多普勒超声评价维生素C和维生素E对高血压血管内皮舒张功能的影响

目的应用超声技术观察维生素C,维生素E对高血压患者肱动脉内皮依赖性舒张功能的影响。方法研究对象包括20例高血压患者和20例正常人分别服用维生素C、维生素E12个月前后,应用高分辩力超声测定静息状态下,反应性充血后,舌下含服硝酸甘油后的肱动脉内径,并计算反应性充血和硝酸甘油诱发的内径百分变化率。结果反应性充血前后肱动脉内径百分变化率,高血压组明显低于正常组(P<0.001),硝酸甘油诱发的肱动脉内径百分变化率高血压组和正常组无显著差异。服用维生素C、维生素E12个月后,高血压患者反应性充血前后肱动脉内径百分变化率明显高于治疗前(P<0.001)。但硝酸甘油诱发的肱动脉内径百分变化率无明显变化。结论服用维生素C、维生素E可改善高血压患者受损的内皮依赖性血管舒张功能。     

高频超声无创检测肾性高血压患者血管内皮功能的研究

目的评价肾性高血压患者血管内皮功能是否损害以及损害程度与肾功能的关系,以探讨高频超声检测肾性高血压患者血管内皮功能的临床价值。方法研究对象60例,分为4组。Ⅰ组：15例正常对照组;Ⅱ组：15例单纯肾性高血压组;Ⅲ组：15例氮质血症期肾性高血压组;Ⅳ组：15例尿毒症期肾性高血压组。各组分别于反应性充血前后及舌下含服硝酸甘油前后,应用高频超声检测肱动脉内径变化率,以此评价肾性高血压患者血管内皮功能是否受损以及损害程度与肾功能的关系。结果与正常对照组（Ⅰ组）相比,单纯肾性高血压组（Ⅱ组）内皮依赖性舒张功能已受损（P〈0.05）,而内皮非依赖性舒张功能无明显变化（P〉0.05）。肾性高血压患者（Ⅱ组,Ⅲ组,Ⅳ组）反应性充血引起肱动脉内径变化百分数,三组比较有显著性差异（P〈0.05）。含服硝酸甘油后肱动脉内径变化百分数,三组间比较无明显差异（P〉0.05）。结论高分辨力超声可以早期检测肾性高血压患者血管内皮功能的改变;肾性高血压患者在肾功能损害之前已存在血管内皮功能异常;肾性高血压合并肾功能不全,且肾功能不全各期内皮功能受血压影响均衡时,血管内皮功能损害随肾功能损害加重而严重;高分辨力超声检测肾性高血压患者血管内皮舒张功能无创、简单、准确,对临床具有重要的应用价值。     

原发性高血压患者血管内皮功能的超声检测

目的探讨高频超声在原发性高血压病患者血管内皮细胞功能评价中的应用价值.方法选择52例原发性高血压病(以下简称高血压)患者及无心血管疾病的对照组20名,将高血压患者按不同程度分为2组,Ⅰ组28例为高血压1级,Ⅱ组24例为高血压2～3级.所有患者排除糖尿病、肝肾疾病、血液系统疾病.使用Diasonics VMS彩色多普勒超声诊断仪,探头选用10 MHz线阵探头,检测肱动脉内径在反应性充血后及舌下含服硝酸甘油后的变化,并计算出内径变化率.使用SAS 6.12统计软件处理、分析数据.各组数据均以平均数±标准差表示,3组间比较用方差检验,性别构成比较用x2检验,P＜0.05视为有显著性差异.结果加压释放后高血压组肱动脉内径变化百分率低于对照组(P＜0.05),而高血压Ⅰ组和Ⅱ组之间比较无显著性差异.含服硝酸甘油后高血压Ⅱ组肱动脉内径变化百分率低于对照组和高血压Ⅰ组(P＜0.05),而高血压Ⅰ组与对照组之间比较无显著性差异.结论高血压患者内皮依赖性血管舒张功能受损,另外随着血压水平的升高,非内皮依赖性血管舒张功能亦有损伤,这可能是因为内皮损伤导致血管平滑肌细胞增生,血管壁弹性降低及血流阻力加大,易发生血栓形成,最终导致血管平滑肌细胞对血管活性物质的反应降低的结果.应用高分辨率超声能够准确、无创评价外周血管的内皮功能,对指导治疗、预防及控制疾病的发生发展具有重要的应用价值.     

超声无创性评价高血压与血管内皮依赖性舒张功能的相关性研究

目的 探讨高血压与血管内皮依赖性舒张功能的关系。方法 采用高分辨力超声无创性检测血管内皮依赖性舒张功能的方法比较收缩期和舒张期高血压(SDH)与正常血压组血流介导性舒张(FMD)与反应性充血的血管内皮依赖性舒张功能。结果 SDH组与对照组相比FMD和与反应性充血后肱动脉血流量的变化未见明显差异，无统计学显著性差异。结论 肱动脉超声测量血流介导的血管扩张是评价内皮功能的一项有前途的技术，但目前还不能说是评价内皮功能的良好方法。     

高频超声评价糖化血红蛋白对糖尿病患者血管内皮功能的影响

目的利用高频超声观测糖尿病患者血管内皮细胞功能及糖化血红蛋白对血管内皮功能的影响.方法将45例2型糖尿病患者按糖化血红蛋白的水平分为两组,Ⅰ组24例,糖化血红蛋白测值为静息状态下6%～8%,Ⅱ组21例,糖化血红蛋白测值为静息状态下8%以上.应用高频超声检测糖尿病患者及20例正常对照者的肱动脉在测值为静息状态下反应性充血后及舌下含服硝酸甘油后的内径变化.结果糖尿病组肱动脉反应性充血前后的内径变化率明显低于对照组(P＜0.05),同时Ⅱ组明显低于Ⅰ组.含硝酸甘油后的肱动脉内径变化率,糖尿病组与对照组无明显差异(P＞0.05).结论糖尿病患者内皮依赖性血管舒张功能受损,糖化血红蛋白对内皮功能有一定的影响.应用高分辨力超声能够准确、无创地评价外周血管的内皮功能.     

高血压病人中血管内皮功能与左室重量指数的关系

目的探讨高血压病人血管内皮依赖性舒张功能与左室重量指数的关系.方法高分辨力血管超声无创性检测血管内皮依赖性舒张功能:包括血流介导性舒张(FMD%即反应性充血后内径变化与静息内径比值)及反应性充血(反应性充血最大血流量与静息血流量比值);心脏超声测量舒张末期室间隔、左室后壁厚度及左室内径,计算左室重量指数(LVMI).结果高血压组FMD%和反应性充血均低于对照组,但无统计学差异;高血压组的LVMI显著高于对照组;高血压伴心室肥厚组FMD%及反应性充血低于非肥厚组,但无统计学差异;相关分析显示血管内皮依赖性舒张功能与LVMI临界相关.结论血管内皮依赖性舒张功能与LVMI在高血压病生理机制上可能存在某种联系,但需更加合理的研究方法进一步考证.     

高频超声评价系统性红斑狼疮患者肱动脉内皮功能

目的应用高频超声测量系统性红斑狼疮(SLE)患者反应性充血前后肱动脉内径的百分变化率评价肱动脉内皮功能。方法研究对象包括36例系统性红斑狼疮患者(依病程分为SLE1组、SLE2组)和18例健康对照者。应用高频超声测量静息状态下、反应性充血后、舌下含服硝酸甘油后的肱动脉内径,并计算反应性充血和硝酸甘油诱发的内径百分变化率及二者之比。结果SLE1组反应性充血诱发的肱动脉内径百分变化率显著低于对照组(P<0.05);SLE2组反应性充血诱发的肱动脉内径百分变化率显著低于对照组(P<0.001);SLE2组反应性充血诱发的肱动脉内径百分变化率显著低于SLE1组(P<0.05)。SLE2组含服硝酸甘油后的肱动脉内径百分变化率显著低于对照组(P<0.05)。SLE1组EDV/EIV显著低于对照组(P=0.001);SLE2组内皮依赖性舒张(EDV)与非内皮依赖性舒张(EIV)之比(EDV/EIV)显著低于对照组(P<0.001);SLE2组EDV/EIV显著低于SLE1组(P<0.05)。结论系统性红斑狼疮患者肱动脉内皮功能减低,EIV功能亦会发生改变。EDV与EIV之比(EDV/EIV)比单纯的用反应性充血诱发的肱动脉内径百分变化率更能反映其内皮功能状态。     

代谢综合征患者血管内皮舒张功能的超声检测

目的探讨高分辨力超声在代谢综合征患者血管内皮功能评价中的价值。方法选择42例代谢综合征患者(MS)及正常对照组20例。MS患者根据有无颈动脉斑块分为两组,Ⅰ组(无斑块)23例,Ⅱ组(有斑块)19例。应用Celermajer的方法,通过超声检测肱动脉反应性充血及舌下含服0.5mg硝酸甘油后肱动脉内径变化来评价血管内皮功能。同时记录颈动脉内中膜(IMT)厚度,观察有无斑块形成。结果MS组与对照组之间反应性充血后血管内径变化率均有显著性差异(P<0.01)。MS斑块组与对照组之间含服硝酸甘油后血管内径变化率有显著性差异(P<0.01)。MS斑块组与对照组之间颈动脉内中膜厚度差异有显著性(P<0.01),而MS无斑块组与对照组之间差异无显著性(P>0.05)。单元线性回归分析显示反应性充血后血管内径变化率与患者的年龄、收缩压、舒张压、甘油三脂、血糖、体质指数均呈负相关。结论代谢综合征患者存在血管内皮依赖性舒张功能损伤,颈动脉斑块组非血管内皮舒张功能亦有损害。     

原发性高血压患者肱动脉内皮功能与致动脉粥样硬化危险因素的相关性

目的：观察原发性高血压患者血液内皮素、同型半胱氨酸、低密度脂蛋白胆固醇的水平,探讨这些危险因素之间相关性及相关程度,同时关注这些危险因素与超声心动图检测的反应性充血肱动脉内径变化率之间的关系.方法：①选择2003-10/2004-04在徐州医学院附属医院心内科住院的患者56例,男40例,女16例.所有病例依据血压水平分为2组：高血压组38例,男28例,女10例;血压正常组18例,男12例,女6例.其中高血压组据冠状动脉造影结果分为2组：单纯高血压组20例和高血压合并冠心病组18例.纳入对象均了解实验目的,并愿意配合.②测定患者血压,超声心动图测量肱动脉内皮功能.计算反应性充血肱动脉内径变化率[（血流介导的肱动脉内径-安静时肱动脉内径）/安静时肱动脉内径&;#215;100%],以反应性充血肱动脉内径变化率数值大小判断肱动脉内皮功能.采用免疫法测定患者血浆同型半胱氨酸水平,采用放射免疫学法测定患者血浆内皮素1水平,采用全自动生化仪测定患者血清低密度脂蛋白胆固醇水平.③计量资料差异比较采用t检验,数据间相关性分析采用直线相关分析,多因素相关分析采用Logistic回归分析.结果：高血压患者38例,血压正常患者18例均进入结果分析.①高血压组、高血压合并冠心病组、单纯高血压组患者血浆内皮素和同型半胱氨酸水平及血清低密度脂蛋白胆固醇明显高于血压正常组（P＜0.05～0.01）,而反应性充血肱动脉内径变化率明显低于血压正常组（P＜0.05～0.01）.单纯高血压组患者血浆内皮素和同型半胱氨酸水平明显低于高血压合并冠心病组（P＜0.01）,反应性充血肱动脉内径变化率明显高于高血压合并冠心病组（P＜0.01）.②高血压组患者血浆内皮素与同型半胱氨酸呈正相关（r=0.676,P＜0.01）;内皮素与反应性充血肱动脉内径变化率呈显著负相关（r=-0.636,P＜0.01）;同型半胱氨酸与低密度脂蛋白胆固醇、反应性充血肱动脉内径变化率呈显著负相关（r=-0.378,-0.591,P＜0.05,0.01）.内皮素与低密度脂蛋白胆固醇和反应性充血肱动脉内径变化率之间无相关性.③内皮素、同型半胱氨酸、低密度脂蛋白胆固醇是高血压致动脉粥样硬化的危险因素（OR=12.341,12.489,P=0.018,0.013）,高血压致动脉粥样硬化危险因素中以内皮素作用最强,其次是低密度脂蛋白胆固醇.结论：①高血压患者血浆中内皮素和同型半胱氨酸水平及血清低密度脂蛋白胆固醇水平明显异常,内皮功能障碍,而高血压合并冠心病者上述损害更为明显.②内皮素与同型半胱氨酸最终通过共同途径损伤血管内皮细胞,内皮功能失调,反应性充血肱动脉内径变化率下降.内皮素与低密度脂蛋白胆固醇是动脉粥样硬化的两个独立的危险因素.     

超声对高血压病患者血管内皮功能的研究

目的：用高分辨率超声测定高血压患肱动脉血管的内皮依赖性舒张反应。评价高血压患的血管内皮功能；方法：研究对象包括49例高血压患和22例正常对照组。所有对象均进行了肱动脉充气加压前后血管内径变化。血管直径和血流速度变化的检测情况，用以评价肱动脉的内皮依赖性血管扩张反应。结果：高血压患肱动脉加压前后的血管直径和血流速度变化百分比明显小于正常对照组；结论：高血压患存在着血管内皮功能的下降；多普勒超声评价血管内皮功能是一种简便准确的方法。     

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.     

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.     

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.