错配修复蛋白hMSH2、hMLH1在涎腺粘液表皮样癌中的表达

目的:探讨人类错配修复基因2 the human mutS homolog 2(hMSH2)人类错配修复基因1human mutL homolog 1(hMLH1)在涎腺粘液表皮样癌(salivary gland mucoepidermoid carcinoma-SMEC)表达水平及临床病理意义。重点研究人类错配修复基因2和人类错配修复基因1与目标肿瘤发生的相关性。方法:采用HE染色方法筛选共计47例典型病例,采用免疫组织化学染色分析37例SMEC、10例正常组织涎腺中hMSH2、hMLH1的表达水平,结合计算机辅助高清晰图像分析处理技术做出综合评价。结果:hMLH1的表达与SMEC分化呈负相关(P0.05);hMLH1的低表达或表达缺失在低分化的SMEC中较普遍,在中分化和高分化中表达逐步增强;hMSH2的表达与SMEC分化不相关(P0.05)。结论:hMSH2、hMLH1异常表达与涎腺黏液表皮样的发生、演进存在相关性,以hMLH1、hMSH2为切入点为涎腺黏液表皮样癌治疗与预防提供参考依据。     

食管鳞状细胞癌癌组织中hMLH1、hMSH2的表达及其意义

目的:探讨错配修复基因hMSH2、hMLH1在食管鳞癌组织中的表达及其临床意义。方法:采用sP免疫组化的方法检测144例食管鳞癌手术切除标本、30例正常粘膜组织中hMSH2、hMLH1表达情况,并与临床病理参数作相关分析。结果:食管鳞癌组织hMSH2、hMLH1基因阳性表达明显下降,与正常食道粘膜相比相差显著(P<0.01),hMSH2、hMLH1表达缺失与年龄、性别、肿瘤大小、淋巴结转移、浸润深度无显著相关,与肿瘤的分化程度有关(P<0.01)。结论:提示hMLH1和hMSH2基因突变所致的蛋白表达异常缺失与食管鳞状细胞癌发生有关,可能为一种早期事件。     

口腔鳞状细胞癌中hMSH2、PCNA和p53的表达及意义

目的:探讨hMSH2、PCNA和p53在OSCC中的表达及可能存在的临床意义.方法:运用免疫组织化学S-P法对56例OSCC组织中hMSH2、PCNA和p53的表达进行检测.结果:(1)3种基因产物在OSCC中的阳性率均高于正常口腔黏膜,中-低分化癌的阳性率高于高分化癌,有淋巴结转移的阳性率高于无淋巴结转移.(2)hMSH2与PCNA、p53,p53与PCNA的表达均呈正相关.(3)5年生存率与hMSH2蛋白表达和淋巴结转移有关.结论:hMSH2、PCNA和p53的异常表达及其相互之间的调节可能与OSCC的发生发展有关.     

四种错配修复基因蛋白在结直肠癌中的表达及临床意义

目的:分析hMLH1、hMSH2、hMSH6和hPMS2四种错配修复基因蛋白在结直肠癌中的表达及其临床意义。方法:随机选取2013年1月至2015年12月广州医科大学附属第三医院结直肠癌患者标本177例,采用免疫组织化学法检测hMLH1、hMSH2、hMSH6和hPMS2蛋白的表达情况,并分析蛋白表达与临床参数间关系。结果:177例结直肠癌组织中,hMLH1蛋白的缺失率为6.2%(11/177),hMSH2蛋白的缺失率为4.0%(7/177),hMSH6蛋白的缺失率为1.7%(3/177),hPMS2蛋白的缺失率为8.0%(14/177),四者之和占所有结直肠癌病例的19.8%(35/177)。四种错配修复基因蛋白表达缺失均与肿瘤发生部位有关(P0.05),另外,hMLH1及hPMS2蛋白的表达缺失还与肿瘤分化程度相关(P0.05),hMSH6蛋白的表达缺失还与肿瘤浸润深度相关(P0.05);而缺失均与年龄、性别、淋巴结转移和远处转移无关(P0.05)。结论:错配修复蛋白的表达在部分结直肠癌组织中出现缺失现象,且与肿瘤部位及分化程度密切相关。hMLH1、hMSH2、hMSH6和hPMS2四种基因的突变,为临床判断预后及拟定治疗方案提供一个有参考价值的依据。     

蕈样肉芽肿和湿疹中p53, Cox-2 的表达分析

目的:探讨蕈样肉芽肿、湿疹、正常皮肤中p53、Cox-2蛋白的表达差异性及其临床意义。方法:运用免疫组织化学法检测30例蕈样肉芽肿、20例湿疹及15例正常人皮肤组织中p53、Cox-2蛋白的表达情况。结果:蕈样肉芽肿表皮中及真皮中p53、Cox-2的阳性表达率显著高于湿疹及正常皮肤,差异均有统计学意义(P0.05)。各时期蕈样肉芽肿表皮、真皮中p53、Cox-2的表达比较差异均无统计学意义(P0.05)。结论:p53、Cox-2在蕈样肉芽肿和湿疹、正常皮肤的表达有显著差异,提示p53和Cox-2的表达异常在蕈样肉芽肿的发生中起着重要作用,p53、Cox-2可能作为鉴别诊断MF、皮肤炎症性疾病有价值的参考指标。     

hMSH6 和P53在散发性结肠癌中的表达及意义

目的:研究人类mut-s同系物6(hMSH6)和P53蛋白在散发性结肠癌(SCC)中的表达及与SCC病理特征的关系。方法:采用免疫组化Max-Vision二步法检测48例SCC癌组织、距癌灶3~9 cm的癌旁组织及≥10 cm的结肠组织以及45例正常结肠组织中hMSH6、P53的表达情况。结果:癌组织、距癌灶3~9 cm的癌旁组织中,hMSH6的阳性表达率低于距癌灶≥10 cm结肠组织及正常结肠组织,P53的阳性表达率高于距癌灶≥10 cm结肠组织及正常结肠组织,差异比较有统计学意义(P0.05);hMSH6阳性表达与癌灶部位及浸润深度有关(P0.05);P53阳性表达与组织学分级有关(P0.05);hMSH6与P53阳性表达呈负相关(r=-0.403,P0.05)。结论:hMSH6、P53的异常表达参与了SCC发生及发展的过程,hMSH6、P53可作为评价SCC生物学行为的指标。     

抑癌基因p53 在肝癌组织中的异常表达及临床意义

目的:探讨抑癌基因p53在肝癌组织中表达及临床意义,为肝癌的治疗提供新的思路。方法:回顾性分析了2006年1月～2009年8月收治的40例肝癌患者的临床资料,采用免疫组织化学法测定肝癌组织、癌旁组织和正常组织中抑癌基因p53的表达,并分析不同肿瘤分化程度患者p53的表达。结果:p53阳性表达率在在肝癌组、癌旁组分别为47.5%和2.5%,在正常组未检测到p53阳性表达,三组之间比较有显著性差异(x2=6.515,P=0.024);高分化癌P53蛋白阳性表达率低,中低分化癌P53蛋白阳性表达率高,组比较均有显著性差异(P<0.05),中、低分化组之间比较差异无统计学意义(P>0.05)。结论:在肝癌组织中存在p53基因的高表达,其阳性表达与肿瘤分化程度有关。     

子宫内膜异位症中hMLH1、hMSH2基因启动子区的甲基化研究

目的：探讨错配修复基因1（hMLH1）、错配修复基因2（hMSH2）启动子区甲基化与子宫内膜异位症的关系。方法：采用甲基化特异性PCR方法检测23例子宫内膜异位症组织和20例正常子宫内膜中hMLH1、hMSH2基因启动子区的甲基化状态。结果：hMLH1基因在子宫内膜异位症中的甲基化率为39％（9/23）,在正常子宫内膜组织中的甲基化率为5％（1／20）,两者比较,差异有统计学意义（P〈0．05）;hMSH2基因在子宫内膜异位症中的甲基化率为8％（2／23）,在正常子宫内膜组织中的甲基化率为5％（1／20）,两者比较,无明显差异（P〉0．05）。结论：hMLH1基因启动子区甲基化可能与子宫内膜异位症发病有关;hMSH2基因启动子区甲基化与子宫内膜异位症之间不存在显著联系。     

蛋白激酶CK2-β及其相关的p53在涎腺腺样囊性癌中的表达及意义

目的　通过对蛋白激酶CK2 β (proteinkinaseCK2 β)及 p5 3蛋白在涎腺腺样囊性癌 (salivaryadenoidcysticcarcinoma ,SACC)中表达分布特征的研究 ,探讨其在该肿瘤发生发展中的作用及临床病理意义。方法　应用免疫组化技术检测 45例SACC及 12例正常涎腺组织中蛋白激酶CK2 β及 p5 3的表达变化。结果　SACC标本中蛋白激酶CK2 β阳性 37例 ,阴性 8例 ;正常腺体组织中蛋白激酶CK2 β阳性 2例 ,阴性 10例 (P <0 0 1) ;p5 3在SACC标本中阳性 6例 ,阴性 39例。二者的表达在病理学各分型及临床各分期之间无显著差异 (P >0 0 5 )。结论　蛋白激酶CK2 β在SACC组织中呈高表达 ,与其相关的 p5 3在SACC中呈低表达。但二者与SACC病理学分型及临床分期无关。     

R钙粘蛋白抑制涎腺腺样囊性癌的侵袭和转移

目的 明确R钙粘蛋白（R-cadherin,R-cad）在涎腺腺样囊性癌（salivary adenoid cystic carcinoma,SACC）中的作用。方法 首先通过免疫组织化学染色比较R-cad在涎腺腺样囊性癌组织和癌旁正常涎腺组织中的表达差异。之后,选取涎腺腺样囊性癌高转移细胞株SACC-LM,通过siRNA干扰技术有效下调R-cad表达,通过迁移小室迁移实验和侵袭小室侵袭实验以及裸鼠肺转移瘤模型实验,检测R-cad表达下调后,SACC-LM细胞迁移和侵袭能力的改变。结果 免疫组织化学染色显示,相对于癌旁正常涎腺组织,R-cad在涎腺腺样囊性癌组织中的表达量降低;迁移小室和侵袭小室实验证明,Rcad表达下调后,SACC-LM细胞的迁移能力和侵袭能力增强;裸鼠肺转移瘤模型实验证明,R-cad表达下调的SACC-LM细胞在裸鼠体内形成更多的肺转移灶。结论 在涎腺腺样囊性癌中R-cad可能有抑制涎腺腺样囊性癌细胞迁移、侵袭和远处转移的作用。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission

The molecular characterisation of species and genotypes of Cryptosporidium and Giardia is essential for accurately identifying organisms and assessing zoonotic transmission. Results of recent molecular epidemiological studies strongly suggest that zoonotic transmission plays an important role in cryptosporidiosis epidemiology. In such cases the most prevalent zoonotic species is Cryptosporidium parvum. Genotyping and subtyping data suggest that zoonotic transmission is not as prevalent in the epidemiology of giardiasis. Molecular characterisation of Cryptosporidium and Giardia is a relatively recent application that is evolving as new genes are found that increase the accuracy of identification while discovering a greater diversity of species and yet unnamed taxa within these two important genera. As molecular data accumulate, our understanding of the role of zoonotic transmission in epidemiology and clinical manifestations is becoming clearer.     

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent.faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium -like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum , shared characteristics with Ent. columbae.
The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol.
Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.     

Coiled-coil nanomechanics and uncoiling and unfolding of the superhelix and alpha-helices of myosin

The nanomechanical properties of the coiled-coils of myosin are fundamentally important in understanding muscle assembly and contraction. Force spectra of single molecules of double-headed myosin, single-headed myosin, and coiled-coil tail fragments were acquired with an atomic force microscope and displayed characteristic triphasic force-distance responses to stretch: a rise phase (R) and a plateau phase (P) and an exponential phase (E). The R and P phases arise mainly from the stretching of the coiled-coils, with the hinge region being the main contributor to the rise phase at low force. Only the E phase was analyzable by the worm-like chain model of polymer elasticity. Restrained molecular mechanics simulations on an existing x-ray structure of scallop S2 yielded force spectra with either two or three phases, depending on the mode of stretch. It revealed that coiled-coil chains separate completely near the end of the P phase and the stretching of the unfolded chains gives rise to the E phase. Extensive conformational searching yielded a P phase force near 40 pN that agreed well with the experimental value. We suggest that the flexible and elastic S2 region, particularly the hinge region, may undergo force-induced unfolding and extend reversibly during actomyosin powerstroke.     

Carnitine and creatine content of tissues of normal and alloxan-diabetic sheep and rats

The concentration of carnitine in liver increased 28-fold and urinary carnitine excretion 5-fold in alloxan-diabetic sheep. In contrast there were no similar increases in alloxan-diabetic rats. The creatine content of liver decreased 3-fold and creatine excretion decreased 2-fold in diabetic sheep. In contrast the creatine content of liver increased nearly 4-fold in diabetic rats with no change in creatine excretion. The marked increased in production of carnitine by the liver of the diabetic sheep appears possible because of decreased production and excretion of creatine.