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Biomedical subjects

M Katagiri

Publications and source records attributed to M Katagiri.

At least 181 records · Page 10Linked to original sources
PubMed1986

[Analysis of HLA-class II antigen mRNAs on T lymphoblasts].

The expression of human class II antigens on T lineage cells was analysed at the mRNA and the protein levels. Alpha- and beta-chains of class II antigens were identified on phytoheamagglutinin (PHA)-activated T lymphoblasts by two-dimensional polyacrylamide gel electrophoresis analysis. It was, however, not clear whether their spots represent HLA-DR, DQ or -DP antigen. Northern blot analysis using cDNA probes for alpha- and beta-chains of DR, DQ, and DP antigens revealed that mRNAs for all the class II antigen components were detected in PHA-activated T lymphoblasts. Among six T lymphoblastoid cell lines studied (Molt 4, RPMI 8402, CCRF-CEM, TALL 1, HSB 2 and MT-2), only MT-2, a human T cell leukemia virus-1 producing line, expressed class II antigen molecules and their mRNAs. The rest of the lines did not express class II antigens either at the protein level or at the mRNA level. However, Southern hybridization showed that these cell lines retained DQ beta-chain gene at the DNA level.

Antibodies, Monoclonal↗
PubMed1986

[Studies on HLA-class I and class II antigen expression in cultured choriocarcinoma cell lines].

Eight choriocarcinoma cell lines (Two SCH and IMa, were established from non-gestational choriocarcinoma and the other six BeWo, JaR, JEG-3, GCH-1, NUC-1, and HCCM-5, were from gestational one) were investigated for HLA-Class I and Class II antigen expression by the immunofluorescence method using rabbit anti HLA-ABC serum, and by a radioimmunoassay inhibition best using monoclonal antibodies (W6/32: anti HLA-ABC, 7B6: anti HLA-Class II, and D1-4-10: anti HLA-DR). With respect to HLA-Class I antigen expression, only non-gestational SCH (gastric origin) showed a clear positive finding. The other non-gestational IMa (ovarian origin) was negative. Cell lines from gestational choriocarcinoma showed a slightly positive finding (negative by immunofluorescence but slightly positive by inhibition test), except for JaR which was negative. All cell lines examined in the present study were negative for HLA-Class II antigen. The present results show that the majority of the gestational choriocarcinoma cell lines may express very slight HLA-Class I antigens.

Cell Line↗
PubMed1985

[The effect of ketoconazole and some other inhibitors of steroidogenesis on P-450 11 beta-catalyzed reactions].

Ketoconazole (Nizoral), an orally active antimycotic agent with a broad spectrum, has been reported to interfere with steroidogenesis both in patient and in vivo rat studies. It has also been shown that the same drug inhibits some P-450--catalyzed reactions in adrenal cortex mitochondria. In the present work, we studied the inhibitory effect of Ketoconazole, along with some other known inhibitors of steroidogenesis, on the reconstituted steroid monooxygenase system, which consists of adrenodoxin, its reductase and P-450 11 beta as the protein components being purified from bovine adrenal cortex mitochondria. The results indicated that; Ketoconazole completely inhibited hydroxylation of deoxycorticosterone at the 11 beta-position to form corticosterone and at the 18-position to form 18-hydroxydeoxycorticosterone. The Ki value for Ketoconazole, calculated either from the 11 beta-hydroxylase reaction or the 18-hydroxylase reaction, was 0.56 microM, which was comparable to the value obtained for metyrapone in the same system. Ketoconazole also inhibited 18-hydroxylation of corticosterone to form 18-hydroxycorticosterone, with 50% inhibitory concentration of less than 0.03 microgram/ml. The corresponding value for this inhibitor in the deoxycorticosterone 18-hydroxylase reaction was found to be 0.3 microgram/ml. The contrast between these values for the two substrates is striking. Thus, in a series of reaction steps, the inhibitory effect of corticosterone to 18-hydroxycorticosterone was more potent than deoxycorticosterone to 18-hydroxycorticosterone reaction. Both trilostane and o, p'-DDD over the wide concentration range failed to inhibit any of the reconstituted P-450 11 beta system similar to those applied to the Ketoconazole study.(ABSTRACT TRUNCATED AT 250 WORDS)

18-Hydroxycorticosterone↗
PubMed1985

A new allodeterminant on HLA-DQ molecules carrying the DQw3 specificity.

The la subset that reacts with alloantiserum HON known to possess a strong anti-DRw53 activity was isolated from a 125I-labeled Ia preparation obtained from cells of RPMI 8057 cell line (DR1,4) and was found on peptide mapping to be lacking in the pattern characteristic of DR-like molecules carrying the DRw53 specificity and to display the structural features of DQ molecules, particularly those carrying the DQw3 specificity. Distribution analysis on a panel of selected la-positive cell lines indicated that the specificity involved is associated only with DR4 and DRw9, differing from the known DRw53 pattern (DR4, 7, and w9) and also from the known DQw3 pattern (DR4 and 5). Reciprocal sequential binding experiments demonstrated that the HON-defined specificity resides along with DQw3 specificity on the same molecules. Thus, HON alloantiserum possesses two different antibody activities; one directed to DRw53 specificity and another directed to a new DR4- and w9-associated DQ specificity.

Epitopes↗
PubMed1985

Kinetic properties of rat kidney D-amino acid oxidase associated with peroxisomes.

In contrast to hog kidney D-amino acid oxidase, the v vs s plots of D-amino acid oxidase in homogenized rat kidney did not have the form of a rectangular hyperbola, and showed an apparent negative cooperativity. After subcellular fractionation of rat kidney, both of the oxidases in the supernatant fraction and the peroxisomal fraction showed Michaelis-Menten type kinetics. The Km values for D-alanine and D-proline of the peroxisomal fraction were significantly lower than those of the supernatant fraction. The partially purified enzyme from the peroxisomal fraction showed the same kinetic properties as the supernatant fraction. These facts suggest that the two types of rat kidney D-amino acid oxidase were originally identical and that some interaction between the enzyme and peroxisomes is physiologically important for the function of the enzyme.

Alanine↗
PubMed1985

[The inhibitory effects of anti class II monoclonal antibodies against the proliferative response of autoreactive T-cell clone].

The role of human class II antigens in autologous mixed lymphocyte reaction (AMLR) was investigated. The AMLR between PBL as a responder and autologous EBV-transformed cells as a stimulator was inhibited by anti class II framework (7B6) and anti DR (DI-4) monoclonal antibodies. Among monoclonal antibodies specific to DQ antigens, only HKD12 showed an inhibitory effect on AMLR. Of the autoreactive T-cell clones generated by AMLR, I-3 was peculiar; its proliferative response to autologous cells was inhibited only by HKD12. The inhibitory effect of HKD12 against AMLR or I-3 clone appeared to be epitope-specific. First, the result of sequential coprecipitation assay revealed that HKD12 reacted only a part of DQ antigen. Second, HKD12 did not inhibit allogeneic MLR. Third, the proliferative response of the I-3 clone was not inhibited by 7B6 which exerted a strong inhibitory effect on the proliferative response of autoreactive T-cell clones other than I-3 as well as allogeneic MLR.

Animals↗
PubMed1985

[A case of pentalogy of Fallot with numerous collaterals evaluated by magnetic resonance imaging: a report of an adult case].

In this report, the diagnostic value of magnetic resonance imaging (MRI) was compared with that of two-dimensional echocardiography, computed tomography and cardiac catheterization in a patient with pentalogy of Fallot who survived to her fortieth year. The advantages and disadvantages of MRI in diagnosing the present case were as follows: The cardiovascular system, with the exception of atrial septal defect, was evaluated precisely. Collateral vessels were detected using MRI, but impossible with other non-invasive methods. MRI was particularly suitable for imaging the cardiovascular system because of the high contrast between the lower intensity signal of the blood and higher intensity signal of the myocardium and blood vessel walls. Using MRI, data acquisition time was 1.5 min per section. Gated MRI required more time for data acquisition. However, various oblique tomographic projections and very clear static images could be obtained using gated MRI. MRI should be one of the best diagnostic techniques for diagnosing congenital heart disease.

Adult↗
PubMed1984

Multiple catalytic properties of the purified and reconstituted cytochrome P-450 (P-450sccII) system of pig testis microsomes.

The catalytic properties of the testis microsomal P-450, termed P-450sccII, have been studied in a refined assay system which consists of P-450sccII (13 nmol of P-450 heme/mg of protein) and its reductase has been purified extensively from pig testis. The results indicated that P-450sccII was highly active in catalyzing hydroxylation of 11 beta-hydroxyprogesterone at the 17 alpha-position to give 21-deoxycortisol and cleavage of 17 alpha-hydroxyprogesterone at the 17-20 bond to give androstenedione with turnover numbers of 25 and 30 mol/min X mol of P-450, respectively. In contrast, many physiologically important corticosteroids we tested were found to be poor substrates for both the hydroxylase and lyase reactions. The possible reason for the importance of these substrate specificity of P-450sccII in production of both corticosteroids and androgens in the endocrine tissues is discussed. P-450sccII also catalyzed conversion of testosterone to androstenedione, but 18O experiments failed to show incorporation of atmospheric oxygen into the androstenedione formed. However, this does not preclude the possibility that the P-450-bound intermediate gem-diol stereoselectively dehydrates to give the nonlabeled ketosteroid. In addition to these steroid-oxidizing activities, P-450sccII revealed considerable specificities toward various xenobiotics, suggesting that P-450sccII and liver microsomal P-450 are basically similar as regards enzymatic functions and activities.

Adrenal Cortex Hormones↗