幽门螺杆菌感染与胃癌的关系

目的 :探讨幽门螺杆菌 (简称 Hp)感染与胃癌的关系。方法 :43例胃癌患者的新鲜癌手术标本及血清标本、36例十二提肠溃疡患者 (对照组 )的胃窦粘膜组织及血清标本入本组研究。分别采用 PCR及血清学试验检测其 Hp感染状况 ,两项检测均为阳性者即确立为 Hp感染。结果 :(1) 4 3例胃癌中 ,Hp阳性 30例 ,阳性率 6 9.77% ;36例十二指肠溃疡中 ,Hp阳性 30例 ,阳性率 83.33% ,两组阳性率相比差异无显著性。Hp阳性患者中 ,胃癌及对照组 cag A基因阳性分别为 2 4例、2 5例 ,阳性率分别为 80 .0 0 %、83.33% ,两组阳性率相比差异无显著性。(2 ) 4 3例胃癌中 ,高中分化腺癌组 Hp及 cag A检出率分别为 6 2 .5 0 %及 70 .0 0 % ,低未分化癌组 Hp及 cag A检出率分别为 74.0 7%及 85 .0 0 % ,但两组 Hp及 cag A检出率统计学上均无显著性差异。结论 :(1) Hp感染及 cag A+ 菌株感染不是胃癌发生的唯一或必须因素。 (2 )胃癌的分化程度与 Hp及cag A+菌株感染无明显相关性。     

幽门螺旋杆菌感染与血型抗原相关性研究

目的通过观察幽门螺杆菌(Helicobacter pylori,Hp)在各血型患者中的分布情况,分析Hp感染与ABO血型、Lewis血型、分泌-非分泌表型的关系.方法收集幽门螺旋杆菌感染患者100例为感染组,100例健康的无偿献血者为对照组,分析两组患者的ABO血型系统、血型物质、Lewis血型系统的分布差异.结果 ABO血型分布比较:感染组O型血占56%(56/100),高于对照组的31%(31/100),感染组A型血占16%(16/100),低于对照组的33%(33/100).卡方检验结果显示:感染人群中O型血有较高发生率(56%),和普通人群中A型血(33%)之间具有显著性统计学意义(P0.05).ABO血型与幽门螺杆菌感染之间有相关性,O型人有较高感染倾向,而A型血则有较低感染倾向.Lewis表型分布比较:分析整个数据,感染组与对照组的表型分布基本一致,说明Lewis表型分布不受幽门螺杆菌感染的影响,感染组各表型与对照组比较差异无统计学意义.血型物质分布比较:分泌型个体分布在感染组和对照组之间比较差异无统计学意义.结论幽门螺杆菌感染与O型血有较强的关联,但与Lewis血型、分泌-非分泌表型无关.     

Mitochondrial genome variation and the origin of modern humans

The analysis of mitochondrial DNA (mtDNA) has been a potent tool in our understanding of human evolution, owing to characteristics such as high copy number, apparent lack of recombination, high substitution rate and maternal mode of inheritance. However, almost all studies of human evolution based on mtDNA sequencing have been confined to the control region, which constitutes less than 7% of the mitochondrial genome. These studies are complicated by the extreme variation in substitution rate between sites, and the consequence of parallel mutations causing difficulties in the estimation of genetic distance and making phylogenetic inferences questionable. Most comprehensive studies of the human mitochondrial molecule have been carried out through restriction-fragment length polymorphism analysis, providing data that are ill suited to estimations of mutation rate and therefore the timing of evolutionary events. Here, to improve the information obtained from the mitochondrial molecule for studies of human evolution, we describe the global mtDNA diversity in humans based on analyses of the complete mtDNA sequence of 53 humans of diverse origins. Our mtDNA data, in comparison with those of a parallel study of the Xq13.3 region in the same individuals, provide a concurrent view on human evolution with respect to the age of modern humans.     

An earlier origin for the Acheulian

The Acheulian is one of the first defined prehistoric techno-complexes and is characterized by shaped bifacial stone tools. It probably originated in Africa, spreading to Europe and Asia perhaps as early as ～1?million years (Myr) ago. The origin of the Acheulian is thought to have closely coincided with major changes in human brain evolution, allowing for further technological developments. Nonetheless, the emergence of the Acheulian remains unclear because well-dated sites older than 1.4?Myr ago are scarce. Here we report on the lithic assemblage and geological context for the Kokiselei 4 archaeological site from the Nachukui formation (West Turkana, Kenya) that bears characteristic early Acheulian tools and pushes the first appearance datum for this stone-age technology back to 1.76?Myr ago. Moreover, co-occurrence of Oldowan and Acheulian artefacts at the Kokiselei site complex indicates that the two technologies are not mutually exclusive time-successive components of an evolving cultural lineage, and suggests that the Acheulian was either imported from another location yet to be identified or originated from Oldowan hominins at this vicinity. In either case, the Acheulian did not accompany the first human dispersal from Africa despite being available at the time. This may indicate that multiple groups of hominins distinguished by separate stone-tool-making behaviours and dispersal strategies coexisted in Africa at 1.76?Myr ago.     

An association between actin and the major histocompatibility antigen H-2

P815 cells spontaneously shed material (exfoliate) in which actin is the major protein. The exfoliate also contains H-2. The association between actin and H-2 is stable even in the presence of detergent, indicating that protein-protein interactions exist between the actin and H-2. The exfoliate probably consists of highly purified microvilli.     

烛缸法分离培养及冷冻法保存幽门螺杆菌

目的研究幽门螺杆菌（H elicobacter py lori,H py lori）简易分离培养及保存方法,构建H py lori小型菌库。方法首先采用H py lori选择培养基,以烛缸法分离培养不同来源的标本,然后以革兰染色显微镜形态检查及生化试验鉴定为H py lori,最后把鉴定为H py lori的纯培养物,...     

An early evolutionary origin for the minor spliceosome

The minor spliceosome is a ribonucleoprotein complex that catalyses the removal of an atypical class of spliceosomal introns (U12-type) from eukaryotic messenger RNAs. It was first identified and characterized in animals, where it was found to contain several unique RNA constituents that share structural similarity with and seem to be functionally analogous to the small nuclear RNAs (snRNAs) contained in the major spliceosome. Subsequently, minor spliceosomal components and U12-type introns have been found in plants but not in fungi. Unlike that of the major spliceosome, which arose early in the eukaryotic lineage, the evolutionary history of the minor spliceosome is unclear because there is evidence of it in so few organisms. Here we report the identification of homologues of minor-spliceosome-specific proteins and snRNAs, and U12-type introns, in distantly related eukaryotic microbes (protists) and in a fungus (Rhizopus oryzae). Cumulatively, our results indicate that the minor spliceosome had an early origin: several of its characteristic constituents are present in representative organisms from all eukaryotic supergroups for which there is any substantial genome sequence information. In addition, our results reveal marked evolutionary conservation of functionally important sequence elements contained within U12-type introns and snRNAs.     

Zoological origin of gonadotropin subunits and association kinetics

Mammalian luteinizing hormone (LH) is an association of two dissimilar subunits, alpha and beta. In vitro studies, mainly using difference spectrophotometry, had shown that this phenomenon was slow, especially at low temperatures. If the situation was the same in poikiloterms, it would probably make gonadotropin (GTH) synthesis difficult for these animals in a cold environment. We have found that the formation of a teleost gonadotropin is in fact strikingly more rapid and less thermodependent than formation of mammalian LH. Also, studies with a fish-mammal hybrid molecule have allowed us to estimate the respective influence of the alpha and beta subunits in determining these differences.     

幽门螺杆菌重组VacA蛋白的表达、纯化和鉴定

建立从幽门螺杆菌空泡毒素A(VacA)原核表达系统pET32a-vacA-E.coliBL21DE3中,表达、纯化和鉴定重组空泡毒素A(rVacA)蛋白的方法.采用不同浓度的IPTG(0.1、0.5和1.0 mmol.L-1)诱导原核表达系统表达rVacA,10%SDS-PAGE检测表达产量,Ni-NTA亲和层析法纯化rVacA,采用HPLC检测其纯度,Western-blotting进行免疫学鉴定.从已构建的VacA原核表达系统中成功表达和纯化了rVacA蛋白,产量约占细菌总蛋白的28.4%,纯度为82.3%.为后续进一步研究该蛋白的生物活性和相关检测试剂盒奠定基础.     

一种利用混合模型研究基因与疾病问关联的方法

给出了将多位点基因型信息作为混杂因子的协变量,利用混合模型讨论在病例一对照研究中,当被研究群体中存在着分层现象时,被研究基因与疾病之间关联的一种新的方法.在子群体内部满足Hardy-Weinberg平衡时,此方法充分地利用已知信息,用基因标识物将群体分层,并估计出被研究基因与疾病之间的关联性,同时还考虑了多位点基因型数据有缺失的情况.     

一种利用混合模型研究基因与疾病间关联的方法

给出了将多位点基因型信息作为混杂因子的协变量,利用混合模型讨论在病例一对照研究中,当被研究群体中存在着分层现象时,被研究基因与疾病之间关联的一种新的方法．在子群体内部满足Hardy-Weinberg平衡时,此方法充分地利用已知信息,用基因标识物将群体分层,并估计出被研究基因与疾病之间的关联性,同时还考虑了多位点基因型数据有缺失的情况．     

Positive selection of a gene family during the emergence of humans and African apes

Gene duplication followed by adaptive evolution is one of the primary forces for the emergence of new gene function. Here we describe the recent proliferation, transposition and selection of a 20-kilobase (kb) duplicated segment throughout 15 Mb of the short arm of human chromosome 16. The dispersal of this segment was accompanied by considerable variation in chromosomal-map location and copy number among hominoid species. In humans, we identified a gene family (morpheus) within the duplicated segment. Comparison of putative protein-encoding exons revealed the most extreme case of positive selection among hominoids. The major episode of enhanced amino-acid replacement occurred after the separation of human and great-ape lineages from the orangutan. Positive selection continued to alter amino-acid composition after the divergence of human and chimpanzee lineages. The rapidity and bias for amino-acid-altering nucleotide changes suggest adaptive evolution of the morpheus gene family during the emergence of humans and African apes. Moreover, some genes emerge and evolve very rapidly, generating copies that bear little similarity to their ancestral precursors. Consequently, a small fraction of human genes may not possess discernible orthologues within the genomes of model organisms.     

抗幽门螺杆菌便餐粉配方优化及其体外抑菌研究

为制备抗幽门螺杆菌便餐粉,将实验室制备的高免蛋液(由Ure B、BabA2和Fla A免疫产蛋鸡后制备而成,含Ure B-BabA2-FlaA-IgY)通过喷雾冷冻干燥技术获得高免蛋粉。在原有配方的基础上,通过单因素实验研究木糖醇添加量、麦芽糊精添加量和高免蛋粉添加量对便餐粉品质指标(休止角、堆积密度、结块率、流动性、挂壁)的影响。在单因素实验基础上,以口感评分为指标,通过正交试验设计获得便餐粉最佳组合。通过间接Elisa法分析便餐粉的效价稳定性,将便餐粉与幽门螺杆菌菌液共培养,测定OD_(600)值分析其抑菌效果。结果表明当麦芽糊精添加量为20%、木糖醇添加量为10%、高免蛋粉添加量为15%时,便餐粉的品质最佳,37℃条件下,便餐粉效价在4个月内无显著性变化,60 mg/m L的便餐粉可有效抑制幽门螺杆菌的生长。成功研制出抗幽门螺杆菌便餐粉。     

一种关联规则Apriori算法的改进

关联规则Apriori算法自提出以来,有很多的改进算法,但大多是在改变最小支持度的大小,这样虽可提高Apriori算法的速度,但会漏掉一些有用的项集.本文结合以上问题,用一种科学的方法求出最小支持度,并在提取频繁项集的过程中动态地改变最小支持度的值,有效地解决了以上问题,提高了Apriori算法的效率.     

An origin in the local Universe for some short gamma-ray bursts

Gamma-ray bursts (GRBs) divide into two classes: 'long', which typically have initial durations of T90 > 2 s, and 'short', with durations of T90 < 2 s (where T90 is the time to detect 90% of the observed fluence). Long bursts, which on average have softer gamma-ray spectra, are known to be associated with stellar core-collapse events-in some cases simultaneously producing powerful type Ic supernovae. In contrast, the origin of short bursts has remained mysterious until recently. A subsecond intense 'spike' of gamma-rays during a giant flare from the Galactic soft gamma-ray repeater, SGR 1806-20, reopened an old debate over whether some short GRBs could be similar events seen in galaxies out to approximately 70 Mpc (refs 6-10; redshift z approximately 0.016). Shortly after that, localizations of a few short GRBs (with optical afterglows detected in two cases) have shown an apparent association with a variety of host galaxies at moderate redshifts. Here we report a correlation between the locations of previously observed short bursts and the positions of galaxies in the local Universe, indicating that between 10 and 25 per cent of short GRBs originate at low redshifts (z < 0.025).     

一种大规模、快速的幽门螺杆菌脲酶分离纯化方法研究

幽门螺杆菌定植于人胃黏膜并产生大量的脲酶,报道一种大规模、快速的脲酶纯化方法.脲酶用去离子水振荡及冻融法抽提,采用Q Sepharose FF阴离子交换层析,Phenyl Sepharose HP疏水相互作用和SOURCE30S阳离子交换层析等方法纯化得到脲酶,通过酚红脲酶试剂检测酶活.总蛋白回收率为2.58%,纯化后脲酶纯度大于95%,SDS-PAGE电泳显示脲酶是由相对分子质量66 000的A亚基和30 000的B亚基组成.     

An exceptional adult-clutch-embryo association and its implications for dinosaur reproduction

Dinosaur egg clutches represent remarkable specimens in being both body fossils (the anatomical remains of an ancient animal) as well as a trace fossil (the dir...     

挖掘关联规则中Apriori算法的一种改进

算法减少连接次数以及扫描数据库的次数从而缩短数据库扫描时间,利用项集有序性改进判断是否进行连接的策略,并利用标志位变化逐步消除无用事务,从而实现了事务压缩和项目压缩, 同时减少了判断时间。实验结果表明,经过优化了的Apriori算法在运行效率上有一定的提高。