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Biomedical subjects

H Hashimoto

Publications and source records attributed to H Hashimoto.

At least 1,315 records · Page 73Linked to original sources
PubMed1981

Regular segregation of composite plasmid Rms201.

Copy number mutants Rms201ts15 and Rms201ts16 were isolated at 30 degrees C from a temperature-sensitive replication mutant (Rms201ts14) of the conjugative plasmid Rms201. The numbers of plasmids per chromosome of ML1410(Rms201ts14), ML1410(Rms201ts15), and ML1410(Rms201ts16) grown at 30 degrees C were 2.2, 7.4, and 20, respectively. The synthesis of covalently closed circular plasmid deoxyribonucleic acid stopped in Rms201ts14, Rms201ts15, and Rms201ts16 immediately after a "shift-up" in temperature (42 degrees C). At 42 degrees C, antibiotic-sensitive derivatives appeared after a certain lag time: the lag times of ML1410(Rms201ts14), ML1410(Rms201ts15), and ML1410(Rms201ts16) were 2.5, 5, and 6.8 generations, respectively. After these times, plasmid-positive cells in the populations decreased at a rate of about 50% per generation in all of the mutants. From these results we conclude that plasmid segregation (partition) of Rms201 occurs by regular segregation (partition).

Ampicillin↗
PubMed1981

Effects of a single administration of captopril on hemodynamics and serum angiotensin converting enzyme activity, plasma renin activity and plasma aldosterone concentration in hypertensive patients.

Hemodynamic responses and behaviors of the renin-angiotensin-aldosterone system to a single administration of captopril (50 mg) were studied in 16 hypertensive patients (essential hypertension, n = 10; renovascular hypertension, n = 3; primary aldosteronism, n = 2; Cushing's syndrome, n = 1). In 10 essential hypertensive patients, the immediate blood pressure reduction caused by decreased total peripheral resistance after the administration of captopril was observed without changes of cardiac output and heart rate. Serum angiotensin converting enzyme activity and plasma aldosterone concentration significantly decreased, whereas plasma renin activity significantly elevated 2 hours after the administration of captopril. The close relationship between the pretreatment value of plasma renin activity and the maximum decrease in mean blood pressure in 16 hypertensive patients suggests that the depressor response to a single administration of captopril could evaluate the degree of angiotensin II dependency in the maintenance of high blood pressure in various types of hypertension.

Adult↗
PubMed1981

Effect of calcium antagonists on the electrical alternans of the ST segment during acute coronary occlusion in dogs.

Effects of antagonists on the ST alternans during acute coronary occlusion were examined in dogs. The intravenous administration of verapamil at doses of 0.1 mg/Kg and 0.2 mg/Kg prominently attenuated the degree of alternans. Diltiazem at dose of 0.2 mg/Kg also attenuated the degree of alternans. Dipyridamole at dose of 0.5 mg/Kg did not significantly attenuate the degree of alternans. Verapamil significantly inhibited the ST-segment elevation. After verapamil, ST alternans did not occur even after a longer period of occlusion when changes in QRS complex and the ST-segment elevation were remarkable. It is possible that verapamil inhibits ST alternans by both the protecting effect against ischemic injury and a direct effect on the electrical activity of the myocardial cell membrane.

Acute Disease↗
PubMed1981

Effects of sulfinpyrazone, aspirin and propranolol on the isoproterenol-induced myocardial necrosis.

Prophylactic effects of sulfinpyrazone (100 mg/Kg), aspirin (5 mg/Kg, 50 mg/Kg), and propranolol (2 mg/Kg, 10 mg/Kg) on myocardial necrosis and hypertrophy induced by isoproterenol were examined. Drugs were administered to rats daily by gavage for a period of 2 weeks and after that isoproterenol (40 mg/Kg) was injected subcutaneously. The control group received gavage of water and isoproterenol injection. The "no infarct" group received gavage of water and saline injection. Premedication of sulfinpyrazone and propranolol significantly preserved myocardial CK activity and decreased cardiac hypertrophy compared with control group (24 hours after isoproterenol injection) while aspirin did not have such effects. Myocardial cyclic AMP concentration significantly increased 30 min after isoproterenol injection in control and all the premedicated rats compared with the "no infarct" rats. The increment of cyclic AMP was not suppressed by sulfinpyrazone and propranolol during this period. Plasma levels of prostaglandins were significantly suppressed by the administration of sulfinpyrazone and 50 mg/Kg of aspirin, and were not suppressed by 5 mg/Kg of aspirin. It was concluded that premedication of sulfinpyrazone and propranolol reduce cardiac necrosis and hypertrophy induced by isoproterenol, but aspirin did not have such cardioprotective effects.

Animals↗
PubMed1981

Virantmycin, a new antiviral antibiotic produced by a strain of Streptomyces.

Virantmycin, a novel chlorine-containing antiviral antibiotic, has been isolated from Streptomyces nitrosporeus No. AM-2722. The active substance in culture broth is isolated as colorless needles by solvent extraction followed by high performance liquid chromatography on silicic acid. The molecular formula is C19H26NO3Cl (molecular weight 351) from the elemental analysis and mass spectrum. The antibiotic possesses antifungal activity and potent inhibitory activity against various RNA and DNA viruses.

Anti-Bacterial Agents↗
PubMed1981

Antihypertensive and general pharmacological properties of budralazine.

Antihypertensive and general pharmacological properties of 1-[2-(1,3-dimethyl-2-butenylidene)hydrazino]phthalazine (budralazine) were studied in comparison with those of hydralazine. Single oral administration of budralazine (4--15 mg/kg) to DOCA/saline hypertensive rats resulted in a dose-related and sustained antihypertensive effect which was 2--3 times less potent than that of hydralazine. However, there were no remarkable differences between both drugs in the hypotensive magnitude after the 4-week treatment of spontaneously hypertensive rats (SHR) with their higher doses. After single oral administration, budralazine was about 8 times less potent than hydralazine in increasing plasma renin activity in normotensive rats. At effective antihypertensive doses, budralazine inhibited spontaneous motor activity (mice), gastrointestinal propulsion (mice), gastric emptying rate (rats), gastric secretion (rats), urine output and urinary electrolyte excretion (rats) as well as carrageenan-induced paw edema formation (rats), which were essentially less potent than those produced by hydralazine. Budralazine at 6 mg/kg i.v. exhibited a slowing of neocortical EEG (cats) and a slight increase in spinal monosynaptic potentials (cats) and inhibited gastrointestinal motility (dogs). The same dose of hydralazine produced an increase in occurrence of the neocortical fast waves, an inhibition of the monosynaptic potentials and the carotid sinus reflex (dogs) and a stimulation of intestinal motility followed by prolonged and marked reduction. Budralazine (10(-5) g/ml) slightly potentiated contractile response of isolated guinea-pig vas deferens to noradrenaline, whereas hydralazine (10(-4) g/ml) inhibited the response. Budralazine (10(-5) g/ml), like hydralazine (10(-4) g/ml), produced a nonspecific antagonism against the contractile response of isolated guinea-pig ileum to various spasmogens, and both drugs (10(-4) g/ml) reduced either spontaneous motility or oxytocin-induced motility in isolated rat uterus.

Animals↗