Naoshi Yamazaki, Keisuke Kanazawa, Maria Kimura, Hironobu Ike, Makiko Shinomiya, Shouko Tanaka, Yasuo Shinohara, Noriaki Minakawa, Kouji Itou and Yoshiharu Takiguchi : Use of modified U1 small nuclear RNA for rescue from exon 7 skipping caused by 5-splice site mutation of human cathepsin A gene, Gene, Vol.677, 41-48, 2018.
(要約)
Cathepsin A (CTSA) is a multifunctional lysosomal enzyme, and its hereditary defect causes an autosomal recessive disorder called galactosialidosis. In a certain number of galactosialidosis patients, a base substitution from adenine to guanine is observed at the +3 position of the 7th intron (IVS7 +3a>g) of the CTSA gene. With this mutation, a splicing error occurs; and consequently mRNA lacking the 7th exon is produced. This skipping of exon 7 causes a frame shift of the transcripts, resulting in a non-functional CTSA protein and hence galactosialidosis. This mutation seems to make the interaction between the 5'-splice site of intron 7 of pre-mRNA and U1 small nuclear RNA (U1 snRNA) much weaker. In the present study, to produce properly spliced mRNA from the CTSA gene harboring this IVS7 +3a>g mutation, we examined the possible usefulness of modified U1 snRNA that could interact with the mutated 5'-splice site. Toward this goal, we first prepared a model system using a mutant CTSA mini gene plasmid for delivery into HeLa cells. Then, we examined the effectiveness of modified U1 snRNA on the formation of properly spliced mRNA from this mutant CTSA mini gene. As a result, we succeeded in obtaining improved formation of properly spliced CTSA mRNA. Our results suggest the usefulness of modified U1 snRNA for rescue from exon 7 skipping caused by the IVS7 +3a>g mutation of the CTSA gene.
Shimokawa Yoshihiko, Yoda Noriaki, Kondo Satoshi, Yamamura Yoshiya, Yoshiharu Takiguchi and Umehara Ken : Inhibitory Potential of Twenty Five Anti-tuberculosis Drugs on CYP Activities in Human Liver Microsomes, Biological & Pharmaceutical Bulletin, Vol.38, No.9, 1425-1429, 2015.
(要約)
The direct inhibitory potential of twenty five anti-tuberculosis drugs on eight CYP-specific reactions in human liver microsomes was investigated to predict in vivo drug-drug interactions (DDIs) from in vitro data. Rifampicin, rifabutin, and thioacetazone inhibited one CYP reaction. Isoniazid and clofazimine had inhibitory effects on four CYP reactions, and rifapentine, ethionamide, and prothionamide widely inhibited CYP reactions. Based on the inhibition constant (Ki) and the therapeutic total inhibitor concentrations [I]max of eight drugs in human plasma, [I]max/Ki values were calculated to evaluate clinical DDIs. The [I]max/Ki values were 0.20 or less for rifampicin, rifabutin, and thioacetazone; 0.15-2.0 for isoniazid; 0.14-1.5 for rifapentine; 0.29-1.4 for ethionamide; 0.41-2.2 for prothionamide; and 0.12-6.3 for clofazimine. The highest [I]max/Ki values were 2.0 for isoniazid on CYP3A4 [testosterone (T)]; 1.5 for rifapentine on CYP3A4 [midazolam (M)]; 1.4 for ethionamide on CYP2C8; 2.2, 1.8, and 1.3 for prothionamide on CYP2B6, CYP2C19, and CYP2C8, respectively; and 6.3 and 5.7 for clofazimine on CYP3A4 (M) and CYP3A4 (T), respectively. These drugs with high [I]max/Ki values lead to clinical DDIs. Considering the drug regimens for tuberculosis (TB) and co-infection with TB and human immunodeficiency virus, the inhibitory potential for CYP3A4 and CYP2B6 is particularly important. These results suggest that clofazimine and prothionamide are likely to cause clinically relevant DDIs when co-administered with products metabolized by CYP3A4 and CYP2B6, respectively. Isoniazid and rifapentine may cause DDIs with drugs metabolized by CYP3A4.
Takenori Yamamoto, Mika Ito, Keita Kageyama, Kana Kuwahara, Kikuji Yamashita, Yoshiharu Takiguchi, Seiichiro Kitamura, Hiroshi Terada and Yasuo Shinohara : Mastoparan peptide causes mitochondrial permeability transition not by interacting with specific membrane proteins but by interacting with the phospholipid phase., The FEBS Journal, Vol.281, No.17, 3933-3944, 2014.
(要約)
The mastoparan peptide is known as an inducer of the mitochondrial permeability transition. Although mastoparan was suggested to interact with a proteinaceous target in mitochondria to induce this transition, the action sites of mastoparan have not yet been investigated. To clarify whether specific interactions of mastoparan with receptors or enzymes are associated with the induction of this permeability transition, we examined the effects of d-isomeric peptides, which were synthesized using d-amino acids assembled in endogenous (inverso mastoparan) and reverse (retro-inverso mastoparan) orientations. When we added inverso mastoparan to isolated mitochondria, the peptide caused the permeability transition in a partially cyclosporin A-sensitive manner at lower doses and in a cyclosporin A-insensitive manner at higher ones. The manners of action and the potencies of inverso mastoparan were close to those of parent mastoparan, indicating that the targets of mastoparan for induction of the permeability transition were neither receptors, nor enzymes in the mitochondria. Retro-inverso mastoparan also had the same effect on the mitochondria as mastoparan, although the potencies of the effect were weaker. Not only on mitochondria, but also on phospholipid vesicles, mastoparan and inverso mastoparan showed massive permeabilization effects at the same potencies, although retro-inverso mastoparan showed weaker ones. These results indicate that mastoparan interacted with the phospholipid phase of the mitochondrial membrane (and not with specific proteins) to induce the permeabilization in cyclosporin A-sensitive and -insensitive manners.
(キーワード)
Animals / Cyclosporine / Male / Membrane Lipids / Mitochondria, Liver / Mitochondrial Membrane Transport Proteins / Mitochondrial Membranes / Peptides / Phosphatidylcholines / Rats / Stereoisomerism / Wasp Venoms
Takuya Hada, Takenori Yamamoto, Atsushi Yamamoto, Kazuto Ohkura, Naoshi Yamazaki, Yoshiharu Takiguchi and Yasuo Shinohara : Comparison of the catalytic activities of three isozymes of carnitine palmitoyltransferase 1 expressed in COS7 cells, Applied Biochemistry and Biotechnology, Vol.172, No.3, 1486-1496, 2014.
(要約)
The enzyme carnitine palmitoyltransferase 1 (CPT1) catalyzes the transfer of an acyl group from acyl-CoA to carnitine to form acylcarnitine, and three isozymes of it, 1a, 1b, and 1c, have been identified. Interestingly, the 1c isozyme was reported to show no enzymatic activity, but it was not clearly demonstrated whether this inactivity was due to its dysfunction or due to its poor expression. In the present study, we (a) expressed individual CPT1 isozymes in COS7 cells, (b) evaluated quantitatively their expression levels by Western blotting using the three bacterially expressed CPT1 isozymes as standards, and (c) evaluated their catalytic activities. With these experiments, we successfully demonstrated that the absence of the enzymatic activity of the 1c isozyme was due to its dysfunction. In addition, experiments on the preparation of standard CPT1 isozymes revealed that the 1c isozyme did not show the standard relationship between migration in an SDS-PAGE gel and molecular size. We further tried to determine why the 1c isozyme was inert by preparing chimeric CPT1 between 1a and 1c, but no clear conclusion could be drawn because one of the chimeric CPT1s was not sufficiently expressed.
(キーワード)
Acyl Coenzyme A / Animals / COS Cells / Carnitine O-Palmitoyltransferase / Cercopithecus aethiops / Electrophoresis, Polyacrylamide Gel / Gene Expression Regulation / Isoenzymes / Kinetics / Mitochondria, Liver
Yusaku Kikuchi, Naoshi Yamazaki, Noriko Tarashima, Kazuhiro Furukawa, Yoshiharu Takiguchi, Kouji Itou and Noriaki Minakawa : Gene suppression via U1 small nuclear RNA interference (U1i) machinery using oligonucleotides containing 2'-modified-4'-thionucleosides, Bioorganic & Medicinal Chemistry, Vol.21, No.17, 5292-5296, 2013.
(要約)
Gene suppression via U1 small nuclear RNA interference (U1i) is considered to be one of the most attractive approaches, and takes the place of general antisense, RNA interference (RNAi), and anti-micro RNA machineries. Since the U1i can be induced by short oligonucleotides (ONs), namely U1 adaptors consisting of a 'target domain' and a 'U1 domain', we prepared adaptor ONs using 2'-modified-4'-thionucleosides developed by our group, and evaluated their U1i activity. As a result, the desired gene suppression via U1i was observed in ONs prepared as a combination of 2'-fluoro-4'-thionucleoside and 2'-fluoronucleoside units as well as only 2'-fluoronucleoside units, while those prepared as combination of 2'-OMe nucleoside/2'-OMe-4'-thionucleoside and 2'-fluoronucleoside units did not show significant activity. Measurement of Tm values indicated that a higher hybridization ability of adaptor ONs with complementary RNA is one of the important factors to show potent U1i activity.
Formative assessment which refers to frequent, interactive assessments of student progress and understanding is one of the most effective strategies for promoting high student performance and developing students' "learning to learn" skills. Portfolio (personal record of learning) is a useful tool for tracking individual student progress toward learning goals. We conducted the questionnaire survey in 14 National Universities on approach to the formative assessment methods and the use of portfolio in the long-term practice experience (pharmacy clerkship) at community pharmacy and hospital pharmacy which was undergone for the first time in 2010. The finding obtained from our questionnaires implicated that portfolio is useful for sharing information among student, tutorial pharmacist and faculty members. All universities have provided tools for visible assessment of student achievement. However, they are not used enough for feedback on student performance, and formative assessment is not practiced systematically. A reason seems to be differences in understanding of it. In addition to improvement of the tools to support formative assessment, promotion of effective assessment practice will need for systematic evaluation.
S. Nishibayashi, K. Hattori, T. Hirano, K. Uehara, Y. Nakano, M. Aihara, Y. Yamada, M. Muraguchi, F. Iwata and Yoshiharu Takiguchi : Functional and structural changes in end-stage kidney disease due to glomerulonephritis induced by the recombinant alpha3(IV)NC1 domain., Experimental Animals, Vol.59, No.2, 157-170, 2010.
(要約)
The aim of this study was to develop and characterize a rat glomerulonephritis model, which progresses to renal fibrosis and renal failure. A single immunization of female WKY rats with more than 10 microg of recombinant alpha3(IV)NC1 protein caused severe proteinuria followed by progressive increases in plasma creatinine and blood urea nitrogen (BUN) level within 42 days. Sequential histopathological evaluation revealed crescent formation in glomeruli followed by tubular dilation and interstitial fibrosis. Hydroxyproline content and expression of type I collagen and smooth muscle actin genes in the renal cortex increased as renal dysfunction progressed. Furthermore, the TGF-beta1 level in the renal cortex also increased. In the evaluation of antinephritic agents in this model, prednisolone and mycophenolate mofetil (MMF) treatment significantly decreased plasma creatinine and BUN, and suppressed renal fibrosis and histological changes involving crescent formation, compared with the vehicle-treated nephritic rats, whereas lisinopril treatment failed to improve renal function and histology. We demonstrated that immunization of female WKY rats with a sufficient dose of recombinant alpha3(IV)NC1 induces end-stage kidney disease accompanied by renal fibrosis. The relatively short period needed to induce the disease and the high incidence of functional and structural changes were considered a great advantage of this model for clarifying the mechanisms of progressive glomerulonephritis and for evaluating agents used to treat renal failure.
H. Kawazoe, H. Dobashi, T. Kameda, K. Susaki, K. Kittaka, M. Tokuda, N. Fukuoka, Yoshiharu Takiguchi and H. Houchi : Prospective study to assess the optimal blood concentration of tacrolimus in Japanese patients with rheumatoid arthritis, Journal of Health Science, Vol.55, No.3, 435-440, 2009.
Hitoshi Kawazoe, kyoko Takaoka, Hirofumi Shibata, Naokatu Arakaki, Tomihiko Higuti, K Negayama, Hitoshi Houchi, Koichiro Tsuchiya and Yoshiharu Takiguchi : Comparison of antibacterial activity of fluoroquinolones with their sucralfate-complexes against clinically-isolated bacteria, Journal of Health Science, Vol.55, No.5, 790-795, 2009.
(要約)
Oral fluoroquinolones are widely known to form chelate complexes with metal-containing drugs, resulting in inhibition of their intestinal absorption. However, for intestinal sterilization, the concomitant regimen may be a selective and effective strategy due to decreased absorption of fluoroquinolones result in the retainment of antibiotics at the intestine if the mixture still perpetuated antibacterial activity. Therefore, to clarify whether the mixture of fluoroquinolones and sucralfate affects their antibacterial activity or not, we conducted in vitro study. According from the checkerboard study using a microdilution method with Mueller-Hinton broth, the antibacterial activity of these fluoroquinolones-sucralfate mixtures equaled to the parent fluoroquinolones even in the presence of sucralfate at the molar ratio of [sucralfate: fluoroquinolone] was less than 166, and the minimal inhibitory concentrations for clinical isolated Escherichia coli and Pseudomonas aeruginosa strains were independent of the existence of sucralfate. These data imply that the chelated forms of each fluoroquinolone retain antibacterial activity even in the presence of the recommended therapeutic doses of sucralfate in clinical practice.
Masahiro Abe, Yoshiharu Takiguchi, Satoshi Ichimaru, Shinichiro Kaji, Koichiro Tsuchiya and Koichiro Wada : Different effect of acute treatment with rosiglitazone on rat myocardial ischemia/reperfusion injury by administration method., European Journal of Pharmacology, Vol.589, No.1-3, 215-219, 2008.
(要約)
The present study was undertaken to examine the effect of rosiglitazone, a peroxisome proliferator-activated receptor (PPAR)-gamma agonist, using different administration methods, on rat myocardial infarct size induced by 30 min of ischemia followed by 4 h of reperfusion. The infarct size was significantly reduced by the continuous infusion of rosiglitazone (0.5 mg/kg/h) from 30 min before occlusion for 2 h. On the other hand, limitation of the infarct size was shown by a bolus injection of 0.75 mg/kg at 5 min before reperfusion, but not by a bolus injection of 1 mg at 30 min before occlusion. The protective effect of rosiglitazone by the bolus injection before occlusion was obtained when an antioxidant, N-acetylcysteine, was concomitantly administered. The cardioprotection by rosiglitazone was associated with the inhibition of increased myeloperoxidase activity, tumor necrosis factor-alpha content and phosphorylation of inhibitor kappaB in the myocardium. The present study demonstrated that the protective effect of rosiglitazone on myocardial ischemia/reperfusion injury occurred most likely by inhibition of the nuclear factor-kappaB pathway through PPAR-gamma activation. However, acute treatment with rosiglitazone is harmful if its concentration is high during ischemia.
Masahiro Abe, Yoshiharu Takiguchi, Satoshi Ichimaru, Koichiro Tsuchiya and Koichiro Wada : Comparison of the protective effect of N-acetylcysteine by different treatments on rat myocardial ischemia-reperfusion injury., Journal of Pharmacological Sciences, Vol.106, No.4, 571-577, 2008.
(要約)
Reactive oxygen species have been known as important contributors to ischemia/reperfusion (I/R) injury. Studies on the beneficial effect of N-acetylcysteine (NAC), a potent antioxidant, on limiting infarct size induced by I/R yielded contrasting results. The present study was undertaken to compare the effect of NAC by different administration methods on infarct size in a rat myocardial I/R model. Rats underwent 30 min of left coronary occlusion followed by 4 h of reperfusion. Treatment with continuous infusion of NAC (150 mg/kg per hour) from 30 min before occlusion for 2 h (until 1 h after the start of reperfusion) produced a significant limitation of the infarct size as a percentage of the ischemic area (8%) compared to the non-treated control (60%). However, bolus injection of 150 mg/kg at 30 min prior to occlusion and 5 min prior to reperfusion failed to reduce it (56%) although the total dose is the same. The decreased total glutathione content and glutathione peroxidase activity in the ischemic region were recovered in the continuous infusion group, but not in the bolus injection group. The increased myeloperoxidase activity and phosphorylation of inhibitor kappaB after I/R were inhibited by the continuous treatment. These results indicate that the protective effect of NAC on myocardial infarction induced by I/R was different depending on the administration method. It is necessary to maintain blood concentration during the early period of reperfusion to obtain the beneficial effect of NAC.
Infections caused by multiple-drug-resistant Pseudomonas aeruginosa (MDRP) are a clinically significant problem. We reported here the effective use of combination therapy in a patient with infection caused by MDRP according to an interventional treatment strategy suggested by a pharmacist. The patient was a 70-year-old male who underwent allogeneic hematopoietic stem cell transplantation. On day 45 after transplant, MDRP was newly isolated from urine, but the diagnosis at that time was colonization. On day 61, the patient developed a fever (≧ 38.0℃). In addition, laboratory data showed that C-reactive protein (CRP) was also increased. At the medical team conference, the pharmacist proposed the following treatment strategy for this infection. Aztreonam and amikacin were intravenously administered at doses of 2 g/day and 800 mg/day, respectively. The subsequent clinical course was well controlled, but the infection recurred and was aggravated. Aztreonam and ciprofloxacin were then intravenously administered at doses of 4 g/day and 600 mg/day, respectively, resulting in the alleviation of fever in the patient as well as a decrease in CRP and disappearance of MDRP isolates from urine on day 67; that is, MDRP infection was consequently well controlled. In conclusion, the combination therapy between aztreonam and amikacin, or ciprofloxacin may be clinically useful for severe infections of MDRP in compromised hosts.
We performed a retrospective study to examine the preventive effects of newquinolones for endogenous infection in patients receiving various allogeneic hematopoietic stem cell transplantation including bone marrow transplantation (BMT), peripheral blood stem cell transplantation (PBSCT), and cord blood transplantation (CBT). Forty-nine patients were enrolled. Ciprofloxacin or norfloxacin was orally administered for intestinal sterilization from day -14 until engraftment. As a result, the period from transplantation until engraftment was significantly longer in CBT group than in BMT group. The febrile index (the ratio of the febrile (> or =38.0 degrees C) period during neutropenia (< or =500 cells/mm(3)) and C-reactive protein (CRP)-positive index (the ratio of CRP-positive (> or =2.0 mg/dl) period during neutropenia) were comparable among the three groups. In addition, no gram-negative bacteria in stool was isolated in the three groups; that is, an endogenous infection of gram-negative bacteria, a potential pathogen, was well controlled by newquinolones. We should be careful when interpreting the results of this small study; however, newquinolones are clinically effective for endogenous infection of gram-negative bacteria in patients receiving not only BMT, but also PBSCT and CBT.
Hitoshi Kawazoe, Yoshiharu Takiguchi, Hiroaki Tanaka, Chiaki Doi, Noriyasu Fukuoka, Nobuhiro Kanaji, Shuji Bandoh, Toshihiko Ishida and Hitoshi Houchi : Preventive effects of low-dose dexamethasone for delayed adverse events induced by carboplatin-based combination chemotherapy, Journal of the Pharmaceutical Society of Japan, Vol.127, No.6, 1001-1006, 2007.
(要約)
We performed a retrospective study to examine the protective effect of low-dose dexamethasone (DEX) on delayed adverse events induced by carboplatin (CBDCA)-based combination chemotherapy in patients with thoracic tumors. Low-dose DEX (4-8 mg/day) was administered on day 1 and after, in addition to a serotonin 5-HT3 receptor antagonist. The acute adverse events (day 1) were well controlled in the patients with or without co-treatment of DEX. On the other hand, the delayed nausea, emesis, anorexia, and fatigue after day 2 failed to be controlled by 5-HT3 antagonist alone. Co-treatment with DEX significantly suppressed the grade of the delayed adverse events during days 2-10. The mean ratio of complete protection during days 2-10 were significantly higher in the DEX-treated group compared with the non-DEX-treated group. These results reveal that low-dose DEX is a clinically effective treatment for the prevention of delayed adverse events induced by CBDCA-based combination chemotherapy.
Hitoshi Kawazoe, Yoshiharu Takiguchi, Hiroaki Tanaka, Noriyasu Fukuoka, Hiroaki Ohnishi, Toshihiko Ishida and Hitoshi Houchi : Change of the blood concentration of tacrolimus after the switch from fluconazole to variconazole in patients receiving allogeneic hematopoietic stem cell transplantation, Biological & Pharmaceutical Bulletin, Vol.29, No.12, 2528-2531, 2006.
(要約)
The purpose of this study was to assess the impact by switching co-administered triazole antifungal agent from fluconazole (FCZ) to voriconazole (VCZ) on the blood concentration of tacrolimus (FK506) in patients receiving allogeneic hematopoietic stem cell transplantation. We performed a retrospective study presented as case reports. The blood concentration of FK506 was increased after the switch from FCZ to VCZ, resulting in increase of the concentration/dose (C/D) ratio of FK506. Thus, the mean C/D ratios of FK506 with oral administration was surprisingly increased over 4.5-fold after the switch. Therefore, it was necessary to reduce the FK506 dose when co-administered FCZ is switched to VCZ. We should be careful when interpreting the results of these case reports; however, in some patients, it is recommended that the dose of FK506 be reduced to one-fifth after the switch.
The purpose of this study was to assess patient participation in cancer therapy and the sharing of patient information among the medical care team (physicians, nurses, pharmacists, and especially patients). We monitored the side effects of cancer chemotherapy with patients, and developed two support tools: One scored the points of subjective symptoms (fatigue, anorexia, nausea, etc) by patients, and the other recorded objective symptoms (clinical examination data) by pharmacists. It is most important that they attend each patient at their bedside. At this time, the trial was evaluated by questionnaire survey by inpatients receiving cancer chemotherapy (n=15). As a result, all patients (15/15) responded that this trial was necessary. This trial addressed the following: 1) increased communication between patients and medical staff concerning side effects (14/15), 2) increased interest in side effects (10/15), 3) when a patient tells medical staff about side effects, they act on it (10/15). None of the patients felt inconvenienced by scoring every day (0/15), or anxiety about side effects (0/15). Furthermore, all patients (15/15) responded that "participation of pharmacists in cancer chemotherapy" was necessary. This trial revealed no problems and suggested that patients related to the center of medical care. We should be careful in interpreting results of this small sized trial; however, the following conclusions should be reached: 1) introduction of monitoring side effects of cancer chemotherapy with patients, 2) develop communication among the medical care team.
(キーワード)
cancer chemotherapy / side effects monitoring / patient participation / sharing patient information / medical care team
Otsuka Toshihiro, Keisuke Izumi, Itsuo Tokunaga, Takako Gotohda, Ipposhi Kaneshige, Yoshiharu Takiguchi, Kaneda Shinya, Nobuo Satake, Takamasa Ohnishi, Seiki Tashiro and Mitsuo Shimada : Prevention of lethal hepatic injury in Long-Evans Cinnamon(LEC) rats by D-galactosamine hydrochloride, The Journal of Medical Investigation : JMI, Vol.53, No.1-2, 81-86, 2006.
(要約)
Repeated injections of D-galactosamine hydrochloride (GalN) increase the survival rate of Long-Evans Cinnamon (LEC) rats, an animal model of Wilson's disease. The aim of the present study was to investigate the mechanism of GalN for prevention of spontaneous lethal hepatic injury in LEC rats. Male LEC rats were given a single subcutaneous injection of 300 mg/kg of GalN or vehicle (0.9% NaCl) at 14 weeks, and killed at 28 weeks of age. Next, 6-week-old male LEC rats were given weekly subcutaneous injections of 300 mg/kg of GalN or vehicle for 3 or 12 weeks, and their hepatic 8-hydroxydeoxy-2'-guanosine (8-OHdG), glutathione peroxidase (GPX), and catalase activities were measured. None of GalN-treated rats died of hepatic injury (0/12), whereas the mortality rate of control rats given 0.9% NaCl was 17% (2/12). GalN administration for 12 weeks decreased the hepatic 8-OHdG, and GalN administration for either 3 or 12 weeks increased the glutathione peroxidase activity. GalN administration increased the serum level of alanine aminotransferase, and accelerated megalocytic degeneration of the hepatocytes. GalN treatment is effective in preventing lethal hepatitis in LEC rats and decrease of oxidative DNA damage by GalN plays an important role in increase of the survival rate.
Koichiro Tsuchiya, Kaori Akai, Akira Tokumura, Shinji Abe, Toshiaki Tamaki, Yoshiharu Takiguchi and Kenji Fukuzawa : Oxygen radical photo-induced by ferric nitrilotriacetate complex, Biochimica et Biophysica Acta (BBA) - General Subjects, Vol.1725, No.1, 111-119, 2005.
(要約)
This study examined the photo-induced generation of reactive oxygen species (ROS) by the carcinogenic iron(III)-NTA complex. Iron(III)-NTA complex (1:1) has three conformations (type (a) in acidic conditions of pH 1-6, type (n) in neutral conditions of pH 3-9, and type (b) in basic conditions of pH 7-10) with two pK(a) values (pK(a1) approximately 4, pK(a2) approximately 8). The iron(III)-NTA complex was reduced to iron(II) under cool-white fluorescent light without the presence of any reducing agent, and the reduction rates of the three conformations of iron(III)-NTA were in the order type (a)>type (n)>type (b) as reported previously (Akai K. et al., Free Radic. Res. 38, 951-962, 2004). ROS generation was investigated by electron paramagnetic resonance (EPR) spectroscopy with a spin-trapping technique. Apparent EPR signals attributed to PBN/*(13)CH(3) and PBN/*OCH(3) spin adducts were observed after incubation of the iron(III)-NTA complex was mixed with alpha-phenyl-tert-butylnitrone (PBN) and (13)C-DMSO in an aerobic condition. The addition of catalase effectively attenuated the PBN adducts, but superoxide dismutase enhanced them. Taken together, these results indicate that the iron(III)-NTA complex is spontaneously reduced to the iron(II)-NTA complex by light under acidic to neutral pH, and in turn transfers an electron to molecular oxygen to form ROS.
Koichiro Tsuchiya, Yasuhisa Kanematsu, Masanori Yoshizumi, Hideki Ohnishi, Kazuyoshi Kirima, Yuki Izawa, Michiyo Shikishima, Tatsuhiro Ishida, Shuji Kondo, Shoji Kagami, Yoshiharu Takiguchi and Toshiaki Tamaki : Nitrite is an alternative source of NO in vivo, American Journal of Physiology, Heart and Circulatory Physiology, Vol.288, No.5, H2163-H2170, 2005.
(要約)
In this study, we investigated whether orally administered nitrite is changed to NO and whether nitrite attenuates hypertension in a dose-dependent manner. We utilized a stable isotope of [15N]nitrite (15NO2-) as a source of nitrite to distinguish between endogenous nitrite and that exogenously administered and measured hemoglobin (Hb)-NO as an index of circulating NO in whole blood using electron paramagnetic resonance (EPR) spectroscopy. When 1 mg/kg Na15NO2 was orally administered to rats, an apparent EPR signal derived from Hb15NO (A(Z) = 23.4 gauss) appeared in the blood. The peak blood HbNO concentration occurred at the first measurement after intake (5 min) for treatment with 1 and 3 mg/kg (HbNO: 4.93 +/- 0.52 and 10.58 +/- 0.40 microM, respectively) and at 15 min with 10 mg/kg (HbNO: 38.27 +/- 9.23 microM). In addition, coadministration of nitrite (100 mg/l drinking water) with N(omega)-nitro-L-arginine methyl ester (L-NAME; 1 g/l) for 3 wk significantly attenuated the L-NAME-induced hypertension (149 +/- 10 mmHg) compared with L-NAME alone (170 +/- 13 mmHg). Furthermore, this phenomenon was associated with an increase in circulating HbNO. Our findings clearly indicate that orally ingested nitrite can be an alternative to L-arginine as a source of NO in vivo and may explain, at least in part, the mechanism of the nitrite/nitrate-rich Dietary Approaches to Stop Hypertension diet-induced hypotensive effects.
Koichiro Tsuchiya, Yoshiharu Takiguchi, Masumi Okamoto, Yuki Izawa, Yasuhisa Kanematsu, Masanori Yoshizumi and Toshiaki Tamaki : Malfunction of vascular control in lifestyle-related diseases : formation of systemic hemoglobin-nitric oxide Complex(HbNO) From Dietary Nitrite, Journal of Pharmacological Sciences, Vol.96, No.4, 395-400, 2004.
(要約)
Nitric oxide (NO) has many physiological functions. It is believed to be produced from L-arginine by nitric oxide synthase (NOS), and nitrite and nitrate are waste forms of it. By the way, nitrate and nitrite are abundant in vegetables and fruits, especially leafy vegetables and pickled vegetables. Orally-ingested nitrate is changed to nitrite by micro-organelles living in the hypopharynx area, and nitrite is expected to change to NO in the stomach due to its low pH. Indeed, some researchers reported that NO is produced in the gastric cavity, although few reports mentioned the physiological meanings of this NO formation. Therefore, we investigated whether the nitrite-derived NO can shift to the circulation and acts like NOS-derived NO does in tissues. We adopted a stable isotope of nitrite (15NO2-) in order to distinguish between the endogenous nitrite and the exogenously administered one and measured nitrosyl hemoglobin (HbNO) as an index of circulating NO using electron paramagnetic resonance spectroscopy. It appeared that the oral administration of 15N-nitrite formed the Hb15NO in rat blood and decreased the blood pressure of chronic L-NAME treated rats. Our findings suggest that the intake of nitrite (or nitrate)-rich foods such as vegetables and fruits would alter the systemic HbNO dynamism, resulting in the improvement of cardiovascular diseases.
Yoshiharu Takiguchi, Rie Ishihara, Mayumi Torii, Rinya Kato, Shin Kamihara and Toshihiko Uematsu : Hair analysis of flecainide for assessing the individual drug-taking behavior., European Journal of Clinical Pharmacology, Vol.58, No.2, 99-101, 2002.
(要約)
The concentration of flecainide in hair was measured to determine its value as an index of individual drug-taking history. Hair samples obtained from 15 patients treated with flecainide for more than 1 month were cut into 1-cm-long portions successively from its scalp end. The concentration of flecainide in each hair portion was measured using high-performance liquid chromatography. Flecainide was detected in the 1-cm-long hair portion at the scalp end in the concentration range of 38.0-411.9 ng x mg(-1), which significantly correlated with the area under the plasma flecainide concentration versus time curve. The axial centimeter-by-centimeter distribution of flecainide along the hair shaft well reflected the individual history of drug use. The present study suggests the usefulness of determining flecainide in hair to provide retrospective information on the individual drug-taking behavior qualitatively.
(キーワード)
Adult / Aged / Anti-Arrhythmia Agents / Area Under Curve / Chromatography, High Pressure Liquid / Female / Flecainide / Hair / Humans / Male / Middle Aged
Mayumi Torii, Yoshiharu Takiguchi, Miyako Izumi, Tokuya Fukushima and Masayuki Yokota : Carbapenem antibiotics inhibit valproic acid transport in Caco-2 cell monolayers., International Journal of Pharmaceutics, Vol.233, No.1-2, 253-256, 2002.
(要約)
The concomitant use of carbapenem antibiotics with valproic acid has been prohibited because carbapenems induced a decrease in plasma concentration of valproic acid in epileptic patients during valproic acid therapy. Our previous in vivo study in rats proposed that inhibition by carbapenem of the intestinal absorption of valproic acid might be a possible mechanism for the drug-drug interaction. To demonstrate the hypothesis, we examined the effects of imipenem and panipenem on intestinal transepithelial transport of valproic acid using Caco-2 cell monolayers. Imipenem and panipenem inhibited the transport of [14C]-valproic acid across the Caco-2 cell monolayers from apical-to-basolateral side in a concentration-dependent manner, although they had no effect on the uptake of [14C]-valproic acid by Caco-2 cells. The inhibition by the carbapenems of the valproic acid transport was found even when they were added to only the basolateral side. From these results, the carbapenems may inhibit the absorption of valproic acid at the basolateral membrane of intestinal epithelial cells, which contributes to the decrease in plasma concentration of valproic acid after oral administration.
Yoshiharu Takiguchi, Rie Ishihara, Rinya Kato, Shin Kamihara, Masayuki Yokota and Toshihiko Uemastu : Measurement of flecainide in hair as an index of drug exposure., Journal of Pharmaceutical Sciences, Vol.90, No.11, 1891-1896, 2001.
(要約)
We report a method for measuring the concentration of flecainide in hair. An animal study, in which flecainide (1, 5, and 10 mg/kg/day) was orally administered for 1, 2, and 3 weeks to pigmented rats, showed that flecainide concentration in rat hairs newly regrown after administration significantly correlated with both the daily dose and the dosing period. The part of hair containing flecainide continued to grow upward, retaining the drug within the hair structure that had been formed at the time of drug exposure. Flecainide was also determined in human scalp hairs collected from patients treated with flecainide. The drug content of white hairs was much less than that black hairs collected from the same rats and subjects, suggesting the determinant effect of hair pigment on flecainide accumulation in hair. These findings suggest that the analysis of flecainide in hair may be useful for assessing exposure to drug qualitatively.
(キーワード)
Animals / Anti-Arrhythmia Agents / Dose-Response Relationship, Drug / Flecainide / Hair / Humans / Male / Rats / Research Design
Seiko Ida, Masayuki Yokota, Makoto Ueoka, Kenji Kiyoi and Yoshiharu Takiguchi : Mild to severe lithium-induced nephropathy models and urine N-acetyl-β-d-glucosaminidase in rats., Methods and Findings in Experimental and Clinical Pharmacology, Vol.23, No.8, 445-448, 2001.
(要約)
Long-term treatment with lithium induces functional and/or structural disturbances in the kidneys. However, no procedure has been established for the early diagnosis of lithium intoxication. In this study, we prepared mild to severe lithium-induced nephropathy rat models and examined the usefulness of urine N-acetyl-beta-D-glucosaminidase (NAG) for the early diagnosis of lithium-induced renal insufficiency. Lithium was administered by repeated intraperitoneal injection (1, 2 and 4 mEq/kg/day for 10 days). We also measured the plasma creatinine and paraaminohippuric acid (PAH) clearance, and observed renal histological changes. Lithium pretreatment elevated the plasma creatinine level and decreased PAH clearance in a dose-dependent manner. The NAG level in the lithium 4 mEq/kg group was very high. The levels in the lithium 1 mEq/kg and 2 mEq/kg groups were almost the same and were higher than the control group. A histological examination of the kidney revealed glomerular congestion and/or atrophy and tubular expansion in all of the groups except the control group. These histological changes were dose-dependent. In conclusion, urine NAG may be useful in the early diagnosis of renal side effects caused by lithium therapy. When the urine NAG level becomes high in a patient taking lithium for bipolar disorder, the physician may need to consider lithium-induced renal insufficiency.
Mayumi Torii, Yoshiharu Takiguchi, Fumiko Saito, Miyako Izumi and Masayuki Yokota : Inhibition by carbapenem antibiotic imipenem of intestinal absorption of valproic acid in rats., The Journal of Pharmacy and Pharmacology, Vol.53, No.6, 823-829, 2001.
(要約)
The concomitant use of carbapenem antibiotics with valproic acid has been prohibited because panipenem induced a decrease in plasma concentration of valproic acid in epileptic patients during valproic acid therapy. To clarify the possible mechanism of the carbapenem-valproic acid interaction, we investigated the effect of imipenem on the pharmacokinetic behaviour of valproic acid in rats. Co-administration of imipenem (30 mg kg(-1), i.v.) induced a decrease in the peak plasma concentration of valproic acid after oral administration. However, the imipenem-induced decrease in plasma concentrations of valproic acid was not observed within 60 min after intravenous injection of valproic acid. By utilizing in-situ vascular and luminal perfused small intestine, it was confirmed that absorption of valproic acid from the luminal to the vascular perfusate was decreased in the presence of imipenem (0.5 mM) in the vascular perfusate. The everted gut sac method was used to determine the effect of imipenem on active transport of valproic acid. The accumulation of valproic acid on the serosal side of the intestinal sac against the concentration gradient was reduced by lactic acid that inhibits the carrier-mediated transport of valproic acid across the intestinal brush-border membrane. However, imipenem did not affect the active transport of valproic acid. Therefore, the inhibition by imipenem of valproic acid absorption may be caused by a mechanism different from that of lactic acid. In conclusion, imipenem inhibits the intestinal absorption of valproic acid, which contributes to the decrease in plasma concentration of valproic acid after oral administration.
Hiroyuki Matsuno, Osamu Kozawa, Masayuki Niwa, Akira Abe, Yoshiharu Takiguchi and Toshihiko Uematsu : Characterization of simple and reproducible vascular stenosis model in hypercholesterolemic hamsters., Lipids, Vol.36, No.5, 453-460, 2001.
(要約)
The importance of low-density lipoprotein (LDL) in the etiology of atherosclerosis is well recognized. We have established a reproducible stenosis model in hypercholesterolemic hamsters, and the process of arterial stenosis by thrombus or neointima was studied and compared with that in normal hamsters. The level of plasma LDL was 4.6 times higher in hamsters fed a high-cholesterol diet than in hamsters fed normal food. Endothelial injury in right common carotid arteries was induced using a modified catheter. Arterial blood flow was monitored continuously using a Doppler flow probe. Arterial patency after the initiation of injury in high-cholesterol hamsters was significantly changed as compared with that of normal hamsters. Neointima was observed 2 wk after the vascular injury. The neointimal area of high-cholesterol hamsters was significantly larger than that of normal hamsters. To characterize the stenosis in hypercholesterolemic hamsters, we measured platelet aggregation, thrombin time, activated partial thromboplastin time, and proliferating smooth muscle cells (SMC) in vitro and in vivo. The half-maximal inhibitory concentration value for platelet aggregation induced by thrombin or collagen, the DNA synthesis stimulated by platelet-derived growth factor (PDGF)-BB, and 5-bromo-2-deoxy-uridine labeling indices (proliferating index of SMC in vivo) in high-cholesterol hamsters were each significantly higher than the comparable value from normal hamsters. However, specific binding of PDGF-BB in SMC was not different between the two types of hamsters. Furthermore, we investigated the inhibitory effects of probucol or losartan on neointima formation using this model. Probucol, but not losartan, significantly reduced the neointimal area in hypercholesterolemic hamsters. These findings indicated that high levels of plasma LDL strongly contributed to the development of thrombus and neointima formation via both up-regulation of platelet aggregation and the enhancement of SMC proliferation. This stenosis model may be useful for the investigation of hypercholesterolemia-associated cardiovascular diseases.
Hiroshi Yoshioka, Seiko Ida, Masayuki Yokotra, Ayako Nishimoto, Sachiko Shibata, Akiko Sugawara and Yoshiharu Takiguchi : Effects of litium on the pharmacokinetics of valproate in rats., The Journal of Pharmacy and Pharmacology, Vol.52, No.3, 297-301, 2000.
(要約)
Combined treatment with lithium and valproate has been used for bipolar disorder. However, the studied interaction between these two drugs has not been fully investigated. We therefore examined the effects of lithium on the pharmacokinetics (plasma disappearance, metabolism and urinary excretion) of valproate in rats. Lithium (2 mEq kg(-1)) was administered intraperitoneally twice a day for ten days. Plasma disappearance curves of valproate (50 mg kg(-1), i.v.), valproate-metabolizing activities of UDP-glucuronosyltransferase (UGT) and cytochrome P450 (CYP) in liver microsomes and urinary excretion of free valproate and valproate-glucuronide were examined. The metabolizing activity of UGT and CYP were determined by enzyme assays and a fluorescence polarization immunoassay system. Urinary valproate-glucuronide was obtained using this system by subtracting the free level from total level, which was determined after deconjugating the sample with heat and NaOH. The half-life of plasma disappearance of valproate was 25% reduced by lithium pretreatment (0.428 +/- 0.031 h with repeated lithium pretreatment vs 0.578 +/- 0.062 h for controls). The valproate-metabolizing activity of UGT and CYP were not altered by lithium although lithium increased the urinary excretion of valproate-glucuronide. In conclusion, lithium pretreatment causes a decrease in plasma valproate levels and an increase in urinary excretion of valproate-glucuronide in rats.
Seiko Ida, Masayuki Yokota, Hiroshi Yoshioka and Yoshiharu Takiguchi : Single exposure to gasoline or ether reduces cytochrom P-450 activities without affecting UDP-glucuronosyltransferase activity in rat liver., Journal of Occupational Health, Vol.42, 84-85, 2000.
Yoshikazu Matsumura, Masayuki Yokota, Hiroshi Yoshioka, Sachiko Shibata, Seiko Ida and Yoshiharu Takiguchi : Acute effects of griseofulvin on the pharmacokinetics of warfarin in rats., The Journal of International Medical Research, Vol.27, No.4, 167-175, 1999.
(要約)
It has been reported that prothrombin time (PT), which is prolonged by warfarin, is reduced when patients on warfarin also take griseofulvin repeatedly. We investigated the cause of the drug interaction and the initial effects of griseofulvin on warfarin pharmacokinetics. Total cytochrome P-450, and the activities of aminopyrine N-demethylase, aniline p-hydroxylase and 7-ethoxycoumarin O-deethylase, after repeated administration of griseofulvin (100 mg/kg orally daily for 5 days) were examined. Acute effects of single doses of griseofulvin (100 mg/kg) on coagulation activity (prothrombin time) and warfarin pharmacokinetics after administration of warfarin were also studied. Repeated administration of griseofulvin induced warfarin-metabolizing enzymes. In contrast, a single administration of griseofulvin increased prothrombin time and serum warfarin concentrations. The activity of a warfarin-metabolizing enzyme (7-ethoxycoumarin O-deethylase) was reduced when griseofulvin was added to rat liver microsomes. The results suggest that reduced warfarin action after repeated administration of griseofulvin may be due to induction of warfarin-metabolizing enzymes, but that there is also an initial increase in warfarin action.
(キーワード)
Animals / Anticoagulants / Cytochrome P-450 Enzyme System / Drug Interactions / Griseofulvin / Isoenzymes / Male / Microsomes, Liver / Prothrombin Time / Rats / Rats, Wistar / Warfarin
Hiroyuki Matsuno, Osamu Kozawa, Masayuki Niwa, Kumiko Tanabe, Katsuhiko Ichimaru, Yoshiharu Takiguchi, Masayuki Yokota, Hideharu Hayashi and Toshihiko Uematsu : Multiple inhibition of platelet activation by aurintricarboxylic acid prevents vascular stenosis after endothelial injury in hamster carotid artery., Thromb.Haemost., Vol.79, 865-871, 1998.
34.
Osamu Kozawa, Toshihiko Uematsu, Hiroyuki Matsuno, Masayuki Niwa, Yoshiharu Takiguchi, Syouzou Matsumonot, Masahiko Minamoto, Yoshito Niida, Masahiro Yokokawa, Satoru Nagashima and Mitsutaka Kanamaru : Pharmacokinetics and safety of a new parenteral carbapenem antibiotic, biapenem (L-627), in eldery subjects., Antimicrobial Agents and Chemotherapy, Vol.42, 1433-1436, 1998.
35.
Masamitsu Shimazawa, Yoshiharu Takiguchi, Kazuo Umemura, Kazunao Kondo and Mitsuyoshi Nakashima : Antithrombotic effects in a rat model of aspirin-insensitive arterial thrombosis of desethyl KBT-3022, the main active metabolite of a new antiplatelet agent, KBT-3022., European Journal of Pharmacology, Vol.328, 183-189, 1997.
36.
Masamitu Shimazawa, Yoshiharu Takiguchi, Kazuo Umemura and Mitsuyoshi Nakashima : Antithrombotic effects of KBT-3022, a novel antiplatelet agent, in an arterial thrombosis model in the guinea-pig., Drug Develop.Res., Vol.40, 217-222, 1997.
37.
Yoshiharu Takiguchi and Keizo Sogabe : The selective endothelin ETA receptor antagonist FR139317 inhibits neointimal thickening in the rat., European Journal of Pharmacology, Vol.309, No.1, 59-62, 1996.
38.
Koichiro Wada, Kazuo Umemura, Hiroshi Nishiyama, Abby R Saniabadi, Yoshiharu Takiguchi, Minoru Nakano and Mitsuyoshi Nakashima : A chemiluminescent detection of superoxide radical produced by adherent leucocyte to the subendothelium following thrombolysis: studies with a photochemically induced thrombosis model in the guinea pig femoral artery., Atherosclerosis, Vol.122, No.2, 217-224, 1996.
(要約)
Reocclusion following thrombolysis is a major limitation of thrombolytic therapy with recombinant tissue-type plasminogen activator (rt-PA) because denuded vessel wall exposed to blood following thrombolysis is a favourable surface for platelet and leucocyte deposition. We have applied a chemiluminescence technique to detect superoxide radical (0(-2)) produced by leucocytes adherent to the femoral artery 24 h after photochemically induced thrombogenesis in the guinea pig in vivo and subsequent thrombolysis by rt-PA. Intravenous administration of MCLA, a specific chemiluminescence reagent for detecting O(-2), markedly increased photon emission. the photon emission was markedly potentiated by phorbol myristate acetate and was suppressed by superoxide dismutase. Reocclusion 24 h after rt-PA induced thrombolysis was observed in 10 of 16 animals. Histological observations revealed extensive polymorphonuclear leucocytes adherent to the vessel wall at the site of thrombogenesis and thrombolysis. A higher level of 0(-2) could be detected from the arteries in which thrombolysis was induced compared with those without thrombolysis. Further, the level 0(-2) detected was greater in reoccluded arteries compared with those in which reflow was established. These observations suggest that 0(-2) is produced by adherent leucocytes at the site of thrombolysis and that leucocytes are involved in reocclusion after thrombolysis.
Yoshiharu Takiguchi, Masamitsu Shimazawa and Mitsuyoshi Nakashima : A comparative study of the antithrombotic effect of aurintricarboxylic acid on arterial thrombosis in rats and guinea-pigs, British Journal of Pharmacology, Vol.118, No.7, 1633-1638, 1996.
40.
Yoshiharu Takiguchi, Fumitoshi Asai, Koichiro Wada and Mitsuyoshi Nakashima : Comparison of antithrombotic effects of GPIIb-IIIa receptor antagonist and TXA2 receptor antagonist in the guinea-pig thrombosis model:Possible role of TXA2 in reocclusion after thrombolysis., Thromb.Haemostas., Vol.73, 683-688, 1995.
41.
Yoshiharu Takiguchi, Tomoko Nagano, Masahiko Ikeda and Mitsuyoshi Nakashima : Early administration of YT-146, an adenosine A2 receptor agonist, inhibits neointimal thickening after rat femoral artery endothelium injury., European Journal of Pharmacology, Vol.281, 205-207, 1995.
42.
Yoshiharu Takiguchi, Fumitoshi Asai, Koichiro Wada, Hideya Hayashi and Mitsuyoshi nakashima : Antithrombotic effect of a novel recombinant hirudin analogue, CX-397, in a rat arterial thrombosis model., British Journal of Pharmacology, Vol.116, 3056-3060, 1995.
Hiroshi Nishiyama, kazuo Umemura, Abby.R Saniabadi, Yoshiharu Takiguchi, Toshihiko Uematsu and Mitsuyoshi Nakashima : Enhancement of thrombolytic efficacy of tissue-type plasminogen activator by adjuvants in the guinea pig thrombosis model., European Journal of Pharmacology, Vol.264, 191-198, 1994.
45.
Koichiro Wada, Abby.R Saniabadi, Kazuo Umemura, Yoshiharu Takiguchi and Mitsuyoshi Nakasima : UV-dependent quinolone-induced human erythrocyte membrane lipid peroxidation:Studies on the phototoxicity of Y-26611, a new quinolone derivative., Pharmacology and Toxicology, Vol.74, 240-243, 1994.
46.
Hiroyuki Matsuno, Toshihiko Uematsu, Kazuo Umemura, Yoshiharu Takiguchi, Yoshihiro Asai and Mitsuyoshi Nakashima : A simple and reproducible cerebral thrombosis model in rats induced by a photochemical reaction and the effect of a plasminogen-plasminogen activator chimera in this model., Journal of Pharmacological and Toxicological Methods, Vol.29, No.3, 165-173, 1993.
(要約)
In this study a new model of cerebral ischemia, based on a middle cerebral artery (MCA) thrombosis in rats is described. Furthermore, the effect of the novel plasminogen activator (SUN9216), a plasminogen-plasminogen activator chimera, comprising the fibrin kringle 1 domain of a plasminogen, and the two kringles, and the serine protease domains of wild-type tissue plasminogen activator (t-PA), including a modification of the mannose glycosylation site on the kringle 1 of t-PA (PK1de1FE1X), was studied in this model. In the newly described model of thrombotic cerebral ischemia, an occlusive thrombus occurred usually within 8 min in the MCA as a consequence of an endothelial injury subsequent to a photochemical reaction between a systemically administered photosensitive dye (rose bengal) and a transillumination of the MCA with a high-intensity green light with a wavelength of 540 nm. The study was quantitated by means of pathological examination of the MCA and the brain. A platelet-rich thrombus was observed in the MCA using electron microscopical analysis based on ion beam bombardment. At 24 hr after induction of the thrombus, the brain was removed from 13 control animals, nine coronal sections were stained from each brain with triphenyltetrazoliumchloride (TTC), and the ischemic area was quantitated. A constant area of infarction was observed in the cortex and the lateral part of the basal ganglia. In a second group (n = 8), at 1 or 8 weeks after induction of the thrombosis in the MCA, the coronal sections were stained with hematoxylin and eosin.(ABSTRACT TRUNCATED AT 250 WORDS)
Yoshiharu Takiguchi, Koichiro Wada and Mitsuyoshi Nakashima : Hemodynamic effects on thrombogenesis and platelet aggregation in spontaneously hypertensive rats., Clin.Exp.Hypertension, Vol.15, 197-208, 1993.
48.
Yoshihiro Hirata, Yoshiharu Takiguchi, Koichiro Wada, Hiroyuki Matsuno, Kazuo Umemura, Toshihiko Uematsu and Mitsuyoshi Nakashima : Roles of platelet-activating factor, thromboxane A2, ADP and thrombin in thrombogenesis in the guinea pig., European Journal of Pharmacology, Vol.231, 421-425, 1993.
49.
Koichiro Wada, Yoshiharu Takiguchi and Mitsuyoshi Nakashima : Changes in platelet aggregation in whole blood, plasma and washed platelets in streptozotocin-induced diabetic rats: Time-dependent change in the antiaggregatory activity of diabetic rat plasma., Platelets, Vol.4, No.5, 280-284, 1993.
(要約)
Time-dependent changes in platelet aggregation in whole blood, platelet-rich plasma (PRP) and washed platelets were studied in streptozotocin-induced diabetic rats. Collagen-induced aggregation of whole blood and PRP from diabetic rats were significantly reduced within 8 weeks after induction of diabetes, although that in washed platelets were increased from 8 weeks. Plasma from diabetic rats within 8 weeks attenuated platelet aggregation, whereas diabetic plasma at 12 weeks showed no inhibitory effect. Insulin treatment normalized aggregation in whole blood and PRP and abolished the antiaggregatory activity of diabetic plasma. These results suggest the plasma antiaggregating activity appears in the early stage of diabetes, which may contribute to the hypoaggregation in whole blood and PRP. The inhibitory activity disappeared in the later stage. Plasma factor(s) accounting for the antiaggregatory effect of diabetic plasma has not yet characterized.
Yoshinori Hirata, Kazuo Umemura, Yoshiharu Takiguchi, Toshihiko Uematsu and Mitsuyoshi Nakashima : A thrombosis model for evaluating thrombolytic agents in the guinea-pig:comparison of t-PA, scu-PA and a novel thrombolytic agent, staphylokinase, on thrombolytic activity., Blood Coagulat.Fibrinol., Vol.4, 569-575, 1993.
51.
Yoshiharu Takiguchi, Yoshihiro Hirata, Koichiro Wada and Mitsuyoshi Nakashima : Arterial thrombosis model with photochemical reaction in guinea-pig and its property., Thrombosis Research, Vol.67, No.4, 435-445, 1992.
(要約)
We have already developed an arterial thrombosis model in the rat femoral artery which utilized photochemical reaction between systemically injected rose bengal and transillumination of a green light with 540 nm wave length from the outside of the vessel. In the present study, we applied this model to guinea-pigs in order to produce a more suitable thrombus model for evaluation of antithrombotic drugs which act on the prostaglandin cascade. In the guinea-pigs, the irradiated femoral artery was completely occluded in 7 min after the injection of rose bengal (10 mg/kg) in a similar manner to the rats. The processes of primary endothelial injury and the subsequent formation of thrombus during this manipulation were observed by the electron microscopy. Pretreatment with aspirin and Y-20811, a thromboxane synthetase inhibitor, significantly prolonged the time required for occlusion in the guinea-pigs, while these drugs were ineffective in the rats. The antithrombotic effect of vapiprost, a thromboxane A2 receptor antagonist, was more pronounced in the guinea-pigs than the rats. In conclusion, this model in guinea-pigs is more suitable for evaluating antithrombotic drugs, particularly, the action of which is exerted involving the prostaglandin cascade.
hiroyuki Matsuno, Toshihiko Uematsu, Kazuo Umemura, Yoshiharu Takiguchi, Koichiro Wada and Mitsuyoshi Nakashima : Effects of vapiprost, a novel thromboxane receptor antagonist, on thrombus formation and vascular patency after thrombolysis by tissue-type plasminogen activator., British Journal of Pharmacology, Vol.106, 533-538, 1992.
53.
Yoshiharu Takiguchi, Koichiro Wada and Mitsuyoshi Nakashima : Comparison of the inhibitory effects of the TXA2 receptor antagonist, vapiprost, and other antiplatelet drugs on arterial thrombosis in rats:Possible role of TXA2., Thromb.Haemostas., Vol.68, 460-463, 1992.
54.
Yoshiharu Takiguchi, Koichiro Wada and Mitsuyoshi Nakashima : Effect of aldose reductase inhibitor on the inhibition of platelet aggregation induced by diabetic rat plasma., European Journal of Pharmacology, Vol.215, 289-291, 1992.
55.
R.P Hof, Yoshiharu Takiguchi, J Nussberger, A Hof, M Klay, T Peters, R Zelis and H.R Brunner : Baroreflex and atrial natriuretic factor concentration correlate with myocardial infarct size and predict early death in rabbits:Implications for drug studies., Journal of Cardiovascular Pharmacology, Vol.18, No.3, 361-368, 1991.
(要約)
The severity of myocardial infarction (MI) and its functional consequences are difficult to assess in small animals. We searched for criteria to achieve such an assessment in rabbits 1 week after MI. Thirteen large mongrel rabbits (3-4 kg) were anesthetized with pentobarbitone for ligating a branch of the circumflex coronary artery and 7 rabbits were subject to a sham operation without ligation. All sham-operated rabbits and 12 MI animals survived for 1 week, when blood was obtained for biochemical analyses and the baroreflex was tested. Six animals survived to the third week (survivors) and six died earlier (nonsurvivors). The MI size, measured immediately after death, was 42 +/- 3% of the left ventricular mass in nonsurvivors and 20 +/- 7% in survivors. The plasma atrial natriuretic factor (ANF) concentration was correlated linearly with MI size (r = 0.77) over the whole range of infarct sizes and, like the MI size itself, was associated with the risk of early death (critical limit: 80 pM). Plasma renin activity and catecholamines yielded less prognostic information. The baroreflex control of the heart rate (tested using phenylephrine and nitroprusside) of nonsurvivors was severely impaired and the slopes correlated with MI size (r = 0.90 for phenylephrine and r = 0.67 for nitroprusside). The plasma ANF concentration and the baroreflex both accurately reflected MI size and also correctly classified 11/12 rabbits into survivors and nonsurvivors. An ANF- and baroreflex-based stratification of animals for future studies on therapeutic interventions after MI will reduce the number of animals required by at least 65%, making such studies far more feasible than in the past.
Yoshiharu Takiguchi, Koichiro Wada, Hiroyuki Matsuno and Mitsuyoshi Nakashima : Effect of diabetes on photochemically induced thrombosis in femoral artery and platelet aggregation in rats., Thrombosis Research, Vol.63, No.4, 445-456, 1991.
(要約)
Effect of diabetes on thrombogenesis was examined by using a thrombus model with photochemical reaction in the rat femoral artery. In streptozotocin-induced diabetic rats for 8 weeks, the formation of thrombus following endothelial injury was significantly slower than that in non-diabetic rats. Insulin treatment normalized the abnormality of thrombogenesis. Aggregation in washed platelets from rats with diabetes was enhanced. However, platelet aggregation in whole blood was reduced in diabetic rats, and plasma from diabetic rats attenuated platelet aggregation. These results suggest that plasma factor(s) and/or other blood cells modify the hyperaggregability of platelets per se in vivo in diabetic rats. Treatment with insulin improved the aggregation in whole blood and washed platelets. In conclusion, diabetes induces the prolongation of thrombogenesis in the rat femoral artery. Hypoaggregability of whole blood is likely to be partly involved in the abnormal thrombogenesis.
Naoshi Yamazaki, Makiko Shinomiya, Hironobu Ike, Yasuo Shinohara, Noriaki Minakawa, Kouji Itou and Yoshiharu Takiguchi : Use of modified U1 small nuclear RNA for improved formation of properly spliced mRNA encoding human cathepsin A from the gene having an IVS7 +3a>g mutation, The 43rd FEBS Congress, Praha, Jul. 2018.
2.
Yoshiharu Takiguchi : Yoshiharu Takiguchi, Shin-ichi Tani, Keisuke Furuta, Naoshi Yamazaki. Implication of endogenous lysophosphatidic acid in intimal thickening in rat injured artery.Implication of endogenous lysophosphatidic acid in intimal thickening in rat injured artery. 18th World Congress of Basic and Clinical Pharmacology, Kyoto, Jul. 2018.
3.
Naoshi Yamazaki, Yasuo Shinohara, Kouji Itou, Noriaki Minakawa and Yoshiharu Takiguchi : Rescue of mutation-induced exon 7 skipping in human Cathepsin A by using modified U1 small nuclear RNA, 2016 ASCB Annual Meeting, San Francisco, Dec. 2016.
4.
Shima Sawako, Takenori Yamamoto, Yasuo Shinohara and Yoshiharu Takiguchi : Induction of mitochondrial permeability transition by dequalinium, 40th FEBS Congress, Berlin, Jul. 2015.
5.
Kuwahara Kana, Harada Kazuki, Yamagoshi Ryohei, Yoshiharu Takiguchi, Takenori Yamamoto and Yasuo Shinohara : Effects of employment of distinct strategies to capture antibody on antibody delivery into cultured cells, 40th FEBS Congress, Berlin, Jul. 2015.
6.
Takenori Yamamoto, Ito Mika, Kageyama Keita, Kuwahara Kana, Kikuji Yamashita, Yoshiharu Takiguchi, Seiichiro Kitamura, Hiroshi Terada and Yasuo Shinohara : Mastoparan causes mitochondrial permeability transition not by interacting with specific proteins, but by interacting with the phospholipid phase, The American Society for Cell Biology 2014, Philadelphia, Dec. 2014.
7.
Noriko Saito-Tarashima, Kojima Takamitsu, Hashimoto Yosuke, Kazuhiro Furukawa, Naoshi Yamazaki, Hiroshi Kiwada, Tatsuhiro Ishida, Noriaki Minakawa and Yoshiharu Takiguchi : A novel approach of gene suppression using an intelligent shRNA expressing device (iRed), 9th Annual Meeting of the Oligonucleotide Therapeutics Society, Naples(Italy), Oct. 2013.
8.
Y. Kikuchi, Naoshi Yamazaki, Yoshiharu Takiguchi and Noriaki Minakawa : Gene silencing by 2'-modified-4'-thio oligonucleotides via U1i machinery, 第39回国際核酸化学シンポジウム, Nov. 2012.
9.
Koichiro Tsuchiya, Yuya Horinouchi, Yasuhisa Kanematsu, Shinji Abe, Hideki Ohnishi, Soichiro Tajima, Keisuke Ishizawa, Toshiaki Tamaki and Yoshiharu Takiguchi : Production of nitrosonifedipine radical from nifedipine and its antioxidative activity in cultured cells, 13th annual meeting of society of free radical and biology of medicine, Denver, Nov. 2006.
10.
Koichiro Tsuchiya, Yasuhisa Kanematsu, Keisuke Ishizawa, Shinji Abe, Hideki Ohnishi, Soichiro Tajima, Kazuyoshi Kawazoe, Yoshiharu Takiguchi and Toshiaki Tamaki : Dietary nitrite is an alternative source of NO in vivo, International Society for Radical Research 13th Biennial Congress, Davos, Switzerland, Aug. 2006.
11.
Soichiro Tajima, Koichiro Tsuchiya, Hideki Ohnishi, Yasuhisa Kanematsu, Masanori Yoshizumi, Toshiaki Tamaki, Mason P. Ronald and Yoshiharu Takiguchi : Immunochemical Dection of Thioredoxin-Derived Radicals Formed by Reaction with Hydrogen Peroxide, EPR 2005, Columbus, OH, Sep. 2005.
Naoshi Yamazaki, Makiko Shinomiya, Hironobu Ike, Yasuo Shinohara, Noriaki Minakawa, Kouji Itou and Yoshiharu Takiguchi : Use of modified U1 small nuclear RNA for improved formation of properly spliced mRNA encoding human cathepsin A from the gene having an IVS7 +3a>g mutation, FEBS Open Bio, Vol.8, No.Supplement 1, ShT.35-1, Jul. 2018.