New opto-electro-mechanical sensor for two-dimensions dosimetry based on radiochromic films.

This work presents the validation of a new Opto‒Electro-Mechanical (MOEM) system consisting of a matrix of photodetectors for two-dimensional dosimetry evaluation with radiochromic films. The proposed system is based on a 5 × 10 matrix of photodetectors controlled by both in-house electronic circuit and graphical user interface, which enables optical measurements directly. We present the first tests performed in an X-ray machine and 137Cs source with that array by using Gafchromic EBT3 films. We obtained similar results than with a standard method (e.g. flat-bed scanner). Results were compared with Monte Carlo simulations and very good agreement was found. Results show the feasibility of using this system for dose evaluations. To the best of our knowledge, this is the first MOEM sensor for radiotherapy. Further developments are ongoing to create an advanced 16 × 16 LDRs system covering 1.6 cm × 1.6 cm with a 1 mm of spatial resolution. We point to develop a portable dosimetry tool delivering dose maps in real time to improve the clinical application of radiochromic films.

Effects of long-term periodized resistance training on body composition, leptin, resistin and muscle strength in elderly post-menopausal women.

AIM: Objective of the study was to determine the effects of a periodized resistance training program on body composition, plasmatic levels of leptin and resistin, and muscle strength in elderly post-menopausal women. METHODS: Twenty-three post-menopausal women (age= 63.02±4.42 years; height 1.55±0.06 m; body mass 67.56±2.26 kg) were submitted to 12 months of periodized resistance training twice a week. The training program consisted of 3 sets of 6-14 repetitions maximal (RM). Body composition (DXA), muscle strength (bench press, leg press 45º and arm curl), plasmatic levels of resistin and leptin (ELISA method) were assessed before and after the training program. Paired Student's t test was used for comparison between pre- and post-training values. RESULTS: There was a significant increase in muscle strength and lean body mass; decrease in body mass, body fat percentage and fat mass after 12 months of resistance training, a part from the decrease in leptin and resistin levels. CONCLUSION: Long-term periodized resistance training prevents aging sarcopenia, decreases body fat and systemic markers of inflammation in postmenopausal elderly women.

Effects of resistance training on matrix metalloproteinase-2 activity and biomechanical and physical properties of bone in ovariectomized and intact rats.

The purpose of this study was to investigate the influence of resistance training on the activity of matrix metalloproteinase (MMP)-2 and bone biomechanical properties in ovariectomized and intact rats. Forty-eight female rats were divided into two distinct groups, ovariectomized (OVX) and intact (Int), which were subdivided into three similar subgroups: sedentary, acute exercise and chronic exercise. Rats performed a resistance training for 12 weeks in which animals climbed a vertical ladder of 1.1 m with weights attached to their tails. Sessions were performed with an interval of 3, 4-9 and 8-12 days scaled dynamic movements of climbing. Biomechanical and physical analyses were performed using a universal testing machine, and MMP-2 activity analysis by zymography. Bone density (BD), mineral density (MD), maximum load and fracture load was reduced in sedentary and acute exercise OVX groups compared with the sedentary intact group (P<0.05); in contrast, chronically trained groups (OVX and Int) showed a significant increase in BD, MD and fracture load compared with all the other groups. MMP-2 activity in chronically trained groups also showed a significant increase, while the sedentary OVX group showed a decrease in MMP-2 activity compared with the intact sedentary group (P<0.05). Our results suggest that the resistance training proposed in our work was efficient in reverting the deleterious effects of ovariectomy on bone tissue, and also produced modeling effects in intact rats. On the other hand, ovariectomy reduced the activity of MMP-2 and produced deleterious effects on bone tissue, mimicking menopause intrinsically.