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S Hosogaya

Publications and source records attributed to S Hosogaya.

At least 19 recordsLinked to original sources
PubMed2001

Involvement of Hic-5 in platelet activation: integrin alphaIIbbeta3-dependent tyrosine phosphorylation and association with proline-rich tyrosine kinase 2.

Hic-5 and paxillin, members of the LIM protein family, have been shown to be localized in focal adhesion and to have a role in integrin-mediated signalling. In the present study we examined the involvement of Hic-5 in human platelet activation: platelets express Hic-5 but not paxillin, whereas human umbilical-vein vascular endothelial cells and MEG-01 cells express mainly paxillin. When platelets were stimulated with thrombin, collagen or the stable thromboxane A(2) analogue U46619, Hic-5 was markedly tyrosine-phosphorylated, in a manner dependent on integrin alphaIIbbeta3-mediated aggregation. In addition, direct activation of protein kinase C with PMA resulted in tyrosine phosphorylation of Hic-5 only when platelets were fully aggregated with the exogenous addition of fibrinogen. Furthermore, PMA-induced Hic-5 tyrosine phosphorylation was also observed when platelets adhered to immobilized fibrinogen. In studies on immunoprecipitation and immunodepletion, Hic-5 seemed to associate with proline-rich tyrosine kinase 2 (Pyk2) but only marginally with focal adhesion kinase. When platelets were stimulated with thrombin, both Hic-5 and Pyk2 translocated to the cytoskeleton from the cytosol and membrane fractions in a manner dependent on alphaIIbbeta3-mediated aggregation. Finally, on stimulation with PMA, Hic-5, as well as Pyk2, translocated to the cell periphery, where a meshwork of actin filaments assembled after adhesion to immobilized fibrinogen. Our results suggest that Hic-5 might be important in platelet aggregation and adhesion, in a manner dependent on alphaIIbbeta3-mediated outside-in signalling, through association with Pyk2.

Blood Platelets↗
PubMed2000

Antibody studies of factor VIII inhibitor in a case with Waldenström's macroglobulinemia.

We report a case of Waldenström's macroglobulinemia with prominent bleeding tendency; laboratory investigation revealed an elevated activated partial thromboplastin time. Further laboratory evaluation showed circulating factor VIII anticoagulant, deemed polyclonal IgG, with a titer of 700 Bethesda Units/ml. The factor VIII inactivation kinetics of the patient plasma were identical to those of a type II inhibitor, and the inhibitor was found to recognize the A2 domain of the factor VIII heavy chain. Apparently, paraprotein is not always the cause of reduced activity of coagulation factors in neoplastic dysproteinemias.

Aged↗
PubMed1999

[Biological inter- and intra-individual variations of serum immunochemical constituents and their allowable limits of analytical error].

The biological inter- and intra-individual variations of serum immunochemical constituents were estimated by the analysis of variance. Twelve samples taken at weekly intervals were analyzed for 22 healthy individuals. As for immunoglobulin (Ig) G, IgA, IgM, IgE, C-reactive protein, anti-streptolysin O, alpha-fetoprotein, complement component 3 and 4, and ferritin, the intra-individual variations (with coefficient of variations (CVs) ranging from 4.8% to 51.7%) were smaller than the inter-individual variations (with CVs ranging from 14.6% to 107.6%). The values for carcinoembryonic antigen (with CVs of inter- and intra-individual variation being 31.6% and 39.6%, respectively) and beta 2-microglobulin (with CVs of inter- and intra-individual variation being 14.4% and 13.1%, respectively) were similar. The biological variations of serum immunochemical constituents, examined in this study, were larger than those of serum chemical constituents. Based on our data, we propose allowable limits of analytical error, which is less than one-half of the average intra-individual variation for evaluation of imprecision and is less than one-quarter of the inter- plus intra-individual variation for evaluation of inaccuracy.

Analysis of Variance↗
PubMed1998

Acquisition versus loss of Helicobacter pylori infection in Japan: results from an 8-year birth cohort study.

Studies of the pattern of change in the epidemiology of Helicobacter pylori infection are scarce. A longitudinal cohort study consisted of 644 children and adults, and two independent cross-sectional surveys were conducted in rural Japan between 1986 and 1994. The anti-H. pylori IgG seroconversion rates were 1.1% and 1% per year for children and adults, respectively. The seroreversion rate per year was 1.8% for children and 1.5% for adults. The cohort study was confirmed by the two cross-sectional studies. H. pylori prevalence fell in all age groups in both children (odds ratio [OR] = 0.5, 95% confidence interval [CI] = 0.2-1.0, P = .05) and adults (OR = 0.4, 95% CI = 0.3-0.6, P = .001). The rate of loss of H. pylori infection was greater than the acquisition. Data regarding acquisition and loss of H. pylori infection are critical to understanding the epidemiology of the infection and to developing treatment and vaccination strategies.

Adolescent↗
PubMed1998

[Immunohistochemical study on keratin no. 8, 18 and 19 expression of carcinoid tumors].

The purpose of this study is to evaluate keratin expression in neuroendocrine cells and carcinoid tumor of the gastrointestinal tract and lung. Neuroendocrine cells in the lung and the gastrointestinal tract reacted with low-molecular keratin strongly, but not with high-molecular keratin. The low-molecular keratin expression of carcinoid tumor in the lung and the gastrointestinal tract, which varied in degree, were identical to that of neuroendocrine cells. Keratin 8 and 18 were found abundantly in neuroendocrine tumor and carcinoid tumor of the gastrointestinal tract, and in a lesser amount in carcinoid tumor of the lung, whereas keratin 19 was found in all cases with variable amounts. Based on these results, the combination of antibodies for several types of keratin is useful for examining keratin expression as a marker of epithelium in carcinoid tumor.

Adult↗
PubMed1996

CETP is a determinant of serum LDL-cholesterol but not HDL-cholesterol in healthy Japanese.

Cholesteryl ester transfer protein (CETP) is one of the factors that regulate plasma levels of HDL-cholesterol. To identify the factors that may regulate CETP activity, and to determine to what extent CETP is correlated with physiologic concentrations of lipoprotein, we performed an epidemiologic study in 586 healthy volunteers (317 males and 269 females mean age 52.2 +/- 10.9 years). CETP activity in these subjects was 192.96 +/- 48.73 (mean +/- S.D.) nmol/ml/h and distributed to a wide range (60-450 nmol/ml/h). Using multiple regression analysis, we found significant positive correlations between CETP activity and LDL-cholesterol (P < 0.03), apolipoprotein (apo) E (P < 0.005) and LCAT activity (P < 0.001). CETP activities showed significant negative correlation with apo A-I (P < 0.03). However, CETP activity showed no significant correlation either with HDL cholesterol or with apo B. One-way layout analysis of variance showed that alcohol drinking and cigarette smoking significantly reduced CETP activity, but there was no significant association between CETP activity and body mass index. Although CETP activities were significantly higher in females than in males (P < 0.001), multiple regression analysis showed no correlation between CETP activity and age in either the males or the females. Our results suggest that CETP activity regulates the concentration of apo A-I and LDL-cholesterol, and that such activity may be influenced by gender, alcohol consumption and cigarette smoking.

Adult↗
PubMed1995

[Enzyme amplification in enzyme immunoassay].

In enzyme immunoassay, the catalytic activity is determined by photometric assay of the substrate, and in a broad sense, it also includes fluorometric and chemiluminescent assays. Since enzyme immunoassay excells in specificity and detectability, it is widely applied to clinical tests which analyze various specimens. Here, we describe some of enzyme amplification methods including cyclic reactions, avidin-biotin reactions and enhanced chemiluminescent enzyme immunoassays. These methods have resulted in highly sensitive immunoassays, the level of which ranges from a attomole (1 x 10(-18) mol) to a zeptomole (1 x 10(-21) mol).

Avidin↗
PubMed1995

[Clinical and etiological studies of IgG antibodies to Helicobacter pylori detected by enzyme-linked immunosorbent assay].

Recently, Helicobacter pylori (H. pylori) has been reported that it is involved in the pathogenesis of duodenal ulcer and might be a risk factor for gastric cancer. To diagnose H. pylori infection, detection of serum antibody is much less stressful and more cost effective than gastric biopsy. Using a serological method, We have reported that the prevalence of serum anti-H. pylori IgG was elevated with age among healthy subjects and over 80% among elder people. Thus, it would be essential to investigate the specificity of the ELISA system (PirikaplateG Helicobacter) for the detection of serum anti-H. pylori IgG. Sera from healthy controls (n = 653) and patients (n = 116) with gastritis, gastric ulcer, and/or duodenal ulcer were studied for anti-H. pylori IgG. Cross reactivity of the anti-H. pylori IgG with closely related bacteria was less than 10% (with C. jejuni: 7.4%, C. laridis: 0.2%, E. coli: -2.4%) in the ELISA system. Anti-H. pylori IgG from both normal controls and the patients were equally neutralized with the extract of H. pylori. Of note was that the prevalence of anti-H. pylori IgG among patients was significantly higher than that among normal controls. Referring to the diagnoses by gastric biopsy, the sensitivity and specificity of this ELISA were 88.2% and 74.2%, respectively. We also demonstrated the clinical usefulness of this ELISA by receiver operating characteristic curve (ROC). Interestingly, several healthy subjects positive for serum anti-H. pylori IgG were voluntarily subjected to gastric biopsy, and proved positive for H. pylori infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Immunohistochemical study on keratin expression of uterine reserve cells].

An immunohistochemical expression in the reserve cells of the uterine cervix using monoclonal antibodies of cytokeratin which detected the different subtypes of keratin was studied. Although the reserve cells were positive for all the four cytokeratin antibodies (CAM5.2, M-20, M-888, M-630), different immunoreactivity was found as follows: CAM5.2 reacted uniformly and intensely in the cervical glands, but weak in the reserve cells. M-20 reacted similar to that of CAM5.2 in the cervical glands, but was weaker stained in the reserve cells than with CAM5.2. M-888 reacted uniformly and intensely in both the cervical glands and reserve cells. M-630 reacted only in the reserve cells, but seldom in the cervical glands. Hence, CAM5.2 and M-20, which detected No.8 and No.18 of antiserum for low-molecular weight cytokeratin, reacted more weakly in the reserve cells than in the cervical glands, and M-630, which detected No.5 and No.14 of antiserum for high-molecular weight cytokeratin, reacted uniformly and intensely in the reserve cells. That results suggested the reserve cells revealed the expression as the stratified squamous epithelium. As for cell proliferation on the cervical glands and reserve cells, the positive nuclear staining for proliferating cell nuclear antigen (PCNA) was found in both of them, especially in the cervical glands just above the reserve cells. Therefore, the reserve cells had characteristics of squamous cell epithelium and developed to metaplastic cells.

Antibodies, Monoclonal↗
PubMed1975

Arginine gene cluster of Serratia marcescens.

Biochemical and genetic studies on the arginine-requiring auxotrophs derived from a Serratia marcescens strain were carried out. The arg mutants were classified into seven biochemical groups based on their growth response to five precursors of arginine biosynthesis and enzyme deficiency. Reciprocal transduction tests among these arg mutants divided them into three linkage groups, and the fine mapping in each of the groups by two- or three-point crosses revealed the following arrangement of loci. (1) arg44-thy11-lys1; (2) met1-glt2-argE-(arg19-arg51)-arg120-argG-argH; (3) arg33-pyr4. Five of the seven biochemically distinct arg mutants belonged to the second linkage group, and they constituted an agr-gene cluster. A characteristic feature of the arg-gene cluster of S. marcescens is that it involves argG, which was previously reported only in the Proteus group of Enterobacteriaceae.

Arginine↗