Drug receptor function and its regulation

科学研究費補助金研究成果報告書研究種目: 総合研究(A)研究期間: 1993～1995課題番号: 05304026研究代表者: 戸田 昇（滋賀医科大学・医学部・教授

Involvement of S-adenosylmethionine-dependent halide/thiol methyltransferase (HTMT) in methyl halide emissions from agricultural plants: isolation and characterization of an HTMT-coding gene from Raphanus sativus (daikon radish)

<p>Abstract</p> <p>Background</p> <p>Biogenic emissions of methyl halides (CH₃Cl, CH₃Br and CH₃I) are the major source of these compounds in the atmosphere; however, there are few reports about the halide profiles and strengths of these emissions. Halide ion methyltransferase (HMT) and halide/thiol methyltransferase (HTMT) enzymes concerning these emissions have been purified and characterized from several organisms including marine algae, fungi, and higher plants; however, the correlation between emission profiles of methyl halides and the enzymatic properties of HMT/HTMT, and their role in vivo remains unclear.</p> <p>Results</p> <p>Thirty-five higher plant species were screened, and high CH₃I emissions and HMT/HTMT activities were found in higher plants belonging to the Poaceae family, including wheat (<it>Triticum aestivum </it>L.) and paddy rice (<it>Oryza sativa </it>L.), as well as the Brassicaceae family, including daikon radish (<it>Raphanus sativus</it>). The in vivo emission of CH₃I clearly correlated with HMT/HTMT activity. The emission of CH₃I from the sprouting leaves of <it>R. sativus</it>, <it>T. aestivum </it>and <it>O. sativa </it>grown hydroponically increased with increasing concentrations of supplied iodide. A gene encoding an <it>S</it>-adenosylmethionine halide/thiol methyltransferase (HTMT) was cloned from <it>R. sativus </it>and expressed in <it>Escherichia coli </it>as a soluble protein. The recombinant <it>R. sativus </it>HTMT (RsHTMT) was revealed to possess high specificity for iodide (I^-), bisulfide ([SH]^-), and thiocyanate ([SCN]^-) ions.</p> <p>Conclusion</p> <p>The present findings suggest that HMT/HTMT activity is present in several families of higher plants including Poaceae and Brassicaceae, and is involved in the formation of methyl halides. Moreover, it was found that the emission of methyl iodide from plants was affected by the iodide concentration in the cultures. The recombinant RsHTMT demonstrated enzymatic properties similar to those of <it>Brassica oleracea </it>HTMT, especially in terms of its high specificity for iodide, bisulfide, and thiocyanate ions. A survey of biogenic emissions of methyl halides strongly suggests that the HTM/HTMT reaction is the key to understanding the biogenesis of methyl halides and methylated sulfur compounds in nature.</p

A New Secured Technique for Suprahepatic Vena Caval Anastomosis in Porcine Liver Transplantation

It is well recognized that hemorrhage or kinking of the suprahepatic vena caval anastomosis is the most fatal complication apparent within 24 hr after orthotopic liver transplantation in the pig. A secured technique for suprahepatic vena caval anastomosis is described in detail herein. Our technique include (1) the use of a diaphragmatic cuff, (2) the closure of phrenic vein orifices using transfixation technique, and (3) the application of "stay-suture" in the orifice of right phrenic vein. This technique has added significantly to the strength of the suprahepatic vena caval anastomosis, and there has been no experiences of uncontrollable bleeding and kinking of suprahepatic vena caval anastomosis in 48 porcine orthotopic transplants of the liver. In conclusion, we believe that this technique described herein is a simplified and secured method to avoid the hemorrhage and kinking of suprahepatic anastomosis in porcine liver transplantation

Improved Techniques for Orthotopic Liver Transplantation in Pigs: A preliminary study

Orthotopic liver transplantations were performed on 12 pigs between November, 1986 and February, 1987. Survivals and causes of death were assessed according to the type of surgical procedure employed. Six operations were carried out according to the original procedure of Terblanche et al, whereas for other six animals, the transplantation was conducted by our modified procedure in which cannulation was made into the splenic vein without splenectomy at the veno-venous (v-v) bypass and a diaphragmatic cuff was used for the anastomosis of suprahepatic vena cava. 1/6 animals with original procedure and 5/6 with our modified procedure survived for more than 7 days. The total ischemic time was significantly short in the group subjected to the modified procedure. The major cause of death in the group on which the original procedure was conducted was gastric ulceration, accounting for 67% of the mortality, whereas in the modified procedure group, the mortality rate was reduced significantly to 17%. This operative technique has provided excellent survival rates in our transplanted animals

Analyses of projection route of nitroxidergic nerve and its transmission mechanism

科学研究費補助金研究成果報告書研究種目: 基盤研究(B)研究期間: 1999～2001課題番号: 11470023研究代表者: 岡村 富夫（滋賀医科大学・医学部・教授）研究分担者: 安屋敷 和秀（滋賀医科大学・医学部・助教授）研究分担者: 藤岡 秀行（滋賀医科大学・医学部・助手）研究協力者: 戸田 昇（滋賀医科大学・名誉教授

Analysis of Mechanisms Underlying Vascular Nitroxidergic Innervation and its Pathogenic Implication

科学研究費補助金研究成果報告書研究種目: 基盤研究(B)研究期間: 1996～1997課題番号: 08457028研究代表者: 戸田 昇（滋賀医科大学・医学部・教授）研究分担者: 岡村 富夫（滋賀医科大学・医学部・助教授）研究分担者: 安屋敷 和秀（滋賀医科大学・医学部・助手）研究分担者: 吉田 一秀（滋賀医科大学・医学部・助手

Proteomic Identification of Protein Targets for 15-Deoxy-Δ12,14-Prostaglandin J2 in Neuronal Plasma Membrane

15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) is one of factors contributed to the neurotoxicity of amyloid β (Aβ), a causative protein of Alzheimer's disease. Type 2 receptor for prostaglandin D2 (DP2) and peroxysome-proliferator activated receptorγ (PPARγ) are identified as the membrane receptor and the nuclear receptor for 15d-PGJ2, respectively. Previously, we reported that the cytotoxicity of 15d-PGJ2 was independent of DP2 and PPARγ, and suggested that 15d-PGJ2 induced apoptosis through the novel specific binding sites of 15d-PGJ2 different from DP2 and PPARγ. To relate the cytotoxicity of 15d-PGJ2 to amyloidoses, we performed binding assay [3H]15d-PGJ2 and specified targets for 15d-PGJ2 associated with cytotoxicity. In the various cell lines, there was a close correlation between the susceptibilities to 15d-PGJ2 and fibrillar Aβ. Specific binding sites of [3H]15d-PGJ2 were detected in rat cortical neurons and human bronchial smooth muscle cells. When the binding assay was performed in subcellular fractions of neurons, the specific binding sites of [3H]15d-PGJ2 were detected in plasma membrane, nuclear and cytosol, but not in microsome. A proteomic approach was used to identify protein targets for 15d-PGJ2 in the plasma membrane. By using biotinylated 15d-PGJ2, eleven proteins were identified as biotin-positive spots and classified into three different functional proteins: glycolytic enzymes (Enolase2, pyruvate kinase M1 (PKM1) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH)), molecular chaperones (heat shock protein 8 and T-complex protein 1 subunit α), cytoskeletal proteins (Actin β, F-actin-capping protein, Tubulin β and Internexin α). GAPDH, PKM1 and Tubulin β are Aβ-interacting proteins. Thus, the present study suggested that 15d-PGJ2 plays an important role in amyloidoses not only in the central nervous system but also in the peripheral tissues

摘出兎心房膜電位に及ぼすReserpineの影響

京都大学0048新制・課程博士医学博士医博第98号新制||医||36(附属図書館)322京都大学大学院医学研究科生理系専攻(主査)教授 島本 暉朗, 教授 井上 章, 教授 山田 肇学位規則第5条第1項該当Kyoto UniversityDA