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Biomedical subjects

Y Imamura

Publications and source records attributed to Y Imamura.

At least 451 records · Page 25Linked to original sources
PubMed1981

Quantitative determination of 1-hexylcarbamoyl-5-fluorouracil and its metabolites in man.

A high-performance liquid chromatographic (HPLC) method for the quantitative determination of 1-hexylcarbamoyl-5-fluorouracil (HCFU) and its metabolites using mu Bondapak C18 and mu Porasil has been developed. Two mobile phases containing PIC-B7 (consisting of acetic acid and 1-heptanesulphonic acid) were used for the separation, and good separations were obtained. With methanol-water (56:44) as the mobile phase, the separation of HCFU and its three metabolites was achieved within 4 min. With methanol-water (32:68) a new metabolite, 1-omega-carboxymethylcarbamoyl-5-fluorouracil, was revealed in human plasma. The recovery of each substance was 80% or greater and the sensitivity was at the nanograms per millilitre level. The coefficient of variation was less than 3.6% for each component.

Chromatography, High Pressure Liquid↗
PubMed1981

Purification and characterization of insulin-degrading enzyme from pig skeletal muscle.

An enzyme capable of degrading insulin was purified from pig skeletal muscle and studied for its characteristics. Purification of the enzyme was successfully achieved by a combination of ammonium sulfate precipitation, chromatography of Bio-Gel P-200 and DEAE-cellulose, and, finally, ampholine isoelectrofocusing. The enzyme obtained showed 741-fold purification in its activity and a single band on polyacrylamide gel electrophoresis. The purified enzyme degraded insulin proteolytically and was sulfhydryl dependent. The Km for insulin was 70 nM. Proinsulin behaved as a competitive inhibitor for insulin degradation; its Ki was 320 nM. Glucagon was also proteolytically degraded, whereas number of other peptides, including A and B chains of insulin, were not appreciably affected by this enzyme. The molecular weight of the enzyme was estimated to be 135,000 by gel filtration on Sephadex G-200 and 60,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This enzyme and lysosomal enzymes extracted from rat liver were shown to be different, judging from their optimal pH for insulin degradation and substrate specificity. These studies demonstrate the presence of an insulin-degrading enzyme in pig skeletal muscle and suggest that this enzyme is identical to rat insulin protease in most of its biochemical properties.

Animals↗
PubMed1981

Uterine estrogen receptor assayed by the controlled pore glass (CPG) method in adult rat after steroid administration.

The interaction of estrogen and androgen was studied at the estrogen receptor level of adult rat uterus by the in vivo experiment. Both the free and total estrogen receptor in the cytosol and nucleus were assayed by the controlled pore glass beads method [2]. Testosterone was given by daily injection for 5 days to the rats treated with estradiol dipropionate (long-acting estradiol) 3 or 5 days before. In the estradiol dipropionate-treated rats the plasma estradiol concentration remained at an extremely high level for 7 days and then decreased to 5-fold of that of proestrus control by the 14th day. There was no significant change in the uterine estrogen receptor of the adult rat with a high estradiol concentration induced by testosterone.

Animals↗
PubMed1980

Localized blastoma preceding blastic transformation in Ph1-positive chronic myelogenous leukaemia: morphological and cultural studies of the transformation event.

In a patient with Ph1-positive chronic myelogenous leukaemia (CML), the development of a localized blastoma preceding generalized blastic transformation was accompanied by a reduction of granulocyte-macrophage (GM) colony forming capacity in agar of bone marrow cells as well as an increase in peripheral neutrophil alkaline phosphatase (NAP) scores. Successful transplantation of the blastoma cells into nude mice enabled extensive studies of the cell properties. The blastoma cells were double Ph1-positive cells which did not respond to human granulocyte-macrophage colony-stimulating factor (GM-CSF), and were similar to cells demonstrated in spleen and bone marrow at the terminal stage of the patient's illness. These observations clearly support the case for sequential studies of colony formation in vitro as a useful test for the early detection of disturbances in marrow function that may occur before generalized blastic transformation. Studies of the properties of the blastoma cells also provide some insight into possible mechanisms for the transformation event.

Aged↗
PubMed1980

Immunochemical studies on the insulin-degrading enzyme from pig and rat skeletal muscle.

Insulin-degrading enzyme (IDE), which proteolytically degraded insulin with a high degree of specificity, was purified from pig skeletal muscle by ammonium sulfate precipitation, chromatography on Bio-Gel P-200 and DEAE-cellulose, and finally rechromatography on Sephadex G-200 (rechromatography fraction). The enzyme was also purified by affinity chromatography (affinity fraction). Both fractions migrated as a single component at the same position on polyacrylamidegel disc electrophoresis. Antiserum against pig muscle IDE was obtained by immunization of rabbits using the rechromatography fraction. By means of antiserum, it was shown that pig muscle IDE (affinity fraction), rat muscle cytosol-, and membrane-IDE gave a precipitin band of identity in Ouchterlony double-immunodiffusion systems. Quantitative immunoprecipitin data demonstrated that the antiserum inhibited the activities of the above three IDEs compared with normal rabbit serum. These data suggest that the insulin-degrading enzyme from porcine muscle and that from rat muscle have similar immunologic properties. The antiserum described here should be a useful tool for the examination of subcellular distribution and the quantitative analysis of insulin-degrading enzyme. It may also be helpful in determining the physiologic significance of IDE.

Animals↗