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Biomedical subjects

F Takeuchi

Publications and source records attributed to F Takeuchi.

At least 127 records · Page 7Linked to original sources
PubMed1985

Decrease in the reaction of DNA repair synthesis in response to nicotinamide or 3-aminobenzamide in ultraviolet irradiated systemic lupus erythematosus lymphocytes.

Systemic lupus erythematosus (SLE) lymphocytes failed to accelerate ultraviolet (UV) induced DNA repair synthesis normally observed following inhibition of poly(adenosine diphosphoribose) polymerization. Without inhibitors of poly(adenosine diphosphoribose) polymerase such as nicotinamide or 3-aminobenzamide, DNA repair synthesis following UV irradiation was found to occur normally in the cells of patients. These data suggest that DNA repair is disturbed under special conditions in the lymphocytes of SLE patients.

Benzamides↗
PubMed1985

[The use of 99mTc-dimercaptosuccinic acid renoscintigraphy in the evaluation of differential renal function].

We studied the total and differential renal function by 99mTc-dimercaptosuccinic acid (DMSA) renoscintigraphy and present a formula to estimate the renal depth for the Japanese and the attenuation coefficient which influenced renal uptake. Total renal uptake of 99mTc-DMSA correlated well with creatinine clearance and with the PSP test, and there was a close correlation between its relative uptake and relative function as determined by 99mTc-diethylenetriaminepentaacetic acid (DTPA) renography. Therefore differential renal function test with 99mTc-DMSA renoscintigraphy was found to have clinical utility. We also demonstrated 99mTc-DMSA renoscintigraphy provided useful morphological information.

Adolescent↗
PubMed1984

Kynurenine metabolism in vitamin-B-6-deficient rat liver after tryptophan injection.

Tryptophan contents of liver, serum and kidney were determined in normal and vitamin-B-6-deficient rats after tryptophan injection. Tryptophan contents of normal and B-6-deficient liver were different, but not those in serum and kidney. Both kynurenine and 3-hydroxykynurenine accumulated in B-6-deficient liver more than in the normal. The 3-hydroxykynurenine contents after tryptophan injection (30 mg/100 g body wt.) increased to 1380 nmol/g of liver at 1-1.5 h, a value sufficient to produce xanthurenate, in view of the Km value of kynurenine aminotransferase. The enzymes metabolizing kynurenine were assayed at various times after tryptophan injection. The activity of kynureninase holoenzyme in B-6-deficient liver was much decreased, but the activity of total enzyme was not changed. It appeared that a high dose of tryptophan in B-6-deficient rats could cause a greater deficiency of pyridoxal 5-phosphate. Tryptophan metabolism in B-6-deficient rat liver after tryptophan administration is discussed.

Animals↗
PubMed1984

High tyrosine protein kinase activities in soluble and particulate fractions in bone marrow cells.

High tyrosine protein kinase activities were detected in soluble and particulate forms from bone marrow cells using synthetic peptide (Glu-Asp-Ala-Glu-Tyr-Ala-Ala-Arg-Arg-Arg-Gly) as a substrate. Total activity of tyrosine protein kinase was 2.4 times higher in the soluble fraction but the specific activity was slightly higher in the particulate one. Mg2+ or Mn2+ requirements of these two enzymes for maximal activity were quite different from each other. Physiological significance of these two forms of enzymes is briefly discussed.

Animals↗
PubMed1984

Enhancement of the rate of spontaneous mutation to 6-thioguanine resistance in mammalian cells by polyamine depletion.

Several lines of evidence have suggested, but not proved, that polyamines are associated with DNA in intact cells. In an attempt to investigate the roles of polyamines in gene-associated functions, we examined the effects of polyamine depletion on the spontaneous mutation rate in a rat basophilic leukemia cell line. The frequency of 6-thioguanine-resistant mutant cells increased by approximately 9-fold as a result of the treatment with alpha-difluoromethylornithine, a potent inhibitor of ornithine decarboxylase (EC 4.1.1.17). This increase was prevented by supplementing the cultures with putrescine, suggesting that polyamine depletion, but not the direct mutagenic action of the enzyme inhibitor, is responsible for the mutant-increasing effect. These results suggest that polyamines may participate in the conservation of genetic information at either the chromosome or gene level.

Animals↗
PubMed1983

Decrease in the average size of replicons in a Werner syndrome cell line by Simian virus 40 infection.

We have measured the distance between replicon initiation sites as well as the rate of DNA chain elongation in Simian Virus 40 (SV40)-infected and uninfected Werner syndrome (WS) and normal cell lines by DNA fiber-autoradiography. There was no difference in the rate of chain elongation among these cell lines. On the other hand, the replicon center-to-center distance was clearly longer in WS fibroblasts than that in normal fibroblasts. SV40 infection changed the center-to-center distance in WS cells toward that in normal cells.

Autoradiography↗
PubMed1983

Purification, characterization and identification of rat liver mitochondrial kynurenine aminotransferase with alpha-aminoadipate aminotransferase.

Kynurenine aminotransferase (L-kynurenine:2-oxoglutarate aminotransferase (cyclizing), EC 2.6.1.7) was purified 378-fold from rat liver mitochondria by digitonin solubilization, heat treatment, DEAE-Sepharose CL-6B chromatography, Sephadex G-100 gel filtration, hydroxyapatite chromatography and chromatofocusing. Elution patterns of alpha-aminoadipate aminotransferase (EC 2.6.1.39) activity were identical with those of kynurenine aminotransferase activity on all column chromatographies. The ratios of the two specific activities were constant throughout the purification. On polyacrylamide gel electrophoresis both activities were detected at the same position. Both enzymatic activities showed the same inactivation curves upon heat inactivation at various temperatures. alpha-Aminoadipate showed competitive inhibiton against kynurenine or 3-hydroxykynurenine. alpha-Ketoadipate was utilized in the kynurenine aminotransferase reaction as an amino acceptor in place of alpha-ketoglutarate. The Km value for alpha-ketoadipate was 10 microM, lower than for alpha-ketoglutarate. These observations indicate that kynurenine aminotransferase is identical with alpha-aminoadipate aminotransferase. The Km values of purified kynurenine aminotransferase were determined at pH 6.5 as: kynurenine, 4.3 mM; pyridoxal 5'-phosphate, 4.2 microM; alpha-ketoglutarate, 20 microM (kynurenine substrate), and 3-hydroxykynurenine, 5.7 mM; pyridoxal 5'-phosphate, 1.7 microM; alpha-ketoglutarate, 13 microM (3-hydroxy-kynurenine substrate). The enzyme was strongly inhibited by Hg2+ and p-chloromercuribenzoate.

2-Aminoadipate Transaminase↗
PubMed1981

The mode of genetic transmission of gouty family with increased phosphoribosylpyrophosphate synthetase activity.

The mode of genetic transmission of gout and increased activity of phosphoribosylphrophosphate synthetase (PRPPS) was studied in one family. Among 15 members of Family F, two male members had gout and had PRPPS activity of erythrocyte lysates three times higher than normal subjects. Five female members had activity 2.5 times higher than normal. The difference between the activities of male and female affected members was statistically significant (P less than 0.05). To examine the genetic trait of this abnormal PRPPS, the incorporation of 3H-adenine into erythrocytes or lymphocytes was studied using autoradiography. The number of grains which show the uptake of labeled adenine into cells revealed a normal distribution pattern in two normal persons and in two male patients, and a mixed pattern of the two cell populations in two female affected members. These results suggested mosaicism in female members and X-linked dominant transmission of this trait. Thermal inactivation of PRPPS of an affected female was intermediate between that from a normal subject and that from the affected males. This result showed the heterogeneity of the PRPPS from the hemolysate of an affected female. The genotype of PRPPS on the X-chromosome was assumed and the lod score between PRPPS and Xg was also estimated. From these findings and electrophoretical study, it was suggested that the abnormal enzyme was a mutant enzyme transmitted in an X-linked dominant trait, and that the mutation occurred on the structural gene of the PRPPS.

Adenine↗
PubMed1981

Effect of tryptophan metabolites and metal ions on the purified kynureninase from rat liver.

Kynureninase purified from rat liver was inhibited by 3-hydroxyanthranilate, or anthranilate, and slightly by 5-hydroxyanthranilate. However, tryptophan metabolites other than anthranilate and its derivatives, and also alpha-keto acids and alanine did not affect the activity of this enzyme. Kynureninase was also inhibited and inactivated by metal ions, especially Hg2+ and Zn2+. On the other hand Mg2+, Ca2+ and monovalent cations had no effect on the activity of the enzyme. The reductants, such as dithiothreitol, reduced glutathione and mercaptoethanol, prevented this inactivation. p-Chloromercurybenzoate (CMB) and N-ethylmaleimide inhibited the enzyme action. Kynureninase which had been completely inactivated by Hg2+ or CMB could be reactivated with excess dithiothreitol, indicating that enzyme inactivation can be attributed to the blocking of sulfhydryl groups. Five sulfhydryl groups per subunit of the enzyme molecule were detected using CMB and mercury orange.

Animals↗
PubMed1980

Purification and properties of kynureninase from rat liver.

Kynureninase [L-kynurenine hydrolase EC 3.7.1.3] has been purified 614-fold from rat liver cytosol. The purification procedure involved pH treatment, ammonium sulfate fractionation, Sephadex G-100 gel filtration, DEAE-Sepharose CL-6B chromatography, extraction with 40% saturated solution of ammonium sulfate and hydroxyapatite chromatography. The enzyme was found to be homogeneous by the criteria of disc gel electrophoresis. SDS-gel electrophoresis and sucrose gradient centrifugation. The enzyme was obtained as a holo-enzyme which showed an absorption maximum at 420 nm. In the absence of pyridoxal 5-phosphate (PLP) the enzyme was dissociated into an apoenzyme. The isoelectric points of holoenzyme and apoenzyme are 5.7 and 6.1. Sucrose gradient centrifugation and SDS-gel electrophoresis gave molecular weight estimates of 95,000 and 55,000, respectively. The optimum pH shifted to higher pH with increase in the concentration of PLP. The Michaelis constants were determined as follows: kynurenine, 240 microM; 3-hydroxykynurenine, 13 microM; PLP, 0.1-1.7 microM. The maximum velocity for 3-hydroxykynurenine was 11 times higher than that for kynurenine at pH 7.7. This enzyme can be regarded as a 3-hydroxykynureninase type enzyme.

Animals↗
PubMed1980

HLA-DRw3 in juvenile onset diabetes mellitus in Chinese.

Thirty-nine juvenile onset diabetes mellitus (JOD) patients and 57 healthy Chinese were HLA-typed in Taiwan. The incidence of HLA-DRw3 was significantly increased in patients when compared with the control group (R.R. = 5.8, P = 0.0027). The frequencies of HLA-B17, which showed linkage disequilibrium with DRw3, and Bw54 were increased in patients, but these increases were not significant because of the small number tested. The DR antigen associated with JOD was the same among Chinese and Caucasians, which suggested that at least one of the susceptibility genes to JOD would be commonly in linkage disequilibrium with DRw3 in the two populations.

Adult↗