Neurobehavioral and biochemical response to manganese and selenium exposure in rats.

Aiming to extend previous findings, male Wistar rats were treated per os for 13 weeks with manganese chloride in two doses: 300 mg/kg body weight (group I) and 20 mg/kg b.w. (II), the former was associated (III) with a microdose (1 ppm) of natrium selenite. The findings show an impairment of active avoidance learning in group III, a decrease of swimming performance and histological lesions in several brain areas (both especially in group III), changes of the aggressive behavior and decreases in the brain tissue of superoxide dismutase activity (I & II) and of lipid peroxidation (in all groups).

Erythropoietin binding to the red cell membranes.

Some characteristics of Epo binding to the red cell membranes were investigated in a system in which the hormone was added to a suspension of cells in a mixture of normal serum phosphate buffered saline (1:7 (V/V)), testing the unbound Epo. Epo binding shows a gradual decrease during the maturation of red cells (0.15 U/ml packed erythrocytes, 0.285 U/ml reticulocytes and 0.375 U/ml erythroblasts from a total of 1.4 U/ml). The binding is also time- and pH-dependent. The amounts of Epo bound within 60 min are independent of temperature, but after 120 min a dissociation of the hormone-receptor complex occurred at 23 and 37 degrees; at 4 degrees C the binding continue, although at a very low rate. RBC membranes bound the hormone at pH 7.8-8 and release it at pH 6.5. The "in vivo" stimulation of beta receptors with isoproterenol increases the erythropoietic response caused by Epo, suggesting a possible relation with the adenylcyclase system.

Undersea psychophysiologic reactions of human organism.

The determinations carried out on 12 divers during the immersion into the sea to a depth between 7 and 29 m, as well as on controls in immersions at 4 m revealed a significant prolongation of the visual reaction time and a marked tachycardia. The changes were more marked at great depths and if exercise was superimposed over hyperbaric stress. A rise in the urinary excretion of 17-HOCS and vanillylmandelic acid and an impairment of the manual dexterity were also found during immersions. The results stress the importance of divers' monitoring during their underwater activity and the necessity of improving their physical training.

The influence of moderate hyperbaric environment on some nervous functions and on the sympatho-adrenal and adreno-cortical activity in man.

Thirteen healthy males were repeatedly studied during the exposure to a moderate hyperbaric environment of 4--6, 7 and 9 ATA, in a hyperbaric chamber and partly during immersion in sea water (3.5--4 ATA). The maximal duration of the exposure was 35 min and that of decompression 90 min. As compared to the dynamics of the change found in controls, under hyperbaric conditions a significant prolongation of the visual reaction time (especially during sea dives), and an impairment of the mental performance in an arithemetical calculation test were found. There occurs an increase of the excretion in urine of cortisol, epinephrine and vanillylmandelic acid, especially after immersion in sea.

Action of some pituitary hormones on the work capacity in rats.

FSH (50 mu/rat X 12 days), ICSH (in the same dosis) and gonadotropinum sericum (20 U/rat X 13 days) have a prevailing inhibitory influence on the motor activity in untrained or/and trained rats. TSH raises the motor performance but significantly only in great doses (1.5 IU/100g body weight X 13 days). GH (0.1 and 0.5 mg/rat X 16 days) reduces the favourable effects of moderate training on the run performance. A part of these results could be explained by the studied biochemical changes.