急性减压病大鼠肺组织粘附分子的变化

目的:探讨急性减压病大鼠肺组织中内粘附分子的改变。方法:雄性SD大鼠置于加压舱内,压缩空气在3 min内匀速加压至0.7 MPa,停留60 min后,3 min内快速减压出舱。观察减压后生存率、减压病症状。在减压后30 min、6 h、24 h取大鼠脑、肺及肝脏组织,甲醛溶液固定、切片、HE染色观测病理改变。免疫组化测定肺组织中细胞间粘附分子-1(ICAM-1)、E-选择素(E-selectin)、主要组织相容性复合体-Ⅱ(MHC-Ⅱ)的表达变化。在减压后6h、24 h前30 min,大鼠尾静脉注射2%evans blue溶液。30 min后行生理盐水灌注,收集肺组织,观测肺组织蓝染程度,酶标仪测定血浆中evans blue含量。结果:肺、肝及脑组织在减压后30 min出现水肿、淤血等病理表现。和正常组比较,肺组织中ICAM-1、E-selectin、MHC-Ⅱ在减压后明显上升,并呈现动态变化。相对于正常组,减压后6 h、24h肺组织血浆中evans blue含量明显增加。结论:气泡导致的,粘附分子介导的血管内皮受损是减压病的发病机制之一。     

高压氧预处理对减压病大鼠肺组织的影响

目的:研究高压氧预处理对减压病大鼠肺组织的影响及其意义。方法:SD大鼠30只,随机分为正常对照(CN)组,高压氧预处理(HBO)组,减压(DCS)组,减压组采用20min匀速升压至7.0ATA,停留20min使大鼠充分换气,2min内快速减压常压方案。减压24h后观察肺组织中谷胱甘肽过氧化物酶(GPx)、丙二醛(MDA)、超氧化物歧化酶(SOD)的变化;并通过HE染色观察肺组织病理学变化。结果:减压组肺泡腔不够完整,肺泡破裂融合,肺泡壁增厚,有中度炎性细胞浸润,高压氧组与减压组相比,病理改变明显减轻;与对照组相比,单纯减压使大鼠肺组织GPx、MDA升高,SOD降低,高压氧预处理组GPx、MDA降低,SOD降低升高;高压氧组与减压组相比GPx、MDA下降,SOD升高(P<0.05)。结论:高压氧预处理对减压病大鼠肺组织具有一定的保护作用。     

正常成年人口腔气流压的研究

本文研究了正常成人在鼓气、吮吸和吞咽时口腔气流压的变化情况。研究结果表明,正常成人吮吸时所需的最小口腔负压约—69mmHg,最大鼓气压为168mmHg。吞咽时口腔内有一个正负压变化过程,正压的范围为21mmHg～46mmHg,负压为-9mHg～-17mmHg。     

急性缺氧所致大鼠肺动脉内皮依赖性收缩反应

本实验初步证实,急性缺氧可使大鼠肺动脉产生内皮衍生收缩因子,并对其性质作了初步探讨。急性缺氧可使离体大鼠肺内和肺外动脉产生收缩反应,当灌流液氧分压从约17.3kPa降低到4kPa时(pH7.40～7.48),肺内和肺外动脉的基础张力分别比原来静息张力增加了37.5±5.1mg(n=4)和33.2±1.9mg(n=6);当氧分压恢复到约17.3kPa时,肺动脉基础张力也降到缺氧前的静息张力水平,即肺内动脉约300mg,肺外动脉约400mg。去掉内皮细胞后,急性缺氧引起的肺动脉收缩反应消失。消炎痛、去甲二氢愈创木脂酸、阿托品和酚妥拉明均不能阻断急性缺氧所致大鼠肺动脉内皮依赖性收缩反应。急性缺氧可诱发大鼠肺动脉内皮细胞产生释放非花生四烯酸环氧酶和脂氧酶代谢产物的内皮衍生收缩因子。     

主要生态环境变化对离体瘤胃菌丛降解粗纤维能力的影响

瘤胃微生物动物体外发酵是在模拟反刍动物瘤胃生态环境的装置中进行的 .用长期在动物体外培养和筛选、继代的瘤胃菌丛 90 52 3 1在人工瘤胃装置中研究主要生态条件变化对其降解粗纤维能力的影响 ,发现在温度 30～ 40℃ ,扰动 60～ 72r·min- 1 、2 0min·h- 1 和底物C/N比为 1 0 /1的生态条件下分解粗纤维的能力最强 .发酵 5d可达到纤维分解率 36～ 41 %的水平 .     

负压封闭引流技术治疗蛇伤骨筋膜室综合征体会

目的观察负压封闭引流(vacuum sealing drainage,VSD)技术治疗蛇伤骨筋膜室综合征的临床疗效。方法对我院2014年1月始应用VSD技术治疗蛇伤骨筋膜室综合征患者17例的临床资料进行回顾性分析。结果 13例沿筋膜纵轴方向充分切开减压,4例行多筋膜间隔联合大切口减压。17例患者均出现不同程度的局部组织坏死,5例出现遗留功能障碍,无创面感染及截肢病例。结论封闭负压引流技术可减少蛇咬伤毒素吸收,降低感染、坏死几率,改善患者临床症状,有效防止蛇伤骨筋膜室综合征的发展。     

腺苷抗豚鼠室性心律失常的电生理研究

实验用全细胞膜片钳技术在单个豚鼠心室肌细胞上研究了腺苷 (Ado)对正常及异丙肾上腺素 (Iso)致豚鼠心室肌细胞动作电位、迟后除极 (DAD)、L 型钙电流 (ICa.L)和短暂内向电流 (Iti)的作用。结果表明 :(1)Ado在2 0～ 10 0 μmol/L时对豚鼠心室肌细胞动作电位和ICa .L无明显直接作用 ,但却可明显降低Iso所致的动作电位时程(APD)延长和ICa .L峰值增大 ,Iso (10nmol/L)使细胞APD50 从 3 40± 2 1ms延长到 486± 2 8ms (P <0 0 1) ,APD90从 3 61± 17ms延长至 5 0 1± 2 9ms (P <0 0 1) ;ICa .L峰值从 - 6 5 3± 1 4pA/pF增大到 - 18 2 8± 2 4pA/pF (P <0 0 1) ,电流电压曲线明显左移和下移 ;Ado (5 0 μmol/L)使APD50 和APD90 降至 40 3± 19ms和 419± 2 6ms ,但并不影响动作电位其它参数 ,使ICa.L峰值降低至 - 10 2± 1 5pA/pF (P <0 0 1)。 (2 )Iso (3 0nmol/L)可诱发心室肌细胞产生DADs,其发生率为 10 0 % ;Ado (5 0 μmol/L)可完全抑制Iso引发DADs;细胞经 - 40～ +2 0mV、时程 2s的除极电压 ,Iso (3 0nmol/L)诱导出Iti,其发生率为 10 0 % ;Ado (5 0 μmol/L)可明显抑制Iso致Iti的发生 ,其发生率降为 14 3 %。研究结果提示 ,Ado对豚鼠心室肌细胞动作电位和ICa.L无明显直接作用 ,但却可显著降低Is     

有空中晕厥史飞行人员的下体负压耐力及其心血管系统反应特点

本文通过观察有空中晕厥史及健康飞行人员对坐位下体负压的耐力及其心血管系统反应特点,证实了-50mmHg的下体负压强度已能够检测出空中晕厥组与健康组飞行人员耐力上的明显差异。在-50mmHg负压强度作用下,被检人员心血管系统功能状态发生了明显的变化;特别是暴露的2～4分钟,心率、血压、SV、EF、HI的变化,组间有明显差别。此外,STI和ECG各参数亦有明显变化,但组间差异尚不显著。     

红核脊髓运动诱发电位与脊髓损伤的关系

目的: 探讨一种可以敏感地反映脊髓损伤程度的客观、定量的电生理学指标.方法: 采用Wrathall等人描述的重力损伤法制备大鼠脊髓胸段(T8)分级损伤模型,通过测量损伤动物红核-脊髓运动诱发电位(MEPs)的变化,并与动物运动行为和组织形态学检查结果进行比较,分析红核-脊髓MEPs与脊髓分级损伤的关系.结果: 在给予红核刺激后,假损伤组红核-脊髓MEPs出现5～7个正波和4～5个负波,峰-峰总幅度值(简称总峰值)为(195.25±34.35)μV,峰潜伏时为(1.57±0.15)ms.随损伤程度加大,总峰值明显减少,而峰潜伏时明显延长.红核-脊髓MEPs总峰值与观察期末的BBB评分(r=0.79)以及损伤中心处的残余面积(r=0.87)显著相关;峰潜伏时与观察期末的BBB评分(r=-0.88)以及损伤中心处的残余面积(r=-0.86)也有显著的相关性.结论: 红核-脊髓MEPs总峰值和峰潜伏时两项指标可以敏感地反映脊髓分级损伤程度、运动功能和形态学情况,是监测胸段脊髓损伤程度的客观、定量、精细的电生理指标.     

羊耳菊提取物主要活性成分在大鼠体内的组织分布研究

为了研究大鼠灌胃羊耳菊提取物后7个指标成分在体内的组织分布情况,实验建立同时测定大鼠组织中4,5-二咖啡酰基奎宁酸、新绿原酸、绿原酸、3,4-二咖啡酰基奎宁酸、1,3-二咖啡酰基奎宁酸、隐绿原酸、木犀草苷的UPLC-MS/MS方法,将羊耳菊提取物灌胃给予SD大鼠,分别于给药0. 5、1. 5、5 h取其主要脏器和组织,采用UPLC-MS/MS测定各时间点下7个指标成分在脏器和组织中的分布情况。大鼠灌胃羊耳菊提取物后,对于新绿原酸,其浓度0. 5 h在小肠、肾、肺、肝达到峰值; 1. 5 h在胃、肌、脾达到峰值; 5 h在心达到峰值。对于绿原酸,其浓度0. 5 h在小肠、肾、肺、心达到峰值; 1. 5 h在胃、肌、脾、肝达到峰值。对于隐绿原酸,其浓度0. 5 h在小肠、肾、肺达到峰值; 1. 5 h时在心、肝、脾、肺、胃达到峰值。对于1,3-二咖啡酰基奎宁酸,其浓度0. 5 h在心、肺、肾、小肠达到峰值; 1. 5 h在肝、脾、肌、胃达到峰值。对于3,4-二咖啡酰基奎宁酸,其浓度0. 5 h在小肠和肾达到峰值; 1. 5 h在肝、脾、肌、胃达到峰值; 5 h在心、肺达到峰值。对于4,5-二咖啡酰基奎宁酸,其浓度0. 5 h在小肠、肾、心达到峰值; 1. 5 h在肝、脾、肌、胃达到峰值; 5 h在肺达到峰值。对于木犀草苷,其浓度0. 5h在小肠和心达到峰值; 1. 5 h在肝、脾、胃达到峰值; 5 h在肺和肾达到峰值。7个指标成分可迅速、广泛地分布在各组织器官中,脑组织中未检测到该7种成分。7种成分主要分布在胃、小肠和肾组织中,对肾脏表现出较强的亲和力,推测肾脏可能是羊耳菊的主要排泄器官之一。     

Characterization of the response to primary blast injury

Lung injuries, predominantly arising from blast exposure, are a clinical problem in a significant minority of current military casualties. This special feature consists of a series of articles on lung injury. This first article examines the mechanism of the response to blast lung (primary blast injury to the lung). Subsequent articles examine the incidence of blast lung, clinical consequences and current concepts of treatment, computer (in silico) modelling of lung injury and finally chemical injuries to the lungs. Blast lung is caused by a shock wave generated by an explosion causing widespread damage in the lungs, leading to intrapulmonary haemorrhage. This, and the ensuing inflammatory response in the lung, leads to a compromise in pulmonary gas exchange and hypoxia that can worsen over several hours. There is also a characteristic cardio-respiratory effect mediated via an autonomic reflex causing apnoea (or rapid shallow breathing), bradycardia and hypotension (the latter possibly also due to the release of nitric oxide). An understanding of this response, and the way it modifies other reflexes, can help the development of new treatment strategies for this condition and for the way it influences the patient's response to concomitant injuries.     

Prediction of globe rupture caused by primary blast: a finite element analysis

Although a human eye comprises less than 0.1% of the frontal body surface area, injuries to the eye are found to be disproportionally common in survivors of explosions. This study aimed to introduce a Lagrangian–Eulerian coupling model to predict globe rupture resulting from primary blast effect. A finite element model of a human eye was created using Lagrangian mesh. An explosive and its surrounding air domain were modelled using Eulerian mesh. Coupling the two models allowed simulating the blast wave generation, propagation and interaction with the eye. The results showed that the peak overpressures caused by blast wave on the corneal apex are 2080, 932.1 and 487.3 kPa for the victim distances of 0.75, 1.0 and 1.25 m, respectively. Higher stress occurred at the limbus, where the peaks for the three victim distances are 25.5, 14.1 and 6.4 MPa. The overpressure threshold of globe rupture was determined as 2000 kPa in a small-scale explosion. The findings would provide insights into the mechanism of primary blast-induced ocular injuries.     

Modeling of weak blast wave propagation in the lung

Blast injuries of the lung are the most life-threatening after an explosion. The choice of physical parameters responsible for trauma is important to understand its mechanism. We developed a one-dimensional linear model of an elastic wave propagation in foam-like pulmonary parenchyma to identify the possible cause of edema due to the impact load. The model demonstrates different injury localizations for free and rigid boundary conditions. The following parameters were considered: strain, velocity, pressure in the medium and stresses in structural elements, energy dissipation, parameter of viscous criterion. Maximum underpressure is the most suitable wave parameter to be the criterion for edema formation in a rabbit lung. We supposed that observed scattering of experimental data on edema severity is induced by the physiological variety of rabbit lungs. The criterion and the model explain this scattering. The model outlines the demands for experimental data to make an unambiguous choice of physical parameters responsible for lung trauma due to impact load.     

The epidemiology of blast lung injury during recent military conflicts: a retrospective database review of cases presenting to deployed military hospitals, 2003-2009

Blast injuries are becoming increasingly common in military conflicts as the nature of combat changes from conventional to asymmetrical warfare and counter-insurgency. This article describes a retrospective database review of cases from the UK joint theatre trauma registry from 2003 to 2009, containing details of over 3000 patients, mainly injured in Iraq and Afghanistan. During this period, 1678 patients were injured by explosion of whom 113 had evidence of blast lung injury. Of the 50 patients who survived to reach a medical facility, 80 per cent required ventilatory support. Injuries caused by explosion are increasing when compared with those caused by other mechanisms, and blast lung represents a significant clinical problem in a deployed military setting. Management of these patients should be optimized from point of wounding to definitive care.     

Local Government Reform and the Health Services

The shock wave generated by an explosion (“blast wave”) may cause injury in any or all of the following: (1) direct impact on the tissues of variations in environmental pressure; (2) flying glass and other debris set in motion by it; (3) propulsion of the body. Injuries in the first category affect gas-containing organs (ears, lungs and intestines), and acute death is attributed to air forced into the coronary vessels via damaged pulmonary alveoli. It is estimated that overpressure sufficient to cause lung injury may occur up to five miles from a 20-megaton nuclear explosion. The greatest single hazard from blast is, however, flying glass, and serious wounding from this cause is possible up to 12 miles from an explosion of this magnitude.     

Blast injury research models

Blast injuries are an increasing problem in both military and civilian practice. Primary blast injury to the lungs (blast lung) is found in a clinically significant proportion of casualties from explosions even in an open environment, and in a high proportion of severely injured casualties following explosions in confined spaces. Blast casualties also commonly suffer secondary and tertiary blast injuries resulting in significant blood loss. The presence of hypoxaemia owing to blast lung complicates the process of fluid resuscitation. Consequently, prolonged hypotensive resuscitation was found to be incompatible with survival after combined blast lung and haemorrhage. This article describes studies addressing new forward resuscitation strategies involving a hybrid blood pressure profile (initially hypotensive followed later by normotensive resuscitation) and the use of supplemental oxygen to increase survival and reduce physiological deterioration during prolonged resuscitation. Surprisingly, hypertonic saline dextran was found to be inferior to normal saline after combined blast injury and haemorrhage. New strategies have therefore been developed to address the needs of blast-injured casualties and are likely to be particularly useful under circumstances of enforced delayed evacuation to surgical care.     

Chest response assessment of post-mortem swine under blast loadings

To better protect soldiers from blast threat, that principally affect air-filled organs such a lung, it is necessary to develop an adapted injury criterion and, prior to this, to evaluate the response of a biological model against that threat. The objective of this study is to provide some robust data to quantify the chest response of post-mortem swine under blast loadings.7 post-mortem swine (54.5 ± 2.6 kg), placed side-on to the threat and against the ground, were exposed to 5 shock-waves of increasing intensities. Their thorax were instrumented with a piezo-resistive pressure sensor, an accelerometer directly exposed to the shock-wave and a target was mounted on the latter in order to track the chest wall displacement.For incident impulses ranging from 47 kPa ms ± 2% to 173 kPa ms ± 6%, the measured maximum of linear chest wall acceleration (Γmax) goes from 5800 m/s² ± 16% to 41,000 m/s² ± 8%, with a duration of 0.8 ms. Chest wall displacements ranging from 5 mm ± 20% to 20 mm ± 15%, with a duration of 9 ms, are reached. These reproducible data were used to find simple relations (linear, 2nd and 3rd order polynomials) between the kinematic parameters (plus the viscous criterion) and the incident and reflected impulses.Correlating the new reproducible data with the prediction from the Bowen curves showed a lung injury threshold in terms of Γmax similar to that of Cooper (10,000 m/s²). However, the limits defined for the viscous criterion in the automobile field and for non-lethal weapons seems not adapted for the blast threat.     

Blast injuries to the lung: epidemiology and management

Lung injury is frequently a component of the polytrauma sustained by military personnel surviving blast on the battlefield. This article describes a case series of the military casualties admitted to University Hospital Birmingham's critical care services (role 4 facility), during the period 1 July 2008 to 15 January 2010. Of the 135 casualties admitted, 107 (79.2%) were injured by explosive devices. Plain chest films taken soon after arrival in the role 4 facility were reviewed in 96 of the 107 patients. In 55 (57.3%) films a tracheal tube was present. One or more radiological abnormalities was present in 66 (68.75%) of the films. Five patients met the consensus criteria for the definition of adult respiratory distress syndrome (ARDS). The majority of casualties with blast-related lung injury were successfully managed with conventional ventilatory support employing a lung protective strategy; only a small minority received non-conventional support at any time in the form of high-frequency oscillatory ventilation. Of those casualties who survived to be received by the role 4 facility, none subsequently died as a consequence of lung injury.     

Numerical simulation of wave propagation in a realistic model of the human external ear

In this study, a numerical investigation is performed to evaluate the effects of high-pressure sinusoidal and blast wave's propagation around and inside of a human external ear. A series of computed tomography images are used to reconstruct a realistic three-dimensional (3D) model of a human ear canal and the auricle. The airflow field is then computed by solving the governing differential equations in the time domain using a computational fluid dynamics software. An unsteady algorithm is used to obtain the high-pressure wave propagation throughout the ear canal which is validated against the available analytical and numerical data in literature. The effects of frequency, wave shape, and the auricle on pressure distribution are then evaluated and discussed. The results clearly indicate that the frequency plays a key role on pressure distribution within the ear canal. At 4 kHz frequency, the pressure magnitude is much more amplified within the ear canal than the frequencies of 2 and 6 kHz, for the incident wave angle of 90° investigated in this study, attributable to the ‘4-kHz notch’ in patients with noise-induced hearing loss. According to the results, the pressure distribution patterns at the ear canal are very similar for both sinusoidal pressure waveform with the frequency of 2 kHz and blast wave. The ratio of the peak pressure value at the eardrum to that at the canal entrance increases from about 8% to 30% as the peak pressure value of the blast wave increases from 5 to 100 kPa for the incident wave angle of 90° investigated in this study. Furthermore, incorporation of the auricle to the ear canal model is associated with centerline pressure magnitudes of about 50% and 7% more than those of the ear canal model without the auricle throughout the ear canal for sinusoidal and blast waves, respectively, without any significant effect on pressure distribution pattern along the ear canal for the incident wave angle of 90° investigated in this study.     

爆炸波对生物膜微观创伤的分子动力学分析

爆炸冲击波作用到人体胸部时,肺部会出现肺出血及肺水肿等症状,这是人体爆炸创伤的主要原因,深入研究很有必要.为了更好地理解爆炸创伤的机理,应研究冲击波与微观组织作用的力学过程,但具有一定的难度.本文从基本的生物膜做起,运用分子动力学研究冲击波对DPPC膜造成的损伤,通过停止活塞来控制冲击波的冲量,观察冲击过程中膜的恢复情况.通过观察不同冲量下冲击波经过膜后磷脂分子及其周围水分子分布,发现随着冲量增大,膜越来越无序混乱,褶皱更严重,疏水区水分子越来越多.将膜冲击过程划为3个阶段,分别为冲击阶段、恢复阶段和后效阶段.发现当冲量大于153 m Pa·s时,在冲击过程中没有观察到膜的损伤恢复.