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Biomedical subjects

H Matsui

Publications and source records attributed to H Matsui.

At least 775 records · Page 43Linked to original sources
PubMed1982

Purification and properties of bovine brain dopamine beta-hydroxylase.

Dopamine beta-hydroxylase (DBH) was purified from bovine brain by a series of steps including extraction with 0.5% Triton X-100, ammonium sulfate fractionation, and serial chromatographies with Concanavalin A (Con A)-Sepharose, Biogel A-1.5 m, DEAE-Sephadex, and phenyl-Sepharose. The overall purification was approximately 4200-fold and the final specific activity was 147 nmol/min/mg protein. Bovine brain DBH was apparently a glycoprotein and interacted with immobilized Con A. Furthermore, the enzyme bound to phenyl-substituted agarose by hydrophobic interaction. An approximate molecular weight was estimated to be 400,000 by gel filtration; the protein eluted earlier than bovine adrenal DBH with a molecular weight estimated to be 290,000. The Km values toward tyramine and ascorbate were 1.53 and 1.42 mM, respectively, the optimal pH was 5.0 in the presence of 20 mM tyramine as substrate. Immunological titration studies indicated that bovine brain and adrenal DBH had common antigenic sites. Our data showed a close similarity between the bovine brain and adrenal enzymes.

Animals↗
PubMed1982

Pharmacokinetics of the cephalosporin SM-1652 in mice, rats, rabbits, dogs, and rhesus monkeys.

The pharmacokinetics of SM-1652 were studied in mice, rats, rabbits, dogs, and rhesus monkeys. The plasma half-lives of SM-1652, administered intravenously at a dose of 20 mg/kg, were 11.0 min in mice, 26.0 min in rats, 65.8 min in rabbits, 72.6 min in dogs, and 150.9 min in monkeys. The 24-h urinary excretion of SM-1652 was 30 to 35% of the dose in mice and rats, 70 to 75% in rabbits and dogs, and 45% in monkeys. Biliary excretion of the antibiotic over a 24-h period was 60 and 19% in rats and rabbits, respectively; it was 19% in dogs over a 9-h period after SM-1652 administration. Approximately 95% of the intravenous dose of SM-1652 was recovered as the unchanged form in the urine and bile of rats and rabbits. The binding of SM-1652 to serum protein was 44.0% in mice, 46.0% in rats, 90.4% in rabbits, 93.2% in monkeys, 30.0% in dogs, and 96.3% in humans.

Animals↗
PubMed1982

[Properties and mechanism of hyperlipidemia induced in rabbits by tributyltin fluoride].

Male Japanese white rabbits were given tributyltin fluoride (TBTF) by gastric intubation with a single dose of 100 mg/kg body weight and their lipid and glucose metabolisms were investigated. After administration of TBTF, a reversible, but remarkable increase of lipids in plasma, particularly of triglycerides and total cholesterol, was observed. Ultracentrifugation of plasma lipoproteins revealed a marked increase in chylomicron+VLDL (very low density lipoprotein) fraction. Lipoprotein lipase (LPL) activity in postheparin plasma reduced significantly (p less than 0.02) to the levels of about 50% of the control. Fasting blood glucose level was elevated and a significant inhibition of insulin (IRI) release in response to the intravenous glucose infusion was observed in TBTF treated rabbits, but the level of blood glucose and the degree of inhibition of IRI release were low compared with those of triphenyltin fluoride treated rabbits, in which much greater fasting hyperglycemia was observed. Microscopic examination of pancreas, kidneys and thyroid gland did not reveal histological alterations contributing to the hyperlipidemia. These results suggest that hyperlipidemia induced in rabbits by tributyltin fluoride is due to decreased LPL activity. The decrease in LPL activity seems to be related to the inhibition of insulin release from islets by TBTF.

Animals↗
PubMed1982

[Pathogenesis of hyperlipidemia and fatty liver of rabbits induced by methyl iodide. Increased synthesis and secretion of triglyceride in the liver].

Male Japanese white rabbits were injected subcutaneously with methyl iodide (57 mg/kg body weight/day) on two successive days and their lipid metabolism was investigated 48 hr after the last injection. The plasma triglyceride levels increased from the preinjection average of 56.1 mg/dl to 246.0 mg/dl on an average, the individual values being greatly variable. Analysis of lipoprotein profile of plasma showed a significant increase of very low density lipoproteins (VLDL). Lipolytic activities in postheparin plasma did not change. However, rates of triglyceride secretion into plasma, measured by Triton WR 1339 injection method, were significantly higher in the animals treated with methyl iodide than in the controls. Histological investigation of the liver showed diffuse fat deposits in the hepatocytes without any destructive and inflammatory changes. The results indicate that hyperlipidemia and fatty liver of rabbits induced by methyl iodide is related to the elevation of triglyceride synthesis and its secretion in the liver.

Animals↗
PubMed1982

Factors inhibiting cell proliferation in rat liver cytoplasm.

Two factors from normal rat liver cytoplasm inhibited the proliferation of cultured L-929 fibroblasts. One was arginase, the other was a small molecular weight inhibitor stable to trypsin and heat treatment. The small molecular weight inhibitor inhibited the protein and DNA synthesis of L-cells. Inhibition of DNA synthesis was thought to be secondary to the inhibition of protein synthesis.

Animals↗
PubMed1981

Highly sensitive assay for dopamine-beta-hydroxylase activity in human cerebrospinal fluid by high performance liquid chromatography-electrochemical detection: properties of the enzyme.

This paper describes a new, sensitive assay for dopamine-beta-hydroxylase (DBH) activity in human cerebrospinal fluid (CSF), serum and brain tissues by high performance liquid chromatography (HPLC) with electrochemical detection (ED). Dopamine (DA) was used as a substrate and was incubated under optimal conditions. Norepinephrine (NE) formed enzymatically from DA was isolated by a double-column procedure, the first column of Dowex-50-H+ and the second column of aluminum oxide. NE was adsorbed on the second aluminum oxide column and then eluted with 0.5 M-hydrochloric acid and assayed by HPLC-ED. Epinephrine (EN) was added to each incubation mixture as an internal standard, and this assay was therefore highly reproducible. The peak height in HPLC was linear from 500 fmol to 100 pmol of NE and EN. The lower limit of detection for NE formed enzymatically was about 30 pmol, which indicated that the sensitivity of this procedure was comparable to that of radioassay procedures. We applied the method to measurement of the activity of and examination of some of the characteristics of DBH in human CSF. DBH activity in CSF of Parkinsonian patients was lower than that of control patients. The properties of DBH in human CSF were similar to those in serum and adrenal medulla.

Adrenal Medulla↗
PubMed1981

Adrenal medullary secretory response to pontine and mesencephalic stimulation in the rat.

Adrenal medullary secretion in response to electrical stimulation of the pons and midbrain was investigated in pentobarbital-anethetized rats. Adrenal venous blood samples were collected and analyzed for epinephrine and norepinephrine by the fluorometric method. Stimulation of the dorsolateral areas of the pons and midbrain resulted in a significant increase in epinephrine secretion with or without a significant increase in norepinephrine secretion. Most of the responsive areas were localized near the main sensory nucleus and motor nucleus of the trigeminal nerve. It may be suggested that in the pons and midbrain there exist central nervous system mechanisms for the regulation of the adrenal medullary secretion.

Adrenal Medulla↗
PubMed1981

The effect of age on cadmium retention in organs of hamsters.

Age difference of cadmium retention was investigated in hamsters after a short term cadmium exposure. Three types of organs were identified in relation to cadmium retention, i. e., the liver and testes retained an increasing amount of cadmium with increasing age, the kidney and heart showed a gradual decrease in the retention after a transient increase in young ages and the bone showed no retention. These changes seemed to be related to the de novo synthesis of metallothionein in the organ.

Aging↗
PubMed1981

Increased activity of a neutral protease in cytosol from rat hepatoma induced by N-2-fluorenylacetamide.

A protease active with N-alpha-benzoyl-DL-arginine-p-nitroanilide with an optimum pH of 7.3 has been found in the cytosol of rat liver. The activity of this protease increased in N-2-fluorenylacetamide-induced hepatoma as well as in fetal liver. It has been purified from normal liver and hepatoma about 200-fold. Its molecular weight is estimated by gel filtration to be about 200,000 in each tissue. The protease activity is unaffected by chymostatin, pepstatin, soybean trypsin inhibitor, and p-chloromercuribenzoate. Antipain, leupeptin, tosyl-L-lysine chloromethyl ketone, and phenylmethylsulfonyl fluoride inhibit the protease activity. This protease appears to be a serine protease.

2-Acetylaminofluorene↗
PubMed1981

Longitudinal study of aerobic power in superior junior athletes.

The effects of endurance training on aerobic power, and the relationship between aerobic power and running performance were investigated in 11 junior runners over a period of 5-to-7 years, starting from the age of 14. Aerobic power was measured using treadmill running and a protocol that involved increasing speed. The six subjects who comprised group I were those who continued competitive training, while the five in group II had stopped training by the age of 18. The subjects in group I demonstrated greater aerobic power (l x min-1) and better running performance than those in group II. Aerobic power for group I increased from 3.54 l x min-1 (65.4 ml x kg-1 x min-1) to 4.49 l x min-1 (75.5 ml x kg-1 x min-1) between the ages of 14.8 and 18.8 yr. The increase in l x min-1 and ml x kg-1 x min-1 was statistically significant (p less than 0.01, p less than 0.05). The greatest aerobic power found in subject A corresponds to the data from world-class runners: 3.63 l x min-1 (61.5 ml x kg-1 x min-1) at age 14.7 yr; 4.67 l x min-1 (74.6 ml x kg-1 x min-1) at 17.8 yr; and 5.04 l x min-1 (76.3 ml x kg-1 x min-1) at 20.7 yr. After their training was discontinued, aerobic power for those in group II decreased to the level of ordinary schoolboys. Improvement in running performance was closely related to the increase of aerobic power in l x min-1. Superior running performance seems to be associated with high aerobic power in l x min-1, rather than in ml x kg-1 x min-1 for junior runners.

Adolescent↗