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Biomedical subjects

S Huang

Publications and source records attributed to S Huang.

At least 667 records · Page 37Linked to original sources
PubMed1986

Canine basilar artery contractions mediated by 5-hydroxytryptamine1A receptors.

A series of 11 agents was analyzed at both 5-hydroxytryptamine1A (5-HT1A) sites labeled by [3H]-8-hydroxy-2-(N,N-dipropylamino)tetralin and total 5-HT1 binding sites labeled by [3H]-5-HT in rat brain membranes. Three distinct patterns of relative inhibition were noted. First, drugs such as 8-hydroxy-2-(N,N-dipropylamino)tetralin n-(3-acetylaminophenyl)piperazine hydrochloride, 2-[4-[4-(2-pyrimidinyl)-1-piperazinyl]-1,2-benziso-thiazol-3 -(2H)one-1,1-dioxidehydrochloride] and buspirone display 1.0 to 15 nM potency for the 5-HT1A subpopulation of 5-HT1 binding sites but are more than two orders of magnitude less potent at total 5-HT1 sites. Secondly, 5-methoxy-N,N-dimethyltryptamine and methysergide are approximately one order of magnitude more potent at 5-HT1A than total 5-HT1 sites. In the third group, 5-HT, d-lysergic acid diethylamide, 1-(m-trifluoromethylphenyl)piperazine, 5-methoxy-3-(1,2,3,6-tetrahydro-4-pyrimidinyl) 1H indole, quipazine and pirenperone are essentially equipotent at both 5-HT1A and 5-HT1 sites. Thus, the 5-HT1A binding site has a pharmacological profile which, depending on the agents studied, could be significantly different from the pharmacological profile derived from total 5-HT1 binding. Drug interactions were also analyzed with canine basilar artery segments using 5-HT, 10 putative serotonergic agonists and a selective 5-HT2 antagonist, pirenperone. The maximal contraction was obtained using 5-HT (Cmax = 6.6 +/- 0.6 g). However, each of the 10 other putative 5-HT agonists elicited a less forceful contraction of the canine basilar artery.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1985

Neurite outgrowth traced by means of horseradish peroxidase inherited from neuronal ancestral cells in frog embryos.

Outgrowing neurites in Xenopus embryos were labeled with horseradish peroxidase which had been injected into a single blastomere at the 32-cell stage and had been inherited by all the descendants, including neurons. Neurite outgrowth was traced from labeled trigeminal ganglion cells and most or all types of neurons present in the spinal cord at embryonic stages 20-30: primary motoneurons, commissural, dorsal longitudinal, ventral longitudinal, and Rohon-Beard neurons. All types of nerve fibers grew by the most direct pathway, apparently without errors of initial outgrowth, pathway selection, or target selection. An initial transient phase of outgrowth of filopodial processes from neuronal cell bodies and shafts of short neurites was observed which disappeared after further elongation of the neurites. The first pioneer fibers grew out from all types in a 2-hr period, from stage 20 to 22, and these fibers arrived at the targets within 3.5 hr after initial outgrowth. Additional fibers grew later in contact with the pioneers to form fascicles. Nerve fibers elongated without branching until they neared or contacted their targets. The rate of elongation at 20 degrees C was 30-75 micron/hr. The rapid, unbranched, error-free initial outgrowth and elongation of neurites to their targets is discussed in relation to theories of development of nerve pathways.

Animals↗
PubMed1984

Phenotypic heterogeneity in Huntington disease.

Two Huntington disease (HD) pedigrees are presented which differ according to mean and distribution of the age at onset, the effect of paternal transmission on the age at onset, presence of manic-depressive symptoms, and type of presenting symptoms. Together with previous reports, the data suggest clinical heterogeneity between HD kindreds which may imply some kind of genetic heterogeneity, most likely subsequent mutation at a single HD locus. The possibility of genetic heterogeneity has important consequences, both in research, and in the counseling and care of families and patients with differing manifestations of the disease.

Adult↗
PubMed1984

Characterization and culture of sinusoidal endothelium from normal rat liver: lipoprotein uptake and collagen phenotype.

Sinusoidal endothelial cells from adult rat liver have been isolated by centrifugal elutriation and been established in primary culture. Their identification has made use of a novel process of these cells, the sequestration of human acetoacetylated low-density lipoprotein. After its administration in vivo, labeled acetoacetylated low-density lipoprotein within the liver was associated solely with sinusoidal endothelial cells and, when labeled with the stable fluorescent compound 3,3'-dioctadecylindocarbocyanine, provided a means of identifying isolated cells by fluorescence microscopy. In endothelial cell cultures, 90% of the cells were fluorescent and exhibited fenestrae. The collagen phenotype of cultures was assessed by an immunofluorescent approach, which revealed cell-associated type IV collagen only; types I, III, and V were undetectable. In other studies, it was found that these cells lacked factor VIII-R antigen and Weibel-Palade bodies, adding to the evidence that they differ substantially from large-vessel and other capillary endothelia.

Animals↗
PubMed1983

Amino acid sequence studies on lactate dehydrogenase C4 isozymes from mouse and rat testes.

Carboxymethylated sperm-specific lactate dehydrogenase isozyme C4 (LDH-C4) proteins from mouse and rat testes were cleaved with cyanogen bromide and trypsin. Proteins were also citraconylated and digested with trypsin. In the case of mouse LDH-C4 isozyme, all 7 CNBr and 11 limited tryptic (arginine) peptides were isolated and sequenced. Some of the CNBr peptides were further fragmented with trypsin and chymotrypsin and their compositions and/or sequences characterized. Also, 34 of the 36 expected tryptic peptides were purified, and their compositions and sequences determined. Amino acid sequences of these peptides purified from mouse LDH-C4 were overlapped into a complete covalent structure of the 330 residues. For rat LDH-C4, 5 of 6 expected CNBr peptides, 5 of 8 expected arginine peptides, and 28 of the 34 expected tryptic peptides were isolated, and their compositions and sequences were determined. Some of the CNBr and arginine peptides were further fragmented with chymotrypsin, thermolysin, or V8 protease, and their compositions and/or sequences characterized. The amino acid sequence of 85% of the 330 residues from rat LDH-C subunit has been unambiguously determined, and the sequences of the remaining regions were tentatively aligned on the basis of peptide compositions and sequence homologies with the other known lactate dehydrogenase sequences, including mouse LDH-C. A comparison of the proposed rat LDH-C sequence with the complete covalent structure of mouse LDH-C indicates that 27 differences are located in the established rat LDH-C sequence of 280 residues and that 5 additional differences are in the tentative sequence of the remaining 50 amino acids.

Amino Acid Sequence↗
PubMed1983

Autoradiographic localization of target cells for 1 alpha, 25-dihydroxyvitamin D3 in bones from fetal rats.

Thaw-mount autoradiographic studies after injection of 3H-1,25-D3 were conducted on 18- and 20-day-old rat fetuses. In maxillary bones, ribs, and tibia, nuclear concentration of radioactivity was found in osteoprogenitor cells and osteoblasts. Osteocytes and chondrocytes in epiphyseal plates were either unlabeled or weakly labeled. In competition experiments, nuclear concentration of radioactivity was blocked by the injection of a high dose of nonradioactive 1,25-D3 prior to the administration of the labeled hormone, but not by a similar dose of nonradioactive 25-D3. The results are interpreted as indicating that osteoprogenitor cells and osteoblasts are target cells for the direct action of 1,25-D3 on fetal bone.

Animals↗
PubMed1983

Autoradiographic localization of 1,25-dihydroxyvitamin D3 in rat placenta and yolk sac.

After injection of 3H-1,25-(OH)-vitamin D3 into rats on days 18 and 20 of pregnancy, autoradiograms of placenta and fetal membranes show nuclear concentration of radioactivity in certain cells. This nuclear concentration is abolished when unlabeled 1,25-(OH)2-vitamin D3, but not 25-(OH)-vitamin D3, is injected prior to the labeled hormone. Nuclear labeling is observed in epithelial cells of visceral yolk sac and amnion, and in certain trophoblasts in basalis and labyrinth. The results suggest the presence of a specific receptor-like binding for 1,25-(OH)2-vitamin D3 and thus involvement of the target cells in calcium regulatory mechanisms during development.

Animals↗
PubMed1981

Autoradiographic studies with 3H 1,25 (OH)2 vitamin D2 and 3H 25 (OH) vitamin D3 in rat parathyroid glands.

After injection of radiolabeled 1,35 (OH)s vitamin D3, nuclear concentration of radioactivity is observed in parenchymal cells o hte parathyroid gland in pregnant, adult male, and 10-day male neonatal rats. In competition studies with unlabeled 1,25 (OH)2 vitamin D3, but not with 25 (OH) vitamin D3, in contrast to 3H 1,25 (OH)2 vitamin D3, do not show nuclear concentration in cells of te parathyroid. The results of te autoradiographic studies suggest the presence of receptors for a direct effect of 1,35 (OH)2 vitamin D3 on the parathyroid gland for modulation of parathyroid hormone secretion.

Aging↗
PubMed1981

Serum pseudocholinesterase: high density lipoprotein cholesterol ratio as an index of risk for cardiovascular disease.

A significant increase in the ratio of serum pseudocholinesterase/high density lipoprotein cholesterol (the Complementary Risk Factor ratio) was found in individuals classified as high risk for cardiovascular disease on the basis of the ratio of total cholesterol/high density lipoprotein cholesterol (the Established Risk Factor ratio) compared to the individuals with average and low risks. This Complementary Risk Factor ratio also showed good correlation with serum low density lipoprotein, triglycerides and the Established Risk Factor ratio. These results indicate that serum cholinesterase has a parallel relationship with low density lipoproteins and a reciprocal relationship with high density lipoproteins. We propose that the Complementary Risk Factor ratio may be an additional marker in predicting the risks for cardiovascular disease.

Butyrylcholinesterase↗
PubMed1981

1,25-Dihydroxyvitamin D3 target cells in rat mammary gland.

In autoradiograms of mammary glands of rats on days 18 and 20 of pregnancy and day 6 of lactation after injection of 3H 1,25-(OH)2 vitamin D3, a nuclear concentration of radioactivity is observed in alveolar and ductal cells, as well as in cells of the epidermis of the nipple. Myoepithelial cells and connective tissue cells do not concentrate the hormone in their nuclei. The nuclear radioactivity appears specific, since 1,25-(OH)2 vitamin D3 but not 25-(OH)2 vitamin D3 prevents the uptake. The results suggest the existence of nuclear receptors for 1,25-(OH)2 vitamin D3 in mammary tissues and thus complements previous biochemical evidence showing the presence of cytoplasmic receptors for the hormone in mouse mammary glands; in addition, our results allow the identification of the cell types possessing the receptors.

Animals↗