深部脑白质缺血影像表现与MTHFR基因多态性关系的探讨

目的：探讨MTHFR的纯合突变TT型基因是否为诱发皮层下深部脑白质缺血的危险因子，并证实皮层下深部脑白质缺血影像表现与MTHFR基因C／T多态性的关系。资料与方法：选择影像表现符合皮层下深部脑白质缺血诊断标准者30例，对照组30例为影像表现正常者，运用多聚酶链反应－限制性内切酶片段长度多态性技术（PCR－RFLP）检测两组MTHFR基因多态性。结果：采用χ^2检验，得出MTHFR基因纯合突变TT型在病变组与对照组比较差异有显著性（χ^2=5.0794,P＜0．05），病变组TT型较对照组显著升高，说明MTHFR的纯合突变TT型可能是诱发深部脑白质缺血的危险因素。运用成组设计两样本比较的秩和检验，得出TT型和非TT型患者在影像表现的分级程度上有差别，携带TT型基因者影像表现分级重。结论：MTHFR纯合突变TT型基因是深部脑白质缺血发病的危险因子，且TT型基因与深部脑白质缺血的易感性和影像表现呈明显正相关。     

Behavioural and electrophysiological measures of task switching during single and mixed-task conditions

In order to understand how the brain prepares for and executes a switch in task demand, we measured reaction time (RT), accuracy, and event-related brain potentials associated with performance in single and mixed-task blocks using a cued design. Our results show that trials which repeat in a mixed-task block (repeat trials) were more demanding than trials which repeated in a single-task block, as reflected by the presence of a RT mixing cost and by the presence of a smaller target-locked positivity (P3b) on repeat trials. Within a mixed-task block, repeat and switch trials also differed, where repeat trials showed evidence of greater preparation (larger cue-locked negativity), more efficient target processing (larger target-locked P3b), and shorter RTs. In addition, the cue-locked negativity difference remained despite equating repeat and switch trials on RT, suggesting that this negativity difference is specific to the switching process. Our results are discussed in light of existing models of task switching.     

Influence of hospital volume and outcomes of adult structural heart procedures

Hospital volume is regarded amongst many in the medical community as an important quality metric. This is especially true in more complicated and less commonly performed procedures such as structural heart disease interventions. Seminal work on hospital volume relationships was done by Luft et al more than 4 decades ago, when they demonstrated that hospitals performing > 200 surgical procedures a year had 25%-41% lower mortality than those performing fewer procedures. Numerous volume-outcome studies have since been done for varied surgical procedures. An old adage "practice makes perfect" indicating superior operator and institutional experience at higher volume hospitals is believed to primarily contribute to the volume outcome relationship. Compelling evidence from a slew of recent publications has also highlighted the role of hospital volume in predicting superior post-procedural outcomes following structural heart disease interventions. These included transcatheter aortic valve repair, transcatheter mitral valve repair, septal ablation and septal myectomy for hypertrophic obstructive cardiomyopathy, left atrial appendage closure and atrial septal defect/patent foramen ovale closure. This is especially important since these structural heart interventions are relatively complex with evolving technology and a steep learning curve. The benefit was demonstrated both in lower mortality and complications as well as better economics in terms of lower length of stay and hospitalization costs seen at high volume centers. We present an overview of the available literature that underscores the importance of hospital volume in complex structural heart disease interventions.     

超顺磁性氧化铁增强MRI在肝脏局灶性病变诊断中的应用

目的探讨菲立磁增强MRI在肝脏实性占位性病变诊断中的应用价值。方法 对28例经CT、MRI或其他方式检查确诊有肝脏占位性病变者进一步行菲立磁增强 MRI检查,比较增强前后TtWI病灶及肝脏的信号强度及对比信噪比(CNR);根据增强前后病灶数量及形态进行定性诊断。结果 菲立磁强强T2WI肝脏信号强度较平扫明显下降,恶性病灶与肝脏的CNR较平扫明显提高,差异具有显著性。结论 非立磁增强TtWI明显提高肝脏实性占位性病变的检出率。     

多层螺旋CT与选择性冠状动脉造影对照研究及其临床应用

目的 评价冠状动脉多层螺旋CT血管造影(MSCTA)的临床应用价值。方法 25例患者均行冠状动脉MSCTA与选择性冠状动脉造影(SCA)，分析右冠状动脉、左冠状动脉主干、前降支和回旋支的通畅性，狭窄发生的部位和严重程度。将MSCTA与SCA结果对照，初步评价MSCTA的临床应用价值。结果 71支MSCTA显示无狭窄的冠状动脉支中，68支与SCA一致；29支显示狭窄的动脉支中，19支与SCA一致。其阴性预测值和阳性预测值分别为95．8％和65．5％；敏感度、特异度和准确度分别为86．4％、87．2％、87，0％。结论 MSCTA作为微创性检查，是评价冠状动脉病变和变异的重要的筛选手段。     

Optimization and validation of a colorimetric assay for Tetrahymena sp. survival

A colorimetric assay based on the reduction of 3-(4,5-dimethyl-2-thiazol-2-yl)-2,5-diphenyl-2h-tetrazolium bromide (MTT), for the quantification of Tetrahymena sp. survival is described. An increase in the concentration of Tetrahymena sp. cells from 0 to 1 x 10(6) cells/ml produced a linear (R(2)=0.9965) increase in the optical density (OD, 570-630 nm), and dead cells (pre-exposed to 250 mg/l formalin for 4 h) did not produce a background reading. Cells exposed to sublethal concentrations to formalin (100 mg/l or less for 4 h) recovered their growth. Using the MTT assay, we determined that Tetrahymena sp. is sensitive to formalin, chloramine-T, hydrogen peroxide, copper sulfate and NaCl. The sensitivity increased with increasing chemical concentrations and exposure time. Tetrahymena sp. was resistant to bromex and malachite green. The use of this assay in drug screening for the development of treatments for tetrahymenosis and as a bioassay to evaluate the toxicity of environmental toxicants is discussed.     

非DICOM设备标准化的实现技术

我国的现有医疗影像设备的接口种类繁杂,只是部分较先进的设备才具有标准数字接口.为了将这些设备接入PACS,需要将从现有设备中获取的图像转换为DICOM3 0格式,并赋予其DICOM标准中的某种角色,以利于实现PACS等网络的建设.本文提出了一种实现DICOM标准化的可行技术.     

益气活血法对舒张性心力衰竭大鼠心肌细胞钙稳态的影响

目的 研究不同比例益气活血药对舒张性心力衰竭(DHF)大鼠的疗效,探讨其对心肌细胞钙稳态的影响机制。方法 采用改良缩窄腹主动脉术制备压力负荷致DHF大鼠模型。将大鼠分为假手术组、模型组、益气组(黄芪3 g、党参1.5 g)、益气活血1∶1组(黄芪3 g、党参1.5 g、丹参3 g、三七1 g)、益气活血2∶1组(黄芪6 g、党参3 g、丹参3 g、三七1 g),每组20只,连续干预12周。治疗4、12周进行心功能检测,测量舒张期左室前壁厚度、舒张期左室后壁厚度、舒张期左室内径、左室射血分数和左室短轴缩短率及舒张早期跨二尖瓣血流速度(E)与舒张早期二尖瓣环运动幅度(e)比值(E/e);12周进行血流动力学检测,分别在静息状态和盐酸多巴胺负荷状态下记录左室压力下降速率、左室舒张末期压力(LVEDP)以评价左室舒张功能,记录左室压力上升速率,左室收缩压力(LVESP)以评价左室收缩功能,并记录心率及颈动脉压力;12周后处死大鼠,检测心肌细胞舒缩功能及钙转运情况,测量心肌细胞的收缩速率、舒张速率、收缩50%时间(CT50)和舒张50%时间(RT50);测定钙释放速率、钙回摄速率、钙释放50%时...     

组织谐波成像与CT扫描在急性胰腺炎诊断中的应用价值

目的 探讨组织谐波成像技术(THI)及常规二维超声(B-US)与CT扫描在急性胰腺炎超声诊断中的临床应用价值。方法 回顾性分析，应用THI技术与B-US诊断急性胰腺炎，均与手术、病理对照。结果 192例急性胰腺炎，应用THI技术，超声诊断符合率93．8％(180／192)，B-US检出率85．9％(165／192)，CT检出率97．4％(187／192)。对136例胆源性急性胰腺炎的病因，胆石症占89例，超声诊断符合率97．8％(87／89)，CT检出率85．4％(76／89)，胆道蛔虫占47例，超声诊断符合率97．9％(46／47)，CT检出率87．2％(41／47)。其中急性水肿型胰腺炎(间质性)154例，占80．2％(154／192)，急性出血坏死型胰腺炎(坏死性)38例，占19．8％(38／192)。结论 THI与B-US联合应用，可互相取长补短，互相印证，对胆源性急性胰腺炎的病因诊断，优于CT扫描，超声检查方法直接、简便、无痛、无创、迅速、可靠，对制定治疗方案与评估预后，具有重要的临床应用价值。     

External influences on curriculum design in radiography degrees

This article seeks to identify some of the documentation and legislation which must now influence those involved in curriculum design, in order that the resultant professional is fit for purpose and is a competent and safe practitioner within a modern and evolving health care setting. It attempts to explain and justify areas of academic study which are perhaps misunderstood by clinical colleagues.