Veterans Health Administration

About: Veterans Health Administration is a government organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Population & Veterans Affairs. The organization has 63820 authors who have published 98417 publications receiving 4835425 citations. The organization is also known as: VHA.

Gamma frequency-range abnormalities to auditory stimulation in schizophrenia

Abstract: Background Basic science studies at the neuronal systems level have indicated that gamma-range (30-50 Hz) neural synchronization may be a key mechanism of information processing in neural networks, reflecting integration of various features of an object. Furthermore, gamma-range synchronization is thought to depend on the glutamatergically mediated interplay between excitatory projection neurons and inhibitory neurons utilizing γ-aminobutyric acid (GABA), which postmortem studies suggest may be abnormal in schizophrenia. We therefore tested whether auditory neural networks in patients with schizophrenia could support gamma-range synchronization. Methods Synchronization of the electroencephalogram (EEG) to different rates (20-40 Hz) of auditory stimulation was recorded from 15 patients with schizophrenia and 15 sex-, age-, and handedness-matched control subjects. The EEG power at each stimulation frequency was compared between groups. The time course of the phase relationship between each stimulus and EEG peak was also evaluated for gamma-range (40 Hz) stimulation. Results Schizophrenic patients showed reduced EEG power at 40 Hz, but not at lower frequencies of stimulation. In addition, schizophrenic patients showed delayed onset of phase synchronization and delayed desynchronization to the click train. Conclusions These data provide new information on selective deficits in early-stage sensory processing in schizophrenia, a failure to support the entrainment of intrinsic gamma-frequency oscillators. The reduced EEG power at 40 Hz in schizophrenic patients may reflect a dysfunction of the recurrent inhibitory drive on auditory neural networks.

Prevalence of nonpolypoid (flat and depressed) colorectal neoplasms in asymptomatic and symptomatic adults.

Abstract: Context Colorectal cancer is the second leading cause of cancer death in the United States. Prevention has focused on the detection and removal of polypoid neoplasms. Data are limited on the significance of nonpolypoid colorectal neoplasms (NP-CRNs). Objectives To determine the prevalence of NP-CRNs in a veterans hospital population and to characterize their association with colorectal cancer. Design, Setting, and Patients Cross-sectional study at a veterans hospital in California with 1819 patients undergoing elective colonoscopy from July 2003 to June 2004. Main Outcome Measures Endoscopic appearance, location, size, histology, and depth of invasion of neoplasms. Results The overall prevalence of NP-CRNs was 9.35% (95% confidence interval [95% CI], 8.05%-10.78%; n = 170). The prevalence of NP-CRNs in the subpopulations for screening, surveillance, and symptoms was 5.84% (95% CI, 4.13%-8.00%; n = 36), 15.44% (95% CI, 12.76%-18.44%; n = 101), and 6.01% (95% CI, 4.17%-8.34%; n = 33), respectively. The overall prevalence of NP-CRNs with in situ or submucosal invasive carcinoma was 0.82% (95% CI, 0.46%-1.36%; n = 15); in the screening population, the prevalence was 0.32% (95% CI, 0.04%-1.17%; n = 2). Overall, NP-CRNs were more likely to contain carcinoma (odds ratio, 9.78; 95% CI, 3.93-24.4) than polypoid lesions, irrespective of the size. The positive size-adjusted association of NP-CRNs with in situ or submucosal invasive carcinoma was also observed in subpopulations for screening (odds ratio, 2.01; 95% CI, 0.27-15.3) and surveillance (odds ratio, 63.7; 95% CI, 9.41-431). The depressed type had the highest risk (33%). Nonpolypoid colorectal neoplasms containing carcinoma were smaller in diameter as compared with the polypoid ones (mean [SD] diameter, 15.9 [10.2] mm vs 19.2 [9.6] mm, respectively). The procedure times did not change appreciably as compared with historical controls. Conclusion In this group of veteran patients, NP-CRNs were relatively common lesions diagnosed during routine colonoscopy and had a greater association with carcinoma compared with polypoid neoplasms, irrespective of size.

Genome-wide association study identifies variants in the ABO locus associated with susceptibility to pancreatic cancer

Abstract: We conducted a two-stage genome-wide association study of pancreatic cancer, a cancer with one of the lowest survival rates worldwide. We genotyped 558,542 SNPs in 1,896 individuals with pancreatic cancer and 1,939 controls drawn from 12 prospective cohorts plus one hospital-based case-control study. We conducted a combined analysis of these groups plus an additional 2,457 affected individuals and 2,654 controls from eight case-control studies, adjusting for study, sex, ancestry and five principal components. We identified an association between a locus on 9q34 and pancreatic cancer marked by the SNP rs505922 (combined P = 5.37 x 10(-8); multiplicative per-allele odds ratio 1.20; 95% confidence interval 1.12-1.28). This SNP maps to the first intron of the ABO blood group gene. Our results are consistent with earlier epidemiologic evidence suggesting that people with blood group O may have a lower risk of pancreatic cancer than those with groups A or B.

Visceral adiposity and risk of type 2 diabetes: a prospective study among Japanese Americans.

Abstract: OBJECTIVE: We conducted a prospective study among Japanese Americans of diabetes incidence in relation to visceral and regional adiposity, fasting insulin and C-peptide, and a measure of insulin secretion, because little prospective data exist on these associations. RESEARCH DESIGN AND METHODS: Baseline variables included plasma glucose, C-peptide, and insulin measured after an overnight fast and 30 and 120 min after a 75-g oral glucose tolerance test; abdominal, thoracic, and thigh fat areas by computed tomography (CT); BMI (kg/m2); and insulin secretion (incremental insulin response [IIR]). RESULTS: Study subjects included 290 second-generation (nisei) and 230 third-generation (sansei) Japanese Americans without diabetes, of whom 65 and 13, respectively, developed diabetes. Among nisei, significant predictors of diabetes risk for a 1 SD increase in continuous variables included intra-abdominal fat area (IAFA) (odds ratio, 95% CI) (1.6, 1.1-2.3), fasting plasma C-peptide (1.4, 1.1-1.8), and the IIR (0.5, 0.3-0.9) after adjusting for age, sex, impaired glucose tolerance, family diabetes history, and CT-measured fat areas other than intra-abdominal. Intra-abdominal fat area remained a significant predictor of diabetes incidence even after adjustment for BMI, total body fat area, and subcutaneous fat area, although no measure of regional or total adiposity was related to development of diabetes. Among sansei, all adiposity measures were related to diabetes incidence, but, in adjusted models, only IAFA remained significantly associated with higher risk (2.7, 1.4-5.4, BMI-adjusted). CONCLUSIONS: Greater visceral adiposity precedes the development of type 2 diabetes in Japanese Americans and demonstrates an effect independent of fasting insulin, insulin secretion, glycemia, total and regional adiposity, and family history of diabetes.