Peptide Epitalon activates chromatin at the old age

OBJECTIVES and design. We have studied the effect of synthetic peptide Epitalon on the activity of ribosomal genes, denaturation parameters of total heterochromatin, polymorphism of structural C-heterochromatin and the variability of facultative heterochromatin in cultured lymphocytes of persons aged 76-80 years. RESULTS: The obtained data demonstrate that Epitalon induces the activation of ribosomal genes, decondensation of pericentromeric structural heterochromatin and the release of genes repressed due to the age-related condensation of euchromatic chromosome regions. CONCLUSIONS: Epitalon has shown its ability to activate chromatin by modifying heterochromatin and heterochromatinized chromosome regions in the cells of older persons.     

Modulation of voltage-gated sodium channels by recombinant interferon-alpha2b in the human neuroblastoma cell line IMR-32

Clonal human neuroblastoma cells imr-32 are a suitable model system for studies of neuronal excitability modulation. The ability interferon-alpha 2b "laferon" to modulate the mechanisms of electrical activity was studied in whole-cell patch-clamped undifferentiated human neuroblastoma cells IMR-32. It was shown that 1 h incubation of IMR-32 cells at 37 degrees C in medium with laferon (600 U/ml) exerted changes in voltage-dependent properties of Na(+)-channels. The results of the present study demonstrate that laferon decreased of Na(+)-channels sensitivity to changes of membrane potential leading of IMR-32 cells electrical excitability decrease.     

Comparison of the Protection against Neuronal Injury by Hypothalamic Peptides and by Dexamethasone

The comparative study has been carried out on hypothalamic neurohormone (proline-rich polypeptides-PRP) and synthetic glucocorticoid dexamethasone (DEX) protective properties at the systemic (i/m) administration. Both background and evoked electrical activity (on n.ischiadicus stimulation) of single neurons in the lumbo-sacral part (laminae II–VI and VII–VIII by Rexed) and field potentials (FP) of spinal cord were recorded during acute experiments on intact spinal rats, subjected to Vipera Raddei (VR) venom intoxication, and chronic spinal cord trauma (hemisection). The action of PRP was characterized by the pronounced activation of the background activity (BA) with adaptive effect, depending on dose and initial level of BA, by results of the statistical analysis. A high effect is received from comparatively small doses. For comparison it was used strong glucocorticoid DEX, possessing single-directed but less expressed excitative action on investigated spinal cord neurons. The initial increase of BA frequency with subsequent depression was the typical symptom of venom influence. A protective effect of preliminary PRP injection is revealed on the succeeding VR venom influence. Use of PRP and DEX causes the increase of reduced activity of neurons on the injury side of animals with spinal cord hemisection. It provides the possibility of the therapeutic utilization. It was revealed considerably more expressed PRP action on neurodegenerative process connected to spinal cord injury (in comparison with DEX). The influence of hormones was compared in identical conditions of experiments on non-injured (control) and injured sides. Taking into consideration revealed protection characteristic of PRP and also the ability of snake venom to stabilize and to prolong its action combined with these preparations, the assumption is made on prospective use of the specified combination in clinical practice.     

Protection Against Snake Venom-Induced Neuronal Injury by the New Hypothalamic Neurohormone

The action of PRP is characterized by the pronounced activation of the background activity (BA) of the brain spinal cord, and the degree of the activity depends on BA initial level. The typical peculiarity of Vipera raddei venom influence is the initial increase in frequency of BA with subsequent depression. A preliminary injection of PRP has a protective effect at subsequent influence of venom. In animals with hemisection the PRP increases the decreased activity of neurons on injury side. Taking into consideration the protective peculiarities of PRP in the relationship to snake venom and the possibility of the latter to stabilize and prolong the action of drugs (in the case of PRP) combined with them, it is supposed that the mentioned use of the combination in clinical practice will be perspective. The data obtained testify the PRP to be a neuroprotector against many toxic compounds formed in organism (glutamate, ceramid, beta-amyloid neurotoxisity, etc.). Investigations in this aspect are still in the process.     

The effect of the substance exin on development of microbial infections and isolation of ethylene in plants

Effects of Exin on infection of tomato, potato, and cabbage plants with Pseudomonas solanacearum and Erwinia carotovora and a fungus Sclerotium rolfsii were studied. The treatment of infected plants with Exin caused no significant effect on the development of the disease. Treatment with streptomycin as a standard for comparison completely inhibited the growth of these microorganisms. Pretreatment with Exin one to eight days before infecting inhibited the development of diseases. The numbers of tomato and potato plants damaged among those infected with P. solanacearum were lower by 10 and 35% respectively. In field experiments (350 plants per variant), treatment with Exin decreased the development of wilt caused by S. rolfsii and P. solanacearum and rot caused by E. carotovora. Treatment with Exin activated the release of ethylene for not less than 30 days. Possible mechanisms of the effects of Exin are discussed.     

Microsampling of rhizosphere soil and laboratory artefacts

A parallel analysis of the microsamples of surrounding soil and microsamples of rhizosphere soil did not reveal the so-called rhizospheric effect. The data obtained showed that dilution significantly influences the results of determination of the number of soil microorganisms. The actual number of microorganisms revealed in soil samples greatly differed from the theoretically predicted values. The enumeration of microorganisms in soil microsamples by direct count and, especially, by the plating method with the use of conversion coefficients based on the degree of sample dilution gave erroneous results.     

Synchronization of secretion of the evoked transmitter quanta as mechanism of the facilitating action of sympathomimetics

Noradrenaline, isoproterenol, dobutamine were found to modulate kinetics of quanta secretion so as to synchronize the transmitter release. This effect could be prevented with blocking agents of beta-adrenoreceptor (atenolol, propranolol). Activators of beta-adrenoreceptors klonidine and phenylephrine did not change the kinetics of quanta secretion, whereas phentolamine did not affect the synchronizing effect of noradrenaline. The change in the time course of the secretion induced by noradrenaline increased the end-plate current amplitude. There seems to exist a specific presynaptic mechanism involving beta-adrenoreceptors for facilitation of effects of sympathomimetics.