超声对周围神经慢性卡压损伤引起神经形态学变化的实验研究

目的探讨周围神经慢性卡压损伤后不同时间的声像图变化,以及卡压时间与病理变化之间的关系。方法健康家兔20只,随机均分为5组。4只分离坐骨神经不进行卡压,作为对照组;16只分为4组,分离坐骨神经后,分别神经卡压2,4,6,8周,作为卡压2周组、卡压4周组、卡压6周组、卡压8周组;各组分别去除卡压后即取材行组织形态学观察和病理学检查。超声观察坐骨神经的直径、连续性、外膜边缘整齐与否及内部回声情况;诱发电位仪测定运动神经传导速度(MNCV)和感觉神经传导速度(SNCV)。结果对照组在观察时间段内未见明显改变。各卡压组随卡压时间的延长,神经卡压段及两端内径逐渐增粗,卡压两端局部形成瘤样改变,内部回声逐渐减低,线性回声连续性差,神经外膜逐渐增厚,MNCV和SNCV随着卡压时间延长而减慢。各卡压组神经卡压区域均发生不同程度的轴突肿胀和阶段性脱髓鞘改变,卡压时间越长病理变化越重。卡压2周组神经束内髓鞘轴索和神经束膜纤维出现明显水肿,余各卡压组可见髓鞘崩解,轴突变性,纤维结缔组织增生逐渐明显。各卡压组坐骨神经远端、近端直径较对照组增大,MNCV和SNCV较对照组减慢,差异均有统计学意义(P0.05)。各卡压组坐骨神经直径与MNCV和SNCV均呈负相关(r分别为-0.76和-0.69,P0.05)。结论超声可实时、准确地反映神经慢性损伤后形态的动态变化,周围神经卡压损伤程度与卡压时间成正相关,及早去除卡压有利于损伤神经再生与修复。     

周围神经卡压松解的实验研究及临床应用

目的：局围神经卡压是常见病多发病．多以手术松解来研究治疗。对此问题，我们进行了实验研究，并在此基础上选择最佳术式应用临床48例，方法：在Mackinnon所设计了的大鼠坐骨神经卡压模型的基础上，研究了神经卡压松解四种不同疗法的优劣。分组：A组仅击除卡压；B组去除卡压后用手术刀切开神经外膜；C组去除卡压后行高压氧冶疗。D组去除卡压后用手术刀切开神经外膜然后行高压氧治疗，术中不同时间（1～4周)进行电生理组织学检测，所有操作均在手术显微镜下进行．同时应用术中肌电监测技术。结果：动物实验揭示神经卡压物去除后再切开神经外膜，然后行高压氧治疗．此种方法为较理想的神经忙压松解术式。结论：术中应用肌电持续监测技术．有效地促进丁手术方法的准确性与手水操作的精确性，提高丁周围神经手术的疗效。临床应用48例病人、43例随访12～18个月．均取得了满意疗效，     

物理因子治疗周围神经卡压综合征术后的临床观察

目的：观察物理因子对周围神经卡压综合征术后神经恢复的临床效果。方法：周围神经卡压综合征术后患者124例,随机分为电刺激组（A组）、分米波组（B组）、电刺激＋分米波组（C组）和对照组（D组）各31例,均给予功能锻炼指导及相应治疗。结果：治疗3个月后,临床疗效比较,A、B及C组优良率均优于D组,C组优于A、B组（均P〈0.05）。结论：分米波及电刺激综合应用具有协同作用,能明显缩短周围神经恢复的时间。     

超声声学定量评估大鼠坐骨神经卡压程度的实验研究

目的分析不同程度卡压神经回声强度及组织病理的变化规律,寻找其相关性,为神经卡压症超声组织定征提供理论依据。方法建立大鼠坐骨神经不同程度卡压模型两组(A组,n=8;B组,n=8),C组为对照组(n=8),超声测量卡压神经的回声强度值变化,并取组织行HE染色和砂罗铬花青染色,观察其神经组织形态结构的变化情况,分析其与回声强度值变化的相关性。结果随卡压程度加重,神经组织逐渐出现较多且严重的形态学改变,髓鞘变性、脱髓鞘、纤维化及轴突碎裂。体视学检查示各组间平均光密度和积分光密度比较差异均有统计学意义(P0.05),且随卡压程度加重而降低。超声定量分析示各组神经组织声强值间比较差异有统计学意义(P0.05),组间两两比较差异亦有统计学意义,且A、B组声强值随导管内径缩小而减小。三组声强值与平均光密度相关系数分别为0.954、0.881、0.887(P0.05),与积分光密度相关系数分别为0.945、0.864、0.864(P0.05)。结论回声强度检测可定量评估不同卡压程度的神经组织,为神经卡压症的治疗提供有价值的信息。     

周围神经卡压松解的实验研究及临床应用

目的：周围神经卡压是常见病多发病，多以手术松解来研究治疗。对此问题，我们进行了实验研究，并在此基础上选择最佳术式应用临床４８例，方法：在Ｍａｃｋｉｎｎｏｎ所设计了的大鼠坐骨神经卡压模型的基础上，研究了神经卡压松解四种不同疗法的优劣。分组：Ａ组仅去除卡压；Ｂ组去除卡压后用手术刀切开神经外膜；Ｃ组去除卡压后行高压氧治疗。Ｄ组去除卡压后用手术刀切开神经外膜然后行高压氧治疗，术中不同时间（１～４周）进行电生理组织学检测，所有操作均在手术显微镜下进行，同时应用术中肌电监测技术。结果：动物实验揭示神经卡压物去除后再切开神经外膜，然后行高压氧治疗，此种方法为较理想的神经卡压松解术式，结论：术中应用肌电持续监测技术，有效地促进了手术方法的准确性与手术操作的精确性，提高了周围神经手术的疗效。临床应用４８例病人、４３例随访１２～１８个月，均取得了满意疗效     

经皮电刺激对慢性神经卡压治疗效果的实验研究

目的 观察经皮电刺激在大鼠坐骨神经慢性卡压中的应用效果。方法 用40只大白鼠采用Mackinnon所设计的大鼠坐骨神经卡压模型,在卡压20周后,分成4组进行实验：A组：不减压组;B组：减压组;C组：减压＋电刺激组;D组：仅做电刺激组。结果 C组电生理与病理检测指标明显优于其他各组。结论 神经减压＋电刺激的治疗效果理想。     

分米波对大鼠周围神经慢性卡压的作用机制

目的：探讨分米波对周围神经慢性卡压康复的作用机制。方法：选取SD大鼠90只，随机分成A（实验）、B（空白对照组）两组。制备Mackinnon坐骨神经卡压模型。A组术后第1d至术后12周，局部行分米波辐射，B组于A组治疗同时行空白对照。术后进行大体、光镜、电镜、免疫组化、轴突图像分析和神经电生理测定。结果：实验组较对照组再生有髓神经纤维数目多、髓鞘发育成熟，神经膜细胞中S-100蛋白的表达水平较高，神经传导速度快且波幅较高。结论：分米波可促进神经膜细胞增殖，提高再生神经中S-100蛋白的表达水平，有利于神经再生和功能恢复。     

应用神经阻滞方法验证臀上皮神经卡压综合征存在另一卡压点

目的 通过试验性神经阻滞的方法证实臀上皮神经卡压除了存在入臀点的卡压外，还存在椎后关节处的卡压。方法 对34例臀上皮神经卡压综合征患者进行神经阻滞以分析卡压点。首先阻滞臀上皮神经在髂嵴入臀点处，10min后患者自行评定疼痛缓解明显列为A组；余患者再次对L1-2、L2-3的患侧椎后关节外饲阻滞脊神经后支，10min后评定疼痛缓解明显列为B组；仍不明显者列为C组。记录可能造成臀上皮神经卡压的各种体征，其中小关节紊乱的体征包括棘突偏斜、条索状韧带剥离硬结、棘突侧方压痛等；入臀点处的体征包括入臀点压痛、入臀点附近皮下痛性硬结。盲法统计分析各组患者的性别、年龄、病史和体征。结果 18例患者仅阻滞臀上皮神经在髂嵴入臀点则疼痛明显缓解，提示臀上皮神经卡压点位于该点或该点以下(归为A组)。12例患者需要对椎后小关节部位阻滞后疼痛才明显缓解，证实椎后关节存在另一卡压点(归为B组)。4例患者疼痛仍无明显缓解，推测可能卡压点仍存在于椎后关节以上如椎间孔处，或者脊神经后支的阻滞不完全所至(归为C组)。A组与B组之间年龄、性别、病史无显著性差异，B组具有关节紊乱的体征较A组明显为多(P&;lt;0．01)。结论 椎后关节紊乱可以造成脊神经后支卡压，也是造成臀上皮神经卡压的因素。     

经皮电神经刺激对周围神经再生的影响

目的　探讨经皮电神经刺激 (TENS)对周围神经再生的影响。方法　将 18只健康白兔按术后取材时间的不同随机分为A、B、C 3组 ,将各组白兔双侧腓总神经切断后与同侧外膜开窗的胫神经作端侧缝合。白兔左后肢为实验侧 ,术后给予TENS ,每天 1次 ,右后肢不给予电刺激 ,作为对照侧。 3组白兔分别于术后 3、6、16周取材 ,进行大体观察、神经组织学、透射电镜和电生理检查。结果　A、B、C组白兔实验侧腓总神经有髓纤维数 ,C组实验侧运动神经传导速度、肌肉复合电位波幅均高于相应各组对照侧 (P <0 .0 5 ) ,各组白兔实验侧腓总神经髓鞘成熟程度优于对照侧。结论　TENS具有促进周围神经再生 ,提高神经侧支萌出率的作用     

不同治疗方法对坐骨神经卡压损伤大鼠疼痛阈值和电生理学变化的影响

目的：探讨坐骨神经卡压损伤后4种治疗方法对疼痛缩腿阈值和电生理指标恢复的影响。方法：将32只SD大鼠(180～220g)制备成慢性坐骨神经卡压模型(CCI模型)，随机分为4组，每组8只，1周后去卡压，即刻在损伤的神经外膜周围分别给予以下药物：对照组：生理盐水0．05mL，利多卡因组：20g／L利多卡因0．05mL，得宝松组：得宝松0．05mL，联合用药组：利多卡因0．05mL+得宝松0．05mL，分别于去卡压后即刻、给药后1，2，4，6，8周定期测定大鼠足爪的疼痛缩腿阈值，并观察损伤神经各种电生理指标及电镜的变化。结果：去卡压一至两周，各组检测指标均有恢复，去卡压后第2周，联合用药组疼痛阈值、运动神经传导速度、动作电位波幅明显优于其他3组(P&;lt;0．05)，电镜显示各组坐骨神经髓鞘板层结构均较松散，但联合用药组出现增生肥大的雪旺氏细胞；去卡压后4～8周，联合用药组各项指标的恢复较其他3组明显增快(P&;lt;0．05)，电镜显示各组均出现明显的“洋葱球”改变；联合用药组电镜变化尤为明显。结论：慢性卡压神经损伤应及早去除卡压，单纯给予利多卡因或得宝松效果欠佳，同时加局麻药有助于神经源性疼痛的缓解和功能的恢复。     

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.