Total coliform and E. coli in public water systems using undisinfected ground water in the United States

Public water systems (PWSs) in the United States generate total coliform (TC) and Escherichia coli (EC) monitoring data, as required by the Total Coliform Rule (TCR). We analyzed data generated in 2011 by approximately 38,000 small (serving fewer than 4101 individuals) undisinfected public water systems (PWSs). We used statistical modeling to characterize a distribution of TC detection probabilities for each of nine groupings of PWSs based on system type (community, non-transient non-community, and transient non-community) and population served (less than 101, 101–1000 and 1001–4100 people). We found that among PWS types sampled in 2011, on average, undisinfected transient PWSs test positive for TC 4.3% of the time as compared with 3% for undisinfected non-transient PWSs and 2.5% for undisinfected community PWSs. Within each type of PWS, the smaller systems have higher median TC detection than the larger systems. All TC-positive samples were assayed for EC. Among TC-positive samples from small undisinfected PWSs, EC is detected in about 5% of samples, regardless of PWS type or size. We evaluated the upper tail of the TC detection probability distributions and found that significant percentages of some system types have high TC detection probabilities. For example, assuming the systems providing data are nationally-representative, then 5.0% of the ～50,000 small undisinfected transient PWSs in the U.S. have TC detection probabilities of 20% or more. Communities with such high TC detection probabilities may have elevated risk of acute gastrointestinal (AGI) illness – perhaps as great or greater than the attributable risk to drinking water (6–22%) calculated for 14 Wisconsin community PWSs with much lower TC detection probabilities (about 2.3%, Borchardt et al., 2012).     

应用实时定量PCR进行肿瘤表达研究中内参基因的选择

实时定量PCR(real-time quantitative PCR,RT-qPCR)是检测肿瘤基因表达水平的一种有效方法,在其中应用较多的相对定量方法需要一种能够在不同的组织、甚至不同的实验条件下表达恒定的理想的内参基因.但是很多研究都已经表明内参基因的表达是可变的.所以为了获得适用于肿瘤表达研究的内参基因,越来越多的研究在近期涌现出来.该文将会对近期关于肿瘤表达研究中内参基因选择的文章进行综述.     

AXIN2 Polymorphisms,the β-Catenin Destruction Complex Expression Profile and Breast Cancer Susceptibility

Background: The Wnt/β-catenin signaling pathway is an important regulator of cellular functions suchas proliferation, survival and cell adhesion. Wnt/β-catenin signaling is associated with tumor initiation andprogression; β-catenin mutations explain only 30% of aberrant signaling found in breast cancer, indicating thatother components and/or regulation of the Wnt/β-catenin pathway may be involved. Objective: We evaluatedAXIN2 rs2240308 and rs151279728 polymorphisms, and expression profiles of β-catenin destruction complexgenes in breast cancer patients. Materials and Methods: We collected peripheral blood samples from 102 breastcancer and 102 healthy subjects. The identification of the genetic variation was performed using PCR-RFLPsand DNA sequencing. RT-qPCR was used to determine expression profiles. Results: We found significantassociation of AXIN2 rs151279728 and rs2240308 polymorphisms with breast cancer risk. Significant increasewas observed in AXIN2 level expression in breast cancer patients. Further analyses showed APC, β-catenin,CK1α, GSK3β and PP2A gene expression to be associated to clinic-pathological characteristics. Conclusions:The present study demonstrated, for the first time, that AXIN2 genetic defects and disturbance of β-catenindestruction complex expression may be found in breast cancer patients, providing additional support for rolesof Wnt/β-catenin pathway dysfunction in breast cancer tumorigenesis. However, the functional consequencesof the genetic alterations remain to be determined.     

幽门螺杆菌向“存活但不可培养”状态转变的影响因素研究

目的 探究幽门螺杆菌（Hp）在不同环境下转变为“存活但不可培养（VBNC）”状态的条件，为Hp的潜在传播积累资料。方法 将标准菌株ATCC 43504和临床分离株Hp44、Hp65菌悬液分别用氧胁迫、热力、紫外线照射和微波处理。采用活菌计数，PMA - qPCR、LIVE/DEAD染色、革兰染色、RT - qPCR共同检测Hp VBNC态生成、形态改变及毒力基因的表达。结果 氧胁迫40～48 h时，Hp菌悬液中均有VBNC态菌体，由“S”型向球状转变，毒力基因的表达随着VBNC态的形成而降低。Hp菌悬液分别在56℃加热10 min，80℃加热1 min时，均有菌体以VBNC态存活，80℃加热5 min，100℃加热1 min时所有菌体被杀灭。紫外线分别照射20 min、30 min时，Hp菌悬液中均有菌体以VBNC态存活。微波处理15 s时，菌体以VBNC态存活，当处理时间≥30 s时，所有Hp菌体均被杀灭。结论 Hp能够在氧胁迫、热力、紫外线照射和微波处理的条件下转变为VBNC态，其在环境中的存活情况、检出率和潜在致病性值得进一步研究。     

Development and evaluation of a RT-qPCR assay for fast and sensitive rabies diagnosis

Rabies virus is endemic to Russia, among other countries. It is therefore critical to develop a high-quality and high-precision diagnostic procedure for the control and prevention of infection.The main objective of the research presented here was to develop a reliable RT-qPCR assay for rabies diagnostics.For this purpose, a RABV strains from various biological and geographical origins were used. In addition, rabies-positive and rabies-negative samples, as well as nucleic acids from other viruses and DNA extracted from the brain tissues of mice, dogs, cats, bats and humans, were studied using the developed assay.The analytical sensitivity of the assay, as assessed using armored recombinant positive control dilutions, was 10³ copies/ml, and the sensitivity measured using characterized strains was between 0.1 LD50/ml and 1.0 LD50/ml. A broad range of RNA from RABV strains circulating in different regions of Russia, as well as RNA from RABV-positive primary brain samples from 81 animals and two humans, was detected using the developed assay. No false-positive or false-negative results were obtained.Given that high analytical and diagnostic sensitivities and a high specificity were verified for this assay, it has high potential as a screening test that may be suitable for the epizootiological monitoring of animals and for the fast postmortem diagnosis of rabies.     

新致病基因在颅缝早闭Crouzon综合征中的初步机制研究

目的研究Rbp4(Retinol binding protein 4)、Gpc3(Glypican family of growth factor binding protein 3)、C1qtnf3(Collagenous repeat-containing sequence of 26 KDa protein)等新致病基因在颅缝早闭症中的发病机制,为疾病非手术治疗奠定理论基础。方法以Crouzon综合征Fgfr2cC342Y/+小鼠为实验模型,应用MicroCT和组织学染色,研究小鼠颅缝闭合模式;以Fgfr2cC342Y/+模型,RT-qPCR研究Rbp4、Gpc3、C1qtnf3等新致病基因的表达差异,初步探讨其在颅缝闭合过程中的调控作用;以体外培养的Fgfr2cC342Y/+小鼠颅缝细胞为模型,研究基因突变动物细胞增殖与代谢改变。结果获得Fgfr2cC342Y/+小鼠后额缝、冠状缝、人字缝、矢状缝等颅缝闭合模式,随颅骨发育、颅缝闭合,OC(Osteocalcin)、ALP(Alkalinephosphatase)表达增加,目的基因Rbp4、Gpc3、C1qtnf3表达下降,Msx2(Muscle segment homeobox gene 2)表达增加,杂合子与野生型小鼠之间均存在显著统计学差异,与前期人颅缝组织Microarray研究结果一致。Gpc1(Glypican family ofgrowth factor binding protein 1)、FliI(Flightless I)在颅缝闭合中的表达较恒定,野生型与杂合子之间未见明显统计学差异。体外培养Fgfr2cC342Y/+小鼠颅缝细胞,CellTiter96 MTS和Quant-iT Picogreen dsDNA细胞增殖与代谢分析结果显示,Fgfr2功能获得性突变可促进冠状缝细胞的增殖,从而导致成骨增加,颅缝早闭。结论 Fgfr2cC342Y/+模型新致病基因表达趋势与前期人颅缝组织Microarray研究结果一致,Rbp4、Gpc3、C1qtnf3可能在颅缝早闭中具重要调控作用。