血管回声跟踪技术检测终末期肾病患者颈动脉弹性功能

目的探讨回声跟踪（ET）技术对终末期肾病（ESRD）患者颈动脉弹性的检测及其意义。方法应用ET检测20例ESRD患者颈动脉弹性指标参数（β）、压力应变弹性正数（Ep）、动脉顺应性（AC）、脉搏波放大指数（AI）及单点脉搏波传递速度（PWVβ），并与正常人进行比较。20例患者中合并及不合并高血压者各占10例，比较ESRD合并及不合并高血压组与正常人的颈动脉弹性有无差异。结果无论是否合并高血压，ESRD组的β、Ep及PWVβ较正常人高，AC及AI无差异。结论ESRD患者不论是否合并高血压其颈动脉弹性功能都会减低，ET技术能够敏感地检测这一改变，更多的研究需要进一步进行。     

血管回声跟踪技术对高血压患者颈动脉弹性功能的检测

目的:探讨血管回声跟踪技术(echo tracking,ET)检测高血压患者颈动脉弹性功能指标β、Ep、AC、AI、PWVβ的改变及其意义.资料及方法:应用ET 检测高血压患者共58例(平均年龄62.5岁)的颈动脉的弹性指标,包括僵硬度参数β、压力应变弹性系数Ep、动脉顺应性AC、脉搏波放大指数AI及脉搏波传递速度PWVβ.58例次中,有17例为高血压控制者,41例为高血压未控制者;58例中有33例为高血压不合并其他疾病,25例为高血压合并其他疾病.比较高血压组合并及不合并其他疾病组与147例正常人颈动脉弹性有无差异;高血压控制组与未控制组颈动脉弹性有无差异.并用SAS 6.12做统计分析.结果:高血压患者无论是否合并其他疾病其颈动脉的β、Eρ、AC及PWVβ与正常人均有差异,AI无差异;高血压控制组与未控制组颈动脉的AI及PWVβ有差异,β、Eρ及AC无差异.结论:ET技术能够较敏感的检测高血压的颈动脉弹性功能;高血压患者无论是否合并其他疾病其颈动脉弹性功能都减低,血压比其他疾病对弹性影响更加明显;控制血压可部分改善颈动脉弹性功能指标.     

血管回声跟踪技术评价甲状腺功能减退症颈动脉弹性的临床研究

目的 探讨血管回声跟踪技术(echo-tracking,ET)对甲状腺功能减退症(甲减)患者颈动脉壁弹性的诊断价值.方法 应用ET技术对32例甲减患者和30例正常人右侧颈总动脉进行超声检测,评估颈动脉弹性参数指标,包括硬化参数(β)、血管压力应变弹性系数(Eρ)、血管顺应性(AC)、脉搏波增大指数(AI)及脉搏波传导速度(PWVβ),将两组参数进行比较.结果 与对照组相比,甲减组β、Eρ和PWVβ明显升高,AC显著减低(P＜0.05),AI无显著性差异(P＞0.05).β、Eρ、PWVβ值的升高可能继发于甲状腺激素水平的降低.结论甲减患者颈动脉弹性明显低于正常对照组,ET技术为甲减患者颈动脉的弹性检测提供了一种快捷、无创的早期评价方法 .     

高血压患者治疗前后颈动脉弹性功能的超声定量检测

目的探讨血管回声跟踪技术(ET)检测高血压患者治疗前后颈动脉弹性功能改变及其意义。方法应用ET检测高血压患者共20例,分别在用尼莫地平和/或卡托普利治疗前及治疗3个月后检测颈动脉的弹性指标僵硬度参数(β)、压力应变弹性系数(Ep)、动脉顺应性(AC)、脉搏波放大指数(AI)及脉搏波传递速度(PWVβ),并与20例对照组进行比较。结果高血压患者治疗前与对照组相比,β、Eρ、AC及PWVβ有明显差异,治疗前后颈动脉的弹性指标无明显改变。结论本组高血压患者治疗3个月后,颈动脉弹性指标无明显改善,ET技术能定量反映高血压治疗前后颈动脉弹性功能状况。     

血管回声跟踪技术对颈动脉单点脉搏波传导速度的检测及其意义

目的探讨血管回声跟踪（ET）技术对颈动脉单点脉搏波传导速度（PWVβ）的检测及其临床意义。 方法检测20～、30～、40～、50～及≥60岁5个不同年龄组健康成人145例、高血压48例、糖尿病26例、终末期肾病20例的颈动脉PWVβ；比较性别间PWVβ差异；比较各组间PWVβ值与其同龄人传统两点PWV的差异；比较上述疾病与其同龄正常人的PWVβ的差异。 结果上述5组的颈动脉PWVβ分别为4．6±0．6、5．9±1．1、6．1±1．2、6．7±1．2及（7．6±1．3）m／s；各组PWVβ均较传统的PWV值低，但二者相关性良好；不同性别间PWVβ无差异；高血压及终末期肾病患者PWVβ增高，而糖尿病患者PWVβ与同龄正常人无明显差异。 结论PWVβ随着年龄的增高而增高且与传统的PWV相关良好；PWVβ能较好地反映不同年龄及疾病的动脉弹性状态；用超声ET技术检测的PWVβ能较敏感地反映这些变化。     

血管回声跟踪技术诊断2型糖尿病患者动脉早期硬化

目的 探讨血管回声跟踪(echo-tracking,ET)技术对2型糖尿病患者早期动脉硬化的应用价值.方法 在ET模式下,采集30例正常人和54例2型糖尿病患者的股动脉的二维超声图像,测量双侧股动脉内-中膜厚度(IMT).应用ET技术检测弹性指标β、Eρ、AC、AI及PWVβ.按照股动脉IMT是否＜1.0 mm将糖尿病患者分为A(IMT＜1.0 mm) 组和B(IMT≥1.0 mm) 组.结果 A组及B组股动脉弹性指标β、Eρ、PWVβ均较对照组显著增高(P<0.05),AC值显著降低(P<0.05).B组股动脉弹性指标β、Eρ、PWVβ较A组也显著增高,统计学有显著性差异(P<0.05).结论 糖尿病患者存在动脉硬化的病理改变,而且在形态学变化之前就有动脉弹性的减低.ET技术可以在动脉粥样硬化的形态学改变出现之前早期发现动脉硬化.     

血管回声跟踪技术对2型糖尿病患者下肢血管弹性功能的检测

目的 探讨血管回声跟踪技术(echo-racking,ET)对2型糖尿病患者下肢血管病变的诊断价值.方法 筛选30例正常人和68例2型糖尿病患者,在ET模式下采集股总动脉、腘动脉的二维超声图像,应用ET技术检测其动脉弹性指标:僵硬度指数(β),血管压力-应变弹性系数(Eρ),顺应性(AC),增大指数(AI),脉搏波传导速度(PWVβ).结果 糖尿病组股总动脉、腘动脉的β、Eρ、PWVβ较对照组显著增高(P<0.05),AC值显著降低(P<0.05),AI值与对照组相比差异无统计学意义(P>0.05).结论 糖尿病患者的股动脉存在动脉硬化,腘动脉作为肌性动脉也存在动脉硬化,且与弹性大动脉股动脉改变一致,有良好的相关性.ET技术为2型糖尿病患者下肢动脉的弹性检测提供了一种快速、无创的评价方法 .     

血管回声跟踪技术评价不同血压水平对颈动脉内皮功能的影响

目的:应用血管回声跟踪(ET)技术定量评价不同血压水平对颈动脉内皮功能的影响。方法:选择高血压组(HP组)50例、正常高值血压组(HN组)30例和正常血压组(NP组)30例,常规二维超声测量颈动脉内膜中层厚度(IMT)和ET技术检测颈动脉弹性参数(Eρ、β、AC、AI、PWVβ),并进行统计学分析。结果:3组研究对象均合并较多的心血管危险因素,HN组较NP组排除混杂因素前IMT、Eρ、PWVβ差异值有显著性而排除混杂因素后仅PWVβ值差异显著(P=0.04),HP组较NP、HN组于排除混杂因素前后各硬化参数差异均显著。结论:血压升高与血管内皮功能损伤密切相关,但正常高值血压本身对颈动脉弹性无明显影响,其所合并的危险因素在动脉硬化及血压升高过程中起到重要作用;在高血压早期,即使颈动脉未发生明显病理形态学改变,血压已成为血管内皮功能损伤的独立危险因素。     

血管回声跟踪技术对颈动脉脉搏波放大指数的检测及其意义

目的探讨血管回声跟踪技术(ET)对颈动脉脉搏波放大指数(AI)的检测及其临床意义。方法应用ET技术检测不同年龄正常人145例、高血压患者48例、糖尿病患者26例、终末期肾病20例的AI;正常健康人分为5个年龄组:20~29岁23人,30~39岁22人,40~49岁35人,50~59岁34人,≥60岁31人。比较不同性别及不同年龄组间的AI值有无差异;比较本组各年龄组ET检测的AI与其他方法测得同龄人的AI;比较上述各疾病与同龄正常人AI的差异。用SAS6.12做统计分析。结果AI无性别差异但有年龄差异:在上述5个年龄组的AI测值分别为5.2、7.6、12.8、16.2和20.8;各年龄组ET检测的AI与其他作者其他方法测定的AI相关性良好;高血压、糖尿病及终末期肾病患者的AI均较其同龄人增高。结论ET技术中的脉搏波放大指数AI能较好地反映颈动脉弹性情况,随着年龄增高,高血压、糖尿病及终末期肾病患者的AI明显增高。     

糖尿病患者颈动脉弹性功能与血清MMP-9水平的相关性研究

目的探讨糖尿病患者颈动脉弹性指标与血清基质金属蛋白酶-9(MMP-9)水平的相关性。方法选取糖尿病颈动脉内膜未见明显改变患者31例(内膜正常组)、糖尿病颈动脉内膜增厚及斑块形成患者40例(内膜改变组)及健康志愿者30例(正常对照组),应用酶联免疫吸附试验检测各组血清MMP-9水平,血管回声跟踪(ET)技术检测并比较各组颈动脉僵硬度(β)、压力弹性应变系数(Eρ)、顺应性(AC)、增大指数(AI)及脉搏波传导速度(PWVβ),分析糖尿病患者血清MMP-9水平与颈动脉弹性指标的相关性。结果与正常对照组比较,内膜正常组Eρ、AI、PWVβ及MMP-9水平均增高,AC降低,差异均有统计学意义(均P0.05);内膜改变组β、Eρ、AI、PWVβ及MMP-9水平均增高,AC降低,差异均具有统计学意义(均P0.05)。与内膜正常组比较,内膜改变组β、Eρ、PWVβ及MMP-9水平均增高,AC降低,差异均有统计学意义(均P0.05)。内膜正常组血清MMP-9水平与Eρ、AC、PWVβ相关(r=0.375、-0.716、0.405,均P0.05);内膜改变组血清MMP-9水平与Eρ、β、AC相关(r=0.616、0.381、-0.484,均P0.05)。结论糖尿病患者颈动脉弹性指标与血清MMP-9水平相关,可作为糖尿病患者早期发现动脉粥样硬化病变的敏感指标。     

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.