Biomedical subjects
Publications and source records attributed to S V Smirnov.
Improvement of methods for culturing skin cells stimulates their wide application in the treatment of a variety of skin injuries. A method for restoration of the skin with cultured epithelium and cultured epithelium in combination with a derma analog (collagen gel with fibroblasts) was developed. Possible mechanisms for skin repair after transplantation of cultured allogenic skin transplants were analyzed.
Registered in patients with burn trauma was the presence of endogenous intoxication (EI), which was determined by a higher value of coefficient CLP/AOS, a higher contents of medium-molecular peptides (MMP), a lower total and effective concentration of albumin (TAC and EAC) and by a reserve of the binding albumin ability. Intoxication coefficients, i.e. IC MMP/EAC and IC C/EAC showing the deposition and binding of toxic ligands, were acknowledged as the most informative EI parameters.
Complex of methods for repair of wounded and burned skin with transplantation of keratinocytes and fibroblasts grown in vitro is proposed. Five different tissue constructions may be used. Original method of skin recovery based on use of alive equivalent of skin is developed. Results of its clinical application are presented. It is concluded that cell constructions may be used in combined treatment of wounds and burns.
Clinical and laboratory evaluation of pectins application efficacy demonstrated that the patients treated with pectines has lower frequency of bacteriemia, intoxication, infectious complications and lethality. Pectins use per os resulted by acceleration of burns wounds healing and by lower microbial dissemination. Frequency of coagulase-positive staphylococci, streptococci and enterococci isolation was also lower in the treated group of patients when compared to the control group. Feces microbial profile also demonstrated positive trend--normal microflora (bifidobacteria and lactobacilli) enhanced, opportunistic bacteria diminished. Pectins application provided normalization of leucocytes, lymphocytes, B-lymphocytes, immunoglobulins A and G. The results of investigation demonstrated pectins efficacy at the complex treatment regimes of the patients with burns.
The results of the burned wounds treatment with 1-2% solution of apple or beet pectins were analysed. The control results were examined at the same patients with symmetrical wounds treated by chlorhexidine, levomecol, furacillin liniment. Clinical evaluation demonstrated good tolerability of the treatment regime, absence of side effects and complications, inhibition of inflammation, acceleration of epithelisation of the burns II-IIIA class, allowed to diminish the preliminary period before autodermoplastic operation (burns of IIIB class), diminished microbial dissemination and dissemination with Pseudomonas aeruginosa. The best results were demonstrated when the pectins application was performed since the first day after the burned injury.
NSO/1 (P3x63Ay 8Ut) and SP20 myeloma cells were inoculated to BALB/c OlaHsd mice. NSO/1 cells allowed adequate stage-by-stage monitoring of tumor development. The adequacy of this model was confirmed in experiments with conventional cytostatics: prospidium and cytarabine caused necrosis of tumor cells and reduced animal mortality.
Results of clinical and laboratory evaluation of the treatment with pyobacteriophage in tablets of the patients with burn wounds are presented. It was shown that phagotherapy provided more rapid cure of pyoseptic complications, temperature normalization, wounds purification and lower lethality Bacteriological analysis of wound secretions revealed that after the treatment staphylococci and streptococci were cultured 2 times rarely, Proteus spp. Were isolated 1.5 times rarely, E. coli was not isolated. The amount of positive haemocultures also diminished. Investigation of immunologic status demonstrated statistically significant normalization of immunity on cell level. Phagocytosis level didn't change while in control group (without bacteriophage use) it became lower. Antibody level enhanced but less extensively than in control group. The results of trial demonstrates positive effect of phagotherapy use at the patients with burns.
Acute erosive ulcerative hemorrhage (EUH) is one of the most grave complications of burn disease, caused by impaired blood rheology, clotting, and protein status. Twenty-three patients with burns of 12-70% body surface were examined, 17-25% of burns being deep. The most pronounced changes in blood rheology and clotting with formation of erythrocyte aggregations, fibrin precipitation and imbalance of visceral proteins were observed during the shock stage (days 1-3), particularly pronounced in patients with acute EUH. Development of septicotoxemia favored secondary increase in blood clotting and rheological parameters, which led to thrombotic complications. The data helped improve the complex of infusion-transfusion therapy for preventing and treating ulcerative and erosive lesions.
Extracellular pH (pH(o)) influences vasoconstriction partly by modulating Ca(2+) influx through voltage-gated Ca(2+) channels in the vasculature. The mechanism of this effect of pH(o) is, however, controversial. Using the whole cell voltage-clamp technique, we examined the influence of pH(o) on L-type Ca(2+) channel currents in isolated human mesenteric arterial myocytes. Acidification to pH 6.2 and alkalinization to 8.2 from 7.2 decreased by approximately 50% and increased by 25-30%, respectively, the peak amplitude of Ca(2+) and Ba(2+) currents (1.5 and 10 mM), with an apparent pK(a) of 6.8. Activation and inactivation of Ca(2+) and Ba(2+) currents were shifted toward positive membrane voltages during acidification and in the opposite direction during alkalinization. The relationship between the current amplitude and shifts in the gating parameters in solutions of different pH(o) conformed closely to that predicted by the Gouy-Chapman model, in which the divalent cation concentration at the outer surface of the membrane varies with the extent to which protons neutralize the membrane surface potential.
Thirty-five patients (aged 45 +/- 2.0 years) with isolated inhalation injury were examined on days 1, 3, and 7 after the injury, Serum concentrations of lipid peroxidation (LPO) products (dienic conjugates, malonic dialdehyde, and degree of lipid oxidation) were increased in all terms of investigation. Studies of the antioxidant system (AOS) showed a decrease in endogenous alpha-tocopherol during all terms, while ceruloplasmin content gradually increased. LPO/AOS imbalance was the most expressed on day 7 after the injury, which indicates intensification of LPO processes in the victims. The results pathogenetically validate the use of antioxidants in combined therapy of patients with inhalation injuries. LPO/AOS imbalance should be evaluated in these patients.
1. Voltage-gated K+ currents in human myometrium are not well characterized, and were therefore investigated, using the whole-cell patch clamp technique, in freshly isolated myometrial smooth muscle cells from pregnant women at term. 2. Three types of voltage-gated K+ currents were identified. IK1 was a 4-aminopyridine-insensitive current with a negative half-inactivation (V0.5 = -61 to -67 mV) and negative activation characteristics (threshold between -60 and -40 mV) and slow kinetics. IK2 was a 4-aminopyridine-sensitive current (half-maximal block at approximately 1 mM) with relatively positive half-inactivation (V0.5 = -30 mV) and activation characteristics (threshold between -40 and -30 mV) and faster kinetics. IK,A was a 4-aminopyridine-sensitive current with a negative inactivation and very fast inactivation kinetics. 3. Both IK1 and IK2 were sensitive to high concentrations of tetraethylammonium (half-maximal block at approximately 3 mM) and low concentrations of clofilium (half-maximal block by 3-10 microM). 4. IK1 and IK2 were unevenly distributed between myometrial cells, most cells possessing either IK1 (30 cells) or IK2 (24 cells) as the predominant current. 5. The characteristics of these currents suggest a possible function in the control of membrane potentials and smooth muscle quiescence in the pregnant human myometrium.
An efficient method for isolation of virus mutants with antigenically altered proteins is described. The method is based on the separation of viruses with wild-type and antigenically altered proteins by affinity chromatography using monoclonal antibodies (MAbs). A nonessential glycoprotein E (gE) of Aujeszky's disease virus (ADV) was chosen as a model for introducing the antigenic changes. The ADV strain Ka mutagenised with 5-bromo-2'-deoxyuridine was used for the selection of mutants that do not bind to gE-specific MAb conjugated to resin. After three rounds of isolation by affinity chromatography, the resulting viruses that escape the binding to MAb were plaque-purified by plating at limiting dilution, and virus isolates were tested by the gE-specific sandwich ELISA in which the selecting MAb was used as a capture antibody. About 70% of the ADV isolates tested were not recognised by the sandwich gE-ELISA. The analysis of some of virus isolates in indirect ELISA with a panel of 16 gE-specific MAbs revealed that at least several of the generated virus isolates were mutants expressing gE with alterations in the epitope of the selecting MAb 75/7, as well as in the majority of other conformation-dependent epitopes of gE. The method for the production of antigenically altered viruses by affinity chromatography using MAbs is simple and convenient, and can be utilised with MAbs irrespective of their virus-neutralising activity.
Expression plasmids containing the synthetic gene hil-4 delta 2 was constructed to produce human interleukin-4 in Escherichia coli cells. Strains TG1 (pBTIL-4 delta 2) and BL21 (DE3) (pETIL-4 delta 2) produced the recombinant protein as inclusion bodies, and its production level was up to 30% of the total cell protein. The renatured hIL-4 delta 2 inhibited IL-4-stimulated T cell proliferation, and this effect was enhanced by cyclosporin A.
Albumin is the major plasma protein circulating in blood. Albumin potently decreases capillary permeability, although the mechanisms are not understood completely. Albumin also effectively binds arachidonic acid (AA), which increases capillary permeability. To investigate the interactions of BSA and AA with the cell membrane, the effect of these substances on [3H]AA release and membrane fluidity was studied in vascular myocytes and endothelial cells. BSA (0.2 and 1 mg . mL-1) stimulated a significant release of [3H]AA from both intact rat aorta and cultured smooth muscle cells. This effect was not mimicked by gamma-globulin or myoglobin (both 1 mg . mL-1) in intact tissue. BSA, but not gamma-globulin and myoglobin, decreased the membrane fluidity (assessed as changes in the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3, 5-hexatriene) in a concentration-dependent manner with a half-maximum concentration between 0.007 and 0.4 mg . mL-1 in both freshly isolated and cultured rat aortic myocytes and human umbilical vein endothelial cells. AA (1 to 200 micromol/L) caused the opposite effect, increasing membrane fluidity and antagonizing the effect of BSA. BSA modified at its arginine residues, which are thought to be important in AA binding, did not stimulate [3H]AA release and was significantly less potent than native BSA in altering the membrane fluidity. The effect of BSA can be explained by a high-affinity binding of AA to the protein and extraction of AA from the cell membrane. The interaction between BSA and AA could play a role in the regulation of vascular permeability.
Inhibition of the L-type Ca2+ channel current (IBa) by diltiazem was characterised in human mesenteric arterial myocytes. External (pHo) and internal (pHi) pH was varied to alter the proportion of drug in charged and neutral forms. Diltiazem (20 microM) reduced IBa amplitude by approximately half at pHo 7.2 and 9.2 at holding potential -60 mV. The IBa decay was increased by diltiazem at pHo = 9.2 (97% uncharged), but not at 7.2. The IC50 for inhibition of IBa by diltiazem at holding potential -60 mV was decreased from 51 to 20 microM at pHo 7.2 and 9.2, respectively. At holding potential of -90 mV, but not -60 mV, tonic block increased and use-dependent block decreased as pHo was raised from 6.2 to 9.2. Diltiazem also caused a hyperpolarizing shift in IBa availability at alkaline pHo. The results suggest that raising pH promotes Ca2+ channel blockade by increasing the proportion of uncharged diltiazem.
1. The effects on the voltage-gated (IK) and Ca2+ activated (I(K,Ca)) K+ currents in rat arterial myocytes of the 5-lipoxygenase activating protein (FLAP) inhibitor MK886, and its inactive analogue L583,916 were evaluated. 2. In rat pulmonary arterial myocytes (RPAMs), MK886 caused a concentration-dependent reduction of the IK, with little obvious change in the kinetics of the current. Half maximal current block was observed at 75 nM MK886. 3. MK886 application led to a concentration-dependent increase in the amplitude of the TEA-sensitive I(K,Ca) current and single channel activity in RPAMs in whole cell and inside-out configurations, respectively. The threshold concentration for this effect was approximately 300 nM and a maximal 4-5 fold increase was observed at 10 microM MK886. MK886 also increased I(K,Ca) in rat mesenteric arterial myocytes (RMAMs). 4. L538,916, an analogue of MK886 which does not block FLAP, had no effect on either IK or I(K,Ca) at a concentration of 10 microM. 5. Leukotriene C4 (100 nM) had no effect on either IK or I(K,Ca) in RPAMs. MK886 produced its usual increase in I(K,Ca) and also blocked IK, in the presence of leukotriene C4. Similarly, leukotriene E4 (100 nM) did not alter the amplitude of IK. Also, the nonselective leukotriene receptor antagonist ICI 198,615 (3 microM) did not affect IK in RPAMs, and did not affect the response to MK886. 6. Arachidonic acid (10 microM) enhanced I(K,Ca) in both RPAMs and RMAMs. 7. The results show that MK886 markedly affects both IK and I(K,Ca) in a manner similar to that of arachidonic acid and independent of the endogenous production of leukotrienes. It is therefore possible that MK886, which is thought to compete with arachidonic acid for its binding to FLAP, may similarly occupy arachidonic acid binding sites on these K+ channels, and mimic its effects. Alternatively, MK886 might act via non-selective effects on other arachidonic acid metabolites which could modify K+ channel function.
The article reviews the history of development of free-flap skin transplantation and basic role of acad. B.A. Petrov who was the first to show the role of dermatom skin transplantation in vast granulating wounds as the only method saving the life of patients with severe burns. He also suggested to solve an actual problem--deficiency of resources of donor skin--by repeated excision of skin flaps from previously used donor sites and use of cadaver skin. Very important is ales the role of B.A. Petrov in development of such particular questions as the role of patient's condition, wound bed am microbial flora of the wound in survival of skin transplants. In aspect of historical relationships the perspective of new approach to treatment of deep burns by transplantation of ceratinocytes, cultivated outside the patient's organism is shown.
A method to determine the 137Cs soil deposit in situ where the contamination is covered by a clean soil layer is described. The method is based on measurements of the count rates in three energy ranges by a collimated spectrum sensitive detector and their processing. The deposit determination accuracy is 20%. The measurement results are presented and compared with data from soil sampling. The 137Cs contamination maps of areas in Belarus and the Chelyabinsk region of Russia are presented. Measurements of the river Techa bank contamination detected the presence of secondary contamination. This method permits the change of dose rate after land decontamination and the work needed for decontamination and its efficiency to be predicted.