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Biomedical subjects

T Kohsaka

Publications and source records attributed to T Kohsaka.

At least 91 records · Page 5Linked to original sources

Differential regulation of interleukin-6 production in the kidney by the renal sympathetic nerves in normal and spontaneously hypertensive rats.

OBJECTIVE: The aim of the study was to evaluate the influence of renal sympathetic nerves on the production of interleukin (IL)-6 in the kidney of normotensive Wistar rats and spontaneously hypertensive rats (SHR). DESIGN: In acute studies, the left kidney was exposed and the renal nerves were electrically stimulated to decrease renal blood flow by either 15 or 30% for 1 h. The changes in renal function induced by nerve stimulation were measured and IL-6 production estimated at the end of the experiment. METHOD: Pentobarbitone anaesthetized rats were prepared for the measurement of renal blood flow, glomerular filtration rate and water and sodium excretion. IL-6 production was estimated by the level of IL-6 messenger (m)RNA present in the kidney tissue. RESULTS: At the lower level of nerve stimulation there were reductions in the glomerular filtration rate of 12 and 24% in Wistar and SHR, respectively, and a decrease in sodium excretion of approximately 30% in both rat strains. At higher rates of stimulation these haemodynamic and tubular responses were proportionately larger. The mRNA for IL-6 and beta-actin were measured by densitometric analysis of Northern blot gels following hybridization. Renal IL-6 mRNA levels in the Wistar rat demonstrated that the gene was actively expressed and was increased some threefold by renal nerve stimulation. By contrast, IL-6 mRNA was extremely low in SHR compared with that found in the kidneys of Wistar rats and did not appear to be changed by renal nerve stimulation. CONCLUSIONS: These findings suggest that the renal sympathetic nerves are an important regulatory mechanism for IL-6 production under normal conditions. However, in the SHR, production of IL-6 in the kidney appears to be suppressed.

Animals↗

Genetic study on HLA class II and class III region in the disease associated with IgA nephropathy.

Increased frequency of C4 gene deletions in IgA nephropathy and Henoch-Schönlein purpura nephritis. To determine the frequency of complement 4 (C4) deficiency among the patients with IgA nephropathy (IgAN) and Henoch-Schönlein purpura nephritis (HSPN), C4 and factor B protein allotypes and the DNA restriction fragment length polymorphism (RFLP) of C4, steroid 21-hydroxylase (21OHase), HLA DQ beta and DR beta chain genes were studied. Genomic DNA from 32 patients with IgAN, 24 patients with HSPN and 143 controls was digested with restriction enzyme TaqI or BamHI and subjected to Southern analysis. The frequency of C4 gene deletions was significantly increased in the patients (16.1 vs. 2.8%, p = 0.002). The serum C4 concentration in patients with C4 gene deletion was significantly lower than in patients without gene deletion (11.4 +/- 2.4 vs. 19.7 +/- 5.2 mg/dl, p = 0.001). DNA-RFLP typing of DQB/BamHI and DRB/TaqI showed increased frequency of 10.26 kb of D-DQw4/8/9 (87.5 vs. 64.5%, p = 0.004) and 5.22 kb of D-DR4 (66.1 vs. 41.7%, p = 0.03) among the patients. Segregation analysis showed that the association of the D-DQw4/8/9 and D-DR4 with the diseases was not responsible for the increased frequency of C4 gene deletion in the patients. The decreased concentration of C4 in sera in C4 gene-deleted patients might be directly involved in the pathogenesis of IgAN and HSPN.

Child↗

Endogenous heterogeneity of relaxin and sequence of the major form in pregnant sow ovaries.

Using an extraction procedure that minimized proteolysis, followed by gel filtration, cation-exchange FPLC, and reverse-phase HPLC, the present study unambiguously showed the presence of multiple isoforms of relaxin in the ovaries of pregnant sows. Four relaxin isoforms were isolated (designated as R-I1, R-I2, R-II1 and R-III1). They had a similar migration pattern on SDS/urea PAGE, and showed no significant difference in biological activity. HPLC separation of the reduced and S-pyridylethylated relaxin variants indicated that R-I1, R-I2 and R-III1 each contained multiple relaxin molecules which showed variability of the B-chain, whereas R-II1 contained mostly a single relaxin molecule with only slight B-chain variability. R-II1 was thus considered likely to be the major form of relaxin stored in the ovary. Sequence analysis revealed that R-II1 contained 22 amino-acid residues in the A-chain and 29 residues in the B-chain, with a total molecular mass of 5814.8 Da. It was thus equivalent to CM-a' relaxin designated by Sherwood and O'Byrne (1974).

Amino Acid Sequence↗

Selective expansion of T cells expressing T-cell receptor variable regions V beta 2 and V beta 8 in Kawasaki disease.

Kawasaki disease (KD) is an acute vasculitis complicated by the development of coronary artery abnormalities. The etiology of KD is unknown. Based on the observation that KD is associated with marked activation of T cells and monocyte/macrophages, we hypothesized that KD may be caused by a superantigen [e.g., a bacterial toxin that stimulates T cells expressing particular T-cell receptor beta chain variable (V beta) gene segments]. Peripheral blood T cells from patients in the acute and convalescent phases of KD and from various control groups were analyzed for T-cell receptor V beta gene expression by using a quantitative PCR technique and cytofluorographic analysis with available anti-V beta monoclonal antibodies. Patients with acute KD demonstrated significantly elevated levels of circulating V beta 2+ and V beta 8.1+ T cells compared to the other control groups. none of the other 20 V beta populations analyzed by quantitative PCR were found to be significantly elevated. Using flow cytometry, we confirmed a significant elevation of T cells reactive with anti-V beta 8.1 and the lack of change in several other V beta subsets--i.e. V beta 5.1, -5.2, -6.7, and -12. During the convalescence phase of KD, there was a reduction in the abnormal levels of V beta 2+ and V beta 8.1+ T cells. These observations suggest that KD may be caused by a superantigen and may provide insight into the nature of the etiologic agent.

Gene Expression↗

Expression of peptidylarginine deiminase in the uterine epithelial cells of mouse is dependent on estrogen.

The effects of the steroid hormones estrogen and progesterone on peptidylarginine deiminase protein-L-arginine iminohydrolase, EC 3.5.3.15) levels in adult ovariectomized mouse uterus were studied. The amount of the enzyme in the uterus was considerably diminished by ovariectomy. When the mice were injected with a variety of estrogenic compounds, 17 beta-estradiol-3-benzoate, which was the most potent stimulator of uterine cell proliferation among the estrogens tested, dramatically elevated the enzyme formation of the uterus in a dose- and time-dependent fashion. Results of immunohistochemistry with the antiserum against mouse peptidylarginine deiminase demonstrated that the induction of the enzyme by the estradiol exclusively occurred at the luminal and glandular epithelia, corresponding with the previous findings in the normal estrous cycle. Furthermore, administration of the estradiol significantly increased the content of mRNA coding for peptidylarginine deiminase in uterus, indicating the evidence of regulation in pretranslation. On the other hand, progesterone alone did not restore the enzyme level of the ovariectomized mouse, but moderated the action of estrogen when given in concert with estrogen. Thus, the expression of peptidylarginine deiminase in luminal and glandular epithelia of mouse uterus is controlled by the amount of the steroid hormones estrogen and progesterone.

Animals↗

Sequence variation in Japanese HLA-DRw8 specificity.

There are four DRw8 haplotypes with different DQ alleles in Japanese: DRw8-DQw6 (w1), DRw8-DQw4, DRw8-DQw8(w3), and DRw8-DQw7 (w3). We previously reported the nucleotide sequence of DRB1 gene of DRw8-DQw6(w1) and it was named DRB1*08032. The nucleotide sequences of the other DRw8 DRB1 alleles and their correspondence to internationally recognized DRw8 subspecificities were still unclear. We have cloned these DRB1 genes and determined the nucleotide sequences. The comparison of the sequences with the published sequences revealed that the differences were occurred at two amino acid positions, and these four haplotypes are classified in two groups: (a) DRw8-DQw6(w1) and DRw8-DQw7(w3), and (b) DRw8-DQw4 and DRw8-DQw8(w3). The DRB1 molecules of DRw8-DQw6(w1) and DRw8-DQw7(w3) have Ser57 and Ile67, and those of DRw8-DQw4 and DRw8-DQw8(w3) have Asp57 and Phe67. The former has the same sequence as that of DRB1*08032, and the latter is same as that of DRB1*0802. The classification corresponds to the serologic subtyping, which divides DRw8 into DR8.1 and DR8.2, reported in the 10th Japan HLA Workshop.

Alleles↗

Analysis of HLA-DQA1 in Japanese patients with type 1 diabetes mellitus, using DNA-PCR-RFLP typing.

DNA-polymerase chain reaction(PCR)-RFLP(restriction fragment length polymorphism) typing of the DQA1 gene was performed on 39 patients with type 1 diabetes and 30 controls. Analysis of the frequency of the subtypes of DQA1 alleles, using the DNA-PCR-RFLP typing technique, showed that the DQA1*0301 subtype was most strongly associated with the disease (97.4% vs 56.7%, R.R. = 19.8, pc less than 0.00005). These results indicated that DQA1*0301 may determine the disease susceptibility in the Japanese. In addition, we analyzed the frequency of the subtypes of DQA1 genes in the ten patients carrying the DRW8-DQW8 haplotype, and found that at least eight of them (80%) were classified as having DQA1*0301. The DRW8-DQW8-DQA1*0301 may be one of the susceptible haplotypes among the Japanese.

Diabetes Mellitus, Type 1↗

A new technique for the precise location of lactate and malate dehydrogenases in goat, boar and water buffalo spermatozoa using gel incubation film.

Gel incubation film, which contained gelatin to prevent the diffusion of enzyme during chemical reaction and phenazine methosulfate to operate as a hydrogen acceptor between NADH and tetrazolium, was used and light microscopy revealed that lactate dehydrogenase was located in the head and tail of the spermatozoa as well as in the midpiece, whereas malate dehydrogenase was confined to the midpiece in spermatozoa of the animals examined. In goat spermatozoa, lactate dehydrogenase was associated mainly with the inner acrosomal membrane in the head, the mitochondrial matrix in the midpiece and with flagellar fibrils in the tail, whereas malate dehydrogenase was present only in the mitochondrial matrix.

Animals↗

Evidence for immunoreactive relaxin in boar seminal vesicles using combined light and electron microscope immunocytochemistry.

Light-microscope immunocytochemistry using the peroxidase-antiperoxidase technique and a polyclonal rabbit antiserum raised against purified porcine relaxin showed that cytoplasmic immunostaining for relaxin could be visualized in the epithelial cells of the seminal vesicle. No relaxin immunoreactivity was seen in the testis, epididymis, ductus deferens, prostate or bulbo-urethral gland. A ten times higher concentration of porcine relaxin antiserum was necessary to achieve immunostaining in the seminal vesicle comparable to that in the corpora lutea of pregnant sows. Ultrastructural examination showed that the epithelial cells of the boar seminal vesicle resembled typical protein-secreting cells with prominent rough endoplasmic reticulum and well-developed Golgi apparatus. The most striking feature of these cells was the accumulation of granules with a limiting membrane, which ranged from 200 to 600 nm in diameter and contained flocculent material of moderate electron density. Electron-microscope immunocytochemistry using the protein A-gold technique and relaxin antiserum demonstrated that the granules were the only intracellular organelles that showed immunoreactivity for relaxin. These results indicate that a relaxin-like substance is present in boar seminal vesicles and that the subcellular site of its localization is the granules, suggesting that the seminal vesicle produces and stores a relaxin-like substance, but that it is present at much lower concentrations than in the corpora lutea of pregnant sows.

Animals↗

Characterization of human thymic lymphocytes forming rosettes with stromal cells.

The interaction of thymic lymphocytes and stromal cells is believed to be important for T cell development in thymus. In this study, thymic rosettes (TR), which are cell-cell complexes of thymic lymphocytes and stromal cells, were isolated from human thymic tissue, and were characterized. Treating human thymus with collagenase in mild condition, human TR were successfully isolated. Subsequently, TR were purified by the 1G sedimentation method. Human TR consisted of a stromal cell in center surrounded by lymphocytes. The stromal cells were positive for CD14, CD11b, and HLA-DR but negative for thymic epithelial cell specific mAb, UH-1, suggesting that they are macrophage/dendritic cells. The lymphocytes which formed TR (TRL) were mainly double positive (CD4+CD8+) and CD1+ cells, and few of them expressed bright CD3, indicating that TRL are in the intermediate maturation stage. TRL expressed activation markers (Ta1 and HLA-DR) in a significantly higher percentage of cells than did unselected thymocytes. Blocking test revealed that CD11a and CD2 are involved in the binding of TRL and the stromal cells as adhesion molecules.

Antigens, Surface↗

Complement 4 gene deletion in patients with IgA nephropathy and Henoch-Schönlein nephritis.

The fourth component of complement (C4), especially B isotype, has been said to be deficient in the IgA nephropathy and Henoch-Schönlein nephritis. However, the association between these diseases and C4 deficiency was questioned recently, and the usual C4 allotyping method is unable to discriminate the C4 deficiency from the C4 duplication. So by combining the DNA restriction fragment length polymorphism with the usual C4 allotyping, we tried to determine whether the deficiency of C4 can be demonstrated in the DNA level. We found that the frequency of C4 gene deletion was increased, although the frequency of null phenotype was not different from the control. From these results we can say that C4 gene deletion is a genetic risk factor in these diseases, at least in the Japanese population.

Child↗

[The significance of C4 locus II deletion in IgA nephropathy and Henoch-Schonlein nephritis and it's correlation with other HLA genes].

IgA nephropathy and HSP nephritis share some similar immunological abnormalities, for example, high IgA serum concentration, existence of IgA-IC, alternative pathway activation, monocyte and B-cell activation and the same histological findings of renal biopsy. The genetic factors may play an important role in both diseases. The increased frequency of homozygous null C4 phenotypes was reported in Caucasians. But the regional variation of C4 null alleles were recognized distinctly, and the significance of C4 isotype deficiency remained unclear. We studied the relationship between IgA nephropathy and Class II and Class III HLA antigens in Japanese by not only C4 protein phenotypes but also gene analysis (TaqI, Nla IV and EcoO 109). The frequency of C4 protein isotype deficiency was the same with control groups, but significantly increased C4 gene deletion was observed in both diseases. Neither DR4 nor DQB4/8/9 related to C4 gene deletion, but the total C4 serum concentration was lower in gene deletion groups. We could not detect any deviation between C4A and C4B locus deletion by Nla IV and EcoO 109 analysis. Considering the changing process of C4A to C4B, there is a possibility that the mechanism of deletion process itself causes the elevated sensitivity to the diseases.

Chromosome Deletion↗

Lack of correlation between the amount of eugenol released from zinc oxide-eugenol sealer and cytotoxicity of the sealer.

The purpose of this study was to examine a possible correlation between the eugenol released from a zinc oxide-eugenol sealer (Canals) and the degree of cytotoxicity. The cytotoxicity and eugenol release from root canal filling material containing eugenol was examined for test solutions at several experimental periods. No positive correlation was found between eugenol release and cytotoxicity of the root canal filling material.

Animals↗

Human leukocyte antigens in childhood idiopathic nephrotic syndrome.

An association of human leukocyte antigens (HLA) with idiopathic nephrotic syndrome (INS) in childhood was studied to characterize the immunogenetic background. We determined the class I antigens using the microlymphocytotoxicity test as well as class II antigens (DRB, DQB, DQA) and class III antigen (complement 4) using DNA restriction fragment length polymorphism (RFLP) in 36 children with INS. In the current study, neither the single allele in HLA class I antigen nor the single gene frequency in the class II region was significantly increased, in contrast to the results in Caucasian INS patients in whom a genetic predisposition to the HLA system, especially to HLA B8, DR3, and DR7, has been frequently reported. Also, in our data, the frequency of deletion of complement 4 gene was not different from that of the controls. These data suggest that there is a difference in immunogenetic background between Caucasian and Japanese INS patients as far as HLA is concerned.

Alleles↗

HLA class II (DR, DQ) in Japanese patients with type 1 diabetes mellitus.

DNA restriction fragment length polymorphism (RFLP) typing of HLA-DR and DQ alleles of 60 Japanese type 1 (insulin dependent) diabetic patients and 115 controls was performed. RFLP typing of DRB1 showed increased frequency of DR9 and decreased frequencies of DR2 and DRW6 among patients compared to controls. In the RFLP typing of BamHI-digested DNA to DQ beta probe (BamHI-DQB1), the incidence of the 10.26 kb fragment, which represents either DQW4, DQW8 or DQW9, was markedly elevated in the patients, whereas the incidence of DQW6 was reduced. The predicted DR-DQ haplotype study revealed that DR4-DQW4 or DQW8, DRW8-DQW4 or DQW8 and DR9-DQW9 may contribute to susceptibility to type 1 diabetes. When serological typing of the 13 DRW8 patients was performed, all the 11 DRW8 patients carrying DQW4 or DQW8 (BamHI-10.26 kb) were positive for DQW3. These results indicated that the HLA-DQ locus may play an important role in the development of type 1 diabetes in the Japanese as well as other ethnic groups and that the DRW8-DQW8 haplotype may predispose to the disease in Japan.

Alleles↗