Search PubMed⌕ Search

Biomedical subjects

M M Thaler

Publications and source records attributed to M M Thaler.

105 records · Page 6Linked to original sources
PubMed1969

Actinomycin D: uptake by sea urchin eggs and embryos.

Actinomycin D is excluded from unfertilized eggs and developing embryos of the sea urchin Arbacia punctulata until the blastula hatches. The rate of uptake of actinomycin D by embryos doubles as development progresses after hatching to the gastrula stage.

Animals↗
PubMedDate not supplied

Regulation of bile salt sulfotransferase isoenzymes by gonadal hormones.

We studied the regulation of hepatic bile salt sulfotransferase activity by gonadal hormones and the effect of gonadal hormones on two bile salt sulfotransferase isoenzymes. Bile salt sulfotransferase enzyme activity was three times greater in the female than in the male rats. Oophorectomy significantly decreased bile salt sulfotransferase activity in the female, but orchidectomy had no effect on bile salt sulfotransferase activity in the male. Estrogen treatment of intact as well as orchidectomized males markedly stimulated the enzyme activity, while testosterone treatment of intact or oophorectomized females did not effect bile salt sulfotransferase activity. We concluded that the 3-fold greater activity in female rats is due to the striking stimulatory effect of estrogen on bile salt sulfotransferase activity, and the testosterone has little or no role in the sexually related differences in bile salt sulfotransferase activity in mature rats. These sex-related differences in bile salt sulfotransferase activity were investigated further using DEAE-Sephadex A50 ion-exchange chromatography of rat hepatic cytosol. Two bile salt sulfotransferase isoenzymes were identified both with an approximate molecular weight of 130,000. Bile salt sulfotransferase I eluted with 0.05 M NaCl, had an isoelectric point at pH 6.8, was stimulated by estrogen, and was responsible for 90% of total bile salt sulfotransferase activity in the mature female. Bile salt sulfotransferase II eluted with 0.14 M NaCl, had an isoelectric point at pH 5.3, was unresponsive to estrogen, and accounted for 75 to 80% of bile salt sulfotransferase activity in the mature male.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Endoscopic retrograde cholangiography in the diagnosis of biliary malformations in infants.

The differentiation of infantile biliary malformations from primary parenchymal diseases is difficult. The recent development of a pediatric side-viewing endoscope (PJF Endoscope; Olympus Corporation of America) provided an opportunity to investigate the usefulness of endoscopic retrograde cholangiography (ERC) for precise visualization of the extrahepatic biliary passages in infants with persistent cryptogenic cholestasis. ERC was performed in 12 patients, with visualization of the existing extrahepatic bile ducts in 4. The entire biliary system was visualized in one, excluding extrahepatic biliary atresia and choledochal cyst. The reduced caliber of the intrahepatic bile ducts and histological observations in a percutaneous liver biopsy supported the diagnosis of intrahepatic biliary hypoplasia in this case. An intact hepatic portochole cystostomy was documented in one, although the intrahepatic biliary system was not delineated. Atresia of the hepatic bile ducts proximal to the gallbladder was documented in two. Of the eight patients in whom extrahepatic bile ducts were not visualized by ERC, six had extrahepatic biliary atresia confirmed at exploratory laparotomy. The papilla of Vater could not be located in four of these six infants. The remaining two had neonatal hepatitis. ERC may offer a useful alternative to operative cholangiography in selected infants with persistent cholestasis and acholic stools.

Biliary Atresia↗