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T Kawabe

Publications and source records attributed to T Kawabe.

At least 37 records · Page 2Linked to original sources

Sepsis increases NOS-2 activity and decreases non-NOS-mediated acetylcholine-induced dilation in rat aorta.

INTRODUCTION: Acetylcholine (Ach) is frequently used to assess endothelium-dependent vasodilation during sepsis. However, the effects of sepsis on constitutive nitric oxide synthase activity (NOS-1 and -3) and other non-NOS effects of Ach are unclear. METHODS: Sepsis was induced in rats by inoculation of an implanted sponge with Escherichia coli and Bacteroides fragilis (10(9) CFU each). Thoracic aortic rings (2 mm) were harvested at 24 h from septic (N = 9) and control (N = 9) rats and were suspended in physiological salt solution (PSS), PSS + l-N(6)-(1-iminoethyl)lysine (l-NIL: NOS-2 inhibitor, 10 microM), or PSS + l-N(G)-monomethylarginine (l-NMMA: NOS-1, -2, and -3 inhibitor, 60 microM). Rings were set at 1-g preload and precontracted with phenlyephrine (10(-8) M). Relaxation dose-response curves were generated with six doses of Ach (3 x 10(-8) to 10(-5) M). RESULTS: Sepsis increased the maximal relaxation to Ach under basal conditions. NOS 2 inhibition with l-NIL decreased Ach-induced relaxation in controls (66% vs 84%, P < 0.05, two-way ANOVA) and more so in septic rats (44% vs 93%, P < 0.05). Total NOS inhibition with l-NMMA decreased Ach-induced relaxation to 45% (P < 0.05) in controls and to 30% (P < 0.05) in septic animals. CONCLUSIONS: Inhibition of NOS-1, -2, and -3 failed to abolish Ach-induced relaxation, suggesting the presence of other Ach-induced vasodilator mechanisms. NOS-2 inhibition reduced Ach-induced relaxation by 20-25% in the normal thoracic aorta, but by 50% in septic animals. The remaining Ach-induced non-NOS vasodilation (after inhibition of NOS-1 + NOS-2 + NOS-3) was reduced from 45% in normals to 30% in septic animals. Vascular dysregulation in sepsis is a complex event involving increased NOS-2, decreased NOS-1 + NOS-3, and decreased Ach-induced non-NOS vasodilator mechanisms.

Acetylcholine↗

Clonal chromosomal aberrations accompanied by strong telomerase activity in immortalization of human B-lymphoblastoid cell lines transformed by Epstein-Barr virus.

Human B-lymphoblastoid cell lines transformed by Epstein-Barr (EBV-LCLs) are considered to be immortalized, although most of them show a normal diploid karyotype. Recently, we and others have shown that only part of EBV-LCLs is immortalized by developing strong telomerase activity that stabilizes the telomeres. In this study, we investigated the change in karyotypes during immortalization. All the eight immortalized cell lines developed clonal chromosomal aberrations accompanied by the development of strong telomerase activity. Interestingly, abnormal chromosomes were not shared among the immortalized cell lines. These results strongly suggest that chromosomal rearrangements and induction of strong telomerase activity are two events that take place in parallel in the process of immortalization of EBV-LCLs, and indicate that EBV-LCLs are clearly divided into two distinct groups, pre-immortal cell lines mostly with a normal diploid karyotype and post-immortal cell lines with a clonally abnormal karyotype.

B-Lymphocytes↗

Expression of human brain carboxypeptidase B, a possible cleaving enzyme for beta-amyloid precursor protein, in peripheral fluids.

Human brain carboxypeptidase B (HBCPB) is a novel brain protease that processes native brain beta-amyloid precursor protein (APP) in vitro. Immunoblot analysis of human serum and cerebrospinal fluid (CSF) using anti C14-module antibody, which recognizes the C-terminal peptide unique to HBCPB, detected the 30 and 40 kDa immunoreactive bands. Analysis of HBCPB prepared from both serum and CSF demonstrated proteolytic activities for brain APP. Protease inhibitor spectrum analysis also supports that these bands correspond to the mature form and and prepro form of HBCPB, respectively. As is the case in brain parenchyma, the prepro-form is dominant in CSF. In serum, however, the majority of HBCPB exists in the mature form, possibly due to an abundant trypsin-like proteolytic activity in serum. HBCPB expressed in serum and CSF, therefore, may have a significance as a peripheral marker of the brain protease, which participates in APP processing in human brain.

Alzheimer Disease↗

Induction of antitumor immunity by transduction of CD40 ligand gene and interferon-gamma gene into lung cancer.

CD40-CD40 ligand (CD40L) interaction is an important costimulatory signaling pathway in the crosstalk between T cells and antigen-presenting cells. This receptor-ligand system is known to be essential in eliciting strong cellular immunity. Here we demonstrate that murine lung cancer cells (3LLSA) transduced with the CD40L gene (3LLSA-CD40L) were rejected in syngeneic C57BL/6 mice, but grew in CD40-deficient mice to the same extent as control tumor cells. Immunohistochemical study showed that inflammatory cells, including CD4+, CD8+ T cells and NK cells, infiltrated into the inoculated 3LLSA-CD40L tumor tissue. Inoculation of 3LLSA-CD40L cells into mice resulted in the induction of 3LLSA-specific cytotoxic T-cell immunity, and the growth of parental 3LLSA tumors was inhibited when 3LLSA cells were inoculated into C57BL/6 mice mixed with 3LLSA-CD40L cells or when they were rechallenged 4 weeks after 3LLSA-CD40L cells were rejected. Furthermore, co-inoculation of interferon (IFN)-gamma-transduced cells (3LLSA-IFNgamma) with 3LLSA-CD40L cells enhanced the antitumor immunity efficiently in vivo. These results indicate that the in vivo priming with CD40L- and IFN-gamma gene-transduced lung cancer cells is a promising strategy for inducing antitumor immunity in the treatment of lung cancer.

Animals↗

Effect of erythromycin on matrix metalloproteinase-9 and cell migration.

Erythromycin (EM) has an anti-inflammatory effect that may account for its clinical benefit in the treatment of chronic inflammatory diseases such as diffuse panbronchiolitis. To investigate the mechanism of this anti-inflammatory effect, we studied the relationship between the concentration of EM and matrix metalloproteinase-9 (MMP-9) activity, which is important in cell migration. We showed that EM suppressed the gelatinolytic activity of U937 cell-derived MMP-9 by using gelatin zymography, showed that expressions of MMP-9 protein and MMP-9 mRNA were down-regulated by EM in a dose-dependent manner, and showed that U937 migration was also suppressed by EM. We also demonstrated that EM treatment suppressed the gelatinolytic activity of MMP-9 in spleen macrophages. These findings suggest that the suppressive effect of EM on MMP-9 activity is one of the anti-inflammatory mechanisms that inhibit the migration of inflammatory cells into the inflammatory site.

Anti-Bacterial Agents↗

Clarithromycin-based triple therapy for non-resistant Helicobacter pylori infection. How long should it be given?

BACKGROUND: We have previously reported mixed infection with wild-type (sensitive) and mutant (resistant) Helicobacter pylori strains using a PCR-based preferential homo-duplex formation assay (PCR-PHFA) to detect gene mutations associated with clarithromycin resistance. Half of the cases with mixed infection were determined as sensitive by conventional MIC assessment and yet failed to respond to clarithromycin-based therapy. The aim of this study is to assess the efficacy of clarithromycin-based triple therapy in patients infected exclusively with wild-type strains as determined by PCR-PHFA. METHODS: Ninety patients who had pure wild-type H. pylori infection were randomly assigned to receive clarithromycin (200 mg b.i.d.), amoxicillin (500 mg q.i.d.) and lansoprazole (30 mg b.i.d.) for either 5 days or 7 days (n = 48 and n = 42, respectively). The outcome of eradication was assessed by [13C] urea breath test. RESULTS: Eradication was achieved in 36/48 (75%) versus 39/42 (93%) by intention-to-treat analysis (P = 0.02), and in 36/45 (80%) versus 39/40 (98%) by per protocol analysis (P = 0.01), for the 5-day and 7-day protocols, respectively. Compliance and the incidence of untoward effects were similar in both groups. CONCLUSIONS: Seven-day administration is necessary and sufficient for the triple therapy with clarithromycin, amoxicillin and lansoprazole in patients with pure wild-type H. pylori infection.

2-Pyridinylmethylsulfinylbenzimidazoles↗

Neurally mediated syncope and cardiac beta-adrenergic receptor function.

To evaluate the mechanism of neurally mediated syncope (NMS), we investigated basal autonomic nerve function using a conventional pharmacological method and [123I]-metaiodobenzyl-guanidine (MIBG) single photon emission computed tomography (SPECT). Nine patients with NMS, whose syncope was induced by head-up tilt test with or without isoproterenol, underwent [123I]-MIBG SPECT. Eight of nine NMS patients showed reduced myocardial uptake (two patients, diffuse; four patients, anteroseptal and inferior; one patient, anteroseptal; one patient, inferior). In the study of pharmacological autonomic nervous function test, atropine sulfate (atr.) (0.04 mg/kg), isoproterenol (isp.) (5 x 10(-3) microg/kg/min), propranolol (prop.) (0.2 mg/kg), phenylephrine (phenyl.) (0.4 microg/kg/min), and phentolamine (phent.) (0.2 mg/kg) were successively administered to patients with NMS (n = 5) and control subjects (n = 5). The heart rate (HR) after atr. and prop., and systolic blood pressure (SBP) after phent. were defined as intrinsic HR (IHR) and intrinsic SBP (ISBP). Parasympathetic activity (increase in HR by atr.), beta-sympathetic tone (HR after atr. minus IHR), beta-sensitivity (change in HR by 1 microg isp./kg/min), beta-secretion (beta-tone/beta-sensitivity), alpha-sympathetic tone (SBP before phenyl. minus ISBP), alpha-sensitivity (change in SBP by 1 microg phenyl./kg/min) and alpha-secretion (alpha-tone/alpha-sensitivity) were also calculated. The beta-secretion was decreased (0.0027+/-0.0008 versus 0.0060+/-0.0004 microg/kg/min/isp.; p < 0.05), while the beta-sensitivity was increased (5850+/-947 versus 3150+/-292 beats/microg/kg/min isp.; p < 0.05) in NMS compared with control subjects. In the other indexes, there were no significant differences between two groups. The results of the present study suggest that increased beta-sensitivity may contribute hypercontraction of left ventricles, which might partially explain the mechanism of NMS.

3-Iodobenzylguanidine↗

Frameshift mutations at mononucleotide repeats in RAD50 recombinational DNA repair gene in colorectal cancers with microsatellite instability.

To identify additional genes targeted for microsatellite instability (MSI), we search for human genes which contain mononucleotide repeats in their coding region, selected 7 genes (RAD50, DNA-PKcs, FLASH, Apaf-1, XPG, CtIP, and MLSN1), and analyzed frameshift mutations in them. Here we report that 60% (3 out of 5) of human colorectal cancer cell lines exhibiting a high frequency of MSI (MSI-H) and 46% (6 out of 13) of MSI-H primary colorectal tumors had mutations in the (A)9 repeat of RAD50 recombinational repair gene. In contrast, no frameshift mutations were found in any of the 5 MSI-negative colorectal cancer cell lines, 8 colorectal tumors exhibiting a low frequency of MSI (MSI-L), or 28 MSI-negative colorectal tumors. No mutations were found in the mononucleotide repeats of 6 other genes, even in MSI-H cancers. These results suggest that RAD50 frameshift mutations may play a role in the tumorigenesis of MSI-H colorectal cancers.

Colorectal Neoplasms↗

Helicobacter pylori induced transactivation of SRE and AP-1 through the ERK signalling pathway in gastric cancer cells.

BACKGROUND AND AIMS: Helicobacter pylori infection induces expression of proinflammatory cytokines such as interleukin (IL)-8 and tumour necrosis factor alpha (TNF-alpha) in gastric mucosa, and their genes have AP-1 binding sites in the promoter region. c-Fos is important for transactivation of AP-1 which has SRE in the promoter region. We conducted this study to confirm H pylori induced transactivation of these binding sites. METHODS: Transactivation of SRE and AP-1 was evaluated in human gastric cancer cells TMK1 and MKN45 by luciferase reporter assay in transient transfection. We compared the effects of coculture with four H pylori strains, a cag pathogenicity island (PAI) positive strain TN2, its isogenic vacA negative (TN2-DeltavacA) or cagE negative (TN2-DeltacagE) mutants, and a cag PAI negative clinical isolate T68. Phosphorylation of ERK1/2, JNK, and c-Jun was measured by immunoblot, induction of IL-8 secretion by ELISA, and the effects of MEK by inhibitor U0126. RESULTS: Both SRE and AP-1 were transactivated by coculture with TN2. Although TN2-DeltavacA induced comparable transactivation, TN2-DeltacagE and T68 showed decreased transactivation of SRE (65% and 51%) and AP-1 (71% and 54%, respectively, of TN2). Heat killed TN2 or indirect contact using a permeable membrane inhibited transactivation. Levels of phosphorylated ERK1/2, JNK, and c-Jun were increased by coculture with TN2. MEK inhibitor U0126 reduced TN2 induced transactivation of SRE and AP1, as well as secretion of IL-8, by 83%, 87%, and 53%, respectively, of TN2. CONCLUSIONS: Transactivation of SRE and AP-1, through ERK/MAPK and JNK/SAPK cascades, respectively, was found in gastric cancer cells cocultured with H pylori. Direct contact with viable bacteria possessing intact cag PAI is a prerequisite for the onset of intracellular signalling leading to AP-1 transactivation.

Animals↗

Inverse background of Helicobacter pylori antibody and pepsinogen in reflux oesophagitis compared with gastric cancer: analysis of 5732 Japanese subjects.

BACKGROUND: The relationship between Helicobacter pylori and reflux oesophagitis remains controversial. AIMS: To evaluate the relationship between H pylori and reflux oesophagitis in a large number of Japanese subjects. SUBJECTS: A total of 5732 consecutive Japanese subjects during a health screening were enrolled. METHODS: Gastrointestinal endoscopy was performed on all subjects. We simultaneously measured serum anti-H pylori antibody and pepsinogen as markers of H pylori infection together with gastric atrophy. The risk of reflux oesophagitis was evaluated in relation to these markers, and the results were compared with those of gastric cancer. RESULTS: Reflux oesophagitis was found in 108 subjects. Both positivity for H pylori antibody (adjusted odds ratio (OR) 0.67 (95% confidence interval 0.45-1.0)) and "low" pepsinogen indicating gastric atrophy (OR 0.35 (0.18-0.68)) were negatively associated with reflux oesophagitis. After subjects were classified into four groups based on positivity or negativity for H pylori antibody and "low" pepsinogen, the prevalence of reflux oesophagitis showed a decreasing trend as H pylori induced gastric atrophy became more severe. The risk of gastric cancer showed an increasing trend, exactly the opposite to that of reflux oesophagitis. CONCLUSIONS: Analysis of a large series of Japanese subjects revealed a decreasing prevalence of reflux oesophagitis in conjunction with progress of gastric atrophy induced by H pylori infection. This pattern was completely opposite to that of gastric cancer cases. A protective role of H pylori for reflux oesophagitis through the development of gastric atrophy has been suggested.

Adult↗

[Treatment of chronic hepatitis C patients complicated with the other disease].

Because of relatively low efficacy, considerable side effect and high cost, HCV infected patients complicated with the other disease(patients with hematologic dysorders, chronic renal failure on hemodialysis, HIV co-infection and collagen disease) have been excluded from large trials evaluating the efficacy of IFN or in combination with ribabirin. So, little is known about treatment of these patients. We analyzed the medical literature focusing on treatment of HCV infection in these patients, to suggest conclusion about indication based on tolerance and efficacy. In case the other disease is well controlled and long term sevival is expected, treatment should be required based on the evaluation of liver function test including liver pathology for preventing liver disease from developing terminal stage. Further studies are needed to better define HCV therapies in these patients.

Collagen Diseases↗

Identification of basic residues involved in drug export function of human multidrug resistance-associated protein 2.

Multidrurg resistance-associated protein 2 (MRP2)/canalicular multispecific organic anion transporter (cMOAT) is involved in the ATP-dependent export of organic anions across the bile canalicular membrane. To identify functional amino acid residues that play essential roles in the substrate transport, each of 13 basic residues around transmembrane regions (TMs) 6-17 were replaced with alanine. Wild type and mutant proteins were expressed in COS-7 cells, and the transport activity was measured as the excretion of glutathione-methylfluorescein. Four mutants, K324A (TM6), K483A (TM9), R1210A (TM16), and R1257A (TM17), showed decreased transport activity, and another mutant, K578A (TM11), showed decreased protein expression. These five mutants were normally delivered to the cell surface similar to the other fully active mutants and wild type MRP2. The importance of TM6, TM16, and TM17 in the transport function of MRP2 is consistent with the previous observation indicating the importance of the corresponding TM1, TM11, and TM12 on P-glycoprotein (Loo, T. W., and Clarke, D. M. (1999) J. Biol. Chem. 274, 35388-35392). Another observation that MRP2 inhibitor, cyclosporine A, failed to inhibit R1230A specifically, indicated the existence of its binding site within TM16.

ATP Binding Cassette Transporter, Subfamily B↗

Differential regulation of human RecQ family helicases in cell transformation and cell cycle.

Three human RecQ DNA helicases, WRN, BLM and RTS, are involved in the genetic disorders associated with genomic instability and a high incidence of cancer. RecQL1 and RecQL5 also belong to the human RecQ helicase family, but their correlation with genetic disorders, if any, is unknown. We report here that in human B cells transformed by Epstein-Barr virus (EBV), human fibroblasts and umbilical endothelial cells transformed by simian virus 40, the expression of WRN, BLM, RTS and RecQL1 was sharply up-regulated. In B cells this expression was stimulated within 5-40 h by the tumor promoting agent phorbol myristic acetate (PMA). Interestingly, RecQL5beta, an alternative splicing product of RecQL5 with a nuclear localization signal, is expressed in resting B cells without significant modulation of its synthesis by EBV or PMA, suggesting it has a role in resting cells. We also roughly determined the number of copies per cell for the five RecQ helicase in B cells. In addition, levels of the different RecQ helicases are modulated in different ways during the cell cycle of actively proliferating fibroblasts and umbilical endothelial cells. Our results support the view that the levels of WRN, BLM, RTS and RecQL1 are differentially up-regulated to guarantee genomic stability in cells that are transformed or actively proliferating.

Adenosine Triphosphatases↗

Cimetidine inhibits cancer cell adhesion to endothelial cells and prevents metastasis by blocking E-selectin expression.

Although the beneficial effect of cimetidine on survival in cancer has been clinically demonstrated in colorectal cancer patients, the mode of action of cimetidine has not been elucidated. In this report, we have demonstrated for the first time that cimetidine can block the adhesion of a colorectal tumor cell line to the endothelial cell monolayer in cell culture and that it can suppress the metastasis of the tumor cell in a nude mouse model. We also demonstrated that these antimetastasis effects of cimetidine might occur through down-regulation of the cell surface expression of E-selectin on endothelial cells, a ligand for sialyl Lewis antigens on tumor cells. We found that the cimetidine-mediated down-regulation of E-selectin did not involve down-regulation of E-selectin mRNA or blocking of the nuclear translocation of nuclear factor kappaB, a transcriptional activator of E-selectin gene expression. Because two other histamine type 2 receptor antagonists, famotidine and ranitidine, did not show any similar effect, these actions of cimetidine probably do not occur via blocking of the histamine receptor. These observations support the idea that cancer metastasis can be blocked by cimetidine administration through blocking the adhesion of tumor cells to the endothelium when an interaction between E-selectin and sialyl-Lewis antigens plays a role.

Animals↗

Involvement of nitric oxide in endothelium-dependent arterial relaxation by leptin.

Leptin is a polypeptide, mainly produced in white adipose tissue, and increases sympathetic nerve activity. A few studies investigated leptin's effect on peripheral vessels. We examined the vasorelaxant effects of human leptin on rat arteries. Arterial rings were precontracted with 1 x 10(-6) mol/l of phenylephrine, and leptin was superfused. Leptin relaxed phenylephrine-precontracted arterial rings in a dose-dependent manner. ED50 was calculated to 8.4 microg/ml. Removal of endothelium abolished the effects of leptin. Indomethacin (1 x 10(-5) mol/l) did not affect the vasorelaxation by leptin, whereas 1 x 10(-4) mol/l of N(omega)-nitro-L-arginine methyl ester (L-NAME) completely suppressed it. The inhibition was antagonized by 1 x 10(-4) mol/l of L-arginine. Leptin normally relaxed arterial rings during superfusion of K channel blockers, including 3 x 10(-5) mol/l of glibenclamide, 1 x 10(-6) of mol/l apamin, and 5 x 10(-7) mol/l of charybdotoxin. Low Cl(-) solution (8. 3 mmol/l) inhibited leptin-induced relaxation, but endothelium-independent vasodilatation by nitroprusside was not impaired at low Cl(-) solution. These results suggest that arterial relaxation by leptin is mediated by nitric oxide released from endothelium, and Cl(-) plays an important role in leptin-induced nitric oxide release.

Acetylcholine↗

Comparison of biotin production by recombinant Sphingomonas sp. under various agitation conditions.

Biotin production by fermentation of recombinant Sphingomonas sp./pSP304 was investigated. A complex medium containing 60g/l of glycerol and 30g/l of yeast extract was suitable for biotin production. Biotin was produced in the late logarithmic or stationary phase after glycerol starvation. The optimum pH value for biotin production was 7.0. When the dissolved oxygen concentration (DO) was controlled at a constant level, the biotin concentration produced after 120h was significantly lower than that obtained in a test tube culture. Therefore, a batchwise jar-fermentor culture with a constant agitation speed and without DO control was conducted for investigating the effect of agitation conditions on biotin production. Six types of impeller were tested: turbine-blade type, turbo-lift type, rotating mesh type (EGSTAR((R))), screw with draft tube type, Maxblend((R))type, and anchor type. With some impellers, agitation speed was also changed. Both the maximum cell concentration and biotin production varied depending on agitation conditions. Relatively high cell concentrations were attained with four of the impeller types, turbine-blade type, rotating mesh type, Maxblend((R)) type, and anchor type. Among these impellers, the turbine-blade impeller with sintered sparger was suitable for biotin production. After 120h, the cell concentration reached an OD(660) of 43 and a biotin concentration of 66mg/l was obtained, which was comparable with the results from the test tube culture. Morphological variation was also observed depending on the agitation conditions: oval-shaped, rod-shaped, and elongated-shaped cells. Biotin production was relatively high in slightly long rod-shape cells but low in elongated cells. The difference in morphology appeared to depend on the shear stress. It was found that biotin production was strongly correlated with cell length and the oxygen transfer coefficient (k(L)a); cell lengths in the range 4-7µm and k(L)a values in the range 1.5-2.0/min were found to be suitable for biotin production in jar-fermentor culture.

Journal Article↗

Assessment of gastric carcinoma risk associated with Helicobacter pylori may vary depending on the antigen used: CagA specific enzyme-linked immunoadsorbent assay (ELISA) versus commercially available H. pylori ELISAs.

BACKGROUND: Previous epidemiologic studies produced inconsistent results when examining the relation between Helicobacter pylori infection and the risk of gastric carcinoma by measuring various anti-H. pylori antibodies. This study investigated the increased risk of cancer by examining different antibodies, including the specific anti-CagA antibody and antibodies from two commercially available kits. METHODS: An ELISA for the detection of serum anti-CagA was established using a recombinant CagA protein that the authors previously reported. Serum anti-CagA titer was determined for 80 patients with gastric carcinoma and 80 gender- and age-matched controls. Two anti-H. pylori antibodies from the commercially available kits HEL-p (Amrad, Kew Vic, Australia) and HM-CAP (Enteric Product Inc., Westbury, NY) were also evaluated. RESULTS: Anti-CagA seropositivity differed significantly between gastric carcinoma patients and controls (92.5% vs. 55.0%; P = 0. 0001), showing an odds ratio of 10.4 (95% confidence interval [CI]: 4.23-29.74). The difference was less prominent for the seropositivity of HEL-p (77.5% vs. 58.8%; P = 0.0139; odds ratio: 2. 38; 95% CI: 1.20-4.82) and insignificant for that of HM-CAP (65.0% vs. 57.5%; P = 0.4325; odds ratio: 1.30; 95% CI: 0.68-2.49). CONCLUSIONS: The current study revealed that the antibody assay system used could be one important factor in the assessment of gastric carcinoma risk for patients with H. pylori.

Adult↗