Renal tubular acidosis.
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Acidosis, Renal Tubular↗
Biomedical subjects
D Ban
Publications and source records attributed to D Ban.
Temporal changes in islet polymerized and depolymerized tubulin during biphasic insulin release.
In the present study, a colchicine binding assay was used to measure changes in islet polymerized and depolymerized tubulin at intervals characterizing the biphasic pattern of glucose-induced insulin release i.e., 2.5, 5.5, 10.5, and 30.5 min. At 2.5 min during the rapid onset of insulin release, a significant increase from 24% to 33% in polymerized tubulin content was observed. This increase in polymerized tubulin was followed by a reduction that temporally correlated with the disappearance of first phase release. Second phase release was also associated with a shift in equilibrium favoring tubulin polymerization at longer incubation periods. The effect of cytochalasin B on the equilibrium between polymerized and depolymerized tubulin was evaluated at a submaximal glucose concentration of 16.5 mM. Under these conditions, cytochalasin B increased polymerized tubulin content in a manner that parallels its enhancing effect on insulin release. These results indicate that the rapid events associated with the biphasic pattern of insulin release are temporally correlated with changes in polymerized tubulin.
Animals↗
The sustained antihypertensive effect of chronic cerebroventricular infusion of angiotensin antagonist in spontaneously hypertensive rats.
The angiotensin antagonist [Sar1-Ile8]angiotensin II was infused into the lateral ventricles of mature spontaneously hypertensive and normotensive Wistar-Kyoto rats. Infusions were maintained at rats of 1200 ng/h for 6 days, and blood pressure was measured daily in the unanesthetized state. Blood pressure reduction occurred promptly and only in the hypertensive animals. This antihypertensive effect persisted for several days after discontinuation of the infusion. In contrast, iv infusion of the angiotensin antagonist at comparable doses failed to alter blood pressure in any significant fashion. These data suggest that the brain isorenin system participates in the maintenance of hypertension in the spontaneously hypertensive rat.
1-Sarcosine-8-Isoleucine Angiotensin II↗
Characterization of two forms of asparaginase in Saccharomyces cerevisiae.
Saccharomyces cerevisiae X2180-1A synthesizes two forms of asparaginase: L-asparaginase I, an internal constitutive enzyme, and asparaginase II, an external enzyme which is secreted in response to nitrogen starvation. The two enzymes are biochemically and genetically distinct. The structural gene for asparaginase I (asp 1) is closely linked to the trp 4 gene on chromosome IV. The gene controlling the synthesis of asparaginase II is not linked to either the trp 4 or asp 1 genes. The rate of biosynthesis of asparaginase II is unaltered in yeast strains carrying the structural gene mutation for asparaginase I. Asparaginase II has been purified approximately 300-fold from crude extracts of Saccharomyces by heat and pH treatment, ethanol fractionation, ammonium sulfate fractionation followed by Sephadex G-25 chromatography, and DEAE-cellulose chromatography. Multiple activity peaks were obtained which, upon gas chromatographic analysis, exhibit varying mannose to protein ratios. Asparaginase I has been purified approximately 100-fold from crude extracts of Saccharomyces by protamine sulfate treatment, ammonium sulfate fractionation, gel permeation chromatography, and DEAE-cellulose chromatography. No carbohydrate component was observed upon gas chromatographic analysis. Comparative kinetic and analytic studies show the two enzymes have little in common except their ability to hydrolyze L-asparagine to L-aspartic acid and ammonia.
Asparaginase↗