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Biomedical subjects

A Ito

Publications and source records attributed to A Ito.

At least 1,027 records · Page 57Linked to original sources

Theta-toxin of Clostridium perfringens. I. Purification and some properties.

Theta-Toxin, an oxygen-labile hemolysin produced by Clostridium perfringens, was purified 3300 fold from culture filtrate by successive chromatography on DEAE-Sephadex A-50 and Sephadex G-150. The purified toxin gave two distinct bands in disc electrophoresis, while the same material, after mild reduction with dithiothreitol, yielded a single band, indicating that the purified theta-toxin contained, as well as a reduced, active form, an oxidized, inactive form of toxin. These two forms of the toxin had a similar, if not identical molecular size. The purified preparation gave a single band in a sodium dodecyl sulfate polyacrylamide gel electrophoresis and formed a single precipitin line with National Standard gas gangrene (C. perfringens) antitoxin. By sodium dodecyl sulfate polyacrylamide gel electrophoresis, the molecular weight of theta-toxin was estimated to be 51 000, the value being in exact accordance with that obtained by amino acid analysis. The amino acid composition of theta-toxin was very close to that of cereolysin, an oxygen-labile hemolysin produced by Bacillus cereus. The amino-terminal residue of theta-toxin was lysine as determined by the Dansyl method.

Amino Acid Sequence↗

PZ-peptidase activity in human uterine cervix in pregnancy at term.

PZ-peptidase (EC 3.4.--) was detected in human uterine cervix distributed in the soluble fraction after 100 000 x g centrifugation. Optimum pH for PZ-peptidase was observed to be pH 7.2--7.4, except for two of the preparations examined. PZ-peptidase activity was found to significantly increase in pregnancy at term as compared with that in a control group.

Cervix Uteri↗

Subfractionation of rat liver microsomes by immunoprecipitation and immunoadsorption methods.

Rabbit antisera were prepared against cytochrome b5 and NADPH-cytochrome c reductase [EC 1.6.2.4] purified from rat liver microsomes, and utilized in examining the distribution of these and other membrane-bound enzymes among the vesicles of rat liver microsomal preparations by immunoprecipitation and immunoadsorption methods. Smooth microsomes with an average vesicular size of 200 nm (diameter) and sonicated smooth microsomes with an average diameter of 40-60 nm were used in subfractionation experiments. Immunoprecipitation of microsomal vesicles with anti-cytochrome b5 immunoglobulin failed to show any separation of the microsomes into fractions having different enzyme compositions. Cytochrome b5 was apparently distributed among all vesicles even when sonicated microsomes were used. When the antibody against NADPH-cytochrome c reductase was used, however, immunoadsorption of microsomes on Sepharose-bound antibody produced some separation of NADPH-cytochrome c reductase and cytochrome P-450 from NADH-cytochrome b5 reductase and cytochrome b5. The separation was more pronounced when sonicated microsomes were used. These results indicate microheterogeneity of the microsomal membrane, and suggest the clustering of NADPH-cytochrome c reductase and cytochrome P-450 molecules in the membrane.

Absorption↗

Correction of water content and solute concentration in blood during hemoconcentration.

Eleven, healthy male students were subjected to an exhaustive bicyle ergometer exercise. Many parameters of hemoconcentration were examined in blood and urine samples which were collected before and after exercise. In an exercise lasting approximately 10 min, it was found that serum total protein (STP) would be a suitable parameter that could be used to calculate water content and actual decrease in water volume in blood due to exercise. Further, it is described how STP values before and during hemoconcentration can be used to eliminate the effect of plasma water loss from the determined values of various solute levels in blood.

Adult↗

Hemoconcentration during isotonic handgrip exercise.

Three healthy males performed an intense isotonic handgrip ergometer exercise to exhaustion (approximately 10 min). Serum water, serum total protein (STP), and hematocrit were determined in the venous blood taken from the brachial veins in both exercised and nonexercised arms before exercise and 10 s, 1, 2, and 3 min after the termination of exercise. Although no sweat was observed, hemoconcentration occurred in both arms. The peak degree of water loss in the nonexercised arm, however, was delayed and lower than that in the exercised arm. Further, three healthy males were exposed to a sauna (76 degrees C) for 20 min to test the effect of sweating on hemoconcentration in the absence of physical movement. Venous blood was withdrawn from the forearm vein before the sauna, after 5 min in the sauna, and at 3 and 30 min during sitting recovery period. No hemoconcentration was observed during the course of the experiment.

Adult↗

[Effect of nitroglycerin on peripheral venous pressure at rest and during exercise in patients with heart diseases (author's transl)].

1) In "left-sided" cardiac diseases, the effects of nitroglycerin on arterial pressure and heart rate were noted to be modest and disappeared within 15 minutes whereas the effect upon venous pressure, measured on the median cubital vein, lasted for approximately 30 minutes. 2) At 30 minutes after a dose of nitroglycerin there occured a significant depression of venous pressure elevation on exertion in patients with such "left-sided" cardiac diseases as ischemic heart disease, arteriosclerotic heart disease and hypertensive cardiovascular disorder. In patients with mitral insufficiency and aortic stenosis, on the other hand, the exertional venous pressure elevation was significantly suppressed 7 minutes after nitroglycerin although the suppression did not longer exist 30 minutes after administration. 3) The arterial pressure, heart rate, resting venous pressure and venous pressure elevation on exertion were virtually not affected by the administration of nitroglycerin in "right- or both-sided" cardiac disorders. 4) There was no significant change in cardiac output 30 minutes after a sublingual dose of nitroglycerin. The data obtained seem to stress importance of the effect of dilating capacitance vessels in the mechanism of antianginal action of nitroglycerin.

Adult↗