Ciliates rapidly enhance the frequency of conjugation between Escherichia coli strains through bacterial accumulation in vesicles

The mechanism underlying bacterial conjugation through protozoa was investigated. Kanamycin-resistant Escherichia coli SM10λ⁺ carrying pRT733 with TnphoA was used as donor bacteria and introduced by conjugation into ciprofloxacin-resistant E. coli clinical isolate recipient bacteria. Equal amounts of donor and recipient bacteria were mixed together in the presence or absence of protozoa (ciliates, free-living amoebae, myxamoebae) in Page’s amoeba saline for 24 h. Transconjugants were selected with Luria broth agar containing kanamycin and ciprofloxacin. The frequency of conjugation was estimated as the number of transconjugants for each recipient. Conjugation frequency in the presence of ciliates was estimated to be approximately 10^?6, but in the absence of ciliates, or in the presence of other protozoa, it was approximately 10^?8. Conjugation also occurred in culture of ciliates at least 2 h after incubation. Successful conjugation was confirmed by the polymerase chain reaction. Addition of cycloheximide or latrunculin B resulted in suppression of conjugation. Heat killing the ciliates or bacteria had no effect on conjugation frequency. Co-localization of green fluorescent protein-expressing E. coli and PKH-67-vital-stained E. coli was observed in the same ciliate vesicles, suggesting that both donor and recipient bacteria had accumulated in the same vesicle. In this study, the conjugation frequency of bacteria was found to be significantly higher in vesicles purified from ciliates than those in culture suspension. We conclude that ciliates rapidly enhance the conjugation of E. coli strains through bacterial accumulation in vesicles.     

Features and clinical implications of hepatitis B virus genotypes and mutations in basal core promoter/precore region in 507 Chinese patients with acute and chronic hepatitis B

BackgroundThe association of hepatitis B virus (HBV) genotypes and basal core promoter (BCP) and precore (PC) mutations with the clinical characteristics is increasingly recognized.ObjectiveTo investigate virologic features and clinical implications of HBV genotypes, BCP and PC mutations between large-size patients with acute hepatitis B (AHB) and chronic hepatitis B (CHB).Study designOne hundred and eighty-two AHB patients and 325 CHB patients were investigated. HBV genotypes and BCP/PC mutations were determined by direct sequencing. Mutations at 10 interested sites of the BCP/PC region were compared between the two groups of patients.ResultsAHB patients had a significantly higher ratio of genotype B to C than CHB patients (37.4–62.6% vs. 16.6–83.4%, P < 0.001). The prevalence of BCP/PC wild-type virus was 60.4% in AHB patients in contrast to 28.9% in CHB patients. Significantly lower prevalence of A1762T, G1764A, G1896A, and G1899A but higher prevalence of T1758C was found in AHB patients. Interestingly, T1758C and A1762T/G1764A appeared mutual restraint. Genotype B virus had lower BCP mutation frequency and similar PC mutation frequency compared to genotype C virus. AHB patients with BCP/PC mutant virus had higher viral load, whereas CHB patients with BCP/PC mutant virus had lower viral load and elevated alanine aminotransferase, in comparison with those with the wild-type virus.ConclusionPatients with genotype B virus, BCP/PC wild-type virus or T1758C mutant virus were more susceptible to develop AHB, whereas high prevalence of the BCP/PC mutations was associated with CHB development.     

注射用Rtnf的全身过敏性和血管局部刺激性作用研究

目的:观察Rtnf是否具有血管刺激作用、全身过敏反应,评价其注射用药的安全性。方法:通过家兔耳缘静脉刺激实验、豚鼠全身主动过敏实验(ASA)观察注射用药Rtnf的安全性。结果:注射用Rtnf对家兔血管内皮无损伤和刺激作用,病理切片观察,耳廓皮肤的表皮和真皮各结构完好,未见变性、坏死、缺失,表皮下乳头层及网织层无炎细胞渗出、无出血,血管内无血栓形成,附件结构正常;豚鼠未出现过敏现象。结论:在本次实验条件下,注射用Rtnf溶血性试验符合注射用药安全性要求;无血管刺激作用;对豚鼠不致敏。     

HCVE2-gAD融合DNA疫苗的构建及其细胞免疫效果评价

目的 将丙型肝炎病毒（Hepatitis C virus,HCV）包膜糖蛋白E_2与脂联素球部结构域（gAD）进行基因融合后构建DNA疫苗,并通过免疫小鼠评价其所诱发的HCV E_2特异性细胞免疫应答.方法 根据E_2与gAD的基因序列设计引物,分别扩增出不含跨膜区的E_2基因和添加连接肽的gAD基因,再利用重叠PCR将二者融合,以pVRC为载体构建DNA疫苗质粒,经体外转染293T细胞并用Western Blot证实其表达后,采用皮内注射加卡钳电极电转的方式于0、3、6周免疫BALB/c小鼠,取脾细胞进行ELISPOT检测分析其所诱发的E_2特异性T细胞免疫应答水平.结果 成功构建了能有效表达E_2-gAD融合蛋白的新型DNA疫苗,经皮内电转方式免疫小鼠后可获得比单独E_2疫苗更强的HCV特异性T细胞免疫应答.结论 gAD基因的融入可在一定程度上增强疫苗的免疫原性,为新型HCV DNA疫苗的进一步发展和优化莫定基础.     

丙型肝炎病毒亚单位融合蛋白的表达及免疫原性测定

目的获得高纯度的丙型肝炎亚单位融合蛋白并评价其免疫原性。方法利用原核表达系统,以pET—11d作为载体,在大肠埃希菌BL21（DE3）中经IPTG诱导表达获得融合蛋白,之后采用DEAE阴离子交换和镍离子柱亲和层析进行纯化。通过Western Blot验证融合蛋白的抗原活性。同时以该蛋白免疫实验动物后测定血清中的抗体滴度。结果成功获得很高纯度的丙型肝炎亚单位融合蛋白,EIA显示融合蛋白能够诱生出高滴度的抗体。结论原核表达系统表达的丙型肝炎病毒亚单位融合蛋白具有较强的免疫原性,为丙型肝炎病毒治疗性和预防性疫苗的研制提供了一条新的途径。     

血清HE4、TPS和CA125联检在卵巢癌诊断中的应用价值

目的：探讨血清人附睾分泌蛋白4（HE4）、组织特异性抗原（TPS）和CA125联检在卵巢癌诊断中的应用价值。方法：采用EIA、ELISA和ECLIA分别检测卵巢癌患者（n=30）、卵巢良性疾病患者（n=30）和健康对照者（n=31）的血清HE4、TPS和CA125血清水平。结果：卵巢癌组与卵巢良性疾病组、健康对照组、卵巢良性疾病组＋健康对照组比较,血清HE4、TPS和CA125的水平都有显著统计学差异（P〈0.01）。HE4在64.28pmol/L时约顿指数最大（0.667）,敏感性为70.0%,特异性为96.7%,ROC-AUC为0.878;TPS在63.20U/L时约顿指数最大（0.469）,敏感性为63.3%,特异性为83.6%,ROC-AUC为0.761;CA125在48.86U/ml时约顿指数最大（0.602）,敏感性为73.3%,特异性为86.9%,ROC-AUC为0.836;HE4＋CA125联检后敏感性为93.3%,特异性为82.0%,ROC-AUC为0.938;HE4＋CA125＋TPS联检后敏感性为93.3%,特异性为86.9%,ROC-AUC为0.941;HE4与CA125、HE4＋CA125、HE4＋CA125＋TPS比较ROC-AUC无显著差异,HE4和CA125联检后其ROC-AUC增大为0.938,与CA125、TPS二个单项指标相比,P值均〈0.05,与HE4、CA125、TPS三个指标联检后的ROC-AUC值0.941比较P〉0.05,不存在统计学差异。结论：血清HE4是卵巢癌诊断的良好指标,HE4和CA125联检是理想的组合方式,兼顾了敏感性和特异性,提高了对卵巢癌的诊断能力。     

MRI图像的虚拟膀胱镜三维显示技术

目前对于膀胱癌的诊断最准确可靠的方法是光学膀胱镜,但光学膀胱镜是一种有创的检测方法,价格昂贵视野有限,不适合作为常用的筛查方法。我们希望使用基于医学影像和图像处理方法的虚拟膀胱镜技术实现对光学膀胱镜的有效替代。本文使用T1加权的MRI膀胱图像,对水平集方法分割后的膀胱壁图像使用marching cubes算法进行面绘制,并对得到的三角网格做简化和平滑处理,利用vtk平台实现虚拟膀胱镜的显示。实验结果表明使用该方法可以成功实现膀胱壁的3d显示,方便医生诊断。     

Voxel-based assessment of gray and white matter volumes in Alzheimer's disease

Using the study-specific templates and optimized voxel-based morphometry (VBM), this study investigated abnormalities in gray and white matter to provide depiction of the concurrent structural changes in 13 patients with Alzheimer's disease (AD) compared with 14 age- and sex-matched normal controls. Consistent with previous studies, patients with AD exhibited significant gray matter volume reductions mainly in the hippocampus, parahippocampal gyrus, insula, superior/middle temporal gyrus, thalamus, cingulate gyrus, and superior/inferior parietal lobule. In addition, white matter volume reductions were found predominately in the temporal lobe, corpus callosum, and inferior longitudinal fasciculus. Furthermore, a number of additional white matter regions such as precentral gyrus, cingulate fasciculus, superior and inferior frontal gyrus, and sub-gyral in parietal lobe were also affected. The pattern of gray and white matter volume reductions helps us understand the underlying pathologic mechanisms in AD and potentially can be used as an imaging marker for the studies of AD in the future.     

Hepatoprotective effects of berberine on carbon tetrachloride-induced acute hepatotoxicity in rats

Background  

Berberine is an active compound in Coptidis Rhizoma (Huanglian) with multiple pharmacological activities including antimicrobial, antiviral, anti-inflammatory, cholesterol-lowering and anticancer effects. The present study aims to determine the hepatoprotective effects of berberine on serum and tissue superoxide dismutase (SOD) levels, the histology in tetrachloride (CCl₄)-induced liver injury.     

Modulation of mesenchymal stem cells behaviors by chitosan/gelatin/pectin network films

In this article, the chitosan/gelatin/pectin (CGP) network films were prepared to build appropriate physicochemical and mechanical microenvironment for attachment, proliferation, and differentiation of mesenchymal stem cells (MSCs). Results suggested that the hydrophilicity and mechanical character of CGP composites films could be modulated via adjusting the pectin content in the composites. The investigations of attachment and proliferation behaviors of mesenchymal stem cells (MSCs) on the CGP films were carried out. The morphology of cells was observed with hematoxylin/eosin staining (HE) and scanning electron microscope (SEM). The osteogenic differentiation of MSCs was investigated via ALP and polymerase chain reaction (PCR). Results suggested that the CGP films have excellent biocompatibility. MSCs seeded on CGP (0.1) film show higher proliferation capacity compared with other samples. Moreover, osteogenic differentiation of MSCs also depends on the properties of the substrate. The MSCs seeded on CGP (0.5) expressed the highest ALP activity, osteogenic gene expression and mineral formation capacity. These results suggest that the composition of the CGP network films could effectively modulate their physicochemical and mechanical properties and further regulate the cell behaviors of MSCs.