Cell uptake and oral absorption of titanium dioxide nanoparticles.

Large efforts are invested on the development of in vitro tests to evaluate nanomaterial (NM) toxicity. In order to assess the relevance of the adverse effects identified in in vitro toxicity tests a thorough understanding of the biokinetics of NMs is critical. We used different in vitro and in vivo test methods to evaluate cell uptake and oral absorption of titanium dioxide nanoparticles (TiO2 NPs). These NPs were readily uptaken by A549 cells (carcinomic human alveolar basal epithelial cells) in vitro. Such rapid uptake contrasted with a very low oral absorption in a differentiated Caco-2 monolayer system (human epithelial colorectal adenocarcinoma cells) and after oral gavage administration to rats. In this oral study, no significant increase in the levels of titanium was recorded by ICP-MS in any of the tissues evaluated (including among other: small intestine, Peyer's patches, mesenteric lymph nodes, liver, and spleen). No NPs were observed by TEM in sections of the small intestine, except for several particles in the cytoplasm of a cell from a Peyer's Patch area. The observation of NPs in Peyer's Patch suggests that the Caco-2 monolayer system is likely to underestimate the potential for oral absorption of NPs and that the model could be improved by including M-cells in co-culture.

[Retained rectal foreign bodies by trans-anal introduction. Case report]. / Corpi estranei endorettali introdotti per via anale. Case report.

The Authors refer about two cases of retained rectal foreign bodies by trans-anal introduction as consequence of anal eroticism: a deodorant aerosol-can cap and a sizeable phallic object. These reports represent an occasion to talk about the etiology (the wide variety of foreign bodies) and the motivations (eroticism or sadism, clumsy diagnostic and therapeutic procedures, true or presume accidents) responsible for this pathological condition and to consider every therapeutic options employed during the past years, without forgetting that, despite difficulties, non-surgical extraction is to prefer, if possible, because of the negative prognostic implications often related to the surgical treatment. The Authors finally confirm, because of the severity of this pathological condition - with negative outcomes especially in that cases with complete or incomplete perforative complications (produced during introduction through the anus or during several attempts of extraction of the object or caused by its long staying in the rectum because of the patient's denial of medical care) - the surgeons can't put aside possible indication for surgical treatment.