University of Texas Medical Branch

About: University of Texas Medical Branch is a education organization based out in Galveston, Texas, United States. It is known for research contribution in the topics: Population & Virus. The organization has 22033 authors who have published 38268 publications receiving 1517502 citations. The organization is also known as: The University of Texas Medical Branch at Galveston & UTMB.

Accelerated neurodegeneration through chaperone-mediated oligomerization of tau

Abstract: Aggregation of tau protein in the brain is associated with a class of neurodegenerative diseases known as tauopathies. FK506 binding protein 51 kDa (FKBP51, encoded by FKBP5) forms a mature chaperone complex with Hsp90 that prevents tau degradation. In this study, we have shown that tau levels are reduced throughout the brains of Fkbp5–/– mice. Recombinant FKBP51 and Hsp90 synergized to block tau clearance through the proteasome, resulting in tau oligomerization. Overexpression of FKBP51 in a tau transgenic mouse model revealed that FKBP51 preserved the species of tau that have been linked to Alzheimer’s disease (AD) pathogenesis, blocked amyloid formation, and decreased tangle load in the brain. Alterations in tau turnover and aggregate structure corresponded with enhanced neurotoxicity in mice. In human brains, FKBP51 levels increased relative to age and AD, corresponding with demethylation of the regulatory regions in the FKBP5 gene. We also found that higher FKBP51 levels were associated with AD progression. Our data support a model in which age-associated increases in FKBP51 levels and its interaction with Hsp90 promote neurotoxic tau accumulation. Strategies aimed at attenuating FKBP51 levels or its interaction with Hsp90 have the potential to be therapeutically relevant for AD and other tauopathies.

Rapid Antimanic Effect of Risperidone Monotherapy: A 3-Week Multicenter, Double-Blind, Placebo-Controlled Trial

Abstract: OBJECTIVE: This study evaluated the efficacy and safety of risperidone monotherapy in the treatment of acute bipolar mania. METHOD: Patients with DSM-IV bipolar I disorder experiencing an acute manic episode (baseline Young Mania Rating Scale score ≥20) were randomly assigned to 3 weeks of treatment with risperidone (flexible dose: 1–6 mg/day) or placebo. The primary efficacy measure was the mean baseline-to-endpoint change in total score on the Young Mania Rating Scale. Secondary efficacy measures included the Clinical Global Impression (CGI) severity rating and scores on the Montgomery-Asberg Depression Rating Scale, Positive and Negative Syndrome Scale, and Global Assessment Scale (GAS). Safety assessments consisted of monitoring adverse events, vital signs, electrocardiogram and laboratory results, and scores on the Extrapyramidal Symptom Rating Scale. RESULTS: Subjects (N=259) received treatment with either risperidone (N=134) or placebo (N=125). The mean modal dose of risperidone was 4.1 mg/day. Imp...

Asymptomatic HIV-associated neurocognitive impairment increases risk for symptomatic decline.

Abstract: Objective: While HIV-associated neurocognitive disorders (HAND) remain prevalent despite combination antiretroviral therapy (CART), the clinical relevance of asymptomatic neurocognitive impairment (ANI), the most common HAND diagnosis, remains unclear. We investigated whether HIV-infected persons with ANI were more likely than those who were neurocognitively normal (NCN) to experience a decline in everyday functioning (symptomatic decline). Methods: A total of 347 human participants from the CNS HIV Anti-Retroviral Therapy Effects Research (CHARTER) cohort were NCN (n = 226) or had ANI (n = 121) at baseline. Neurocognitive assessments occurred approximately every 6 months, with median (interquartile range) follow-up of 45.2 (28.7–63.7) months. Symptomatic decline was based on self-report (SR) or objective, performance-based (PB) problems in everyday functioning. Proportional hazards modeling was used to generate risk ratios for progression to symptomatic HAND after adjusting for baseline and time-dependent covariates, including CD4+ T-lymphocyte count (CD4), virologic suppression, CART, and mood. Results: The ANI group had a shorter time to symptomatic HAND than the NCN after adjusting for baseline predictors: adjusted risk ratios for symptomatic HAND were 2.0 (confidence interval [CI] 1.1–3.6; p = 0.02) for SR, 5.8 (CI 3.2–10.7; p p Conclusions: This longitudinal study demonstrates that ANI conveys a 2-fold to 6-fold increase in risk for earlier development of symptomatic HAND, supporting the prognostic value of the ANI diagnosis in clinical settings. Identifying those at highest risk for symptomatic decline may offer an opportunity to modify treatment to delay progression.

Regulation of Muscle Protein by Amino Acids

Abstract: Amino acid availability is a potent regulator of muscle protein synthesis (MPS) We have performed a series of studies using stable isotope methodology and the arteriovenous balance approach to quantify many aspects of the response of MPS, breakdown, and the balance between synthesis and breakdown to changes in the availability of amino acids A constant intake of amino acids stimulates MPS in a dose-dependent manner until concentrations are approximately doubled, after which further increases in concentration are ineffective MPS rises more rapidly after bolus ingestion to a peak rate of MPS higher than during constant intake, but the response is transient A reduction in amino acid availability below basal levels inhibits MPS Ingestion of nonessential amino acids is not needed to stimulate MPS When carbohydrate alone is ingested there is minimal effect on MPS, but there is an interactive effect with amino acid ingestion, meaning the response to amino acids plus glucose is more than the sum of their individual effects Finally, acute anabolic responses in net MPS correspond quantitatively to differences in 24-h net muscle balances