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Biomedical subjects

H Hall

Publications and source records attributed to H Hall.

208 records · Page 12Linked to original sources
PubMed1975

Distribution of an adenohypophysial constituent in the body. II. Quantitative tissue distribution in the rat.

A peptide with a molecular weight of about 5000 has previously been shown to affect the output of semen in frogs and probably also in mammals. This sperm-releasing substance is not part of any known gonadotropic hormone. The tissue distribution of this substance has been investigated. The iodinated substance has been injected into rats and the radioactivity content of the different tissues has been determined. Iodinated rat albumin has been injected into other rats, to determine the content of blood in the different tissues. A formula has been derived to obtain a figure for real accumulation, using the radioacitivity content of the blood and of the tissues after injection of the sperm-releasing substance and albumin, respectively. The sperm-releasing substance is incorporated into the adenohypophysis, neurohypophysis, liver, kidney, lung, ovary, uterus and some male sexual organs. The causes for this distribution are discussed.

Animals↗
PubMedDate not supplied

Inhibition of the proteasome reduces transfer-induced diabetes in nonobese diabetic mice.

Inhibition of the 26S proteasome reduces the severity of several immune-mediated diseases. Here, we report that the proteasome also regulates transfer-induced diabetes in nonobese mice. Treatment of recipient mice with the proteasome inhibitor N(alpha)-benzyloxycarbonyl-l-leucyl-l-leucyl-l-leucinal (MG132) resulted in a 76% reduction in transfer-induced diabetes. The closely related inhibitor carbobenzoxy-l-leucyl-l-leucinal that inhibits calpains but not the proteasome had no protective effect, suggesting that MG132 acted via inhibition of the proteasome. MG132 decreased proliferation of transferred T cells in the pancreatic lymph nodes in vivo and prevented their expansion in a dose-dependent manner in vitro, consistent with a direct effect by MG132 on the T cells. MG132 did not prevent migration of transferred T cells into the islets but reduced the number of mice with severe infiltration. We suggest that MG132 prevents transfer-induced diabetes by directly targeting the autoreactive T cells and lowering their diabetogenic potential.

Adoptive Transfer↗
PubMedDate not supplied

Serotonin receptors in the brain following total hepatectomy in rats treated with branched-chain amino acids.

Serotonin concentrations and receptor binding characteristics were investigated in rats subjected to total hepatectomy, portacaval shunt (PCS) or sham-operation. The animals were infused for 5 hr with a 10% glucose solution or the same solution enriched with 0.24 M branched-chain amino acids (BCAA). Hepatectomized animals were in grade-two coma at the end of the experiment independent of infusion. Indoleamines in mesencephalon-pons and diencephalon were analyzed by high-pressure liquid chromatography with electrochemical detection. Serotonin receptors (5-HT1 and 5-HT2) were investigated in the cortex and hippocampus by radioligand binding studies using 3H-serotonin for analysis of 5-HT1-receptors and 3H-ketanserin for analysis of 5-HT2-receptors. Concentrations of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were significantly increased after hepatectomy compared with controls. Treatment with BCAA significantly decreased 5-HT and 5-HIAA levels in hepatectomized animals. The affinity and the number of binding sites for the 5-HT1 and 5-HT2 receptors were found to be similar in all groups. The present study indicates that PCS for 1 week and the anhepatic state for 5 hr in rats do not influence brain serotonin receptors in contrast to previous studies in pigs with liver ischemia or rabbits with galactosamine-induced liver damage. In addition, infusion of BCAA for 5 hr did not alter the binding characteristics.

Amino Acids, Branched-Chain↗
PubMedDate not supplied

The psychophysiology of voluntary immunomodulation.

In twenty-two studies of intentional effects of humans to change immune measures, only four monitored psychophysiologic parameters. One study reported physiologic alterations associated with immune changes. In this current study we examined changes in pulse rate and peripheral temperature associated with intentional changes in neutrophil adherence. Subjects had blood, pulse and temperature recordings collected before and after either a rest condition (Group A), or a self-regulation exercise (Groups B and C) for two sessions. Group C had four prior training sessions before participating in the experimental sessions. This study found no association between psychophysiologic alterations and neutrophil changes. The control group (A) demonstrated no significant neutrophil changes but showed physiologic alterations, whereas, the experimental group (C) that showed increases in neutrophil adherence demonstrated no significant physiologic changes. It was speculated that intentional changes on neutrophil adherence and the pattern of the psychophysiologic measures were associated with and reflective of cognitive activity.

Adolescent↗
PubMedDate not supplied

Inhibition of endocytic transport by aluminum fluoride implicates GTPases as regulators of endocytosis.

It is now well established that GTP-binding proteins are important regulators of vesicular transport. Recent work has shown that multiple GTPases (both monomeric and heterotrimeric) are required for trafficking. In the present study we have used aluminum fluoride (AIF), a reagent that activates trimeric G proteins, as a tool to study the involvement of this family of GTPases in the regulation of endocytosis in intact cells. Our results indicate that AIF inhibits fusion of early endosomes with an intracellular proteolytic compartment. Using the mixing of sequentially internalized ligands as a measure of endocytosis, we found that AIF inhibited endocytic transport as assessed by both biochemical and morphological methods. Taken together these results suggest that AIF affects membrane fusion, a common step in vesicular transport. To further examine the effects of AIF we tested this compound in a cell-free assay that reconstitutes fusion among endosomes. AIF affected endosomal fusion in a different way than did GTP gamma S, an agent that activates both trimeric and small GTPases. Our results suggest that the coordinated activation of both classes of GTPases are required for efficient endocytic transport.

Aluminum Compounds↗