Hippocampal Expression of Cytochrome P450 1B1 in Penetrating Traumatic Brain Injury.

Hippocampal dysfunction contributes to multiple traumatic brain injury sequala. Female rodents' outcome is superior to male which has been ascribed the neuroprotective sex hormones 17ß-estradiol and progesterone. Cytochrome P450 1B1 (CYP1B1) is an oxidative enzyme influencing the neuroinflammatory response by creating inflammatory mediators and metabolizing neuroprotective 17ß-estradiol and progesterone. In this study, we aimed to describe hippocampal CYP1B1 mRNA expression, protein presence of CYP1B1 and its key redox partner Cytochrome P450 reductase (CPR) in both sexes, as well as the effect of penetrating traumatic brain injury (pTBI). A total 64 adult Sprague Dawley rats divided by sex received pTBI or sham-surgery and were assigned survival times of 1-, 3-, 5- or 7 days. CYP1B1 mRNA was quantified using in-situ hybridization and immunohistochemistry performed to verify protein colocalization. CYP1B1 mRNA expression was present in all subregions but greatest in CA2 irrespective of sex, survival time or intervention. At 3-, 5- and 7 days post-injury, expression in CA2 was reduced in male rats subjected to pTBI compared to sham-surgery. Females subjected to pTBI instead exhibited increased expression in all CA subregions 3 days post-injury, the only time point expression in CA2 was greater in females than in males. Immunohistochemical analysis confirmed neuronal CYP1B1 protein in all hippocampal subregions, while CPR was limited to CA1 and CA2. CYP1B1 mRNA is constitutively expressed in both sexes. In response to pTBI, females displayed a more urgent but brief regulatory response than males. This indicates there may be sex-dependent differences in CYP1B1 activity, possibly influencing inflammation and neuroprotection in pTBI.

COX-2 regulation and TUNEL-positive cell death differ between genders in the secondary inflammatory response following experimental penetrating focal brain injury in rats.

INTRODUCTION: Traumatic brain injury is followed by secondary neuronal degeneration, largely dependent on an inflammatory response. This response is probably gender specific, since females are better protected than males in experimental models. The reasons are not fully known. We examined aspects of the inflammatory response following experimental TBI in male and female rats to explore possible gender differences at 24 h and 72 h after trauma, times of peak histological inflammation and neuronal degeneration. METHODS: A penetrating brain injury model was used to produce penetrating focal TBI in 20 Sprague-Dawley rats, 5 males and 5 females for each time point. After 24 and 72 h the brains were removed and subjected to in situ hybridization and immunohistochemical analyses for COX-2, iNOS, osteopontin, glial fibrillary acidic protein, 3-nitrotyrosine, TUNEL and Fluoro-Jade. RESULTS: COX-2 mRNA and protein levels were increased in the perilesional area compared to the uninjured contralateral side and significantly higher in males at 24 h and 72 h (p < 0.05). iNOS mRNA was significantly increased in females at 24 h (p < 0.05) although protein was not. TUNEL was increased in male rats after 24 h (p < 0.05). Glial fibrillary acidic protein, osteopontin, 3-nitrotyrosine and Fluoro-Jade stained degenerating neurons were increased in the perilesional area, showing no difference between genders. CONCLUSIONS: COX-2 regulation differed between genders after TBI. The increased COX-2 expression in male rats correlated with increased apoptotic cell death detected by increased TUNEL staining at 24 h, but not with neuronal necrosis measured by Flouro-Jade. Astrogliosis and microgliosis did not differ, confirming a comparable level of trauma. The gender-specific trait of the secondary inflammatory response may be connected to prostaglandin regulation, which may partially explain gender variances in outcome after TBI.

Simulating Pelvis Kinematics from Belt and Seat Loading in Frontal Car Crash Scenarios: Important Boundary Conditions that Influence the Outcome.

PURPOSE: The risk of submarining during automotive crashes, defined by the lap belt sliding off the pelvis to load the abdomen, is predicted to increase in future autonomous vehicles as greater variation in seating position is enabled. Biofidelic tools are required to efficiently design and evaluate new and/or improved safety systems. This study aims to evaluate the pelvis response sensitivity to variations in boundary conditions that directly influence the pelvis loads, deemed important for the submarining outcome, to facilitate a more precise comparison between finite element human body models (FE-HBMs) and post-mortem human subjects (PMHSs). METHODS: A parameter study, using a one-variable-at-a-time analysis (low/high) of belt friction, seat friction, seat stiffness, and (on/off) for added belt bending stiffness, was performed using a state-of-the-art FE-HBM in four different test scenarios; one stationary, two sleds with upright occupant posture, and one sled with reclined occupant posture. RESULTS: In the stationary scenario, both belt friction and belt bending stiffness influenced the belt folding behavior, which consequently affected the belt-to-pelvis angle at submarining. In the sled scenarios, only seat friction was found to influence the pelvis kinematics and submarining outcome, with the most biofidelic response resulting from both the low (0.2) and high (0.5) friction coefficient depending on the scenario. CONCLUSION: To reduce uncertainty in boundary conditions affecting the external pelvis loads and increase confidence in FE-HBM to PMHS comparisons, it is recommended that future experiments evaluate the PMHS to seat friction coefficient and that new belt modeling methods that accurately capture belt folding when interacting with soft tissues are developed.

Investigating sources for variability in volunteer kinematics in a braking maneuver, a sensitivity analysis with an active human body model.

Occupant kinematics during evasive maneuvers, such as crash avoidance braking or steering, varies within the population. Studies have tried to correlate the response to occupant characteristics such as sex, stature, age, and BMI, but these characteristics explain no or very little of the variation. Therefore, hypothesis have been made that the difference in occupant response stems from voluntary behavior. The aim of this study was to investigate the effect from other sources of variability: in neural delay, in passive stiffness of fat, muscle tissues and skin, in muscle size and in spinal alignment, as a first step towards explaining the variability seen among occupants in evasive maneuvers. A sensitivity analysis with simulations of the SAFER Human Body Model in braking was performed, and the displacements from the simulations were compared to those of volunteers. The results suggest that the head and torso kinematics were most sensitive to spinal alignment, followed by muscle size. For head and torso vertical displacements, the range in model kinematics was comparable to the range in volunteer kinematics. However, for forward displacements, the included parameters only explain some of the variability seen in the volunteer experiment. To conclude, the results indicate that the variation in volunteer vertical kinematics could be partly attributed to the variability in human characteristics analyzed in this study, while these cannot alone explain the variability in forward kinematics. The results can be used in future tuning of HBMs, and in future volunteer studies, when further investigating the potential causes of the large variability seen in occupant kinematics in evasive maneuvers.

Predicting occupant head displacements in evasive maneuvers; tuning and comparison of a rotational based and a translational based neck muscle controller.

Objective: Real-life car crashes are often preceded by an evasive maneuver, which can alter the occupant posture and muscle state. To simulate the occupant response in such maneuvers, human body models (HBMs) with active muscles have been developed. The aim of this study was to implement an omni-directional rotational head-neck muscle controller in the SAFER HBM and compare the bio-fidelity of the HBM with a rotational controller to the HBM with a translational controller, in simulations of evasive maneuvers. Methods: The rotational controller was developed using an axis-angle representation of head rotations, with x, y, and z components in the axis. Muscle load sharing was based on rotational direction in the simulation and muscle activity recorded in three volunteer experiments in these directions. The gains of the rotational and translational controller were tuned to minimize differences between translational and rotational head displacements of the HBM and volunteers in braking and lane change maneuvers using multi-objective optimizations. Bio-fidelity of the model with tuned controllers was evaluated objectively using CORrelation and Analysis (CORA). Results: The results indicated comparable performance for both controllers after tuning, with somewhat higher bio-fidelity for rotational kinematics with the translational controller. After tuning, good or excellent bio-fidelity was indicated for both controllers in the loading direction (forward in braking, and lateral in lane change), with CORA scores of 0.86-0.99 and 0.93-0.98 for the rotational and translational controllers, respectively. For rotational displacements, and translational displacements in the other directions, bio-fidelity ranged from poor to excellent, with slightly higher average CORA scores for the HBM with the translational controller in both braking and lane changing. Time-averaged muscle activity was within one standard deviation of time-averaged muscle activity from volunteers. Conclusion: Overall, the results show that when tuned, both the translational and rotational controllers can be used to predict the occupant response to an evasive maneuver, allowing for the inclusion of evasive maneuvers prior to a crash in evaluation of vehicle safety. The rotational controller shows potential in controlling omni-directional head displacements, but the translational controller outperformed the rotational controller. Thus, for now, the recommendation is to use the translational controller with tuned gains.

Assessment of fluorescent protein candidates for multi-color flow cytometry analysis of Saccharomyces cerevisiae.

Transcription factor-based biosensors represent promising tools in the construction and evaluation of efficient cell factories for the sustainable production of fuels, chemicals and pharmaceuticals. They can notably be designed to follow the production of a target compound or to monitor key cellular properties, such as stress or starvation. In most cases, the biosensors are built with fluorescent protein (FP) genes as reporter genes because of the direct correlation between promoter activity and fluorescence level that can be measured using, for instance, flow cytometry or fluorometry. The expansion of available FPs offers the possibility of using several FPs - and biosensors - in parallel in one host, with simultaneous detection using multicolor flow cytometry. However, the technique is currently limited by the unavailability of combinations of FP whose genes can be successfully expressed in the host and whose fluorescence can be efficiently distinguished from each other. In the present study, the broad collection of available FPs was explored and four different FPs were successfully expressed in the yeast Saccharomyces cerevisiae: yEGFP, mEGFP, CyOFP1opt and mBeRFPopt. After studying their fluorescence signals, population heterogeneity and possible interactions, we recommend two original combinations of FPs for bi-color flow cytometry: mEGFP together with either CyOFP1opt or mBeRFPopt, as well as the combination of all three FPs mEGFP, CyOFP1opt and mBeRFPopt for tri-color flow cytometry. These combinations will allow to perform different types of bi-color or possibly tri-color flow cytometry and FACS experiments with yeast, such as phenotype evaluation, screening or sorting, by single-laser excitation with a standard 488 nm blue laser.

Identifying individual-based injury patterns in multi-trauma road users by using an association rule mining method.

In many road crashes the human body is exposed to high forces, commonly resulting in multiple injuries. This study of linked road crash data aimed to identify co-occurring injuries in multiple injured road users by using a novel application of a data mining technique commonly used in Market Basket Analysis. We expected that some injuries are statistically associated with each other and form Individual-Based Injury Patterns (IBIPs) and further that specific road users are associated with certain IBIPs. First, a new injury taxonomy was developed through a four-step process to allow the use of injury data recorded from either of the two major dictionaries used to document anatomical injury. Then data from the Swedish Traffic Accident Data Acquisition, which includes crash circumstances from the police and injury information from hospitals, was analysed for the years 2011 to 2017. The injury data was analysed using the Apriori algorithm to identify statistical association between injuries (IBIP). Each IBIP were then used as the outcome variable in logistic regression modelling to identify associations between specific road user types and IBIPs. A total of 48,544 individuals were included in the analysis of which 36,480 (75.1%) had a single injury category recorded and 12,064 (24.9%) were considered multiply injured. The data mining analysis identified 77 IBIPs in the multiply injured sample and 16 of these were associated with only one road user type. IBIPs and their relation to road user type are one step on the journey towards developing a tool to better understand and quantify injury severity and thereby improve the evidence-base supporting prioritisation of road safety countermeasures.

Female kinematics and muscle responses in lane change and lane change with braking maneuvers.

OBJECTIVE: The primary aim of this article is to extensively study female occupant kinematics and muscle activations in vehicle maneuvers potentially occurring in precrash situations and with different seat belt configurations. The secondary aim is to provide validation data for active human body models (AHBMs) of female occupants in representative precrash loading situations. METHODS: Front seat female passengers wearing a 3-point seat belt, with either standard or pre-pretensioning functionality, were subjected to multiple autonomously carried-out lane change and lane change with braking maneuvers while traveling at 73 km/h. This article quantifies the head center of gravity and T1 vertebra body (T1) linear and rotational displacements. This article also includes surface electromyography (EMG) data collected from 38 muscles in the neck, torso, and upper and lower extremities, all normalized by maximum voluntary contraction (MVC). The raw EMG data were filtered, rectified, and smoothed. Separate Wilcoxon signed-rank tests were performed on EMG onset and amplitude as well as peak displacements of head and T1 considering 2 paired samples with the belt configuration as an independent variable. RESULTS: Significantly smaller lateral and forward displacements for head and T1 were found with the pre-pretensioner belt versus the standard belt (P < .05). Averaged muscle activity, mainly in the neck, lumbar extensor, and abdominal muscles, increased up to 16% MVC immediately after the vehicle accelerated in the lateral direction. Muscles in the right and left sides of the body displayed differences in activation time and amplitude relative to the vehicle's lateral motion. For specific muscles, lane changes with the pre-pretensioner belt resulted in earlier muscle activation onsets and significantly smaller activation amplitudes compared to the standard belt (P < .05). CONCLUSIONS: The presented results from female passengers complement the previously published results from male passengers subjected to the same loading scenarios. The data provided in this article can be used for validation of AHBMs of female occupants in both sagittal and lateral loading scenarios potentially occurring prior to a crash. Additionally, our results show that a pre-pretensioner belt decreases muscle activation onset and amplitude as well as forward and lateral displacements of head and T1 compared to a standard belt, confirming previously published results.

The influence of car passengers' sitting postures in intersection crashes.

Car passengers are frequently sitting in non-nominal postures and are able to perform a wide range of activities since they are not limited by tasks related to vehicle control, contrary to drivers. The anticipated introduction of Autonomous Driven vehicles could allow "drivers" to adopt similar postures and being involved in the same activities as passengers, allowing them a similar set of non-nominal postures. Therefore, the need to investigate the effects of non-nominal occupant sitting postures during relevant car crash events is becoming increasingly important. This study aims to investigate the effect of different postures of passengers in the front seat of a car on kinematic and kinetic responses during intersection crashes. A Human Body Model (HBM) was positioned in a numerical model of the front passenger seat of a midsize Sports Utility Vehicle (SUV) in a total of 35 postures, including variations to the lower and upper extremities, torso, and head postures. Three crash configurations, representative of predicted urban intersection crashes, were assessed in a simulation study; two side impacts, a near-side and a far-side, respectively, and a frontal impact. The occupant kinematics and internal loads were analyzed, and any deviation between the nominal and altered posture responses were quantified using cross-correlation of signals to highlight the most notable variations. Posture changes to the lower extremities had the largest overall influence on the lower extremities, pelvis, and whole-body responses for all crash configurations. In the frontal impact, crossing the legs allowed for the highest pelvis excursions and rotations, which affected the whole-body response the most. In the two side-impacts, leaning the torso in the coronal plane affected the torso and head kinematics by changing the interaction with the vehicle's interior. Additionally, in far-side impacts supporting the upper extremity on the center console resulted in increased torso excursions. Moreover, the response of the upper extremities was consistently sensitive to posture variations of all body regions.

Dynamic Spatial Tuning Patterns of Shoulder Muscles with Volunteers in a Driving Posture.

Computational human body models (HBMs) of drivers for pre-crash simulations need active shoulder muscle control, and volunteer data are lacking. The goal of this paper was to build shoulder muscle dynamic spatial tuning patterns, with a secondary focus to present shoulder kinematic evaluation data. 8M and 9F volunteers sat in a driver posture, with their torso restrained, and were exposed to upper arm dynamic perturbations in eight directions perpendicular to the humerus. A dropping 8-kg weight connected to the elbow through pulleys applied the loads; the exact timing and direction were unknown. Activity in 11 shoulder muscles was measured using surface electrodes, and upper arm kinematics were measured with three cameras. We found directionally specific muscle activity and presented dynamic spatial tuning patterns for each muscle separated by sex. The preferred directions, i.e. the vector mean of a spatial tuning pattern, were similar between males and females, with the largest difference of 31° in the pectoralis major muscle. Males and females had similar elbow displacements. The maxima of elbow displacements in the loading plane for males was 189 ± 36 mm during flexion loading, and for females, it was 196 ± 36 mm during adduction loading. The data presented here can be used to design shoulder muscle controllers for HBMs and evaluate the performance of shoulder models.

Design and Evaluation of the Initial 50th Percentile Female Prototype Rear Impact Dummy, BioRID P50F - Indications for the Need of an Additional Dummy Size.

The objective of this study was to present the design of a prototype rear impact crash test dummy, representing a 50th percentile female, and compare its performance to volunteer response data. The intention was to develop a first crude prototype as a first step toward a future biofidelic 50th percentile female rear impact dummy. The current rear impact crash test dummy, BioRID II, represents a 50th percentile male, which may limit the assessment and development of whiplash protection systems with regard to female occupants. Introduction of this new dummy size will facilitate evaluation of seat and head restraint (HR) responses in both the average sized female and male in rear impacts. A 50th percentile female rear impact prototype dummy, the BioRID P50F, was developed from modified body segments originating from the BioRID II. The mass and rough dimensions of the BioRID P50F is representative of a 50th percentile female. The prototype dummy was evaluated against low severity rear impact sled tests comprising six female volunteers closely resembling a 50th percentile female with regard to stature and mass. The head/neck response of the BioRID P50F prototype resembled the female volunteer response corridors. The stiffness of the thoracic and lumbar spinal joints remained the same as the average sized male BioRID II, and therefore likely stiffer than joints of an average female. Consequently, the peak rearward angular displacement of the head and T1, and the rearward displacement of the T1, were lesser for the BioRID P50F in comparison to the female volunteers. The biofidelity of the BioRID P50F prototype thus has some limitations. Based on a seat response comparison between the BioRID P50F and the BioRID II, it can be concluded that the male BioRID II is an insufficient representation of the average female in the assessment of the dynamic seat response and effectiveness of whiplash protection systems.

Predicting pelvis geometry using a morphometric model with overall anthropometric variables.

Pelvic fractures have been identified as the second most common AIS2+ injury in motor vehicle crashes, with the highest early mortality rate compared to other orthopaedic injuries. Further, the risk is associated with occupant sex, age, stature and body mass index (BMI). In this study, clinical pelvic CT scans from 132 adults (75 females, 57 males) were extracted from a patient database. The population shape variance in pelvis bone geometry was studied by Sparse Principal Component Analysis (SPCA) and a morphometric model was developed by multivariate linear regression using overall anthropometric variables (sex, age, stature, BMI). In the analysis, SPCA identified 15 principal components (PCs) describing 83.6% of the shape variations. Eight of these were significantly captured (α < 0.05) by the morphometric model, which predicted 29% of the total variance in pelvis geometry. The overall anthropometric variables were significantly related to geometrical features primarily in the inferior-anterior regions while being unable to significantly capture local sacrum features, shape and position of ASIS and lateral tilt of the iliac wings. In conclusion, a new detailed morphometric model of the pelvis bone demonstrated that overall anthropometric variables account for only 29% of the variance in pelvis geometry. Furthermore, variations in the superior-anterior region of the pelvis, with which the lap belt is intended to interact, were not captured. Depending on the scenario, shape variations not captured by overall anthropometry could have important implications for injury prediction in traffic safety analysis.

Defining crash configurations for Powered Two-Wheelers: Comparing ISO 13232 to recent in-depth crash data from Germany, India and China.

The motorcyclist safety standard ISO 13232, based on crash data from Europe and the USA from the 1970s, still sets the direction for the development and evaluation of protective measures today. However, it is unclear how relevant the crash configurations in the standard are to present-day motorcycle crashes in Europe, the USA and other parts of the world. We analyzed recent in-depth crash data from Germany, India and China, examining powered two-wheeler (PTW) crash configurations in which at least one police-reported serious injury was present. After assessing the relevance of the ISO's PTW crash configurations to those we found in each country, we suggested new configurations to guide the development of safety systems that would be more effective at reducing PTW-related fatalities and serious injuries. In all three databases, passenger cars were among the top two most frequent collision partners and a car front impacting the side of the PTW was the most common configuration. Notably, although collisions with trucks constituted the most common scenario in India and ground impact (primary collision) was a common scenario in both Germany and India, the ISO did not include either configuration. Further, in three of the seven ISO crash configurations, one of the collision partners is stationary, although stationary collision partners were rare in our data. Our results show that the ISO crash configurations do not represent the most frequent PTW road crashes in Germany, India or China. However, the Chinese database was confined to crashes with a collision partner with four or more wheels. Further, weighting factors for these data were not available, so we could not extrapolate the frequency of the Chinese crash configurations across the entire population. A revised version of the ISO could serve as a basis for a full-scale PTW crash test program. However, the observed differences between countries imply that a single global standard may not be feasible. To optimize the evaluation of a PTW safety system, we recommend the inclusion of configurations which are frequent in the region or country of interest-in addition to common configurations occurring frequently all around the world.

Dynamic Responses of Female Volunteers in Rear Impact Sled Tests at Two Head Restraint Distances.

The objective of this study was to assess the biomechanical and kinematic responses of female volunteers with two different head restraint (HR) configurations when exposed to a low-speed rear loading environment. A series of rear impact sled tests comprising eight belted, near 50th percentile female volunteers, seated on a simplified laboratory seat, was performed with a mean sled acceleration of 2.1 g and a velocity change of 6.8 km/h. Each volunteer underwent two tests; the first test configuration, HR10, was performed at the initial HR distance ∼10 cm and the second test configuration, HR15, was performed at ∼15 cm. Time histories, peak values and their timing were derived from accelerometer data and video analysis, and response corridors were also generated. The results were separated into three different categories, HR10 C (N = 8), HR15 C (N = 6), and HR15 N C (N = 2), based on: (1) the targeted initial HR distance [10 cm or 15 cm] and (2) whether the volunteers' head had made contact with the HR [Contact (C) or No Contact (NC)] during the test event. The results in the three categories deviated significantly. The greatest differences were found for the average peak head angular displacements, ranging from 10° to 64°. Furthermore, the average neck injury criteria (NIC) value was 22% lower in HR10 C (3.9 m2/s2), and 49% greater in HR15 N C (7.4 m2/s2) in comparison to HR15 C (5.0 m2/s2). This study supplies new data suitable for validation of mechanical or mathematical models of a 50th percentile female. A model of a 50th percentile female remains to be developed and is urgently required to complement the average male models to enhance equality in safety assessments. Hence, it is important that future protection systems are developed and evaluated with female properties taken into consideration too. It is likely that the HR15 test configuration is close to the limit for avoiding HR contact for this specific seat setup. Using both datasets (HR15 C and HR15 N C ), each with its corresponding HR contact condition, will be possible in future dummy or model evaluation.

A method for predicting crash configurations using counterfactual simulations and real-world data.

Traffic safety technologies revolve around two principle ideas; crash avoidance and injury mitigation for inevitable crashes. The development of relevant vehicle injury mitigating technologies should consider the interaction of those two technologies, ensuring that the inevitable crashes can be adequately managed by the occupant and vulnerable road user (VRU) protection systems. A step towards that is the accurate description of the expected crashes remaining when crash-avoiding technologies are available in vehicles. With the overall objective of facilitating the assessment of future traffic safety, this study develops a method for predicting crash configurations when introducing crash-avoiding countermeasures. The predicted crash configurations are one important factor for prioritizing the evaluation and development of future occupant and VRU protection systems. By using real-world traffic accident data to form the baseline and performing counterfactual model-in-the-loop (MIL) pre-crash simulations, the change in traffic situations (vehicle crashes) provided by vehicles with crash-avoiding technologies can be predicted. The method is built on a novel crash configuration definition, which supports further analysis of the in-crash phase. By clustering and grouping the remaining crashes, a limited number of crash configurations can be identified, still representing and covering the real-world variation. The developed method was applied using Swedish national- and in-depth accident data related to urban intersections and highway driving, and a conceptual Autonomous Emergency Braking system (AEB) computational model. Based on national crash data analysis, the conflict situations Same-Direction rear-end frontal (SD-ref) representing 53 % of highway vehicle-to-vehicle (v2v) crashes, and Straight Crossing Path (SCP) with 21 % of urban v2v intersection crashes were selected for this study. Pre-crash baselines, for SD-ref (n = 1010) and SCP (n = 4814), were prepared based on in-depth accident data and variations of these. Pre-crash simulations identified the crashes not avoided by the conceptual AEB, and the clustering of these revealed 5 and 52 representative crash configurations for the highway SD-ref and urban intersection SCP conflict situations, respectively, to be used in future crashworthiness studies. The results demonstrated a feasible way of identifying, in a predictive way, relevant crash configurations for in-crash testing of injury prevention capabilities.

Diffuse Axonal Injury in the Rat Brain: Axonal Injury and Oligodendrocyte Activity Following Rotational Injury.

Traumatic brain injury (TBI) commonly results in primary diffuse axonal injury (DAI) and associated secondary injuries that evolve through a cascade of pathological mechanisms. We aim at assessing how myelin and oligodendrocytes react to head angular-acceleration-induced TBI in a previously described model. This model induces axonal injuries visible by amyloid precursor protein (APP) expression, predominantly in the corpus callosum and its borders. Brain tissue from a total of 27 adult rats was collected at 24 h, 72 h and 7 d post-injury. Coronal sections were prepared for immunohistochemistry and RNAscope® to investigate DAI and myelin changes (APP, MBP, Rip), oligodendrocyte lineage cell loss (Olig2), oligodendrocyte progenitor cells (OPCs) (NG2, PDGFRa) and neuronal stress (HSP70, ATF3). Oligodendrocytes and OPCs numbers (expressed as percentage of positive cells out of total number of cells) were measured in areas with high APP expression. Results showed non-statistically significant trends with a decrease in oligodendrocyte lineage cells and an increase in OPCs. Levels of myelination were mostly unaltered, although Rip expression differed significantly between sham and injured animals in the frontal brain. Neuronal stress markers were induced at the dorsal cortex and habenular nuclei. We conclude that rotational injury induces DAI and neuronal stress in specific areas. We noticed indications of oligodendrocyte death and regeneration without statistically significant changes at the timepoints measured, despite indications of axonal injuries and neuronal stress. This might suggest that oligodendrocytes are robust enough to withstand this kind of trauma, knowledge important for the understanding of thresholds for cell injury and post-traumatic recovery potential.

Evaluation of injury thresholds for predicting severe head injuries in vulnerable road users resulting from ground impact via detailed accident reconstructions.

The aim of this study was to evaluate the effectiveness of various head injury criteria and associated risk functions in prediction of vulnerable road users (VRUs) severe head injuries caused by ground impact during vehicle collisions. Ten VRU accidents with video information were reconstructed by using Chalmers Pedestrian Model, vehicle multi-body system models and the THUMS (Ver. 4.0.2) finite element model. The head kinematics were used to calculate injury risks for seven head kinematics-based criteria: head angular velocity and acceleration, linear acceleration, head injury criterion (HIC), head impact power (HIP) and two versions of brain injury criterion (i.e., BRIC and BrIC). In addition, the intracranial responses were used to estimate seven tissue injury criteria, Von Mises stress, shear stress, coup pressure (C.P.) and countercoup pressure (CC.P.), maximum principal strain (MPS), cumulative strain damage measure (CSDM), and dilatation damage measure (DDM). A review of the medical reports for all cases indicated that each individual suffered severe head injuries and died. The injury risks predicted through simulations were compared to the head injuries recorded in the medical or forensic reports. The results indicated that 75-100% of the reconstructed ground impact accidents injuries were correctly predicted by angular acceleration, linear acceleration, HIC, C.P., MPS and CSDM0.15. Shear stress, CC.P. and CSDM0.25 correctly predicted 50-75% of the reconstructed accidents injuries. For angular velocity, HIP, BRIC and BrIC, the injuries were correctly predicted for less than 50% of the reconstructed accidents. The Von Mises stress and DDM did not correctly predict any reconstructed accidents injuries. The results could help to understand the effectiveness of the brain injury criteria for future head injury evaluation.

Trauma attenuating backing improves protection against behind armor blunt trauma.

BACKGROUND: Body armor is used by military personnel, police officers, and security guards to protect them from fatal gunshot injuries to the thorax. The protection against high-velocity weapons may, however, be insufficient. Complementary trauma attenuating backings (TAB) have been suggested to prevent morbidity and mortality in high-velocity weapon trauma. METHODS: Twenty-four Swedish landrace pigs, protected by a ceramid/aramid body armor without (n = 12) or with TAB (n = 12) were shot with a standard 7.62-mm assault rifle. Morphologic injuries, cardiorespiratory, and electroencephalogram changes as well as physical parameters were registered. RESULTS: The bullet impact caused a reproducible behind armor blunt trauma (BABT) in both the groups. The TAB significantly decreased size of the lung contusion and prevented hemoptysis. The postimpact apnea, desaturation, hypotension, and rise in pulmonary artery pressure were significantly attenuated in the TAB group. Moreover, TAB reduced transient peak pressures in thorax by 91%. CONCLUSIONS: Our results indicate that ordinary body armor should be complemented by a TAB to prevent thoracic injuries when the threat is high-velocity weapons.

Does injury pattern among major road trauma patients influence prehospital transport decisions regardless of the distance to the nearest trauma centre? - a retrospective study.

BACKGROUND: Prehospital undertriage occurs when the required level of care for a major trauma patient is underestimated and the patient is transported to a lower-level emergency care facility. One possible reason is that the pattern of injuries exceeding a certain severity threshold is not easily recognizable in the field. The present study aims to examine whether the injury patterns of major road trauma patients are associated with trauma centre transport decisions in Sweden, controlling for the distance from the crash to the nearest trauma centre and other patient characteristics. METHODS: The Swedish Traffic Accident Data Acquisition (STRADA) database was queried from April 2011 to March 2017. Teaching hospitals with neurosurgery capabilities were classified as trauma centres (TC), all other hospitals were classified as other emergency departments (ED). Injury Severity Score ≥ 13 was used as the threshold for major trauma. Ten common injury patterns were derived from the STRADA data; six patterns included serious neuro trauma to the head or spine. The remaining four patterns were: other severe injuries, moderate to serious abdomen injuries, serious thorax injuries and all other remaining injury patterns. Logistic regression was used to analyse the effect of injury patterns, age, sex and distance from crash to nearest TC on transport decision (TC or ED). RESULTS: Of the 2542 patients, 38.0% were transported to a TC, equating to a prehospital undertriage of 62%. Over half (59.4%) of the patients had four or more Abbreviated Injury Scale (AIS) 2+ injuries. After controlling for age, sex and distance to nearest TC, only patients sustaining serious head injuries together with other severe injuries had significantly higher odds of being transported to a TC (OR = 4.18, 95% CI: 2.03, 8.73). The odds of being transported to a TC decreased by 5% with every kilometre further away the crash location was to the nearest TC. CONCLUSION: These results highlight that there is considerable prehospital undertriage in Sweden and suggest that distance to nearest TC is more influential in transport decisions than injury pattern. These results can be used to further develop prehospital transportation guidelines and designation of trauma centres.

Passenger muscle responses in lane change and lane change with braking maneuvers using two belt configurations: Standard and reversible pre-pretensioner.

Objective: The introduction of integrated safety technologies in new car models calls for an improved understanding of the human occupant response in precrash situations. The aim of this article is to extensively study occupant muscle activation in vehicle maneuvers potentially occurring in precrash situations with different seat belt configurations. Methods: Front seat male passengers wearing a 3-point seat belt with either standard or pre-pretensioning functionality were exposed to multiple autonomously carried out lane change and lane change with braking maneuvers while traveling at 73 km/h. This article focuses on muscle activation data (surface electromyography [EMG] normalized using maximum voluntary contraction [MVC] data) obtained from 38 muscles in the neck, upper extremities, the torso, and lower extremities. The raw EMG data were filtered, rectified, and smoothed. All muscle activations were presented in corridors of mean ± one standard deviation. Separate Wilcoxon signed ranks tests were performed on volunteers' muscle activation onset and amplitude considering 2 paired samples with the belt configuration as an independent factor. Results: In normal driving conditions prior to any of the evasive maneuvers, activity levels were low (<2% MVC) in all muscles except for the lumbar extensors (3-5.5% MVC). During the lane change maneuver, selective muscles were activated and these activations restricted the sideway motions due to inertial loading. Averaged muscle activity, predominantly in the neck, lumbar extensor, and abdominal muscles, increased up to 24% MVC soon after the vehicle accelerated in lateral direction for all volunteers. Differences in activation time and amplitude between muscles in the right and left sides of the body were observed relative to the vehicle's lateral motion. For specific muscles, lane changes with the pre-pretensioner belt were associated with earlier muscle activation onsets and significantly smaller activation amplitudes than for the standard belt (P < .05). Conclusions: Applying a pre-pretensioner belt affected muscle activations; that is, amplitude and onset time. The present muscle activation data complement the results in a preceding publication, the volunteers' kinematics and the boundary conditions from the same data set. An effect of belt configuration was also seen on previously published volunteers' kinematics with lower lateral and forward displacements for head and upper torso using the pre-pretensioner belt versus the standard belt. The data provided in this article can be used for validation and further improvement of active human body models with active musculature in both sagittal and lateral loading scenarios intended for simulation of some evasive maneuvers that potentially occur prior to a crash.