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K Tadokoro

Publications and source records attributed to K Tadokoro.

At least 109 records · Page 6Linked to original sources
PubMed1996

Large-scale DNA typing for human platelet alloantigens by PCR-PHFA (preferential homoduplex formation assay).

Alloimmunization against human platelet alloantigens (HPA) is known to be involved in disorders such as neonatal alloimmune thrombocytopenic purpura, posttransfusion purpura, and refractoriness to platelet transfusion therapy. HPA typing is essential in diagnosis and management of patients. Therefore a reliable and speedy method is necessary for HPA typing. We have successfully applied a new DNA typing method, PCR-preferential homoduplex formation assay (PHFA) method, to typing for the HPA-1, -2, -3, -4, -5 and -6 systems. This method is based on DNA strand competition during hybridization under a precisely controlled temperature gradient between a double-labelled amplicon (standard DNA), prepared from biotin- and DNP-labelled primers, and an unlabelled amplicon (sample DNA). The results obtained by PCR-PHFA typing were in good agreement with the allotypes determined by serological typing and by other DNA typing methods. The PCR-PHFA method can be easily automated, is suitable for typing both small and large numbers of samples, and thus is applicable to routine HPA typing.

Antigens, Human Platelet↗
PubMed1996

A unique origin and multistep process for the generation of expanded DRPLA triplet repeats.

Dentatorubral and pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder associated with the expansion of a CAG repeat at chromosome band 12p13. Epidemiological studies have demonstrated an increased prevalence of DRPLA in Japan, although several DRPLA kindreds of non-Japanese ancestry have been identified. To define the molecular basis for this geographic variation in prevalence, we have analyzed haplotypes around the repeat in several different ethnic groups. Two intragenic biallelic polymorphisms distinguished three haplotypes, each of which formed a predominant haplotype found in the three major racial populations. All the expanded repeats of Japanese and Caucasian patients studied were associated with a particular haplotype, which otherwise was associated with longer repeats commonly found in Asians. Our results support a multi-step model for repeat expansion, and suggest that expanded DRPLA repeats may have evolved from an ancient chromosomal haplotype of Asian origin. We also propose that a combination of a highly polymorphic microsatellite marker with relatively stable biallelic markers in a range of PCR amplification is a powerful tool for studies on human genome diversity, which may reveal the ancient human migration and the formation of ethnic groups.

Black or African American↗
PubMed1996

Effects of interleukin (IL)-3 and IL-5 on human eosinophil degranulation induced by complement components C3a and C5a.

It is suggested that eosinophils (Eos) play an important role in the pathogenesis of bronchial asthma by releasing cytotoxic cationic eosinophil granule proteins and damaging bronchial epithelial cells. However, the exact nature of the actual inducer of eosinophil degranulation in vivo is unclear. We examined eosinophil cationic protein (ECP) release from human Eos in response to soluble agonists such as C5a, C3a, platelet-activating factor, and FMLP with or without interleukin (IL)-3 or IL-5 priming. Eosinophil degranulation induced by these soluble agonists required the pretreatment of Eos by cytochalasin B even in IL-3 priming. Among four agonists, C5a was the most effective stimulus of ECP release either with or without IL-5 priming. IL-3 and IL-5 remarkably enhanced ECP release in Eos triggered by C3a and C5a. The enhancement of ECP release by IL-3 and IL-5 occurred at 0.1-0.3 ng/ml and became maximal at 10-30 ng/ml, concentration-dependently. The enhancement of ECP release by cytokines became optimal at an interval of 10 min. Our data support the importance of complement components and cytokines in eosinophil degranulation in vivo.

Blood Proteins↗
PubMed1996

Further molecular diversity in the HLA-B15 group.

In order to further clarify the diversity of the HLA-B15 antigens and the correspondence of serological types with alleles in Asians, we screened various B15 serological splits by means of a polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method. Subsequently, the genes encoding various B15 variants were sequenced. Two novel alleles, B*1528 and B*1529, were identified: the nucleotide sequence of the former contained a single-base substitution at position 263 in exon 2 as compared to that of the B*1501 allele, which results in an amino acid change at position 64 in the alpha 1 domain, and the nucleotide sequence of the latter differs from that of B*1518 by a single-base substitution at position 272 of exon 2 which results in an amino acid change at position 67 of the alpha 1 domain. One new allele, B*1521, described recently in Australian Aborigines was also identified in Asians in the present study. Moreover, the results of sequencing demonstrated that Asian HLA-B62, B70, and B77 antigens are encoded by B*1501, B*1518, and B*1513, respectively. Two splits of B75 antigens, B75V (TS-1) and B15N, which have been proposed to exist in the Japanese population were encoded by B*1511 and B*1502, respectively. Most of the B15 alleles detected in the present study showed positive associations with other locus antigens. Especially, B*1502 was strongly associated with Cw8, while B*1521 was strongly associated with A34 and Cw6.

Alleles↗
PubMed1996

Enhancement of the expression of progesterone receptor on progesterone-treated lymphocytes after immunotherapy in unexplained recurrent spontaneous abortion.

PROBLEM: The immunological mechanism of an effective immunotherapy with paternal lymphocytes for unexplained recurrent spontaneous abortion (RSA) is not yet clear. Previous studies revealed that progesterone plays an important role in maintaining normal pregnancy and lower expression of progesterone receptor (PGR) on lymphocytes was found in RSA. Therefore, it was of interest to investigate whether immunotherapy for RSA would be able to enhance the expression of PGR on lymphocytes of RSA. METHOD: PGR expression on lymphocytes was analyzed with indirect immunofluorescence using flow cytometry. RESULTS: There was no change of PGR expression on PBL of RSA between pre- and post-immunotherapy (P > 0.05), while in the presence of 10.0 micrograms/ml progesterone for 24 h, PGR expressed on PBL on post-immunotherapy was increased significantly as compared with that of pre-immunotherapy in successful cases (P < 0.05) and decreased in abortive cases (P < 0.05). Most PGR was expressed on both CD4+ and CD8+ lymphocyte subsets. In successful cases, CD8+PGR+ subset of post-immunotherapy was found to be increased significantly (P < 0.05) in comparison with that of pre-immunotherapy. CONCLUSION: The data in the present study suggest that immunotherapy for RSA induced a higher expression of PGR on progesterone-treated lymphocytes, which may be involved in successful pregnancy.

Abortion, Habitual↗
PubMed1996

HLA-G gene polymorphism in a Japanese population.

Polymorphism of the HLA-G gene in a Japanese population was investigated employing polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) analysis, PCR sequence-specific oligonucleotide (SSO) analysis, and DNA direct sequencing. Nucleotide sequence variations in exons 2, 3, and 4 of the HLA-G gene in 54 healthy Japanese individuals were examined. In addition, seven Japanese samples carrying common HLA haplotypes were analyzed. In total, nine single-base substitutions compared with the sequence of G*01011 were identified: one in intron 1 (nucleotide position 970), one in exon 2 (the third base of codon 57: G --> A), three in intron 2 (1264, 1276, and 1292), three in exon 3 (the third base of codon 93: C --> T, the third base of codon 107: A --> T, and the first base of codon 110: C --> A), and one in intron 3 (2334). The substitution at codon 110 was non-synonymous and led to an amino acid substitution from leucine to isoleucine. The other three nucleotide substitutions in exons were synonymous. Through analysis of combinations of the exon 2, 3, and 4 nucleotide sequences we identified four alleles, which we provisionally designated GJ1, GJ2, GJ3, and GJ4. The allele frequencies were estimated to be 0.33, 0.16, 0.45, and 0.06, respectively. Nucleotide sequences of GJ1, GJ2, and GJ4 were identical to G*01011, the clone 7.0E, and G*01013, respectively. GJ3 was a newly observed allele and was officially designated G*0104 by the WHO Nomenclature Committee in January 1996. Strong positive associations were observed between HLA-G alleles and HLA-A, -B, or -DRB1 alleles.

Alleles↗
PubMed1996

HLA-B27 subtypes in Japanese with seronegative spondyloarthropathies and healthy controls.

OBJECTIVE: To determine HLA-B27 subtype frequencies in Japanese patients with seronegative spondyloarthropathies (SpA) and healthy controls. METHODS: We determined HLA-B27 subtypes of 20 Japanese patients with ankylosing spondylitis and one with Reiter's syndrome, and 11 healthy Japanese individuals using a polymerase chain reaction sequence specific oligonucleotide hybridization method specifically designed for the discrimination of B*2701-09. RESULTS: 14 of 21 (67%) patients and 9 of 11 (82%) controls were typed as B*2704. The remainder were B*2705. CONCLUSION: HLA-B*2704 and B*2705 are present in the Japanese population, the former being the predominant subtype of HLA-B27. Both subtypes are associated with SpA.

Asian People↗
PubMed1996

[Trials and analysis of umbilical cord blood collection, separation and cryopreservation methods for transplantation].

Placental and umbilical cord blood, as an alternative course of haematopoietic stem cells for bone marrow reconstitution, have recently been showed to yield successful sibling-donor cord blood grafts children. The advantages of using cord blood are related to the high number of haematopoietic progenitors in circulation at birth. In our study there was a remarkable heterogeneity of volume, number of nucleated cells and the number of progenitors from sample to sample. Seven out of 40 samples of more than 61 ml blood volume contained 1.8 (+/- 1.0) x 10(5) CFU-GM or 6.0 (+/- 4.8) x 10(8) nucleated cells. 10 ml of whole blood was necessary for laboratory tests including ABO blood type, screening of infectious markers, HLA typing, as well as frozen sera and cells for the possible future tests. Collected cord blood of more than 70ml in volume may have sufficient numbers of CFU-GM for engraftment to pediatric patients weighing about 20 kg. A cord blood bank project is now going on by collecting blood with informed consent of the mother in cooperation with obstetrics and gynecology staff.

ABO Blood-Group System↗
PubMed1995

Family segregation analysis of inheritance of human minor histocompatibility antigen.

Disparities in minor histocompatibility antigens (mHAs) between HLA-identical donor and recipient pairs often cause graft-versus-host disease (GVHD) or graft rejection. Minor HAs are thought to be peptides that are associated with specific major histocompatibility complex (MHC) molecules and are presented to specific T cells. Despite the importance of mHAs in constructing a strong immunological barrier following tissue transplantation, little information on mHAs in humans is available. We have already reported establishment of the DR9-restricted mHA-specific CD4+ cytotoxic T cell (CTL) clone "A-6." To investigate the chromosomal localization of the gene encoding the mHA peptide recognized by clone A-6 in context with DR9, we performed a family segregation analysis. We concluded that the mHA-encoding gene was transmitted from parent(s) to some offspring.

B-Lymphocytes↗
PubMed1995

Prevalence of Borna disease virus RNA in peripheral blood mononuclear cells from blood donors.

The presence of Borna disease virus (BDV) in peripheral blood mononuclear cells (PBMC) of 100 blood donors from Sapporo and 72 blood donors from Tokyo was examined using nested reverse transcriptase/polymerase chain reaction amplification with specific-primers for BDV p24. Anti-BDV p24 antibodies in the plasma of the 100 blood donors from Sapporo also were studied by enzyme-linked immunosorbent assay and by Western blot. BDV RNA was detected in 3 (4.2%) of the 72 PBMC samples from Tokyo, and in 5 (5%) of the 100 PBMC samples from Sapporo. In contrast, anti-p24 antibodies were found in only 1 (1%) of the donors from Sapporo. These results suggest that BDV infection in humans may be more widespread than previously thought.

Adolescent↗
PubMed1995

A new B18 sequence (B*1802) from Asian individuals.

A new HLA-B18 allele (B*1802) derived from a Thai individual was sequenced. Comparison of this B18 nucleotide sequence with the published B*1801 sequence indicated that this Asian B18 allele has a nucleotide sequence different from that of B*1801. Three nucleotide changes were observed in exon 3, in which two substitutions at codon 97, AGG in B*1801 to AAT in the B*1802, result in an amino acid change from arginine to asparagine. The residue 97Asn has also been described in some B27 subtypes. A silent mutation was also observed at codon 99, TAC in B*1801 to TAT in the B*1802. This sequence has been reported in many class I alleles published so far. Moreover, 18 HLA-B18-positive samples were examined by the PCR-SSO method using specific probes for B*1801 and B*1802. The results demonstrated that three Asian samples possess B*1802 and share HLA-Cw7, DR12, and DQ7.

Alleles↗
PubMed1995

A new HLA-A9 subtype lacking the Bw4 epitope. Ancestral or revertant allele?

The HLA-A9 group has been subdivided into three serologically defined splits, A23, A24, and A2403. We have found a new HLA-A9 split antigen, tentatively called A24AK, in the Japanese population. Sequence analysis of A24AK (officially assigned A*2404) showed that this new allele was different from HLA-A*2402, which codes for the common A24 antigen, by seven nucleotides, and the two alleles could be discriminated by the PCR-SSCP method. These nucleotide substitutions are predicted to result in substitution of six amino acid residues at positions 76, 79, 80, 81, 82, and 83. In all HLA-A9-group alleles described to date, this region is known to code for the Bw4 epitope, which is usually localized on HLA-B molecules. However, the new allele lacks the Bw4 coding sequence. Sequencing results are supported by results showing that the lymphocytes from A24AK-positive individuals did not react with anti-Bw4 antiserum. The nucleotide sequence of A*2404 in this region was identical to that of A*0101, A*2601, A*2602, and several other alleles. These findings suggest several possible paths of evolution of this new allele.

Alleles↗
PubMed1995

High-resolution HLA-DQB1 typing by combination of group-specific amplification and restriction fragment length polymorphism.

A reliable method for high-resolution HLA-DQB1 typing using the combination of group-specific amplification and RFLP analysis is described. Group-specific amplification was carried out for the alleles of two groups using the two primer pairs under the same PCR conditions. One group contains DQ5 and DQ6 specificities and the other DQ2, DQ3, and DQ4 specificities. Computer analysis on cleavage patterns for 19 alleles of the DQB1 gene showed that the 11 alleles of the former group could be distinguished with five restriction enzymes and the eight alleles of the latter group could be distinguished with four enzymes. We could reduce the number of restriction endonucleases required compared with the number used in previous studies because we selected appropriate restriction enzymes which had at least one recognition site in almost all DQB1 alleles as a form of internal control. Moreover, DQB1*0602 and 0603, which were indistinguishable using the previously reported PCR-RFLP methods, could be distinguished by the present method. The results of typing of 100 samples from Japanese individuals by this method showed no discrepancy with the results obtained by serologic methods. The calculated allele frequencies showed good agreement with those reported at the 11th International Histocompatibility Workshop.

Base Sequence↗
PubMed1995

Sequence-based typing of HLA-A2 alleles using a primer with an extra base mismatch.

A PCR-SBT method using genomic DNA for HLA-A2 alleles was established. To achieve specific amplification for detecting a single base difference between A2 alleles and other HLA-A alleles, a primer having one extra mismatch at the second position from its 3'-end was designed. The primer exhibited a high specificity with annealing temperatures from 64 degrees C to 68 degrees C. Thirty-eight Japanese samples were screened using this method. The majority of Japanese A2 antigens were coded by A*0201. A*0206 and A*0207 were observed at relatively high frequencies. Serologically defined split antigens, A2S and A2AK, which we have recently identified, corresponded to A*0203 and A*0210, respectively. Moreover, A*0207 was strongly associated with B46 and DR8.1.

Alleles↗
PubMed1995

Both HLA-B*1301 and B*1302 exist in Asian populations and are associated with different haplotypes.

A B13 split antigen was newly identified with three alloantisera in Japanese, and two B13 split antigens were found in a Thai family. To confirm the variation of B13 and understand the correspondence between the serologic splits and the published B13 alleles, B*1301 and B*1302, we determined the sequences of genes coding for these B13 splits. The common Japanese B13 allele was found to be B*1301, whereas another split antigen was shown to be coded by B*1302. Two B13 variants identified in a Thai individual corresponded to B*1301 and B*1302. Moreover, 57 B13-positive samples from several ethnic groups were examined using the PCR-SSO method. Differing from previous reports, both B*1301 and B*1302 were found in samples from Asian populations. These two alleles were separately associated with different antigens: HLA-B*1301 exhibited a strong association with A2, Cw10, DR12, and DQ7 antigens, whereas HLA-B*1302 was strongly associated with A30, Cw6, DR7, and DQ2 antigens. In addition, applying the PCR-SSCP method, B*1301 and B*1302 could also be simply distinguished from each other.

Alleles↗