心肌梗死大鼠心肌细胞凋亡及磷酸肌酸的干预

目的:缺血引起的心肌能量供应不足是心肌细胞凋亡主要的因素之一,观察补充外源性能量磷酸肌酸对缺血心肌细胞凋亡和心功能的影响。方法:实验于2003-04/06在解放军总医院老年心血管病研究所实验室完成。选用SD大鼠50只,按随机数字表法分为3组:①磷酸肌酸组19只,结扎左冠状动脉制作心肌梗死模型,结扎前30min按200mg/kg的剂量腹腔注射磷酸肌酸1次。②缺血对照组21只,心肌缺血方法同磷酸肌酸组,结扎前30min腹腔注射相同体积的50g/L葡萄糖注射液1次。③正常对照组10只,仅在冠状动脉下穿线,不结扎冠状动脉,其余同缺血对照组。结扎冠状动脉6h后,取各组大鼠心脏标本做石蜡切片,缺口末端标记法染色,高倍镜下计数心肌细胞凋亡指数,凋亡指数=凋亡心肌细胞数/心肌细胞总数;取心脏标本前,测左心室收缩压、舒张末压和压力变化速度,并进行组间比较。结果:磷酸肌酸组大鼠造模时死亡9只;缺血对照组造模时死亡10只,造模成功后6h内死亡1只,进入结果分析共30只大鼠,每组10只。①缺血对照组大鼠的左心室舒张末压显著高于正常对照组[(13.9±5.3vs.2.8±3.2)mmHg(P<0.01)],左心室压力变化速度显著低于正常对照组[(705.8±111.7vs.1141.7±94.5)mmHg/s(P<0.01)];磷酸肌酸组大鼠的左心室舒张末压显著低于缺血对照组[(8.9±3.5)mmHg(P<0.05)];左心室压力变化速度显著高于缺血对照组[(841.5±76.1)mmHg/s(P<0.01)];左心室收缩压与缺血对照组差异无显著性意义(P>0.05)。②磷酸肌酸组大鼠的心肌细胞凋亡指数显著低于缺血对照组(0.203±0.054vs.0.278±0.052,P=0.006)。结论:补充外源性能量磷酸肌酸可以减少缺血后心肌细胞凋亡,并改善心功能,磷酸肌酸抑制缺血心肌细胞凋亡可能是改善心肌梗死后心功能的主要作用途径之一。     

Blood transfusion practices in military medicine

Background: This observational study was conducted in a small, 45 bed border static hospital, located in a field area, where no blood bank facilities were available. The present study was conducted to elucidate the blood transfusion practices of this hospital.     

Health services utilization by school going Omani adolescents and youths with DSM IV mental disorders and barriers to service use

Background  

Recent corpus of research suggests that psychiatric disorders amongst adolescents and youths are an emerging global challenge, but there is paucity of studies exploring health services utilization by this age group in Arab region.     

Numerical analysis of the flow characteristics of rotary blood pump

Thrombus formation and hemolysis have been linked to the dynamics of blood flow in rotary blood pumps and ventricular assist devices. Hemolysis occurs as the blood passes through the pump housing, and thrombi develop in stagnation and low-velocity regions. The predicted velocities, pressure, and turbulence quantities from the numerical simulation are used to identify regions of high shear stress and internal recirculation. A nimerical technique is described that simulates the hydrodynamic characteristics of a rotary blood pump with a flow rate of 6 l/min at a rotational speed of 3000 RPM. A computational fluid dynamics (CFD) code, CFX 4, is used to solve the time-dependent incompressible Navier-Stokes equations using a transient finite volume method and three-dimensional structured grids. The simulation utilized the sliding mesh capabilities of this numerical code to model the rotating impeller and examine the effect of blade shape on the hydrodynamic performance of the blood pump in terms of pressure rise, flow rates, and energy losses. The first impeller model has six straight channels; the second impeller has six backward-curved channels. The results for two impeller configurations are presented and discussed. The curvedpump design resulted in higher pressure rise and maximum shear stresses than the straight-channel one. In general the paper demonstrates that CFD is an essential numerical tool for optimizing pump performance with the aim of reducing trauma to the blood cells.     

RETRACTED ARTICLE: Microwave sterilization of bovine pericardium for heart valve applications

It is widely recognised that the bioprosthetic valves widely used for heart valve replacements have some drawbacks, for example tearing and occurrence of infections, which can be attributed to the fixation and sterilization techniques currently available. These techniques adversely affect the physical properties, functionality, and lifespan of the leaflets. In the work discussed in this paper we examined a novel procedure of using high-frequency microwaves to fix and disinfect the pericardium, without causing any harmful affects. The test bacteria used were Escherichia coli and Staphylococcus aureus. The pericardium was exposed to microwaves at a frequency of 18 GHz for three consecutive replicates. The findings indicated that there was almost complete inactivation of the bacteria on the biomaterial without compromising the biocompatibility, which was studied using ovine fibroblasts. An effective fixation and sterilization procedure, that is quick and has no adverse effects is presented and discussed.     

Social and Self-Reflective Use of a Web-Based Personally Controlled Health Management System

Background

Personally controlled health management systems (PCHMSs) contain a bundle of features to help patients and consumers manage their health. However, it is unclear how consumers actually use a PCHMS in their everyday settings.

Objective

To conduct an empirical analysis of how consumers used the social (forum and poll) and self-reflective (diary and personal health record [PHR]) features of a Web-based PCHMS designed to support their physical and emotional well-being.

Methods

A single-group pre/post-test online prospective study was conducted to measure use of a Web-based PCHMS for physical and emotional well-being needs during a university academic semester. The PCHMS integrated an untethered PHR with social forums, polls, a diary, and online messaging links with a health service provider. Well-being journeys additionally provided information to encourage engagement with clinicians and health services. A total of 1985 students and staff aged 18 and above with access to the Internet were recruited online, of which 709 were eligible for analysis. Participants’ self-reported well-being, health status, health service utilization, and help-seeking behaviors were compared using chi-square, McNemar’s test, and Student’s t test. Social networks were constructed to examine the online forum communication patterns among consumers and clinicians.

Results

The two PCHMS features that were used most frequently and considered most useful and engaging were the social features (ie, the poll and forum). More than 30% (213/709) of participants who sought well-being assistance during the study indicated that other people had influenced their decision to seek help (54.4%, 386/709 sought assistance for physical well-being; 31.7%, 225/709 for emotional well-being). Although the prevalence of using a self-reflective feature (diary or PHR) was not as high (diary: 8.6%, 61/709; PHR: 15.0%, 106/709), the proportion of participants who visited a health care professional during the study was more than 20% greater in the group that did use a self-reflective feature (diary: P=.03; PHR: P<.001).

Conclusions

There was variation in the degree to which consumers used social and self-reflective PCHMS features but both were significantly associated with increased help-seeking behaviors and health service utilization. A PCHMS should combine both self-reflective as well as socially driven components to most effectively influence consumers’ help-seeking behaviors.     

Relationship between gastric cancer and precancerous lesions

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