[Segmentary venous hypervolemia as one of the main factors of the patho-hemodynamic development and progression of chronic venous insufficiency of lower extremities in patients with varicose disease ]. / Segmentarnaia venoznaia gipervolemiia kak odin iz osnovnykh patogemodinamicheskikh faktorov razvitiia i progressirovaniia khronicheskoi venoznoi nedostatochnosti nizhnikh konechnostei u patsientov s varikoznoi bolezn'iu.

Phlebographic examinations carried out in 91 patients with varicosity and 30 healthy subjects have determined structural peculiarities of the intramuscular shin veins in health and disease. A comparison of the anatomical findings with the degree of hemodynamic abnormalities allowed to make a conclusion that intramuscular segmental hypervolemia should be considered as one of the main pathogenic links in the pathophysiological chain of the development of chronic venous insufficiency. Further elevation of supravalvate venous segmental actazia forms a relative valve incompetence at the particular level which promotes the spreading of retrograde pathological blood flow in distal direction. Blood shunting into the intramuscular shin veins is one of the compensatory mechanisms of increasing pathological hypervolemia as a cause of valve incompetence and retrograde blood flow. The procedure of evacuation from the skin veins directly depends on the effective work of the shin muscular-venous pump. Further involvement of the intramuscular veins in the pathological process, the low effectiveness of the shin muscular-venous pump results in greater dysfunction and finally forms a hypodynamic vicious circle of chronic venous insufficiency with all its manifestations.

[Complications of implantation of the cava filter "Réptéla"]. / Oslozhneniia pri implantatsii kava-fil'tra "REPTELA".

The article describes a complication resulting from the implantation of a cava-filter for roentgen endovascular prophylactics of thromboembolism of the pulmonary artery (REPTEPA) to a 68 years old woman with recurring thromboembolism of the pulmonary artery, floating thrombus of the right iliac vein. An attempt to disconnect the cava-filter from the applicator after implantation proved to be unsuccessful which was followed by urgent operation: marginal resection of the vena cava inferior with the cava-filter, suture of the vein, cava plication. The nearest postoperative period was complicated by thrombosis of the plication zone. The examination in 6 months has shown the formation of the syndrome of the vena cava inferior.

Ribonuclease-P RNA gene of the plastid chromosome from Cyanophora paradoxa.

The gene, rnpB, encoding the RNA portion of ribonuclease-P has been found in the cyanelle DNA of Cyanophora paradoxa. A secondary structure model for the cyanelle RNA fits into that for eubacterial Rapb-RNAs.

[Role of radiologic diagnosis in the evaluation of morphologic and functional changes in muscular veins of the leg in the pathogenesis of varicose disease]. / Rol rentgenomorfologicheskikh i funktsionalnykh izmenenii myshechnykh ven goleni v patogeneze varikoznoi bolezni.

A total of 100 patients with varicosis of lower limb veins were investigated with the help of distal ascending phlebography in horizontal, vertical and tilted positions. Considerable differences in x-ray images of musculi gastrocnemius and soleus (MGS) were noted. Four main types of MGS (conic, spindle-form, U-form, and balloon-like) were singled out. Correlation between muscular vein sizes and stages of varicosis was revealed. An important role of the pathology of muscular veins in dysfunction of the leg pump as one of the factors of pathogenesis of lower limb varicosis was confirmed.

[Reconstructive surgery of valvular incompetence of deep veins in patients with varicosity of the lower limbs]. / Rekonstruktivnaia khirurgiia klapannoi nedostatochnosti glubokikh ven u bol'nykh varikoznoi bolezn'iu nizhnikh konechnostei.

The individual indications for applying four methods for valve correction in 241 patients with valvular incompetence of the deep veins were determined on the basis of a developed four-stage organization-diagnostic complex. The methods were as follows: correction with a lavsan spiral (70 operations), suturing with paravasal structures (59), three-ligature method (142), and an original method with shortening of the cusps without opening the vein (30 operations). Study of the late results in follow-up periods of 12 months to 7 years showed the latter method to be most effective (88.2%).

[Surgical correction of valvular insufficiency of deep varicose veins of the lower extremities]. / Khirurgicheskaia korrektsiia nedostatochnosti klapanov glubokikh ven nizhnikh konechnostei pri varikoznoi bolezni.

A scheme for preoperative examination of the patients with varicose disease is presented. Incompetence of the deep venous valves was revealed in 74.1% of the patients with varicose disease and in 76.5%--with its postoperative recurrences. Correction of ++phlebo-hemodynamics was accomplished by means of a carcass spiral, fascial paravasal structures and suggested by the authors method of placing the three corrective ligatures, which has proved to be the most effective. One hundred and forty two operations on the deep veins were performed in 102 patients. In observation for up to 4 years, in 94.7% the excellent and good results were noted.

[Evaluation of changes in the deep veins of the lower limbs in varices]. / Otsenka izmenenii glubokikh ven nizhnykh konechnostei pri varikoznoi bolezni.

The authors analysed the results of studying disorders of the deep veins of the lower limbs in 106 patients with varicosity, who were examined by means of distal ascending and retrograde femoral and popliteal phlebography. Ectasia of the deep veins was revealed in 97 (91.5%) and valvular incompetence--in 89 (84%) patients. The authors elaborated a phlebographic evaluation of the degree of ectasia and a classification of valvular incompetence according to the manifestation of the retrograde blood flow in them, which is necessary for a differentiated approach to the surgical correction of these disorders.

[The key role of fructose-2,6-bis-phosphate in the temporal organization of carbohydrate metabolism. An auto-oscillating mathematical model]. / Kliuchevaia rol' fruktozo-2,6-bis-fosfata vo vremennoi organizatsii uglevodnogo obmena. Avtokolebatel'naia matematicheskaia model'.

A mathematical model describing the periodical temporal organization of the open futile cycle fructose-6-phosphate in equilibrium fructose-1,6-bisphosphate (F6P in equilibrium F1,6P2) is investigated. The oscillations in this cycle are caused by the regulatory cycle F6P in equilibrium fructise-2,6-bisphosphate (F2,6P2), catalyzed by phosphofructokinase-2 (PFK-2) with a cascade of covalent chemical modification. The apparent product activation of PFK-2 by F2,6P2 together with the F2,6P2 outflux from the regulatory cycle create square-shaped oscillations in the concentration of F2,6P2, a powerful reciprocal regulator of the enzymes of the futile cycle F6P in equilibrium F1,6P2. Compared to the mechanisms of the autonomous regulation of the F6P in equilibrium F1,6P2 cycle suggested previously, the new one provides an excellent temporal separation of the glycolytic and gluconeogenic pathways and possesses a considerably larger region of existence of the self-oscillatory behaviour.

[Oscillations and trigger phenomena in fructose-2,6-bis-phosphate metabolism. A mathematical model]. / Kolebaniia i triggernye iavleniia v obmene fruktozo-2,6-bis-fosfata. Matematicheskaia model'.

A mathematical model describing metabolism of fructose-2,6-bisphosphate (F2, 6P2), which is a powerful mediator in glycolysis, is investigated. The model takes into account inhibitory effect of F2, 6P2 and fructose-6-phosphate (F6P) on protein kinase, which phosphorylates the bifunctional enzyme fructose-6-phosphate-2-kinase/fructose-2,6-bisphosphatase. Such a mechanism of enzyme chemical modification in the presence of F2, 6P outflow from the F6P in equilibrium with F2, 6P2 cycle, caused by nonspecific phosphatases, can display trigger phenomena and sustained oscillations in F2, 6P2 metabolism and in the whole glycolytic system. The results obtained suggest that earlier models of the generation of glycolytic oscillations should be revised.

[Kinetic manifestations of slow conformation rearrangements of lactate dehydrogenase. An experiment and a mathematical model]. / Issledovanie kineticheskikh proiavlenii medlennykh konformatsionnykh perestroek v laktatdegidrogenaze. Eksperiment i matematicheskaia model'.

Non-steady-state kinetics of lactate dehydrogenase (LDH) catalyzed reaction was investigated for a wide time interval (from 100 msec to 1-3 min) by using stopped-flow methods. A two-stage character of LDH reaction, slow changes like a lag-period on kinetic curves at pH 8.0, flexions on kinetic curves after pre-mixing LDH with NAD+ and pyruvate have been revealed. The graph theory for mathematical analysis of experimental data was applied, which has been developed for the non-steady-state kinetics. An enzyme model of the two-conformer LDH structure was used. The reaction scheme with a preferential inhibition of one of the conformers (pH 8.0) is suggested. The obtained values of kinetic constants prove that transitions between LDH conformers must be slow.

Stability of multienzyme systems with feedback regulation: a graph theoretical approach.

Stability of multienzyme systems with feedback regulation has been analyzed on the basis of the Lienard-Chipart criteria. The rules governing the topological graph construction for multienzyme systems have been developed. A theorem about correspondence of the graph constructed and coefficients of the characteristic polynomial of linearized kinetic equations is proved. The graph-theoretical stability analysis proposed is illustrated by a number of examples of multienzyme systems with feedback regulation.

[A model of oligomeric enzymes explaining stepwise kinetic curves]. / Model' oligomernykh fermentov, ob''iasniaiushchaia "stupenchatye" kineticheskie krivye.

The complex kinetics of some oligomeric enzymes has been analysed. For interpreting such kinetics a theoretical model of an oligomeric enzyme is suggested, which is a modification of the "flip-flop" mechanism considered by Lazdunski et al. in 1971. Using our model, one can qualitatively interpret stepwise kinetic curves, i.e. the curves with few intermediate plateaus. Such curves are known from literature but have not exhaustively been explained. It is supposed that the enzyme kinetic curves can sometimes be of non-differential functions. The model used can also be applied to the kinetics of polyenzyme complexes.