Clinical Focus

  • Internal Medicine

Academic Appointments

  • Clinical Assistant Professor, Medicine

Administrative Appointments

  • Medical Director of Pharmacy, Stanford Healthcare Tri-Valley (2023 - Present)
  • Stanford Tri-Valley Section Chief, Division of Hospital Medicine, Stanford School of Medicine (2023 - Present)
  • Medical Director of Performance Improvement, Stanford Healthcare Tri-Valley (2020 - Present)
  • Director, Internal Medicine Elective Rotation, Stanford Healthcare Tri-Valley (2020 - 2022)

Professional Education

  • Board Certification: American Board of Internal Medicine, Internal Medicine (2019)
  • Residency: Stanford University Internal Medicine Residency (2019) CA
  • Medical Education: University of California at San Francisco School of Medicine (2016) CA
  • Board Certification, American Board of Internal Medicine, Internal Medicine (2019)
  • Residency, Stanford Internal Medicine Residency (2019)
  • MD, UCSF School of Medicine (2016)
  • SB, Massachusetts Institute of Technology, Biological engineering (2012)

All Publications

  • Physicians Leading Physicians: A Physician Engagement Intervention Decreases Inappropriate Use of IICU Level of Care Accommodations. American journal of medical quality : the official journal of the American College of Medical Quality Ruiz Colón, G. n., Yang, J. n., Svec, D. n., Heidenreich, P. n., Britt, P. n., Smith, M. n., Sharp, C. n., Shieh, L. n. 2021


    Following the adoption of an acuity-adaptable unit model in an academic medical center, a $13M increase in cost of intermediate intensive care unit (IICU) accommodations was observed. The authors followed A3 methodology to determine the root cause of this increase and developed a 3-prong intervention centered on physician engagement, given that physicians have the ability to order a patient's level of care. This intervention consisted of: (1) identifying physician champions to promote appropriate IICU use, (2) visual changes to essential electronic medical record tools, and (3) data-driven feedback to physician champions. In the year following intervention deployment, average IICU length of stay decreased from 1.08 to 0.62 days and average IICU use decreased from 21.4% to 12.3%, corresponding to ~$5.7M cost savings with no significant change in balancing measures observed. Together, these results demonstrate that a multicomponent intervention aimed at engaging physicians reduced inappropriate IICU use with no increase in adverse events.

    View details for DOI 10.1097/01.JMQ.0000735480.43566.f9

    View details for PubMedID 33883423

  • Timing and Predictors of Subspecialty Career Choice Among Internal Medicine Residents: A Retrospective Cohort Study. Journal of graduate medical education Yang, J., Singhal, S., Weng, Y., Bentley, J. P., Chari, N., Liu, T., Delgado-Carrasco, K., Ahuja, N., Witteles, R., Kumar, A. 2020; 12 (2): 212-216


    Internal medicine residents face numerous career options after residency training. Little is known about when residents make their final career choice.We assessed the timing and predictive factors of final career choices among internal medicine residents at graduation, including demographics, pre-residency career preferences, and rotation scheduling.We conducted a retrospective study of graduates of an academic internal medicine residency program from 2014 to 2017. Main measures included demographics, rotation schedules, and self-reported career choices for residents at 5 time points: recruitment day, immediately after Match Day, end of postgraduate year 1 (PGY-1), end of PGY-2, and at graduation.Of the 138 residents eligible for the study, 5 were excluded based on participation in a fast-track program for an Accreditation Council for Graduate Medical Education subspecialty fellowship. Among the remaining 133 residents, 48 (36%) pursued general internal medicine fields and 78 (59%) pursued fellowship training. Career choices from recruitment day, Match Day, and PGY-1 were only weakly predictive of the career choice. Many choices demonstrated low concordance throughout training, and general medicine fields (primary care, hospital medicine) were frequently not decided until after PGY-2. Early clinical exposure to subspecialty rotations did not predict final career choice.Early career choices before and during residency training may have low predictability toward final career choices upon graduation in internal medicine. These choices may continue to have low predictability beyond PGY-2 for many specialties. Early clinical exposure may not predict final career choice for subspecialties.

    View details for DOI 10.4300/JGME-D-19-00556.1

    View details for PubMedID 32322356

    View details for PubMedCentralID PMC7161324

  • Atrial Fibrillation Associated Genetic Variants and Left Atrial Histology: Evaluation for Molecular Sub-Phenotypes JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY Roberts, J. D., Yang, J., Gladstone, R. A., Longoria, J., Whitman, I. R., Dewland, T. A., Miller, C., Robles, A., Poon, A., Seiler, B., Laframboise, W. A., Olgin, J. E., Kwok, P., Marcus, G. M. 2016; 27 (11): 1264–70


    Genome wide association studies have identified several single nucleotide polymorphisms (SNPs) associated with atrial fibrillation (AF), but the mechanisms underlying these relationships have not yet been elucidated. Inflammation and fibrosis have been posited as important mechanisms responsible for AF. We sought to investigate the impact of SNP carrier status on inflammation and fibrosis in left atrial appendage tissue.Carrier status of 10 AF-associated SNPs was evaluated on DNA extracted from left atrial appendage tissue in 176 individuals (120 with AF). The presence of inflammation was evaluated through visual quantification of leukocyte infiltration following hematoxylin and eosin staining, while fibrosis was quantified using picrosirius red with fast green staining. Unadjusted and adjusted linear and logistic regression models were utilized to evaluate for an association between SNP carrier status and inflammation and fibrosis. On adjusted logistic regression analysis, the rs7164883 SNP (intronic within HCN4) was associated with a reduced odds of inflammation (odds ratio: 0.42; 95% CI: 0.22-0.81, P = 0.01), and was not associated with fibrosis on adjusted linear regression analysis (β-coefficient: -0.31; 95% CI: -1.03-0.40, P = 0.40). None of the remaining SNPs exhibited significant associations with left atrial inflammation or fibrosis.Among 10 AF-associated SNPs, a single genetic variant was associated with reduced left atrial inflammation, while no histologic differences were observed in the remaining 9. The known AF-associated SNPs do not appear to predispose to the development of pro-inflammatory or pro-fibrotic AF sub-phenotypes.

    View details for DOI 10.1111/jce.13083

    View details for Web of Science ID 000387393800002

    View details for PubMedID 27574037

  • Characteristics of Unselected High-Burden Premature Ventricular Contraction Patients PACE-PACING AND CLINICAL ELECTROPHYSIOLOGY Yang, J., Dudum, R., Mandyam, M. C., Marcus, G. M. 2014; 37 (12): 1671-1680


    High-burden premature ventricular contractions (PVCs) may be an important determinant of heart failure (HF) in patients presenting for PVC ablation. The prevalence and characteristics of high-burden PVC patients outside this setting remain unknown. We, therefore, sought to determine predictors of high-burden PVCs and, among high-burden PVC patients, predictors of HF.We identified all patients undergoing a 24-48-hour Holter study showing at least 20% PVCs between 2005 and 2013 at the University of California, San Francisco. Three time-matched controls undergoing Holter monitoring were selected for each high-burden PVC patient. Medical records were reviewed and test characteristics of PVC counts from 12-lead electrocardiograms (ECG) as predictors of high-burden PVC Holters were analyzed.Among 5,091 participants, 66 (1.3%) exhibited at least 20% PVCs. After multivariate adjustment, high-burden PVC patients had a three-fold greater odds of HF (odds ratio [OR] 3.15; 95% confidence interval [CI] 1.28-6.50; P = 0.005) and 10-fold greater odds of having a first-degree family member with sudden death (OR 9.97; 95% CI 1.78-60.8; P = 0.011). The C-statistic for the number of PVCs on 12-lead electrocardiogram as a predictor of high-burden PVCs was 0.7949. Among high-burden PVC patients, HF was associated with a history of coronary artery bypass grafting (OR 11.76; 95% CI 1.30-106.49; P = 0.028).Among all undergoing Holter monitoring, 1.3% exhibited high-burden PVCs, a phenomenon associated with HF and a first-degree family history of sudden death. In an analysis restricted to high-burden PVC patients, a history of coronary artery bypass grafting was a predictor of HF.

    View details for DOI 10.1111/pace.12476

    View details for Web of Science ID 000345996100012

    View details for PubMedID 25081578

  • Group II archaeal chaperonin recognition of partially folded human γD-crystallin mutants. Protein science : a publication of the Protein Society Sergeeva, O. A., Yang, J., King, J. A., Knee, K. M. 2014; 23 (6): 693-702


    The features in partially folded intermediates that allow the group II chaperonins to distinguish partially folded from native states remain unclear. The archaeal group II chaperonin from Methanococcus Mauripaludis (Mm-Cpn) assists the in vitro refolding of the well-characterized β-sheet lens protein human γD-crystallin (HγD-Crys). The domain interface and buried cores of this Greek key conformation include side chains, which might be exposed in partially folded intermediates. We sought to assess whether particular features buried in the native state, but absent from the native protein surface, might serve as recognition signals. The features tested were (a) paired aromatic side chains, (b) side chains in the interface between the duplicated domains of HγD-Crys, and (c) side chains in the buried core which result in congenital cataract when substituted. We tested the Mm-Cpn suppression of aggregation of these HγD-Crys mutants upon dilution out of denaturant. Mm-Cpn was capable of suppressing the off-pathway aggregation of the three classes of mutants indicating that the buried residues were not recognition signals. In fact, Mm-Cpn recognized the HγD-Crys mutants better than (wild-type) WT and refolded most mutant HγD-Crys to levels twice that of WT HγD-Crys. This presumably represents the increased population or longer lifetimes of the partially folded intermediates of the mutant proteins. The results suggest that Mm-Cpn does not recognize the features of HγD-Crys tested-paired aromatics, exposed domain interface, or destabilized core-but rather recognizes other features of the partially folded β-sheet conformation that are absent or inaccessible in the native state of HγD-Crys.

    View details for DOI 10.1002/pro.2452

    View details for PubMedID 24615724

    View details for PubMedCentralID PMC4093946

  • A novel method for producing mono-biotinylated, biologically active neurotrophic factors: An essential reagent for single molecule study of axonal transport JOURNAL OF NEUROSCIENCE METHODS Sung, K., Maloney, M. T., Yang, J., Wu, C. 2011; 200 (2): 121-128


    In this report, we describe a novel method for producing mature and biologically active mono-biotinylated nerve growth factors (mBtNGF) that can be used for single molecule studies of real-time movement of neurotrophins within axons of neurons. We inserted an AviTag sequence into the C-terminal of the full length mouse preproNGF cDNA and cloned the fusion construct into a pcDNA3.1 mammalian expression vector. We also subcloned the Escherichia coli biotin ligase, BirA, into a pcDNA3.1 vector. These two plasmids were then transiently co-expressed in HEK293FT cells. As a result, the AviTag located in the C-terminal of preproNGF was selectively ligated to a single biotin by BirA. The prepro sequence of NGF was subsequently cleaved within the cell. Mature mono-biotinylated NGF (mBtNGF) was secreted into cell culture media and was purified using Ni resin. We carried out activity assays and our results showed that mBtNGF retained biological activities that were comparable to normal NGF purified from mouse sub maxillary glands. We further verified the biotinylation efficiency of mBtNGF and the level of non-biotinylated NGF was virtually undetectable in the final preparation. Finally, by conjugating to quantum-dot streptavidin, mBtNGF was successfully used for single molecule study of axonal NGF trafficking in neurons.

    View details for DOI 10.1016/j.jneumeth.2011.06.020

    View details for Web of Science ID 000295242300004

    View details for PubMedID 21756937

    View details for PubMedCentralID PMC3158612