儿童再发性腹痛中幽门螺杆菌不同检测方法

目的 评价幽门螺杆菌（H.pylori）的不同检测方法及H.pylori感染在儿童再发性腹痛（RAP）诊断中的应用.方法 对在我院诊治的儿童RAP 72例,分为学龄期组24例,少年组48例,同时进行细菌培养、快速尿素酶试验、病理组织学检查、血清学H.pylori抗体检测和粪便H.pylori抗原（HpSA）检测.将前3项检查中2项阳性或细菌培养一项阳性作为诊断H.pylori感染的金标准.结果 金标准诊断H.pylori感染,阳性占37例,阴性占35例,总阳性率为51.4%;学龄期儿童组H.pylori检出阳性率为37.5%,少年组H.pylori检出阳性率为58.3%,两组比较差异有显著性（P＜0.01）;比较6种不同检测方法的敏感性、特异性、准确性,经x2检验,差异均无显著性（P＞0.10）.结论 H.pylori感染与儿童RAP之间存在一定的联系,少年组H.pylori感染率高于学龄期儿童组,而粪便HpSA检测有较高的敏感性和特异性,是一种简便可靠,非侵入性的诊断H.pylori感染的方法,尤其适合儿童.     

儿童幽门螺杆菌及CagA阳性感染的临床研究

目的探讨非侵入性检查方法对儿童幽门螺杆菌(H.pylori)的诊断及治疗价值。方法对2004年10月至2005年12月在梅县人民医院门诊及住院154例慢性反复腹痛患儿进行粪便幽门螺杆菌抗原(HPSA)血清(H.pylori)抗体(HP-Ab)及产细胞毒素相关蛋白(CagA)、H.pylori检查测验,并对CagA阳性患者于短程三联抗H.pylori干预治疗。结果154例患儿中H.pylori阳性33.8%(52/154),CagA阳性61.5%(32/52)。H.pylori阳性及CagA阳性者以上腹疼痛,恶心呕吐多于H.pylori阴性患者,但它们之间差异无显著性,P>0.05;H.pylori阳性及CagA阳性与H.pylori阴性者病程上差异无显著性,P>0.05。对CagA阳性干预治疗后4周临床症状消失达90.6%(29/32),HPSA转阴率为87.5(28/32),结论H.pylori阳性及CagA阳性与否不能以临床表现作为判断标准,H.pylori及CagA的检测可作为对儿童特别是幼儿诊断H.pylori感染及治疗后复查,简便,患儿易接受,特别适用基层的一种非侵入性检测方法。     

慢性腹痛患儿C~(13)-尿素呼气试验与胃镜检查的临床意义

目的了解慢性腹痛患儿幽门螺杆菌(H.pylori)的感染状态及幽门螺杆菌感染患儿内镜下表现的特点。方法应用C13尿素呼气试验,对905例以慢性腹痛为主要症状的患儿进行检测,对C13呼气试验阳性者进行电子胃镜检查。结果905例慢性腹痛患儿中H.pylori呈阳性185例(20.44%),随年龄增长,其H.pylori阳性率升高,学年组已达高峰。对H.pylori阳性者进行胃镜检查结果显示十二指肠隆起病变47例占25.40%,结节性胃炎41例占22.1%,慢性浅表性`胃炎38例占20.5%,结节性胃炎伴十二指肠隆起病变23例占12.43%,十二指肠球部溃疡23例占12.4%。胃溃疡7例,占3.7%(其中包括1例复合性溃疡),结节性胃炎伴十二指肠炎6例,占3.2%。结论H.pylori感染为小儿慢性腹痛的主要原因之一,也是导致慢性胃炎及消化性溃疡的主要原因之一。C13尿素呼气试验方便,快速,无痛苦,无放射性,是一较好的H.pylori检测方法;对既有消化道症状同时C13呼气试验阳性者进行胃镜检查能够协助临床诊断及治疗。     

改良幽门螺杆菌抗原检测试剂盒 检测粪便幽门螺杆菌抗原的临床评价

目的评估改良幽门螺杆菌抗原检测试剂盒检测粪便幽门螺杆菌抗原(Helicobacter pylori stool antigen,HpSA)的准确性以及临床应用价值。方法采用随机、双盲、双验证和与~(13) C呼气试验(~(13) C-UBT)对比的方法,对门诊175例接受~(13) C-UBT检测的患者,采用最新研制出的一种改良幽门螺杆菌抗原检测试剂盒(胶体金法)检测粪便幽门螺杆菌抗原,以~(13) C-UBT检测结果为诊断H.pylori感染的"金标准",并将两者进行对比研究,所有检测结果均拍照存档,采用随机、双盲和双验证法,以期客观真实地评价改良幽门螺杆菌抗原检测试剂盒检测粪便幽门螺杆菌的效果。结果改良幽门螺杆菌抗原检测试剂盒检测HpSA敏感度为90.48%,特异度为90.00%,Youden指数为80.48%,Kappa值为0.799;HpSA检测ROC曲线下面积为0.902±0.027,与完全无诊断价值的机会线下面积0.50相比,差异有统计学意义(P=0.000);Spearman相关系数r=0.800,P=0.000。结论改良幽门螺杆菌抗原检测试剂盒能准确检测H.pylori感染,其操作简便,可作为非侵入性诊断H.pylori感染筛查以及流行病调查的一种方法,将来有望成为患者家庭自查幽门螺杆菌的一种方法。     

幽门螺杆菌对胃上皮细胞间隙连接超微结构的影响(英文)

通过实验和临床观察幽门螺杆菌（Helicobacter pylori）对胃上皮细胞间隙连接超微结构的影响,从细胞间隙连接角度探讨H.pylori致癌机制.将不同H.pylori菌株与BGC-823细胞共培养24h或48h,用原位固定与原位包埋法透射电镜观察细胞间隙连接超微结构变化.对70例胃癌患者,用快速尿素酶试验、碱性品红染色和14C尿素呼气实验检测H.pylori,PCR法检测H.pyloriCagA基因,及透射电镜观察胃上皮细胞间隙连接超微结构变化.结果显示,未加H.pylori组BGC-823细胞可见较多细胞连接及连接复合体,加H.pylori各组细胞的连接数、单位周长连接数与单位周长连接长度均小于未加H.pylori组,而细胞间隙最小宽度大于未加H.pylori组（P〈0.001或P〈0.005）,且CagA＋的NCTCJ99组、临床株GC01组和NCTC11639组细胞连接数、单位周长连接数均小于CagA-的NCTC12908组（P〈0.001或P〈0.05）,NCTCJ99组与临床株GC01组细胞单位周长连接长度短于NCTC12908组（P〈0.001）.胃癌患者H.pylori感染组细胞连接数、单位周长连接数与单位周长连接长度均小于无H.pylori感染组,细胞间隙最小宽度大于无H.pylori感染组（P〈0.001）,且CagA＋H.pylori感染者细胞连接数、单位周长连接数与单位周长连接长度均小于CagA-H.pylori感染者,细胞间隙最小宽度大于CagA-H.pylori感染者.上述结果表明,胃上皮细胞间隙连接改变与H.pylori感染,特别是CagA＋H.pylori感染有关.     

幽门螺杆菌检测技术研究进展及展望

幽门螺杆菌是(Helicobacter pylori,H. pylori)是导致人类多种胃肠疾病的主要病因,通过多种毒力因子导致各种疾病的发生和发展。鉴于目前幽门螺杆菌缺少商业化疫苗且多重耐药性问题日益严重,临床上对其根除效果不佳,因此,精准的检测技术是预防幽门螺杆菌感染的关键,也是评估感染后治疗效果的重要手段。幽门螺杆菌的检测方法主要包括尿素呼气试验、快速尿素酶试验、粪便抗原检测、血清学检查、内镜检查、组织学病理检查、聚合酶链式反应及细菌培养,每种方法在临床上皆存在优点与局限性。目前,对于幽门螺杆菌检测的“金标准”尚无统一定论,因此本文重点综述当前应用的幽门螺杆菌检测技术,分析其优点和局限性,并指明精准、快速且便捷的检测技术在流行病学调查等方面具备的优势,旨在为临床和研究提供科学的参考依据。     

胃癌发生不同阶段临床和胃镜表现及与幽门螺杆菌感染的关系

目的观察慢性浅表性胃炎(CSG)→萎缩性胃炎(CAG)→肠上皮化生(IM)→非典型增生(DYS)→胃癌(GC)五个不同阶段临床和胃镜表现及其与幽门螺杆菌(H.pylori)感染的关系。方法对经胃镜及病理证实的上述GC发生五个不同阶段的患者各50例,详细询问其临床症状,记录胃镜下表现,并用快速尿素酶试验(RUT)、14C尿素呼气试验(14C-UBT)、组织学检查及H.pylori培养等方法检测H.pylori感染情况。结果 (1)CSG和GC的临床表现分别以上腹胀和早饱、体重减轻为主,其他阶段均以上腹痛为主;(2)CSG、CAG和GC的胃镜下表现依次以疣状隆起及糜烂、黏膜变薄及血管显露、巨大溃疡及出血为多见,而IM和DYS均以直径小于2 cm的溃疡为多见(P0.05);(3)H.pylori感染:从CSG→GC不同阶段,H.pylori感染率依次降低(分别为80%、78%、62%、56%和36%,P0.05);临床表现中上腹痛及纳差H.pylori感染率高,早饱H.pylori感染率低(P0.05);不同胃镜下表现中溃疡H.pylori感染率最高(P0.05)。结论体重减轻可作为胃癌警示信号,胃镜下巨大溃疡及出血以GC多见;H.pylori感染率与GC发生阶段呈负相关,临床表现为上腹痛、纳差,及胃镜下溃疡患者H.pylori感染率高。     

基于卷积神经网络的侵入性酿酒酵母感染疾病的检测方法

酿酒酵母(Saccharomyces cerevisiae)是常用于烘焙和酿造行业的发酵菌种,也作为益生菌用于预防和治疗各种腹泻及其相关疾病.然而,近二十年来,由于摄入酿酒酵母产生的侵入性酿酒酵母感染的病例一直在不断增加,特别是在老年人、免疫功能低下和危重患者群体中.此外,目前临床上所用酿酒酵母侵入性感染疾病的诊断方法耗时较长,而容易错过最佳的诊断时间和难以实现早期预防.本文提出了一种基于卷积神经网络的目标检测的方法用于对血液中的酿酒酵母细胞进行检测和识别,以达到侵入性酿酒酵母疾病诊断的目的.该方法是基于以ResNet-50网络结构作为特征提取网络构建的SSD算法.以实际采集的血液和酿酒酵母细胞混合液的样本图像作为算法的训练和测试数据,实验结果表明该方法的识别准确率可达到97.70%,检测时间为0.31 s.并且通过与相似的其他3种卷积神经网络算法的测试对比,结果表明该算法识别准确率也有着明显的优势.该论文通过实验验证了,基于卷积神经网络的目标检测方法有望作为侵入性酿酒酵母感染疾病检测和诊断的一种新方法;且该方法检测准确率高和时间短的优势有望实现侵入性酿酒酵母感染疾病的早期预防和及时诊...     

幽门螺杆菌感染诊断方法的比较

目的:考核各种H.pylori感染诊断方法,试图证明分离培养仍是细菌性感染诊断的最可靠方法.方法:315例胃十二指肠疾病患者同时进行胃活检组织分离培养,病理切片找菌,快速脲酶试验,14CO2呼气试验检查,比较它们之间的检出率差异.结果:四种方法各自的总检出率差异无显著性.以分离培养为金标准,其他方法的误诊误治率可达12.06%～22.22%.各种诊断方法对H.pylori感染的实际检出率差异存在着显著性.结论:本研究提示,分离培养应为H.pylori感染临床诊断的金标准.     

白光胃镜下胃体黏膜形态与幽门螺杆菌感染的关系及其病理特征

目的探讨白光胃镜常规检查时根据不同的胃体黏膜形态判断幽门螺杆菌(H.pylori)感染的准确性及其病理表现,了解胃体黏膜形态变化的临床意义。方法选择2017年3月至2018年9月于本院行胃镜检查的520例患者为研究对象,对患者胃体和胃窦同时进行组织病理学和快速尿素酶检查及白光胃镜检查,根据白光胃镜检查结果分为胃体黏膜病变组(232例)和无胃体黏膜病变组(288例),分析胃镜下不同黏膜组织病变与H.pylori的感染情况,采用四格表分析白光胃镜检测对H.pylori感染的诊断价值。结果与无胃体黏膜病变组比较,胃体黏膜病变组患者H.pylori感染率显著升高,同时胃体黏膜黏液分泌增多、胃体黏膜广泛充血、胃体皱襞肥大、黏膜水肿、胃体黏膜"龟纹样"改变、胃体(单发或多发)息肉、胃体可见RAC。不同胃体黏膜病变患者H.pylori感染率差异有统计学意义(χ~2=62.711,P0.001)。胃体黏膜病变患者H.pylori感染率与十二指肠炎、十二指肠溃疡无关(均P0.05),与反流性食管炎、胃溃疡、胃窦糜烂有关(χ~2=7.087、6.230、17.934,P=0.008、0.013、0.001)。白光胃镜诊断H.pylori感染的灵敏度为71.43%,特异度为90.27%,准确度为79.62%,阳性预测值为90.52%,阴性预测值为70.83%。结论白光胃镜下胃体黏膜形态与H.pylori感染率及与炎症、肠化生、黏膜萎缩、非典型增生、反流性食管炎、胃溃疡、胃窦糜烂有关,白光胃镜检查可能对H.pylori感染有一定诊断价值。白光胃镜下较常见且易识别的胃体黏膜充血、水肿、"龟纹样"改变、胃体可见RAC等可能成为白光胃镜预测H.pylori感染的特异性表现。     

Goodness-of-Fit Testing for the Logistic Regression Model when the Estimated Probabilities are Small

The distribution of the Hosmer-Lemeshow chi-square type goodness-of-fit tests (?_g, ?_g) for the logistic regression model are examined via simulations designed to examine their behavior when most of the estimated probabilities are small or are expected to fall in a few deciles. The results of the simulations show statistic ?_g should be used when the two outcome groups (y = 0, 1) are not well separated, Δ≤2, where Δ² is the Mahalanobis distance. Statistic ?_g should be used when Δ ≥ 8. Either statistic may be used when 2 ≦ Δ ≦ 8. All tests should be used with caution when the proportion in the sample with y = 1 is less than 0.1.     

A Primer to Molecular Phylogenetic Analysis in Plants

Reconstructing a tree of life by inferring evolutionary history is an important focus of evolutionary biology. Phylogenetic reconstructions also provide useful information for a range of scientific disciplines such as botany, zoology, phylogeography, archaeology and biological anthropology. Until the development of protein and DNA sequencing techniques in the 1960s and 1970s, phylogenetic reconstructions were based on fossil records and comparative morphological/physiological analyses. Since then, progress in molecular phylogenetics has compensated for some of the shortcomings of phenotype-based comparisons. Comparisons at the molecular level increase the accuracy of phylogenetic inference because there is no environmental influence on DNA/peptide sequences and evaluation of sequence similarity is not subjective. While the number of morphological/physiological characters that are sufficiently conserved for phylogenetic inference is limited, molecular data provide a large number of datapoints and enable comparisons from diverse taxa. Over the last 20 years, developments in molecular phylogenetics have greatly contributed to our understanding of plant evolutionary relationships. Regions in the plant nuclear and organellar genomes that are optimal for phylogenetic inference have been determined and recent advances in DNA sequencing techniques have enabled comparisons at the whole genome level. Sequences from the nuclear and organellar genomes of thousands of plant species are readily available in public databases, enabling researchers without access to molecular biology tools to investigate phylogenetic relationships by sequence comparisons using the appropriate nucleotide substitution models and tree building algorithms. In the present review, the statistical models and algorithms used to reconstruct phylogenetic trees are introduced and advances in the exploration and utilization of plant genomes for molecular phylogenetic analyses are discussed.     

喷气燃料中污染微生物检测方法概况

微生物污染不仅降解喷气燃料,还严重威胁储存和飞行安全.喷气燃料中污染微生物的检测是有效治理微生物污染的前提.基于此,本文将喷气燃料中污染微生物检测方法分为传统法、分析生物学法以及分子生物学方法,并对三种方法优缺点进行了详细介绍.最后对喷气燃料中污染微生物检测方法进行了展望.     

测定糖尿病患者血清LDL-C水平的方法学比较

目的：比较不同方法检测糖尿病患者血清LDL-C水平,为临床诊疗提供准确可行的检验方法。方法：采用沉淀法、匀相法、电泳法及超速离心法对233例糖尿病患者和102例健康人群的血清LDL-C水平进行测定,比较各方法之间的相关性,同时分析导致结果差异的因素。结果：四种方法检测健康人群LDL-C水平,结果间无统计学差异（P〉0.05）;糖尿病组,当TG≤2.26mmol/L时,四种方法检测LDL-C结果间相关性良好。高胆红素、血红蛋白、高TG及乳糜等干扰因素存在时,与其他方法相比,电泳法和超速离心法检测血清LDL-C结果受影响较小（P〉0.05）。结论：超速离心法虽耗时、价格贵,但仍为检测LDL-C的经典方法,电泳法受高胆红素、血红蛋白、高三酰甘油等干扰因素的影响相对较小,适用于糖尿病合并高血脂患者血清LDL-C水平检测。     

测定糖尿病患者血清LDL-C 水平的方法学比较

目的:比较不同方法检测糖尿病患者血清LDL-C水平,为临床诊疗提供准确可行的检验方法。方法:采用沉淀法、匀相法、电泳法及超速离心法对233例糖尿病患者和102例健康人群的血清LDL-C水平进行测定,比较各方法之间的相关性,同时分析导致结果差异的因素。结果:四种方法检测健康人群LDL-C水平,结果间无统计学差异(P>0.05);糖尿病组,当TG≤2.26mmol/L时,四种方法检测LDL-C结果间相关性良好。高胆红素、血红蛋白、高TG及乳糜等干扰因素存在时,与其他方法相比,电泳法和超速离心法检测血清LDL-C结果受影响较小(P>0.05)。结论:超速离心法虽耗时、价格贵,但仍为检测LDL-C的经典方法,电泳法受高胆红素、血红蛋白、高三酰甘油等干扰因素的影响相对较小,适用于糖尿病合并高血脂患者血清LDL-C水平检测。     

Microbial Biomass Estimation

ABSTRACT

The development of a fully automated on-line monitoring and control system is very important in bioprocesses. One of the most important parameters in these processes is biomass. This review discusses different methods for biomass quantification. A general definition of biomass and biovolume are presented. Interesting concepts about active but not culturable cells considerations are included as well as concepts that must be taken into account when selecting biomass quantification technology. Chemical methods have had few applications in biomass measurement to date; however, bioluminescence can selectively enumerate viable cells. Photometric methods including fluorescence and scattered light measurements are presented. Reference methods including dry and wet weight, viable counts and direct counts are discussed, as well as the physical methods of flow cytometry, impedancimetric and dielectric techniques.     

PCR detection of pirimicarb resistance in Australian field isolates of Aphis gossypii Glover (Aphididae: Hemiptera)

Aphis gossypii Glover (cotton aphid) is a major secondary pest of Australian cotton that readily develops resistance to the carbamate insecticide pirimicarb (Pirimor®) and to organophosphates generally. To test the pirimicarb resistance status of Australian strains of A . gossypii , a polymerase chain reaction (PCR) assay followed by restriction enzyme assay (REA) was designed to identify the Ace I polymorphism S431F known to be responsible for resistance. The method was tested against reference and 33 field strains collected over two consecutive seasons. Both methods confirmed pirimicarb resistance in two field strains, one from each cotton season, giving credence to the molecular technique described. The PCR assay proved specific for the Ace I gene. This PCR REA assay has the potential to replace bioassay for the routine pirimicarb resistance monitoring in A . gossypii. With the molecular assay providing results in 48 h, compared with 4–8 weeks for bioassay, such an assay could be used before insecticide control.     

A window on cyclitols: Characterization and analytics of inositols

Cyclitols are cycloalkanes with one hydroxyl group on each of three or more ring atoms, also called cycloalkane polyols or sugar alcohol which attract attention since they have numerous pharmaceutical properties and are widespread in the plants. Inositols are important cyclitols, which constitute a group of naturally occurring polyhydric alcohols and some isomers of this group can be commonly found in most plants, provided adequate methods of detection are employed. This review presents plant containing cyclitols, with emphasis put on their pharmaceutical properties. The text focuses on sample preparation, extraction and purification and on analysis of cyclitols in plants. In addition, it addresses the application of different methodologies utilized in the analysis of cyclitol compounds in plant.     

基于β-微管蛋白基因部分序列探讨灵芝属菌株的亲缘关系

PCR分别扩增了38个灵芝属菌株的β-微管蛋白基因片段,并对PCR产物进行序列测定,得到419bp的一段核苷酸系列.根据MEGA 2.1软件中的neighbour-joining methods对上述序列进行聚类分析,结果所有供试菌株被分成9个聚类组.中国栽培灵芝菌株分布于6个聚类组,其中树舌亚属、紫芝组的菌株各自聚成一组,灵芝组的菌株分成四组,但大部分灵芝组菌株均聚于同一组, 这表明树舌亚属、紫芝组和灵芝组间的遗传差异较大,灵芝组内虽然存在着一定的遗传差异,但总体上亲缘关系比较近,遗传多样性并不丰富.同时,序列分析的结果显示,β-tubulin基因序列在第三位密码子和内含子部位有高的碱基替换率,这些变异提供了丰富的系统发育信息,提示β-tubulin基因适合于灵芝属菌株的亲缘关系研究.     

Rapidly converging numerical algorithms for models of population dynamics

We propose algorithms for the approximation of the age distributions of populations modeled by the McKendrick-von Foerster and the Gurtin-MacCamy systems both in one- and two-sex versions. For the one-sex model methods of second and fourth order are proposed. For the two-sex model a second order method is described. In each case the convergence is demonstrated. Several numerical examples are given.