Changes in the size of the myocardial damaged area in postischemic reperfusion

The changes in the size of the myocardial injury area during reperfusion after the coronary occlusion-induced ischemia lasting 30 minutes are phasic in nature. Until 3.5 h the injured area increases and after 23.5 h relatively diminishes. After a more prolonged ischemia such manifestations are either unmarked or absent. Ischemia lasting from 30 min to 4 hours followed by reperfusion, as compared with ischemia of the same duration without reperfusion, normally gives rise to the formation of an area of injury, which is less or occasionally equal in size. The data obtained and reported indicate that in the area of coronary occlusion there are groups of cardiomyocytes that differ as regards the resistance to ischemia.     

Individual human personality characteristics as a factor in the etiology of postvaccinal reactions

Healthy volunteers with quite opposite emotional properties defined by means of Cattell Personality Questionnaires were shown to have essential differences in their postvaccinal reactions. These differences were seemingly caused by psychoemotional tension developing in unstable persons as a result of their perception of vaccination as a threatening factor. The administration of Phenasepam (3 mg) decreased such emotional tension and thus removed negative reactions at the postvaccinal period. The preparation had no influence on the production of protective antibodies to all types of antigens used for immunization.     

Characteristics of the "no-reflow" phenomenon in reperfusion of the myocardium depending upon the duration of ischemia

The dynamics of changing dimensions of "no reflow" area following reperfusion after 30 min-1 h-long ischemia is characterized by three basic phases. The reperfusion following and hour-long ischemia altered considerably the character of phases of "no reflow" phenomenon. The data obtained suggest that the therapy of transitory ischemia must be directed not only to ischemia itself, but also to postischemia reperfusion-induced "no reflow" phenomenon.     

Dynamics of the level of extracellular dopamine in the rat brain during formation of conditioned fear and acoustic startle habituation

The content of extracellular dopamine (DA) was estimated in dorsal striatum (DS), nucleus accumbens (Nac), and prefrontal cortex (Pfc) of rat brain during two sessions of acoustic startle habituation consisting of 10 trials each with 24-hour intersession and 20-s intertrial intervals. Startle amplitude and freezing behavior were recorded. A decrease in the content of extracellular DA in the DS and an increase in the DA content in Nac were observed during both sessions of habituation with return to a baseline level immediately after termination of the sessions. During the second session, the startle amplitude and change in the DA content in both structures were much lower than during the first session. During the first session, the DA level in DS remained unchanged but dropped in Nac. In the Pfc the DA level increased during both habituation sessions and in the period between the session. Time of freezing prior to acoustic stimulation in the second sessions (that is known to be an indication of conditioned fear) correlated with the DA level in DS on the day of training and with the DA level in Nac just before the beginning of the second session. The role of the dopaminergic system in formation and retrieval of different components of defensive behavior is discussed.     

Regulatory role of monoamine neurotransmitters in Saccharomyces cerevisiae cells

Proliferation of Saccharomyces cerevisiae EPF cells on solid maltose-peptone-yeast extract (MPY) medium was stimulated by the addition of monoamine neurotransmitters. Dopamine turned out to be the most efficient among them: it caused approximately 8-fold growth stimulation at 1 microM concentration. The dopamine effect was partly mimicked by apomorphine, a dopamine receptor agonist. Serotonin and histamine produced less significant (1.5-2-fold) effects, and norepinephrine virtually failed to stimulate yeast culture growth. These data point to a specific, apparently receptor-dependent mode of action of the tested neurotransmitters on S. cerevisiae cells. Using high efficiency liquid chromatography, serotonin, catecholamines (dopamine and norepinephrine), catecholamines precursor dioxyphenylamine, and oxidized amine products (homovanilic acid, dihydrophenylacetic acid, and 5-hydroxyindolacetic acid) were established to be accumulated in yeast cells up to (sub)micromolar concentrations without their release into the culture fluid supernatant (CSF). The results obtained suggest that the tested amine neurotransmitters and related compounds do not serve as autoregulators in the yeast population. Nevertheless, they may be involved in the regulation of yeast population development by other ecosystem components.     

Human macrophage migration inhibitory factor: a proven immunomodulatory cytokine?

Macrophage migration inhibitory factor (MIF) is a pro-inflammatory mediator with the ability to induce various immunomodulatory responses and override glucocorticoid-driven immunosuppression. Some of these functions have been linked to the unusual enzymatic properties of the protein, namely tautomerase and oxidoreductase activities. However, there are conflicting reports regarding the functional role of these enzymatic properties in normal physiological homeostasis and disease progression. Therefore, we have produced a highly pure, virtually endotoxin-free recombinant MIF preparation and fully characterized this using a variety of biochemical and biophysical approaches. The recombinant protein, with demonstrable enzymatic activity, was then used to systematically examine the biological activity of MIF. Surprisingly, treatment with MIF alone failed to induce cytokine expression, with the exception of IL-8. However, co-treatment of lipopolysaccharide (LPS) in conjunction with MIF produced synergistic secretion of tumor necrosis factor-alpha, interleukin (IL)-1, and IL-8 compared with LPS alone. The potentiating effect of MIF was seen at physiologically relevant concentrations. These data suggest that MIF has no conventional cytokine activity but, rather, acts to modulate and amplify the response to LPS.     

Compensatory reaction during degeneration of arcuate nucleus dopaminergic neurons in rats

The study has been carried out to verify the authors' hypothesis that degeneration of dopaminergic (DA-ergic) neurons of the hypothalamic tuberoinfundibular system and concomitant development of hyperprolactinemia are accompanied by involvement of compensatory synthesis of dopamine (DA) by non-dopaminergic neurons expressing single complementary enzymes of synthesis of this neurotransmitter. Degeneration of DA-ergic neurons was produced by a stereotaxic injection into the brain lateral ventricles of 6-hydroxydopamine (6-OHDA) - a specific neurotoxin of DA-ergic neurons. 14 and 45 days after the toxin administration there were determined concentration of prolactine in peripheral blood by methods of immunoenzyme and radioimmunological analyses as well as the DA amount in the arcuate nucleus by the method of highly efficient liquid chromatography with electrochemical detection. In a part of the animals, slices were prepared from the mediobasal hypothalamus (arcuate nucleus and medial eminence) and perfused with Krebs-Ringer medium; then the DA concentration was determined in the slices and in the incubation medium. 14 days after the neurotoxin administration there were revealed an increase of blood prolactine concentration and a decrease of DA concentration in the arcuate nucleus in vivo as well a decrease of the total DA amount in the slices and incubation medium in experiments in vitro. 45 days after the neurotoxin administration, all the above parameters returned to the normal level. This, the obtained data indicate that the hyperlactinemia and DA deficit appearing during degeneration of the arcuate nucleus DA-ergic neurons seem to be compensated due to an enhancement of DA synthesis by non-dopaminergic monoenzyme neurons of arctuate nucleus.     

Stereospecificity of the effect of flupenthixol isomers on the substrate inhibition of brain tyrosine hydroxylase

Stereospecificity of the effect of neuroleptics on substrate inhibition of isolated brain tyroxine hydroxylase is shown. Flupentixole cis-isomer eliminates substrate inhibition of the enzyme. The effect is concentration-dependent and is well marked within the tyrosine concentration range 10-6-10-4 M. Flupentixole trans-isomer in the same concentrations has no effect on substrate inhibition of tyrosine hydroxylase. In the presence of cis-flupentixole, the reaction rate plotted against tyrosine concentration is a hyperbole with a plateau at 160-360 microM tyrosine. In the presence of trans-isomer, as in the control sample, the relationships between the reaction rate and tyrosine concentration are depicted by a curve with a maximum (at 110-140 microM tyrosine). Like ftorphenazine, flupentixole isomer fails to eliminate the inhibitory action of alpha-methyl paratyrosine, which indicates the interaction of neuroleptics with the tyrosine-binding site of the enzyme molecules in the noncatalytic centrer. It is suggested that the interaction of the neuroleptics with the regulatory area of tyrosine hydroxylase might by important in the molecular mechanism of their action.     

The role of the adrenals in the development of hyperenzymemia in experimental multiple injuries]

The authors studied the activity of acid phosphatase (AP), lactic dehydrogenase (LDH), aspartic and alanine-aminotranspherases (AST and ALT) in the serum of rats with intact and removed adrenal glands after a severe multifocal trauma induced according to Noble-Collip (300 rpt of the drum with the rotation speed of 37 rpt/min). Adrenalectomy showed practically no influence on the dynamics of the LDH and AP activity. An increase in the activity of the AST and especially of the ALT in the serum of adrenalectomized rats after the trauma was considerably less than in the animals with the intact adrenal glands.     

Effect of ethanol on the levels of dopamine and its metabolites in the brain of rats with different degree of sensitivity to stress

It was shown, that content of dopamine and its metabolites (DOPAC and HVA) are the same in two groups of rats with different time of immobilization in forced swimming test. One group of low active (LA) animals experienced the immobilization more than 300s, other high active (HA) rats for less than 120 s. Ethanol (2 g/kg per oris) increased the level of DA in the striatum and medial prefrontal cortex only in LA rats and besides, the concentration of dopamine after ethanol administration was higher in the n. accumbens of LA rats, than in that of HA rats. The authors suggest that differences in dopamine content between LA and HA rats are connected with different levels of voluntary alcohol consumption. The opportunity to use both groups of HA and LA rats for developing models of pathogenic heterogeneity of alcoholism is discussed.