Spinal canal narrowing during simulated frontal impact

Between 23 and 70% of occupants involved in frontal impacts sustain cervical spine injuries, many with neurological involvement. It has been hypothesized that cervical spinal cord compression and injury may explain the variable neurological profile described by frontal impact victims. The goals of the present study, using a biofidelic whole cervical spine model with muscle force replication, were to quantify canal pinch diameter (CPD) narrowing during frontal impact and to evaluate the potential for cord compression. The biofidelic model and a sled apparatus were used to simulate frontal impacts at 4, 6, 8, and 10 g horizontal accelerations of the T1 vertebra. The CPD was measured in the intact specimen in the neutral posture (neutral posture CPD), under static sagittal pure moments of 1.5 Nm (pre-impact CPD), during dynamic frontal impact (dynamic impact CPD), and again under static pure moments following each impact (post-impact CPD). Frontal impact caused significant (P<0.05) dynamic CPD narrowing at C0-dens, C2-C3, and C6-C7. The narrowest dynamic CPD was observed at C0-dens during the 10 g impact and was 25.9% narrower than the corresponding neutral posture CPD. Interpretation of the present results indicate that the neurological symptomatology reported by frontal impact victims is most likely not due to cervical spinal cord compression. Cord compression due to residual spinal instability is also not likely.     

肠缺血后处理对兔缺血再灌注损伤小肠上皮细胞线粒体形态和功能的影响

目的观察缺血后处理对小肠缺血再灌注损伤的保护作用。方法30只大白兔随机分为3组，每组8只：A组，假手术组；B组，肠缺血再灌注损伤模型组；C组，肠缺血再灌注损伤模型肠缺血后处理组，实验结束后取小肠标本进行小肠上皮细胞形态和呼吸功能指标测定。结果A、C两组线粒体的数目、周长均大于B组，A、C两组问比较，A组较大（P〈0．05）。A、C两组线粒体的面积、最大直径、最小直径、等效直径均小于B组（P〈0．05），A、C两组间比较差异无统计学意义（P〉0．05）。B组线粒体的体积密度小于A组，面积密度、比表面和粒子数密度均小于其余两组（P〈0．05）。A、C两组间三维平面形态计量学各参数比较差异无统计学意义（P〉0．05）；B、C组线粒体呼吸控制比率（RCR）低于A组差异有统计学意义（P〈0．05），与C组比较，B组下降更为明显（P〈0．05）。结论小肠缺血后处理对缺血再灌注损伤肠上皮细胞线粒体形态和功能均有保护作用。     

脂肪来源间充质干细胞对大鼠肝移植的免疫调节作用

目的探讨大鼠脂肪来源间充质干细胞(MSC)对大鼠肝移植术后急性排斥反应的作用。方法分离、培养SD大鼠MSC,体外混合淋巴细胞培养(MLC)体系中,研究MSC对Wistar大鼠T细胞增殖的抑制作用。以SD与Wistar大鼠为供受体建立肝移植模型。随机分为MSC处理组与空白对照组,术后第7天检测肝功能、血清白细胞介素(IL)-2和白细胞介素(IL)-10水平、肝组织病理形态及肝细胞凋亡。结果体外MLC中,Wistar大鼠T细胞增殖明显受抑,抑制率为48.44%。实验组血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、总胆红素(TBIL)、IL-2、IL-10分别为(134.2±45.0)、(162.5±30.5)U/L、(30.6±5.4)μmol/L、(187.35±18.26)、(193.95±37.62)μg/L;对照组上述指标分别为(355.6±54.3)、(296.4±71.2)U/L、(145.7±28.6)μmoL/L、(295.73±57.15)、(75.12±11.23)μg/L,两组差异有统计学意义(P<0.05);病检提示实验组排斥反应较对照组明显减轻;脱氧脲核苷酸缺口末端标记(TUNEL)检测提示实验组肝细胞凋亡程度明显低于对照组(P<0.05)。结论供体来源MSC能明显抑制MLC体系中受体源T细胞的增殖,并能显著减轻大鼠肝移植术后急性排斥反应。     

Noninvasive Intracranial Cerebral Flow Velocity Evaluation in the Emergency Department by Emergency Physicians

Transcranial Doppler (TCD) is an accepted modality for the evaluation of cerebral blood flow velocities. OBJECTIVES: The purpose of this study was to test the feasibility of bedside TCD measurement in the emergency department (ED) with critically ill, intubated patients. METHODS: A prospective convenience sample of patients presenting to a university hospital over a two-month period underwent TCD evaluation of the middle cerebral artery. Intubated patients with head trauma and any patient requiring tracheal intubation were eligible. A 2-MHz Doppler probe was positioned over the temporal bone to acquire blood flow velocities. An emergency medicine resident and research assistant obtained measurements. Continuous TCD tracings were recorded on a video cassette recorder tape for quality assurance review and data collection. Vital signs and therapeutic interventions were also recorded. Flow velocities were measured in cm/s; the peak Resistance Index (RI) was calculated for each patient. RESULTS: A total of 30 patients were enrolled in the study. Adequate tracings were obtained in 25 patients (83%) without a disruption of resuscitation. Tracings could not be obtained in five patients; they were listed as TCD failures. However, in two of these patients, adequate flow velocity tracings were obtained after resuscitation. Four patients were evaluated during tracheal intubation. One patient was monitored successfully during cardiopulmonary resuscitation. The median time required for data acquisition was 1.9 minutes. The mean highest RI for those who expired was 0.84. For those who survived, the mean highest RI was 0.52. The difference of 0.32 was statistically significant (p = 0.04). CONCLUSIONS: Noninvasive blood flow velocity monitoring of the middle cerebral artery using TCD is feasible in the ED when performed at the bedside on intubated patients with traumatic brain injury and others during tracheal intubation and resuscitation.     

Thrombotic occlusion of the common carotid artery (CCA) in acute ischemic stroke treated with intravenous tissue plasminogen activator (TPA)

Although common carotid artery (CCA) occlusions are rare, acute clinical presentations vary from mild to devastating strokes primarily due to tandem occlusions in the intracranial arteries. Three patients with acute CCA occlusions were treated with systemic tissue plasminogen activator (TPA). Blood pressures were kept at the upper limits allowed with TPA therapy with fluid balance and the 'head-down' position. Recanalization occurred in intracranial vessels only. Marked early neurological improvement occurred in two of three patients. CCA occlusions should not be considered contra-indication to systemic thrombolysis.     

缺氧诱导因子-lα与脑缺氧缺血性损伤

缺氧诱导因子-lα（hypoxia-inducible factor-1alpha，HIF-lα）是近来发现的广泛存在于哺乳动物和人体内的一种缺氧应答调控因子，在调节缺氧诱导的基因表达中起关键性作用。它可调节表达多种靶基因如血管内皮生长因子、促红细胞生成素等，对改善脑缺氧缺血后能量代谢障碍、促进脑血流动力学恢复、抑制兴奋性氨基酸毒性、减少细胞凋亡等起重要作用。通过进一步对HIF-lα及其靶基因的研究，可能为临床治疗脑缺氧缺血性损伤提供了一种新的治疗策略。     

急性冠状动脉综合征患者介入术前后血小板活化及血管内皮功能的变化

目的观察急性冠状动脉综合征患者介入治疗后血小板活化指标CD62p、CD63及糖蛋白Ⅱb/Ⅲa受体复合物及内皮功能的改变。方法60例急性冠状动脉综合征患者在冠状动脉介入术前和术后即刻以及次日采用流式细胞仪检测血小板活化指标CD62p、CD63及糖蛋白Ⅱb/Ⅲa受体复合物;双抗体夹心固相酶联免疫吸附试验测定血浆假血友病因子的表达水平;放射免疫测定法测定血浆内皮素1表达水平;酶法测定血浆一氧化氮的含量;彩色多谱勒超声诊断仪测量内皮依赖性血管舒张功能。选择健康体检者和稳定型心绞痛患者各30例作对照,观察急性冠状动脉综合征患者冠状动脉介入前后指标的变化并与对照组比较。结果与健康对照组和稳定型心绞痛组比,急性冠状动脉综合征组CD62p、CD63及糖蛋白Ⅱb/Ⅲa受体复合物明显增高(P<0.05或0.01);急性冠状动脉综合征患者介入术后即刻CD62p、CD63和糖蛋白Ⅱb/Ⅲa受体复合物与术前相比明显增高(P<0.01),但术后24h较术前无明显变化(P>0.05)。与健康对照组和稳定型心绞痛组比,急性冠状动脉综合征组假血友病因子、内皮素1的表达水平明显增高(P<0.01),内皮依赖性血管舒张功能和一氧化氮降低(P<0.05或<0.01);急性冠状动脉综合征患者介入术后即刻血浆假血友病因子和内皮素1水平升高(P<0.05或P<0.01),内皮依赖性血管舒张功能和一氧化氮水平降低(P<0.05),且介入术后24h假血友病因子水平也较术前升高(P<0.05),内皮依赖性血管舒张功能降低(P<0.05),但内皮素1和一氧化氮水平与术前差异无显著性(P>0.05)。结论血小板活化和内皮功能的损伤在急性冠状动脉综合征发生和发展过程中起重要的作用,冠状动脉介入术后血管内皮受到一定损伤,血小板有一定程度的激活。     

脊柱复合性损伤的救治风险与早期治疗

目的评估脊柱复合性损伤的特点和救治风险,探讨风险控制与最佳治疗的方法。方法采用AIS、ISS、TRISS及APACHEⅡ等评分方法对273例脊柱复合性损伤患者进行定量评价与救治分类,并依据伤后的损伤分级、参数评定及计量评分等指标进行量化分析和统计处理。结果颈椎合并伤115例,胸椎合并伤141例,胸腰椎合并伤294例,腰骶椎合并伤181例;患者的救治风险和脊椎伤的治疗选择或手术时机与其合并伤的解剖伤势及由此所构成的整体伤情密切相关(P<0.01或<0.05);高风险性伤员往往综合伤势严重,生存概率(Ps)趋低,并发症和死亡率高(P<0.01或<0.05)。结论脊柱脊髓损伤常合并有严重的多发伤,高危伤情不仅可增加其救治风险和脊柱伤的处理难度,且还易于丧失手术最佳时机。分类救治对伤员的风险控制和脊柱伤的专科治疗是有益的。     

创伤性浮膝伴血管损伤的早期诊治

目的 探讨创伤性浮膝同时伴同侧血管损伤患者的早期诊断及救治.方法 总结1996年6月～2002年12月收治28例30个浮膝的手术固定方法、血管修复情况及术后治疗和恢复情况.结果 术后伤口一期愈合5例,17例伤口二期行植皮修复,4例胫前骨折部外露二期行皮瓣转移术,截肢2例,保肢成功率92.9%.术后26例经18个月～8年随访,骨折均愈合,下肢功能恢复优良率64.3%.结论 对浮膝损伤患者应高度重视伴有血管损伤可能,早期作出诊断,积极合理治疗,对患者预后至关重要.     

Prognostic index to identify patients who may not benefit from whole brain radiotherapy for multiple brain metastases from lung cancer

Palliative whole brain radiotherapy (WBRT) is often recommended in the management of multiple brain metastases. Allowing for WBRT waiting time, duration of the WBRT course and time to clinical response, it may take 6 weeks from the point of initial assessment for a benefit from WBRT to manifest. Patients who die within 6 weeks (‘early death’) may not benefit from WBRT and may instead experience a decline in quality of life. This study aimed to develop a prognostic index (PI) that identifies the subset of patients with lung cancer with multiple brain metastases who may not benefit from WBRT because of ‘early death’. The medical records of patients with lung cancer who had WBRT recommended for multiple brain metastases over a 10-year period were retrospectively reviewed. Patients were classified as either having died within 6 weeks or having lived beyond 6 weeks. Potential prognostic indicators were evaluated for correlation with ‘early death’. A PI was constructed by modelling the survival classification to determine the contribution of these factors towards shortened survival. Of the 275 patients recommended WBRT, 64 (23.22%) died within 6 weeks. The main prognostic factor predicting early death was Eastern Cooperative Oncology Group (ECOG) status >2. Patients with a high PI score (>13) were at higher risk of ‘early death’. Twenty-three per cent of patients died prior to benefit from WBRT. ECOG status was the most predictive for ‘early death’. Other factors may also contribute towards a poor outcome. With further refinement and validation, the PI could be a valuable clinical decision tool.