Chitosan and cellulose-based composite hydrogels with embedded titanium dioxide nanoparticles as candidates for biomedical applications.

Hydrogel based matrices and titanium dioxide (TiO2) nanoparticles (NPs) are well established materials in bone tissue engineering. Nevertheless, there is still a challenge to design appropriate composites with enhanced mechanical properties and improved cell growth. Progressing in this direction, we synthesized nanocomposite hydrogels by impregnating TiO2 NPs in a chitosan and cellulose-based hydrogel matrix containing polyvinyl alcohol (PVA), to enhance the mechanical stability and swelling capacity. Although, TiO2 has been incorporated into single and double component matrix systems, it has rarely been combined with a tri-component hydrogel matrix system. The doping of NPs was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy and small- and wide-angle X-ray scattering. Our results showed that incorporation of TiO2 NPs improved the tensile properties of the hydrogels significantly. Furthermore, we performed biological evaluation of scaffolds, swelling degree, bioactivity assessment, and hemolytic tests to prove that all types of hydrogels were safe for use in the human body. The culturing of human osteoblast-like cells MG-63 on hydrogels showed better adhesion of cells in the presence of TiO2 and showed increasing proliferation with increasing amount of TiO2. Our results showed that the sample with the highest TiO2 concentration, CS/MC/PVA/TiO2 (1 %) had the best biological properties.

Predictive Significance of Thymidylate Synthase Expression in Non-small Cell Lung Cancer.

BACKGROUND/AIM: To date, many studies have suggested that thymidylate synthase (TS) could be used as a prognostic and predictive marker in non-small cell lung cancer (NSCLC) patients. However, results have been contradictory. The aim of this study was to evaluate TS mRNA levels in tumor tissue of NSCLC patients who underwent complete surgical resection and to analyze its prognostic and predictive potential. MATERIALS AND METHODS: The study group consisted of 64 patients who underwent curative lung resection. Paired lung tissue samples were taken directly from the tumor tissue and from adjacent, histologically cancer-free lung tissue. The quantitative estimation of TS expression was performed by reverse transcription real-time polymerase chain reaction (RT-qPCR). The relationship between TS expression level and disease-free interval (DFI) and overall survival (OS) was analyzed. RESULTS: There was significantly higher TS expression in NSCLC tumor tissue comparing to normal lung tissue. In the group of patients who received adjuvant chemotherapy based on platinum derivatives in combination with paclitaxel or gemcitabine, we found shorter DFI (p=0.0473) and OS (p=0.0053) in those with high expression of TS. CONCLUSION: Our results demonstrated the relationship of high tumor tissue TS levels to adverse prognosis in patients undergoing adjuvant chemotherapy. TS is a non-specific tumor marker with respect to NSCLC, therefore we think that its best use would be as a member of the panel of predictors of adjuvant treatment efficacy.