In vitro genotoxicity assessment and comparison of cerium (IV) oxide micro- and nanoparticles.

Cerium (IV) oxide (CeO2), which is used as a biomaterial, has wide application in areas such as the biomedical, glass polishing, electronic, automotive, and pharmacology industries. Comparing with the literature, in this study, the genotoxic effects of cerium (IV) oxide microparticles (COMPs) and cerium (IV) oxide nanoparticles (CONPs) were investigated for the first time in human peripheral blood cultures at concentrations of 0.78, 1.56, 3.125, 6.25, 12.5, 25, and 50 ppm for 72 h under in vitro conditions. Particle sizes of COMPs and CONPs were determined using scanning electron microscopic analysis. Micronucleus and chromosome aberration tests were used to determine the genotoxicity of COMPs and CONPs. The average particle sizes of COMPs and CONPs were approximately 148.25 and 25.30 nm, respectively. It was determined that CeO2 particles in both micro and nano sizes were toxic at all concentrations compared to the negative control group (distilled water). Importantly, COMPs and CONPs were genotoxic even at the lowest concentration (0.78 ppm). Comparing particle sizes, the data indicated that COMPs were more toxic than CONPs. The results suggest that genotoxicity of COMPs and CONPs may be a function of applied concentrations and particle sizes.

[Evaluation of Histological Response in Chronic Hepatitis B Patients with Tenofovir or Entecavir Therapy]. / Tenofovir veya Entekavir Tedavisi Alan Kronik Hepatit B Hastalarinda Histolojik Yanitlarin Degerlendirilmesi.

Chronic hepatitis B (CHB) is an important public health problem in the world and Turkey. The aim of this study was to evaluate the histological, virological, serological and biochemical response rates in CHB patients receiving tenofovir or entecavir therapy. Control liver biopsies were performed on patients who received tenofovir or entecavir therapy for one year or longer. Histopathological grading was scored according to the modified Knodell system. Eighty-seven CHB patients were included in this study, 56 patients were receiving tenofovir and 31 patients were receiving entecavir therapy. Patients in two treatment groups were similar in terms of baseline parameters (p> 0.05). At the end of the treatment, there was a significant decrease in mean values of HBV DNA, alanine aminotransferase and necroinflammatory scores for both groups (p<0.001); however, no statistically significant change was observed in fibrosis scores (p> 0.05). Histological responses were obtained 66.1% from the tenofovir group and 54.8% from the entecavir group. Treatment with tenofovir and entecavir resulted with improvement in Ishak fibrosis scores in 12.5% and 12.9% of the patients, respectively. For 14.3% of the tenofovir-treated patients and for 22.6% of the entecavir-treated patients, the Ishak fibrosis scores worsened. Baseline intermediate/ advanced fibrosis stage (Ishak fibrosis score: 3-6) was found as independent determinant factor on histological response and improvement of fibrosis score (OR= 3.99, p= 0.01; OR= 31.67, p= 0.002; respectively) and treatment duration longer than five years is an independent determinant for improvement of necroinflammatory score (OR= 5.79, p= 0.02). There was no significant difference in the virological, serological, biochemical and, histological responses and improvement of necroinflammatory and fibrosis scores between tenofovir and entecavir groups (p> 0.05). Similar histological, virological, serological and biochemical responses were obtained in patients with CHB receving tenofovir and entecavir treatments. Further studies involving a large number of patients receiving long-term therapy should be done to understand the effects of antiviral treatments on healing of liver histology.