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Biomedical subjects

J Kurihara

Publications and source records attributed to J Kurihara.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effect of flunarizine on the attenuation of baroreflex by transient cerebral ischemia.

Baroreflex sensitivity assessed by phenylephrine-induced reflex bradycardia was markedly decreased by 5- an 10-min global cerebral ischemia in anesthetized dogs. Flunarizine, 0.1 and 1 mg/kg i.v., administered 5 min prior to 5-min ischemia, completely inhibited the decrease in baroreflex sensitivity while such a protective effect of the latter dose was incomplete against 10-min ischemia. In contrast, papaverine, 0.5 mg/kg per min i.v., infused for 5 min prior to 5-min ischemia, failed to protect the decrease in baroreflex sensitivity. Flunarizine may possess a certain direct cerebroprotective effect in addition to its cerebrocirculatory effect.

Animals↗
PubMed1989

Enhanced adrenergic response of the cerebral vasculature in alloxan-induced diabetic rats.

The influence of alloxan-induced diabetes on the adrenergic constriction of the rat cerebral vasculature was investigated in the in situ perfused brain preparation. The preparation was perfused with an artificial medium at a constant flow rate and the change in perfusion pressure was measured. Norepinephrine (NE) and serotonin produced a dose-dependent increase in the perfusion pressure, but only the effect of NE was significantly enhanced in the diabetic rats. Such an enhancement of NE-induced vasoconstriction was not observed in the perfused hindquarter preparations from the diabetic rats. Propranolol (1 microM) potentiated the cerebrovascular constriction by NE and abolished the difference between diabetic and control rats at low doses of NE. However, vasoconstriction by the higher doses of NE in the diabetic rats was still enhanced even in the presence of propranolol. The cerebrovascular constriction by phenylephrine was also enhanced in the diabetic rats, while the vasoconstricting effects of clonidine, xylazine and oxymetazoline were not affected by diabetes. These results suggest that the enhanced cerebrovascular constriction by NE may be due to either the reduced response through beta-adrenoceptors or the enhanced response through alpha 1-adrenoceptors. The enhanced adrenergic constriction of the cerebral vasculature might be concerned with the high incidence of neurological deficit in stroke patients with diabetes.

Animals↗
PubMed1989

Deterioration of baroreceptor reflex by transient global cerebral ischemia in dogs.

Influence of transient global cerebral ischemia on baroreceptor reflex sensitivity (BRS) was investigated in anesthetized dogs. Cerebral ischemia was produced by the combined occlusions of the left subclavian (LSA) and the brachiocephalic (BCA) arteries with preceding ligations of the intercostal arteries (ICA). BRS was assessed by phenylephrine-induced reflex bradycardia. Ischemia of 5- and 10-min duration produced a significant decrease in BRS during the reperfusion period of 60-120 min. On the other hand, such a change was not observed following the ischemia of less than 2-min or occlusions of LSA and BCA without preceding ligations of ICA. Heart rate response to the electrical stimulation of the vagal afferent nerve was attenuated by 10-min ischemia, while response to the vagal efferent nerve stimulation and ECG parameters were not influenced. These results indicate that some regions vulnerable to the relatively short duration of cerebral ischemia may be involved in the central pathway of the baroreflex mechanism.

Animals↗
PubMed1989

Deterioration of baroreflex by transient global cerebral ischemia: its correlation with the degree of ischemia or post-ischemic hypoperfusion in the medulla oblongata.

In a canine model of transient global cerebral ischemia, the correlation between the decrease in baroreflex sensitivity (BRS) following 5-min ischemia and the degree of ischemia or post-ischemic hypoperfusion was investigated. Although the medulla oblongata and the cerebral cortex suffered a similar degree of ischemia, the extent of post-ischemic decrease in BRS was inversely correlated with the residual blood flow during ischemia in the medulla, but not with that in the cerebral cortex. A similar degree of post-ischemic hypoperfusion occurred in the medulla and the cerebral cortex. However, the extent of decrease in BRS was not correlated with the degree of hypoperfusion, and the cortical EEG was not significantly affected. These results suggest that the decrease in BRS may be due to the functional damage in the medulla and that the selective decrease in BRS without concomitant impairment of the EEG cannot be ascribed to the regional difference in the degree of ischemia or post-ischemic hypoperfusion.

Animals↗
PubMed1989

[A case of testicular infarction in the newborn].

A 6-day-old male was pointed out to have right intrascrotal swelling at birth. Surgical exploration did not reveal torsion of the spermatic cord. The testicle was suspected to have a malignant tumor and then right inguinal orchiectomy was performed. Orchiopexy of the contralateral testicle was not performed due to lack of torsion. Histological examination showed coagulation necrosis of the testicle. Sixty-three cases of testicular infarction in the newborns including our case from Japanese literature were reviewed and discussed.

Humans↗
PubMed1986

Pulmonary amyloidosis associated with systemic lupus erythematosus.

The association between amyloid and systemic lupus erythematosus is rarely reported. Our patient, a 26-year-old woman with systemic lupus erythematosus, developed steroid-resistant exertional dyspnea and pulmonary fibrosis, without proteinuria or the nephrotic syndrome. Our studies showed that she had pulmonary amyloidosis.

Adult↗
PubMed1986

[Case report of choriocarcinoma of testicular origin indicating marked efficacy of a combination chemotherapy of methotrexate, vincristine, actinomycin D, cyclophosphamide, adriamycin and melphalan].

The patient was a 26-year-old male. He was admitted to our hospital with a chief complaint of hemoptysis, cough and left scrotal mass on May 9,1984. Chest X-ray film, LAG and CT revealed multiple lung, lymph node and cerebral metastases. Based on a diagnosis of testicular neoplasm, orchiectomy was performed on May 14,1984. PVB chemotherapy (Cis-diamminedichloro-platinum, Vinblastine and Pepleomycin) was administered. Because he got worse, however, he was treated with another combination chemotherapy, consisting of Methotrexate (MTX, 100 mg/m2 intravenous push (i.v.), 200 mg/m2 12-h infusion, day 1. The dose of MTX was increased with each course. Maximum dose of MTX was 900 mg/m2/day), Vincristine (1.0 mg/m2 i.v. day 1.) Actinomycin D (10 micrograms/kg i.v. days 3.4.5), Cyclophosphamide (600 mg/m2 i.v. day 3.), Adriamycin (30 mg/m2 i.v. day 8.) and Melphalan (6 mg/m2 p.o. day 8.). After 6 courses of this regimen, distant metastases disappeared or were reduced to under one tenth, and complete remission was obtained without severe side effects. The patient was in good health on March 30, 1985.

Adult↗
PubMed1985

Changes in gonads of male and female offspring of mice receiving a continuous intravenous infusion of human chorionic gonadotropin during gestation.

In male offspring of mice given a continuous intravenous infusion of 24 IU/day hCG from days 15 to 19 of gestation (hCG-primed mice), the number of Leydig cells/testis at 15 days of age was similar to the value at 10 days, whereas the cells were decreased in number in the controls at 15 days. Mitotic rate of the interstitial tissue in 30-day-old, hCG-primed mice was lower than in the controls. In seminiferous tubules of hCG-primed mice, intratubular spaces were formed at 15 days, while the spaces in the controls were observed at 30 days. Various disorganization of the germinal epithelium occurred in some tubules of hCG-primed mice at 30-90 days. Spermatogenesis was impaired in the damaged tubules. Female hCG-primed mice showed a slightly longer estrus (24 IU/day), a higher frequency of estrus and larger number of total estrus days (120 IU/day) than those in the controls. Ovaries of 160-day-old, hCG-primed mice (24 IU/day) contained normal follicles more than those in the controls. Corpora lutea decreased in number in both groups of hCG-primed mice, showing a lower corpus-luteum occupancy. These findings suggest the occurrence of a slight degree of persistent-estrus syndrome in hCG-primed female mice.

Animals↗
PubMed1985

Calcium antagonistic properties of nicardipine, a dihydropyridine derivative assessed in isolated cerebral arteries and cardiac muscle.

Calcium antagonistic properties of nicardipine (YC-93), a 1,4-dihydropyridine derivative, were studied in isolated cerebral artery and cardiac tissues of rabbits and dogs. Calcium antagonism was assessed in electrically stimulated rabbit basilar artery. Nicardipine at 10(-7) mol/l shifted to the right the dose-response curve for Ca of the phasic contraction evoked by electrical stimulation with an alternating current, and at higher concentration it reduced the maximum tension and slope of the dose-response curve. Nicardipine inhibited the augmented contraction produced by high K, k-strophanthin and 5-hydroxytryptamine. It also caused dose-dependent inhibition of 45Ca uptake enhanced by 80 mmol/l K in dog basilar artery, and had a slight effect on the resting 45Ca uptake. In rabbit basilar artery treated with saponin, nicardipine in a dose of 10(-5) mol/l had no apparent effect on the increase in tension induced by excess Ca. Nicardipine had negative inotropic and chronotropic actions. These results suggest that nicardipine, like nifedipine, has a relative high vascular selectivity, and primarily acts by inhibiting Ca influx through the plasma membrane of vascular and cardiac tissues.

Animals↗
PubMed1985

Bronchodilating and cardiovascular effects of intraduodenally and orally administered clenbuterol in dogs.

The bronchodilating and cardiovascular effects of intraduodenally and orally administered 4-amino-alpha-[tert-butylamino)methyl]-3,5-dichlorobenzylalcohol hydrochloride (clenbuterol, NAB 365) in anesthetized and conscious dogs were investigated and compared with those of salbutamol, isoprenaline (isoproterenol) and (4-amino-3,5-dichlorophenyl) glycolic acid (M-7), a metabolite of clenbuterol. In pentobarbitalized dogs, clenbuterol, 3-100 micrograms/kg i.d., inhibited the increase in airway resistance induced by histamine in a dose-related manner; clenbuterol was approximately 2 and 100 times more potent than salbutamol and isoprenaline, respectively. The plasma level of clenbuterol increased within 15 min and reached the maximum level within 60 to 90 min, which lasted for over 4 h after administration. The inhibitory effect was abolished by pretreatment with propranolol. M-7 showed no significant effect. In anesthetized dogs, clenbuterol and salbutamol, 10 and 100 microgram/kg i.d., decreased arterial blood pressure and increased heart rate and maximum rate of rise of left ventricular pressure. Isoprenaline, 10 and 100 micrograms/kg i.d., caused no marked changes in these parameters. In conscious dogs, clenbuterol, 10 and 100 micrograms/kg p.o., and salbutamol, 100 micrograms/kg p.o., increased heart rate; the maximum responses were observed 1 to 2 h after administration and lasted for over 3 h. No marked effects were observed after salbutamol, 10 micrograms/kg p.o., isoprenaline, 10 and 100 micrograms/kg p.o., and M-7, 100 micrograms/kg p.o.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1983

Effects of prolonged administration of indenolol in hypertensive rats.

The effects of 4-week administration and subsequent 2-week withdrawal of indenolol, 50 mg/kg/day p.o., were investigated in spontaneously hypertensive rats (SHR), renal hypertensive rats (RHR) and DOCA-salt hypertensive rats (DHR) at established stage, and compared with those of propranolol, 100 mg/kg/day p.o. Indenolol and propranolol caused a marked decrease in heart rate in SHR, RHR and DHR without showing a pronounced antihypertensive activity. Both drugs did not affect the body weight gain in RHR and DHR. On the other hand, the drugs suppressed the body weight gain in SHR, which recovered during 2-week withdrawal period. Weights of the heart, kidney, liver, spleen and adrenals were not affected by the drugs. Indenolol and propranolol markedly lowered the plasma renin activity (PRA) in SHR, RHR and DHR. PRA in RHR and DHR recovered to the control level during 2-week withdrawal period, while that in SHR did not. The results indicate that indenolol produces essentially the same effect as propranolol in SHR, RHR and DHR. Prolonged administration of indenolol to SHR, RHR and DHR with established hypertension produces a marked suppression of cardiac performance and PRA with showing antihypertensive activity.

Adrenergic beta-Antagonists↗