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Biomedical subjects

T Hosoya

Publications and source records attributed to T Hosoya.

At least 199 records · Page 11Linked to original sources
PubMed1993

Individual difference in toxic diffuse goiters assessed by heme-based specific activity and Km value.

Thyroid peroxidase (TPO) was purified from each thyroid of 10 patients (experiment 1) and 4 patients (experiment 2) with toxic diffuse goiter by a simplified method with monoclonal anti-TPO antibody-assisted immunoaffinity column chromatography. The final preparations were used to measure the heme concentration based on the cyanide difference spectrum, and to determine the Km and kcat values from double reciprocal plots in the assay employing guaiacol and iodide as the second substrates. The heme-based specific activities of TPO purified from thyroids in experiment 1 were higher than those in experiment 2, which were probably impaired by freezing-thawing, and those of porcine TPO previously reported. There were some differences in the kinetic properties between experiment 1 and experiment 2, but the individual differences within each group were relatively small, the values for CV (= SD/mean) being 0.16-0.48.

Adolescent↗
PubMed1993

Comparison of the IgG subclass distribution of anti-thyroid peroxidase antibodies in healthy subjects with that in patients with chronic thyroiditis.

The IgG subclass distribution of anti-thyroid peroxidase (TPO) antibodies in patients with chronic thyroiditis and in healthy subjects has been investigated. Anti-TPO antibodies in sera of patients with chronic thyroiditis were predominantly associated with IgG1, with a lesser contribution by IgG4 and IgG3. In contrast, anti-TPO antibodies of healthy subjects were exclusively associated with IgG4. Since structural differences in IgG subclasses reflect differences in their biological roles, these findings suggest that the role of anti-TPO antibodies in patients may differ from that in healthy subjects.

Adolescent↗
PubMed1993

Immunohistochemical studies on thyroid peroxidase and thyroglobulin in 13 human thyroid tumors and 7 Graves' goiters.

Thyroid peroxidase (TPO) in 4 benign tumors, 9 malignant tumors and 7 Graves' goiters was examined both by biochemical methods (guaiacol and iodide oxidation assays) and histochemical methods (indirect immunofluorescence methods with polyclonal anti-TPO antibodies). The protein-based specific activity of TPO of Graves' goiters was comparable to or higher than that of normal thyroid tissues, while that of benign and malignant tumors were comparatively lower and variable. TPO was stained with the polyclonal anti-TPO antibodies in the cytoplasm of all benign adenomas, Graves' goiters and follicular carcinomas, but not of papillary carcinoma and metastatic cells. TPO staining markedly appeared in apical areas of Graves' goiters but was scarcely detected in the areas of other disordered thyroids. Polyclonal anti-thyroglobulin antibodies detected thyroglobulin in the follicular lumen of these diseased thyroids except in metastatic carcinoma cells.

Adenocarcinoma, Follicular↗
PubMed1993

Adenophostins A and B: potent agonists of inositol-1,4,5-trisphosphate receptor produced by Penicillium brevicompactum. Taxonomy, fermentation, isolation, physico-chemical and biological properties.

New inositol-1,4,5-trisphosphate (InsP3) agonists, adenophostins A(1) and B(2), were isolated from the culture broth of Penicillium brevicompactum SANK 11991 and SANK 12177. Its structures were related to adenine nucleotides. The agonistic activity of adenophostins A or B for binding to the InsP3 receptor was higher than InsP3 itself.

Adenine↗
PubMed1993

Aquastatin A, an inhibitor of mammalian adenosine triphosphatases from Fusarium aquaeductuum. Taxonomy, fermentation, isolation, structure determination and biological properties.

A new inhibitor of mammalian adenosine triphosphatases, designated aquastatin A, has been isolated from a fungus identified as Fusarium aquaeductuum. The structure of this compound has been determined by MS and NMR analyses. It inhibits Na+/K(+)-ATPase with an IC50 value of 7.1 microM, and H+/K(+)-ATPase with an apparent IC50 value of 6.2 microM.

Adenosine Triphosphatases↗
PubMed1993

A study of uric acid metabolism and gouty arthritis in patients with polycystic kidney.

It has been found that polycystic kidney (ADPKD) is often associated with gout. On the other hand, there are reports describing that the hyperuricemia (HU) seen in ADPKD corresponds to a reduction in renal function. We investigated the uric acid metabolism in 44 patients with ADPKD (age, 50 +/- 12.8 years; CCR, 50.5 +/- 41.1 ml/min) at our hospital. From among these 44 patients, 14 with a CCR of 80 ml/min were selected. Their data for uric acid metabolism were compared against those from the previous year's studies on various disease types (114 normal subjects, 70 with membranous nephropathy, 175 with IgA nephritis, 122 with gout, 137 with asymptomatic hyperuricemia, and 42 with diabetes mellitus). Among the 44 patients with ADPKD, the serum uric acid (SUA) was 7.7 +/- 1.9 mg/dl and HU affected 28 (63.6%). The incidence of gouty arthritis was also high (6 patients, 13.6%), revealing a positive correlation between SUA and CCR. Compared with membranous nephropathy and IgA nephritis, ADPKD exhibited an accentuated increase in SUA associated with a reduction in CCR. It is believed that this represents a factor for a high incidence of complications of hyperuricemia and gouty arthritis in ADPKD in contrast to other diseases. However, no increase in the production of uric acid was noted in ADPKD.

Adult↗
PubMed1992

[Hemodynamics in the territory of balloon occluded internal iliac artery--problems of balloon occluded arterial infusion therapy for urinary bladder cancer].

Balloon occluded arterial infusion therapy (BOAI) with anticancer drugs has been performed widely for urinary bladder cancer. It is expected that a dense anticancer drug would perfuse the territory of the vesical arteries under occlusion of the bilateral internal iliac arteries. In balloon occluded internal iliac arteriography, however, contrast media are gradually washed out in spite of complete occlusion of the bilateral internal iliac arteries. This washout process takes place via collateral flow to the acute occlusion and varies according to the position of occlusion and arterial variations in branching. We wondered whether anticancer drug administered by BOAI would perfuse the territory of the vesical arteries as expected. We analyzed the washout process of balloon occluded internal iliac arteriography in 41 patients with urinary bladder cancer in whom preoperative BOAI had been performed. We estimated the hemodynamics and perfusion of the anticancer drug to the urinary bladder on the basis of analysis of balloon occluded internal iliac arteriography in each case. Perfusion scintigraphy and histological examination of surgical specimens of urinary bladder cancer (21 cases) confirmed the validity of our estimates. In some cases it was presumed that the anticancer drug did not reach the territory of the vesical arteries.

Adult↗
PubMed1992

Molecular cloning of a Drosophila diacylglycerol kinase gene that is expressed in the nervous system and muscle.

We have isolated a Drosophila melanogaster diacylglycerol kinase (DGK, EC 2.7.1.107) homologue by using a porcine DGK cDNA probe and we have characterized its structure and expression. The DGK cDNA has a single open reading frame that encodes 791 amino acids. The Drosophila and porcine DGKs share a similar carboxyl-terminal region, a putative catalytic domain, which is divided into two separate domains in Drosophila. The DGK gene was mapped to the cytogenetic position 43F1, and its DGK mRNA is abundant both in embryo and in adult fly. By in situ hybridization to sections of adult flies, we demonstrated that the mRNA is present predominantly in the nervous system and muscles, including compound eyes, brain cortex, fibrillar muscle, and tubular muscle. In a 10- to 11-hr embryo, the DGK gene is expressed abundantly in a limited number of cells in the procephalic region and in the ventral nerve cord. The pattern of temporal and spatial expression suggests that the DGK protein has an important function in the adult nervous system and muscle and during the development of the embryonic nervous system.

Amino Acid Sequence↗
PubMed1992

[Non-tumor enhancement at the surgical margin on CT after the removal of brain tumors].

Marginal enhancement is occasionally seen at the surgical margin on CT after the total removal of brain tumors. This enhancement disappears in due time, and therefore we call it non-tumor enhancement. It is often difficult, however, to differentiate non-tumor enhancement from tumor recurrence. In this study, we attempted to determine the characteristics of non-tumor enhancement. The subjects of the study consisted of 15 patients with astrocytoma and one with metastatic tumor in whom sequential CT scans had been performed after total removal of the tumor. Based on the observation of these sequential CT scans, the characteristics of non-tumor enhancement were presumed to be as follows: 1) In four cases, enhancement at the surgical margin persisted more than four months after surgery and then disappeared. Therefore, these cases were considered non-tumor enhancement. Prolonged duration of enhancement such as that in these cases is not necessarily due to recurrence. 2) Marginal enhancement within 3 mm in thickness and with a well-demarcated border like that of a falx is likely to be non-tumor enhancement.

Adolescent↗
PubMed1992

Dilatation of the temporal horn in subarachnoid haemorrhage.

CT studies of 50 patients with spontaneous subarachnoid haemorrhage (SAH) and 100 randomly selected patients were reviewed with regard to the size of the frontal and temporal horns of the lateral ventricles. The temporal horn was classified into four grades, based on the size of its posterior portion at the level of the midbrain. The horn was clearly visible in 66% of patients with SAH, but in only 2% of controls. In the SAH group, the temporal horn tended to dilate sooner than the frontal horn after haemorrhage and could be seen clearly in a larger proportion of patients. Thus, assessment of the size of the temporal horn appears to be a simple and sensitive method for assessing ventricular dilatation. In addition, dilatation of the temporal horn may prove to be an important indirect sign suggesting SAH in patients in whom no high density clot is seen on CT.

Adult↗
PubMed1992

Effects of inorganic iodide, epidermal growth factor and phorbol ester on hormone synthesis by porcine thyroid follicles cultured in suspension.

Porcine thyroid follicles cultured in suspension for 96 h synthesized and secreted thyroid hormones in the presence of thyrotropin (TSH). The secretion of newly synthesized hormones was assessed by determining the contents of thyroxine (T4) and triiodothyronine (T3) in the media and by paperchromatographic analysis of 125I-labelled hormones in the media where the follicles were cultured in the presence and absence of inhibitors of hormone synthesis. The hormone synthesis and secretion was modified by exogenously added NaI (0.1-100 microM). The maximal response was obtained at 1 microM. Thyroid peroxidase (TPO) activity in the cultured follicles with TSH for 96 h was dose-dependently inhibited by NaI. One hundred microM of NaI completely inhibited TSH-induced TPO activity. Moreover, both epidermal growth factor (EGF: 10(-9) and 10(-8) M) and phorbol 12-myristate 13-acetate (PMA: 10(-8) and 10(-7) M) inhibited de novo hormone synthesis. An induction of TPO activity by TSH was also inhibited by either agent. These data provide direct evidences that thyroid hormone synthesis is regulated by NaI as well as TSH at least in part via regulation of TPO activity and also that both EGF and PMA are inhibitory on thyroid hormone formation.

Animals↗
PubMed1992

Effect of dexamethasone on nucleolar casein kinase II activity and phosphorylation of nucleolin in lymphosarcoma P1798 cells.

Ribosomal RNA (rRNA) synthesis in murine P1798 lymphosarcoma cells is reversibly inhibited by glucocorticoids. The effects of dexamethasone upon nucleolin phosphorylation and upon the amount and activity of casein kinase II have been examined. P1798 cells were exposed to 0.1 microM dexamethasone for 36 h. Cells were labeled in vivo with [32P]orthophosphate followed by immunoprecipitation with anti-nucleolin antibody. Nucleolin phosphorylation was reduced by 60% in dexamethasone-treated cells. Nucleoli were isolated and labeled with [gamma-32P]ATP in vitro. Nucleolin protein was reduced to 40% of control in nuclei from dexamethasone-treated cells. Nucleolin phosphorylation was reduced to 20% of control. Nucleolar casein kinase II activity and protein were also reduced (30-55% and 35-50% of control, respectively) by treatment with dexamethasone. Cycloheximide (10 micrograms/ml for 3 h) reduced the amount and activity of casein kinase II, but did not cause a decrease in nucleolin protein. These observations are discussed relative to the hypothesis that glucocorticoids regulate the amount or activity of proteins of short biological half-life that are involved in the regulation of rRNA synthesis.

Animals↗
PubMed1992

Peroxidase and coupling activities of thyroid peroxidase in benign and malignant thyroid tumor tissues.

The coupling activity of thyroid peroxidase (TPO) in thyroid glands from patients with benign adenoma, papillary carcinoma, and diffuse goiter (Graves' disease) was measured for the first time, in addition to the peroxidase activity of these tissues. The peroxidase activity of TPO in the mitochondria-microsomes fraction was measured with guaiacol or iodide as the second substrate. In the case of papillary carcinoma, the mean protein-based specific activity obtained by the guaiacol assay was about 1/7 of that of diffuse goiter. The iodide oxidation activity of carcinoma was very low, about 1/25 [corrected] of that in diffuse goiter and 1/70 of that in adenoma. The peroxidase activity in adenoma was almost similar in the guaiacol oxidation assay and approximately one half in the iodide oxidation assay as compared with that in diffuse goiter. There was a close correlation between the guaiacol and iodide oxidation assays in individual patients with adenoma and diffuse goiter, but not in patients with papillary carcinoma. The coupling activity of TPO was measured with thyroglobulin purified from pooled toxic diffuse goiters and chemically iodinated to contain little additional T3 and T4. The specific coupling activity of TPO in mitochondria-microsomes from carcinoma was significantly lower (about 1/5) than that of diffuse goiter, and the activity in adenoma was not significantly different (about 1/2) from that of diffuse goiter. The data of coupling activities has a close correlation with that of peroxidase activities in individual patients with adenoma but not in patients with carcinoma. Based on these findings, the qualitative abnormality of TPO and its relation to the cold 123I scintigram in thyroid tumors are discussed.

Adenoma↗
PubMed1991

[Enzymatic iodination of thyroglobulins obtained from patients with thyroid disease].

Iodination of the isolated thyroglobulin (Tg) by peroxidase was compared with various Tg preparations obtained from patients with thyroid diseases. For the purpose, the iodination process was observed in the incubation medium containing Tg, iodide, H2O2-generating system, and thyroid peroxidase (TPO) or lactoperoxidase (LPO). During the incubation, iodination of Tg preparations increased gradually and reached a plateau after 90 min., and 5 min. incubation with 3mIU or 14mIU of TPO, respectively. The degree of iodination level at the plateau region was different in each Tg preparation, depending on the iodine content of the original starting (native) preparation before incubation. The iodination level of cancer Tg with a very low iodine content (less than 0.1%) was low compared with the normal Tg level (obtained from normal thyroid tissue which contained about 0.4% iodine). The above findings suggest the possible existence of some structural differences of Tg in terms of the susceptibility to the iodination between the preparations of normal and diseased Tgs. As far as the immunological aspect concerned, there was no significant difference in the affinity (avidity) of Tg with polyclonal anti-Tg antibody between the native Tg and the enzymatically iodinated one. These results suggest that the changes of iodine and thyroid hormone contents of Tg by in vitro iodination, has no significant effect on the immunological property of Tg molecule.

Antigen-Antibody Reactions↗