The changes of succinate dehydrogenase (SDH) activity and the transmem-brane potential at areas 0.5, 2, and 3 cm away from the wound track respectively of the hind legs of 6 dogs in the 1st and 6th hour after injury with high velocity bullets (5.56mm) were studied.It was found that both the SDH activity and transmembrane potential lowered significantly and continuously in the 0.5 cm area. In the 2 cm area, the SDH sctivity was maintained at a low level, and the changes of the transmembrane potential were not remarkable. In the 3 cm area, both the SDH activity and transmembrane potential showed no obvious changes.The results suggest that the assay of the SDH activity of the injured muscles proves to be an effective and reliable method to predict the viability of muscles

The war injuries with seawater immersion has become one of the most common in the naval battle. These injuries are quite different on characteristics from simple war injuries because of the low temperature, high osmotic pressure and bring a large number of bacterial of seawater. The characteristics and early treatment of war injuries with seawater immersion were introduced on research results of army medicine order task. The significance of making a thorough investigation and study was discussed.

BACKGROUND:It has been reported that blast wave and haze can lead to hemodynamics disturbance.However,studies on blast-haze combined injury on hemodynamics changes are few.OBJECTIVE:To investigate the effect of blast-haze on the hemodynamics parameters during early period following cabin explosion,additionally,to evaluate the feasibility of brain natriuretic polypeptide(BNP) to serve as the damage criterion in early detection.DESIGN,TIME AND SETTING:Randomization,experimental observation of animal was performed at the Research Institute of Surgery,Daping Hospital,Third Military Medical University between August 2006 and August 2007.MATERIALS:One hundred and four healthy,male SD rats were randomly divided into the normal control(n=8),blast injury(n=48),and combined injury(n=48) groups.METHODS:The rats were fixed in the cabin according to the position of the war sitting,0.4 g cyclotrimethylene trinitramine were used to explosion in the centre of the cabin.The rats in the blast injury and combined injury group were took out immediately and 100 s after explosion,respectively.No treatment was performed in the normal control group.MAIN OUTCOME MEASURES:The heart function changes,the level of BNP,as well as the pathological change of lung tissues were analyzed by ELISA,double antibody sandwich method,and the microscope at 1,3,6,12,24,and 72 hours after injury,respectively.RESULTS:Compared with the normal control group,there were significantly differences of pathomorphological changes in the blast injury and combined injury groups,even,more severe in the combined group than the blast injury group.The level of BNP at each time point was higher than that of the normal control group(P

Objective To study the effect of neuropeptide on migration of epidermal stem cells in wound repair. Methods 90 new born rats (3～4d old) were randomly divided into three groups: SP group, capsaicin group, and normal group. BrdU labeling, combined with specific protein markers of epidermal stem cells, K19 and ?1 integrin, were used to identify epidermal stem cells. The migration of epidermal stem cells was observed in full thickness skin wound on back on 21 days after injury. Substance P was applied to the skin wound after injury in SP group. The status of migration of epidermal stem cells in SP group was compared with that in capsaicin group, in which capsaicin was injected to destroy sensory neuron before skin injury, and with normal group, in which the skin wound was not treated with any medication. Results Wounds of rats in SP group were healed 18 days after injury. It was shortened by three days compared with normal group. Only 25.54% of wound area was healed in capsaicin group on day 18. There were many epidermal stem cells in the edge of the wound and granulation tissue in Group SP. Only a small number of epidermal stem cells were seen in capsaicin group, where SP release was blocked by chemical destruction of sensory neurons, in the wound edge, but not in granulation tissue. The amount of epidermal stem cells as seen in the wound edge, but not in granulation tissue, in normal group was less than in the SP group but more than in capsaicin group. Conclusions SP obviously promotes wound healing and shortens the healing period. SP can induce epidermal stem cells to migrate into the skin wound edge and granulation tissue.

Objective A dog model of blast-burn combined injuries followed by immersion in seawater was reproduced in dog to study hemodynamic responses and their mechanism. Methods The dogs which were exposed to blast injuries produced by primer explosion and 10% second degree burn were randomly divided into seawater immersion group and blast-burn only group. The dogs in immersion group were immersed in seawater under anesthesia for 4 hours. The hemodynamics of the dogs was monitored, and blood samples were collected to assay malondialdehyde (MDA), and cultured for bacteria. After the above procedures were completed, the pathological changes in the dogs′ hearts and lungs were observed. The dogs in blast-burn group underwent the same protocol in immersion group except immersion. Results The body temperature (T), cardiac index (CI), mean arterial pressure (MAP), and heart rate (HR) in dogs in the immersion group were remarkably decreased, while the mean pulmonary artery pressure (MPAAP), systemic vascular resistance index (SVRI), and pulmonary vascular resistance index (PVRI) were markedly increased compared with those in blast-burn group. These obvious hemo dynamic disorders occurred during 3h to 6h after the dogs leaving seawater. Plasma MDA level was negatively correlated with CI. The interval between positive blood calture for intestinal bacteria and injury was shorter in immersion group than that of blast-burn group. The gross and histopathological changes in dogs′ hearts and lungs in immersion group injuries were more severe in degree than in blast-burn group. Conclusions Seawater immersion markedly aggravates the hemodynamic disorders in dogs having had blast-burn combined injury. The changes became obvious during 3h to 6h after leaving seawater. The aggravating effect might be related with declination of body temperature, inflammatory response and lipid peroxidation.

Objective To evaluate the mortality and survival time of war injuries, followed by seawater immersion. Methods Animal models of injuries including open chest injury, open abdominal injury, burn, hemorrhagic shock, were reproduced. The animals were divided into two groups: control group consisting simple injury without seawater immersion, and seawater immersion group consisting similar injuries followed by seawater immersion. The survival time of animals of the two groups were recorded. Results The mean survival time of the animals with open chest injury and open abdominal injury followed by seawater immersion was 45 minutes and 162 minutes, respectively. The mortality of 30% Ⅱ degree burn was 50% after seawater immersion for 4 hours, while it was 6% without seawater immersion. The mortality of moderate hemorrhagic shock with four-hour with seawater immersion was 90%, while all the animals survived without seawater immersion. Conclusions The experimental study showed that the mortality rate was significantly raised and the survival time significantly shortened when open wounds were exposed to seawater for a certain period of time. Hypertonicity of the seawater with high sodium content, and low temperature of seawater might play important roles in producing various pathophysiological changes which contributed to early death of the animals.

Objective To approach the relationship between visceral histopathology and blood bacteriology changes of projectile-burn combined wound jointed with seawater soak. Methods After model creation in dogs of projectile-burn combined wound jointed with seawater soak, fifteen dogs were randomly assigned randomized into two groups: projectile-burn-only(unsoaked group, US), projectile-burn combined wound with seawater immersion(soaked group,S). 0, 4,7,10,20,28h after injury the blood samples were taken for bacterial culture. Tissue samples of heart, liver, kidneys were taken for pathological examination with light microscope (LM) 28h after injury or in the moribund stage. Results Bacteriemia was found in soaked group earlier and severer.The bacteriemia has a multiple sources. There were not only intestinal bacteria, but also surface bacteria and seawater bacteria found in soaked group. Different degrees of circulation disturbance, degeneration changes and severe inflammation reaction were found in viscera. Conclusion After seawater soak, bacteriemia aggravated the injury of animals′ viscera, and thus led to a higher mortality.

In the future,anti-ship missiles(ASM) will be major weapons in the sea war.It is very important to handle the profile of the casualties aboard warships attacked by ASM for development of naval health service.The statistical result shows there is a greater chance of casualties but less chance of warships being sunken by ASM.Besides,medical staffs should pay more attention to the first aid for victims due to blast,burn,smoke inhalation and penetration while the danger of the sea water immersion should not be ignored.

AIM: To study the phosphatidylinositol metabolism of vascular endothelial cells exposed to projectile's pressure wave METHODS: The cultured endothelial cells were exposed to bullet's pressure wave as experimental model. The intracellular inositol-1,4,5-triphosphate(IP_3), intracellular free calcium ([Ca 2+ ]i), protein kinase C(PKC) and lactate dehydrogenase (LDH) activities in cultural medium were assayed after the cultured cells exposed to bullet's pressure wave. After blocking phosphatidylinositol metabolism with neomycin, the above biochemical parameters of cells exposed to bullet's pressure wave were also measured. RESULTS: Bullet's pressure wave induced increase in the intracellular IP_3, [Ca 2+ ]i, and PKC activity obviously. The change of LDH activity paralleled with above biochemical changes. Blocking phosphatidylinositol metabolism partially inhibited these changes. CONCLUSION: Bullet's pressure wave may activate phosphatidylinositol metabolism, which may trigger the injury to the endothelial cells and lead to leakage of plasmatic LDH.

Objective To study the influence of seawater immersion on hemostatic function after burn in dogs. Methods Twenty healthy adult mongrel dogs of beth sexes weighing 12-15 kg were randomly divided into two groups: immersion group(n=10) and control group(n=10). The animals were anesthestized with 3% pentobarbital 30 mg?kg~(-1) i.v., intubated and mechanically ventilated. 5F Swan-Ganz catheter was placed via right internal jugular vein. 10% of the skin on the back was burnt(second degree). In immersion group the animals were immersed in seawater containing salt 25.3 g?L~(-1)(pH8.1, T21-23℃) with head and neck kept above water for 4h. In control group the animals suffered second degree burn of same area without being immersed in seawater. Blood samples were taken from Swan-Ganz catheter before burn(baseline)and 4,7,10,20,28 h after burn for determination of(1) circulating endothelial cell(CEC) count, (2)tissue-type plasminogen activator(t-PA), (3) plasminogen activator inhibitor(PAI) and (4) thromboxane B_2/6-keto-prostaglandin F_(1?)(TXB_2/6-k-PGF_(1?)). At the end of the experiment lung tissue was obtained for microscopic examination. Results The blood CEC count, PAI-1 level and TXB_2/6-k-PGF_(1?) ratio significantly increased while t-PA level significantly decreased at 4 h after burn in control group but at 4-28 h after burn in immersion group. The differences between the two groups were significant. Microscopic examination of the lung showed some thrombi in immersion group. Conclusion Burn causes acute damage to the endothelial cells of the whole body and disorder of hemostasis. They are more severe and last longer after seawater immersion.