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Biomedical subjects

Y Sakurai

Publications and source records attributed to Y Sakurai.

At least 631 records · Page 35Linked to original sources
PubMed1980

Role of prostaglandin in the antihypertensive mechanism of captopril in low renin hypertension.

1. The role of endogenous prostaglandins in the antihypertensive mechanism of the angiotensin converting enzyme inhibitor, captopril, was investigated. 2. An unequivocal reduction in blood pressure and significant increase in plasma renin activity and urinary prostaglandin E excretion were found after the captopril administration. 3. The changes in blood pressure, plasma renin activity and urinary prostaglandin E excretion induced by captopril were reversed after the inhibition of endogenous prostaglandin synthesis by indomethacin. However, the responses in low renin hypertension were different from those in normal renin hypertension. 4. In low renin hypertensive patients who responded to captopril, the hypotensive effect was abolished after th addition of indomethacin, whereas no marked change in blood pressure was induced by indomethacin in normal renin hypertensive patients. In contrast, plasma renin activity was markedly increased after captopril administration in normal renin hypertension, and no significant change was found in low renin hypertension. 5. Potentiation of the prostaglandin system seems to be a principal factor in the antihypertensive mechanism of captopril in low renin hypertension, and inhibition of the renin-angiotensin system is important in normal renin hypertensives. 6. The increase in renin release after the administration of captopril was inhibited by indomethacin, suggesting that an endogenous prostaglandin system may contribute to the short feedback mechanism of renin release.

Adult↗
PubMed1980

Antitumor efficacies of aclacinomycin A by oral administration.

For the purpose of seeking a possible base for the oral clinical application of an anthracycline antibiotic, aclacinomycin A (ACM), ACM was given orally to the mice bearing Lewis lung carcinoma, colon adenocarcinomas 26 and 38, and compared with the effect of adriamycin (ADM). Oral administration of ACM at 5 or 10 mg/kg for 10 time suppressed the growth of Lewis lung carcinoma. There was no significant difference in survival times of the tumor-bearing mice given ACM orally at various dosages tested. ADM was not effective orally as long as the antitumor effect was examined at the dose levels tested. However, significant increase in the survival time of the mice implanted s.c. with colon adenocarcinoma 26 or 38 was noted for oral administration of ACM at 5-10 mg/kg for 10 times. Ths is, at 10 mg/kg of ACM, T/C% was 187% against colon 26 and 141% against colon 38, respectively. ADM, was not effective against these mouse tumors when given orally. Clinical application of ACM by oral administration, however, will need further studied including preclinical pharmacology, drug formulation and others.

Aclarubicin↗
PubMed1980

Implication of endogenous prostaglandin system in the antihypertensive effect of captopril, SQ 14225, in low renin hypertension.

The role of endogenous prostaglandins in the antihypertensive mechanism of orally active angiotensin I-converting enzyme inhibitor in low renin hypertension was investigated. In the SQ 14225-responders with low renin hypertension, blood pressure was elevated to control level and antihypertensive effect of SQ 14225 was attenuated after the inhibition of endogenous prostaglandin synthesis with indomethacin, while no significant change in blood pressure was found in the SQ 14225-responders with normal renin hypertension. Urinary prostaglandin E excretion was not significantly increased after the SQ 14225 administration but significantly decreased after the administration of indomethacin. There was no significant difference in urinary prostaglandin E excretion between normal renin hypertension and low renin hypertension. These results suggest that SQ 14225 may potentiate extrarenal vasodilating prostaglandin system, probably vascular prostaglandin system, contributing to the antihypertensive mechanism in SQ 14225-responders with low renin hypertension. The augmented renin release following SQ 14225 administration was inhibited by indomethacin, suggesting that endogenous prostaglandin system may contribute to the negative short feedback mechanism of renin release.

Adult↗
PubMed1980

Exaggerated response of renin secretion to captopril (SQ 14225) in renovascular hypertension.

Captopril (SQ 14225), an orally active converting enzyme inhibitor, was administered in a dose of 50 mg to 12 normotensive subjects (Group I), 26 essential hypertensive patients (Group II), and 8 renovascular hypertensive patients (Group III). In Group III, 5 of the 8 patients had control plasma renal activity (PRA) similar to those in Groups I and II patients, but the PRA response to the administration of captopril was greater in 7 of the 8 patients than those in Groups I and II. These 7 patients had either bilateral or unilateral main renal artery stenosis. Captopril caused no increase in PRA in the remaining 1 who had unilateral renal artery stenosis with contralateral renin aplasia. It is concluded that this provocation test is useful as a screening procedure for the diagnosis of renovascular hypertension.

Adolescent↗
PubMed1980

A screening test for renovascular hypertension by means of orally active angiotensin I converting enzyme inhibitor, captopril (SQ 14225).

Orally active converting enzyme inhibitor (Captopril, SQ 14225) was administered in a dose of 50 mg to 12 normotensive subjects (Group I), 26 essential hypertensive patients (Group II) and 8 renovascular hypertensive patients (Group III). In Group III, 5 of 8 patients had control plasma renin activity (PRA) similar to those in Group I and II patients, but the PRA response to the administration of Captopril was greater in 7 of 8 patients than that in Groups I and II. These 7 patients had either bilateral or unilateral main renal artery stenosis. Captopril caused no increase in PRA in the remaining 1 who had unilateral renal artery stenosis with contralateral renal aplasia. It is concluded that this provocation test is useful as a screening procedure for the diagnosis of renovascular hypertension.

Captopril↗
PubMed1980

Growth inhibition of Lewis lung carcinoma by an inorganic dye, Ruthenium Red.

The growth of subcutaneously transplanted Lewis lung carcinoma in BDF1 mice was inhibited by an inorganic dye, Ruthenium Red. The mean volume of the tumors of the mice which were given Ruthenium Red by daily ip injection of 5 mg/kg on days 1 approximately 10 was 28 and 39% of that of the controls at days 18 and 23 after transplantation, respectively. The median survival time (MST) of the treated mice was 27.8 days while that of the control was 23.0 days. The higher MST (32.5 days) was obtained when the dye was given at 2.5 mg/kg for 1 approximately 20 days, although the tumor volume in this group of mice was 51% of that of the control at day 18.

Animals↗
PubMed1980

In vivo potentiation of concanavalin A-bound L1210 vaccine by antimacrophage agents.

Carrageenan potentiated in vivo the primary and secondary responses by concanavalin A (Con A)-bound L1210 murine leukemia vaccine and induced in histocompatible animals enhanced immune resistance to subsequent inoculations of live L1210 cells. This enhancement was critically dependent on the vaccine preparation and the administration timing of carrageenan. Carrageenan potentiated Con A-free vaccine to a much lesser extent if at all, than did Con A-bound vaccine, and it was effective only on the day of or one day after vaccine administration. This enhancement was L1210 specific as evidenced by the lethal growth of P388 leukemia cells in animals inoculated with Con A-bound L1210 vaccine and carrageenan. This is explicable by the increase of spleen but not peritoneal exudate effector cells as measured by suppression of in vitro L1210 cell growth. The following findings suggested that potentiation of Con A-bound vaccine by carrageenan was achieved by affecting suppressor macrophages. Silica and trypan blue, other antimacrophage agents, potentiated Con A-bound vaccine. The enhancement was nullified by the macrophage-stabilizing agent, poly-2-vinylpyridine N-oxide. This hypothesis was further evidenced by the following findings. Phagocytic peritoneal cells induced by Con A-bound vaccine and adhering to the plastic vessel suppressed in vitro spleen cell blastogenesis. Antimacrophage agents abrogated not only production but also activity of these suppressor cells. The combined administration of Con A-bound L1210 vaccine and carrageenan produced an enhanced antitumor immune response and prolonged the life span of tumor-bearing animals marginally but significantly.

Animals↗
PubMed1980

Immunoprophylactic and immunotherapeutic response by concanavalin A-bound tumor vaccine enhanced by chemotherapeutic agents eliminating possible suppressors.

The combined administration of mitomycin C (MMC) on Day 5 and concanavalin A (Con A)-bound L1210 murine leukemia vaccine on Days 1 and 8 induced an enhanced therapeutic response in animals bearing L1210 leukemia greater than that inducible by either of them. The enhancement was dependent on the administration timing of the vaccine, dependent on vaccine-bound Con A, and specific for L1210 leukemia, as evidenced by the fact that no enhancement was induced in P388 leukemic animals. However, the enhancement was dependent on delayed MMC administration, and MMC administered on Day 3 failed to induce the enhancement, indicating that the chemotherapeutic potency of MMC played no major role in the enhancement. These results suggest that the enhancement may be dependent on antileukemia immunity induced by Con A-bound vaccine and may be further potentiated by MMC. A series of experiments comparing immunoprophylactic and immunotherapeutic responses inducible by different chemotherapeutic agents combined with the vaccine suggested that chemotherapeutic agents enhanced the potency of the vaccine by abrogating suppressors associated with vaccine-bound Con A. This hypothesis was supported by the finding that tumor vaccine induced peritoneal cells of tumor-bearing animals were abrogated in their suppressor activity in polyclonal in vitro spleen cell blastogenesis when these animals were further treated with MMC.

Animals↗
PubMed1980

Management of severe hypertension with nifedipine in combination with clonidine or propranolol.

The hypotensive effect of nifedipine was studied in 9 patients with severe hypertension. After oral administration of 20 mg nifedipine mean arterial pressure (MAP) fell, reaching lowest values about 1 h p.a. The antihypertensive effect lasted 7 h. Treatment with nifedipine alone (80 mg/day) lowered MAP significantly on the first day, but it tended to rise again therealter. Addition of clonidine (450 micrograms/day) or propranolol (120 mg/day) enhanced the hypotensive effect. Furosemide (120 mg/day) was ineffective when added to the above described regimen. Without nifedipine the combine drugs failed to keep MAP down. The decrease of MAP observed when giving this combination of drugs was associated with a significant fall in total peripheral resistance and plasma renin activity, but did not alter cardiac output and blood volume. We concluded that nifedipine together with clonidine or propranolol is very effective in the management of severe hypertension.

Adult↗
PubMed1980

[A case of giant aneurysm at the anterior communicating artery treated by direct surgery (author's transl)].

The patient, a 54-year-old male, was suddenly attacked with severe headache and unconsciousness in March 1968. Since then he complained headache and became aware of decreased visual acuity in his right eye. He visited an ophthalmological clinic and was referred to our department of neurosurgery under the suspicion of parasellar tumor. Cerebral angiogram revealed a giant aneurysm of the anterior communicating artery. CT scan revealed a ring shape high density area about 35 mm in diameter and the center of its high density area enhanced by conray infusion. Direct operation was done and succeeded under our prolongation method of the occlusion time of cerebral arteries due to administration of 20% mannitol. Details of our operative method of giant aneurysm at the anterior communicating artery was discussed.

Cerebral Angiography↗
PubMed1980

[Pulmonary metastasis from cerebellar medulloblastoma--report of a case and review of the cases in the literature (author's transl)].

A case of medulloblastoma with pulmonary metastasis was reported. The patient was a 9-year old female who was diagnosed as cerebellar medulloblastoma and treated by total removal of the tumor with adjuvant radiotherapy. The recurrence occurred and the expired 4 months after surgery. The entire clinical course was 2 1/2 years. Autopsy revealed a secondary focus of medulloblastoma in the upper lobe of right lung. No residural tumor was found in the brain. In the literature, 54 cases of extracranial metastasis of medulloblastoma was reported. Only eight of which lead metastatic deposits in the lung. We discussed the possible routes and sites of metastasis in relation to the treatment and prognosis on these cases who showed extracranial metastasis of medulloblastoma.

Cerebellar Neoplasms↗