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M Yoshihama

Publications and source records attributed to M Yoshihama.

At least 19 recordsLinked to original sources
PubMed2001

The analyses of 17beta-hydroxysteroid dehydrogenase isozymes in human endometrial hyperplasia and carcinoma.

Intratumoral metabolism and synthesis of estrogens are considered to play very important roles in the pathogenesis and development of human endometrial adenocarcinoma. The 17beta-hydroxysteroid dehydrogenase (17beta-HSD) isozymes catalyze the interconversion of estradiol (E2) and estrone and thereby serve to modulate the tissue levels of bioactive E2. To elucidate the possible involvement of this enzyme in human endometrial carcinoma, we first examined the expression of 17beta-HSD type 1 and type 2 in 20 normal cycling human endometria, 36 endometrial hyperplasia, and 46 endometrial endometrioid adenocarcinoma using immunohistochemistry, and we then studied immunoreactivity of 17beta-HSD type 2 using immunoblotting analyses, the activity of 17beta-HSD type 1 and type 2 using thin-layer chromatography and their expression using RT-PCR in endometrial endometrioid adenocarcinoma. We correlated these findings with various clinicopathological parameters to examine the biological significance of 17beta-HSDs in human endometrial disorders. 17beta-HSD type 2 immunoreactivity in normal endometrium was present in all cases of secretory phase (n = 14), but not in any endometrial mucosa of proliferative phase (n = 6). In addition, 17beta-HSD type 2 immunoreactivity was detected in 27 of 36 (75%) endometrial hyperplasia and 17 of 46 (37%) carcinoma cases. 17beta-HSD type 1 immunoreactivity was not detected in all the cases examined. In both endometrial hyperplasia and carcinoma cases there were significant positive correlations between 17beta-HSD type 2 and progesterone receptor labeling index (LI). In carcinoma cases, a significant inverse correlation was detected between 17beta-HSD type 2 immunoreactivity and age. In addition, 17beta-HSD type 2 immunoreactivity was also correlated with 17beta-HSD type 2 enzymatic activity, and semiquantitative analyses of 17beta-HSD type 2 messenger RNA. No significant correlations were detected between 17beta-HSD type 2 and estrogen receptor LI, Ki67 LI, amount of aromatase messenger RNA or histological grade. These data indicated that the expression of 17beta-HSD type 2 in hyperplastic and/or neoplastic endometrium may represent altered cellular features through hyperplastic and neoplastic transformation. However, 17beta-HSD type 2 may also play some protective and/or suppressive roles toward unopposed estrogenic effects through inactivating E2 in situ, especially in premenopausal patients.

17-Hydroxysteroid Dehydrogenases↗
PubMed2001

17 beta-Hydroxysteroid dehydrogenase type 2 expression and enzyme activity in the human gastrointestinal tract.

The 17 beta-hydroxysteroid dehydrogenases (17 beta HSDs) play an important role in the regulation of intracellular levels of biologically active sex steroid hormones in various human tissues. To date, eight distinctive 17 beta HSD enzymes have been cloned and characterized in humans. Among these isoenzymes, 17 beta HSD type 2 (17 beta HSD2) catalyses the conversion of testosterone into androstenedione and/or oestradiol into oestrone in various tissues, and it has thus been suggested to be involved in the biological inactivation of these sex steroids. The human gastrointestinal tract and liver are considered as the principle sites of inactivation and metabolism of various forms of orally administered sex steroids. We therefore examined 17 beta HSD2 expression and activity in human adult non-pathological gastrointestinal tract in order to clarify further the biological significance of this enzyme. A total of 80 specimens (40 from males and 40 from females) of normal oesophageal, stomach, duodenal, ileal, colonic and rectal tissues were examined for immunohistochemistry. Altogether, 17 tissue specimens were used for enzyme assay, and eight for RNA analysis. 17 beta HSD2 activity was detected in the stomach, duodenum, ileum, colon and rectum. 17 beta HSD2 mRNA was most abundant in the small intestine. 17 beta HSD2 immunoreactivity was localized almost exclusively to the absorptive epithelium, which may be involved in the inactivation of excessive endogenous and exogenous active sex steroids. Results from the present study thus suggest that the human gastrointestinal tract is an important sex steroid metabolizing organ in humans.

17-Hydroxysteroid Dehydrogenases↗
PubMed2000

The human ribosomal protein L6 gene in a critical region for Noonan syndrome.

We have determined the genomic structure of the human ribosomal protein L6 gene (RPL6) and assigned it to the interval containing the Noonan syndrome locus. RPL6 spans 4415bp and consists of seven exons and six introns. The first exon is only 19bp in length, containing a 5' non-coding region and a polypyrimidine tract. The second exon starts with the initiator ATG. Although the overall structure of the protein is highly conserved among mammalian species, there is significant variation in the N-terminal portion. We have refined the position of RPL6, using two different radiation hybrid panels. RPL6 was mapped to chromosome 12q24.1 between the markers D12S84 and D12S861, which is in the critical region for Noonan syndrome.

Amino Acid Sequence↗
PubMed2000

17beta-hydroxysteroid dehydrogenase type 1 and 2 expression in the human fetus.

The present study investigates the expression patterns of 17beta-hydroxysteroid dehydrogenase (17betaHSD) isozymes in human fetal tissues to understand how estrogenic activity is regulated in the human fetus. Using enzyme assay, high 17betaHSD activity was detected in the placenta and liver, and low levels of 17betaHSD activity were also present in the gastrointestinal tract and kidney. After Northern blot analysis, we detected the messenger ribonucleic acid for 17betaHSD type 1 (17betaHSD1) only in the placenta, whereas that for 17betaHSD type 2 (17betaHSD2) was detected in the placenta, liver, gastrointestinal tract, and urinary tract at 20 gestational weeks. In RT-PCR analysis of the messenger ribonucleic acid transcripts, 17betaHSD 1 was predominantly expressed in the placenta, brain, heart, lung, and adrenal, whereas 17betaHSD2 expression was predominantly detected in the liver, gastrointestinal tract, and kidney. In addition, we detected 17betaHSD2 immunoreactive protein in surface epithelial cells of the stomach, absorptive epithelial cells of the small intestine and colon, hepatocytes of the liver, and interstitial cells surrounding the urinary tubules of the renal medulla. 17betaHSD2 in these tissues may be functioning in the prevention of in utero exposure of the fetus to excessive estradiol from the maternal circulation and amniotic fluids.

17-Hydroxysteroid Dehydrogenases↗
PubMed1999

Gene organization and sequence of the region containing the ribosomal protein genes RPL13A and RPS11 in the human genome and conserved features in the mouse genome.

We have determined the organization and sequence of the region containing two ribosomal protein (rp) genes in the human and mouse genomes. The two genes, human RPL13A and RPS11, and mouse Rpl13a and Rps11, are tandemly located in both genomes with an interval of only 4.6kb in the case of the human genes and 1.6kb in the case of the mouse genes. The human RPL13A and RPS11 are 4236bp and 3254bp in length and comprise eight and five exons respectively, whereas the mouse Rps11 is 1951bp long and has five exons. Structural comparison of these genes, including previously reported mouse Rpl13a, revealed a significant conservation of sequences in the promoter regions. Although most rp genes are dispersed throughout the human genome, the conserved features and adjacent localization indicate possible coordinate transcription of the two genes. Furthermore, we have found that four small nucleolar RNA (snoRNA) genes are located in the introns of the two rp genes, both human and mouse. U32, U33, and U34 snoRNAs are encoded in introns 2, 4, and 5 of RPL13A respectively, and U35 in the sixth intron of RPL13A and the third intron of RPS11. The same organization of these snoRNA genes was also observed in the case of the mouse genes.

Animals↗
PubMed1999

Effects of aromatase inhibitors on the pathobiology of the human breast, endometrial and ovarian carcinoma.

It is very important to examine the influence of inhibition of in situ estrogen production on the pathobiology of human sex steroid-dependent tumors in order to understand the clinical effects of aromatase inhibitors. We have examined the biological changes before and after aromatase inhibitor treatment in vitro (endometrial and ovarian cancer) and in vivo (breast cancer). First, we analyzed these changes using histoculture of 15 human endometrial cancers and 9 ovarian cancers. Five of the fifteen endometrial cancers and four of the nine ovarian cancers demonstrated decreased [3H]thymidine uptake or Ki67 labeling index after 14alpha-hydroxy-4-androstene-3,6,17-trione (NKS01) treatment. In ovarian cancer cases, the responsive cases tended to be associated with higher aromatase and estrogen receptor alpha (ER) expression compared with the other cases but this was not seen in the endometrial cancer cases. There were no changes in ER and aromatase expression before and after NKS01 treatment in either ovarian or endometrial cancer cases. We then studied the same primary human breast tumors before and after aminoglutethimide (AMG, n=3) and 4-hydroxyandrostenedione (4-OHA, n=3) treatment. Tumor aromatase activity increased in 3 cases and decreased or was unchanged in 3 cases but aromatase immunoreactivity in stroma and adipocytes was unaltered in 5 cases. There were no changes in the ER labeling index before or after treatment. Five of the six cases including the responsive cases tended to be associated with decreased cell proliferation or Ki67 expression and increased apoptosis when examined by the TUNEL method. These results indicate that aromatase inhibitors may exert their effects on human breast and other cancers through decreasing proliferation and increasing apoptosis, possibly without altering ER status.

Antineoplastic Agents↗
PubMed1999

New types of liposidomycins produced by Streptomyces that inhibit bacterial peptidoglycan synthesis. Structure elucidation of fatty acid components by tandem mass spectrometry.

The structures of the fatty acid components of various new liposidomycins were determined using tandem mass spectrometry; the negative FAB/MS/MS/MS technique for liposidomycins with a 3-methylglutaric acid moiety and the negative FAB/MS/MS technique for liposidomycins without a 3-methylglutaric acid moiey. This structural information was obtained by analysis of peaks due to charge-remote fragmentations for 3-hydroxycarboxylate anions or carboxylate anions which were generated from liposidomycin molecules in a mass spectrometer. The MS/MS/MS technique that can exclude the matrix-derived and/or interfering ions showed higher sensitivity than the MS/MS technique.

Aminoglycosides↗
PubMed1998

Identification of the major allergens in wheat flour responsible for baker's asthma.

Baker's asthma, a typical occupational allergic disease, is a serious problem in the food industries. In this study, purification and identification of major allergens recognized by IgEs in sera of allergic patients were performed. Major immunoreactive proteins were purified from the albumin fraction by gel filtration on a Toyopearl HW-50 column followed by reverse-phase HPLC. The N-terminal amino acid sequences and molecular masses measured by MS indicated that the major immunoreactive proteins are members of the alpha-amylase inhibitor family, 0.19 and 0.28. Significant leukotriene release by each purified protein was observed in cell-associated stimulation tests, suggesting in vivo activity of these antigens. Carbohydrate analyses of major allergens indicated that they are monoglycosylated but not N-glycosylated in spite of the presence of a potential N-glycosylation site. Recombinant 0.19 expressed in Escherichia coli showed the same reactivity with IgE as native wheat 0.19 in Western blotting and ELISA using methyl vinyl ether maleic anhydride co-polymer as an immobilizing reagent, suggesting that the allergenic epitopes are located in the peptide portions.

Allergens↗
PubMed1998

Selective inhibition of the bacterial peptidoglycan biosynthesis by the new types of liposidomycins.

We examined the inhibitory activity against bacterial peptidoglycan biosynthesis, mammalian glycoprotein biosynthesis and growth of BALB/3T3 cells of four different types of liposidomycins which have the structure with or without sulfate and/or 3-methylglutaric acid moieties. Liposidomycins inhibited peptidoglycan biosynthesis about 30 to 500 times more effectively than tunicamycin, whereas liposidomycins inhibited mammalian glycoprotein biosynthesis about 30 to 300 times less effectively than tunicamycin. When the cytotoxic effect of liposidomycins and tunicamycin on the growth of mammalian cells were compared, liposidomycins did not show toxicity against BALB/3T3 cell at 25 microg/ml, though tunicamycin inhibited cell growth by 50% at 0.05 microg/ml. On the basis of these results, it is concluded that liposidomycins are selective antibiotics showing highly specific inhibition toward bacterial peptidoglycan biosynthesis.

3T3 Cells↗
PubMed1998

New types of liposidomycins that inhibit bacterial peptidoglycan synthesis and are produced by Streptomyces. I. Producing organism and medium components.

Liposidomycins are atypical lipid-bearing nucleoside antibiotics that inhibit bacterial peptidoglycan synthesis. A producing strain was identified as a Streptomyces sp. from its cultural characteristics and physiological properties. It produced new types of liposidomycins that lacked sulfate and/or 3-methylglutaric acid moieties present in known liposidomycins by changing medium components. Sucrose and malt extract were particularly suitable sources for specific production of the new types of liposidomycins.

Aminoglycosides↗
PubMed1998

New types of liposidomycins that inhibit bacterial peptidoglycan synthesis and are produced by Streptomyces. II. Isolation and structure elucidation.

Various new liposidomycins were isolated from a culture of the strain Streptomyces sp. SN-1061M by changing medium components and they were classified into four types (I-IV) based on their structures. They were purified by butanol extraction, silica gel and LH-20 column chromatographies, and high performance liquid chromatography on ODS columns. Type (I) has the original structure which has sulfate and 3-methylglutaric acid moieties. Type (II) has no 3-methylglutaric acid moiety and type (III) has no sulfate moiety. Type (IV) has neither moiety. Type (III) and (IV) compounds, which have no sulfate moiety, exhibited more potent antimicrobial activity.

Aminoglycosides↗
PubMed1997

RKS-1778, a new mammalian cell-cycle inhibitor and a key intermediate of the [11]cytochalasin group.

In the course of screening for the mammalian cell-cycle inhibitors, we have isolated a new [11]cytochalasin, RKS-1778 (1), and epoxycytochalasin H (2) from a fungus, Phoma sp. SNF-1778. The structure of 1 was determined to be 21-acetoxy-18-hydroxy-10-phenyl-5,6,16,18- tetramethyl[11]cytochalasa-6,13,19-trien-1-one, one the basis of spectroscopic methods, including 1H- and 13C-2D NMR techniques, RKS-1778 (1) may be a precursor of 2 and the key direct product of a proposed biosynthetic intramolecular Diels-Alder reaction. Both 1 and 2 completely arrested the cell-cycle progression of tsFT210 cells in the M phase at concentrations of 2.1 and 2.0 microM, respectively.

Animals↗
PubMed1997

Prolyl endopeptidase inhibitors derived from actinomycetes.

Four prolyl endopeptidase inhibitors isolated from actinomycetes, named propeptin, SNA-8073-B, staurosporine, and enduracidin were classified into 3 groups on the basis of their inhibition potency against prolyl endopeptidase from a bacterium (Flavobacterium) and a mammal (human placenta). Staurosporine inhibited the enzyme from Flavobacterium more strongly than that from human placenta. Enduracidin inhibited the enzyme from human placenta more strongly than that from Flavobacterium. Propeptin and SNA-8073-B, both new compounds, inhibited the enzymes from both origins to the same extent.

Actinomycetaceae↗
PubMed1997

SNA-8073-B, a new isotetracenone antibiotic inhibits prolyl endopeptidase. I. Fermentation, isolation and biological properties.

SNA-8073-B, an inhibitor of prolyl endopeptidase isolated from the broth filtrate of Streptomyces sp. SNA-8073, is a new isotetracenone antibiotic. It was purified by ethyl acetate extraction, silica gel column chromatography and high performance liquid chromatography on ODS column. SNA-8073-B has the molecular formula of C20H16O5 and is a stereoisomer of SNA-8073-A (fujianmycin B, rubiginone A2). SNA-8073-B inhibited prolyl endopeptidase of Flavobacterium non-competitively (IC50 = 8.9 microM) when Z-Gly-Pro-pNA was used as a substrate, but SNA-8073-A did not show any inhibition even at 60 microM.

Anthraquinones↗
PubMed1997

Propeptin, a new inhibitor of prolyl endopeptidase produced by Microbispora. I. Fermentation, isolation and biological properties.

Propeptin, an inhibitor of the prolyl endopeptidase isolated from the mycelium of Microbispora sp. SNA-115, is an atypical cyclic peptide antibiotic. It was purified by column chromatographies on silica gel and Sephadex LH-20 and high performance liquid chromatography using an ODS column. Propeptin has the molecular formula of C113H142N26O27 and consists of nineteen amino acids. Propeptin inhibited prolyl endopeptidase of the genus Flavobacterium competitively when Z-Gly-Pro-pNA was used as a substrate. The inhibitor constant (Ki) was 0.70 microM.

Actinomycetales↗
PubMed1997

Inhibitory action of reveromycin A on TGF-alpha-dependent growth of ovarian carcinoma BG-1 in vitro and in vivo.

The antitumor effect of reveromycin A (RM-A), an inhibitor of EGF-dependent cell proliferation on murine and human tumor cell lines, was examined in vitro and in vivo, RM-A showed little antitumor effect against three murine tumors tested, but showed strong antitumor effect (a minimum treated/control ratio of 36%) against a human ovarian carcinoma BG-1, which is known to be a transforming growth factor alpha (TGF-alpha)-secreting and estrogen receptor-expressing cell line. In BG-1 cells, RM-A inhibited the cell proliferation induced by TGF-alpha at the concentration range 30-300 nM, but did not inhibit the proliferation induced by 17 beta-estradiol (E2).RM-A is a possible new antitumor drug with a novel mechanism of action and may also be a useful tool for the analysis of epidermal growth factor receptor (EGFR)-mediated cell proliferation in tumor cells.

Animals↗