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.     

猕猴急性脑缺血大脑细胞及线粒体内几种酶活性和cAMP的变化

给10只猕猴结扎4根动脉造成急性脑缺血15分钟及30分钟后,大脑细胞线粒体内的磷酸肌酸激酶活性增高,但缺血达60分时酶活性较15分钟的降低。线粒体内的异柠檬酸脱氢酶活性降低,缺血时间越长,降低越明显。大脑细胞浆内的乳酸脱氢酶活性开始增高以后降低。缺血15分钟后大脑皮层组织中的cAMP含量减少,30分钟后又升高。对上述改变的可能机制作了讨论。     

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。     

Effect of Dihydrotestosterone on the Rate of Ethanol Elimination in Healthy Men

Testosterone (T) and, more potently, dihydrotestosterone (DHT), are in vitro inhibitors of hepatic alcohol dehydrogenase (ADH). An increase in the rate of ethanol disappearance (RED) in man has been observed after orchidectomy. We thus investigated the influence of DHT administration on RED in 10 healthy male volunteers. RED was estimated after an oral ethanol bolus (0.6 g/kg), before and after a 14-day treatment with DHT (2 x 125 mg per day percutaneously; Andractim, Besins iscovesco, France). A mean 11.5-fold increase in DHT levels and a 2.0-fold decrease in T values were observed after DHT administration, confirming the good compliance with treatment. RED was decreased after DHT (0.168 +/- 0.043 vs. 0.137 +/- 0.043 g/l/hr; mean +/- SD; p less than 0.01 using Wilcoxon's paired comparison test). These data are consistent with a DHT-induced inhibition of hepatic ADH in vivo. This could have a beneficial effect by decreasing acetaldehyde production in alcoholic patients, in whom marked hypoandrogenism frequently occurs.     

Acetaldehyde Metabolism in Different Aldehyde Dehydrogenase-2 Genotypes

In order to clarify the relationships between acetaldehyde (Ac-CHO) metabolism and low Km (mitochondrial) aldehyde dehydrogenase (ALDH2) genotypes, hepatic ALDH2 activity was determined and serial changes of blood Ac-CHO levels after ethanol administration were analyzed in the individuals homozygous for the normal ALDH2 genes, heterozygous for the normal and mutant ALDH2 genes, and homozygous for the mutant ALDH2 genes. Genomic DNA was extracted from white blood cells and genotyping of ALDH2 was performed using the polymerase chain reaction technique and slot blot hybridization with synthesized oligonucleotide probes specific to the normal and mutant ALDH2 genes. ALDH2 activity was not detectable in the liver in two cases of the mutant homozygote. In four out of eight cases of the heterozygote, hepatic ALDH2 activity was measurable, although the activity was lower compared with that in the normal homozygote. Blood ethanol levels after alcohol administration were not different among the three different ALDH2 genotypes. Blood Ac-CHO levels after drinking of alcohol were significantly higher in the heterozygotes and the mutant homozygotes than in the normal homozygotes. The levels after a moderate amount of ethanol (0.8 g/kg of body weight) in a case of the mutant homozygote were not different from those of the heterozygotes. However, the levels after a small amount of ethanol (0.1 g/kg of body weight) were significantly higher in the mutant homozygotes than in the heterozygotes. These results indicate that hepatic ALDH2 activity is lacking completely, and metabolism of Ac-CHO in the liver is severely impaired in the homozygotes of the mutant ALDH2 genes.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Lactate dehydrogenase isoenzymes in tumours of the nervous system

Summary The variations in the isoenzymes of lactic acid dehydrogenase have been studied in a series of tumours of the nervous system. From these the ratio of heart muscle component to skeletal muscle component (the H/M ratio) has been calculated and compared with the H/M ratio of a variety of regions of normal brain. Oligodendrogliomata were found to have a very high H/M ratio. There was a decrease in the ratio with increasing degrees of de-differentiation of all tumours studied. However the H/M ratio does not appear directly related to the rate of growth irrespective of the tissue of origin of the tumour. Tumours derived from different tissues appear to have their own range of ratios. Tumour cyst fluids showed similar ratios to their parent tumours.