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S Yoshitake

Publications and source records attributed to S Yoshitake.

93 records · Page 6Linked to original sources

Changes in intramucosal pH and gut blood flow during whole body heating in a porcine model.

Heat stroke is a syndrome which reduces systemic vascular resistance and cardiac collapse. The gut plays an important role in shock. In hyperthermia, many of the same symptoms as heat stroke may be present, including inhibition of splanchnic vasoconstriction and endotoxemia. Furthermore, both conditions result in shock, in which the gut plays an important role. Detection of insufficient oxygenation of gut tissue, which sustains an earlier and more severe hypoxia, can warn of impending shock and can be performed by monitoring intramucosal pH (pHim). This index is very sensitive to tissue hypoxia and ischemia. In the present study both pHim, using tonometry, and gut blood flow during whole body heating (WBH) in pigs were measured. WBH was achieved by circulating warm water through a vinyl sheet covering the animal. Central venous pressure was maintained by fluid infusion. Body temperature was measured using a thermometer probe inserted into the right jugular vein. Mean arterial pressure, cardiac output and gut blood flow were also measured. pHim was evaluated using a tonometer placed into the midileum lumen. During WBH, cardiac index and mean arterial pressure increased, however systemic vascular resistance decreased. Gut blood flow was either maintained at the normal rate or increased. Intraarterial pH did not change significantly, however pHim significantly decreased from 7.30 at the beginning of WBH to approximately 7.05 after the body temperature reached 42.5 degrees C. These findings suggest that there was reduced oxygen delivery to the tips of the small intestinal villi during regional ischemia following WBH. In conclusion, insufficient tissue oxygen delivery as detected by a reduction in inramucosal pH is an important index in whole body heating.

Animals↗

Binding of biotinylated thrombin receptor peptide to cloned human thrombin receptor overexpressed in baby hamster kidney cells.

Baby hamster kidney (BHK) cells transfected with an expression vector for the human thrombin receptor, and then treated with basic fibroblast growth factor, were found to express specific and saturable binding sites for biotinylated thrombin receptor peptide (SFLLRNPNDKYEPF). Analysis of the binding to live BHK cells yielded an equilibrium dissociation constant (Kd) of 3.0 +/- 0.3 mu mol/l and a maximal binding capacity (Bmax) of 31.0 +/- 0.5 nmol/mg of protein. In competitive binding experiments, the thrombin receptor agonist peptide (SFLLRN), which is a strong inducer of human platelet aggregation, was the most potent competitor. In contrast, position 1 to 2 inverted peptides such as FSLLRNPNDKYEPF and FSLLRNP, which fail to induce for the platelet aggregation, were less potent. This simple and convenient binding assay system using the biotinylated thrombin receptor peptide as a labeled ligand and the cloned thrombin receptor overexpressed in BHK cells may be useful for exploring specific antagonists of the receptor.

Amino Acid Sequence↗