Developing and assessing the measurement properties of an instrument to assess the impact of musculoskeletal pain in children aged 9 to 12-the pediatric musculoskeletal pain impact summary score.

BACKGROUND: Despite the high prevalence of musculoskeletal (MSK) pain in children, there is a lack of instruments to measure the impact of MSK pain on children's activity and participation. OBJECTIVE: To assess the reliability and construct validity of the Pediatric MSK Pain Impact summary score in school children (aged 9 to 12) with MSK pain. METHODS: We used a pragmatic approach in a reflective framework to assess internal consistency, structural validity, convergent validity, and discriminative validity in a sample of 615 children with MSK pain. RESULTS: The confirmatory factor analysis results indicate that the summary score has limited internal consistency and construct validity. The estimated Cronbach's alpha was 0.63, and most goodness of fit indices met the recommended thresholds (SRMR = 0.030; GFI = 0.993, CFI = 0.955, RMSEA 0.073), although they were close to the lower bounds of the thresholds. The convergent validity showed appropriate correlation of the summary score with quality of life (r = -0.33), care-seeking (r = 0.45), and medication intake (r = 0.37). Discriminative validity showed that the instrument can discriminate between the impact of pain on children with frequent and infrequent (2.93; 95% CI: 2.36 - 3.50) MSK pain. CONCLUSION: The Pediatric MSK Pain Impact summary showed limited internal consistency and construct validity; however, it can discriminate between children with frequent and infrequent pain. The results are promising for clinical and research practices as it is a short and convenient tool to be used in school-aged children.

A clinically relevant blunt spinal cord injury model in the regeneration competent axolotl (Ambystoma mexicanum) tail.

A randomized controlled and blinded animal trial was conducted in the axolotl (Ambystoma mexicanum), which has the ability to regenerate from transectional spinal cord injury (SCI). The objective of the present study was to investigate the axolotl's ability to regenerate from a blunt spinal cord trauma in a clinical setting. Axolotls were block-randomized to the intervention (n=6) or sham group (n=6). A laminectomy of two vertebrae at the level caudal to the hind limbs was performed. To induce a blunt SCI, a 25 g rod was released on the exposed spinal cord. Multiple modalities were applied at baseline (pre-surgery), and subsequently every third week for a total of 9 weeks. Gradient echo magnetic resonance imaging (MRI) was applied to assess anatomical regeneration. To support this non-invasive modality, regeneration was assessed by histology, and functional regeneration was investigated using swimming tests and functional neurological examinations. MRI suggested regeneration within 6 to 9 weeks. Histological analysis at 9 weeks confirmed regeneration; however, this regeneration was not complete. By the experimental end, all animals exhibited restored full neurological function. The present study demonstrated that the axolotl is capable of regenerating a contusion SCI; however, the duration of complete regeneration required further investigation.

2D and 3D Echocardiography in the Axolotl (Ambystoma Mexicanum).

Cardiac malfunction as a result of ischemic heart disease is a major challenge, and regenerative therapies to the heart are in high demand. A few model species such as zebrafish and salamanders that are capable of intrinsic heart regeneration hold promise for future regenerative therapies for human patients. To evaluate the outcome of cardioregenerative experiments it is imperative that heart function can be monitored. The axolotl salamander (A. mexicanum) represents a well-established model species in regenerative biology attaining sizes that allows for evaluation of cardiac function. The purpose of this protocol is to establish methods to reproducibly measure cardiac function in the axolotl using echocardiography. The application of different anesthetics (benzocaine, MS-222, and propofol) is demonstrated, and the acquisition of two-dimensional (2D) echocardiographic data in both anesthetized and unanesthetized axolotls is described. 2D echocardiography of the three-dimensional (3D) heart can suffer from imprecision and subjectivity of measurements, and to alleviate this phenomenon a solid method, namely intra/inter-operator/observer analysis, to measure and minimize this bias is demonstrated. Finally, a method to acquire 3D echocardiographic data of the beating axolotl heart at a very high spatiotemporal resolution and with pronounced blood-to-tissue contrast is described. Overall, this protocol should provide the necessary methods to evaluate cardiac function and model anatomy, and flow dynamics in the axolotl using ultrasound imaging with applications in both regenerative biology and general physiological experiments.