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Biomedical subjects

R Hashimoto

Publications and source records attributed to R Hashimoto.

At least 145 records · Page 8Linked to original sources
PubMed1987

The depressor effect of secretin administered either centrally or peripherally in conscious rats.

The role of secretin in systemic blood pressure was examined in conscious rats. Either i.c.v. (0.5 or 1.0 micrograms/2 microliter 0.9% saline) or i.v. (1.0 or 2.0 micrograms/10 or 25 microliter saline) administration of secretin in conscious rats resulted in a significant fall in blood pressure. In consideration of previous findings that many other peptides such as substance P, enkephalin, bradykinin, neurotensin and vasoactive intestinal polypeptide cause pressor effects when administered centrally, but produce depressor responses after peripheral administration, the hypotension induced as both central and peripheral effects of secretin is unique and significant.

Animals↗
PubMed1987

Total biopterin levels of plasma in patients with depression.

The total biopterin levels of plasma in 12 patients with depression were measured. They were elevated significantly as compared with those in normal controls. The plasma biopterin levels in 6 of 12 patients were measured both in the depressive and in the remissive phases. In the depressive phase the total biopterin levels were increased, whereas in the remission phase they did not differ from those in normal controls. Antidepressants did not affect the plasma biopterin levels. We speculate that the elevation of the plasma biopterin levels in patients with depression was related to the depressive state itself.

Adult↗
PubMed1987

Roles of catecholamine at the preoptic region in the regulation of cyclic ovulation and gonadotropin.

Experiments were designed to see how a transplantation of newborn norepinephrine (NE) neurons from A-6 groups or dopamine (DA) neurons from A-10 groups in the third ventricle at the level of the preoptic region affected the vaginal oestrous cycle and gonadotropin secretion in the female rat. Sixty-two rats that had tissues in contact with the preoptic region were evaluated as having surviving transplants by histological examination after sacrifice. The rats that had surviving NE-neuron transplants frequently showed prolongation of oestrus during the 70-day study period, indicating that ovulation was severely impaired in these rats. However, after ovariectomy, they showed a pulsatile secretion of LH with a remarkably large amplitude. The DA-neuron transplants sustained the oestrous cycle unchanged, but increased blood levels of FSH prior to the ovulatory secretion of gonadotropin. Pulsatile LH secretion was not affected. Sham and cerebellum control rats did not show any significant changes in the oestrous cycle. The results suggest that the NE-neuron transplants at the preoptic region somehow inhibit gonadotropin secretion in intact rats, whereas they facilitate it in ovariectomized rats. The DA-neuron transplants appear to exert facilitatory effects on FSH secretion in intact rats.

Animals↗
PubMed1986

Inhibition of gonadotropin secretion induced by cholecystokinin implants in the medial preoptic area by the dopamine receptor blocker, pimozide, in the rat.

We have shown that the implantation of cholecystokinin octapeptide sulfated form (CCK-8-S) or dopamine (DA) in the medial preoptic area (MPO) in ovariectomized estrogen-primed rats induced an enhancement of the afternoon rise in LH secretion. The present study was done to examine the possible functional interaction of both substances in the brain. Two groups of ovariectomized estradiol (5 micrograms, s.c.)-primed rats were administered intraperitoneally either pimozide (1 mg/kg BW; pimozide-treated group) or 0.1 M tartaric acid as the control solution (pimozide-untreated group). CCK-8-S or DA was implanted in the MPO through chronically implanted guide cannulae and the effects on serum LH and FSH concentrations were compared between both groups. An empty cannula was used as the control. Implantation of either CCK-8-S or DA in the pimozide-untreated group induced marked enhancements of afternoon rises in LH and FSH levels, which normally occurred, but with a lesser magnitude in the animals with the empty cannula. In the pimozide-treated group, however, neither CCK-8-S nor DA induced changes in the LH and FSH levels. It was evident that both effects of CCK-8-S and DA on LH and FSH secretion were blocked by pretreatment with the DA receptor blocker. These data indicate that DA receptors are required to be intact when CCK-8-S implants manifest their action in stimulating gonadotropin secretion.

Animals↗
PubMed1986

[Congenital subclavian steal syndrome: a case of right aortic arch with atretic aberrant left subclavian artery].

Surgical experience of a rare case of congenital subclavian steal syndrome is reported. A 53 year old man was admitted to our hospital complaining of black out attack and headache. Non invasive and angiographic studies revealed the subclavian steal associated with right aortic arch and atretic aberrant left subclavian artery. Through the supraclavicular incision, the direct anastomosis of the left common carotid and subclavian artery was performed. Postoperative angiograms showed a perfect reconstruction of the left subclavian artery and the disappearance of the subclavian steal and about on third amount of the complaints are still remained. Concerning a review of the literatures, several problems are discussed.

Aorta, Thoracic↗
PubMed1984

Congenital aortic regurgitation in a child with a tricuspid non-stenotic aortic valve.

After follow up for seven years a 10 year old boy with congenital aortic regurgitation was found to have a tricuspid non-stenotic aortic valve at operation. The right coronary cusp was dysplastic, thickened, and contracted; the gap between its free margin and aortic wall was bridged with two fibrous bands; and the left coronary and non-coronary cusps were almost normal. The aortic valve was replaced with a prosthesis (St Jude Medical No 23), and the postoperative course was uneventful.

Aortic Valve↗
PubMed1983

The stimulatory effect of cholecystokinin implanted in the medial preoptic area on luteinizing hormone secretion in the ovariectomized estrogen-primed rat.

The effect of implantation of cholecystokinin(CCK)-8 into the medial preoptic area (MPO) through the chronically implanted guide cannula on the release of LH was examined in the ovariectomized estradiol-primed rat. An inner cannula with CCK-8 at the tip, as well as an empty inner cannula as the control, was implanted into the MPO at 12.00 h. Blood samples were obtained at 11.00, 12.00, 16.00, 18.00 and 20.00 h, and serum concentration of LH was measured by RIA. There was no significant fluctuation over time in the mean serum LH values for each sampling time in the group of animals implanted with empty cannulae in the MPO. In the group of animals implanted with CCK-8 into the MPO, the fluctuation of the mean LH values over time was significant, with a marked and significant elevation of LH values peaking at 16.00 h. It was strongly suggested that CCK-8 was capable of stimulating LH-RH release, acting at the MPO.

Animals↗