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S Ohtaki

Publications and source records attributed to S Ohtaki.

At least 19 recordsLinked to original sources
PubMed1992

A new tumor-associated antigen useful for serodiagnosis of hepatocellular carcinoma, defined by monoclonal antibody KM-2.

After immunization of mice with the human hepatocellular carcinoma (HCC) cell line PLC/PRF/5, we produced monoclonal antibody KM-2, which allowed us to characterize a new HCC-associated antigen (KM-2 antigen) and to develop a sandwich-type radioimmunoassay. The KM-2 antigen was strongly expressed on the cell surface of HCC cell lines. Immunofluorescence staining of frozen sections of different tissues and tumors confirmed its specific expression on the cell surface of a group of HCC. The antigen was also detected in the bile canaliculi of normal liver. Its biochemical characterization revealed a high molecular weight (M(r) approximately 900,000) glycoprotein with an N-linked carbohydrate chain close to the peptide epitope recognized by the KM-2 monoclonal antibody. By the radioimmunoassay for the KM-2 antigen, the antigen was detected in sera of 72 (47%) of 154 patients with HCC and 3 (3%) of 102 patients with liver cirrhosis; it was not detected in 96 patients with chronic hepatitis or in 100 healthy control individuals. The positive rate of KM-2 antigen (72 of 154, 47%) was significantly (P less than 0.01) higher than that (51 of 154, 33%) of alpha-fetoprotein (AFP) when the cut-off level of AFP was taken as the widely accepted 400 ng/ml. No significant correlation was recognized between serum levels of the KM-2 antigen and AFP (r = 0.15; P greater than 0.05). In addition, among 103 patients with HCC whose AFP levels were less than 400 ng/ml, 31 (30%) were positive for the KM-2 antigen. Determination of the serum KM-2 antigen would be useful for the serodiagnosis of patients with HCC, particularly in cases with normal or low AFP levels.

Antibodies, Monoclonal↗
PubMed1992

Identification of thyroiditogenic epitope on porcine thyroid peroxidase for C57BL/6 mice.

C57BL/6 mice show thyroid lesions when immunized with porcine thyroid peroxidase (pTPO) emulsified in CFA. We attempted to clarify a thyroiditogenic epitope on pTPO. Thyroid peroxidase treated with cyanogen bromide was fractionated by reverse phase chromatography, and six fractions (A to F) were obtained. Two of these fractions (D and E) stimulated lymph node cells (LNC) primed with pTPO in vitro and induced thyroiditis in vivo. Tricine-SDS-PAGE and rechromatography showed that fraction D consisted solely of a fragment of Mr 9500 Da and that fraction E contained mainly fragments of Mr of 5400 and 9500 Da. The fragment of fraction D was rechromatographed and 20 NH2-terminal amino acids were analyzed. This segment was found to correspond to residue 726-745 of pTPO deduced from cDNA at a probability of 80%. Four peptides ranging from residue 746-827 were first synthesized and tested for their thyroiditogenicity. Only Pep-2 (29 amino acids) could stimulate LNC primed with pTPO and induce thyroiditis. Pep-2 was divided into two smaller peptides (Pep-2-1 and -2-2) and their thyroiditogenicity was tested again. Pep-2-1 corresponding to residue 774-788, GPA-QITCTPRGWDSP, had thyroiditogenicity as well as the ability to stimulate LNC. It was thought that this segment was at least one of the thyroiditogenic epitopes on porcine thyroid peroxidase for C57BL/6 mice.

Amino Acid Sequence↗
PubMed1992

Fistuloscopy for the management of postoperative intra-abdominal abscesses.

A new technique of fistuloscopy for evaluation and treatment of postoperative intra-abdominal abscesses is described which was used in 8 patients in whom drainage of abscesses following surgery was insufficient. A cholangiofiberscope was introduced into the fistula canal produced by the postoperative drainage. Fistuloscopy was combined with fistulography in all cases to delineate the extent of the inflammatory process. The guidewire was then placed under visual control through the endoscope followed by re-introduction of the drainage tube until a position most effective for pus drainage was achieved. Following this procedure, fever resolved in all 8 patients. Fistuloscopy is recommended to achieve sufficient drainage of intra-abdominal abscesses in those cases where percutaneous ultrasound- or CT-guided drainage fails to lead to significant clinical improvement.

Abscess↗
PubMed1992

Immunohistochemical localization of dipeptidyl aminopeptidase IV in thyroid papillary carcinoma.

The localization of dipeptidyl aminopeptidase IV expressed aberrantly in thyroid carcinoma was studied by immunoelectron microscopy using a monoclonal antibody to the enzyme with special reference to enzyme-histochemical staining of the enzyme. Five thyroid papillary carcinomas were investigated including two lymph-node metastases. All cases showed the dense immunoreaction product on the apical membrane and only traces of the product on lateral membranes, endoplasmic reticulum and nuclear membranes. In one case only, the dense product was observed on basal tubular structures. Analysis, using immunogold labelling on pre-embedded cryosections, revealed that dipeptidyl aminopeptidase IV was localized on the luminal surface of cancer cells. Two different distribution patterns of dipeptidyl aminopeptidase IV activity staining, diffuse and apical patterns, reported previously were thought to be due to different amounts of dipeptidyl aminopeptidase IV in the cytoplasm of cancer cells. This enzyme-histochemical staining method is useful for pathological diagnosis of thyroid tumours and can be applied to clinical materials. The enzyme localization is revealed by the staining pattern.

Adolescent↗
PubMed1991

Expression of dipeptidyl aminopeptidase IV activity in thyroid carcinoma.

Dipeptidyl aminopeptidase IV activity staining was performed in various thyroid tissues to evaluate this enzyme activity as a thyroid tumor marker. A total of 195 thyroid tissues were tested for their enzyme activity expression. All papillary and follicular carcinomas, 40 cases and 3 cases, respectively, showed enzyme activity, although two other carcinomas, one medullary and one anaplastic, were not stained. Follicular adenoma expressed enzyme activity in 4 of 26 cases. Fifty-two cases with adenomatous goiter, 54 with Graves' disease and 13 with chronic thyroiditis were judged to be negative. Five normal thyroids expressed no activity except for occasional positive staining of capillary endothelia. These data suggest that dipeptidyl aminopeptidase IV activity staining is very useful for pathological diagnosis of thyroid tumors.

Dipeptidyl Peptidase 4↗
PubMed1991

Mechanism of H2O2 production in porcine thyroid cells: evidence for intermediary formation of superoxide anion by NADPH-dependent H2O2-generating machinery.

Hydrogen peroxide (H2O2), which is required for thyroid hormone synthesis, has been believed to be produced at the apical cell surface of thyroid follicular cells. However, we recently found that plasma membrane from porcine thyroid exclusively generated superoxide anion (O2-) by employing a novel method for simultaneous determination of H2O2 and O2- with diacetyldeuterioheme-substituted horseradish peroxidase (diacetyl-HRP) as the trapping reagent [Nakamura, Y., Ohtaki, S., Makino, R., Tanaka, T., & Ishimura, Y. (1989) J. Biol. Chem. 264, 4759-4761]. The present study describes the mechanism of H2O2 production as analyzed by this new method. Incubation of cultured porcine follicular cells with ionomycin, a Ca-ionophore, caused an increase in oxygen uptake of about 80%. During enhanced respiration, the cells released H2O2 in an amount equivalent to the amount of oxygen consumed as judged by the formation of compound II of diacetyl-HRP, and H2O2 adduct of the peroxidase. No formation of compound III of the peroxidase, an O2- adduct, was detected during burst respiration. Thus, the intact cells exclusively released H2O2 to the outside of the cells. On the other hand, when the cell fragments from follicular cells were incubated with NADPH or NADH in the presence of Ca2+, the production of O2- was observed only during NADPH-dependent burst respiration, supporting our previous results that the plasma membrane exhibited NADPH-dependent O2(-)-generating activity. O2- production by the plasma membrane was further confirmed by analyses of the effects of superoxide dismutase (SOD) and catalase on the reaction. These results suggested that H2O2 is secondarily produced through the dismutation of O2-.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Dipeptidyl aminopeptidase IV staining of cytologic preparations to distinguish benign from malignant thyroid diseases.

Staining for dipeptidyl aminopeptidase IV (DAP IV [EC: 3.4.14.5]) activity was applied to aspiration biopsy specimens or imprint preparations of surgical biopsy specimens from thyroid tumors. Material was obtained from 55 patients with histologically proven thyroid diseases: 9 with papillary carcinoma, 5 with follicular carcinoma, 11 with follicular adenoma, 13 with adenomatous goiter, 8 with Hashimoto's thyroiditis, and 9 with other benign conditions. Most tumor cells, follicular lumina in cell clusters, and intranuclear inclusions were strongly positive for DAP IV in all examples of papillary or follicular carcinoma. In contrast, only a few epithelial cells were labeled for DAP IV in follicular adenoma and adenomatous goiter. Some Hürthle cells in Hashimoto's thyroiditis also were positive for DAP IV. When a DAP IV scoring system based on the percentage of positive cells and staining intensity was used, all benign tissues except one (from a follicular adenoma) were found to have extremely low scores. These results indicate that staining for DAP IV activity is a simple but useful tool to aid in distinguishing benign from malignant thyroid neoplasms.

Adenocarcinoma↗
PubMed1991

[A case of postpartum fever caused by Mycoplasma hominis infection].

A 26-year-old housewife was admitted to our hospital with a history of high fever after previous cesarean delivery. She had premature rupture of the membrane on the 41st week of pregnancy and the amniotic fluid was found to be cloudy on the fourth day after rupture. Therefore, cesarean delivery was performed. On the first day of operation, her body temperature increased up to 38 degrees C in spite of the treatment with Latamoxef (LMOX), 3 g/day. A sample of intrauterine material yielded M. hominis in pure culture. After administration of Minocycline (MINO) with antimycoplasmal activity, the clinical symptoms improved by the 11th day of operation. Sera obtained after the infection showed antibodies to M. hominis in ELISA study. These results suggested that the cause of this postpartum fever was M. hominis infection.

Adult↗
PubMed1991

[Detection of immature granulocytes and atypical and/or abnormal lymphocytes using scatterplots of Coulter STKS].

Scatterplots of the Coulter STKS were studied in order to make better analyses of morphological abnormality of leukocytes. The analytical pattern of a sample failed to completely prevent blood coagulation, especially platelet aggregation, showed the poor separation between lymphocyte and neutrophil populations. On the scatterplot, a small population was occasionally observed in the lower area of normal lymphocyte population with elevation of room temperature, being thought an artificial population. When atypical and/or abnormal lymphocytes increased, the pattern was characterized by the distribution of large lymphoid cells spreading over monocyte population area. The characteristics became clear in proportion to the percentage of large lymphoid cells. To detect immature granulocytes, we introduced a criterion originated in our laboratory. Using the detection criterion, we could obtain the satisfactory results with sensitivity of 85%, specificity of 93%, efficiency of 91% and coefficient correlation (r) of 0.73. It is concluded that the pattern analysis and the detection criterion are useful in the experiments using routine laboratory samples and valuable in clinical implication.

Autoanalysis↗
PubMed1990

Iodothyronine-induced catalatic activity of thyroid peroxidase.

Iodothyronines induced catalatic (H2O2-decomposing) activity of thyroid peroxidase and lactoperoxidase, the effect increasing in the order of thyroxine (T4) greater than triiodothyronine (T3) greater than diiodothyronine (T2). The iodothyronines served as electron donors in the peroxidase reactions, and during the reactions the catalytic intermediate of thyroid peroxidase was confirmed to be Compound II for T4 and Compound I for T3 and T2 and from the Soret absorption spectra obtained by stopped-flow measurements. Rate constants for the reactions between T4 and Compound II, T3 and Compound I, and T2 and Compound I were estimated at 1.9 x 10(5), 1.3 x 10(6), and 7.1 x 10(5) M-1.s-1, respectively. Unlike the case of thyroid peroxidase, the catalytic intermediate of lactoperoxidase observed during the oxidation of iodothyronines was invariably Compound II. From these and other data it was concluded that thyroid peroxidase catalyzed one-electron oxidation of T4 and two-electron oxidations of T2 and T3 while lactoperoxidase catalyzed exclusively one-electron oxidation of the iodothyronines. Iodide was released during the enzymatic oxidation of iodothyronines, irrespective of the mechanism of one-electron and two-electron oxidations. The amount of released iodide increased in the order of T4 greater than T3 greater than T2. The iodothyronines-induced catalatic activity of these peroxidases was ascribable to the release of iodide, but it was also found that the iodide-enhanced catalatic activity was stimulated by iodothyronines. In this case the effect of iodothyronines was greater in the order of T2 greater than T3 greater than T4, which was consistent with the order of iodothyronine activation for the iodinium cation transfer from enzyme to acceptor.

Animals↗
PubMed1990

Experimental murine thyroiditis induced by porcine thyroid peroxidase and its transfer by the antigen-specific T cell line.

Thyroid peroxidase purified from porcine thyroid (pTPO) was found to induce an experimental murine thyroiditis with genetic restriction which was very different from that induced by mouse thyroglobulin (mTg). C57BL/6 and C57BL/10 (both H-2b) were good responders for thyroiditis, whereas A/J (H-2a), BALB/c (H-2d), DBA/2 (H-2d), CBA (H-2k), C3H/He (H-2k), and SJL/J (H-2s) were poor responders. Genetic analyses using congenic or recombinant strains revealed the following results: The H-2-linked gene (probably the I-A subregion) had a weak association with the induction of thyroiditis, and at least one non-H-2-linked gene controlled the development of thyroid lesions; antibody production to pTPO, porcine thyroglobulin (pTg) and mTg did not correlate with the incidence of thyroiditis in any strain. None of the murine thyroid microsome-specific antibodies tested by the indirect immunofluorescent technique was detected. The T cell line specific for pTPO was successfully transferred to produce thyroid lesions in C57BL/6 mice. Thyroiditis appeared 3 days after the transfer of T cell blasts, and a low concentration of anti-pTPO antibodies was detected concurrently. Thyroid lesions remained up to 48 days with almost the same extent of thyroiditis, but anti-pTPO antibodies gradually increased. In the vaccination experiments using either 0.645 C/kg (2500 rad)-irradiated or 0.3% glutaraldehyde-fixed T cell blasts, the induction of thyroid lesions by transfer was strongly suppressed. Glutaraldehyde fixation was more effective than X-irradiation in preventing thyroiditis after the transfer of T cell blasts. Vaccination also suppressed significantly the development of thyroid lesions after pTPO administration.

Animals↗
PubMed1990

Transcellular iodide transport and iodination on the apical plasma membrane by monolayer porcine thyroid cells cultured on collagen-coated filters.

Isolated porcine thyroid follicular cells were cultured on a collagen-coated Millipore filter to form a monolayer. The monolayer could translocate 125I added in the medium beneath the filter (basal medium) into the medium above the monolayer (apical medium) and form an iodide concentration gradient of several-fold. Transcellular iodide pump activity was observed when the cells were cultured with TSH in the basal medium. In the absence of TSH, the translocation of iodide was very slow. The concentration of TSH required to activate the iodide pump was 0.1-0.3 mU/ml. Addition of ClO4- to the basal medium inhibited transcellular transport, whilst addition of ClO4- to the apical medium was much less effective. Constituents labelled with 125I in the apical medium were analysed. The amount of protein-bound 125I measured by acid precipitation was 3-8% of the total radioactivity. The residual radioactivity was found to be iodide ion by paper chromatography. Further analysis by sodium dodecylsulphate-polyacrylamide gel electrophoresis revealed that most of the 125I-labelled protein was at the position of bovine serum albumin which had been added to the culture medium. The monolayer culture of cells on collagen-coated filter would be a useful experimental system for analysing thyroid cell functions for which the cell polarity is essential.

Animals↗
PubMed1990

Extracellular ATP-induced production of hydrogen peroxide in porcine thyroid cells.

Hydrogen peroxide (H2O2) is an essential substrate for the peroxidase reaction in thyroid hormone biosynthesis. We demonstrated the production of H2O2 from porcine thyroid cells stimulated with extracellular ATP, using a scopoletin-horseradish peroxidase (HRP) system. Incubation of isolated cells for 1 day in the presence of 10% (v/v) newborn calf serum was necessary for the detection of induction by ATP of H2O2 production. The rate of H2O2 production induced by the addition of ATP increased in a dose-dependent manner, and the concentration of ATP required for half-maximum stimulation was about 10 mumol/l. ADP and GTP were also effective, but only at higher concentrations than ATP. In the absence of extracellular Ca2+, the production rate was very low. Production of H2O2 from thyroid cells was also measured by a method which discriminated between H2O2 and superoxide anion (O2-); in this, diacetyldeuteroheme-substituted HRP was employed as the trapping agent for both O2 metabolites. The thyroid cells produced H2O2, but not O2-, when the cells were stimulated by extracellular ATP.

Adenosine Triphosphate↗
PubMed1990

[Thyroid peroxidase].

Thyroid Peroxidase (TPO) is a key enzyme in the synthesis of thyroid hormone and is a major thyroid microsomal antigen corresponding to anti-microsomal autoantibodies in thyroid autoimmune diseases. We studied the autoantigenicity, thyroiditogenicity and gene structure of TPO. In micro-ELISA using human TPO as a target, all sera from patients with anti-microsomal antibodies contained IgG class of antibodies to TPO and some sera had IgM class of antibodies. The competitive inhibition test revealed that TPO is the major thyroid microsomal antigen. Experimental murine thyroiditis was successfully induced by the immunization of porcine TPO. Susceptibility of thyroiditis in each strain was very different from that of thyroiditis induced by thyroglobulin. T-cell line specific for porcine TPO could mediate thyroid lesions. Two kinds of full length cDNAs to human TPO were isolated from cDNA library which was constructed from mRNA purified from thyroid with Graves' disease. The longer one consisted of 3,048 nucleotides and its open-reading-frame was likely to encode 933 amino acids. The shorter one lacked 171 nucleotides at the middle portion of the longer one. The structure-gene for human TPO was located on 2q and consisted of 17 exons. One hundred and seventy-one nucleotides deleted in the shorter cDNA exactly corresponded to the 10th exon.

Animals↗
PubMed1989

Characterization of rat and human steroid sulfatases.

Rat and human steroid sulfatases were purified from liver and placenta, respectively, by the same procedure. The rat and human enzymes were solubilized with Triton X-100, and purified by immunoaffinity chromatography with a monoclonal antibody showing high binding activities to both the enzymes. They were further purified by high-pressure anion-exchange chromatography to compare their structural and catalytic properties. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that both enzymes had a molecular weight of 62,000. The enzymes had similar amino acid compositions and amino-terminal amino acid sequences. Significant differences of the optimum pH, Michaelis constant and maximum velocity were observed between these enzymes. The optimum pH of each enzyme varied from 6.0 to 8.0, depending on substrates and with or without Triton X-100. In detergent-free media, steroid sulfates competitively inhibited the ability of these enzymes to hydrolyze 4-nitrophenyl sulfate. In media containing Triton X-100, on the other hand, the inhibition types of the steroid sulfates on the hydrolyzing activities of the rat and human enzymes were noncompetitive- and mixed-types, respectively.

Amino Acid Sequence↗
PubMed1989

Thyroglobulin-mediated one- and two-electron oxidations of glutathione and ascorbate in thyroid peroxidase systems.

The one- or two-electron oxidation of thyroglobulin by the thyroid peroxidase system was found to be regulated by the iodine content of thyroglobulin. The catalytic intermediate of thyroid peroxidase observed at steady state of the reaction was Compound I and II when the iodine content in thyroglobulin was 0.2 and 0.7%, respectively, apparent rate constants for the rate-limiting steps being estimated at 4.7 x 10(7) and 4.8 x 10(4) M-1 S-1. The thyroglobulin-mediated oxidation of GSH occurred by way of two-electron transfer at 0.2% iodine content and by way of one-electron transfer at 0.7% iodine content. The spin-trapping experiment with 5,5-dimethyl-1-pyrroline-N-oxide showed that glutathione radicals were formed in the latter reaction but not in the former. In the reactions of thyroid peroxidase, the one- and two-electron oxidations of ascorbate were also mediated by 0.2 and 0.7% iodine thyroglobulins, respectively. The reactions were analyzed and mimicked with the use of p-cresol and p-acetaminophenol as a mediator in the reactions of lactoperoxidase and thyroid peroxidase.

Acetaminophen↗
PubMed1989

cDNA-directed expression of human thyroid peroxidase.

A human thyroid peroxidase cDNA, hTPO-1 [(1987) Proc. Natl. Acad. Sci. USA 84, 5555-5559], was expressed in human Hep G2 cells using a vaccinia virus cDNA-expression system. When examined by immunoblot analysis, the level of hTPO-1 protein expression reached a maximum approx. 24 h after infection and remained at a similar level up to 72 h post-infection. The expressed protein was enzymatically active as measured by guaiacol oxidation. Monoclonal antibody-assisted immunoaffinity column chromatography was used for partial purification of vaccinia-expressed hTPO-1, resulting in more than 300-fold higher specific activity and a measurable difference spectrum of the hTPO-1 (Fe3+)-CN complex.

Blotting, Western↗