PON1Q192R基因多态性与冠心病患者使用氯吡格雷疗效的关系

目的：探讨不同民族PON1Q192R等位基因变异频率以及PON1Q192R基因多态性与冠心病患者氯吡格雷抵抗（CR）的关联性。方法：纳入新疆医科大学第二附属医院2020年1月至2020年12月使用氯吡格雷且诊断为冠心病的患者127例,患者每日服用氯吡格雷75 mg,5 d后用血栓弹力图测定相关参数,并进行CYP2C19*2、CYP2C19*3、CYP2C19*17和PON1Q192R基因分型检测。结果：不同民族之间PON1Q192R基因突变频率差异具有统计学意义（P <0.05）,患者的血栓弹力图参数结果显示,PON1Q192R基突变并不会显著降低氯吡格雷疗效。结论：PON1Q192R基因突变频率与冠心病患者氯吡格雷反应的相关性还需要进一步研究。     

Differences in Caffeine 3-Demethylation Activity among Inbred Mouse Strains: A Comparison of Hepatic Cyp 1a2 Gene Expression between Two Inbred Strains

The 3-demethylation of caffeine can be used as an index of cytochromeP450 CYP1A2 activity in vivo. We compared the plasma levelsof caffeine and the 3-demethylated metabolite, 1,7-dimethylxanthine,in six common inbred strains (A/J, P/J, BALB/cJ, C3H/HeJ, AKR/J,and SWR/J) and one inbred strain (APN) derived in our laboratoryfrom outbred Swiss-Webster mice on the basis of its relativesusceptibility to acetaminophen-induced hepatotoxicity. We foundsignificant variations between a number of the common strains,all of which produced significantly higher caffeine 3-demethylationindices than our APN strain. In three of the six common strains,there was a significant difference between males and females,with the females having consistently lower 1,7-xanthine/caffeineratios. Hepatic Cyp1a2 expression was compared between APN andC3H/HeJ males. Microsomal methoxyresorufin O-demethylation,acetanilide 4-hydroxylation, and CYP1A2 immunoreactive proteinlevels were significantly higher in C3H/HeJ relative to APNmice, as were hepatic CYP1A2 mRNA levels. These results indicatethe importance of strain and gender to the outcome of pharmacologicalor toxicological studies involving CYP1A2-mediated metabolism,as well as the suitability of the plasma 1,7-dimethylxanthine/caffeineratio as a marker of CYP1A2 activity in the mouse. The strikingdifferences observed between the APN and C3H/HeJ mice suggestthat these strains may be suitable for a genetic analysis ofthe regulation of the basal expression of CYP1A2, a key enzymeIn procarcinogen activation.     

Effect of 5-(p-hydroxyphenyl)-5-phenylhydantoin (p-HPPH) enantiomers,major metabolites of phenytoin,on the occurrence of chronic-gingival hyperplasia: in vivo and in vitro study

The purpose of this study was to assess the possible role of the (R)- and (S)- enantiomers of the phenytoin metabolite p-HPPH in the pathogenesis of gingival hyperplasia (GH). About 98% of circulating p-HPPH is in the (S)-form. There were significant differences between patients with and without GH in (R)-p-HPPH level (0.055 vs 0.042 g·ml^–1), both enantiomer/racemate level ratios, and R/S enantiomeric ratio (0.0313 vs 0.0232); an increase in serum (R)-p-HPPH level was observed in patients with GH. In separate experiments, the effect of p-HPPH enantiomers on the proliferation of the normal human dermal fibroblast was studied. The in vitro study showed that (R)-p-HPPH selectively stimulated fibroblast growth. The results suggest that the least abundant metabolite, (R)-p-HPPH, is the most toxic with respect to gingival hyperplasia.     

地西泮在两组基因型之间的代谢差异

为研究地西泮在两组基因型（ｗｔ／ｍｌ和ｍｌ／ｍｌ）的国人体内代谢的差异,采用ＰＣＲ法筛选１２位符合基因型要求的受试 ,６位为ＣＹＰ２Ｃ１９突变型纯合子（ｍｌ／ｍｌ）,６位为ＣＹＰ２Ｃ１９的杂合子（ｗｔ／ｍｌ）。每位受试者口服５ｍｇ地西泮片,然后用气相色谱法测定其血浆中地西泮的浓度,计算其药代动力学参数,结果显示两组受试者之间地西泮代谢有显著性差异。结论：遗传因素是决定地西泮代谢的重要因素。     

Metabolism of risperidone to 9-hydroxyrisperidone by human cytochromes P450 2D6 and 3A4

Risperidone is a relatively new antipsychotic drug that has been reported to improve both the positive and the negative symptoms of schizophrenia and produces relatively few extrapyramidal side effects at low doses. Formation of 9-hydroxyrisperidone, an active metabolite, is the most important metabolic pathway of risperidone in human. In the present study, in vitro metabolism of risperidone (100 μM) was investigated using the recombinant human cytochrome P450 (CYP) enzymes CYP1A1, CYP1A2, CYP2C8, CYP2C9-arg₁₄₄, CYP2C9-cys₁₄₄, CYP2C19, CYP2D6, CYP3A4 and CYP3A5 supplemented with an NADPH-generating system. 9-Hydroxyrisperidone was determined by a new HPLC method with an Hypersil CN column and a UV detector. Of these enzymes, CYPs 2D6, 3A4 and 3A5 were found to be the ones capable of metabolising risperidone to 9-hydroxyrisperidone, with activities of 7.5, 0.4 and 0.2 pmol pmol^–1 CYP min^–1, respectively. A correlation study using a panel of human liver microsomes showed that the formation of 9-hydroxyrisperidone is highly correlated with CYP2D6 and 3A activities. Thus, both CYP2D6 and 3A4 are involved in the 9-hydroxylation of risperidone at the concentration of risperidone used in this study. This observation is confirmed by the findings that both quinidine (inhibitor of CYP2D6) and ketoconazole (inhibitor of CYP3A4) can inhibit the formation of 9-hydroxyrisperidone. Furthermore, inducers of CYP can significantly increase the formation of 9-hydroxyrisperidone in rat. The formation of 9-hydroxyrisperidone is highly correlated with testosterone 6β-hydroxylase activities, suggesting that inducible CYP3A contributes significantly to the metabolism of risperidone in rat. Received: 4 May 1998 / Accepted: 26 October 1998     

Xanthine oxidase inhibition by allopurinol affects the reliability of urinary caffeine metabolic ratios as markers for N-acetyltransferase 2 and CYP1A2 activities

Objectives: To evaluate the in vivo effect of xanthine oxidase (XO) inhibition by allopurinol on the determination of polymorphic N-acetyltransferase 2 (NAT2) and cytochrome P450 1A2 (CYP1A2) with urinary caffeine metabolic ratios. Methods: In an open, prospective study involving 21 healthy subjects (eight fast, 13 slow NAT2 acetylators) allopurinol (300 mg perday) was administered orally on trial days 1–8, followed by a wash-out period of 8 days. Urinary caffeine tests (200 mg caffeine p.o.) were performed repetitively. Urine was collected for 8 h and venous blood samples for the determination of allopurinol, oxypurinol and uric acid were drawn. The urinary caffeine metabolites 1-methyluric acid (1MU), 1-methylxanthine (1MX), 1,7-dimethyluric acid (17MU), 1,7-dimethylxanthine (17MX), 5-acetylamino-6-formylamino-3-methyluracil (AFMU), plasma allopurinol and oxypurinol were analysed using high-performance liquid chromatography (HPLC). Results: During XO inhibition by allopurinol, the formation of 1MU from 1MX and therefore the XO ratio 1MU/1MX decreased to 15.9 (1.2)% [mean with (SEM)] of baseline values (P < 0.005). The NAT2 ratio AFMU/1MX decreased likewise to 56.7 (6.3)% (P < 0.005). AFMU/(AFMU + 1MX + 1MU), an alternative NAT2 ratio, remained constant, but the CYP1A2 ratio (AFMU + 1MX + 1MU)/17MU, used to express CYP1A2 activity, transiently increased to 167 (13)% (P < 0.005). The NAT2 phenotype did not influence CYP1A2 and XO ratios or plasma oxypurinol pharmacokinetics. Conclusions: Several caffeine metabolic ratios are commonly used to express the activities of NAT2, CYP1A2 and XO both in healthy volunteers and in polymedicated patients, although their reliability has not been evaluated thoroughly during concurrent drug administration. The findings of this study suggest that NAT2 phenotyping should be performed using the ratio AFMU/(AFMU + 1MX + 1MU) if an XO inhibitor may be present. It also shows that the determination of CYP1A2 activity with caffeine as a metabolic probe is considerably altered under these conditions. Thus, concomitant drug administration may impair the robustness of multiple pathways of the complex caffeine test. This points to the need for alternative probes, designed to assess only the activity of a single enzyme because, in contrast to healthy volunteers, in patients known or unknown drug interactions may often be present. Received: 10 August 1998 / Accepted in revised form: 5 October 1998     

Family studies of the steroid 21-hydroxylase and coplement C4 genes define 11 haplotypes in classical congenital adrenal hyperplasia in The Netherlands

Two steroid 21-hydroxylase genes are normally present within the human major histocompatibility complex near the genes encoding the fourth component of complement (C4A and C4B). Steroid 21-hydroxylase is encoded by the CYP21 gene, while the highly homologous CYP21P gene is a pseudogene. We studied steroid 21-hydroxylase and complement C4 haplotypes in 33 Dutch patients (29 families) suffering form classical congenital adrenal hyperplasia (CAH) and in their 80 family members, and also in 55 unrelated healthy controls, using 21-hydroxylase and complement C4 cDNA probes. Eleven different haplotypes, defined in terms of gene deletions, gene duplications, conversions of CYP21 to CYP21P, and long and short C4 genes, were found. In 23% of the patients' haplotypes, the CYP21 gene was deleted; in 12%, it was converted into a CYP21P pseudogene. In the remaining 65%, the defect was apparently caused by a mutation not detectable by this method. The most common haplotype (with one CYP21 and one CYP21P gene) was significantly more often observed in patients with simple virilizing CAH than in those with salt-losing CAH. Comparison of the 21-hydroxylase haplotypes found in CAH patients from several countries shows evidence for considerable genetic variation between the groups studied.     

Type 1 diabetic mice are protected from acetaminophen hepatotoxicity.

Streptozotocin (STZ)-induced diabetic (DB) mice challenged with single ordinarily lethal doses of acetaminophen (APAP), carbon tetrachloride (CCl4), or bromobenzene (BB) were resistant to all three hepatotoxicants. Mechanisms of protection against APAP hepatotoxicity were investigated. Plasma alanine aminotransferase, aspartate aminotransferase, and liver histopathology revealed significantly lower hepatic injury in DB mice after APAP administration. HPLC analysis of plasma and urine revealed lower plasma t1/2, increased volume of distribution (Vd), and increased plasma clearance (CLp) of APAP in the DB mice and no difference in APAP-glucuronide, a major metabolite in mice. Interestingly, covalent binding of 14C-labeled APAP to liver target proteins; arylation of APAP to 58, 56, and 44 kDa acetaminophen binding proteins (ABPs); and glutathione (GSH) depletion in the liver did not differ between nondiabetic (non-DB) and DB mice in spite of downregulated hepatic microsomal CYP2E1 and 1A2 proteins in the DB mice, known to be involved in bioactivation of APAP. Compensatory cell division measured via 3H-thymidine pulse labeling and immunohistochemical staining for proliferating cell nuclear antigen (PCNA) indicated earlier onset of S-phase in the DB mice after exposure to APAP. Antimitotic intervention of liver cell division by colchicine (CLC) after administration of APAP led to significantly higher mortality in the DB mice suggesting a pivotal role of liver cell division and tissue repair in the protection afforded by diabetes. In conclusion, the resistance of DB mice against hepatotoxic and lethal effects of APAP appears to be mediated by a combination of enhanced APAP clearance and robust compensatory tissue repair.     

细胞色素P450 2E1(CYP2E1)的遗传多态性与非吸烟女性肺癌的危险度

我们在上海和哈尔滨二地分别收集了非吸烟女性肺癌病例各１００例和８２例以及非吸烟的女性健康人对照各９５例和８９例。分析了白细胞ＤＮＡ的细胞色素Ｐ４５０２Ｅ１基因第六内含子ＤｒａＩ切点和５’端调控区ＲｓａＩ切点的遗传多态性。虽然上海病例组ＤｒａＩ和ＲｓａＩ突变型纯合子与对照组比ＯＲ值分别为２５６和５４７，但未达显著性；哈尔滨病例组ＯＲ值分别为０４９和０４７，也无显著差异。