Grażyna Tokajuk

Magnetic nanoparticles as a drug delivery system that enhance fungicidal activity of polyene antibiotics

This study was designed to assess the antifungal/anti-biofilm and hemolytic properties of two polyene antibiotics, amphotericin B (AMF) and nystatin (NYS), attached to the surface of magnetic nanoparticles (MNP) against clinical isolates of Candida species and human red blood cells, respectively. The developed nanosystems, MNP@AMF and MNP@NYS, displayed stronger fungicidal activity than unbound AMF or NYS. Synergistic activity was observed with a combination of polyenes and MNPs against all tested Candida strains. Nanosystems were more potent than unbound agents when tested against Candida strains in the presence of pus, and as agents able to prevent Candida biofilm formation. The observed inactivation of catalase Cat1 in Candida cells upon treatment with the nanosystems suggests that disruption of the oxidation-reduction balance is a mechanism leading to inhibition of Candida growth. The significant decrease of polyenes lytic activity against host cells after their attachment to MNPs surface indicates improvement in their biocompatibility.

Clinical evaluation of photodynamic therapy efficacy in the treatment of oral leukoplakia.

BACKGROUND The aim of the study was clinical evaluation of photodynamic therapy efficacy in the treatment of oral leukoplakia lesions. METHODS Twenty-three consecutive patients aged 21-79 were included to the study. In all patients 44 homogeneous, flat leukoplakia lesions were clinically diagnosed and confirmed histopathologically. Photodynamic therapy was performed with the use of Photolon(®) photosensitizer, containing 20% Chlorine-e6 and 10% dimethyl sulfoxide and a semiconductor laser, with power up to 300mW and a wavelength of 660nm. Ten illumination sessions were conducted with the use of superficial light energy density of 90J/cm(2). RESULTS At baseline the mean size of leukoplakia lesion was 6.5±5.10cm(2) while after photodynamic therapy 3±2.99cm(2). Significant reduction (on average by 53.8%) of leukoplakia lesions sizes was observed after therapy. Twelve (27.27%) lesions had been completely cured, 22 (50%) partially cured, although 10 (22.73%) lasted unchanged. The efficacy of PTD was comparable in women and men irrespective of age. There have been no adverse site effects during therapy noted. CONCLUSIONS Within the limits of the study it can be concluded that photodynamic therapy with the use of Chlorine-e6 can lead to considerable reduction of oral leukoplakia lesions size thus may be useful in clinical practice. However there is a need of further studies on larger number of cases and longer follow-up time.

Cytotoxicity evaluation of three light-cured dentin adhesive materials on human gingival fibroblasts, ex vivo

PURPOSE To evaluate the cytotoxic effects of three current light-cured dentin adhesives, in both uncured and post-cured conditions, on human gingival fibroblasts. MATERIAL AND METHODS The materials tested were Heliobond, Adper Single Bond 2 and Xeno V, which are characterized by various compositions and application procedures. Each agent, in volumes of 5 and 10 μL, was tested after polymerization, and those unpolymerized were diluted in DMEM to 10-3 and 10-5. The cytotoxicity of the adhesives was assessed on the basis of a test of cell viability in a culture of human gingival fibroblasts, with the use of tetrazolic salt (MTT assay). RESULTS The results showed that, among the adhesive/bonding systems tested, Xeno V was the least cytotoxic. There were statistically significant differences in cell survival between polymerized Xeno V, Adper Single Bond 2 and Heliobond in the amount of 5 μL as well as between the Xeno V and Adper Single Bond 2 in 10-5 dilutions. The tested adhesives were more toxic in the polymerized form than in the dilutions. Samples of 10 μL resulted in a lower survival percentage of fibroblasts compared to 5 μL. CONCLUSION All the tested adhesives demonstrated cytopathic effects towards human gingival fibroblasts, but varied in their cytotoxicity. This has clinical implications. Dentists should follow the rules of adhesive application, precisely dose them and not allow direct contact with the gums as, even after polymerization, adhesive agents exhibit potential cytotoxic activity.

Sporicidal activity of ceragenin CSA-13 against Bacillus subtilis

Spore-forming bacteria are a class of microorganisms that possess the ability to survive in extreme environmental conditions. Morphological features of spores assure their resistance to stress factors such as high temperature, radiation, disinfectants, and drying. Consequently, spore elimination in industrial and medical environments is very challenging. Ceragenins are a new class of cationic lipids characterized by a broad spectrum of bactericidal activity resulting from amphipathic nature and membrane-permeabilizing properties. To assess the impact of ceragenin CSA-13 on spores formed by Bacillus subtilis (ATCC 6051), we performed the series of experiments confirming that amphipathic and membrane-permeabilizing properties of CSA-13 are sufficient to disrupt the structure of B. subtilis spores resulting in decreased viability. Raman spectroscopy analysis provided evidence that upon CSA-13 treatment the number of CaDPA-positive spores was clearly diminished. As a consequence, a loss of impermeability of the inner membranes of spores, accompanied by a decrease in spore resistance and killing take place. In addition to their broad antimicrobial spectrum, ceragenins possess great potential for development as new sporicidal agents.

New endodontic obturation systems and their interfacial bond strength with intraradicular dentine – ex vivo studies

PURPOSE To comparatively evaluate adhesive properties of selected root canal fillings through the measurement of the material-dentine interfacial bond strength. MATERIAL AND METHODS Fifty extracted single-rooted human teeth with one canal each were prepared using Hero instruments to size 30.04. Teeth were divided into four subgroups depending on the root canal filling material and the method of obturation: Resilon/Epiphany - a thermoplastic method (IA), Resilon/Epiphany - a matching single-point method (IB), gutta-percha/Roeko Seal Automix - a thermoplastic method (IIA) and gutta-percha/Roeko Seal Automix - a matching single-point method (IIB). The obturated roots were cut perpendicular to the long axis to create 1.7 mm thick slices. The bond strength was measured for each test slice with push -out testing machine. RESULTS The highest push-out bond strength was registered in subgroup IB (3.98 ± 1.33 MPa). Significantly lower bond strength was observed in subgroups IA (0.50 ± 0.24 MPa), IIA (0.33 ± 0.18 MPa) and IIB (0.08 ± 0.03 MPa) (p<0.001). No statistically significant differences in material-dentine interfacial bond strength values were observed between IA and IIA, IA and IIB, IIA and IIB subgroups (p > 0.05). CONCLUSIONS The push-out bond strength of the material-dentine interface was dependent on the type of material used and the root canal filling technique. The R/E system exhibited better adhesion ability to intraradicular dentine than G/RSA. The highest bond strength was observed for Resilon/Epiphany introduced with the single-cone technique.

The Role of Oral Cavity Biofilm on Metallic Biomaterial Surface Destruction–Corrosion and Friction Aspects

Metallic biomaterials in the oral cavity are exposed to many factors such as saliva, bacterial microflora, food, temperature fluctuations, and mechanical forces. Extreme conditions present in the oral cavity affect biomaterial exploitation and significantly reduce its biofunctionality, limiting the time of exploitation stability. We mainly refer to friction, corrosion, and biocorrosion processes. Saliva plays an important role and is responsible for lubrication and biofilm formation as a transporter of nutrients for microorganisms. The presence of metallic elements in the oral cavity may lead to the formation of electro-galvanic cells and, as a result, may induce corrosion. Transitional microorganisms such as sulfate-reducing bacteria may also be present among the metabolic microflora in the oral cavity, which can induce biological corrosion. Microorganisms that form a biofilm locally change the conditions on the surface of biomaterials and contribute to the intensification of the biocorrosion processes. These processes may enhance allergy to metals, inflammation, or cancer development. On the other hand, the presence of saliva and biofilm may significantly reduce friction and wear on enamel as well as on biomaterials. This work summarizes data on the influence of saliva and oral biofilms on the destruction of metallic biomaterials.

Formulation and candidacidal activity of magnetic nanoparticles coated with cathelicidin LL-37 and ceragenin CSA-13

Fungal infections caused by Candida spp. represent an emerging problem during treatment of immunocompromised patients and those hospitalized with serious principal diseases. The ever-growing number of fungal strains exhibiting drug resistance necessitates the development of novel antimicrobial therapies including those based on membrane-permeabilizing agents and nanomaterials as drug carriers. In this study, the fungicidal activities of LL-37 peptide, ceragenin CSA-13 and its magnetic derivatives (MNP@LL-37, MNP@CSA-13) against laboratory and clinical strains of C. albicans, C. glabrata and C. tropicalis were evaluated. These experiments confirm the high anti-fungal activity of these well-characterized agents mediated by their interaction with the fungal membrane and demonstrate elevated activity following immobilization of LL-37 and CSA-13 on the surface of magnetic nanoparticles (MNPs). Furthermore, MNP-based nanosystems are resistant to inhibitory factors present in body fluids and effectively inhibit formation of fungal biofilm. Simultaneously, synthesized nanostructures maintain immunomodulatory properties, described previously for free LL-37 peptide and CSA-13 substrate and they do not interfere with the proliferation and viability of osteoblasts, confirming their high biocompatibility.

Use of magnetic nanoparticles as a drug delivery system to improve chlorhexidine antimicrobial activity

Nanotechnology offers new tools for developing therapies to prevent and treat oral infections, particularly biofilm-dependent disorders, such as dental plaques and endodontic and periodontal diseases. Chlorhexidine (CHX) is a well-characterized antiseptic agent used in dentistry with broad spectrum activity. However, its application is limited due to inactivation in body fluid and cytotoxicity toward human cells, particularly at high concentrations. To overcome these limitations, we synthesized nanosystems composed of aminosilane-coated magnetic nanoparticles functionalized with chlorhexidine (MNP@CHX). In the presence of human saliva, MNPs@CHX displayed significantly greater bactericidal and fungicidal activity against planktonic and biofilm-forming microorganisms than free CHX. In addition, CHX attached to MNPs has an increased ability to restrict the growth of mixed-species biofilms compared to free CHX. The observed depolarization of mitochondria in fungal cells treated with MNP@CHX suggests that induction of oxidative stress and oxidation of fungal structures may be a part of the mechanism responsible for pathogen killing. Nanoparticles functionalized by CHX did not affect host cell proliferation or their ability to release the proinflammatory cytokine, IL-8. The use of MNPs as a carrier of CHX has great potential for the development of antiseptic nanosystems.

Cytological picture of the oral mucosa in patients with gastric and colon cancer

The incidence of malignant gastrointestinal cancers in Poland has been constantly growing, which has led to an intensification of the search for new markers of the early clinical stage of this disease. The oral cavity, as the first part of the gastrointestinal tract, has a very important role. The oral cavity presents symptoms of both typically stomatological and systemic diseases. Oral cancers, benign or malignant, may originate and grow in any of the tissues of the mouth, and within this small area they may be of varied clinical, histological and biological features. These can be lesions typically observed in the oral cavity, but also characteristic of cases where the symptoms occur both in the mouth and in other body parts. The aim of this study was to present a cytological picture of the oral mucosa in patients with gastric and colon cancer and to compare the cytological picture with that obtained from a group of patients with no cancer, using the Papanicolaou classification and the Bethesda system. The study was conducted in 126 patients treated surgically in the II General and Gastroenterological Surgery Clinic between 2006 and 2008. All patients were divided into two groups based on the type of lesions. In both of the studied groups, more than half of the patients did not present any abnormalities in the mucosa of the mouth, lips and cheeks in the physical examination. None of the patients had erosion, ulceration or lesions typical of leukoplakia or lichen planus. No malignant cells were detected in either of the studied groups, and there were no well-defined lesions found in the oral cavity that would distinguish the patients with gastrointestinal cancer. (

Histone deacetylases affect transcriptional regulation of CCL2 and CXCL8 expression by pulmonary fibroblasts in vitro

INTRODUCTION Chemokines have been shown to play an important role in tissue remodeling and fibrosis in the respiratory system. In this study we wanted to evaluate the mechanisms, which regulate the expression of selected chemokines by pulmonary fibroblasts in vitro. MATERIAL AND METHODS Pulmonary fibroblasts were cultured with and without bacterial lipopolysaccharide (LPS) for 6 hours. In addition some of the cultures were pre-treated with histone deacetylase inhibitor Trichostatin A (TSA). Real-time PCR reaction was performed to estimate the expression of chemokines CCL2, CCL3 and CXCL8. RESULTS In unstimulated cultures detectable expression of CCL2 and CXCL8 was observed, while CCL3 expression could not be detected. After stimulation with LPS, TSA and both agents together CCL2 expression rose by 1.52, 1.62 and 1.8 times in comparison to control cultures respectively. CXCL8 mRNA expression levels after stimulation with LPS, TSA and LPSTSA increased by 1.53, 1.91 and 2.4 times accordingly. CONCLUSION Epigenetic mechanisms related to histone acetylation affects transcriptional regulation of CCL2 and CXCL8 expression by pulmonary fibroblasts. Those mechanisms may play a role in tissue repair and pathologic remodeling.