[Heart arrhythmias and conduction disorders in patients with acromegaly: the role of cardiac magnetic resonance imaging].

Unlabelled: Cardiovascular complications including arrhythmias and cardiac conduction disorders are one of the main reasons of high mortality rate in acromegaly, while they have not been well explored.

Aim: To estimate arrhythmias frequency in acromegaly, identify risk factors leading to the development of arrhythmia and cardiac conduction disorder, to determine the role of cardiac MRI in detecting structural and functional changes.

Materials And Methods: A single-center prospective cohort study, which included 461 patients (151 men and 310 women) with acromegaly, was conducted.

[Surface Microdeformations and Regulation of Cell Movements in Xenopus Development].

The velocities and directions of movements of individual outer ectodermal cells of Xenopus embryos in the course of normal development from the blastula to the early tail-bud stage, as well as after mechanical relaxation in the early gastrula, were measured. An alternation of the periods of directed movements of large cell masses and local cell wanderings was detected. In both cases, the trajectories of individual cells consisted primarily of orthogonal segments.

[Mechano-geometric generative rules of morphogenesis].

The ideographical approach aimed at detecting specific causative relationships within the process of development prevails in modern embryology. The present work considers the possibilities of using the nomothetic approach aimed at putting forward nonspecific general laws based on the general scientific theory of self-organization and can be formulated in morphomechanical terms based on feedback links between passive and active mechanical stress. The perspectives of this approach and the involvement of genetic factors in the regulation of feedback links are discussed.

[Statistical study of rapid mechanodependent cell movements in deformed explants of African clawed frog Xenopus laevis embryonic tissues].

Computer analysis of artificially deformed (stretched or compressed) double explants (sandwiches) of the blastocoel roof (BRs) and suprablastoporal region (SBRs) of African clawed frog Xenopus laevis early gastrula has been performed using frames of time-lapse microfilming. During the first 14 min after cutting off, the velocities and displacement angles of several hundreds of cells relative to one another, as well as to fixed points and the extension axis, were measured in the control and deformed samples. It has been found that the deformation of samples leads to a rapid reorientation of large cell masses and increase in the velocities of movements along the extension axes or perpendicularly to the compression axes.

[Passive and active reactions of embryonic tissues to the action of dosed mechanical forces].

With the help of a suction manometric device, the relation between the deformation of Xenonus laevis embryo at the gastrula and neurula stages and the value of the applied force has been studied. Stiffness modules of embryonic tissues were in the order of several dozens of Pascal and they were inversely proportional during deformation from 40 to 20%. At the gastrula stage, a uniform or an increasing rate of expansion of the embryo body in the suction capillary with the diameter of approximately half that of the embryo was observed for 30 min after the action of the suction forces.