Combined effects of exercise and propranolol on bone tissue in ovariectomized rats.

The bone response to physical exercise may be under control of the SNS. Using a running session in rats, we confirmed that exercise improved trabecular and cortical properties. SNS blockade by propranolol did not affect this response on cortical bone but surprisingly inhibited the trabecular response. This suggests that the SNS is involved in the trabecular response to exercise but not in the cortical response. INTRODUCTION: Animal studies have suggested that bone remodeling is under beta-adrenergic control through the sympathetic nervous system (SNS). However, the SNS contribution to bone response under mechanical loading remains unclear. The purpose of this study was to examine the preventive effect of exercise coupled with propranolol on cancellous and cortical bone compartments in ovariectomized rats. MATERIALS AND METHODS: Six-month-old female Wistar rats were ovariectomized (OVX, n = 44) or sham-operated (n = 24). OVX rats received subcutaneous injections of propranolol 0.1 mg/kg/day or vehicle and were submitted or not submitted to treadmill exercise (13 m/minute, 60 minutes/day, 5 days/week) for 10 weeks. Tibial and femoral BMD was analyzed longitudinally by DXA. At death, the left tibial metaphysis and L(4) vertebrae were removed, and microCT was performed to study trabecular and cortical bone structure. Histomorphometric analysis was performed on the right proximal tibia. RESULTS: After 10 weeks, BMD and trabecular strength decreased in OVX rats, whereas bone turnover rate and cortical porosity increased compared with the Sham group (p < 0.001). Either propranolol or exercise allowed preservation of bone architecture by increasing trabecular number (+50.35% versus OVX; p < 0.001) and thickness (+16.8% versus OVX; p < 0.001). An additive effect of propranolol and exercise was observed on cortical porosity but not on trabecular microarchitecture or cortical width. Biomechanical properties indicated a higher ultimate force in the OVX-propranolol-exercise group compared with the OVX group (+9.9%; p < 0.05), whereas propranolol and exercise alone did not have any significant effect on bone strength. CONCLUSIONS: Our data confirm a contribution of the SNS to the determinants of bone mass and quality and show a antagonistic effect of exercise and a beta-antagonist on trabecular bone structure.     

Troubles alimentaires,désirabilité sociale,insatisfaction corporelle et estime de soi physique chez des étudiantes de première année

Objectives

The relation between the subject and its own body seems to be problematic in Eating Disorders. This study aims to better understand eating disorders in non-clinical population, by focusing on social desirability, body dissatisfaction and physical self-esteem. The students represent a high-risk population for eating disorders. These latters usually begin during this period, especially in the first years of study. Weight control as observed in eating disorders could report for the tendency of the individual to seek peers’ approval and could reflect a need to respond to a “social desirability”. It seems important to grasp the concerns of body image by focusing on the individual's perception of his body and the value it assigns. This research deals with eating behaviours disturbances and focuses, on the one hand, on body dissatisfaction, on the other hand, on the analysis of the role of different physical self-esteem dimensions on these behaviours. In addition we explore the relationship between social desirability, body dissatisfaction and eating disorders. We wish to bring light on individuals’ body perception within the framework of eating behaviours disturbance.

Comprehensive analysis of PTEN status in breast carcinomas

PTEN plays a well‐established role in the negative regulation of the PI3K pathway, which is frequently activated in several cancer types, including breast cancer. A nuclear function in the maintenance of chromosomal stability has been proposed for PTEN but is yet to be clearly defined. In order to improve understanding of the role of PTEN in mammary tumorigenesis in terms of a possible gene dosage effect, its PI3K pathway function and its association with p53, we undertook comprehensive analysis of PTEN status in 135 sporadic invasive ductal carcinomas. Four PTEN status groups were defined; complete loss (19/135, 14%), reduced copy number (19/135, 14%), normal (86/135, 64%) and complex (11/135, 8%). Whereas the PTEN complete loss status was significantly associated with estrogen receptor (ER) negativity (p=0.006) and in particular the basal‐like phenotype (p<0.0001), a reduced PTEN copy number was not associated with hormone receptor status or a particular breast cancer subtype. Overall, PI3K pathway alteration was suggested to be involved in 59% (79/134) of tumors as assessed by human epidermal growth factor receptor 2 overexpression, PIK3CA mutation or a complete loss of PTEN. A complex PTEN status was identified in a tumor subgroup which displayed a specific, complex DNA profile at the PTEN locus with a strikingly similar highly rearranged pan‐genomic profile. All of these tumors had relapsed and were associated with a poorer prognosis in the context of node negative disease (p=1.4 × 10^?13) thus may represent a tumor subgroup with a common molecular alteration which could be targeted to improve clinical outcome.     

Synthesis and characterization of polyurethane and poly(ether urethane) nanocapsules using a new technique of interfacial polycondensation combined to spontaneous emulsification

Polyurethane polymers and poly(ether urethane) copolymers were chosen as drug carriers for alpha-tocopherol. This active ingredient is widely used as a strong antioxidant in many medical and cosmetic applications, but is rapidly degraded, because of its light, heat and oxygen sensitivity. Polyurethane and poly(ether urethane)-based nanocapsules were synthesized by interfacial reaction between two monomers. Interfacial polycondensation combined with spontaneous emulsification is a new technique for nanoparticles formation. Nanocapsules were characterized by studying particle size (150-500 nm), pH, yield of encapsulation and morphologies. Polyurethanes (PUR) were obtained from the condensation of diisocyanate (isophorone diisocyanate: IPDI) and polyol: 1,2-ethanediol (EG), 1,4-butanediol (BD), 1,6-hexanediol (HD). Poly(ether urethane) copolymers were obtained by replacing diols by polyethylene glycol oligomers (PEG) M(w) 200, 300, 400 and 600. Molecular weights of di- and polyols have a considerable influence on nanocapsules characteristics cited above. The increase of molecular weight of polyols tends to increase the mean size of nanocapsules from (232+/-3)nm using EG to (615+/-39)nm using PEG 600, and led to the apparition of a population of agglomerate particles. We also noted that the yield of encapsulation increases with the increase of polyol length (from 85.6 to 92.2% w/w). Microscopic observations confirmed particle size analysis, but cannot predict the membrane structure owing the small size of the particles.