[Enzyme immunoassay of ampicillin in milk].

An indirect immunoassay for quantitative determination of ampicillin (range, 10-1000 ng/ml) in buffer or milk has been developed. Polyclonal antibodies were obtained against ampicillin conjugated with bovine serum albumin; the conjugate was synthesized by direct condensation using carbodiimide. The antibodies were specific for ampicillin and exhibited low cross-reactivity to other penicillins (azlocillin, 17%; penicillin G, 10%; piperacillin, 5%; and carbenicillin, 4%). Matrix effects were minimized by combining the use of a casein-supplemented buffer (content of casein, 1%) with sample dilution. The threshold of ampicillin detection in milk (diluted tenfold) was equal to 5.0 ng/ml (which corresponded to 50 ng/ml of the original sample).

[Morphological changes in rat liver in toxic drug-induced hepatitis and stimulation of repair processes]. / Morfologicheskie izmeniia v pecheni krys pri toksicheskom medikamentoznom gepatite i stimuliatsii reparativnykh protsessov.

Despite a large choice of drugs used for the treatment of chronic liver diseases, they often give only a temporary positive effect. In this study the effect of ursodeoxycholic acid on liver regeneration was investigated using the animal model of toxic hepatitis induced by anticonvulsive drug depackin, which is employed in infant neurology. The results of the study demonstrate stimulatory effect of ursodeoxycholic acid on regeneration process in animals' damaged liver, therefore its use may be recommended for the complex treatment of patients with toxic liver lesions.

[The suppression of the contractile activity of the cardiomyocytes by dermorphin in a heart culture of newborn rats]. / Podavlenie sokratitel'noi aktivnosti kardiomiotsitov dermorfinom v kul'ture serdtsa novorozhdennykh krysiat.

Opioid peptides exert ino- and chronotropic effects on the heart. Paraopioid dermorphine (Y-dA-F-G-Y-P-S) was earlier shown to act as negative inotropic agent in isolated frog's hearts. In this study, the same effect was investigated in cultured myocardiac cells of the newborn rats. Dermorphine (10(-4)-10(-9) M) dose-dependently attenuated the contraction amplitude with the latency of 5-10 min. The peak of the response appeared in 30-45 min after application of dermorphine. The mu-opiate-receptor antagonist naloxone (10(-5) g/ml) blocked this effect. Dermorphine seems to exert its negative inotropic action through the opiate receptors, presumably of the mu-subtype.

[Reparative regeneration of rat liver after treatment with bee venom]. / Reparativnaia regeneratsiia pecheni krys pri deistvii pchelinogo iada.

After 70% of the rat liver volume has been resected, certain stimulating effect of a single administration of bee venom (1 mg/kg) on hepatocyte proliferation is revealed. In 4 hours the amount of binuclear hepatocytes increases, and in 22-24 hours increases their mitotic activity. The effect of bee venom is explained as activation of the adenilate cyclase system by means of prostaglandins and adrenal hormones.

[Effect of chorionic gonadotropin on the content of prostaglandins (E + A) in pathologically altered liver tissue and blood of rats]. / Vliianie khorionicheskogo gonadotropina na soderzhanie prostaglandinov (E + A) v tkani patologicheski izmenennoi pecheni i v plazme krovi krys.

Twenty-four and 48 hours after injection of chorionic gonadotropin (CG) the content of prostaglandins E + A in the liver and blood plasma of white random-bred rats with chronic hepatitis increases (both after and without castration). This accounts for some aspects of the mechanism of the CG-induced stimulation of liver regeneration, which results in structural and functional normalization of the organ.

[Circadian periodicity of the processes of hepatocyte proliferation and hypertrophy in intact rats]. / Sutochnaia periodichnost' protsessov proliferatsii i gipertrofii gepatotsitov u intaktnykh krys.

In white noninbred rats hepatocytes have been studied morpho- and cytophotometrically. During evening-night time the volume of hepatocytes, their nuclei and cytoplasm increases, as do the amounts of benuclear and tetra- and octaploid cells. In the morning, on the background of maximal mitotic activity, the amount of the diploid cells increases, and the number of tetra- and octaploid hepatocytes, the volume of the nuclei and cytoplasm decreases.

[State of the microcirculation following total blood replacement with a model perfluorotributylamine-based blood substitute in rats]. / Sostoianie mikrotsirkuliatsii pri polnom zameshchenii krovi model'iu krovezamenitelia na osnove perftortributilamina u krys.

Microcirculation was studied in experiments on rats whose blood had been completely replaced by perfluorotributylamin emulsion. After blood replacement the microcirculatory channel was actively perfused with the blood substitute. It was shown that the emulsion circulation rate exceeded the initial rate of the blood flow, that high level of nutritive vessels perfusion was maintained and the physiological parameters of reactivity and functional motility of microvessels remained unchanged. It is suggested that under these circumstances there exist favourable conditions for transcapillary exchange. Active circulation of the blood substitute in the vascular channel lasted 1.5--2.5 h.

[Changes in lactate dehydrogenase activity and lactic and pyruvic acid concentration in the blood and tissues of animals following intravenous administration of perfluorotributylamine emulsions]. / Izmenenie aktivnosti laktatdegidrogenazy i soderzhaniia molochnoi i pirovinogradnoi kislot v krovi i tkaniakh zhivotnykh posle vnutrivennogo vvedeniia émul'sii perftortributilamina.

Activity of lactate dehydrogenase (LDH) and concentration of lactate and pyruvate were studied in rat and cat tissues after infusion of perfluorotributylamine emulsion. Administration of the emulsion caused an increase in content of lactate and pyruvate as well as LDH activation in the animal blood and tissues. Tissue hypoxia, responsible for stimulation of glycolytic pathway of carbohydrate metabolism, was apparently developed due to transfer of inadequate amount of oxygen by perfluorotributylamine.

[Hematopoietic study of rats in experiments with exchange blood replacement by an emulsion of perfluorotributylamine]. / Izuchenie krovetvoreniia u krys v opytakh s obmennym zameshcheniem krovi émul'siei perftortributilamina.

In experiments on nonanesthetized rats blood was substituted with perfluorotributyl emulsion (PFTBA). The mean volume of transfused PFTBA was 10 ml/100 g of body weight. During the period of blood replacement and the following 5 days the rats were kept in an atmosphere with increased oxygen content, and then they were placed under normal atmospheric conditions. The influence of PFTBA solution on hemopoiesis was studied in these experiments. A marked erythropoiesis activation in the bone marrow combined with expressed peripheral blood reticulocytosis was observed 6 days after the exchange blood substitution. Hemoglobin content decreased to 8.2 g% mature and immature white cell count rose; immature erythropoiesis cells were found: polychromatophilic erythro- and normoblasts (4.2% on the average). By the 13th day there was complete normalization of hemopoiesis which lasted 12 months without any significant deviations. Basing upon the results obtained it may be concluded that the PFTBA emulsion under study produces no negative effect on the animal hemopoiesis, and does not disturb the normal regulation process under conditions of the experiment conducted.