Identify Injury Mechanisms Research Articles

Evaluating the transcriptional landscape and cell-cell communication networks in chronically irradiated parotid glands

Understanding the transcriptional landscape that results in chronic salivary hypofunction after irradiation will help identify injury mechanisms and develop regenerative therapies. We present scRNA-seq analysis from control and irradiated murine parotid glands collected 10months after irradiation. We identify a population of secretory cells defined by specific expression of Etv1, which may be an acinar cell precursor. Acinar and Etv1+ secretory express Ntrk2 and Erbb3, respectively while the ligands for these receptors are expressed in myoepithelial and stromal cells. Furthermore, our data suggests that secretory cells and CD4+CD8+T-cells are the most transcriptionally affected during chronic injury with radiation, suggesting active immune involvement. Lastly, evaluation of cell-cell communication networks predicts that neurotrophin, neuregulin, ECM, and immune signaling are dysregulated after irradiation, and thus may play a role in the lack of repair. This resource will be helpful to understand cell-specific pathways that may be targeted to repair chronic damage in irradiated glands.

Assessing the biofidelity of in vitro biomechanical testing of the human cervical spine.

In vitro biomechanical studies of the osteoligamentous spine are widely used to characterize normal biomechanics, identify injury mechanisms, and assess the effects of degeneration and surgical instrumentation on spine mechanics. The objective of this study was to determine how well four standards in vitro loading paradigms replicate in vivo kinematics with regards to the instantaneous center of rotation and arthrokinematics in relation to disc deformation. In vivo data were previously collected from 20 asymptomatic participants (45.5 ± 5.8 years) who performed full range of motion neck flexion-extension (FE) within a biplane x-ray system. Intervertebral kinematics were determined with sub-millimeter precision using a validated model-based tracking process. Ten cadaveric spines (51.8 ± 7.3 years) were tested in FE within a robotic testing system. Each specimen was tested under four loading conditions: pure moment, axial loading, follower loading, and combined loading. The in vivo and in vitro bone motion data were directly compared. The average in vitro instant center of rotation was significantly more anterior in all four loading paradigms for all levels. In general, the anterior and posterior disc heights were larger in the in vitro models than in vivo. However, after adjusting for gender, the observed differences in disc height were not statistically significant. This data suggests that in vitro biomechanical testing alone may fail to replicate in vivo conditions, with significant implications for novel motion preservation devices such as cervical disc arthroplasty implants.

Epidemiology of injuries during the Wheelchair Basketball World Championships 2018: A prospective cohort study.

Several international sports federations have implemented a standardized injury reporting system during their championships. However, very few studies have investigated athletes with disabilities during major championships apart from the Paralympic Games. Therefore, the aim of this study was to assess the rate and characteristics of injuries during the Wheelchair Basketball World Championships 2018 (WBWC). This prospective cohort study was conducted during the WBWC held in Hamburg, Germany, from August 16 to August 26, 2018. Physicians or physiotherapists of all 28 participating teams (total 336 players) were asked to report all newly incurred injuries (with location, diagnosis, cause, and estimated duration of absence) daily on a standardized injury report form. Prevalence and incidence rates were calculated. Medical staff of 11 teams (132 players) reported 100 injuries, equivalent to 75.8 per 100 players (95% CI: 60.9-90.7) or 68.9 per 1000 player-days (55.4-82.4). Eight time-loss injuries were reported (6.1 injuries per 100 players [95% CI: 1.9-10.3] or 5.5 injuries per 1000 player-days [1.7-9.3]). More injuries were incurred during matches (n=68) than during training. Most injuries affected the neck/cervical spine (16%), thoracic spine/upper back (15%), and shoulder (14%). The most frequent diagnosis was muscle spasms (25%), the most frequent cause was overuse (52%). A high rate of non-time-loss injuries compared to Paralympic Games was reported. Future studies should focus on the etiology of muscle spasms and further identify injury mechanisms of traumatic and overuse injuries in wheelchair basketball players to develop adequate preventive measures.

An Evidence-Based Discussion of Heading the Ball and Concussions in High School Soccer.

Soccer, originally introduced as a safer sport for children and adolescents, has seen a rapid increase in popularity in the United States over the past 3 decades. Recently, concerns have been raised regarding the safety of soccer ball heading (when an athlete attempts to play the ball in the air with his or her head) given the rise in concussion rates, with some calling for a ban on heading among soccer players younger than 14 years. To evaluate trends over time in boys' and girls' soccer concussions, to identify injury mechanisms commonly leading to concussions, to delineate soccer-specific activities during which most concussions occur, to detail heading-related soccer concussion mechanisms, and to compare concussion symptom patterns by injury mechanism. Retrospective analysis of longitudinal surveillance data collected from 2005-2006 through 2013-2014 in a large, nationally representative sample of US high schools. Participants were boys and girls who were high school soccer players. Concussions sustained during high school-sanctioned soccer games and practices. Mechanism and sport-specific activity of concussion. Overall, 627 concussions were sustained during 1,393,753 athlete exposures (AEs) among girls (4.50 concussions per 10,000 AEs), and 442 concussions were sustained during 1,592,238 AEs among boys (2.78 concussions per 10,000 AEs). For boys (68.8%) and girls (51.3%), contact with another player was the most common concussion mechanism. Heading was the most common soccer-specific activity, responsible for 30.6% of boys' concussions and 25.3% of girls' concussions. Contact with another player was the most common mechanism of injury in heading-related concussions among boys (78.1%) and girls (61.9%). There were few differences in concussion symptom patterns by injury mechanism. Although heading is the most common activity associated with concussions, the most frequent mechanism was athlete-athlete contact. Such information is needed to drive evidence-based, targeted prevention efforts to effectively reduce soccer-related concussions. Although banning heading from youth soccer would likely prevent some concussions, reducing athlete-athlete contact across all phases of play would likely be a more effective way to prevent concussions as well as other injuries.

Establishment of quantitative severity evaluation model for spinal cord injury by metabolomic fingerprinting.

Spinal cord injury (SCI) is a devastating event with a limited hope for recovery and represents an enormous public health issue. It is crucial to understand the disturbances in the metabolic network after SCI to identify injury mechanisms and opportunities for treatment intervention. Through plasma 1H-nuclear magnetic resonance (NMR) screening, we identified 15 metabolites that made up an “Eigen-metabolome” capable of distinguishing rats with severe SCI from healthy control rats. Forty enzymes regulated these 15 metabolites in the metabolic network. We also found that 16 metabolites regulated by 130 enzymes in the metabolic network impacted neurobehavioral recovery. Using the Eigen-metabolome, we established a linear discrimination model to cluster rats with severe and mild SCI and control rats into separate groups and identify the interactive relationships between metabolic biomarkers in the global metabolic network. We identified 10 clusters in the global metabolic network and defined them as distinct metabolic disturbance domains of SCI. Metabolic paths such as retinal, glycerophospholipid, arachidonic acid metabolism; NAD–NADPH conversion process, tyrosine metabolism, and cadaverine and putrescine metabolism were included. In summary, we presented a novel interdisciplinary method that integrates metabolomics and global metabolic network analysis to visualize metabolic network disturbances after SCI. Our study demonstrated the systems biological study paradigm that integration of 1H-NMR, metabolomics, and global metabolic network analysis is useful to visualize complex metabolic disturbances after severe SCI. Furthermore, our findings may provide a new quantitative injury severity evaluation model for clinical use.

Evaluation of spinal cord injury animal models.

Because there is no curative treatment for spinal cord injury, establishing an ideal animal model is important to identify injury mechanisms and develop therapies for individuals suffering from spinal cord injuries. In this article, we systematically review and analyze various kinds of animal models of spinal cord injury and assess their advantages and disadvantages for further studies.

The Response of Pediatric Ribs to Quasi-static Loading: Mechanical Properties and Microstructure

Traumatic injury is a major cause of death in the child population. Motor vehicle crashes account for a large portion of these deaths, and a considerable effort is put forth by the safety community to identify injury mechanisms and methods of injury prevention. However, construction of biofidelic anthropomorphic test devices and computational models for this purpose requires knowledge of bone properties that is difficult to obtain. The objective of this study is to characterize the relationship between mechanical properties and measures of skeletal development in the growing rib. Anterolateral segments of 44 ribs from 12 pediatric individuals (age range: 5 months to 9 years) were experimentally tested in three-point bending. Univariate mixed models were used to assess the predictive abilities of development-related variables (e.g., age, stature, histomorphometry, cross-sectional geometry) on mechanical variables (material and structural properties). Results show that stature, in addition to age, may be a reliable predictor of bone strength, and that histomorphometry has potential to explain bone properties and to further our understanding of fracture mechanisms. For example, percent secondary lamellar bone (%Sd.Ar) successfully predicts peak force (F P) and Young's modulus (E). Application of these findings is not restricted to injury biomechanics, but can also be referenced in forensic and anthropological contexts.

A Comprehensive Renal Injury Concept Based on a Validated Finite Element Model of the Human Abdomen

The identification of abdominal injury mechanisms, development of effective countermeasures, and refinement of clinical approach to injury treatment are greatly facilitated by the employment of numerical models that can predict injuries resulting from complicated soft tissue interactions during blunt abdominal impact. The present study introduces a detailed three-dimensional finite element model of the human abdomen that was developed specifically for the investigation of renal trauma. The model geometry and materials reflect the complex mechanical environment of the abdomen, and is validated against both published and novel experiments. It is shown that use of the proposed model, in combination with appropriate mechanical organ injury criteria, provides a significant step toward a comprehensive renal injury concept. Specifically, the abdominal model offers the possibility to investigate injury likelihood and identify injury mechanisms over a broad range of impact loading scenarios. A sophisticated numerical model of renal trauma has been developed that can be used to effectively predict renal injury outcome for lateral impact.

Injury hospitalizations of pregnant women in the United States, 2002

To estimate the number of injury-related hospitalizations of pregnant women in the United States and to identify injury mechanisms associated with hospitalizations that end in delivery. Using data on injury hospitalizations of pregnant women from the 2002 Healthcare Cost and Utilization Project Nationwide Inpatient Sample, we compared the mechanism of injuries of nondelivery hospitalizations with those of delivery hospitalizations. Of an estimated 16,982 injury hospitalizations involving pregnant women in 2002, a delivery occurred in 37.7%. Hospitalizations with injuries caused by overexertion had significantly increased odds of including delivery (odds ratio OR 4.55, confidence interval 95% CI 2.21-9.39) compared with hospitalizations with other causes of injury. Hospitalizations with injuries caused by motor vehicle traffic (OR 0.36, 95% CI 0.23-0.58) had significantly lower odds of including delivery. We estimated that there were 4.1 injury hospitalizations of pregnant women per 1000 deliveries in 2002. The majority of injury mechanisms did not significantly increase the odds of the hospitalization ending in delivery. Providers should broaden injury prevention messages to address poisonings and overexertion.

Tonic Finite Element Model of the Lower Limb

It is widely admitted that muscle bracing influences the result of an impact, facilitating fractures by enhancing load transmission and reducing energy dissipation. However, human numerical models used to identify injury mechanisms involved in car crashes hardly take into account this particular mechanical behavior of muscles. In this context, in this work we aim to develop a numerical model, including muscle architecture and bracing capability, focusing on lower limbs. The three-dimensional (3-D) geometry of the musculoskeletal system was extracted from MRI images, where muscular heads were separated into individual entities. Muscle mechanical behavior is based on a phenomenological approach, and depends on a reduced number of input parameters, i.e., the muscle optimal length and its corresponding maximal force. In terms of geometry, muscles are modeled with 3-D viscoelastic solids, guided in the direction of fibers with a set of contractile springs. Validation was first achieved on an isolated bundle and then by comparing emergency braking forces resulting from both numerical simulations and experimental tests on volunteers. Frontal impact simulation showed that the inclusion of muscle bracing in modeling dynamic impact situations can alter bone stresses to potentially injury-inducing levels.