Magnesium oxide nanoparticles and their ecotoxicological effect on edaphic organisms in tropical soil.

The demand for food has intensified production in agricultural areas and stimulated the use of nanotechnology to develop new inputs, especially nanoparticle materials. In this new context, predicting the impact of using nanoparticles on non-target organisms becomes a necessary measure. The aim of this study was to evaluate the ecotoxicological potential of magnesium (Mg2+ ) added via magnesium oxide nanoparticles (MgO-NPs), magnesium oxide (MgO), and magnesium nitrate hexahydrate (Mg [NO3 ]2 ·6H2 O) incubated over time in tropical soil on earthworms (Eisenia andrei), springtails (Folsomia candida), and enchytraeids (Enchytraeus crypticus). Tests were conducted using a clay-textured Latossolo Vermelho distrófico (Oxisol), which received increasing doses of Mg2+ (0; 25; 50; 100; 200 and 400 mg kg−1 of soil) from the three sources tested added to the soil. Treated soil was incubated for 120 days in a room with controlled temperature and photoperiod, and the ecotoxicological tests were performed at 0, 60, and 120 days of incubation. Despite having caused reduction in the reproduction of F. candida at the incubation time 0, MgO-NPs showed a low toxic potential against the other species studied, with toxicity only at a higher dose of 50 mg Mg kg−1 when compared to the other sources of Mg2+ applied to the soil (MgO and Mg [NO3 ]2 ·6H2 O). Responses associated with incubation times showed that all magnesium sources tested have lower toxicity over incubation time.

Encapsulation of geranyl cinnamate in polycaprolactone nanoparticles.

Geranyl cinnamate is an ester derived from natural compounds that has excellent antibacterial properties but is susceptible to degradation in the presence of oxygen, light, heat, moisture and other aggressive agents, making it unstable. In this work, the encapsulation of geranyl cinnamate in polycaprolactone (PCL) nanoparticles and its antibacterial properties towards Escherichia coli and Staphylococcus aureus were investigated. PCL nanoparticles loaded with geranyl cinnamate were obtained by a miniemulsification/solvent evaporation technique resulting in spherical nanoparticles with an average diameter of 177.6 nm. TGA showed that geranyl cinnamate evaporation was retarded at 20 °C after encapsulation. Aqueous dispersions of geranyl cinnamate-loaded PCL nanoparticles stored at 4 °C presented good colloidal stability over 60 days. Minimum inhibitory concentration (MIC) tests showed that geranyl cinnamate was not released from the PCL nanoparticles in aqueous solution even after 72 h, requiring the use of a trigger (e.g. oil phase, lipase to degrade the polymer matrix) to release the active compound.

Carcinoma neuroendócrino cutâneo primário (Ca de Merkel): relato de 6 casos e revisäo da literatura / Cutaneous primary neuroendocrine carcinoma (Ca de Merkel): report of 6 case and review of literature

Os autores apresentam seis casos de carcinoma neuroendócrino primário cutâneo tratados na INCa-RJ no período de janeiro/1980 a dezembro/1993 e confirmados pela imunohistoquímica. O trabalho enfatiza a necessidade de confirmaçäo diagnóstica pelo uso deste método além de recomendar tratamento radical baseado na ressecçäo cirúrgica ampla acompanhada por esvaziamento linfático regional eletivo que poderá ser complementado ou näo pela radioterapia e ou pela quimioterapia.