Biomedical subjects

T Horie

Publications and source records attributed to T Horie.

At least 127 records · Page 7Linked to original sources

PubMed1999

Mitogen-activated protein kinase involves neutrophil elastase-induced morphological changes in human bronchial epithelial cells.

Neutrophil elastase (NE) promotes the detachment of airway epithelial cells; however, changes in overall morphology of NE-stimulated bronchial epithelial cell (BEC) monolayer are different from trypsin stimulation. Ras/Raf-initiated-mitogen activated protein kinase (MAPK) also known as extracellular signal-regulated kinase, pathway regulates integrin functions which participate in regulating attachment and detachment of cell and cellular morphology. However, little is known about the role of MAPK in NE-induced changes in overall morphology of BEC. In the present study, we examined the role of MAPK in NE-induced changes in overall morphology of BEC monolayer. To this end, we examined changes in cellular morphology and MAPK activation in NE-stimulated BEC monolayer, and the effect of PD 98059 as the specific inhibitor for MAPK kinase-1 (MEK-1, the upstream regulator of MAPK) on NE-induced changes in cellular morphology and MAPK activation. The results showed that in stimulation of NE, BECs detached and gaps developed, and MAPK activation was observed. PD 98059 attenuated NE-induced changes in cellular morphology as well as MAPK activation. These results indicated that in addition to proteolytic activity of NE on extracellular matrix (ECM), NE-activated MAPK pathway, at least in part, is involved in NE-induced changes in overall morphology and the detachment of BEC monolayer.

Bronchi↗

PubMed1999

Effects of isoproterenol on IL-2 and cAMP production in peripheral T cells from asthmatic and non-asthmatic subjects sensitive to Candida.

Immunity to Candida albicans (Candida) is characterized by a Th-1 type pattern of reactivity. Candida is rarely a cause antigen for bronchial asthma. Beta agonists have been found to inhibit secretion of IL-2 from T cells through intracellular cAMP elevation. We examined effects of isoproterenol (ISO) on Candida-stimulated T cells. Peripheral T cells obtained from six Candida-sensitive asthmatics, six Candida-sensitive non-asthmatic subjects, and six normal donors by Ficoll-Hypaque gradient centrifugation and nylon-wool column chromatography were incubated with Candida antigen or concanavalin A (Con A) in the absence or presence of ISO. Secretion of IL-2 and intracellular accumulation of cAMP were assayed by ELISA. Con A induced secretion of IL-2 in each of the three groups. Candida antigen induced IL-2 secretion in the normal and the non-asthmatic subjects, but not in the asthmatics. ISO, which reduced Con A-induced secretion of IL-2 in a dose-dependent manner, had no effect on Candida-induced secretion of IL-2. Although ISO increased the intracellular concentration of cAMP in untreated and Con A-treated T cells from all donors, cells from the normal and the non-asthmatic subjects, but not from the asthmatics, that were co-incubated with ISO and Candida had lower levels of cAMP than those treated with ISO alone. It is suggested that Candida antigen induces secretion of IL-2 and reduces ISO-inducible accumulation of cAMP in Candida-responsive IL-2 secreting cells, which may make Candida-induced secretion of IL-2 insensitive to ISO.

Asthma↗

PubMed1999

Protein crystals in Phycomyces sporangiophores are involved in graviperception.

The sporangiophores of the zygomycete fungus Phycomyces blakesleeanus contain octahedral crystals with diameters of up to 5 micrometers in their vacuole. The crystals are associated with the intracellular membrane system. In tilted or horizontally placed sporangiophores, the crystals sediment to the respective lower face of the vacuole with a velocity of up to 100 micrometers per minute. The sedimentation is completed within about 2 minutes, well within the latency period for the negative gravitropic response of Phycomyces. Crystal-lacking mutant strains display a smaller maximal bending angle and a reduced gravitropic bending rate in comparison to the wild type. We therefore conclude that the crystals serve as statoliths for gravitropism in Phycomyces.

Crystallization↗

PubMed1999

Interferon-gamma rescues TNF-alpha-induced apoptosis mediated by up-regulation of TNFR2 on EoL-1 cells.

Recent studies show that apoptosis is important for the resolution of chronic inflammation. Using a human myeloblastic leukemia cell line, EoL-1, we investigated the effect of interferon-gamma (IFN-gamma), which differentiates EoL-1 into monocyte/macrophage-like cells on Fas antigen (Fas)- and tumor necrosis factor-alpha (TNF alpha)-induced apoptosis. Both TNF and anti-Fas monoclonal antibody (CH-11) induced apoptosis of EoL-1 cells. Pretreatment with IFN-gamma for 72 hours enhanced the CH-11-induced apoptosis with up-regulation of Fas. However, the treatment markedly inhibited the TNF-induced apoptosis. In flow cytometric analysis, EoL-1 expressed two types of tumor necrosis factor receptors (TNFR1 and TNFR2), and the expression of TNFR2 but not of TNFR1 was up-regulated significantly after the IFN-gamma treatment. The TNF-induced apoptosis was mimicked by a TNFR1 stimulating antibody (htr-9), and was reversed by a TNFR1 blocking antibody (H398). Although the TNFR1-mediated cytotoxic signal was not affected by IFN-gamma pretreatment, blocking TNFR2 by a specific antagonistic antibody (utr-1) canceled the inhibitory effect of IFN-gamma. In conclusion, TNF-induced apoptosis was mediated preferentially by TNFR1, and the anti-apoptotic effect of IFN-gamma was result from up-regulated TNFR2 in EoL-1 cell line. This cell line is a useful model to provide new insights into crosstalk among Fas/FasL-, TNF-, and IFN-gamma-mediated signaling.

Antibodies, Monoclonal↗

PubMed1999

Mechanism-based inactivation of cytochrome P450s 1A2 and 3A4 by dihydralazine in human liver microsomes.

Dihydralazine is known to induce immunoallergic hepatitis. Since anti-liver microsome (anti-LM) autoantibodies found in the serum of the patients react with P450 1A2, it is suggested that dihydralazine is biotransformed into a reactive metabolite, which covalently binds to cytochrome P450 1A2 and triggers an immunological response as a neoantigen. We investigated inactivation of P450 enzymes, including P450 1A2, during the metabolism of dihydralazine to evaluate the selectivity of P450 1A2 as a catalyst and a target of dihydralazine. Human liver microsomes or microsomes from lymphoblastoid cells expressing P450 enzymes were preincubated with dihydralazine in the presence of NADPH, followed by an assay of several monooxygenase activities. Preincubation of human liver microsomes with dihydralazine in the presence of NADPH resulted in decreases in phenacetin O-deethylase activity (an indicator of P450 1A2 activity) and testosterone 6beta-hydroxylase activity (P450 3A4), but not in diclofenac 4'-hydroxylase activity (P450 2C9), an indication of inactivation of P450s 1A2 and 3A4 during the dihydralazine metabolism. The inactivation of both of the P450s followed pseudo-first-order kinetics and was saturable with increasing dihydralazine concentrations. Similar time-dependent decreases in the activities were obtained in the case for use in microsomes expressing P450 1A2 and P450 3A4 instead of the human liver microsomes. The data presented here demonstrated that dihydralazine was metabolically activated not only by P450 1A2 but also by P450 3A4, and the chemically reactive metabolite bound to and inactivated the enzyme themselves, suggesting that dihydralazine is a mechanism-based inactivator of P450s 1A2 and 3A4. The data support the postulated covalent binding of a reactive metabolite of dihydralazine to P450 1A2 as a step in the formation of anti-LM antibodies in dihydralazine hepatitis, but it is not the unique factor for determining the specificity of the autoantibodies.

Antihypertensive Agents↗

PubMed1999

p38 MAP kinase regulates RANTES production by TNF-alpha-stimulated human pulmonary vascular endothelial cells.

BACKGROUND: RANTES plays an important role in the production of allergic inflammation of the airway through its chemotactic activity for eosinophils. However, the intracellular signal regulating RANTES expression in human pulmonary vascular endothelial cells has not been determined. In the present study, therefore, we examined the role of p38 mitogen-activated protein (MAP) kinase in RANTES production by tumor necrosis factor (TNF)-alpha-stimulated pulmonary vascular endothelial cells in order to clarify the signal transduction pathway regulating RANTES production by pulmonary vascular endothelial cells. METHODS: We examined p38 MAP kinase activation, and the effect of SB 203580, as the specific inhibitor for p38 MAP kinase, on p38 MAP kinase activity and RANTES production by TNF-alpha-stimulated human pulmonary vascular endothelial cells. RESULTS: The results showed that TNF-alpha induced RANTES production and p38 MAP kinase activity in human pulmonary vascular endothelial cells. Abrogation of p38 MAP kinase activity by SB 203580 repressed TNF-alpha-induced p38 MAP kinase activity and RANTES production. CONCLUSIONS: These results indicate that p38 MAP kinase plays an important role in the TNF-alpha-activated signaling pathway which regulates RANTES production by human pulmonary vascular endothelial cells.

Cells, Cultured↗

PubMed1999

Field trials of a rapid test for G6PD deficiency in combination with a rapid diagnosis of malaria.

A rapid single-step screening method for detection of glucose-6-phosphate dehydrogenase (G6 PD) deficiency was evaluated on Halmahera Island, Maluku Province, Indonesia, and in Shan and Mon States, Myanmar, in combination with a rapid diagnosis of malaria by an acridine orange staining method. Severe deficiency was detected by the rapid test in 45 of 1126 volunteers in Indonesia and 54 of 1079 in Myanmar, but it was difficult to distinguish blood samples with mild deficiency from those with normal activity. 89 of 99 severely deficient cases were later confirmed by formazan ring method in the laboratory, but 5 with mild and 5 with no deficiency were misdiagnosed as severe. Of the samples diagnosed as mild and no deficiency on-site, none was found to be severely deficient by the formazan method. Malaria patients were simultaenously++ detected on-site in 273 samples on Halmahera island and 277 samples from Shan and Mon States. In Mon State, primaquine was prescribed safely to G6 PD-normal malaria patients infected with Plasmodium vivax and/or gametocytes of P. falciparum. The new rapid test for G6 PD deficiency may be useful for detecting severe cases under field conditions, and both rapid tests combined are can be useful in malaria-endemic areas, facilitating early diagnosis, prompt and radical treatment of malaria and suppression of malaria transmission.

Acridine Orange↗

PubMed1999

Effects of nasal continuous positive airway pressure on pulmonary haemodynamics and tissue oxygenation in patients with obstructive sleep apnoea.

We investigated the acute effects of nasal continuous positive airway pressure (CPAP) on pulmonary haemodynamics and tissue oxygenation in eight men with obstructive sleep apnoea (OSA) by means of right heart catheterization. They were tested at four dosage levels of nasal CPAP: 0, 5, 10, and 15 cmH2O. Nasal CPAP significantly reduced the cardiac index at the 10 and 15 cmH2O doses. The mean pulmonary artery pressure was significantly elevated with 10 and 15 cmH2O, and pulmonary capillary wedge pressure was significantly increased with 15 cmH2O of nasal CPAP. Pulmonary vascular resistance was significantly increased with 10 cmH2O of nasal CPAP. The 5 cmH2O dose of nasal CPAP did not affect significantly these parameters. Mixed venous oxygen tension was unchanged at any pressure. We conclude that tissue oxygenation was maintained in the OSA patients during administration of nasal CPAP, even though a high CPAP clearly affected pulmonary haemodynamics.

Adult↗

PubMed1999

Multifocal peripheral bronchial carcinoid tumour.

Peripheral bronchial carcinoids sometimes arise as single solid or nodular lesions in the periphery of the lung. We encountered a 74-year-old Japanese male with bronchial carcinoids that were widely disseminated throughout the lung parenchyma. Pulmonary function tests revealed mild airflow obstruction. A metastatic process was ruled out from primary malignancy and a histological examination revealed findings consistent with a peripheral bronchial carcinoid. Based on these findings, we concluded that this patient had a primary multifocal peripheral bronchial carcinoid. An immunohistochemical examination revealed immunoreactivity for chromogranin A and bombesin. The present case appears to be an unusual case of diffuse multifocal peripheral bronchial carcinoid, confirmed by immunohistochemistry.

Aged↗

PubMed1999

New technique of leukocytapheresis by the use of nonwoven polyester fiber filter for inflammatory bowel disease.

Leukocytapheresis (LCAP) is widely used for the treatment of immunological diseases. We studied a new treatment of LCAP using a nonwoven polyester fiber filter. In a basic study, 30-70% of leukocytes were removed. Also, 30-68% of the leukocyte subsets were removed. Sixteen inflammatory bowel disease (IBD) patients, mainly with ulcerative colitis (UC), were treated by this method. Their cytokine activity was normalized in the filter and in the peripheral blood. Eleven of 12 patients with UC were induced to remission. Four patients with Crohn's disease (CD) exhibited improvement. The LCAP using a nonwoven polyester fiber filter was very efficient for treating the patients with IBD. Also, it will be a very useful treatment for immunological diseases and extracorporeal immunomodulation.

Adult↗

PubMed1999

Protective effect of aged garlic extract on the small intestinal damage of rats induced by methotrexate administration.

The methotrexate (MTX) administration to rats causes the damage of small intestine. The small intestinal damage was evaluated by measuring the intestinal permeability of the poorly absorbable compound, fluorescein isothiocyanate (FITC)-labeled dextran (average molecular weight, 4,400) (FD-4) using the in vitro everted intestine technique and by determining the FD-4 that appeared in plasma using the in situ closed loop intestine technique. The MTX administration to rats fed with the standard laboratory diet increased the small intestinal permeability of FD-4 due to the damage of the small intestine. Interestingly, the permeability of FD-4, when MTX was administered to rats fed with the aged garlic extract containing diet, was depressed almost to the level of control rats without the MTX treatment. The present study showed that the aged garlic extract protected the small intestine from the damage induced by the action of MTX on the crypt cells.

Animals↗

PubMed1999

Changes in intestinal absorption of 5-fluorouracil-treated rats.

5-Fluorouracil chemotherapy is often accompanied by gastrointestinal toxicity. In this study, we investigated the effect of 5-fluorouracil on the epithelial barrier function of rat small intestine by examining the absorption of a poorly absorbable marker, fluorescein isothiocyanate-labelled dextran (molecular weight 4,400). We further evaluated the intestinal absorption of 5-fluorouracil in rats treated orally with 5-fluorouracil once daily for 4 days. The small intestinal absorption of fluorescein isothiocyanate-labelled dextran and 5-fluorouracil was tested using in situ closed loop intestine technique and in vitro everted intestine technique, respectively. After administration of 5-fluorouracil to rats for 4 days, the body weight of rats decreased significantly and the fluorescein isothiocyanate-labelled dextran concentration in plasma increased significantly, compared with that of control rats to which the saline solution alone was administered. Moreover, the intestinal absorption of 5-fluorouracil in the 5-fluorouracil-treated rats was enhanced significantly, compared with that of control rats. The administration of 5-fluorouracil to rats caused body weight loss and epithelial barrier dysfunction of the small intestine in rats as shown by the increased permeation of the high molecular weight compound, fluorescein isothiocyanate-labelled dextran. The increased absorption of 5-fluorouracil after this treatment suggest that the 5-fluorouracil toxicity might be amplified by its treatment.

Animals↗

PubMed1999

Inhibitory effect of oestradiol on activation of rat hepatic stellate cells in vivo and in vitro.

BACKGROUND: Hepatic stellate cells play a key role in the pathogenesis of hepatic fibrosis. AIMS: To examine the inhibitory effect of oestradiol on stellate cell activation. METHODS: In vivo, hepatic fibrosis was induced in rats by dimethylnitrosamine or pig serum. In vitro, rat stellate cells were activated by contact with plastic dishes resulting in their transformation into myofibroblast-like cells. RESULTS: In the dimethylnitrosamine and pig serum models, treatment with oestradiol at gestation related doses resulted in a dose dependent suppression of hepatic fibrosis with restored content of hepatic retinyl palmitate, reduced collagen content, lower areas of stellate cells which express alpha smooth muscle actin (alpha-SMA) and desmin, and lower procollagen type I and III mRNA levels in the liver. In cultured stellate cells, oestradiol inhibited type I collagen production, alpha-SMA expression, and cell proliferation. These findings suggest that oestradiol is a potent inhibitor of stellate cell transformation. CONCLUSION: The antifibrogenic role of oestradiol in the liver may contribute to the sex associated differences in the progression from hepatic fibrosis to cirrhosis

Animals↗

PubMed1999

Hyperosmolarity-induced interleukin-8 expression in human bronchial epithelial cells through p38 mitogen-activated protein kinase.

The changes in airway osmolarity have been described to contribute to the production of exercise- induced bronchoconstriction (EIB) and the development of the late-phase response (LPR). The mechanism has been investigated; however, the responsiveness of bronchial epithelial cells (BEC) to hyperosmolarity and the intracellular signals leading to cell activation have not been determined. In this study, we examined the effect of hyperosmolar medium on interleukin-8 (IL-8) expression and the role of p38 mitogen-activated protein (MAP) kinase and c-Jun NH2 terminal kinase ( JNK) in human BEC in this response in order to clarify the intracellular signals regulating IL-8 expression in hyperosmolarity-stimulated BEC. The results showed that hyperosmolarity induced IL-8 expression in a concentration dependent manner, p38 MAP kinase phosphorylation and activation, and JNK activation whether NaCl or mannitol was used as the solute. SB 203580 as the specific p38 MAP kinase inhibitor inhibited hyperosmolarity-induced p38 MAP kinase activation and partially inhibited hyperosmolarity-induced IL-8 expression. These results indicate that p38 MAP kinase, at least in part, regulates hyperosmolarity-induced IL-8 expression in BEC. However, other signals such as JNK are possibly also involved. These results provide new evidence on the mechanism responsible for the development of the LPR induced by EIB, and a strategy for treatment with the specific p38 MAP kinase inhibitor.

Blotting, Northern↗

PubMed1999

Relaxation of contracted rabbit tracheal and human bronchial smooth muscle by Y-27632 through inhibition of Ca2+ sensitization.

The mechanism of Ca2+ sensitization of contraction has not been elucidated in airway smooth muscle (SM). To determine the role of a small G protein, rhoA p21, and its target protein, rho-associated coiled coil-forming protein kinase (ROCK), in receptor-coupled Ca2+ sensitization of airway SM, we studied the effect of (+)-(R)-trans-4-(1-aminoethyl)-N-(4-pyridyl)cyclohexane carboxamide dihydrochloride, monohydrate (Y-27632), a ROCK inhibitor, on isometric contractions in rabbit tracheal and human bronchial SM. Y-27632 completely reversed 1 microM carbachol (CCh)-induced contraction of intact trachea with a concentration producing half-maximum inhibition of effect (IC50) of 1.29 +/- 0.2 microM (n = 5). Although 4beta-phorbol 12,13-dibutyrate (1 microM)-induced Ca2+ sensitization was relatively resistant to Y-27632 in alpha-toxin-permeabilized trachea, CCh (100 microM) plus guanosine triphosphate (GTP) (3 microM)- and guanosine 5'-O-(3'-thiotriphosphate) (10 microM)-induced contractions were relaxed completely by Y-27632 with IC50 of 1.44 +/- 0.3 (n = 6) and 1.15 +/- 0.3 microM (n = 6). Endothelin-1 (1 microM) plus GTP (3 microM)- developed force was also reversed by Y-27632 with IC50 of 4. 10 +/- 1.1 microM (n = 6) in the alpha-toxin-permeabilized bronchus. Both the rabbit and human SM expressed rhoA p21, ROCK I, and its isoform ROCK II. Collectively, rho/ROCK-mediated Ca2+ sensitization plays a central role in the sustained phase of airway SM contraction, and selective inhibition of this pathway may become a new strategy to resolve airflow limitation in asthma.

1-Methyl-3-isobutylxanthine↗

PubMed1999

In vivo and in vitro trimethadione oxidation activity of the liver from various animal species including mouse, hamster, rat, rabbit, dog, monkey and human.

Trimethadione (TMO) has the properties required of a probe drug for the evaluation of hepatic drug-oxidizing capacity and, in this study, we have summarized the in vivo and in vitro metabolism of TMO in various animal species including mouse, hamster, rat, rabbit, dog, monkey and human. In the in vivo study, the plasma TMO level was measured after intravenous or oral (human) administration of TMO at a dose of 4 mg/kg to various animal species. The rate of TMO metabolic clearance in these animal species in vivo was in the order mouse > hamster > rat > rabbit > dog > monkey > human. In the in vitro study, species differences were observed in the cytochrome P450 (P450) content and drug-oxidizing enzyme activity. The content of P450 was monkey> mouse > dog > rabbit > hamster > rat > human. On the other hand, TMO N-demethylation was in the order mouse > hamster > rat > rabbit > dog > monkey > human. There was a good correlation between the mean total body clearance of TMO (in vivo) and the mean TMO N-demethylase activity (in vitro) (y=1.7 x +0.11, r=0.965, P < 0.001). These results show that TMO is a probe agent with metabolic and pharmacokinetic characteristics making it attractive for the in vivo and in vitro characterization of metabolic activity in various animal species.

Animals↗

PubMed1999

Biphasic kinetics of imipramine N-oxidation in rat brain microsomes.

Imipramine (IMI) N-oxidase activity in brain microsomes from rats of both sexes was determined by high performance liquid chromatography, and compared with the results in rat liver microsomes. Brain and liver microsomal IMI N-oxidation was sensitive to thermal inactivation and had an optimal pH at around 9.0. IMI N-oxidase activity (15.54 pmol/min/mg protein) in brain microsomes was about one-hundredth that of liver microsomes (2.08 nmol/min/mg protein) at a substrate concentration of 5 mM. IMI N-oxidase activities in both brain and liver microsomes displayed biphasic kinetics that associated a low Km-low Vmax element with a high Km-high Vmax component. Furthermore, a significant sex difference was observed in Vmax values (male>female) in both phases, but Km values were similar between male and female rats, resulting in a significant sex difference (male>female) in intrinsic clearance values (Vmax/Km) of the low-Km and the high-Km phases.

Animals↗

PubMed1999

Contribution of flavin-containing monooxygenase and cytochrome P450 to imipramine N-oxidation in rat hepatic microsomes.

Enzymatic formation of desipramine (DMI) and imipramine N-oxide (IMINO) was kinetically characterized in rat liver microsomes at pH 8.5 and 7.5. The formation of IMINO was quickly suppressed by the preincubation of microsomes at 37 degrees C at pH 8.5, but the suppression was comparatively gentle at pH 7.5. In kinetic studies, the formation of DMI was monophasic at the two pH points, and a substrate inhibition was observed at pH 8.5, but not at pH 7.5. In contrast, the formation of IMINO was biphasic at both pH points, Le., the summation of a low-Km phase and a high-Km phase. Methimazole (MZ), an inhibitor of flavin-containing monooxygenase (FMO), markedly suppressed the low-Km phase of IMINO formation at both pH points. MZ also suppressed DMI formation at pH 8.5, but it elevated DMI formation at pH 7.5. SKF 525-A, an inhibitor of cytochrome P450 (CYP), markedly suppressed DMI formation at both pH points. The inhibitor suppressed IMINO formation in the high-Km phase of the biphasic kinetics at both pH points, whereas it stimulated the activity of the low-Km phase at pH 7.5. These results suggest that CYP enzyme(s) are mainly responsible for DMI formation at pH 8.5 and 7.5, and FMO enzyme(s) also are involved in IMI N-demethylation at a higher pH range in rat liver microsomes, at least in part. In the formation of IMINO, FMO is a major enzyme at both pH points, and CYP may also contribute to the N-oxide formation to some extent at pH 8.5.

Animals↗