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T Kawabe

Publications and source records attributed to T Kawabe.

At least 91 records · Page 5Linked to original sources
PubMed1998

Effect of gene transfer of tumor necrosis factor receptors into human lung carcinoma cell line.

The human lung adenocarcinoma cell line A549 is known to be resistant to tumor necrosis factor alpha (TNF-alpha)-mediated tumor cell lysis in spite of the expression of 55 kDa TNF receptor (TNF-R55) mRNA and its cell surface protein. In this study, we investigated the mechanism of TNF-alpha resistance and the role of two types of TNF receptors (TNF-R55 and TNF-R75 (75 kDa TNF receptor)). TNF-R55 or TNF-R75 cDNA was transfected into A549 cells. In addition, a C-terminal deletion mutant of TNF-R75 which lacks the intracellular domain of TNF-R75 was also transfected into A549 cells. We assessed the TNF-alpha-mediated tumor cell lysis of these transfected clones, and found that the cytotoxic effect increased in transfected clones highly expressing TNF- R55, but not in low-expression clones. As for TNF-R75, the cytotoxic effect of TNF-alpha was observed in TNF-R75-transfected clones even when expression was low. Furthermore, the cytotoxic effect was also observed in clones transfected with the deletion mutant of TNF-R75, as well as the complete TNF-R75. These results indicate that a certain level of expression of TNF-R75 is necessary for obtaining TNF-alpha-mediated tumor cell lysis in the absence of TNF-R75. On the other hand, the expression of TNF-R75 strongly induces TNF-alpha-mediated cytotoxicity through TNF-R55 in the absence of an intracellular signal via TNF-R75.

Adenocarcinoma↗
PubMed1998

Successful polymerase chain reaction-based diagnosis of fungal meningitis in a patient with chronic granulomatous disease.

Meningitis is not a common complication of chronic granulomatous disease (CGD). Here, we present details of a 3-year-old boy with X-linked CGD, who suffered from fungal meningitis. While 19 samplings using conventional cerebrospinal fluid (CSF) cultures failed to detect any organisms, fungal DNA was identified in the CSF by a new polymerase chain reaction (PCR)-based method. The patient recovered without any sequelae after treatment with a combination of antifungal agents, interferon-gamma and granulocyte infusions. This case report demonstrates that fungal meningitis must be included in the differential diagnosis of infections in CGD patients and that the PCR-based detection of fungal DNA is a powerful tool for diagnosis.

Child, Preschool↗
PubMed1998

Bystander tumoricidal effect and gap junctional communication in lung cancer cell lines.

Tumor cells expressing the herpes simplex virus-thymidine kinase (HSV-tk) gene become sensitive to ganciclovir (GCV), and the phenomenon by which tumor cells surrounding the HSV-tk expressing cells also become sensitive to GCV is known as the "bystander effect." The purpose of this study was to investigate the bystander effect in human lung-cancer cell lines, and the role of gap-junctional intercellular communication as the mechanism responsible for it. Gap-junctional intercellular communication was measured both with a dye-transfer assay involving single-cell microinjection of Lucifer Yellow and with a PKH26/calcein-AM double-dye-transfer assay. Significant bystander tumoricidal effect was observed in lung-cancer cell lines when cultured cells contained only 10% HSV-tk expressing cells. This was also observed to occur with cell lines of different origin or from different species. Although gap-junctional intercellular communication characterized by rapid transfer of Lucifer Yellow was not observed, we did detect gap-junctional communication marked by the slow transfer of calcein-AM in lung-cancer cell lines. However, neither an inhibitor (1-octanol) nor an enhancer (all trans-retinoic acid [ATRA]) of gap-junctional communication affected the extent of the bystander effect. These findings suggest that low levels of gap-junctional communication may be efficient for producing the bystander effect in lung-cancer cells, or that other mechanisms may underlie this effect. Although gap-junctional communication may play an important role in generating the bystander effect in tumor cells expressing the HSV-tk gene, further knowledge of the mechanism of this effect may help improve the treatment of lung cancer with an HSV-tk system.

1-Octanol↗
PubMed1997

A canalicular multispecific organic anion transporter (cMOAT) antisense cDNA enhances drug sensitivity in human hepatic cancer cells.

The human cMOAT gene encodes a membrane protein involved in the ATP-dependent transport of hydrophobic compounds. To determine whether cMOAT is associated with drug sensitivity, we transfected an expression vector containing cMOAT antisense cDNA into the HepG2 human hepatic cancer cell line. We observed a reduction in cMOAT protein, as well as an enhanced level of glutathione, in the antisense transfectants. The transfectants displayed an increased sensitivity to cisplatin, vincristine, doxorubicin, and the camptothecin derivatives, (4S)-4,11-diethyl-4-hydroxy-9-[(4-piperidinopiperidino)carbonyl oxy]dione hydrochloride triethydrate and 7-ethyl-10-hydroxycamptothecin, but not to etoposide, 3-[4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitrosoure a, 5-fluorouracil, and mitomycin C. Results suggest that cMOAT levels are inversely correlated with those of glutathione, and that cMOAT and its related genes may be involved in the sensitivity of cells to certain anticancer agents.

ATP-Binding Cassette Transporters↗
PubMed1997

Expression of vascular endothelial growth factor at the human gastric ulcer margin and in cultured gastric fibroblasts: a new angiogenic factor for gastric ulcer healing.

Angiogenesis plays a pivotal role in gastric ulcer repair. Several growth factors are involved in angiogenesis, and of these, vascular endothelial growth factor (VEGF) has received considerable attention, since it is the only factor that specifically acts on endothelial cells. However, the role of VEGF in gastric ulcer repair is not known. In the present study, we demonstrate the specific expression of VEGF at the gastric ulcer margin, using immunohistochemistry and RT-PCR. The specific receptors of VEGF, flt-1 and KDR were also detected in gastric mucosa. We further demonstrate the expression of VEGF by cultured human gastric fibroblasts which is enhanced by tumor necrosis factor-alpha. These data suggest that VEGF may play a role in angiogenesis in the process of gastric ulcer healing.

Base Sequence↗
PubMed1997

Antioxidant defenses of cultured colonic epithelial cells against reactive oxygen metabolites.

Reactive oxygen metabolites produce colonic epithelial cellular injury. The present study evaluated the protective role of cellular superoxide dismutase, catalase, and glutathione (GSH) redox cycle in cultured rabbit colonic cells. Cultured rabbit colonic epithelial cells were exposed to reactive oxygen metabolites generated by hypoxanthine (1 mM) and xanthine oxidase (1 mU/ml) for up to 5 h. Cytotoxicity was quantified by measuring 51Cr release from prelabeled cells. Pretreatment with diethyldithiocarbamate (inhibitor of superoxide dismutase) reduced activity of cellular superoxide dismutase and increased 51Cr release caused by hypoxanthine/xanthine oxidase from colonic cells. Pretreatment with diethyl maleate (covalently binds GSH as catalyzed by GSH transferase), or buthionine sulfoximine (inhibitor of gamma-glutamylcysteine synthetase) decreased cellular GSH and enhanced reactive oxygen metabolites induced injury. Pretreatment with bis(chloroethyl)-nitrosourea (inhibitor of GSH reductase) inhibited activity of GSH reductase and increased 51Cr release from colonic cells. Preincubation with aminotriazole (inhibitor of catalase) reduced cellular catalase, but did not affect cellular injury. Therefore, we concluded that both cellular superoxide dismutase and the GSH redox cycle appeared to play a role in detoxifying reactive oxygen metabolites and that cellular catalase may be less important in rabbit colonic epithelial cells.

Animals↗
PubMed1997

HOX11 interacts with protein phosphatases PP2A and PP1 and disrupts a G2/M cell-cycle checkpoint.

Hox11 is an orphan homeobox gene that controls the genesis of the spleen. HOX11 is also oncogenic, having been isolated from a chromosomal breakpoint in human T-cell leukaemia. Transgenic mice that redirected HOX11 to the thymus demonstrated cell-cycle aberration and progression to malignancy. We observed that the protein HOX11 interacted with protein serine-threonine phosphatase 2A catalytic subunit (PP2AC), as well as protein phosphatase 1 (PP1C) in mammalian cells. Inhibition of PP2A can regulate the cell cycle and control the activation of maturation-promoting factor in Xenopus oocytes. Microinjection of HOX11 into Xenopus oocytes arrested at the G2 phase of the cell cycle promoted progression to the M phase. G2 arrest can be induced by gamma-irradiation, but is eliminated by expression of HOX11 within a T-cell line. Thus HOX11 is a cellular oncogene that targets PP2A and PP1, both of which are targets for oncogenic viruses and chemical tumour promoters. This interaction suggests a mechanism by which a homeobox can alter the cell cycle.

Animals↗
PubMed1997

Hydrogen peroxide-mediated cytotoxicity to cultured colonic epithelial cells.

Reactive oxygen metabolites (ROM) contribute to colonic cellular injury, in certain pathophysiological conditions. We investigated the role of iron and individual metabolites in their cytotoxicity to cultured colonic epithelial cells from adult white rabbits. Reactive oxygen metabolites, enzymatically generated by hypoxanthine/xanthine oxidase, have a direct cytotoxic effect on cultured colonic epithelial cells. This cellular injury was inhibited by catalase but not SOD. Damage was not aggravated by ferrous iron or EDTA-chelated iron. Such damage was prevented by chelating intracellular iron, but not extracellular iron. These results suggest that H2O2 is more toxic to colonic epithelial cells than 02.- and OH. in the extracellular space. H2O2 enter the intracellular space and is converted to the more reactive and harmful OH. leading to cellular injury in the presence of intracellular iron.

Animals↗
PubMed1997

Platelet-derived growth factor prevents ischemia-induced neuronal injuries in vivo.

Platelet-derived growth factor (PDGF) has been considered to be a neuroprotective factor candidate on the basis of several in vitro studies. However, the in vivo effect of PDGF on ischemic neurons has not been determined. In the present study, the effect of PDGF-BB on the ischemia-induced disability of passive avoidance task and hippocampal CA1 neuron death in normothermic gerbils, whose the brain temperature was kept at 37.0 +/- 0.2 degrees C during 3-min occlusion of the common carotid arteries was investigated. When PDGF-BB was continuously infused for 7 days into the cerebral ventricles of gerbils with transient forebrain ischemia, response latency time in a passive avoidance task was significantly prolonged. Subsequent histological examinations showed that PDGF-BB effectively increased the number of viable pyramidal neurons in the hippocampal CA1 region as well as synapses within the strata moleculare, radiatum and oriens of the region in comparison with the numbers of neurons and synapses in vehicle-treated ischemic gerbils. In situ detection of DNA fragmentation (TUNEL staining) revealed that TUNEL-positive neurons in the hippocampal CA1 field of vehicle-treated ischemic gerbils were much more numerous than those in the field of PDGF-BB-treated ischemic animals after 7 days ischemia. These findings suggest that the present ischemic animal model exhibits a more delayed neuronal degeneration of the hippocampal CA1 field than the conventional 5-min ischemic model and that the 7-day infusion of PDGF-BB, starting 2 h before ischemic insult, not only prevents delayed neuronal death in the hippocampal CA1 field at 7 days after forebrain ischemia but also inhibits a slowly progressive neuronal degeneration occurring thereafter.

Animals↗
PubMed1997

High seropositivity of anti-CagA antibody in Helicobacter pylori-infected patients irrelevant to peptic ulcers and normal mucosa in Japan.

CagA-positive H. pylori is reported to be associated with gastroduodenal disease in Western countries. To evaluate the relationship between CagA and disease, cloning of the entire cagA gene (3771 bp), insertion of a partial fragment (1272 bp) into an expression vector, purification of the recombinant protein, production of an antibody against the recombinant CagA protein through rabbits, and use of the recombinant CagA protein as an antigen, detection of the anti-CagA antibody by western blotting were all performed. Sera of 132 H. pylori-infected patients undergoing endoscopy were studied. Anti-CagA antibodies were detected in 90%, 87%, 90%, 94%, and 93% of patients with gastric ulcer (N = 34), duodenal ulcer (N = 27), chronic gastritis (N = 31), gastric cancer (N = 17), and normal mucosa (N = 15), respectively. High seropositivity of anti-CagA antibody even in individuals with normal mucosa indicated that CagA may not be a unique marker for disease by H. pylori infection in Japan.

Amino Acid Sequence↗
PubMed1997

High prevalence of cytotoxin positive Helicobacter pylori in patients unrelated to the presence of peptic ulcers in Japan.

BACKGROUND: It has been reported that infection with vacuolating cytotoxin positive Helicobacter pylori strains is associated with gastroduodenal disease in Western countries. AIMS: To evaluate the prevalence of cytotoxin producing strains among patients with H pylori infection in relation to gastrointestinal diseases in Japan. PATIENTS: Ninety seven patients undergoing endoscopy. METHODS: A Western blot assay was conducted to detect serum antibodies against the cytotoxin using recombinant cytotoxin (VacA protein) as an antigen. To obtain a purified recombinant cytotoxin, the vacA gene (2233 nucleotides) was cloned into an expression vector to produce the protein (744 amino acids), which was expressed in Escherichia coli. RESULTS: Serum IgG antibodies to the cytotoxin were present in 85%, 95%, 95%, and 100% of infected patients with gastric ulcer (n = 26), duodenal ulcer (n = 21), chronic gastritis (n = 19), and endoscopically normal mucosa (n = 14), respectively. CONCLUSION: The western blot method using recombinant VacA protein is simple and useful for detecting antibody to vacuolating cytotoxin. This method showed antibodies against cytotoxin were highly prevalent, even in subjects with endoscopically normal mucosa in Japan, indicating that the cytotoxin may not be an independent cause of gastrointestinal diseases induced by H pylori infection.

Amino Acid Sequence↗
PubMed1997

Importance of microperineural invasion as a prognostic factor in ampullary carcinoma.

BACKGROUND: This was a study of the relation of clinicopathological factors to prognosis in 25 patients who had ampullary carcinoma resected. METHODS: The 5-year survival rate was six of the 25 patients. The presence of microperineural invasion was sought and related to outcome. RESULTS: Factors relating to prognosis included tumour gross appearance, diameter, pancreatic invasion and microperineural invasion. The 5-year survival rate of 14 patients with microperineural invasion was 3, significantly worse than the 7 in 11 without invasion (P = 0.002, univariate analysis). By multivariate analysis, microperineural invasion was the most important prognostic factor (P = 0.02). Type of tumour recurrence was similar to that in pancreatic carcinoma. CONCLUSION: Pancreaticoduodenectomy, rather than local resection, is the procedure of choice in patients with ampullary carcinoma.

Aged↗
PubMed1997

A new simple assay for determining aminoglycoside inactivation in intact cells of Pseudomonas aeruginosa.

Intact cells of aminoglycoside (AG) antibiotic-resistant Pseudomonas aeruginosa usually do not inactivate AG, even though they possess the AG-modifying enzyme. An assay method for determining the activity of inactivating enzyme in intact cells of streptomycin-resistant P. aeruginosa was previously reported. Although this assay method was applied to the determination of the activity of kanamycin (KM)-inactivating enzymes, it could not apply to some of the KM-resistant strains. A new simple assay method has now been investigated for determining the activity of KM-inactivating enzyme in intact cells of clinically isolated KM-resistant P. aeruginosa. The determination of AG-inactivating enzyme activity was attempted using lysozyme for release of the inactivating enzymes in washed cells, and both DNase and RNase were added to digestion of the nucleic acids released by bacteriolysis. This lysozyme-DNase-RNase (LDR) method has facilitated the confirmation of the presence of AG-inactivating enzyme in the strains used. In addition, the LDR technique was applicable to the determination of inactivating enzyme activity for various AGs other than KM. Since this simple assay method can determine any type of AG-inactivating enzyme activity of various P. aeruginosa strains, it may contribute significantly to the rapid selection of drugs in clinical use.

Anti-Bacterial Agents↗
PubMed1996

A human canalicular multispecific organic anion transporter (cMOAT) gene is overexpressed in cisplatin-resistant human cancer cell lines with decreased drug accumulation.

By targeting the ATP binding conserved domain in three ATP binding cassette superfamily proteins (P-glycoprotein, multidrug resistance protein, and cystic fibrosis transmembrane regulator), we isolated the cDNA of a new ATP binding cassette superfamily that was specifically enhanced in a cisplatin-resistant human head and neck cancer KB cell line. A human clone homologous to rat canalicular multispecific organic anion transporter (cMOAT) was found and designated human cMOAT. Fluorescence in situ hybridization demonstrated the chromosomal locus of the gene on chromosome 10q24. The human cMOAT cDNA hybridized a 6.5-kb mRNA that was expressed 4- to 6-fold higher by three cisplatin-resistant cell lines derived from various human tumors exhibiting decreased drug accumulation. Human cMOAT may function as a cellular cisplatin transporter.

Adenosine Triphosphate↗