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The effect of synthetic anti-oxidant potassium phenosan (PP, potassium salt of beta-(4-hydroxy-3,5-ditretbutil-phenyl)-propionic acid) on the structural state of the surface (8 angstroms) and deep (20-22 angstroms) lipid regions of plasma membranes of mice liver cells was studied by spin probes method in vitro in a wide range of concentrations (1(-5)-10(-21) M). Two stable free radicals, 5- and 16-redox-stearic acids (C5 and C16), were used as spin probes. The nonlinear polymodal dose-effect dependences were obtained for parameters that characterize the microviscosity of the lipid bilayer (tau(c)) in the site of localization of the probe C16, and the order parameter (S), which characterizes the stiffness of the surface layers of lipids in the site of localization of the probe C5. Statistically a reliable increase was observed for parameter tau(c) after addition of PP at concentrations 10(-5)-10(-7) M and 10(-18)-10(-19) M, and for parameter S after addition of PP at concentrations 10(-6)-10(-7) M and 10(-13)-10(-15) M. Peaks on both dose-effect curves were separated by the intervals of concentrations where PP had no effect on the studied physico-chemical characteristics of biomembranes. For PP concentrations which caused maximal changes in tau(c) and S, we investigated thermal dependence of these parameters and determined the thermally induced structural transitions. Comparing with control, ultra-low doses of PP (10(-13)-10(-15) M) and (10(-18)-10(-19) M) caused an appearance of additional thermally induced structural transition in the surface and deep regions of plasma membrane lipids. The possible role of the interaction of PP molecules with specific binding sites on plasma membranes and formation of nanoparticles of PP in very dilute aqueous solutions are discussed.

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The effect of the natural antioxidant alpha-tocopherol in a broad concentration range (10(-4) - 10(-25) M) on the viscosity characteristics and thermally induced structural transitions of a lipid bilayer of plasma membranes of murine hepatocytes in vitro has been studied. Changes in the rigidity of surface (approximately Abb) of the lipid bilayer were measured on a Bruker EMX EPR spectrometer (Germany) by the method of spin probes. Stable nitroxyl radicals of 5- and 16-doxylstearic acid, localized at different depth in the membrane served as spin probes. It was shown that the concentration dependence of the effect of alpha-tocopherol is linear and polymodal with three statistically significant increases in three ranges of its concentration: (1) in the range of traditional physiological concentrations 10(-4)-10(-9) M, (2) in the range of superlow doses 10(-9) - 10(-17) M, and (3) in the range of "imaginary" concentrations 10(-17) - 10(-25) M. The mechanisms of action of alpha-tocopherol in each of the three ranges are discussed. When studying the temperature dependences of viscous characteristics, a new thermally induced structural transition in the range of "physiological" temperatures 309-313 K for those alpha-tocopherol concentrations (including superlow ones) to which the maxima on the dose dependence curves at constant temperature of 293 K corresponded.

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A new class of substances exhibiting radioprotective and radiosensitizing effects depending on the concentration of the substance has been found. The radioprotective effect is probably due to the resonant absorption of radiation energy and its transformation into low-energy forms, as well as reactions with water radiolysis products. We studied the effects of 2,5-difeniloxazole and di[2-(5-feniloxazolil)]benzene in various concentrations in conjunction with irradiation on the growth of melanoma B-16 in mice and the average time of their lives. When using individual doses of irradiation and doses of preparations, we observed an increase in the average lifetime of mice and a reduced tumor size. These data allow us to conclude about the possibility of using these substances in the radiotherapy of tumors.

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The effect of alpha-tocopherol (alpha-tp) prepared in solvents of different polarity in a wide range of concentrations (10(-4) M - 10(-25) M) on lipid phase structural characteristics of microsomal membranes isolated from mouse liver cells has been investigated in vitro. Structural changes in membranes were detected on a Bruker-200D ESR-spectrometer (Germany) by the method of spin probes. Changes in the rigidity of surface lipid bilayer regions (8 A) and microviscosity of deep membrane layers (20 A) were studied using the stable nitroxyl radicals 5- and 16-doxylstearic acids, correspondingly. As a result, nonlinear multimodal dose dependences were obtained. It was demonstrated that the physiological (10(-4) M - 10(-9) M) and ultralow doses of alpha-tocopherol up to "apparent" concentrations (10(-11) M - 10(-25) M) increased the rigidity of surface lipid bilayer regions and microviscosity in the depth of membrane. Additionally, these doses of alpha-tp induced an increase in the number of thermoinduced structural transitions in deep lipid bilayer regions. The effect at "apparent" concentrations (< 10(-18) M) has only been observed in polar alpha-tocopherol solutions. The results obtained are statistically reliable with a significance level of 95%.

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The spin probe method was employed to study in vitro the effect of regulatory peptide thyroliberin on structural state of surface (0.8 nm) and deep (2 nm) lipid layers of the plasma membranes in mouse liver and brain. Thyroliberin in a concentration range of 10(-3)-10(-18) M enhanced structural order of surface lipids, the maximum effect was observed at 10(-9)-10(-10) M. The dose-effect dependencies for microviscosity of deep lipids were nonlinear and had 3 extrema at 10(-4)-10(-7) M, 10(-9) M, and 10(-14)-10(-16) M. The greatest changes in lipid microviscosity produced by 10(-9) M thyroliberin are explained by lipid-receptor interaction.

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Synthetic antioxidant potassium phenosan in ultralow doses administrated in combination with antitumor antibiotic adriamycin in a therapeutic dose (8 mg/kg) markedly prolonged the mean life span of tumor-bearing animals compared to adriamycin monotherapy. This effect depended on the dose of antioxidant and was maximum at phenosan concentrations of 10(-17) and 10(-15) M. Potassium phenosan in these concentrations not only increased the mean life span, but also determined survival of 10-20% animals (as differentiated from adriamycin monotherapy).

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The action of 12-O-tetradecanoyl-13-acetate (TPA) in vitro in a wide range of concentration from 10(-3) mol/l down to ultra-low doses 10(-23) mol/l and dilution 10(-24) mol/l on the microsome membranes isolated from tumor--Ehrlich ascite carcinoma (EAC) has been studied by ESR-method using two spin probes: 5- and 16-doxyl stearates (5- and 16-DS) localized in the different regions of lipid bilayer. From the ESR spectra obtained it was calculated the following parameters: an order of the long axis 5-DS (S) related to order of the fatty acids chains in the lipid bilayer; two rotation correlation times (Tc1 and Tc2) of 16-DC to estimate a microviscosity value and structural-sensitive ones. It was found the stage changes of all these parameters (increase and decrease) as compared with control level (the membranes untreated by TPA) depending on TPA concentration into the range of 10(-3)-10(-24) mol/l; in particular, the most significant shape changes of structural-sensitive parameters have been observed at TPA doses below 10(-16) mol/l. It is concluded that tumor membranes are very sensitive to TPA action in vitro in a wide range of concentration included ultra-low doses.

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On the basis of antioxidant (alpha-tocopherol and phenosan potassium salt) and peptide (thyroliberin) effects on the lipid peroxide oxidation (LPO) and lipid structural parameters of the endoplasmic reticulum membranes in wide concentration range (10(-20)-10(-4) mol/l) in vitro the possibility concerning a proposed role of "super-affine" receptors in the mechanism of biologically active substances (BAS) action in ultra low doses (ULD) is discussed. Because these substances modulate investigated processes in the membranes which have not ordinarily receptors the conclusion about availability of non-receptor component in the mechanism of BAS effect in ULD and a low probability of "super-affine" receptor existence has been done.

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Thyroliberin (TRH) influence on microviscosity and thermoinduced structural transitions of biological membranes has been studied using spin probes and ESR technique. It was shown that TRH in three investigated concentrations (10(-6), 10(-10) and 10(-16) mol/l) in vivo resulted in increasing of the lipid microviscosity in the hydrophobic areas (20 A): the time of rotary correlation of 16-doxyl-stearic acid elevated by 17-50%. There were no statistically significant effects in the regions localized more close to the surface (8 A): the order parameter of 5-doxyl-stearic acid was not changed. The picture of thermoinduced structural transitions in described in this article. Under the action of TRH in vivo both the shift of structural transitions and the changes in their number have been observed. The results obtained indicated that the mechanism of the TRH effect has a non-receptor component.

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The aim of the present work was to study by ESR-spin-probe technique the effect of the natural antioxidant alpha-tocopherol (alpha-tp) in vitro on the structural parameters (microviscosity, order parameter) of endoplasmic reticulum membranes of the mice liver cells starting from the concentration of 10(-3) mol/l and down to the dilution of 10(-25) mol/l. The stable nitroxyl radicals 16-doxylstearic acid (with the deep localization depth of 20 A) and 5-doxylstearic acid (with the surface localization depth of 8 A) were used as spin probes. It has been shown that alpha-tp causes the increase in microviscosity of the deep lipid bilayer regions and in rigidity of the surface ones at the certain concentrations. The concentration curves obtained have the polymodal shapes being typical of the effects of substances at ultra low doses. Using 16-doxylstearic acid it is detected the increase in the number of thermoinduced structural transitions and appearance of much more high-cooperative ones, as well as the increase in their effective activation energy with the rise of temperature at the supplement of different alpha-tp doses.

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Peptides are known to have the ability of modulating the activity of important regulatory cellular systems. One of them--thyroliberin, i.e. thyreotropin-releasing hormone (TRH), causes changes in the membrane structure and morphology of rat erythrocytes, as well as activates retractive activity of lymphatic vessels in ultra low concentrations (10(-10) to 10(-16) mol/l). In this study we used an electron spin resonance (ESR) method to explore the effect of TRH in a wide range of concentrations (10(-4) to 10(-18) mol/l) on thermo-induced structural transitions and microviscosity of lipid bilayer of the endoplasmic reticulum membrane of mice (C57 bI) liver cells. Two stable free radicals were used as paramagnetic probes: 2,2,6,6-tetramethil-4-capryolyl-1-oxyl and 16-doxyl-stearic acid, that are localized in superficial and deep layers of the membrane respectively. TRH caused a statistically significant change (p < 0.001) in microviscosity of the membrane surface layer. The largest effect (up to 30% decrease) was observed at TRH concentrations of 10(-10) and 10(-16) mol/l. It was also demonstrated that an addition of 10(-4), 10(-10) and 10(-16) mol/l of TRH decreases effective activation energy and temperature (by several degrees) of the thermo-induced structural transitions. The observed changes in the parameters of the membrane surface layer induced by TRH may be essential for its physiological activity, because of the obtained negative correlation (r = 0.99; p < 0.001) between the membrane microviscosity and frequency of lymphatic vessels' contraction. Complex changes in the structure of deep hydrophobic layer of the membrane caused by TRH were observed in this study as well. Higher concentrations of TRH (10(-4) and 10(-10) mol/l) produced results that were similar to the effect of TRH on the superficial lipid layer of the membrane, whereas the effect of ultra low TRH concentration (10(-16) mol/l) was reversed for microviscosity, number and activation energy of structural transitions in contrast with the case of surface layer. The results of this study suggest presence of a nonspecific factor in the effect of TRH on structural characteristics of the lipid component of biological membranes. It is possible, that the change of structural properties of biological membranes may be a part of the mechanism of TRH action at ultra low concentrations.

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Acetylcholinesterase (ACE) activity and lipid peroxidation (LPO) parameters were measured in the blood of patients with Alzheimer's disease (AD) during treatment with amiridine and gliatiline. Treatment was accompanied by inhibition of ACE. There was a statistically significant relationship between clinical efficacy and changes in ACE activity. AD was charactefized by significant changes in LPO parameters, with a three-fold increase in the level of primary oxidation products on the background of a sharp (seven-fold) increase in total lipid desaturatedness. There was a statistically significant relationship between ACE activity and the levels of primary oxidation products in the RBC of patients with AD before and after treatment with amiridine and gliatiline.

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Acetylcholinesterase (AChE) activity and parameters of the system of regulation of lipid peroxidation (LPO) were estimated in blood of patients with Alzheimer's disease (AD) during therapy with amiridine and gliatiline. It was found that the therapy was accompanied by inhibition of AChE activity. A significant correlation was observed between clinical efficiency and changes of AChE activity. AD was characterised by essential changes in LPO parameters: the level of the primary products of oxidation was increased three times with a sharp increase (seven times) of total unsaturation of lipids. A significant correlation was found between AChE activity and the level of the primary products of oxidation in blood erythrocytes of AD patients before and after therapy with amiridine and gliatiline.

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The changes in the microviscosity of the nuclear membranes of tumor and liver cells of tumor hosts with developing Erlich ascites carcinoma at different times after irradiation of lethal dose has been studied by spin probe method. Using two iminoxyl radicals localized in various lipid regions, it was shown that the character and degree of changes in microviscosity, estimated from rotational correlation time for spin probes, indicate the different response to irradiation of liver and tumor cells.

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The effect of the natural antioxidant alpha-tocopherol (alpha-TL) on protein kinase C (PK-C) from rabbit heart has been studied. alpha-TL inhibits the PK-C activity; the concentration dependence curve has two maxima-at (10(-4)-10(-6) M) and at (10(-11)-10(-15) M). There is a "zone of silence" between these two regions. The shift of the first maximum towards higher alpha-TL concentrations (5 x 10(-3) M) and the decrease in the values of the both inhibition maxima (from 80-90% to 40-60%) was observed for the PK-C preactivated by 12-O-tetradecanoyl-phorbol-13-acetate. The putative role of alpha-TL and lipid hydroperoxides in the regulation of proliferation of normal and tumour cells is discussed.

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Inactivation of naloxone binding to rat brain membrane-bound mu-opioid receptors (37 degrees C) was studied using the radioligand method. The rate inactivation constant (k(in) = 5.2 +/- 1.0 x 10(-3) min-1), the activation energy (Ea = 82.5 kJ/mol) and the change in the activation entropy (delta S = -14 kJ/K.mol) were determined. Incubation with unsaturated fatty acids (linoleic and arachidonic acids, 10(-7)-10(-4) M), cardiolipin (10(-5)-10(-4) M), phosphatidylinositol (10(-5)-10(-4) M), 2.6-ditretbutyl-4-exitoluene (10(-4) M), and argon produced a significant stabilizing effect on naloxone binding. The microviscosity changes in the ESR probe (2,2,6,6-tetramethyl-4-capryloyloxypiperidine-1-oxyl) environment and peroxidase oxidation of membrane lipids during incubation of rat brain membranes were investigated. It was suggested that the main reason for the decrease in the opioid receptor activity is the peroxidation of unsaturated acid lipids in the specific receptor environment and the reduction of the lipid viscosity.

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The total unsaturation of lipids in plasma and erythrocytes of patients with lung carcinoma was studied. It was demonstrated that the level of unsaturation of blood lipids had a definite prognostic significance for patients with malignant tumors. More favourable prognosis for patients with lung carcinoma was connected with a decline of double-bond level and its invariability (or even its reduction) after chemotherapy.

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