T Nakazawa

Gunma University, Maebashi, Gunma, Japan

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Publications (106)194.83 Total impact

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    ABSTRACT: The antituberculous drug isoniazid (INH) is acetylated by N-acetyltransferase 2 (NAT2), and the frequency of INH-induced hepatotoxicity is determined by the NAT2 genotype. NAT2 genotyping is not done routinely in hospital laboratories because of its difficulty. Use of microarrays for research is becoming common and its expectations of clinical application are increasing. In this study, we attempted to develop an easier method of NAT2 genotyping for clinical use. We devised a novel oligonucleotide-based DNA microarray for NAT2 genotyping using a recently developed technique for attaching oligonucleotide probes to poly carbodiimide-coated glass slides, which achieves a stronger hybridization signal and better specificity than the more widely used aminosilane-coated slides. To assess the validity of this microarray, four clones with NAT2 mutations and DNA from 42 tuberculosis patients were investigated by the microarray method and by restriction fragment length polymorphism analysis. The results of genotyping by these two methods were in agreement. Analysis of the relationship between the NAT2 phenotype determined by the DNA microarray and the risk of INH-induced hepatotoxicity revealed that slow acetylators had a significantly higher risk. These findings suggest that our microarray may be clinically useful for predicting drug reactions to INH.
    Tuberculosis 10/2006; 86(5):374-81. DOI:10.1016/j.tube.2005.09.002 · 3.50 Impact Factor
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    ABSTRACT: The Adacolumn is an adsorptive-type extracorporeal device, which is filled with cellulose diacetate beads that selectively adsorb granulocytes and monocytes. Patients with severe persistent asthma experience highly variable continuous symptoms and severe exacerbations in spite of medication based on inhaled glucocorticosteroids. Granulocyte and monocyte adsorption apheresis using extracorporeal circulation through the Adacolumn was performed in nine patients with severe persistent asthma. The extracorporeal circulation through the Adacolumn was performed once a week for 5 weeks. We were able to perform this therapy without any severe adverse effects in all patients, although one patient complained of general fatigue just after the circulations. In six of the nine patients, the increase in peak expiratory flow (PEF) was more than 50 mL/min. The average increase in morning PEF was 23.3% while that in the evening PEF was 26.4% after the therapy. This therapy was not harmful for patients with severe persistent asthma. A placebo-controlled study will be desired to evaluate the efficacy of this nonpharmacological strategy accurately.
    Inflammation 03/2005; 29(1):9-16. DOI:10.1007/s10753-006-8963-5 · 2.21 Impact Factor
  • Tsugio Nakazawa
    Arerugī = [Allergy] 12/2004; 53(11):1112-8.
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    ABSTRACT: To clarify whether cyclic AMP (cAMP)/cAMP-dependent protein kinase (PKA) activation and Rho-kinase inhibition share a common mechanism to decrease the Ca2+ sensitivity of airway smooth muscle contraction, we examined the effects of 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP), a stable cAMP analog, and (+)-(R)-trans-4-(1-aminoethyl)-N-(4-pyridyl) cyclohexane carboxamide dihydrochloride, monohydrate (Y-27632), a Rho-kinase inhibitor, on carbachol (CCh)-, guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS)-, 4beta-phorbol 12,13-dibutyrate (PDBu)-, and leukotriene D4 (LTD4)-induced Ca2+ sensitization in alpha-toxin-permeabilized rabbit tracheal and human bronchial smooth muscle. In rabbit trachea, CCh-induced smooth muscle contraction was inhibited by 8-BrcAMP and Y-27632 to a similar extent. However, GTPgammaS-induced smooth muscle contraction was resistant to 8-BrcAMP. In the presence of a saturating concentration of Y-27632, PDBu-induced smooth muscle contraction was completely reversed by 8-BrcAMP. Conversely, PDBu-induced smooth muscle contraction was resistant to Y-27632. In the presence of a saturating concentration of 8-BrcAMP, GTPgammaS-induced Ca2+ sensitization was also reversed by Y-27632. The 8-BrcAMP had no effect on the ATP-triggered contraction of tracheal smooth muscle that had been treated with calyculin A in rigor solutions. The 8-BrcAMP and Y-27632 additively accelerated the relaxation rate of PDBu- and GTPgammaS-treated smooth muscle under myosin light chain kinase-inhibited conditions. In human bronchus, LTD4-induced smooth muscle contraction was inhibited by both 8-BrcAMP and Y-27632. We conclude that cAMP/PKA-induced Ca2+ desensitization contains at least two mechanisms: 1) inhibition of the muscarinic receptor signaling upstream from Rho activation and 2) cAMP/PKA's preferential reversal of PKC-mediated Ca2+ sensitization in airway smooth muscle.
    AJP Lung Cellular and Molecular Physiology 11/2004; 287(4):L641-8. DOI:10.1152/ajplung.00287.2003 · 4.04 Impact Factor
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    ABSTRACT: • To examine the contributions of the putative Ca2+ releasers, inositol 1,4,5-trisphosphate (InsP3), cyclic ADP ribose (cADPR), and nicotinate adenine dinucleotide phosphate (NAADP), to carbachol (CCh)-induced contraction in airway smooth muscle, we measured force development of permeabilized rabbit tracheal smooth muscle, human bronchial smooth muscle and guinea-pig ileum longitudinal smooth muscle. • In the presence of 50 mGTP, CCh and InsP3 contracted α-toxin-permeabilized tracheal smooth muscle dose dependently; the EC50 values for CCh and InsP3 were 1.84 mand 363 m, and the maximum responses (normalized to the 30 mM caffeine response) to 100 mCCh and to 800 mInsP3 were 206 ± 13.4 % (mean ± s.e.m.) and 84.4 ± 5.3 %, respectively. • However, cADPR (10-300 m), -NAD+ (2.5 mM), FK506 (30 m) and NAADP (100 m) neither contracted the strip by themselves nor affected the subsequent CCh (1 m) response. α-Toxin-permeabilized bronchial smooth muscle and ileum smooth muscle also responded to caffeine, InsP3 and CCh but not to cADPR. • Both 100 m8-amino-cADPR, a selective cADPR antagonist, and 100 mthionicotinamide-NADP, a selective NAADP antagonist, failed to inhibit the CCh response, although procaine abolished the caffeine, InsP3 and CCh responses in the permeabilized tracheal smooth muscle. • Although inhibition of the caffeine response by 30 mryanodine was nearly complete, approximately 30 % of the InsP3 (300 m) plus GTP (50 m) response was retained, and the resultant response disappeared after the caffeine response was evoked in the presence of ryanodine. • Heparin (300 g ml−1) blocked InsP3 (300 m) and CCh (3 m) responses in -escin-permeabilized tracheal smooth muscle, while Ruthenium Red (100 m) partially inhibited the CCh response. • Collectively, InsP3 but not cADPR or NAADP plays a key role in CCh-initiated contraction, and InsP3 utilizes a single compartment of the caffeine/ryanodine-sensitive stored Ca2+ in airway smooth muscle.
    The Journal of Physiology 09/2004; 511(3):915 - 933. DOI:10.1111/j.1469-7793.1998.915bg.x · 4.54 Impact Factor
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    Tsugio Nakazawa · Kunio Dobashi
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    ABSTRACT: Recent asthma deaths were examined from yearly reports of the Ministry of Health, Labor and Welfare of Japan and from reports published by the Japan Asthma Death Investigation Committee on 811 deaths over the period 1992−2000. The rate and number of recent asthma deaths in Japan have been decreasing rapidly. Most asthma deaths were of patients aged 70−90 years and there has been a marked trend for increased asthma deaths in the elderly. As for the circumstances surrounding the deaths, sudden death, unstable sudden aggravation and intermittent aggravation were mainly noted. Respiratory infections, fatigue and stress were the major courses of fatal attacks contributing to deaths due to asthma. Many of the patients who died from asthma had been diagnosed as having as moderate to severe asthma and many had non-atopic asthma. There are some reports that suggest that the recent decrease in asthma deaths in Japan is correlated with the use of inhaled corticosteroids.
    Allergology International 08/2004; 53(3):205 - 209. DOI:10.1111/j.1440-1592.2004.00334.x
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    ABSTRACT: Previously we have reported that Y-27632, a selective inhibitor of Rho-associated protein kinases (ROCKs) for RhoA, suppressed concanavalin A (Con A)-induced secretion of cytokines from peripheral T cells of normal persons. Recent studies suggested its usefulness for clinical management of bronchial asthma. We examined effect of Y-27632 on release of cytokines from T cells of asthmatic patients. Peripheral T cells of six asthmatic subjects and six normal persons were stimulated with Con A for 24 h in the presence of Y-27632. The concentrations of IL-2, interferon (IFN)-gamma, IL-4, and IL-5 in supernatant were measured. Y-27632 down-regulated secretion of IL-2 and IFN-gamma and weakly decreased secretion of IL-4 and IL-5 from Con A-activated T cells in the asthmatics. The reduced secretion of IFN-gamma and IL-4 in the asthmatics was inferior to that in the normal subjects. Our data suggested that the involvement of RhoA/ROCK pathway in TCR-mediated secretion of IFN-gamma and IL-4 in patients with bronchial asthma differed from that in healthy persons.
    International Immunopharmacology 05/2004; 4(4):557-61. DOI:10.1016/j.intimp.2003.12.014 · 2.71 Impact Factor
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    ABSTRACT: Y-27632 selectively inhibits Rho-associated protein kinases (ROCKs), an effector for RhoA. The RhoA system is involved in T cell activation. Y-27632 mimicked effects of beta agonists on human cells. We examined the effects of both Y-27632 and Isoproterenol (Iso) on the release of T helper type 1 (Th-1) cytokines (interleukin (IL)-2 and interferon (IFN)-gamma) and Th-2 cytokines (IL-4 and IL-5) from activated human T cells. Peripheral T cells obtained from seven healthy volunteers were incubated in the presence of Y-27632 (0.1-10 micro M) for 30 min, and stimulated with 50 micro g/ml of Concanavalin A (Con A) for 24 h. Concomitantly, after an incubation with medium alone, cells were stimulated with Con A in the presence of Iso (0.1-10 micro M). The concentration of these cytokines in supernatants was measured by ELISA. Both Y-27632 and Iso suppressed release of Th-1 cytokines, decreased release of Th-2 cytokines weakly, and reduced ratio of Th-1/Th-2 cytokine release from Con A-activated T cells. These inhibitory effects of Y-27632 closely resembled those of Iso at each concentration tested. Y-27632 mimicked effects of Iso on secretion of Th-1 and Th-2 cytokines from human peripheral T cells activated with Con A. It is suggested that the RhoA/ROCK system plays an important role in the release of Th-1 cytokines and is partially involved in the release of Th-2 cytokines from human T cells activated through T cell receptor (TCR).
    International Immunopharmacology 12/2003; 3(12):1619-25. DOI:10.1016/S1567-5769(03)00184-X · 2.71 Impact Factor
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    ABSTRACT: Although c-Jun N-terminal kinase (JNK) plays an important role in cytokine expression, its function in IL-12 production is obscure. The present study uses human macrophages to examine whether the JNK pathway is required for LPS-induced IL-12 production and defines how JNK is involved in the regulation of IL-12 production by glutathione redox, which is the balance between intracellular reduced (GSH) and oxidized glutathione (GSSG). We found that LPS induced IL-12 p40 protein and mRNA in a time- and concentration-dependent manner in PMA-treated THP-1 macrophages, and that LPS activated JNK and p38 mitogen-activated protein (MAP) kinase, but not extracellular signal-regulated kinase, in PMA-treated THP-1 cells. Inhibition of p38 MAP kinase activation using SB203580 dose dependently repressed LPS-induced IL-12 p40 production, as described. Conversely, inhibition of JNK activation using SP600125 dose dependently enhanced both LPS-induced IL-12 p40 production from THP-1 cells and p70 production from human monocytes. Furthermore, JNK antisense oligonucleotides attenuated cellular levels of JNK protein and LPS-induced JNK activation, but augmented IL-12 p40 protein production and mRNA expression. Finally, the increase in the ratio of GSH/GSSG induced by glutathione reduced form ethyl ester (GSH-OEt) dose dependently enhanced LPS-induced IL-12 p40 production in PMA-treated THP-1 cells. GSH-OEt augmented p38 MAP kinase activation, but suppressed the JNK activation induced by LPS. Our findings indicate that JNK negatively affects LPS-induced IL-12 production from human macrophages, and that glutathione redox regulates LPS-induced IL-12 production through the opposite control of JNK and p38 MAP kinase activation.
    The Journal of Immunology 08/2003; 171(2):628-35. DOI:10.4049/jimmunol.171.2.628 · 5.36 Impact Factor
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    ABSTRACT: Many of the fibrogenic effects of transforming growth factor-beta (TGF-beta) might be mediated by connective tissue growth factor (CTGF). The present study investigates the role of mitogen-activated protein (MAP) kinase in the expression of CTGF mRNA in the human lung fibroblast line, HFL-1. TGF-beta1 enhanced CTGF mRNA levels in a time- and concentration-dependent manner, and this enhancement was also dependent upon transcription. Inhibition of p38 MAP kinase or extracellular signal-regulated kinase (ERK) activation did not affect TGF-beta1-induced CTGF expression. On the other hand, specific inhibitors of phosphatidylinositol 3-kinase (PI3K) suppressed TGF-beta1-induced CTGF expression in a concentration-dependent manner. TGF-beta1 activated c-Jun NH2-terminal kinase (JNK) and p38 MAP kinase, but not ERK in HFL-1 cells. PI3K inhibitors dose-dependently suppressed TGF-beta1-induced JNK, but not p38 MAP kinase activation. Finally, JNK1 and JNK2 antisense oligonucleotides attenuated cellular levels of JNK1 and JNK2 protein, respectively, and repressed TGF-beta1-induced CTGF expression. These results suggest that TGF-beta1-induced CTGF mRNA expression is mediated through the JNK-dependent pathway, whereas p38 MAP kinase and ERK pathways minimally contribute.
    American Journal of Respiratory Cell and Molecular Biology 07/2003; 28(6):754-61. DOI:10.1165/rcmb.4892 · 4.11 Impact Factor
  • The Kitakanto Medical Journal 01/2003; 53(3):257-262. DOI:10.2974/kmj.53.257
  • The Kitakanto Medical Journal 01/2003; 53(2):185-189. DOI:10.2974/kmj.53.185
  • The Kitakanto Medical Journal 01/2003; 53(3):251-255. DOI:10.2974/kmj.53.251
  • The Kitakanto Medical Journal 01/2003; 53(3):285-287. DOI:10.2974/kmj.53.285
  • The Kitakanto Medical Journal 01/2003; 53(3):289-291. DOI:10.2974/kmj.53.289
  • The Kitakanto Medical Journal 01/2003; 53(2):191-194. DOI:10.2974/kmj.53.191
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    ABSTRACT: To evaluate osteoporosis in asthmatic patients. Bone mineral density (BMD) was measured using three different methods, namely computed X-ray densitometry (CXD), digital image processing (DIP), and dual energy X-ray absorptiometry (DXA). The BMD data were standardized using the sex- and age-matched mean value of BMD. One hundred and twenty-eight patients with persistent asthma. The standardized BMD expressed as Z-score in asthmatic patients was significantly lower than the norm (Z-score -0.48 +/- 1.17, mean +/- SD). In patients who had been continuously treated with oral corticosteroids (OCS), the standardized BMD was significantly lower than that in patients treated without OCS. In addition, the standardized BMD in patients 60 years and over (Z-score -0.71 +/- 1.10, mean +/- SD, n = 58) had decreased to a greater extent than the decrease seen in patients under 60 years (Z-score -0.30 +/- 1.21, n=70). Moreover, BMD in these older patients decreased after a 6-month treatment protocol involving the use of an inhaled corticosteroid, fluticasone propionate (FP). During the 6 months, the treatment did not affect BMD in patients who were receiving FP for the first time. Although the BMD did not decrease in patients treated with FP without OCS, the BMD in patients treated with both FP and OCS decreased during the 6 months. These results indicate that the continuous administration of OCS in patients with severe persistent asthma, particularly in older patients, may affect BMD in the short term even at a low OCS dose.
    Internal Medicine 11/2002; 41(10):798-804. DOI:10.2169/internalmedicine.41.798 · 0.97 Impact Factor
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    ABSTRACT: Human Toll-like receptor 4 (TLR4) has recently been identified, and it has been shown to be the main protein involved in recognizing gram-negative bacteria. We examined the regulation of TLR4 surface expression in human peripheral blood monocytes and B cells by interleukin-2 (IL-2) and IL-4. IL-2 up-regulated TLR4 surface expression on human peripheral blood monocytes, but did not change expression on human peripheral B cells. By contrast, IL-4 down-regulated TLR4 surface expression on human peripheral blood monocytes, but up-regulated TLR4 surface expression on human peripheral B cells. These results indicate that Th1 cytokine IL-2 enhances receptors involved in the response to gram-negative bacteria and that activation of cellular immunity may enhance defense against these pathogens through monocytes, but not B cells, whereas Th2 cytokine IL-4 modulates the receptor response to gram-negative bacteria and that activation of humoral immunity may enhance defense against these pathogens through B cells, but not monocytes.
    Immunology Letters 05/2002; 81(1):71-5. DOI:10.1016/S0165-2478(01)00328-5 · 2.37 Impact Factor
  • Y Mita · K Dobashi · Y Shimizu · T Nakazawa · M Mori
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    ABSTRACT: Human Toll-like receptor 4 (TLR4) has recently been identified and has been shown to be the main protein involved in recognizing Gram-negative bacteria. We examined the regulation of TLR4 surface expression in a human monocytic cell line (THP-1 cells) by two traditional Chinese herbal medicines. Bu-Zhong-Yi-Qi-Tang (TJ-41) and Shi-Quan-Da-Bu-Tang (TJ-48). TJ-41 and TJ-48 upregulated TLR4 surface expression in THP-1 cells, as well as enhanced TLR4 surface expression in these cells both dose- and time-dependently. These findings suggest that TJ-41 and TJ-48 increase the receptor involved in the response to Gram-negative bacteria and may enhance defenses against these pathogens.
    Methods and Findings in Experimental and Clinical Pharmacology 04/2002; 24(2):67-70. DOI:10.1358/mf.2002.24.2.677128 · 0.77 Impact Factor
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    ABSTRACT: We examined whether changes in intracellular reduced (GSH) or oxidized (GSSG) glutathione of human monocytes regulate lipopolysaccharide (LPS)-induced IL-12 production and defined the molecular mechanism that underlies glutathione redox regulation. Monocytes exposed to glutathione reduced form ethyl ester (GSH-OEt) or maleic acid diethyl ester (DEM) increased or decreased the intracellular GSH/GSSG ratio, respectively. LPS-induced IL-12 production and p38 mitogen-activated protein (MAP) kinase activation were enhanced by GSH-OEt but suppressed by DEM. Selective p38 inhibitors showed that p38 promoted GSH-OEt-enhanced IL-12 production. Furthermore, IFN-gamma priming increased the GSH/GSSG ratio and enhanced IL-12 production through p38, and DEM negated the priming effect of IFN-gamma on p38 activation and IL-12 production as well as on the GSH/GSSG ratio. These findings reveal that glutathione redox regulates LPS-induced IL-12 production from monocytes through p38 MAP kinase activation and that the priming effect of IFN-gamma on IL-12 production is partly a result of the glutathione redox balance.
    Journal of Leukocyte Biology 03/2002; 71(2):339-47. · 4.30 Impact Factor