Genomic integration and expression of the Aggregatibacter actinomycetemcomitans catalase gene in Aggregatibacter aphrophilus

ObjectiveTo test the hypothesis that virulence genes of Aggregatibacter actinomycetemcomitans can be expressed and confer fitness advantages in the closely related Aggregatibacter aphrophilus.DesignClinical isolates of A. aphrophilus were screened for natural competence with marked genomic DNA from A. actinomycetemcomitans and A. aphrophilus. The gene katA of A. actinomycetemcomitans D7S-1 and its flanking regions were constructed and inserted into a comparable locus in the genome of a naturally competent A. aphrophilus strain by a markerless protocol via natural transformation. Mutants of A. actinomycetemcomitans with or without katA were also constructed by a similar protocol. Discs soaked with either 0.03% hydrogen peroxide or broth culture of Streptococcus gordonii Challis were placed on the agar with cultures of A. actinomycetemcomitans or A. aphrophilus. The size of the growth inhibition zone associated with the disc was measured after 2-day culture.ResultsFive of the 13 A. aphrophilus strains exhibited a transformation frequency of 10⁻⁶ or higher. The intra- and inter-species transformation frequencies were comparable. The inhibition zones for katA-negative strains of A. actinomycetemcomitans or A. aphrophilus were 3- to 7-fold larger than those associated with katA-positive strains (p < 0.05).ConclusionsThere was no apparent species barrier for the transfer and expression of A. actinomycetemcomitans katA in A. aphrophilus. The inserted A. actinomycetemcomitans-specific katA gene in A. aphrophilus strain NJ8700 conferred resistance to inhibition by hydrogen peroxide or S. gordonii. The potential to swap genes between these two closely related oral species may be an alternative approach for investigating the virulence determinants of A. actinomycetemcomitans.     

散发性大肠癌CpG岛甲基子表型的基因表达

目的探讨CpG岛甲基子表型阳性的散发性大肠癌的基因表达特征。方法对71例散发性大肠癌采用甲基化特异性PCR法行p14ARF、人类mut-s同系物1(hMLH1)、p16INK4a、6-氧-甲基鸟嘌呤-DNA甲基转移酶(MGMT)和肿瘤甲基化位点1(MINT1)共5个基因启动子甲基化的检测,确定CpG岛甲基子表型;进行K-ras、APC、P53、Bax和转化生长因子βⅡ受体(TGFβRⅡ)共5个基因的免疫组化检测。分析散发性大肠癌CpG岛甲基子表型和基因表达之间的关系。结果71例散发性大肠癌中,CpG岛甲基子表型阳性率为21．1％(15／71);K-ras、APC、P53、Bax和TGFβRⅡ蛋白阳性表达率分别为43．7％(31／71)、42．3％(30／71)、47．9％(34／71)、71.4％(50／70)和59．2％(42／71)。CpG岛甲基子表型和APC、P53、Bax、TGFβRⅡ蛋白表达均无显著相关性,但与K-ras蛋白表达显著相关,CpG岛甲基子表型阳性者K-ras蛋白阳性表达率显著高于CpG岛甲基子表型阴性者(66.7％比37．5％, P=0．043)。结论CpG岛甲基子表型阳性的散发性大肠癌中K-ras蛋白呈高表达,提示多基因同时甲基化与K-ras蛋白的激活表达密切相关,两者的关系表明表遗传学机制可以间接引起遗传学改变。     

驻岛官兵自我效能感与职业倦怠感的相关研究

目的探讨驻海岛官兵的一般自我效能感与职业倦怠感的相关关系,为官兵心理健康教育提供理论依据。方法采用一般自我效能感量表（General Self—Efficacy Scale,GSES）、职业倦怠感量表（Maslach Burnout Inventory,MBI）,对某海防部队的328名驻岛官兵进行调查。结果①驻岛官兵职业倦怠感中情感耗竭感、去个性化、个人成就感得分依次为（20．68±6．52）、（7．08±3．8）、（33．78±9．65）分,提示中、低度倦怠;②自我效能感得分为（12．58±5．61）分;③自我效能感得分与情绪衰竭感（t=-0．19～-0．23,P〈0．05）、去个性化得分呈显著负相关（t=-0．18- -0．22,P〈0．05）,与个人成就感得分呈显著正相关（t=0．18～0．23,P〈0．05）。结论驻岛官兵存在一定程度的职业倦怠现象,提高自我效能感有助于改善驻岛官兵的职业倦怠。     

肺癌患者PTEN基因启动子高甲基化的检测

目的 探讨肺癌患者组织、外周血浆及支气管肺泡灌洗液(BALF)中张力蛋白同源的磷酸酶基因(PTEN)启动子异常基因化状况及其在肺癌诊断中的价值.方法 用甲基化特异性PCR方法检测组织、血浆及BALF中的PTEN基因启动子区CpG岛甲基化.结果 45例肺癌患者中,PTEN基因启动子异常甲基化率组织为26.67%(12/45)、血浆为15.56%(7/45),BALF为22.22%(10/45);而非肺癌组织、正常对照血浆、非肺癌患者BALF中未检出甲基化;血浆、BALF中甲基化改变与肿瘤组织甲基化状况显著相关(P<0.01).结论 血浆、BALF中PTEN基因异常甲基化改变的检测在肺癌的早期特异诊断等方面有一定的价值.     

Burkholderia thailandensis Isolated from the Environment,United States

Burkholderia thailandensis, an opportunistic pathogen found in the environment, is a bacterium closely related to B. pseudomallei, the cause of melioidosis. Human B. thailandensis infections are uncommon. We isolated B. thailandensis from water in Texas and Puerto Rico and soil in Mississippi in the United States, demonstrating a potential public health risk.     

Symtoms and Social Adjustment of Schizophrenic Patients as Evaluated by Their Family Members: A Cross-Cultural Psychiatric Study between Offshore Islands and an Urban City

Abstract: We conducted a comparative study of symptoms and social adjustment of schizophrenic patients on offshore islands and one urban region in Japan. In the evaluation of symptoms and social behavior by family members, no differences were observed between the two regions. Looking at social adjustment in the two regions, no differences were observed by family members either in the performance level or in the expectation level of socially expected activities. However, on the offshore islands, the expectation level of socially expected activities by family members was significantly higher than the level of self-accomplishment set by schizophrenic patients themselves. As for leisure activities, both family members and patients on the islands evaluated the level of performance to be significantly higher than in the urban region, and the level of satisfaction of the patients themselves was also higher on the islands. Considering both these findings and Japanese traditional views of work and leisure, it is believed that on the islands patients are required to engage in more productive activities and less leisure activities than in the urban region. Further it seems that patients on the islands compared to patients in the urban region may have greater difficulty in social adjustment.     

Health and welfare in St Helena: the contribution of W.J.J. Arnold, Colonial Surgeon, 1903–1925

St Helena is a remote south Atlantic island subject to insular problems of isolation and economic weakness which impact on health and welfare. It has long been British and in 1900 was used as a prison camp for Boers. One of the medical team looking after them was W.J.J. Arnold who remained on the island, as Colonial Surgeon and Acting Governor until his death in 1925. This paper considers the then health and welfare problems of this underdeveloped, isolated population and investigates their amelioration with reference to the work of Dr Arnold.     

Selection Pressure and Altered Hepatocellular Islands after a Single Injection of Aflatoxin B1

Development of glutathione S-transferase placental form (GST-P)-positive focal populations was investigated subsequent to single injections of the hepatocarcinogens aflatoxin B1 (AfB1), dimethylnitrosamine (DMN) and diethylnitrosamine (DEN). While DEN proved far more potent at inducing putative initiated hepatocytes, the AfB1 treatment was associated with a very rapid (3 weeks) development of lesions approaching nodular proportions. Autoradiographic investigation revealed selective incorporation of label into GST-P-positive hepatocytes and oval cells at the day 7 time point following AfB1 treatment. Administration of butylated hydroxyanisole (BHA) subsequent to carcinogen injection was associated with a decrease in the final yield of lesions and increased tritiated thymidine incorporation in perivenular zone 3 background hepatocytes. The results suggest that 'selection pressure', resulting in rapid growth and development of putative preneoplastic lesions, is inherent in a single injection of the mycotoxin and indicate that variations of the present short-term model may be useful for elucidating the mechanisms underlying AfB1-induced hepatocarcinogenesis.     

两类远岛环境对守卫战士记忆能力的影响

目的探讨两类远岛环境对不同类型守卫战士注意力的影响。方法运用国际标准的韦克斯勒成人记忆量表(WMS)中国修订版中的3个分测验,分别是图片回忆能力测验、视觉再认能力测验、联想记忆能力测验,对两类远岛守卫战士和大陆上的对照组进行个别测量。结果对照组与远小岛、远中心岛不同类型战士视觉再认、图片回忆组间差异不具有显著的统计学意义(P0.05),联想记忆仅远小岛一年兵在简单部分测量结果比对照组要低,差异具有显著的统计学意义(P0.05),联想记忆复杂部分仅远小岛二年兵测量结果比对照组要高,差异具有显著的统计学意义(P0.05),其余差异都不明显;结论远岛环境对守卫战士记忆能力的影响不明显。