电磁脉冲辐射对小鼠生精细胞能量代谢的影响

目的探讨电磁脉冲(EMP)辐射对小鼠生精细胞能量代谢的影响. 方法 6～8周龄二级雄性昆明小鼠114只,随机分为辐射组和对照组.辐射组小鼠分别接受8×103 V/m,2×104 V/m和6×104 V/m EMP全身重复照射5次,于照射后6 h,1 d,3 d,7 d,14 d和28 d,检测睾丸组织乳酸脱氢酶(LDH)、琥珀酸脱氢酶(SDH)、谷氨酸脱氢酶(GDH)和山梨醇脱氢酶(SODH)活性,外周血红细胞及其参数、血红蛋白浓度,同时观察睾丸组织的病理变化. 结果 3种场强的EMP照射后28 d内,各级生精细胞水肿、坏死和脱落,精子减少或缺失,间质水肿,蛋白水肿液积聚,毛细血管充血、出血;4种酶的活性在照射后14 d内与对照组比较均有不同程度降低,尤其在照射后7 d内显著降低(P<0.05或P<0.01),8×103 V/m 和2×104 V/m EMP照射后,28 d内大多数时间点的红细胞数、红细胞压积及血红蛋白浓度明显增加,6×104 V/m EMP照射后28 d,红细胞数、红细胞压积及血红蛋白浓度显著增加(P<0.05或P<0.01). 结论睾丸生精细胞的缺血、缺氧及能量代谢障碍,可能在EMP照射所致的生精细胞损伤过程中发挥重要作用.     

电磁脉冲对海马神经元的损伤效应及其对［Ca2+］i的影响

目的观察电磁脉冲(EMP)对海马神经元的损伤效应及其对[Ca2+]i的影响,以深入探讨EMP致脑损伤的机制. 方法 EMP辐射条件为6×104V/m,脉冲上升时间为20 ns,脉宽为30 μs,频率为2.5脉冲/min,作用2 min.原代培养的海马神经元经EMP辐射后,采用MTT法对细胞活力进行测定;FACS法检测细胞凋亡和坏死;Fluo-3-AM荧光探针负载、激光共聚焦显微镜扫描测定神经元胞内游离钙离子浓度,即[Ca2+]i. 结果细胞被EMP辐射后0～6 h活力明显下降(P<0.05),12 h开始回升,24 h基本接近正常水平;EMP辐射后0～12 h细胞凋亡率显著升高,坏死也有增加;EMP辐射后即刻引起神经元内的Ca2+荧光强度明显增加. 结论 EMP致海马神经元活力下降、凋亡增加、胞内钙超载.     

电磁脉冲辐射对原癌基因c-fos调控区的影响

目的　通过研究电磁脉冲 (electromagneticpulse ,EMP)辐射对原癌基因c fos调控区域的影响 ,探讨其诱导细胞功能改变的机制。方法　构建c fos启动区氯霉素乙酰化转移酶 (chloramphenicolacetyl transferase,CAT) ,然后转染HeLa癌细胞株 ,高场强EMP模拟源 (有界波模拟源 )辐射细胞 ,EMP场强为6× 10 4V/m ,脉冲上升时间为 2 0ns ,脉宽为 3 0 μs ,频率为 2 .5个脉冲 /min ,辐射 2min ,处理后 2 0min时观察细胞中CAT的活性。结果　EMP辐射转染的细胞后 2 0min ,转染了P50 0 ( -711～ -2 2 3bp)和P2 50 ( -3 62～-10 0 )的Hela细胞其CAT活性明显高于对照水平的活性 (P <0 .0 1)。结论　EMP辐射可引起c fos基因调控区的 -3 62～ -2 2 5明显改变。     

微波辐射对大鼠海马神经元的损伤效应及其机制研究

目的 观察微波辐射对海马神经元的损伤效应及其对细胞膜和[Ca^2＋]的影响，以探讨微波致海马损伤的机制。方法 采用10mW／cm^2微波辐射源辐射原代培养的海马神经元，采用MTT法测定细胞活力；流式细胞仪检测细胞凋亡和坏死率；Fluo232AM荧光探针负载、激光共聚焦显微镜扫描测定神经元胞内游离钙离子浓度；原子力显微镜观察细胞膜的改变。结果 辐射后6h，海马神经元生长活力下降（P〈0．01）；辐射后1d，细胞凋亡和坏死率增加（P〈0．01）；辐射后即刻，神经元内[Ca^2＋]荧光强度增加（P〈0．01），细胞膜穿孔。结论 微波辐射后海马神经元生长活力下降，凋亡和坏死率增加；神经元膜穿孔及胞内[Ca^2＋]增加是其损伤重要机制。     

电磁脉冲对海马神经元的损伤及其对[Ca2+]i的影响

背景:电磁脉冲照射可影响实验大鼠的学习记忆功能,并造成大鼠海马组织损伤和超微结构改变。目的:观察电磁脉冲对离体培养的海马神经元的损伤效应及其对[Ca2 ]i的影响,以深入分析电磁脉冲致脑损伤的可能机制。设计:随机对照动物实验。单位:承德医学院病理教研室。材料:Wistar乳鼠若干只,雌雄各半。电磁脉冲辐射源:高场强电磁脉冲模拟源。方法:实验于2004-03/12分别在军事医学科学院和承德医学院完成。Wistar乳鼠若干只,麻醉下断头取脑,分离海马组织,调整细胞悬液浓度至5×108L-1接种。分组:①培养细胞分为对照组和照射组,于照射后即刻(0h)收集细胞进行形态学观察和胞内游离钙离子浓度测定;②另培养细胞分为对照组和照射后0h组和12h组,进行细胞凋亡和坏死率的测定。(培养细胞用量:每项检查每组1个培养瓶,重复3次。)电磁脉冲辐射条件为6×104V/m,脉冲上升时间为20ns,脉宽为30μs,频率为2.5脉冲/min,作用2min。原代培养的海马神经元经电磁脉冲辐射后,倒置相差显微镜下观察照射前后神经元形态学变化;FACS法检测细胞凋亡和坏死;Fluo-3-AM荧光探针负载、激光共聚焦显微镜扫描测定神经元胞内游离钙离子浓度[Ca2 ]i。主要观察指标:神经元形态学变化;细胞凋亡率和坏死率;胞内游离钙离子浓度[Ca2 ]i。结果:①电磁脉冲辐射后即刻,神经细胞逐渐发生液化,神经元突起回缩、变性。②电磁脉冲辐射后12h凋亡率较辐射后即刻有所恢复,但与对照组相比均显著增加[(59.27±1.27)%,(72.17±6.21)%,(17.45±5.63)%,P<0.05]。③在辐射后即刻和12h坏死率比对照组升高,但差异无统计学意义[(13.71±2.31)%,(11.96±1.04)%,(8.45±0.67)%,P>0.05]。④电磁脉冲辐射后即刻[Ca2 ]i荧光强度显著高于对照组(107.34±26.14,54.93±16.08,P<0.05)。结论:电磁脉冲致海马神经元形态学损伤、坏死与凋亡率增加,神经元内的Ca2 荧光强度明显增加。     

电磁脉冲对大鼠海马N-甲基-D-天门冬氨酸受体活性的影响

目的　观察电磁脉冲 (EMP)辐射对大鼠海马组织中N 甲基 D 天门冬氨酸 (NMDA)受体的影响 ,以深入探讨EMP致学习记忆障碍的机制。方法　EMP辐射条件为 6× 10 4V/m ,脉冲上升时间 2 0ns ,脉宽 3 0 μs ,频率 2 .5脉冲 /min ,作用 2min。二级雄性Wistar大鼠 3 2只 ,随机分为EMP组 (n =2 6)和对照组(n =6)。EMP组大鼠分别于辐射后即刻 ,3h ,6h ,2 4h和 48h断头取脑 ,剥离海马 ,制备膜受体蛋白 ,以3 H Glu为配基进行放射性配基 受体结合实验。结果　EMP辐射后即刻大鼠海马中NMDA受体的Kd值开始下降 ,辐射后 3h下降最显著 (与对照组相比 ,P <0 .0 5 ) ,6h渐有恢复 ,48h恢复至正常水平 ;受辐射的大鼠海马中NMDA受体的Bmax值于辐射后 3h和 6h显著下降 (与对照组相比 ,均P <0 .0 5 ) ,2 4h渐有恢复 ,辐射后 48hBmax值明显升高 ,超过对照组水平 (P <0 .0 5 )。结论　EMP辐射可引起大鼠海马组织中NMDA受体亲和力升高及受体密度下降。提示NMDA受体密度、亲和力的改变以及NMDA Ca2 NO路径的兴奋毒性作用可能参与了EMP致实验动物认知障碍的分子机制。     

电磁脉冲对猴、犬及兔眼组织的辐射损伤

目的　采用高场强电磁脉冲 (electromagneticpulse ,EMP)辐射实验动物猴、犬、兔 ,并对比观察各种动物角膜、晶状体及视网膜的病理改变 ,从而研究EMP辐射对上述 3种动物视觉系统的影响。方法　采用场强为 6× 10 4V /m的EMP重复辐射猴、犬、兔各 10次 ,并于辐射后不同时间点对比观察其角膜、晶状体及视网膜的病理改变。结果　根据光镜观察结果 ,发现上述各组动物经EMP辐射后的损伤程度为 :猴 >犬 >兔 ,提示EMP的辐射损伤效应具有种属差异。实验动物视觉系统各部分对EMP辐射的损伤敏感程度依次为 :晶状体 >角膜 >视网膜。经EMP辐射后 ,猴、兔晶状体易发生后囊混浊 ,而犬晶状体易发生前囊混浊 ,主要的病理改变包括晶状体水肿、空泡形成及白内障发生等。上述 3种实验动物角膜及视网膜的病理损伤程度基本一致。结论　高场强EMP辐射可引起猴、犬、兔等实验动物的视觉系统损伤 ,其中以晶状体对EMP辐射最为敏感 ,可诱发白内障形成。     

低强度超声增加前列腺癌细胞膜通透性的体外实验研究

目的探讨低强度超声照射下前列腺癌细胞的细胞膜通透性变化。方法频率为1MHz低强度超声以连续模式照射6孔板中的单层贴壁LNCaP前列腺癌细胞,以正常细胞膜非通透性荧光染料-钙黄绿素(Calcein)标记细胞膜通透性增加的细胞,以核酸荧光染料-碘化丙啶(PI)标记死亡细胞。在声强为160mW/cm2超声下照射5s,荧光显微镜观察细胞膜通透性改变,扫描电镜观察细胞膜的形态变化;分别在不同低声强(80mW/cm2、120mW/cm2和160mW/cm2)超声下照射5s,另外在声强为120mW/cm2超声下分别照射5s、10s和15s,流式细胞仪分析细胞膜通透性增加的细胞比例与声强及照射时间的对应关系。结果低强度超声作用后,荧光显微镜显示部分单层贴壁LNCaP前列腺癌细胞摄取Calcein而呈现绿色荧光,而对照组无细胞摄取Calcein;扫描电镜显示正常LNCaP前列腺癌细胞表面有密集微绒毛,而超声作用后细胞膜表面绒毛稀少、变平,少数细胞表面出现裂孔;流式细胞仪显示细胞膜通透性增加的细胞比例分别随声强和照射时间的增加而增加。结论低强度超声可以增加前列腺癌细胞膜通透性,细胞膜通透性增加的细胞表面变平,少数出现裂孔;细胞膜通透性增加的细胞比例与声强和照射时间均呈正相关。     

电磁辐射诱导乳鼠大脑皮层神经元凋亡的研究

目的　以体外原代培养的皮层神经元为对象 ,研究电磁脉冲 (场强为 6× 10 4 V m)辐射后早期神经细胞死亡和凋亡的变化情况 ,并探讨电磁脉冲的可能致伤机制。方法　于照射后 1h、6h、12h、2 4h和 48h分别采用MTT比色法和流式细胞术测定细胞活力和凋亡细胞的比例 ,用HE染色及TUNEL检测细胞凋亡并分别用普通光学显微镜和萤光显微镜进行凋亡观察。结果　电磁脉冲辐射后 ,神经细胞不仅发生快速的坏死 ,而且还发生细胞凋亡 ,于辐射作用后 12h达到高峰。结论　电磁脉冲辐射后早期可导致神经细胞凋亡和坏死 ,此改变可能与电磁脉冲致细胞DNA损伤有关。     

电磁脉冲对海马神经元的损伤及其对[Ca^2＋]i的影响

背景：电磁脉冲照射可影响实验大鼠的学习记忆功能，并造成大鼠海马组织损伤和超微结构改变。 目的：观察电磁脉冲对离体培养的海马神经元的损伤效应及其对[Ca^2＋]i的影响，以深入分析电磁脉冲致脑损伤的可能机制。 设计：随机对照动物实验。 单位：承德医学院病理教研室。 材料：Wistar乳鼠若干只，雌雄各半。电磁脉冲辐射源：高场强电磁脉冲模拟源。 方法：实验于2004—03／12分别在军事医学科学院和承德医学院完成。Wistar乳鼠若干只，麻醉下断头取脑，分离海马组织，调整细胞悬液浓度至5&;#215;10^8L^-1接种。分组：①培养细胞分为对照组和照射组，于照射后即刻（0h）收集细胞进行形态学观察和胞内游离钙离子浓度测定；②另培养细胞分为对照组和照射后0h组和12h组，进行细胞凋亡和坏死率的测定。（培养细胞用量：每项检查每组1个培养瓶，重复3次。）电磁脉冲辐射条件为6&;#215;10^4V／m，脉冲上升时间为20ns，脉宽为30μs，频率为2．5脉冲／min，作用2min。原代培养的海马神经元经电磁脉冲辐射后，倒置相差显微镜下观察照射前后神经元形态学变化；FACS法检测细胞凋亡和坏死；Fluo-3-AM荧光探针负载、激光共聚焦显微镜扫描测定神经元胞内游离钙离子浓度[Ca^2＋]i。 主要观察指标：神经元形态学变化；细胞凋亡率和坏死率；胞内游离钙离子浓度[Ca^2＋]。 结果：①电磁脉冲辐射后即刻，神经细胞逐渐发生液化，神经元突起回缩、变性。②电磁脉冲辐射后12h凋亡率较辐射后即刻有所恢复，但与对照组相比均显著增加[（59．27&;#177;1．27）％，（72．17&;#177;6．21）％，（17．45&;#177;5．63）％，P〈0．051。③在辐射后即刻和12h坏死率比对照组升高，但差异无统计学意义[（13．71&;#177;2．31）％，（11．96&;#177;1．04）％，（8．45&;#177;0．67）％，P〉0．05]。④电磁脉冲辐射后即刻[Ca^2＋]i荧光强度显著高于对照组（107．34&;#177;26．14，54．93&;#177;16．08，P〈0．05）。 结论：电磁脉冲致海马神经元形态学损伤、坏死与凋亡率增加，神经元内的Ca^2＋荧光强度明显增加。     

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.