蛋氨酸限制提高内源性H2S活性延缓衰老的机制研究进展

蛋氨酸限制(Methionine restriction,MetR)作为饮食限制的方法之一,能够改善多种无脊椎动物、啮齿类动物及包括人类灵长类动物的衰老及其相关疾病.但MetR对衰老的具体调节作用机制尚未完全明确,目前除了与饮食限制的共有机制以外,越来越多的研究表明内源性硫化氢(Endogenous hydrogen ...     

Objective Interpretation of the Rapid Urease Test for Helicobacter pylori Infection Using Colorimetry

BackgroundThe rapid urease test (RUT) is a major diagnostic tool for detecting Helicobacter pylori infection. This study aimed to establish an objective method for measuring the color changes in the RUT kit to improve the test’s diagnostic accuracy.MethodsA UV-visible spectrophotometer was selected as the colorimeter; experiments were conducted in three stages to objectively identify the color changes in the RUT kit.ResultsFirst, the urea broth solution showed an identifiable color change from yellow to red as the pH increased by 0.2. The largest transmittance difference detected using the UV-visible spectrophotometer was observed at a 590-nm wavelength. Second, the commercialized RUT kit also showed a gradual color change according to the pH change detected using the UV-visible spectrophotometer. Third, 13 cases of negative RUT results with a biopsy specimen and 16 of positive RUT results were collected. The transmittance detected using the UV-visible spectrophotometer showed a clear division between the positive and negative RUT groups; the largest difference was observed at a 559-nm wavelength. The lowest transmittance in the negative RUT group was 64, while the highest in the positive RUT group was 56, at the 559-nm wavelength. The UV-visible spectrophotometry reading showed a consistency of 92.7% compared with that of manual reading.ConclusionA transmittance of 60 at a 559-nm wavelength detected using UV-visible spectrophotometer can be used as a cutoff value for interpreting RUT results; this will help develop an automatic RUT kit reader with a high accuracy.     

Hydrogen Peroxide Reduces Lead-Induced Oxidative Stress to Mouse Brain and Liver

Lead (Pb) intoxication may initiate many disorders in human and animals. This study investigates the role of exogenous hydrogen peroxide (H₂O₂) in inducing mouse tolerance to Pb exposure. Results showed that the simultaneous application of 1.2 μg H₂O₂ per kg body weight efficiently protected mice against the Pb-caused injury, as revealed by decreased growth suppression caused by the Pb stress, increased antioxidative enzyme activity, reduced lipid peroxidation, and the protective effect on the nuclear DNA integrity. To our knowledge, this is the first finding of this sort. R. G. Li and T. T. Li contributed equally to this work.     

污染食品中氰化物的快速检测方法

目的:检测试剂和手持式光电比色仪联用的方法,实现对污染食品中氰化物的现场快速定量检测。方法:通过氰化物在碱性条件下,CN-可催化茚三酮自身氧化还原反应,迅速生成红棕色产物(485 nm),其呈色深浅与氰化物含量成一定相关性,于手持式光电比色仪实现定量测定。结果:氰化物浓度在0.0~0.5 mg/L范围内线性关系良好(r=0.9957);方法的检出限为0.05 mg/kg、加标回收率为84%~106%。并与国家标准方法检测结果一致。结论:试剂-光电比色仪方法用于氰化物的现场定量检测具有简便、快速、携带方便等特点,值得推广应用。     

高血流肺动脉高压大鼠钙敏感受体、硫化氢及活性氧的研究

目的：探讨肺动脉钙敏感受体（CaSR）、血浆硫化氢（H2S）、肺动脉内皮细胞中活性氧（ROS）水平在肺动脉高压发生发展中的作用。方法18只SD雄性大鼠按随机数字表法分为对照组和实验组,每组9只。实验组行左肺叶切除术,对照组行假手术,术后均喂养35 d。比较两组大鼠肺动脉压力（ mPAP ）、右心室肥厚指数、血浆H2 S、肺动脉内皮细胞ROS水平和肺动脉CaSR mRNA的表达水平。结果实验组大鼠mPAP、肺动脉内皮细胞ROS水平及右心室肥厚指数、肺动脉CaSR mRNA表达均明显高于对照组（ P＜0．05）,血浆H2 S含量明显低于对照组（ P＜0．05）。结论肺高血流肺动脉高压大鼠肺动脉CaSR mRNA表达的改变和内皮细胞ROS对细胞的损伤可能通过改变内源性H2 S的产生而共同参与肺动脉高压的形成。     

Gel Agglutination Test: Its Application to Infertile Men

In a study involving 253 men attending the Male Fertility Clinic in Nottingham, the Gelatin Agglutination Test on serum gave a positive response in 14.2% of patients and a positive response at a dilution of 1/32 in 11.5% of patients. No correlation was found between a positive GAT response and increasing age or the major pathological entities causing infertility in the male. Of the positive GAT responses, 17% reverted to negative on second testing. The value and the diagnostic importance of this test as well as its reliability is questioned.     

燃烧加热污染空气对超燃冲压发动机性能影响研究

针对燃烧加热地面试验设备存在的工质污染问题,采用数值模拟方法研究了燃烧加热污染空气对氢燃料超燃冲压发动机性能的影响。以飞行马赫数Ma=6.5,当量油气比ER=0.6为计算基准状态,分别对纯净空气和污染空气来流下氢燃料超燃冲压发动机的整机流场和性能进行了对比计算分析。燃烧化学反应模拟采用了改进的H₂/O₂七组分八方程模型,湍流模型为标准的 k-ε模型,并采用直连式燃烧室试验数据进行了数值方法的验证。研究结果表明:(1)相对于纯净空气来流,污染空气来流下的超燃冲压发动机推力和比冲均有所下降。(2)采用酒精燃烧加热器的前提下,来流参数匹配静温、静压、马赫数时,发动机性能与纯净空气来流下的结果最为接近,而匹配总温、总压、马赫数时相差最大。(3)来流参数匹配总焓、静压、马赫数的前提下,采用氢燃烧加热器时发动机性能与纯净空气来流下的结果最为接近,而采用甲烷燃烧加热器时相差最大。      

Disease susceptibility genes for autism

Autism is a complex neurodevelopmental disorder characterized by impairment in social interaction accompanied by a delay or lack of language, restricted interests, stereotyped behavior, and repetitive movement. Genetic predisposition to autism is evident from family and twin studies, and heritability in idiopathic autism is estimated at over 90%. Frequency of the disorder is approximately 1:2000 with a male to female ratio of 4:1. Affected individuals look normal at birth, and the symptoms manifest at the first 2-3 years of life. The spectrum of clinical symptoms and the severity of the disorder are variable even among siblings. Family studies and several genome-wide linkage analyses support the hypothesis of complex inheritance with involvement of as many as 10-100 genes of moderate effect. Identification of genes responsible for the phenotype would help to understand the molecular mechanisms of the disorder. Several genes have been proposed to play a role in susceptibility to autism, and this paper will overview those genes and their potential role in the disorder.     

Qualities of a French version of the Wolf Motor Function Test: A multicenter study

IntroductionThere are currently a small number of standardized tools in French that measure and compare the effect of constraint-induced movement therapy, or other recent therapies promoting motor recoveryObjectiveTo create a French version of the Wolf Motor Function Test (WMFT) and assess its reliability, minimal detectable change, and criterion validity.MethodProspective multicenter repeated-measure design with 44 patients with post stroke hemiparesis. A French Version of the WMFT was created; it was then assessed against the Fugl Meyer Assessment-Upper Extremity (French version) to establish its reliability, the minimal detectable change and its validity.ResultsInter-rater reliability was very good. Reproducibility of the scores was good. Cronbach α coefficients showed adequate internal consistency. The minimal detectable change (MDC_95%) for functional ability scores was below 10% of the highest possible score; the MDC_95% for performance time was very high at more than 90 seconds. Criterion validity was good.ConclusionThe French version of the WMFT is reliable and valid. The test shows promise for use as an objective outcome measure for people post stroke in French speaking countries.