BackgroundNanocomposites produced by reinforcement of polysaccharide matrix with nanoparticles are widely used in engineering of biomaterials. However, clinical applications of developed novel biomaterials are often limited due to their poor biocompatibility.PurposeThe aim of this work was to comprehensively assess biocompatibility of highly macroporous chitosan/agarose/nanohydroxyapatite bone scaffolds produced by a novel method combining freeze-drying with a foaming agent. Within these studies, blood plasma protein adsorption, osteoblast (MC3T3-E1 Subclone 4 and hFOB 1.19) adhesion and proliferation, and osteogenic differentiation of mesenchymal stem cells derived from bone marrow and adipose tissue were determined. The obtained results were also correlated with materials' surface chemistry and wettability to explain the observed protein and cellular response.ResultsObtained results clearly showed that the developed nanocomposite scaffolds were characterized by high biocompatibility and osteoconductivity. Importantly, the scaffolds also revealed osteoinductive properties since they have the ability to induce osteogenic differentiation (Runx2 synthesis) in undifferentiated mesenchymal stem cells. The surface of biomaterials is extremely hydrophilic, prone to protein adsorption with the highest affinity toward fibronectin binding, which allows for good osteoblast adhesion, spreading, and proliferation.ConclusionProduced by a novel method, macroporous nanocomposite biomaterials have great potential to be used in regenerative medicine for acceleration of the bone healing process.

IntroductionSelf-medication can contribute to the inappropriate use of antibiotics in respiratory tract infections (RTI). This phenomenon has not been well described, particularly in Poland. The aim of our study was to describe the prevalence of antibiotic self-medication for RTI, to explore factors influencing antibiotic use without prescription, and to determine the available sources of such antibiotics.Material and methodsA self-administered questionnaire completed by patients presenting to family medicine clinics at Lodz and Wroclaw from 1st March to 15th May 2010.ResultsA total of 891 patients in ten clinics completed the survey (response rate, 89.1%). Overall, 41.4% (n = 369) of patients reported self-medication with an antibiotic for RTI. The most common reason for antibiotic self-medication was a belief that antibiotics treat the majority of infections, including influenza and influenza-like illnesses (43.9%; n = 162). The predominant sources of antibiotics for self-medication were antibiotics from previous prescriptions stored by the patient at home (73.7%, n = 272), those received from a pharmacy without prescription (13.5%; n = 50), or from family members and friends (12.7%; n = 47).ConclusionsAntibiotic self-medication for RTI was common in this population. This may be due to the belief that the antibiotics treat the majority of infections. A recommendation to either ask patients to return unused antibiotics to the physician's office or to dispense antibiotics in the exact amount which is necessary for an individual course, as well as the targeted education of pharmacy personnel and the general population, appear to be justified.

Intratracheal instillation serves as a model for inhalation exposure. However, for this, materials are dispersed in appropriate media that may influence toxicity. We tested whether different intratracheal instillation dispersion media influence the pulmonary toxicity of different nanomaterials. Rodents were intratracheally instilled with 162 µg/mouse/1620 µg/rat carbon black (CB), 67 µg/mouse titanium dioxide nanoparticles (TiO2) or 54 µg/mouse carbon nanotubes (CNT). The dispersion media were as follows: water (CB, TiO2); 2% serum in water (CB, CNT, TiO2); 0.05% serum albumin in water (CB, CNT, TiO2); 10% bronchoalveolar lavage fluid in 0.9% NaCl (CB), 10% bronchoalveolar lavage (BAL) fluid in water (CB) or 0.1% Tween-80 in water (CB). Inflammation was measured as pulmonary influx of neutrophils into bronchoalveolar fluid, and DNA damage as DNA strand breaks in BAL cells by comet assay. Inflammation was observed for all nanomaterials (except 38-nm TiO2) in all dispersion media. For CB, inflammation was dispersion medium dependent. Increased levels of DNA strand breaks for CB were observed only in water, 2% serum and 10% BAL fluid in 0.9% NaCl. No dispersion medium-dependent effects on genotoxicity were observed for TiO2, whereas CNT in 2% serum induced higher DNA strand break levels than in 0.05% serum albumin. In conclusion, the dispersion medium was a determinant of CB-induced inflammation and genotoxicity. Water seemed to be the best dispersion medium to mimic CB inhalation, exhibiting DNA strand breaks with only limited inflammation. The influence of dispersion media on nanomaterial toxicity should be considered in the planning of intratracheal investigations.

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The present work demonstrates a simple and low-cost method to produce bulk quantities of graphene material through the thermal treatment of graphite oxide (GO).