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Biomedical subjects

T Kishi

Publications and source records attributed to T Kishi.

At least 109 records · Page 6Linked to original sources
PubMed1993

[Ubiquinones].

Recent topics on the biochemical and clinical aspects of ubiquinone are reviewed in this paper. Dallner and his colleagues have demonstrated that ubiquinone is synthesized, not only in mitochondria, but also on the endoplasmic reticulum-Golgi system of the rat liver. New clinical studies that reduction of ubiquinone levels and cardiac functions was induced by treatment with lovastatin, a HMG-CoA reductase inhibitor, have been reported by Folkers et al. According to recent findings, a greater part of ubiquinone in rat and human tissues exists as a reduced hydroquinone form of ubiquinol. On the other hand, good evidence for the antioxidative activity of ubiquinol was obtained from experiments using phosphatidylcholine liposomes and low density lipoprotein.

Animals↗
PubMed1992

A novel ubiquinone reductase activity in rat cytosol.

Ubiquinone (UQ) reductase activity which reduces UQ to ubiquinol (UQH2) in rat tissues was roughly proportional to the UQH2/total UQ ratio in respective tissues. The highest activity was found in the liver, showing the highest UQH2/total UQ ratio. A greater part of liver UQ reductase activity was located in the cytosol. Within a week, the liver UQ reductase activity decreased by 80% even at -20 degrees C. The DT-diaphorase activity was stable. UQ reductase required NADPH as the hydrogen donor and was not inhibited by a less than 1 microM concentration of dicoumarol. There was no stimulation of UQ reductase in the presence of bovine serum albumin nor in Triton X-100. Yet, both stimulated DT-diaphorase. As a result, UQ reductase appeared to be a novel NADPH-UQ oxidoreductase and responsible for the UQ redox state in liver.

Animals↗
PubMed1992

Mechanism of protein priming DNA replication of B.subtilis phage M2.

B.subtilis phage M2 uses a protein, instead of RNA, as the primer of its DNA replication. Hence this protein encoded in the phage genome is called as the primer protein (PP). At the initiation of DNA replication, a hetero dimer complex with its own DNA polymerase and the PP supposed to interact with the terminal protein (TP), which is covalently bound to the template DNA (TP-DNA). PP contained an important adhesive amino acid sequence, Arg-Gly-Asp (RGD), near the carboxyl terminal. We have recently showed that the synthetic RGD peptide inhibited the transfection of phage M2. By site-directed mutagenesis, we introduced different amino acid into the RGD site of PP. These altered PP decreased obviously the priming activity in vitro.

Bacillus Phages↗
PubMed1992

Effect of ubiquinone-10 on fluctuation of beating rhythm of cultured myocardial cell sheets.

Effects of ubiquinone-10 (UQ-10) on fluctuation of beat time intervals and on beat frequencies were investigated in cultured ventricular myocytes obtained from mouse fetuses and quail embryos. Fluctuation rates of beat time intervals of mouse and quail myocardial cell sheets growing in the culture medium supplemented with 10% fetal bovine serum increased significantly to 1.2-fold and twice, respectively by removing serum from the medium. Beat frequencies of the cell sheets also significantly decreased simultaneously with the increase in the fluctuation rates. However, such changes of beating states were almost completely recovered within 10 min by addition of 100 microM UQ-10 as an isotonic lecithin emulsion to the medium. The addition of UQ-10 also significantly increased intracellular ATP content in the cell sheets concomitantly. These results suggested that UQ-10 circulating in serum may participate in the maintenance of regular and rhythmical beating of myocardial cells, presumably through stimulating intracellular ATP generating systems.

Adenosine Triphosphate↗
PubMed1992

Drunken driving and breath alcohol test at the scene of violence in Japan.

Road Traffic Law prescribes that no person shall drive any vehicle under the influence of intoxicating liquor. Actually, determination of "influence of alcohol" is based on the standard set by the Cabinet Order that alcohol level exceeds 0.5 mg/ml of blood or 0.25 mg/l of expiration. In 1988, number of traffic accidents by drunken driving is 4,808 cases. Among the accidents by drunken driving the rate of fatal causes is 12%. During about last ten years, both of accidents and fatal cases by drunken driving have been decreasing in number, on the other hand, charged or cited number of violation involved "driving under the influence of alcohol" has been increasing. This fact indicates that the concept of seriousness of driving after heavy drinking has been diffused over Japanese nation, but there is still a tendency among drivers to consider the effect of alcohol on driving operation to be negligible when light drinking. In a sobriety checkpoint, alcohol field test are carried out on breath to screen out impaired driver. The most common device used in Japan is an alcohol detector tube, in which cerite particles coated with chromate are packed. The scale on the detector tube is marked to show a value that is lower by 20% than the actual value concerning its inaccuracy. In our study on accuracy of the alcohol detector tube using samples containing approximately 0.25 mg/l of alcohol, which is legal critical level of alcohol impairment, coefficients of variation were 1.50 to 5.45% and deviations from the analytical results by gas chromatography were 18.2 to 19.5%.

Accidents, Traffic↗
PubMed1991

Sandwich enzyme immunoassay for rat transferrin with two monoclonal antibodies and its application.

The development of a sandwich enzyme immunoassay for rat transferrin with two monoclonal antibodies is described. Microtiter plates coated with one monoclonal antibody (15C2H3) were used, and captured transferrin was estimated with a horseradish peroxidase-conjugated Fab' fragment of another monoclonal antibody (22A06D2). In this assay, the measurable range is 5-150 ng/ml and the coefficients of variation within and between the assay series are 1.2-5.0 and 3.3-6.0%, respectively. Recovery was 101 +/- 9.7% when purified rat transferrin was added to rat plasma. No cross-reactivity with bovine, human, or mouse transferrin was shown. This assay for rat transferrin is a highly specific, sensitive, and expeditious method which may allow routine analysis of rat transferrin in blood or culture supernatants of rat hepatocytes.

Animals↗
PubMed1991

Mannose-resistant adhesion of motile Aeromonas to INT407 cells and the differences among isolates from humans, food and water.

Aeromonas has been recognized as an important enteropathogen, but factors related to its virulence have not been clarified. For most enteric pathogens, attachment is a prerequisite for infection and for the effective delivery of toxins to the intestinal epithelial cells. We examined a total of 273 strains isolated from stool, food and environmental specimens by an assay for mannose-resistant adhesion to INT407 cells in vitro. Seventeen of the 102 faecal isolates were adhesive strains with more than 10 bacteria adhering per cell, while only 2 of the 118 isolates from foods and river water adhered to the cells (P less than 0.001). It is possible that the adhesion might serve as a marker for discrimination between the pathogenic and nonpathogenic isolates. The 8 highly adhesive strains with more than 20 adhering organisms per cell were scrutinized for the mechanism of adhesion. No correlation was apparent between the adhesion to INT407 cells and hydrophobicity. It was noted that fucose inhibited the adhesion of four strains as well as haemagglutination by them. Electronmicroscopic studies showed the presence of flexible and curvilinear fimbriae in only 2 of the 8 highly adhesive strains.

Aeromonas↗
PubMed1991

Absolute structure-cytotoxic activity relationships of steganacin congeners and analogues.

The cytotoxic activities of optically pure and racemic steganacin congeners and analogues against KB cells in culture and the inhibitor activity of cilia regeneration in Tetrahymena were studied with regard to absolute and relative configurations. The stereochemical requirements of dibenzocyclooctadiene lignan lactones for activity were clarified.

4-Butyrolactone↗
PubMed1991

New perylenequinones from Shiraia bambusicola.

Two new perylenequinones, named hypocrellin B and C, together with the known hypocrellin A were isolated from the stromatal tissues of Shiraia bambusicola. The structures of these compounds, including the absolute stereochemistry, were determined.

Ascomycota↗
PubMed1991

Fracture behavior of dental composite resins.

Fracture toughness (KIC), critical stress intensity factor, and bending strength of 3 types of commercially available dental composite resins (macrofilled, hybrid and microfilled type) were determined using three point bend specimens. Acoustic Emission (AE), which is the generation of elastic wave due to the release of energy from the localized sources in material, was also detected during the fracture toughness test. Fracture surfaces were examined by scanning electron microscope. The fracture toughness values, AE patterns, and the nature of fracture surface were analyzed to understand fracture behavior of dental composite resins and fracture mechanism for each dental composite resin are proposed.

Acoustics↗
PubMed1991

Inhibition of mitochondrial respiratory chain by alkylthiolated 2,3-dicyano-1,4-benzoquinones.

A series of alkylthiolated 2,3-dicyano-1,4-benzoquinones was synthesized and tested for the effects on the respiratory chain in beef heart mitochondria as an antimetabolite of ubiquinones (coenzyme Q). It was proved that these analogs are among the best inhibitors of both succinate oxidase and NADH oxidase systems. The introduction of a 2,3-dicyano group to the quinone ring was found to be more favorable for inhibitory activity than 2,3-dimethoxy, 2,3-dimethyl groups and bicyclic quinones such as 2,3-ethylenedioxy-1,4-benzoquinones and 1,4-naphthoquinones. The inhibitory activity was minimally sensitive to the length of the alkylthio side-chain. On the other hand, the difference spectra of reduced minus oxidized forms of cytochromes were investigated to identify the inhibitory site, suggesting that alkylthiolated 2,3-dicyano-1,4-benzoquinones inhibit at sites between the substrates (succinate and NADH) and cytochrome b, and at the site after cytochrome a + a3 in the respiratory chain.

Animals↗
PubMed1990

DNA breaks and repair in the mouse leukemia L1210 cells exposed to three different types of interstrand DNA cross-linkers.

DNA breaks and repair in mouse leukemia L1210 cells treated with 3 different types of cross-linkers, mitomycin C (MMC), 1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitroso ure a hydrochloride (ACNU) and SN-07 (a macromolecular antibiotic), were studied. Measured in D37 values, MMC gave the highest number of cross-links per lethal 'hit' directly after the 1-h treatment in the alkaline elution assay, followed by ACNU and SN-07. A good dose-response increase in induced interstrand DNA cross-linking frequency was observed in cells treated with 2.5-10 micrograms/ml MMC and with 10-100 micrograms/ml ACNU for 1 h with and without 24-h post-incubation. After 6-h post-incubation, the highest frequency of cross-linking was observed in cells treated with 2.5 micrograms/ml MMC and 30 micrograms/ml ACNU, while cross-link production continued in the cells treated with SN-07 for 12-h post-incubation. No significant increase in DNA breaks was observed in cells treated with MMC throughout 24-h post-incubation. The highest frequency of single-strand DNA breaks in cells treated with ACNU was observed immediately after the treatment and they disappeared after 6-h post-incubation. After 24-h post-incubation, a marked enhancement of the DNA breaks was observed in cells treated with SN-07 and the cells contained double-strand DNA breaks also. RNA synthesis was not affected in the cells treated with 10 micrograms/ml MMC and slightly inhibited to 70% of control in those treated with 100 micrograms/ml ACNU, while DNA synthesis in both cells was significantly inhibited after 24-h post-incubation. By contrast, both RNA and DNA synthesis were completely inhibited in cells treated with 8.0 micrograms/ml SN-07.

Animals↗
PubMed1990

Screening of aquatic samples for Vibrio cholerae serotype O1 by a dot-blot method and a latex agglutination test.

A dot-blot, enzyme-linked immunosorbent method and a latex agglutination test were studied for their abilities to detect Vibrio cholerae serotype O1 in aquatic samples by testing artificially contaminated water as well as samples from natural potential sources. Water samples were preenriched with alkaline peptone and then enriched with Monsur peptone water. For the dot-blot test, enriched cultures of organisms in a small portion of the Monsur peptone water were transferred to a polyvinylidene difluoride membrane with a microfiltration apparatus. The enzyme-linked immunosorbent assay was performed by using biotin-labeled antibodies and avidin-biotin-peroxidase complex; brown dots developed in the wells that contained serotype O1 vibrios. Latex agglutination tests were performed by mixing 1 drop of the culture in Monsur with 1 drop of reagent coated with monoclonal antibody specific for antigen A. The sensitivities and specificities of the methods were compared with those of the colony-blot method, which identified individual colonies of V. cholerae O1 in mixed bacterial cultures on isolation media. Our results indicate that the dot-blot method is as sensitive as the colony-blot method and is useful for screening for V. cholerae serotype O1 even in specimens that are heavily contaminated with non-O1 vibrios.

Humans↗
PubMed1990

Inhibition of mitochondrial respiratory chain by arylthiolated 2,3-ethylenedioxy-1,4-benzoquinones.

A series of arylthiolated 2,3-ethylenedioxy-1,4-benzoquinones as a coenzyme Q (CoQ) antagonist was tested for inhibition of succinate oxidase and reduced nicotinamide adenine dinucleotide (NADH) oxidase systems in the mitochondrial respiratory chain. The following characteristics were revealed: (1) 2,3-ethylenedioxy, 5-arylthio and 5,6-diarylthio groups were confirmed to be favorable for inhibition of both systems; (2) these analogs were more effective in the succinate oxidase system than in the NADH oxidase system; (3) 4' substituents on the benzene side ring had little effect on inhibitory activity; (4) the acting sites of these analogs had no strict stereospecificity. The reduced minus oxidized difference spectra revealed that these analogs inhibited the succinate oxidase system at the site between succinate and CoQ, and the NADH oxidase system at the site after cytochrome a + a3, suggesting these analogs might act as antagonists of CoQ in the succinate oxidase system. However, 5-(4'-nitrophenylthio)-2,3-ethylenedioxy-1,4-benzoquinone (If) strongly inhibited only the succinate oxidase system at the site after cytochrome a + a3.

Animals↗
PubMed1990

Induction of tissue factor by interleukin-2 in acute myelogenous leukemia (AML) cells.

We investigated the induction of tissue factor by lymphokines in human monoblastic leukemia cell lines (U937) and leukemic cells from AML (acute myelogenous leukemia) patients. After incubation for 24 h, IL-2 enhanced the intracellular tissue factor 15-fold with U937 cells, and GM-CSF enhanced it 6-fold. In contrast, other lymphokines, such as IL-1-alpha, IL-1-beta, IL-3, IL-4 and G-CSF, did not affect the activity of tissue factor. The leukemic blasts, depleted of T-lymphocytes, taken from five out of 16 AML patients showed a 2.5-14-fold increase in the activity of tissue factor per cell following incubation with 200 u/ml of IL-2 for 72 h. The IL-2 induced tissue factor activity more markedly than GM-CSF. Tissue factor stimulation by IL-2 did not correlate with the expression of the IL-2 receptor, Tac, but correlated well with FAB classification of AML cells. IL-2 responders were found in M4 and M5 subtypes only, but not all M4/M5 leukemias responded to IL-2. These findings indicate that IL-2 can mediate the tissue factor induction in the monocytic type of AML and the effect is not mediated by Tac receptors. This may shed a new light on our understanding of hypercoagulability in acute monoblastic leukemia.

Cytokines↗
PubMed1990

[Antianaphylactic components of Asarum forbsii Maxin].

From the ethyl acetate extract of Asarum forbesii Maxin, four new constituents, asarumin A(I), B(II), C(III) and D(IV), were isolated along with elemicin (V), trans-asarone(VI) and linoleic acid(VII). The structures of the new compounds were elucidated as methyl 3 S-benzoyloxy-2 S-hydroxy-2-isopropylbutyrate for I, methyl 2 R-benzoyloxyisopentanoate for II, methyl 2 R-trans-cinnamoyloxyisopentanoate for III and methyl 2 R-piperonyloyloxyisopentanoate for IV. Compounds I, II, III and VII showed weak inhibition of PCA in rats, but the other compounds were inactive.

Animals↗