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Dive into the research topics where Mark L. Van Natta is active.

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Featured researches published by Mark L. Van Natta.


Hepatology | 2005

Design and validation of a histological scoring system for nonalcoholic fatty liver disease

David E. Kleiner; Elizabeth M. Brunt; Mark L. Van Natta; Cynthia Behling; Melissa J. Contos; Oscar W. Cummings; Linda D. Ferrell; Yao Chang Liu; Michael Torbenson; Aynur Unalp-Arida; Matthew M. Yeh; Arthur J. McCullough; Arun J. Sanyal

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis in the absence of a history of significant alcohol use or other known liver disease. Nonalcoholic steatohepatitis (NASH) is the progressive form of NAFLD. The Pathology Committee of the NASH Clinical Research Network designed and validated a histological feature scoring system that addresses the full spectrum of lesions of NAFLD and proposed a NAFLD activity score (NAS) for use in clinical trials. The scoring system comprised 14 histological features, 4 of which were evaluated semi‐quantitatively: steatosis (0‐3), lobular inflammation (0‐2), hepatocellular ballooning (0‐2), and fibrosis (0‐4). Another nine features were recorded as present or absent. An anonymized study set of 50 cases (32 from adult hepatology services, 18 from pediatric hepatology services) was assembled, coded, and circulated. For the validation study, agreement on scoring and a diagnostic categorization (“NASH,” “borderline,” or “not NASH”) were evaluated by using weighted kappa statistics. Inter‐rater agreement on adult cases was: 0.84 for fibrosis, 0.79 for steatosis, 0.56 for injury, and 0.45 for lobular inflammation. Agreement on diagnostic category was 0.61. Using multiple logistic regression, five features were independently associated with the diagnosis of NASH in adult biopsies: steatosis (P = .009), hepatocellular ballooning (P = .0001), lobular inflammation (P = .0001), fibrosis (P = .0001), and the absence of lipogranulomas (P = .001). The proposed NAS is the unweighted sum of steatosis, lobular inflammation, and hepatocellular ballooning scores. In conclusion, we present a strong scoring system and NAS for NAFLD and NASH with reasonable inter‐rater reproducibility that should be useful for studies of both adults and children with any degree of NAFLD. NAS of ≥5 correlated with a diagnosis of NASH, and biopsies with scores of less than 3 were diagnosed as “not NASH.” (HEPATOLOGY 2005;41:1313–1321.)


The New England Journal of Medicine | 2010

Pioglitazone, Vitamin E, or Placebo for Nonalcoholic Steatohepatitis

Arun J. Sanyal; Naga Chalasani; Kris V. Kowdley; Arthur J. McCullough; Anna Mae Diehl; Nathan M. Bass; Brent A. Neuschwander-Tetri; Joel E. Lavine; James Tonascia; Aynur Unalp; Mark L. Van Natta; Jeanne M. Clark; Elizabeth M. Brunt; David E. Kleiner; Jay H. Hoofnagle; Patricia R. Robuck

BACKGROUND Nonalcoholic steatohepatitis is a common liver disease that can progress to cirrhosis. Currently, there is no established treatment for this disease. METHODS We randomly assigned 247 adults with nonalcoholic steatohepatitis and without diabetes to receive pioglitazone at a dose of 30 mg daily (80 subjects), vitamin E at a dose of 800 IU daily (84 subjects), or placebo (83 subjects), for 96 weeks. The primary outcome was an improvement in histologic features of nonalcoholic steatohepatitis, as assessed with the use of a composite of standardized scores for steatosis, lobular inflammation, hepatocellular ballooning, and fibrosis. Given the two planned primary comparisons, P values of less than 0.025 were considered to indicate statistical significance. RESULTS Vitamin E therapy, as compared with placebo, was associated with a significantly higher rate of improvement in nonalcoholic steatohepatitis (43% vs. 19%, P=0.001), but the difference in the rate of improvement with pioglitazone as compared with placebo was not significant (34% and 19%, respectively; P=0.04). Serum alanine and aspartate aminotransferase levels were reduced with vitamin E and with pioglitazone, as compared with placebo (P<0.001 for both comparisons), and both agents were associated with reductions in hepatic steatosis (P=0.005 for vitamin E and P<0.001 for pioglitazone) and lobular inflammation (P=0.02 for vitamin E and P=0.004 for pioglitazone) but not with improvement in fibrosis scores (P=0.24 for vitamin E and P=0.12 for pioglitazone). Subjects who received pioglitazone gained more weight than did those who received vitamin E or placebo; the rates of other side effects were similar among the three groups. CONCLUSIONS Vitamin E was superior to placebo for the treatment of nonalcoholic steatohepatitis in adults without diabetes. There was no benefit of pioglitazone over placebo for the primary outcome; however, significant benefits of pioglitazone were observed for some of the secondary outcomes. (ClinicalTrials.gov number, NCT00063622.)


The Lancet | 2015

Farnesoid X nuclear receptor ligand obeticholic acid for non-cirrhotic, non-alcoholic steatohepatitis (FLINT): a multicentre, randomised, placebo-controlled trial

Brent A. Neuschwander-Tetri; Rohit Loomba; Arun J. Sanyal; Joel E. Lavine; Mark L. Van Natta; Manal F. Abdelmalek; Naga Chalasani; Srinivasan Dasarathy; Anna Mae Diehl; Bilal Hameed; Kris V. Kowdley; Arthur J. McCullough; Norah A. Terrault; Jeanne M. Clark; James Tonascia; Elizabeth M. Brunt; David E. Kleiner; Edward Doo

BACKGROUND The bile acid derivative 6-ethylchenodeoxycholic acid (obeticholic acid) is a potent activator of the farnesoid X nuclear receptor that reduces liver fat and fibrosis in animal models of fatty liver disease. We assessed the efficacy of obeticholic acid in adult patients with non-alcoholic steatohepatitis. METHODS We did a multicentre, double-blind, placebo-controlled, parallel group, randomised clinical trial at medical centres in the USA in patients with non-cirrhotic, non-alcoholic steatohepatitis to assess treatment with obeticholic acid given orally (25 mg daily) or placebo for 72 weeks. Patients were randomly assigned 1:1 using a computer-generated, centrally administered procedure, stratified by clinical centre and diabetes status. The primary outcome measure was improvement in centrally scored liver histology defined as a decrease in non-alcoholic fatty liver disease activity score by at least 2 points without worsening of fibrosis from baseline to the end of treatment. A planned interim analysis of change in alanine aminotransferase at 24 weeks undertaken before end-of-treatment (72 weeks) biopsies supported the decision to continue the trial (relative change in alanine aminotransferase -24%, 95% CI -45 to -3). A planned interim analysis of the primary outcome showed improved efficacy of obeticholic acid (p=0·0024) and supported a decision not to do end-of-treatment biopsies and end treatment early in 64 patients, but to continue the trial to obtain the 24-week post-treatment measures. Analyses were done by intention-to-treat. This trial was registered with ClinicalTrials.gov, number NCT01265498. FINDINGS Between March 16, 2011, and Dec 3, 2012, 141 patients were randomly assigned to receive obeticholic acid and 142 to placebo. 50 (45%) of 110 patients in the obeticholic acid group who were meant to have biopsies at baseline and 72 weeks had improved liver histology compared with 23 (21%) of 109 such patients in the placebo group (relative risk 1·9, 95% CI 1·3 to 2·8; p=0·0002). 33 (23%) of 141 patients in the obeticholic acid developed pruritus compared with nine (6%) of 142 in the placebo group. INTERPRETATION Obeticholic acid improved the histological features of non-alcoholic steatohepatitis, but its long-term benefits and safety need further clarification. FUNDING National Institute of Diabetes and Digestive and Kidney Diseases, Intercept Pharmaceuticals.


JAMA | 2011

Effect of Vitamin E or Metformin for Treatment of Nonalcoholic Fatty Liver Disease in Children and Adolescents: The TONIC Randomized Controlled Trial

Joel E. Lavine; Jeffrey B. Schwimmer; Mark L. Van Natta; Jean P. Molleston; Karen F. Murray; Philip J. Rosenthal; Stephanie H. Abrams; Ann O. Scheimann; Arun J. Sanyal; Naga Chalasani; James Tonascia; Aynur Unalp; Jeanne M. Clark; Elizabeth M. Brunt; David E. Kleiner; Jay H. Hoofnagle; Patricia R. Robuck

CONTEXT Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in US children and adolescents and can present with advanced fibrosis or nonalcoholic steatohepatitis (NASH). No treatment has been established. OBJECTIVE To determine whether children with NAFLD would improve from therapeutic intervention with vitamin E or metformin. DESIGN, SETTING, AND PATIENTS Randomized, double-blind, double-dummy, placebo-controlled clinical trial conducted at 10 university clinical research centers in 173 patients (aged 8-17 years) with biopsy-confirmed NAFLD conducted between September 2005 and March 2010. Interventions Daily dosing of 800 IU of vitamin E (58 patients), 1000 mg of metformin (57 patients), or placebo (58 patients) for 96 weeks. MAIN OUTCOME MEASURES The primary outcome was sustained reduction in alanine aminotransferase (ALT) defined as 50% or less of the baseline level or 40 U/L or less at visits every 12 weeks from 48 to 96 weeks of treatment. Improvements in histological features of NAFLD and resolution of NASH were secondary outcome measures. RESULTS Sustained reduction in ALT level was similar to placebo (10/58; 17%; 95% CI, 9% to 29%) in both the vitamin E (15/58; 26%; 95% CI, 15% to 39%; P = .26) and metformin treatment groups (9/57; 16%; 95% CI, 7% to 28%; P = .83). The mean change in ALT level from baseline to 96 weeks was -35.2 U/L (95% CI, -56.9 to -13.5) with placebo vs -48.3 U/L (95% CI, -66.8 to -29.8) with vitamin E (P = .07) and -41.7 U/L (95% CI, -62.9 to -20.5) with metformin (P = .40). The mean change at 96 weeks in hepatocellular ballooning scores was 0.1 with placebo (95% CI, -0.2 to 0.3) vs -0.5 with vitamin E (95% CI, -0.8 to -0.3; P = .006) and -0.3 with metformin (95% CI, -0.6 to -0.0; P = .04); and in NAFLD activity score, -0.7 with placebo (95% CI, -1.3 to -0.2) vs -1.8 with vitamin E (95% CI, -2.4 to -1.2; P = .02) and -1.1 with metformin (95% CI, -1.7 to -0.5; P = .25). Among children with NASH, the proportion who resolved at 96 weeks was 28% with placebo (95% CI, 15% to 45%; 11/39) vs 58% with vitamin E (95% CI, 42% to 73%; 25/43; P = .006) and 41% with metformin (95% CI, 26% to 58%; 16/39; P = .23). Compared with placebo, neither therapy demonstrated significant improvements in other histological features. CONCLUSION Neither vitamin E nor metformin was superior to placebo in attaining the primary outcome of sustained reduction in ALT level in patients with pediatric NAFLD. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00063635.


Hepatology | 2010

Clinical, laboratory and histological associations in adults with nonalcoholic fatty liver disease

Brent A. Neuschwander-Tetri; Jeanne M. Clark; Nathan M. Bass; Mark L. Van Natta; Aynur Unalp-Arida; James Tonascia; Claudia O. Zein; Elizabeth M. Brunt; David E. Kleiner; Arthur J. McCullough; Arun J. Sanyal; Anna Mae Diehl; Joel E. Lavine; Naga Chalasani; Kris V. Kowdley

The Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN) was formed to conduct multicenter studies on the etiology, contributing factors, natural history, and treatment of nonalcoholic steatohepatitis (NASH). The aim of this study was to determine the associations of readily available demographic, clinical, and laboratory variables with the diagnosis of NASH and its key histological features, and determine the ability of these variables to predict the severity of nonalcoholic fatty liver disease (NAFLD). A total of 1266 adults were enrolled in NASH CRN studies between October 2004 and February 2008, of whom 1101 had available liver histology. The median age was 50 years; 82% were white and 12% Hispanic. The median body mass index was 33 kg/m2; 49% had hypertension and 31% had type 2 diabetes. On liver biopsy, 57% were judged to have definite NASH and 31% bridging fibrosis or cirrhosis. Using data from the 698 patients with liver biopsies within 6 months of clinical data, patients with definite NASH were more likely to be female and have diabetes, higher levels of aspartate and alanine aminotransferases, alkaline phosphatase, gamma glutamyl transpeptidase, and homeostasis model assessment of insulin resistance (HOMA‐IR). Progressive models for predicting histological diagnoses performed modestly for predicting steatohepatitis or ballooning (area under receiver operating characteristic curves [AUROC] ranged from 0.70‐0.79), and better for advanced fibrosis (AUROC 0.73‐0.85). Conclusion: Readily available clinical and laboratory variables can predict advanced fibrosis in adults with NAFLD, but additional information is needed to reliably predict the presence and severity of NASH. Prospective studies of this well‐characterized population and associated tissue bank samples offer a unique opportunity to better understand the cause and natural history of NAFLD and develop more precise means for noninvasive diagnosis. (HEPATOLOGY 2010)


The New England Journal of Medicine | 2012

Effect of Inhaled Glucocorticoids in Childhood on Adult Height

H. William Kelly; Alice L. Sternberg; Rachel Lescher; Anne L. Fuhlbrigge; Paul V. Williams; Robert S. Zeiger; Hengameh H. Raissy; Mark L. Van Natta; James Tonascia; Robert C. Strunk

BACKGROUND The use of inhaled glucocorticoids for persistent asthma causes a temporary reduction in growth velocity in prepubertal children. The resulting decrease in attained height 1 to 4 years after the initiation of inhaled glucocorticoids is thought not to decrease attained adult height. METHODS We measured adult height in 943 of 1041 participants (90.6%) in the Childhood Asthma Management Program; adult height was determined at a mean (±SD) age of 24.9±2.7 years. Starting at the age of 5 to 13 years, the participants had been randomly assigned to receive 400 μg of budesonide, 16 mg of nedocromil, or placebo daily for 4 to 6 years. We calculated differences in adult height for each active treatment group, as compared with placebo, using multiple linear regression with adjustment for demographic characteristics, asthma features, and height at trial entry. RESULTS Mean adult height was 1.2 cm lower (95% confidence interval [CI], -1.9 to -0.5) in the budesonide group than in the placebo group (P=0.001) and was 0.2 cm lower (95% CI, -0.9 to 0.5) in the nedocromil group than in the placebo group (P=0.61). A larger daily dose of inhaled glucocorticoid in the first 2 years was associated with a lower adult height (-0.1 cm for each microgram per kilogram of body weight) (P=0.007). The reduction in adult height in the budesonide group as compared with the placebo group was similar to that seen after 2 years of treatment (-1.3 cm; 95% CI, -1.7 to -0.9). During the first 2 years, decreased growth velocity in the budesonide group occurred primarily in prepubertal participants. CONCLUSIONS The initial decrease in attained height associated with the use of inhaled glucocorticoids in prepubertal children persisted as a reduction in adult height, although the decrease was not progressive or cumulative. (Funded by the National Heart, Lung, and Blood Institute and the National Center for Research Resources; CAMP ClinicalTrials.gov number, NCT00000575.).


PLOS Pathogens | 2014

HIV-Infected Individuals with Low CD4/CD8 Ratio despite Effective Antiretroviral Therapy Exhibit Altered T Cell Subsets, Heightened CD8+ T Cell Activation, and Increased Risk of Non-AIDS Morbidity and Mortality

Sergio Serrano-Villar; Talía Sainz; Sulggi A. Lee; Peter W. Hunt; Elizabeth Sinclair; Barbara L. Shacklett; April L. Ferre; Timothy L. Hayes; Ma Somsouk; Priscilla Y. Hsue; Mark L. Van Natta; Curtis L. Meinert; Michael M. Lederman; Hiroyu Hatano; Vivek Jain; Yong Huang; Frederick Hecht; Jeffrey N. Martin; Joseph M. McCune; Santiago Moreno; Steven G. Deeks

A low CD4/CD8 ratio in elderly HIV-uninfected adults is associated with increased morbidity and mortality. A subset of HIV-infected adults receiving effective antiretroviral therapy (ART) fails to normalize this ratio, even after they achieve normal CD4+ T cell counts. The immunologic and clinical characteristics of this clinical phenotype remain undefined. Using data from four distinct clinical cohorts and three clinical trials, we show that a low CD4/CD8 ratio in HIV-infected adults during otherwise effective ART (after CD4 count recovery above 500 cells/mm3) is associated with a number of immunological abnormalities, including a skewed T cell phenotype from naïve toward terminally differentiated CD8+ T cells, higher levels of CD8+ T cell activation (HLADR+CD38+) and senescence (CD28− and CD57+CD28−), and higher kynurenine/tryptophan ratio. Changes in the peripheral CD4/CD8 ratio are also reflective of changes in gut mucosa, but not in lymph nodes. In a longitudinal study, individuals who initiated ART within six months of infection had greater CD4/CD8 ratio increase compared to later initiators (>2 years). After controlling for age, gender, ART duration, nadir and CD4 count, the CD4/CD8 ratio predicted increased risk of morbidity and mortality. Hence, a persistently low CD4/CD8 ratio during otherwise effective ART is associated with increased innate and adaptive immune activation, an immunosenescent phenotype, and higher risk of morbidity/mortality. This ratio may prove useful in monitoring response to ART and could identify a unique subset of individuals needed of novel therapeutic interventions.


The Journal of Infectious Diseases | 2014

Gut Epithelial Barrier Dysfunction and Innate Immune Activation Predict Mortality in Treated HIV Infection

Peter W. Hunt; Elizabeth Sinclair; Benigno Rodriguez; Carey L. Shive; Brian Clagett; Nicholas T. Funderburg; Janet Robinson; Yong Huang; Lorrie Epling; Jeffrey N. Martin; Steven G. Deeks; Curtis L. Meinert; Mark L. Van Natta; Douglas A. Jabs; Michael M. Lederman

BACKGROUND While inflammation predicts mortality in treated human immunodeficiency virus (HIV) infection, the prognostic significance of gut barrier dysfunction and phenotypic T-cell markers remains unclear. METHODS We assessed immunologic predictors of mortality in a case-control study within the Longitudinal Study of the Ocular Complications of AIDS (LSOCA), using conditional logistic regression. Sixty-four case patients who died within 12 months of treatment-mediated viral suppression were each matched to 2 control individuals (total number of controls, 128) by duration of antiretroviral therapy-mediated viral suppression, nadir CD4(+) T-cell count, age, sex, and prior cytomegalovirus (CMV) retinitis. A similar secondary analysis was conducted in the SCOPE cohort, which had participants with less advanced immunodeficiency. RESULTS Plasma gut epithelial barrier integrity markers (intestinal fatty acid binding protein and zonulin-1 levels), soluble CD14 level, kynurenine/tryptophan ratio, soluble tumor necrosis factor receptor 1 level, high-sensitivity C-reactive protein level, and D-dimer level all strongly predicted mortality, even after adjustment for proximal CD4(+) T-cell count (all P ≤ .001). A higher percentage of CD38(+)HLA-DR(+) cells in the CD8(+) T-cell population was a predictor of mortality before (P = .031) but not after (P = .10) adjustment for proximal CD4(+) T-cell count. Frequencies of senescent (defined as CD28(-)CD57(+) cells), exhausted (defined as PD1(+) cells), naive, and CMV-specific T cells did not predict mortality. CONCLUSIONS Gut epithelial barrier dysfunction, innate immune activation, inflammation, and coagulation-but not T-cell activation, senescence, and exhaustion-independently predict mortality in individuals with treated HIV infection with a history of AIDS and are viable targets for interventions.


Gastroenterology | 2008

Clinical Correlates of Histopathology in Pediatric Nonalcoholic Steatohepatitis

Heather Patton; Joel E. Lavine; Mark L. Van Natta; Jeffrey B. Schwimmer; David E. Kleiner; Jean P. Molleston

BACKGROUND & AIMS Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver disease in American children. Noninvasive means to discriminate between NAFLD and nonalcoholic steatohepatitis (NASH) might diminish the requirement for liver biopsy or predict those at increased risk for progression. METHODS Data obtained prospectively from children (age, 6-17 y) enrolled in the NASH Clinical Research Network were analyzed to identify clinical-pathologic correlates of pediatric NAFLD. All participants underwent liver biopsy within 6 months of clinical data that were reviewed by a central pathology committee. RESULTS A total of 176 children (mean age, 12.4 y; 77% male) were eligible for inclusion. By using ordinal logistic regression analysis, increasing aspartate aminotransferase (AST) level (odds ratio [OR], 1.017 per U/L; 95% confidence interval [CI], 1.004-1.031) and gamma-glutamyltransferase level (OR, 1.016 per U/L; 95% CI, 1.000-1.033) were associated independently with increasing severity of NASH. Increasing AST level (OR, 1.015 per U/L; 95% CI, 1.006-1.024), increasing white blood cell count (OR, 1.22 per 1000/mm(3); 95% CI, 1.07-1.38), and decreasing hematocrit (OR, 0.87 per %; 95% CI, 0.79-0.96) were associated independently with increasing severity of fibrosis. Area under the receiver operator characteristic curve for a model with AST and alanine aminotransferase was 0.75 (95% CI, 0.66-0.84) and 0.74 (95% CI, 0.63-0.85) for distinguishing steatosis from more advanced forms of NASH and bridging fibrosis from lesser degrees of fibrosis, respectively. CONCLUSIONS Certain components of routine laboratory tests are predictive of NAFLD pattern and fibrosis severity, but do not have adequate discriminate power to replace liver biopsy in evaluating pediatric NAFLD.


Pediatrics | 2008

Effect of Long-term Corticosteroid Use on Bone Mineral Density in Children: A Prospective Longitudinal Assessment in the Childhood Asthma Management Program (CAMP) Study

H. William Kelly; Mark L. Van Natta; Ronina A. Covar; James Tonascia; Robert C. Strunk

OBJECTIVE. Systemic corticosteroids are known to induce osteoporosis and increase the risk for fractures in adults and children. Inhaled corticosteroids have been shown to increase the risk for osteoporosis and fractures in adults at risk; however, long-term prospective studies of children to assess risks of multiple short courses of oral corticosteroids and chronic inhaled corticosteroids have not been performed. Thus, we assessed the effects of multiple short courses of oral corticosteroids and long-term inhaled corticosteroids on bone mineral accretion over a period of years. METHODS. This was a cohort follow-up study for a median of 7 years of children who had mild-to-moderate asthma and initially were randomly assigned into the Childhood Asthma Management Program trial. Serial dual-energy radiograph absorptiometry scans of the lumbar spine for bone mineral density were performed for all patients. Annual bone mineral accretion was calculated for 531 boys and 346 girls who had asthma and were aged 5 to 12 years at baseline (84% of the initial cohort). RESULTS. Oral corticosteroid bursts produced a dosage-dependent reduction in bone mineral accretion (0.052, 0.049, and 0.046 g/cm2 per year) and an increase in risk for osteopenia (10%, 14%, and 21%) for 0, 1 to 4, and ≥5 courses, respectively, in boys but not girls. Cumulative inhaled corticosteroid use was associated with a small decrease in bone mineral accretion in boys but not girls but no increased risk for osteopenia. CONCLUSIONS. Multiple oral corticosteroid bursts over a period of years can produce a dosage-dependent reduction in bone mineral accretion and increased risk for osteopenia in children with asthma. Inhaled corticosteroid use has the potential for reducing bone mineral accretion in male children progressing through puberty, but this risk is likely to be outweighed by the ability to reduce the amount of oral corticosteroids used in these children.

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Douglas A. Jabs

Icahn School of Medicine at Mount Sinai

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James Tonascia

Johns Hopkins University

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David E. Kleiner

National Institutes of Health

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Frank A. Hamilton

National Institutes of Health

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Richard W. McCallum

Texas Tech University Health Sciences Center

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William J. Snape

California Pacific Medical Center

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