Isoenzyme profile of lactate dehydrogenase in the cranial cervical sympathetic ganglion under normal conditions and during synaptic blockade.

The isoenzyme profile of lactate dehydrogenase in the cranial cervical sympathetic ganglion of rabbits was studied under normal conditions and during blockade of nicotinic cholinergic synapses. Under normal conditions this profile was presented by 5 isoforms of the enzyme (lactate dehydrogenases 1, 2, 3, 4, and 5). Activity of H-isoforms prevailed. Blockade was accompanied by heterotropic allosteric inhibition of lactate dehydrogenase isoforms. H- and M-isoforms underwent simultaneous changes. Activity of H-isoforms sharply decreased. However, the ratio between lactate dehydrogenases 1 and 2 during complete or partial blockade did not differ from that observed in experiments with the intact ganglion. M-isoforms (lactate dehydrogenases 4 and 5) disappeared during partial blockade. Activity of hybrid lactate dehydrogenase 3 significantly decreased and was undetected during partial and complete blockade, respectively. Our results indicate that enzyme activity and isoenzyme profile of lactate dehydrogenase are determined by function of nicotinic synapses.

[Transcutaneous transvenous occlusion of patent ductus arteriosus]. / Chreskozhnaia transvenoznaia okkliuziia otkrytogo arterialnogo protoka.

Transvenous closure is described of the patent ductus arteriosus with a conical device that consists of polyurethane foam mounted on a stainless steel flame. Since 1981, the procedure has been performed in 273 patients in Russia. Permanent complete ductus closure was achieved in 258 (95%) patients. In eight cases (3%), the occlusion was incomplete. Complications occurred in 10 patients (4%), seven of whom required emergency surgery. The new technique combines certain advantages of both alternative methods. The conical shape of the occlusion device is well suited for the anatomic structure of the ductus. The possibility of selecting the size of the device permits reduction in the rate of incomplete closure while still taking advantage of transvenous delivery to avoid entryside problems. In the initial 10 years of experience, the described technique proved effective, safe, and applicable in the vast majority of patients older than 2 years.

[The effect of weightlessness on amphibians. The ultimobranchial body]. / Vliianie nevesomosti na amfibii. Ul'timobrankhial'naia zheleza.

C-cells of Pleurodeles waltilii ultimobranchial bodies (ULT) were studied after a series of two-week spaceflight on the biosatellites. It was shown that under conditions of weightlessness the hypertrophy of ULT and calcitonin secretion activation occurred. Calcitonin accumulated into the ULT which resulted in metaplasia of the surrounding tissues, organ calcification and C-cells death. After landing, the regenerative processes which were not manifest in weightlessness occurred. They were similar to those of embryonic development of the organ.