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Biomedical subjects

M Inui

Publications and source records attributed to M Inui.

At least 163 records · Page 9Linked to original sources
PubMed1983

Effects of phospholamban phosphorylation catalyzed by adenosine 3':5'-monophosphate- and calmodulin-dependent protein kinases on calcium transport ATPase of cardiac sarcoplasmic reticulum.

To elucidate the role of 22000-dalton protein phospholamban, a putative regulator of Ca2+-dependent ATPase of cardiac sarcoplasmic reticulum, we examined the relationship between cyclic AMP- and calmodulin-dependent phosphorylation of phospholamban and their effects on ATPase activity and calcium transport of cardiac sarcoplasmic reticulum. Cardiac microsomes were incubated with [gamma-32P]ATP or unlabeled ATP, catalytic subunit of cyclic AMP-dependent protein kinase and/or exogenous calmodulin, and subsequently assayed for ATPase activity and calcium uptake by cardiac sarcoplasmic reticulum. Cyclic AMP-dependent phosphorylation of phospholamban was independent of Ca2+, whereas calmodulin-dependent phosphorylation of phospholamban was dependent on Ca2+ within a range between 0.2 and 50 microM. Cyclic AMP- and calmodulin-dependent phosphorylation of phospholamban occurred independently; when both kinases were operative, the amounts of phosphorylation were additive. Under these conditions, the phosphoproteins formed by cyclic AMP- and calmodulin-dependent protein kinases electrophoretically migrated as 11000-dalton components when sodium dodecyl sulfate-solubilized phosphoproteins were boiled prior to polyacrylamide gel electrophoresis. The ATPase activity was stimulated by either cyclic AMP- or calmodulin-dependent phosphorylation of phospholamban at Ca2+ concentrations up to 2 microM. The extents of stimulation of ATPase activity were additive when both types of phosphorylation were functional. Calcium uptake was similarly augmented by cyclic AMP- and/or calmodulin-dependent phosphorylation of phospholamban. These results indicate that Ca2+-dependent ATPase and calcium transport of cardiac sarcoplasmic reticulum are regulated by phospholamban phosphorylation catalyzed by cyclic AMP- and calmodulin-dependent protein kinases, thus suggesting a dual role of phospholamban in active calcium transport.

Biological Transport, Active↗
PubMed1983

Effect of quercetin on two-stage carcinogenesis of the rat urinary bladder.

The initiating and promoting effects of quercetin on urinary bladder carcinogenesis in male F344 rats were examined histopathologically. No tumor or hyperplasia were observed in rats given 5.0% quercetin as initiator in the diet for 4 weeks followed by 0.001% N-butyl-N-(4-hydroxybutyl) nitrosamine (BHBN) for 29 weeks. Moreover, administration of 5.0% quercetin diet for 25 weeks after initiation with 0.01% BHBN for 4 weeks did not promote urinary bladder carcinogenesis. Furthermore, no lesions were detected in rats given 5.0% quercetin diet only. These results suggest that quercetin is not carcinogenic to rat urinary bladder.

Animals↗
PubMed1983

Cardiac beat-to-beat variation as an indicator of neuropathy and the frequency of its abnormality in diabetes mellitus.

The cardiac beat-to-beat variation and the maximum constriction velocity and acceleration of the pupillary light reflex have been considered indices of parasympathetic neuropathy. The abnormality of these indices was evaluated in 191 non-diabetics and 151 diabetics. The cardiac beat-to-beat variation decreased gradually with age in non-diabetics as well as diabetics. It was small in diabetics compared to non-diabetics in corresponding age group between 10 and 59 years. In diabetics it was still smaller in the presence of peripheral neuropathy than in its absence. The overall prevalence of this abnormality was 30.1% in diabetics but only 3.0% in non-diabetics. In diabetics it rose to 40.0, 42.6 and 52.2% in the presence of motor, sensory and motor plus sensory nerve neuropathy, respectively. In 63 diabetics examined for both cardiac beat-to-beat variation and pupillary light reflex, no statistical difference was observed between the frequency of these abnormalities. These observations indicate an extremely high prevalence of abnormality in autonomic nerve function in diabetics especially in the presence of abnormality in autonomic nerve function in diabetics especially in the presence of other types of neuropathy, so that diabetics with peripheral neuropathy should be carefully examined for autonomic neuropathy and vice versa. Besides, the measurement of the cardiac beat-to-beat variation is similar in sensitivity in the detection of neuropathy to the measurement of pupillary light reflex.

Adolescent↗
PubMed1982

Actin polymerization induced by calspectin, a calmodulin-binding spectrin-like protein.

We have purified from a membrane fraction of bovine brain a calmodulin-binding protein (calspectin) that shares a number of properties with erythrocyte spectrin: It has a heterodimeric structure with Mr 240 000 and 235 000 and binds to (dimeric form) or crosslinks (tetrameric form) F-actin. We show that calspectin (tetramer) is capable of inducing the polymerization of G-actin to actin filaments by increasing nucleation under conditions where actin alone polymerizes at a much slower rate. Thus, brain calspectin behaves in the same manner as erythrocyte spectrin, supporting the idea that, in conjunction with actin oligomers it comprises the cytoskeletal meshwork underlying the cytoplasmic surface of the nerve cell.

Actins↗
PubMed1982

Anomalous origin of the left coronary artery.

Two autopsy cases of anomalous coronary artery were reported. The patients were a schoolgirl and a schoolboy, who died suddenly during physical exercise at the age of twelve. At postmortem examination in both cases the left coronary artery arose at the comissure from aorta, and in one case the left coronary ostium was completely obstructed with fibrous tissue, whereas in the other case it was severely stenotic. The cause of anomalous ostial position should be regarded as congenital, but the complete occlusion and severe stenosis at the orifice seemed to be modified by several factors--both congenital acquired. For the prevention of sudden death caused by this anomaly, cardiac angiography would have been necessary at the outset of anginal pain.

Arteries↗
PubMed1981

Clinical significance of glucagon provocation test in the diagnosis of hypergastrinemia.

Glucagon provocation test was performed in the patients with hypergastrinemia and hyperchlorhydria to investigate its diagnostic value. A paradoxical response of plasma gastrin level in the patients with the Zollinger-Ellison syndrome and a marked decrease of plasma gastrin level in the patients with gastric ulcer, duodenal ulcer, excluded gastric antrum, multiple endocrine adenomatosis, pernicious anemia and chronic renal failure were demonstrated by glucagon infusion. Glucagon provocation test, therefore, was considered to be of great value in the diagnosis of the Zollinger-Ellison syndrome, particularly, in the case of an excluded gastric antrum in which secretin provocation test caused the false positive result because of a marked increase of pancreatic secretion. Glucagon provocation test in combination with secretin provocation test, therefore, is at present the most preferable diagnostic procedure for detecting the Zollinger-Ellison syndrome.U

Adult↗
PubMed1980

Utilization of N-acetyl-L-tryptophan given intravenously to unrestrained adult rats.

The nutritional value of N-acetyl-L-tryptophan (NALT) given intravenously was examined in unrestrained adult rats. They were given solutions of 4% Vuj pattern amino acids, 24.5% glucose, vitamins and electrolytes intravenously for 10 days. They were divided into three groups; one group was then injected intravenously with complete amino acid solution (T group), one with tryptophan-free amino acid solution (TF group) and one group with complete amino acid solution but with NALT instead of tryptophan (NALT). The biological value of the NALT group was 49.6; this value corresponded to 90% of that of the T group. Excretion of injected amino acids totalled about 2.0 to 3.0% in this experiment. The effects of NALT on carcass composition, certain blood constituents and tryptophan pyrrolase activity in the liver were also examined.

Adipose Tissue↗