Wall shear stress effects of different endodontic irrigation techniques and systems

ObjectivesThis study examined débridement efficacy as a result of wall shear stresses created by different irrigant delivery/agitation techniques in an inaccessible recess of a curved root canal model.MethodsA reusable, curved canal cavity containing a simulated canal fin was milled into mirrored titanium blocks. Calcium hydroxide (Ca(OH)₂) paste was used as debris and loaded into the canal fin. The titanium blocks were bolted together to provide a fluid-tight seal. Sodium hypochlorite was delivered at a previously-determined flow rate of 1 mL/min that produced either negligible or no irrigant extrusion pressure into the periapex for all the techniques examined. Nine irrigation delivery/agitation techniques were examined: NaviTip passive irrigation control, Max-i-Probe^® side-vented needle passive irrigation, manual dynamic agitation (MDA) using non-fitting and well-fitting gutta-percha points, EndoActivator™ sonic agitation with medium and large points, VPro™ EndoSafe™ irrigation system, VPro™ StreamClean™ continuous ultrasonic irrigation and EndoVac apical negative pressure irrigation. Débridement efficacies were analysed with Kruskal–Wallis ANOVA and Dunn's multiple comparisons tests (α = 0.05).ResultsEndoVac was the only technique that removed more than 99% calcium hydroxide debris from the canal fin at the predefined flow rate. This group was significantly different (p < 0.05) from the other groups that exhibited incomplete Ca(OH)₂ removal.ConclusionsThe ability of the EndoVac system to significantly clean more debris from a mechanically inaccessible recess of the model curved root canal may be caused by robust bubble formation during irrigant delivery, creating higher wall shear stresses by a two-phase air–liquid flow phenomenon that is well known in other industrial débridement systems.     

Analysis of time intervals related to STEMI management in 2008–2016

IntroductionA modern treatment of patients with ST segment elevation myocardial infarction (STEMI) is based on a rapid primary percutaneous coronary intervention with direct recanalization of the affected coronary artery (dPCI). The outcome of the treatment depends largely on the pre-hospital care management, which can reduce the total ischaemic time and subsequently improve patient's outlook.AimsThe principal aims of this retrospective study were to assess the development of time intervals related to the pre-hospital care and the effect of the mode of transportation to the cathlab (primary vs secondary) on these intervals in patients with acute STEMI treated by primary PCI in 2008, 2010, 2012, 2014 and 2016.MethodsWe have analysed patients with STEMI treated using PCI within 12 h of symptoms onset. In total, 1250 patients were included. To evaluate the development over the last 8 years, uni- and multivariate analyses were used. Categorical variables were analysed using chi-squared tests while continuous variables were analysed using one-way ANOVA and general linear models. The effect of the year and of mode of transportation on time intervals were studied.ResultsThe time intervals did not significantly differ among years with the exception of 2014 where the reason of the deviation was however not related to the quality of the pre-hospital care. The 120 min limit from the first medical contact to unblocking the affected artery (FMCTB) was met in more than 80% patients (80.8), the recommended limit of 90 min in 55.2% of patients. The key factor affecting the total ischaemic time was however the patients’ choice of the mode of transportation – in patients who opted for the primary route of transportation, i.e., called the ambulance, the intervals were significantly shorter (FMCTB on average by 38.2 min and total ischaemic time by 92.9 min). The principal delays were detected in the patients’ delay (103 min inpatients with primary transportation route, 131 in patients with secondary route) as well as, unfortunately, in the intervals between reporting the patients’ problem to the system and ECG-confirmed diagnosis (26 min if the patient calls ambulance vs 52 min if they present at a general practitioner or outpatient clinic) and subsequent transportation to the cathlab (60 min for primary route, 97 for secondary). The latter two should be in particular targeted and we can see a significant room for improvement here.ConclusionThe time intervals do not vary among individual years (with some exceptions). The route of transportation, which is a patient's choice, on the total ischaemic time is however a crucial and predominant factor affecting the total ischaemic time as well as individual intervals.     

基于“脾主运化”理论探讨肝细胞自噬与脂质代谢的关系＊

脾位于中焦,主运化,为气血生化之源。膏脂由脾运化水谷所生,中土得运,纳运有常,则膏脂可随血循环以濡养五脏六腑及四肢百骸;肝脏是脂质代谢重要的器官,其参与脂质消化、吸收、转运等功能,脾气健运,肝失疏泄,肝脏脂质代谢功能与"脾"运化功能相关。肝细胞自噬是维持肝脏脂质代谢稳态的关键因素之一,自噬功能正常则肝脏脂质代谢趋于平衡。本文基于脾与脂质相关性,从"脾主运化"探讨肝细胞自噬对脂质代谢的影响及机制。     

外泌体的生物学特征及其作为靶向药物载体在恶性肿 瘤的应用

肿瘤治疗过程中会出现很多严重的不良反应，如何将药物特异性导向癌细胞就成为了肿瘤治疗中亟需解决的问 题。外泌体是由细胞分泌的、纳米级别的、双层脂质的盘状囊泡结构。正常细胞与肿瘤细胞均可分泌外泌体，供体细胞分泌的 外泌体携带着蛋白质、脂质和核糖核酸（包括microRNA和lncRNA），可直接被同组织内其周围的受体细胞所吸收；同时外泌体 几乎存在于唾液、血液、尿液、脑脊髓液等所有体液中，通过体液运输被不同组织内受体细胞所吸收，为受体细胞的生长提供必 要的营养物质。肿瘤细胞中往往可对外释放出高于正常组织的外泌体，在肿瘤发展过程中外泌体对肿瘤的生长、转移和血管 生成起到重要的作用；同时癌细胞所分泌的外泌体中有着可用来区别与其他细胞外泌体不同的特征性分子，可作为肿瘤临床 诊断的分子标志物，也可作为肿瘤分级、精准治疗及预后评估的重要依据。鉴于此，本文收集国外内相关研究资料，对外泌体 的生物学特征进行总结，并综述了其在临床肿瘤诊断、治疗中的作用及应用潜力，并对外泌体进一步的发展方向进行展望，以 期能为外泌体在临床肿瘤精准治疗中的应用提供理论支持。     

右室起搏电极参数随诊及其对心功能的影响

目的通过比较右室间隔部起搏和右室心尖部起搏电极参数和心功能的变化趋势，选择更为有利的起搏方式。方法选取心尖部起搏21例和间隔部起搏21例，术时、12个月、24个月随诊，分别作心脏彩色多普勒超声检查，记录左室舒张末期内径（LVEDD）、左室射血分数（LVEF）、起搏心电图测量Ⅱ导联QRS波时限、抽血查氨基末端脑钠肽前体（NT-proBNP）、起搏器程控仪记录阈值、阻抗、R波感知进行比较。结果间隔部组比心尖部组QRS时限和电极阻抗小，随起搏时间延长QRS时限、NT-proBNP、LVEDD增加、LVEF（％）下降，心尖部组表现较为明显。结论间隔部起搏QRS波较窄，LVEF（％）下降缓慢、LVEDD（mm）和NT-proBNP（pg／m1）升高缓慢，与心尖部起搏比较，心室同步性好、可延缓心功能减退，是右室起搏较好的选择部位。