Biomedical subjects

K Matsuta

Publications and source records attributed to K Matsuta.

At least 37 records · Page 2Linked 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↗

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

Purification and characterization of extracellular phospholipase A2 from human synovial fluid in rheumatoid arthritis.

Extracellular phospholipase A2 was purified about 1.7 X 10(5) fold to near homogeneity from human synovial fluid of rheumatoid arthritis by sequential use of column chromatographies on heparin-Sepharose, butyl-Toyopearl, and reversed-phase HPLC. The final preparation showed a single band on SDS-polyacrylamide gel electrophoresis, and its molecular mass was estimated to be approximately 13,700 daltons. The purified enzyme had a pH optimum of 9.0 and required Ca2+ for maximum activity. It hydrolyzed phosphatidyl-ethanolamine more effectively than phosphatidylserine and phosphatidylcholine. These properties were similar to those of an extracellular phospholipase A2 detected in the peritoneal cavity of caseinate-treated rats.

Arthritis, Rheumatoid↗

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

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↗

PubMed1988

Amino acid composition and NH2-terminal amino acid sequence of human phospholipase A2 purified from rheumatoid synovial fluid.

The amino acid composition and partial NH2-terminal amino acid sequence of an extracellular phospholipase A2 in human rheumatoid synovial fluid were determined. The predominant amino acids in the phospholipase A2 were cysteine, glycine, arginine, and lysine, suggesting that it is a basic one. The NH2-terminal 34 amino acids were found to be as follows: Asn-Leu-Val-Asn-Phe-His-Arg-Met-Ile-Lys-Leu-Thr-Thr-Gly-Lys-Glu-Ala-Ala-Leu- Ser-Tyr-Gly-Phe-Tyr-Gly-Cys-X-Cys-Gly-Val-Gly-Gly-Arg-Gly The enzyme contains Phe-5, Met-8, Ile-9, Tyr-24, Gly-25, Cys-26, Cys-28, Gly-29, Gly-31, Gly-32, and Gly-34 residues, all of which are conserved in most of the sequenced phospholipase A2. The remarkable feature of this enzyme was the absence of Cys-11, which is conserved in the "Group I" enzyme family. This is the first report concerning partial amino acid sequences of human non-pancreatic phospholipase A2.

Amino Acid Sequence↗

PubMed1987

Differential inhibitory effects of auranofin on leukotriene B4 and leukotriene C4 formation by human polymorphonuclear leukocytes.

Auranofin (AF) is a newly introduced oral gold compound having antirheumatic properties, and its efficacy in the treatment of bronchial asthma is now under investigation. In this study, we examined the effects of AF on leukotriene (LT) formation by human polymorphonuclear leukocytes (PMNs) stimulated with the calcium ionophore A23187. AF inhibited LTC4 formation in a dose-dependent manner with an IC50 (concentration required to produce 50% inhibition of control) of 3.2 microM. In contrast, LTB4 formation was not prevented by AF at concentrations up to 6 microM, but it was reduced to 59 +/- 4% (mean +/- SE, N = 3) of control by an 8 microM concentration. As a next step, we explored the mechanisms of the differential inhibitory effects of AF using cell-free systems. When arachidonic acid (AA) and reduced glutathione (GSH) were used as substrates, AF inhibited LTC4 synthesis more effectively (IC50 = 14 microM) than LTB4 synthesis (IC50 = 100 microM). However, LTB4 and LTC4 syntheses from LTA4 were affected only slightly by AF within the concentrations tested (3-100 microM). These results in the cell-free systems indicate that the inhibition of LT formation was caused by a reduction of LTA4 synthesis and that the differential inhibitory effects can be ascribed to the higher Km value of glutathione S-transferase for LTA4 than that of LTA4 hydrolase in PMNs. In accordance with this hypothesis, LTC4 synthesis was more dependent than LTB4 synthesis on LTA4 concentrations within 25-100 microM, and AA-861, a 5-lipoxygenase inhibitor, caused similar differential inhibitory effects on the formation of LTs by intact PMNs. The inhibitory effect of AF on LT formation at physiological concentrations may play some role in the efficacy of this drug.

Animals↗

PubMed1987

Kallikrein in synovial fluid with rheumatoid arthritis.

The levels of kallikrein and collagenase in synovial fluid from rheumatoid arthritis (RA) patients were examined and the role of kallikrein in procollagenase activation is discussed. Both prekallikrein and active kallikrein in synovial fluid from patients with RA were significantly elevated when compared to synovial fluid from patients with osteoarthritis (OA). In RA synovial fluid, the ratio of the active form to total kallikrein was also higher than that in OA synovial fluid. Both active collagenase and the alpha 2-macroglobulin (alpha 2M)-collagenase complex in RA synovial fluid were higher than in OA synovial fluid. A partial correlation (r = 0.58) between active kallikrein and total collagenase (active and alpha 2M-collagenase complex) was observed in RA synovial fluid. These observations indicate that both kallikrein and collagenase are associated with the destruction of cartilage, but the role of kallikrein in procollagenase activation was not fully clarified.

Adult↗

PubMed1986

Hyaluronic acid is an endogenous inducer of interleukin-1 production by human monocytes and rabbit macrophages.

When human peripheral monocytes and rabbit peritoneal macrophages were incubated with hyaluronic acid, the media were found to contain interleukin-1 (IL-1) activity and to stimulate collagenase production by rabbit fibroblasts. A digestion of hyaluronic acid by testicular hyaluronidase decreased the IL-1 inducing activity. Polymixin B, an inhibitor of endotoxin, did not exert any effect towards the action of hyaluronic acid. Hyaluronic acid also stimulated human polymorphonuclear leucocytes to produce IL-1 like activity. These results indicate that hyaluronic acid is an endogenous IL-1 inducer and may play important roles in the pathological and/or physiological changes of connective tissues.

Animals↗

PubMed1985

Rapid method for the diagnosis of partial adenine phosphoribosyltransferase deficiencies causing 2,8-dihydroxyadenine urolithiasis.

More than half of the Japanese patients with 2,8-dihydroxyadenine urolithiasis only partially lack adenine phosphoribosyltransferase (APRT), while all the Caucasian patients with the same disease completely lack the enzyme. APRT activities in healthy heterozygotes for the complete APRT deficiencies were at the same levels as the Japanese patients, and simple enzyme assay does not distinguish between these two conditions. We have previously shown, using viable T-cells, that the enzyme was non-functional in the cells from the Japanese patients although they contain considerable APRT activities in the cell extracts. In the present investigations, we devised a rapid method using erythrocytes for the diagnosis of partial APRT deficiencies accompanied by severe impairment in adenine metabolism causing 2,8-dihydroxyadenine lithiasis. Thus, erythrocytes from three different families with 2,8-dihydroxyadenine urolithiasis associated with partial APRT deficiencies incorporated only minimal amounts of radioactive adenine, while normal erythrocytes incorporated significant amounts. These data indicate that severe impairment in adenine metabolism is shown not only in viable T-cells but also in viable erythrocytes. The present procedures provide a rapid method suitable for routine clinical use for the diagnosis of partial APRT deficiencies causing 2,8-dihydroxyadenine lithiasis.

Adenine↗

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↗

PubMed1984

Role of protease--protease-inhibitor complexes in inflammation.

Neutrophils accumulate and release proteolytic enzymes at the site of acute inflammation. These proteases cause tissue damage but are inactivated by protease-inhibitors which have been thought to finish their activity. We paid attention to these protease--protease-inhibitor complexes and examined their roles. Trypsin was used as a proteolytic enzyme and was mixed with an excess of purified alpha 1-antitrypsin (alpha 1AT). The trypsin-alpha 1AT complex was separated from native alpha 1AT by column chromatography. Then the complex was incubated with human neutrophils and lysosomal enzyme release was examined. Significant enzyme release was observed when neutrophils were incubated with the complex, but the amount of enzyme release from the cells was not obvious when neutrophils were incubated with alpha 1AT or trypsin alone. The amount of lysosomal enzyme release was proportional to the amount of the complex added. Further study revealed that the complex did not have much influence on neutrophil chemotaxis or superoxide radical generation, but could activate complement by the classical pathway. These facts indicate that protease--protease-inhibitor complexes play a role in prolonging inflammation.

Adult↗

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

'Gelatinase-like' activity from articular chondrocytes in monolayer culture.

In addition to releasing collagenase and proteoglycanase activity, rabbit articular chondrocytes in monolayer culture released into the culture medium, latent, neutral enzyme activity which when activated by p-aminophenylmercuric acetate degraded fluorescein-labeled polymeric rat tail tendon Type I collagen and the tropocollagen TCA and TCB fragments of human Type II collagen into smaller peptides at 37 degrees C. Enzyme activity was abolished if p-aminophenylmercuric acetate-activated culture medium was preincubated with 1.10-phenanthroline, a metal chelator. Thus, articular chondrocytes in monolayer culture are capable of producing neutral proteinases which acting together can result in complete degradation of tendon and cartilage collagen to small peptides.

Animals↗

PubMed1981

Neutral proteinases from articular chondrocytes in culture. 2. Metal-dependent latent neutral proteoglycanase, and inhibitory activity.

Monolayer and spinner cultured rabbit articular chondrocytes released into the medium latent metal-dependent enzyme with activity against bovine proteoglycan. Pretreatment of medium with p-aminophenylmercuric acetate or trypsin followed by soybean trypsin inhibitor significantly increased enzyme activity. The monolayer-cultured chondrocytes released more of this activity than spinner cultures. The neutral proteoglycanase activity increased with medium concentration and incubation time. Like the human cartilage proteoglycanase, its pH optimum on proteoglycan subunit was 7.25. Gel filtration on BioGel P-30 indicated that the proteoglycanase occurred in two molecular weight forms: 20 000--30 000 and 13 000. The latent enzyme was about 30 000--40 000. The metal-chelators, o-phenanthroline (5 mM) and EDTA (10 mM) inhibited the activated proteoglycanase almost completely, but trypsin and chymotrypsin inhibitors had little effect. The cultured chondrocytes also released into the media a heat-labile inhibitor against the proteoglycanase. The inhibitory activity was present in the nonactivated media and eluted on Sephadex G-100 chiefly at a position corresponding to molecular weights of 10 000--13 000.

Animals↗