[Legal and forensic medical problems of postmortem donation]. / Pravovye i sudebno-meditsinskie problemy posmertnogo donorstva.

The article is devoted to legal and forensic medical problems of postmortem donation. The substantive provisions of postmortem donation, as well as normative legal documents regulating the processes of organs harvesting from deceased persons for subsequent transplantation and governing the work of transplantologists and forensic medical experts have been considered. The practical examples illustrating the essence and nature of the problem of postmortem forensic medical expertise of persons with absent organs has been given and the importance of the participation of a forensic medical expert involved in the decision-making process on possibility (or impossibility) of the corpse's organs and tissues explantation without prejudice to the further expert examination has been emphasized. The authors pay particular attention to the inadequacy of the legal framework, including the lack of a clear understanding of the legal status of the person holding the position of forensic medical expert, who provides an expert opinion on the organs' explantation.

MicroRNA miR-133a-3p Facilitates Adrenergic Proarrhythmic Ectopy in Rat Pulmonary Vein Myocardium by Increasing cAMP Content.

Cardiac-specific microRNA miR-133a-3p modulates adrenergic signaling. Adrenergic receptors and their intracellular pathways are the key players in proarrhythmic ectopy derived from the myocardial sleeves of the pulmonary veins. We studied the effect of miR-133a-3p on ectopy induced by norepinephrine in myocardial tissue of rat pulmonary veins. Using microelectrode technique, we revealed facilitation of proarrhythmic pattern of spontaneous bursts of action potentials induced by norepinephrine in tissue preparations of the pulmonary veins isolated from rats in 24 h after injection of a transfection mixture containing miR-133a-3p (1 mg/kg) in vivo. According to ELISA data, the cAMP level in the pulmonary vein myocardium of rats receiving miR-133a-3p was 2-fold higher than in control animals. Bioinformatic analysis showed that mRNA of protein phosphatases and some phosphodiesterases are most probable targets of miR-133a-3p. The proarrhythmic effect of miR-133a-3p can be related to inhibition of the expression of phosphodiesterases accompanied by cAMP accumulation and increased intracellular ß-adrenergic signaling.

Role of Muscarinic M1, M2, and M3 Receptors in the Regulation of Electrical Activity of Myocardial Tissue of Caval Veins during the Early Postnatal Ontogeny.

We studied the influence of blockers of muscarinic M1, M2, and M3 receptors on the effect of acetylcholine in the myocardial tissue of caval veins in rats at the early stage of ontogeny. The experiments were performed on isolated preparations of the right superior vena cava working under their own rhythm. Action potentials were recorded using the standard microelectrode technique. Acetylcholine (1 µM) suppressed automatic activity in the superior vena cava myocardium. Preliminary perfusion of the preparation with non-selective blocker atropine (1 µM) completely abolished the effect of acetylcholine, treatment with M2 receptor blocker AQ-RA 741 (1 µM) led to partial suppression of the effect of acetylcholine. Blockers of M1 and M3 receptors pirenzepine (1 µM) and 4DAMP (0.1 µM) did not suppress the effect of acetylcholine. Thus, the effect of acetylcholine is predominantly realized via M2 receptors, but M3 receptors can also partially mediate its effect in the superior vena cava myocardium in rats at the early stages of ontogeny.

Extracellular NAD+ Suppresses Adrenergic Effects in the Atrial Myocardium of Rats during the Early Postnatal Ontogeny.

The effects of sympathetic cotransmitter NAD+ (10 µM) on bioelectric activity of the heart under conditions of adrenergic stimulation were studied on isolated spontaneously contracting preparations (without stimulation) of the right atrium from 2-7-day-old rats. Action potentials were recorded in the working myocardium using standard microelectrode technique. Perfusion of the right atrium with norepinephrine solution (1 µM) altered the configuration and significantly lengthened the action potentials. NAD + against the background of norepinephrine stimulation significantly decreased the duration of action potentials, in particular, at 25% repolarization. The effect of purine compounds NAD + , ATP, and adenosine on bioelectrical activity of the heart of newborn rats was studied under basal conditions (without norepinephrine stimulation). The effect of NAD + against the background of adrenergic stimulation was more pronounced than under basal conditions and was probably determined by suppression of ICaL, which can be the main mechanism of NAD + action on rat heart.

ß-Adrenergic stimulation induces pro-arrhythmic activity in the caval vein myocardial tissue.

Electrical activity of the right superior vena cava (SVC) is considered as a source of the atrial fibrillation. We have shown that bioelectrical properties of the SVC myocardium differ from those of the working atrial myocardium. Electrically evoked action potential duration in SVC is significantly shorter, the resting membrane potential in both stimulated and quiescent SVC preparations is significantly more positive than in atria. Activation of ß-adrenoreceptors in SVC myocardium leads to a series of action potentials, and this process depends on protein kinase A. Probably, ß-adrenergic stimulation enhances SVC arrhythmogenesis in vivo.

Chromosomal Aberrations As a Biological Phenomenon in Human Embryonic Development.

Frequent chromosomal abnormalities are a distinctive feature of early embryonic development in mammals, especially humans. Aneuploidy is considered as a contributing factor to failed embryo implantation and spontaneous abortions. In the case of chromosomal mosaicism, its effect on the potency of embryos to normally develop has not been sufficiently studied. Although, a significant percentage of chromosomal defects in early human embryos are currently believed to be associated with the features of clinical and laboratory protocols, in this review, we focus on the biological mechanisms associated with chromosomal abnormalities. In particular, we address the main events in oocyte meiosis that affects not only the genetic status of an unfertilized oocyte, but also further embryo viability, and analyze the features of first cleavage divisions and the causes of frequent chromosomal errors in early embryonic development. In addition, we discuss current data on self-correction of the chromosomal status in early embryos.