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Biomedical subjects

N Itoh

Publications and source records attributed to N Itoh.

At least 343 records · Page 19Linked to original sources
PubMed1993

Two truncated forms of rat insulin receptor-related receptor.

The insulin receptor-related receptor (IRR) (1271 amino acids) is expected to have unique functions as a novel member of the insulin receptor family. In this paper, we report two alternatively spliced variants of rat IRR mRNA, which are predicted to encode two truncated forms of IRR, sIRR-1 (410 amino acids) and sIRR-2 (469 amino acids). The amino acid sequence of sIRR-1 is identical to the N-terminal 410-amino acid sequence of IRR. sIRR-2 has an additional 59-amino acid insertion in the C-terminal region. Both truncated forms retain the N-terminal and cysteine-rich domains but lack the transmembrane and intracellular tyrosine kinase domains, indicating that the truncated forms are the secreted forms. The translation products of the truncated form mRNAs were detected in the stomach and kidney by Western analysis. However, the physiological significance of the secreted forms remains to be elucidated.

Alternative Splicing↗
PubMed1993

Nicotinic acetylcholine receptor mRNAs in myasthenic thymuses: association with intrathymic pathogenesis of myasthenia gravis.

Reverse transcription and the polymerase chain reaction showed that the alpha-, beta- and gamma-subunit genes of nicotinic acetylcholine receptor (AChR) in human skeletal muscle were expressed in myasthenia gravis (MG) thymuses (3 thymomas and 7 hyperplastic thymuses). A study of the expression of these subunit mRNAs in a variety of human tissues showed that alpha-subunit mRNA was expressed in human thymus and cerebral cortex, and that all three subunits were expressed only in human child thymus. Our results suggest that a complete AChR similar to extrajunctional (embryonic) muscle AChR is expressed in MG thymuses and that intrathymic AChR might be the primary antigen which induces autoimmune responses to muscle AChR.

Base Sequence↗
PubMed1993

Effect of bcl-2 on Fas antigen-mediated cell death.

Fas Ag is a cell surface protein that can mediate apoptosis and belongs to the TNF receptor family. The product of protooncogene bcl-2, a membrane-associated protein, has been shown to inhibit apoptosis in various hematopoietic cells including B cells and T cells. To examine the possible interaction of the Fas Ag and bcl-2, we coexpressed human Fas Ag and bcl-2 cDNA in murine IL-3-dependent FDC-P1 cell line and murine lymphoma WR19L. FDC-P1 transformants expressing bcl-2 showed a prolonged survival to IL-3 depletion. FDC-P1 transformants expressing the Fas Ag alone were killed by anti-Fas antibody in the presence of IL-3. Overexpression of bcl-2 in FDC-P1 resulted in a partial inhibition of Fas-induced cell death. WR19L transformants expressing bcl-2 were partially resistant to the cytolytic activities of the TNF-alpha and anti-Fas antibody treatment. These results suggest that the Fas Ag and TNF receptor may share the same signaling pathway, and that bcl-2 interferes with the apoptotic process mediated by the Fas Ag and TNF receptor.

Antigens, Surface↗
PubMed1993

A novel protein domain required for apoptosis. Mutational analysis of human Fas antigen.

The Fas antigen is a cell surface protein that can mediate apoptosis and that belongs to the tumor necrosis factor receptor family. Murine fibroblast L929 cells or T-cell lymphoma WR19L cells expressing the human Fas antigen were killed within 4-6 h by anti-human Fas antibody in a concentration-dependent manner. Human Fas antigen cDNAs with various mutations in the cytoplasmic region were constructed and expressed in L929 cells. A deletion of 15 amino acids from the C terminus of the Fas antigen enhanced the Fas antibody-induced killing activity, whereas a further deletion abolished its activity. This suggests the presence of an inhibitory as well as a signal-transducing domain in the cytoplasmic region of the Fas antigen. A 68-amino acid portion of the signal-transducing domain significantly conserved in the Fas antigen as well as in the type I tumor necrosis factor receptor was considered to be the novel protein domain required for apoptotic signal transduction.

Amino Acid Sequence↗
PubMed1993

Dup 753 prevents the development of puromycin aminonucleoside-induced nephrosis.

The appearance of nephrotic syndromes such as proteinuria, hypoalbuminemia, hypercholesterolemia and increase in blood nitrogen urea, induced in rats by injection of puromycin aminonucleoside was markedly inhibited by oral administration of Dup 753 (losartan), a novel angiotensin II receptor antagonist, at a dose of 1 or 2 mg/kg per day. The results suggest a possible involvement of the renin-angiotensin system in the development of puromycin aminonucleoside-induced nephrosis.

Angiotensin II↗
PubMed1993

The structure and expression of the FGF receptor-1 mRNA isoforms in rat tissues.

In this paper, we describe the structure of rat FGF receptor-1 mRNA isoforms and their expression in a variety of rat tissues. The rat FGFR-1 has the characteristics of FGFR-1 as well as mouse, human and chicken homologs. FGFR-1 mRNA was detectable in all the tissues examined by Northern analysis or polymerase chain reaction, indicating that FGFR-1 mRNA is widely expressed in rat tissues. The rat FGFR-1 mRNA has isoforms in both the extracellular and intracellular regions. The extracellular isoforms which have two or three immunoglobulin-like domains, are expressed almost equally in the tissues except for brain. However, the large form is a major form in the brain. Furthermore, in the brain, half of FGFR-1 mRNAs have the six nucleotides, which encode a potential serine-threonine kinase phosphorylation site in the intracellular juxta-membrane region, deleted. In contrast to the brain, the deletion isoform is a minor form in the other tissues. The tissue-specific expression of the isoforms indicates that they have different physiological functions. Although other isoforms of FGFR-1 mRNA in tumor cell lines have been reported, the isoforms were undetectable in all rat tissues examined, indicating the isoforms are products of abnormal alternative splicing in tumor cell lines.

Amino Acid Sequence↗
PubMed1993

Interleukin-6 as a mediator responsible for inflammation-induced increase in plasma angiotensinogen.

The concentration of plasma angiotensinogen increases upon induction of inflammation. Studies were carried out using serum samples collected from mice and rats after injection of lipopolysaccharide (LPS) to determine whether interleukin-6 (IL-6) is a mediator responsible for the inflammation-induced increase of angiotensinogen synthesis in liver cells. Serum collected from mice or rats 2 and 4 hr after injection of LPS contained a factor that stimulated [35S]methionine incorporation into angiotensinogen newly synthesized by rat hepatoma H4IIEC3 (H4) cells. Assay of IL-6 using an IL-6-dependent murine hybridoma, MH60.BSF2 cells, showed the presence of IL-6-like activity in sera of mice or rats 2 and 4 hr after injection of LPS. Anti-mouse IL-6 monoclonal antibody completely inhibited not only the IL-6-like activity present in LPS-treated mouse serum but also the ability of the serum to stimulate angiotensinogen synthesis of H4 cells. These results suggest that increased synthesis of angiotensinogen in the liver after induction of inflammation is mediated by IL-6, a cytokine important in immune reactions and the hepatic acute-phase response.

Angiotensinogen↗
PubMed1993

Motor neuron disease and past poliomyelitis. Geographic study in Hokkaido, the northern-most island of Japan. ALS Study Group.

We carried out a survey on the cases of motor neuron disease (MND) occurring in Hokkaido between 1980 and 1989 in order to establish whether there is a relationship between MND and poliomyelitis. Hokkaido, the northern-most island of Japan, was one of the most affected areas during the poliomyelitis epidemic of the late 1940s to 1950s. We ascertained 389 cases of MND for these 10 years and 2,171 cases of paralytic poliomyelitis for the period 1949-1958, and analysed their geographic distributions. No significant correlation was found between MND and poliomyelitis in their geographic distributions.

Adult↗
PubMed1993

Liver sarcoidosis showing low-density intrahepatic septa on postcontrast computed tomography.

The authors present a patient with massive liver sarcoidosis, showing only slight hepatomegaly on precontrast computed tomogram and multiple low-density intrahepatic septa on postcontrast computed tomogram. Sarcoidosis frequently involves the liver, but rarely shows abnormal findings other than hepatomegaly on computed tomograms. Only a few cases have demonstrated a low density intrahepatic area on computed tomograms. In this report, we present a patient with massive liver and pulmonary sarcoidosis, showing low density intrahepatic septa and pulmonary fibrosis on computed tomograms.

Humans↗
PubMed1993

Enhanced magnetic resonance imaging evaluation for spread of cervical carcinoma.

OBJECTIVES: Clinical diagnosis of cervical carcinoma fails to detect the location and extent of tumor invasion to cervical stroma and parametria. This study attempted to assess the accuracy of gadopentetate dimeglumine (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) in the evaluation for the extent of cervical carcinoma. METHODS: A total of 41 patients with primary untreated cervical carcinoma underwent MRI throughout the staging evaluations before surgical treatment. RESULTS: Without Gd-DPTA, T1-weighted images were less effective than T2-weighted images for MRI of pelvic organs. Gd-DTPA-enhanced T1-weighted images provided information similar to those of T2-weighted appearances, and distinguished the normal parametrium or vaginal wall from malignant invaded lesions more clearly. CONCLUSIONS: The enhancement with Gd-DTPA may increase the ability of MRI to provide a positive spread/metastasis staging.

Adult↗
PubMed1993

Serum enzyme activity evaluated in budgerigars (Melopsittacus undulatus) inflicted with muscle injury.

Aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK) and lactate dehydrogenase (LDH) concentrations were measured in 73 budgerigars. In spite of increases in the serum concentration of AST and ALT the loss of enzyme activity from the injection site occurred at about the same rate for all four enzymes tested. The rate constants, calculated in birds administered muscle extract via the intravenous or the intramuscular route of injection, disclosed that in subjects treated intramuscularly the serum enzyme elevation was dependent on the elimination half-life of the enzyme and partly on the rate at which the particular enzyme was absorbed into the bloodstream. Moreover, serum enzyme elevations correlated inversely with total clearance. To determine the aetiology of blood enzyme elevation in budgerigars, for diagnostic purposes, the absorption rate, total clearance and elimination half-life of each of these four enzymes are deemed valuable components.

Alanine Transaminase↗
PubMed1993

Anti-idiotypes against an anti-haloperidol antibody bind to sigma receptors.

Anti-idiotypic monoclonal antibodies that interact with the binding site of sigma receptors were generated. First, BALB/c mice were immunized with a haloperidol-bovine serum albumin conjugate, and monoclonal anti-haloperidol antibodies that recognize the piperidinyl moiety of haloperidol molecule were obtained. Second, for generation of anti-idiotypic antibodies, BALB/c mice were immunized with the anti-haloperidol monoclonal antibodies coupled to keyhole limpet hemocyanin. Anti-idiotypic antisera and three hybridomas secreting anti-idiotypic monoclonal antibodies were obtained. All of them were shown to inhibit [3H]haloperidol binding to the anti-haloperidol antibodies. The anti-idiotypes were potent in displacing the binding of [3H]haloperidol to rat brain sigma receptors. Furthermore, they significantly immunoprecipitated the sigma receptors from a detergent-solubilized preparation. These findings demonstrate the generation of anti-idiotypic monoclonal antibodies specifically interacting with membrane-bound and solubilized sigma receptors.

Animals↗
PubMed1993

Ultrasonically guided follicular aspiration during a pregnancy with massive ovarian cysts following ovulation induction by gonadotropins.

In this report, the treatment by follicular aspiration was evaluated in a pregnant patient with severe ovarian cysts subsequent to ovulation induction with CC and gonadotropins. The patient had dramatic and immediate improvement of the symptoms and general condition as well as a significant shorter hospital stay. The procedure was, under meticulous US guidance, safe and effective, providing additional improvement or increased therapeutic confidence in the severe complications after ovulation induction, as an assisted option during pregnancy.

Adult↗