当归挥发油对大鼠局灶性脑缺血再灌注损伤的保护作用

目的: 探讨当归挥发油对大鼠局灶性脑缺血再灌注损伤的保护作用。方法: 采用改良线栓法阻断大鼠大脑中动脉建立脑缺血模型,到达再灌注时限后进行神经功能缺损评分;检测脑梗死体积比、脑含水量及脑血管通透性;血清NO、NOS含量;以及SOD和GSH-Px活性。结果: 当归挥发油可有效改善脑缺血再灌注损伤大鼠的神经功能缺损;降低脑梗死体积比、脑血管通透性和脑含水量;降低血清 NO、NOS含量; 增强SOD和GSH-Px活性。结论: 当归挥发油对脑缺血再灌注损伤有显著保护作用,其机制可能与提高脑组织抗氧化能力有关。     

外源性血管内皮衍生超极化因子对脑缺血再灌注损伤的影响

目的: 硫化氢(hydrogen sulfide, H₂S)为一种假定的血管内皮衍生超极化因子(endothelium- derived hyperpolarizing factor, EDHF),本研究探讨外源性H₂S,即外源性假定的EDHF对脑缺血再灌注损伤的影响。方法: 采用线栓法复制大鼠局灶性脑缺血(MCAO)再灌注损伤模型,测定动物行为功能、脑组织梗死体积、脑组织含水量、血清乳酸脱氢酶(LDH)活性及丙二醛(MDA)含量,用HE染色法观察脑组织学改变。结果: H₂S供体硫氢化钠(NaHS, i.v.) 0.195、0.390、0.780 mg/kg 能明显改善神经功能状态,降低缺血再灌注后脑梗死体积百分比,降低脑含水量,显著地抑制局灶性脑缺血再灌注损伤大鼠血清MDA含量和LDH活性,并不同程度地改善大鼠脑病理组织学的变化。结论: NaHS可明显改善大鼠脑缺血再灌注性损伤,提示外源性EDHF (H₂S)有抗脑缺血再灌损伤作用。     

面向年龄和车辆前部差异的行人下肢交通损伤

行人的交通损伤多发生在下肢且损伤程度与车辆前部外形相关。为揭示车辆前端结构造成行人下肢损伤的差异成因并确定此类损伤的机理,根据中国人体特征和骨骼材料特性建立了不同年龄的下肢模型,并结合车辆前部结构特征模拟了正面碰撞,分析了年龄、车辆前部结构与下肢损伤的定量关系。结果表明,年龄差异会造成显著的关节损伤差异;汽车前围结构影响行人下肢损伤的部位,且较小的离地间隙和较宽的前围造成的下肢损伤较小。     

基于车辆-行人碰撞颅脑伤防护的参数研究

研究了汽车行驶速度及前部结构各设计参数对行人颅脑损伤的影响，讨论了颅脑损伤防护的可行性措施。运用多刚体动力学软件Madymo建立了基于不同车型参数的汽车前部结构数学模型以及行人人体数学模型，进行了车辆-行人碰撞的计算机仿真，并对仿真结果进行了分析研究。研究表明，汽车行驶速度、发动机盖盖沿高度以及发动机盖和挡风玻璃的刚度等参数对行人颅脑损伤影响显著。     

汽车低速追尾碰撞中乘员动力学响应和颈部损伤的仿真研究

利用MADYMO仿真分析软件建立了包括BioRIDⅡ假人、座椅和安全带在内的追尾碰撞模型，研究了在追尾碰撞中，座椅特性和乘员位置对乘员动力学响应和颈部损伤的影响。仿真分析结果表明，头枕位置、靠背刚度、靠背倾角调节器特性和乘员乘坐姿势对乘员头颈部的动力学响应有很大影响，通过合理的座椅设计可以显著降低颈部损伤风险。     

Drug use and fatal motor vehicle crashes: A case-control study

Drugged driving is a serious safety concern, but its role in motor vehicle crashes has not been adequately studied. Using a case-control design, the authors assessed the association between drug use and fatal crash risk. Cases (n = 737) were drivers who were involved in fatal motor vehicle crashes in the continental United States during specific time periods in 2007, and controls (n = 7719) were participants of the 2007 National Roadside Survey of Alcohol and Drug Use by Drivers. Overall, 31.9% of the cases and 13.7% of the controls tested positive for at least one non-alcohol drug. The estimated odds ratios of fatal crash involvement associated with specific drug categories were 1.83 [95% confidence interval (CI): 1.39, 2.39] for marijuana, 3.03 (95% CI: 2.00, 4.48) for narcotics, 3.57 (95% CI: 2.63, 4.76) for stimulants, and 4.83 (95% CI: 3.18, 7.21) for depressants. Drivers who tested positive for both alcohol and drugs were at substantially heightened risk relative to those using neither alcohol nor drugs (Odds Ratio = 23.24; 95% CI: 17.79, 30.28). These results indicate that drug use is associated with a significantly increased risk of fatal crash involvement, particularly when used in combination with alcohol.     

Injury incidence rates of cyclists compared to pedestrians,car occupants and powered two-wheeler riders,using a medical registry and mobility data,Rhône County,France

Purpose

In France, the bicycle's modal share is stabilizing after a decline; in some of France's major cities, it has even increased since the 1990s. It is hence relevant to improve the knowledge of the injury risk associated with cycling, compared with other means of transport such as car, walking and powered two-wheeler (PTW) riding.

Methods

The injury incidence rates were estimated by the ratio between accident data and mobility (exposure) data. Two accident data sources were used: police data and hospital-based data (outpatients and inpatients) from the Rhône road trauma Registry. This provides four injury categories: all-injury, hospitalization, serious-injury and fatal-injury. Exposure data were estimated from a regional household travel survey (RTS), using three measures of mobility: number of trips, distance traveled and time spent traveling. The survey was carried out from November 2005 to April 2006, on weekdays, outside school and public holidays; this seasonality was corrected using the 2007–2008 national household travel survey (NTS) that covered an entire year. Only information involving accidents and trips in, and residents of, the Rhône County (1.6 million inhabitants, including the city Lyon) were included in our study. Trends of injury rates were also evaluated in Greater Lyon, using previous travel surveys.

Results

The PTW riders had the highest all-injury, hospitalization, serious-injury and fatal-injury rates, followed by cyclists, and lastly by pedestrians and car occupants. The rates between men and women seemed similar among pedestrians and among car occupants. For car occupants, pedestrians and cyclists, the age group 18–25 years had higher all-injury rate compared with the age group 25–65 years. On the contrary, the age group ≥65 years seemed to have higher hospitalization and serious-injury rates, compared with the age group 25–65 years. For cyclists, the injury rates seemed higher in non-dense areas than in dense areas. Between 1996–1997 and 2005–2006 and with regards to time spent traveling, the all-injury, serious-injury and fatal-injury rates seemed to have decreased for car occupants and cyclists.

Conclusion

The higher risk for PTW riders is confirmed and quantified; it is very high. Decrease in injury rates seems more marked for cyclists; this may indicate the “safety in numbers” effect. Countermeasures for improving road safety could be implemented, especially for vulnerable road user types. However, they will not be sufficient to fill in the gap between the much higher risk for PTW riders and that of car occupants. Exposure-based injury rates can be a tool for monitoring and evaluating the effectiveness of policies and programs, and for comparisons between countries.     

Angular Impact Mitigation system for bicycle helmets to reduce head acceleration and risk of traumatic brain injury

Angular acceleration of the head is a known cause of traumatic brain injury (TBI), but contemporary bicycle helmets lack dedicated mechanisms to mitigate angular acceleration. A novel Angular Impact Mitigation (AIM) system for bicycle helmets has been developed that employs an elastically suspended aluminum honeycomb liner to absorb linear acceleration in normal impacts as well as angular acceleration in oblique impacts. This study tested bicycle helmets with and without AIM technology to comparatively assess impact mitigation. Normal impact tests were performed to measure linear head acceleration. Oblique impact tests were performed to measure angular head acceleration and neck loading. Furthermore, acceleration histories of oblique impacts were analyzed in a computational head model to predict the resulting risk of TBI in the form of concussion and diffuse axonal injury (DAI). Compared to standard helmets, AIM helmets resulted in a 14% reduction in peak linear acceleration (p < 0.001), a 34% reduction in peak angular acceleration (p < 0.001), and a 22–32% reduction in neck loading (p < 0.001). Computational results predicted that AIM helmets reduced the risk of concussion and DAI by 27% and 44%, respectively. In conclusion, these results demonstrated that AIM technology could effectively improve impact mitigation compared to a contemporary expanded polystyrene-based bicycle helmet, and may enhance prevention of bicycle-related TBI. Further research is required.     

Albumin Infusion in Critically Ill COVID-19 Patients: Hemodilution and Anticoagulation

Hypercoagulation is one of the major risk factors for ICU treatment, mechanical ventilation, and death in critically ill patients infected with SARS-CoV-2. At the same time, hypoalbuminemia is one risk factor in such patients, independent of age and comorbidities. Especially in patients with severe SARS-CoV-2-infection, albumin infusion may be essential to improve hemodynamics and to reduce the plasma level of the main marker of thromboembolism, namely, the D-dimer plasma level, as suggested by a recent report. Albumin is responsible for 80% of the oncotic pressure in the vessels. This is necessary to keep enough water within the systemic circulatory system and for the maintenance of sufficient blood pressure, as well as for sufficient blood supply for vital organs like the brain, lungs, heart, and kidney. The liver reacts to a decrease in oncotic pressure with an increase in albumin synthesis. This is normally possible through the use of amino acids from the proteins introduced with the nutrients reaching the portal blood. If these are not sufficiently provided with the diet, amino acids are delivered to the liver from muscular proteins by systemic circulation. The liver is also the source of coagulation proteins, such as fibrinogen, fibronectin, and most of the v WF VIII, which are physiological components of the extracellular matrix of the vessel wall. While albumin is the main negative acute-phase protein, fibrinogen, fibronectin, and v WF VIII are positive acute-phase proteins. Acute illnesses cause the activation of defense mechanisms (acute-phase reaction) that may lead to an increase of fibrinolysis and an increase of plasma level of fibrinogen breakdown products, mainly fibrin and D-dimer. The measurement of the plasma level of the D-dimer has been used as a marker for venous thromboembolism, where a fourfold increase of the D-dimer plasma level was used as a negative prognostic marker in critically ill SARS-CoV-2 hospitalized patients. Increased fibrinolysis can take place in ischemic peripheral sites, where the mentioned coagulation proteins can become part of the provisional clot (e.g., in the lungs). Although critically ill SARS-CoV-2-infected patients are considered septic shock patients, albumin infusions have not been considered for hemodynamic resuscitation and as anticoagulants. The role of coagulation factors as provisional components of the extracellular matrix in case of generalized peripheral ischemia due to hypoalbuminemia and hypovolemia is discussed in this review.     

颅脑撞击损伤的三维有限元模型

通过一系列有效的简化和假设,建立颅脑的三维有限元模型,研究运动着的颅脑撞到静止物上时脑内响应,即颅脑减速损伤.得到了脑区的应力云图,清晰地反应出脑组织内的应力波传播和扩散过程,验证了当头部受到减速撞击时,损伤不仅仅发生在受撞击的局部,且会在应力波的传播方向发生更为严重、更为广泛的对冲性损伤.结果与已有文献及临床医学相符.