PubMed Health⌕ Search

Biomedical subjects

S D Wu

Publications and source records attributed to S D Wu.

7 recordsLinked to original sources
PubMed2005

New antimicrobial activity for the catecholamine release-inhibitory peptide from chromogranin A.

Catestatin (bCGA(344-364)), an endogenous peptide of bovine chromogranin A, was initially characterized for its effect on the inhibition of catecholamine release from chromaffin cells. Catestatin and its active domain (bCGA(344-358)) were identified in chromaffin cells and in secretion medium. The present study identified a potent antimicrobial activity of bCGA(344-358) in the lowmicromolar range against bacteria, fungi and yeasts, without showing any haemolytic activity. Confocal laser microscopy demonstrated penetration of the rhodaminated peptide into the cell membranes of fungi and yeasts and its intracellular accumulation. Time-lapse videomicroscopy showed arrest of fungal growth upon penetration of the labelled peptide into a fungal filament. We identified several catestatin-containing fragments in the stimulated secretion medium of human polymorphonuclear neutrophils, suggesting the N-terminal sequence of catestatin (bCGA(344-358)) (named cateslytin) as a novel component of innate immunity.

Amino Acid Sequence↗
PubMed2001

Demethylation metabolism of roxithromycin in humans and rats.

AIM: To investigate the demethylated metabolites of roxithromycin (RXM) in humans and rats, and to study the antibiotic activity of these metabolites in vitro. METHODS: The demethylated metabolites of RXM in humans and in rats were identified by liquid chromatography-mass spectrometry (LC-MS), and the in vitro antibiotic activities of them against three standard strains were also studied compared with those of the parent drug and some other metabolites of RXM. RESULTS: O-Demethylation of RXM was one of the main metabolic routes of RXM in humans, whereas N-demethylation metabolism was more predominant in rats. O-Demethyl-RXM appeared to be equally effective with RXM. CONCLUSION: The O-demethyl-RXM was an active metabolite in humans, and there were some species differences in RXM demethylation metabolism between humans and rats.

Adolescent↗
PubMed2000

Expression of estrogen receptor coactivators in the rat uterus.

Nuclear receptor coactivators associate in a ligand-dependent manner with estrogen receptors (ER) and other nuclear receptors, and they enhance ligand-dependent transcriptional activation. This study examined basal coactivator expression in rat uterus to investigate if expression of these genes is regulated by estradiol-17 beta or tamoxifen. Ovariectomized mature and immature rats were injected with estradiol-17 beta, tamoxifen, or vehicle (i.e., sesame oil) alone. Uteri were collected and analyzed for changes in coactivator mRNA expression using Northern blot and in situ hybridization analyses. Constitutive uterine mRNA expression of switch protein for antagonist (SPA), SRC-1, GRIP1, RAC3, RIP140, and p300 mRNAs was observed in control uteri, and treatment with ER ligands did not alter coactivator mRNA levels. The data suggest that expression of these coactivator genes is not sensitive to estradiol or tamoxifen in the rat uterus. No cell type-specific pattern of expression was apparent in uterine sections from mature and immature rats; however, silver grains were more abundant in luminal and glandular epithelial cells compared with the stroma and myometrium, indicating that coactivator mRNA levels vary among the uterine compartments. Thus, to our knowledge, we show for the first time that there is constitutive expression of several uterine nuclear receptor coactivators in a physiological setting that remains insensitive to estrogenic regulation. Furthermore, we speculate that higher constitutive levels of coactivator expression in glandular and luminal epithelial cells may be associated with increased hormonal responsiveness by these uterine compartments.

Adaptor Proteins, Signal Transducing↗