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Biomedical subjects

F Takeuchi

Publications and source records attributed to F Takeuchi.

At least 91 records · Page 5Linked to original sources
PubMed1990

Inhibition of avian myeloblastosis virus reverse transcriptase by aurochloric acid.

We investigated the inhibitory effects of aurochloric acid (AuCl4H) on reverse transcriptase (RT) derived from avian myeloblastosis virus and DNA polymerase alpha (pol. alpha) purified from HeLa S3 cells. The activities of RT, pol. alpha and E. coli DNA polymerase I (pol. I) with dTTP as the substrate were inhibited 50% at AuCl4H concentrations of 18 microM, 43 microM and 230 microM, respectively. AuCl4H inhibited RT activity competitively with respect to the substrate, dTTP, and uncompetitively with the template/primer, (rA)n(dT)12-18. In assays with dGTP as the substrate, 50% inhibitions of RT, pol. alpha and pol. I activities were observed at AuCl4H concentrations of 100 microM, 450 microM and 580 microM, respectively. AuCl4H inhibited RT activity uncompetitively with respect to the substrate, dGTP, and noncompetitively with the template/primer, (rC)n(dG)12-18. AuCl4H at concentrations causing more than 50% inhibition of RT activity had little inhibitory effect on the colony-forming ability of HeLa cells or their syntheses of DNA, RNA and protein.

Avian Myeloblastosis Virus↗
PubMed1990

Restriction fragment length polymorphism of complement C4 in Japanese patients with rheumatoid arthritis and normal Japanese.

Restriction fragment length polymorphism (RFLP) of the two genes for complement C4A and C4B was studied in 56 Japanese patients with rheumatoid arthritis (RA) and 161 normal individuals. HindIII digestion revealed six common patterns, from which the segregation of three common RFLP-types were deduced; 32-15 kb, 32-25 kb, and 32-20-13-6.5 kb. The last type showed positive associations with C4B5 and HLA-DR4. In the RA patients, an increase of this type was found as well as a decrease of the 32-15 kb/32-25-15 kb heterozygotes.

Arthritis, Rheumatoid↗
PubMed1990

Lack of gene deletion for complement C4A deficiency in Japanese patients with systemic lupus erythematosus.

The frequency of C4A gene deletion was studied in Japanese patients with systemic lupus erythematosus (SLE) and was compared with healthy controls. DNA preparations were extracted from peripheral blood leukocytes from 59 patients with SLE and from 166 healthy persons, and digested by restriction enzymes. They were hybridized with C4 complementary DNA by the Southern blotting method and the deletion of C4A gene was judged from restriction fragment length polymorphism. At the same time phenotypic C4A deficiency (C4AQ0) was measured. Our results showed that the frequency of phenotypic C4A deficiency was 44.1% in Japanese patients with SLE and this value was comparable with that (43.2%) in Caucasian patients. On the other hand the deletion of C4A gene was not found in Japanese patients with SLE (0%), or in healthy controls (0.6%). Our results indicate that C4AQ0 may contribute to the pathogenesis of SLE beyond the ethnical differences but Japanese patients with SLE have a different genetic background from Caucasian patients with the C4A gene deleted.

Alleles↗
PubMed1990

Protease-activated form of protein kinase C with Mr 80,000 generated from rat liver plasma membrane by trypsin-like protease.

New type of protease-activated form of protein kinase C was generated from rat liver plasma membrane by action of endogenous trypsin-like protease. The molecular mass was estimated to be about 80,000 by immunoblot analysis which was slightly smaller (approximately 2,000) than that of native protein kinase C. The protein kinase activity was 2-times stimulated by Ca2+ and phospholipid and inhibited by the synthetic peptide derived from the pseudosubstrate region of protein kinase C. This type of activated kinase was produced in purified enzyme system in the absence of either Ca2+ or phospholipid or both. These results suggest that limited proteolysis generating the active form of Mr 80,000 may occur on the inactive form of protein kinase C.

Amino Acid Sequence↗
PubMed1990

[Long-term follow-up of tetralogy of Fallot corrected by Okamura's method under simple deep hypothermia].

Corrective surgeries for TOF (Tetralogy of Fallot) were performed in 350 patients from 1967 to 1983 by Okamura's method under simple deep hypothermia. Radical operations were done in all patients, including very young children. The operative techniques had several differences from the standard procedure. Patients were operated on without any extracorporeal perfusion, the VSD was closed by a patch which was attached firmly to the margin of VSD using cross mattress sutures and the right ventricular outflow tract was dilated by infundibular myectomy only, with no use of outflow-patch-plasty. One hundred ten out of 350 patients were investigated by questionnaire and their responses showed that they had few long-term problems. ECG, X-ray, echocardiography and stress test by treadmill were performed in 26 cases. They were divided into two groups by the presence or absence of pulmonary regurgitation (PR). The CTR of the PR (+) group was larger than the PR (-) group (p less than 0.05). There was no statistical difference in cardiac function between the two groups. Few arrhythmias were observed during the exercise test. No residual shunts were found in any of the cases. The occurrence of PR was relatively rare in those who were operated on before their second birthdays. These results suggest that our surgical techniques under simple deep hypothermia are adequate to correct TOF.

Adult↗
PubMed1989

Putative amino acid sequence of HLA-DRB chain contributing to rheumatoid arthritis susceptibility.

The association between HLA-DR4 and rheumatoid arthritis (RA) has been established in many ethnic groups. To clarify the determinant of susceptibility to RA, a polymorphic segment of the HLA-DRB gene was amplified in vitro by polymerase chain reaction and analyzed with oligonucleotide probes specific for the HLA-DR4 DNA sequences. A particular sequence encoding amino acids Gln70-Arg71-Arg72-Ala73-Ala74 showed a strong association with RA (p less than 0.005, relative risk 6.0). This amino acid sequence occurs in the DRB molecules with three RA-associated specificities, DR4/Dw14, DR4/Dw15, and DR1. DR4/Dw4, which is common in Caucasian RA patients, has a strikingly similar amino acid sequence Gln70-Lys71-Arg72-Ala73-Ala74 in terms of polarity and charge profiles. Other RA nonassociated sequences differ from this sequence by at least one amino acid substitution that causes the change of the net charge. The composition of amino acid residues at the positions 70-74 may play a crucial role in the pathogenesis of RA.

Amino Acid Sequence↗
PubMed1989

Association of complement alleles C4AQ0 and C4B5 with rheumatoid arthritis in Japanese patients.

We investigated polymorphisms of complement components C2, C4, and factor B (BF) in Japanese patients with rheumatoid arthritis (RA). The frequencies of C4AQ0 (32.1%) and C4B5 (35.9%) among RA patients were significantly higher than among healthy control subjects. C4B5 was strongly associated with HLA-Bw54, Bw59, DR4.1, and DQw4. C4AQ0 showed no association with HLA-Bw54 or Bw59, but there was weak association with HLA-DR4.1 and DQw4. The number of persons with both C4AQ0 and C4B5 was significantly higher in the RA patient group (relative risk 13.5). C2C and BFS were the most common alleles in RA patients, as well as in healthy control subjects. These data support the existence of 2 different putative susceptibility haplotypes (HLA-Bw54 or Bw59;C2C; BFS;C4A3;C4B5;DR4.1;DQw4 and C2C;BFS; C4AQ0;C4B1 or C4B2) in Japanese patients with RA.

Alleles↗
PubMed1989

Erythrocyte adenine PRPP availability in two types of APRT deficiency using silicon oil method.

Erythrocyte phosphoribosylpyrophosphate availability for adenine was measured by silicon oil method previously described. The homozygotes of Japanese type APRT deficiency (n = 6, from 4 families) showed 4.3 +/- 2.7% (mean +/- standard deviation) of adenine PRPP availability and the heterozygotes (n = 5) showed 86.0 +/- 6.0% of adenine PRPP availability. All homozygotes of Japanese type APRT deficiency from 4 unrelated families show the equally decreased adenine PRPP availability and it supports the presumption of the presence of the similar defect of APRT in all families. In a Japanese family of complete APRT deficiency, adenine PRPP availability of the homozygote was undetectable and that of the heterozygote was normal low (54.3% of normal mean activity). The adenine PRPP availability of the heterozygote of complete APRT deficiency was diagnostically different from that of the homozygotes of Japanese type APRT deficiency, despite, these two conditions showed almost the same erythrocyte APRT activity. These results prove that the silicon oil method previously written is the rapid and useful method for differential diagnosis between two types of APRT deficiency.

Adenine↗
PubMed1989

Locating accuracy of a current source of neuromagnetic responses: simulation study for a single current dipole in a spherical conductor.

The locating accuracy of a current dipole of neuromagnetic responses in a spherical conductor was examined in terms of the residual field which was a difference between the measured and calculated magnetic fields in a least squares fitting. Characteristics of the residual field as a function of the noise field, dipole depth, and number of measurement points were studied by computer simulations. The confidence region of the dipole location was determined by changing a dipole parameter along a coordinate axis until the sum of squares of the residual field increased by a factor given for each axis. As an example for a dipole at 2.4 cm depth, 95% confidence limits extend 2 mm along the transverse axis, 6 mm along the longitudinal axis, and 5 mm along the radial axis when the signal-to-noise ratio is 2.5 and the measurement points are 42. The method was applied to auditory evoked magnetic responses to examine location differences of the dipoles for different stimuli in the auditory cortex.

Auditory Cortex↗
PubMed1989

Susceptibility epitope on HLA-DR beta chain for rheumatoid arthritis and the effect of the positivity on the clinical features.

A highly significant association of an amino acid sequence, '70Q71R72R73A74A' located on the DR beta-1 chain, with rheumatoid arthritis (RA) was confirmed in Japanese patients using polymerase chain reaction. The '70QRRA74A' is the most plausible candidate of susceptibility epitope in Japanese RA patients. The patients carrying the sequence showed slightly higher but not significant familial incidence. The positivity of the 'QRRAA' showed no effect on the positivity of the rheumatoid factor, rheumatoid nodules, and extra-articular signs. Also no significant differences in other clinical parameters (ESR, CRP, Hb, A/G) and age at onset were observed regarding the positivity. The risk that the 'QRRAA' positive subjects would suffer from RA was estimated to be about 1.3% which meant 7.2 times easier to get RA than those without 'QRRAA'.

Adult↗
PubMed1989

Kynurenine metabolism and xanthurenic acid formation in vitamin B6-deficient rat after tryptophan injection.

Normal and vitamin B6-deficient rats received an intraperitoneal injection of 30 mg/100g of body wt, and the contents of metabolites in kidney or plasma and the related enzyme activities in kidney were determined. The contents of kynurenine and 3-hydroxykynurenine in B6-deficient rat plasma and kidney were much higher than those in normal rat. The changes of those contents in plasma were parallel to those in kidney, but not in liver. The contents of kynurenic acid and xanthurenic acid in B6-deficient liver, plasma, and kidney were also much higher than those in normal rats. However, the changes of those contents in plasma were parallel to those in liver, but not in kidney. Xanthurenic acid and kynurenic acid accumulated to a much greater extent in kidney than in plasma and liver. Kidney kynureninase activity was very low, but kynurenine aminotransferase activities were very high. These observations indicated that the production of xanthurenic acid after tryptophan injection was favorable in B6-deficient kidney with respect to enzyme activities and substrate concentrations, and suggested that kidney took up kynurenine or 3-hydroxykynurenine from blood and after conversion of them it excreted xanthurenic or kynurenic acid into urine.

Animals↗
PubMed1989

Effects of galactose depletion from oligosaccharide chains on immunological activities of human IgG.

We previously reported a decrease in the content of galactose residues in oligosaccharide chains of serum IgG from patients with rheumatoid arthritis, which was presumed to affect the 3 dimensional structure of CH2 domain. In the present study, we prepared the galactose depleted IgG (agalacto IgG) and characterized its immunological activities. Significant reduction in Clq binding and Fc receptor binding was observed in agalacto IgG. However, IgM rheumatoid factor binding and protein A binding were the same as with intact IgG. Our results implied the biological function of the carbohydrate moiety of human IgG.

Arthritis, Rheumatoid↗
PubMed1989

[A case of pulmonary sarcoidosis with calcification in the lung].

A 35 year-old male farmer presented with complaints of productive cough and sputum. The chest X-ray films showed reticulonodular shadows bilaterally in the upper and middle lung fields, segmental infiltration in the right lung, and no BHL. Tuberculin reaction was negative. Serum angiotensin converting enzyme level was 26.5 IU/ml. Precipitating antibodies for Thermophilic actinomycetes and M.f. were negative. BAL showed moderate lymphocytosis (24.3%), and CD 4/8 was 1.67. A biopsy specimen of right scalene lymph node showed epithelioid cell granulomas and TBLB epithelioid cell granulomas and spot-like calcification. Pulmonary sarcoidosis with calcification in the lung is very rare.

Adult↗
PubMed1988

Calcium uptake into renal brush border membranes in vitamin B6 deficient rats.

The calcium uptake into renal brush border membrane vesicles, which has been purified from normal or vitamin B6 deficient rat renal cortex by calcium precipitation, was investigated. The values of Km and Vmax were determined to be 1.89 mM and 4.26 nmol of Ca2+/mg of protein per 20s in vitamin B6 deficient rats, respectively. This Vmax was lower than that of normal rats. The chemical compositions of renal brush border membranes did not display a difference in normal and vitamin B6 deficient rats. The amount of brush border membranes isolated from 1 gram of renal cortex in vitamin B6 deficient rats was less than in normal rats.

Animals↗