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Biomedical subjects

Y Asada

Publications and source records attributed to Y Asada.

At least 271 records · Page 15Linked to original sources
PubMed1985

Auto-oxidative damage in cement dermatitis.

Oxygen intermediates (OIs) generated by stimulated polymorphonuclear leukocytes (PMNs) are known to induce auto-oxidative tissue damage at the site of inflammation. PMNs from five patients with severe and chronic cement dermatitis generated markedly increased levels of OIs. However, only a slight increase in OI generation by PMNs was observed in cement workers without cement dermatitis. Dapsone, which has recently been shown to decrease OI levels, was found to be clinically effective in the treatment of cement dermatitis in these five patients. After treatment, a significant decrease in OI generation was observed in all patients studied. In skin tissues from the cement workers without cement dermatitis, enhanced superoxide-dismutase (SOD) activities as well as increased OI generation by PMNs were noted. In spite of the greatly increased OI generation by PMNs, the SOD activities in the patients were comparable to those in healthy controls. These findings suggest that the severe skin manifestations in patients with cement dermatitis can partly be explained by a defective capacity for enhancing SOD activity which removes increased PMN-derived OIs and thus prevents subsequent tissue injury by OIs at the site of inflammation.

Adult↗
PubMed1985

Genotoxicity of a variety of pyrrolizidine alkaloids in the hepatocyte primary culture-DNA repair test using rat, mouse, and hamster hepatocytes.

Seventeen pyrrolizidine alkaloids were studied with the hepatocyte primary culture-DNA repair test using rat hepatocytes. DNA repair synthesis was elicited by 15 alkaloids, including 11 of unknown carcinogenicity, i.e., senecionine, seneciphylline, jacobine, epoxyseneciphylline, senecicannabine, acetylfukinotoxin, syneilesine, dihydroclivorine, ligularidine, neoligularidine, and ligularizine. The positive results with these alkaloids of unknown carcinogenicity suggest that they are possibly genotoxic carcinogens. The two pyrrolizidine alkaloids that did not elicit DNA repair were retronecine which lacks a necic acid component and ligularinine which lacks the unsaturated double bond at the 1,2-position of the pyrrolizidine ring. Five pyrrolizidine alkaloids, retronecine, monocrotaline, seneciphylline, senkirkine, and clivorine, were also tested in the DNA repair test with hamster or mouse hepatocytes. These alkaloids, except retronecine, showed a positive response in the test with hamster hepatocytes, but in the test with mouse hepatocytes clivorine in addition to retronecine was also negative. The results indicate a species difference in liver bioactivation of pyrrolizidine alkaloids, implying that there could be species differences in their carcinogenic activities.

Animals↗
PubMed1984

Stereochemistry of ornithine decarboxylase reaction.

To determine the steric course of the reaction of bacterial ornithine decarboxylase [EC 4.1.1.17], we have carried out the decarboxylation of L-ornithine in 2H2O and that of DL-[2-2H]ornithine in H2O, and obtained putrescine bearing a single deuterium atom in the C-1 position. The stereochemistry of [1-2H]putrescine was established by conversion to 1-(2-pyrrolidinyl)-2-propanone with acetoacetate and the pro-S hydrogen-specific diamine oxidase from pea seedlings. Analysis of deuterium content by gas chromatography-mass spectrometry showed that the deuterium label was fully retained during the conversion of [1-2H]putrescine produced by the decarboxylation of L-ornithine in 2H2O to 1-(2-pyrrolidinyl)-2-propanone, in contrast with the considerable loss of label from [1-2H]putrescine which was produced by the decarboxylation of DL-[2-2H]ornithine in H2O. The extent of loss of the deuterium label was in good agreement with the estimated value based on the isotope effect in the diamine oxidase reaction. These results indicate that the introduced deuterium (or hydrogen) is in the pro-R position at C-1 of putrescine, and consequently the ornithine decarboxylase reaction proceeds with retention of configuration.

Chemical Phenomena↗
PubMed1984

Naturally occurring T lymphocytotoxic antibody in viral and related skin diseases.

The naturally occurring T lymphocytotoxic antibodies in patients with viral and related skin diseases were investigated and compared with those of systemic lupus erythematosus (SLE). The incidences of T lymphocytotoxic antibodies in exanthema suspected of viral infection, infectious mononucleosis, rubella and pityriasis rosea were 28%, 44%, 8% and 28% respectively. Sera from patients with herpes zoster and erythema infectiosum did not show positivity. Incidence in SLE sera as positive control was 82%. The T lymphocytotoxic antibodies detected in skin diseases were similar in nature to those of SLE patients, but were transient and lower in titer than those of SLE.

Antibodies, Viral↗
PubMed1983

Primary macroglobulinemia presenting as multiple ulcers of the legs.

Multiple ulcers developed on the lower legs of a 67-year-old man suffering from macroglobulinemia. Histological and direct immunofluorescence studies on biopsy specimens taken from the lesions revealed dilation of capillaries, deposition of large quantities of IgM in the vessels, and deposition of C3 in the vessel walls. A marked increase in blood Clq binding immune complexes was also noted. These findings suggest immune complex-induced ulceration. The fact that IgM-type cryoglobulins were positive implies that cryoglobulins derived from macroglobulins may play an important causative role in ulceration.

Aged↗
PubMed1982

Stereochemistry of proton abstraction catalyzed by lysine and ornithine omega-aminotransferases.

(6R)-L-[6-3H]Lysine and (6S)-L-[6]3H]lysine were prepared to investigate the stereochemical aspects of the reaction catalyzed by bacterial L-lysine epsilon-aminotransferase. When (6R)-L-[6-3H]lysine was used as a substrate, the tritium label was retained in the product, delta 1-piperideine-6-carboxylate. In contrast, the radioactivity from (6S)-L-[6-3H]lysine was found in the solvent. Thus, the pro-S hydrogen at the prochiral C-6 carbon of L-lysine is specifically abstracted by L-lysine epsilon-aminotransferase. The proton exchange was observed by proton nuclear magnetic resonance analysis in the reaction of bacterial L-ornithine delta-aminotransferase with L-ornithine in 2H2O. The isolated L-[5-2H]ornithine was converted to dextrorotatory 4-phthalimido[4-2H]butyrate. This indicates that L-ornithine delta-aminotransferase catalyzes the stereospecific exchange of the pro-S hydrogen at the prochiral C-5 carbon of L-ornithine with the solvent.

Binding Sites↗
PubMed1982

[Clinical evaluation of cefmetazole in the dermatologic field].

The therapeutic efficacy and safety of cefmetazole, a cephamycin-derived antibiotic in an injectable form were evaluated in patients with pyogenic infection in the dermatological field. Especially, it was found to be extremely effective for the skin diseases due to staphylococci or streptococci. The results obtained were the following; marked improvement in 18 cases and moderate improvement in 34 cases out of 61 cases, attaining efficacy of 86.7%. Side effects were noted as the rise of GOT and GPT in 3 cases, which were normalized by ceasing its further administration. The MIC of cefmetazole against Staphylococcus aureus isolated out of foci was 0.39-6.25 microgram/ml, while those of CEZ, CXM and ABPC used as the controls exceeded 50 microgram/ml in some cases. It is considered thus, that cefmetazole, is superior to these other antibiotics also in terms of MIC.

Adolescent↗
PubMed1981

Stereochemistry of meso-alpha,epsilon-diaminopimelate decarboxylase reaction: the first evidence for pyridoxal 5'-phosphate dependent decarboxylation with inversion of configuration.

The stereochemistry of the decarboxylation of meso-alpha,epsilon-diaminopimelate catalyzed by meso-alpha,epsilon-diaminopimelate decarboxylase (EC 4.1.1.20) of Bacillus sphaericus was determined by stereochemical analyses of [6-2H]-L-lysine produced by the reaction in D2O. The product [6-2H]-L-lysine was converted to levorotatory methyl 5-phthalimido[5-2H]valerate by the reactions not affecting the absolute configuration of the asymmetric carbon atom. By contrast, methyl 5-phthalimido[5-2H]valerate derived from [2,6-2H2]-L-lysine, which was produced from [2,6-2H2]diaminopimelate by decarboxylation in H2O, was dextrorotatory. The authentic methyl (R)-5-phthalimido[5-2H]valerate prepared from L-glutamate with glutamate decarboxylase was levorotatory. These results indicate that the meso-alpha,epsilon-diaminopimelate decarboxylase reaction proceeds in an inversion mode. The deuterium label in [6-2H]-L-lysine was fully conserved during the conversion into pelletierine through [1-2H]cadaverine by the stereospecific diamine oxidase reaction. Thus, the enzymatic decarboxylation of meso-alpha,epsilon-diaminopimelate occurs with inversion of configuration in contrast to the other amino acid decarboxylase reported so far.

Bacillus↗
PubMed1980

CArcinogenic activity of clivorine, a pyrrolizidine alkaloid isolated from Ligularia dentata.

The carcinogenic activity of clivorine, a pyrrolizidine alkaloid isolated from Ligularia dentata, was studied in inbred ACI rats. Twelve animals in the experimental group received a 0.005% solution of clivorine in drinking water for 340 days and survived beyond 440 days after the beginning of the experiment. Of this group, 8 developed tumors in the liver; 2 developed hemangioendothelial sarcomas, and 6 developed neoplastic nodules. The hemangioendothelial sarcoma showed metastasis in the lung of one rat. No tumors were observed in the liver of the control animals.

Animals↗