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Biomedical subjects

M Bando

Publications and source records attributed to M Bando.

At least 109 records · Page 6Linked to original sources
PubMed1986

Scavenging of chlorpromazine cation radical by ascorbic acid or glutathione.

The report presented here demonstrates that scavenging of chlorpromazine cation radical (an absorption maximum = 530 nm) by ascorbic acid or glutathione can be kinetically and stoichiometrically analyzed at pH 1.5 but not at pH 3.0 and 6.0 using a conventional absorption spectrophotometer. The cation radical decays spontaneously about 10 and 200 times faster at pH 3.0 and 6.0, respectively, than at pH 1.5. At pH 1.5, ascorbic acid scavenges the cation radical faster than glutathione does, and the following different scavenging mechanisms are postulated from the above kinetic and stoichiometric analysis. The reaction of the cation radical with ascorbic acid is second order. The ascorbic acid free radical, which decays mainly by dismutation, is generated by the bimolecular reaction. In the case of glutathione, on the other hand, about 70% of the scavenged cation radical disappears through free radical chain reactions that glutathione thiol anion and glutathione free radical probably initiate. The remaining (about 30%) disappears by conjugation with glutathione. It may be due to relative nonreactivity of ascorbic acid free radical that free radical chain reactions, found commonly in radical chemistry, do not occur in the scavenging reaction by ascorbic acid. Based on the above results, the physiological scavenging mechanisms of the cation radical by the two reducing substances are discussed briefly.

Ascorbic Acid↗
PubMed1986

Mechanism of repetition in transcortical sensory aphasia.

A typical case of transcortical sensory aphasia (TSA) is presented, in which the Wada test suggests that it is the right hemisphere which enables the patient to repeat orally. It is supposed that one of the mechanisms of preserved repetition in TSA is linked to an exceptional ability for repetition of the right hemisphere, which may help to explain why cases of TSA are so rare.

Aged↗
PubMed1985

Calcium-induced lens protein aggregation accelerated by reactive oxygen species photosensitized in the presence of hydroxykynurenines.

Photo-oxidation with 3-OH L-kynurenine O-beta-glucoside or 3-OH L-kynurenine accelerates the aggregation of water-soluble protein in the rat lens due to the presence of calcium ion. The present report demonstrates that hydrogen peroxide and superoxide anion mediate a large part of the photodynamic acceleration with hydroxykynurenine compounds. In addition, 3-OH L-kynurenine O-beta-glucoside seems to photosensitize more of the two reactive oxygen species than 3-OH L-kynurenine. The findings are discussed together with other photodynamic effects of hydroxykynurenine compounds.

Animals↗
PubMed1985

Fluorescence/Raman intensity ratio for monitoring the pathologic state of human lens.

The authors have put quantitation of human lens fluorescence on a rational basis by using the accompanying Raman signal from lens protein as a normalization factor. The intensity ratio, Fluorescence/Raman (F/R), may be used to compare lenses of different ages when the exciting wavelength is long enough to give a measurable Raman signal. In younger lenses excited at 457.9 or 514.5 nm, the F/R shows a log increase with age. Older lenses, above 60 years of age, excited at 647.1 nm give a steeply rising sigmoid curve. In developing this procedure, the authors found that for each lens there is a characteristic wavelength that is called the critical wavelength (lambda critical). At wavelengths longer than lambda critical the Raman signal appears in the absence of a broad fluorescence peak; at shorter wavelengths the fluorescence intensity increases enough to overwhelm the Raman signal. For normal lenses, clear and not heavily pigmented, the lambda critical is age dependent, giving a curve that is a flattened sigmoid approximating a straight line.

Adolescent↗
PubMed1984

Agonadism with positive H-Y antigen.

A 30-year-old phenotypic female was investigated because of absence of the vagina. Her serum gonadotropins were elevated while testosterone was in the normal range for females. Stimulation with human chorionic gonadotropin (hCG) gave no response of testosterone. No uterus, Fallopian tubes, Wolffian derivatives, or the gonads were found at laparotomy. Chromosome analysis showed a 46,XY karyotype. The expression of the H-Y antigen was positive. The results suggest that testicular degeneration in agonadism is not caused by a defective H-Y antigen.

Adult↗
PubMed1984

Fluorophors and chromophors from rat lens crystallins in UV with hydroxykynurenine.

Isolated alpha-, beta-, and gamma-crystallins from young rat lenses were incubated in solution for 16 hr with 3-hydroxykynurenine under ultraviolet (366 nm) light. Controls included: incubation without light, without kynurenine, and with 2-mercaptoethanol. These procedures generated several chromophors (with absorption maxima or shoulders at 340, 370, and 470 nm) and fluorophors (with excitation/emission at 407/515, 458/550, 515/555, 647/664, and 647/740 nm). The formation of these pigments was inhibited by 2-mercaptoethanol. The findings are discussed in relation to the chromophors and fluorophors found in aged and brunescent human lenses.

Animals↗