Dose-dependent analysis of acute medical effects of mixed neutron-gamma radiation from selected severe 235U or 239Pu criticality accidents in USSR, United States, and Argentina.

Eight of the most severe cases of acute radiation disease (ARS) known to have occurred in humans (as the result of criticality accidents) had survival times less than 120 h (herein defined as "early death"). These accidents were analyzed and are discussed with respect to the specific accident scenarios and the resulting accident-specific, mixed neutron-gamma radiation clinical dose distributions. This analysis concludes that the cardiovascular system appears to be the most critical organ system failure for causing "early death" following approximate total body, mixed gamma-neutron radiation doses greater than 40-50 Gy.

[Cardiac effects of fenibut in development of experimental chronic renal insufficiency].

The effect of fenibut on the mechanical activity of myocardium was studied in vitro and in vivo in rats with experimental chronic renal insufficiency (CRI) in a regime of physiologically alternating load simulating the intact heart function. The administration of fenibut (10 mg/kg) in rats after nephrectomy prevents the development of myocardial hyperfunction (characteristic of the animals with CRI in stage 1). In in vitro experiments on isolated myocardium fenibut also decreased the myocardial hyperfunction and reduced contractility to a control level, which was accompanied by accelerated relaxation in all finite systolic lengths.

[The effect of He-Ne laser radiation on myocardium mechanical activity in rats].

In isolated papillary muscles, a 5-minute irradiation with the He-Ne-laser Shuttle-1 enhances the maximal strength of isometric contraction and acceleration of relaxation. In physiological mode of mechanical loads, the irradiation with the laser red light enhances the myocardium contractability at all final systolic lengths with simultaneous enhancement of the isometric relaxation velocity at great systolic lengths and a deceleration of the relaxation at lesser lengths. Under the He-Ne-laser effect, restoration of rhythm-inotropic relationships occurred in the myocardium.

[Effects of parathyroid hormone and parathyroid hypertensive factor on myocardial mechanical properties in normotensive rats].

After a 10-minute incubation, both the parathyroid hypertensive factor (PHF) and parathyroid hormone (PTH) reduced myocardial contractility and accelerated myocardial relaxation. Effects of the PTH and PHF on myocardial inotropic characteristics were of opposite directions.