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.

Glucose plus insulin regulate fat oxidation by controlling the rate of fatty acid entry into the mitochondria.

Abstract: We tested the hypothesis that glucose plus insulin determine the rate of fat oxidation in humans by controlling the rate of fatty acid entrance into the mitochondria. We gave constant infusions of [1-13C]oleate, a long-chain fatty acid, and [1-14C]octanoate, a medium-chain fatty acid, for 3 h in seven volunteers (basal). Immediately after the basal period, a hyperinsulinemic (insulin infusion = 120 mU x m(-2) min(-1)), hyperglycemic (plasma glucose = 140 mg/dl) clamp was started and continued for 5 h. During the last 3 h of the clamp, the infusions of [1-13C]oleate and [1-14C]octanoate were repeated. Intracellular acylcarnitine concentrations were measured in muscle biopsies obtained before and after the clamp. Plasma oleate enrichment and FFA concentration were kept constant by means of variable infusions of lipids and heparin. Oleate, but not octanoate, requires carnitine binding to gain access to the mitochondrial matrix; hence, if glucose and/or insulin limit long-chain fatty acid entrance into the mitochondria, then, during the clamp, long-chain acylcarnitine formation should be decreased, causing a decrease in oleate, but not octanoate, oxidation. Oleate oxidation decreased from the basal value of 0.7+/-0.1 to 0.4+/-0.1 micromol x kg(-1) x min(-1) (P < 0.05). In contrast, octanoate oxidation remained unchanged. Long-chain acylcarnitine concentration decreased from 855+/-271 in the basal state to 376+/-83 nmol/gram dry weight during the clamp (P < 0.05). We conclude that glucose and/or insulin determine fatty acid oxidation by controlling the rate of long-chain fatty acid entrance into the mitochondria.

Peripheral inflammation sensitizes P2X receptor-mediated responses in rat dorsal root ganglion neurons.

Abstract: ATP-gated P2X receptors in nociceptive sensory neurons participate in transmission of pain signals from the periphery to the spinal cord. To determine the role of P2X receptors under injurious conditions, we examined ATP-evoked responses in dorsal root ganglion (DRG) neurons isolated from rats with peripheral inflammation, induced by injections of complete Freund's adjuvant (CFA) into the hindpaw. Application of ATP induced both fast- and slow-inactivating currents in control and inflamed neurons. CFA treatment had no effect on the affinity of ATP for its receptors or receptor phenotypes. On the other hand, inflammation caused a twofold to threefold increase in both ATP-activated currents, altered the voltage dependence of P2X receptors, and enhanced the expression of P2X2 and P2X3 receptors. The increase in ATP responses gave rise to large depolarizations that exceeded the threshold of action potentials in inflamed DRG neurons. Thus, P2X receptor upregulation could account for neuronal hypersensitivity and contribute to abnormal pain responses associated with inflammatory injuries. These results suggest that P2X receptors are useful targets for inflammatory pain therapy.

Developmental features of the neonatal brain: MR imaging. Part I. Gray-white matter differentiation and myelination.

Abstract: To establish the normal appearance of the neonatal brain, 51 neonates, 29-42 weeks postconception, underwent magnetic resonance (MR) imaging with a 0.6-T magnet in a prospective study. T1-weighted images were used to devise stages for the appearance of gray-white matter differentiation and extent of myelination. The results show that from 29 to 42 weeks postconception, changes in gray-white matter differentiation and myelination follow the stages in an orderly and predictable fashion. Changes in white matter intensity appear related to progressive decrease in brain water content. Myelination progresses cephalad from the brain stem at 29 weeks to reach the centrum semiovale by 42 weeks. Delayed myelination, defined as the absence of myelin in the corona radiata by 37 weeks, was seen in nine infants with complicated perinatal courses. Awareness of these developmental features should help to minimize misinterpretation of normal changes in the neonatal brain and lead to earlier detection of pathologic conditions, both with MR imaging and computed tomography.

Respiratory Syncytial Virus–Induced Activation of Nuclear Factor–κB in the Lung Involves Alveolar Macrophages and Toll-Like Receptor 4–Dependent Pathways

Abstract: The transcription factor nuclear factor (NF)-kappaB controls the expression of numerous respiratory syncytial virus (RSV)-inducible inflammatory and immunomodulatory genes. Using a BALB/c mouse model, the present article shows that RSV potently and specifically activates NF-kappaB in vivo, a process that involves nuclear translocation of the subunits RelA, p50, and c-Rel in the lung. By depletion of alveolar macrophages (AMs) in BALB/c mice and use of C3H/HeJ mice lacking a functional Toll-like receptor (TLR)-4 signaling pathway, we demonstrate the existence of distinct but sequentially integrated RSV-inducible early NF-kappaB responses in the lung. The first response occurs early after RSV inoculation, is AM and TLR4 dependent, and is viral replication independent, whereas the second response involves epithelial cells and/or inflammatory cells, is TLR4 independent, and requires viral replication. NF-kappaB may be considered a central activator of not only inflammatory but also innate immune responses to RSV.

Cold-labile and cold-stable microtubules in the mitotic spindle of mammalian cells.

Abstract: The lability of microtubules to a variety of chemical and physical agents has been extensively documented in numerous plant and animal cells. Some microtubules may be completely disrupted by such agents as colchicine, vinca alkaloids, hydrostatic pressure, or cold temperatures, whereas other tubules within the same cellular environment remain intact. In an earlier study, Behnke and Forer identified four classes of microtubules in insect spermatids based on their disruption by colchicine, trypsin, and cold temperatures. Subsequently, similar observations were reported in other spermatids.7. Tihey and GibbinsZG observed differential effects of a variety of antimitotic agents on cytoplasmic and ciliary microtubules of sea urchin gastrulae. Differences in solubility of A and B subtubules within the axoneme have also been well known.24 The disruptive effects o f cold temperatures on the mitotic spindle have been reported by numerous investigators, but there have been no reports of differential effects on spindle fibers. The first observation of cold on the mitotic process in living cells was provided by Inou6.101 l1 Rapid but reversible loss of spindle birefringence was apparent when marine eggs were subjected to cold temperatures. More recently, Sat0 ?? has provided quantitative evidence that spindle birefringence is due largely, if not entirely, to microtubules. Therefore, the loss of birefringence due to cold would suggest complete disruption of microtubules within the spindle. Further confirmation of InouC's observation was provided by Roth,?O who observed general disruption of spindle microtubules of the giant amoeba after cold treatment. Electron microscopic studies in our laboratory utilizing mammalian cells have indicated that certain microtubules of the mitotic apparatus (MA) are more resistant to cold disruption than are others. In the present study we report on direct microtubule counts from fibroblast of the cells of rat kangaroo (strain PtK,) at metaphase, anaphase, and telophase, using transverse serial-section analysis as described in an earlier study.4 Comparison of spindle microtubule profiles of cells grown at 37°C with cells chilled for 30 min in an ice bath