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Biomedical subjects

Y Tamura

Publications and source records attributed to Y Tamura.

At least 739 records · Page 41Linked to original sources
PubMed1977

Synthetic inhibitors of trypsin, plasmin, kallikrein, thrombin, C1r-, and C1 esterase.

p-Carbethoxyphenyl episol-guanidinocaproate and p-(p'-guanidinobenzoyloxy)-phenyl derivatives were prepared, and their inhibitory effects on trypsin, plasmin, plasma kallikrein, thrombin, C1r- and C1 esterase were examined. Among the various inhibitors tested, p-nitrophenyl p'-guanidinobenzoate, N,N-dimethylamino p-(p'-guanidinobenzoyloxy)-benzoyl glycolate and N,N-dimethylamino p-(p'-guanidinobenzoyloxy)-benzilcarbonyloxy glycolate were the most effective inhibitors of trypsin, plasmin, plasma kallikrien and thrombin, and they strongly inhibited the esterolytic activities of C1r- and C1 esterase.

Complement Activating Enzymes↗
PubMed1977

Stimulation of a reconstituted, microsomal NADH oxidase system by carboquone, a quinoid anticancer chemical.

Carboquone was found to greatly stimulate the aerobic NADH oxidation in the presence of both the partially purified NADH-cytochrome b5 reductase and cytochrome b5 prepared from hepatic microsomes by acting as an electron carrier from cytochrome b5 to molecular oxygen. Other quinoid anticancer chemicals, mitomycin-C, adriamycin, and daunomycin practically failed to do so.

Animals↗
PubMed1977

Electron spin resonance study on the mode of generation of free radicals of daunomycin, adriamycin, and carboquone in NAD(P)H-microsome system.

The mode of generation of free radicals of daunomycin, adriamycin, and carboquone in the NADPH-rat liver microsome system was studied at room temperature by electron spin resonance (ESR) spectroscopy. ESR signals of all these quinoid anticancer chemicals were detected when dissolved oxygen in the reaction mixture was consumed since the radicals are easilyaut oxidizable. All the radicals had an appreciable lifetime under anaerobic conditions. However, there were differences in the mode of their generation between daunomycin and adriamycin, on the one hand, and carboquone, on the other, with respect to the lag time and the effect of the amount of chemicals, pH of the medium, kind of electron donors, NADPH and NADH, and the presence of excess of DNA. Especially, ESR signal reappeared after the first signal had decreased considerably, in the case of daunomycin and adriamycin but not in carboquone. Intact Ehrlich ascites tumor cells also gave rise to an ESR signal of adriamycin and carboquone, but the former signal was prevented from appearing in the presence of glucose.

Animals↗
PubMed1976

[Clinical study of pseudohypoparathyroidism Type I & Type II (author's transl)].

Pseudohypoparathyroidism (PHP) is a disorder characterized by renal and/or skeletal refractoriness to the effect of parathyroid hormone (PTH). In 1973, it was first proposed by Drezner et al that PHP could be divided into two types, e.g., PHP Type I and PHP Type II. PHP Type I is a disorder which fails to show the increase of urinary c-AMP and phosphaturia by the administration of PTH, but PHP Type II is that which responds to the administration of PTH with a marked rise of urinary c-AMP, but no increase of phosphate excretion, In 1974 Rodriguez et al demonstrated a patient with PHP Type II who restored normal renal responsiveness to PTH by calcium administration. Here we present two patients who fitted in the categories of PHP Type I & II, respectively, and restored normal renal responsiveness by the combined Ca-PTH administration or dibutyryl-cAMP infusion. Case I (PHP Type I) was a 31 yr old male with marked hypocalcemia and hyperphosphatemia, who showed neither increase of urinary c-AMP nor phosphate excretion in response to PTH infusion. Case II (PHP Type II), also diagnosed as Sjögren syndrome was a 22 yr old female with relatively mild hypocalcemia and hyperphosphatemia, who showed a marked rise of ordinary c-AMP, but no increase of phosphate excretion by PTH administration. Acute infusion of calcium, followed by PTH administration restored renal responsiveness to PTH in both types, though calcium infusion showed only little effects. The patient of PHP Type I received calcium gluconate and Vitamin D therapy and serum Ca improved, when PTH or DBc-AMP was given with the reappearance of PTH-like action. Thus in PHP Type I, the lack of c-AMP response to PTH, coupled with the ability of infused DBc-AMP to evoke a normal renal response suggests that the metabolic defect in this disorder may exist in hormone receptor-adenyl cyclase complex. Calcium infusion followed by PTH administration probably might evoke calcium influx and c-AMP production, resulting in the reappearance of hormone action. In PHP Type II, as c-AMP generation system is intact, the metabolic defect can be thought to exist in the rather poorly defined process beyond c-AMP generation. The combined Ca-PTH administration also restored normal renal response, probably partly due to the improved calcium environment of renal tubular cells. Though it is difficult to explain why endogenously generated c-AMP had no effect, but DBc-AMP had on reappearance of PTH-like action, it is speculated that DBc-AMP may have much more stronger effects for intracellular receptor site of c-AMP in PHP Type II. Conclusively these results clearly suggest that the nature of the metabolic defects in PHP is not a genetically determined inrreversible disorder, but rather a functional one which can be reversibly restored by special conditioning.

Adult↗
PubMed1976

The role of C1 esterase inhibitor in the activation of C1r, a subcomponent of the first component of complement from human plasma.

Clr was isolated from human serum by DEAE-cellulose column chromatography in the presence of EDTA. The isolated Clr did not hydrolyze N(alpha)-acetyl-L-arginine methyl ester, unless activated by brief treatment with trypsin [EC 3.4.21.4]. On thecolumn, the C1 esterase inhibitor activity was found to coincide with Clr but not C1s (another subcomponent of the first component) C1r was isolated from the euglobulin fraction of human serum by DEAE-cellulose column chromatograph. On Sephadex G-200 column chromatography, Clr was eluted in the void volume, whereas Clr was eluted in a position corresponding to a molecular weight of 140,000-160,000. The results indicated that, on activation, Clr was converted to an enzyme of lower molecular weight...

Chromatography, Ion Exchange↗
PubMed1976

Purification of human plasma kallikrein and urokinase by affinity chromatography.

L-Homoarginine benzylester was coupled with Sepharose 4B and used for affinity chromatography of human plasma kallikrein [EC 3.4.21.8] and urokinase [EC 3.4.99.26]. The euglobulin fraction of human plasma was treated with disodium ethylenediamine-tetraacetate (EDTA) and activated with acetone, and then kallikrein was purified 16-fold by affinity chromatography. The yield of kallikrein activity on affinity chromatography was 53%. The purified preparation of human plasma kallikrein appeared to be homogenous on gel electrophoresis. Commercial urokinase was also purified 4.8-fold with 64% yield by affinity chromatography.

Acetone↗
PubMed1975

Thermal denaturation and regeneration of japanese-radish peroxidase.

Thermal denaturation of Japanese-radish peroxidase [EC 1.11.1.7] was investigated with respect to its spectrophotometric properties and effect on the enzymatic activity. Inactivation of the peroxidase occurred at temperatures higher than 60degrees and involved three processes, i.e., dissociation of protohemin from the holoperoxidase, a conformation change in the apperoxidase, and the modification or degradation of protohemin. The splitting process of protohemin from holoperoxidase as followed by the change in the absorption spectrum at high temperatures coincided with the degrease in the activity, and it was found to be at least biphasic. The regeneration of peroxidase on cooling to room temperature was essentially reversible at neutral pH, while at pH 5 and pH 9 these processes were irreversible. The irreversibility at acidic pH was mainly due to an irreversible change in the conformation of the apoenzyme. The difference spectrum of heat-treated apoperoxidase exhibited a denaturation blueshift with negative maxima at 287 and 294 nm, and the total protein fluorescence quantum yield. qprotein, increased by 20% compared to that of the untreated apoenzyme. On the other hand, the irreversibility at alkaline pH was largely attributable to the modification of protohemin. Apoperoxidase was more resistnat to heat denaturation but the modification or degradation of protohemin in heated enzyme was greater at alkaline pH than at acidic pH. The pyridine-ferrohemochrome spectrum of peroxidase exhibited slight shifts of the maxima of the alpha-band to shorter wavelength on heat treatment, and the paper chromatogram showed the presence of a new derivative other than protohemin. The modified product is probably (2(4)-vinyl-4(2)-hydroxyethyldeuterohemin.

Drug Stability↗
PubMed1975

Aminopeptidases and arylamidases in normal and cancer tissues in humans.

Multiforms of aminopeptidases and arylamidases in normal human liver, stomach, lung, ileum, colon, rectum, and kidney, and cancer tissue from human liver, stomach, and lung were separated by triethylaminoethyl cellulose column chromatography. The aminopeptidases and arylamidases were solubilized from human tissues by treatment with bromelain, and their column chromatograms on triethylaminoethyl-cellulose gave different patterns of multiforms of enzymes in these tissues. The fractions of enzymes separated specificities toward L-leucyl-beta-naphthylamide, L-leucinamide, L-methioninamide, L-phenylalaninamide, and L-alaninamide. The activity of aminopeptidase toward L-leucinamide and of arylamidase toward L-leucyl-beta-naphthylamide was higher in human stomach cancer tissue and lower in hepatic cancer tissue than in normal stomach and liver, respectively. In lung cancer tissue, the activity of aminopeptidase toward L-leucinamide was abnormally low, while the activity of arylamidase toward L-leucyl-beta-napthylamide was similar to that in normal lung. The substrate specificities or patterns of the multiforms of these enzymes in cancer tissue from human liver, stomach, and lung were shown to differ from those of normal liver, stomach, and lung, respectively, by triethylaminoethyl cellulose column chromatography.

Alanine↗