p16和Rb基因甲基化与胃癌关系研究进展

胃癌是我国最常见的恶性肿瘤之一 ,每年死于胃癌者 2 5 .1 6/ 1 0万 ,居恶性肿瘤首位 ,严重危害人类的健康。胃癌发生与DNA合成及核酸代谢旺盛密切相关 ,其发生机制复杂 ,它是病毒、化学致癌物质等多病因共同作用 ,经启动、促进、演进等多阶段发病过程 ,推测有多种基因发生改变 ,其中包括癌基因的激活及抗癌基因的失活等 ,共同引起细胞生长失控。引起基因表达异常的机制有两种[1 ] :一为基因机制 ,即DNA结构改变学说 ,认为癌变是由于致癌物质使DNA结构发生改变 ,包括基因缺失、突变等引起基因转录或结构异常的基因产物。二为表基因机制 …     

原位RT-PCR检测Ig A样新基因SNC66在消化系统肿瘤组织中的表达

目的：探讨原位检测内源性基因表达产物的灵敏方法，研究IgA样新基因SNC66在消化系统肿瘤组织中的表达及其与肿瘤之间的相关性。方法：在组织切片原位逆转录反应后进行原位PCR扩增，在扩增过程中掺入地高辛标记的尿核苷酸，再用免疫组织化学的方法加以检测。比较SNC66在大肠癌、胃癌、肝癌组织与相应的正常配对组织中的表达情况。结果：10个循环时，37例大肠癌标本中有14例呈阴性，18例弱阳性，5例强阳性；20例胃癌标本中有6例呈阴性，9例弱阳性，5例强阳性；所有肝脏组织和肝癌标本都呈阴性表达。25个循环时，大肠癌10例阴性，27例强阳性；胃癌4例阴性，16例强阳性；所有肝脏组织和肝癌组织标本都呈阳性表达。相应大肠粘膜和胃粘膜标本则无论是25个循环，还是10个循环，都呈强阳性表达，但着色程度前者高于后者。结论：原位RT-PCR是一种检测内源性基因低拷贝转录产物mRNA的灵敏方法。基因SNC66是一个消化道肿瘤相关性基因，在大肠癌和胃癌组织中存在明显的表达降低或缺陷，但与肝癌之间不存在相关性。SNC66可作为侯选的消化道肿瘤的抑癌基因加以进一步研究。     

细胞凋亡相关基因P_(53)、Fas在胃癌中表达的研究进展

目前关于细胞凋亡相关基因与胃癌的关系,正在成为当前胃癌研究领域中的热点之一。为探讨其在胃癌的发生、发展、早期诊断、治疗及预后评价中的作用,本文将细胞凋亡相关基因P_(53)、Fas在胃癌中的表达作一简要概述。 1 细胞凋亡的概念及基因调节 细胞凋亡(apoptosis)(凋谢或凋零),该词源自古希腊语,指秋天树叶凋落。1972年英国学者Kerr等首先把这一术语引入生物学,用以描述一种不同于细     

胃粘膜良恶性病变中bcl-2、bax、c-myc基因蛋白表达及意义

为探讨凋亡相关基因bcl-2、bax、c-myc在胃癌发生发展中的作用,我们采用SP免疫组织化学方法对125例胃粘膜良恶性病变标本进行bcl 2、bax、c-myc基因蛋白的检测。结果表明,bcl-2和bax在胃癌、胃炎伴肠化生和异型增生组的阳性表达率显著高于单纯胃炎组,且bcl-2的表达与胃癌分化程度有关。此实验提示bcl-2、bax和c-myc基因可能参与胃癌的发生和发展。     

青少年健康危险行为相关因素分析综述

青少年健康危险行为主要包括意外伤害行为、吸烟行为、饮酒和药物使用行为、性行为、饮食和锻炼行为、网络成瘾行为等，主要影响因素有家庭、学校、同伴、社会和个体心理特征，可分为危险因素和保护因素两类，对青少年健康危险行为的研究日益受到重视，问题行为理论是最有影响的理论模型，深入地研究危险行为发生的心理机制及影响因素，有利于更好地促进青少年的健康成长。     

麻烦的真相：拯救人类，还有十年：“可茵可音”——一位留美学者有关科学教育的博客

新思考物理课程网（http：／／phys．cersp．com）特邀可茵女士介绍国外科学教育的有关信息。可茵女士将首先通过个人博客“可茵可音”为我们介绍有关美国民众科学意识、科普动态，美国中小学及大学科学教育现状等系列信息.希望老师们能愉快地享受阅读,参与讨论。 “可茵可音”博客网址：http：／／blog．cersp．com／85158．aspx[编者按]     

彩色马蹄莲种球采收处理技术

为了控制彩色马蹄莲种球采收后的严重病害，试验研究了采收前55d、40d、25d控制给水，种球消毒处理及芽眼朝向和分层摆放等方法。发现采收前40d开始控水有利于保证种球的质量，减少软腐病害；种球消毒处理可降低细茵性软腐病，但却增加了真菌病害感染的机会；种球芽眼朝下、单层摆放比芽眼朝上和多层摆放更有利于控制病害。种球采收后迅速风干是最关键的技术措施，采前控水是减少病害发生的生理基础，芽眼朝下和单层摆放可保证种球长期贮藏。     

南阳市部分绿化树木除菌作用的研究

用培养基培养法对南阳市市区空气含茵量进行测定，用统计多元素方差分析法分析影响南阳市绿化树木除茵作用主要影响因子。研究结果表明：绿化树木有很好的除茵作用，其除茵能力与树种、发育期、群落类型等因素有关。     

DNA并非遗传的全部

众所周知，DNA是遗传信息的携带，遗传现象主要是由基因决定的。但是，近几年来科学家发现，朊病毒是一种可遗传的蛋白质粒子；DNA甲基化也导致一些遗传现象的发生；性状间的相互制约也可引起不受基因控制的表型出现……这些现象说明DNA并非遗传的全部。     

童年期虐待对中职学生吸烟饮酒赌博行为的影响

为调查童年期虐待对中职学生吸烟、饮酒、赌博行为的影响,为中职学生危险行为的教育提供参考,采用方便取样,抽取重庆市某区两所中等职业学校学生3571人参加问卷调查,计数资料组间比较采用卡方检验,多因素Logistic回归分析童年期虐待对吸烟饮酒赌博的影响。结果显示：中职学生吸烟、饮酒、赌博的发生比例为16.4%、18.4%、4.6%,遭受情感虐待、躯体虐待、性虐待、情感忽视、躯体忽视比例分别为6.4%、8.7%、9.0%、24.6%、35.6%。男生、一年级学生、父母婚姻不良学生、遭受情感虐待、躯体虐待、情感忽视、躯体忽视学生的吸烟、饮酒、赌博发生比例均分别显著高于对应组;父亲学历高中及以下者的赌博发生比例显著高于对应组,母亲学历高中及以下者饮酒比例显著高于对应组,遭受性虐待者吸烟、赌博发生比例高于对应组。躯体忽视是中职学生吸烟、赌博的危险因素,情感虐待是中职学生饮酒的危险因素。结论：遭受不同类型童年期虐待对中职学生吸烟饮酒赌博行为的影响不同,遭受躯体忽视的学生更易出现吸烟和赌博行为,遭受情感虐待的学生更易出现饮酒行为。     

Conscientiousness explains the link between childhood neglect and cigarette smoking in adults from a low-income,urban area–the differential effects of sex

Cigarette smoking represents the leading cause of preventable morbidity and mortality in the US and understanding its risk factors remains a critical public health endeavor. Low-income individuals and individuals with a history of childhood maltreatment are at heightened risk for cigarette smoking, yet the underlying factors between this association are understudied. Conscientiousness is one construct with potential explanatory relevance to both smoking and childhood neglect. The current investigation examined the association between childhood physical and emotional neglect with smoking (i.e., self-reported cigarette smoking and breath carbon monoxide levels) via conscientiousness. The sample was comprised of 115 adults (M_age = 50.46, SD_age = 5.86; 76.4% Black) recruited from a community center serving low-income and homeless individuals. Mediation analyses showed the indirect effect of childhood emotional neglect on cigarette smoking through conscientiousness; for physical neglect, this relationship was only present among males. The current study provides preliminary evidence that conscientiousness may be a particularly important vulnerability factor when examining the association between childhood neglect and smoking.     

Effects of acute shock on body weight are mediated by changes in food intake

We examined the causal role of decreased food intake in the body weight pattern observed after exposure to intermittent footshock. In Experiment 1, relative to controls, shocked animals decreased food intake and lost weight in the 24-h test. An unshocked group whose food intake was yoked to the shocked group (food-yoked group) for the poststress period revealed that food intake was a sufficient cause of the body weight loss. In Experiment 2, after the first 24 h, the shock group recovered food intake and body weight gain but did not compensate for the initial losses. Body weights of food-yoked animals again indicated that food intake was a sufficient cause of these effects. The lowered body weight of shocked animals at the end of testing was due to a transient hypoingestion and a failure to subsequently show a compensatory hyperingestion. Dess’s (1991) regulatory shift hypothesis is refined in the light of these findings.     

Java软引用防止内存泄漏技术的研究

GC自动地进行内存管理,但长时间对象强引用而忘了释放,可能导致内存泄漏,软引用有较强的引用功能,在程序中申请内存时,GC自动判断是否处于软可及状态的对象。当内存不够时才回收这些由软引用的对象,从而保证了内存不溢出。     

食品中亚硫酸盐使用及检测方法的研究进展

亚硫酸盐是一类在食品中广泛使用却常被忽视的添加剂,不恰当的使用会对人体造成一定的损伤.笔者综述了食品中亚硫酸盐的使用及检验方法,并讨论了各种检测方法的优缺点.旨在对食品生产过程中亚硫酸盐的使用及检测起到一定的指导作用.     

Are Older Adults Prepared to Ensure Food Safety During Extended Power Outages and Other Emergencies?: Findings from a National Survey

Natural disasters and other emergencies can cause an increased risk of foodborne illness. We conducted a nationally representative survey to understand consumers’ knowledge and use of recommended practices during/after extended power outages and other emergencies. Because older adults are at an increased risk for foodborne illness, this paper presents findings from a sample of older adults (n = 290). Only 17% of respondents reported they are fully prepared to keep food safe during an extended power outage. Respondents identified lack of cogitation (42%), storage space (19%), and concern (27%) as barriers to not being fully prepared. Of those who had experienced a recent power outage, less than 40% followed the recommended practices of discarding frozen foods that had thawed and discarding refrigerated, perishable foods. Additionally, 21% to 36% of respondents reported they tasted food to determine whether it was safe to eat. Awareness and likelihood of following recommended practices were higher among women than men. Many older adults are not following recommended practices to ensure food safety during/after extended power outages and other emergencies. Educational materials need to address barriers and be tailored to specific locations and subpopulations of older adults. Educators and public health officials can use the survey findings to address gaps in older adults’ knowledge and practices and to help reduce the risk of foodborne illness among older adults.     

3621名学龄前儿童血铅测定结果分析

[目的]了解儿童血铅水平及其影响因素。[方法]采用全血锌原卟啉值测定;问卷调查影响儿童血铅水平的相关因素,并进行多元逐步回归分析。[结果]3621名儿童平均血铅浓度为0.504umol/L。超过0.483umol/L共有1615人,占44.6％,多元逐步回归分析表明饭前不洗手、常玩金属或带油漆的玩具、使用含铅量高的学习和生活用具、常吃含铅量高食品、父母吸烟等因素与儿童血铅水平密切相关。[结论]儿童血铅含量水平与不良的生活习惯及生活环境的铅污染有关,应对影响儿童血铅水平的危险因素进行有效的预防。     

抵制肥胖

美国第一夫人米歇尔·奥巴马一直领导一场名为“让我们动起来”的遏制儿童肥胖症的全国运动。她有关如何帮助孩子维持健康体重的计划由4部分组成：为家长在选择食品方面提供更多信息,帮助学校食堂向中小学生供应更加健康的食物,使人们在社区里能够更容易买到健康食物,鼓励青少年多参加体育活动。     

Man vs. Machine: A Junior‐Level Laboratory Exercise Comparing Human and Instrumental Detection Limits

The human nose is a very sensitive detector and is able to detect potent aroma compounds down to low ng/L levels. These levels are often below detection limits of analytical instrumentation. The following laboratory exercise is designed to compare instrumental and human methods for the detection of volatile odor active compounds. Reference standards of 3‐mercapto‐1‐hexanol (3MH), a secondary thiol that is important to food quality, are analyzed by gas chromatography with flame ionization detection (GC‐FID), and these raw data are provided to students. Students also perform a series of 3‐alternative forced choice (3‐AFC) sensory tests to determine the human detection limits in a series of samples. For both data sets, 2 methods of data analysis (standard deviation of the response and the slope and signal‐to‐noise ratio for GC‐FID data; forced‐choice ascending concentration series method of limits and linear regression for 3‐AFC data) will be used to estimate instrumental detection limits and human thresholds. GC‐FID and 3‐AFC results are then compared by the students to demonstrate the importance of instrumental and human methods for food analysis, and to provide an experiential learning opportunity to critically think through multiple methods of analysis and compare the outcomes of those methods. In completing the laboratory exercise and discussion questions, students will gain an understanding of the advantages and disadvantages of human and instrumental measurements in food analysis, and compare the outcome of common data analysis methods for instrumental and sensory data.     

Influence of childhood abuse and neglect subtypes on late-life suicide risk beyond depression

The association of childhood maltreatment and suicide has been extensively examined within the population. Depression figures as a main cause for the elevated suicide rate in advanced ages and is often related to childhood maltreatment. The purpose of the present study was to examine the relationship between childhood maltreatment subtypes and suicide risk, testing geriatric depression as a moderator. This is a cross-sectional study looking at a sample of 449 individuals 60 year s old or older from the Multidimensional Study of the Elderly of Porto Alegre Family Health Strategy, Brazil (EMI-SUS/POA). Childhood maltreatment (Childhood Trauma Questionnaire), geriatric depressive symptoms (Geriatric Depression Scale), and suicide risk (Mini International Neuropsychiatric Interview) were assessed. The subtypes of childhood abuse and neglect were significantly associated with suicide risk. In the multivariate analysis, controlling for age, gender, income, marital status, ethnicity, smoking, and geriatric depression symptoms, all trauma subtypes remained associated with suicide risk with the exception of physical neglect (EA = 3.65; PA = 3.16; SA = 5.1; EN = 2.43; PN = 1.76). The present study showed that childhood maltreatment subtypes predicted suicide risk, and geriatric depression does not directly mediate this relation.