Gail model breast cancer risk components are poor predictors of risk perception and screening behavior.

The Gail model is being used increasingly to determine individual breast cancer risk and to tailor preventive health recommendations accordingly. Although widely known to the medical and biostatistical communities, the risk factors included in the model may not be salient to the women to whom the model is being applied. This study explored the relationship of the individual Gail model risk factors to perceived risk of breast cancer and prior breast cancer screening among women with a family history of breast cancer. Data from baseline interviews with 969 women found a striking disparity between the objective risk factors included in the model and the accuracy of perceived risk and screening behaviors of this population, particularly among women over the age of 50 years. Risk perception accuracy was unrelated to all of the Gail model risk factors for all age groups. Reported mammography adherence was only associated with having had a breast biopsy in both age groups. Breast self examination (BSE) practice was independent of all measured factors for both age groups. These findings support the need for further research to identify additional determinants of risk perception and motivators of screening behavior.

31P NMR quantitation of the displacement of equilibria of arginine, creatine, pyruvate, and 3-P-glycerate kinase reactions by substitution of sulfur for oxygen in the beta phosphate of ATP.

31P NMR measurements have been found to be a convenient means for simultaneously measuring the concentrations of several species in the equilibrium mixtures of the reactions catalyzed by arginine kinase and creatine kinase. MgATP + X in equilibrium MgADP + XP where X = arginine or creatine and XP = P-arginine or P-creatine. The free energy of phosphorylaton of various metabolites by adenosine 5'-O-(2-thiotriphosphate) at pH 8.0 and 30 degrees C is more exergonic than the corresponding phosphorylations by ATP by about 2.5 kcal/mol, resulting in a displacement of the equilibrium toward the nucleoside diphosphates by a factor of approximately 60. Since this factor does not depend on the nature of the metabolite, the equilibrium constants of thionucleotide reactions may be used to determined the equilibrium constants of corresponding oxynucleotide reactions which lie too far toward ATP. The equilibrium constants of the oxynucleotide reactions catalyzed by pyruvate kinase and 3-P-glycerate kinase calculated by this method from the experimentally determined equilibrium constants of the corresponding thionucleotide reactions are 3.1 x 10(-4) and 2.9 x 10(-4), respectively, under the experimental conditions used. The equilibrium constants and degree of stereoselectivity of the arginine kinase reaction are altered when Ca2+ replaces Mg2+ as the activating metal ion.