Deep dermal burn injury results in scarless wound healing in the ovine fetus

Early to mid-term fetuses heal cutaneous incisional wounds without scars; however, fetal response to burn injury has not been ascertained. We present a fetal model of thermal injury and subsequent analysis of fetal and lamb response to burn injury. A reproducible deep dermal burn injury was created in the fetus by application of water at 66 degrees C for 7 seconds, and at 82 degrees C for 10 seconds to the lamb. Macroscopically, the area of fetal scald was undetectable from day 7 post injury, while all lamb scalds were readily identified and eventually healed with scarring. Using a five-point histopathology scoring system for alteration in tissue morphology, differences were detected between control and scalded skin at all stages in lamb postburn, but no difference was detected in the fetal model after day 7. There were also large differences in content of alpha-smooth muscle actin and transforming growth factor-beta1 between control and scalded lamb and these differences were statistically significant at day 14 (P < 0.01). This novel model of fetal and lamb response to deep dermal injury indicates that the fetus heals a deep burn injury in a scarless fashion. Further elucidation of this specific fetal process of burn injury repair may lead to improved outcome for patients with burn injury.

Interleukin-1beta induces human proximal tubule cell injury, alpha-smooth muscle actin expression and fibronectin production

BACKGROUND Tubulointerstitial lesions, characterized by tubular injury, interstitial fibrosis and the appearance of myofibroblasts, are the strongest predictors of the degree and progression of chronic renal failure. These lesions are typically preceded by macrophage infiltration of the tubulointerstitium, raising the possibility that these inflammatory cells promote progressive renal disease through fibrogenic actions on resident tubulointerstitial cells. The aim of the present study, therefore, was to investigate the potentially fibrogenic mechanisms of interleukin-1beta (IL-1beta), a macrophage-derived pro-inflammatory cytokine, on human proximal tubule cells (PTC). METHODS Confluent, quiescent, passage 2 PTC were established in primary culture from histologically normal segments of human renal cortex (N = 11) and then incubated in serum- and hormone-free media supplemented with either IL-1beta (0 to 4 ng/mL) or vehicle (control). RESULTS IL-1beta significantly enhanced fibronectin secretion by up to fourfold in a time- and concentration-dependent fashion. This was accompanied by significant (2.5- to 6-fold) increases in alpha-smooth muscle actin (alpha-SMA) expression, transforming growth factor beta (TGF-beta1) secretion, nitric oxide (NO) production, NO synthase 2 (NOS2) mRNA and lactate dehydrogenase (LDH) release. Cell proliferation was dose-dependently suppressed by IL-1beta. NG-methyl-l-arginine (L-NMMA; 1 mmol/L), a specific inhibitor of NOS, blocked NO production but did not alter basal or IL-1beta-stimulated fibronectin secretion. In contrast, a pan-specific TGF-beta neutralizing antibody significantly blocked the effects of IL-1beta on PTC fibronectin secretion (IL-1beta, 268.1 +/- 30.6 vs. IL-1beta+alphaTGF-beta 157.9 +/- 14.4%, of control values, P < 0.001) and DNA synthesis (IL-1beta 81.0 +/- 6.7% vs. IL-1beta+alphaTGF-beta 93.4 +/- 2.1%, of control values, P < 0.01). CONCLUSION IL-1beta acts on human PTC to suppress cell proliferation, enhance fibronectin production and promote alpha-smooth muscle actin expression. These actions appear to be mediated by a TGF-beta1 dependent mechanism and are independent of nitric oxide release.

A novel method using intranasal delivery of EdU demonstrates that accessory olfactory ensheathing cells respond to injury by proliferation

Olfactory ensheathing cells (OECs) play an important role in the continuous regeneration of the primary olfactory nervous system throughout life and for regeneration of olfactory neurons after injury. While it is known that several individual OEC subpopulations with distinct properties exist in different anatomical locations, it remains unclear how these different subpopulations respond to a major injury. We have examined the proliferation of OECs from one distinct location, the peripheral accessory olfactory nervous system, following large-scale injury (bulbectomy) in mice. We used crosses of two transgenic reporter mouse lines, S100ß-DsRed and OMP-ZsGreen, to visualise OECs, and main/accessory olfactory neurons, respectively. We surgically removed one olfactory bulb including the accessory olfactory bulb to induce degeneration, and found that accessory OECs in the nerve bundles that terminate in the accessory olfactory bulb responded by increased proliferation with a peak occurring 2 days after the injury. To label proliferating cells we used the thymidine analogue ethynyl deoxyuridine (EdU) using intranasal delivery instead of intraperitoneal injection. We compared and quantified the number of proliferating cells at different regions at one and four days after EdU labelling by the two different methods and found that intranasal delivery method was as effective as intrapeitoneal injection. We demonstrated that accessory OECs actively respond to widespread degeneration of accessory olfactory axons by proliferating. These results have important implications for selecting the source of OECs for neural regeneration therapies and show that intranasal delivery of EdU is an efficient and reliable method for assessing proliferation of olfactory glia.

The effect of varying diagnostic terminology within patient discharge information on expected mild traumatic brain injury outcome

This study aimed to determine if systematic variation of the diagnostic terminology embedded within written discharge information (i.e., concussion or mild traumatic brain injury, mTBI) would produce different expected symptoms and illness perceptions. We hypothesized that compared to concussion advice, mTBI advice would be associated with worse outcomes. Sixty-two volunteers with no history of brain injury or neurological disease were randomly allocated to one of two conditions in which they read a mTBI vignette followed by information that varied only by use of the embedded terms concussion (n = 28) or mTBI (n = 34). Both groups reported illness perceptions (timeline and consequences subscale of the Illness Perception Questionnaire-Revised) and expected Postconcussion Syndrome (PCS) symptoms 6 months post injury (Neurobehavioral Symptom Inventory, NSI). Statistically significant group differences due to terminology were found on selected NSI scores (i.e., total, cognitive and sensory symptom cluster scores (concussion > mTBI)), but there was no effect of terminology on illness perception. When embedded in discharge advice, diagnostic terminology affects some but not all expected outcomes. Given that such expectations are a known contributor to poor mTBI outcome, clinicians should consider the potential impact of varied terminology on their patients.

Analysis of traffic injury severity in Dhaka, Bangladesh

This research identifies roadway, traffic, and environmental factors that influence the injury severity of road traffic crashes in Dhaka. Dhaka provides a rather unusual driving risk environment to study, since virtually anyone can obtain a drivers’ license and very little traffic enforcement and fines are given when drivers violate traffic rules. To examine this city with presumed heightened crash severity risk, police reported crash data from 2007 to 2011 containing about 2714 road traffic crashes were collected. The injury severity of traffic crashes—recorded as either fatal, serious injury, or property damage only—were modeled using an ordered Probit model. Significant factors increasing the probability of fatal injuries include crashes along highways (65%), absence of a road divider (80%), crashes during night time (54%), and vehicle-pedestrian collisions (367%); whereas two-way traffic configuration (21%), and traffic police controlled schemes (41%) decrease the probability of fatalities. Both similarities and differences of the findings between crash risk in Dhaka and developed countries are discussed in policy relevant terms.

Control strategies to prevent total hip replacement-related infections : a systematic review and mixed treatment comparison

OBJECTIVE: To synthesise the available evidence and estimate the comparative efficacy of control strategies to prevent total hip replacement (THR)-related surgical site infections (SSIs) using a mixed treatment comparison. DESIGN: Systematic review and mixed treatment comparison. SETTING: Hospital and other healthcare settings. PARTICIPANTS: Patients undergoing THR. PRIMARY AND SECONDARY OUTCOME MEASURES: The number of THR-related SSIs occurring following the surgical operation. RESULTS: 12 studies involving 123 788 THRs and 9 infection control strategies were identified. The strategy of 'systemic antibiotics+antibiotic-impregnated cement+conventional ventilation' significantly reduced the risk of THR-related SSI compared with the referent strategy (no systemic antibiotics+plain cement+conventional ventilation), OR 0.13 (95% credible interval (CrI) 0.03-0.35), and had the highest probability (47-64%) and highest median rank of being the most effective strategy. There was some evidence to suggest that 'systemic antibiotics+antibiotic-impregnated cement+laminar airflow' could potentially increase infection risk compared with 'systemic antibiotics+antibiotic-impregnated cement+conventional ventilation', 1.96 (95% CrI 0.52-5.37). There was no high-quality evidence that antibiotic-impregnated cement without systemic antibiotic prophylaxis was effective in reducing infection compared with plain cement with systemic antibiotics, 1.28 (95% CrI 0.38-3.38). CONCLUSIONS: We found no convincing evidence in favour of the use of laminar airflow over conventional ventilation for prevention of THR-related SSIs, yet laminar airflow is costly and widely used. Antibiotic-impregnated cement without systemic antibiotics may not be effective in reducing THR-related SSIs. The combination with the highest confidence for reducing SSIs was 'systemic antibiotics+antibiotic-impregnated cement+conventional ventilation'. Our evidence synthesis underscores the need to review current guidelines based on the available evidence, and to conduct further high-quality double-blind randomised controlled trials to better inform the current clinical guidelines and practice for prevention of THR-related SSIs.

Psychological predictors of injury among elite athletes

Objectives: To establish injury rates among a population of elite athletes, to provide normative data for psychological variables hypothesised to be predictive of sport injuries, and to establish relations between measures of mood, perceived life stress, and injury characteristics as a precursor to introducing a psychological intervention to ameliorate the injury problem. Methods: As part of annual screening procedures, athletes at the Queensland Academy of Sport report medical and psychological status. Data from 845 screenings (433 female and 412 male athletes) were reviewed. Population specific tables of normative data were established for the Brunel mood scale and the perceived stress scale. Results: About 67% of athletes were injured each year, and about 18% were injured at the time of screening. Fifty percent of variance in stress scores could be predicted from mood scores, especially for vigour, depression, and tension. Mood and stress scores collectively had significant utility in predicting injury characteristics. Injury status (current, healed, no injury) was correctly classified with 39% accuracy, and back pain with 48% accuracy. Among a subset of 233 uninjured athletes (116 female and 117 male), five mood dimensions (anger, confusion, fatigue, tension, depression) were significantly related to orthopaedic incidents over the preceding 12 months, with each mood dimension explaining 6–7% of the variance. No sex differences in these relations were found. Conclusions: The findings support suggestions that psychological measures have utility in predicting athletic injury, although the relatively modest explained variance highlights the need to also include underlying physiological indicators of allostatic load, such as stress hormones, in predictive models.

Psychological screening and injury among elite athletes

The purpose of the present investigation was to evaluate the effectiveness of the psychological component of the Queensland Academy of Sport (QAS) Health Screening Questionnaire in screening for injury/illness characteristics among elite athletes. In total, 793 scholarship athletes (409 females and 384 males) ranging in age from 11 to 41 years (M = 19, SD = 4.4) across 20 sports at the QAS in Brisbane, Australia, completed the QAS Health Screening Questionnaire. Psychological risk factors examined were life stress and mood, as measured by the Perceived Stress Scale - 10 (PSS-10) and the Brunel Mood Scale (BRUMS) respectively, in addition to disordered eating behaviours and history of diagnosed psychological disorders. Medical risk factors examined included asthma and back pain. Single-factor MANOVAs showed multivaritate effects for injury, second injury, back pain, asthma, anxiety disorder diagnosis, and fasting. Discriminant function analyses demonstrated that life stress and mood scores had significant utility in correctly classifying injury and second injury status, asthma, back pain, anxiety, and eating disorder diagnosis, in addition to the use of fasting and vomiting as weight control methods. The present findings suggest that the psychology component of the QAS Health Screening Questionnaire demonstrates significant utility as a screening tool regarding injury/illness characteristics among elite athletes.

Safety climate and injury occurrence of repair, maintenance, minor alteration and addition works : a comparison of workers, supervisors and managers

Purpose The repair, maintenance, minor alteration and addition (RMAA) sector has been expanding in many developed cities. Safety problems of the RMAA sector have attracted the attention of many governments. This study has the objectives of comparing the level of safety climate of workers, supervisors and managers in the RMAA sector; and explaining/ predicting the impact of safety climate on injury occurrence of workers, supervisors and managers. Design/methodology/approach A questionnaire survey was administered to RMAA contracting companies in Hong Kong. Findings When comparing the safety climate perception of workers, supervisors and managers in the RMAA sector, the supervisors group had the lowest mean safety climate score. Results showed that a positive workforce safety attitude and acceptance of safety rules and regulations reduced the workers’ likelihood of having injuries. A reasonable production schedule led to a lower probability of supervisors being injured. Management commitment and effective safety management reduced the probability of managers being injured. Originality/value This study revealed variations of safety climate at the different levels in the organizational hierarchy and their varying influence on safety performance of the RMAA sector. Safety of RMAA works could be improved by promulgating specific safety measures at the different hierarchy levels.

Design of a traumatic injury simulator for assessing lower limb response to high loading rates

Current military conflicts are characterized by the use of the improvised explosive device. Improvements in personal protection, medical care, and evacuation logistics have resulted in increasing numbers of casualties surviving with complex musculoskeletal injuries, often leading to lifelong disability. Thus, there exists an urgent requirement to investigate the mechanism of extremity injury caused by these devices in order to develop mitigation strategies. In addition, the wounds of war are no longer restricted to the battlefield; similar injuries can be witnessed in civilian centers following a terrorist attack. Key to understanding such mechanisms of injury is the ability to deconstruct the complexities of an explosive event into a controlled, laboratory-based environment. In this article, a traumatic injury simulator, designed to recreate in the laboratory the impulse that is transferred to the lower extremity from an anti-vehicle explosion, is presented and characterized experimentally and numerically. Tests with instrumented cadaveric limbs were then conducted to assess the simulator’s ability to interact with the human in two mounting conditions, simulating typical seated and standing vehicle passengers. This experimental device will now allow us to (a) gain comprehensive understanding of the load-transfer mechanisms through the lower limb, (b) characterize the dissipating capacity of mitigation technologies, and (c) assess the bio-fidelity of surrogates.

A standing vehicle occupant is likely to sustain a more severe injury than one who has flexed knees in an under‐vehicle explosion : a cadaveric study

The lower limb of military vehicle occupants has been the most injured body part due to undervehicle explosions in recent conflicts. Understanding the injury mechanism and causality of injury severity could aid in developing better protection. Therefore, we tested 4 different occupant postures (seated, brace, standing, standing with knee locked in hyper‐extension) in a simulated under‐vehicle explosion (solid blast) using our traumatic injury simulator in the laboratory; we hypothesised that occupant posture would affect injury severity. No skeletal injury was observed in the specimens in seated and braced postures. Severe, impairing injuries were observed in the foot of standing and hyper‐extended specimens. These results demonstrate that a vehicle occupant whose posture at the time of the attack incorporates knee flexion is more likely to be protected against severe skeletal injury to the lower leg.

Use of cadavers and anthropometric test devices (ATDs) for assessing lower limb injury outcome from under‐vehicle explosions

Lower extremities are particularly susceptible to injury in an under‐vehicle explosion. Operational fitness of military vehicles is assessed through anthropometric test devices (ATDs) in full‐scale blast tests. The aim of this study was to compare the response between the Hybrid‐III ATD, the MiL‐Lx ATD and cadavers in our traumatic injury simulator, which is able to replicate the response of the vehicle floor in an under‐vehicle explosion. All specimens were fitted with a combat boot and tested on our traumatic injury simulator in a seated position. The load recorded in the ATDs was above the tolerance levels recommended by NATO in all tests; no injuries were observed in any of the 3 cadaveric specimens. The Hybrid‐III produced higher peak forces than the MiL‐Lx. The time to peak strain in the calcaneus of the cadavers was similar to the time to peak force in the ATDs. Maximum compression of the sole of the combat boot was similar for cadavers and MiL‐Lx, but significantly greater for the Hybrid‐III. These results suggest that the MiL‐Lx has a more biofidelic response to under‐vehicle explosive events compared to the Hybrid‐III. Therefore, it is recommended that mitigation strategies are assessed using the MiL‐Lx surrogate and not the Hybrid‐III.

Periprosthetic fracture torque for short versus standard cemented hip stems : an experimental in vitro study

In an attempt to preserve proximal femoral bone stock and achieve a better fit in smaller femora, especially in the Asian population, several new shorter stem designs have become available. We investigated the torque to periprosthetic femoral fracture of the Exeter short stem compared with the conventional length Exeter stem in a Sawbone model. 42 stems; 21 shorter and 21 conventional stems both with three different offsets were cemented in a composite Sawbone model and torqued to fracture. Results showed that Sawbone femurs break at a statistically significantly lower torque to failure with a shorter compared to conventional length Exeter stem of the same offset. Both standard and short stem designs are safe to use as the torque to failure is 7-10 times that seen in activities of daily living.