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Biomedical subjects

M Miyazaki

Publications and source records attributed to M Miyazaki.

At least 955 records · Page 53Linked to original sources

Length-passive tension relationships in cerebral and peripheral arteries isolated from spontaneously hypertensive and normotensive rats.

The length-passive tension relationship was compared in helically-cut strips of the basilar, renal and mesenteric arteries and the aorta isolated from Kyoto Wistar (WKY) rats and stroke-resistant (SHRSR) and stroke-prone spontaneously hypertensive rats (SHRSP). Passive tension developed by the same magnitude of rapid stretch was greater in basilar arteries than in the other arteries and aortae. The length-tension curve shifted toward the tension axis in basilar arteries and aortae isolated from SHRSP as compared with those isolated from WKY, whereas the curves in mesenteric and renal arteries from SHRSP, SHRSR and WKY were not significantly different. It is concluded that the distensibility of various arteries isolated from rats differs, and the cerebral artery becomes less distensible during the persistence of hypertension and the rat become prone to stroke.

Animals↗

Effects of elcatonin on plasma and urine electrolytes in infant beagles.

The effects of elcatonin (ECT) on the renal hemodynamics and electrolyte levels in plasma and urine were investigated in anesthetized infant beagles (3 months old) and adult beagles (9-10 months old). Intravenous injections of 50 MRC U/kg ECT did not alter the systemic blood pressure, renal blood flow, glomerular filtration rate, and urine flow in intact puppies as well as in puppies and adult dogs subjected to extirpation of the thyroid and parathyroid glands (TPTX). One hundred and twenty min after ECT injection, the plasma calcium concentration decreased by 1.06 +/- 0.15 mEq/l in intact puppies and 0.94 +/- 0.10 mEq/l in TPTX puppies, but decreased only by 0.38 +/- 0.22 mEq/l in adult TPTX dogs. The urinary calcium excretion decreased in all the puppies. The plasma phosphorus concentration decreased by 1.02 +/- 0.10 mg/dl, and the phosphorus excretion rate increased 63.6 +/- 26.4% in intact puppies; whereas the plasma phosphorus and phosphorus excretion were not altered in TPTX puppies. Diuresis and natriuresis were not obtained. These data suggest that the acute hypocalcemic effect of ECT is dependent on age and is not associated with its action on kidneys.

Animals↗

Involvement of endogenous prostaglandin I2 in the vascular action of histamine in dogs.

In helical strips of dog mesenteric and gastroepiploic arteries contracted with prostaglandin (PG) F2 alpha, the addition of histamine (10(-6) M) caused a relaxation, which was markedly attenuated by treatment with aspirin, indomethacin or tranylcypromine. Treatment with chlorpheniramine prevented the inhibitory effect of aspirin or tranylcypromine. Combined treatment with chlorpheniramine plus aspirin or tranylcypromine slowed the development of histamine-induced relaxations as did the treatment with chlorpheniramine alone. Relaxations of mesenteric and gastroepiploic arteries induced by histamine were markedly attenuated or abolished by combined treatment with chlorpheniramine and cimetidine. Histamine-induced relaxations of coronary and renal arterial strips were suppressed by cimetidine alone but were unaffected by aspirin. Contractile responses of cerebral arterial strips to histamine were attenuated by chlorpheniramine and potentiated by aspirin. The collagen-induced platelet aggregation was inhibited by treatment with bathing media in which mesenteric arteries were stimulated by histamine; the inhibition was prevented by treatment of the arteries with aspirin. It may be concluded that relaxation of mesenteric and gastroepiploic arteries induced by histamine is mainly associated with the release of prostaglandin I2 from the arterial wall, which results from an activation of histaminergic H1 receptors. Histamine-induced cerebroarterial contractions mediated via H1 receptors appear to be partly counteracted by prostaglandin I2 released.

Animals↗

Plasma motilin levels in patients with abdominal surgery.

Plasma motilin levels were measured by radioimmunoassay both pre- and postoperatively in 37 patients who underwent abdominal surgery. In 8 colorectal cancer patients with tumor removal and in 13 stomach cancer patients with total gastrectomy by Roux-en-Y anastomosis or subtotal gastrectomy of Billroth I anastomosis, the motilin levels decreased before the onset of postoperative peristalsis, and at the time when peristaltic sounds could be detected stethoscopically, the plasma motilin levels had increased by 200% of the preoperative level. Similar motilin levels were maintained until the time of the initial postoperative flatus and/or stool. Thereafter, plasma motilin levels decreased and returned to almost the same levels as the preoperative ones. The postoperative time course of plasma motilin in 10 gallstone patients was very similar to that in the 21 gastrointestinal cancer patients above. In 5 stomach cancer patients with subtotal gastrectomy of Billroth II anastomosis, however, the peak at the time of the initial postoperative peristalsis was not as remarkable as that in the 13 stomach cancer patients.

Adult↗

[Clinical use of acetylspiramycin for primary atypical pneumonia in the field of pediatrics].

Thirty-one patients with primary atypical pneumonia (16 patients diagnosed as Mycoplasma pneumonia) who visited our Department of Pediatrics between March and December, 1981 were treated with 200 mg tablets of acetylspiramycin. Clinical effects were studied, and the results were as follows. 1. Acetylspriramycin, in principle 30 mg/kg/day, was given to 31 patients with primary atypical pneumonia. The effective rate was 87.1%. (As for the patients with Mycoplasma pneumonia, the effective rate was 93.8%). 2. There was 1 ineffective case and it was judged as a case of other viral pneumonia by the results of clinical laboratory tests. 3. The only side effect observed was eruption which occurred on the 6th day of administration in 1 case and disappeared after the change of administration. From the above results, acetylspiramycin is thought to be an effective antibiotic on primary atypical pneumonia.

Adolescent↗