[Urinary bladder substitution using combined membrane based on secretions of human mesenchymal stem cells and type I collagen].

Aim: Despite the widespread use of intestinal cystoplasty, urinary bladder substitution remains a challenging problem due to the complexity of operations and the potentially high risk of complications. A promising alternative may be bio-engineered collagen-based matrices containing stem cells or their secretions.

Material And Methods: To evaluate the effectiveness of this bladder substitution modality, an experiment was conducted on 14 male rabbits.

Kinetics of BMP-2 release from collagen carrier: evaluation by enzyme immunoassay in the presence of plasma proteins.

Test system ELISA-BMP-2 is developed for measuring recombinant human bone morphogenetic protein-2 in human and laboratory animal serum and plasma by sandwich ELISA. The test system has been used for studies of the kinetics of bone morphogenetic protein-2 release from collagen carrier in the presence of plasma proteins.

[Regulation of the binding of the BMP-2 growth factor with collagen by blood plasma fibronectin].

The release kinetics of recombinant human bone morphogenic factor 2 (rhBMP-2) from collageneous hydrogel in the presence of human blood plasma have been studied. The expulsion of rhBMP-2 from the collagen-BMP-2 complex by the competitive adhesion of collagen-binding proteins penetrating from plasma was firstly recognized. It was experimentally proven that that blood plasma fibronectin is the main collagen-binding protein, which is responsible for the controlled release of rhBMP-2.

[Computer simulation of hydraulic flows in a human eye].

A two-dimensional computer model was developed to describe hydraulic flows inside the human eye. The flow field was described by coupled Navier-Stokes and Darcy equations. The velocity and pressure profiles in the chambers, the wall, and the vitreous body of the normal eye were obtained using the finite-element method.

[A new Escherichia coli strain producing human tumor necrosis factor].

An Escherichia coli strain producing human tumor necrosis factor (TNF-alpha) was obtained using a semisynthetic gene partially optimized in respect of codon composition and a phage T7 promoter. The expression product was accumulated in cells as inclusion bodies in a yield of 50-70 mg/l of culture medium. The recombinant TNF-alpha in the form of inclusion bodies was used for immunization of rats to give a polyclonal antiserum.

[Autoantibodies Against beta(1)-Adrenoreceptors in Patients With Cardiac Rhythm Disorders. Prevalence and Possible Role in Development of Arrhythmia].

Aim: To assess prevalence of autoantibodies against beta(1)-adrenoreceptors (beta(1)-AR) in patients with arrhythmias of various etiology.

Material: Patients with arrhythmias (n=110, including 59 patients with primary [idiopathic] electrical abnormalities, 33 - with chronic myocarditis and dilated cardiomyopathy [DCM]; 18 - with ischemic heart disease [IHD]) and healthy control subjects (n=20).

Methods: Antibodies against beta(1)-AR were measured in blood serum by direct immunoassay.

[Concentration-dependent effects of magnetic accumulation of ligand-binding microparticles and ferritin aggregates].

A method for measuring the magnetic susceptibility of microparticles of a suspension from the thickness of the layer deposited on the surface of a magnetized wire was developed. The magnetic accumulation was registered by means of a photodetector, by measuring the amplitude and spectrum of fluctuations of the intensity of scattered light. This was used as the basis for the development of a biosensor and biochips.

[Treatment of surface burns with proteolytic enzymes: mathematic description of lysis kinetics].

The lysis of necrotic tissue by a proteolytic enzyme applied to the surface of a burn wound was studied. A mathematical model was proposed, which describes changes in the thickness of necrotic tissue as a function of the proteolytic activity of the enzyme. The model takes into account the inward-directed diffusion of the enzyme, the counterflow of interstitial fluid (exudates) containing specific inhibitors, and the extracellular matrix proteolysis.

Structure of C-reactive protein excreted in urine during acute rejection episodes.

During acute rejection of renal allografts C-reactive protein is excreted in urine in a monomeric form. We developed an immunochemical method for detecting monomeric C-reactive protein in human physiological fluids, which is based on latex agglutination.

[Treatment of burn surfaces by proteinases: mathematical description of an enzyme distribution].

The process of penetration of a proteolytic enzyme applied to the surface of burn wound into the depth of necrotic tissue was considered. The model approximation describes three factors by a series of mathematical equations: inward-directed enzyme diffusion, counter-flow filtration of interstitial fluid (exudates), and irreversible inactivation of the enzyme by specific inhibitors present in exudates. According to the model, a quasi-stationary distribution of enzymatic activity through the thickness of the necrotic layer is achieved within 3 h and persists as long as the enzyme concentration on the wound surface is constant.

Hemophilia A and B are associated with abnormal spatial dynamics of clot growth.

To gain greater insight into the nature of the bleeding tendency in hemophilia, we compared the spatial dynamics of clotting in platelet-free plasma from healthy donors and from patients with severe hemophilia A or B (factor VIII:C or IX:C<1%). Clotting was initiated via the intrinsic or extrinsic pathway in a thin layer of nonstirred plasma by bringing it in contact with the glass or fibroblast monolayer surface. The results suggest that clot growth is a process consisting of two distinct phases, initiation and elongation.

Urokinase plasminogen activator augments cell proliferation and neointima formation in injured arteries via proteolytic mechanisms.

Urokinase plasminogen activator (uPA) has been implicated in the healing responses of injured arteries, but the importance of its various properties that influence smooth muscle cell (SMC) proliferation and migration in vivo is unclear. We used three recombinant (r-) forms of uPA, which differ markedly in their proteolytic activities and abilities to bind to the uPA receptor (uPAR), to determine, which property most influences the healing responses of balloon catheter injured rat carotid arteries. After injury, uPA and uPAR expression increased markedly throughout the period when medial SMCs were rapidly proliferating and migrating to form the neointima.

[Urokinase stimulates whereas tissue plasminogen activator attenuates blood vessel stenosis].

Periadventitial application of the urokinase-plasminogen activator (uPA) in pluronic gel to an injured artery stimulated the neointima and neoadventitia formation as well as cell migration and proliferation in vivo. In contrast, the tissue-type plasminogen activator (tPA) reduced the number of neointimal smooth muscle cells and neointimal area and attenuated the lumen stenosis after a balloon catheter injury of the rat carotid artery. This ability to stimulate the neointima and neoadbentitia formation was found to be quite specific for the uPA.

[Distribution of recombinant pro-urokinase in the rabbit blocked carotid artery].

Distribution of recombinant pro-urokinase (PRU) in segments of blocked carotid arteries of rabbits was measured in 10, 20 and 30 minutes after i.v. administration of the RPU.

[Urokinase induces adhesion of monocytes to fibrinogen].

Urokinase activates adhesion of monocytic U937 cells to fibrinogen-coated surface. This effect is due to urokinase proteolytic activity and does not depend on the urokinase binding to its receptor.

[Pharmacokinetics of recombinant pro-urokinase ocular dosage form].

Thrombolytic enzymes are widely used in the treatment of vascular diseases of the eyes and of intraocular hemorrhages. We studied the pharmacokinetics of recombinant prourokinase (proRUK) in ocular structures after its intravitreal administration and subtenon's implantation of collagen infusion system (SICIS). Kinetic parameters of accumulation of labeled proRUK in ocular structures were obtained.

[Effect of growth factors (BFGF and PDGF) on urokinase secretion by smooth muscle cells].

The dependence of urokinase (uPA) secretion on basic fibroblast growth factor (bFGF) and platelet-deprived growth factor (PDGF BB) was investigated by using of cultured rat aortic smooth muscle cells (SMC). Growth factors stimulated secretion of urokinase with two-phase kinetics within 1-60 minutes. Namely, "apparent" concentration of uPA in the conditioned media rised to 12.

[Follow-up of fibrin clot growth in blood plasma].

The authors propose a device for following up the kinetics of the fibrin clot enlargement in the plasma. Coagulation is induced by contact activation with a fragment of an arterial wall put into the plasma. Besides the initial time of clot formation, the device helps assess the rate of clot growth.

[Use of avidin for speedy clearance of biotinylated immunoglobulins from the blood flow].

The phenomenon of a hundredfold more rapid blood clearance of biotinylated immunoglobulins after post-injection of an equiponderate dose of avidin is described. The concentration of 125I-labeled biotinylated IgG in rat circulation slowly decreased to 20% of the initial level in 24 hours. Avidin injection at any moment of this period induced a 90-95% reduction of blood radioactivity in 15 minutes.

[Immunologic mechanisms of the development of nonspecific aortoarteritis].

It has been shown that patients with nonspecific aortoarteritis undergoing acute and subacute stages of the process demonstrate sensitization to collagen, types I and III. The activity of inflammation was discovered to affect the disease progression and involvement of new arterial areas. Marked suppression of leukocyte migration in response to collagen, types I and III, in patients with nonspecific aortoarteritis points to a high probability of further disease progression.

[The role of thrombocyte prostanoids and products secreted by dense granules in the platelet attachment, spreading and aggregation on collagen substrates].

The role of platelet prostanoids and substances released from dense bodies (ADP and serotonin) in the initial attachment, spreading and aggregation of platelets on surfaces coated with I, III, IV and V genetic types of collagen was investigated. A positive linear correlation was found to exist between thrombi-like aggregate formation on collagen substrates and platelet prostanoid synthesis. No correlation was established between platelet aggregate formation and 14C-serotonin release.