[Dual role of photosensibilizator merocyanine 540 as a bactericidal agent and immune reaction regulator].

AIM: Develop conditions for inactivation of staphylococcus by using photosensibilizator merocyanine 540 (MC540) for the production of antigenic preparation (AP). Study some of immune reactions to AP and the possibility of regulation of DTH reaction to AP under the effect of MC540. MATERIALS AND METHODS: Merocyanine 540 (MC540, Sigma-Aldrich, Switzerland) is used in the study. MC540 and Staphylococcus aureus, strain 78 (Sa78) were irradiated by light of a mercury-quartz lamp DRSH-250 (Zelenograd). C56BL/6 line mice were immunized once by subcutaneous administration of AP. DTH reaction was tested 7 days after the immunization. Functional activity of peritoneal exudate macrophages was determined 1 and 9 days after the immunization. Immune modulating effect of MC540 in DTH was determined after its per os administration to mice 1 hour after AP sensibilization. RESULTS: In order to obtain AP, S. aureus suspension at the concentration of 2.5 x 10(7) CFU/ml in 25 microM MC540 solution and 0.25 M NaCl solution were exposed to irradiation for 5 minutes. During DTH reaction induction its intensity dependence on AP dose was revealed. A persistent increase of a lysosomatic enzyme cathepsin D in macrophages of peritoneal exudate after a single administration of AP was noted. During MC540 irradiation an accumulation of photoproducts that have a pronounced immune suppression effect in DTH reaction had a dose-dependent character. CONCLUSION: Use of saline allows to increase bactericidal potential of a photosensibilizator (PS). However during therapy of localized forms of infection a possible immune modulating effect of PS on macro organism should be considered. By varying PS dose and irradiation time not only maximum bactericidal effect can be achieved but also regulation of inflammatory reactions in the area of PS effect can be ensured.

[Bactericidal action of non-thermal plasma on biofilms formed in vitro and within a root channel].

AIM: Evaluation of efficiency of non-thermal plasma as bactericidal agent affecting biofilms formed in vitro and on walls of a root channel. MATERIALS AND METHODS: The multiple antibiotic resistant strain Staphylococcus epidermidis isolated from pulpitis was used. Biofilms formed in vitro on the plastic surface and ex vivo at the walls of the root canal were treated with plasma torch formed by argon:air (9:1) mixture eradiated with 100 kHz electrtomagnetic field. Bacterial viability was determined by plating and by differential Live/Dead labeling. RESULTS: The dose-dependent decrease in living bacteria was demonstrated. The three-step kinetics ofbacterial killing was observed. Total elimination ofup 10(9) CFU/sample was reached at exposition of 240 s or more. CONCLUSION: The non-thermal plasma effectively destroyed bacterial biofilms within root channels.

[New approaches to therapy of persistent infections: elimination of intracellular Chlamydai trachomatis by exposure to low temperature argon plasma].

AIM: Study microbicidal activity of low temperature argon plasma (LTP) that is a stream of partially ionized argon having macroscopic temperature of the environment against Chlamydia trachomatis obligate intracellular parasites. Study viability of host cells in parallel. MATERIALS AND METHODS: McCoy line cells infected with C. trachomatis (Bu-434/L2 strain) were exposed to LTP obtained by using atmospheric pressure plasma SHF generator. Intracellular localization of chlamydiae was visualized by luminescent microscopy. RESULTS: Exposure of infected McCoy line cells resulted in the destruction of chlamydia inclusions and practically complete elimination of intracellular bacteria. At the same time LTP exposure did not result in immediate death of host cells, an insignificant reduction of the number of cells was observed 24 hours after the exposure to LTP. CONCLUSION: The effect of LTP for elimination of intracellular chlamydia without significant changes in viability of eukaryotic host cells was demonstrated.

[Prospects for the use of low-temperature gas plasma as an antimicrobial agent].

Results of application of LTP at atmospheric pressure as an antibacterial agent during the last decade are considered with reference to physicochemical mechanisms of its bactericidal action. The principles of designing modern LTP sources are described in conjunction with the results of LTP application against pathogenic bacteria in vitro and in biofilms. The possibility to destroy biofilm matrix by LTP is estimated along with the results of its testing for the treatment of acute and chronic wound surfaces. Prospects for the development of "plasma medicine" in this country and abroad are discussed with special emphasis on its advantages, such as the absence of long-acting toxic compounds, small probability of spontaneous mutations accounting for resistance to LTP, relatively low cost of LTP sources, independence of LTP effect of the surface relief, painless application.

[Immunobiological features of bacterial cells of medical biofilms].

Biofilm is a integrated multucellular organism with own cycle of development, cooperative behavior of units forming it, which coordinated by QS-system based on production of signal molecules or autoinductors and ability of bacteria to receive these signals. Presence ofbacteria attached to surface of biomedical devices and formation of bacterial biofilms in the microorganism could lead to chronic inflammation, which characterized by presence of macrophages and lymphocytes in the focus of inflammation as well as proliferation of connective tissue, accumulation of matrix proteins and stimulation ofangiogenesis. Process of biofilm formation associated with activation of QS-system of different agents including potentially dangerous bacteria plays certain role in exacerbation of gastric and duodenal ulcer diseases, Crohn's disease, myocarditis, asthma, diabetes mellitus, cardiovascular and other somatic diseases. Detachment of biofilm could lead to enter ofbac-teria in bloodsream and vascular embolism. Issues related to ability of bacteria of biofilms to modulate immune response and potential for the emerging response to influence the biofilm growth and level of expression of bacterial virulence are discussed. Modem views on mechanisms of interaction of bacteria of exopolysaccharide biofilm with host's immune response factors are reviewed. The most perspective ways to control for biofilm formation and their disruption using newly developing drugs are outlined.

[Mechanisms of Chlamydia trachomatis and herpes simplex virus persistence during viral-bacterial infection].

Possible mechanisms of persistence on the example of Chlamydia trachomatis in conditions of herpes simplex virus type 2 (HSV-2) superinfection in vitro and in vivo are described. Emergence of persisting forms of Chlamydia as well as factors influencing on this process are considered. Contemporary views on pathogenesis of viral-bacterial infection with HSV-2 and C. trachomatis as well as interactions of the agents with local immunity factors are described. It was suggested that there are signaling pathways through which HSV-2 changes life cycle of Chlamydia.