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Biomedical subjects

M Kawamura

Publications and source records attributed to M Kawamura.

At least 865 records · Page 48Linked to original sources
PubMed1984

Changes in plasma gastrin and secretin levels after pancreaticoduodenectomy.

The kinetics of secretion of gastrin and secretin before and after pancreaticoduodenectomy were studied. Prior to pancreaticoduodenectomy, gastrin secretory function was within the normal range; it was significantly reduced postoperatively. Preoperatively, patients had elevated basal levels of secretin with depressed reactivity. During pancreaticoduodenectomy, the upper part of the jejunum should be preserved as far as possible. Ulcers occurring after pancreaticoduodenectomy are more probably due to vagus nerve activity and other factors rather than to an imbalance between gastrin and secretin.

Adult↗
PubMed1983

Identification of the mRNA and polypeptide subunit for prostaglandin endoperoxide synthase from mouse mastocytoma P-815 cells.

Cloned mouse mastocytoma P-815.2-E-6 cells are barely able to synthesize prostaglandins because of a lack of prostaglandin endoperoxide synthase activity. However, the addition of sodium n-butyrate at 1 mM induces synthesis de novo of prostaglandins in this cell line. Employing this system, we could isolate an mRNA for prostaglandin endoperoxide synthase by a combination of cell-free translation and immunoprecipitation. The antibody, prepared in rabbit by injecting purified prostaglandin endoperoxide synthase from bovine vesicular gland, was shown to cross-react with the corresponding enzyme from 2-E-6 cells. The poly(A)-containing mRNA has a sedimentation coefficient of 17S and codes for a single polypeptide chain of Mr 62 000 as estimated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The Mr of the mouse polypeptide chain appears very similar to that of the purified carbohydrate-free prostaglandin endoperoxide synthase from sheep vesicular gland. These findings are a contribution to the isolation of the gene for prostaglandin endoperoxide synthase.

Animals↗
PubMed1983

Prostaglandin D2 strongly inhibits growth of murine mastocytoma cells.

The effects of prostaglandins D2, E2 and F2 alpha on the growth of murine mastocytoma cells were investigated by adding them to cultures at concentrations of 0.1 - 50 micrograms/ml. At the same time, their effects on DNA synthesis were investigated. Of these prostaglandins, prostaglandin D2 was the strongest inhibitor of mastocytoma cell growth and at 10 micrograms/ml of medium it also caused cell death within 24 h. Prostaglandin E2 at this concentration only inhibited cell growth. Prostaglandin F2 alpha had no effect on cell growth at concentrations of up to 50 micrograms/ml. These findings show that prostaglandin D2 is a strong anti-proliferative agent.

Animals↗
PubMed1983

Cloning of a LEU gene and an ARS site of Candida maltosa.

Gene libraries of DNA from an n-alkane-assimilating yeast strain, Candida maltosa IAM12247, were constructed, using Escherichia coli plasmid vector pBR322. A LEU gene from C. maltosa was cloned, and found to complement leu- mutations in E. coli and Saccharomyces cerevisiae. In E. coli, the LEU gene in the cloned yeast DNA fragment was efficiently expressed when inserted into the vector in one orientation, while in the other orientation, it was expressed only weakly. In S. cerevisiae, the Candida LEU gene was efficiently expressed when inserted into a shuttle vector pRC3 in both orientations, suggesting that the isolated Candida DNA fragment contains a promoter sequence of Candida in front of the LEU gene, which is operative in S. cerevisiae but not in E. coli. In addition, our data suggest that the cloned LEU fragment also contains an ARS (autonomously replicating sequence) site of C. maltosa.

Candida↗
PubMed1983

Are amorphous aggregates of actin formed at the initial stage of polymerization?

Amorphous aggregates of actin of various sizes were observed under an electron microscope, when actin polymerization was inhibited or retarded by EDTA or by low salt concentration. It was first thought that these aggregates could be intermediate complexes of actin in the process of polymerization. These aggregates were, however, present in usual G-actin solution as well as column-chromatographed or highly clarified samples. In the samples prefixed with glutaraldehyde, the aggregates were also observed. Moreover, similar aggregates were seen in denatured actin samples. Hence it is concluded that these aggregates of actin are artefact products due to the treatment with uranyl acetate used for negative staining.

Actins↗
PubMed1983

Calmodulin antagonists stimulate renin release from isolated rat glomeruli.

Effects of calmodulin antagonists on renin release from isolated rat glomeruli were examined. The calmodulin antagonists used were N-(6-aminohexyl)-5-chloro-naphthalene-1-sulfonamide (W-7), triflupromazine and trifluoperazine. These drugs induced renin release from isolated glomeruli in a dose-dependent manner. The threshold concentration for renin release in the calcium-containing medium was 50 microM for W-7, 5 microM for triflupromazine and 2 microM for trifluoperazine respectively. The threshold concentrations were 2-5 times less in the calcium-free medium. The maximum levels of renin release by the three antagonists were similar in both calcium-containing and calcium-free media. In the absence of these antagonists, the basal rate of renin release in the calcium-free medium was markedly higher than in the calcium-containing medium. These results suggest that the calcium-calmodulin system inhibits renin release and that renin release is regulated by a mechanism different from the calcium-stimulated exocytotic mechanism by which many hormones are released.

1-Methyl-3-isobutylxanthine↗
PubMed1983

The inactive to active renin ratio in the kidneys and the plasma in diabetic nephropathy.

We examined the inactive to active renin ratio in the renin granules of the cadaver kidneys and the plasma in patients with diabetic nephropathy. The inactive renin in the break-through fraction when the plasma or the renin from the renin granules was put into a pepstatin column was determined. The inactive renin in this fraction was activated by trypsin. Concerning plasma, the inactive to active renin ratio was 90 in the patients and 9 in the normal subjects. On the other hand, this ratio was 0.29 in the patients' kidneys and 0.28 in the control kidneys. These results suggest that the increase of the inactive to active renin ratio in plasma of diabetic nephropathy does not result from the change of the renin storage in the kidneys.

Blood Proteins↗
PubMed1983

Mass screening of urea cycle diseases: a new mass screening method of hyperornithinemia by using two coupling enzymes.

We devised a new microfluorometric mass screening method for determining ornithine in only one blood disc of 3 mm in diameter (blood of 2-3 microliters) by use of two coupling enzymes, ornithine aminotransferase and delta'-pyrroline-5-carboxylate reductase. We could apply this method to some cases of gyrate atrophy of the choroid and retina. Our method can be applied in range of 0 to 12-16 nmoles or about 54.8 mg% or about 4 mM ornithine in blood. Ornithine values by our method were well correlated with those by an amino acid analyser.

Amino Acid Metabolism, Inborn Errors↗
PubMed1983

A new mass screening method for determining UDP-galactose in blood.

We devised a new microfluorometric mass screening method for determining UDP-galactose by using only one blood disc of 3 mm in diameter. This method contains two coupling enzymes of UDP-galactose-4-epimerase and UDP-glucose dehydrogenase, and conversion of NAD to NADH. The assay ranges are 0 to 1 mM or 0 to 0.2 mM UDP-galactose in blood. UDP-galactose contents were determined in galactosemia of epimerase-, transferase- and kinase-deficiencies, and several cases with high or low Paigen's values.

Galactosemias↗
PubMed1983

The existence of inactive (trypsin-activated) renin in dog plasma and renin granules from the kidney.

Trypsin-activated renin (inactive renin) was detected in the break-through fraction when dog plasma or renin extracted from renin granules (stored renin) was applied to a pepstatin column, respectively. The appearance of the renin activity by trypsin treatment was not due to acid protease. Production of angiotensin I from homologous renin substrate by the trypsin-activated renin was proportional to the time of incubation. The trypsin-activated renin had an affinity for the pepstatin column. The maximum amount of trypsin-activated renin was obtained with incubation for 15 min at 37 degrees C at 1000 micrograms/ml in plasma or at 100 micrograms/ml in case of stored renin. The ratio of inactive to active renin was calculated to be 1.6 or 0.002 in plasma or stored renin, respectively, under conditions of a standard sodium diet.

Animals↗