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.

MRI contrast agents: basic chemistry and safety.

Abstract: Magnetic resonance imaging (MRI) contrast agents are pharmaceuticals used widely in MRI examinations. Gadolinium-based MRI contrast agents (GBCAs) are by far the most commonly used. To date, nine GBCAs have been commercialized for clinical use, primarily indicated in the central nervous system, vasculature, and whole body. GBCAs primarily lower the T(1) in vivo to create higher signal in T(1)-weighted MRI scans where GBCAs are concentrated. GBCAs are unique among pharmaceuticals, being water proton relaxation catalysts whose effectiveness is characterized by a rate constant known as relaxivity. The relaxivity of each GBCAs depends on a variety of factors that are discussed in terms of both the existing agents and future molecular imaging agents under study by current researchers. Current GBCAs can be divided into four different structural types (macrocyclic, linear, ionic, and nonionic) based on the chemistry of the chelating ligands whose primary purpose is to protect the body from dissociation of the relatively toxic Gd(3+) ion from the ligand. This article discusses how the chemical structure influences inherent and in vivo stability toward dissociation, and how it affects important formulation properties. Although GBCAs have a lower rate of serious adverse events than iodinated contrast agents, they still present some risk.

Hand grip strength and incident ADL disability in elderly Mexican Americans over a seven-year period

Abstract: Background and aims: Little is known about muscle strength as a predictor of disability among older Mexican Americans. The aim of this study was to examine the association between hand grip strength and 7-year incidence of ADL disability in older Mexican American men and women. Methods: A 7-year prospective cohort study of 2493 non-institutionalized Mexican American men and women aged 65 or older residing in five south-western states. Maximal hand grip strength test, body mass index, cognitive function, activities of daily living, self-reports of medical conditions (arthritis, diabetes, heart attack, stroke, cancer, hip fracture), and depressive symptoms were obtained. Results: In a Cox proportional regression analysis, there was a linear relationship between hand grip strength at baseline and risk of incident ADL disability over a 7-year follow-up. Among non-disabled men at baseline, the hazard ratio of any new ADL limitation was 1.90(95% CI 1.14–3.17) for those in the lowest quartile, when compared with men in the highest hand grip strength quartile, after controlling for age, marital status, medical conditions, high depressive symptoms, MMSE score, and BMI at baseline. Among non-disabled women at baseline, the hazard ratio of any new ADL limitation was 2.28 (95% CI 1.59–3.27) for those in the lowest quartile, when compared with women in the highest hand grip strength quartile. Conclusions: Hand grip strength is an independent predictor of ADL disability among older Mexican American men and women. The hand grip strength test is an easy, reliable, valid, inexpensive method of screening to identify older adults at risk of disability.

Atrophy and impaired muscle protein synthesis during prolonged inactivity and stress

Abstract: Context: We recently demonstrated that 28-d bed rest in healthy volunteers results in a moderate loss of lean leg mass and strength. Objective: The objective of this study was to quantify changes in muscle protein kinetics, body composition, and strength during a clinical bed rest model reflecting both physical inactivity and the hormonal stress response to injury or illness. Design: Muscle protein kinetics were calculated during a primed, continuous infusion (0.08 μmol/kg·min) of 13C6-phenylalanine on d 1 and 28 of bed rest. Setting: The setting for this study was the General Clinical Research Center at the University of Texas Medical Branch. Participants: Participants were healthy male volunteers (n = 6, 28 ± 2 yr, 84 ± 4 kg, 178 ± 3 cm). Intervention: During bed rest, hydrocortisone sodium succinate was administered iv (d 1 and 28) and orally (d 2–27) to reproduce plasma cortisol concentrations consistent with trauma or illness (∼22 μg/dl). Main Outcome Measures: We hypothesized that inactivity and hyp...