RESUMEN
The extent and structure of the adsorbed layer of gelatin onto colloidal particles is measured using dynamic light scattering, small-angle neutron scattering, and dilution viscometry. Adsorption isotherms are measured using solution depletion of fluorescein-5-isothiocyanate tagged gelatin. The results show that the adsorbed gelatin layer at saturation on acrylic-based latex (pH 6.5, 0.01 M sodium acetate) has approximately twice the average density of the free gelatin in solution, while for the adsorption onto polystyrene latex (pH 8.7, deionized water), it has nearly the same average density. The energetics of gelatin affinity is calculated from the temperature dependence of the adsorption equilibrium constant. It was found that the enthalpy of adsorption of a net negatively charged gelatin onto a negatively charged surface is favorable. An additional, favorable entropy of adsorption is measured for the polystyrene latex, for which hydrophobic interactions are important. Selective, competitive adsorption of nonionic and anionic surfactants confirms the specific source of the adsorption interactions. Copyright 1998 Academic Press.
RESUMEN
The authors followed for at least two years 483 patients (430 coronary prone patients and 53 with proved coronary heart disease), to determine whether physical training could decrease coronary risk factors and improve exercise tolerance in the trained group as compared with the conventionally treated group (way of life, diet, drugs). There was no significant difference among the two groups for blood lipid profile, blood pressure (at rest and during exercise), functional capacity and mortality. In the authors' opinion this could be explained by the inadequate training program (45 minutes twice a week) and by a possible overlapping of the groups.
