Broad-spectrum antibacterial and pro-regenerative effects of photoactivated Photodithazine-Pluronic F127-Chitosan polymer system: In vivo study.

Emerging global danger of multidrug resistant microbes makes it essential to explore new approaches to treat infections. We studied antibacterial and pro-regenerative effects of photodynamic therapy (PDT) performed with water solutions of photodithazine and its complexes with Pluronic F127 and chitosan in rat model of full thickness wound (n = 24) infected by an associated Gram-negative and Gram-positive bacteria culture. Laboratory rats were exposed to PDT 24 and 72 h after the injury. Exudate samples were collected before and after PDT for a microbiological study. Autopsy tissues were excised and fixed in formalin on day 4 of the experiment. Fixed tissues were processed and poured into paraffin. Paraffin sections were stained with hematoxylin and eosin and studied by an experienced pathologist. Microbiological analysis revealed that the photoactivation of photodithazine and its complexes suppressed the associated microflora in vivo and inhibited suppurative inflammation in the wounds. The triple Photodithazine-Pluronic F127-Chitosan system possessed the highest antibacterial activity. The morphological study revealed that PDT with photodithazine polymer complexes accelerated wound healing, promoted restoration of microcirculation, facilitated proliferation of fibroblast and vessels and stimulated collagen synthesis. The Photodithazine-Pluronic F127-Chitosan complex may be successfully applied for PDT to prevent and treat suppurative inflammatory diseases of the skin and soft tissues.

Digging deeper: structural background of PEGylated fibrin gels in cell migration and lumenogenesis.

Fibrin is a well-known tool in tissue engineering, but the structure of its modifications created to improve its properties remains undiscussed despite its importance, e.g. in designing biomaterials that ensure cell migration and lumenogenesis. We sought to uncover the structural aspects of PEGylated fibrin hydrogels shown to contribute to angiogenesis. The analysis of the small-angle X-ray scattering (SAXS) data and ab initio modeling revealed that the PEGylation of fibrinogen led to the formation of oligomeric species, which are larger at a higher PEG : fibrinogen molar ratio. The improvement of optical properties was provided by the decrease in aggregates' sizes and also by retaining the bound water. Compared to the native fibrin, the structure of the 5 : 1 PEGylated fibrin gel consisted of homogenously distributed flexible fibrils with a smaller space between them. Moreover, as arginylglycylaspartic acid (RGD) sites may be partly bound to PEG-NHS or masked because of the oligomerization, the number of adhesion sites may be slightly reduced that may provide the better cell migration and formation of continuous capillary-like structures.

Influence of acetic acid on the photocatalytic activity of photosensitiser-amphiphilic polymer complexes in the oxidation reaction of tryptophan.

The effect of acetic acid on the photosensitizing activity of dimegin (DMG), chlorin e6 (Ce6), and their complexes with amphiphilic polymers-Pluronic F-127 and poly-N-vinylpyrrolidone (PVP)-in the model reaction of tryptophan photo-oxidation has been established. It was shown that the photocatalytic activity of photosensitizers (PS), which is characterized by the effective constant of the tryptophan photo-oxidation rate (keff), increases by 1.4 times for DMG, while for Ce6, it decreases by 1.2 times in a weak acidic medium (pH ∼ 4). The influence of acetic acid on the effective constant keff of the tryptophan photo-oxidation rate in the presence of PS-amphiphilic polymer complexes is determined by the nature of the polymer. Thus, the photocatalytic activity of the PS-F127 system decreases at pH ∼ 4.0, and the photocatalytic activity of PS-PVP complexes is insensitive to the presence of acetic acid in the medium. It has been suggested that the observed effects in the PS-F127 system in a weak acidic medium (pH ∼ 4) are associated with the influence of acetic acid on the supramolecular structure of Pluronic F127.

[The experimental evaluation of antiradiation effectiveness of genistein by survival rates and bone marrow hemopoiesis of mice irradiated by X-rays].

The study was aimed at evaluating the radioprotective effectiveness of genistein administered at different times before or after acute irradiation. Evaluation ofradioprotective efficiency was performed by studying the 30-day survival rate, life expectancy, bone marrow hemapoiesis using the method of endogenous and exogenous colony formation. We have established that genistein at a dose of 200 mg/kg when administered 1 hour prior to irradiation has the highest radioprotective efficiency. In this case, genistein protects mice against death due to X-ray radiation at doses LD(50-90/30), increasing their survival rate by 30-44%, and reduces expression of post radiation disorders of bone marrow hematopoiesis.

[The influence of consecutive application of radioprotector B-190 and interleukin-1beta on changes of number of peripheral blood leucocytes and functional status of neutrophils of irradiated mice].

The estimation of efficiency of consecutive application of radioprotector B-190 and interleukin-1beta administered at early times after acute irradiation by studying the changes of the number of peripheral blood leukocytes, neutrophils and lymphocytes, as well as cytochemical research into the contents of glycogen, myeloperoxidase and alkaline phosphatase in neutrophils of the irradiated mice was carried out. It is established that administration of radioprotector B-190 at a doze of 50 mg/kg for 15 minutes before irradiation and interleukin-1beta at a doze of 50 mkg/kg for 15 minutes after irradiation reduces the expressiveness of post-irradiation leukopenia, accelerates restoration of the number of neutrophils and lymphocytes in peripheral blood, normalizes the functional status of neutrophils of irradiated mice to a greater degree than their isolated introduction.

[The experimental evaluation of antiradiation effectiveness of beta-estradiol on survival rates and bone marrow hemopoiesis of X-ray irradiated mice].

The study was aimed at evaluating the radioprotective effectiveness of beta-estradiol following its prophylactic administration in conditions of acute irradiation. Evaluation of the radioprotective efficiency was performed by studying the 30-day survival rate, life expectancy, the structure of irradiated mice death, the bone marrow hematopoiesis using the method of exogenous colony formation. The prophylactic use of beta-estradiol at doses of 20 and 40 mg/kg 5 days before irradiation has been established to protect the exposed mice against radiation death induced by X-rays at doses LD50-90/30, thus increasing their survival rate by 17-58%, and to favor the reduced expression of post radiation disorders of bone marrow hematopoiesis.

Porphyrin effect on the surface morphology of amphiphilic polymers as observed by atomic force microscopy.

Complexes of porphyrin photosensitizers (PPS) with triblock copolymers of ethylene- and propylene oxide - Pluronics(®) - exhibit markedly increased activity in the generation of singlet oxygen in aqueous media, as compared to pure porphyrins. Pluronics are amphiphilic polymers with surfactant properties suitable for a number of medical applications. PPS-Pluronic systems are considered as promising agents for photodynamic therapy which implies generation of singlet oxygen in the water-based human tissue. Importantly, Pluronics are capable of solubilization of not only water-soluble, but also hydrophobic PPS providing their transfer into the aqueous phase. It has been shown earlier that specific interactions of PPS with Pluronics must play a primary role for the photocatalytic properties of PPS-Pluronic systems. In the process of solubilization of a hydrophobic porphyrin by a Pluronic, both components are dissolved in an organic solvent, which is then removed, and the dry film is re-dissolved in water. Apparently, the initial binding between the porphyrin and the lipophilic part of the polymer takes place already at the stage of the film formation. We applied atomic force microscopy (AFM) to visualize structures formed by Pluronics upon their interactions with meso-tetraphenylporphyrin (TPP). We studied the surface structure of Pluronics(®) F87, F108 and F127 crystallized alone or together with TPP on silicon substrates from chloroform solutions. We found Pluronics to form similar dendritic structures independently of their molecular weight and degree of hydrophobicity. In the presence of TPP, though, we observed formation of distinct convex structures on top of the Pluronic dendrites. These structures appeared to consist of multiple flat layers placed on top of each other. Their sizes varied among the three Pluronics. We believe that TPP aggregates interact with the hydrophobic units of Pluronics causing the polymer chains to pack themselves in a distinct manner around those TPP-containing "cores". These interactions apparently direct formation of complexes between the porphyrin and the polymer upon their dissolution in water, thus resulting in the encapsulation of TPP aggregates inside a Pluronic micelle. A single mechanism for the TPP solubilization by Pluronics is consistent with the same catalytic activity of the three TPP-Pluronic systems observed in the photooxidation of tryptophan.

[The impact of surgical correction of obesity (laparoscopic gastro-bypass surgery) under metabolic syndrome on the biochemical blood indicators].

In nowadays the wide propagation of surgical treatment of metabolic syndrome using the laparoscopic gastro-bypass surgery can be explained hy severe consequences of clinical manifestation of metabolic syndrome. The risk of the mentioned method has to be clear-cut assessed. The comprehensive analysis of changes in indicators of metabolism has to be applied to patients with metabolic syndrome before and after laparoscopic gastro-bypass surgery. The study was carried out on the sampling of 41 patients, 16 patients before and 25 after laparoscopic gastro-bypass surgery. In patients with metabolic syndrome after laparoscopic gastro-bypass surgery the normalization of concentration of glucose and glycated hemoglobin was established. The level of triglycerides, low density lipoproteins and reactive protein reliably decreased as compared with indicators of in non-operated patients. After laparoscopic gastro-bypass surgery, the positive dynamics of activity of enzymes of blood serum was noted.

[Effect of indometofen on the survival and bone marrow hemopoiesis of mice exposed to acute external gamma- or X-ray irradiation].

The purpose of the study is evaluation of radioprotective effectiveness of indometofen at its prophylactic administration in conditions of acute irradiation. Evaluation of radioprotective efficiency was performed by studying the 30-day survival rate, life expectancy, structure of deathly irradiated mice, and bone marrow hemopoiesis using methods of endogenous and exogenous colony formation. The prophylactic application of indometofen at doses 30 mg/kg for 5 days before irradiation has been observed to protect mice against radiation death induced by gamma or X-ray exposures at doses LD(50-70/30), increasing their survival rate by 16-44%, and reduce severity of post radiation disorders of bone marrow hemopoiesis.

[The influence of consecutive application of B-190 preparation and interleukin-1beta on survival rate and bone marrow hematopoiesis of irradiated mice].

The purpose of research was the experimental estimation of efficiency of consecutive application of a radioprotector B-190 and means of emergency therapy of radiating injury interleukin-1beta at acute irradiation. An estimation of treatment-and-prophylactic action of the given circuit of introduction of preparations carried out by studying 30 day-survival and average life expectancy of the lost animals, research of bone marrow hemopoiesis. It is established, that consecutive application of a radioprotector B-190 in a doze of 50 mg/kg for 15 mines up to an irradiation and interleukin-1beta in a doze of 50 mkg/kg through 15 mines after irradiating increases survival and prevents decrease in quantity of CFU-S9 at the irradiated mice in the greater degree, than their isolated introduction.

[Assessment of the results of determination of the blood level of dehydroepiandrosterone sulfate by using various commercial reagents].

The results of determination of the blood levels of dehydroepiandrosterone (DHEA) sulfate (DHEA-S) were comparatively assessed, by using the test systems "Steroid-IEA-DHEA-sulfate" (ZAO "Alkor Bio" (Saint Petersburg, Russia)) and "DHEA-S ELISA ("DRG Instruments GmbH (Germany)). The studies were conducted in apparently healthy 19-59-year-old women living in the middle belt of Western Siberia. They revealed the high sensitivity of the study test systems to age-related changes in the blood concentration of DHEA-S. The normal blood DHEA-S concentrations levels given in the instruction to the "DHEA-S ELISA" test systems were found to be decreased in they are used to measure the content of the above analyzed parameter in women aged 19-39 years.

[Transfection with the E1A and E1B-19kDa oncogenes does not prevent rat embryo fibroblasts from cell cycle arrest after gamma-radiation]. / Perenos onkogenov E1A i E1B-19kDa v émbrional'nye fibroblasty krysy ne otmeniaet sposobnosti kletok ostanavlivat'sia v kletochnom tsikle posle gamma-oblucheniia.

Introduction of the E1A early region of the human adenovirus type 5 impairs the ability of mammalian cells to arrest the cell cycle at G1/S after damage. Two-parameter fluorescent-activated cell sorting (FACS) with iododeoxyuridine revealed the radiation-induced G1/S arrest in rat embryo fibroblasts transformed with the complementing E1A + E1B-19 kDa oncogenes. This was due to selective inhibition of CycIE/Cdk2-associated kinase activity, while activities of type 2 kinase and of CyclA/Cdk2 complexes remained unchanged. The inhibitor of G1-phase cyclin kinases, p21/Waf1, was accumulated and interacted with target kinases both in normal and in transformed cells after irradiation. As shown by immunoprecipitation, p21/Waf1 formed complexes with the E1A on coproducts in the transformants, which possibly accounted for its functional inactivation. Kinase modification in cyclin-kinase complexes was assumed to play a key role in regulation of cyclin-dependent kinases in the transformants with inactivated p21/Waf1.

Approaches to development of microencapsulated form of the live measles vaccine.

Development of delivery of antigens and antigenic complexes using microcapsules or microgranules made of pH-dependent polymers is one of several high priority directions of modern vaccinology. These polymers should protect the virus from acid gastric medium, dissolve or swell readily in weakly alkaline intestinal medium, in no way decrease the specific activities of viral antigens, promote their penetration into intestinal mucosa, and possess adjuvant properties. The State Research Center Vector and "DELSI" are developing the technology for production of microencapsulated form of the live measles vaccine L-16 viruses for oral administration. The authors have so far succeeded in selecting and characterizing a number of polymers that are promising for microencapsulated vaccine and for testing of virus titers and immune response of experimental samples of a new vaccine in animals. Control of samples in guinea pigs demonstrated that the encapsulated measles virus retained its specific activity and capability for inducing immune response in experimental animals.

Morphology and tuber formation of in-vitro-grown potato plants harboring the yeast invertase gene and/or the rolC gene.

Growth and tuber formation of transgenic potato plants (Solanum tuberosum cv. Désirée) harboring the yeast invertase gene and the rolC gene individually or in combination under the transcriptional control of the patatin promoter were investigated under different conditions in vitro. Plants expressing only the invertase gene were morphologically similar to control plants. rolC transgenic plants had an increased tiller number, improved root growth, and a higher total biomass. Tuber formation and growth were altered by the introduced transgenes. The sucrose requirement to induce tubers was shifted to lower or higher concentrations for invertase- or rolC-expressing clones, respectively. In addition, rolC plants formed tubers of altered morphology. A comparison with soil-grown plants showed that morphological parameters can be predicted to some extent from in vitro studies, while for reliable prescreening of parameters concerning tuber formation and growth, an optimization of currently used protocols is necessary.

[Monoclonal antibodies to the HNK-1 antigen of human natural killers]. / Monoklonal'nye antitela k HNK1-antigenu estestvennykh killerov cheloveka.

The ability of monoclonal antibodies (MAb) to HNK1 antigen of natural killers (NK), previously purified by affinity chromatography, to react with human blood lymphocytes has been studied by flow cytometry. The results obtained point to some cells, among blood lymphocytes, which have antigenic determinants to these MAbs. A decrease in the NK cell cytotoxic activity was shown after addition of MAb in comparison with the control. This enables us to suggest a reactivity of these MABs to the CD57 leucocyte differential antigens.