characterize differentiated SMC, as well as many unknown factors. We further characterized the sequential patterns of gene expression during the differentiation time course, particularly for known transcription factor families, providing new insights into the regulation of the differentiation process. Changes in genes associated with specific biological ontology-based pathways were evaluated, and temporal trends were identified for functional pathways. In addition to confirming the utility of the A404 model, our data provide a large-scale perspective of gene regulation during SMC differentiation.

    View details for DOI 10.1152/physiolgenomics.00148.2004

    View details for Web of Science ID 000225840800007

    View details for PubMedID 15340120

  • A growth factor-dependent nuclear kinase phosphorylates p27(Kip1) and regulates cell cycle progression EMBO JOURNAL Boehm, M., Yoshimoto, T., Crook, M. F., Nallamshetty, S., True, A., Nabel, G. J., Nabel, E. G. 2002; 21 (13): 3390-3401

    Abstract

    The cyclin-dependent kinase inhibitor, p27(Kip1), which regulates cell cycle progression, is controlled by its subcellular localization and subsequent degradation. p27(Kip1) is phosphorylated on serine 10 (S10) and threonine 187 (T187). Although the role of T187 and its phosphorylation by Cdks is well-known, the kinase that phosphorylates S10 and its effect on cell proliferation has not been defined. Here, we identify the kinase responsible for S10 phosphorylation as human kinase interacting stathmin (hKIS) and show that it regulates cell cycle progression. hKIS is a nuclear protein that binds the C-terminal domain of p27(Kip1) and phosphorylates it on S10 in vitro and in vivo, promoting its nuclear export to the cytoplasm. hKIS is activated by mitogens during G(0)/G(1), and expression of hKIS overcomes growth arrest induced by p27(Kip1). Depletion of KIS using small interfering RNA (siRNA) inhibits S10 phosphorylation and enhances growth arrest. p27(-/-) cells treated with KIS siRNA grow and progress to S/G(2 )similar to control treated cells, implicating p27(Kip1) as the critical target for KIS. Through phosphorylation of p27(Kip1) on S10, hKIS regulates cell cycle progression in response to mitogens.

    View details for Web of Science ID 000176784100018

    View details for PubMedID 12093740

  • Coexpression of guanylate kinase with thymidine kinase enhances prodrug cell killing in vitro and suppresses vascular smooth muscle cell proliferation in vivo MOLECULAR THERAPY Akyurek, L. M., Nallamshetty, S., Aoki, K., San, H., Yang, Z. Y., Nabel, G. J., Nabel, E. G. 2001; 3 (5): 779-786

    Abstract

    Herpes simplex virus-thymidine kinase (HSV-TK) phosphorylates the prodrugs ganciclovir (GCV) and acyclovir (ACV), leading to disruption of DNA synthesis and inhibition of cell proliferation. HSV-TK vectors have been successfully employed in cardiovascular and cancer gene therapy. Activation of GCV and ACV, after an initial phosphorylation step by the viral thymidine kinase, is carried out by guanylate kinase. We reasoned that coexpression of guanylate kinase (GK) with HSV-TK would augment phosphorylation of GCV or ACV, leading to increased cell killing. To test this hypothesis, a vector expressing TK with GK (TKciteGK) was developed and tested on vascular smooth muscle cells (vsmcs) in vitro and in vivo. Compared to HSV-TK vectors, killing of vascular cells transduced with TKciteGK and exposed to GCV was significantly increased (P = 0.03). The TKciteGK construct was evaluated with three promoters: CMV, EF1alpha, and SM22alpha. TKciteGK expression driven by a CMV promoter induced cell killing more effectively than SM22alpha or EF1alpha promoters in primary vsmcs. Based upon these in vitro findings, TKciteGK vectors with a CMV promoter were tested in two animal models of cardiovascular disease: balloon angioplasty and stent deployment in pig arteries. Following vascular injury, expression of CMV-TKciteGK with GCV significantly reduced vsmc proliferation and intimal lesion formation compared to control vectors with GCV. In the angioplasty model, there was an 80% reduction in intima-to-media area ratio (P = 0.0002). These findings were paralleled in a stent model with 66% reduction in intimal lesions (P = 0.006). Coexpression of GK with TK increases cell killing and permits administration of GCV at lower doses. These modifications in TKciteGK vectors and GCV showed enhanced efficacy at lower prodrug doses, leading to improved safety for cardiovascular gene therapy.

    View details for Web of Science ID 000168924400016

    View details for PubMedID 11356082