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Biomedical subjects

N Tsuchiya

Publications and source records attributed to N Tsuchiya.

At least 73 records · Page 4Linked to original sources
PubMed1999

Overlapping peptide-binding specificities of HLA-B27 and B39: evidence for a role of peptide supermotif in the pathogenesis of spondylarthropathies.

OBJECTIVE: Previous studies indicated the increase of HLA-B39 among HLA-B27 negative patients with spondylarthropathies (SpA). This study was performed to examine whether the natural ligands of HLA-B27 are capable of binding to HLA-B39. METHODS: Peptides were synthesized according to the sequences of known natural ligands of HLA-B27 or B39 and were tested for their binding to HLA-B*3901 and B*2705 by quantitative peptide binding assay, using a TAP-deficient RMA-S cell line transfected with human beta2-microglobulin and HLA class I heavy chain genes. RESULTS: Four of the 10 HLA-B27 binding peptides significantly bound to HLA-B*3901. All 4 peptides had hydrophobic/aromatic amino acids (Leu or Phe) at the C-terminus. In contrast, peptides with basic residues (Lys, Arg) or Tyr at the C-terminus did not bind to B*3901. In parallel experiments, 1 of the 2 natural ligands of HLA-B*3901 was found to bind to B*2705. CONCLUSION: A subset of natural HLA-B27 ligands was capable of binding to B*3901. In addition to Arg at position 2 (Arg2), hydrophobic/aromatic C-terminal residues, such as Leu or Phe, seemed to be crucial for the cross-specificity. These results suggested that HLA-B27 and B39 recognize overlapping peptide repertoires, supporting the hypothesis that the peptides presented by both of these class I antigens play a role in the pathogenesis of SpA.

Amino Acid Sequence↗
PubMed1999

Identification of the gene variations in human CD22.

CD22, a member of the immunoglobulin superfamily, is a B-cell transmembrane glycoprotein that acts as an accessory-signaling component of the B-cell antigen receptor (BCR). Recent evidence indicating the role of CD22 as a negative regulator of BCR signal transduction prompted us to test the possibility that genetic variations of human CD22 may be associated with autoimmune diseases. In this study, variation screening of the entire CD22 coding region was performed, and possible association with rheumatic diseases was tested, using the genomic DNA from 207 healthy Japanese individuals, 68 patients with systemic lupus erythematosus (SLE), and 119 patients with rheumatoid arthritis (RA). Through the variation screening, seven non-synonymous and four synonymous substitutions were identified. In addition, single base substitutions were found in two introns flanking exon-intron junctions. Among these variations, Q152E substitution within the second extracellular domain was observed with a marginally higher frequency in the patients with SLE (3/68, 4.4%) than that in healthy individuals (1/207, 0.5%) (P=0.048. SLE vs healthy individuals), although this difference was no longer significant after correction for the number of comparisons (Pc=0.62). No significant association was observed between any of the variations and RA. These findings indicate that a number of genetic variants are present in CD22, and suggest that CD22 could be considered a candidate for the susceptibility genes to autoimmune diseases.

Adolescent↗
PubMed1999

MIC-A polymorphism in Japanese and a MIC-A-MIC-B null haplotype.

A polymorphic gene, MIC-A, is one of the MIC family of genes which is composed of a group of homologous genes interspersed in the class III and class I regions of the major histocompatibility complex. MIC-A is located 46 kilobases (kb) centromeric of HLA-B, and is preferentially expressed in the epithelial cells and intestinal mucosa. Recently, MIC-A and the closely related MIC-B were reported as the molecules that conferred specificity in the recognition by the Vdelta1gammadeltaT cells. In the present study, polymorphic exons 2, 3, and 4 of the MIC-A gene were analyzed using the polymerase chain reaction-single-strand conformation polymorphism method. The number of patterns found in exons 2, 3, and 4 were 5, 6, and 4, respectively, in 114 healthy Japanese subjects. Eight MIC-A alleles were observed in Japanese individuals, among which one, tentatively named MIC-AMW, has not previously been reported. There was a strong linkage disequilibrium between MIC-A and HLA-B loci: each MIC-A allele showed strong association with a particular HLA-B group. In contrast, B*3901 showed association with multiple MIC-A alleles. Furthermore, the existence of a MIC-A-MIC-B null haplotype, which is associated with HLA-B*4801, was identified. In this haplotype, a large-scale deletion (of approximately 100 kb) including the entire MIC-A gene was indicated and the MIC-B gene possessed a stop codon.

Alleles↗
PubMed1999

Significant association of HLA-B and HLA-DRB1 alleles with cleft lip with or without cleft palate.

Nucleotide sequence level typing of HLA-B, -DRB1, and -DPB1 alleles was performed on Japanese patients with cleft lip with or without cleft palate (CL/P). Two HLA-B alleles, B*1501 and B*5101, showed a significant positive association with CL/P. The increase of B*1501 was evident in female patients (OR=3.6, Pc=0.003), whereas the increase of B*5101 was evident in male patients (OR=3.7, Pc < 0.001). One HLA-DRB1 allele, HLA-DRB1*0802 also showed an increase in CL/P patients. Conversely, HLA-B*4403 and DRB1*1302 were not observed in the patient group (Pc=0.01 and Pc=0.02, respectively). No HLA-DPB1 alleles showed significant association with CL/P. Thus, the present study indicates that HLA alleles, or closely linked loci, may be involved in the pathogenesis of CL/P.

Alleles↗
PubMed1999

Association of tumor necrosis factor receptor 2 (TNFR2) polymorphism with susceptibility to systemic lupus erythematosus.

Multiple genetic as well as environmental factors are considered to be involved in the development of systemic lupus erythematosus (SLE). A number of previous studies have suggested a possible role for tumor necrosis factor (TNF) in the pathogenesis of SLE. In addition, one of the candidate loci suggested by the genome-wide linkage analysis corresponds to the chromosomal position encompassing the TNF receptor 2 gene (TNFR2). The purpose of this study was to analyze the polymorphism of TNFR2 and its possible association with the susceptibility to SLE, using the case-control association analysis. Polymorphism screening of the exons containing previously reported nonsynonymous base substitutions was carried out by the polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) method, using genomic DNA from 81 Japanese patients with SLE and 207 healthy individuals. Two alleles were present in exon 6, coding for methionine (196M) and arginine (196R) at position 196. 30 of 81 patients (37.0%) with SLE were positive for the 196R allele, which was significantly more frequent compared with 39 of 207 healthy individuals (18.8%) (chi2=10.6, df=l, P=0.001, odds ratio=2.53, 95% CI: 1.45-4.43). Genotype analysis revealed that the presence of one 196R allele was sufficient for rendering susceptibility. The association of 196R allele with SLE was independent from that of HLA-DRB1*1501. In conclusion, the TNFR2 196R allele was found to be significantly associated with the susceptibility to SLE in the Japanese population. Further population and functional studies will be of particular importance to establish TNFR2 as one of the susceptibility genes to SLE.

Adolescent↗
PubMed1999

Allele typing of human TNFA 5'-flanking region using polymerase chain reaction-preferential homoduplex formation assay (PCR-PHFA): linkage disequilibrium with HLA class I and class II genes in Japanese.

Tumor necrosis factor alpha plays a substantial role in a number of conditions such as inflammation, autoimmunity, insulin resistance and sleep. Three new single nucleotide polymorphisms, -1,031 T/C, -863 C/A and -857 T/C, were recently identified in the upstream 5'-flanking region of TNFA in the Japanese population. In the present study, we developed polymerase chain reaction (PCR)-preferential homoduplex formation assay for the single-step allele typing of TNFA, and determined the genotypes of 271 healthy unrelated Japanese individuals. Four haplotypes, -1,031/-863/-857 TCC, TCT, CAC and CCC, were found to constitute the majority, if not all, of the TNFA alleles of healthy Japanese population. These alleles were designated as TNFA-U01, -U02 -U03 and -U04, respectively, in the order of frequency. Based on HLA-A, -B and -DRB1 genotypes together with TNFA genotypes, multi-locus haplotypes were analyzed. Significant positive associations were observed between TNFA-U01 and A*3303, B*5201, B*4403, B*4601, B*0702, DRB1*1502, DRB1*0101, DRB1*1302, between TNFA-U02 and B*5401, B*3501, DRB1*0405, DRB1*0407, between TNFA-U03 and B*4006, B*4002, DRB1*0803, DRB1*0802, DRB1*0403, DRB1*0901, and between TNFA-U04 and B*4801. Four-locus haplotype estimation revealed that A*3303-B*4403-TNFA-U01-DRB1*1302, A*2402-B*5201-TNFA-U01-DRB1*1502 and A*2402-B*5401-TNFA-U02-DRB1*0405 constitute major extended haplotypes in Japanese. Interestingly, TNFA alleles previously shown to have a higher promoter activity (U02, U03) were found to form haplotypes with certain DRB1 alleles associated with T helper 1 (Th1)-dominant diseases such as rheumatoid arthritis, insulin dependent diabetes mellitus and Crohn's disease in Japanese. In contrast, TNFA allele with a low promoter activity (U01) is in linkage disequilibrium with the DRB1 alleles associated with T helper 2 (Th2)-dominant diseases such as atopic dermatitis and ulcerative colitis. These observations raise the possibility that TNFA upstream promoter region polymorphisms contribute to some of the HLA-disease associations.

5' Untranslated Regions↗
PubMed1999

Lack of a strong association of CTLA-4 exon 1 polymorphism with the susceptibility to rheumatoid arthritis and systemic lupus erythematosus in Japanese: an association study using a novel variation screening method.

CTLA-4 is considered to be one of the attractive candidates for the susceptibility genes to rheumatic diseases. In the present study, the association of CTLA-4 polymorphism with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) was examined in the Japanese population using the case-control association analysis. Polymerase chain reaction-preferential homoduplex formation assay (PCR-PHFA) was applied for the screening of genetic variations and for the genotyping of a large number of samples. A greater proportion of Japanese patients with RA (44%) and SLE (44%) compared with healthy individuals (37%) had exon 1 49 G/G genotype, but the difference did not reach statistical significance. However, when the patients with RA and healthy individuals were stratified according to HLA-DRB1 alleles, a weakly significant increase of the positivity of CTLA-4 49G allele was observed in HLA-DRB1*0405-positive patients (87%) compared with DRB1*0405-positive healthy individuals (71%) (P = 0.014, odds ratio = 2.77). These results indicate that CTLA-4 exon 1 polymorphism does not contribute greatly to the susceptibility to RA and SLE, at least in Japanese, although the presence of CTLA4 49G allele could be a minor predisposing factor for RA in HLA-DRB1*0405-positive individuals. In addition, PCR-PHFA was shown to be useful for a mass screening of gene variations.

Abatacept↗
PubMed1999

New variations of human CC-chemokine receptors CCR3 and CCR4.

CCR3 and CCR4 are the members of CC chemokine receptor family expressed on Th2 type CD4+ T cells. In this study, variation screening of the entire coding regions of CCR3 and CCR4 was performed, and possible association with several autoimmune diseases was tested, using the genomic DNA from 304 Japanese healthy individuals and 272 Japanese patients with rheumatic diseases. One non-synonymous substitution was identified in CCR3 gene, whereas in CCR4 gene, two non-synonymous and two synonymous substitutions were detected. Among the synonymous substitutions, CCR4 1014(C-->T) was observed in 7.2% of the healthy individuals and 6.6% of the patients, and was considered as a single nucleotide polymorphism. All other variations were observed in only one or two individuals. No significant association was observed between any of the variations and any of the rheumatic diseases. Among these variations, CCR3-C218S substitution coded by 652(T-->A) substitution was localized in the region conserved among the G protein coupled receptor family. Reactivity of eosinophils to the monoclonal antibody against CCR3 and the chemotaxis to eotaxin were slightly reduced in this patient as compared with healthy controls or a patient with Behçet disease homozygous for the common allele, while CCR3 mRNA level was not different. These findings suggest that CCR3-C218S substitution may lead to the reduced function of CCR3 at the protein level. Further study will be of interest to test whether CCR3-C218S variation or any of the CCR4 variations has a significant role in rendering susceptibility to immunological diseases or resistance to HIV infection.

Alleles↗
PubMed1999

Association of Fc gamma receptor IIIB, but not of Fc gamma receptor IIA and IIIA polymorphisms with systemic lupus erythematosus in Japanese.

Human Fc gamma receptor (Fc gamma R) genes form a clustered gene family on chromosome 1q21-24. Although the association of Fc gamma R polymorphisms with systemic lupus erythematosus (SLE) has been extensively studied, the results are often contradictory. In this study, Fc gamma RIIA-131H/R, Fc gamma RIIIA-176F/V and Fc gamma RIIIB-NA1/2 genotypes were determined in the Japanese patients with SLE (n = 81) or rheumatoid arthritis (RA, n = 115) as well as in healthy individuals (n = 217), and possible association with the disease was tested using case-control analysis. Unlike in other populations, significant difference was not observed in the frequencies of Fc gamma RIIA and Fc gamma RIIIA genotypes between patients with SLE and healthy individuals. However, significant difference was detected in the frequencies of Fc gamma RIIIB genotypes between SLE and healthy individuals (P = 0.008). The odds ratio [OR] of the Fc gamma RIIIB-NA2/NA2 homozygotes for the development of SLE was 2.52 (95% confidence interval [CI]: 1.33-4.79). Among the patients with SLE, individuals with NA2/2 were significantly more likely to have lupus nephritis (P = 0.007). No association was observed between any of the Fc gamma R polymorphisms and RA. Significant linkage disequilibrium was detected between Fc gamma RIIIA and IIIB, but neither between IIA and IIIA, nor between IIA and IIIB. These observations may underscore the relevance of defective immune complex handling in the pathogenesis of SLE, or may suggest the presence of primarily associated gene(s) in linkage disequilibrium with Fc gamma R genes.

Adolescent↗
PubMed1999

Mitochondria in heart ischaemia and aging.

We have examined the effect of dietary polyunsaturated fatty acids (PUFAs) upon mitochondrial Ca2+ content and dehydrogenase activation in the rat heart. Diets were either a conventional low-fat chow (Ref) or were rich in n-3 PUFAs from fish oils (n-3) or n-6 PUFAs from animal fat (n-6). We found that the n-3 diet minimized the rise in mitochondrial Ca2+ seen in response to positive inotropic intervention with noradrenaline, and also minimized the activation of pyruvate dehydrogenase, which is Ca2+ dependent. As the work output of all three groups of hearts was the same, this observation may explain the previous finding of increased thermodynamic efficiency of the n-3 heart relative to the n-6 heart. When hearts were subjected to low-flow ischaemia (15 min), followed by 5 min of reperfusion, increases of mitochondrial Ca2+ were less in the n-3 group than in the n-6 group. In more prolonged ischaemia and reperfusion, n-3 feeding may confer protection against mitochondrial Ca2+ overload, opening of the permeability transition pore and cell death. Notably, the effects of n-3 feeding on mitochondrial functioning were most apparent in hearts from senescent rats (23 months). This is consistent with our finding that the decrease in mitochondrial membrane cardiolipin content, and increase in phosphatidylcholine, which occurred with aging in the Ref and n-6 groups, was totally prevented by n-3 feeding. Thus there are a number of reasons to regard an n-3-rich diet as being protective of the heart in aging mammals.

Aging↗
PubMed1999

Primary tumor of the ureteral stump following a nephrectomy for renal cell carcinoma.

BACKGROUND: A 64-year-old man presented with asymptomatic macroscopic hematuria during a follow up for a localized renal cell carcinoma (RCC), which was treated by a right radical nephrectomy 6 years earlier. METHODS: X-rays and a ureteroscopic examination revealed multiple papillary tumors filling the right ureteral stump. Surgery was performed to excise the ureteral stump and bladder cuff. The tumor was histologically a grade 2-3 transitional cell carcinoma without muscle invasion. RESULTS/CONCLUSIONS: Only four patients with a ureteral stump carcinoma, including the present case, have been reported after a nephrectomy for RCC. Considering that this patient had a past history of multiple cancers, genetic or environmental factors may have contributed to the etiology of the ureteral stump tumor.

Carcinoma, Renal Cell↗
PubMed1999

Combined effects of fabric air permeability and moisture absorption on clothing microclimate and subjective sensation during intermittent exercise at 27 degrees C.

The present paper aimed at determining the combined effects of two different levels of air permeability and moisture absorption, in terms of clothing microclimate and subjective sensation, in resting and exercising subjects at an ambient temperature of 27 degrees C, a relative humidity of 50% and an air velocity of 0.14 m s-1. Three kinds of clothing ensemble were investigated: (1) polyester clothing with low moisture absorption and low air permeability (A), (2) polyester clothing with low moisture absorption and high air permeability (B), and (3) cotton clothing with high moisture absorption and high air permeability (C). The subjects exercised for 10 min on a cycle ergometer at an intensity of 30% maximal oxygen uptake and then had a 10 min rest. This sequence was repeated four times. The main findings are summarized as follows: (1) The clothing microclimate humidity in the back area was significantly higher in A than in B, and in C than in B. (2) The clothing microclimate temperature in the chest area was significantly higher in B than in A, and in B than in C. (3) The clothing microclimate temperature in the back area was significantly higher in C than in B. (4) The clothing surface temperature was significantly higher in C than in B. (5) Although the positive relationships between the microclimate humidity and forearm sweat rate was significantly confirmed in all three kinds of clothing, the microclimate humidity at chest for the same sweat rate was lower in C than in A and B. (6) Although the positive relationships between subjective sensation and forearm sweat rates were significantly confirmed in all three kinds of clothing, the subjective discomfort seemed to be reduced more effectively in C than in A and B for the same sweat rate. These results were discussed in terms of thermal physiology and combined effects of air permeability and moisture absorbency of the fabrics.

Absorption↗
PubMed1999

Increased serum levels of vascular endothelial growth factor in patients with renal cell carcinoma.

Neovascularization, an essential event for the growth of solid tumors, is regulated by a number of angiogenic factors. One such factor, vascular endothelial growth factor (VEGF), is considered to exert a potent angiogenic activity, as indicated by immunohistochemical and molecular evidence. In this study we investigated the serum VEGF level (s-VEGF) in patients with renal cell carcinoma (RCC). s-VEGF in peripheral blood samples was analyzed in 40 RCC patients and 40 patients without cancer (controls) using a sandwich enzyme-linked immunoassay. In 20 RCC patients, serum samples were obtained separately from the bilateral renal veins. s-VEGF was also measured before, 4 and 8 weeks after nephrectomy in 11 patients. There were significant differences in s-VEGF between the RCC patients and the controls (207.3+/-32.9 vs. 71.5+/-9.1 pg/ml, mean+/-SE) (P<0.005), between the tumor-bearing renal veins and the contralateral ones (P<0.01), between the pre- and post-nephrectomy situations (P<0.01) and among the various parameters of tumor status such as tumor extent (P<0.001) and existence of metastasis (P<0.001). s-VEGF significantly correlated with the tumor volume obtained by a three-dimensional measurement (r=0.802, P<0.0001). The sensitivity and specificity of s-VEGF at the cut-off level of 100 pg/ml, as determined by the receiver-operating-characteristics curve, were 80.0% and 72.5%, respectively. The results indicate that tumor tissue of RCC liberates VEGF into the systemic blood flow and that s-VEGF is a possible marker for RCC.

Adult↗
PubMed1999

PUFA and aging modulate cardiac mitochondrial membrane lipid composition and Ca2+ activation of PDH.

Aberrations in cell Ca2+ homeostasis have been known to parallel both changes in membrane lipid composition and aging. Previous work has shown that the lowered efficiency of work performance, which occurs in isolated hearts from rats fed a diet rich in n-6 polyunsaturated fatty acids (PUFA), relative to those fed n-3 PUFA, could be raised by mitochondrial (Mito) Ca2+ transport inhibition. We tested whether, after Ca2+-dependent stress, the Ca2+-dependent activation of pyruvate dehydrogenase (PDHA/PDHTotal) and Mito Ca2+ cycling could be manipulated by varying the ratio of n-3 to n-6 PUFA in Mito membranes in young (6 mo) and aged (24 mo) isolated rat hearts treated to n-3 or n-6 PUFA-rich diet. Inotropic stimulation by 1 microM norepinephrine (NE) of 24-mo n-6 PUFA-rich hearts elevated total Mito Ca2+ content 38% more than in 6-mo hearts (P < 0. 05). However, both the NE-induced rise in Mito Ca2+ and the difference in response between 6- and 24-mo hearts were partially abolished by n-3 PUFA treatment. NE increased the fractional activation of PDH by 44% above control levels in the 6-mo group compared with 49% in the 24-mo group after n-6 PUFA diet. However, NE stimulation of PDHA was attenuated by n-3 PUFA diet, attaining values only 29 and 23% above control levels in 6- and 24-mo mitochondria, respectively (P < 0.05). Global ischemia and reperfusion (I/R) in n-6 PUFA hearts gave rise to higher levels of total Mito Ca2+ concentration (P < 0.0001) and PDHA (P < 0.0001) compared with n-3 PUFA. Ruthenium red (3.4 microM) abolished the effects of I/R in all groups. With aging, heart Mito membrane phosphatidylcholine was increased after n-6 PUFA-rich diet (by approximately 15%, P < 0.05), whereas cardiolipin and n-3 PUFA content were diminished by 31% (P < 0.05) and 73% (P < 0.05), respectively. These effects were prevented by n-3 PUFA-rich diet. The present study, by directly manipulating the cardiac Mito membrane n-3-to-n-6 PUFA ratio, shows that the activation of Ca2+-dependent PDH can be augmented when the n-3-to-n-6 PUFA ratio is low (n-6 PUFA-rich diet; 24-mo hearts) or attenuated when this ratio is relatively high (n-3 PUFA-rich diet). We propose that one of the consequences of dietary-induced manipulation of membrane phospholipids and PUFAs may be the altered flux of Ca2+ across the Mito membrane and thus altered intramitochondrial Ca2+-dependent processes.

Aging↗
PubMed1999

[Analysis of susceptibility genes to rheumatic diseases].

Recent evidence suggests that most of the rheumatic diseases are complex or multifactorial diseases with contributions from HLA and multiple non-HLA genes. Studies using candidate gene approach suggested that early components of the complement pathway, Fc receptor IIa, IIIa, mannose-binding lectin, IL-10 and TNFR2 might be potential non-HLA susceptibility genes to systemic lupus erythematosus, although substantial difference among populations are reported. Linkage analyses using affected sib pairs indicated several candidate regions on chromosome 1. A recently completed genome-wide linkage analysis of rheumatoid arthritis revealed a number of possible candidate regions in addition to HLA. Identification of the susceptibility genes will be accelerated along with technological advances and the accomplishment of human genome project, and will deepen our understanding of rheumatic diseases.

Genetic Predisposition to Disease↗