[Characteristics of proteinase digestive function in invertebrates--inhabitants of cold seas].

Digestive proteinases of various taxa of invertebrates of the Northern seas have been studied: crustaceans Paralithodes camtchaticus, Pandalus borealis; molluscs Chlamys islandicus, Buccinum undatum, Serripes groenlandicus, and echinoderms Strongylocentrotus droebachiensis, Cucumaria frondosa, Asterias rubens, and Grossaster papposus. The presence of two proteolytic activity peaks in the acid (pH 2.5-3.5) and low alkaline zones (pH 7.5-8.5) and a similar proteinase spectrum have been revealed in digestive organs of the studied animals. The proteolytic activity in digestive organs of the Barents Sea invertebrates exceeds significantly that of terrestrial homoiothermal animals, which seems to be an extensive compensation for poor differentiation of the digestive system and for low substrate specificity of the enzymes as well as for cold conditions of the habitat. The principal qualitative difference between vertebrates and invertebrates consists in that the latter have no pepsin activity, but do have the cathepsin activity that is absent in vertebrate digestive organs. Contribution to the acid proteolysis is made by lysosomal cathepsins, rather than by pepsins. Activity in the alkaline and neutral pH zones is provided by serine proteinases. In digestive cavities of invertebrates, hydrolysis of proteins and mechanical processing of food occur only in the low alkaline zone, whereas acid proteolysis has intracellular lysosomal localization.

[Pharmacokinetic characteristics of trimecaine compared to lidocaine in myocardial infarct patients]. / Farmakokineticheskie kharakteristiki trimekaina v sravnenii s lidokainom u bol'nykh infarktom miokarda.

The authors studied pharmacokinetics of trimecain and lidocain in 10 and 15 patients with myocardial infarction, respectively, after a single intravenous jet injection in the dose of 80 mg. The groups were comparable as to age, mass and surface of the body. In all patients the dependence of trimecain and lidocain concentrations on time was biexponential. Average individual values of distribution volumes in stationary condition and in the stage of elimination, clearance and half-life differed but insignificantly for trimecain and lidocain. The results obtained justify the conclusion that trimecain and lidocain are identical from the pharmacokinetic point of view.

[Comparative clinical study of trimecaine and lidocaine as anti-arrhythmia agents in myocardial infarct]. / Sravnitel'noe klinicheskoe izuchenie trimekaina i lidokaina v kachestve antiaritmicheskikh sredstv u bol'nykh infarktom miokarda.

The article discusses the comparative antiarrhythmic effectiveness of trimecaine and lidocaine in patients with acute myocardial infarction in the first 24 hours of the disease. The 45 patients included in the study were separated into 3 groups: the 1st (control) group consisted of 15 patients with acute myocardial infarction who were not given antiarrhythmic or arrhythmogenic agents; the 2nd group was formed of 15 patients who from the time of admission were given trimecaine by intravenous drip at a rate of 2 mg/min for purposes of prevention after preliminary jet-injection of 80 mg of the drug; the 3rd group consisted of 15 patients given lidocaine by the same schedule. An antiarrhythmic effect was noted in 60% of group 2 patients and in 87% of group 3 patients. No antiarrhythmic effect was produced in 40% of patients treated with trimecaine and in 13% of those given lidocaine.

[Lidocaine pharmacokinetics when administered intramuscularly]. / Farmakokinetika lidokaina pri vnutrimyshechnom vvedenii.

The pharmacokinetics of lidocain injected intramuscularly in doses of 300-600 mg was studied and compared to that on its intravenous administration in a dose of 80 mg in the same patients with acute myocardial infarction. When injected intramuscularly the drug rapidly and safely reached the systemic circulation. The relationship between the lidocain plasma concentration and time could be depicted adequately by an open one-compartmental model to determine the parameters of the model. The maximum concentration (2.34 micrograms/kg for a dose of 400 mg) was attained 44 min after the injection. The half-life was 101 min, and the total clearance 0.67 l/min. Analysis of the model curves concentration--time for the doses 400 and 600 mg showed that in the former case the effective concentration (2 micrograms/kg or more) was maintained for 1 h, whereas in the latter one for 2.3 h.

[Lidocaine pharmacokinetics and substantiation of the new method of its administration in myocardial infarct]. / Farmakokinetika lidokaina i obosnovanie novogo rezhima ego vvedeniia bol'nym ostrym infarktom miokarda.

Lidocain pharmacokinetics was studied in 12 patients with acute myocardial infarction (males and females from 40 to 90 years of age with obvious disorders of hepatic and kidney function or severe hemodynamic disorders). In ten of them the main pharmacokinetic parameters were determined; the average value of lidocain clearance was 0.45 1/min. The optimum rate of continuous drip infusion was calculated (1.35 mg/min). It is shown that the existing method of lidocain administration by the "initial dose + infusion" schedule is unsatisfactory from the pharmacokinetic standpoint. Recommendations are given for the choice of the optimum concentrations of lidocain solution used in different rates of continuous infusion.