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Biomedical subjects

Y Hidaka

Publications and source records attributed to Y Hidaka.

At least 91 records · Page 5Linked to original sources
PubMed1996

Expression of thyroid peroxidase in EBV-transformed B cell lines using adenovirus.

Thyroid peroxidase (TPO) is thought to be one of the pathological antigens in Hashimoto's thyroiditis. Epstein-Barr virus-transformed B cell lines (EBVL) can be used for antigen-presenting cells and target cells of cytotoxic T cells. To develop a model for endogenous TPO presentation in EBVL, we constructed a recombinant adenovirus carrying the TPO gene driven by the cytomegalovirus promoter (Ad5-TPO). Enzymatically active human TPO could be expressed in COS cells using Ad5-TPO. the peroxidase activity of the membrane extract from Ad5-TPO-infected COS cells was approximately 6 times higher than that from stably transfected TPO expressing CHO cells. TPO protein expression in the EBVL was analyzed by Western blotting technique. A band at approximately 110 kDa characteristic of hTPO was detected in EBVL infected with Ad5-TPO. hTPO expression in EBVL induced with adenovirus should facilitate understanding of T cell immunity to TPO in patients with autoimmune thyroid diseases.

Adenoviridae↗
PubMed1996

Onset of Graves' thyrotoxicosis after an attack of allergic rhinitis.

We previously reported that allergic rhinitis was an aggravating factor for Graves' disease and that thyrotoxicosis relapsed 2 months after an allergic attack. In this paper, we report a patient who showed onset of Graves' thyrotoxicosis after an attack of allergic rhinitis. The patient, a 30-year-old woman, was initially diagnosed with subclinical autoimmune thyroiditis. Interestingly, the patient showed weak activity of thyroid-stimulating antibody (TSAb), while TSH-binding inhibitory immunoglobulin (TBII) was negative and her thyroid function tests, including TSH, were completely normal. The patient developed severe allergic rhinitis in response to Japanese cedar pollen lasting from February until April in 1995 with an increase in serum antigen-specific immunoglobulin E and peripheral blood eosinophils. Two months later, she developed thyrotoxicosis in association with increase in TSAb and TBII. These findings suggest that allergic rhinitis not only aggravates Graves' disease but also induces the clinical onset of Graves' thyrotoxicosis.

Adult↗
PubMed1996

Changes in soluble CD4 and CD8 proteins in healthy pregnant and postpartum women.

PROBLEM: We examined physiological changes in serum levels of soluble CD4 (sCD4) and soluble CD8 (sCD8) during pregnancy and 1-12 months postpartum to study changes in the maternal immune system during and after pregnancy. METHOD: The serum concentrations of sCD4 and sCD8 were measured by enzyme immunoassay in the sera separated from blood samples withdrawn from healthy women in the 1st, 2nd, and 3rd trimesters of pregnancy and 1, 4, 7, and 10-12 months postpartum (n = 182) and healthy non-pregnant women (n = 25), and in 90 of the women, the changes in sCD4 and sCD8 were compared with changes in the number of peripheral CD4+ and CD8+ cells measured by flow cytometry. RESULTS: The serum concentration of sCD4 decreased throughout pregnancy, from the first trimester, and recovered gradually after delivery. The serum concentration of sCD8 did not change significantly during or after pregnancy compared to the concentration in the non-pregnant controls, but the concentration 1 month postpartum was significantly higher than that in the 3rd trimester. The number of CD4+ and cd8+ cells decreased during pregnancy but did not change significantly after delivery. Interestingly, the ratio of the serum sCD4 level to the number of CD4+ cells decreased and the ratio of the sCD8 level to the number of CD8+ cells increased in the first and second trimesters of pregnancy, but these ratios were within the normal range from the third trimester of pregnancy to 10-12 months postpartum. CONCLUSIONS: Decreases in serum sCD4 concentration and in the ratio sCD4/CD4+ cells, and an increase in the ratio sCD8/CD8+ cells may be important factors in the immunological changes that occur during pregnancy.

Adult↗
PubMed1996

Identification of ligand recognition sites in heat-stable enterotoxin receptor, membrane-associated guanylyl cyclase C by site-directed mutational analysis.

Guanylyl cyclase C (STaR), a receptor protein for heat-stable enterotoxin (STa) elaborated by Escherichia coli, is associated with and spans the plasma membrane of mammalian intestinal cells. The extracellular domain functions in the binding of STa and the association of each domain to an oligomeric form. Two amino acid residues, Arg-136 and Asp-347, were identified as the residues binding to STa in the extracellular domain of pig STaR by site-directed mutagenesis and analysis of expression on 293T cells. Replacement of these residues by other amino acid residues resulted in the loss of binding of pig STaR to STa, and as a result, STa-induced guanylyl cyclase activity was eliminated. Furthermore, mutation in a region (from Asp-347 to Val-401) which is close to the transmembrane domain caused a significant reduction in both STa-binding activity and guanylyl cyclase catalytic activity. These results suggest that the region adjacent to the transmembrane domain plays an important role in facilitating a favorable conformation of STaR for STa binding.

Animals↗
PubMed1996

[High prevalence of hcv infection in a town where high mortality from liver disease is observed].

It was recognized that the mortality rate from chronic liver diseases in town T was greater than 2 times the average for other areas of Miyazaki Prefecture. A seroepidemiological survey of the hepatitis viral markers, such as, HBs antigen (RPHA method) and CP antibody (EIA method) an HCV core antibody, was conducted among 7,178 residents both in town T and in its neighboring town Y. There was no difference in the rates of HBs antigen positives between town T (1.1%) and town Y (0.9%). However, the rates of CP antibody positives were 23.7% and 2.7% in town T and town Y, respectively. The former was significantly higher than the latter (p < 0.001, Chisquare test). CP antibody positives are more likely to have abnormal liver function than negatives. These results clearly suggest that the rate of the residents with abnormal levels of liver function in town T was significantly higher than in town Y. Of 33 people who had a history of acute hepatitis in 1972, 30 tested positive for CP antibody. An epidemic of acute hepatitis in 1972 is speculated to have been caused by HCV infection, which in turn may account for the higher incidence of liver disease mortality in town T.

Adolescent↗
PubMed1996

[Discrepancy of platelet numbers between automated blood cell analysis and manual counting in the patients with thrombocytopenia].

Automated blood cell analyzer can measure the numbers of blood cell and a histogram patterns of WBC, RBC and Platelet (PLT), and calculate the blood cell indices (RDW, MPV, PDW, etc). It is important clinically in the patients with thrombocytopenia (below 10 x 10(4)/microliter) to measure correct platelet number. However platelet number with automated blood cell analyzer was influenced by the changes in erythrocyte morphology or various PLT conditions. We subclassified the patients with thrombocytopenia into 5 groups according to the histogram pattern of PLT, and compared platelet numbers among NE-8000 analysis (Sysmex), H*2 analysis (Bayer's) and manual method in each group. In the group of abnormal histogram pattern of PLT, platelet numbers obtained with NE-8000 or H*2 were significantly low comparing to manual numbers. About 70% of samples of which Platelet Distribution Width (PDW) was abnormal showed discrepant values between automated analysis and manual eye count. In conclusion, discrepant low platelet count would be obtained by automated analysis and therefore should be carefully interpreted in the patients with thrombocytopenia and abnormal platelet histogram pattern.

Automation↗
PubMed1996

[Gene therapy for genetic disorders of purine metabolism].

Anderson proposed three genetic diseases deficient in enzymes involved in purine metabolism as candidate for human gene therapy in 1984. Over the past ten years, marked advances in molecular genetics have brought gene therapy to reality. Gene therapy for ADA deficiency was performedin the United States in 1990 and in Japan in 1995 as the first trial. Basic study for HPRT gene transfer has been proceeding toward gene therapy for HPRT deficiency despite the difficulties in gene transfer into the nervous systems.

Adenosine Deaminase↗
PubMed1995

Production of thyroid-stimulating antibodies in mice by immunization with T-cell epitopes of human thyrotropin receptor.

We examined whether mice, immunized with TSH receptor (TSH-R) peptides, which are known to be T-cell epitopes in patients with Graves' disease, would show thyroid-stimulating antibody (TSAb). We immunized DBA/1J mice with TSH-R peptide amino acids 132-150, 145-163, 158-176, and 172-186 and with a pool of these four peptides. The antibodies produced in these mice were evaluated by measurement of TSAb activity using Chinese hamster ovary cells expressing human TSH-R. Seven of 20 mice showed TSAb activity that could be partially blocked with TSH-R peptides. To assess the role of T-cell epitope-specific T-cells in the production of TSAb, we transferred a T-cell line developed from a TSAb-positive mouse to other syngeneic DBA/1J mice. Two of 4 recipient mice showed TSAb activities. These findings suggest that specific T-cell epitopes of TSH-R play a crucial role in the production of TSAb.

Amino Acid Sequence↗
PubMed1995

CTLA-4 gene polymorphism associated with Graves' disease in a Caucasian population.

Graves' disease (GD) is an autoimmune thyroid disease. Multiple genetic factors are believed to be involved in its pathogenesis, but the factors are largely unknown, except for sex (female disease preponderance) and the role of human leukocyte antigen (HLA) genes on chromosome 6. To understand the mechanisms underlying the development of GD, a search for non-HLA-linked genes is crucial, and we tested several candidate genes, including the CTLA-4 gene on chromosome 2q33. CTLA-4 molecules may either facilitate or down-regulate the second signal to T-cells, which is provided by the interaction between the two accessory molecules CD28 and B7. One hundred and thirty-three Caucasian patients (26 males) with GD and 85 local controls were included in this study. Polymerase chain reaction was used to amplify DNA containing the (AT)n repeat within the 3'-untranslated region of exon 3 of the CTLA-4 gene. The 5'-forward primer was radiolabeled, and amplified products were resolved on 5-7% sequencing gels. All subjects were previously typed for HLA class II alleles. Twenty-one alleles were observed with sizes ranging from 88-134 basepairs. In the association analysis, the genotype frequencies between GD patients and controls differed significantly (P = 0.012), and the difference was attributable to a higher frequency of the 106-basepair allele among patients (relative risk, 2.82). When the patients were subdivided with respect to sex and HLA, the phenotype frequencies of allele 106 was higher in the female patients with protective HLA specificities (DQA1*0201 positive/DQA1*0501 negative) than in those with susceptible HLA specificities (DQA1*0201 negative/DQA1*0501 positive; 81.8% vs. 45.5%; P = 0.026). The CTLA-4 gene or a closely associated gene (including CD28) confers susceptibility to GD. This association may be more important in female patients with protective HLA specificities, who otherwise would be at low risk of developing the disease.

Abatacept↗
PubMed1995

Graves' disease in severe combined immunodeficient mice.

Graves' disease (GD) is an autoimmune thyroid disorder involving an antibody (TSAb) directed against the TSH receptor (TSHR) producing thyroid stimulation. We have developed an animal model of GD by engrafting peripheral blood mononuclear cells or T cell lines plus autologous thyroid tissue into severe combined immunodeficient (SCID) mice. We xenografted Graves' thyroid tissue from six patients into six groups of SCID mice. Autologous PBMC and T cell lines reactive to recombinant human TSHR extracellular domain and non-TSHR lines were injected ip into the designated groups. In some of the studies, thyroid tissue was irradiated with 2000 rads before xenografting. Irradiation of xenografts induced thyroid tissue damage and release of thyroid antigens and hormones. Mice reconstituted with peripheral blood mononuclear cells or nonspecific T cell lines did not simulate GD. However, we achieved production of TSAb, elevation of serum T3, and TSAb-dependent survival and function of human Graves' thyroid tissue in SCID mice reconstituted with TSHR-specific T cell lines. We reconstituted SCID mice with PBMC and TSHR-specific T cell lines that recognized TSHR peptide 158-176. This may be in vivo evidence of the importance of peptide 158-176 as an immunodominant epitope on the TSHR extracellular domain.

Adult↗
PubMed1995

T-cells recognize multiple epitopes in the human thyrotropin receptor extracellular domain.

In Graves' disease (GD), the TSH receptor (TSHR) is believed to be the major target of an autoimmune response. T-Lymphocytes regulate the immune system. To assess the interaction of T-cells with TSHR in the pathogenesis of GD, we tested the T-cell response of peripheral blood mononuclear cells and T-cell lines to the recombinant human TSHR extracellular domain (rhTSHR-ECD) and 31 synthetic peptides corresponding to the entire TSHR-ECD in 20 patients with GD, 8 patients with Hashimoto's thyroiditis, 7 with colloid nodular goiter (CNG), and 20 normal controls. Comparing patients from different groups with normal subjects, there was a significant response to rhTSHR-ECD and thyroglobulin in GD patients (P < 0.001) and HT patients (P < 0.05), but not in CNG patients (P > 0.1). All 20 patients with GD responded to at least one peptide. The reactivity in GD patients was heterogeneous and spanned the entire TSHR-ECD. However, the reactivity was significantly different from that in controls for peptide regions 44-88, 119-176, 227-263, and 343-376, and the stimulation index (SI) values were significantly different for peptides 272-291 and 301-320. Significant differences were confined to peptides 158-176 and 343-362 and the region 227-263 for comparison of the number of positive responses in patients and controls to individual peptides. Forty-six percent of human leukocyte antigen-DQA1 0501 allele-positive Graves' patients responded to peptides 158-176 and 248-263 (SI = 3 or more) compared to 14% of allele-negative patients. In HT and CNG patients, the response was mainly to peptides in the carboxy-terminal half of the TSHR-ECD. Concordance of the reactivity in T-cell lines and peripheral blood mononuclear cells was observed in 36% of direct comparisons in GD. Eighty-five percent and 90% of GD patients were positive for microsomal antibody and TSHR antibody, respectively, and 59% of microsomal antibody-positive and 67% of TSHR antibody-positive patients responded to rhTSHR-ECD (SI = 2 or more). However, there was no significant correlation between antibody-positive patients and reactivity to specific peptides. Using multiple criteria to define immunodominance, peptides 158-176, 237-252, 248-263, and 343-362 seem to be important epitopes and may be critical for T-cell triggering in GD.

Adult↗