[The ultrastructural characteristics of liposome interaction with bacterial cells]. / Ul'trastrukturnye osobennosti vzaimodeistviia liposom s bakterial'nymi kletkami.

The electron-microscopic study of the mechanism of interaction between liposomes of different sizes and gram-positive and gram-negative microorganisms has been made. As shown in this study, gram-positive microorganisms do not come into direct contact with liposomes. gram-negative microorganisms actively contact with small-size (100-200 nm) and medium-size (200-300 nm) liposomes. Large-size liposomes (greater than bacterial cells) "ingest" microorganisms themselves, thus facilitating the development of destructive changes in them.

[Purification and properties of Bordetella pertussis toxin]. / Ochistka i nekotorye svoistva kokliushnogo toksina Bordetella pertussis.

The modified method for the isolation and purification of B. pertussis toxin has been proposed. Chromatography with the use of hydroxylapatite and lentil lectin--Sepharose 4B has permitted the isolation of the preparation purified 600 times. Its molecular weight is about 90,000. The preparation has been found to possess leukocytosis-stimulating, histamine-sensitising and hemagglutinating activity. Electrophoretic analysis has revealed that the isolated substance consists of four subunits with molecular weights 28,400, 24,300, 21,800 and 15,200. This substance has proved to be capable of hydrolyzing NAD+, as well as of suppressing the GTPase activity of transducin, which is indicative of the covalent modification (ADP-ribosylyzing) of GTP-binding protein under the action of B. pertussis toxin. Two methods for the isolation of B. pertussis toxin (from liquid and solid growth media), as well as the isolation of the toxin from different B. pertussis strains, are evaluated.

[Effect of extracorporeal sorption on the content of free intracellular calcium of the leukocytes in atopic bronchial asthma]. / Issledovanie vliianiia ékstrakorporal'noi sorbtsii na soderzhanie svobodnogo vnutrikletochnogo kal'tsiia v leikotsitakh pri atopicheskoi bronkhial'noi astme.

Antigen-IgE-antibody interaction on the cell surface in an allergic reaction increases methylation of phospholipids of a cell membrane making it permeable for Ca2+ ions. Therefore of interest is a study of free intracellular Ca2+ concentration from a view-point of development of atopic bronchial asthma and the use of extracorporal methods of its therapy permitting the elimination of IgE-antibodies from the blood flow. The level of intracellular Ca2+ in the leukocytes of patients with atopic bronchial asthma was studied. It has been shown that 1. the fraction of leukocytes with a higher level of intracellular Ca2+ in patients with atopic bronchial asthma was increased as compared to healthy donors; 2. extracorporal sorption results in a decrease in the number of leukocytes with high Ca concentration.

[The effects of influence of electromagnetic irradiation of millimeter wavelength on background impulse activity of supraoptic nucleus' neurons of rats' hypothalamus].

In conditions of acute experiment on white rats anaesthetized by Nembutal (40 mg/kg, intraperitoneally), the registration and analysis of background impulse activity of the supraoptic nucleus neurons of rats' hypothalamus in norm and after electromagnetic irradiation of millimeter wavelength on organism, were carried out. Distributions of neurons by the degree of rhythm regularity, the character of types of dynamics of the following impulse flows, the modality of histograms of interspike intervals, the average discharge frequency, the coefficient of interspike intervals variation, were found out. Changes of the background impulse activity which were related mainly to the changes of the inner structure of registered impulse flows, were revealed. Significant shifts were generally observed in the character of dynamics of neuronal current flows and degree of regularity of the impulse activity. Statistically significant changes of the average frequency of discharges of different frequency range neurons' populations were revealed.

[Comparative analysis of spontaneous unit activity of the cerebellum fastigial nucleus' neurons in different periods of vibration influence].

In conditions of acute experiment on white rats anaesthetized with Nembutal (40 mg/kg, interperitonially) recording and analysis of spontaneous impulse activity of the fastigial nucleus' neurons in norm and after 5, 10 and 15 days of vibration influence on the organism were carried out. Distribution of the neurons was evaluated by the dynamics of neuronal current flow and the modality of the interspike interval hystograms, as well as the statistical parameters: the average discharge frequency and the coefficient of the interspike interval variation. It is shown that more significant changes in neuronal activity of fastigial nucleus cells are formed during the first 10 days of vibration influence. On the 15th day, there was a tendency towards return to control levels of the parameters under study.

[Effects of hypoxia on phosphoinositide turnover and adenylate cyclase system in cultured endothelial cells]. / Effekty gipoksii na fosfoinozitidnyi obmen i adenilattsiklaznuiu sistemu v kul'tiviruemykh éndotelial'nykh kletkakh.

By studying the effects of oxygen deficiency upon signal-transducing system it has been shown that in long hypobaric hypoxia activates PI-turnover in cultured human endothelial cells. The sensitivity of cells to histamine was decreased as well as the adenylate cyclase activity in membranes of this cells. The amount of beta-adrenoreceptors was not influenced significantly. Incubation of endothelial cells with histamine (10(-5) M) and phorbol ester (10(-9) M) = activator of protein kinase C within 1-2 h resulted in desensitization of cellular responses which can be seen not only as a disappearance of histamine-induced activation of PI-turnover but also as a decrease of beta-adrenoreceptor amount and adenylate cyclase activity. It seems that hypoxia may change the action of Ca-mobilizing hormones on PI-turnover and suppress adenylate cyclase in human endothelial cells. However the effects of hypoxia on signal-transducing systems in this cells are developed slower than those of Ca-mobilizing hormones.

[The beta-adrenergic receptor and adenylate cyclase of rat reticulocytes as a test system for screening pharmacologic preparations]. / Beta-adrenergicheskii retseptor i adenilattsiklaza retikulotsitov krysy kak test-sistema dlia skrininga farmakologicheskikh preparatov.

The effect of cardio- and neurotropic drugs was studied on beta 2-adrenergic receptors and coupled adenylate cyclase (AC) from rat reticulocytes. Trifluperazine, chlorpromazine, levomepromazine, metaphenazine, haloperidol, (+) and (-) isomers of butaclamol, as well as imipramine, vinblastine and verapamil, at a concentration of 10(-4) M failed to influence AC stimulation by isoproterenol. Thioproperazine and trifluperidol inhibited isoproterenol-stimulated AC with Ki = 4.0.10(-5) M and Ki = 4.5.10(-5) M, respectively. This inhibitory effect was due to the direct action of thioproperazine and trifluperidol on the beta-adrenergic receptors, since this drugs displace the receptor-bound (3H) dihydroalprenolol with Ki = 5.10(-6) M and 9.10(-6) M, respectively. The results obtained suggest that adrenolytic effect of trifluperidol and thioproperazine might play a significant role in their side effects.

[Identification and characteristics of the beta-adrenergic receptors in the membranes of cultured endothelial cells of the human pulmonary artery]. / Identifikatsiia i kharakteristika beta-adrenergicheskikh retseptorov v membranakh kul'tiviruemykh kletok éndoteliia legochnoi arterii cheloveka.

The properties of beta-adrenoreceptors (beta-AR) have been studied in endothelial cells from the human pulmonary artery (EPA) and umbilical vein (EUV). [125I] Iodosyanopindolol binding assay revealed the amount of 22 and 12 fmol/10(6) cells as well as Kd = 92 and 52 pM for EPA and EUV, respectively. Adrenergic agonists increased the cAMP levels in EPA in the order of potency characteristic for beta 2-AR: isoproterenol greater than epinephrine greater than norepinephrine. Basing on the results obtained in the present study and the literature data a conclusion is made that the properties of beta-AR in vascular endothelial cells do not practically depend on their localization, suggesting universality of their function within the vascular system.

[Biochemical features of platelet alpha2-adrenergic receptors and their connection with an increase in concentration of intracellular Ca2+]. / Biokhimicheskie osobennosti alpha2-adrenoretseptorov trombotsitov i ikh sviaz' s povysheniem kontsentratsii vnutrikletochnogo Ca2+.

Epinephrine (E) and norepinephrine (NE) alone did not increase free intracellular Ca2+ ([Ca2+]i) in human platelets loaded with Quin-2 or Fura-2; however, they did potentiate the effects of vasopressin (VP), serotonin (S) and platelet activating factor (PAF). The synergism in [Ca2+]i increase was also obtained in the presence of VP together with PAF, S with PAF as well as VP with S. The effect of E or NE was blocked by yohimbine and phentolamine. Prazosin was less effective, while propranolol had no effect at all. Clonidine did not potentiate the effects of VP, S or PAF on [Ca2+]i; however, it did block the potentiation induced by E or NE. E potentiated the VP-induced 45Ca2+ uptake as well as VP-stimulated inositol 1,4,5-trisphosphate (IP3) formation. E alone did not change significantly the level of IP3 in platelets, nor did it influence the cyclic AMP level. The experimental results suggest that both Ca2+ influx and polyphosphoinositide breakdown underlie the mechanism of potentiation.

[Reconstitution of sensitivity of solubilized rabbit heart adenylate cyclase to hormones and guanyl nucleotides]. / Vosstanovlenie chuvstvital'nosti soliubilizirovannoi adenilattsiklazy serdtsa krolika k gormonam i guanilovym nukleotidam.

Solubilization of adenylate cyclase by lubrol PX results in a loss of the enzyme sensitivity to hormones; however, the enzyme retains its ability to be activated by guanyl nucleotides and NaF. Lubrol WX devoids adenylate cyclase of its sensitivity to hormones and NaF. Solubilization causes a shift in the pH optimum of the enzyme towards neutral values of pH and significantly decreases the thermal stability of adenylate cyclase. The replacement of lubrol PX from the solubilized preparation by phospholipids increases the basal activity of adenylate cyclase (phosphatidyl serine) or restores its sensitivity to adrenaline and glucagon (phosphatidyl inositol). A reconstitution of the adenylate cyclase sensitivity to catecholamines by phosphatidyl inositol is also obtained after removal of the detergent excess using ion-exchange chromatography or lubrol PX replacement by cholate in the solubilized preparation. This restoration of the enzyme sensitivity to hormones is accompanied by an increase of the activating action of guanylylimidodiphosphate on the enzyme.