Kyushu University of Health and Welfare
Nobeoka, Japan

Kyushu University of Health and Welfare is a private university in Nobeoka, Miyazaki, Japan, established in 1999. Wikipedia.

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Yamazaki Y.,Shimadzu Corporation | Fujii N.,Kyoto University | Sadakane Y.,Kyushu University of Health and Welfare
Analytical Chemistry | Year: 2010

α-Crystallin, which forms a huge multimeric complex that is essential for maintaining eye lens transparency, is one of the major proteins in the lens. The protein, which exists as isoforms αA and αB, functions as a molecular chaperone to restore the original conformations of distorted constituent proteins in the lens. This function is important to maintain the transparency of the lens, because there is no protein turnover in the lens. Abnormal aggregation of constituent proteins in the lens has been reported in cataract patients, and deamidation of Asn as well as racemization and isomerization of Asp have been found in the α-Crystallin of these patients. While the establishment of a quick and facile analytical method is eagerly anticipated to investigate the relevance of the isomerization to pathological states such as cataracts, differentiating the isomerization states is still not performed routinely. Here, we report the differentiation and semiquantitative analysis of an isoaspartic acid (βAsp) in human α-Crystallin using postsource decay on a MALDI-TOF mass spectrometer incorporating a curved field reflectron. Our reproducible results of analyzing synthetic and tryptic peptides containing βAsp corroborated results obtained using a previously reported diagnostic ion, y l-n+1-46, for the differentiation of βAsp. The relative content of βAsp in the peptide was successfully estimated from a unique ratio, y l-n:y l-n+1, corresponding to cleavages at the C- and N-termini, respectively, of the isomeric residues. The βAsp content was consistent with measurements obtained independently by reversed phase HPLC analysis. Experiments in which neighboring amino acids adjacent to βAsp/Asp were substituted revealed that the ratio between y l-n and y l-n+1 reflected the isomerization status, while the diagnostic ion was observed only in the peptides that included an arginine residue at their C-terminus. Postsource decay experiments utilizing both the diagnostic ion and the characteristic fragment pattern could be applied to various kinds of peptides containing βAsp. © 2010 American Chemical Society.

Nagai T.,National Hospital Organization | Nagai M.,Kyushu University of Health and Welfare
European Archives of Oto-Rhino-Laryngology | Year: 2012

Labyrinthine window rupture (LWR) is one cause of acute sensorineural hearing loss and need for early exploration is clear for good improved hearing. Acute sensorineural hearing loss of 60 dB or more treated from May 2006 to May 2010 were retrospectively analyzed. There were 21 ears of severe deafness, 18 ears of profound deafness, and 10 ears of total deafness. All patients were examined with temporal bone CT. Space-occupying lesions around the labyrinthine windows were suggestive images of LWR. Thirty-five ears were operated for LWR while 14 ears of SHL received conservative treatments. Fifty-seven percent of LWR improved 30 dB or more after sealing of both labyrinthine windows. Of the 15 markedly recovered ears, 14 ears were operated within 2 weeks from the onset. Of the five cured ears, four ears were operated within a week from the onset. As for the hearing prognosis of SHL, 88% of severe and profound deafness improved 30 dB or more but total deafness did not improve more than 30 dB. Exclusion of LWR from SHL and early surgical intervention in LWR will bring about good hearing prognosis to both LWR and SHL. © 2011 The Author(s).

Kawahara M.,Kyushu University of Health and Welfare | Ohtsuka I.,Kyushu University of Health and Welfare | Yokoyama S.,Kyushu University of Health and Welfare | Kato-Negishi M.,University of Tokyo | Sadakane Y.,Kyushu University of Health and Welfare
International Journal of Alzheimer's Disease | Year: 2011

Oligomerization, conformational changes, and the consequent neurodegeneration of Alzheimer's β-amyloid protein (AP) play crucial roles in the pathogenesis of Alzheimer's disease (AD). Mounting evidence suggests that oligomeric APs cause the disruption of calcium homeostasis, eventually leading to neuronal death. We have demonstrated that oligomeric APs directly incorporate into neuronal membranes, form cation-sensitive ion channels ("amyloid channels"), and cause the disruption of calcium homeostasis via the amyloid channels. Other disease-related amyloidogenic proteins, such as prion protein in prion diseases or -synuclein in dementia with Lewy bodies, exhibit similarities in the incorporation into membranes and the formation of calcium-permeable channels. Here, based on our experimental results and those of numerous other studies, we review the current understanding of the direct binding of AP into membrane surfaces and the formation of calcium-permeable channels. The implication of composition of membrane lipids and the possible development of new drugs by influencing membrane properties and attenuating amyloid channels for the treatment and prevention of AD is also discussed. Copyright © 2011 Masahiro Kawahara et al.

Kawahara M.,Kyushu University of Health and Welfare | Kato-Negishi M.,University of Tokyo
International Journal of Alzheimer's Disease | Year: 2011

Whilst being environmentally abundant, aluminum is not essential for life. On the contrary, aluminum is a widely recognized neurotoxin that inhibits more than 200 biologically important functions and causes various adverse effects in plants, animals, and humans. The relationship between aluminum exposure and neurodegenerative diseases, including dialysis encephalopathy, amyotrophic lateral sclerosis and Parkinsonism dementia in the Kii Peninsula and Guam, and Alzheimer's disease (AD) has been suggested. In particular, the link between aluminum and Alzheimer's disease has been the subject of scientific debate for several decades. However, the complex characteristics of aluminum bioavailability make it difficult to evaluate its toxicity and therefore, the relationship remains to be established. Mounting evidence has suggested that significance of oligomerization of β-amyloid protein and neurotoxicity in the molecular mechanism of AD pathogenesis. Aluminum may play crucial roles as a cross-linker in β-amyloid oligomerization. Here, we review the detailed characteristics of aluminum neurotoxicity based on our own studies and the recent literatures. Our aim is to revisit the link between aluminum and AD and to integrate aluminum and amyloid cascade hypotheses in the context of β-amyloid oligomerization and the interactions with other metals. © 2011 Masahiro Kawahara and Midori Kato-Negishi.

Takahashi S.,Mukogawa Women's University | Takahashi S.,Kyushu University of Health and Welfare | Nakashima Y.,Kyushu University of Health and Welfare
British Journal of Nutrition | Year: 2012

In the present study, we examined the effect of repeated and long-term treatment with resveratrol on NO production in endothelial cells as a model of routine wine consumption. Repeated treatment with resveratrol for 5 d resulted in an increase in endothelial NO synthase (eNOS) protein content and NO production in human umbilical vein endothelial cell (HUVEC) in a concentration-dependent manner. A significant increase in functional eNOS protein content was observed with resveratrol, even at 50 nm. In contrast, eNOS phosphorylation was not stimulated and inducible NO synthase (iNOS) was not detected after resveratrol treatment. Both eNOS protein and mRNA expression were promoted by 50 nm-resveratrol in a time-dependent manner. Increased eNOS mRNA expression in response to resveratrol was not decreased by an oestrogen receptor (ER) antagonist ICI182780, a PPARα inhibitor MK886 or a sirtuin inhibitor Salermide. However, a combination of ICI182780 and MK886 significantly inhibited resveratrol-induced eNOS mRNA expression. Salermide had no effect even in the presence of ICI182780 or MK886. These results demonstrate that resveratrol within the physiological range increases eNOS mRNA and protein expression through ER and PPARα activation, thereby promoting NO production in endothelial cells. eNOS induction might result from the accumulative effect of nanomolar concentrations of resveratrol. The present study results can account in part for the observation that cardiovascular benefits of red wine are experienced with routine consumption, but not with acute consumption. © 2011 The Authors.

Yamaori S.,Hokuriku University | Maeda C.,Hokuriku University | Yamamoto I.,Kyushu University of Health and Welfare | Watanabe K.,Hokuriku University
Forensic Toxicology | Year: 2011

Inhibitory effects of Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD), and cannabinol (CBN) on the catalytic activities of human recombinant cytochrome P450 (CYP) 2A6 and CYP2B6 were investigated. Δ9-THC, CBD, and CBN noncompetitively inhibited coumarin 7-hydroxylase activity of recombinant CYP2A6 with the apparent K i values of 28.9, 55.0, and 39.8 μM, respectively. On the other hand, Δ9-THC, CBD, and CBN inhibited 7-benzoxyresorufin O-debenzylase activity of recombinant CYP2B6 in a mixed fashion with the K i values of 2.81, 0.694, and 2.55 μM, respectively. Because the inhibition of CYP2B6 by CBD was the most potent, investigation was conducted to determine which moiety of the CBD structure was responsible for the inhibition. Olivetol and d-limonene, the partial structure of CBD, inhibited the CYP2B6 activity to some extent. Inhibitory effects of CBD-2′-monomethyl ether and CBD-2′,6′-dimethyl ether attenuated with the number of methylations on the phenolic hydroxyl groups in the resorcinol moiety of CBD. Cannabidivarin, a CBD analogue having a propyl side chain, inhibited the CYP2B6 activity less potently than CBD possessing a pentyl side chain. Therefore, both structures of pentylresorcinol and terpene moieties of CBD were suggested to play important roles in the CYP2B6 inhibition. Δ9-THC, CBD, and CBN showed metabolism-dependent inhibition for CYP2A6 but not for CYP2B6. Furthermore, Δ9-THC and CBN were characterized as mechanism-based inhibitors for CYP2A6. The k inact and K I values of Δ9-THC were 0.0169 min -1 and 0.862 μM, respectively; the k inact and K I values of CBN were 0.00909 min-1 and 1.01 μM, respectively. These results indicated that Δ9-THC, CBD, and CBN showed differential inhibition against CYP2A6 and CYP2B6. © 2011 Japanese Association of Forensic Toxicology and Springer.

Yamaori S.,Hokuriku University | Kushihara M.,Hokuriku University | Yamamoto I.,Kyushu University of Health and Welfare | Watanabe K.,Hokuriku University
Biochemical Pharmacology | Year: 2010

Inhibitory effects of Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD), and cannabinol (CBN), the three major constituents in marijuana, on catalytic activities of human cytochrome P450 (CYP) 1 enzymes were investigated. These cannabinoids inhibited 7-ethoxyresorufin O-deethylase activity of recombinant CYP1A1, CYP1A2, and CYP1B1 in a competitive manner. CBD most potently inhibited the CYP1A1 activity; the apparent Ki value (0.155μM) was at least one-seventeenth of the values for other CYP1 isoforms. On the other hand, CBN more effectively decreased the activity of CYP1A2 and CYP1B1 (Ki=0.0790 and 0.148μM, respectively) compared with CYP1A1 (Ki=0.541μM). Δ9-THC less potently inhibited the CYP1 activity than CBD and CBN, and showed low selectivity against the CYP1 inhibition (Ki=2.47-7.54μM). The preincubation of CBD resulted in a time- and concentration-dependent decrease in catalytic activity of all the recombinant CYP1 enzymes and human liver microsomes. Similarly, the preincubation of Δ9-THC or CBN caused a time- and concentration-dependent inhibition of recombinant CYP1A1. The inactivation of CYP1A1 by CBD indicated the highest kinact/KI value (540l/mmol/min) among the CYP1 enzyme sources tested. The inactivation of recombinant CYP1A1 and human liver microsomes by CBD required NADPH, was not influenced by dialysis and by glutathione, N-acetylcysteine, and superoxide dismutase as trapping agents. These results indicated that CBD and CBN showed CYP1 isoform-selective direct inhibition and that CBD was characterized as a potent mechanism-based inhibitor of human CYP1 enzymes, especially CYP1A1. © 2010 Elsevier Inc.

Kawahara M.,Kyushu University of Health and Welfare | Koyama H.,Kyushu University of Health and Welfare | Nagata T.,Kyushu University of Health and Welfare | Sadakane Y.,Kyushu University of Health and Welfare
Metallomics | Year: 2011

Prion diseases are progressive neurodegenerative diseases that are associated with the conversion of normal cellular prion protein (PrP C) to abnormal pathogenic prion protein (PrP SC) by conformational changes. Prion protein is a metal-binding protein that is suggested to be involved in metal homeostasis. We investigated here the effects of trace elements on the conformational changes and neurotoxicity of synthetic prion peptide (PrP106-126). PrP106-126 exhibited the formation of β-sheet structures and enhanced neurotoxicity during the aging process. The co-existence of Zn 2+ or Cu 2+ during aging inhibited β-sheet formation by PrP106-126 and attenuated its neurotoxicity on primary cultured rat hippocampal neurons. Although PrP106-126 formed amyloid-like fibrils as observed by atomic force microscopy, the height of the fibers was decreased in the presence of Zn 2+ or Cu 2+. Carnosine (β-alanyl histidine) significantly inhibited both the β-sheet formation and the neurotoxicity of PrP106-126. Our results suggested that Zn 2+ and Cu 2+ might be involved in the pathogenesis of prion diseases. It is also possible that carnosine might become a candidate for therapeutic treatments for prion diseases. © 2011 The Royal Society of Chemistry.

Jiang R.,Hokuriku University | Yamaori S.,Hokuriku University | Okamoto Y.,Hokuriku University | Yamamoto I.,Kyushu University of Health and Welfare | Watanabe K.,Hokuriku University
Drug Metabolism and Pharmacokinetics | Year: 2013

The present study investigated the inhibitory effect of cannabidiol (CBD), a major constituent of marijuana, on the catalytic activity of cytochrome P450 2C19 (CYP2C19). (S)-Mephenytoin 4′-hydroxylase activities of human liver microsomes (HLMs) and recombinant CYP2C19 were inhibited by CBD in a concentration-dependent manner (IC50 = 8.70 and 2.51 μM, respectively). Omeprazole 5-hydroxylase and 3-O-methylfluorescein O-demethylase activities in recombinant CYP2C19 were also strongly inhibited by CBD (IC50 = 1.55 and 1.79 μM, respectively). Kinetic analysis for inhibition revealed that CBD showed a mixed-type inhibition against (S)-mephenytoin 4′-hydroxylation by recombinant CYP2C19. To clarify the structural requirements for CBD-mediated CYP2C19 inhibition, the effects of CBD-related compounds on CYP2C19 activity were examined. Olivetol inhibited the (S)-mephenytoin 4′-hydroxylase activity of recombinant CYP2C19 with the IC50 value of 15.3 μM, whereas d-limonene slightly inhibited the activity (IC50 > 50 μM). The inhibitory effect of CBD-2′-monomethyl ether (IC50 = 1.88 μM) on CYP2C19 was comparable to that of CBD, although the inhibitory potency of CBD-2′,6′-dimethyl ether (IC50 = 14.8 μM) was lower than that of CBD. Cannabidivarin, possessing a propyl side chain, showed slightly less potent inhibition (IC50 = 3.45 μM) as compared with CBD, whereas orcinol and resorcinol did not inhibit CYP2C19 activity at all. These results indicate that CBD caused potent CYP2C19 inhibition, in which one free phenolic hydroxyl group and the pentyl side chain of CBD may play important roles. © 2013 by the Japanese Society for the Study of Xenobiotics (JSSX).

Yoshida H.,Kyushu University of Health and Welfare | Watanabe W.,Kyushu University of Health and Welfare | Oomagari H.,Kyushu University of Health and Welfare | Tsuruta E.,Kyushu University of Health and Welfare | And 2 more authors.
Journal of Nutritional Biochemistry | Year: 2013

Toll-like receptors (TLRs) were recently shown to be involved in obesity-induced inflammation in adipose tissue, which contributes to the development of insulin resistance and type 2 diabetes. Thus, the appropriate regulation of TLR expression or activation is an important strategy for improving obesity-related diseases. In this report, we show that naringenin, a citrus flavonoid, inhibits TLR2 expression during adipocyte differentiation. This effect is mediated in part through peroxisome proliferator-activated receptor γ activation. In addition, naringenin suppresses TLR2 expression induced by the co-culture of differentiated adipocytes and macrophages and also inhibits tumor necrosis factor-α (TNF-α)-induced TLR2 expression by inhibiting the activation of nuclear factor-κB and c-Jun NH2-terminal kinase pathways in differentiated adipocytes. Furthermore, naringenin decreases TLR2 expression in adipose tissue of high-fat diet-fed mice. These results are correlated with the improvement of hyperglycemia and the suppression of inflammatory mediators, including TNF-α and monocyte chemotactic protein-1. Taken together, these data suggest that naringenin exhibits anti-inflammatory properties, presumably by inhibiting TLR2 expression in adipocytes. Our findings suggest a molecular mechanism by which naringenin exerts beneficial effects against obesity-related diseases. © 2013 Elsevier Inc.

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