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Biomedical subjects

N Itoh

Publications and source records attributed to N Itoh.

At least 379 records · Page 21Linked to original sources
PubMed1992

A variety of catalases and bromoperoxidases in genus Pseudomonas and their characterization.

A survey of bromoperoxidase in some Pseudomonas strains revealed that they contain different types of bromoperoxidase, catalase-bromoperoxidase and catalase. Although all Pseudomonas strains exhibited catalase activity, the enzyme isolated from P. pyrrolnitrica was named catalase-bromoperoxidase, because it catalyzed not only a catalase reaction, but also the bromination of monochlorodimedone. Except heme-type catalase-bromoperoxidase, this strain contained four isoenzymes of general nonheme bromoperoxidase, and their molecular weights were about 73,000. On the other hand, P. putida and P. aeruginosa had the usual heme-type catalase, but they differed in molecular weight and pI value. Both strains also had a nonheme bromoperoxidase which catalyzed the bromination of monochlorodimedone and aniline, and the molecular weight of each enzyme was 68,000 for P. putida and 86,000 for P. aeruginosa. Considering the results reported by Van Pée et al. [1] and Weisner et al. [2], regarding the haloperoxidases of Pseudomonas, the genus was revealed to contain a wide variety of bromoperoxidase and catalase.

Catalase↗
PubMed1992

mRNA capping enzyme. Isolation and characterization of the gene encoding mRNA guanylytransferase subunit from Saccharomyces cerevisiae.

The highly purified yeast mRNA capping enzyme is composed of two separate chains of 52 (alpha) and 80 kDa (beta), responsible for the activities of mRNA guanylyltransferase and RNA 5'-triphosphatase, respectively (Itoh, N., Yamada, H., Kaziro, Y., and Mizumoto, K. (1987) J. Biol. Chem. 262, 1989-1995). The gene encoding the mRNA guanylyltransferase subunit (alpha subunit), CEG1, has been isolated by immunological screening of a yeast genomic expression library in lambda gt11 with polyclonal antibodies directed against purified yeast capping enzyme. The identity of CEG1 was confirmed by epitope selection and by expressing the gene in Escherichia coli to give a catalytically active mRNA guanylyltransferase. The gene is present in one copy per haploid genome, and encodes a polypeptide of 459 amino acid residues. From its primary structure as well as its mRNA size, it was concluded that the alpha and the beta subunits of yeast mRNA capping enzyme are encoded by two separate genes, not as a fused protein. CEG1 is located on the chromosome VII by a pulse-field gel electrophoresis. Gene disruption experiment indicated that CEG1 is essential for the growth of yeast. We have also found another open reading frame (ORF2) which lies in close proximity to CEG1 in our clones and encodes a 450 amino acid-polypeptide of yet unknown function.

Amino Acid Sequence↗
PubMed1992

Expression of a functional asialoglycoprotein receptor through transfection of a cloned cDNA that encodes a macrophage lectin.

The Gal/GalNAc-specific lectin on rat peritoneal macrophages (macrophage asialoglycoprotein binding protein, M-ASGP-BP) is structurally similar to rat hepatic asialoglycoprotein-binding protein (ASGP-BP) or rat hepatic lectin (RHL) and is highly homologous with the major component of RHL, RHL-1 (Ii, M, Kurata, H., Itoh, N., Yamashina, I., and Kawasaki, T. (1990) J. Biol. Chem. 265, 11295-11298). We found in this study that transfection with a cDNA clone that encodes a single polypeptide, M-ASGP-BP, was sufficient for the expression of an endocytic receptor for asialoorosomucoid (ASOR) on the COS-1 cell surface. The Kuptake value for ASOR for the transfected cells was 12.5 nM, which is similar to that for peritoneal macrophages (23 nM), and the number of ASOR bound on the cell surface was 1-8 x 10(5)/cell, this value being hundreds of times larger than that for peritoneal macrophages. 125I-ASOR bound on the surfaces of the transfected cells was rapidly internalized on incubation at 37 degrees C, and after 90 min of incubation, most of the radioactivity was recovered in acid-soluble degraded products from the medium. These results confirmed that the cDNA cloned in our previous study does in fact encode M-ASGP-BP and also that the single polypeptide chain can form a homooligomeric receptor (probably a hexamer or octamer) exhibiting high affinity for ASOR. The latter property was distinct from that of the hepatic ASGP-BP in that simultaneous transfection of two cloned cDNAs that encode RHL-1 and RHL-2/3 was required to produce an active ASOR receptor (McPhaul, M., and Berg, P. (1986) Proc. Natl. Acad. Sci. U. S. A. 83, 8863-8867). This M-ASGP-BP expression system may serve as a simple model with which to investigate the molecular mechanisms underlying carbohydrate-mediated endocytosis.

Animals↗
PubMed1992

Tissue-specific expression of the rat secretin precursor gene.

Secretin is a 27-amino acid gastrointestinal hormone that stimulates the secretion of bicarbonate-rich pancreatic fluid. We previously demonstrated that the secretin precursor gene is expressed in the brain as well as in the small intestine. In this study, we demonstrated that the abundance of secretin precursor mRNA in the heart, lung, and kidney was comparable to that of the small intestine. The nucleotide sequences of the coding regions of the secretin precursor mRNAs in these tissues were identical to those of the small intestine, indicating that secretin precursor proteins produced in these tissues are identical to those in the small intestine. This is the first report that the secretin precursor gene is also expressed in the heart, lung, kidney, and testis as well as in the gastrointestinal tract and brain.

Animals↗
PubMed1992

[A case of latent Addison's disease with hypogonadotropic hypogonadism and dwarfism].

A case of latent Addison's disease accompanied by hypogonadotropic hypogonadism and dwarfism is described. A 20-year-old man was admitted to our department complaining of short stature and immature development of the external genitalia. Pigmentation was most evident on the fingers and face. Endocrinologically, serum ACTH level was very high, and serum cortisol level was in the lower limit of the normal range. Serum aldosterone and adrenal androgen levels were below their normal ranges. Based on these clinical and laboratory findings, the patient was diagnosed as having latent Addison's disease. Serum LH did not respond to a bolus injection of LH-RH. However, after 3 days administration of LH-RH, the response of serum LH to a bolus injection of LH-RH was enhanced. Serum testosterone level was not increased after the administration of hCG. These findings suggested a hypothalamic cause for the hypogonadism. It was indicated that short stature was apparently caused by GH neurosecretory dysfunction, since nocturnal GH secretion was below that in normal males and the response of GH to the administration of arginine was normal. In regard to the thyroid function, the peak of serum TSH after a bolus injection of TRH was delayed compared with normal subjects, and although serum T4 level was high, the basal metabolic rate was very low. This suggests that there is tissue resistance to the elevated thyroid hormone.

Addison Disease↗
PubMed1992

The cDNA structure, expression, and chromosomal assignment of the mouse Fas antigen.

The cell surface Fas antigen is a membrane-associated polypeptide which can mediate apoptosis. cDNA clones encoding the Fas antigen were isolated from a cDNA library constructed with mRNA from the mouse macrophage cell line BAM3. The nucleotide sequence and the deduced amino acid sequence of the mouse Fas antigen were 58.5 and 49.3% identical, respectively, to the corresponding sequences of human Fas antigen cDNA. The mouse Fas antigen consists of 306 amino acids with a calculated Mr of 34,971 and contains a single transmembrane domain which divides the molecule into extracellular and cytoplasmic domains. A 2.1-kb mRNA coding for the Fas antigen was detected in the mouse thymus, heart, liver, and ovary but not in brain and spleen. The expression of the Fas antigen gene in mouse fibroblast L929 and macrophage BAM3 cell lines was significantly induced by treatment with IFN-gamma but not by IFN-alpha/beta. Interspecific backcross analysis indicated that the gene coding for the Fas antigen is in the distal region of mouse chromosome 19.

Amino Acid Sequence↗
PubMed1992

Increased uptake of T-kininogen by the liver in inflammatory conditions.

The distribution of [125I]T-kininogen in the liver of rats was found to be increased by laparotomy-, turpentine- or lipopolysaccharide-induced inflammation, whereas no such increase was observed in other organs or when 125I-labeled carboxymethylated T-kininogen, which does not inhibit cysteine proteinase, was used. These results suggest that the liver plays an important role in clearing T-kininogen from the circulation during inflammation.

Animals↗
PubMed1992

Localization of laminin in nephritic glomeruli as revealed by a quick-freezing and deep-etching method with immunohistochemistry.

The three-dimensional localization of laminin in rat glomeruli at the chronic phase of Masugi nephritis was investigated by a quick-freezing and deep-etching method combined with immunohistochemistry. Light-microscopically, laminin was localized in increased mesangial matrix and thickened glomerular basement membrane. The quick-freezing and deep-etching method revealed that the increased mesangial matrix, which was newly formed in axial portions and areas of mesangial interposition, was composed of fine fibrillar networks. They were revealed with the 3,3'-diaminobenzidine tetrahydrochloride (DAB) reaction products of peroxidase-labelled secondary antibody following anti-laminin antibody. However, these reaction products were not uniformly distributed in the newly formed matrix. Although the fibrils organizing lamina densa were also immunostained with anti-laminin antibody, the fibrils connected to mesangial cells, podocytes and endothelial cells had smaller amounts of DAB reaction products for laminin. These results indicate that one of the components of fibrils in the mesangial matrix and lamina densa is laminin, which is heterogeneously distributed in the newly formed matrix.

3,3'-Diaminobenzidine↗
PubMed1992

The features of glomerulitis in the acute stage of panarteritis nodosa. Developmental process of glomerulitis and correlation between glomerular and vascular lesions.

In order to determine the morphological characteristics of certain vascular and glomerular lesions and the correlation between them, we attempted three-dimensional observation using serial sections of an autopsy kidney, from a patient with panarteritis nodosa in the acute phase. Fibrinoid necrotizing vasculitis spread from arcuate arteries to arterioles in a segmental, eccentric pattern, especially occurring at bifurcations. Segmental arteriolitis often originated in extraglomerular capsular arteriole and spread into the intraglomerular capsular arteriole and glomerular capillaries, directly leading to necrotizing glomerulitis. Some of the glomerulitis connected directly with extracapsular arteriolitis was segmental and eccentric in distribution. Most of the glomerulitis had a tendency to originate in the hilar arteriole, which was near bifurcations between the arteriole and glomerular capillaries. Segmental glomerulitis was found to consist of four elements: glomerular tuft necrosis with fibrin exudation, crescents, rupture or dissolution of Bowman's capsule, and pericapsulitis. It is suggested that the segmental inflammatory attacks, repeated more than twice, give rise to widespread and almost global necrotizing glomerulitis.

Acute Disease↗
PubMed1992

Induction of avascular yolk sac due to reduction of basic fibroblast growth factor by retinoic acid in mice.

Vasculogenesis depends on autocrine secretion of basic fibroblast growth factor (bFGF) from capillary endothelial cells. Retinoic acid (RA) induced avascular yolk sac (AVY) of mouse embryos of dams given 60 mg/kg of RA orally on Day 8 of gestation and sacrificed 3 days later. We studied the localization and transcriptional expression of bFGF and FGF-receptor (flg), heparin-binding growth factor (HBGF) activity, localization of lysosomal enzymes and alpha 1-antitrypsin (AAT), and electron microscopy of the normal mouse visceral yolk sac (VYS) and AVY. bFGF, which is normally present in the endoderm of the VYS of 8-day-old embryos and in all components of the VYS by Day 11 of gestation, was reduced in the AVY. However, in the presence of bFGF in vitro capillary nets were restored in the AVY. The mRNA for bFGF was not detectable in either VYS or AVY, while flg mRNA was detected equally in both organs in Northern blotting. The characteristic distribution pattern of lysosomal enzymes, acid phosphatase, lysozyme, and cathepsin D, and AAT was altered in the AVY. The level of acid phosphatase and AAT was reduced to 10% in the AVY. Electron microscopy revealed a partial or total loss of lysosomal membranes where the contents of lysosomes fused with adjacent lysosomes and the external organelles. These results suggest that vitelline blood vessels are not developed by endogenous autocrine bFGF but by exogenous transcellular bFGF from absorptive endodermal cells. Retinoic acid does not affect the angiogenic capacity of the VYS mesenchyme but destroys lysosomes, which release hydrolytic enzymes, leading to degradation of AAT in the endodermal cells and then digestion of endocytosed bFGF.

Acid Phosphatase↗
PubMed1992

Squamous cell carcinoma-associated antigen in uroepithelial carcinoma.

We investigated the clinical significance of squamous cell carcinoma (SCC) antigen determined by radioimmunoassay on patients with uroepithelial carcinoma. Serum SCC antigen levels and the positive rates were significantly higher in uroepithelial carcinoma having an SCC component than in normal controls, benign urologic diseases, other urogenital carcinomas, or in pure transitional cell carcinoma (TCC) of uroepithelial carcinomas. A substantial number of patients with pure TCC showed a positive serum level of SCC antigen. Immunohistochemical staining of SCC antigen on the uroepithelial carcinomas confirmed that some, not all, pure TCC, mostly grade 3, expressed SCC antigen in their cells. These results suggested a biologic characteristic of grade 3 TCC which is closely related to that of SCC. The serum levels of SCC antigen correlated well with the disease extensions in uroepithelial carcinoma containing SCC component. Changes in serum levels of SCC antigen following treatment reflected the clinical courses of patients, particularly in those with elevated pretreatment levels. The results of our study indicated that the determination of SCC antigen would be clinically useful for monitoring clinical courses of patients with uroepithelial carcinomas containing SCC component and of those with pure TCC whose pretreatment level was elevated.

Antigens, Neoplasm↗
PubMed1992

Neoadjuvant intraarterial infusion chemotherapy with a combination of mitomycin-C, vincristine, and cisplatin for locally advanced cervical cancer: a preliminary report.

Combination chemotherapy including cisplatin was administered intraarterially from the internal iliac artery as neoadjuvant chemotherapy to six patients with locally advanced uterine cervical cancer (stage higher than IIIB of FIGO). The drugs and doses were mitomycin-C 10 mg/m2, vincristine 1 mg/m2, and cisplatin 50 mg/m2. Two or three courses were repeated at intervals of 3 weeks. In three patients, dose reductions were undertaken for decreased renal function and thrombocytopenia. Partial response was, however, observed in all patients (response rate 100%), and five of six patients were able to undergo a radical hysterectomy. The major toxic effects were leukocytopenia, nausea, and vomiting. Our preliminary experience suggests that pelvic intraarterial infusion of combination chemotherapy is effective against primary and advanced uterine cervical cancer, and this preoperative treatment can lead to easier radical hysterectomy. However, further studies are warranted.

Aged↗
PubMed1992

Expression of interleukin-1 (IL-1) beta messenger ribonucleic acid (mRNA) and IL-1 receptor antagonist mRNA in peritoneal macrophages from patients with endometriosis.

OBJECTIVE: To investigate the expression of interleukin-1 (IL-1) beta messenger ribonucleic acid (mRNA) and IL-1 receptor antagonist (IL-1ra) mRNA in peritoneal macrophages. DESIGN, SETTING: Peritoneal fluid (PF) samples were collected from patients who underwent laparoscopy or laparotomy. Northern blot analysis was performed at the reproductive research laboratory. PATIENTS: Twenty-six patients with endometriosis, 10 patients with postinflammatory pelvic adhesion, and 12 control women with normal pelvis. MAIN OUTCOME MEASURE: Polyadenylated RNA isolated from peritoneal macrophages was analyzed on Northern blots by using synthetic oligonucleotide probes. RESULTS: The level of IL-1 beta mRNA expression was elevated in the group with stage I endometriosis, whereas the increased expression of IL-1ra mRNA was observed in the group with stages III and IV endometriosis. The level of IL-1 beta mRNA showed a positive correlation with that of IL-1 beta in PF and a negative correlation with the level of IL-1ra mRNA. CONCLUSIONS: Our results suggest that peritoneal macrophages express IL-1ra mRNA rather than IL-1 beta mRNA with the progress of endometriosis and that peritoneal macrophages may secrete IL-1ra protein that modulates the effects of IL-1.

Adult↗
PubMed1992

Adrenocortical carcinoma in a child with specific pedigree of family associated with cancer aggregation.

We report on a 5-year-old boy with functioning adrenocortical carcinoma as a proband of a specific pedigree with several young family members who had cancer. Most of the members who died of cancer had early onset of osteosarcoma, hepatoblastoma or malignant lymphoma. The finding of cancer aggregation in the family corresponded to the criteria for the cancer family syndrome.

Adrenal Cortex Neoplasms↗