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Biomedical subjects

K Yasuhira

Publications and source records attributed to K Yasuhira.

14 recordsLinked to original sources
PubMed1979

Identification of benzo(a)pyrene metabolites by gas chromatograph-mass spectrometer.

A gas chromatograph-mass spectrometer was used in an attempt to achieve rapid separation and accurate identification of benzo(a)pyrene and its synthesized derivatives. All derivatives, after being trimethylsilylated, were developed on Dexsil-300 and OV-1 columns. The seven diols and four stereoisomeric 7,8,9,10-tetraols studied were separated successfully. The separation of the 12 phenols was unsatisfactory; 8- and 11-isomers appeared separately but the other 10 isomers made 3 peaks on the OV-1 column. Among the five derivatives reported to be present in animal tissues, 6-, 7-, and 9-phenols were separated, but 1- and 3-phenols were fused on the Dexsil-300 column. Quinones were converted to related dihydroxyl derivatives under silylation. The chromatographic separation of four of the six dihydroxyl derivatives was successful on the OV-1 column, but the 6,12- and 7,10-isomers remained in a single peak. The two diol-epoxides were unstable under silylation and therefore were detected by their breakdown products, 7,8,9-trihydroxy-7,8-dihydrobenzo(a)pyrene and tetraols. Data are listed on the mass spectra and retention times of all benzo(a)pyrene derivatives studied.

Benzopyrenes↗
PubMed1978

Two E-rosette-forming lymphoid cell lines.

Two E-rosette (spontaneous rosette with sheep red blood cells)-forming lymphoid cell lines were established. One (HPB-ALL) was derived from a young male Japanese patient with acute lymphoblastic leukemia (ALL), and the other (HPB-MLT) was from a 62-year-old female Japanese patient with a leukemic T-lymphoid malignancy. Formation of E rosettes, absence of any immunoglobulin determinants, absence of EBNA (Epstein-Barr virus associated nuclear antigen) and very limited stimulating ability in mixed lymphocyte culture, were characteristics mostly identical with those of so far established T-cell-derived lymphoid cell lines, MOLT, CCRF-CEM, CCRF-HS-B2, RPMI-8402 and JM. Only HPB-MLT, however, has been derived from an aged patient with T-lymphoid malignancy.

Adolescent↗
PubMed1978

Delayed hypersensitivity in mice induced by intravenous sensitization with sheep erythrocytes: evidence for tuberculin type delayed hypersensitivity of the reaction.

Delayed hypersensitivity (DH) reaction can be induced in mice by intravenous sensitization with sheep erythrocytes (SRBC). However, as the sensitizing procedure is quite different from a usual mode of sensitization for DH using complete Freund's adjuvant (FCA), the nature of this reaction has been a matter of controversy. In an attempt to characterize this reaction, we placed special interest on two possibilities regarding the nature of this reaction; Jones-Mote reaction or tuberculin type DH. From the kinetics study on the DH after challenge, the DH reaction to SRBC in mice by intravenous sensitization was clearly distinguished from the Arthus reaction. The dose-response pattern of this reaction also suggested that the contribution of Arthus reactivity to delayed reactivity was negligible. Cell reconstitution experiments revealed this DH to be quantitatively thymus cell dependent. Furthermore, this DH required macrophages at its manifestation stage, and appearance of basophil infiltration at the lesion was absent. In addition, strain difference and ageing of host mice influenced the DH reaction in exactly the same fashion in which these factors influence the tuberculin type-DH induced by subcutaneous sensitization with methylated human serum albumin (MHSA) in FCA. Taken collectively, it was concluded that this DH reaction can be categorized as the tuberculin type.

Aging↗
PubMed1975

Chromatographic analyses of 3-methylcholanthrene metabolism in adult and fetal mice and the occurrence of conjugating enzymes in the fetus.

Adult pregnant mice were given i.v. injections of (3H)3-methylcholanthrene (20 muCi in 1.1 mug/mouse) or (14C)3-methylcholanthrene (1.0 muCi in 48 mug/mouse). Ethanol extracts of their tissues were chromatographed on Sephadex LH-20. Three groups of 3-methylcholanthrene metabolites were obtained: one group as yet unidentified, one containing the hydrocarbon and hydroxylated derivatives, and a third consisting of conjugated metabolites from the treated adult mice and their fetuses. The conjugated metabolites in tissue and in bile were separated into two fractions; one was acted on by beta-glucuronidase and to a lesser extent by arylsulfatase, and the other was resistant to these enzymes but completely susceptible to acid hydrolysis. The hydrolysis resulted in altered chromatographic behavior characteristic of the hydroxy compounds, which also appear in tissue. The enzyme-resistant conjugates were predominant in brain, muscle, and lung, and the enzyme-labile conjugates were predominant in the kidney, liver, and bile of adult mice. These conjugated metabolites were also demonstrated in fetal mice; some appeared in the fetus as early as the thirteenth day of gestation, the most immature fetus so far examined. The resistant group was predominant in the early developmental stages of the fetus and the susceptible group was increased in the excretory organs such as the kidney, liver, and contents of the intestinal tract as the fetuses approached term. transplacental transfer of conjugated metabolites from the mother to the fetus did not take place, although the parent 3-methylcholanthrene and its nonconjugated metabolites were transferred. We therefore assume that drug-metabolizing enzymes, including hydroxylases and conjugases, are active in the fetal mouse tissues as well as in the adult.

Animals↗
PubMed1975

Chromatographic separation of autofluorescent and quenching substances from the hydrocarbon in tissue.

In spite of the recent progress in fluorometry, the measurement of carcinogenic hydrocarbons in tissue has been carried out with insufficient accuracy because of the presence of substances in the tissue interfering with fluorometry. Such substances, autofluorescent and quenching substances, were removed from ethanol extracts of the tissue by Sephadex LH-20 column chromatography. By elution of the column with ethanol, the interfering substances appeared in fractions of the void volume for 3-methylcholanthrene chromatography. In addition, the excitation wavelength for autofluorescent substances was found to be far from that for 3-methylcholanthrene, for which the excitation was at 300 nm and the luminescence was measured at 400 nm. Chromatographic separation of 3-methylcholanthrene and its metabolites in the bile and veces obtained from rats was done and only one peak consisting of conjugated metabolites was found on the chromatogram of the bile, though three peaks consisting respectively of the parent hydrocarbon with some metabolites, nonconjugated metabolites, and conjugated metabolites were observed in the feces. Total amounts of 3-methylcholanthrene and its metabolites, though the majority of the fluorescent substances were the parent hydrocarbon, in the lung and other organs were measured at various intervals after an intrabronchial application of 1 or 5 mg of 3-methylcholanthrene in Freund's incomplete adjuvant to rats. Preservation of the hydrocarbons in the treated lung was confirmed and this was considered to take part in the enhanced occurrence of epidermoid tumors in the lung.

Administration, Intranasal↗
PubMed1975

Nacroautoradiographic assays in pregnant mice and their fetuses given N-acetyl-9-[14C]-2-aminofluorene and p-[14C]-dimethylaminoazobenzene.

The distribution of radioactivity from N-acetyl-9-[114C]-2-aminofluorene and p-[14C]-dimethylaminoazobenzene administered i.v. or p.o. to 18-day-pregnant mice was observed by means of autoradiography of longitudinal section of the whole mouse. Radioactive substances derived from these carcinogens passed through the placenta and were distributed in the fetal organs including the kidney and intestine. Column, thin-layer, and paper chromatography revealed the presence, in while fetuses as well as in maternal livers, of N-acety-9-[14C]-2-aminofluorene. N-hydroxy-N-acetyl-9-[14C]-2-aminofluorene, ring-hydroxy-N-acetyl-9-[14C]-2-aminofluorene, and p-[14C]-dimethylaminoazobenzene. These results establish that N-acetyl-9-[14C]-2-aminofluorene and [14C]-p-dimethylaminoazobenzene are transported, metabolized, and excreted in the mouse fetus.

2-Acetylaminofluorene↗