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Sakura, Japan

Nishimura S.,Kinki University | Nishimura S.,Clinical Research Institute for Endocrine and Metabolic Diseases | Ishikura H.,Fukuoka University | Matsunami M.,Kinki University | And 7 more authors.
Life Sciences | Year: 2010

Aims: Proteinase-activated receptor-2 (PAR2) and transient receptor potential vanilloid-1 (TRPV1) are co-localized in the primary afferents, and the trans-activation of TRPV1 by PAR2 activation is involved in processing of somatic pain. Given evidence for contribution of PAR2 to pancreatic pain, the present study aimed at clarifying the involvement of TRPV1 in processing of pancreatic pain by the proteinase/PAR2 pathway in mice. Main methods: Acute pancreatitis was created by repeated administration of cerulein in conscious mice, and the referred allodynia/hyperalgesia was assessed using von Frey filaments. Injection of PAR2 agonists into the pancreatic duct was achieved in anesthetized mice, and expression of Fos in the spinal cord was determined by immunohistochemistry. Key findings: The established referred allodynia/hyperalgesia following cerulein treatment was abolished by post-treatment with nafamostat mesilate, a proteinase inhibitor, and with capsazepine, a TRPV1 antagonist, in mice. Injection of trypsin, an endogenous PAR2 agonist, or SLIGRL-NH2, a PAR2-activating peptide, into the pancreatic duct caused expression of Fos protein in the spinal superficial layers at T8-T10 levels in the mice. The spinal Fos expression caused by trypsin and by SLIGRL-NH2 was partially blocked by capsazepine, the former effect abolished by nafamostat mesilate. Significance: Our data thus suggest that the proteinase/PAR2/TRPV1 cascade might impact pancreatic pain, in addition to somatic pain, and play a role in the maintenance of pancreatitis-related pain in mice. © 2010 Elsevier Inc.

Kobayashi K.,Chiba University | Kajiwara E.,Chiba University | Ishikawa M.,Chiba University | Mimura H.,Chiba University | And 5 more authors.
Drug Metabolism and Pharmacokinetics | Year: 2013

Treatment with benzbromarone (BBR), a potent uricosuric drug, can be associated with liver injury. Recently, we reported that culture of human hepatocellular carcinoma FLC-4 cells on micro-space cell culture plates could increase the functional expression of drug-metabolizing enzymes including CYP3A4 and CYP2C9, which are involved in 1 ́-hydroxylation and 6-hydroxylation of BBR, respectively. Therefore, we examined whether BBR and its two metabolites (1 ́-hydroxy BBR and 6-hydroxy BBR) have cytotoxic effects in FLC4 cells cultured on micro-space cell culture plates. The present study showed that BBR and 1 ́-hydroxy BBR, but not 6-hydroxy BBR, have cytotoxic effects in cells cultured on micro-space cell culture plates. BBR-induced cytotoxicity was decreased by CYP3A inhibitors (itraconazole and ketoconazole), an Nrf2 activator (tert-butylhydroquinone) and a GSH precursor (N-acetyl-L-cystein). In contrast, BBR-induced cytotoxicity was increased by a GSH biosynthesis inhibitor (buthionine sulfoximine) and an inhibitor of NAD(P)H quinone oxidoreductase 1 (dicoumarol). These results suggested that metabolic activation of 1 ́-hydroxy BBR via CYP3A, formation of quinone metabolites and the decrease in GSH levels were involved in the BBR-induced cytotoxicity observed in FLC4 cells cultured on micro-space cell culture plates. © 2013 by the Japanese Society for the Study of Xenobiotics (JSSX).

Saito S.,Gifu University | Oikawa T.,Torii Pharmaceutical Co. | Taniguchi K.,Kitasato University | Taniguchi K.,Iwate University
Tissue and Cell | Year: 2010

The squamates are composed of many taxa, among which there is morphological variation in the vomeronasal organ (VNO). To elucidate the evolution of chemoreception in squamate reptiles, morphological data from the VNO from a variety of squamate species is required. In this study, the morphology of the VNO of the grass lizard Takydromus tachydromoides was examined using light and electron microscopy. The VNO consists of a pair of dome-shaped structures, which communicate with the oral cavity. There are no associated glandular structures. Microvilli are present on the apical surfaces of receptor cells in its sensory epithelium, as well as on supporting cells, and there are centrioles and ciliary precursor bodies on the dendrites. In addition to ciliated cells and basal cells in the non-sensory epithelium, there is a novel type of non-ciliated cell in T. tachydromoides. They have constricted apical cytoplasm and microvilli instead of cilia, and are sparsely distributed in the epithelium. Based on these results, the variation in the morphology of the VNO in scincomorpha, a representative squamate taxon, is discussed. © 2010 Elsevier Ltd.

Matsumura K.,Torii Pharmaceutical Co.
Yakugaku Zasshi | Year: 2015

The control of the serum phosphorus (P) level in chronic kidney disease patients is important because elevated serum P levels are associated with progression of vascular calcification and increased mortality in these patients. In 2014, a novel phosphate binder, ferric citrate hydrate (Riona®), became available for the treatment of hyperphosphatemia in Japan, the first country to approve this medication. Ferric citrate hydrate, which relies upon the potent phosphate-binding capacity of ferric iron, inhibits P absorption by forming complexes between ferric iron and dietary phosphate in the gut. The active pharmaceutical ingredient in ferric citrate hydrate provides a larger specific surface area and higher water solubility; therefore, it is expected to have greater e‹cacy in terms of its phosphate-binding capacity. In clinical trials, ferric citrate hydrate significantly reduced the serum phosphate level and effectively maintained serum P concentrations throughout the duration of the trials. Moreover, in one clinical trial, ferric citrate hydrate significantly decreased levels of fibroblast growth factor-23 (FGF-23) in nondialysis patients. FGF-23 is an endocrine hormone that increases urinary phosphate excretion to maintain serum P at the proper level. A portion of the iron from ferric citrate hydrate is absorbed and transported throughout the body as transferrin-bound iron, where it is used for the synthesis of hemoglobin, enzymes, and others. Although safer and more effective phosphate binders are expected in the future, ferric citrate hydrate will become a new approach for the treatment of hyperphosphatemia. © 2015 The Pharmaceutical Society of Japan.

Shinohara M.,CLEA Japan Inc. | Oikawa T.,Torii Pharmaceutical Co. | Sato K.,Nihon University | Kanazawa Y.,Jichi Medical University
Open Diabetes Journal | Year: 2011

In order to examine the effect of sex hormones on diabetic pathogenesis in female Spontaneously Diabetic Torii (SDT) rats, we performed oophorectomy on female SDT rats, administered female hormones after the oophorectomy, and measured body weight changes, plasma glucose concentration, and pancreatic histopathology. At 26 weeks of age, the body weight was significantly heavier in the oophorectomized group and significantly lighter in the estradiol benzoate (EB) administration group than in the sham-operated control group. Although glucose concentration did not significantly change in the oophorectomized group, it was significantly lower in the EB administration group than in both control and the oophorectomized group. Severe histopathological change was observed in the oophoretomized group but not in the EB administration group. Thus, EB blocked weight gain and pancreatic islet change that was induced by oophoretomy and it also lowered glucose concentration. These results suggest that estrogen plays a preventive role for diabetic pathogenesis in female SDT rats. © Shinohara et al.

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