Development of an experimental method for well-controlled blast induced traumatic limb fracture in rats

Heterotopic ossification(HO)is a consequence of traumatic bone and tissue damage,which occurs in 65%of military casualties with blast-associated amputations.However,the mechanisms behind blast-induced HO remain unclear.Animal models are used to study blast-induced HO,but developing such models is challenging,particularly in how to use a pure blast wave(primary blast)to induce limb fracture that then requires an amputation.Several studies,including our recent study,have developed platforms to induce limb fractures in rats with blast loading or a mixture of blast and impact loading.However,these models are limited by the survivability of the animal and repeatability of the model.In this study,we developed an improved platform,aiming to improve the animal's survivability and injury repeatability as well as focusing on primary blast only.The platform exposed only one limb of the rat to a blast wave while providing proper protection to the rest of the rat's body.We obtained very consistent fracture outcome in the tibia(location and pattern)in cadaveric rats with a large range of size and weight.Importantly,the rats did not obviously move during the test,where movement is a potential cause of uncontrolled injury.We further conducted parametric studies by varying the features of the design of the platform.These factors,such as how the limb is fixed and how the cavity through which the limb is placed is sealed,significantly affect the resulting injury.This platform and test setups enable well-controlled limb fracture induced directly by pure blast wave,which is the fundamental step towards a complete in vivo animal model for blast-induced HO induced by primary blast alone,excluding secondary and tertiary blast injury.In addition,the platform design and the findings presented here,particularly regarding the proper protection of the animal,have implications for future studies investigating localized blast injuries,such as blast induced brain and lung injuries.

Terrorist attacks:cutaneous patterns of gunshot and secondary blast injuries

Terrorist attacks have been on the rise.During the recent terrorist attacks in France,terrorists perpetrated their acts using weapons of war,as well as explosive charges.These two modes of action,when combined,can create skin lesions with similar macroscopic appearances,which can sometimes go unnoticed because of body fragmentation.A total of 68 autopsies,83 external examinations,140 standard radiographic examinations,and 49 computed tomography(CT)scans were performed over 7 days during the 2015 terrorist attacks in France.Bodies were injured by firearms and shrapnel-like projectiles.We analysed the clinical findings for the secondary blast cutaneous lesions from the explosive devices and compared these lesions with ballistic-related lesions to highlight that patterns can be macroscopically similar on external examination.Secondary blast injuries are characterised by penetrating trauma associated with materials added to explosive systems that are propelled by explosive air movement.These injuries are caused most often by small,shrapnel-like metallic objects,such as nails and bolts.Propulsion causes ballistic-type injuries that must be recognised and distinguished from those caused by firearm projectiles.Differentiating between these lesions is very difficult when using conventional criteria(size,shape,number and distribution on the body)with only external examination of corpses.This is why the particularities of these lesions must be further illustrated and then confirmed by complete autopsies and radiological and anatomopathological examinations.

Effect of minocycline and its nano-formulation on central auditory system in blast-induced hearing loss rat model

Blast injuries are common among the military service members and veterans.One of the devastating effects of blast wave induced TBI is either temporary or permanent hearing loss.Treating hearing loss using minocycline is restricted by optimal drug concentration,route of administration,and its half-life.Therefore,therapeutic approach using novel therapeutic delivery method is in great need.Among the different delivery methods,nanotechnology-based drug delivery is desirable,which can achieve longer systemic circulation,pass through some biological barriers and specifically targets desired sites.The current study aimed to examine therapeutic effect of minocycline and its nanoparticle formulation in moderate blast induced hearing loss rat model through central auditory system.The I.v.administered nanoparticle at reduced dose and frequency than regularly administered toxic dose.After moderate blast exposure,rats had hearing impairment as determined by ABR at 7-and 30-days post exposure.In chronic condition,free minocycline also showed the significant reduction in ABR threshold.In central auditory system,it is found in this study that minocycline nanoparticles ameliorate excitation in inferior colliculus;and astrocytes and microglia activation after the blast exposure is reduced by minocycline nanoparticles administration.The study demonstrated that in moderate blast induced hearing loss,minocycline and its nanoparticle formulation exhibited the optimal therapeutic effect on the recovery of the ABR impairment and a protective effect through central auditory system.In conclusion,targeted and non-targeted nanoparticle formulation have therapeutic effect on blast induced hearing loss.

Exposure to blast shock waves via the ear canal induces deficits in vestibular afferent function in rats

The ears are air-filled structures that are directly impacted during blast exposure.In addition to hearing loss and tinnitus,blast victims often complain of vertigo,dizziness and unsteady posture,suggesting that blast exposure induces damage to the vestibular end organs in the inner ear.However,the underlying mechanisms remain to be elucidated.In this report,single vestibular afferent activity and the vestibuloocular reflex(VOR)were investigated before and after exposure to blast shock waves(~20 PSI)delivered into the left external ear canals of anesthetized rats.Single vestibular afferent activity was recorded from the superior branch of the left vestibular nerves of the blast-treated and control rats one day after blast exposure.Blast exposure reduced the spontaneous discharge rates of the otolith and canal afferents.Blast exposure also reduced the sensitivity of irregular canal afferents to sinusoidal head rotation at 0.5e2Hz.Blast exposure,however,resulted in few changes in the VOR responses to sinusoidal head rotation and translation.To the best of our knowledge,this is the first study that reports blast exposure-induced damage to vestibular afferents in an animal model.These results provide insights that may be helpful in developing biomarkers for early diagnosis of blast-induced vestibular deficits in military and civilian populations.

Biomechanical modeling for the response of human thorax to blast waves

A simplified finite element model of a human thorax had been developed for probing into the mechani- cal response in simple and complex blast environments. The human thorax model was first created by CT images with blast loading applied via a coupled arbitrary Lagrangian- Eulerian method, allowing for a variety of loads to be considered. The goal is to analyze the maximum stress distri- butions of lung tissue and peak inward thorax wall velocity and to know the possible regions and levels of lung injury. In parallel, a mathematical model has been modified from the Lobdell model to investigate the detailed percentage of lung injury at each level. The blast loadings around the human tho- rax were obtained from the finite element model, and were then applied in the mathematical model as the boundary con- ditions to predict the normalized work of the human thorax lung. The present results are found in agreement with the modified Bowen curves and the results predicted by Axels- son＇s model.

Three Reverse Adipofascial Cross Finger Flaps Used for Coverage of Raw Areas on Two Fingers of a Patient with Blast Injury of the Hand—Case Report

We report a case of blast injury to the left hand which resulted in fractures of the fingers with exposure of bones and joints of the phalanges. We used three reverse adipofascial cross finger flaps raised at the same time from 2 fingers to reconstruct adjacent fingers of the patient. The patient recovered well postoperatively and had good range of movement of the fingers. This avoided the complications of the use of regional or distal flaps. To our knowledge, this is the first case reported in which three reverse adipofascial cross fingers flaps are raised at the same time, two of them from an injured finger, to cover three raw areas on two fingers of a patient.

Identification of overlay differentially expressed genes in both rats and goats with blast lung injury through comparative transcriptomics

Purpose:To identify the potential target genes of blast lung injury(BLI)for the diagnosis and treatment.Methods:This is an experimental study.The BLI models in rats and goats were established by conducting a fuel-air explosive power test in an unobstructed environment,which was subsequently validated through hematoxylin-eosin staining.Transcriptome sequencing was performed on lung tissues from both goats and rats.Differentially expressed genes were identified using the criteria ofq≤0.05 and|log2 fold change|≥1.Following that,enrichment analyses were conducted for gene ontology and the Kyoto Encyclopedia of Genes and Genomes pathways.The potential target genes were further confirmed through quantitative real-time polymerase chain reaction and enzyme linked immunosorbent assay.Results:Observations through microscopy unveiled the presence of reddish edema fluid,erythrocytes,and instances of focal or patchy bleeding within the alveolar cavity.Transcriptome sequencing analysis identified a total of 83 differentially expressed genes in both rats and goats.Notably,49 genes exhibited a consistent expression pattern,with 38 genes displaying up-regulation and 11 genes demonstrating down-regulation.Enrichment analysis highlighted the potential involvement of the interleukin-17 signaling pathway and vascular smooth muscle contraction pathway in the underlying mechanism of BLI.Furthermore,the experimental findings in both goats and rats demonstrated a strong association between BLI and several key genes,including anterior gradient 2,ankyrin repeat domain 65,bactericidal/permeability-increasing fold containing family A member 1,bactericidal/permeability-increasing fold containing family B member 1,and keratin 4,which exhibited up-regulation.Conclusions:Anterior gradient 2,ankyrin repeat domain 65,bactericidal/permeability-increasing fold containing family A member 1,bactericidal/permeability-increasing fold containing family B member 1,and keratin 4 hold potential as target genes for the prognosis,diagnosis,and treatment of BLI.

Bombings specific triage(Bost Tool) tool and its application by healthcare professionals

BACKGROUND: Bombing is a unique incident which produces unique patterns, multiple and occult injuries. Death often is a result of combined blast, ballistic and thermal effect injuries. Various natures of injury, self referrals and arrival by private transportation may lead to "wrong triage" in the emergency department. In India there has been an increase in incidence of bombing in the last 15 years. There is no documented triage tool from the National Disaster Management Authority of India for Bombings. We have tried to develop an ideal bombing specific triage tool which will guide the right patients to the right place at the right time and save more lives.METHODS: There are three methods of studying the triage tool: 1) real disaster; 2) mock drill; 3) table top exercise. In this study, a table top exercise method was selected. There are two groups, each consisting of an emergency physician, a nurse and a paramedic.RESULTS: By using the proportion test, we found that correct triaging was significantly different(P=0.005) in proportion between the two groups: group B(80%) with triage tool performed better in triaging the bomb blast victims than group A(50%) without the bombing specific triage tool performed.CONCLUSION: Development of bombing specific triage tool can reduce under triaging.

Effects of orientation and distance of goats on blast lung injury characteristics on a plateau above 4500-meter

Purpose:High explosives are used to produce blast waves to study their biological effects.The lungs are considered as the critical target organ in blast-effect studies.The degree of lung hemorrhaging is related to both the explosive power and the increased lung weight.We studied the characteristics of the biological effects from an air explosion of a thermobaric bomb in a high-altitude environment and the lethality and lung injury severity of goats in different orientations and distances.Methods:Goats were placed at 2.5,3,4,and 5 m from the explosion center and exposed them to an air blast at an altitude of 4700-meter.A group of them standing oriented to the right side and the other group seated facing the explosion center vertically.The lung injuries were quantified according to the percentage of surface area contused,and using the pathologic severity scale of lung blast injury(PSSLBI)to score the 4 injury categories(slight,moderate,serious and severe)as 1,2,3,and 4,respectively.The lung coefficient(lung weight[g]/body weight[kg])was the indicator of pulmonary edema and was related to lung injury severity.Blast overpressure data were collected using blast test devices placed at matching locations to represent loadings to goats.All statistical analyses were performed using SPSS,version 26.0,statistical software(SPSS,Inc.,Chicago,IL,USA).Results:In total,127 goats were involved in this study.Right-side-standing goats had a significantly higher mortality rate than those seated vertical-facing(p<0.05).At the 2.5 m distance,the goat mortality was nearly 100%,whereas at 5 m,all the goats survived.Lung injuries of the right-side-standing goats were 1-2 grades more serious than those of seated goats at the same distances,the scores of PSSLBI were significantly higher than the seated vertical-facing goats(p<0.05).The lung coefficient of the right-side-standing goats were significantly higher than those of seated vertical-facing(p<0.05).Mortality,PSSLBI,and the lung coefficient results indicated that the right-side-standing goats experienced severer injuries than the seated vertical-facing goats,and the injuries were lessened as the distance increased.The blast overpressure was consistent with these results.Conclusion:The main killing factors of the thermobaric bomb in the high-altitude environment were blast overpressure,blast wind propulsions and burn.The orientation and distances of the goats significantly affected the blast injury severity.These results may provide a research basis for diagnosing,treating and protecting against injuries from thermobaric explosions.

It's all about timing, early treatment with hyperbaric oxygen therapy and corticosteroids is essential in acute acoustic trauma

Background: Acute acoustic trauma (AAT) is an acute hearing impairment caused by intense noiseimpact. The current management strategy for AAT with substantial hearing loss in the Dutch militaryis the combination therapy with corticosteroids and hyperbaric oxygen therapy (HBOT). In a previousstudy, early initiation of the combination therapy was associated with better outcomes. Therefore, weperformed a new analysis to assess the difference in hearing outcome between patients in whomcombination therapy was started within two days, versus after more than two days.Methods: A retrospective analysis was performed on military patients diagnosed with AAT with substantial hearing loss who presented between February 2018 and March 2020. Absolute and relativehearing improvement between first and last audiograms were calculated for all affected frequencies(defined as loss of 20 dB on initial audiogram). We also determined the amount of patients whorecovered to the level of Dutch military requirement, and performed speech discrimination tests.Results: In this analysis, 30 male patients (49 ears) with AAT were included. The median age was 24.5years (IQR 23e29). The median time to initiation of therapy with corticosteroids and HBOT were one andtwo days, respectively. HBOT was started within two days in 31 ears, and after more than two days in 18ears. The mean absolute and relative hearing gains were 18.8 dB (SD 14.6) and 46.8% (SD 31.3) on allaffected frequencies. The 100% discrimination/speech perception level improved from 64.0 dB to 51.7 dB(gain 12.3 dB ± 14.1). There was significantly more improvement in absolute and relative hearingimprovement when HBOT was started in 2 days, compared to >2 days.Conclusion: Our analysis shows results in favor of early initiation ( 2 days) of the combination treatmentof HBOT and corticosteroids in patients with AAT.

Blast Injury from Locally Manufactured“Hakka Patas”

Explosives are potentially harmful devices that can create an explosion by a rapid release of a pressurized gas consequent to a chemical reaction within the device.They can inflict a variety of injuries,due to the blast wave,fire,and shrapnel.The pattern and severity of injuries will be determined by various factors,including explosive potential and constituents such as shrapnel.Homemade explosive devices(HEDs)pose a further threat due to their volatile,unpredictable nature which can lead to accidental explosions.We present the case of a 28-year-old farmer who presented with extensive blast injury to the left hand from a“Hakka patas,”a HED endemic to Sri Lanka.The injuries to his hand consisted of extensive soft tissue and muscle loss,and fractures of metacarpal bones with amputation of the first distal phalanx.Low-grade explosives such as“Hakka patas”have the potential to cause injury greater than expected due to their volatile,unpredictable nature,causing accidental explosions.This can injure unintended targets,resulting in grave consequences.The specific pattern described in low-grade explosive injuries will be important to differentiate other explosive-related injuries for medicolegal purposes.

Global gene expression profiling of blast lung injury of goats exposed to shock wave

Purpose:Blast lung injury(BLI)is the most common damage resulted from explosion-derived shock wave in military,terrorism and industrial accidents.However,the molecular mechanisms underlying BLI induced by shock wave are still unclear.Methods:In this study,a goat BLI model was established by a fuel air explosive power.The key genes involved in were identified.The goats of the experimental group were fixed on the edge of the explosion cloud,while the goats of the control group were 3 km far away from the explosive environment.After successful modeling for 24 h,all the goats were sacrificed and the lung tissue was harvested for histopathological observation and RNA sequencing.Gene ontology(GO)and kyoto encyclopedia of genes and genomes(KEGG)analysis were performed to identify the main enriched biological functions of differentially expressed genes(DEGs).Quantitative real-time polymerase chain reaction(qRT-PCR)was used to verify the consistency of gene expression.Results:Of the sampled goat lungs,895 genes were identified to be significantly differentially expressed,and they were involved in 52 significantly enriched GO categories.KEGG analysis revealed that DEGs were highly enriched in 26 pathways,such as cytokine-cytokine receptor interaction,antifolate resistance,arachidonic acid metabolism,amoebiasis and bile secretion,JAK-STAT,and IL-17 signaling pathway.Furthermore,15 key DEGs involved in the biological processes of BLI were confirmed by qRTPCR,and the results were consistent with RNA sequencing.Conclusion:Gene expression profiling provide a better understanding of the molecular mechanisms of BLI,which will help to set strategy for treating lung injury and preventing secondary lung injury induced by shock wave.

Plastic surgeons: critical members of the mass casualty team

Plastic and reconstructive surgeons are uniquely positioned to care for a variety of patients in all walks of life.We routinely take part in the multidisciplinary care that ranges from prenatal consultation for congenital abnormalities such as cleft lip and palate to nuanced reconstructive care of our aging population after tumor extirpation.

Belgium experience in disaster victim identification applied in handling terrorist attack at Brussels Airport 2016

The Belgian disaster victim identification(DVI)team is involved in many investigations in our country.Indeed,this specialized team of the federal police oversees searching for and investigating criminally buried dead bodies,identification of unknown putrefied corpses,and more.The Belgian DVI team also assists with the identification of victims of mass disasters(natural,accidental,and mass murders).In this article,we consider the contributions of different teams(forensic pathology,anthropology,and odontology,federal police,and crime scene investigation)both on the scene of the attack at the Brussels National Airport(Zaventem)and in the laboratory work(autopsies,sample studies).