The effect of p,p'-DDT (dicophane) and its main metabolites on the respiration of rat liver mitochondria

The effects of DDT, DDE, DDOH and DDA on the oxidation of NADH, glutamate, -hydroxybutyrate and sucoinate by rat liver mitochondria were investigated. The influence of these compounds on the activity of purified liver glutamate dehydrogenase was also checked. It was found that DDT and all those of its metabolites investigated inhibited oxidation of NAD-linked substrates by both intact and sonicated mitochondria. The water-soluble metabolites of DDT (DDOH and DDA) stimulated succinate oxidation by intact but not by sonicated mitochondria, and inhibited the activity of glutamate dehydrogenase. It is concluded that DDT and its metabolites may affect mitochondrial respiratory chain between NADH and CoQ, inhibit glutamate dehydrogenase, and uncouple oxidative phosphorylation.     

降钙素基因相关肽对大鼠小肠缺血预适应的保护作用

目的探讨降钙素基因相关肽(CGRP)在大鼠小肠缺血预适应中的作用及意义。方法①健康Wistar雄性大鼠,体质量(280±30)g,分为3组(各8只),对照组(CON):仅分离肠系膜上动脉(SMA),不夹闭,观察90 min;缺血再灌组(I/R):分离SMA,夹闭30 min,再灌注60 min,结束实验;缺血预适应组(IP):分离SMA,夹闭SMA 5 min反复3次,然后再夹闭30 min,再灌注60 min,结束实验。②利用放射免疫法测定CGRP含量,以乳酸脱氢酶(LDH)、丙二醛(MDA)含量变化和形态学变化为指标,评价缺血再灌注损伤。结果缺血预适应可明显抑制大鼠小肠缺血再灌注损伤后LDH的水平增高,降低MDA的含量(P<0.01),保护小肠黏膜不受损伤。结论CGRP为大鼠小肠缺血再灌注损伤中关键性介质之一,缺血预适应可提高大鼠小肠缺血再灌注后CGRP的水平,对抗缺血再灌注损伤。     

15-PGDH抑制剂对人胃癌细胞生长和COX-2表达的影响

背景：15-羟基前列腺素脱氧酶（15-PGDH）是前列腺素生物降解的关键酶,对环氧合酶-2（COX-2）具有生理性拮抗作用,其表达减少和活性降低与多种恶性肿瘤的发生、发展有关。目的：观察15-PGDH选择性抑制剂Cayl0397对人胃癌细胞生长、凋亡和COX-2表达的影响,探讨15．PGDH与COX-2在胃癌中的可能关系以及15-PGDH的抗肿瘤机制。方法：以不同浓度Cay10397干预人胃癌细胞株MKN-28,MTr实验和流式细胞分析检测细胞生长和凋亡情况;RT—PCR和蛋白质印迹法检测凋亡相关基因survivin、bax、bcl—xLmRNA表达以及15-PGDH、COX-2mRNA和蛋白表达。结果：Cayl0397在浓度大于2．5μmol／L、作用时间超过48h的条件下能促进MKN-28细胞增殖（P〈0．05）,但其对MKN-28细胞凋亡无明显影响。经5—20μmol／LCayl0397作用72h的MKN-28细胞,survivin、bcl-xLmRNA表达显著升高（P〈0．05）,baxmRNA以及15-PGDHmRNA和蛋白表达显著降低（P〈0．05）,COX-2mRNA和蛋白表达无明显变化。结论：抑制15-PGDH表达可促进人胃癌细胞增殖,但对COX-2表达无明显影响。15-PGDH可能通过下调抗凋亡基因survivin、bcl-xL表达、上调促凋亡基因bax表达而诱导人胃癌细胞凋亡。     

Contribution of NADH Increases to Ethanol's Inhibition of Retinol Oxidation by Human ADH Isoforms

Background:  A decrease in retinoic acid levels due to alcohol consumption has been proposed as a contributor to such conditions as fetal alcohol spectrum diseases and ethanol-induced cancers. One molecular mechanism, competitive inhibition by ethanol of the catalytic activity of human alcohol dehydrogenase (EC 1.1.1.1) (ADH) on all-trans-retinol oxidation has been shown for the ADH7 isoform. Ethanol metabolism also causes an increase in the free reduced nicotinamide adenine dinucleotide (NADH) in cells, which might reasonably be expected to decrease the retinol oxidation rate by product inhibition of ADH isoforms.
Methods:  To understand the relative importance of these two mechanisms by which ethanol decreases the retinol oxidation in vivo we need to assess them quantitatively. We have built a model system of 4 reactions: (1) ADH oxidation of ethanol and NAD⁺, (2) ADH oxidation of retinol and NAD⁺, (3) oxidation of ethanol by a generalized Ethanol_oxidase that uses NAD⁺, (4) NADH_oxidase which carries out NADH turnover.
Results:  Using the metabolic modeling package S crum P y , we have shown that the ethanol-induced increase in NADH contributes from 0% to 90% of the inhibition by ethanol, depending on (ethanol) and ADH isoform. Furthermore, while the majority of flux control of retinaldehyde production is exerted by ADH, Ethanol_oxidase and the NADH_oxidase contribute as well.
Conclusions:  Our results show that the ethanol-induced increase in NADH makes a contribution of comparable importance to the ethanol competitive inhibition throughout the range of conditions likely to occur in vivo, and must be considered in the assessment of the in vivo mechanism of ethanol interference with fetal development and other diseases.     

一种丝状真菌活细胞生物量测定方法的研究

研究了一种基于测定脱氢酶活（DHA）的生化方法，用以测定真菌活细胞生物量和评价菌丝活力。四唑盐（TTC）在活细胞体内经脱氢酶还原生成红色甲臌（TF）。以氢化可的松生产菌株Abasidia coerulea为模式菌，通过优化染色时间（60min）、温度（45℃）、pH值8．0，提高了该方法的灵敏度。活细胞湿重与吸光度线形相关（r2=0．98），验证了该方法的有效性。另外，使用优化后的方法，所测脱氢酶比活力可以用来准确评价菌丝体活力。     

Anaerobic enzyme adaptations to sprint training in rats

Summary The adaptability of several regulatory glycolytic enzymes to chronic sprint exercise has been investigated. Ten animals were subjected to an 11-week running program consisting of 30-sec sprints interposed with 30-sec rest periods and were running up to 18 sprints a day at 80.5 m/min during the eleventh week. Ten animals served as sedentary controls. Phosphorylase (PHOS), phosphofructokinase (PFK), and pyruvate kinase (PK) activities were estimated in samples from the red and white portions of the gastrocnemius muscle (RG and WG), the red area of the vastus lateralis muscle (RV), and the soleus muscle (S). In control animals the activities of PHOS, PFK, and PK were highest in the WG, followed in order by the RV, RG, and S. Significantly more fast-twitch fibers were classified as high-oxidative in the WG of the trained animals. Only the S showed a consistent increase in glycolytic enzyme capacity with training. The findings indicate that most skeletal muscles possess sufficient anaerobic capacity to meet the demands of heavy, short-term intermittent work without adaptation to a higher level.     

The lactate dehydrogenase activity and isoenzyme pattern of normal and hypokinetic human tendons

Summary The LDH specific activity and the LDH isoenzyme pattern of eleven pairs of different normal tendons were compared with hypokinetic tendons. The LDH specific activity of hypokinetic tendons was 13–66% of the specific activity of normal tendons. The isoenzyme pattern of hypokinetic tendons altered in such a way that — with one exception — the ratio of LDH-5 and LDH-4 decreased and the ratio of LDH-1, LDH-2, and LDH-3 increased and, as a consequence, the amount of the M subunit decreased.     

与喉乳头状瘤恶变进程及预后相关分子标志物研究

目的 基于生物信息学分析筛选影响喉乳头状瘤恶变进程及预后的分子标志物。方法 从GEO和TCGA数据库分别下载成人喉乳头状瘤数据集GSE10935和喉鳞癌转录组数据,使用R语言筛选两组数据差异表达基因(DEGs)。利用韦恩图分析筛选两组共同DEGs后,使用GEPIA数据库绘制Kaplan-Meier生存曲线进行生存分析,筛选出候选基因。利用HPA数据库分析候选基因的蛋白表达情况得到关键基因后,进行单/多因素COX回归分析,及GO、KEGG功能富集分析。结果 从GSE10935数据集筛选出112个与喉乳头状瘤发生发展相关的DEGs,从喉鳞癌转录组数据筛选出1817个与喉鳞癌发生发展相关的DEGs。通过韦恩图分析得到共同DEGs 24个。GEPIA在线网站分析显示与正常组织相比,FSCN1、MMP1、IFI27在头颈鳞癌组织(HNSCC)中高表达,ALDH3A1、HLF、MMRN1低表达,差异均有统计学意义(FSCN1:P=0.002 9、MMP1:P=0.047、IFI27:P=0.035、ALDH3A1:P=0.024、HLF:P=0.008、MMRN1:P=0.036)。生存分析显示F...     

不同试剂检测血清LDH结果的可比性及偏倚评估研究

目的对测定乳酸脱氢酶(LDH)的国产与进口诊断试剂的可比性及偏倚进行评估。方法按NCCLSEP9-A文件,每天选择高、中、低值临床血清标本8例,分别用中生试剂(实验组)和罗氏试剂(对照组)进行LDH测定。每份标本正序、倒序各测定1次,连测5d,共计40例标本。记录结果并做统计学分析。结果进口罗氏和国产中生2种LDH诊断试剂对临床标本LDH的检测结果显示,方法内重复性检查DX′i≤4DX′,DY′i≤4DY′;离群点检查Eij≤4E,Eij′≤4E′;线性回归r2=0.9988;系统误差的估计值及其置信区间|B^Clow,B^Chigh|允许误差;系统误差符合临床要求。结论国产中生试剂与进口罗氏试剂测定LHD的结果之间具有良好的可比性和相关性。     

Ethnic Differences in Gastric α-Alcohol Dehydrogenase Activity and Ethanol First-Pass Metabolism

We assessed whether the low α-alcohol dehydrogenase (ADH) activity in Japanese (compared with Caucasians) affects the first-pass metabolism of ethanol. ADH isozyme activities were determined in endoscopic biopsies of the gastric corpus from 24 Japanese and 41 Caucasian men by starch gel electrophoresis and by comparing the reduction of m-nitrobenzaldehyde (a preferred substrate of α-ADH) with that of acetaldehyde (a preferred substrate of γ-ADH) and the glutathione-dependent formaldehyde oxidation (a specific reaction of χ-ADH). Alcohol pharmacokinetics was compared in 10 Japanese and 10 Caucasians after administration of ethanol (300 mg/kg of body weight) intravenously or orally, using 5 and 40% oral solutions. Japanese exhibited lower α-ADH activity than Caucasians, with no difference in the other gastric isozymes. With 5% ethanol, first-pass metabolism was strikingly lower in Japanese than in Caucasions. Blood alcohol levels were similar because of the high elimination rate in Japanese due to the hepatic β₂-ADH variant. With 40% ethanol, the first-pass metabolism increased in both groups to comparable levels, suggesting an additional contribution by χ-ADH at high ethanol concentrations. These results indicate that α-ADH activity contributes significantly to gastric ethanol oxidation and its lower activity in Japanese is associated with lesser first-pass metabolism.