Combined Effect of Ceftriaxon and Low-Frequency Ultrasound on the Viability of Staphylococcus epidermidis Cells in a Preformed Biofilm.

We studied the effect of low-frequency ultrasound on the antibacterial effect of ceftriaxone for Staphylococcus epidermidis strains isolated from biomaterial of patients with paraimplant inflammation after total replacement of large joints in the plankton and preformed biofilm forms. Low-frequency ultrasound had no antibacterial effect on the plankton S. epidermidis culture or bacterial cells in the biofilm, and combined exposure of the plankton culture to ultrasound and ceftriaxone did not modulate the antibacterial activity of ceftriaxone. The exposure of the biofilm formed by S. epidermidis strains to low-frequency ultrasound increased the sensitivity of bacterial cells to ceftriaxone in a concentration range of 5-200 µg/ml.

Assessment of the systemic immune response in patients with inflammatory complications of large joint implants.

One of the most common reasons for the progressing of aseptic instability of implanted structures in patients with end-stage osteoarthrosis is a disorder of immunogenulatory processes of bone tissue remodeling along with chronic inflammatory response influenced by endoprosthesis wear components. This research features the specifics of systemic immune response in patients with inflammatory complications in late postoperative period after total replacements of large joints. The factor analysis enabled determining the most significant immunological mechanisms associated with the progressing of implant aseptic instability. Pathogenetically significant components involved in the formation of cellular and humoral immune responses in patients with signs of inflammatory activity in late postoperative period have been identified. Our findings can be used in designing diagnostic and prognostic criteria for systemic inflammatory response severity in preoperative monitoring of the condition of patients in need of large joint arthroplasties, and also in detecting the progress of implant aseptic instability.

Kinetics of the Growth of Enterococcus spp. Biofilm Formed by Strains Isolated from Patients with Infectious Complications after Large joint Replacements.

We studied the kinetics of growth of biofilms and plankton forms of Enterococcus spp. strains isolated in implant-associated infection of large joints. The capacity for biofilm formation by enterococci was demonstrated. The following stages of biofilm formation were revealed: biofilm formation and maturation, its degradation, and secondary dissemination. These findings extend our understanding of the wound process caused by enterococci.

Resistance to Antibiotics in Plankton and Biofilm Cultures of Pseudomonas aeruginosa Clinical Strains.

Biofilms formed by Pseudomonas aeruginosa strains isolated from biomaterial of patients with implant-associated infection are characterized by much higher resistance to antibiotics of various classes than plankton cultures of these strains. The concentrations of antibiotics causing the death of 90% of P. aeruginosa biofilm (MIC90) was 2-6 µg/ml for fluoroquinolones, 267-356 µg/ml for cephalosporins, and 92-215 µg/ml for amikacin, which significantly (p<0.05) differed from MIC90 for plankton cultures that did not exceed 0.8 µg/ml for fluoroquinolones, 19 µg/ml for cephalosporins, and 3 µg/ml for amikacin. The degree of the microbial biofilm maturity also affected antibiotic resistance.

Antibiotic Susceptibility of Staphylococcus aureus Plankton and Biofilm Forms Isolated in Implant-Associated Infection.

Comparison of activity of antibiotics against Staphylococcus aureus strains in their plankton form and in biofilms of varying maturity showed that the concentrations of antibiotics causing death of 90% S. aureus strains (MIC90) in their plankton form was 0.07-2.80 µg/ml and significantly (p<0.05) differed from MIC90 concentrations (3-245 µg/ml) for the strains in 24 and 48 h biofilms. MIC90 value was affected by the degree of biofilm maturity: microbial resistance in 48-h biofilms for all analyzed antibiotics was significantly (p<0.05) higher than in 24-h biofilms.

Cell Immunity in Implant-Associated Infections Caused by Biofilm-Forming Microorganisms.

High biofilm-forming capacity of Staphylococcus spp. strains isolated from biomaterial of patients with infectious complications after primary knee replacement developed within 6-12 months after surgery was experimentally demonstrated. Differential leukocyte counts and some indicators of cell immunity in these patients were compared with those in patients without purulent complications and healthy volunteers. In patients with implant-associated infection, the relative numbers of T cells (both T-helpers and T-suppressors) B cells were significantly (p<0.05) reduced, while the number of NK cells was significantly increased in comparison with the corresponding parameters in other groups. The revealed changes attest to cell immunity failure in biofilm infection.

The Effect of Azithromycin on Biofilms Formation by Pathogens of Implant-Associated Infection in Large Joints.

We studied the effect of subbacteriostatic azithromycin concentrations on the formation of microbial biofilms by Pseudomonas aeruginosa strains that caused implant-associated infection of large joints. Azithromycin in subinhibitory for planktonic cells concentrations 0.01-0.02 µg/ml stimulated biofilm formation by both clinical and reference P. aeruginosa strains, while in concentrations of 1 µg/ml and higher completely inhibited the growth of both reference and clinical plankton P. aeruginosa strains, but stimulated biofilm formation. Increasing azithromycin concentration to 10 µg/ml led to inhibition of P. aeruginosa biofilm growth.

Biofilm Formation by Gram-Negative Bacteria during Implant-Associated Infection.

Nonfermenting gram-negative bacteria and enterobacteria isolated from various biomaterials of patients of the orthopedic trauma hospital with implant-associated infection demonstrated significantly (p<0.05) higher biofilm formation capacity than the reference strains. The differences in biofilm formation kinetics were revealed: biofilm maturation and the beginning of its dispersion after 48-h incubation in enterobacteria and longer biofilm maturation phase in nonfermenting gram-negative bacteria. It was found that the strains isolated from sonication fluid have reliably (p<0.05) higher propensity to biofilm formation than bacteria isolated from aspirate and wound exudate.

Local Treatment of Local Staphylococcal Infection with Complex Preparations Based on Metal Nanoparticles in the Experiment.

Antibacterial activity of powdered preparations based on copper and silver nanoparticles was compared with activity of the reference preparation Baneocin on the model of local staphylococcal infection in white rats. The developed preparations exhibited pronounced antibacterial activity against methicillin-resistant S. epidermidis strains in vivo significantly (p<0.001) exceeding that of Baneocin, reduced microbial contamination of the wound on day 5 of study by 2 lg and more in comparison with bacterial load before treatment, and provided effective decontamination of the wound within 7-10 days.

Particularities of Bone Regeneration in Rats after Implantation of Polycaprolactone Scaffold Mineralized with Vaterite with Adsorbed Tannic Acid.

We studied the particularities of osteo- and angiogenesis in albino rats after implantation of polycaprolactone scaffolds mineralized with vaterite with adsorbed tannic acid in the femoral bone defect. It was found that the processes of angio- and osteogenesis in the bone tissue after scaffolds implantation depend on their biocompatibility. Implantation of non-biocompatible scaffolds was followed by activation of angio- and osteogenesis aimed at separation of these scaffold from surrounding tissues. Implantation of polycaprolactone/vaterite scaffolds containing tannic acid stimulated angio- and osteogenesis leading to vascularization and bone tissue formation in the matrix. This demonstrate prospects of clinical approbation of these scaffolds for stimulation of bone regeneration in traumatological and orthopedic patients.

Application of Preparations Containing Copper Nanoparticles for the Treatment of Experimental Septic Wounds.

Regenerative activity of locally applied drugs based on copper nanoparticles was compared on white male rats with an experimental purulent wound infected with clinical polyantibiotic resistant strains of Staphylococcus aureus. The use of a suspension of copper nanoparticles and complex drugs based on chitosan and starch with copper nanoparticles led to a rapid reduction of the wound area and elimination of the wound-contaminating agent, which confirmed high antibacterial and regenerative activity of copper nanoparticles in the composition of the studied drugs.

Soft Tissue Regeneration under the Effect of Wound Coating Based on Chitosan (Natural Biopolymer).

We developed wound coating based on natural biopolymer chitosan with additional components (ceruloplasmin, L-asparaginic acid, and glycerol). Experiments on albino male rats demonstrated its regeneratory, antioxidant, and antibacterial effects on wounds involving all layers of the skin. Due to chemical composition and buffer component, the biodegraded wound coating optimizes all phases of the wound process, accelerates by 22-28% the reparative regeneration, and leads to anatomic and functional restoration of injured sites. High absorption capacity recommends its use in the treatment of wounds with profuse exudation.

[SOFT TISSUE REPAIR UNDER CONDITIONS OF EXPERIMENTAL SEPTIC WOUND.]

The effectiveness of a new complex preparation based on starch containing active copper (0.05 - 0.07 mass %) and silver 0.03 - 0.05 mass %) nanoparticles was studied in animals with experimental fill-flap septic wounds. Localized application of complex preparation (0.3 g per animal) by uniform layer on 5th, 7th, and 9th day upon wound induction led to significant reduction in wound surface (according to planimetric analysis) at all control periods, in contrast to reference group. There was statistically significant (p < 0.001) decrease in malondialdehyde (by 23%) and increase of serum enzymatic antioxidant ceruloplazmin activity (by 20.5%) in rat blood serum compared to the corresponding indexes in animals before therapy. These results are indicative of the suppression of peroxidation processes and stimulation of antioxidant system. The complex preparation exhibited positive influence on soft tissue repair processes, lipid peroxidation processes, and activity of the antioxidant system.

[Certain aspects of diagnostic of osteopenia syndrome in traumatology and orthopedics.]

The osteopenia syndrome characterizing by progressing decrease of bone tissue mass and lowering of its strength due to damage of its micro-architectonics counts in the most significant medical social diseases. The timely detection of disorders of bone tissue remodeling is a complicated diagnostic task as far as laboratory diagnostic of osteo-deficiency conditions is based on finding indirect indices of bone tissue metabolism. The instrumental methods of evaluation of condition of bone structures provide no possibility to detect their early damages and to manage dynamic observation of implemented anti-resorption therapy. The study was carried out to develop complex approaches to laboratory instrumental diagnostic of osteo-deficiency conditions. The comprehensive laboratory instrumental examination of patients with deforming osteoarthritis of hip joint including evaluation of bone tissue mineral density, indices of calcium phosphorus metabolism, markers of bone resorption and bone formation, activity of inflammation process. The study established activation of bone resorption and inhibition of bone formation in patients with high activity of inflation process.

[Structural and Functional Properties of Vascular Endothelium].

We have summarized in this paper main conceptions on structure and function of vascular endothelium with special attention to the role of caveolae both in regulation of function of endothelium itself and transvesicular transport of metabolic substrates. We have also described the role of shear stress in activation of vascular endothelium and putative mechanisms of its action.

Metal nanoparticles reduce bacterial contamination of experimental purulent wounds.

Bacterial contamination of experimental purulent wound in rats treated by local applications of suspension of copper and zinc nanoparticles and a combined drug based on chitosan and copper and zinc nanoparticles was evaluated. Applications of copper nanoparticle suspension and combined drug with copper and zinc nanoparticles and chitosan led to rapid elimination of the bacterial contaminant. Antibacterial activity of zinc nanoparticles was less pronounced, but the effect also differed significantly from the reference group.

[Structural and Functional Properties of Vascular Endothelium].

We have summarized in this paper main conceptions on structure and function of vascular endothelium with special attention to the role of caveolae both in regulation of function of endothelium itself and transvesicular transport of metabolic substrates. We have also described the role of shear stress in activation of vascular endothelium and putative mechanisms of its action.

[Reparative regeneration of rat soft tissues is affected by a wound-healing composite].

We researched influence of original wound-healing composite, including chitosan and nanoparticles of copper and zinc, on specific of reparative regeneration of an experimental soft tissue full layer rat's wounds, which were conditionally aseptic and infected. The composite stimulation of reparative regeneration is related both to its antibacterial effect, and to the influence on the state of structural biopolymers of the connecting tissue.

Protective effect of transplantation of neonatal liver cell nuclei on the model of acute toxic hepatitis.

We present the results of comparative analysis of functional and morphological changes in the liver of animals with experimental CCl(4)-induced hepatitis under conditions of transplantation of neonatal liver cells and nuclei. It was found that transplantation of neonatal liver cell nuclei in acute toxic hepatitis provides better functional and structural state of the target organ.