A 3-year study of prevention of postmenopausal bone loss: conjugated equine estrogens plus medroxyprogesterone acetate versus tibolone.

The aim of this study was to investigate the effects of tibolone in the prevention of postmenopausal bone loss over 3 years, and to compare these with the effects of sequential hormone replacement therapy. Forty early postmenopausal women were randomized to a 21-day regimen of conjugated equine estrogens (CEE, Premarin) plus sequential medroxyprogesterone acetate (MPA, Prodafem), or tibolone (Livial) daily. In total, 36 women completed 12 months and were considered for the intent-to-treat analysis, 34 completed 24 months and 23 completed 36 months. Main drop-out reasons were: lost to follow-up (n = 9) and minor side-effects (n = 4). Bone mineral density was measured at baseline and after 6, 12, 24 and 36 months, using dual-energy X-ray absorptiometry at the lumbar spine and the upper femur (neck, trochanter, total hip). In both groups, bone loss was prevented. Treatment with tibolone demonstrated significant increases in bone density at the spine (+4.6%; p < 0.01), at the total hip (+3.2%; p < 0.01) and at the trochanter (+4.5%; p < 0.01), whereas the CEE/MPA group showed a non-significant increase of bone mineral density at the lumbar spine (+2.6%) but no increases at the hip. Between-group differences in bone mineral density changes were significant (p < 0.05) for the total hip and the trochanter at 36 months. This increase of bone mineral density was not accompanied by changes in insulin-like growth factor-I (IGF-I) or insulin-like growth factor binding protein-3 (IGFBP-3) in either group. Osteocalcin, alkaline phosphatase and urinary ratios of hydroxyproline/creatinine and calcium/creatinine significantly decreased in both groups. In conclusion, sequential CEE/MPA prevented cortical and trabecular bone loss, with a transient increase of bone mineral density only during the first 6 months. Tibolone not only prevented cortical and trabecular bone loss, but further increased bone mineral density at the lumbar spine and at the hip throughout the 3 years of treatment, suggesting a sustained positive effect on bone mass

Measurement of single-diffractive dijet production in proton–proton collisions at √s=8Te with the CMS and TOTEM experiments

Measurements are presented of the single-diffractive dijet cross section and the diffractive cross section as a function of the proton fractional momentum loss ξ and the four-momentum transfer squared t. Both processes pp→pX and pp→Xp, i.e. with the proton scattering to either side of the interaction point, are measured, where X includes at least two jets; the results of the two processes are averaged. The analyses are based on data collected simultaneously with the CMS and TOTEM detectors at the LHC in proton–proton collisions at s=8Te during a dedicated run with β∗=90m at low instantaneous luminosity and correspond to an integrated luminosity of 37.5nb-1. The single-diffractive dijet cross section σjjpX, in the kinematic region ξ< 0.1 , 0.03<|t|<1Ge2, with at least two jets with transverse momentum pT>40Ge, and pseudorapidity | η| < 4.4 , is 21.7±0.9(stat)-3.3+3.0(syst)±0.9(lumi)nb. The ratio of the single-diffractive to inclusive dijet yields, normalised per unit of ξ, is presented as a function of x, the longitudinal momentum fraction of the proton carried by the struck parton. The ratio in the kinematic region defined above, for x values in the range - 2.9 ≤ log 10x≤ - 1.6 , is R=(σjjpX/Δξ)/σjj=0.025±0.001(stat)±0.003(syst), where σjjpX and σjj are the single-diffractive and inclusive dijet cross sections, respectively. The results are compared with predictions from models of diffractive and nondiffractive interactions. Monte Carlo predictions based on the HERA diffractive parton distribution functions agree well with the data when corrected for the effect of soft rescattering between the spectator partons. © 2020, CERN for the benefit of the CMS and TOTEM collaborations