安徽省青少年留守状况的流行病学调查

目的:描述安徽省青少年的留守状况,探索不同类型青少年留守率的差异.方法:采用分层整群抽样的方法抽取皖南、皖北城乡普通中学7所,获得样本3 421人,其中留守青少年682人.自行设计流行病学凋查表对研究对象的一般人口学特征和留守状况进行问卷调查.结果:安徽省10 ～ 18岁青少年的留守率为19.94％.不同类型青少年留守...     

Rickettsia parkeri in Amblyomma americanum Ticks, Tennessee and Georgia, USA

To determine the geographic distribution of the newly recognized human pathogen Rickettsia parkeri, we looked for this organism in ticks from Tennessee and Georgia, USA. Using PCR and sequence analysis, we identified R. parkeri in 2 Amblyomma americanum ticks. This rickettsiosis may be underdiagnosed in the eastern United States.     

Tight and adherens junctions in the ovine uterus: differential regulation by pregnancy and progesterone

In species with noninvasive implantation by conceptus trophectoderm, fetal/maternal communications occur across the endometrial epithelia. The present studies identified changes in junctional complexes in the ovine endometrium that regulate paracellular trafficking of water, ions, and other molecules, and the secretory capacity of the uterine epithelia. Distinct temporal and spatial alterations in occludin, tight junction protein 2, and claudin 1-4 proteins were observed in the endometrium of cyclic and early pregnant ewes. Dynamic changes in tight junction formation were characterized by an abundance of tight junction proteins on d 10 of the estrous cycle and pregnancy that substantially decreased by d 12. Early progesterone administration advanced conceptus development on d 9 and 12 that was associated with loss of tight-junction-associated proteins. Pregnancy increased tight-junction-associated proteins between d 14-16. Cadherin 1 and beta-catenin, which form adherens junctions, were abundant in the endometrial glands, but decreased after d 10 of pregnancy in the luminal epithelium and then increased by d 16 with the onset of implantation. Results support the ideas that progesterone elicits transient decreases in tight and adherens junctions in the endometrial luminal epithelium between d 10-12 that increases selective serum and tissue fluid transudation to enhance blastocyst elongation, which is subsequently followed by an increase in tight and adherens junctions between d 14-16 that may be required for attachment and adherence of the trophectoderm for implantation. The continuous presence of tight and adherens junctions in the uterine glands would allow for vectorial secretion of trophic substances required for conceptus elongation and survival.     

Scent marking behavior as an odorant communication in mice

In rodents, where chemical signals play a particularly important role in determining intraspecies interactions including social dominance and intersexual relationships, various studies have shown that behavior is sensitive to conspecific odor cues. Mice use urinary scent marks for communication with individual conspecifics in many social contexts. Urinary scent involves genetic information about individuals such as species, sex, and individual identity as well as metabolic information such as social dominance, and reproductive and health status, which are mediated by chemical proteins in scent marks including the major histocompatibility complex and the major urinary proteins. The odor of the predator which can be considered to be a threatening signal for the prey also modulate mouse behavior in which scent marking is suppressed in response to the cat odor exposure in mice. These odorant chemicals are detected and recognized through two olfactory bulbs, the role of which in detection of chemosignals with biological relevant appears to be differential, but partly overlapped. Mice deposit scent marks toward conspecifics to maintain their social relationships, and inhibit scent marking in a context where natural predator, cat odor is contained. This suppression of scent marking is long-lasting (for at least 7 days) and context-dependent, while the odorant signaling to conspecifics tends to appear frequently (over 24h but less than 7 days intervals) depending on the familiarity of each signal-recipient. It has been discussed that scent marking is a communicative behavior associated with territoriality toward conspecifics, indicating that the social signaling within species are sensitive to predator odor cues in terms of vulnerability to predation risk.     

苏皖地区汉族人群不稳定型心绞痛患者与血小板反应素4基因A387P多态性的关系

目的:观察血小板反应素4基因G29926C(A387P)多态性与中国苏皖地区汉族人群不稳定型心绞痛的可能关系。方法:选择2004-11/2006-05在南京医科大学第一附属医院和江苏大学附属武进医院住院不稳定型心绞痛患者110例,病例均符合2002年AHA/ACC关于不稳定型心绞痛诊断指南的诊断标准,同期选择337例非冠心病者为对照。酚-氯仿法提取白细胞DNA,应用聚合酶链反应-限制性片段长度多态性方法分析血小板反应素4A387P多态性,取部分PCR扩增产物进一步测序鉴定,比较两组间多态性频率分布差异,探讨血小板反应素4基因多态性与不稳定型心绞痛发病的可能关系。结果:447例均进入结果分析。GC基因型在不稳定型心绞痛组和对照组的分布无统计学差异(5.5%,7.1%,P=0.54),未检测到CC纯合子。C等位基因频率在不稳定型心绞痛组和对照组分别为2.7%,3.6%(P=0.55)。GC基因型与不稳定型心绞痛无显著性关联(OR=0.75,95%CI:0.30￣1.89,P=0.54)。结论:血小板反应素4基因387A→P不是中国苏皖地区汉族人群常见的多态位点,且与不稳定型心绞痛的发病无显著相关性。     

An in vitro evaluation of the WIRELE-x electronic apex locator

This study evaluated the accuracy of the Wirele-X (Forum Tec, Ashkelon, Israel), a novel Bluetooth-enabled wireless electronic apex locator. Thirty-one extracted teeth with mature apices were used. Under 10X magnification, the actual canal lengths were determined. The teeth were embedded in alginate and electronic canal lengths were obtained using the Root ZX II and Wirele-X electronic apex locators. The actual canal lengths and electronic canal lengths were compared with Student's t-test. The average distance from the file tip to the actual canal length was −0.11 mm (±0.16) for the Root ZX II, and − 0.07 mm (±0.21) for the Wirele-X. There were no statistically significant differences between the two electronic apex locators in their ability to determine the actual canal length (p > 0.05). The wireless apex locator (Wirele-X) and the wired apex locator (Root ZX II) were found to be equally accurate.