HPI毒力岛缺失的EAggEC17-2突变菌株的构建及其功能研究

目的 构建HPI毒力岛缺失的EAggEC17-2突变株，初步研究EAggEC菌株携带的耶尔森菌HPI毒力岛合成铁载体Ybt的功能。方法以EAggEC17-2为出发菌株，irp8基因部分序列作为同源重组的一侧序列，irp5基因序列作为同源重组的另一侧序列，中间插入有氯霉素（Can）抗性基因（cat基因）标记。通过接合转移和同源重组，构建了缺失约24kb的HPI毒力岛功能核心区区域EAggEC17-2的仝岛缺失株EA85。应用流式细胞技术（FACS）检测指示菌株WA-CS irp1：：KN（pC3G3．3N）荧光强度的变化情况，对EA85缺失株和出发菌株进行了合成Ybt的功能比较研究。结果成功构建了EAggEC17-2HPI全岛缺失株EA85。EAggEC17-2菌株具有表达Ybt的功能，而缺失株EA85丧失了合成Ybt的能力。结论EAggEC17-2HPI毒力岛的缺失，使Ybt的合成彻底阻断。EAggEC17-2具有的合成Ybt的功能是由其染色体携带的HPI毒力岛所决定的。     

Phylogenetic group B2 Escherichia coli strains from the bowel microbiota of Pakistani infants carry few virulence genes and lack the capacity for long-term persistence

Escherichia coli strains of phylogenetic group B2 obtained from Western human hosts are enriched in virulence-associated genes and have a superior capacity to persist in the colonic microbiota. Here, E . coli strains from 22 infants born in Pakistan whose rectal flora was sampled regularly over the first 6 months of life were examined. B2 strains did not carry the virulence-associated genes sfaD/E , papC , neuB or hlyA more often than strains of other phylogenetic groups . B2 origin was not associated with persistence in the bowel microbiota. As compared with B2 strains from Swedish infants, Pakistani B2 strains carried significantly less often the virulence genes fimH (p 0.04), papC (p 0.02), papG class III (p 0.01), sfaD / E (p ≤0.0001), neuB (p ≤0.0001), and hlyA (p 0.005), and also the high-pathogenicity island (p ≤0.0001). A minority of Pakistani B2 strains belonged to recognized uropathogenic O-groups, which are common among 'Western' B2 strains. Thus, extra-intestinal pathogenicity may be the foremost characteristic of B2 strains colonizing Western populations.     

A composite index to explain variations in poverty, health, nutritional status and standard of living: use of multivariate statistical methods

OBJECTIVES: To calculate the Human Development Index (HDI) and Human Poverty Index (HPI) of Indian states; to trace the indicators useful for finding variations in poverty; and to develop a composite index that may explain variations in poverty, health, nutritional status and standard of living. STUDY DESIGN: Cross-sectional study. METHODS: The HDI and HPI were calculated for different Indian states. A set of possible indicators varying between rich and poor states of India was identified with the use of discriminant function analysis. A composite index has been developed for measuring the standard of living of Indian states with the help of factor analysis. RESULTS: Demographic, socio-economic, health and dietary indicators play a major role in determining the real standard of living. Poverty, standard of living and human development depend on multiple factors. The existing indices, such as HDI and HPI, use income indicators to measure the standard of living, and do not take into account diet and nutritional status indicators. The proposed index was found to be more suitable for measuring the real standard of living and human development, as it is a comprehensive index of income and non-income indicators. Further validation may be carried out for different populations. CONCLUSIONS: Discriminant function analysis and factor analysis were used to assess health inequality and standard of living among Indian states. The proposed multi-dimensional index may provide a better picture of human development. Further work is of interest for other populations.     

Effects of hallucinogenic agents mescaline and phencyclidine on zebrafish behavior and physiology

Mescaline and phencyclidine (PCP) are potent hallucinogenic agents affecting human and animal behavior. As their psychotropic effects remain poorly understood, further research is necessary to characterize phenotypes they evoke in various animal models. Zebrafish (Danio rerio) are rapidly emerging as a new model organism for neuroscience research. Here, we examine the effects of mescaline (5-20mg/l) and PCP (0.5-3mg/l) in several zebrafish paradigms, including the novel tank, open field and shoaling tests. Mescaline and PCP dose-dependently increased top activity in the novel tank test, also reducing immobility and disrupting the patterning of zebrafish swimming, as assessed by ethograms. PCP, but not mescaline, evoked circling behavior in the open field test. At the highest doses tested, mescaline markedly increased, while PCP did not affect, zebrafish shoaling behavior. Finally, 20mg/l mescaline did not alter, and 3mg/l PCP elevated, whole-body cortisol levels. Overall, our studies indicate high sensitivity of zebrafish models to hallucinogenic compounds with complex behavioral and physiological effects.     

Modified Rat Hepatocellular Carcinoma Models Overexpressing Vascular Endothelial Growth Factor

Purpose

To compare tumor vascularity in 4 types of rat hepatocellular carcinoma (HCC) models: N1S1, vascular endothelial growth factor (VEGF)-transfected N1S1 (VEGF-N1S1), McA-RH7777, and VEGF-transfected McA-RH7777 (VEGF-McA-RH777) tumors.

Unpredictable chronic stress model in zebrafish (Danio rerio): behavioral and physiological responses

Zebrafish (Danio rerio) have emerged as a promising model organism to study development, toxicology, pharmacology, and neuroscience, among other areas. Despite the increasing number of studies using zebrafish, behavioral studies with this species are still elementary when compared to rodents. The aim of this study was to develop a model of unpredictable chronic stress (UCS) in zebrafish. We evaluated the effects of UCS protocol during 7 or 14 days on behavioral and physiological parameters. The effects of stress were evaluated in relation to anxiety and exploratory behavior, memory, expression of corticotrophin-releasing factor (CRF) and glucocorticoid receptor (GR), and cortisol levels. As expected, UCS protocol increased the anxiety levels, impaired cognitive function, and increased CRF while decreased GR expression. Moreover, zebrafish submitted to 7 or 14 days of UCS protocol presented increased cortisol levels. The protocol developed here is a complementary model for studying the neurobiology and the effects of chronic stress in behavioral and physiological parameters. In addition, this protocol is less time consuming than standard rodent models commonly used to study chronic stress. These results confirm UCS in zebrafish as an adequate model to preclinical studies of stress, although further studies are warranted to determine its predictive validity.     

山东省腹泻病人携带耶尔森菌HPI毒力岛大肠杆菌的调查

目的 了解携带耶尔森菌HPI毒力岛的大肠杆菌的易感人群、感染率、临床症状、分离率。方法 对4个医院1997年6～11月就诊泻患者,进行流行病学调查并收集大便标本,进行细菌分离和鉴定。结果 在671例腹泻病人中,共检出20个属种449株致病毒,志贺菌检出率为25.48%,致泻性大肠杆菌为15.05%,对于176株疑似产志贺样毒素且具侵袭大肠杆菌(ESIEC)菌株采用irp-2、irp-B基因探针进行菌落原位杂交,检出42株携带HPI毒力岛的大肠杆菌。与42株携带HPI毒力岛的大肠杆菌相关的腹泻病人所表现的临床症状为食欲不振、腹痛、腹泻、寒战、乏力、体温正常或低热,粪例多为粘液便或水样便,日腹泻次数超过6次以上者为33例,占78.57%。各年龄组均有感染,10岁以下儿童为主,占33.33%.结论 自671例腹泻病人的粪便标本中,分离到的志贺菌占首位,致泻性大肠杆菌次之;在致泻性大肠杆菌以携带耶尔森菌HPI毒力岛的大肠杆菌为主(6.26%)。     

Using cerebral ultrasound effectively in the newborn infant

Cranial ultrasound is the most available and easily repeatable technique for imaging the neonatal brain. Its quality and diagnostic accuracy depend on various factors; the suitability of the ultrasound machine for neonatal cranial work, the use of optimal settings and probes, appropriate scanning protocols, the use of a variety of acoustic windows and, not least, the scanning experience of the examiner. Knowledge of normal anatomy and the echogenicities of different tissues in normal and pathological situations as well as familiarity with the physiological and pathological processes likely to be encountered is vital. This paper assesses the value and appropriate use, safety and diagnostic accuracy of modern, high-quality ultrasound in evaluating the brain of the preterm and term born infant. Issues of concern regarding teaching, supervision and experience of the examiner are also addressed.     

Aggression in rainbow trout is inhibited by both MR and GR antagonists

The present study has investigated the effect of exogenous cortisol on aggression in juvenile rainbow trout, along with the involvement of mineralocorticoid (MR) and glucocorticoid receptors (GR) mediating the effects of cortisol. Fish were fed pellets supplemented with cortisol, the GR antagonist mifepristone (RU486) in combination with cortisol, the MR antagonist spironolactone (SA) in combination with cortisol or both antagonists in combination with cortisol. Aggressive behaviour was then assessed 1 h subsequent to feeding. Our results showed that the attack latency was increased by exogenous cortisol, an effect that was not abolished by the antagonists. The intensity of aggression was not changed by exogenous cortisol. However, the intensity of aggression was significantly reduced by both antagonists. These results are discussed with regard to cortisol affecting aggressive behaviour through genomic and non-genomic pathways. Our results have demonstrated the involvement of both MR and GR in regulating behavioural responses during social interactions in teleost fish. The intensity of aggression seen in control and cortisol treated fish is probably mediated by the basal levels of cortisol through the intracellular MRs and GRs. We conclude that the initiative to engage in social confrontations is mediated through a non-genomic pathway, which could involve extracellular corticoid receptors. Further, the majority of arguments lean towards the MR and GR antagonists blocking the effect of cortisol on aggressive intensity through intracellular receptors. If this is the case, then it is probable that these two aspects of aggressive behaviour are based on different neuronal mechanisms.     

致病性大肠埃希菌高致病性毒力岛irp2基因序列的扩增与分析

目的探讨致病性大肠埃希菌（EPEC）中高致病性毒力岛（HPI）irp2基因与致病性的关系。方法根据Genebank中irp2基因设计特异性引物，应用聚合酶链反应（PCR）技术扩增基因全长，克隆入pUCm-T载体，并通过酶切和测序鉴定。结果160株EPEC中有16株（10．00％）扩增出278bp基因片段，该基因片段与GeneBank中公布的耶尔森菌HPI irp2基因的同源性高达97％以上。结论部分EPEC具有耶尔森菌毒力岛HPI基因序列，该毒力岛可能与EPEC的致病性有一定相关性。