Effects of Training and Overtraining on Intervertebral Disc Proteoglycans

Study Design. Animal experimental study. Objective. Evaluate the effect of physical activity and overtraining condition on glycosaminoglycan concentration on the intervertebral disc (IVD) using a rat running model. Summary of Background Data. Some guidelines recommend the implementation of a physical exercise program as treatment for low back pain however, cyclic loading impact on the health of the IVD and whether there is a dose-response relationship is still incompletely understood. Methods. Thirty-two rats ages 8 weeks were divided into four groups with eight animals each. The first 8 weeks were the adaptive phase, the overtraining phase was from the ninth to the eleventh week, which consisted of increasing the number of daily training sessions from 1 to 4 and the recovery phase was represented by the 12th and 13th weeks without training. Control group 1 (CG1) did not undergo any kind of training. Control group 2 (CG2) completed just the adaptive phase. Overtraining group 1 (OT1) completed the overtraining phase. Overtraining group 2 (OT2) completed the recovery phase. Running performance tests were used to assess the "overtraining'' status of the animals. IVD glycosaminoglycans were extracted and quantified, and identified by electrophoresis. Results. Glycosaminoglycans showed a distribution between chondroitin sulfate and dermatan sulfate. Glycosaminoglycans quantification showed decreasing concentration at the following order: OT1 > CG2 > OT2 > CG1. Increased expression of dermatan sulfate was verified at the groups submitted to any training. Conclusion. Overtraining condition, as assessed by muscle and cardiovascular endurance did not lessen glycosaminoglycan concentration in the IVD. In fact, physical exercise increased glycosaminoglycan concentration in the IVD in proportion to the training load, even at overtraining condition, returning to normal levels after the recovery phase and glycosaminoglycan production is a reversible acute positive response for mechanical stimulation of the IVD.Univ Fed Sao Paulo, Dept Orthopaed & Traumatol, Escola Paulista Med, Rua Borges Lagoa,783-5 Andar Vila Clementino, BR-04038032 Sao Paulo, SP, BrazilUniv Fed Juiz de Fora, Dept Biochem, Juiz De Fora, MG, BrazilUniv Fed Sao Paulo, Dept Biochem, Escola Paulista Med, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Orthopaed & Traumatol, Escola Paulista Med, Rua Borges Lagoa,783-5 Andar Vila Clementino, BR-04038032 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Biochem, Escola Paulista Med, Sao Paulo, SP, BrazilWeb of Scienc

Sensitivity analysis and optimization of sub-wavelength optical gratings using adjoints

Background: Humeral shaft fractures account for 1 to 3% of all fractures in adults and for 20% of all humeral fractures. Non-operative treatment is still the standard treatment of isolated humeral shaft fractures, although this method can present unsatisfactory results. Surgical treatment is reserved for specific conditions. Modern concepts of internal fixation of long bone shaft fractures advocate relative stabilisation techniques with no harm to fracture zone. Recently described, minimally invasive bridge plate osteosynthesis has been shown to be a secure technique with good results for treating humeral shaft fractures. There is no good quality evidence advocating which method is more effective. This randomised controlled trial will be performed to investigate the effectiveness of surgical treatment of humeral shaft fractures with bridge plating in comparison with conservative treatment with functional brace.Methods/Design: This randomised clinical trial aims to include 110 patients with humeral shaft fractures who will be allocated after randomisation to one of the two groups: bridge plate or functional brace. Surgical treatment will be performed according to technique described by Livani and Belangero using a narrow DCP plate. Non-operative management will consist of a functional brace for 6 weeks or until fracture consolidation. All patients will be included in the same rehabilitation program and will be followed up for 1 year after intervention. the primary outcome will be the DASH score after 6 months of intervention. As secondary outcomes, we will assess SF-36 questionnaire, treatment complications, Constant score, pain (Visual Analogue Scale) and radiographs.Discussion: According to current evidence shown in a recent systematic review, this study is one of the first randomised controlled trials designed to compare two methods to treat humeral shaft fractures (functional brace and bridge plate surgery)