Nonlinear effects in kinetics of blood coagulation

A linear mathematical model of the kinetics of humoral system of hemocoagulation is presented in the works by Levin (1966), Moro a. Brakhucha-Reyd (1969), Martoran a. Moro (1974). Present paper considers a nonlinear mathematical model of the intrinsic path of hemocoagulation which takes into account the effect of positive feed back which is related to the action of factors Va and VIIIa as co-factors. It is found that the intrinsic path of hemocoagulation normally functions as an amplifier cascade, if the wall damage is above some threshold value. When the damage is below the threshold value the intrinsic path of hemocoagulation does not function.     

Trehalose matrix effects on electron transfer in Mn-depleted protein-pigment complexes of Photosystem II

The kinetics of flash-induced re-reduction of the Photosystem II (PS II) primary electron donor P₆₈₀ was studied in solution and in trehalose glassy matrices at different relative humidity. In solution, and in the re-dissolved glass, kinetics were dominated by two fast components with lifetimes in the range of 2–7 μs, which accounted for >85% of the decay. These components were ascribed to the direct electron transfer from the redox-active tyrosine Y_Z to P₆₈₀⁺. The minor slower components were due to charge recombination between the primary plastoquinone acceptor Q_A^? and P₆₈₀⁺. Incorporation of the PS II complex into the trehalose glassy matrix and its successive dehydration caused a progressive increase in the lifetime of all kinetic phases, accompanied by an increase of the amplitudes of the slower phases at the expense of the faster phases. At 63% relative humidity the fast components contribution dropped to ~50%. A further dehydration of the trehalose glass did not change the lifetimes and contribution of the kinetic components. This effect was ascribed to the decrease of conformational mobility of the protein domain between Y_Z and P₆₈₀, which resulted in the inhibition of Y_Z → P₆₈₀⁺ electron transfer in about half of the PS II population, wherein the recombination between Q_A^? and P₆₈₀⁺ occurred. The data indicate that PS II binds a larger number of water molecules as compared to PS I complexes. We conclude that our data disprove the “water replacement” hypothesis of trehalose matrix biopreservation.     

Effect of 6-hydroxydopamine on the ultrastructure of non-catecholaminergic elements of the dorsal hippocampus

As demonstrates the electron microscopical investigation, 6-hydroxidophamine possesses a wider sphere of influence than it was previously considered. It produces not only certain specific lesions in the hippocampal noradrenergic terminals, but also changes in non-catecholaminergic synapses; that is manifested as overfilling of the terminals with synaptic vesicles, lasting up to 24 h, and formation of vacuoles penetrating into invaginations of dendrites and astrocytes. The data obtained confirm the ideas of physiologists on modulating influence of the noradrenergic system on the noncatecholaminergic neural elements.     

Method of determining the quality of irrigation of the vessels of parenchymatous organs before injection]

The method suggested for qualitative estimation of the renal and hepatic vessels perfusion before an injection is based on measuring oscillations of the light beam diffused by the organ's surface (the source--a gas laser of continuous action of red spectrum). An absolute photometer protected by a red filter from external effects of light is used as a registrator. Successive injection of the renal and hepatic vessels with different masses and their investigation by means of roentgenography, preparation, carrosion demonstrate a satisfactory effectiveness of the method presented.     

Mitochondrial respiration and oxygen transport during various stages of lung inflammation

It is shown in rats with experimental lung inflammation that the phosphorylative and uncoupling mitochondrial respiration intensity rises at acute and reverses to the normal level at subacute inflammation. At chronic inflammation the 2,4-DNP-stimulated mitochondrial respiration enhances and the ADPO coefficient lowers. At all stages of inflammation the pO2 rise in muscles after O2-inhalation is less than in healthy animals. The disturbance of O2 transport in organism may be the reason of the described low energy shift at lung inflammation.     

Physicoсhemical Characteristics and Sorption Capacity of Biosynthetic Polymers Based on Ferulic Acid and Coniferyl Alcohol with Respect to the Zearalenone Mycotoxin

Russian Journal of Bioorganic Chemistry - The data on the chemical structure of the polymers, synthesized by the method of fermentative dehydropolymerization of ferulic acid, as well as coniferyl...     

Mutagenic activity of antineoplastic agents under conditions of normal and artificial modification

Mutagenic effect of vincristine, vinblastine, thiophosphamide, sarcolysine and the supermutagen ethyleneimine was studied in Crepis capillaris germinating seeds at the G phase. Metabolic conditions, prolongation of cell cycle, specific activity of preparation as well as inhibition of DNA synthesis were found to modify the mutagenic process induced by antitumour agents.     

Water-Organic Solvent Two-Phase Systems As Media For Biocatalytic Reactions: The Potential For Shifting Chemical Equilibria Towards Higher Yield Of End Products

This review emphasizes that the yield of the end products of chemical (biocatalytic) reactions in the two-phase system can, in principle, be much higher than in either medium (water or organic solvent) separately. A theoretical analysis of this phenomenon is presented and exemplified by some simple reactions.