Biomedical subjects
Publications and source records attributed to C S Brown.
Various types of drains were inserted into the peritoneal cavity of twenty-eight dogs. After one to seven days, all drains failed to show the presence of 200 cc of colored fluid injected intraperitoneally. On autopsy, all tubes were surrounded and occluded by omentum.
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A population of 98 fourth and fifth grade students responded to instruments that yielded data on social acceptance, liking for others, need for approval, and interpersonal relationship orientation. Results suggest that social acceptance is related to interpersonal relationship orientation, but unrelated to liking for others and need for approval. Implications for treatment are discussed.
Twelve dogs were subjected to hemorrhagic shock by means of a modified Wiggers technique. Half were treated with prostaglandin E1, 1 microgram per kilogram per minute in 60 milliliters of saline solution, for one hour after shock, while the other half received only an equal amount of saline solution. Those dogs treated with prostaglandin E1 exhibited a significantly increased survival time and cardiac output as well as a significantly lowered total peripheral resistance when compared with those for untreated dogs. The various modes of action by which prostaglandin E1 exerts both its cardiovascular and other long term effects indicate a multisystem effect of the drug.
A spontaneous leu-linked mutation (ilvH2015) in Escherichia coli K-12 made the strain resistant to 1 mM valine and l mM glycylvaline (Val-r) and caused the isoleucine and valine biosynthetic enzyme, acetohydroxy acid synthase, to be less sensitive to feedback inhibition by valine than the wild-type enzyme. Transfer of the ilvDAC deletion into a strain carrying ilvH2015 abolished the effect of the marker on the acetohydroxy acid synthase and rendered it as sensitive to valine as the enzyme in the isogenic control strain without the Val-r marker under both repressing and limiting conditions. In contrast, auxotrophy caused by transfer of an ilvC lesion into the Val-r strain did not interfere with the effect of ilvH2015 on valine sensitivity of acetohydroxy acid synthase. In addition, the presence of the Val-r marker produced minor but significant pleiotropic effects on several other isoleucine and valine biosynthetic enzymes but did not cause derepression of the ilv gene cluster. These studies suggest some type of interaction between a product produced by a gene close to leu and the isoleucine and valine biosynthetic enzymes.
Valyl-, isoleucyl-, and leucyl-transfer ribonucleic acid synthetase formation was compared in isogenic strains of Escherichia coli K-12 that differed only in that one strain carried a deletion of three genes of the ilv gene cluster, ilvD, -A, and -C. It was found that: (i) the activities of these synthetases in the deletion strain were less than those in the normal strain during growth in minimal medium supplemented with excess isoleucine, valine, and leucine, and (ii) their stability was reduced in the deletion strain during specific branched-chain amino acid limitations. The results of density-labeling experiments suggest that the in vivo stability of valyl-, isoleucyl-, and leucyl-transfer ribonucleic acid synthetases requires some product missing in the ilvDAC deletion strain.
Blood flow and pressures around a canine femoral arteriovenous fistula, constructed from an autogenous carotid artery, were measured to determine the pressure-flow relationships within the fistula, as well as to determine the presence or absence of retrograde flow in the distal artery and vein. The findings indicate that retrograde arterial flow occurs only when the proximal femoral artery is occluded and, even then, the contribution to fistula flow is small and well below control femoral arterial flow. Retrograde distal venous flow is negligible. Pressure within the fistula is high at the arterial end but is rapidly dissipated across the loop fistula to equal systemic venous pressure on the venous side. Modest distal venous hypertension accompanies this type of fistula. For these reasons, a loop-type, arteriovenous fistula is preferable to other types of fistulas for most clinical surgical indications.
Twenty-four dogs were divided into five groups. Under pentothal sodium anesthesia, those in the control group received no further manipulation; another group underwent laparotomy only; and dogs in the last three groups had induced pancreatitis, intestinal ischemia and duodenal perforation, respectively. An analysis was made of serum and peritoneal lavage fluid in the dog of each group at 30 minute intervals for four and one-half hours. Parameters which were significantly elevated in dogs with pancreatitis compared with other groups included fluid amylase, lactate dehydrogenase, proteolytic activity and intestinal alkaline phosphatase and serum amylase. We judge that these biochemical differences in the lavage fluid, when taken with the physical characteristics of the fluid and the clinical symptoms, can significantly aid the clinician in arriving at the diagnosis of acute pancreatitis.
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