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Dive into the research topics where Ned Snyder is active.

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Featured researches published by Ned Snyder.


Gastroenterology | 2009

Visualizing Hepatitis C Virus Infections in Human Liver by Two-Photon Microscopy

Yuqiong Liang; Tuya Shilagard; Shu Yuan Xiao; Ned Snyder; Daryl Lau; Luca Cicalese; Heidi L. Weiss; Gracie Vargas; Stanley M. Lemon

BACKGROUND & AIMS Although hepatitis C virus (HCV) is a common cause of cirrhosis and liver cancer, efforts to understand the pathogenesis of HCV infection have been limited by the low abundance of viral proteins expressed within the liver, which hinders the detection of infected cells in situ. This study evaluated the ability of advanced optical imaging techniques to determine the extent and distribution of HCV-infected cells within the liver. METHODS We combined 2-photon microscopy with virus-specific, fluorescent, semiconductor quantum dot probes to determine the proportion of hepatocytes that were infected with virus in frozen sections of liver tissue obtained from patients with chronic HCV infection. RESULTS Viral core and nonstructural protein 3 antigens were detected readily in liver tissues from patients with chronic infection without confounding tissue autofluorescence. Specificity was confirmed by blocking with specific antibodies and by tissue colocalization of distinct viral antigens. Between 7% and 20% of hepatocytes were infected in patients with plasma viral RNA loads of 10(5) IU/mL or greater. Infected cells were in clusters, which suggested spread of the virus from cell to cell. Double-stranded RNA, a product of viral replication, was abundant within cells at the center of such clusters, but often scarce in cells at the periphery, consistent with more recent infection of cells at the periphery. CONCLUSIONS Two-photon microscopy provides unprecedented sensitivity for the detection of HCV proteins and double-stranded RNA. Studies using this technology indicate that HCV infection is a dynamic process that involves a limited number of hepatocytes. HCV spread between cells is likely to be constrained by host responses.


Journal of Clinical Gastroenterology | 2006

APRI : An easy and validated predictor of hepatic fibrosis in chronic hepatitis C

Ned Snyder; Leka Gajula; Shu Yuan Xiao; James J. Grady; Bruce A. Luxon; Daryl Lau; Roger D. Soloway; John R. Petersen

Goals To evaluate the aspartate aminotransferase/platelet ratio index (APRI) as a predictor of the presence or absence of significant fibrosis on liver biopsy of patients with chronic hepatitis C (HCV). Background The decision to treat HCV is often made on the basis of the presence or absence of significant fibrosis on the liver biopsy. Because liver biopsy is expensive and invasive a noninvasive marker to evaluate hepatic fibrosis would be useful. The APRI is an easy to calculate index that is one of several markers that have been proposed. Study We retrospectively reviewed the charts of 339 patients with chronic HCV who had liver biopsies from January 2000 to March 2003. We subsequently evaluated 151 patients receiving pretreatment evaluation liver biopsies who had serum aspartate aminotransferase, platelets, routine liver function tests, and demographic data obtained. All liver biopsies were staged by the Batts Ludwig criteria. Results The area under the curve of the receiver operator characteristics of the calculated APRI compared with the liver biopsy demonstrated that the fibrosis score was 0.889 in the prospective group and 0.790 in the retrospective group. To achieve predictive values of approximately 90%, useful cutoffs were found at 0.40 and 1.5 in the retrospective study, and 0.42 and 1.2 in the prospective study leaving intermediate zones of 58.9% and 41.1%, respectively. In the prospective group, 34 of 36 patients with a value of <0.42 were accurately predicted as having mild fibrosis, whereas 50 of 54 patients with a value >1.2 were accurately predicted to have significant fibrosis. Conclusions The APRI is a good estimator of hepatic fibrosis and was more accurate in a prospective group than a retrospective one. It potentially could be used to decrease the number of liver biopsies.


Plastic and Reconstructive Surgery | 2000

Bipedicle paraspinous muscle flaps for spinal wound closure: an anatomic and clinical study.

Bradon J. Wilhelmi; Ned Snyder; Tiffany Colquhoun; Alexander Hadjipavlou; Linda G. Phillips

&NA; The purpose of this study was to evaluate the vascular anatomy of the paraspinous muscles and review their clinical use as bipedicled flaps in spinal wound closure. Anatomically, through cadaver dissections, lead oxide injections, and radiographic imaging, the blood supply to the paraspinous muscles was determined. Clinically, 29 consecutive patients treated with spinal wounds and exposed bone or hardware were reviewed retrospectively. Of these patients, 19 underwent closure in delayed primary fashion, whereas 10 were referred to plastic surgery for reconstruction because of the complex nature of their wounds. The cadaver study demonstrated the paraspinous muscles to possess a segmental arterial supply through medial and lateral perforators. Division of the medial perforators allowed for medial advancement of the muscles. Lead oxide injection of the lateral perforators demonstrated adequate medial muscle perfusion with ligation of the medial perforators. Ten of the 29 patients (six women, four men, 32 to 62 years of age) were reconstructed with paraspinous (eight), latissimus (one), and trapezius (one) muscle flaps. A higher complication rate was found in wounds closed in delayed primary fashion (13 of 19 patients, 68 percent) than those reconstructed with muscle flaps (2 of 10 patients, 20 percent) (p = 0.021). Follow‐up of the muscle flap reconstructed patients averaged 12 months (range, 3 to 27 months). Cadaver muscle injections predicted and clinical cases confirmed that the paraspinous muscles can be raised on lateral perforators and advanced medially to close lumbar spine wounds reliably with fewer complications. (Plast. Reconstr. Surg. 106: 1305, 2000.)


Digestive Diseases and Sciences | 1978

Depressed delayed cutaneous hypersensitivity in alcoholic hepatitis

Ned Snyder; Joel Bessoff; John M. Dwyer; Harold O. Conn

Delayed cutaneous hypersensitivity was studied in 10 patients with severe alcoholic hepatitis, 9 patients with either inactive alcoholic cirrhosis or alcoholic fatty liver, and 10 age-matched controls. The mean response of the alcoholic hepatitis group was significantly less compared to controls for SK-SD (P<0.001), mumps (P<0.001), trichophyton (P<0.025), andCandida albicans (P<0.025). Upon clinical recovery, the response of the 6 surviving patients with alcoholic hepatitis was similar to controls for 4 of the 5 antigens tested, and the improvements in response to SK-SD andCandida albicans were significant (P<0.02 and P<0.05). The mean percentage and absolute numbers of thymus-derived lymphocytes were significantly less in the alcoholic hepatitis group compared with controls. Both the alcoholic hepatitis patients and patients with less advanced alcoholic liver disease had a diminished response to concanavalin A and phytohemagglutinin. This study demonstrates a reversible depression of delayed cutaneous hypersensitivity in alcoholic hepatitis. Several mechanisms may help account for this finding. We recommend that skin tests in patients with alcoholic hepatitis be interpreted with this phenomenon in mind.


Plastic and Reconstructive Surgery | 2005

The Incidence of Tuberous Breast Deformity in Asymmetric and Symmetric Mammaplasty Patients

Danielle M. Deluca-Pytell; Rocco C. Piazza; Julie Holding; Ned Snyder; Lisa M. Hunsicker; Linda G. Phillips

BACKGROUND Breast asymmetry is commonly accompanied by tuberous deformity. To date, no study has reported the incidence of this breast deformity in the presence of asymmetry. A retrospective analysis of standard preoperative photographs was performed on 375 consecutive female patients presenting for mammaplasty over a 10-year span. METHODS Women were examined for symmetry, asymmetry, and the presence of tuberous deformity. Patients were graded by the Grolleau Classification System. Patients having congenital anomalies, tumors, infection, radiation, chest wall deformities, previous breast surgery history, and incomplete chart data were excluded. RESULTS Of the 375 patients studied, 81.1 percent (n = 304) presented with asymmetry. Of these asymmetric women, 88.8 percent (n = 270) were found to have tuberous deformity. Of the 71 patients who were symmetric, 7 percent (n = 5) were tuberous. Concurrent nipple-areola complex involvement in the tuberous asymmetric patient population was present in 50 percent of the women (n = 116). Of the tuberous deformities with nipple-areola complex, 87.9 percent (n = 116) were Grolleau type III. Nipple-areola complex involvement was not found in any of the symmetric patients. Of the 275 women with tuberous deformity, 531 breasts were tuberous and 60.3 percent (n = 320) were Grolleaus type III. In total, 57.1 percent of all reduction mammaplasties (n = 92) and 83.2 percent of all augmentation mammaplasties (n = 178) had asymmetry with tuberous deformity. CONCLUSIONS This is the first published study to demonstrate that tuberous deformity is strongly associated with asymmetry in women presenting for mammaplasty. This should be evaluated in preoperative planning to ensure optimal outcome. Patients with this deformity should be educated preoperatively so their expectations of postoperative results are realistic.


Clinica Chimica Acta | 2008

Non-invasive markers of hepatic fibrosis in patients co-infected with HCV and HIV: Comparison of the APRI and FIB-4 index

Tony Trang; John R. Petersen; Ned Snyder

INTRODUCTION The APRI and FIB-4 index are markers that have been proposed for the evaluation of hepatic fibrosis in patients co-infected with HIV and HCV. METHODS We retrospectively compared these 2 indices in 81 co-infected patients staged by liver biopsy. RESULTS The FIB-4 index was superior to the APRI for the differentiation of mild from significant fibrosis in both predictive values and area under the receiver operator curve (AUROC). The tests were comparable for the differentiation of mild/moderate from advanced fibrosis. CONCLUSION These tests could be used to evaluate co-infected patients for treatment, and exclude those that do not need periodic screening for hepatocellular carcinoma.


Molecular & Cellular Proteomics | 2013

Biomarker Discovery for Early Detection of Hepatocellular Carcinoma in Hepatitis C–infected Patients

Mehnaz G. Mustafa; John R. Petersen; Hyunsu Ju; Luca Cicalese; Ned Snyder; Sigmund J. Haidacher; Larry Denner; Cornelis J. Elferink

Chronic hepatic disease damages the liver, and the resulting wound-healing process leads to liver fibrosis and the subsequent development of cirrhosis. The leading cause of hepatic fibrosis and cirrhosis is infection with hepatitis C virus (HCV), and of the patients with HCV-induced cirrhosis, 2% to 5% develop hepatocellular carcinoma (HCC), with a survival rate of 7%. HCC is one of the leading causes of cancer-related death worldwide, and the poor survival rate is largely due to late-stage diagnosis, which makes successful intervention difficult, if not impossible. The lack of sensitive and specific diagnostic tools and the urgent need for early-stage diagnosis prompted us to discover new candidate biomarkers for HCV and HCC. We used aptamer-based fractionation technology to reduce serum complexity, differentially labeled samples (six HCV and six HCC) with fluorescent dyes, and resolved proteins in pairwise two-dimensional difference gel electrophoresis. DeCyder software was used to identify differentially expressed proteins and spots picked, and MALDI-MS/MS was used to determine that ApoA1 was down-regulated by 22% (p < 0.004) in HCC relative to HCV. Differential expression quantified via two-dimensional difference gel electrophoresis was confirmed by means of 18O/16O stable isotope differential labeling with LC-MS/MS zoom scans. Technically independent confirmation was demonstrated by triple quadrupole LC-MS/MS selected reaction monitoring (SRM) assays with three peptides specific to human ApoA1 (DLATVYVDVLK, WQEEMELYR, and VSFLSALEEYTK) using 18O/16O-labeled samples and further verified with AQUA peptides as internal standards for quantification. In 50 patient samples (24 HCV and 26 HCC), all three SRM assays yielded highly similar differential expression of ApoA1 in HCC and HCV patients. These results validated the SRM assays, which were independently confirmed by Western blotting. Thus, ApoA1 is a candidate member of an SRM biomarker panel for early diagnosis, prognosis, and monitoring of HCC. Future multiplexing of SRM assays for other candidate biomarkers is envisioned to develop a biomarker panel for subsequent verification and validation studies.


Annals of Internal Medicine | 1974

Hypergastrinemia in Familial Multiple Endocrine Adenomatosis

Ned Snyder; Murphy T. Scurry; William S. Hughes

Abstract Fasting serum gastrin levels of 46 members of 5 families with familial multiple endocrine adenomatosis were measured; 14 patients had hypergastrinemia (a serum gastrin level greater than 2...


Public Health Reports | 2009

Hepatocellular carcinoma prevalence and mortality in a male state prison population

Jacques Baillargeon; Ned Snyder; Roger D. Soloway; David P. Paar; Gwen Baillargeon; Anne C. Spaulding; Brad H. Pollock; Christine M. Arcari; Brie A. Williams; Ben G. Raimer

Objectives. The incidence of hepatocellular carcinoma (HCC) in the United States has increased dramatically over the last two decades, largely because of an increase in the number of people with advanced hepatitis C virus (HCV) infection. U.S. prisoners are at high risk for HCC, given their elevated rates of HCV infection, comorbid hepatitis B virus (HBV) infection, and alcoholic liver disease. The purpose of our study was to examine the prevalence and mortality of HCC in the nations largest state prison system. Methods. The study population consisted of 325,477 male Texas Department of Criminal Justice (TDCJ) inmates who were incarcerated between January 1, 2003, and July 31, 2006. Information on medical conditions and demographic characteristics was obtained from an institution-wide medical information system. Results. During the 3.5-year study period, 176 male TDCJ inmates (54 per 100,000) were diagnosed with HCC and 108 (33 per 100,000) died as a result of HCC. Inmates who were Hispanic, older, and infected with HCV, HBV, or human immunodeficiency virus had elevated rates of both HCC prevalence and mortality. After adjusting for all study covariates, HCC prevalence, but not mortality, was modestly elevated among inmates with diabetes. Conclusions. Our study showed that the Texas male prison population had a sevenfold higher prevalence of HCC than the general U.S. male population and a fourfold higher death rate from HCC. These findings likely reflect the high concentration of HCC-related risk factors, particularly HCV, among prisoners.


Digestive Diseases and Sciences | 1977

Antral gastrin concentration in upper-gastrointestinal disease

William S. Hughes; Ned Snyder; Alfred J. Hernandez

Antral gastrin concentration (AGC) was measured in prepyloric mucosa specimens obtained by forceps biopsy during endoscopic examination of 174 clinic and hospital patients. AGC in 32 patients who had normal endoscopic findings, the control group, varied widely from 2 to 38.6 ng gastrin/mg tissue. The mean AGC of the control patients was 14.2±1.4 (mean ±1se) ng gastrin/mg tissue. AGC was similar to control values in 18 patients with duodenal ulcer, 14.7±2.1; 12 patients with a pyloric channel or antral ulcer, 16.4±3.5; and 48 patients with miscellaneous diagnoses, 14.3±1.5 AGC was significantly less than control values in 13 patients with a ulcer in the body or fundus of the stomach, 5.9±1.5, and 4 patients with the Zollinger-Ellison syndrome, 4.9±2.4. AGC was significantly greater than in control values in 16 patients with gastritis, 25.8±4.3; 22 patients with esophagitis, 23.2±3.0; and 9 patients with gastric atrophy and fasting serum hypergastrinemia 44.6±12.3. In a group of 77 of these patients with heterogeneous diagnoses, meal-stimulated 3-hr integrated gastrin output was directly related to AGC (r=0.47,P<0.001). In a group of 106 patients AGC was inversely related to histalogstimulated maximum acid output. The correlation was very weak (r=−0.20) but significant (P<0.05).

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John R. Petersen

University of Texas Medical Branch

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Shu Yuan Xiao

University of Texas Medical Branch

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Gottumukkala S. Raju

University of Texas MD Anderson Cancer Center

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Karen Szauter

University of Texas Medical Branch

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Linda G. Phillips

University of Texas Medical Branch

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Luca Cicalese

University of Texas Medical Branch

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Roger D. Soloway

University of Pennsylvania

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William S. Hughes

University of Texas Medical Branch

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Daryl Lau

Beth Israel Deaconess Medical Center

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Heidi L. Weiss

University of Alabama at Birmingham

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