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Yoshihiro Mitani,
Keizo Sato,
Yosuke Muramoto,
Tomohiro Karakawa,
Masataka Kitamado,
Tatsuya Iwanaga,
Tetsuji Nabeshima,
Kumiko Maruyama,
Kazuko Nakagawa,
Kazuhiko Ishida, Kazumi Sasamoto
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ABSTRACT: Pirfenidone (PFD) is focused on a new anti-fibrotic drug, which can minimize lung fibrosis etc. We evaluated the superoxide (O2*-) scavenging activities of PFD and the PFD-iron complex by electron spin resonance (ESR) spectroscopy, luminol-dependent chemiluminescence assay, and cytochrome c reduction assay. Firstly, we confirmed that the PFD-iron complex was formed by mixing iron chloride with threefold molar PFD, and the complex was stable in distilled water and ethanol. Secondary, the PFD-iron complex reduced the amount of O2*- produced by xanthine oxidase/hypoxanthine without inhibiting the enzyme activity. Thirdly, it also reduced the amount of O2*- released from phorbor ester-stimulated human neutrophils. PFD alone showed few such effects. These results suggest the possibility that the O2*- scavenging effect of the PFD-iron complex contributes to the anti-fibrotic action of PFD used for treating idiopathic pulmonary fibrosis.
Biochemical and Biophysical Research Communications 08/2008; 372(1):19-23. · 2.48 Impact Factor
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Tomohiro Karakawa,
Keizo Sato,
Yosuke Muramoto,
Yoshihiro Mitani,
Masataka Kitamado,
Tatsuya Iwanaga,
Tetsuji Nabeshima,
Kumiko Maruyama,
Kazuko Nakagawa,
Kazuhiko Ishida, Kazumi Sasamoto
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ABSTRACT: Electron spin resonance using spin-trapping is a useful technique for detecting direct reactive oxygen species, such as superoxide (O2.-). However, the widely used spin trap 2,2-dimethyl-3,4-dihydro-2H-pyrrole N-oxide (DMPO) has several fundamental limitations in terms of half-life and stability. Recently, the new spin trap 2-diphenylphosphinoyl-2-methyl-3,4-dihydro-2H-pyrrole N-oxide (DPhPMPO) was developed by us. We evaluated the biological applicability of DPhPMPO to analyze O2.- in both cell-free and cellular systems. DPhPMPO had a larger rate constant for O2.- and formed more stable spin adducts for O2.- than DMPO in the xanthine/xanthine oxidase (X/XO) system. In the phorbol myristate acetate-activated neutrophil system, the detection potential of DPhPMPO for O2.- was significantly higher than that of DMPO (k(DMPO)=13.95M(-1)s(-1), k(DPhPMPO)=42.4M(-1)s(-1)). These results indicated that DPhPMPO is a potentially good candidate for trapping O2.- in a biological system.
Biochemical and Biophysical Research Communications 06/2008; 370(1):93-7. · 2.48 Impact Factor
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Tomohiro Karakawa,
Keizo Sato,
Yosuke Muramoto,
Yoshihiro Mitani,
Masataka Kitamado,
Tatsuya Iwanaga,
Tetsuji Nabeshima, Kumiko Maruyama,
Kazuko Nakagawa,
Kazuhiko Ishida, Kazumi Sasamoto
[show abstract]
[hide abstract]
ABSTRACT: Electron spin resonance using spin-trapping is a useful technique for detecting direct reactive oxygen species, such as superoxide (O2·-). However, the widely used spin trap 2,2-dimethyl-3,4-dihydro-2H-pyrrole N-oxide (DMPO) has several fundamental limitations in terms of half-life and stability. Recently, the new spin trap 2-diphenylphosphinoyl-2-methyl-3,4-dihydro-2H-pyrrole N-oxide (DPhPMPO) was developed by us. We evaluated the biological applicability of DPhPMPO to analyze O2·- in both cell-free and cellular systems. DPhPMPO had a larger rate constant for O2·- and formed more stable spin adducts for O2·- than DMPO in the xanthine/xanthine oxidase (X/XO) system. In the phorbol myristate acetate-activated neutrophil system, the detection potential of DPhPMPO for O2·- was significantly higher than that of DMPO (kDMPO=13.95M−1s−1, kDPhPMPO=42.4M−1s−1). These results indicated that DPhPMPO is a potentially good candidate for trapping O2·- in a biological system.
Biochemical and Biophysical Research Communications - BIOCHEM BIOPHYS RES COMMUN. 01/2008; 370(1):93-97.
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ABSTRACT: Formation of senile plaques composed of amyloid beta peptide, a pathological hallmark of Alzheimer disease, in human brains precedes disease onset by many years. Noninvasive detection of such plaques could be critical in presymptomatic diagnosis and could contribute to early preventive treatment strategies. Using amyloid precursor protein (APP) transgenic mice as a model of amyloid beta amyloidosis, we demonstrate here that an intravenously administered (19)F-containing amyloidophilic compound labels brain plaques and allows them to be visualized in living mice by magnetic resonance imaging (MRI) using (19)F and (1)H. Our findings provide a new direction for specific noninvasive amyloid imaging without the danger of exposure to radiation. This approach could be used in longitudinal studies in mouse models of Alzheimer disease to search for biomarkers associated with amyloid beta pathology as well as to track disease course after treatment with candidate medications.
Nature Neuroscience 05/2005; 8(4):527-33. · 15.53 Impact Factor
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ABSTRACT: Formation of senile plaques composed of amyloid peptide, a pathological hallmark of Alzheimer disease, in human brains precedes disease onset by many years. Noninvasive detection of such plaques could be critical in presymptomatic diagnosis and could contribute to early preventive treatment strategies. Using amyloid precursor protein (APP) transgenic mice as a model of amyloid amyloidosis, we demonstrate here that an intravenously administered 19F-containing amyloidophilic compound labels brain plaques and allows them to be visualized in living mice by magnetic resonance imaging (MRI) using 19F and 1H. Our findings provide a new direction for specific noninvasive amyloid imaging without the danger of exposure to radiation. This approach could be used in longitudinal studies in mouse models of Alzheimer disease to search for biomarkers associated with amyloid pathology as well as to track disease course after treatment with candidate medications.
Nature Neuroscience 03/2005; 8(4):527-533. · 15.53 Impact Factor
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ABSTRACT: Two styrylbenzene derivatives, (E,E)-1-fluoro-2,5-bis-(3-hydroxycarbonyl-4-hydroxy)styrylbenzene (FSB) and (E,E)-1-bromo-2,5-bis(3-hydroxycarbonyl-4-hydroxy)styrylbenzene-alpha,alpha'-(13)C(2) ([(13)C]BSB), were synthesized for use as a histochemical stain to detect amyloid plaques of Alzheimer's disease (AD) brain sections. An analysis of fluorescence spectra demonstrated that FSB shows approximately twofold fluorescence intensity relative to the conventional styrylbenzene derivative, (E,E)-1-bromo-2,5-bis-(3-hydroxycarbonyl-4-hydroxy)styrylbenzene (BSB). Moreover, FSB was found to stain amyloid plaques and neurofibrillary tangles of AD brains with greater fluorescence intensity and a lower level of background signals compared to BSB. These finding indicate that FSB can be an excellent fluorescent compound to label human amyloid lesions with high sensitivity and specificity. Because of the possession of a nuclide with a quantized angular momentum, both FSB and [(13)C]BSB are also potential contrast agents for magnetic resonance imaging to locate AD pathologies in vivo.
European Journal of Medicinal Chemistry 08/2004; 39(7):573-8. · 3.35 Impact Factor
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Yukio Ando,
Katsuki Haraoka,
Hisayasu Terazaki,
Yutaka Tanoue,
Kensuke Ishikawa,
Shoichi Katsuragi,
Masaaki Nakamura,
Xuguo Sun,
Kazuko Nakagawa, Kazumi Sasamoto,
Kazuhiro Takesako,
Takashi Ishizaki,
Yutaka Sasaki,
Katsumi Doh-ura
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ABSTRACT: We synthesized (trans,trans)-1-bromo-2,5-bis-(3-hydroxycarbonyl-4-hydroxy)styrylbenzene (BSB) and used this compound to detect amyloid fibrils in autopsy and biopsy samples from patients with localized amyloidosis, such as familial prion disease, and systemic amyloidosis, such as familial amyloidotic polyneuropathy, amyloid A (AA) amyloidosis, light chain (AL) amyloidosis, and dialysis-related amyloidosis. BSB showed reactions in all Congo red-positive and immunoreactive regions of the samples examined in the study, and some amyloid fibrils in the tissues could be detected more precisely with BSB than with the other methods. In the mouse model of AA amyloidosis, injected BSB reacted with amyloid in all regions in the serial sections in which Congo red staining was positive. A highly sensitive 27-MHz quartz crystal microbalance analysis revealed that BSB showed a significant affinity for amyloid fibrils purified from familial amyloidotic polyneuropathy and dialysis-related amyloidosis samples and suppressed formation of transthyretin amyloid in vitro. These results suggest that BSB may become a valuable tool for detection of amyloid deposits in amyloidosis and of the mechanism of amyloid formation.
Laboratory Investigation 01/2004; 83(12):1751-9. · 3.64 Impact Factor
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ABSTRACT: A novel compound, N,N'-bis(2,4-di-sulfobenzyl)tolidine tetrasodium salt (SBT), was synthesized for use as a chromogenic indicator for oxidizing substances, and its applicability to the colorimetric determination of chlorine in water was examined.
Analytical Sciences 11/2003; 19(10):1445-7. · 1.25 Impact Factor
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ABSTRACT: For many diseases, mediation of pathogenesis by nitric oxide (NO) has been suggested. In this study, we explored NO-induced viral pathogenesis with a focus on nucleic acid damage as evidenced by 8-nitroguanosine formation in vivo. Wild-type mice and littermate mice deficient in inducible NO synthase (iNOS) were infected with influenza or Sendai virus. Formation of 8-nitroguanosine in virus-infected lungs was assessed immunohistochemically with an antibody specific for 8-nitroguanosine. Extensive nitration of RNA either treated with peroxynitrite or obtained from cultured RAW 264 cells expressing iNOS was readily detected by this antibody. Strong 8-nitroguanosine immunostaining was evident primarily in the cytosol of bronchial and bronchiolar epithelial cells of virus-infected wild-type mice but not iNOS-deficient mice. This staining colocalized with iNOS immunostaining in the lung. 8- Nitroguanosine staining disappeared after addition of exogenous authentic 8-nitroguanosine during the antibody reaction and after pretreatment of tissues with sodium hydrosulfite, which reduces 8-nitroguanosine to 8-aminoguanosine. NO was generated in excess in lungs of wild-type mice but was eliminated in iNOS-deficient mice after virus infection; this result also correlated well with formation of 8-nitroguanosine and 3-nitrotyrosine. One consequence of the lack of iNOS expression was marked improvement in histopathological changes in the lung and the lethality of the infection without effects on cytokine responses and viral clearance. It is intriguing that 8-nitroguanosine markedly stimulated superoxide generation from cytochrome P450 reductase and iNOS in vitro. The present data constitute a demonstration of 8-nitroguanosine formation in vivo and suggest a potential role for NO-induced nitrative stress in viral pathogenesis.
Proceedings of the National Academy of Sciences 02/2003; 100(2):685-90. · 9.68 Impact Factor
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Biochemistry - BIOCHEMISTRY-USA. 01/1993; 32(3):827-832.
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ABSTRACT: The new acid hydrazides, 2-(5-hydrazinocarbonyl-2-thienyl)-5,6-methylenedioxybenzofuran (TMBH) and 2-(5-hydrazin-ocarbonyl-2-furyl)-5, 6-methylenedioxybenzofuran (FMBH), were synthesized as precolumn fluorescence derivatisation reagents for carboxylic acids in liquid chromatography. These compounds readily react with carboxylic acids in the presence of a coupling reagent under mild conditions in aqueous solution to give fluorescent derivatives. The detection limits of lauric acid were both 0.1 pmol per 10 μl injection volume at a signal-to-noise ratio of 3. The methods in which these compounds are used were applied to the assay of a standard mixture of prostaglandins (25 μM) and prostaglandins in a human seminal fluid.
Analytica Chimica Acta. 300:243-251.
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ABSTRACT: A highly water soluble disulfonated tetrazolium salt, 4-[3-(2-methoxy-4-nitrophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate sodium salt, was synthesized. The compound is reduced by NADH in good yields at neutral pHs in the presence of 1-methoxy PMS to produce the corresponding formazan dye that absorbs at 460 nm. The formazan is soluble to water at concentrations higher than 0.1 M. The tetrazolium salt thus proved to be useful as a sensitive chromogenic indicator for NADH. It is also applicable to cell proliferation assays as a cell viability indicator.
Talanta.
