Molecular typing of Clostridioides difficile isolates from clinical and non‐clinical samples in Iran

Clostridioides difficile is a major cause of nosocomial infectious diarrhea in hospitalized patients throughout the world. We aimed to characterize C. difficile isolates among hospitalized patients, hospital staffs, and hospital environment samples obtained in three tertiary care hospitals of Iran with regard to their molecular types between June 2016 and November 2017. The toxigenicity of C. difficile isolates was determined by toxigenic culture and multiplex‐PCR. Toxigenic C. difficile isolates collected were ribotyped using capillary gel electrophoresis‐based PCR and the database of WEBRIBO ( http://webribo.ages.at ). Of 500 clinical and non‐clinical samples, toxigenic C. difficile were identified in 35 of 250 stool samples (14%) and in 3 of 250 swabs (1.2%). The most frequently found ribotypes (RTs) were 039, AI‐12, and AI‐21 (15.8, 10.52, and 10.52% of all isolates, respectively). Further RTs were: 017, 001, AI‐3, AI‐15, AI‐18, AI‐10, AI‐4, and PR21195 (as new ribotype). The epidemic RTs (027 and 078) seen in the Europe, North America, and Asia were completely absent in this study.     

耐碳青霉烯类肺炎克雷伯菌耐药基因检测及同源性

目的探讨耐碳青霉烯类肺炎克雷伯菌(CRKP)耐药基因型及同源性。方法收集某院2015年9月—2016年2月临床标本分离的38株CRKP,采用聚合酶链反应(PCR)方法检测耐药基因型,脉冲场凝胶电泳(PFGE)分析菌株同源性。结果 38株CRKP主要来源于重症监护病房(ICU)及外科重症监护病房(SICU),分别占39.48%、34.21%。38株CRKP均检出blaKPC和blaSHV耐药基因,6株检出blaCTX耐药基因。PFGE显示共分成A、B、C、D4个谱型,其中以C型为主(65.78%,25/38)。A型菌株中菌株14、15、16携带blaKPC-2型、blaSHV型、blaCTX-M-15耐药基因,此3株细菌均是SICU患者分离的,菌株14和15分离自同一天,菌株16分离时间延后一周;C型菌株中,菌株10、18、25、28的同源性为100%,菌株10、18分离自ICU患者,菌株25、28分离自神经内一科患者(均从ICU转出),均是在ICU住院期间检出,且分离时间相差1 d。结论该院CRKP耐药基因型以blaKPC及blaSHV为主,存在克隆株医院内流行。     

阴离子、阳离子检测方法研究进展

近几十年来，阴、阳离子检测方法的发展非常迅速，检测方法有了较大的改进，同时离子种类得到很大的丰富。根据不同的药物分析目的可选择不同的检测方法，以取得最好的检测精度和灵敏度。简要地介绍了用于检测药物中常用的阴、阳离子的比浊法、比色法、滴定法、离子选择电极法、可见-紫外分光光度法、原子吸收分光光度法与色谱法等分析方法，并对今后的研究方向进行了展望。     

Spider Angiomas in Patients with Liver Cirrhosis: Role of Alcoholism and Impaired Liver Function

A study was undertaken to compare two new methods of capillary blood flow measurement, namely fluorescein flowmetry (FF) and laser Doppler flowmetry (LDF). The blood flow was measured in a pelvic pouch during its construction and in the completed ileoanal anastomosis in 12 patients. There was a high correlation between the two methods (correlation coefficient, 0.78) (p <0.01) when the blood flow was measured in the pelvic pouch. The correlation coefficient between the two methods for the difference between the blood flow in the pelvic pouch at the site of the planned anastomosis when the pouch resided in the abdomen and that in the completed ileoanal anastomosis was r = 0.99 (n = 12, p< 0.001); the reduction amounted to 25% as measured by FF and 27% as measured by LDF (n = 12, p < 0.01). All ileoanal anastomoses healed perfectly, the lowest FF and LDF values being 0.004 density units/sec and 0.3 V, respectively. The results indicate that either method can be considered for measuring capillary blood flow.     

IDENTIFICATION OF TWO NEW β-THALASSEMIA SPLICE MUTATIONS: IVS-I-1 (G → C) AND IVS-I (−2) (A → C)

Hb Constant Spring [Hb CS; α142, Term→Gln (TAA>CAA in α2)] is a nondeletional α-thalassemia (α-thal) defect difficult to detect on conventional electrophoresis because of its small amount in heterozygotes. We have found that individuals with an Hb CS trait could efficiently be detected using the Sebia capillarys 2 system. In the present study, we have confirmed this method in a cohort of 23,842 individuals from Guangdong Province (South China). Hb CS was detected in 71 (0.3%) of the cases. The levels of Hb CS in heterozygotes ranged from 0.1–1.0% with an average of 0.6%. We propose the reported 0.3% as a realistic figure for the prevalence of Hb CS in South China.     

Characterisation of Crevice and Pit Solution Chemistries Using Capillary Electrophoresis with Contactless Conductivity Detector

The ability to predict structural degradation in-service is often limited by a lack of understanding of the evolving chemical species occurring within a range of different microenvironments associated with corrosion sites. Capillary electrophoresis (CE) is capable of analysing nanolitre solution volumes with widely disparate concentrations of ionic species, thereby producing accurate and reliable results for the analysis of the chemical compositions found within microenvironment corrosion solutions, such as those found at crevice and pit corrosion sites. In this study, CE with contactless conductivity detection (CCD) has been used to characterize pitting and crevice corrosion solution chemistries for the first time. By using the capillary electrophoresis with contactless conductivity detection (CE-CCD) system, direct and simultaneous detection of seven metal cations (Cu²⁺, Ni²⁺, Fe³⁺, Fe²⁺, Cr³⁺, Mn²⁺, and Al³⁺) and chloride anions was achieved with a buffer solution of 10 mM 2,6-pyridinedicarboxylic acid and 0.5 mM cetyltrimethylammonium hydroxide at pH 4 using a pre-column complexation method. The detection limits obtained for the metal cations and chloride anions were 100 and 10 ppb, respectively. The CE-CCD methodology has been demonstrated to be a versatile technique capable of speciation and quantifying the ionic species generated within artificial pit (a pencil electrode) and crevice corrosion geometries for carbon steels and nickel-aluminium bronze, thus allowing the evolution of the solution chemistry to be assessed with time and the identification of the key corrosion analyte targets for structural health monitoring.     

非接触式共培养体外血脑屏障模型的跨膜电阻及通透性

目的建立大鼠脑毛细血管内皮细胞(BCEC)与星形胶质细胞共培养血脑屏障模型并评价其功能。方法采用SD大鼠原代分离培养获得BCEC和星形胶质细胞。经细胞形态学观察、免疫组化检测相关抗原后建立非接触式共培养血脑屏障模型,测定共培养模型所形成的跨细胞电阻及荧光素钠的通透性。采用LC-MS检测6个化合物透过血脑屏障模型的通透性,并与文献报道的体内数据进行比较。结果培养的BCEC多数为短梭形外观,免疫组化检测可见细胞高表达因子Ⅷ;星形胶质细胞呈现具有细胞突起的典型形态,免疫组化检测可见细胞高表达胶质纤维酸性蛋白。共培养的体外血脑屏障模型跨BCEC单层的电阻值为(373±41)Ω·cm2,荧光素钠跨BCEC单层的通透性为(0.34±0.14)×10-3cm·min-1,符合体外血脑屏障模型要求。对所选6个化合物体内外透过BBB模型渗透系数的比较,表明具有一定的相关性(R2=0.7679,P<0.05)。结论建立的体外BBB模型在跨内皮电阻和通透性方面具备了在体BBB的基本特性,可以用于模拟体内环境,进行药物早期筛选方面的研究。     

Multiple Wall In-folds Sub-divide Single Segments During Capillary Regression in Hyperoxic Acute Lung Injury

Abstract

The present study provides further insight into the structural processes that remodel pulmonary capillaries in the injured adult lung. Early in hyperoxia acute lung injury (HALI), many sub-dividing segments are present throughout the capillary network before segment occlusion and loss predominate and capillary density decreases later in the period. A second segment sub-division triggered in regenerating capillaries after air breathing (post-HALI) demonstrates a similar mechanism of organization at a time of contrasting change in the capillary density. As we have previously reported, the process of segment sub-division includes in-folding of the endothelial-epithelial surface (alveolar–capillary membrane) to form inter-luminal structures (ILSs) and loops, with loop separation increasing segment number. Unexpectedly, the findings support remodeling of the capillary density by wall in-folding in acute lung injury, demonstrating a similar mechanism in capillary regression as well as in regeneration in the adult lung.