血小板活化因子参与血小板-中性粒细胞活化的研究

本研究的目的是探讨全血中血小板活化因子(platellet-activating factor，PAF)参与血小板-中性粒细胞相互作用的病理-生理机制，为PAF受体拮抗剂的临床应用提供理论依据。将PAF受体拮抗剂银杏内酯B(ginkgolides B，GB BN52021)加入全血中，以阻断PAF对血小板．中性粒细胞的活化作用；将已知的PAF及二磷酸腺苷(ADP)分剐加入全血中，用流式细胞术(FCM)检测血小板cD62P的表达；将已知的PAF及ADP分剐加入全血中，用FCM检测中性粒细胞细胞CD11b的表达；将PAF及ADP分别加入全血中，用FCM检测血小板-白细胞聚集物(PLA)，即PLA/L包括百分率及CD42b中位荧光浓度(MFI)。结果表明：PAF及ADP均增加CD62P、CD11b、PLA的表达：PAF受体拮抗剂(银杏内酯B)明显抑制PAF诱导的CD62P、CD11b的表达及PLA的形成，但不能完全抑制血小板、中性粒细胞的活化及血小板-白细胞之间的相互作用；银杏内酯B也抑制ADP诱导的CD62P、CD11b的表达，但不能完全抑制血小板、中性粒细胞活化；银杏内酯B对ADP诱导的血小板-白细胞的聚集无明显抑制作用。结论：血小板-中性粒细胞的相互作用机制复杂，有多种细胞因子、化学介质参与其中，有多种配基-受体介导血小板-中性粒细胞的交互作用。PAF受体拮抗剂-银杏内酯B有明显拮抗PAF的作用，在防治血栓形成与炎症过程中可能具有广泛的应用前景。     

蛋白激酶C与钙离子在凝血酶受体活化过程中的作用

目的 比较两类凝血酶受体活化过程中蛋白激酶C(PKC)与钙离子(Ca2+)对血小板聚集率以及血小板膜表面活化标志物糖蛋白(GP)Ⅰ b表达的影响,探讨G蛋白q(Gq)信号途径在凝血酶受体活化过程中的作用.方法 分别以凝血酶受体活化肽PAR1-AP(SFLLRN)与PAR4-AP(AYPGKF)模拟各自的固定配基活化血小板.观测PKC选择性抑制剂Ro-31-2220与胞内Ca2+螯合剂(BAPTA/AM)作用过程中血小板聚集与血小板膜表面GP Ⅰ b的改变.结果 两类凝血酶受体活化肽均能诱导血小板活化,产生完全的聚集波,血小板膜GP Ⅰ b则呈现进行性减少后逐渐回升的可逆性变化.BAPTA与Ro-31-2220预处理后蛋白激酶活化受体(PAR)肽诱导的血小板聚集被抑制,但形态变化依然存在.Ro-31-2220明显抑制PAR1-AP引起的GP Ⅰ bα内陷[1 min时为(87.0±0.04)%,2 min时为(73.00±0.08)%,P《0.05];PAR4-AP可以延长GP Ⅰ bα在胞内的逗留,减缓其返回血小板表面的进程[10 min时为(44.00±0.01)%,30 min时为(46.00±0.05)%,P《O.05].BAPTA则能明显抑制两类PAR肽引起的GP Ⅰ bα内陷[1 min时分别为(94.00±0.08)%和(95.00±0)%,2 min时分别为(92.00±0.02)%和(94.00±0.01)%,5 min时分别为(91.00±0.02)%和(91.00±0.02)%,10 min时分别为(90.00±0.04)%和(87.00±0.03)%,各时间点之间比较P值均《0.05].结论 PKC与Ca2+在凝血酶受体活化中发挥重要作用.Ca2+与凝血酶受体活化过程密切相关,对两类受体作用相似.PKc在PAR1途径促使GP Ⅰ b内陷,在PAR4途径则加速GP Ⅰ b重返膜表面.     

西红柿汁体外抑制血小板聚集功能及其机制探讨

目的:观察西红柿汁在体外对血小板聚集、血小板活化标志物的表达及对血小板纤维蛋白原结合量的影响,初步探讨西红柿汁对血小板聚集功能的影响机制。方法:将不同浓度的西红柿汁与正常人富血小板血浆(PRP)孵育,加入5-腺苷二磷酸二钠盐(ADP)和胶原,观察西红柿汁对血小板聚集的影响。用ADP及胶原激活血小板,流式细胞仪(FCM)分析西红柿汁对活化血小板纤维蛋白原受体(Fib-R)和P-选择素(CD62P)的表达水平及血小板纤维蛋白原结合量的影响。结果:西红柿汁能够明显抑制由ADP、胶原诱导的血小板聚集,且随着西红柿汁浓度的增加,对血小板聚集的抑制率增高。西红柿汁不能抑制ADP、胶原诱导的血小板Fib-R、CD62P表达,但能显著抑制由ADP、胶原诱导的血小板与纤维蛋白原结合量。结论:西红柿汁在体外能够显著抑制血小板聚集,其抗血小板聚集的作用机制与阻碍纤维蛋白原与血小板Fib-R结合有关。西红柿汁具有潜在的抗血小板治疗前景。     

抗幽门螺杆菌尿素酶B单抗对人血小板聚集与活化的影响及其机制研究

目的研究抗幽门螺杆菌尿素酶B（Hp ureB）单克隆抗体（1F11）对二磷酸腺苷（ADP）诱导的人血小板聚集与活化的影响及其机制。方法采用Western blot分析血小板膜糖蛋白（GP）成分与1Fll的相关性，采用比浊法检测血小板聚集情况，分别用双抗夹心、抗原竞争的酶联免疫测定法检测各组血浆中的P-选择素、血栓烷B2。通过流式细胞术（FCM）分析单抗1F11与SZ21单抗对血小板GPⅢa的竞争性。结果1F11与血小板成分GPⅢa有一定程度结合，1F11单抗可明显抑制ADP诱导的人血小板的聚集，随着1F11浓度的增加，血小板聚集抑制率呈剂量依赖性增高，但1F11并不抑制血浆中P-选择素、血栓烷B2的水平。FCM结果显示：加单抗1F11后可使FITC—SZ21单抗与血小板结合的阳性细胞率从99．5％降至77．4％。，结论1F11可与人血小板GPⅢa结合并抑制血小板聚集，但不能阻止血小板的活化过程。HpureB与人血小板GPma具有交叉识别的抗原表位。提示幽门螺杆菌可能与ITP发病有关。     

人工合成长链多聚磷酸盐对凝血和血小板聚集的影响

目的:探讨人工合成长链多聚磷酸盐对凝血和血小板聚集的影响。方法:通过凝血常规检测、凝血因子活力检测和血小板聚集实验,检测人工合成长链多聚磷酸盐对凝血和血小板聚集的影响,采用ELISA、流式细胞术、高内涵成像技术探讨长链多聚磷酸钠盐的作用机制。结果:长链多聚磷酸盐可延长活化部分凝血活酶时间,降低凝血因子FⅧ、FⅨ、FⅪ、FⅫ活力,阻滞ADP诱导的血小板聚集,降低血小板内钙离子及TXA2浓度。结论:人工合成长链多聚磷酸盐可抑制内源性凝血并抑制血小板聚集,其机制可能与抑制血小板内钙离子及TXA2有关。     

血小板聚集功能检测方法及参数的探索与研究

目的采用5种血小板聚集功能分析仪探讨研究血小板聚集功能检测的可靠方法与准确参数。方法利用二磷酸腺苷(ADP)诱导光比浊血小板聚集仪(LTA)实验,流式细胞仪(FC)血小板膜糖蛋白分子PAC-1(Fg、Ca~(2+)、GPⅡb/Ⅲa形成复合物的受体)、CD62p(P选择素)活化百分率检测实验,英诺华PL-11血小板分析仪实验,VerifyNow抗血小板治疗监测系统实验(VerifyNow)与血栓弹力图实验(TEG)同时检测对照组与单服用氯吡格雷组的血小板聚集功能。结果(1)对照组与患者组ADP%,ADP激活的PAC-1、CD62p受体活化百分率,MAR%,INHI%,TEG测得ADP诱导的MA(mm)值6个参数差异有统计学意义(P0.05);BASE、P2Y12受体的PRU,凝血酶诱导的MA(mm)值3个参数差异无统计学意义(P0.05)。(2)ADP%与(100-INHI)%,MAR%,ADP激活的CD62p、PAC-1受体活化百分率呈正相关(r分别是0.565、0.939、0.769和0.583,P0.05);与TEG测得ADP诱导的血小板聚集率值(%Agg)无相关性(r=0.127,P0.05)。结论 (1)氯吡格雷有抗血小板聚集的效果。(2)LTA操作便捷、廉价、结果稳定,在医院普及率高,是临床监测血小板聚集功能的首选方法。     

三七皂甙单体2A-1-1对人血小板聚集和钙内流的作用

目的观察三七皂甙单体2A-1-1对人血小板聚集和钙内流的影响,并探讨其对受体操纵性钙通道的作用.方法比浊法测定血小板聚集;Fura-2/Am荧光探针双波长测定细胞胞浆游离钙浓度,观察2A-1-1、硝苯地平、SK＆F96365对二磷酸腺苷(ADP)、环匹阿尼酸(CPA)介导的人血小板钙内流的变化.结果硝苯地平(20μmol/L)不能抑制ADP诱导的血小板聚集,不能抑制ADP或CPA介导的血小板钙内流;SK＆F96365(20μmol/L)可以抑制ADP诱导的血小板聚集,抑制率为59.83%;SK＆F96365(15μmol/L)可以抑制CPA和ADP介导的钙内流;2A-1-1(5,10,20,μmol/L)可抑制ADP诱导的血小板聚集,抑制率分别为47.06%,53.47%,71.52%;2A-1-1(10,20 μmol/L)可抑制CPA和ADP介导的钙内流.结论三七皂甙单体2A-1-1能抑制人血小板聚集,抑制血小板受体操纵性钙通道,从而抑制钙内流,有抗血小板作用.     

莫诺苷对二磷酸腺苷诱导兔血小板聚集钙离子的影响

目的观察莫诺苷对二磷酸腺苷(ADP)诱导兔血小板聚集后Ca²⁺+浓度的影响。方法利用钙离子荧光探针(Fura-2 AM)法,通过记录5 min 之内Fura-2 在激发波长340 nm和380 nm处的荧光强度比值,检测不同条件下ADP 诱导血小板聚集后Ca²⁺+的变化。结果与空白对照组相比,莫诺苷能显著抑制由ADP 诱导兔血小板聚集后Ca²⁺+的升高(P<0.001)。结论莫诺苷可能通过降低Ca²⁺+的上升达到抗ADP 诱导的兔血小板的聚集,从而改善体外血液流变学。     

活化血小板表面膜糖蛋白的异位分布

目的观察血小板活化后表面一些抗原决定簇的动态改变,探讨其在血栓性疾病研究中的意义。方法以凝血酶与腺苷二磷酸(ADP)分别在不同时间段(0~30min)诱导正常人血小板活化,应用流式细胞仪检测其血小板膜糖蛋白(GP)Ⅰb,GPⅢa及P-选择素的表达;同时用全血法测定脑梗死患者相应抗原的改变。结果凝血酶及ADP活化血小板后均可导致GPⅠb表达呈现先下降又逐渐回升的可逆性分布趋势,各时间段引起的GPⅠb改变在两者之间都具有显著差异;GPⅢa表达在活化后初期变化不明显,10min后呈现递增趋势;两种活化剂均可促使P-选择素显著升高,并维持于高水平。脑梗死患者GPⅠb表达减少,P-选择素的表达远高于对照组,GPⅢa无变化。结论凝血酶与ADP均能介导血小板活化,以时间依赖的方式促使GPⅠb与GPⅢa逆转,同时P-选择素向外释放,而血小板表面活化相关性抗原的改变是反映体内血小板活化的重要指标。     

血管性血友病的实验诊断

血管性血友病因子(von Willebrand factor,vWF)是血管内皮细胞和骨髓巨核细胞合成的一种糖蛋白,正常情况下存在于血浆和血小板(占全血15%)中。vWF 可与血小板膜糖蛋白 GP Ⅰb/Ⅸ/Ⅴ结合,激活 GPⅡb/Ⅲa 并桥接血小板与vWF,从而促使血小板聚集;vWF 还可介导血小板黏附到内皮细胞损伤后暴露出的胶原表面,使血小板聚集,形成血小板血栓,在一期止血中起重要作用。此外,血浆中的 vWF 还与 FⅧ形成复合物以稳定 FⅧ,在二期止血中发挥重要作用。vWF 缺乏将导致患者出现血管性血友病(von Willebrand     

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.     

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.     

Systematic Reviews Published in the January 2011 Issue of The Cochrane Library

ABSTRACT

The Cochrane Library of Systematic Reviews is published quarterly as a DVD and monthly online. The January 2011 issue (first quarterly DVD for 2011) contains 4515 complete reviews, 1985 protocols for reviews in production, and 13,521 one-page summaries of systematic reviews published in the general medical literature. In addition, there are citations of 641,000 randomized controlled trials, and 14,018 cited papers in the Cochrane methodology register. The health technology assessment database contains over 9300 citations. One hundred and seven new reviews have been published in the last 3 months, of which five have potential relevance for practitioners in pain and palliative medicine.     

Interprofessional approaches to creating safe,high quality health care

Three supplementary perspectives are presented arguing that interprofessional collaboration is both necessary and desirable. Nonetheless, there are often too many serious intra-professional barriers and obstacles to interprofessional collaboration to make it successful. Some of these barriers, it is argued and illustrated, are found in the multiple ways in which professional identity is tacitly acquired and embodied in the practitioners' habitual, everyday practice. The paper then explores ways in which reflection, especially Second order reflection, can help to elucidate and overcome these obstacles, as well as increasing professional adaptability and competence.     

Modified micro-superior percutaneously-assisted total hip: early experiences & case reports

Because of the extensile nature and familiarity of the standard posterior-lateral approach to the hip, a family of "micro-posterior" approaches has been developed. This family includes the Percutaneously-Assisted Total Hip (PATH) approach, the Supercapsular (SuperCap) approach and a newer hybrid approach, the Supercapsular Percutaneously-Assisted Total Hip (SuperPATH) approach. Such approaches should ideally provide a continuum for the surgeon: from a "micro" (external rotator sparing) posterior approach, to a "mini" (external rotator sacrificing) posterior approach, to a standard posterior approach. This could keep a surgeon within his comfort zone during the learning curve of the procedure, while leaving options for complicated reconstructions for the more practiced micro-posterior surgeons. This paper details one author's experiences utilizing this combined approach, as well as permutations of this entire micro-posterior family of approaches as applied to more complex hip reconstructions.     

Prise en charge des entorses externes de cheville : étude clinique préliminaire sur l’efficacité du dispositif Myolux™

Ankle sprains are the most common injury of the musculoskeletal system and are associated with significant societal and economic impacts. It has been proven that classical therapeutic strategies may not be effective in preventing recurrent injuries: the recurrence rates reported in the literature can reach 73%. In order to provide an effective rehabilitation solution, a destabilizing orthosis was developed. This device is equipped with a mechanical articulator reproducing the subtalar mechanics and placed under the heel. In this paper, we present the main results of a preliminary clinical study conducted between 2004 and 2007. All subjects included in this study were treated with the abovementioned orthosis during 10 rehabilitation sessions of 30 minutes each. Data show a relatively low recurrence rate of 12% for the overall population. Moreover, it's of primary importance to note that this satisfactory ratio is largely reduced (3% of recurrence rate) for the 29 patients who performed one training session per month after the 10th initial rehabilitation sessions. Hence, the destabilizing orthosis appears to be an effective solution to prevent recurrent ankle sprains. However, joint protection requires long-term and regular training sessions. This result has motivated the development of a similar device allowing patients to perform training sessions at home. Finally, data obtained in this study are promising awaiting the final results of the comparative, multicentric and independent clinical trials currently managed by the Hospices Civils de Lyon.     

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.