食管癌相关基因甲基化研究进展

人类肿瘤的发生是一个多步骤、多阶段、多基因改变与表基因改变的复杂过程,主要涉及癌基因激活和抑癌基因失活,最后引起基因表达异常.近年来研究表明,基因表达改变主要通过两大机制:一是遗传学机制(genetic mechanism),即由DNA核苷酸序列改变引起,包括突变、缺失、染色体重排等,产生结构异常的基因产物;再就是表观遗传学机制(epigenetic mechanism),即没有DNA序列变化、可遗传的基因表达(活性)的改变,DNA甲基化是其主要形式.近年来,DNA甲基化成为肿瘤研究领域一大热点,其可调控细胞增殖、凋亡、分化,且其水平与肿瘤的生物学特性密切相关.     

特异性DNA甲基化标记在肿瘤早期预警中的应用研究进展

[摘 要]DNA甲基化已成近年表观遗传学研究的热点之一。越来越多的研究表明，肿瘤发生发展过程中存在特征性的DNA甲基化紊乱，表现为基因组整体甲基化水平的降低和局部DNA区域（如抑癌基因启动子区）甲基化水平的异常升高，从而导致染色体不稳定、可移动因子激活、原癌基因异常表达和抑癌基因的失活等。目前认为，DNA的异常甲基化(低甲基化与超甲基化)在体细胞癌变进程中扮演着极其重要的角色，肿瘤特异性DNA甲基化标记是一种很有希望的肿瘤早期预警与临床前诊断标记物。     

DNA异常甲基化与肿瘤发生及早期监测

DNA甲基化已成近年表遗传学研究的热点之一.越来越多的研究表明,肿瘤发生发展过程中存在特征性的DNA甲基化紊乱,表现为基因组整体甲基化水平的降低和局部DNA区域(如抑癌基因启动子区)甲基化水平的异常升高,从而导致染色体不稳定、可移动因子激活、原癌基因异常表达和抑癌基因的失活等.目前认为,DNA的异常甲基化(低甲基化与超甲基化)在体细胞癌变进程中扮演着极其重要的角色,肿瘤特异性DNA甲基化标记是一种很有希望的肿瘤早期预警与临床前诊断标记物.     

DNA异常甲基化与肿瘤发生及早期监测

DNA甲基化已成近年表遗传学研究的热点之一.越来越多的研究表明,肿瘤发生发展过程中存在特征性的DNA甲基化紊乱,表现为基因组整体甲基化水平的降低和局部DNA区域(如抑癌基因启动子区)甲基化水平的异常升高,从而导致染色体不稳定、可移动因子激活、原癌基因异常表达和抑癌基因的失活等.目前认为,DNA的异常甲基化(低甲基化与超甲基化)在体细胞癌变进程中扮演着极其重要的角色,肿瘤特异性DNA甲基化标记是一种很有希望的肿瘤早期预警与临床前诊断标记物.     

DNA异常甲基化与肿瘤发生及早期监测

DNA甲基化已成近年表遗传学研究的热点之一.越来越多的研究表明,肿瘤发生发展过程中存在特征性的DNA甲基化紊乱,表现为基因组整体甲基化水平的降低和局部DNA区域(如抑癌基因启动子区)甲基化水平的异常升高,从而导致染色体不稳定、可移动因子激活、原癌基因异常表达和抑癌基因的失活等.目前认为,DNA的异常甲基化(低甲基化与超甲基化)在体细胞癌变进程中扮演着极其重要的角色,肿瘤特异性DNA甲基化标记是一种很有希望的肿瘤早期预警与临床前诊断标记物.     

DNA异常甲基化与肿瘤发生及早期监测

DNA甲基化已成近年表遗传学研究的热点之一.越来越多的研究表明,肿瘤发生发展过程中存在特征性的DNA甲基化紊乱,表现为基因组整体甲基化水平的降低和局部DNA区域(如抑癌基因启动子区)甲基化水平的异常升高,从而导致染色体不稳定、可移动因子激活、原癌基因异常表达和抑癌基因的失活等.目前认为,DNA的异常甲基化(低甲基化与超甲基化)在体细胞癌变进程中扮演着极其重要的角色,肿瘤特异性DNA甲基化标记是一种很有希望的肿瘤早期预警与临床前诊断标记物.     

DNA异常甲基化与肿瘤发生及早期监测

DNA甲基化已成近年表遗传学研究的热点之一.越来越多的研究表明,肿瘤发生发展过程中存在特征性的DNA甲基化紊乱,表现为基因组整体甲基化水平的降低和局部DNA区域(如抑癌基因启动子区)甲基化水平的异常升高,从而导致染色体不稳定、可移动因子激活、原癌基因异常表达和抑癌基因的失活等.目前认为,DNA的异常甲基化(低甲基化与超甲基化)在体细胞癌变进程中扮演着极其重要的角色,肿瘤特异性DNA甲基化标记是一种很有希望的肿瘤早期预警与临床前诊断标记物.     

DNA异常甲基化与肿瘤发生及早期监测

DNA甲基化已成近年表遗传学研究的热点之一.越来越多的研究表明,肿瘤发生发展过程中存在特征性的DNA甲基化紊乱,表现为基因组整体甲基化水平的降低和局部DNA区域(如抑癌基因启动子区)甲基化水平的异常升高,从而导致染色体不稳定、可移动因子激活、原癌基因异常表达和抑癌基因的失活等.目前认为,DNA的异常甲基化(低甲基化与超甲基化)在体细胞癌变进程中扮演着极其重要的角色,肿瘤特异性DNA甲基化标记是一种很有希望的肿瘤早期预警与临床前诊断标记物.     

DNA异常甲基化与肿瘤发生及早期监测

DNA甲基化已成近年表遗传学研究的热点之一.越来越多的研究表明,肿瘤发生发展过程中存在特征性的DNA甲基化紊乱,表现为基因组整体甲基化水平的降低和局部DNA区域(如抑癌基因启动子区)甲基化水平的异常升高,从而导致染色体不稳定、可移动因子激活、原癌基因异常表达和抑癌基因的失活等.目前认为,DNA的异常甲基化(低甲基化与超甲基化)在体细胞癌变进程中扮演着极其重要的角色,肿瘤特异性DNA甲基化标记是一种很有希望的肿瘤早期预警与临床前诊断标记物.     

DNA异常甲基化与肿瘤发生及早期监测

DNA甲基化已成近年表遗传学研究的热点之一.越来越多的研究表明,肿瘤发生发展过程中存在特征性的DNA甲基化紊乱,表现为基因组整体甲基化水平的降低和局部DNA区域(如抑癌基因启动子区)甲基化水平的异常升高,从而导致染色体不稳定、可移动因子激活、原癌基因异常表达和抑癌基因的失活等.目前认为,DNA的异常甲基化(低甲基化与超甲基化)在体细胞癌变进程中扮演着极其重要的角色,肿瘤特异性DNA甲基化标记是一种很有希望的肿瘤早期预警与临床前诊断标记物.     

Secular change in menarche in women in Madrid

The age at menarche was estimated by recollection in 1617 women between the ages of 18 and 60 in Madrid and a nearby suburb, Pinto. The population of Pinto is working-class and the Madrid group, taken from residential neighbourhoods , belongs to the upper middle class. In both groups we found a diminution in average age at menarche, from 14.04 to 13.02 years in Madrid and from 14.55 to 13.16 years from about 1935 to about 1965 in Pinto. These changes have been more intense in the group which is less well-off economically, where living conditions have varied much more drastically.     

Intestinal helminthiasis in school children in Haiti in 2002

A survey on intestinal helminths in school children was conducted in Haiti in 2002. This first nationwide study involving the entire country was stratified by department according to urban and rural zones using the cluster method. Focusing on elementary school children (n=5792; age range 3 to 20 years), it involved 26 urban and 49 rural schools randomly selected. Stools were preserved in formalin and examined by the Ritchie technique. Thirty-four per cent of stools (1981/5792) tested positive for intestinal helminths with the following parasites identified: Ascaris lumbricoides (27.3%), Trichuris trichiura (7.3%), Necator americanus (3.8%), Hymenolepsis nana (2%), Taenia sp. (0.3%) and Strongyloides stercoralis (0.2%). The helminth prevalence was higher in rural (38.4%) compared to urban areas (30%). There was no significant difference in prevalence by sex and age. The importance of geohelminths changed from one department to another with the highest prevalence found in the Southern department of Grande Anse (73.7%) and the lowest prevalence in the Center department (20.6%). Five out of the country's nine departments had a similar prevalence varying from 25.5% to 28.2%. Intestinal helminthic polyparasitism was observed in a percentage of infested school children comprise between 3.4% and 28.6% according in relation to the geographical area. A program to fight against geohelminths in school children should be initiated as a public health priority. Albendazole is the drug of choice. Frequency of drug distribution should be based on the prevalence of geohelminths in each department.     

Experience in adult population in dengue outbreak in Delhi

A dengue outbreak has recently hit the Indian capital. We studied the clinical profile of adult patients. Five hundred and sixty patients of dengue infection were admitted in a specially created ward according to the criteria laid down by WHO. Haematemesis (28.28%), epistaxis (26.78%) and malena (14.28%) were some of the common presentations. Similarly lymphadenopathy, especially cervical (30.89%), palatal rashes (26.96%) and hepatomegaly (23.75%) were the most commonly encountered findings on physical examination. Most of the cases were of dengue fever with haemorrhage and only 2.5% cases were classified under dengue haemorrhagic fever or dengue shock syndrome. The average hospital stay was 3.4 days but only 9.8 hours in the eleven patients who died, suggesting their late arrival in preterminal situation giving little time for resuscitation. Thrombocytopenia was not a feature and only 12.85% patients had platelet count less than 70,000/cmm. Most of the patients who were admitted with thrombocytopenia, showed normalization in their platelet counts in next few days. Serological examination demonstrated evidence of recent dengue infection in 41.17% patients. Few patients required blood or platelet concentrate transfusion. Eleven patients died, three due to DIC, one of intracranial haemorrhage and seven due to massive gastric haemorrhage. Rest of the patients recovered completely. Thus we can conclude that recent outbreak in Delhi was of dengue fever with haemorrhage and mortality was very low in patients who came early to the hospital.     

Changes in the hypothalamic nuclei in in experimental allergy

Summary In rabbits subjected to prolonged sensitization and in which the Arthus phenomenon was induced there was a marked reaction of the hypothalamic nuclei. Staining by Gomori's method indicated a cellular swelling, loss of granules, and protoplasmic vacuolization in the supraoptic nucleus. There was a considerable increase in the size of the cross-sectional area of the cells. The same effects were much less well shown in the paraventricular nucleus. These results show that marked signs of increased neurosecretion developed in the animals at the height of the Arthus phenomenon.(Presented by Active Member AMN SSSR V. V. Parin) Translated from Byulleten Éksperimental'noi biologii i Meditsiny, Vol. 55, No. 4, pp. 110–113, April, 1963.     

Development in in vitro toxicology

There are three principal pressures driving the development of in vitro toxicology: (1) the need for more efficient testing systems to cope with the large number of xenobiotics currently being developed; (2) public pressure to reduce animal experimentation; and (3) a need for a better understanding of the mechanisms of toxicity. Within this, in vitro toxicology is focused on local, systemic, and target-organ toxicity. It is becoming increasingly apparent that a step or decision-tree approach using input of a variety of experimental data (physicochemical properties, biokinetics, cytotoxicity) provides the most efficient system for predicting toxicity. Examples of the use of in vitro toxicity systems for prediction of systemic toxicity and target-organ (liver) toxicity are presented.Originally presented at ECCP 93.