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.

Resistance of SARS-CoV-2 variants to neutralization by monoclonal and serum-derived polyclonal antibodies.

Abstract: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the global COVID-19 pandemic. Rapidly spreading SARS-CoV-2 variants may jeopardize newly introduced antibody and vaccine countermeasures. Here, using monoclonal antibodies (mAbs), animal immune sera, human convalescent sera and human sera from recipients of the BNT162b2 mRNA vaccine, we report the impact on antibody neutralization of a panel of authentic SARS-CoV-2 variants including a B.1.1.7 isolate, chimeric strains with South African or Brazilian spike genes and isogenic recombinant viral variants. Many highly neutralizing mAbs engaging the receptor-binding domain or N-terminal domain and most convalescent sera and mRNA vaccine-induced immune sera showed reduced inhibitory activity against viruses containing an E484K spike mutation. As antibodies binding to spike receptor-binding domain and N-terminal domain demonstrate diminished neutralization potency in vitro against some emerging variants, updated mAb cocktails targeting highly conserved regions, enhancement of mAb potency or adjustments to the spike sequences of vaccines may be needed to prevent loss of protection in vivo.

Increased rates of muscle protein turnover and amino acid transport after resistance exercise in humans

Abstract: The rates of protein synthesis and degradation and of amino acid transport were determined in the leg muscle of untrained postabsorptive normal volunteers at rest and approximately 3 h after a resistance exercise routine. The methodology involved use of stable isotopic tracers of amino acids, arteriovenous catheterization of the femoral vessels, and biopsy of the vastus lateralis muscle. During postexercise recovery, the rate of intramuscular phenylalanine utilization for protein synthesis increased above the basal value by 108 +/- 18%, whereas the rate of release from proteolysis increased by 51 +/- 17%. Muscle protein balance improved (P < 0.05) after exercise but did not become positive (from -15 +/- 12 to -6 +/- 3 nmol phenylalanine.min-1.100 ml leg volume-1). After exercise, rates of inward transport of leucine, lysine, and alanine increased (P < 0.05) above the basal state from 132 +/- 16 to 208 +/- 29, from 122 +/- 8 to 260 +/- 8, and from 384 +/- 71 to 602 +/- 89 nmol.min-1.100 ml leg-1, respectively. Transport of phenylalanine did not change significantly. These results indicate that, during recovery after resistance exercise, muscle protein turnover is increased because of an acceleration of synthesis and degradation. A postexercise acceleration of amino acid transport may contribute to the relatively greater stimulation of protein synthesis.

Comparison of strategies for sustaining weight loss: the weight loss maintenance randomized controlled trial.

Abstract: Context Behavioral weight loss interventions achieve short-term success, but re-gain is common. Objective To compare 2 weight loss maintenance interventions with a self-directed control group. Design, Setting, and Participants Two-phase trial in which 1032 overweight or obese adults (38% African American, 63% women) with hypertension, dyslipidemia, or both who had lost at least 4 kg during a 6-month weight loss program (phase 1) were randomized to a weight-loss maintenance intervention (phase 2). Enrollment at 4 academic centers occurred August 2003-July 2004 and randomization, February-December 2004. Data collection was completed in June 2007. Interventions After the phase 1 weight-loss program, participants were randomized to one of the following groups for 30 months: monthly personal contact, unlimited access to an interactive technology–based intervention, or self-directed control. Main Outcome Changes in weight from randomization. Results Mean entry weight was 96.7 kg. During the initial 6-month program, mean weight loss was 8.5 kg. After randomization, weight regain occurred. Participants in the personal-contact group regained less weight (4.0 kg) than those in the self-directed group (5.5 kg; mean difference at 30 months, −1.5 kg; 95% confidence interval [CI], −2.4 to −0.6 kg; P = .001). At 30 months, weight regain did not differ between the interactive technology–based (5.2 kg) and self-directed groups (5.5 kg; mean difference −0.3 kg; 95% CI, −1.2 to 0.6 kg; P = .51); however, weight regain was lower in the interactive technology–based than in the self-directed group at 18 months (mean difference, −1.1 kg; 95% CI, −1.9 to −0.4 kg; P = .003) and at 24 months (mean difference, −0.9 kg; 95% CI, −1.7 to −0.02 kg; P = .04). At 30 months, the difference between the personal-contact and interactive technology–based group was −1.2 kg (95% CI −2.1 to −0.3; P = .008). Effects did not differ significantly by sex, race, age, and body mass index subgroups. Overall, 71% of study participants remained below entry weight. Conclusions The majority of individuals who successfully completed an initial behavioral weight loss program maintained a weight below their initial level. Monthly brief personal contact provided modest benefit in sustaining weight loss, whereas an interactive techonology–based intervention provided early but transient benefit. Trial Registration clinicaltrials.gov Identifier: NCT00054925

Activation of caspase-3 is an initial step triggering accelerated muscle proteolysis in catabolic conditions

Abstract: With trauma, sepsis, cancer, or uremia, animals or patients experience accelerated degradation of muscle protein in the ATP-ubiquitin-proteasome (Ub-P'some) system. The initial step in myofibrillar proteolysis is unknown because this proteolytic system does not break down actomyosin complexes or myofibrils, even though it degrades monomeric actin or myosin. Since cytokines or insulin resistance are common in catabolic states and will activate caspases, we examined whether caspase-3 would break down actomyosin. We found that recombinant caspase-3 cleaves actomyosin, producing a characteristic, approximately 14-kDa actin fragment and other proteins that are degraded by the Ub-P'some. In fact, limited actomyosin cleavage by caspase-3 yields a 125% increase in protein degradation by the Ub-P'some system. Serum deprivation of L6 muscle cells stimulates actin cleavage and proteolysis; insulin blocks these responses by a mechanism requiring PI3K. Cleaved actin fragments are present in muscles of rats with muscle atrophy from diabetes or chronic uremia. Accumulation of actin fragments and the rate of proteolysis in muscle stimulated by diabetes are suppressed by a caspase-3 inhibitor. Thus, in catabolic conditions, an initial step resulting in loss of muscle protein is activation of caspase-3, yielding proteins that are degraded by the Ub-P'some system. Therapeutic strategies could be designed to prevent these events.