【目的】我々は先に大麻幻覚成分（tetrahydrocannabinol，THC）を7-hydroxy-THC（7-OH-THC）を経て活性代謝物7-oxo-THCへと酸化するサル肝ミクロソーム（Ms）酵素、即ちMicrosomal Alcohol Oxygenase()の本体としてCYP3A8を同定し、そのNADH依存性を明らかにした。本研究では、ヒトCYP3A4においてエフェクターとして作用することが知られているテストステロンやその他のステロイドの活性に与える影響を検討し、CYP3A8の触媒機能を明らかにすることを目的とした。
【方法】酵素源としてCYP3A8を発現しているニホンザル肝Msを、また補酵素はNADH及びNADPHをそれぞれ用いた。ニホンザル肝Msを用いた反応系において、両補酵素に依存した7β-OH-Δ⁸-THCを基質とする活性に対する種々のステロイド(テストステロン、β-エストラジオール、エストロン、アンドロステンジオン、プロゲステロン、コルチゾール)及びα-ナフトフラボンの影響を検討した。
【結果・考察】NADHよりもNADPH依存的活性においてステロイドによる活性の上昇が認められた。その上昇率はコントロールと比較して100μMのプロゲステロン、テストステロンの添加によりそれぞれ4倍、5倍であり、その他の検討したステロイドでは最大2倍程度であった。最も活性の上昇が認められたテストステロンの活性化機構について速度論的解析を行い考察を加える。

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The formation of 7-oxo-Δ⁸-tetrahydrocannabinol (7-oxo-Δ⁸-THC) from 7β-hydroxy-Δ⁸-THC was found in hepatic microsomes of rats. The activity was stereoselective and about 3-fold higher than that from 7α-hydroxy-Δ⁸-THC. The oxidative activity of 7α- and 7β-hydroxy-Δ⁸-THC to 7-oxo-Δ⁸-THC was significantly higher in male than in female, and significantly enhanced by both dexamethasone and phenobarbital, and then inhibited up to about 20% of the control value by antibody against P450GPF-B, presumably a member of the 3A subfamily, a major enzyme responsible for the formation of 7-oxo-Δ⁸-THC in guinea pigs. This antibody also inhibited the formation of 7α- and 7β-hydroxy-Δ⁸-THC, and 7-oxo-Δ⁸-THC from Δ⁸-THC by hepatic microsomes of rats. These results indicate that there is a sex-related difference in the oxidatio of 7-hydroxy-Δ⁸-THC to 7-oxo-Δ⁸-THC and the reaction is mainly catalyzed by P450 enzyme(s) beloging to the 3A subfamily as major enzyme(s) of microsomal alcohol oxygenase in rats.

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A cytochrome P450 isozyme (designated P450GPF-B) that catalyzes the oxidation of 7α-OH and 7β-OH-Δ⁸-THCs to 7-oxo-Δ⁸-THC has been purified from liver microsomes of untreated female guinea pigs. P450GPF-B had an apparent MW of 50kD, and specific content of 18.7 nmol/mg protein. Analysis of the N-terminal amino acid sequence suggests that the isozyme is a member of the P450 3A gene subfamily. Antibody against P450GPF-B significantly inhibited the microsomal formation of 7-oxo-Δ⁸-THC from 7β-OH-Δ⁸-THC, but not 7α-OH-Δ⁸-THC. The oxidation of 7α-OH and 7β-OH-Δ⁸-THCs to 7-oxo-Δ⁸THC in liver microsomes of male rats was significantly higher than that of female rats. The catalytic activity in rat was significantly induced by treatment of dexamethasone and phenobarbital, and was significantly inhibited by antibody against P450GPF-B. These results suggest that P450GPF-B is a major isozyme responsible for the formation of 7-oxo-Δ⁸-THC from 7β-OH-Δ⁸-THC in guinea pig liver microsomes and that the formation of 7-oxo-Δ⁸-THC in rat is also catalyzed by P450 isozyme(s) immunologically related to P450GPF-B.

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7α- and 7β-OH-Δ⁸-THC activities in mouse liver were significantly enhanced by dexamethasone and phenobarbital. A cytochrome P450, named P450MDX-B, was purified from hepatic microsomes of dexamethasone-pretreated mice. Anti-P45OMDX-B antibody inhibited 7-OH-Δ⁸-THC activity in mouse liver. A cDNA clone encoding a P450 isozyme was isolated from a C57BL/6 mouse liver cDNA library. The nucleotide sequence of coding region of this cDNA was identical with that of the known mouse Cyp3al 1 and the deduced amino acid sequence had an N-terminal sequence identical to that of P45OMDX-B. Expression plasmid of Cyp3al1 was transformed into exponentially growing COS-7 cells by the method of electroporation. Immunologically related protein with P45OMDX-B which had the same molecular mass was expressed in the COS cells microsomes (COS-3a11). The COS-3a11 catalyzed the oxidation of 7-OH-Δ⁸-THC to 7-oxo-Δ⁸-THC. Oxygen-18 (¹⁸O) derived from atmospheric oxygen was incorporated into 7-oxo-Δ⁸-THC from 7α-OH-Δ⁸-THC by hepatic microsomes, P45OMDX-B and COS3a11. On the other hand, incorporation of the stable isotope into the oxidized metabolite from 7β-OH-Δ⁸-THC was negligible. However, when 7β-OH-Δ⁸-THC was incubated with mouse hepatic microsomes using cumene hydroperoxide instead of NADPH under ¹⁸O₂, ¹⁸O was not incorporated into 7-oxo-Δ⁸-THC.
These results suggested that 7α-OH-Δ⁸-THC may be oxidized to the corresponding ketone by Cyp3all via a gemdiol pathway. On the other hand, 7β-OH-Δ⁸-THC may be converted to the ketone through a stereo selective dehydration of an enzyme-bound gem-diol rather than through a direct hydrogen extraction as a peroxy form of the enzyme.

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The formation of 7-oxo-Δ⁸-tetrahydrocannabinol (7-Oxo-Δ⁸-THC) from 7α- or 7β-hydroxy-Δ⁸-THC (7α- or 7β-OH-Δ⁸-THC) was found in hepatic microsomes of monkeys. The activity in 7β-OH-Δ⁸-THC was stereoselectively 2.5- to 4.6-fold higher than that from 7α-OH-Δ⁸-THC. The oxidative activities of 7α- and 7β-OH-Δ⁸-THC to 7-Oxo-Δ⁸-THC were inhibited to 35% and 10%, respectively, of the control value by the antibody against P450GPF-B (CYP3A), a major enzyme responsible for the formation of 7-Oxo-Δ⁸-THC in guinea pigs. In the Lineweaver-Burk double-reciprocal plot analysis, testosterone 6β-hydroxylase activity was competitively inhibited by 7β-OH-Δ⁸-THC. Two cytochrome P450 enzymes, called P450JM-D and P450JM-E, were purified from hepatic microsomes of Japanese monkeys. P450JM-E, assumed to be CYP3A8, immunologically reacted with the antibody against P450GPF-B and showed high forming activity of 7-Oxo-Δ⁸-THC from 7-OH-Δ⁸-THC. On the other hand, 7-Oxo-Δ⁸-THC forming activity of P450JM-D, assumed to be CYP2C, was less than 10% of that of P450JM-E (CYP3A8). Oxygen-18 (¹⁸O) derived from atmospheric oxygen was incorporated into about 40% of the corresponding ketone formed from 7α-OH-Δ⁸-THC or 8β-OH-Δ⁹-THC by P450JM-E (CYP3A8), although the incorporation of the stable isotope into the oxidized metabolite from 7β-OH-Δ⁸-THC or 8α-OH-Δ⁹-THC was negligible. These results indicate that P450JM-E (CYP3A8) is a major enzyme of the oxidation of 7-OH-Δ⁸-THC in monkey hepatic microsomes. The oxidation mechanism may proceed as follows: the α- and β-epimers of 7-OH-Δ⁸-THC or 8-OH-Δ⁹-THC may be converted to ketone through dehydration of an enzyme-bound gem-diol by P450JM-E (CYP3A8), although this stereoselective dehydration differentiates between two epimers.

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The NADH-dependent activity by hepatic microsomes of Japanese monkeys for 7-oxo-Δ⁸-tetrahydrocannabinol (7-oxo-Δ⁸-THC) formation from 7β-hydroxy-Δ⁸-THC exhibited about 70% of the NADPH-dependent activity (100%) at the substrate concentration of 72.7 μM, although NADPH was an obligatory cofactor for maximal activity. Both NADH- and NADPH-dependent activities were significantly inhibited by the typical P450 inhibitors, such as SKF525-A and metyrapone. Both activities were almost completely inhibited by the NADPH-P450 reductase inhibitor diphenyliodonium chloride. The ratio of NADH- and NADPH-dependent activities varied significantly according to the substrate concentration. Interestingly, the NADH-dependent activity was higher than that of NADPH at low substrate concentrations of 13—50 μM. The ratio was also affected by the cofactor concentration. In the reconstituted system of CYP3A8 purified from hepatic microsomes of Japanese monkeys as a major enzyme responsible for the NADPH-dependent oxidation, NADH as well as NADPH could sustain the oxidation of 7β-hydroxy-Δ⁸-THC to the corresponding ketone. The NADH-dependent oxidation of 7β-hydroxy-Δ⁸-THC by monkey livers is mainly catalyzed by CYP3A8 as well as the NADPH-dependent oxidation. These results indicate that NADH as a cofactor may be also useful for the oxidation of 7β-hydroxy-Δ⁸-THC, and that the cofactor requirement for the reaction is varied by the concentrations of substrate and/or cofactor.

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Parasitic plants have a very close association with their host. The physiological interactions between parasite and host and the signals required for parasite development are only beginning to be understood. Because of its small genome and rapid life cycle, Lotus has become a model legume. We have demonstrated that Lotus is susceptible to Orobanche crenata, a devastating pathogen of dicotyledonous crops. Lotus roots produce germination stimulant, allow haustorium formation, and support attached O. crenata plants, which develop normally to the point of flowering. Lotus was not however susceptible to other parasitic plant species examined, including O. aegyptiaca, O. minor, Striga gesnerioides and S. hermonthica. The finding that Lotus is highly susceptible to O. crenata provides an excellent opportunity to study different aspects of plant-parasite interactions, including host-parasite communication and host resistance mechanisms.

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米国では,"TQMは死んだ"というような新聞の見出しをよく目にする.しかしながら間違ってはいけない.TQMの概念や手法を用いている企業はどんどん増えている.ただ多くの企業はTQMというラベル,用語を使わないだけの話である.米国自動車産業の競争力回復に代表されるように,TQMは米国産業に目覚しいインパクトを与えた.マルコム・ボルトリッジ国家品質賞を獲得した企業の株価は,絶えずそれ以外の企業に比べて高い傾向を示している.このような成果にもかかわらず,なぜTQMは米国の経営者にある種のアピール力を失ったのであろうか.その一番の理由として,TQMの本質的な知識や全員参加という点について十分高いレベルに達している企業がほとんどないということがあげられる.その他の要因として・米国の経営者が短期的な結果を求める傾向があること・M&A(吸収・合併),買収が経営者や従業員の関心をそちらに逸らす・欧州に売るためのISO9000を取得する企業が増大・リエンジニアリングと他の新しい経営フレームワークの台頭(たとえば,従業員のエンパワーメントやラーニング・オーガナイゼーション等)があげられる.加えて米国人の新し物好きの性向という立場からは,TQMは必然的に古い経営理論ということになってしまう.このような問題点にもかかわらず,TQMという名前の是非は別として,その理念と方法は米国にとってこれからも生き残りかつ重要である.短期的な成果を上げかつ将来へ向けての体質強化というジレンマの中で,その両者を達成する上でTQMはこれからも米国ビジネスに不可欠である.

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We report a 57-yr-old woman with severe cardiac failure secondary to postnephrectomy arteriovenous fistula which was successfully removed. A review of the literature shows the rarity of this complication ; only 72 cases have been reported in the world literature including 6 cases (including the present case) from Japan. Surgical intervention is generally the treatment of choice from a fistula and provides satisfactory results for cardiac failure which is the major complication of this fistula. A characteristic bruit was observed in all reported cases. Therefore, nonsurgical closure by percutaneous embolization for a small sized shunt may be possible if early diagnosis is obtained by careful auscultation of the loin.
(Internal Medicine 31 : 98-101, 1992)

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A novel high-dissolved CO₂ device was developed for the disinfection of treated sewage wastewater. Several experiments were conducted regarding the waterborne pathogen inactivation rate, the treatment time and the disinfection target (several treated sewage wastewaters, canal and river water). The results indicated that different disinfection targets can lead to 2.8-3.0 log-inactivation of waterborne pathogens within 20 minutes of treatment under 0.3 MPa of pressure in the device. Results also showed that the suspended solid (SS) in raw water affected the disinfection efficiency.

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A new method of measuring blood pressure has been proposed, which is based on the relationship between blood pressure and pulse wave velocity that passes artery wall. We paid attention to this method as this one was very advantageous to miniaturize the blood measuring instrument. We have developed a circuit to measure pulse wave velocity which can be transduced into blood pressure value. Furthemore we have brought Casio brand blood pressuer monitor watch to the market, of which circuit is miniaturized into one chip LSI. The constitution and the blood monitoring operation of this watch are described in this Paper.

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