糖皮质激素及异烟肼预防食管碱性腐蚀伤后瘢痕狭窄的实验研究

实验家犬采用Ｄａｖｉｓ食管碱性腐蚀伤模型，结果显示：甲基强的松龙治疗组，狭窄段食管的管径和食管的顺应性均明显大于对照组，而胶原含量及图象分析瘢痕组织中胶原纤维的密度均显著低于对照组，表明甲基强的松龙确有控制食管腐蚀伤后瘢痕狭窄的作用。但异烟肼组所测得的上述指标，均显著优于甲基强的松龙组，说明异烟肼预防食管腐蚀伤后瘢痕狭窄的效果优于甲基强的松龙，且其不良反应小，可以长期应用。无论甲基强的松龙或异烟肼，如同时应用青霉素均可加强治疗效果。     

Identification of N2 as a metabolite of acetylhydrazine in the rat

 In the pathogenesis of isoniazid-induced hepatic injury, cytochrome P450-dependent metabolic activation of the metabolite, acetylhydrazine (AcHz), is the crucial step. Exhalation of [¹⁴C]-carbon dioxide has previously been used to quantify indirectly this pathway. In contrast, according to the current concept of AcHz bioactivation, molecular nitrogen is produced directly, but has not yet been identified. Here, we measured [¹⁵N]-nitrogen and ¹⁴CO₂ exhalation, after the administration of [¹⁵N₂]-[¹⁴C]-AcHz, in rats. Laser magnetic resonance (LMR) spectroscopy, a new sensitive and specific technique for the measurement of ¹⁵N and ¹⁴N in gas samples, was used. To demonstrate the involvement of cytochrome P450, rats were treated with phenobarbital (PB) or PB + cobalt(II) chloride (CoCl₂) (n=3 in each group). Time-dependent ¹⁵N₂ exhalation differed significantly between treatment groups (p<0.001). At 240 min, cumulative exhalation of ¹⁵N was 1.92±0.43% (mean±SE) of the dose in the control group, 2.53±0.23% in the PB group, and 1.00±0.15% in the PB+CoCl₂ group (p<0.05 compared to controls, p<0.01 compared to PB). Cumulative exhalation of ¹⁴CO₂ in 24 h ranged from 15.1 to 21.9%, with no significant difference between treatment groups. In conclusion, N₂ is a metabolite of AcHz. N₂ formation reflects the cytochrome P450-mediated activation of AcHz and can be used as an index of this pathway. Generally, LMR spectroscopy is valuable for monitoring any N₂-liberating process in vivo. Received: 14 March 1995/Accepted: 15 August 1995     

2,3-Dichloro-5,6-dicyano-1,4-benzoquinone as a redox titrant

An oxidimetric titrant, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in anhydrous acetic acid is used for the semimicro-determination of hydrazine hydrate, phenylhydrazine hydrochloride, isoniazid and iproniazid phosphate in pure forms as well as in some pharmaceutical preparations containing isoniazid and iproniazid phosphate. The end point was detected potentiometrically using a platinum-calomel combination electrode. The results obtained are compared statistically with those obtained by the official methods and they are in good agreement.     

Black-gold: a simple, high-resolution histochemical label for normal and pathological myelin in brain tissue sections

A novel haloaurophosphate complex called Black-Gold has been synthesized and applied to localize myelin within the central nervous system. The technique is tailored to studies using formalin fixed non-solvent processed tissue. The technique stains large myelinated tracts dark red-brown, while the individual myelinated axons appear black. This study demonstrates how this novel tracer can be used to localize both normal and pathological myelin. Specific myelin changes associated with exposure to diverse neurotoxicants including kainic acid, domoic acid, 3-nitropropionic acid, Fluoro-Gold and isoniazid are demonstrated and characterized. This study also demonstrates how Black-Gold can be combined with other histochemical markers including Nissl stains, retrogradely transported fluorescent tracers and fluorescent markers of neuronal degeneration. Advantages associated with the Black-Gold technique include high resolution, high contrast, short histochemical processing time, and consistent reproducibility.     

寡核苷酸表达谱揭示异烟肼耐药对结核分支杆菌致病性的影响

目的研究结核分支杆菌异烟肼耐药菌株与H37Rv异烟肼敏感菌株感染巨噬细胞后差异表达的基因. 方法利用高密度cDNA芯片检测巨噬细胞U937感染结核分支杆菌异烟肼耐药菌株与H37Rv后的基因表达谱的差异. 结果两者诱导巨噬细胞的差异表达基因有53条,异烟肼耐药菌株比敏感菌株诱导多种趋化因子和细胞免疫增强的细胞因子表达上调和免疫抑制细胞因子IL-10等表达下调. 结论异烟肼耐药对细菌毒力有明显的影响,异烟肼耐药菌株的致病力下降,异烟肼耐药菌株容易被宿主免疫系统清除;结果为耐多药结核病控制提供依据;骨桥接素和巨噬细胞趋化因子等,在抗异烟肼耐药结核分支杆菌感染免疫中的作用值得深入研究.     

Simultaneous quantification of isoniazid,rifampicin, ethambutol and pyrazinamide by liquid chromatography/tandem mass spectrometry

A remediable cause of poor treatment response in drug‐susceptible tuberculosis (TB) patients may be low plasma levels of one or more of the first‐line anti‐TB drugs. The aim of this work was to develop an accurate and precise LC‐MS/MS method for simultaneous quantification of all four first‐line anti‐TB drugs in plasma suitable for therapeutic drug monitoring (TDM). To adjust for degradation and losses during sample preparation, isotopically labeled compounds were used as internal standards. Plasma samples spiked with internal standards were extracted using protein precipitation with methanol and acetonitrile. Simultaneous separation of all four drugs was accomplished with a Chromolith Reversed‐Phase column and mobile phases consisting of water, methanol, ammonium acetate and formic acid with subsequent mass spectrometric quantification. The linear range of the calibration curve for isoniazid was 0.5–10 mg/L, for rifampicin 0.75–30 mg/L, for ethambutol 0.25–10 mg/L and for pyrazinamide 4–80 mg/L. The lower limit of quantification was 0.5 mg/L, 0.75 mg/L, 0.25 mg/L and 4.0 mg/L, respectively. Precision estimated by the coefficient of variation was <15% for all four drugs. The LC‐MS/MS method can readily be used for simultaneous quantification of first‐line anti‐TB drugs in plasma and is well suited for TDM.     

Evaluation of Which Reactive Metabolite,If Any,Is Responsible for a Specific Idiosyncratic Reaction

Reactive metabolites are believed to be responsible for most idiosyncratic drug reactions. It is often assumed that if a reactive metabolite is found, it must be responsible for the idiosyncratic reactions associated with that drug. However, the evidence linking reactive metabolites and idiosyncratic reactions is circumstantial at best, and in many cases we have virtually no evidence. Furthermore, it is common for a drug to form several reactive metabolites, so it can be difficult to determine which, if any, is responsible for a given idiosyncratic reaction. Although the reactive metabolite hypothesis is logical, it has important implications for drug development, and we need to develop ways to test the hypothesis for specific drugs rigorously. Valid animal models are a powerful tool for testing whether a specific reactive metabolite is responsible for a specific adverse reaction and for studying further the mechanism by which it may induce such reactions; however, such models are rare.     

槲皮素抑制异烟肼诱导的L-02细胞线粒体氧化应激性DNA损伤

目的:探讨活性氧(ROS)介导的线粒体氧化损伤在异烟肼(INH)诱导L-02细胞DNA损伤中的作用及槲皮素对细胞的保护作用。方法:建立体外培养INH致肝细胞L-02损伤的模型,将细胞分为对照(control)组、INH组、槲皮素低剂量(Que low)及高剂量(Que high)组。利用彗星试验评价细胞DNA损伤;制备L-02细胞线粒体,应用荧光探针DCFH-DA和rhodamine 123检测细胞线粒体ROS水平及线粒体膜电位(ΔΨm);采用TBA法测定丙二醛(MDA)含量;应用黄嘌呤氧化酶法测定超氧化物歧化酶(SOD)的活性;采用Western blotting法检测细胞中Bcl-2和Bax蛋白表达,计算Bax/Bcl-2值。结果:INH可诱导L-02细胞DNA损伤,使细胞线粒体ROS水平、细胞MDA含量及Bax/Bcl-2值明显增高,并使细胞ΔΨm值和SOD活性明显下降。而槲皮素能减轻细胞DNA损伤,减少细胞ROS水平,增加细胞ΔΨm值,降低细胞MDA含量,增加SOD活性,减少Bax/Bcl-2值。结论:INH可通过诱导细胞线粒体氧化应激导致L-02细胞DNA损伤。槲皮素能减轻INH诱导L-02细胞的DNA损伤,对L-02细胞具有保护作用,可能与其抑制ROS介导的线粒体氧化损伤有关。     

Hepatoprotective Activity of Heptoplus on Isoniazid and Rifampicin Induced Liver Damage in Rats

The present study is designed to evaluate the efficacy of heptoplus a polyherbal formulation as an oral supplementary agent for isoniazid and rifampicin induced hepatotoxicity in rats. 50 and 100 mg/kg of heptoplus supplement were fed orally to the rats along with isoniazid and rifampicin and compared to rats treated with 100 mg/kg Liv 52 standard drug. Rats treated with isoniazid and rifampicin suffered from severe oxidative stress by the virtue of free radicals induced lipid per oxidation. As a result abnormal index of serum biochemical markers for liver function and increased liver lysosomal enzymes activity was observed. However rats nourished with 100 mg/kg of heptoplus and Liv 52 protected the liver from oxidative damage by maintaining normal antioxidant profile status and restored normal serum liver biochemical markers. Increased liver lysosomal enzymes activity is prevented in the rats supplemented with heptoplus and Liv 52. Histopathological analysis also revealed severe vascular changes and lobular necrosis in the treatment of isoniazid and rifampicin. Heptoplus (100 mg/kg) and Liv 52 supplemented rats liver apparently revealed normal architecture of liver. This study confirms that heptoplus has liver protective activity against Isoniazid and Rifampicin induced liver injury in rats, in par with Liv 52.     

中国异烟肼耐药结核分枝杆菌基因突变特征分析

目的: 明确中国异烟肼(INH)耐药结核分枝杆菌基因突变的分子特征。方法: 在PubMed、中国知网、万方、维普数据库中检索有关中国结核分枝杆菌耐INH基因突变的研究文献,对纳入文献的突变基因的突变位点、突变类型,以及氨基酸改变数量等信息进行整合分析。结果: 共纳入69篇中英文文献,共6393株INH耐药结核分枝杆菌。95.71%(6119/6393)检测到基因突变或缺失,其中katG、inhA、aphC突变数量最多,分别占77.57%(4959/6393)、15.20%(972/6393)、3.69%(236/6393)。单基因单位点突变占87.80%(5613/6393),联合突变占12.20%(780/6393)。katG315突变占INH耐药菌株总数的56.22%(3594/6393),katG463突变占10.03%(641/6393),inhA15突变占10.10%(646/6393)。突变形式最常见的是C→T,占10.03%(641/6393)。结论:中国INH耐药结核分枝杆菌突变基因最多的是katG、inhA、ahpC,突变密码子最多的是katG315、katG463、inhA15。