Asymmetric ABC-triblock copolymer membranes induce a directed insertion of membrane proteins.

Asymmetric molecules and materials provide an important basis for the organization and function of biological systems. It is well known that, for example, the inner and outer leaflets of biological membranes are strictly asymmetric with respect to lipid composition and distribution. This plays a crucial role for many membrane-related processes like carrier-mediated transport or insertion and orientation of integral membrane proteins.

Vesicles with asymmetric membranes from amphiphilic ABC triblock copolymers.

A new amphiphilic ABC triblock copolymer (poly(ethylene oxide)-poly(dimethyl siloxane)-poly(methyl oxazoline)) has been synthesized and demonstrated to form vesicular structures with asymmetric membranes in aqueous media.

Mechanisms and significance of QRS macrovoltage in the absence of cardiac hypertrophy.

The electric stimulation of the lateral ventricular walls carried out in experiments on dog heart (open-thorax), as well as the analysis of the clinical, radiological and electrocardiographic data recorded in 462 cases with QRS macrovoltage led to the following conclusions: a) in 22% of the cases (hospital cardiologic examinations) this anomaly cannot be accounted for either by age, blood pressure or cardiac hypertrophy; b) a temporarily perturbed development of the ventricular depolarization, i.e. a "jerky" depolarization, not stagnant enough to produce an intraventricular block, may generate great negativity and positivity myocardial masses responsible for the appearance of large dipoles, namely of the increased QRS voltage; c) the coincident ischemia and macrovoltage of the QRS major wave, as well as the subsequent evolution of incipient CHD in a series of patients point to the hypothesis according to which the regional myocardial ischemia may induce a QRS macrovoltage by means of the above mechanism.