[Isolation and characteristics of fibronectin from fibrinolytically active human plasma]. / Vydelenie i kharakteristika fibronektina iz fibrinoliticheski aktivnoi plazmy krovi cheloveka.

Properties of fibronectin, isolated by means of affinity chromatography from blood plasma of suddenly dead persons, were studied. This blood exhibited high fibrinolytic potential and was not capable of clotting due to degradation of fibrinogen. At the same time, fibronectin was also isolated from blood plasma of healthy volunteers. Properties of these fibronectins of dissimilar origin were studied using the following parameters: content of immunoreactive and bioreactive fibronectin in blood plasma, affinity towards gelatin, yield of fibronectin from blood plasma, molecular mass, heterogeneity. Both these fibronectins from different sources of blood plasma were similar in their properties studied, thus demonstrating that any significant degradation of fibronectin did not occur in hyperfibrinolysis in vivo.

[Quantitative and qualitative changes in the fibronectin level in rheumatoid arthritis]. / Kolichestvennye i kachestvennye izmeneniia fibronektina pri revmatoidnom artrite.

Blood plasma and synovial fluid (SF) of 48 patients with rheumatoid arthritis (RA) were studied. Plasma fibronectin (FN) concentration measured by rocket immunoelectrophoresis was found to be almost the same in patients and in healthy donors (348.6 +/- 16.4 micrograms/ml and 354.3 +/- 10.2 micrograms/ml, respectively. The level of SL FN was shown to rise in RA patients up to 1069.7 +/- 157.2 micrograms/ml, whereas in healthy persons and in posttraumatic synovitis it was equal to 420.0 +/- 112.6 micrograms/ml (p less than 0.05). Using cross-immunoelectrophoresis, the heterogeneity of synovial FN was revealed which was determined by complex formation with hyaluronic acid. It was found that both plasma and synovial fluid possessed higher gelatin-binding activity when compared with control samples as studied by the ability to agglutinate gelatinized particles. Direct correlation was shown between disease development rate and bioassayable plasma and synovial fibronectin.

[Complex-formation with hyaluronic acid as a cause of fibronectin heterogeneity in the synovial fluid]. / Kompleksoobrazovanie s gialuronovoi kislotoi kak prichina geterogennosti fibronektina v sinovial'noi zhidkosti.

Heterogeneity of synovial fluid fibronectin was studied by means of Laurell cross-immunoelectrophoresis in patients with rheumatoid arthritis, posttraumatic synovitis and other arthropathies. Prior to hyaluronidase treatment all the synovial fluid samples exhibited the fibronectin heterogeneity, which disappeared after the action of hyaluronidase. The data obtained suggest that complexes of fibronectin and hyaluronic acid are responsible for physico-chemical heterogeneity of fibronectin in synovial fluid.

[Effect of thyroidectomy on the histochemical and electrophysiological properties of the soleus muscle in rats]. / Vliianie tireoidéktomii na gistokhimicheskie i élektrofiziologiches-kie svoistva kambalovidnoi myshtsy krysy.

In the musculus soleus of mature male rats, 6 weeks after thyroidectomy, muscle fibers with a low adenosin triphosphatase activity of myosin decrease in number, as well as the cross section area of the muscle fibers with a moderate and high activity of the enzyme. Optic density of the muscle fibers staining also decreases when succinatedehydrogenase activity is determined histochemically. There is no change in the rest membrane potential and in the character of the muscle fiber membrane sensitivity to acetylcholine. The change in the muscle fiber histochemical properties is combined with chromatolysis in the motor neurons of the spinal cord ventral horns.

[Histo- and biochemical characteristics of rat skeletal muscle after prolonged static loading]. / Gisto- i biokhimicheskaia kharakteristika skeletnykh myshts krys posle dlitel'noi staticheskoi nagruzki.

For 100 days the rats were kept in vertical position, and after histo- and biochemical characteristics of the musc. gastrocnemius (fast) and musc. soleus (slow) were studied. A prolonged static loading was stated to produce increasing number of white and intermediate fibres in the m. gastrocnemius and intermediate fibres in the m. soleus. The fast and slow muscles reacted differently to the static loading; this was evident from a decreased content of glycogen in muscle fibers. A statistically important decrease in lactate dehydrogenase (LDH) activity in blood serum and the m. gastrocnemius was found, while in the m. soleus its level remained unchanged. It was found for certain that lactic acid content increased in the muscles studied, and its content did not change in blood serum. As to pyruvic acid content, it increased in blood serum, decreased in the m, gastrocnemius and did not differ from the control in the m. soleus. In the m. gastrocnemius an increased activity of slowly migrating LDH isoenzymes was noted, while in the m. soleus--that of fast migrating ones. At a prolonged static loading there was normalization in histo- and biochemical characteristics as it is at the dynamic loading.

[Ultrastructure of rat skeletal muscle fibers during prolonged static loading]. / Ul'trastruktura skeletnykh myshechnykh volokon krys pri dlitel'noi staticheskoi nagruzke.

Ultrastructural characteristics of the rat skeletal muscle fibers was studied under a prolonged static loading. Disruption of the mitochondrial membranes, desintegration and lysis of myofibrils, desorganization of the T-system and Z-bands were revealed. Destructive processes were accompanied with the physiological reparative regeneration evidenced by a large number of polysomes and accumulation of myofibrils at the peripheral zone of the muscle fibre. The satellite cells with poorly developed organells were revealed in cytoplasm. Mitotic figures were present in the satellite cells. Clusters of the satellite cells were revealed in the interstitial connective tissue with their successive differentiation into mature muscle fibres. Possible mechanisms of the skeletal muscle fibre formation were discussed.

[Morphologic and morphometric characteristics of rat skeletal muscles following prolonged static loading]. / Morfologicheskaia i morfometricheskaia kharakteristika skeletnykh myshts krys posle dlitel'noistaticheskoi nagruzki.

Musculus gastrocnemius and m. soleus in Wistar rats have been studied at a prolonged static loading. The static loading does not produce any changes in the animals' body mass and in m. gastrocnemius, while the mass of m. soleus statistically differs after the experiment. There are some changes in relative amount of muscle fibres: in m. gastrocnemius the number of white muscle fibres increases, and the number of red muscle fibres decreases, in m. soleus the number of intermediate muscle fibres increases. In m. gastrocnemius of the test animals the transversal section areas of white and intermediate muscle fibres statistically decrease, and in m. soleus the transversal section areas of both muscle fibre types increase. Examination of semi-thin and celloidin sections demonstrate fibre-targets, fibres with centrally situated nuclei, partly splitting fibres and fibres of small diameter, their number reaching 4.3% of the whole number of fibres. Possible mechanisms for muscle fibre formation are discussed.