人参皂甙Rg1对大鼠海马神经元缺糖氧/复糖氧后氧化损伤的保护作用

目的观察人参皂甙Rg1 对大鼠海马神经元缺糖氧/复糖氧后谷胱甘肽(GSH)和谷胱甘肽过氧化物酶(GPx)的影响。方法海马神经元培养8~10 d,随机分为正常对照组、模型组、人参皂甙Rg1 低、中、高剂量组(5 μmol/L, 20 μmol/L, 60 μmol/L)。建立大鼠海马神经元缺糖氧/复糖氧模型,复糖氧后6 h 以生物化学法观察各组海马神经元GSH含量和GPx活性的变化;复糖氧后24 h 以Hochest 染色法检测细胞凋亡,并检测各组海马神经元四甲基偶氮唑盐(MTT)代谢率。结果与模型组相比,人参皂甙Rg1中、高剂量组海马神经元GSH含量、GPx活性显著升高,凋亡显著减少,MTT代谢率显著提高(P<0.001),人参皂甙Rg1 低剂量组变化不明显(P>0.05)。结论人参皂甙Rg1 可通过提高缺糖氧神经元GSH含量和GPx活性,发挥脑保护作用。     

大鼠海马神经元体外氧糖剥夺/复氧模型的构建

目的 建市体外培养的大鼠海马神经元氧糖剥夺(OGD)/复氧实验模型,并尝试确定该模型最合适的缺氧缺糖时间点.方法 新生SD乳鼠海马神经元原代培养7 d后,随机(随机数字法)分为OGD组和对照组.OCD组根据氧糖剥夺时间的不同又分为1 h,2 h,4 h,6 h,8 h,10 h亚组.OGD组细胞置于含0.5%氧气的三气培养箱,同时将培养液换成无糖Earle氏液,模拟体内脑缺血损伤.复氧复糖24 h后观察对照组和OCD各组的神经元形态,测定MTT细胞光密度值(OD)和培养液LDH含量,流式细胞仪检测细胞凋亡率.所得数据采用SPSS 16.0统计软件行单因素方差分析(Dunnett-t检验)和Spearman等级相关分析.结果 随着缺氧缺糖时间的延长,OGD各组神经元形态学损伤逐步加重,细胞OD值和存活率逐渐下降(rs=-0.961和rs=-0.966,P<0.01),LDH值逐渐升高(rs=0.990,P<0.01),细胞凋亡率明显增加,与对照组比较差异均有统计学意义(P<0.05).OGD6 h时,细胞的凋亡率接近50%.结论 成功建立了大鼠海马神经元体外氧糖剥夺/复氧模型,结合形态学改变和细胞凋亡率,建议将6 h作为该模型合适的缺氧缺糖损伤时间.     

人参皂苷Rg1对大鼠海马神经元缺糖氧／复糖氧后钙内流的影响北大核心CSCD

目的观察人参皂苷Rg1对大鼠海马神经元缺糖氧／复糖氧后钙内流的影响,并探讨其可能的脑保护机制。方法建立大鼠海马神经元缺糖影复糖氧模型,随机分为正常对照组、模型组和人参皂苷Rg1干预组（5、20、60μmol／L）。复糖氧后24h以Fluo-3 AM荧光染色法观察各组海马神经元细胞内钙离子浓度变化,以Hoechst染色法检测细胞凋亡,并检测细胞四甲基偶氮唑盐（MTT）代谢率。结果与模型组比较,人参皂苷Rg1中、高剂量组海马神经元细胞内钙离子浓度降低,凋亡细胞减少,MTT代谢率升高,人参皂苷Rg1低剂量组变化不明显。结论脑缺血后神经元细胞内钙超载与脑损伤关系密切,人参皂苷Rg1可通过减少缺糖氧神经元细胞内钙内流,发挥脑保护作用。     

脑缺血—再灌注后BDNF和bFGF表达与神经元凋亡的关系及脑脉康的干预作用

目的:观察脑缺血-再灌注损伤后脑源性神经营养因子(BDNF)、碱性成纤维细胞生长因子(bFGF)蛋白表达与神经元凋亡的关系,探讨脑脉康的干预作用及机制.方法:建立大鼠脑缺血-再灌注损伤模型,应用脑脉康进行干预.采用免疫组化方法和凋亡原位末端标记技术(TUNEL),观察脑缺血3 h及再灌注7、24、96和168 h的BDNF、bFGF蛋白分布、表达的动态变化与凋亡细胞分布与时相关系以及脑脉康的干预作用.结果:模型组大鼠缺血3 h、再灌注7 h半暗区皮质及新纹状体区BDNF、bFGF表达即明显升高,再灌注24 h达到高峰;缺血侧海马CA1～CA3区及丘脑则于再灌注96 h达到高峰.缺血侧半暗区神经元凋亡于24～96 h达到高峰;海马CA1～CA3区及丘脑、纹状体区于再灌注168 h仍有相当数量的凋亡细胞.与对照组比较,中药组于再灌注24～168 h BDNF、bFGF表达显著升高(P<0.05或P<0.01),凋亡细胞数则明显减少(P<0.05或P<0.01).结论:脑缺血-再灌注损伤后BDNF、bFGF的表达升高,在一定程度上可抑制神经元凋亡,促进神经功能状态的恢复,对脑缺血损伤有重要的保护作用.脑脉康可能通过促进脑缺血-再灌注损伤后BDNF、bFGF表达,激活内源性神经保护机制,发挥其抗凋亡作用.     

三七总皂甙对大鼠海马神经细胞凋亡的影响

目的:以原代培养的大鼠海马神经细胞缺氧/缺糖再给氧为模型,观察三七总皂甙对神经细胞凋亡的抑制作用。方法:流式细胞术检测凋亡细胞百分率,激光共聚焦扫描显微镜检测细胞内Ca2 浓度,荧光显微镜观察细胞形态学变化和坏死细胞百分率,同时,测定细胞LDH的释放。结果:神经细胞缺氧/缺糖5h后再给氧3h时,细胞凋亡百分率明显增高,为19.06%(P<0.01),细胞坏死百分率为6.83%(P<0.01),细胞内Ca2 浓度为169.32nmol/LCa2 浓度(P<0.01),LDH的释放率为27.63%(P<0.01);神经细胞缺氧/缺糖5h后再给氧24h时,细胞凋亡百分率为49.85%(P<0.01),细胞坏死百分率为11.49%(P<0.01),细胞内Ca2 浓度为298.11nmol/L(P<0.01),LDH的释放率为60.35%(P<0.01)。三七总皂甙(25,50mg/L)能降低神经细胞凋亡及坏死的百分率,降低细胞内Ca2 浓度,减少LDH的释放,三七总皂甙的作用随剂量增加而作用增加。结论:三七总皂甙对缺血再灌注损伤后海马神经元的凋亡过程具有抑制作用,这种作用可能与其能降低细胞内Ca2 浓度有关。     

银杏叶提取物对神经元缺糖缺氧/复糖复氧性损伤的作用

目的研究银杏叶提取物(EGB761)对体外培养神经元缺糖缺氧/复糖复氧性损伤的作用,并探讨其作用机制。方法利用体外培养的皮层神经元,通过去除培养液中的葡萄糖和氧气(oxygen andglucose deprivation,OGD)模拟缺血缺氧,恢复糖氧供给模拟再灌流。再灌流时分三组加入不同浓度的EGB761观察其作用。噻唑盐比色法(MTT)测定细胞活性,碘化丙锭(PI)与Hoechst33258双染色观察神经元凋亡,免疫蛋白印迹法测定Bcl-2、Bax蛋白的表达。结果EGB761可减少缺糖缺氧/复糖复氧导致的神经元凋亡,提高因该损伤而下降的MTT值以及Bcl-2蛋白的表达。Bax蛋白在EGB761处理前后均无明显变化。结论EGB761可拮抗缺糖缺氧/复糖复氧导致的神经元凋亡,并且该作用可能与诱导Bcl-2蛋白表达有关。     

垂体腺苷环化酶激活肽对缺血再灌注脑神经元凋亡的作用

目的：观察垂体腺苷环化酶激活肽（pituitary adenylate cyclase-activating polypeptide,PACAP)对缺血再灌注脑神经元凋亡的防治作用。方法：利用四血管结扎法，建立老龄大鼠脑缺血再灌注模型，侧脑室注射PACAP，观察脑组织丙二醛（MDA）含量和超氧化物歧物酶（SOD）、谷胱甘肽过氧化物酶（GSH－Px)活性，计数海马CA1区存活和凋亡神经元数目，电镜观察神经元的超微结构变化。结果：PACAP治疗后脑组织MDA含量为（1．35&;#177;0．39）nmol/mg,SOD和GSH－Px活性分别为（115&;#177;20）NU／mg、（10．3&;#177;2．0）U／mg，与缺血再灌注组有明显差异（P＜0．05），海马CA1区存活和凋亡神经元数目为48．8&;#177;4．3，14．3&;#177;2．9，能促进神经元存活和减轻凋亡损伤（P＜0．01），保护超微结构。结论：PACAP的保护作用可能与其降低脑组织氧自由基水平，提高抗氧化酶活性，防止神经元凋亡有关。     

人参皂甙Rgl对脑缺血后神经元型一氧化氮合酶的影响

目的：观察人参皂甙Rgl对大鼠海马神经元缺糖氧／复糖氧后钙内流和神经元型一氧化氮合酶（nNOS）的影响,并探讨其可能的脑保护机制。方法：建立大鼠海马神经元缺糖氧／复糖氧模型,随机分为正常对照组、模型组和人参皂甙Rgl干预组（5、20、60μmol／L）。复糖氧后24h以Fluo-3AM荧光染色法观察各组海马神经元细胞内钙离子浓度变化,以生物化学法观察nNOS活性的变化,并以Hochest染色法检测细胞凋亡。结果：与模型组相比,人参皂甙Rgl中、高剂量组海马神经元细胞内钙离子浓度和nNOS活性均降低,凋亡细胞减少,人参皂甙Rgl低剂量组变化不明显。结论：人参皂甙Rgl可通过减少缺糖氧神经元细胞内钙内流,进而抑制nNOS活性,发挥脑保护作用。     

垂体腺苷环化酶激活肽对缺血再灌注脑神经元凋亡的作用

目的:观察垂体腺苷环化酶激活肽(pituitaryadenylatecyclase-activatingpolypeptide,PACAP)对缺血再灌注脑神经元凋亡的防治作用。方法:利用四血管结扎法,建立老龄大鼠脑缺血再灌注模型,侧脑室注射PACAP,观察脑组织丙二醛(MDA)含量和超氧化物歧物酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性,计数海马CA1区存活和凋亡神经元数目,电镜观察神经元的超微结构变化。结果:PACAP治疗后脑组织MDA含量为(1.35±0.39)nmol/mg,SOD和GSH-Px活性分别为(115±20)NU/mg、(10.3±2.0)U/mg,与缺血再灌注组有明显差异(P<0.05),海马CA1区存活和凋亡神经元数目为48.8±4.3,14.3±2.9,能促进神经元存活和减轻凋亡损伤(P<0.01),保护超微结构。结论:PACAP的保护作用可能与其降低脑组织氧自由基水平,提高抗氧化酶活性,防止神经元凋亡有关。     

LPA2在PC12细胞缺血再灌注损伤致细胞凋亡中的作用

目的探讨溶血磷脂酸(LPA)2受体在PC12细胞缺血再灌注损伤致细胞凋亡中的作用。方法以实验方法完成研究,通过建立PC12细胞缺血再灌注受损细胞模型,分别于缺氧环境中培养0、3、6、9、12、15h以进行糖氧剥夺,之后再将其放入高糖培养基中再次复氧培养24h,然后利用MTT来检测细胞存活率,并对其进行分组,分为正常组、缺血再灌注组(A组)、缺血再灌注+溶剂对照组(B组)、缺血再灌注+LPA2激动剂组(C组)、缺血再灌注+LPA2抑制剂组(D组)。先进行缺氧培养一定时间后再复氧培养24h,并采用MTT检测细胞存活率,同时,检测LPA2受体与P-akt蛋白的表达情况。结果经糖氧剥夺培养6h后,缺血再灌注的细胞存活率较正常组明显下降,差异有统计学意义(P0.05),且缺血再灌注损伤糖氧剥脱处理最适时间为12h。A组LPA2表达水平明显低于B组;C组与B组相比较,LPA2表达水平显著增高,且P-akt表达水平显著增高,差异有统计学意义(P0.05)。结论 LPA2受体在PC12细胞缺血再灌注损伤致细胞凋亡中起着重要的保护作用,且升高LPA2受体表达水平有助于提高细胞生存率。     

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.     

Guns and Knives in New Mexico: Patterns of Penetrating Trauma, 1978–1993

Objective: To identify patterns of nonfatal and fatal penetrating trauma among children and adults in New Mexico using ED and medical examiner data.
Methods: The authors retrospectively sampled in 5-year intervals all victims of penetrating trauma who presented to either the state Level-1 trauma center or the state medical examiner from a 16-year period (1978–1993). Rates of nonfatal and fatal firearm and stabbing injury were compared for children and adults.
Results: Rates of nonfatal injury were similar (firearm, 34.3 per 100,000 person-years; stabbing, 35.1). However, rates of fatal injury were significantly different (firearm, 21.9; stabbing, 2.7; relative risk: 8.2; 95% confidence interval: 5.4, 12.5). From 1978 to 1993, nonfatal injury rates increased for children (p = 0.0043) and adults (p < 0.0001), while fatal penetrating injury remained constant. The increase in nonfatal injury in children resulted from increased firearm injury rates. In adults, both stabbing and firearm nonfatal injury rates increased.
Conclusions: Nonfatal injury data suggest that nonfatal violence has increased; fatal injury data suggest that violent death rates have remained constant. Injury patterns vary by age, mechanism of trauma, and data source. These results suggest that ED and medical examiner data differ and that both are needed to guide injury prevention programs.