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Biomedical subjects

M Katagiri

Publications and source records attributed to M Katagiri.

At least 163 records · Page 9Linked to original sources
PubMed1987

Effect of ketoconazole, etomidate and other inhibitors of steroidogenesis on cytochrome P-450sccII-catalyzed reactions.

The effects of a variety of certain inhibitors of adrenal steroidogenesis have been studied on the reconstituted C21-steroid 17 alpha-hydroxylase-17,20-lyase system, whose protein components, the enzyme 17 alpha-hydroxylase-17,20-lyase(P-450sccII) and its reductase, are extensively purified from pig testis microsomes. We found: (1) Ketoconazole (cis-1-acetyl-4-[4-((2-(2,4-dichlorophenyl)-2-(1H-imidazole-1- ylmethyl-1,3-dioxalan-4-ol)methoxy)phenyl] piperazine and Etomidate(R-(+)-ethyl-[1-(a-methyl-benzyl)-indol-5-carboxylatel), inhibited cleavage of 17 alpha-hydroxy progesterone at the 17,20-bond to give androstenedione in a dose-dependent fashion. (2) Some other inhibitors of steroidogenesis, Metyrapone (2-methyl-1.2di-3-pyridyl-1-propanone), Trilostane (4,5-epoxy-17-hydroxy-3-oxo androstane-2-carbonitrile),o,p'DDD (1-(O-chlorophenyl)-1-(p-chlorophenyl)2,2-dichloroethane) and Aminoglutethimide (p-(alpha-aminopheny)-alpha-ethylglutaramide) did not inhibit the same 17,20-lyase system. (3) All of the above listed inhibitors, over a wide variety of concentration ranges, had no significant effect on the 17 alpha-hydroxylation of 11 beta-hydroxyprogesterone, which had been shown to be catalyzed by the same P-450sccII. (4) NADPH:P-450 reductase was not inhibited by all of the above listed inhibitors.

Animals↗
PubMed1987

Significance of IgA deposits on the glomerular capillary walls in IgA nephropathy.

Based on immunofluorescence findings, 232 patients with IgA nephropathy were classified into two groups; one consisted of 88 patients (38%) with IgA deposits in the glomerular capillary walls together with the mesangial deposits (capillary type), and the other consisted of 144 patients (62%) with deposits confined to the mesangium (mesangial type). Electron microscopic findings revealed dense deposits on the capillary walls (subepithelial, 50%; intramembranous, 65%; and subendothelial, 24%) in 37 of 46 patients with capillary type and six of 47 with mesangial type (P less than .001). Crescent formation observed in greater than or equal to 10% of glomeruli was more frequently found in patients with the capillary type (30/88, 34%) than those with the mesangial type (9/144, 6%) (P less than .01), especially higher in those with subepithelial deposits (15/26, 57%). The capillary type patients showed heavier proteinuria (1.7 +/- 0.2 g/d) than the mesangial type patients (0.6 +/- 0.1 g/d) (P less than .05). Thirteen of the 14 patients in an acute exacerbation phase, manifested by an abrupt increase in urinary protein and development of macroscopic hematuria, showed capillary type IgA deposits. The ratio of patients with normal renal function in the fifth year after apparent onset was lower in the capillary type (74.0%) than in the mesangial type patients (96.9%) (P less than .05). These findings suggest that capillary IgA deposition is closely related to clinical and histologic activities of IgA nephropathy and is considered to be an important factor responsible for the progression of the disease, possibly through crescent formation.

Acute Disease↗
PubMed1987

Parathyroid adenoma imaged by gallium-67 citrate. A case report.

A parathyroid adenoma imaged by Ga-67 citrate in a 17-year-old man with primary hyperparathyroidism and a palpable solid tumor in the neck is presented. Although preoperative examination and intraoperative findings suggested a parathyroid carcinoma, histologic studies showed a parathyroid adenoma with predominant chief cell type.

Adenoma↗
PubMed1987

[On the mechanisms of human T cell proliferation induced by the 10B4 molecule].

The 10B4 system of human T cells seems to constitute a member of T cell receptor complex. We have analyzed the mechanisms by which a monoclonal antibody against the 10B4 molecule activates human peripheral T cells. The 10B4 antibody together with goat anti-mouse immunoglobulin antibody induced significant increase of DNA and RNA syntheses in T cells with peak responses on day 9 and on day 7, respectively. This activation process is mediated by interleukin 2 (IL-2) and its receptor (IL-2R), because (1) IL-2 activity was detected in the culture supernatants, (2) the percentage of IL-2R positive cells increased during the culture period, with a peak on day 9, and (3) the 10B4-induced T cell proliferation was inhibited by anti IL-2R antibody. Blocking studies with pharmacological agents showed that in the 10B4-induced system, a protein kinase C (PK-C) inhibitor, palmitoylcarnitine, blocked DNA synthesis, RNA synthesis, IL-2 production and IL-2R expression whereas a Ca ion channel blocker, verapamil, inhibited DNA synthesis, RNA synthesis, IL-2 production but not IL-2R expression. It is thus concluded that PK-C activation is required for IL-2 production and IL-2R expression and that channel-mediated Ca ion influx is important for IL-2 production but may not be needed for IL-2R expression.

Animals↗
PubMed1987

[Familial cardiomyopathy with different clinical features in individual members].

The mother and three children of a family whose parents were consanguineous, each had cardiomyopathy with various patterns of hypertrophy and dilatation. All members had asymmetrical septal hypertrophy (ASH), and three of them were characterized as hypertrophic cardiomyopathy (HCM). Another one had ventricular dilatation mimicking dilated cardiomyopathy (DCM). Case 1: The 57-year-old mother had a typical ASH pattern; her septal/posterior wall thickness ratio (IVST/LVPWT) was 2.5. Case 2: The 37-year-old daughter had basal septal hypertrophy. Case 3: The 32-year-old elder son had typical concentric hypertrophy. Case 4: The 30-year-old younger son had an episode of congestive heart failure, and showed DCM-like features with considerable dilatation and impaired wall motion of the left ventricle. The hypertrophic pattern in cardiomyopathies is thought to depend partially on the ages of the onset, or its evolution with aging.

Adult↗
PubMed1986

P-450(11beta)-dependent conversion of androgen to estrogen, the aromatase reaction.

Purified bovine adrenal P-450(11)beta has been shown to act as an aromatase which catalyzes conversion of 19-oxoandrostenedione to estrone. No conversions took place when any one of the required components such as NADPH, NADPH:adrenodoxin reductase, adrenodoxin and P-450(11)beta was omitted from the complete reconstituted system. P-450scc, another mitochondrial P-450 obtained from adrenal cortex, did not substitute for the P-450(11)beta in the aromatase reaction. These results show that P-450(11)beta is able to catalyze a series of reaction which can generate adrenal estrogen through androstenedione and its 19-hydroxy- and 19-oxo-derivatives. The P-450(11)beta-dependent reaction appears to be quite different from the placental aromatase reaction in that the latter is catalyzed by a microsomal P-450.

Androgens↗
PubMed1986

A role for Lyb-2 in B cell activation mediated by a B cell stimulatory factor.

The Lyb-2 system of the mouse is involved in regulation of a proliferative step in the differentiation of B cells responding to T-dependent antigen. The present study concerns the role of Lyb-2 in an early phase of B cell activation with respect to B cell receptor functions for activation factors. It is shown that interaction of monoclonal anti (alpha)-Lyb-2 antibody with Lyb-2 on the B cell surface induces B cell proliferation by synergistic action with B cell growth factor II-containing factor or interleukin 1. In contrast, alpha-Lyb-2 antibody could not synergize with the Con A-induced culture supernatant of T cell hybridoma FS6-14.13 (FS6) containing B cell stimulatory factor-1 (BSF-1; formerly called BCGF I), and the effect of combining the two was only additive on B cell proliferation. Absorption studies showed that BSF-1 in FS6 could be absorbed by unstimulated B cells, about 95% of which were at Go phase of the cell cycle, but not by thymocytes, and more importantly that alpha-Lyb-2 antibody blocked the absorption in an Lyb-2-specific manner, possibly by competing with BSF-1. It is thus likely that alpha-Lyb-2 antibody may interact with a BSF-1 receptor on B cells or a molecule closely associated with it. Interestingly, alpha-Lyb-2 antibody mimicked the action of BSF-1 in a costimulator assay with affinity-purified goat alpha-mouse IgM antibody, but could not replace all the activities ascribed to BSF-1. Possible mechanisms involved are discussed.

Animals↗
PubMed1986

Selective inhibition of lipopolysaccharide-induced polyclonal IgG response by monoclonal Ly-5 antibody.

We have identified two important molecules involved in the regulation of B cell differentiation, namely Lyb-2 and Ly-5. To gain further insight into the function of these two molecules, we examined the effect of monoclonal Lyb-2 and Ly-5 antibodies on lipopolysaccharide (LPS)-induced B cell growth and maturation. We found that Lyb-2 antibody does not have any effect on LPS-induced proliferation and on polyclonal IgM or total IgG responses. On the other hand, although Ly-5 antibody did not affect proliferation and polyclonal IgM responses, it strongly inhibited polyclonal IgG responses, presumably by direct action on B cells. This inhibition was not caused by direct suppressive effect of Ly-5 antibody or Fc receptor-mediated negative signaling. To exert maximal inhibitory effect, Ly-5 antibody had to be added to the culture during the initial 48 hr. However, the presence of Ly-5 antibody during the first 2 days did not cause a significant inhibition. It is thus likely that Ly-5 plays a critical role in the regulation of LPS-induced B cell maturation into IgG-secreting cells at a phase starting within 48 hr after LPS stimulation and continuing thereafter.

Animals↗
PubMed1986

P-45011 beta-dependent conversion of cortisol to cortisone, and 19-hydroxyandrostenedione to 19-oxoandrostenedione.

Purified bovine adrenal P-45011 beta has been shown to catalyze conversions of cortisol to cortisone (11-oxidase activity), and 19-hydroxyandrostenedione to 19-oxoandrostenedione (19-oxidase activity), in the reconstituted system consisting of NADPH, NADPH:adrenodoxin reductase, and adrenodoxin. The turnover numbers (mol of product formed/min/mol of P-450) were 1.2 for the 11-oxidase activity and 1.4 for the 19-oxidase activity. No reactions took place when any one of the electron-donating components were omitted either in the presence or in the absence of added NADP+. Likewise, rabbit antibody prepared against P-45011 beta immunoprecipitated the 11-oxidase activity with concomitant loss of deoxycorticosterone 11 beta-hydroxylase activity.

Adrenal Glands↗
PubMed1986

Partial N-terminal sequence analysis of DRw53 antigens: the beta-chains of DRw53 antigens are structurally distinct from beta-chains of DR and DQ antigens.

DRw53 antigens were isolated from DR7-homozygous and DRw9-homozygous cell lines with an alloantiserum, Hon, containing an anti-DRw53 alloantibody. Partial N-terminal sequence analysis of the isolated DRw53 antigens revealed that DRw53 alpha-chains have sequences indistinguishable from those of DR alpha-chains. In contrast, DRw53 beta-chains have sequences distinct from those of the DR beta-chains and DQ beta-chains isolated from the same cell lines. The DRw53 beta-chains are also distinct from DP beta-chains. These results suggest that the DRw53 beta-chains chains are products of a gene that has not yet been well characterized in the HLA-D region.

Amino Acid Sequence↗
PubMed1986

Expression of HLA class I and class II antigens in human choriocarcinoma cell lines.

Eight choriocarcinoma cell lines (6:gestational origin, 2:non-gestational origin) were studied by a radioimmune inhibition test using monoclonal antibodies for the expression of HLA class I and class II antigens. Levels of HLA class I antigens were very slight or nil. On the other hand, no HLA class II antigen was detected in any choriocarcinoma cell lines examined.

Antibodies, Monoclonal↗
PubMed1986

Effect of ketoconazole (an imidazole antimycotic agent) and other inhibitors of steroidogenesis on cytochrome P450-catalyzed reactions.

The effects of Ketoconazole, an orally active imidazole antimycotic agent, and other known inhibitors of steroidogenesis were examined in the reconstituted steroid monooxygenase system which consists of adrenodoxin, its reductase and purified P450. We found that: Ketoconazole completely inhibits the hydroxylation of deoxycorticosterone (DOC) at the 11 beta and 18-positions; Ketoconazole also inhibits the 18-hydroxylation reaction that converts corticosterone to form 18-hydroxycorticosterone; both Trilostane (4,5-epoxy-17-hydroxy-3-oxoandrostane-2-carbonitrile) and o,p'-DDD do not inhibit either the 11 beta or 18-hydroxylase activities of the reconstituted P450(11 beta) system (NADPH-adrenodoxin reductase activity is also not inhibited by either drug); Ketoconazole inhibits the conversion of cholesterol to pregnenolone in a dose-dependent fashion, and is a more potent inhibitor than metyrapone (2-methyl-1,2-di-3-pyridyl-1-propanone) in the P450scc-catalyzed reaction system; other inhibitors fail to show any inhibitory effects in this system.

18-Hydroxycorticosterone↗
PubMed1986

Molecular cloning and sequence analysis of full-length cDNA for rabbit liver NADPH-cytochrome P-450 reductase mRNA.

The nucleotide sequence of the mRNA for NADPH-cytochrome P-450 reductase from rabbit liver was determined from a full-length cDNA clone (pFP105). The clone contains 2,269 nucleotides complementary to rabbit liver reductase mRNA. The single open reading frame of 2,037 nucleotides codes for a 679-amino acid polypeptide with a calculated molecular weight of 76,583 daltons. The cloned cDNA contains the complete 3'-noncoding region of 193 nucleotides, including 68 nucleotides of poly(A), and 39 nucleotides of the 5'-noncoding region. The nucleotide sequence in the coding region of cDNA of rabbit reductase (pFP105) showed 85% homology to that of rat reductase (Porter, T.D. & Kasper, C.B. (1985) Proc. Natl. Acad. Sci. U.S. 82, 973-977, and Murakami, H. et al. (1986) DNA 5, 1-10). Rabbit reductase has one more amino acid residue than the rat enzyme, and the amino acid compositions of the two enzymes are similar. The amino acid sequence of the rabbit enzyme showed 91% identity with that of the rat enzyme. The segment related to binding of FMN and FAD was well conserved among rabbit, rat, and pig reductases. The sequence related to AMP moiety-binding was also conserved among these species, and was found in the amino acid sequence of NADH-cytochrome b5 reductase, another flavoenzyme in the microsomal electron transport system.

Amino Acid Sequence↗