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Electrospun membranes containing curcumin were prepared from poly(L-co-D,L-lactic) acid and polyvinylpyrrolidone. The effect of curcumin concentration on the solution viscosity and the morphology of fiber was studied. Curcumin solubility in aqueous solutions was enhanced by the formation of curcumin/polyvinylpyrrolidone water-soluble complex. Curcumin physico-chemical and therapeutic properties within the membranes were preserved upon UV-Vis light irradiation, as a part of the membranes sterilization. The biomaterials showed antibacterial activity against pathogenic microorganisms such as Staphylococcus aureus and Candida albicans. In-vitro experiments against HeLa and Graffi tumor cells and white blood cells (peritoneal macrophages and spleen lymphocytes) revealed potential biomedical application of the membranes. Electronic Supplementary Material (ESM) The online version of this article (doi: 10.1007/s12221-020-9473-z) contains supplementary material, which is available to authorized users.

Anaerobic microbial biodegradation of cellulose containing wastes generated during the long-term manned space missions is a key technological approach for resolving the problem of wastes accumulated onboard of the spacecraft. Herewith are presented data on the possibilities of structurally stable multispecies microbial consortia originating from methanogenic bioreactors to decompose different cellulose substrates – filter paper, medical gauze and vegetable mix as potential cellulose wastes during space missions. The rates of biodegradation processes carried out at mesophilic and thermophilic conditions are not only measured and compared but are providing new opportunities for development of technology for microbial biodegradation of cellulose-rich organic wastes. Moreover, the studies have shown that paper and gauze hydrolysis with the help of cellulolytic bacterial communities can be an effective component of utilization of cosmonaut hygiene items. Biodegradation of plant wastes by community of anaerobic bacteria is promising and applicable tool also under terrestrial conditions. Light microscopy of bacterial communities reveals the presence of Gram-positive spore forming bacilli (short and long forms, bipolar and dividing cells) and typical clostridia forms.

This paper reports on the production of Ag nanoparticles (AgNPs) in a water solution based on a two-phase pulsed laser procedure in view of therapeutic ophthalmological applications requiring AgNPs size of ≤10 nm with a narrow size distribution. Nanoparticles of this size scale are capable of penetrating the complex ocular barriers, thus ensuring effective non-invasive drug delivery to the retina. Moreover, the ocular irritation, which is currently associated to the conventional ocular drug administration routes, would be avoided. In the first phase, AgNPs larger than 20 nm were fabricated via laser ablation of a Ag target in water by irradiation with the fundamental wavelength (λ = 1064 nm) generated by a Nd:YAG laser. During the second phase, to reduce the mean size of the as-obtained nanoparticles and properly adjust the size distribution, the water colloids were additionally irradiated with the ultraviolet harmonics (355 nm and 266 nm) of the same laser source. The effect of the key laser parameters - wavelength, fluence and laser exposure time - upon the nanoparticles morphology was studied. The most suitable post-ablation treatment of initial colloids was obtained by a consecutive irradiation with the third (λ = 355 nm) and the fourth (λ = 266 nm) harmonics of the fundamental laser wavelength. By using this approach, a synergistic effect between two mechanisms of light absorption by AgNPs was induced. As a result, contaminant-free colloids of AgNPs with sizes of less than 10 nm and quite a narrow size distribution with a standard deviation of 1.6 nm were fabricated. The toxic effect of the as-produced AgNPs on Gram-positive and Gram-negative bacteria and Candida albicans was explored. The most efficient action was reached against Pseudomonas aeruginosa and Escherichia coli. A potential application was proposed of the synthesized AgNPs colloidal aqueous solutions with antimicrobial action as a non-invasive method for ocular infections prevention and treatment.

Various metal phthalocyanines have been studied for their capacity for photodynamic effects on viruses. Two newly synthesized water-soluble phthalocyanine Zn(II) complexes with different charges, cationic methylpyridyloxy-substituted Zn(II)- phthalocyanine (ZnPcMe) and anionic sulfophenoxy-substituted Zn(II)-phthalocyanine (ZnPcS), were used for photoinactivation of two DNA-containing enveloped viruses (herpes simplex virus type 1 and vaccinia virus), two RNA-containing enveloped viruses (bovine viral diarrhea virus and Newcastle disease virus) and two nude viruses (the enterovirus Coxsackie B1, a RNA-containing virus, and human adenovirus 5, a DNA virus). These two differently charged phthalocyanine complexes showed an identical marked virucidal effect against herpes simplex virus type 1, which was one and the same at an irradiation lasting 5 or 20 min (Δlog=3.0 and 4.0, respectively). Towards vaccinia virus this effect was lower, Δlog=1.8 under the effect of ZnPcMe and 2.0 for ZnPcS. Bovine viral diarrhea virus manifested a moderate sensitivity to ZnPcMe (Δlog=1.8) and a pronounced one to ZnPcS at 5- and 20-min irradiation (Δlog=5.8 and 5.3, respectively). The complexes were unable to inactivate Newcastle disease virus, Coxsackievirus B1 and human adenovirus type 5.

Fibrous materials of poly(l-lactide- co-d,l-lactide), poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol), and curcumin were prepared by electrospinning. The incorporation of poly(ethylene glycol) in the fibers caused a decrease in the mean fiber diameters down to 700 nm and in the water contact angle value, the latter being equal to 0 at poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol) 60/40 weight ratio. The water contact angle values of poly(l-lactide- co-d,l-lactide)/curcumin fibrous materials considerably exceeded those of films of the same composition (approximately 120° as compared to approximately 95°, for electrospun mats and solution-cast films, respectively). Curcumin affected the thermal stability of the fibrous materials and the crystallinity degree of the polymers. The mechanical properties of the electrospun materials also depended on the composition of the polymer matrix and the amount of curcumin therein. In the curcumin-containing fibers, curcumin was found in the amorphous state, while higher antioxidant activity was exhibited by poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol)/curcumin fibrous materials. In vitro determination of the activated partial thromboplastin time and prothrombin time showed that poly(l-lactide- co-d,l-lactide)/curcumin fibrous materials displayed anticoagulant activity. Antibacterial effect toward Staphylococcus aureus was manifested by the curcumin-containing mats.

Activity of three photosensitizing phthalocyanine derivatives was tested for photodynamic inactivation towards two coated and two non-enveloped viruses - bovine viral diarrhea virus (BVDV), influenza virus A(H3N2), poliovirus type 1 (PV-1) and human adenovirus type 5 (HAdV5). In the case of coated viruses, a combination of virucidal and irradiation effects was registered by octa-methylpyridyloxy-substituted Ga phthalocyanine (Ga8) toward BVDV, whereas tetra-methylpyridyloxy-substituted Ga phthalocyanine (Ga4) revealed a marked photoinactivation only. No such effect was observed towards influenza A virus. In contrast, the photoinactivating potential of Ga4 and Ga8 marked very high values on naked viruses, especially on HAdV5, at which both the virucidal as well as the irradiation effects became combined.

Antibacterial photodynamic therapy is a pioneering method for the inactivation of pathogenic bacteria. Four tetra alkyl-substituted cationic phthalocyanines with different hydrocarbon chains attached to the pyridyloxy group were synthesized. These photodynamic sensitizers were studied for antibacterial inactivation of a multidrug-resistant strain of Gram-negative bacterium Aeromonas hydrophila. Aeromonas species are recognized as etiological agents of a wide spectrum of diseases in humans and animals. The uptake of phthalocyanines by the bacterial cells decreased with an increase in cell density. Following the phthalocyanine solubility from hydrophilic to hydrophobic complexes, the accumulation capacity increased. Full inactivation was achieved with phthalocyanine with (methoxy) pyridyloxy substitution following a short exposure time, low drug concentration and mild irradiation. Although the phthalocyanine with the longest hydrocarbon chain (C12) has some toxic effect in the absence of light, substantial phototoxic effect was obtained with the optimal combination of drug-irradiation parameters.

New microfibrous materials from polylactide and polyvinylpyrrolidone or polyethylene glycol loaded with the natural polyphenolic compound curcumin have been prepared by one-pot electrospinning. The incorporation of curcumin in the fibers contributes to shielding curcumin from photodestruction and to enhancement of the mechanical properties of the fibers. Moreover, the formation of hydrogen bonds between curcumin and polyvinylpyrrolidone or polyethylene glycol facilitates the drug release. Curcumin release provides for the antibacterial and anticoagulant activity of the curcumin-loaded mats and prevents adhesion and aggregation of platelets onto the surface of the mats. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42940.

An experimental oral pig model was used to assess the pathogenic and immunogenic potential of Yersinia enterocolitica serotype O:8 wild-type strain 8081-L2 and its lipopolysaccharide (LPS) mutant derivatives: a spontaneous rough mutant 8081-R2, strain 8081-DeltawzzGB expressing O-antigen with uncontrolled chain lengths, and strain 8081-wbcEGB expressing semirough LPS with only one O-unit. Microbiological and immunological parameters of the infected pigs were followed from day 7 to 60 postinfection. The wild-type and all LPS mutant strains persisted in the lymphoid tissue of tonsils and small intestines, causing asymptomatic infection without any pathological changes. Although the pig is known as a reservoir of Yersiniae, a precise analysis of pathogenic and immunogenic parameters based on different in vitro tests (hematological response, killing ability of leukocytes and blood sera, antibody response, hydrogen peroxide production by macrophages, classical and alternative pathways of complement activation), revealed significant attenuation in the pathogenicity of the LPS mutant strains but not the loss of immunogenic potential. In comparison with the other strains, strain 8081-DeltawzzGB demonstrated more continuous leucocytosis with monocytosis, higher invasive potential, significant activation of hydrogen peroxide production by macrophages and an effective immunoglobulin G immune response accompanied by relevant histological immunomorphological rearrangements.

Experimental infection with Burkholderia pseudomallei was successfully produced after a single intravenous challenge of 2-month-old pigs with a dose of 5.0 x 10(9) bacterial cells. Clinical, paraclinical and morphological findings of the infectious process and post-infectious immunity were examined up to day 30 post infection (p.i.). A transient and short hyperthermia accompanied by enhanced and longer demonstrated pulse frequency. An increased erythrocyte sedimentation rate and tachypnea were observed too after clinical examination. The infection starts with significant leucopenia, and a reduced number of alveolar and peritoneal macrophages which have been overcome in the latest intervals of infection. In contrast, the phagocytic activity of leucocytes was statistically increased during the course of infection and up to day 15 p.i. in the case of alveolar macrophages. Burkholderia pseudomallei was able to colonize the lungs during the whole experiment and was only present 3 days in the spleen and mesenterial lymph nodes (MLN). Significant antibody response was developed as early as day 7 p.i. Hyperaemia, haemorrhages and necrotic foci were found in the brain, liver spleen and MLN. Lung tissue was also hyperaemic, with formation of small abscesses and signs of catarrhal pneumonia. Data obtained in this study revealed that B. pseudomallei causes a chronic generalized infection in pigs, even after intravenous challenge.

SUMMARY Introduction: Many of oral diseases are caused by microorganisms. The emergence of antibioticresistant strains, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis, stimulated a search for alternative treatments. Such an alternative method is photo-activated disinfection. The aim of this study is to compare the antimicrobial properties of four new photosensitizers-methylene blue, haematoporphyrin and new Ga, Zn- phtalocyanines after the laser radiation (630 nm) against Staphylococcus aureus. Materials and methods: For the study gram-positive Methicillin-resistant Staphylococcus aureus 1337 from collection of the Institute of Microbyology, Bulgarian Academy of Science is used. For PAD is used source of light which activates photosensitizer trough emission of visible light at a specific wavelength. Suspensions of Staphylo- coccus aureus was irradiated with diode laser (630 nm) in the presence of methylene blue, haematoporphyrin and new Ga, Zn- phtalocyanines. There were two control groups: samples that were only treated with dye and samples that were exposed neither to the laser light nor to dye. Results: Reduction in the viability of Staphylococcus aureus was achieved with some of the photosensitizers and light associations. Conclusions: Photoactivated disinfection appears as an effective method of Staphylococcus aureus inactivation.

Patients undergoing joint surgery and blood transfusion were studied. Serum and leukocyte bactericidal tests in vitro against Salmonella typhimurium and Yersinia enterocolitica were carried out preoperatively as well as on the 1st, 3rd and 7th days after the operation. The serum complement (C3 and C4) concentrations were determined at the same intervals. It was found that after blood transfusion the bactericidic activity of sera and the serum C3 complement concentrations were increased. In contrast the killing ability of leukocytes was suppressed.

The current survey investigates the effect of four polysaccharides isolated from fresh leek or alcohol insoluble substances (AIS) of leek on the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) from phagocytes. The ability of the polysaccharides to activate serum complement was also investigated. Despite the lack of antioxidant activity, the pectic polysaccharides significantly decreased the production of ROS by human neutrophils. Polysaccharides isolated from AIS markedly activated RAW 264.7 macrophages for RNS production in a concentration-dependent manner. The Western blot analysis revealed that this effect was due to the stimulation of the inducible nitric oxide synthase protein expression of macrophages. The polysaccharides extracted from AIS with water showed the ability to fix serum complement, especially through the alternative pathway. It was found that the polysaccharide that has the highest complement-fixing effect is characterized by the highest content of uronic acids and the highest molecular weight.

The Gram-negative, oral bacterium Aggregatibacter actinomycetemcomitans has been implicated as the causative agent of several forms of periodontal disease in humans. The new periodontal disease treatments are emergence in order to prevent infection progression. Antimicrobial photodynamic therapy (a-PDT) can be a useful tool for this purpose. It involves the use of light of specific wavelength to activate a nontoxic photosensitizing agent in the presence of oxygen for eradication of target cells, and appears effective in photoinactivation of microorganisms. The phthalocyanine metal complexes of Pd(II)- (PdPcC) and Al(III)- (AlPc1) were evaluated as photodynamic sensitizers towards a dental pathogen A. actinomycetemcomitans in comparison to the known methylpyridyloxy-substituted Zn(II) phthalocyanine (ZnPcMe). The planktonic and biofilm-cultivated species of A. actinomycetemcomitans were treated . The photophysical results showed intensive and far-red absorbance with high te ndency of aggregation for Pd(II)-phthalocyanine. The dark toxicities of both photosensitizers were negligible at concentrations used (< 0.5 log decrease of viable cells). The photodynamic response for planktonic cultured bacteria was full photoinactivation after a-PDT with ZnPcMe. In case of the newly studied complexes, the effect wa s lower for PdPcC (4 log) as well as fo r AlPc1 (1.5-2 log). As it is known the bacterial biofilms were more resistant to a-PDT, which was confirmed for A. actinomycetemcomitans biofilms with 3 log reductions of viable cells after treatment with ZnPcMe an d approximately 1 log reduction of biofilms after PdPcC and AlPc1. The initial results suggest that a-PDT can be useful for effective inactivation of dental pathogen A. actinomycetemcomitans. Key words: Pd(II) and Al(III) phthalocyanines, antimicrobial photodynamic therapy, Aggregatibacter actinomycetemcomitans , periodontal pathogen, biofilms

Water-soluble phthalocyanine complexes of silicon (SiPc1) and germanium (GePc1) were synthesized. The absorbance of SiPc1 in water was with minor aggregation while GePc1 strongly aggregated in water. The fluorescence data in water showed low quantum yields of 0.073 (SiPc1) and 0.01 (GePc1) and similar lifetimes of 4.07 ns and 4.27 ns. The uptake of SiPc1 into Candida albicans cells was two orders of magnitude lower as compared to GePc1 and for both was dependent on the cell density. Fungal cells in suspension were completely inactivated after SiPc1 (1.8 μM) at soft light radiation (50 J cm(-2), 60 mW cm(-2)). The fungal biofilm formed on denture acrylic resin was inactivated with 3 log after fractionated light irradiation.

Visible light-absorbing cationic water-soluble gallium(III) phthalocyanines (GaPcs) peripherally substituted with four and eight methylpyridyloxy groups were synthesized and investigated as antimicrobial photodynamic sensitizers. The inserted large gallium ion in the phthalocyanine ligand is axially substituted by one hydroxyl group which prevents aggregation of the complexes in aqueous solution. The cellular uptake and the photodynamic activity for the representative strains of the Gram positive bacteria methicillin-resistant Staphylococcus aureus(MRSA) and Enterococcus faecalis, of the Gram negative bacterium Pseudomonas aeruginosa and of the fungus Candida albicans in planktonic phase were studied. The tetra-methylpyridyloxy substituted GaPc1 showed lower cellular uptake compared to the octa-methylpyridyloxy substituted GaPc2. The photodynamic activity of the GaPcs was studied in comparison to methylene blue (MB) and a photodynamically active Zn(II)-phthalocyanine with the same substitution (ZnPcMe). Photodynamic treatment with 3.0 μM GaPc1 at mild light conditions (50 J cm(-2), 60 mW cm(-2)) resulted in a high photoinactivation of the microorganisms in the planktonic phase nevertheless the dark toxicity of GaPc1 towards MRSA and E. faecalis. GaPcs against fungal biofilm grown on polymethylmethacrylate (PMMC) resin showed a complete inactivation at a higher concentration of GaPc2 (6.0 μM) and of the referent sensitizer ZnPcMe. However, the bacterial biofilms were not susceptible to treatment of GaPcs with only 1-2 log reduction of the biofilm. The bacterial biofilm E. faecalis was effectively inactivated only with MB. The water-soluble octa-methylpyridyloxy substituted GaPc2 has a potential value for photodynamic treatment of C. albicans biofilms formed on denture acrylic resin.

Phthalocyanines of gallium(III) and indium(III) (GaPc1 and InPc1) bearing four methylpyridyloxy groups on the periphery of the phthalocyanine ring were synthesized. The both phthalocyanines were obtained with a good solubility in water solutions, which make them suitable for application in the Photodynamic therapy (PDT). The absorbance in the Uv-vis region of the complexes is typical for MPc with a highly intensive maximum in the far red spectra (681 nm - 697 nm for GaPc1 and for InPc1, both in DMSO). The fluorescence maxima are red shifted (691 nm/716 nm). The fluorescence quantum yields of the both complexes are lower than that for the unsubstituted MPcs with values of 0.25 for GaPc1 and much lower for InPc1 (0.012), which suggested a quenching from the substituents. The photochemical properties of singlet oxygen generation show quenching curves of "Furane" test with a 1O2 formation that increase significantly in the presence of the heavy atoms such as Ga(III) and especially In(III). Photodynamic efficacy against C. albicans in planktonic media was evaluated with a high photodynamic effect for GaPc1 at low concentrations (0.5 μM, - 3 μM) at mild irradiation parameters (30-60 J cm-2 and 50 mW cm-2). The inactivation of the fungus cells with InPc1 was insignificant even at strong treatment conditions (6.8 μM; 60 J cm-2). The water-soluble phthalocyanine complexes of Ga(III) and In (III) were compared to the recently studied by us water-soluble Zn(II)-phthalocyanine, which was shown to have a high potential for photodynamic inactivation of variety pathogenic bacterial strains.

In the recent decade the applications of photodynamic therapy (PDT) rapidly increase in several topics and one of areas where the PDT in the future will be play significant role is dentistry. The different photosensitizing complexes with a good water solubility and with absorption with an intensive maximum in the red region (630-690 nm), which makes them suitable for photodynamic treatments, were investigated. The photochemical properties of complexes for singlet oxygen generation were investigated and were shown relations between uptake levels and light intensity to achieve increase in photodynamic efficacy. Photodynamic efficacy against fungi Candida albicans and bacteria's E. faecalis, MRSA and S. Mutans in planktonic media was evaluated. The high photodynamic efficacy was shown for SiPc at very low concentrations (0.9 μM) and light doses of 50 J cm-2 by intensity of light 60 mW cm-2. The photodynamic response for E. faecalis, MRSA and S. Mutans, after treatments with different photosensitizers show strong dependence on concentrations of photsensitzers and micro organisms. The level of inactivation of the pathogen bacteria's from 1-2 degree of initial concentration up to full inactivation was observed. The studied complexes were compared to the recently studied Methylene blue, Haematoporphyrine and tetra-methylpirydiloxy Zn(II)- phthalocyanines and experimental results show that some of them have a good potential for inactivation of representative pathogenic bacterial strains. Experimental results also indicate that photodynamic therapy appears an effective method for inactivation of oral pathogenic bacterias and fungi.

BACKGROUND: Leek (Allium porrum) is very commonly used vegetable in Bulgaria and is distinctive with high content of bioactive components. Previously we obtained five crude pectic polysaccharides from leek through consecutive extraction. Some of them appeared to be good stimulators of the immune system. Schols and Voragen investigated the composition of modified hairy regions of pectic polysaccharides isolated from leek cell walls. Samuelson et al. identified the polysaccharide structures encountered in hairy regions as bioactive. The aim of this work was to study the isolation, composition and biological activities of pectic polysaccharides from leek. RESULTS: Two pectic polysaccharides from leek were isolated through consecutive water and acid extraction. The water extractable pectin had higher polyuronic content, higher protein content and lower neutral sugar content. It was found that next to galacturonic acid they also contain glucuronic acid in ratio 9:1 for the water- and 3:1 for the acid-extractable polysaccharide. The main neutral sugar was galactose. The water-extractable pectic polysaccharide had higher molecular weight (10(6) Da) and homogeneity. It was shown that the pectic polysaccharides from leek have considerable immunostimulating activities. CONCLUSION: Leek polysaccharides have relatively high galacturonic and glucuronic acid content and are distinguished with high biological activity.

Photodynamic therapy (PDT) today is an innovative and not yet widespread light-drug initiated treatment that is based on the photoactive compound irradiated with proper light to produce oxygen species that are toxic to the pathogenic biological objects–bacteria, viruses, tumo r cells. The obstacles that limited the e fficacy of PDT concern to the selectivity and multi-drug resistance prolong time for cellular release and side effects of skin photosensitivity for commercial porphyrin originated photosensitizers (PS) . Now there are very intensive investiga tions for introducing in practice a new, with a least side effects PSs for PDT. The usefulness of the more extended macromolecules structured with proper substituents refers not only to the improved optical properties like far-red and with intensive absorption and emission capacity, but mainly to the ability for selective delivery and adhesion to the target cells, such as bacteria or other pathogens. The present study focuses on the charge effect of photodynamic agent on the uptake capacity toward gram-negative bacteria cells and their further photoinactivation. The multi-drug resistant microorganism Aeromanas hydrophilla , which is causing diseases to fishes and humans, is treated. The new octa-cationic phthalocyanines are designed to compare PDT efficacy to the efficacy of tetra-subs tituted derivatives with the same functio nal peripheral subs tituents. The higher cellular accumulation to the bacteria cells as a result of the high number of positive charges of photosensitizer, leading to the better adhesion to the cellular membranes and improved photoinactivation of bacteria causing superficial and intra-organ infections. These results set a base of a rationale design of covalently octa-substituted phthalocyanines with positive charge for a successful treatment of microorganisms. Keywords: photodynamic therapy, photosensitizers, phthalocyanines, pharmacokinetics, pathogenic microorganisms

Experimental intramuscular infection of hens with Pseudomonas pseudomallei, strain 2796 (1 x 10(9) CFU from a 24-h culture) was reproduced. Clinical, paraclinical and pathomorphological findings were followed from 1 to 30 days after challenge. Haemagglutinin titre, bacterial dissemination in the viscera, number of leucocytes, alveolar (aMa) and peritoneal (pMa) macrophages and their phagocytic activity in vitro were studied. During the course of infection a leucocytosis as well as an increased haemagglutinin titre (1:256) were established. The number of bacteria per gram tissue in the spleen and liver was highest at 1 day post-infection (p.i.). Melioidose bacteria from egg yolk were isolated at 15 and 30 days p.i. Leucocyte and pMa phagocytic activity was maximal at 3 days p.i. unlike the activity of aMa which increased gradually until the end of the study. Inflammatory-necrotic changes were found in the viscera and brain at 3 and 15 days p.i. The investigation of experimental melioidosis infection in hens showed that they are susceptible to P. pseudomallei and this disease takes a generalized subacute course.

Summary Exerimental infection was induced in three inbred mouse strains (BALB/c, BDF1 hybrid and C57BL) by i.p.inoculation with Pseudomonas pseudomallei .The bacterial load in the viscera and the host response induced in different compartments (blood, peritoneal cavity and organs) were determined.Blood cell parameters and peritoneal exudative cell populations were evaluated during the infection with the aid of an automated haematology analyser Technicon H-1.It was found that all mouse strains produced a similar intraperitoneal inflammatory response with predominance of granulocytes at the early stage of infection and subsequent increase of macrophages especially in BDF1 hybrid and BALB/c mice.The highest bacterial count found in the liver and spleen of C57BL was associated with corresponding tissue damage (purulent pneumonia, abscesses in liver, karyorrhexis of hepatocytes and meningoencephalitis).The degree of bacterial load and histological changes found in BALB/c and BDF1 hybrid mice were lower than in C57BL mice.The results show that the variations in the infection magnitude among inbred mouse strains are host-dependent.

Summary The susceptibility of BALB/c, C57BL and BDF1-hybrid mouse strains to Yersinia pseudotuberculosis serovar III infection was studied. The bacterial load in the viscera and brain and the host responses at different levels, i.e. blood, peritoneal cavity and organs were determined. Blood cell parameters and peritoneal exudate cell population were evaluated during the infection using the automated hematologic analyzer Technicon H-1. It was found that BDF1-hybrid mice produced an early peritoneal inflammatory response, while in BALB/c and C57BL mice it was not observed. The high susceptibility of C5 7BL was associated with a great number of microorganisms in the organs and with the corresponding histological changes. It was shown that the magnitude of the inflammation induced by Y. pseudotuberculosis varied among the host strains used. The variations of the susceptibility to Y. pseudotuberculosis among inbred mouse strains suggest the possible role of genetic factors regulating the host defence.

Investigations in the area of laser application in dental practices date back to 1964. Shortly after lasers came to being, they were introduced both in medicine and in dental medicine where they were successfully used for the diagnostics and treatment of a number of diseases. The current literature review presents the nature and properties of lasers and laser beams. Their biological and healing action is discussed. The most common lasers that are employed in dental practices are indicated. The accent is on high-energy lasers used in operative dentistry and periodontology, namely the Ar:Cr:YSGG e Er:YAG lasers, and their emission characteristics. The focus in this literature review is on laser application in periodontal practices. The properties and indications of the most frequently applied lasers are indicated and their advantages are outlined. The latter are due to their specific biological and therapeutic effects both on healthy and on pathologically altered periodontal tissues.The paper also comprises clinical reports by renowned experts in periodontology about laser application in the treatment of different periodontial diseases. Twenty-seven articles are cited.

Summary An experimental infection was induced in the European ground squirrel (Citellus citellus) by intraperitoneally injecting of 1 ml. of microbial suspension, containing 1 times 109 CFU (colony forming units) of Yersinia pseudotuberculosis, serotypes I and III. The infectious process was dynamically followed up from the 1st up to the 30th day, respectively. Account was rendered to the general condition, the internal body temperature and the mortality rate. The phagocytic activity of alveolar macrophages (aMa) and polymorphonuclear leucocytes (PMNL), isolated from the experimental animals, was also determined, as well as the degree of bacterial dissemination into the viscera and the histomorphological changes that found in the parenchymal organs. These investigations confirm the fact that the bacterial agent has a broad spectrum of alaterations in the organism of the host - the European ground squirrel (Citellus citellus) in which the pseudotuberculosis developes as a generalized infection, especially pronounced in the animals that were infected with the serotype III.

Orange and lemon peels were used for obtaining pectic polysaccharides. Citrus peels were previously treated with 96% ethanol, and the obtained alcohol-insoluble solids (AIS) were subjected to a sequential extraction with hot distilled water and hot 0.5% HCl. Water- and acid-extracted orange (WEOP and AEOP) and lemon (WELP and AELP) pectins were obtained. Acid extraction gave higher yields of pectin than water extraction and lemon peels were richer in pectin. Comparative investigations were carried out with chromatographically purified commercial citrus pectin (CPCP). Chemical and physicochemical characterization of all pectins was accomplished. It was found that pectins were similar in anhydrouronic acid content (AUАC, 69-81%), but differed in their degree of methylesterification (DM, 55-81%). Generally water-extracted pectins were with higher DM. Both orange pectins were with higher DM and degree of acetylation (DA, 2%), in comparison with the corresponding lemon pectins. Water-extracted pectins were with higher degree of feruloylation (DF, 0.12-0.34%). To our knowledge this is the first report on the estimation of ester-linked ferulic acid in orange and lemon peel pectins. Pectic polysaccharides differed in molecular weight and homogeneity. WELP was with the highest molecular weight and homogeneity. The pectins contained D-galacturonic and D-glucuronic acids, L-arabinose, D-galactose, L-fucose, L-rhamnose and D-xylose. All investigated pectins showed immunostimulating activity by complement activation in the classical pathway at 1.25 and 2.5 mg/mL. Pectic polysaccharides were modified with endopolygalacturonase. Enzyme-modified CPCP and WEOP had higher anti-complementary activity than the corresponding initial pectins.

Water-soluble and acid-soluble pectic polysaccharides with significant immunostimulating activity were isolated from alcohol-insoluble solids (AIS) of leek. Pectic polysaccharides characterized with high anhydrouronic acid content and common pectic sugars – L-arabinose, D-galactose, D-glucose, and L-rhamnose. It was accomplished that D-galactose content was the highest, which allowed the assumption that pectin sugar side chains were from galactan type. Enzyme modification of acid-extracted pectin was realized. Different pectin-degrading enzymes were used. The first modified pectic fraction, obtained after endopolygalacturonase action and alcohol precipitation contained rhamnogalacturonan I and had high D-galactose content. The second fraction obtained from the first, after β-galactosidase treatment characterized with low D-galactose content. Probably this was result from β-galactosidase hydrolysis of pectin side chains. It was proved by the action of β-galactosidase that galactan side chains were mainly composed of β-(1→4)-linked D-galactose. It was accomplished that rhamnogalacturonan I had higher immunostimulating activity than the initial pectic polysaccharide, which confirmed the statement that pectin hairy regions were responsible for the biological activity. The second fraction had lower D-galactose content and lower activity than the first. Probably galactan side chains were responsible for the immunostimulating activity.