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Biomedical subjects

M Nakabayashi

Publications and source records attributed to M Nakabayashi.

At least 91 records · Page 5Linked to original sources
PubMed1974

Physicochemical and biological properties of human and canine plasmins.

Three kinds of plasmin were found to be generated when plasminogen or [(125)I]plasminogen was incubated at 32 degrees C for longer than 20 min in urokinase and 50% glycerol. Each plasmin was then separated by G-200 or G-75 Sephadex filtration, and its physicochemical properties were determined. The molecular weights of the three plasmins as determined by G-200 Sephadex filtration were 125,000+/-5,000(SD), 63,000+/-2,000(SD), and 31,500+/-1,000(SD), and those by sodium dodecyl sulfate(SDS)-polyacrylamide electrophoresis were 130,000+/-5,000(SD), 64,000+/-3,000(SD), and 32,000+/-1,500(SD). It was also found that during the incubation of the smallest plasmin in SDS and beta-mercaptoethanol it was further split into two smaller pieces of about 16,000 mol wt and that polymer proteins of 95,000+/-2,000(SD) and 48,000+/-1,500(SD) mol wt were formed. Despite these differences in the molecular size of the three plasmins, the specific activity of each plasmin was closely similar and in case of human plasmins averaged 29+/-0.9(SD) CTA units/mg plasmin and in case of canine plasmins 8.5+/-0.54(SD) CTA units/mg plasmin. Then, using human plasmin of the smallest size (mol wt 31,500), the total plasma antiplasmin capacity was determined in 20 normal human plasma, which averaged 7.8+/-2(SD) CTA units of plasmin per milliliter plasma. Studies were next made of the affinity of human [(125)I]-plasmin of the smallest size with albumin, gamma globulin, alpha(2)-macroglobulin, alpha(1)-antitrypsin, fibrinogen, and fibrin. The results were 0%, 0%, 14.6+/-0.5(SD)%, 17.6+/-0.6(SD)%, 21+/-0.5(SD)%, and 20.5+/-0.6(SD)%, respectively, of [(125)I]plasmin available and were unaltered when the amount of [(125)I]plasmin was increased to twice and four times the original amount. Finally, the plasma disappearance half-life of canine [(125)I]plasmin of the smallest size was studied in five healthy dogs, which averaged 14.2+/-0.63(SD) h. These results support the concept that the combination between plasmin and plasmin inhibitors is reversible and indicate that fibrinogen and fibrin have greater affinities than alpha(2)-macroglobulin or alpha(1)-antitrypsin.

Albumins↗
PubMed1972

Effects of heparin and epsilon-aminocaproic acid in dogs on plasmin-125-I generation in response to urokinase injections and venous injury.

The isotopic method described previously for quantification of plasmin- (125)I by disc gel electrophoresis was modified by inclusion of euglobulin precipitation to expand its applicability to plasmas containing low radioactivity of plasmin- (125)I and plasminogen- (125)I. It was found that the euglobulin precipitation method precipitates 72.4+/-2.1 (sd)% of both plasmin- (125)I and plasminogen- (125)I. Using this method and plasminogen- (125)I as a tracer, studies were first made of the effects of heparin and epsilon-aminocaproic acid in dogs on plasmin- (125)I generation in responese to a single injection of urokinase and to venous injury; second, of the effects of venous occlusion and thrombosis on plasmin- (125)I generation; and third, in vitro studies of plasminogen- (125)I affinity to fibrin and its activation in blood clots. The venous injury was produced by the damage of venous endothelium by an injection of 90% phenol and the thrombosis by a thrombin injection into an occluded vein. Heparin and epsilon-aminocaproic acid under the present experimental conditions inhibited about 78 and 100%, respectively of plasmin- (125)I generation by the urokinase injection. Similar inhibitory effects of heparin and epsilon-aminocaproic acid were observed on plasmin- (125)I generation in response to venous injury. The venous occlusion caused a small degree of plasmin- (125)I generation, but thrombin thrombosis did not seem to stimulate the generation of plasmin- (125)I. The in vitro studies showed that plasminogen- (125)I does not have a specific affinity to fibrin and is incorporated into blood clots in approximately equal concentrations as those in serum during clotting processes, and that blood clots per se do not stimulate plasmin- (125)I generation. These results suggest that injured veins release considerable amounts of vascular plasminogen activators into circulation and that these play an important role in thrombus dissolution in vivo.

Aminocaproates↗