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Biomedical subjects

H Oka

Publications and source records attributed to H Oka.

At least 487 records · Page 27Linked to original sources
PubMed1983

Effect of secretin on protein phosphorylation in dispersed acini from rat pancreas.

Dispersed acini from rat pancreas, incubated in the presence of KH2(32)PO4 to steady state 32P incorporation into cellular proteins, were exposed to secretin. 32P incorporated into selected proteins, separated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, reached a plateau by 150 min. Effect of secretin on amylase release, cellular cyclic AMP levels and protein phosphorylation was then examined. Stimulation of amylase release was apparent with 10(-10)M and was maximal with 10(-7)M by 10 min incubation. Almost maximal increase in cellular cyclic AMP levels and 32P incorporation into selected proteins was also observed with 10(-7)M secretin by 10 min in the presence of 10 mM theophyllin. Both secretin (10(-8)M) and dibutyryl cyclic AMP (10(-3)M) induced the phosphorylation of similar proteins analyzed by counting 32P content in each peptide band after SDS gel electrophoresis. Addition of cyclic AMP (10(-6)M) to homogenates of acini also augmented 32P incorporation from [gamma-32P]ATP into similar proteins. These results indicate that secretin enhances protein phosphorylation in pancreatic acinar cells and cyclic AMP may mediate the action of secretin on protein phosphorylation.

Animals↗
PubMed1983

Simple method for analysis of apolipoproteins in high density lipoproteins by high performance liquid chromatography.

A simple and rapid method has been developed for the separation of apolipoproteins in high density lipoprotein (HDL) fractions by high performance liquid chromatography (HPLC) with gel permeation columns (G3000SW TSK GEL). The HPLC pattern monitored by A280 for a mixed solution of the HDL fraction (10 microliter) and an eluent buffer (200 microliter, 0.1 M sodium phosphate buffer containing 0.1% SDS) incubated at 60 degrees C for 5 min showed two completely separated peaks which corresponded to the major components of human HDL, apolipoprotein A-I and A-II. Moreover, quantitation of apolipoprotein A-I by our method was found to correlate well with that by a single radial immunodiffusion (SRID) assay.

Apolipoproteins↗
PubMed1983

Effect of glucagon and cyclic adenosine 3',5'-monophosphate on protein phosphorylation in rat pancreatic islets.

Isolated rat pancreatic islets, incubated in the presence of extracellular 32Pi to a state of steady 32P incorporation into cellular phosphopeptides, were exposed to glucagon, (Bu)2cAMP, or somatostatin for 10 min. In other experiments, homogenates of rat islets were phosphorylated using [gamma-32P]ATP with or without cAMP. Proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and phosphorylation of proteins was measured by liquid scintillation counting of gel slices. Glucagon (2.9 X 10(-7) M) stimulated the phosphorylation of 15 polypeptides (by approximately 20-50%) with major phosphorylation of proteins with mol wts of 138,000, 93,000, 53,000, 49,000, 35,000, 27,000 and 15,000 in intact rat islets and also stimulated insulin release by 202%. Somatostatin (6.6 X 10(-7) M) inhibited all the glucagon-stimulated phosphorylation by approximately 15-30% and also inhibited the glucagon-stimulated insulin release by 46%. (Bu)2cAMP (10(-3) M) stimulated 32P incorporation (by approximately 20-50%) into the same 15 peptides as did glucagon and also stimulated insulin release by 169%. When homogenates of rat islets were used. cAMP (10(-6) M) stimulated the phosphorylation of proteins (by approximately 25-60%) to an extent similar to that seen in the presence of glucagon or (Bu)2cAMP in intact islets. These findings indicate that the glucagon-stimulated phosphorylation of rat islet proteins may be mediated by cAMP-dependent protein kinase and that protein phosphorylation may be important in mediating the glucagon-stimulated insulin release.

Animals↗
PubMed1983

Clinical pharmacokinetics and diuretic effect of furosemide in plain tablet and retard capsule with normal subjects and cirrhotic patients.

The dissolution profiles of furosemide in various solutions were studied with plain tablet and retard capsule of furosemide. The rate constant and percent dissolution in retard capsule were lower than that in plain tablet. Clinical pharmacokinetics and diuretic effect of furosemide after oral administration of two dosage forms were also studied with 3 normal subjects and 3 cirrhotic patients. In normal subjects, the extent of furosemide absorption from retard capsule was 45% of plain tablet. The daily urine volume after oral administration of two dosage forms was comparable, however, quite different profiles were observed between these dosage forms. In patients, the extent of furosemide absorption in retard capsule was one half that of plain tablet. The dose of retard capsule was increased without adverse reactions, thus decreasing of ascites, which was not observed with plain tablet, was achieved with increasing urine volume.

Adult↗
PubMed1983

Glucagon degradation in fraction of big plasma glucagon in rats treated with carbon tetrachloride.

When whole plasma obtained from rats given carbon tetrachloride was applied to a column of Bio Gel P-30, P-150 or P-300, a large molecular form of immunoreactive glucagon (IRG), so called "big plasma glucagon" (BPG), was eluted in the void volume. Glucagon degrading activity, measured under the same conditions as for radioimmunoassay of IRG, was eluted in parallel with IRG. Since standard assay mixture containing aprotinin was used for the measurement of IRG, this degradation of glucagon might be due to an enzyme(s) other than serine proteinases. p-Hydroxymercuribenzoate depressed glucagon degradation and IRG in the BPG fractions to 20% and 30% of the control values, respectively. Other inhibitors of thiol proteinases, such as N-ethylmaleimide and leupeptin, also decreased the values for both glucagon degradation and IRG to a similar extent. However, phenylmethylsulfonyl fluoride and pepstatin had little or no effect on these values. On filtration of plasma from carbon tetrachloride-treated rats on a column of Bio Gel A-1.5m, IRG peaks between 600k and 1,200k daltons were obtained and glucagon degrading activity was again eluted with IRG. When p-chloromercuriphenyl sulfonate and N-ethylmaleimide were added to the elution buffer and assay mixtures, the glucagon degrading activity was almost completely inhibited and the values for IRG between 600k and 1,200k daltons were decreased to less than 10% of those of the control. These results indicate that more than 90% of the IRG in the fractions of BPG obtained from carbon tetrachloride-treated rats could be accounted for entirely by the degradation of immunoreactive 125I-glucagon by plasma proteinases, probably thiol proteinases. Thus we conclude that some proteinases are still active in the radioimmunoassay system of glucagon which is widely used at present, and lead apparently higher glucagon values owing to degradation of 125I-glucagon.

Animals↗
PubMed1983

A new antitumor antibiotic, awamycin.

A new antibiotic, awamycin, was isolated from the culture broth of Streptomyces sp. No. 80-217. It appeared to belong to the quinone indicator group from results of physicochemical studies and has the empirical formula C38H49NO12S. This antibiotic possessed antibacterial and antitumor activities against Gram-positive bacteria and experimental murine tumors. The antibiotic also showed direct cytotoxic activity against HeLa cells in vitro.

Animals↗
PubMed1983

Decrease in the zinc turbidity test values in patients with liver cirrhosis: a possible indicator for impending hepatocellular carcinoma.

A retrospective investigation of 21 cases of hepatocellular carcinoma with liver cirrhosis presumably of viral origin revealed a significant fall in the value of the zinc turbidity test from 15.5 +/- 6.9 (mean +/- SD) at 1 year to 11.2 +/- 2.5 units at 6 months before the discovery of the carcinoma (p less than 0.05), and a return to 16.8 +/- 7.2 units one month after the diagnosis (p less than 0.05). The values at 6, 2 and 1 month before the diagnosis were significantly lower than that for 120 control cirrhotics without hepatocellular carcinoma at 16.3 +/- 7.2 units (p less than 0.05). The fall in value occurred before or concurrently with a rise in the alpha-fetoprotein level in three patients, in whom it has been determined serially. Based on the results obtained, the decrease in the zinc turbidity test value may be used as an indicator for impending hepatocellular carcinoma in patients with liver cirrhosis.

Adult↗
PubMed1983

Liver cell membrane antibody detected by protein A and isolated rabbit liver plasma membrane in sera of patients with chronic liver diseases.

Using the plasma membrane fraction isolated from rabbit liver (RLPM), we detected non-species specific IgG antibody against liver cell surface membrane in the sera from the patients with chronic liver diseases. The sea were treated with dithiothreitol and iodoacetamide, and absorbed with sufficient amount of actin isolated from rabbit striated muscles. The antibody was detected by incubation of RLPM with the treated and absorbed sera and subsequent determination of IgG bound to RLPM by 125I-staphylococcal protein A. It was found mainly in the patients with autoimmune hepatitis (12 of 28) and liver cirrhosis (eight of 24). It occurred more frequently in HBsAg negative liver cirrhosis than in HBsAg positive forms (six of 13 vs two of 11). The frequency of the antibody was low in chronic hepatitis except autoimmune hepatitis, and primary biliary cirrhosis. Thus the antibody against RLPM was an immunological marker of autoimmune hepatitis and HBsAg negative liver cirrhosis. The occurrence did not correlate with those of anti-smooth muscle antibody, anti-nuclear antibody and anti-mitochondrial antibody. In two cases of autoimmune hepatitis, the antibody against RLPM decreased with clinical improvement induced by corticosteroids.

Adrenal Cortex Hormones↗