Evolutionary and developmental origins of the cardiac neural crest: Building a divided outflow tract

The cardiac neural crest cells (CNCCs) have played an important role in the evolution and development of the vertebrate cardiovascular system: from reinforcement of the developing aortic arch arteries early in vertebrate evolution, to later orchestration of aortic arch artery remodeling into the great arteries of the heart, and finally outflow tract septation in amniotes. A critical element necessary for the evolutionary advent of outflow tract septation was the co‐evolution of the cardiac neural crest cells with the second heart field. This review highlights the major transitions in vertebrate circulatory evolution, explores the evolutionary developmental origins of the CNCCs from the third stream cranial neural crest, and explores candidate signaling pathways in CNCC and outflow tract evolution drawn from our knowledge of DiGeorge Syndrome. Birth Defects Research (Part C) 102:309–323, 2014. © 2014 Wiley Periodicals, Inc.     

引发下呼吸道感染的非发酵菌的菌群分布及耐药性分析

目的了解引发下呼吸道感染的非发酵菌的菌群分布及耐药性分析,为临床合理使用抗生素提供依据。方法对2011年1月至2013年9月深圳罗岗医院门诊及住院患者痰标本分离的非发酵菌的菌群分布及优势菌的耐药性进行回顾性分析。结果702株非发酵菌中铜绿假单胞菌（PA）362株,占51．6％,鲍氏不动杆菌（AB）158株,占22．5％;PA对NIT、CXM、SAM、AMP、CZO、CTF、CRO、SXT耐药率均在99．0％以上,对IPM、LVF和TZP耐药率均在15．0％以下;AB对NIT、CXM、AMP、CZO、CTT耐药率均为100％,对SAM、FEP、TOB、GEN、IPM、LVF和TZP耐药率均在15．0％以下;耐IPM的PA和AB的检出率分别为20．4％和11．4％;耐IPM的PA对NIT、CXM、SAM、AMP、CZO、CTT、CRO、SXT、1PM耐药率均为100％,对其余10种抗生素的耐药率在25．0％～84．0％;耐IPM的AB对NIT、CXM、AMP、CZO、CTT、CRO、SXT、ATM、PIP、IPM耐药率均为100％,对其余9种抗生素的耐药率在21．0％～90．0％。结论引发下呼吸道感染的非发酵菌以PA和AB为主且耐药现象严重,临床医师在选择抗菌药物前应重视病原学培养,根据药敏试验选择用药。     

肺结核合并非发酵菌下呼吸道感染的临床特征及耐药性分析

目的了解肺结核患者合并非发酵菌下呼吸道感染的临床特征及耐药性,为临床合理使用抗菌药物提供依据。方法采用ATB全自动细菌鉴定仪,对临床分离菌株进行菌种鉴定,用K．B法对非发酵菌做药物敏感试验。结果从肺结核患者下呼吸道标本中共分离非发酵菌156株,其中铜绿假单胞菌最多,占46．5％,其次为鲍曼不动杆菌和嗜麦芽寡养单胞菌,分别占37．8％和9．6％。药敏试验显示5种非发酵菌对多种抗生素均表现为高度耐药或多重耐药,高于相关研究,差异有统计学意义（P≤0．05）。结论肺结核患者肺部感染非发酵菌的分离率较高,多重耐药现象严重,临床应重视非发酵菌感染和耐药性监测。     

风湿性疾病患者尿路感染大肠埃希菌对左氧氟沙星耐药性及危险因素分析

目的研究风湿性疾病中尿路感染大肠埃希菌对左氧氟沙星耐药性及相关危险因素。方法中国医科大学附属第一医院风湿免疫科2009年1月至2013年12月125株住院患者清洁中段尿培养所分离出大肠埃希菌,依据是否耐药分为两组。分析耐药组相关危险因素。结果 5年来大肠埃希菌对左氧氟沙星耐药率呈逐渐上升趋势。耐药组对氨苄西林、环丙沙星、头孢曲松、哌拉西林、复方新诺明的耐药率高于非耐药组,两组间差异有统计学意义（P〈0.05）。慢性病程、既往喹诺酮类药物应用史、既往尿路感染、菌株产ESBLs为耐药危险因素。各风湿性疾病间耐药率比较差异未见统计学意义。结论风湿性疾病尿路感染危险因素与其他疾病尿路感染危险因素类似。临床工作中应加强对危险因素监视和控制。     

4103例泌尿生殖道支原体感染及药敏分析

目的通过分析泌尿生殖道支原体感染及药敏情况,为临床提供用药指导。方法采用支原体检测试剂盒进行支原体属培养和药敏试验。结果4103例患者标本中,检出支原体属1336株,总阳性率为32．56％;其中单一解脲脲原体（Uu）感染1227例,阳性率为91．84％;单纯人型支原体（Mh）感染15例,阳性率为1．12％;Uu＋Mh混合合感染94例,阳性率为7．04％。解脲脲原体对阿奇霉素、红霉素、交沙霉素、罗红霉素、米诺环素、强力霉素敏感性高;单纯人型支原体对交沙霉素、米诺环素、强力霉素敏感。结论泌尿生殖道支原体感染以Uu为主。支原体大多具有多重耐药性,临床治疗需根据药敏结果选药物。     

Polypyrimidine tract binding protein inhibits IgM pre-mRNA splicing by diverting U2 snRNA base-pairing away from the branch point

The mouse immunoglobulin (IgM) pre-mRNA contains a splicing inhibitor that bears multiple binding sites for the splicing repressor polypyrimidine tract binding protein (PTB). Here we show that the inhibitor directs assembly of an ATP-dependent complex that contains PTB and U1 and U2 small nuclear RNAs (snRNAs). Unexpectedly, although U2 snRNA is present in the inhibitor complex, it is not base-paired to the branch point. We present evidence that inhibitor-bound PTB contacts U2 snRNA to promote base-pairing to an adjacent branch point–like sequence within the inhibitor, thereby preventing the U2 snRNA–branch point interaction and resulting in splicing repression. Our studies reveal a novel mechanism by which PTB represses splicing.     

Dynamic excitation states and firing patterns are controlled by sodium channel kinetics in myenteric neurons: a simulation study

Enteric neurons located in the gastro-intestinal tract are of particular importance to control digestive functions such as motility and secretion. In our recent publication, we showed that mouse myenteric neurons exhibit 2 types of tetrodotoxin-resistant Na⁺ currents: a fast inactivating Na⁺ current produced by Nav1.5 channels, present in nearly all myenteric neurons, and a persistent Na⁺ current attributed to Nav1.9 channels, restricted to the intrinsic primary afferent neurons (IPANs). By combination of experimental recording and computer simulation we found that Nav1.5 contributed to the upstroke velocity of action potentials (APs), whereas Nav1.9 opposed AP repolarization. Here, we detailed the Na⁺, Ca²⁺ and K⁺ currents used in our computational model of IPAN. We refined the prototype cell to reproduce the sustained firing pattern recorded in situ. As shown in experimental conditions we demonstrated that Nav1.9 channels critically determine the up-state life-time and thus, are essential to sustain tonic firing.     

Exposure to female pheromones stimulates a specific type of neuronal population in the male but not female magnocellular division of the medial preoptic nucleus (MPN mag) of the Syrian hamster

The magnocellular division of the medial preoptic area (MPN mag) integrates pheromonal and hormonal signals to play a critical role in the expression of male typical sex behavior. The MPN mag contains two morphologically distinct neuronal populations; the percentage of each type within the nucleus is sex specific. Males have more neurons with a single nucleolus whereas females have more with multiple nucleoli. To determine which neuronal subtype mediates pheromonal induction of copulation, tissue from male and female hamsters exposed to female pheromones was immunolabeled for the immediate early protein (EGR-1). Subsequently the tissue was counterstained and the number of ERG-1 neurons with one or two nuclei was determined. The results indicate that pheromones stimulate neurons with single nucleoli in males but fail to stimulate either neuronal subtype in females suggesting that synaptic input to the MPN mag is sexually differentiated.     

Application of Human Adenovirus Genotyping by Phylogenetic Analysis in an Outbreak to Identify Nosocomial Infection

Nosocomial infections are common in pediatric patients and can be fatal in infants and immunocompromised patients. In September 2018, a high positive rate of human adenovirus HAdV was occurred among hospitalized children in the Children's Hospital Affiliated to the Capital Institute of Paediatrics in Beijing. To investigate whether this outbreak of HAdV was related to nosocomial infections or the result of community infections, we collected respiratory specimens from patients with acute respiratory infections in a respiratory ward during June to December 2018, and screened for respiratory viruses. Among 1,840 cases included, 95(5.2%, 95/1840) were positive for HAdV and 81 were genotyped based on phylogenetic analysis, including seven as HAdV-1(8.6%), 30 HAdV-3(37.0%), two HAdV-6(2.5%), and 42 HAdV-7(51.9%). More HAdV-positive samples were collected in August(4.7%, 12/255), September(15.0%, 41/274) and October(6.9%, 17/247), with a peak in September 2018. By combining the results of HAdV phylogenetic analysis with clinical data of patients, there were 77 cases(4.2%, 77/1840; 81.1%, 77/95) excluded from nosocomial infections, eight cases representing possible infections transmitted by visitors or attending parents, three cases without sequences that might have been due to infection transmitted by roommates positive for HAdV, one case of a roommate without an HAdV sequence, and six cases that shared highly homologous sequences with those of their roommates, for which nosocomial infections might be considered. In conclusion, genotyping of HAdVs based on phylogenetic analysis combined with clinical information provides a powerful method to distinguish nosocomial infections from community acquired infection, especially when tracing the origins of nosocomial infections.     

Morphology of the digestive system in carnivorous freshwater dourado Salminus brasiliensis

The digestive system of teleost shows remarkable functional and morphological diversity. In this study, the digestive tract and accessory organs of dourado Salminus brasiliensis are characterized using anatomical, histological, histochemical and immunohistochemical analyses. The existence of taste buds bordered by microridges in the oesophagus of dourado was recorded for the first time, thus showing that the species drives food intake by either swallowing or rejecting the food item. The Y-shaped stomach of dourado consisted of cardiac, cecal and pyloric regions with tubular gastric glands registered solely in the cardiac and cecal segments. The intestine is a short N-shaped tube with two loops, an intestinal coefficient of 0.73. The structure of pyloric caeca is similar to that of the intestine wall, comprising tunica mucosa, tela submucosa, tunica muscularis and tunica serosa layers. Histochemical analyses revealed an increased incidence of goblet cells from the midgut to the hindgut segment. A well-developed enteric plexus of scattered nerve cell and fibres are found along the digestive tract, and the calcitonin gene-related peptide (CGRP) immunoreactive neurons and fibres were identified in the myenteric plexus from the oesophagus to the hindgut. The exocrine pancreas appears diffuse in the mesentery around the stomach, intestine and also reaches the liver, and the endocrine pancreas is organized as a few islets of Langerhans. The liver comprises three distinct, asymmetric lobes, and the portal triad arrangement was registered in this tissue.