M-H Lafage-Proust

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BACKGROUND Microgravity has been thought to induce osteoporosis because of reduced weight-bearing. However, up to now, few data have been available about its precise nature and timecourse. METHODS We measured bone mineral density (BMD) at the distal radius and tibia in 15 cosmonauts of the Russian MIR space station who sojourned in space either 1 (n=two),(More)
BACKGROUND Microgravity induces bone loss by mechanism(s) that remain largely unknown. METHODS We measured biochemical markers related to bone remodeling in two cosmonauts before, during, and after 21- and 180-day space flights, respectively. RESULTS During both flights, type I procollagen propeptide and bone alkaline phosphatase decreased as early as 8(More)
Quantitative microcomputed tomography using synchrotron radiation (SR microCT) was used to assess the effects of a sequential etidronate therapy on both three-dimensional (3D) microarchitecture and degree of mineralization of bone (DMB) in postmenopausal osteoporosis. Thirty-two iliac crest biopsy specimens were taken from 14 patients with osteoporosis(More)
Cadherins are a family of cell surface adhesion molecules that play an important role in tissue differentiation. A limited repertoire of cadherins has been identified in osteoblasts, and the role of these molecules in osteoblast function remains to be elucidated. We recently cloned an osteoblast-derived N-cadherin gene from a rat osteoblast complementary(More)
Long-term spaceflights induce bone loss as a result of profound modifications of bone remodeling, the modalities of which remain unknown in humans. We measured intact parathyroid hormone (PTH) and serum calcium; for bone formation, serum concentrations of bone alkaline phosphatase (BAP), intact osteocalcin (iBGP), and type 1 procollagen propeptide (PICP);(More)
The effects of antiresorptive drugs on bone loss remain unclear. Using three-dimensional microtomography, dual X-ray/densitometry, and histomorphometry, we evaluated tiludronate effects in the bone loss model of immobilization in tail-suspended rats after 7, 13, and 23 days. Seventy-eight 12-week-old Wistar male rats were assigned to 13 groups: 1 baseline(More)
OBJECTIVE The present study was conducted in order to describe the variations and circadian rhythm of biochemical markers of bone remodelling at baseline and after weight gain in patients with anorexia nervosa (AN). SUBJECTS We studied 9 women (mean age 21 years, range: 16-30) with established AN who remained amenorrhoeic during the study and with a low(More)
Spaceflight data obtained on bone cells, rodents, and humans are beginning to shed light on the importance of gravitational loading on the skeletal system. The space environment is a relevant model to explore the bone cell response to minimal strains. However, whether there is a direct effect of gravity on the cell rather than changes related to lack of(More)
The relationship between cell morphology and cell metabolism and the role of mechanical load in bone remodeling is well known. Mechanical stimulation induces changes in the shape of osteoblasts, probably mediated by reorganization of focal contacts. We studied the influence of gravity (Gz) variations occurring during parabolic flight on osteoblast focal(More)
Bone loss occurs in microgravity whereas an increase in bone mass is observed after skeletal loading. This tissue adaptation involves changes in osteoblastic proliferation and differentiation whose mechanisms remain largely unknown. In this context, we investigated the expression and the nuclear translocation of Egr-1 and NF-kappa B, in a simulated(More)