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Biomedical subjects

A Watanabe

Publications and source records attributed to A Watanabe.

At least 991 records · Page 55Linked to original sources
PubMed1981

Determination of nitrite in human, cow and market milks by gas-liquid chromatography with electron-capture detection.

A simple and practical method for the determination of very small amounts of nitrite in human, cow and market milks is described. It is based on the reaction of nitrate with 1-hydrazinophthalazine in acidic solution to form tetrazolophthalazine, a stable compound which can be extracted with an organic solvent and then determined by gas-liquid chromatography with electron-capture detection using a column of 3% OV-225 on Chromosorb W HP; the detection limit for nitrite was 2 ng/ml. The procedure for determining nitrite in milks involves extraction with solvent, followed by further clean-up by alumina column chromatography; the detection limit is about 4 ppb and recovery in human, cow and market milks was satisfactory. The method makes possible a micro-assay for nitrite. The tetrazolophthalazine was identified by its elemental composition, melting point and by combined gas chromatography-mass spectrometry.

Animals↗
PubMed1981

Treatment of liver cirrhosis with branched chain amino acid-supplemented diet.

Seven patients with compensated liver cirrhosis were tested for branched chain amino acid (BCAA)-supplemented diet to evaluate dietetic therapy of the disease. Serum prealbumin and albumin levels, hepaplastin tests, nitrogen balance and molar ratio of serum BCAA and aromatic amino acid (AAA) were mostly improved during 2 weeks of the special diet supplemented with daily 5 g BCAA in three meals. The results indicate that BCAA-supplemented diet may be useful for treatment of impaired protein metabolism frequently observed in cirrhotic patients.

Amino Acids, Branched-Chain↗
PubMed1981

Alteration of Coding Properties of Polysome-Associated Messenger RNA in Potato Tuber Slices during Aging.

Kinetics of polysome formation, translational capacity, and coding properties of polysome-associated messenger RNA were investigated in potato tuber tissue discs during aging. Polysome content rapidly increased immediately after slicing from 14% of total ribosomes in freshly sliced discs to 55% within 12 hours of aging. The amount of polysomal RNA also increased 5-fold during this period. Translational capacity of polysome-associated messenger RNA increased in parallel with the increase in content of polysomal RNA of the tissue discs when measured in a wheat germ cell-free system. Analysis of the in vitro translation products by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the majority of polypeptides coded by the messenger RNA did not vary greatly during the period of rapid polysome formation. Three types of messenger RNA were found to change in amount during that period: those which appeared only after aging, those which disappeared during aging, and those which disappeared early but reappeared later in the aging period.

Journal Article↗
PubMed1981

Enzymic Mechanism of Starch Breakdown in Germinating Rice Seeds: 10. IN VIVO AND IN VITRO SYNTHESIS OF alpha-AMYLASE IN RICE SEED SCUTELLUM.

Scutellar tissues were dissected from germinating rice seeds and the incorporation of [(35)S]methionine into the alpha-amylase molecule was examined by in vivo and in vitro assay systems. Immunoprecipitation with monospecific anti-alpha-amylase immunoglobulin G raised against the purified enzyme preparation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography were used to identify alpha-amylase and its possible precursor molecule. Using freshly prepared scutellar tissues, it was demonstrated that alpha-amylase is synthesized de novo in the scutellar epithelium and secreted into endosperm. The synthesis of alpha-amylase directed by the polyadenylic acid-containing ribonucleic acid isolated from the scutellar tissues was also established using the translation system of either wheat germ extract or reticulocyte lysate. The immunoprecipitable product obtained in the in vitro translation system was smaller in molecular weight than that synthesized in vivo on the basis of mobilities in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Results are discussed in relation to the processing of the nascent polypeptide precursor of the enzyme molecule and the introduction of the oligosaccharide chain to the cleaved polypeptide to make up the mature form of alpha-amylase.

Journal Article↗
PubMed1981

Magnesium and potassium interrelationships, experimental and clinical.

1) Coexisting Mg and K deficiency may occur with greater frequency than has been previously appreciated. 2) Profound hypokalemia, or refractoriness to K repletion or coexisting hypokalemia and hypocalcemia should suggest the possibility of concurrent Mg and K depletion. 3) The identification and treatment of concurrent K and Mg depletion is especially important in patients with congestive heart failure because of problem of digitalis toxicity. 4) We believe that the role of magnesium in optimizing cardiac function remains to be elucidated, identification and treatment of coexisting Mg and K depletion will be facilitated by making serum Mg a routine electrolyte determination together with Na, K, Cl, CO2.

Adult↗
PubMed1981

Effects of ML-236b (compactin) on sterol synthesis and low density lipoprotein receptor activities in fibroblasts of patients with homozygous familial hypercholesterolemia.

We studied biochemical genetics of low density lipoprotein (LDL) receptor mutations in fibroblasts from six homozygous and five heterozygous patients with familial hypercholesterolemia (FH). Three of six homozygotes are receptor-negative type and the other three homozygotes are receptor-defective type. In the cells from three receptor-negative homozygotes, the receptor binding, internalization, and degradation of (125)I-LDL were 0.5+/-0.3 ng/mg protein (mean+/-SEM), 14+/-8 and 8+/-6 ng/mg protein per 6 h (four normal cells; 44+/-3, 386+/-32, and 1,335+/-214 ng/mg protein per 6 h), respectively. In the cells from three receptor-defective homozygotes, the receptor binding, internalization, and degradation of (125)I-LDL were 6+/-2, 29+/-8, and 90+/-32 ng/mg protein per 6 h, respectively. In these six homozygotes, two pairs of siblings are included. Two siblings in the same family were classified as receptor-negative and two siblings in another family were classified as receptor-defective. The receptor-negative phenotypes and the receptor-defective phenotypes bred true in individual families. The cells from five heterozygotes showed approximately 46% of the normal activities of receptor.ML-236B, competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase), completely inhibited the incorporation of [(14)C]acetate into digitonin-precipitable sterols in fibroblasts from normal subjects and heterozygous and homozygous patients with FH with the concentration of 0.5 mug/ml. However, at 0.05 mug/ml of ML-236B sterol synthesis in fibroblasts from homozygotes was not completely suppressed in contrast to normal and heterozygous cells. Moreover, after preincubation with 0.05 mug/ml of ML-236B for 24 h in medium containing lipoproteins, sterol synthesis in the cells from receptor-negative homozygote showed 75% of the initial activity compared with that of 25% without preincubation. In the cells from a normal subject and a heterozygote, sterol synthesis was inhibited even after preincubation. These results suggest that (a) the inhibitory effect of ML-236B is overcome in homozygote cells by their high intracellular levels of HMG-CoA reductase and (b) that a higher dose of ML-236B may be required to lower serum cholesterol levels in FH homozygotes than in heterozygotes.

Anticholesteremic Agents↗
PubMed1981

Inverse correlation between urinary 17-hydroxycorticosteroid (17-OHCS) excretion and thyrotropin-releasing hormone (TRH)-induced thyrotropin (TSH) response in disorders of adrenocorticotropic hormone (ACTH) and adrenal secretion.

A TRH test was performed in patients with Cushing's syndrome and isolated ACTH deficiency, and serum TSH was measured. A TRH-induced TSH showed low response in patients with Cushing's syndrome but showed excessive response in patients with isolated ACTH deficiency. However, in both diseases TRH-induced TSH response showed a tendency to normalize after the treatment. Urinary 17-OHCS excretion was measured in patients with Cushing's syndrome and isolated ACTH deficiency before and after the treatment. There was a definite inverse correlation between ;the logarithm for urinary 17-OHCS excretion and the peak TSH response to TRH. These results suggested that glucocorticoids regulate not only ACTH but also TSH secretion.

17-Hydroxycorticosteroids↗
PubMed1981

Syntheses of 9-substituted josamycin, 13-substituted isojosamycin and their tetrahydro derivatives.

Derivatives of josamycin and isojosamycin modified at C-9 and C-13 have been prepared by reaction sequences involving treatment of josamycin with alcohols, phenol or 1-methyl-1H-tetrazol-5-ylthiol in acidic media. Several tetrahydro derivatives of josamycin and isojosamycin have also been prepared by reaction sequences involving catalytic hydrogenation. From the 1H NMR studies, it was found that the conformation of the macro-lactone portion of 13-O-methylisojosamycin dimethylacetal, a key intermediate, is flexible and changeable with variation of the solvent.

Anti-Bacterial Agents↗
PubMed1981

Altered dynamics of alpha-fetoprotein production following pyridoxine and adenosine 5'-triphosphate administration to cirrhotic patients with or without primary hepatomas and to liver-injured and hepatoma-bearing rats.

In 12 cirrhotic patients who developed primary hepatocellular carcinomas during long-term follow-up, surveillance by frequent serum alpha-fetoprotein (AFP) measurements was not useful for their earlier detection. Difficulty was encountered in deciding whether or not hepatomas had already developed in cirrhotic patients with serum AFP levels over 200 ng/ml. Simultaneous injections of pyridoxine and adenosine 5'-triphosphate (ATP) resulted insignificant decreases of elevated serum AFP levels in carbon tetrachloride (CCl4)-injured rats but in 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB)-induced hepatoma-bearing rats. On clinical application of this procedure, it was found that cirrhotic patients without hepatomas could be differentiated from those with primary hepatomas since in the former a clear reduction of AFP levels following the administration of pyridoxine and ATP took place. This may be a new approach to the earlier diagnosis of primary hepatomas in cirrhotic patients with elevated serum AFP levels.

Adenosine Triphosphate↗
PubMed1981

A rapid method for monitoring serum neutral amino acid concentrations in severe liver disease.

A rapid liquid chromatographic method for monitoring the 6 neutral amino acid levels in serum, valine, leucine, isoleucine, tyrosine, phenylalanine and methionine, has been developed for use as one of the routine clinical laboratory tests for patients with severe liver disease requiring urgent treatment. This simple method would provide much valuable information for the selection of therapy, prediction of impending coma and evaluation of the patient's response to treatment, as well as an analysis of pathophysiology and prognosis.

Amino Acids↗