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T Horie

Publications and source records attributed to T Horie.

At least 19 recordsLinked to original sources
PubMed2005

Evaluation of mRNA expression of human drug-metabolizing enzymes and transporters in chimeric mouse with humanized liver.

The hepatic mRNA expression of human drug-metabolizing enzymes and transporters in chimeric mise with almost-completely humanized liver (replacement index: 71-89%) was investigated. The mRNAs of 58 human phase I enzymes, 26 human phase II enzymes, 23 human transporters, and five mouse Cyps were measured in the chimeric mice with humanized liver generated using hepatocytes from a Japanese donor. The mRNA expression of 52 human phase I enzymes, which includes 20 human CYPs, 26 human phase II enzymes and 21 human transporters was ascertained in the chimeric mouse liver. Among them, the expression of the target mRNAs vital for liver function such as the metabolism and secretion of endogenous compounds appeared to be maintained. The central value for the expression ratio in all target genes in chimeric mouse liver to the donor liver was 0.46, which was lower than the substitution rate of chimeric mouse liver by donor liver. The ratio of mouse Cyp mRNA expression of chimeric mouse liver to that of control mouse liver was 0.19 or less, except for that of Cyp2b10. There were good correlations between the mRNA expression levels of human hepatic albumin gene, the values of the rate of replacement of mouse liver by human liver, and the human blood albumin concentration in the chimeric mice. The chimeric mice with humanized liver may be a useful tool for the evaluation of drug-drug interactions such as the inhibition and induction of drug-metabolizing enzymes and transporters.

Animals↗
PubMed2005

WT1 expression level and clinical factors in multiple myeloma.

Although Wilm's Tuomor gene (WT1) was first identified as a tumor suppressor gene for Wilm's tumor, WT1 overexpression has been detected in different malignant cell types including leukemia. Increased expression of WT1 in acute leukemia is potentially used as a marker of minimal residual disease. However, the significance of the gene for multiple myeloma is still not clear. To determine the clinical relevance of WT1 expression in multiple myeloma, we examined the association of clinical parameters and WT1 expression in bone marrow for 17 newly diagnosed multiple myeloma patients. WT1 was assessed by real-time quantitative polymerase chain reaction (RQ-PCR) and calculated standardized WT1 expression level per 100 plasma cells in the bone marrow specimen as "corrected WT1". The expression of standardized WT1 and corrected WT1 in myeloma was 59 to 1,600 copies/microg RNA and 0.05 to 406.3 copies/microg RNA/100 plasma cells, respectively, lower than in leukemia. WT1 transcripts increased when clinical factors worsen, including the stage, amount of M protein, Hb, platelet count, blood urea nitrogen (BUN), creatinine, serum alkaline phosphatase (ALP), calcium, beta2-microglobulin, thymidine kinase activity (TK), and C-reactive protein (CRP). In conclusion, the expression level of WT1 could be an additional marker to the standard parameters considered in risk assessment for multiple myeloma.

Biomarkers, Tumor↗
PubMed2004

Oxidative stress contributes to methotrexate-induced small intestinal toxicity in rats.

BACKGROUND: Gastrointestinal toxicity is one of the most serious side effects in the methotrexate (MTX) treatment. However, the mechanism of the toxicity has not been completely clarified, which may be the reason why symptomatic therapy is carried out. On the other hand, the oxidative stress is known to play an important role in various diseases and drug-induced side effects. In this study the focus was on the oxidative stress in order to clarify the mechanism of MTX-induced small intestinal damage, especially neutrophil infiltration. METHODS: MTX (20 mg/kg body wt) was administered to rats intravenously. Mucosal homogenates were prepared from the small intestine and used for assay of biochemical parameters, by which induction of oxidative stress and neutrophil infiltration were evaluated. N-acetylcysteine (NAC; 80 mg/kg body wt), an antioxidant or sodium tungstate (tungsten; 0.7 g/kg body wt), an inhibitor of xanthine dehydrogenase (XD)/xanthine oxidase (XO) known as an important source of reactive oxygen species (ROS) was given to rats with MTX to investigate the contribution of ROS to neutrophil infiltration. RESULTS: The MTX treatment of rats induced the oxidative stress in the small intestine. The ROS production was seen preceding an increase of myeloperoxidase activity, which suggested neutrophil infiltration. Both treatments of NAC and tungsten prevented the MTX-induced ROS production and neutrophil infiltration. CONCLUSIONS: These results suggest that oxidative stress plays an important role in the MTX-induced small intestinal damage, especially neutrophil infiltration. Thus, the modulation of oxidative stress would be useful in reducing intestinal damage in MTX treatment.

Acetylcysteine↗
PubMed2003

Prevalence of Helicobacter pylori in NSAID users with gastric ulcer.

OBJECTIVE: Regarding the interaction of Helicobacter pylori and non-steroidal anti-inflammatory drugs (NSAIDs), we cannot accept unanimous conclusions in inducing gastric ulcer. We therefore evaluated the role of Helicobacter pylori and NSAIDs in inducing gastric ulcer. METHODS: Dyspeptic patients receiving NSAIDs underwent endoscopic examination. Gastric ulcer formation and H. pylori status were investigated. Biopsy specimens from the antrum and lower body of the stomach were prepared for the rapid urease test and pathological evaluation. Anti-H. pylori antibody was measured by enzyme-linked immunosorbent assay. RESULTS: Two hundred and twenty-six patients receiving NSAIDs (220 chronic and six on-demand users) underwent gastrofibrescopic examination. There were 110 patients with gastric ulcer and 111 non-ulcer patients with gastritis. The remaining five patients had neither. NSAID users with gastric ulcer showed a low prevalence of H. pylori compared with those without them [55/110 (50.0%) vs 79/111 (71.2%), P < 0.01]. The same tendency was seen when patients receiving low-dose aspirin and those with rheumatoid arthritis were analysed separately [13/29 (44.8%) vs 50/62 (80.6%), P < 0.01, and 11/33 (33.3%) vs 16/26 (61.5%), P < 0.06 with Yates' correction, respectively]. CONCLUSION: Helicobacter pylori infection appeared to be a risk factor for developing gastritis, but we found no evidence that it increases gastric ulcer formation in NSAID users with dyspepsia.

Aged↗
PubMed2003

Role of mitogen-activated protein kinases in influenza virus induction of prostaglandin E2 from arachidonic acid in bronchial epithelial cells.

BACKGROUND: Influenza virus (IV) infection causes airway inflammation; however, it has not been determined whether IV infection could catabolize arachidonic acid cascade in airway epithelial cells. In addition, the responsible intracellular signalling molecules that catabolize arachidonic acid cascade have not been determined. OBJECTIVE: In the present study, to clarify these issues, we examined the cyclooxygenase (COX) expression, cytosolic phospholipase A2 (cPLA2) phosphorylation and prostaglandin E2 (PGE2) release in human bronchial epithelial cells (BEC) upon IV infection, and the role of mitogen-activated protein kinase (MAPK) including extracellular signal-regulated kinase (ERK), p38 MAPK and c-Jun-NH2-terminal kinase (JNK) in catabolizing arachidonic acid cascade in BEC. METHODS: COX-2 expression, phosphorylation of cPLA2 and phosphorylation of ERK, JNK and p38 MAPK were determined by Western blot. The concentrations of PGE2 were determined by ELISA. PD 98059 as a specific inhibitor of MAPK kinase-1 (MEK-1), an up-stream kinase of ERK, SB 203580 as a specific inhibitor of p38 MAPK and CEP-11004 as a specific inhibitor of JNK cascade were used to investigate the role of ERK, p38 MAPK and JNK in catabolizing arachidonic acid cascade in BEC. RESULTS: The results showed that (1) IV infection increases COX-2 expression, cPLA2 phosphorylation and PGE2 release, (2) ERK, p38 MAPK and JNK were phosphorylated, (3) CEP-11004 and PD 98059 predominantly attenuated COX-2 expression and cPLA2 phosphorylation, respectively, (4) SB 203580 did not remarkably affect COX-2 expression and cPLA2 phosphorylation, and (5) each inhibitor dose-dependently attenuated PGE2 release by various extents. CONCLUSION: These results indicate that IV infection activates three distinct MAPKs, ERK, p38 MAPK and JNK, to participate to various extents in the induction of PGE2 synthesis from arachidonic acid in BEC.

Arachidonic Acid↗
PubMed2003

Effects of non-steroidal anti-inflammatory drugs on the methotrexate transport in rat small intestine.

BACKGROUND: Methotrexate (MTX) is used in the treatment of rheumatic disease, sometimes along with non-steroidal anti-inflammatory drugs (NSAIDs), and is actively co-transported with H+ in the small intestine, mediated by a reduced folate carrier (RFC). The co-administration of NSAIDs with MTX might cause a decrease in MTX absorption through the small intestine, since some NSAIDs are uncouplers of oxidative phosphorylation. The present study investigates whether flufenamic acid, diclofenac and indomethacin, NSAIDs, decrease the ATP content of small intestinal epithelial cells and affect MTX transport (the secondary active transport) in the small intestine. METHODS: MTX transport was examined in the presence and absence of the NSAIDs, using the everted intestine technique and brush border membrane vesicles (BBMVs) from the rat small intestine. The change in physical properties of the membrane was studied in BBMVs using the fluorescence techniques. RESULTS: MTX absorption in the small intestine with H+ gradient (mucosal side, pH 6.0; serosal side, pH 7.4) decreased in the presence of the NSAIDs, but absorption without H+ gradient (both sides, pH 7.4) was unaffected. The intestinal mucosal ATP content decreased in the presence of the NSAIDs. The uptake of MTX in BBMVs was unaffected by the NSAIDs. The activity of intestinal Na+-K+-ATPase was enhanced in the presence of the NSAIDs. The fluorescence measurements showed that membrane fluidity, membrane potential and membrane hydrophobicity of BBMVs were unaffected by the NSAIDs. CONCLUSIONS: NSAIDs decreased the H+/MTX absorption in the small intestine, but not the passive transport. The uncoupling effect of the NSAIDs decreased the ATP content in the small intestine, resulting in inhibition of the secondary active transport.

Animals↗
PubMed2003

The relationship between oxidative metabolism and lipid peroxidation in rat liver microsomes.

7-ethoxycoumarin was not found to induce lipid peroxidation in rat liver microsomes, although it was reported to cause lipid peroxidation in rat cultured hepatocytes. The productions of thiobarbituric acid reactive substances (TBARS) and chemiluminescence (CL) in the presence of some drugs including tolbutamide, naproxen and salicylic acid and their oxidation activities were determined. There was a negative correlation between extent of oxidative stress and oxidation activities. These results suggested that the oxidative metabolism of these drugs did not directly contribute to the microsomal peroxidation reaction. In addition, naproxen-induced microsomal lipid peroxidation was found to occur in rat, but did not in guinea pig.

Animals↗
PubMed2002

Toxicity of ethacrynic acid in isolated rat hepatocytes.

Ethacrynic acid, a loop diuretic drug, caused lipid peroxidation in isolated rat hepatocytes. The thiobarbituric acid reactive substances (TBARS) formation showed a good correlation with the leakage of glutamic-oxaloacetic acid transaminase (GOT) from the hepatocytes. The addition of antioxidants such as N, N'-diphenyl-p-phenylenediamine (DPPD) and promethazine to the isolated rat hepatocyte suspension containing ethacrynic acid prevented the lipid peroxidation and decreased the GOT leakage to some extent. SKF-525A inhibited the oxidative metabolism of ethacrynic acid and decreased the TBARS formation, suggesting that the lipid peroxidation was caused by the oxidative metabolism. The intracellular reduced glutathione markedly decreased in the hepatocyte suspension containing ethacrynic acid and the hepatocellular protein sulfhydryls were decreased, which was negatively correlated with the GOT leakage. Thus the ethacrynic acid-induced hepatotoxicity was found to be related to the lipid peroxidation and the decrease of cellular protein sulfhydryls.

Animals↗
PubMed2002

Long-term administration of beraprost, an oral prostacyclin analogue, improves pulmonary diffusion capacity in patients with systemic sclerosis.

The objective of this study was to assess the effect of beraprost sodium, an oral prostacyclin analogue, on pulmonary function in patients with systemic sclerosis. Seventeen patients, with systemic sclerosis and predicted percent values of carbon monoxide diffusion capacity (%DLCO) of less than 95, received beraprost sodium for at least 12 months. Conventional testing for pulmonary function was performed at 12-month intervals and changes were evaluated with special reference to DLCO. Twelve patients completed the treatment. Nine patients showed improvement in DLCO (12.1 +/- 2.3 to 15.5 +/- 4.4 ml/min/mmHg, P < 0.006) and 10 patients showed an increase in %DLCO (66.6 +/- 11.9 to 87.7 +/- 23.2%, P < 0.004). Total lung capacity, vital capacity and forced expiratory volume remained unchanged. This study showed that DLCO levels in patients with systemic sclerosis improved after the administration of beraprost sodium, probably due to the decrease in pulmonary vascular resistance accompanied by increased cardiac output.

Administration, Oral↗
PubMed2002

Patients with systemic lupus erythematosus show a normal responsive search score in exploratory eye movement analysis: comparison with schizophrenia.

OBJECTIVE: To assess whether a difference in psychiatric vulnerability exists between patients with systemic lupus erythematosus (SLE) and those with schizophrenia. METHODS: Twenty women with SLE underwent exploratory eye movement analysis, and a responsive search score (RSS) was obtained, two months after the onset of the disease. Fifteen women with schizophrenia in remission also underwent this analysis. Exploratory eye movement was recorded by an eye mark recorder, which detects corneal reflection of infrared light. The number of eye fixations (instance of more than 0.2 seconds of eye fixation time) was recorded, and the RSS was calculated from eye fixation analysis. RESULTS: Mean (SD) RSS differed significantly between patients with SLE and those with schizophrenia (9.85 (1.87) v 7.27 (1.58) points, respectively, p<0.0001), whereas no difference in mean RSS was found between patients with SLE and 19 normal women. No difference in mean RSS was found between patients with active SLE and those with inactive SLE (9.51 (1.87) v 10.0 (1.77) points). CONCLUSION: The psychiatric vulnerability in patients with SLE, measured by the RSS, differs from that in patients with schizophrenia.

Adult↗
PubMed2002

Fatal cases of gabexate mesilate-induced anaphylaxis.

Gabexate mesilate, ethyl-4-(6-guanidinohexanoyloxy) benzoate monomethanesulfonate (C16H23N3 O4CH4O3S: M.W. 417.48), is a synthetic protease inhibitor and was introduced for clinical use in 1978. It rarely induces anaphylaxis, and patients with gabexate mesilate-induced shock had been reported to survive with appropriate treatments including respiratory support. However, there were increasing reports on fatal cases in recent years: 6 cases have been reported to develop fatal anaphylaxis following dripping infusions of gabexate mesilate. All the fatal cases rapidly developed anaphylaxis (within 5 minutes), whereas 7 out of 11 in recovered cases developed it 5 or more minutes after the injection. Venous access should be kept for at least 30 minutes to prepare for and to treat this fatal reaction in patients receiving gabexate mesilate repeatedly.

Anaphylaxis↗
PubMed2001

Characteristics of transport of fluoresceinated methotrexate in rat small intestine.

The small intestinal damage induced by the methotrexate (MTX) treatment results in malabsorption and diarrhea. The fluoresceinated methotrexate (F-MTX) may possibly be useful to study such effects of MTX on the small intestine. The purpose of this study is to characterize the transport of F-MTX in the small intestine in order to use it as a membrane transport and cellular marker of MTX. The transport of F-MTX in the rat small intestine (jejunum) was examined in the in vitro everted segments of the intestine. The uptake was pH-dependent and showed a maximal effect at pH 6.0, which was the same as the results of MTX previously reported. Further, it was temperature-dependent and was inhibited by metabolic inhibitors, dinitrophenol and sodium azide, and by MTX. The transport kinetics at pH 6.0 in the mucosal solution and at pH 7.4 in the serosal solution was saturable with Km of 0.48 +/- 0.23 microM and Vmax of 0.66 +/- 0.24 pmol/cm/min and in addition, the passive diffusion was observed there. These results suggested that the transport of F-MTX was energy-dependent and was mediated by the same transporter as that of MTX, although, in addition to it, other transport mechanism might contribute to the F-MTX transport. Therefore F-MTX will be of great use to investigate the MTX transport system in the normal and diseased states of small intestine, using various fluorescence techniques like visualization of membrane-associated transport proteins.

Animals↗
PubMed2001

Oxidative stress in the absence of inflammation in a mouse model for hepatitis C virus-associated hepatocarcinogenesis.

The mechanism of hepatocarcinogenesis in hepatitis C virus (HCV) infection is still undefined. One possibility is the involvement of oxidative stress, which can produce genetic mutations as well as gross chromosomal alterations and contribute to cancer development. We recently showed that after a long period, the core protein of HCV induces hepatocellular carcinoma (HCC) in transgenic mice with marked hepatic steatosis but without inflammation, indicating a direct involvement of HCV in hepatocarcinogenesis. To elucidate the biochemical events before the development of HCC, we examined several parameters of oxidative stress and redox homeostasis in a mouse model of HCV-associated HCC. For young mice ages 3-12 months, there was no significant difference in the levels of hydroperoxides of phosphatidylcholine (PCOOH) and phosphatidylethanolamine in liver tissue homogenates between transgenic and nontransgenic control mice. In contrast, the PCOOH level was increased by 180% in old core gene transgenic mice > 16 months old. Concurrently, there was a significant increase in the catalase activity, and there were decreases in the levels of total and reduced glutathione in the same mice. A direct in situ determination by chemiluminescence revealed an increase in hydroperoxide products by 170% even in young transgenic mice, suggesting that hydroperoxides were overproduced but immediately removed by an activated scavenger system in young mice. Electron microscopy revealed lipofuscin granules, secondary lysosomes carrying various cytoplasmic organelles, and disruption of the double membrane structure of mitochondria, and PCR analysis disclosed a deletion in mitochondrial DNA. Interestingly, alcohol caused a marked increase in the PCOOH level in transgenic mice, suggesting synergism between alcohol and HCV in hepatocarcinogenesis. The HCV core protein thus alters the oxidant/antioxidant state in the liver in the absence of inflammation and may thereby contribute to or facilitate, at least in part, the development of HCC in HCV infection.

Animals↗
PubMed2001

The role of distinct p185neu extracellular subdomains for dimerization with the epidermal growth factor (EGF) receptor and EGF-mediated signaling.

The extracellular domain of p185(c-neu) can be viewed as a complex structure of four subdomains, two of which are cysteine-rich subdomains. We have investigated the contribution of these distinct p185(c-neu) extracellular subdomains to p185/epidermal growth factor receptor (EGFR) heteromer formation and EGF-induced heteromeric signaling. Our studies indicate that at least two separate p185 subdomains, a region spanning subdomains I and II and subdomain IV are involved in association of p185 with the EGFR. We also demonstrated that subdomain IV reduced the heteromeric signaling and transforming activities induced by EGF after associating with EGFR. When 126 aa were deleted from subdomain IV, this small subdomain IV-derived fragment could still lead to heterodimers with EGFR and suppress EGF-induced mitogen-activated protein kinase activation and subsequent transformation abilities. These data provide information about trans-inhibitory mechanisms of mutant p185 species and also indicate that both the entire and a part of subdomain IV may represent a therapeutic target for erbB-overexpressing tumors. Finally, these studies define a basic feature of receptor-receptor associations that are determined by cystine-knot containing subdomains.

Animals↗
PubMed2001

Expression of thioredoxin in bleomycin-injured airway epithelium: possible role of protection against bleomycin induced epithelial injury.

Bleomycin (BLM) is an anticancer drug, administration of which leads to severe lung injury, in which the generation of intracellular reactive oxygen species (ROS) is thought to participate in that. Thioredoxin (TRX) has been found to function as a powerful antioxidant by reducing ROS, and thus protecting against ROS-mediated cytotoxicity. However, a protective role of TRX in BLM-induced lung injury has not been determined. In the present study, we therefore attempted to clarify this issue. Human TRX-transfected L929 murine fibrosarcoma cells were more resistant to BLM-induced cytotoxicity than the parental and the control transfected cells, indicating that TRX plays the protective role in BLM-induced cytotoxicity. Next, we examined TRX expression in the lung of in vivo model of BLM-induced lung injury and BLM-stimulated bronchial epithelial cells in vitro to clarify the role of TRX in BLM-induced lung injury. In the lungs of BLM-treated mice, the expression of TRX was strongly induced in bronchial epithelial cells. TRX expression was also up-regulated at both the mRNA and protein levels in cultured BEC with the treatment with BLM. However, the expression of other major antioxidants, such as Cu/Zn-SOD, Mn-SOD, catalase and glutathione peroxidase, was not affected by BLM. These observations suggest that the cellular reduction and oxidation (redox) state modified by TRX is involved in the BLM resistancy and the induction of TRX in bronchial epithelial cells might play a protective role in BLM-induced lung injury.

Animals↗
PubMed2001

High-performance liquid chromatographic analysis of the sulfation of 4-hydroxypropranolol enantiomers by monkey liver cytosol.

We developed a new high-performance liquid chromatographic method using an ODS column and a chiral column for the assay of racemic 4-OH-PL sulfate and enantiomeric 4-OH-PL sulfates, respectively. The method was successfully applied to measure phenolsulfotransferase (PST) activities for 4-OH-PL in cytosolic fractions from livers of Japanese monkeys (Macaca fuscata) and for comparison with its activity of cytosolic fractions from rat, rabbit, dog, and human livers and Hep G2 cells. The activity was ranked as Hep G2 cells > monkeys = humans = dogs = rats > rabbits. To evaluate the Japanese monkey as a nonhuman animal model in drug metabolism studies, we further characterized sulfation of 4-OH-PL as a further metabolic pathway in monkey livers to compare that with human livers. Inhibition studies in which cytosolic fractions were preincubated at 43 degrees C or 2,6-dichloro-4-nitrophenol (DCNP) used as a PST inhibitor indicated that two kinds of PSTs, thermolabile, low-Km and DCNP-resistant PST and thermostable, high-Km and DCNP-sensitive PST were involved in 4-OH-PL sulfation by monkey liver cytosol, which is very similar to the reported profile of 4-OH-PL sulfation by human liver cytosol. Sulfation kinetics in a low concentration range of 4-OH-PL enantiomers demonstrated that apparent Km values were similar between human and monkey liver cytosolic fractions, but the Vmax values were different, so that intrinsic clearance values (Vmax/Km, Clint) were higher in monkeys than in humans. Furthermore, enantiomer selectivity of [R(+)-4-OH-PL > S(-)-4-OH-PL] was observed in the Vmax and CLint values of monkey liver cytosol. These results indicate that the profile of sulfation of 4-OH-PL by liver cytosolic fractions is similar in humans and Japanese monkeys.

Adult↗