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T Ishii

Publications and source records attributed to T Ishii.

At least 19 recordsLinked to original sources
PubMed1995

Inhibition of the thiol-specific antioxidant activity of rat liver MSP23 protein by hemin.

Mouse stress-inducible 23-kDa protein (MSP23) belongs to a new type of antioxidative protein family and is highly expressed in livers. To examine its physiological role in the tissue, we have purified native MSP23 protein from the cytosolic fraction of rat liver. The purified protein showed the thiol-specific antioxidant activity and protected glutamine synthetase from inactivation by a mixed metal-thiol oxidation. We examined the effect of hemin on that activity since it was recently shown by others that the rat liver MSP23 protein had a high binding affinity to heme. We have found that hemin at low concentrations inhibits the antioxidative activity of MSP23. This result suggests that one type of oxidant damage caused by hemin to cells is due to inactivation of the antioxidative protein, MSP23.

Ammonium Sulfate↗
PubMed1995

A novel 550-kDa protein in skeletal muscle of chick embryo: purification and localization.

We have found a novel protein with a molecular mass of 550 kDa on SDS-polyacrylamide gels, which is abundant in skeletal muscle tissues at an early stage of chick embryonic development. The 550-kDa protein decreased with the progress of development, and only a slight amount of the protein was present in adult chicken skeletal muscle. The 550-kDa protein was purified from the cytoplasm of 18 day embryos by a procedure including ultracentrifugation and gel filtration. The purified 550-kDa protein was essentially free of contaminants as judged by SDS-PAGE. By immunofluorescence and immunoelectron microscopy using the antibody raised against the 550-kDa protein, this protein was shown to be localized in the peripheries of adult muscle fibers and at the Z-disks of isolated myofibrils. These findings have led us to conclude that the 550-kDa protein is a novel myofibrillar protein in chicken skeletal muscle.

Animals↗
PubMed1995

Characterization of a novel 550-kDa protein in skeletal muscle of chick embryo.

Some characteristics of a novel 550-kDa protein which is abundant in skeletal muscle tissues at an early stage of the chick embryo, and localized in the peripheries of adult muscle fibers and at the Z-disks of isolated myofibrils, was investigated. A cosedimentation experiment and solid phase immunoabsorbent assay showed that the 550-kDa protein binds directly to F-actin. Therefore, it is concluded that the 550-kDa protein is a novel actin-binding protein. The 550-kDa protein was also interacted with alpha-actinin, laminin, fibronectin and Type IV collagen. Reactions with several kinds of lectin revealed that the 550-kDa protein is a glycoprotein containing oligosaccharides. Electron microscopic observation of negatively stained 550-kDa protein showed that native 550-kDa protein molecules are particles with an average diameter of 26.5 nm, but those particles treated with ethanol/ether are filamentous structures. These results suggest that the 550-kDa protein in the cytoplasma of unorganized skeletal muscle tissues exists as lipid-protein complex. Consequently, the 550-kDa protein may play an important role in the binding of myofibrils to the basal lamina by interaction with F-actin, alpha-actinin, laminin, fibronectin or Type IV collagen.

Actinin↗
PubMed1995

Constitutive overexpression of the L-selectin gene in fresh leukemic cells of adult T-cell leukemia that can be transactivated by human T-cell lymphotropic virus type 1 Tax.

L-selectin is an adhesion molecule of the selectin family that mediates the initial step of leukocyte adhesion to vascular endothelium. Upon cellular activation, expression of the L-selectin gene is downregulated at both the protein and mRNA levels. To understand the mechanism of leukemic cell infiltration into organs, we studied the expression and regulation of L-selectin mRNA in fresh leukemic cells of adult T-cell leukemia (ATL) patients and investigated the response of the L-selectin promoter to human T-cell lymphotropic virus type 1 (HTLV-1) Tax, which is a viral transcriptional transactivator. Flow cytometry showed that L-selectin was expressed on fresh ATL cells along with other activation antigens. Northern blot analysis showed that ATL cells overexpressed that L-selectin mRNA and that the level was aberrantly upregulated after PMA stimulation. Studies using in situ hybridization showed expression of the L-selectin mRNA in the infiltrating leukemic cells in the liver of two ATL patients. Intravenous injection of a rat T-cell line that overexpresses L-selectin showed increased organ infiltration. The induction of Tax expression in JPX9 cells resulted in about a twofold increase in the mRNA expression levels compared with the basal level. Chloramphenicol acetyltransferase (CAT) assay after transient cotransfection showed about a fivefold transactivation of the L-selectin promoter by Tax. The serum level of the shed form of L-selectin was significantly increased in ATL patients (mean +/- SD, 4,215.4 +/- 4,111 ng/mL) compared with those of asymptomatic carriers and healthy blood donors (mean +/- SD, 1,148.0 +/- 269.0 ng/mL and 991.9 +/- 224 ng/mL, respectively). These results indicated that ATL cells constitutively overexpress the L-selectin gene that can be transactivated by HTLV-1 Tax. The overexpression of L-selectin, as well as of inflammatory cytokines, by ATL cells may provide a basis for ATL cells to attach the vascular endothelium, leading to transmigration and organ infitration.

Adult↗
PubMed1995

Release of biological activities from quiescent fibronectin by a conformational change and limited proteolysis by matrix metalloproteinases.

We reported that specific biological activities are confined to three domains of the fibronectin (Fn) molecule [Fukai et al. (1991) J. Biol. Chem. 266, 8807; Fukai et al. (1993) Biochemistry 32, 5746]: the potent ability to stimulate the adipocyte differentiation of ST-13 cells is in the amino-terminal fibrin-binding (Fib 1) domain (referred to as Fib 1 domain activity); the RGD-dependent activities that stimulate NIH-L13 cell migration and inhibit adipocyte differentiation are in the central cell-binding (Cell) domain (Cell domain activity); and the activity that stimulates cell migration in a RGD-independent manner is in the carboxyl-terminal fibrin-binding (Fib 2) domain (Fib 2 domain activity). Human plasma Fn which was purified without exposure to a denaturant, such as urea, exhibited no Fib 1, Fib 2, or Cell domain activity. By exposure to urea or surface adsorption, Fn showed Cell domain activity but not those of the Fib 1 and Fib 2 domains. Whether the cryptic domain activities are disclosed or not depended on whether or not the responsible domains were irreversibly exposed from confined environments of Fn structure as confirmed by light-scattering measurement and enzyme immunoassay using domain-specific monoclonal antibodies. We then investigated the action of matrix metalloproteinases (MMPs) in liberating the Fib 1, Cell, and Fib 2 domain activities. Matrilysin released only the Cell domain activity. In contrast, stromelysin, collagenase, and especially gelatinase A additionally liberated the Fib 1 and Fib 2 domain activities. The Fib 1, Fib 2, and Cell domains acquired much higher activities when they were freed from linkage with adjacent domains.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1995

Fibrous hamartoma of the tongue: report of a case with immunohistochemical and ultrastructural studies.

The case of an 8-month-old female with fibrous hamartoma of the tongue is reported with immunohistochemical and electron microscopic findings. An elastic hard mass at the base of the tongue gradually enlarged, causing dysphagia. The tumor was excised by CO2 laser. Under light microscopy, the tumor was observed as composed of fibroblast-like cells, fibrocollagenous bundles and striated muscle tissues. The majority of the cells were immunoreactive for vimentin. Electronmicroscopically, they contained numerous intermediate filaments, some had intercellular microvilli and cilia (9 + 2 type). These findings revealed that the cells of the fibrous hamartoma in our case may possess both mesenchymal and epithelial properties.

Female↗
PubMed1995

A new cis-acting element for RNA replication within the 5' noncoding region of poliovirus type 1 RNA.

Mouse cells expressing the human poliovirus receptor (PVR-mouse cells) as well as human HeLa cells are susceptible to poliovirus type 1 Mahoney strains and produce a large amount of progeny virus at 37 degrees C. However, the virus yield is markedly reduced at 40 degrees C in PVR-mouse cells but not in HeLa cells. The reduction in virus yield at 40 degrees C appears to be due to a defective initiation process in positive-strand RNA synthesis (K. Shiroki, H. Kato, S. Koike, T. Odaka, and A. Nomoto, J. Virol. 67:3989-3996, 1993). To gain insight into the molecular mechanisms involved in this detective process, naturally occurring heat-resistant (Hr)-mutants which show normal growth ability in PVR-mouse cells even at 40 degrees C were isolated from a virus stock of the Mahoney strain and their mutation sites that affect the phenotype were identified. The key mutation was a change from adenine (A) to guanine (G) at nucleotide position (nt) 133 within the 5' noncoding region of the RNA. This mutation also gave an Hr phenotype to the viral plus-strand RNA synthesis in PVR-mouse cells. Mutant Mahoney strains with a single point mutation at nt 133 (A to G, C, or T or deletion) were investigated for their ability to grow in PVR-mouse cells at 40 degrees C. Only the mutant carrying G at nt 133 showed an Hr growth phenotype in PVR-mouse cells. These results suggest that a host cellular factor(s) interacts with an RNA segment around nt 133 of the plus-strand RNA or the corresponding region of the minus-strand RNA, contributing to efficiency of plus-strand RNA synthesis.

Animals↗
PubMed1995

Most thymocytes die in the absence of DNA fragmentation.

Most thymocytes are known to be depleted from the thymus during T cell development, with the process of thymocyte death considered to be apoptosis. In this study we examined the mechanism of thymocyte death in the thymus of 6-week-old mice by using terminal deoxynucleotidyl transferase to detect DNA fragmentation or double strand breaks (TUNEL method). The TUNEL positive thymocytes were scattered throughout the cortex. Double staining of the section with the TUNEL method and acid phosphatase (ACP) activity showed that all the TUNEL positive cells were phagocytosed by ACP positive macrophages. An ultra-structural study revealed the presence of a substantial number of extremely small, unphagocytosed thymocytes throughout the cortex. These small unphagocytosed thymocytes were apparently dead cells, as based on several morphological features: 1) The majority were much smaller than red blood cells; 2) the nuclei were also considerably small; and 3) the extent of chromatin condensation was enormous. Importantly, these unphagocytosed dead thymocytes were TUNEL negative. These results indicate that: 1) DNA fragmentation, which is detected by the TUNEL method, is not involved in the cell death process of small unphagocytosed dead thymocytes shown in the present study; and that 2) typical apoptosis, which is characterized by DNA fragmentation, is not the dominant type of cell death in the normal murine thymus. Processes of cell death other than typical apoptosis taking place in most thymocytes require further investigation.

Animals↗
PubMed1995

TAN-1323 C and D, new concanamycin-group antibiotics; detection of the angiostatic activity with a wide range of macrolide antibiotics.

We detected potent angiostatic activity in a MeOH extract from the mycelia of microbial strain S-45628 in the chick chorioallantoic membrane (CAM) assay. The producer was taxonomically characterized as Streptomyces purpurascens. Active principles designated TAN-1323 A-D were isolated and determined to be 18-membered macrolide antibiotics; components C and D are new members of this group, while components A and B are identical to concanamycins C and A, respectively. When tested in the CAM assay, components B and D gave huge avascular zones at the extremely low doses of 10-100 ng/disk, although components A and C showed far weaker activity due to their preferential tissue-damaging effect on the CAM. The discovery that these 18-membered macrolide antibiotics are angiostatic substances prompted us to examine other types of macrolide antibiotics, leading to the discovery that 16-membered macrolide antibiotics such as bafilomycin C1, tylosin and leucomycin also show angiostatic activity on the CAM. Thus, angiostatic potential is widely distributed among macrolide antibiotics. The mechanism of action of these macrolide antibiotics is also discussed.

3T3 Cells↗
PubMed1995

[Neurilemmoma of intra-temporal facial nerve:case report].

A case of facial nerve neurilemmoma within the temporal bone is reported. The patient is a 47-year-old female complaining of 10 years' history of left facial palsy. CT and MRI examinations showed an enlarged mass of the tympanic cavity protruding into the petrous bone, mastoid cavity and external auditory meatus. An open biopsy of the tumor at the external auditory meatus revealed neurilemmoma. The tumor was totally removed by a retroauricular approach. Five months after surgery, both the cross nerve graft using the peroneal nerve and the temporal muscle transfer, method modified by Johnson were performed for the functional recovery of facial palsy.

Cranial Nerve Neoplasms↗
PubMed1995

Evidence for the presence of an inactive precursor of human hepatocyte growth factor in plasma and sera of patients with liver diseases.

Human hepatocyte growth factor (hHGF), which is now known to be the same protein as the scatter factor and the tumor cytotoxic factor, is a heterodimeric protein with one heavy chain and one light chain linked together by a disulfide bond, and is thought to be involved in liver regeneration. Using an enzyme-linked immunosorbent assay (ELISA) and Western blot analysis, we found that a significant amount of single chain precursor of hHGF (pro-hHGF) was present in plasma of patients with fulminant hepatic failure (FHF) and that normal human serum contained a protease or proteases that convert pro-HGF to a heterodimeric (mature) form of hHGF. We also showed that the processing protease activity for hHGF was suppressed by such serine protease inhibitors as leupeptin, antipain, and aprotinin, and that sera of patients with liver diseases such as fulminant hepatic failure, acute hepatitis, chronic hepatitis, and cirrhosis contained not only pro-hHGF but also the protease. This is the first report showing the presence of pro-hHGF in human blood, and our observations suggest that hHGF is synthesized and secreted from the hHGF-producing cells as an inactive pro-hHGF after hepatic injuries, and the pro-hHGF is then converted to an active heterodimeric form of hHGF in the blood. It is also suggested that plasma of patients with liver diseases contains an active protease or proteases that convert pro-hHGF to a mature form of hHGF.

Animals↗
PubMed1995

Necessity of newly synthesized ATP by creatine kinase for contraction of permeabilized longitudinal muscle preparations of rat proximal colon.

Necessity of newly synthesized ATP by creatine kinase for synthesis of ATP as an energy source for smooth muscle contraction was studied in permeabilized longitudinal muscle preparations of rat proximal colon. In alpha-toxin-permeabilized preparations, Ca++ induced "phasic type" contraction in a normal bath solution containing 4 mM ATP and 5 mM phosphocreatine. Omission of phosphocreatine from the solution resulted in significant decrease in phasic contraction, and omission of ATP resulted in loss of the response to Ca++. When ADP, but not adenosine-5-O-(2-thiodiphosphate), with phosphocreatine was added as a substitute for ATP, Ca++ induced the same type of contraction as with ATP. The maximum tensions of the phasic and tonic phases of the contraction with ADP were approximately 60% of, and almost the same, respectively as those with ATP. A selective inhibitor of creatine kinase, 2,4-dinitrofluorobenzene, inhibited the phasic contraction induced by Ca++. After irreversible inhibition of endogenous creatine kinase by DNFB in beta-escin-permeabilized preparations, treatment of the preparations with exogenous creatine kinase restored Ca(++)-induced contraction. These findings suggest that ATP synthesized from ADP and phosphocreatine by creatine kinase was necessary for phasic contraction of permeabilized smooth muscle and that exogenous ATP was mainly used after its hydrolysis to ADP.

Adenosine Diphosphate↗
PubMed1995

[Clinical study on cerebrovascular diseases after renal transplantation].

Between October 1975 and December 1994, 131 renal transplants were performed on our hospital. Eight of these patients had 9 cerebrovascular diseases, which were 2 cerebral hemorrhages, 5 cerebral infarctions, 2 subarachnoid hemorrhages. Five of the 8 patients whose graft functions were bad died. We studied the relationship of the incidence of these complications to some factors as follows; 1) blood pressure, 2) hypercholestemia, 3) duration of hemodialysis, and 4) graft function. The cerebrovascular diseases after renal transplantation were related to the hypertension after renal transplantation and no correlation with the other factors could be found. Therefore, we think that the control of the hypertension after renal transplantation is the most important for the cerebrovascular diseases and the patient's prognosis.

Adult↗
PubMed1994

Elastase gene expression in non-elastase-producing Pseudomonas aeruginosa strains using novel shuttle vector systems.

In order to determine whether non-elastase-producing strains of Pseudomonas aeruginosa such as N-10, PA103 and IFO3080 can express foreign elastase genes, we introduced elastase genes from P. aeruginosa IFO3455 (elastase-producing) as well as from PA103 and N-10 into non-elastase-producing P. aeruginosa strains. Results suggested that gene expression, secretion, and precursor processing systems of elastase were essentially normal in P. aeruginosa N-10 and IFO3080. Our studies using various elastase genes showed that both the elastase structural gene and 5'-upstream regions of P. aeruginosa PA103 were also normal. This was confirmed by the finding that P. aeruginosa N-10 and IFO3080 which carry the PA103 elastase gene produced elastase. Several deleted or chimeric genes were constructed using the 5'-upstream regions of elastase genes from P. aeruginosa N-10 or PA103 and studies of expression revealed that two individual DNA bases seem to be important in suppressing P. aeruginosa N-10 elastase gene expression. Possible reasons for the lack of elastase expression in these non-elastase-producing strains are discussed.

Base Sequence↗
PubMed1994

Hepatitis B surface antigen, hepatitis C virus antibody, body mass index, and alcohol drinking among workers with elevated serum alanine aminotransferase.

METHODS: We conducted a case-control study on liver diseases among Japanese workers to examine associations between elevated serum alanine aminotransferase (alanine aminotransferase value > or = 50 IU/liter) and selected factors such as hepatitis B surface antigen positive, hepatitis C virus antibody positive, body mass index, and alcohol drinking. Out of 3,738 workers (1,477 males and 2,261 females) in a supermarket chain, 91 workers with an elevated serum alanine aminotransferase value (> or = 50 IU/liter) were classified as cases and 182 workers with normal serum alanine aminotransferase value and without an episode of blood transfusion were randomly selected as controls. RESULTS: Prevalence rates of hepatitis B surface antigen positive and hepatitis C virus antibody positive were 4.4 and 23.1% among the overall cases, 2.9 and 11.8% among the cases with 100 > alanine aminotransferase value > or = 50, and 8.7 and 56.5% among the cases with alanine aminotransferase value > or = 100. A logistic regression analysis was conducted. Odds ratios were 4.94 for hepatitis B surface antigen positive (P < 0.05) and 77.19 for hepatitis C virus antibody positive (P < 0.001). Odds ratios for body mass index increased with increasing body mass index values; 3.32 for 26 > body mass index > or = 24 (P < 0.01) and 5.03 for body mass index > or = 26 (P < 0.001). No increased risk was observed among regular drinkers of less than 27 g/day of ethanol (odds ratio is 0.23) or of 27-53 g/day of ethanol (odds ratio is 0.47). A slightly increased odds ratio of 1.35 was observed among regular drinkers of 54-81 g/day of ethanol, but this was not statistically significant. CONCLUSIONS: Our results suggest that hepatitis C virus and high body mass index are predominant factors in elevated serum alanine aminotransferase levels among Japanese workers, while alcohol drinking is a minor factor.

Adult↗
PubMed1994

Evidence that FK506 alleviates ischemia/reperfusion injury to the rat liver: in vivo demonstration for suppression of TNF-a production in response to endotoxemia.

The mechanism by which FK506 (FK) prevents hepatic injury induced by ischemia/reperfusion was studied. Adult Sprague-Dawley rats were subjected to 60-min normothermic liver ischemia. Animals were divided into two groups: group I, controls, saline vehicle treatment; group II, FK treatment. FK (1 mg/kg/day, p.o.) was given for 4 consecutive days prior to inducing ischemia. In addition to a survival study, plasma levels of endotoxin and serum activities of tumor necrosis factor-alpha (TNF) and aspartate aminotransferase (AST) were assessed in the blood collected from suprahepatic vena cava. Results showed: (1) FK therapy significantly improved 7-day survival (80.0%) compared with nontreated animals (50.0%, p < 0.05); (2) both TNF and endotoxin were elevated following reperfusion, reaching maximum values at 3 h after reperfusion (217.0 +/- 40.6 and 280.5 +/- 31.4 pg/ml, respectively, in the control; mean +/- SEM), and (3) serum activities of TNF and AST following reperfusion were substantially suppressed with FK treatment, whereas FK did not reduce the rise in endotoxin. These findings suggest that suppression of TNF production in response to endotoxemia might account at least in part for the protective effect of FK against ischemia-induced hepatic injury.

Animals↗