1,088 research outputs found

    The Structure, Biosynthesis And Function Of Corticosteroid Binding Globulin

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    Corticosteroid binding globulin (CBG) is the major plasma transport protein for glucocorticoids. Complementary DNAs for rat, mouse, rabbit and squirrel monkey CBG were isolated, sequenced and their deduced primary structures were aligned. Overall, they exhibit 40.9% identity, and their comparison revealed conserved N-glycosylation sites and the probable position of the cysteine located within the human CBG steroid binding domain. Rat CBG mRNA is produced primarily by the liver, and in adults, males have two-thirds the CBG mRNA levels of females. During the last third of pregnancy, maternal hepatic CBG mRNA levels are relatively constant while fetal levels are highest at day 15 of gestation and decline to barely detectable levels at term. Concentrations of CBG mRNA are very low at birth, and adult values are attained by puberty. However, serum CBG concentrations do not reach adult levels until 6 weeks of age, and this is probably due to the relatively short half-life of CBG in infants (6.9 h) when compared to adults (14.5 h). Dexamethasone reduces rat serum CBG and hepatic CBG mRNA levels by 4 and {dollar}\u3e{dollar}26-fold, respectively, and the latter is the result of reduced CBG gene transcription. Thyroxine tends to increase serum CBG and hepatic CBG mRNA levels, but not CBG gene transcription. Sepsis reduces rat hepatic CBG mRNA levels to 11% of normal, and this is reflected by low serum CBG levels. Rat and human carriers of CBG variants with reduced cortisol binding activity have been identified, and sequence analysis of BioBreeding rat CBG cDNAs and exons of the human CBG gene revealed methionine{dollar}\sp{lcub}276{rcub}{dollar} to isoleucine{dollar}\sp{lcub}276{rcub}{dollar} and leucine{dollar}\sp{lcub}93{rcub}{dollar} to histidine{dollar}\sp{lcub}93{rcub}{dollar} substitutions in rat and human CBG, respectively. Scatchard analysis of media obtained from Chinese hamster ovary cells transfected with normal and mutant cDNAs for rat and human CBG confirms amino acid substitutions at these locations are responsible for reduced steroid binding affinity. Codons for other amino acids suspected to contribute to the steroid binding activity of human CBG have been mutated in vitro and the resulting cDNAs were expressed in culture. Analysis of these products should further contribute to our understanding of the relationship between CBG structure and function

    Quantitation of mitochondrial dynamics by photolabeling of individual organelles shows that mitochondrial fusion is blocked during the Bax activation phase of apoptosis

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    A dynamic balance of organelle fusion and fission regulates mitochondrial morphology. During apoptosis this balance is altered, leading to an extensive fragmentation of the mitochondria. Here, we describe a novel assay of mitochondrial dynamics based on confocal imaging of cells expressing a mitochondrial matrix–targeted photoactivable green fluorescent protein that enables detection and quantification of organelle fusion in living cells. Using this assay, we visualize and quantitate mitochondrial fusion rates in healthy and apoptotic cells. During apoptosis, mitochondrial fusion is blocked independently of caspase activation. The block in mitochondrial fusion occurs within the same time range as Bax coalescence on the mitochondria and outer mitochondrial membrane permeabilization, and it may be a consequence of Bax/Bak activation during apoptosis

    Proactive monitoring of pediatric hemodialysis vascular access: Effects of ultrasound dilution on thrombosis rates

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    Proactive monitoring of pediatric hemodialysis vascular access: Effects of ultrasound dilution on thrombosis rates.BackgroundHemodialysis vascular access thrombosis (VAT) is a significant cause of morbidity for hemodialysis patients and results, in part, from decreased access flow potentially caused by venous outflow stenosis. We have previously shown ultrasound dilution (UD) to be a practical and reliable predictor of venous outflow in children receiving hemodialysis.MethodsThe current study is the first to our knowledge to assess the impact of a proactive UD monitoring program upon VAT in pediatric patients. Nine patients experienced 18 VAT over the two-year study. Mean values for variables potentially associated with VAT were compared to values from a size-matched seven patient group without VAT during the study period. VAT rates were compared between the year-before (pre-UD era) and year-after (UD era) UD was initiated. During the latter half of the UD era (rapid referral period), patients with VA flow rate (QAcorr) <650 mL/min/1.73 m2 were referred for balloon angioplasty within 48 hours.ResultsMean QAcorr was lower for patients with subsequent VAT (562 ± 290 mL/min/1.73 m2) versus patients without VAT (1005 ± 372 mL/min/1.73 m2; P = 0.02). The VAT rate was significantly lower in the UD era (4.1 VAT/100 patient-months) versus the pre-UD era (11.0 VAT/100 patient-months; P = 0.03). The decrease in VAT rates was caused predominantly in the rapid referral period, where the VAT rate dropped to 0.96 VAT/100 patient-months (P < 0.001). Cost of vascular access management was 65% higher (1264vs.1264 vs. 765/patient-month) in the pre-UD era, reflecting the increased cost for treatment of VAT.ConclusionsMonthly QAcorr <650 mL/min/1.73 m2 is predictive of imminent VAT in children receiving hemodialysis. Prompt referral for angioplasty of VA with QAcorr <650 mL/min/1.73 m2 leads to decreased VAT rates in children

    Paper Session II-B - Application of Information Technology to the National Launch System

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    The information needs of the National Launch System program had their beginnings with the Advanced Launch System (ALS). The Technical Reference Document for ALS called for a Unified Information System (UNIS) to provide, in a timely manner, all the information required to manage, design, manufacture, integrate, test, launch, operate, and support the ALS. UNIS 9 was to provide the link between distributed, heterogeneous workstations which were to make up both the ground and flight information systems. In addition, there was to be an Advanced Launch System Model (ALSYM), a set of computerized submodels, or tools, which would work together to simulate all aspects of the ALS. These conceptual requirements were transitioned to the NLS program, and UNIS and the system simulation exist today. The current version of the NLS UNIS links geographically dispersed users to databases, analysis tools, program management tools, and communications devices. UNIS development is continuing to provide the ultimate capabilities which were described in the ALS Technical Reference Document. The approach to that development, as well as the current and planned capabilities are described. The ALSYM requirement transitioned as a requirement for a largescale, end-to-end simulation of the Space Transportation Main Engine (STME) development program, named STESYM. The approach being used to satisfy that requirement incorporates object-oriented programming, discrete-event simulation, and knowledge-based techniques to produce a simulation that captures the technical characteristics of the hardware, the processing flows, and the scheduling requirements. The outputs of the simulation will include subsystem and system reliabilities, process infrastructure statistics, schedule performance statistics, and costs. Together, UNIS and STESYM will provide program managers, engineers, logisticians, and other program participants with communications connectivity and the information to support STME program analysis

    The ventral epithelium of Trichoplax adhaerens deploys in distinct patterns cells that secrete digestive enzymes, mucus or diverse neuropeptides

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    © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Mayorova, T. D., Hammar, K., Winters, C. A., Reese, T. S., & Smith, C. L. The ventral epithelium of Trichoplax adhaerens deploys in distinct patterns cells that secrete digestive enzymes, mucus or diverse neuropeptides. Biology Open, 8, (2019): bio045674, doi:10.1242/bio.045674.The disk-shaped millimeter-sized marine animal, Trichoplax adhaerens, is notable because of its small number of cell types and primitive mode of feeding. It glides on substrates propelled by beating cilia on its lower surface and periodically pauses to feed on underlying microorganisms, which it digests externally. Here, a combination of advanced electron and light microscopic techniques are used to take a closer look at its secretory cell types and their roles in locomotion and feeding. We identify digestive enzymes in lipophils, a cell type implicated in external digestion and distributed uniformly throughout the ventral epithelium except for a narrow zone near its edge. We find three morphologically distinct types of gland cell. The most prevalent contains and secretes mucus, which is shown to be involved in adhesion and gliding. Half of the mucocytes are arrayed in a tight row around the edge of the ventral epithelium while the rest are scattered further inside, in the region containing lipophils. The secretory granules in mucocytes at the edge label with an antibody against a neuropeptide that was reported to arrest ciliary beating during feeding. A second type of gland cell is arrayed in a narrow row just inside the row of mucocytes while a third is located more centrally. Our maps of the positions of the structurally distinct secretory cell types provide a foundation for further characterization of the multiple peptidergic cell types in Trichoplax and the microscopic techniques we introduce provide tools for carrying out these studies.The work was supported by the Intramural Research Program of the National Institute of Neurological Disorders and Stroke and the National Institutes of Health

    Eat Smart Move More Weigh Less: A Community Based Weight Management Program for Adults

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    Describes development of a comprehensive, low cost weight management program to be delivered by local public health educators or cooperative extension agents. The program was developed by a unique partnerships of the NC Cooperative Extension Serive, the NC Division of Public Health and the Brody School of Medicine at East Carolina University

    Movement of Bax from the Cytosol to Mitochondria during Apoptosis

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    Bax, a member of the Bcl-2 protein family, accelerates apoptosis by an unknown mechanism. Bax has been recently reported to be an integral membrane protein associated with organelles or bound to organelles by Bcl-2 or a soluble protein found in the cytosol. To explore Bcl-2 family member localization in living cells, the green fluorescent protein (GFP) was fused to the NH2 termini of Bax, Bcl-2, and Bcl-XL. Confocal microscopy performed on living Cos-7 kidney epithelial cells and L929 fibroblasts revealed that GFP–Bcl-2 and GFP–Bcl-XL had a punctate distribution and colocalized with a mitochondrial marker, whereas GFP–Bax was found diffusely throughout the cytosol. Photobleaching analysis confirmed that GFP–Bax is a soluble protein, in contrast to organelle-bound GFP–Bcl-2. The diffuse localization of GFP–Bax did not change with coexpression of high levels of Bcl-2 or Bcl-XL. However, upon induction of apoptosis, GFP–Bax moved intracellularly to a punctate distribution that partially colocalized with mitochondria. Once initiated, this Bax movement was complete within 30 min, before cellular shrinkage or nuclear condensation. Removal of a COOH-terminal hydrophobic domain from GFP–Bax inhibited redistribution during apoptosis and inhibited the death-promoting activity of both Bax and GFP– Bax. These results demonstrate that in cells undergoing apoptosis, an early, dramatic change occurs in the intracellular localization of Bax, and this redistribution of soluble Bax to organelles appears important for Bax to promote cell death
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