Responses of human hepatoma HepG2 cells to silver nanoparticles and polycyclic aromatic hydrocarbons

The nanotechnology has revolutionized the global market with silver nanoparticles (AgNP) occupying a prominent position due to their remarkable anti-bacterial properties. However, there is no data about the adverse and toxic effects of associations of AgNP and ubiquitous compounds, such as polycyclic aromatic hydrocarbons (PAH). In the current study, we investigated the responses of HepG2 cells to realistic concentrations of AgNP (0.09, 0.9, and 9?ng ml^?1) and mixture of PAH (30 and 300?ng ml^?1), separately and in association. Cell viability and cytotoxicity (neutral red retention and MTT production assays) and proliferation (crystal violet [CV] assay), xenobiotic efflux transporter activity (rhodamine B accumulation assay), ROS levels (dichlorodihydrofluorescein diacetate assay), and lipid peroxidation (pyrenylphosphine-1-diphenyl assay) were analyzed. There was no decreases of cell viability after exposure to AgNP, PAH and most of AgNP?+?PAH associations, but increases of cell viability/number (CV assay) occurred. Efflux transporter activity was not affected, with exception of one AgNP?+?PAH associations, ROS levels increased, but lipid peroxidation decreased. Some toxicological interactions occurred, particularly for the highest concentrations of AgNP and PAH, but there is no evidence that these interactions increased the toxicity of AgNP and PAH.     

In vivo tumor imaging using a novel RNAi-based detection mechanism

A new concept of tumor imaging is introduced using a siRNA-based probe that is capable of amplifying a specific endogenous fluorescence emission in cancerous tissue. In previous studies, we demonstrated a significant downregulation of Ferrochelatase (FECH) mRNA-expression in colorectal carcinomas leading to the accumulation of protoporphyrin IX (PpIX), a fluorescent metabolite of the heme synthesis. In this article, we report on first in vivo experiments in xenografted nude mice using folate-coupled liposomes or dendritic polyglycerolamine nanoparticles carrying ferrochelatase-siRNA to enhance PpIX-derived fluorescence in the tumor tissue. Tiny tumor foci could be monitored by the emission of PpIX fluorescence in vivo. Due to the omnipresence of the heme synthesis pathway, targeted application of ferrochelatase-siRNA may provide a general means for molecular imaging.From the Clinical EditorA new concept of tumor imaging is presented in this paper using a siRNA-based probe detecting protoporphyrin IX (PpIX), a fluorescent metabolite of the heme synthesis previously demonstrated to accumulate in cancer tissue.     

Patterns of Use of Induction Therapy for T2N0 Esophageal Cancer

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On the photodegradation of azithromycin,erythromycin and tylosin and their transformation products – A kinetic study

In this study, the photo-induced degradation of azithromycin (Azi), erythromycin (Ery) and tylosin (Tyl) was investigated. The three macrolides are regularly found in different kinds of water, and are thus considered a potential environmental risk. In search of efficient ways for elimination, the compounds were systematically irradiated with a polychromatic UVC light source emitting 185, 254 and discretely further up to 580 nm. Due to their specific structural features, the macrolides possess different optical absorption characteristics leading to photodegradation pathways with dissimilar kinetic properties. Hence, the photodegradation products and their kinetics were analyzed using high-performance liquid chromatography (HPLC) coupled to high-resolution time-of-flight mass spectrometry. Among the degradants, i.e. the products formed during UV irradiation, both sugar moieties and lactone macrocycles were observed. Applying a first order kinetic model, the half-life of Azi was determined as 1.0?3.7 min, that of Ery as 1.0?14.2 min depending on the reaction conditions. The two compounds possess much lower absorption cross-sections than Tyl, in particular at 254 nm. Their half-lives appeared at least three times higher than that of Tyl that has t_1/2 of 0.2?1.0 min. Based on quantum efficiency considerations, it was assumed that the degradation of Ery and Azi was mainly due to hydroxyl radical formation, which originated from water irradiation below 200 nm, whereas Tyl experienced predominantly photo induced degradation. The photodegradants of Azi exhibited half-lives of over 200 min, whereas most of the photo-products of Ery and Tyl showed half-lives of less than 10 min. Photodegradation processes were investigated at pH 3, pH 7 and pH 9 and in the presence of hydrogen peroxide. Both the educts and the photo-products were degraded more rapidly under neutral and acid conditions.