Molecular Dynamics and Experimental Study of the Effect of CeF and NdF Additives on the Physical Properties of FLiNaK.

The paper presents the results, which are consistent within 2%, obtained both in the simulation of molecular dynamics and in the experiment on the study of the kinetic properties of molten FLiNaK with addition of lanthanide fluorides. The parameters of the Born-Huggins-Meier potential for the interaction of CeF or NdF with FLiNaK components are first calculated using the ab initio approach. The enthalpy of the system with dissolved CeF or NdF calculated in the model increases by ∼4.

[Challenges of expert assessment of injury to health in the case of iatrogenic mastectomy due to erroneous histological verification of an oncological condition].

A case of commission forensic medical examination in the St. Petersburg Bureau of Forensic Science of a civil case due to an unfavorable treatment outcome is presented. Patient , 45 years old; due to erroneous histological verification of oncological pathology, she had both breasts removed and received antitumor treatment.

Dynamic Viscosity of the NaF-KF-NdF Molten System.

The dynamic viscosity (η) of the molten system (NaF-KF)-NdF containing NdF in an amount from 0 to 15 mol.% was studied by rotational viscometry using a high-temperature rheometer, FRS 1600. Viscosity measurements were carried out in the temperature range from liquidus to 1153 K.

Action of tannin on cellular membranes: Novel insights from concerted studies on lipid bilayers and native cells.

Hydrolyzable tannin (3,6-bis-O-digalloyl-1,2,4-tri-O-galloyl-β-d-glucose) has a dual effect on the cell membrane: (1) it binds to a plasmalemmal protein of the Chara corallina cell (C = 2.7 ± 0.3 μM) and (2) it forms ionic channels in the lipid membrane.

A Characeae Cells Plasma Membrane as a Model for Selection of Bioactive Compounds and Drugs: Interaction of HAMLET-Like Complexes with Ion Channels of Chara corallina Cells Plasmalemma.

Interaction of a HAMLET-like La-OA cytotoxic complex (human α-lactalbumin-oleic acid) and its constituents with the excitable plasmalemma of giant Chara corallina cells was investigated. The voltage-clamp technique was used to study Ca and Cl transient currents in the plasmalemma of intact cells. The action of the complex and OA on the target cell membrane has a dose-dependent character.

HALOPERIDOL MODULATES IONIC TRANSPORT OF CHARA CORALLINA CELLS.

The effect of the haloperidol (HP), a dopamine D2-receptor antagonist on the function of ionic channels of the electrically excitable plasma membrane and on the cytoskeleton of Chara corallina cells was investigated. Haloperidol was shown to block plasmalemmal Ca2+ channels. Apart from Ca2+ current reduction, the presence of HP slowed the kinetics of both activation and inactivation of ionic channels.

Bacillus cereus can attack the cell membranes of the alga Chara corallina by means of HlyII.

We studied the influence of Bacillus cereus bacteria on cells of the freshwater alga Chara corallina. These bacteria and recombinant Bacillus subtilis strains are capable of producing the secreted toxin HlyII, which changes the electrophysiological parameters of the algal electrically excitable plasma membrane by forming pores. Cooperative incubation of bacterial cells, which carry active hlyII gene, and Chara corallina cells caused a decrease in the resting potential (V(m)) and plasma membrane resistance (R(m)) of algal cells.

[Trabeculae and the intertrabelcular tissue during the contraction of the frog atrium at decreased temperatures and sodium ion concentrations in solution].

Data characterizing the kinetics of the contraction of trabeculae and the intertrabelcular tissue have been obtained. It has been concluded that trabeculae can act as conductors/transmitters of contraction across the myocardium and play a leading role in this process, while the functional role of the intertrabelcular tissue is secondary and more passive, and consists in the optimization and support of the contractile process.

Interaction of antitumor alpha-lactalbumin-oleic acid complexes with artificial and natural membranes.

The specific complexes of human alpha-lactalbumin (alpha-LA) with oleic acid (OA), HAMLET and LA-OA-17 (OA-complexes), possess cytotoxic activity against tumor cells but the mechanism of their cell penetration remains unclear. To explore the molecular mechanisms underlying interaction of the OA-complexes with the cell membrane, their interactions with small unilamellar dipalmitoylphosphatidylcholine (DPPC) vesicles and electroexcitable plasma membrane of internodal native and perfused cells of the green alga Chara corallina have been studied. The fractionation (Sephadex G-200) of mixtures of the OA-complexes with the vesicles shows that OA-binding increases the affinity of alpha-LA to DPPC vesicles.

[Slow Ca2'-binding Mg2+- EDTA buffer for intracellular perfusion].

In studies of currents in perfused cells or their membrane fragments containing potential-dependent Ca channels and Ca2+-activated channels, a buffer slowly binding Ca2+ appears useful in some cases. A buffer with EDTA in excess of Mg2+ has been proposed, and its kinetic characteristics have been calculated. It has been shown that this buffer, depending on its component proportions, may provide Ca2+ binding with a characteristic time of up to tens of milliseconds.

[Transient currents and Ca2+ gradient relaxation in characean algae cells: theory and experiment].

Transient Ca2+ and Ca2+-dependent Cl- currents of plasmatic membranes of voltage-clamped Chara corallina freshwater alga cells were studied. Our earlier described method was used for rapid (approximately 10 ms) injection of Ca2+ ions into the cell during the deactivation period of calcium channels following their activation by a positive voltage pulse (injection by "tail" Ca2+ current). This procedure allowed one to determine the amplitude of the Ca2+ component, as well as the amplitude and kinetics of the submembrane Ca2+ concentration-dependent Cl- component for the transient current.

Voltage-gated calcium and Ca2+-activated chloride channels and Ca2+ transients: voltage-clamp studies of perfused and intact cells of Chara.

The voltage-clamp technique was used to study Ca(2+) and Cl(-) transient currents in the plasmalemma of tonoplast-free and intact Chara corallina cells. In tonoplast-free cells [perfused medium with ethylene glycol bis(2-aminoethyl ether)tetraacetic acid] long-term inward and outward currents through Ca channels consisted of two components: with and without time-dependent inactivation. The voltage dependence of the Ca channel activation ratio was found to be sigmoid-shaped, with about -140-mV activation threshold, reaching a plateau at V>50 mV.

[Effect of avermectns on Ca(2+)-dependent chloride currents in plasmalemma of Chara corallina cells].

A natural complex of avermectins, aversectin C, and a component of this complex, avermectin A1, were shown to change the conductivity of Ca(2+)-dependent chloride channels of plasmalemma of Chara corallina cells by acting only from the outer side of the cellular membrane. Low concentrations of aversectin C and avermectin A1 increased the chloride current: K1/2 = 3.5 x 10(-5) mg/ml for the whole complex and K1/2 = 2.

Through pore diameter in the cell wall of Chara corallina.

Determination of pore size of the cell wall of Chara corallina has been made by using the polyethylene glycol (PEG) series as the hydrophilic probing molecules. In these experiments, the polydispersity of commercial preparation of PEGs was allowed for. The mass share (gamma(p)) of polyethylene glycol preparation fractions penetrating through the pores was determined using a cellular 'ghost', i.

Effect of avermectins on Ca2+-dependent Cl- currents in plasmalemma of Chara corallina cells.

A natural complex of avermectins, aversectin C, and a component of this complex, avermectin A1, were shown to change the conductivity of Ca2+-dependent Cl- channels of plasmalemma of Chara corallina cells by acting from the outer side of the cellular membrane. Low concentrations of aversectin C and avermectin A1 increased the Cl- current: K1/2 = 35 ng/ml for the whole complex and K1/2 = 21 pg/ml for A1. Relatively high concentrations of the compounds suppressed the Cl- current: K1/2 = 2.

[Allowing for polymer polydispersity--an essential condition for determination of aqueous pore diameters in cell walls and membranes using polymers].

A method of allowing for polydispersion of polyethylene glycol (PEG) preparations was developed for the use of these preparations for the osmometrical evaluation of pore diameters with aqueous pores of Chara corallina cell walls as an example. The mass share of polyethylene glycol preparation fractions gamma p penetrating through the pores was determined using cellular "shadows", fragments of internodal cell walls tied up at the ends and filled with a 25% solution of nonpenetrating PEG 6000. When immersed into water, such "shadow" acquired a turgor (hydrostatic) pressure close to the cellular pressure and persistent over long time.

D2O-induced ion channel activation in Characeae at low ionic strength.

Effects of D2O were studied on internodal cells of the freshwater alga Nitellopsis obtusa under plasmalemma perfusion (tonoplast-free cells) with voltage clamp, and on Ca2+ channels isolated from the alga and reconstituted in bilayer lipid membranes (BLM). External application of artificial pond water (APW) with D2O as the solvent to the perfused plasmalemma preparation led to an abrupt drop of membrane resistance (Rm = 0.12 +/- 0.