Photodynamic effect of deuteroporphyrin IX and hematoporphyrin derivatives on single neuron

The photodynamic effects of 6 new deuteroporphyrin IX derivatives with different amphiphilicity and lipophilicity, as well as effects of known hematoporphyrin derivatives Photofrin II and Photoheme on isolated crayfish mechanoreceptor neurons were studied. After 30 min photosensitization, neurons were irradiated with He-Ne laser (632.8 nm, 0.3 W/cm(2)), and changes in their firing frequency were recorded. Neuron firing was shown to be very sensitive to photodynamic effect of the studied deuteroporphyrin IX derivatives causing irreversible firing abolition at pikomolar concentrations while Photoheme and Photofrin II were effective in the nanomolar range. The most effective sensitizers were 4-(1-methyl-3-hydroxybutyl)- and 4-(1-methyl-2-acetyl-3-oxobutyl)-deuteroporphyrins. Extinction and amphiphilicity were shown to be the most important properties determining photodynamic efficiency of the studied photosensitizers.     

Ratio of elements in humic acids as a source of information on the environment of soil formation

This paper considers the informative importance of one of the main features that characterize humic acids of soils at the diagnosis of the natural environment of their formation in both the present and the past. It is shown that the ratio of elements in the humic acids clearly corresponds to the landscape conditions and quantitative characteristics of climatic parameters. They persist over time and can serve as one of the reliable indicators in assessing the environment of different periods of paleogeographic history.     

A single neuron response to photodynamic effect of various aluminum and zinc phthalocyanines

The photodynamic effects of sulphonated zinc and aluminum phthalocyanine derivatives as well as phosphonated aluminum phthalOcyanine on the firing of isolated crayfish mechanoreceptor neurons were studied. After 30 min staining neurons were irradiated with He-Ne laser (632.8 nm, 0.3 W/cm2) and changes in neuron firing frequency were recorded. Neuron firing was found to be very sensitive to photodynamic effect and could serve as a sensitive indicator of cell photodamage. It changed the firing level and then died at nanomolar concentrations of phthalocyanines. The dynamics of the neuron responses to photodynamic effects included stages of firing activation and/or inhibition prior to irreversible firing abolition. The order of these stages depended on photosensitizer type and concentration. The comparison of the dependencies of neuron lifetime on photosensitizer concentrations showed ZnPcS2 to be the most effective photosensitizer.     

Experimental assessment of the ability of different species of sandfly to transmit the causative agent of visceral leishmaniasis

The authors succeeded in transmission of the visceral leishmaniasis agent (kazakh strain of Leishmania infantum) through the sand flies Phlebotomus longiductus, P. smirnovi and P. papatasi under experimental conditions. Infected P. longiductus and P. smirnovi are capable of preserving the agent and infecting the susceptible mammals after the cessation of the 1st and 2nd gonotrophic cycles. P. papatasi transmitted the agent of visceral leishmaniasis only after the cessation of the 2nd gonotrophic cycle. Under the same conditions the transmission of visceral leishmaniasis agent through P. caucasicus failed. Informative value of characteristics of virtual vectors for differentiation of sand flies as carriers is analysed. A question of the necessity of obtaining additional data, which prove the role of P. caucasicus and P. papatasi as vectors of visceral leishmaniasis agent, is raised.     

The role of the posterior hypothalamus in the regulation of paradoxical sleep

Posterior hypothalamus was found to take part in the inhibitory control of the paradoxical sleep executive mechanisms responsible for the ECoG desynchronisation and phasic events. Functional activity of the posterior hypothalamus seems to be at its lowest during the paradoxical sleep stage as characterised by phasic events and the ECoG desynchronisation, and increases during the stage with alpha-like activity in the ECoG and absence of phasic events, the latter having, probably, a "sentinel" function.     

Humus profiles of Siberian soils under different forming conditions

Humus profiles of Siberia soils under different conditions and models of soil formation are considered in the paper. It is shown that the humus profiles of soils formed in the regions of displacement of landscape and soil borders and developed according to the polygenetic model as well as the soils of synlithogenous type of pedogenesis have a complicated structure. Simple structure of the humus profile characterizes soils developing within the framework of a simple (ideal, normal) model of soil formation.     

Ecology of soils: a new science of the biosphere class

The history of a new science, ecology of soils, is described. Its object, subject, and methodology are discussed, with emphasis placed upon the top-priority problems. It has been proved that ecology of soils is among the sciences whose concern is the study of biosphere. Examples are given to illustrate rules and laws of the new science. It is shown in particular that humus components and their ratios are bearing on climate parameters and fall on definite ecological ranges of certain kinds of soils characterized by different ratios of humic acids.     

Morphofunctional changes in the adrenergic innervation of the major cerebral arteries during bilateral electrostimulation of the locus coeruleus

The intramural adrenergic nervous apparatus of cerebral arteries was studied in adult rabbits after 3-10 sessions of electrical stimulation of locus coeruleus. The activity of nerve structures was determined by estimating the density of adrenergic perivascular plexuses and by semi-quantitative cytophotometry of changes in the catecholamine content of nerve varicosities. The stimulation was followed by a 28.2 +/- 1.5% increase in adrenergic innervation density. while catecholamine content in perivascular nerve structures displayed a tendency to decrease. The problem of central effects on cerebral blood flow autoregulation is discussed.