酒精性肝病大鼠创伤弧菌脓毒症各脏器的超微结构观察

目的观察酒精性肝病大鼠创伤弧菌脓毒症重要脏器的超微结构变化,探讨研究创伤弧菌的致病性。方法采用酒精灌胃联合自由饮酒法制做大鼠酒精性肝病模型,取成模大鼠12只,分成2组,实验组6×108cfu/mL浓度创伤弧菌右下肢皮下注射感染肝病大鼠;对照组等量生理盐水右下肢皮下注射。48 h后颈动脉取血液及患肢病变组织进行细菌培养,留取肝脏、心脏、肺脏、肾脏、脾脏、右下肢肌肉、大脑等脏器组织0.1 cm×0.1 cm×0.1 cm置电镜固定液,超薄切片观察超微结构。结果实验组大鼠12 h后,皮温升高,右下肢明显肿胀、皮肤发紫,精神萎靡,活动减少,呼吸急促,均在48 h内濒临死亡,血液及患肢病变组织培养出创伤弧菌,电镜下见心肌、肺、肝、肾等组织的部分实质细胞内和间质中有创伤弧菌生长,肝脏、心脏、肺脏、肾脏、脾脏、右下肢肌肉、大脑存在不同程度超微结构改变,部分血管内皮细胞损伤及基膜断裂溶解,线粒体、内质网等细胞器损伤明显,其中以下肢骨骼肌、肺、肝脏的超微结构改变尤为明显,脾脏的改变相对较轻。结论创伤弧菌感染酒精性肝病大鼠后导致多个脏器的实质细胞及间质超微结构损伤,致使多器官功能障碍甚或衰竭,是导致机体快速死亡的重要原因。     

肝病大鼠创伤弧菌脓毒症基质金属蛋白酶-9的动态变化

目的 探讨血清MMP-9水平与酒精性肝病大鼠创伤弧菌脓毒症进展的关系.方法 制作酒精性肝病大鼠创伤弧菌脓毒症模型,分脓毒症组及抗菌药物干预组.观察脓毒症组大鼠在染菌后2 h、6 h、12 h、24 h各时间点的脓毒症表现及光镜下肺组织病理改变,并以ELISA法测定脓毒症组及抗菌药物干预组大鼠染菌后各时间点血清MMP-9水平.计量资料采用(x±S)表示.采用SPSS 10.0进行统计,各组血清MMP-9值作t检验,多组间差异采用单囚素方差分析处理.P＜0.05为差异有统计学意义.结果 脓毒症组大鼠染菌后6 h开始出现较明显的毒血症状,并随时间的延长加剧,24 h达高峰,濒临死亡.光镜下肺组织损伤以炎症细胞浸润及肺泡壁水肿充血为主,6 h较轻,12 h损伤加重,到24 h可见大量的炎细胞浸润,淋巴滤泡形成,伴肺泡腔出血.脓毒症组血清MMP-9水平染菌后6 h明显升高(P＜0.01),12 h达高峰,24 h已明显下降(P＜0.01,与12 h组比).抗菌药物干预组大鼠血清MMP-9变化曲线与脓毒症组一敛,但与脓毒症组相应时间点比较,仅6 h时MMP-9水平明显减低(P＜0.01).结论 MMP-9可能不是酒精性创伤弧菌脓毒症后期病情恶化的主要参与因素,血清MMP-9水平不能准确地反应酒精性肝病创伤弧菌脓毒症病情轻重及全身器官损伤的程度.     

酒精性肝病合并弧菌性脓毒症的临床及病理学特点

目的：探讨酒精性肝病合并弧菌性脓毒症患者的临床病理特点。方法：自2002年8月至2004年8月问符合酒精性肝病合并弧菌性脓毒症早期临床诊断主要依据的患者6例，在应用抗菌药物、补液扩容、升压及1～2h内切开患肢以减压、引流、清创等外科治疗，在总结其临床特点同时，观察患者下肢的临床病理特点及超微结构改变。结果：患者首先出现下肢足背或小腿肿胀、剧烈疼痛、局部红斑、数小时内血疱增多、融合成大血疱、皮肤大片淤血斑，下肢病变迅速扩大并向大腿或躯体蔓延，患者同时出现休克、MODS表现。2例下肢皮肤苍白、肌肉色红。肌酸磷酸激酶(CPK)正常或轻度升高，经清创、植皮后保存了患肢。另4例见皮肤脂肪坏死，筋膜肌肉坏死范围广．小血管血栓形成，患者的CPK明显升高，其中2例下肢病变严重，行截去患肢治疗，2例切开患肢以减压、引流、清创等病情好转，因经济原因放弃进一步治疗。6例中4例患者治愈出院。作者通过光镜及电镜对弧菌感染患者下肢病变组织系统观察，包括皮肤、肌肉、脂肪、坐骨神经、股动脉、股静脉，结合大体表现发现创伤弧菌脓毒症患者下肢病变组织病理改变主要表现为炎症性改变。结论：及早正确认识下肢临床及病理改变特点对早期临床诊断及治疗十分重要，可有效提高患者生存率。     

乌司他丁联合抗菌药对创伤弧菌脓毒症大鼠心肌的保护作用

目的观察创伤弧菌脓毒症大鼠的心肌酶变化及心肌超微结构的病理改变,探讨乌叫他厂联合抗菌药物对创伤弧菌脓毒症大鼠心肌损伤的干预作用。方法对60只成年雌性大鼠采用腹腔内注射创伤弧菌悬液建立脓毒症模型,将其分为四组,每组15只,分别为胀毒症对照组（C组）、氧氟沙星治疗组（K组）、乌司他丁治疗组（u组）、乌司他丁联合氧氟沙早治疗组（L组）。C组大鼠出现休克症状后观察各组大鼠心肌组织透射电镜下超微结构改变。H时留取血液标本,采用酶联免疫吸附剂测定法行心肌酶学检测。结果L组_人冬氰酸转氨酶（AST）、肌酸激酶（CK）、乳酸脱氢酶（LDH）、羟丁酸脱氢酶（HBDH）值均明显低于其他三组（P均〈0．01）。K组、U组仅CK值显著低于C组（P均〈0．01）,而其AST、LDH、HBDH水平与C组比较均无统计学意义（P均〉0．05）;U组与K组AST、CK、LDH、HBDH的水平差异无统计学意义（P均〉0．05）。C组大鼠心肌细胞的超微结构病变最重,K组心肌纤维的超微结构改变较少,U组心肌纤维的超微结构改变较K组多,而L组心肌纤维的结构基本正常。结论乌司他丁伍用抗菌药治疗对创伤弧菌脓毒症大鼠急性心脏损伤具有明显的保护作用。     

酒精性肝病大鼠创伤弧菌脓毒症凝血因子的动态变化

目的探讨酒精性肝病大鼠创伤弧菌脓毒症凝血因子的变化及意义。方法制作酒精性肝病大鼠创伤弧菌脓毒症模型,观察脓毒症组大鼠在染菌后2、6、12、24 h各时间点脓毒症表现,并检测各时间点大鼠血浆FIG、AT:A、tPA、PAI-1水平。结果脓毒症组大鼠染菌后6 h开始出现较明显的毒血症状,并随时间的延长而加剧,24 h达高峰,濒临死亡。脓毒症组大鼠血浆FIG在染菌后呈进行性升高,6 h始明显高于正常对照N组及酒精肝对照A5组(P<0.01),12 h达高峰,24 h FIG有下降趋势,但与12 h组相比,两者差异无统计学意义(P>0.05)。大鼠AT:A在染菌后呈进行性下降,6 h即显著低于A5及N组(P均<0.01)。tPA在染菌后2 h第1次达高峰(P<0.05),下降至正常水平后于24 h再次显著升高(P<0.01),PAI-1于2 h显著升高(P<0.01),而tPA/PAI值2 h显著降低,24 h显著高于对照组(P均<0.05)。结论酒精性肝病大鼠创伤弧菌脓毒症早期即可出现明显的凝血紊乱,动态检测FIG、AT:A、tPA、PAI-1水平可反映创伤弧菌脓毒症病情严重程度。     

头孢哌酮钠联合左氧氟沙星对创伤弧菌脓毒症大鼠组织中NSE S-100β蛋白和炎症因子的影响

目的 观察创伤弧菌脓毒症大鼠血清神经元特异性烯醇化酶(NSE)、S-100β蛋白和脑组织炎症因子的动态变化及头孢派酮钠联合左氧氟沙星的干预.方法 100只SD大鼠随机分正常对照组(A组,n=10)、创伤弧菌脓毒症组(B组,n=40)、抗菌药物干预组(C组,n=40)和抗菌药物对照组(D组,n=10)左后肢皮下注射创伤弧菌构建大鼠脓毒症模型,腹腔注射头孢派酮钠180 mg/kg和左氧氟沙星18 mg/kg干预.观察B、C组大鼠染菌后6、12、24、48 h血清NSE、S-100β,脑组织TNF-α、IL-6、IL-10转录和蛋白水平及光镜变化.结果 与A组比较,B组大鼠血清NSE、S-100β蛋白均明显升高(P<0.05),24 h达峰值.与相同时间点B组比较,C组血清NSE、S-100β 12、24、48 h均有明显减低(P<0.05).与A组比较,B组大鼠脑组织各时间点TNF-α、IL-6、IL-10转录和蛋白水平均明显升高(P<0.05),其中TNF-α在6 h即达峰值,而IL-6水平12 h达峰值,IL-10水平在48 h达峰值.与B组相同时间点比较,6、12、24 h点C组大鼠脑组织TNF-α水平明显降低,12、24、48 h点脑组织IL-6水平亦明显下调,而脑组织IL-10水平在各时间点均较B组明显升高(P<0.05).光镜下B组大鼠脑组织间质水肿严重,组织结构紊乱,炎症细胞侵润,血管扩张.C组大鼠脑组织间质水肿减轻,炎症细胞侵润程度降低.结论 NSE、S-100β蛋白的表达随着脑组织炎症的加重逐渐升高,敏感地反应创伤弧菌脓毒症脑损伤的变化.使用头孢哌酮和左氧氟沙星能有效抑制脑组织炎症反应,减轻脑损伤,减低血清NSE、S-100β蛋白的水平.     

创伤弧菌脓毒症大鼠脑组织转位蛋白的表达及抗菌药物的干预

目的 探讨创伤弧菌脓毒症大鼠脑组织转位蛋白(TSPO)基因和蛋白表达及促/抗炎因子的蛋白表达,并观察抗菌药物头孢哌酮钠联合左氧氟沙星的干预效应.方法 SD大鼠100只,随机(随机数字法)分为健康对照组(A组,n=10)、创伤弧菌脓毒症组(B组,n=40)和抗菌药物干预组(C组,n=40),抗菌药物对照组(D组,n=10).大鼠左后肢皮下注射创伤弧菌(6×108 cfu/ml,0.1 ml/100 g)制作脓毒症大鼠模型,腹腔注射头孢派酮钠180 mg/kg和左氧氟沙星18 mg/kg进行干预,以RT-PCR、Western blotting、免疫组化、ELISA等方法观察大鼠染菌后6、12、24、48 h脑组织TSPO表达、促/抗炎因子水平及电镜的特点.结果 与A组比较,B组大鼠脑组织TSPO表达水平6h即明显增高(P＜0.05),24 h达峰值.C组大鼠12、24、48 h脑组织TSPO表达水平均明显低于相同时间点B组大鼠(P＜0.05).B组大鼠脑组织各时间点TNF-α、IL-6、IL-10水平均比A组明显升高(P＜0.05),其中TNF-α在6h达峰值,IL-6 12 h达峰值,IL-10则48 h达峰值.与B组相同时间点比较,C组大鼠6、12、24 h时点脑组织TNF-α水平明显下降(P＜0.05),12、24、48 h时间点脑组织IL-6水平亦明显下调(P＜0.05),而IL-10水平在各时间点均较B组明显升高(P＜0.05).免疫组化法观察B组大鼠脑组织TSPO蛋白棕黄色颗粒密集较多,C组棕黄色颗粒较B组减少;电镜下B组大鼠脑组织神经元细胞核溶解消失,细胞及细胞器肿胀明显,C组大鼠脑组织神经元细胞核部分溶解,形态尚存,细胞及细胞器水肿减轻.结论 创伤弧菌脓毒症大鼠脑组织TSPO的表达随着脑组织炎症、病理进展逐渐增高,能敏感反映脑损伤的变化.使用头孢哌酮钠和左氧氟沙星能有效减轻脑组织炎症损伤,降低TSPO的水平.     

创伤弧菌脓毒症血浆组织因子和组织因子途径抑制物的改变及抗菌药物的影响

目的探讨大鼠创伤弧菌(VV)脓毒症血浆中组织因子(TF)和组织因子途径抑制物(TFPI)的改变以及头孢哌酮钠与乳酸左氧氟沙星联用对其的影响。方法制作大鼠VV脓毒症模型(VV组)和VV脓毒症药物干预模型(AA组),使用ELISA法测定各组大鼠血浆中TF和TFPI的含量。结果与正常对照组(NC组)相比,VV组在染菌后9 h、12 h血浆TF显著升高(P＜0．05),各时间点血浆TFPI含量无显著改变(P＞0．05);9 h、12 h的TFPI/TF比值有显著性下降(P＜0．05)。AA组染菌后9 h、12 h血浆TF明显高于NC组(P＜0．05),TFPI/TF比值在抗菌药物干预后逐渐上升,16 h时点该比值明显高于NC组(P＜0．05)。与相同时间点的VV组比较,AA组染菌后12 h血浆TF明显减低(P＜0．05),12 h、16 h血浆TFPI明显升高(P＜0．05),9 h、12 h、16 h的TFPI/TF比值亦明显升高(P＜0．05)。结论创伤弧菌脓毒症时血浆TF含量显著升高,但同期TFPI并无明显减低或升高,TFPI/TF比值减低;头孢哌酮钠联用乳酸左氧氟沙星可减低血浆TF含量,提高TFPI/TF比值。创伤弧菌脓毒症时存在明显的促凝和抗凝作用的失衡,抗菌药物干预后可使促凝和抗凝平衡被逐渐恢复。     

创伤弧菌脓毒症大鼠肝组织核转录因子-κB活性表达及抗菌药物的影响

目的探讨创伤弧菌(VV)脓毒症大鼠肝组织NF-κB活性以及抗菌药物头孢哌酮钠联用乳酸左旋氧氟沙星对其的干预效应。方法制作大鼠VV脓毒症模型(VV组)和VV脓毒症药物干预模型(AA组),使用凝胶电泳迁移率改变分析法(EMSA)测定各组大鼠肝组织NF-κB活性。结果正常大鼠肝组织NF-κB活性较低,VV组染菌2h的肝组织NF-κB活性即达到高峰,较NC组明显增高(P<0.05),后肝组织NF-κB活性逐渐减少,但VV组染菌6、9、12、16h肝组织NF-κB活性仍明显高于NC组(P<0.05)。AA组染菌后9、12h肝组织NF-κB活性仍显著高于NC组(P<0.05),后逐渐减低,染菌16h、36h、2周的肝组织NF-κB活性与NC组相比,差异无统计学意义(P>0.05)。与相应时间点的VV组相比,AA组染菌9、12、16h的肝组织NF-κB活性明显降低(P<0.05)。结论创伤弧菌脓毒症早期肝组织NF-κB活性即达高峰,及早使用头孢哌酮钠和乳酸左氧氟沙星可明显减低创伤弧菌脓毒症大鼠肝组织NF-κB活性。     

前列腺素E2对创伤弧菌感染肝病大鼠多器官损伤的保护作用

目的:通过前列腺素E2(PGE2)对创伤弧菌攻击肝病大鼠后心、肝、肺和肾等重要器官保护作用的实验观察,为PGE2应用于创伤弧菌感染的防治提供实验依据。方法:用10%的四氯化碳橄榄油溶液皮下注射制备慢性肝病大鼠,肌肉注射PGE2后用创伤弧菌腹腔注射菌液0.4mL/只,约6.0×107cfu进行攻击,并给予氧氟沙星等药物,常规电镜取材观察心、肝、肺、肾的超微结构,同时与接受相同菌量的肝病大鼠进行比较。结果:肝病大鼠创伤弧菌攻击后表现为心、肝、肺和肾等主要器官损伤严重,尤其是心肌和肺组织,而PGE2联合保护组死亡率较未经保护肝病大鼠创伤弧菌攻击组显著降低(P<0.01),心、肝、肺和肾各器官的超微结构显著改善。结论:PGE2使肝病大鼠创伤弧菌攻击后心、肝、肺和肾各器官的损伤减轻,各组织细胞线粒体肿胀消失。     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.     

Evidence-Based Pain Management and Palliative Care in Issue Four for 2009 of The Cochrane Library

ABSTRACT

The Cochrane Library of Systematic Reviews is published quarterly. Issue 4 for 2009 contains 4027 complete reviews, 1906 protocols for reviews in production, and 11447 one-page summaries of systematic reviews published in the general medical literature. In addition, there are citations of 600,000 randomized controlled trials, and 12,200 cited papers in the Cochrane methodology register. The health technology assessment database contains over 7500 citations. This edition of the Library contains 90 new reviews, of which 19 have potential relevance for practitioners in pain and palliative medicine.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

Molecular characterization of virulence and antimicrobial resistance profile of Shigella species isolated from children with moderate to severe diarrhea in northeastern Brazil

Molecular characterization of virulence and antimicrobial resistance profiles were determined for Shigella species isolated from children with diarrhea in Fortaleza, Brazil. Fecal specimens were collected along with socioeconomic and clinical data from children with moderate to severe diarrhea requiring emergency care. Shigella spp. were isolated by standard microbiological techniques, and we developed 4 multiplex polymerase chain reaction assays to detect 16 virulence-related genes (VRGs). Antimicrobial susceptibility tests were performed using disk diffusion assays. S. flexneri and S. sonnei were the predominant serogroups. S. flexneri was associated with low monthly incomes; more severe disease; higher number of VRGs; and presence of pic, set, and sepA genes. The SepA gene was associated with more intense abdominal pain. S. flexneri was correlated with resistance to ampicillin and chloramphenicol, whereas S. sonnei was associated with resistance to azithromycin. Strains harboring higher numbers of VRGs were associated with resistance to more antimicrobials. We highlight the correlation between presence of S. flexneri and sepA, and increased virulence and suggest a link to socioeconomic change in northeastern Brazil. Additionally, antimicrobial resistance was associated with serogroup specificity in Shigella spp. and increased bacterial VRGs.