Search PubMed⌕ Search

Biomedical subjects

M Miyamoto

Publications and source records attributed to M Miyamoto.

At least 577 records · Page 32Linked to original sources
PubMed1981

Effects of captopril on urinary excretion of prostaglandins and electrolytes in spontaneously hypertensive rats.

Captopril was administered to spontaneously hypertensive rats (SHR) and the acute and long-term effects on the urinary excretion of Na, K, prostaglandin (PG)E2 and PGF2 alpha were studied. Captopril (30 mg and 100 mg/kg p.o.) increased urine volume, urinary Na and K excretion on the 1st and 2nd days of its administration. The urinary K/Na ratio was decreased in the captopril-treated groups on the 1st to 3rd day. Urinary PGE2 excretion in the captopril 100 mg/kg group was significantly increased compared to that in the control group (210.6 +/- 31.4 vs. control 123.2 +/- 8.4 ng/day) on the 1st day of captopril administration. A slight but significant increase in urinary PGF2 alpha excretion was also seen in the captopril 100 mg/kg group (105.2 +/- 9.8 vs. control 75.8 +/- 2.1 ng/day). But PG excretion declined during prolonged treatment and these were no significant difference between the control and captopril-treated groups on the 3rd and 6th week. These data suggest that captopril increases renal PG only as an acute phase and that the increase of PG at least partly accounts for natriuretic affects of the agent.

Animals↗
PubMed1981

Malignant duodenocolic fistula--a case report.

A 63 year-old woman with a malignant duodenocolic fistula of colonic origin was so diagnosed following radiological examination. She had symptoms of feculant vomitus, persistent diarrhea and emaciation. Following preoperative treatment of the nutritional and electrolyte disorders with intravenous hyperalimentation, a one-staged right hemicolectomy and pancreatoduodenectomy was performed successfully. We emphasized that an en-bloc removal of all the possibly involved structures is the most successful procedure for malignant duodenocolic fistula of colonic origin.

Adenocarcinoma↗
PubMed1981

Intracranial germ cell tumor indicating a high level of alpha-fetoprotein (AFP).

An autopsy case of intracranial and extrapineal tumor is reported. The tumor, detected 2 years and 4 months before death, was an ectopic pinealoma (germ cell tumor) and showed elevated serum alpha-fetoprotein (AFP) of 48,000 ng/ml. Histologically, intra- and extracellular PAS-positive hyaline globules were observed in the tumor. The tumor tissues of the paraffin sections revealed a bright positive fluorescence for AFP with indirect immunofluorescence method. Besides, there were generalized metastases in this case.

Adult↗
PubMed1981

Plasma aldosterone response to angiotensin II in sodium-restricted elderly subjects with essential hypertension.

The plasma aldosterone (PA) response to sodium restriction (25 mEq daily for 4 days) and to graded infusions of angiotensin II (AII, 2, 4 and 8 ng/kg/min each for 30 min) during a low-sodium intake were studied in 15 elderly subjects with mild essential hypertension versus 10 elderly normotensive subjects. The PA response to sodium restriction relative to changes in plasma renin activity (PRA) was estimated by the ratio of PA increment to PRA increment after sodium restriction (delta PA/delta PRA). THe PA response to graded AII infusions was determined by the increment of PA above the basal level after each dose of AII. In 10 of the 15 elderly hypertensive subjects whose PRAs responded normally to sodium restriction, the delta PA/delta PRA ratios and PA increments during the graded AII infusions were similar to those in the elderly normotensive subjects. However, in the remaining 5 elderly hypertensive subjects whose PRAs responded subnormally to sodium restriction, the delta PA/delta PRA ratios were high and the PA increments greater during the graded AII infusions. THe increments of mean blood pressure during the graded AII infusions were similar in the foregoing 10 of 15 hypertensive subjects, and significantly greater during the AII infusion rates of 4 and 8 ng/kg/min in the remaining 5 hypertensive subjects when compared with those in the normotensive subjects. Apparently some subjects with essential hypertension, whose PRAs response subnormally to sodium restriction, have an abnormally enhanced adrenal responsiveness to AII under the conditions of low-sodium intake.

Aged↗
PubMed1981

Study of HLA antigens among Japanese schizophrenics.

HLA antigens were typed among 136 Japanese schizophrenics. Increased frequencies were seen in A9 (Aw24), A10 (A26) and Bw54, and decreased frequency in B40 antigens when compared to 187 Japanese controls. It is suggested that there may be an association between A9 (Aw24) and schizophrenia with a chronic-progressive course and also an association between A10 (A26) and hebephrenia.

Adult↗
PubMed1981

Antihypertensive activity of bucumolol, a beta-adrenergic blocking agent, in spontaneously hypertensive rats.

Effects of bucumolol, a beta-adrenergic blocking agent, on blood pressure and the renin angiotensin system were studied in spontaneously hypertensive rats (SHR). The results were compared with those of propranolol at an equipotent dose in beta-adrenergic blocking activity. Bucumolol lowered blood pressure and decreased plasma renin concentration (PRC) in both acute and long-term experiments. There was a significant correlation between percent changes in blood pressure and PRC following a single administration of bucumolol. Decrease in PRC persisted for the 6-week observation period despite the sustained reduction in blood pressure. On the other hand, propranolol did not lower blood pressure in acute experiment while it decreased renin release. These results suggest that inhibition of renin release is involved in the antihypertensive action of bucumolol.

Adrenergic beta-Antagonists↗
PubMed1981

Long-term effects of captopril on cellular sodium content and mechanical properties of aortic smooth muscle from spontaneously hypertensive rats.

The long-term effects of captopril on passive Na permeability and Na content in aortic smooth muscles of spontaneously hypertensive rats (SHR) were examined in relation to the mechanical properties of the muscles. Captopril or hydralazine when administered for 6 weeks exhibited antihypertensive action throughout the period. Cellular Na in both freshly excised aortas and incubated aortas from SHR leaked out more rapidly in cold Li-solution than those from normotensive Wistar-Kyoto rats, suggesting increased permeability in SHR aortas. Long-term treatment with captopril decreased the "permeability" of the vascular membrane of SHR, whereas hydralazine failed to decrease it. Incubation of the aortas in K+-free Tyrode's solution produced a slowly developing contraction. The rate of rise of this contraction was faster in SHR aorta that in Wistar-Kyoto aorta. In aortas from captopril-treated SHR, the rate of rise in the contraction was suppressed. The contractile response to K+-free medium was related to the passive permeability to Na and thereby to the increment of cellular Na. It is suggested that, after prolonged administration, captopril alters the abnormal permeability to Na of the vascular smooth muscle membrane in SHR and that the alteration contributes to the antihypertensive effect of the agent.

Animals↗
PubMed1980

The catabolism of alloantibody IgG2a in normal and homograft tolerant rats.

Alloantibody was raised in PVG/c rats against DA rats. The catabolism of alloantibody in normal PVG/c rats and PVG/c rats tolerant to DA rats was followed after intravenous injection. A haemagglutination assay was used to detect alloantibody activity. The half-life time of alloantibody IgG2a in the normal PVG/c rats was 10 days. On the other hand, in the PVG/c rats tolerant to DA rats, the half-life of alloantibody IgG2a varied. The rats could be divided into three groups. Group A: alloantibody IgG2a was eliminated from the circulation very rapidly. Group B: alloantibody IgG2a disappeared from the circulation relatively rapidly and was maintained at a low level in the plasma but then increased to a high titre. This peculiar pattern of Group B seems to be due to the endogenous production of alloantibody. In this case abrogation of tolerance took place. Group C: the pattern of elimination of this group was almost identical to that of normal rats. The biological significance of the plasma decay of alloantibody IgG2a in the normal and homograft tolerant rats has been considered. It is concluded from the present results that alloantibody might be important in some cases for the maintenance of homograft tolerance.

Animals↗
PubMed1980

Male skin isografts can induce unresponsiveness in female rats.

Nonsensitized (DA x PVG/c) F1 hybrid female rats regularly accepted male skin isografts. However, almost all F1 females sensitized with male F1 bone marrow cells rejected male skin isografts. Spleen cells taken from sensitized F1 females, either before or after the rejection of male skin isografts, conferred resistance against graft-versus-host (GVH) reactions produced in F1 females by parental PVG/c lymph node cells, but only when the cell donors were male. Repeated injection with bone marrow cells from F1 males failed to cause rejection of established male skin grafts by F1 females. Additional male skin grafts transferred after bone marrow cell injection were also retained. However, if established male skin isografts had been deliberately removed from F1 females before injection of male bone marrow cells, subsequently placed male skin grafts were rejected. Neither spleen cells collected from F1 females bearing established male skin isografts after repeated injection with male bone marrow cells, nor spleen cells obtained from F1 females that had received four consecutive male skin isografts were observed to confer resistance against GVH reactions produced by male PVG/c lymph node cells in F1 female recipients. Splenectomy of prospective F1 female recipients did not confer on them the capacity to reject male skin isografts. These results imply that the placement of a male skin isograft interfered with subsequent attempts to stimulate F1 hybrid females to reject male grafts and to resist GVH reactions produced by lymphocytes from PVG/c males.

Animals↗