Bio

Professional Education


  • Fellowship, Stanford University, Hematology-Oncology
  • Residency, Columbia University, Medical Center, Internal Medicine (2011)
  • MD, University of California, Los Angeles, Medicine (2008)
  • BS, University of California, Los Angeles, Molecular, Cell, Developmental Biology (2003)

Stanford Advisors


Research & Scholarship

Lab Affiliations


Publications

Journal Articles


  • A Phase I Dose-Finding Study of Silybin Phosphatidylcholine (Milk Thistle) in Patients With Advanced Hepatocellular Carcinoma INTEGRATIVE CANCER THERAPIES Siegel, A. B., Narayan, R., Rodriguez, R., Goyal, A., Jacobson, J. S., Kelly, K., Ladas, E., Lunghofer, P. J., Hansen, R. J., Gustafson, D. L., Flaig, T. W., Tsai, W. Y., Wu, D. P., Lee, V., Greenlee, H. 2014; 13 (1): 46-53

    Abstract

    . To determine the maximum tolerated dose per day of silybin phosphatidylcholine (Siliphos) in patients with advanced hepatocellular carcinoma (HCC) and hepatic dysfunction.. Patients with advanced HCC not eligible for other therapies based on poor hepatic function were enrolled in a phase I study of silybin phosphatidylcholine. A standard phase I design was used with 4 planned cohorts, dose escalating from 2, 4, 8, to 12 g per day in divided doses for 12 weeks.. Three participants enrolled in this single institution trial. All enrolled subjects consumed 2 g per day of study agent in divided doses. Serum concentrations of silibinin and silibinin glucuronide increased within 1 to 3 weeks. In all 3 patients, liver function abnormalities and tumor marker α-fetoprotein progressed, but after day 56 the third patient showed some improvement in liver function abnormalities and inflammatory biomarkers. All 3 participants died within 23 to 69 days of enrolling into the trial, likely from hepatic failure, but it could not be ruled out that deaths were possibly due to the study drug.. Short-term administration of silybin phosphatidylcholine in patients with advanced HCC resulted in detectable increases in silibinin and its metabolite, silibinin glucuronide. The maximum tolerated dose could not be established. Since patients died soon after enrollment, this patient population may have been too ill to benefit from an intervention designed to improve liver function tests.

    View details for DOI 10.1177/1534735413490798

    View details for Web of Science ID 000330774000005

    View details for PubMedID 23757319

  • Multiple clinical forms of dehydrated hereditary stomatocytosis arise from mutations in PIEZO1 BLOOD Andolfo, I., Alper, S. L., De Franceschi, L., Auriemma, C., Russo, R., De Falco, L., Vallefuoco, F., Esposito, M. R., Vandorpe, D. H., Shmukler, B. E., Narayan, R., Montanaro, D., D'Armiento, M., Vetro, A., Limongelli, I., Zuffardi, O., Glader, B. E., Schrier, S. L., Brugnara, C., Stewart, G. W., Delaunay, J., Iolascon, A. 2013; 121 (19): 3925-3935

    Abstract

    Autosomal dominant dehydrated hereditary stomatocytosis (DHSt) usually presents as a compensated hemolytic anemia with macrocytosis and abnormally shaped red blood cells (RBCs). DHSt is part of a pleiotropic syndrome that may also exhibit pseudohyperkalemia and perinatal edema. We identified PIEZO1 as the disease gene for pleiotropic DHSt in a large kindred by exome sequencing analysis within the previously mapped 16q23-q24 interval. In 26 affected individuals among 7 multigenerational DHSt families with the pleiotropic syndrome, 11 heterozygous PIEZO1 missense mutations cosegregated with disease. PIEZO1 is expressed in the plasma membranes of RBCs and its messenger RNA, and protein levels increase during in vitro erythroid differentiation of CD34(+) cells. PIEZO1 is also expressed in liver and bone marrow during human and mouse development. We suggest for the first time a correlation between a PIEZO1 mutation and perinatal edema. DHSt patient red cells with the R2456H mutation exhibit increased ion-channel activity. Functional studies of PIEZO1 mutant R2488Q expressed in Xenopus oocytes demonstrated changes in ion-channel activity consistent with the altered cation content of DHSt patient red cells. Our findings provide direct evidence that R2456H and R2488Q mutations in PIEZO1 alter mechanosensitive channel regulation, leading to increased cation transport in erythroid cells.

    View details for DOI 10.1182/blood-2013-02-482489

    View details for Web of Science ID 000321870900023

    View details for PubMedID 23479567

  • Killed but Metabolically Active Leishmania infantum as a Novel Whole-Cell Vaccine for Visceral Leishmaniasis CLINICAL AND VACCINE IMMUNOLOGY Bruhn, K. W., Birnbaum, R., Haskell, J., Vanchinathan, V., Greger, S., Narayan, R., Chang, P., Thu Anh Tran, T. A., Hickerson, S. M., Beverley, S. M., Wilson, M. E., Craft, N. 2012; 19 (4): 490-498

    Abstract

    There are currently no effective vaccines for visceral leishmaniasis, the second most deadly parasitic infection in the world. Here, we describe a novel whole-cell vaccine approach using Leishmania infantum chagasi promastigotes treated with the psoralen compound amotosalen (S-59) and low doses of UV A radiation. This treatment generates permanent, covalent DNA cross-links within parasites and results in Leishmania organisms termed killed but metabolically active (KBMA). In this report, we characterize the in vitro growth characteristics of both KBMA L. major and KBMA L. infantum chagasi. Concentrations of S-59 that generate optimally attenuated parasites were identified. Like live L. infantum chagasi, KBMA L. infantum chagasi parasites were able to initially enter liver cells in vivo after intravenous infection. However, whereas live L. infantum chagasi infection leads to hepatosplenomegaly in mice after 6 months, KBMA L. infantum chagasi parasites were undetectable in the organs of mice at this time point. In vitro, KBMA L. infantum chagasi retained the ability to enter macrophages and induce nitric oxide production. These characteristics of KBMA L. infantum chagasi correlated with the ability to prophylactically protect mice via subcutaneous vaccination at levels similar to vaccination with live, virulent organisms. Splenocytes from mice vaccinated with either live L. infantum chagasi or KBMA L. infantum chagasi displayed similar cytokine patterns in vitro. These results suggest that KBMA technology is a potentially safe and effective novel vaccine strategy against the intracellular protozoan L. infantum chagasi. This approach may represent a new method for whole-cell vaccination against other complex intracellular pathogens.

    View details for DOI 10.1128/CVI.05660-11

    View details for Web of Science ID 000302156700004

    View details for PubMedID 22323556

  • Immunomodulation by Imiquimod in Patients with High-Risk Primary Melanoma JOURNAL OF INVESTIGATIVE DERMATOLOGY Narayan, R., Nguyen, H., Bentow, J. J., Moy, L., Lee, D. K., Greger, S., Haskell, J., Vanchinathan, V., Chang, P., Tsui, S., Konishi, T., Comin-Anduix, B., Dauphine, C., Vargas, H. I., Economou, J. S., Ribas, A., Bruhn, K. W., Craft, N. 2012; 132 (1): 163-169

    Abstract

    Imiquimod is a synthetic Toll-like receptor 7 (TLR7) agonist approved for the topical treatment of actinic keratoses, superficial basal cell carcinoma, and genital warts. Imiquimod leads to an 80-100% cure rate of lentigo maligna; however, studies of invasive melanoma are lacking. We conducted a pilot study to characterize the local, regional, and systemic immune responses induced by imiquimod in patients with high-risk melanoma. After treatment of the primary melanoma biopsy site with placebo or imiquimod cream, we measured immune responses in the treated skin, sentinel lymph nodes (SLNs), and peripheral blood. Treatment of primary melanomas with 5% imiquimod cream was associated with an increase in both CD4+ and CD8+ T cells in the skin, and CD4+ T cells in the SLN. Most of the CD8+ T cells in the skin were CD25 negative. We could not detect any increases in CD8+ T cells specifically recognizing HLA-A(*)0201-restricted melanoma epitopes in the peripheral blood. The findings from this small pilot study demonstrate that topical imiquimod treatment results in enhanced local and regional T-cell numbers in both the skin and SLN. Further research into TLR7 immunomodulating pathways as a basis for effective immunotherapy against melanoma in conjunction with surgery is warranted.

    View details for DOI 10.1038/jid.2011.247

    View details for Web of Science ID 000298237000024

    View details for PubMedID 21850019

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