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Biomedical subjects

G W Scott

Publications and source records attributed to G W Scott.

45 records · Page 3Linked to original sources
PubMed1975

Flow through the bile duct after cholecystectomy.

The human bile duct has no intrinsic motility, but following cholecystectomy, flow through the bile duct is governed by the intraductal pressure generated by the liver, by the resistance to flow through the duct and sphincter at the terminal end of bile duct and by intraduodenal pressure. Pressure-flow experiments were performed upon 50 patients with biliary T-tube drainage following cholecystectomy and choledochostomy; nine patients had also undergone transduodenal sphincterotomy. Saline solution was introduced into the bile duct at controlled pressures, ranging from zero to 30 centimeters of water, while recordings were made of the flow rate of saline solution, intraduodenal pressure and respiratory movements. Although the flow rate of saline solution increased as its perfusion pressure was increased, three types of variation in flow were also recorded: rhythmic arrests of flow, occurring four to eight times per minute, believed to be due sphincteric contractions; nonrhythmic arrests of flow, lasting up to one minute, believed to be due to sphincteric contraction, and variations in flow associated with changes in intraduodenal pressure. The resistance to the flow of saline solution and the variations in flow rate were also similar in the patients who had undergone sphincterotomy. This study supports the view that sphincteric activity is present followingcholecystectomy, that the choledochal sphincter has rhythmic activity which differs from that of duodenal motility and that sphincter probably opens and closes continuously in a rhythmic manner during fasting periods in patients who have undergone cholecystectomy.

Bile Ducts↗
PubMed1971

Exchange transfusion with dextran 40 in polycythaemia secondary to hypoxic lung disease.

In eight patients with polycythaemia secondary to hypoxic lung disease 10 elective exchange transfusions were performed to reduce red cell mass, packed cell volume (P.C.V.), and whole blood viscosity. The rationale for reducing P.C.V. is discussed. It is concluded that patients with P.C.V. of 60% or over will benefit from exchange transfusion and that most patients with P.C.V. over 50% and true polycythaemia will also benefit. We also confirm that the technique of exchange transfusion is a rapid, safe, and effective method of achieving large venesections and reducing red cell mass.

Aged↗
PubMedDate not supplied

Mucus hypersecretion in the gallbladder epithelium of ground squirrels fed a lithogenic diet for the induction of cholesterol gallstones.

This study identified mucus granules, determined mode of release and quantified their volume in the gallbladder epithelium of Richardson's ground squirrels (Spermophilus richardsonii) fed a lithogenic diet of 2% cholesterol to experimentally induce gallstone formation. Tissue was examined using light microscopy histochemistry, scanning and transmission electron microscopy, as well as autoradiography and morphometry at the electron microscopic level. Autoradiography demonstrated incorporation of a glycoprotein precursor, [3H]galactose, within the membrane-bound granules localized in the supranuclear region of the epithelial cells. Exocytosis of granule contents was by merocrine secretion. Morphometry indicated a significant increase in the amount of intracellular mucin granules as early as 18 hr on the lithogenic diet, a feature that continued throughout the experimental period of 20 weeks. Mucus synthesis/secretion rates returned to control values within 3 weeks after removal from the diet. Scanning electron microscopy observations revealed a thick sludge-like layer overlying the epithelium at a time in the chronology of the cholelithiasic model that correlated well with the initial phases of stone formation. Histochemistry showed this layer to be a mixture of acidic mucins. Neutral mucins were not observed. The hypersecretion of mucus and formation of this sludge-like layer appear to be critical nucleating factors in the formation of cholesterol gallstones.

Animals↗