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G L Sharpe

Publications and source records attributed to G L Sharpe.

7 recordsLinked to original sources

Premature onset of labor, neonatal patent ductus arteriosus, and prostaglandin synthetase antagonists--a rat model of a human problem.

Premature labor and patent ductus arteriosus are two potentially fatal hazards of the human newborn infant. Prostaglandin synthetase antagonists have thus been used to suppress early labor and to close the ductus of the neonate. Indomethacin has been most effective but not free of significant complications. Neuronal necrosis may result from numerous systemic aberrations. A controlled rat model study was therefore devised to investigate fetal neuronal necrosis in relation to maternal indomethacin dose. Dams were given various treatments of 2 mg/kg of 4 mg/kg indomethacin within the last 3 days of gestation. Liquid chromatography was used to assess serum maternal and fetal drug levels. From light microscopy of more than 200 brains it was apparent that fetal neuronal necrosis correlates with maternal dose.

Animals

Studies on closure of the ductus arteriosus. XII. In utero effect of indomethacin and sodium salicylate in rats and rabbits.

Administration of prostaglandin synthetase inhibitors to pregnant does and dams in late gestation was followed by in utero contraction of the fetal ductus arteriosus when studied by the whole-body freezing method. In the rat this contraction was well established within 6 h and persisted up to 36 h following 15 mg/kg indomethacin p.o. No effect was observed in the 18 d rat fetus but fetuses at 20 d and 22 d of gestation responded significantly to indomethacin. Doses of indomethacin approaching clinical usage (2.5 mg/kg also caused a positive response in utero. The rat was found to be sensitive also to sodium salicylate and in the rabbit both indomethacin and sodium salicylate were effective. Exposure in utero to prostaglandin synthetase inhibitors with resulting contraction of the ductus may seriously disturb cardiac function in the fetus.

Animals

Studies on closure of the ductus arteriosus. X. In vivo effect of prostaglandin.

The effect of prostaglandins F2alpha, E1 and of 7-oxa-13-prostynoic acid on the newborn rabbit ductus can be studied using the whole-body freezing technique. PGF2alpha and PGE1 were able to re-open the closing ductus arteriosus in adequately oxygenated animals. PGF2alpha administration was accompanied by a strong physical reaction in the rat but less in the rabbit. PGE1 had sedative effects in both animals. A prostaglandin antagonist, 7-oxa-13-prostynoic acid had no effect on normal ductal closure nor did it counteract the effects of PGF2alpha and PGE1. The role of prostaglandins in homeostasis during the fetal and newborn period may be to modify ductal tone.

Animals