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Biomedical subjects

M Usami

Publications and source records attributed to M Usami.

At least 253 records · Page 14Linked to original sources
PubMed1985

Properties of protein kinases in brain coated vesicles.

Coated vesicles prepared from bovine brain contained cyclic nucleotides- and Ca2+-calmodulin-independent protein kinases which in the presence of Mg2+ catalyzed the phosphorylation of an endogenous 48,000 Mr protein of coated vesicles (C-48), phosvitin and troponin T. Phosvitin was phosphorylated either in the presence of ATP or GTP. The phosphorylation of C-48, on the other hand, was specific for ATP. Heparin inhibited the phosphorylation of phosvitin but not that of C-48. Mn2+ inhibited the phosphorylation of phosvitin, while Mn2+ substituted for Mg2+ in the phosphorylation of C-48. When the coated vesicles were prepared in the presence of NaF, C-48 contained 2.5-2.8 mol of phosphate/mol. On incubation with Mg2+ and ATP, C-48 incorporated 1.2-1.6 mol of phosphate/mol. With C-48 as a substrate, the value of its apparent Km for ATP was 6 microM. With phosvitin as a substrate, the value of its apparent Km was 20 microM. The phosphorylated amino acid residues in the phosvitin were identified as serine and threonine. Phosphothreonine was detected in C-48. These results suggest that brain coated vesicles possess two different classes of protein kinase, a casein kinase II and C-48 kinase.

Adenosine Triphosphate↗
PubMed1985

Clinical thermofiltration: initial application.

The first clinical thermofiltration procedures (plasma filtration near or above normal physiologic temperature) were performed on a secondary hypercholesterolemia patient. The intent of this filtration scheme is the selective removal of low density lipoproteins (LDL) and maintenance of high density lipoproteins (HDL) and other essential plasma proteins including albumin. The EVAL 4A filter, at a filtration temperature of 37 degrees C, was selected for on-line thermofiltration. The sieving coefficients of LDL + very low density lipoproteins (VLDL) cholesterol, HDL cholesterol, and albumin were 0.02, 0.75, and 0.78, respectively. These results are comparable to in vitro filtration tests using the plasma of the same patient. This system is simple to apply and does not require replacement solution. Compared with plasma exchange, a high return of HDL and other essential plasma solutes can be returned to the patient by this method.

Adult↗
PubMed1985

[Effect of mazindol on insulin and glucagon secretion in ventromedial hypothalamic obese rats].

The effect of mazindol on insulin and glucagon secretion was studied in ventromedial hypothalamic lesioned (VMH) obese rats with hyperinsulinemia and VMH sham rats. Three weeks after the VMH or sham operation, VMH and sham rats were divided into two groups: one was fed diet containing mazindol (50 mg/kg) and the other was fed diet without mazindol. They were housed three more weeks before the experiment. Mazindol reduced significantly body weight increase and calorie intake in VMH rats, but not in sham rats. In addition, the fasting plasma insulin level and the arginine-induced insulin secretion in VMH rats treated with mazindol were significantly lower than those in the VMH rats without treatment of mazindol. On the other hand, in both in vivo and in vitro experiments, mazindol produced no significant change in the insulin secretion of sham-operated rats. These results suggest that mazindol suppresses hypersecretion of insulin in VMH rats probably through an anorectic effect and/or suppression of vagal hyperactivity.

Animals↗
PubMed1985

Effect of a high-protein diet on insulin and glucagon secretion in ventromedial hypothalamic (VMH) lesioned rats.

The effects of a high-protein diet on insulin and glucagon secretion in ventromedial hypothalamic (VMH) lesioned and sham-operated (sham) rats were studied in vivo as well as in perfusate from isolated pancreas. Two weeks after VMH destruction or sham operation, the rats were given either a balanced diet (protein 27%, carbohydrate 61%, fat 12%) or a high-protein diet (protein 55%, carbohydrate 30%, fat 15%) for the following 2 weeks. The calorie intake and body weight changes after the commencement of the diets were almost the same in the groups of VMH lesioned rats, but these were much greater than those in the two sham-operated groups. Fasting blood glucose, plasma insulin, and plasma glucagon concentrations were also similar between the two VMH groups, but in the sham-operated rats fasting blood glucose and plasma insulin concentrations of those rats on high-protein diet were significantly increased when compared to those on balanced diet. In the isolated, perfused pancreas, an arginine-induced excess insulin and glucagon secretion was not significantly different between the VMH lesioned rats. An arginine-induced rise in insulin concentration in the sham-operated rats on high-protein diet was significantly higher than for rats on balanced diet. We therefore suggest that hyperinsulinemia already produced in the VMH lesioned rats may not be influenced by the change in the composition of the dietary protein and carbohydrate.

Animals↗
PubMed1985

[Nonsurgical treatment of renovascular hypertension by percutaneous transluminal angioplasty].

A case of renovascular hypertension treated with percutaneous transluminal angioplasty is reported. Our patient was a 22-year-old housewife with 90 per cent stenosis of the right renal artery due to fibromuscular dysplasia. The renal artery was dilatated by percutaneous transluminal angioplasty with a Grützig balloon catheter to 25 per cent stenosis. Five hours after the procedure, blood pressure decreased from 180/114 mmHg to 130/95 mmHg; one day after, plasma renin activity fell from 4.7 ng/ml/hr to 1.7 ng/ml/hr. The patient was rehospitalized six months after percutaneous transluminal angioplasty to examine restenosis of the dilatated renal artery. Although her blood pressure remained normotensive and plasma renin activity was normal, replasty was performed since selective renal arteriography revealed 50 per cent stenosis.

Adult↗
PubMed1985

Apheresis: clinical response to patients unresponsive to conventional therapy.

Ten of 13 (76.9%) rheumatoid arthritis (RA) patients having intensive cryofiltration treatment showed improvement and 5 of 7 (71.4%) of RA patients treated on maintenance cryofiltration therapy showed improvement. Encouraged by these results, 2 centers were established for controlled trial studies of RA patients. Four of 4 (100%) rheumatoid vasculitis patients treated by cryofiltration and 4 of 7 (57.1%) patients treated with plasma exchange showed clinical improvement. An SLE patient with thrombocytopenia showed a dramatic rise in platelet count during intensive (3 day/wk) plasma exchange treatments despite little prior response to drugs, platelet infusions and splenectomy. Plasmapheresis was effective in improving clinical symptoms and lipid abnormalities in a primary sclerosing cholangitis patient without causing hypoproteinemia during the long-term therapy (4 yrs).

Adult↗
PubMed1985

[VM-26 salvage therapy for refractory or recurrent germinal testicular cancers].

Four patients with refractory or recurrent germinal testicular cancers were treated with the combination of VM-26 and cis-platinum, and two of them also in combination with radiation therapy. Two complete responses and two partial responses were observed. One partial response was rendered no evidence of disease by sequential radiation therapy. Three of the patients remained to have no evidence of disease from 16, 21 and 22 months. Toxicity was tolerable. VM-26 is an active drug in germinal testicular cancers and plays an important role in salvage therapy, for refractory or recurrent cases.

Adult↗
PubMed1984

Protein kinase and its endogenous substrates in coated vesicles.

Coated vesicles prepared from bovine brains contained a protein kinase activity which catalyzed the phosphorylation of endogenous structural proteins, Mr 150 000, 120 000, 48 000 and 32 000. An endogenous protein, Mr 48 000 was most strongly phosphorylated by this kinase. This protein kinase also phosphorylated exogenous proteins, phosvitin intensely and casein slightly but not histone or protamine. The enzyme activity was independent of cyclic nucleotides or Ca2+/calmodulin. Mg2+ stimulated the kinase activity. Some divalent cations were substituted for Mg2+; the potency decreased in the order Mn2+, Mg2+, Co2+, Ca2+, Zn2+. Two separate subfractions, the outer coat and the inner vesicle (core), were prepared from coated vesicles by a urea treatment followed by sucrose density gradient centrifugation and dialysis. The kinase activity was found predominantly in the coat subfraction.

Animals↗
PubMed1984

Somatostatin, glucagon, and insulin secretion from isolated perfused pancreas of new genetically obese hyperglycemic rats.

Insulin, somatostatin, and glucagon release from the perfused pancreas was studied in the newly developed genetically obese hyperglycemic hyperinsulinemic (Wistar fatty) rat. Insulin and somatostatin levels rose significantly compared to those in lean littermate controls during arginine infusion. The glucagon increase, however, was significantly less when total amounts during arginine infusion were calculated. These results show that hypersecretion of insulin and somatostatin in vitro may suppress glucagon release in Wistar fatty rats.

Animals↗