[Morphofunctional characteristics of the thyroid gland in intact and partially sympathectomized rats of different age groups]. / Morfofunktsional'naia kharakteristika shchitovidnoi zhelezy intaktnykh i chastichno desimpatizirovannykh krys raznykh vozrastnykh grupp.

The morphological and functional age-dependent changes have been studied in the thyroid gland of infantile (1-month-old), immature (2- and 3-month-old) and sexually mature (6-month-old) male rats. The decrease in thyroid functional activity with ageing was proved. Chemical sympathectomy (guanethidine at a dose of 15 mg/kg intramuscularly for 14 days after birth) was accompanied not only by morphological reconstruction of the thyroid tissue, but also (especially in 1-month-old rats) by a delay in transport-organic phase of iodine metabolism and a decline in thyroid hormone serum level. Later on, the compensatory hormonogenesis reinforcement occurs as a result of partial adrenergic innervation recovery.

[Radionuclide methods of determining digoxin levels]. / Radionuklidnye metody opredeleniia kontsentratsii digoksina.

The digoxin level in the blood was determined in 92 patients with blood circulatory insufficiency using radioimmunoassays (Sea Ire-Sorin kits) and radionuclide (86 Rb) methods. Pharmacokinetics of digoxin was evaluated on the basis of a two-compartmental mathematical model (by J. Y. Wagner). Direct correlation between the value of a maintenance dose and digoxin concentration in the blood was established. Digoxin values in the blood determined by the radionuclide method, were somewhat higher than the indices of the radioimmunological method. According to this method digoxin therapeutic concentrations in the blood were: 0.4-2.8 ng/ml; according to the radionuclide method 0.6-4.8 ng/ml. Symptoms of digoxin intoxication (overdosage) in rising its concentration in the blood up to 1.1-3.3 ng/ml by the radioimmunoassay and up to 2.2-6.1 ng/ml by the radionuclide method were recorded. It can be accounted for by the fact that bigger values of digoxin active metabolites are determined by the radionuclide method, whereas the radioimmunoassay is more specific to digoxin. Pharmacokinetic parameters (distribution volume, digoxin clearance, the period of semi-elimination) calculated by two methods, brought about the same results. Regularities of the changes of digoxin pharmacokinetics in patients with disturbed renal function are analysed.