[Interaction of C60 fullerene-polyvinylpyrrolidone complex and brain Aß(1-42)-peptide in vitro].

Using a spectrophotometric method changes occurring in solution containing brain Aß(1-42)-peptide, fullerene C60, and polyvinylpyrrolidone were analyzed. Using the Bent-French method relative binding constants of fullerene C60 with Aß(1-42)-peptide and polyvinylpyrrolidone with Aß(1-42)- peptide were determined. These data suggest that Aß(1-42)-peptide interacting with the C60 fullerene-polyvinylpyrrolidone complex partially displaces polyvinylpyrrolidone and generates a new three molecular compound.

[Changes in gene expression and content of titin (connectin) in striated muscles of chronically etihanol-fed rats].

Changes in gene expression and isoform composition of giant sarcomeric protein titin (connectin) in cardiac muscle, as well as changes of its isoform composition in skeletal muscle (m. soleus) of chronically ethanol-fed rats have been studied using real-time RT-PCR and low percentage SDS-gel electrophoresis. The decrease of titin content in examined muscles and the decrease in titin gene expression in myocardium of chronically ethanol-fed rats have been shown. These changes indicate the development of pathologic process.

[Antiamyloid properties of fullerene C60 derivatives].

A comparative estimation of the ability of complexes of fullerene C60 with polyvinylpyrrolidone and fullerene C60 derivatives (the sodium salt of the polycarboxylic derivative of fullerene C60, sodium fullerenolate), has been carried out. The fullerenes destroyed amyloid fibrils of the Abeta(1-42) peptide of the brain and the muscle X-protein. A study of the effect of fullerenes on muscle actin showed that complexes of fullerene C60 with polyvinylpyrrolidone and sodium fullerenolate did not prevent the filament formation of actin, nor did they destroy its filaments in vitro. Conversely, sodium salt of the polycarboxylic derivative of fullerene C60 destroyed actin filaments and prevented their formation. It was concluded that sodium fullerenolate and complexes of fullerene C60 with polyvinylpyrrolidone are the most effective antiamyloid compounds among the fullerenes examined.

[Changes in the composition of cardiac muscle myosin light chains during cardiac diseases].

In this paper our data of the study on composition of human cardiac myosin light chains in norm and its changes at different stages of dilated cardiomyopathy and heart valvular diseases are presented. Functional role and diagnostic value of these changes are discussed.

[Seasonal changes in the isoform composition of the myosin heavy chains in skeletal muscles of hibernating ground squirrels Spermophilus undulatus].

Seasonal changes of the isoform composition of myosin heavy chains in skeletal muscles (m. triceps, m. longissimus dorsi, m. soleus, m. gastrocnemius, m. vastus lateralis) of hibernating ground squirrels Spermophilus undulatus were studied. Functional properties of myosin (the actin-activated ATPase activity and its Ca(2+)-sensitivity in vitro) were also examined. It was observed that the content of slow myosin heavy chain I isoform increased and the content of fast IIx/d isoform decreased in muscles of torpid ground squirrels and animals which are active in autumn and winter. In muscles of these animals the content of N2A-titin isorfom decreased although the relative content of NT-titin isoform, observed in striated muscles of mammals in our previous experimental works, increased. Actin-activated ATPase activity and Ca(2+)-sensitivity of myosin isolated from skeletal muscles of torpid and interbout ground squirrels were found to reduce. The changes observed are discussed in the context of adaptation of skeletal muscles of ground squirrels to hibernation conditions.

[Fluorescence analysis of the action of soluble derivatives of fullerene C60 on amyloid fibrils of the brain peptide Abeta(1-42)].

It has been shown by fluorescence analysis in vitro that the water-soluble sodium salt of the polycarboxylic derivative of fullerene C60, fullerenol, and complexes of fullerene C60 with polyvinylpyrrolidone (mol. wt. 25000 and 10000) destroy amyloid fibrils of the brain peptide Abeta(1-42) and prevent their formation. The results of fluorescence analysis confirmed the data obtained earlier by high-resolution electron microscopy. Fluorescence analysis and electron microscopy are complementary methods for the selection of effective antiamylod drugs.

[Role of light chains of myosin in the regulation of contraction of vertebrate striated muscles].

The data of the study on Ca2+ sensitivity of ATPase activity of myosin from vertebrate striated muscles in the presence of actin and the conditions of its manifestation and disappearance are presented. The role of Ca2+ sensitivity of actin-activated myosin ATPase in the regulation of contraction of vertebrate striated muscles is discussed.

[Expression of titin in the myocardium of spontaneously hypertensive rats during in the course of hypertrophy].

Changes in the expression of N2B- and N2BA-isoforms of titin in the left ventricle of the myocardium of spontaneously hypertensive rats during the development of hypertrophy have been analyzed by the methods of real-time scale polymerase chain reaction and SDS gel electrophoresis. It was shown that, in early development of hypertrophy (15-week-old rats), an increase in the expression of mRNA of the titin gene and a decrease in the content of the protein itself occur. At a later stage of development (26-week-old rats), a decrease in the expression of titin at the level of both mRNA and the protein per se was observed. The results obtained can be used in the development of methods for diagnosing the development of myocardium hypertrophy.

[Effect of vibrostimulation on support zones of rat's feet, and support loading on titin N2A-isoform and T2-fragment in m. soleus under the conditions of simulated microgravity].

Effects of daily 3-hr vibrostimulation of foot support zone and 3 hrs. of usual locomotion on titin N2A-isoform and proteolytic T2-fragment were studied in m. soleus of rats during 7-d suspension. Besides, effects of single one-hour support loading following 7-d weight-deprivation on titin N2A- and T2-forms were also evaluated in the muscle. Relative N2A content in m. soleus of the suspended group was noted to reduce approximately 25% as compared with the group of control. In the meantime, relative T2 content grew 2-3 times. Along with other changes in the muscle apparatus, N2A reduction contributes to the decline of m. soleus contractility in suspended rats, and development of the "hypogravity muscular syndrome" The daily 3-hr vibrostimulation of the foot support zones substantially (almost twice) decreased N2A disintegration with parallel reduction in approximately 1.5 times relative T2 content comparing with the Suspension group. Three hours of locomotion a day during suspension did not appear to decrease the relative N2A content in m. soleus. However, in this group of animals the relative T2 content in m. soleus was twice as high as in the control. Single-time presentation of support load for one hour soon after 7-d suspension resulted in more significant (approximately 30%) reduction in relative N2A content and twofold fall of relative T2 content as compared with m. soleus of the rats in group Suspension. These data attest to the leading role of support stimulation in maintaining the structural and functional properties of the musculoskeletal system, specifically the titin N2A-isoform content in m. soleus of rat deprived of gravitational loading. Besides, it was also shown that tracking changes in titin makes possible to follow the course of hypogravitational muscle syndrome and to evaluate effectiveness of preventive methods.

[Effect of nitroderivatives of fullerene C60 on amyloid fibrils of Abeta(1-42) peptide of the brain and muscle X-protein].

The antiamyloidogenic capacity of water-soluble nitroderivatives of fullerene C60: methyl ester of LN-[(2-nitroglyceryl) fullerenyl] proline, methyl ester of LN-[(2,3-dinitroglyceryl) fullerenyl] proline, and 2 nitroxyethyl ether LN-([2-(nitroxy) ethyl] fullerenyl) proline has been studied in vitro by high-resolution electron microscopy. It was shown that these fullerene C60 nitroderivatives are able to prevent the formation of amyloid fibrils by the brain Abeta(1-42)-peptide and muscle X-protein and to destroy mature fibrils. Electron microscopy is a promising method for selecting effective antiamyloidogenic drugs. The antiamyloidogenic activity of nanodimensional fullerene C60 nitroderivatives offers strong possibilities for creating a new nanotechnology for the therapy of amyloidoses.

[Contractile properties of fibers and cytoskeletal proteins of gerbil's hindlimb muscles after space flight].

The work had the goal to compare the microgravity effects on gerbil's muscles-antagonists, m. soleus and m. tibialis anterior. The animals were exposed in 12-d space microgravity aboard Earth's artificial satellite "Foton-M3". Findings of the analysis of single skinned fibers contractility are 19.7% diminution of the diameter and 21.8% loss of the total contractive force of m. soleus fibers post flight. However, there was no significant difference in calcium sensitivity which agrees with the absence of changes in the relative content of several major cytoskeletal proteins (titin and nebulin ratios to heavy chains of myosin were identical in the flight and control groups) and a slight shifting of the myosin phenotype toward the "fast type" (9%, p < 0.05). These parameters were mostly unaffected by the space flight in m. tibialis anterior. To sum up, the decline of contractility and diminution of gerbil's myofibers after the space flight were less significant as compared with rats and did not impact the sytoskeletal protein ratios.

[Effect of fullerenes C60 on the amyloids of X-protein].

The inhibitory effect of hydrated fullerene C60 (HyFn) and the sodium salt of the fullerene polycarboxylic derivative C60Cl (C6H4CH2COONa)5 on the formation of amyloid fibrils by X-protein in vitro has been studied by electron microscopy. It has been shown that these compounds not only destroyed mature amyloid fibrils but also prevented the formation of new fibrils. This property of fullerenes, nanoparticles, can be used for the development of a novel medicinal nanotechnology in the therapy of amyloidoses.

[Composition of the titin isoforms in muscles in pathology].

An electrophoretic study of changes in the composition of titin isoforms in skeletal and cardiac muscles of human and rat in pathology has been carried out. A more considerable decrease in the content of intact titin isoforms in comparison with the content of N2BA- and N2B-titins in hypertrophic heart of spontaneously hypertensive rats, N2A-titin in back muscle from patients with the "stiff-man syndrome", and in m. soleus of human and rats during the development of "muscle hypogravity syndrome" has been observed. In the last case, the relation between the reduction of titin content in m. soleus and the increase in the time the rats were in conditions of simulated microgravity has been revealed. On electrophoregrams of the left ventricle myocardium of patients with the terminal stage of dilated cardiomyopathy, intact titin and N2BA-titins were absent, and a considerable decrease in the content of N2B-titins has been observed, which could be a consequence of the terminal stage of pathology. Our results show that the development of the diseases is accompanied by a greater destruction of intact titin than of its other forms, which may be important for diagnostics of the pathological process.

[Seasonal changes in the composition of the titin isoforms in muscles of hibernating ground squirrels].

An electrophoretic study of changes in the content of intact titin isoforms, N2B-, N2BA-, N2A-titins and T2 in skeletal and cardiac muscles of ground squirrel (Spermophillus undulatus) in different periods: summer activity, autumn activity, hibernation, arousal, and winter activity has been carried out. In atriums and ventricles of autumn activity ground squirrels, an increase (approximately 1.5 times) in the N2BA-to-N2B ratio in comparison with that in cardiac muscle of summer activity ground squirrels has been observed. During hibernation, the decrease in the relative content of N2B,- N2BA-titins and T2 in cardiac muscle and of N2A-titin and T2 in skeletal muscles has been tested against the background of preservation of the relative amount of intact titin isoforms. During arousal of ground squirrel and in short-time period of winter activity, a rapid restoration in the content of N2B,- N2BA-, N2A-titins and T2 in muscles has been observed. In this case, in cardiac muscle of hibernating, arousing and winter active ground squirrels, the increased N2BA-to-N2B ratio has been preserved. The changes in the titin content are discussed in the context of adaptation of ground squirrels to hibernation.

[Contractile properties of the isolated rat musculus soleus and single skinned soleus fibers at the early stage of gravitational unloading: facts and hypotheses].

The contractile properties of the postural rat soleus muscle at the early stage of the gravitational unloading (3-day rat hindlimb suspension) have been studied using different modes of muscle contraction (twitch and tetanic contraction of the isolated muscle, Ca-induced contraction of isolated skinned fibers). A significant enhancement of the twitch maximal tension of unloaded muscles without changes in time-dependent characteristics was observed, although the half-relaxation time tended to increase. The fiber diameter did not change (42.37 +/- 0.76 vs 43.43 +/- 1.15 microm in controls). The Ca-induced maximal isometric tension in unloaded soleus was significantly decreased (32.1 +/- 1.05 vs 37.6 +/- 1.52 mg in controls, p < 0.05). The maximal specific tension was respectively decreased (23.14 +/- 0.77 vs 27.6 +/- 2.36 kN/m in controls). The pCa50 in unloaded muscle decreased from 6.05 +/- 0.02 in controls to 5.97 +/- 0.02 (p < 0.05), indicating the loss of myofibrillar calcium sensitivity. The analysis with the calcium probe Fluo-4AM demonstrated that the intracellular [Ca2+] was sufficiently increased after hindlimb suspension. At the same time, the relative content of titin and nebulin did not change.

[Autoantibodies to light myosin chains as an early marker of damage to the myocardium].

The concentration of autoantibodies to myosin light chains in the blood serum of patients who have undergone operation on heart under conditions of artificial hypothermal circulation was measured after 3, 6, 9, 18, 24, 36 h following the reperfusion of myocardium. According to the postoperative data, the patients were divided into three groups: patients with stable hemodynamics in the postoperative period (group 1); patients with myocardial stunning following reperfusion of myocardium (group 2); and patients with severe heart failure that developed in early postoperative period (group 3). Significant differences in the concentration of autoantibodies to myosin light chains have been found between the groups. A high correlation was established between the duration of cross-clamping of aorta and the concentration of autoantibodies. By means of multivariant regression analysis, factors characterizing the initial severity of disease that can influence the concentration of autoantibodies to myosin light chains in blood have been revealed.

[Structure and functions of titin, a giant protein of skeletal and cardiac muscles: evidence and suppositions].

The structural and functional properties of skeletal and cardiac titin are described according to the recent experimental evidence and suppositions.

[Electron microscopic study of the influence of fullerene on the formation of amyloid fibrils by A beta(25-35) peptide].

The anti-amyloidogenic capacity of hydrated fullerene C60 HyFn was revealed by the use of electron microscopy. We first showed that when, connecting with growing amyloid fibrils formed by A beta(25-35)-peptide, fullerene prevented their subsequent growth and interfered with the formation of new fibrils. Instead of long helically twisted ribbons formed by A beta(25-35)-peptide in the absence of fullerene, short narrow protofibrils were found in the presence of fullerene . These results allow one to suppose that fullerene can be useful for the therapy of Alzheimer's disease.

[Cytotoxicity of amyloid fibrils of X-protein].

It is known that amyloid oligomers, protofibrils, and fibrils induce cell death, and antibiotic tetracycline inhibits the fibrillization of beta amyloid peptides and other amyloidogenic proteins and disassembles their pre-formed fibrils. Earlier we have demonstrated that sarcomeric cytoskeletal proteins of the titin family (X-, C-, and H-proteins) are capable to form in vitro amyloid fibrils, and tetracycline effectively destroys these fibrils. Here we show that the viability of polymorphonuclear leukocytes in the presence of X-protein amyloids depends on the concentration of amyloid fibrils of X-protein and the time of incubation. In addition to the disaggregation of X-protein fibrils, tetracycline eliminated the cytotoxic effect of the protein. The antibiotic itself did not show a toxic effect, and the cell viability in its presence even increased. Our results evidence the potential of this approach for evaluating the effectiveness of drugs preventing or treating amyloidoses.

[The C-terminal fragment of thymopoietin forms F-actin bundles: electron microscopic data].

It was shown by electron microscopy that PEP33 a synthetic C-terminal peptide of the thymus hormone thymopoietin, formed bundles of actin 'filaments in the presence of 0.1 M KCl. The structure of PEP33 aggregates localizated in the bundles between actin filaments is very similar to that of aggregates observed in samples of pure PEP33. No changes were revealed in the structure of G-actin in the presence of PEP33. A similar, but a weaker bundling effect of thymopentin (PEP5) was also found. It forms bundles of actin filaments of small size. Further studies can shed light on the physiological importance of actin filament aggregation with the peptides of thymopoietin, the systematic release of which from the thymus produces the phenomena characteristic for the serious neuromuscular disease myasthenia gravis.