Search PubMed⌕ Search

Biomedical subjects

H Kanaya

Publications and source records attributed to H Kanaya.

At least 91 records · Page 5Linked to original sources

Metabolism of D-phenylalanine and its effects on concentrations of brain monoamines and amino acids in rats--a basic study on possibility of clinical use of D-phenylalanine as an antidepressant.

The effect of D-phenylalanine on the concentrations of brain catecholamines, serotonin, beta-phenylethylamine and amino acids was examined using rats injected intraperitoneally with 200 mg/kg of D-phenylalanine. The contents of these monoamines in the rat brain were not affected by the administration of D-phenylalanine. No spectacular change was observed in the concentrations of brain amino acids except phenylalanine, which increased about four times during 30-60 minutes after the injection. This increase was attributed to the administered D-phenylalanine. To confirm the finding that D-phenylalanine did not affect the content of beta-phenylethylamine, the metabolism of D-phenylalanine was examined using D-[14C]-phenylalanine. It was proven that D-phenylalanine did not convert to beta-phenylethylamine. On the basis of these findings the antidepressant effect of D-phenylalanine was critically discussed.

Amino Acids↗

Malignant fibrous histiocytoma of the heart.

A case of cardiac sarcoma was reported. The tumor, which arose from the posterior wall of the left atrium, was demonstrated by echocardiography, contrast-enhanced computed tomography and direct observation during surgery. The tumor was successfully excised under emergency operation and was diagnosed as malignant fibrous histiocytoma after histologic examination. The patient had been free of symptoms for several months, but died of rapidly progressive congestive heart failure 6 months after surgery.

Echocardiography↗

Properties of caffeine- and potassium-contractures in fatigued frog single twitch muscle fibers.

The properties of caffeine contracture and potassium contracture in fatigued single fibers were examined in detail using frog semitendinosus muscle, Rana japonica. Fatigue was caused by repetitive stimulation at 2 Hz. The dose-response curve of caffeine contracture in the fatigued fibers was shifted toward the right; the threshold concentration of caffeine for the contracture in normal fibers was 1.5 mM, whereas that in fatigued fibers was 5 mM. However, in the presence of 25 mM K+ or 0.01% Triton X-100, caffeine contractures occurred sufficiently at the lower concentrations (3-5 mM) even in the fatigued fibers. Furthermore, in the fatigued fibers, the peak tension of the initial component of biphasic potassium contracture with 60 or 80 mM KC1 (C1 constant; 120 mM) was slightly inhibited, whereas the secondary component of the contracture was markedly inhibited. These results indicate that the permeability to caffeine of the transverse tubular membrane (T-membrane) of the fibers and the Ca influx in response to the direct depolarization of T-membrane with K+ are markedly inhibited in the fatigued fibers.

Animals↗

[Neurogenic gastrointestinal hemorrhage in hypertensive cerebral hemorrhage].

The purpose of this paper is to obtain the correlation between CT scan findings and neurogenic gastrointestinal bleeding in hypertensive intracerebral hemorrhage. Fifty patients with hypertensive intracerebral hemorrhage were operated upon during past nearly 3 years in our clinic. Of these, 27 patients (54%) showed macroscopic gastrointestinal bleeding (GI-bleeding) demonstrated by stomach catheter after the onset of hypertensive intracerebral hemorrhage. GI-bleeding was about 46% in the survived patients and about 77% in the expired ones. Most patients revealed neurogenic GI-bleeding within 9 days (85.2%) and more than half of the cases (51.9%) in 4 to 6 days after the onset. Neurogenic GI-bleeding was frequently complicated in patients with disturbed consciousness, over 60 gram hematoma (particularly 60-80 gram hematomas), severe ventricular hemorrhage and right-sided hematomas. It was also exclusively observed in patients with extension of hemorrhage into the midbrain and recurring hypertensive intracerebral hemorrhage.

Adult↗

Formation of nitroso compounds and mutagens from cinnarizine, ethambutol, piromidic acid, pyridinol carbamate and tiaramide by drug/nitrite interaction.

The formation of nitroso compounds and mutagens from 5 nitrogen-containing drugs (cinnarizine, ethambutol, piromidic acid, pyridinol carbamate and tiaramide) by drug/nitrite interaction was examined. On the reaction of 50 micrometers drug and 500 micrometers nitrite at pH 3.0--3.4 and 37 degrees C for 4 h, the considerable formation of nitroso compounds was observed for ethambutol, cinnarizine and pyridinol carbamate. The reaction product of pyridinol carbamate and nitrite was remarkably mutagenic to Salmonella typhimurium TA100 in the absence of S-9 mix. Under conditions presumed to resemble those in the stomach after ingestion of a therapeutic dose of the drug, the formation of nitroso compounds was observed for ethambutol and significant mutagenicity was detected in the reaction product of pyridinol carbamate.

Benzothiazoles↗

Hemodynamic effects of concomitant nitroglycerin ointment and nifedipine treatment in acute myocardial infarction.

Nitroglycerin ointment and nifedipine were used concurrently for vasodilator therapy in 10 patients with acute myocardial infarction. Nitroglycerin ointment 20 mg (4 cm) induced a significant reduction in pulmonary capillary wedge pressure from 14.1 +/- 1.8 (mean +/- standard error of the mean) to 12.4 +/- 1.2 mmHg (p less than 0.05) 30 min after application, while cardiac output, mean blood pressure, and systemic vascular resistance did not show a significant change. When nifedipine 10 mg was added orally, mean blood pressure significantly decreased from 99.0 +/- 6.3 to 82.8 +/- 5.9 mmHg (p less than 0.005) and systemic vascular resistance from 25.7 +/- 1.5 to 19.2 +/- 1.6 units (p less than 0.001) 30 min after; on the other hand, cardiac index significantly increased from 2.28 +/- 0.12 to 2.57 +/- 0.14 l/min/m2 (p less than 0.001). From these results, it was concluded that combined use of these two drugs was a useful and safe form of unloading therapy.

Aged↗

Formation of nitroso compounds and mutagens from tranquilizers by drug/nitrite interaction.

The formation of nitroso compounds and mutagens by drug/nitrite interaction was screened for 14 tranquilizers. The drug (0.05 M) was reacted with nitrite (0.5 M) at pH 3-3.5. After 4 h at 37 degrees C, nitroso compound formation was observed for flupentixol, chlordiazepoxide, spiperone, thiothixene, and chlorprothixene in more than 40% yield. Mutagenicity was found in the reaction products of opipramol, chlordiazepoxide, bromazepam, thiothixene, and carpipramine by the Ames assay using Salmonella typhimurium TA98 and TA100 as tester strains.

Drug Interactions↗

Intermediate-density lipoprotein and cholesterol-rich very low density lipoprotein in angiographically determined coronary artery disease.

The relationship between the concentrations of intermediate-density lipoprotein (IDL) and other lipoproteins and the extent of coronary artery disease (CAD) was studied in 182 consecutive patients evaluated by selective coronary cineangiography. On univariate analysis, the extent of CAD correlated significantly and positively with very low density lipoprotein (VLDL) cholesterol, IDL cholesterol and low-density lipoprotein (LDL) cholesterol, and negatively with high-density lipoprotein (HDL) cholesterol. Analysis of four subgroups divided by IDL cholesterol and LDL cholesterol levels indicated that moderately increased levels of IDL cholesterol were closely associated with a high frequency of CAD. Moreover, multi-variate regression analysis demonstrated that IDL cholesterol for men, LDL cholesterol for men and women and HDL cholesterol for men were significant variables of use in the final weighting procedure. IDL cholesterol was closely associated with cholesterol-rich VLDL. This study shows that IDL and cholesterol-rich VLDL combine to contribute to the development of CAD.

Adult↗

The effects of parabiosis on serum and kidney glycosidase activities in spontaneously diabetic mice.

Spontaneously diabetic non-obese mice of the ICR strain were newly inbred in Shionogi laboratory, Japan. Animals became diabetic suddenly, more frequently and severely in females. Blood glucose levels were 452 +/- 73 mg/100 ml with serum insulin levels of less than 1.0 microU/ml in the fed state. Parabiosis with normal control ICR mice for 2 weeks decreased the blood glucose level to 260 +/- 51 mg/100 ml (P less than 0.01) and resulted in serum insulin levels of 46.0 +/- 18.0 microU/ml (P less than 0.01). Kidney homogenate beta-N-acetylglucosaminidase and beta-galactosidase activities were reduced in diabetic mice (42% and 44% decreases respectively) (P less than 0.025 and P less than 0.001), and restored almost to normal after 2 weeks of parabiosis. Renal alpha-mannosidase activity was decreased 43% (P less than 0.001) in the diabetic mice but unaffected by parabiosis. Serum beta-N-acetylglucosaminidase, beta-galactosidase and alpha-glucosidase activities were significantly increased in diabetic mice (179%; 233% and 58% increase respectively) (P less than 0.005, P less than 0.001 and P less than 0.001), and returned to normal with parabiosis.

Animals↗

Primary cerebral malignant lymphoma of the histiocytic type.

A 60-year-old house wife complained of anorexia, headaches and vomiting for several months. Later she developed disturbances in gait. At the terminal stage of her clinical course, 3 masses in the cerebrum and one in the cerebellum were detected by angiography and CT-scans. At autopsy, 3 masses in the frontal lobes, and one in each thalamus and still another in the cerebellum were found. They were accompanied with necrotic and haemorrhagic changes. Tumor cells were large irregular or round in shape, and showed metallophilia by the silver impregnations for reticlum cells and microglia. Some of them were multinucleated giant cells. Tumor cells showed occasionally phagocytic activity. Perivascular infiltration of tumor cells was marked around the tumor masses.

Brain↗