Cyanobacteria are common members of the freshwater microbiota in lakes and drinking water reservoirs, and are responsible for several cases of human intoxications in Brazil. Pseudanabaena galeata and Geitlerinema splendidum are examples of the toxic species that are very frequently found in reservoirs in Sao Paulo, which is the most densely populated area in Brazil. In the search for toxic strains collected from water reservoirs and maintained in the Cyanobacterial Culture Collection (CCIBt) of the Institute of Botany of Brazil, the acetic acid extracts (AE) of P. galeata CCIBt 3082 and G. splendidum CCIBt 3223 were analyzed by planar chromatography, which indicated the absence of cyanotoxins. Animal tests were then carried out, and both extracts were found to induce toxic effects in mice when administered intraperitoneally. The present study aimed to investigate whether the oral ingestion of the above mentioned cyanobacteria extracts would also induce toxic effects in mice. Necropsy and histopathological studies were conducted using tissue samples from the animals, which were euthanized one week after the administration of the extracts. The AE of P. galeata did not cause death but did induce transient symptoms, including eyebrow ptosis, straub tail, and pain. The euthanized animals presented hemorrhage in the liver, whereas the histological analysis showed disorganization of the hepatic parenchyma, necrosis, hyperemia, and proximity of the centrilobular vein in the liver. In addition, alterations in the convoluted tubules of the kidneys were observed, and the lungs were unaffected. The AE of G. splendidum caused only one death, and induced transient symptoms, such as dyspnea, paralysis, and pain, in the other mice. The necropsy of the euthanized mice showed hemorrhage in the lungs and liver. The lungs presented hemorrhagic focuses, alveolar collapse, and granulomatous foci. The liver presented hemorrhagic and enlarged sinusoids, hyperemia, proximity of the centrilobular vein, and disorganization of the hepatic parenchyma. Some areas also exhibited an inflammatory infiltrate and calcified tissue inside blood vessels. Necrosis and rupture of the convoluted tubule cells were observed in the kidneys. Further analysis of the both extracts indicated the lack of hemolytic activity, and the presence of two unknown anti-AChE substances in the AE of G. splendidum. Thus, P. galeata and G. splendidum are producers of novel toxins that affect mammals when administered orally.

Stem cells are capable of generating various cell lines and can be obtained from adult or embryonic tissues for clinical therapies. Stem cells from deciduous dental pulp are among those that are easily obtainable from adult tissues and have been widely studied because of their ability to differentiate into a variety of cell lines in the presence of various chemical mediators. We have analyze the expression of several proteins related to the differentiation and proliferative potential of cell populations that compose the tooth germ of human fetuses. We evaluate 20 human fetuses of both genders. After being paraffin-embedded, cap and bell stages of tooth germ development were subjected to immunohistochemistry for the following markers: Oct-4, Nanog, Stat-3 and Sox-2. The studied antibodies showed nuclear or cytoplasmic immunnostaining within various anatomical structures and with various degrees of expression, indicating the action of these proteins during tooth development. We conclude that the interrelationship between these transcription factors is complex and associated with self-renewal and cell differentiation. Our results suggest that the expression of Oct-4, Nanog, Sox-2 and Stat-3 are related to differentiation in ameloblasts and odontoblasts.

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Conditioned medium (CM) (cell secretome) is a cocktail of growth factors, cytokines, and other soluble mediators secreted by cells into a culture medium. These growth factors are fundamental in many cellular processes such as cell growth, differentiation, and others and the composition of these factors is individual for each cell type. Osteoclasts are large multinucleated cells that are responsible for bone resorption. Immune and cancer cells are known to produce different growth factors, which are able to induce or inhibit osteoclast differentiation. Herein, we evaluated the effect of CM obtained from the supernatant of activated and non-activated Jukart-E6 cells, as well as from one murine (B16-F10) and one human melanoma cell line (SKMEL28). To induce osteoclast differentiation, murine bone marrow mononuclear cells were cultured in the presence and absence of differentiation factors (DF), such as macrophage colony-stimulating factor, prostaglandin E2, receptor activator of nuclear factor-κB ligand, and CM. We measured the concentration of interleukin 6, tumor necrosis factor-α and interferon γ (IFN-γ) in CM that can inhibit or induce osteoclastogenesis. Our study demonstrated that CM obtained from each cell line suppresses or inhibits osteoclasts formation at early and intermediate stages of differentiation in the absence or presence of DF. CM obtained from activated Jurkat-E6 cells demonstrates a stronger effect when compared with CM from naïve Jurkat-E6 cells or human and murine melanoma cells. Moreover, CM obtained from activated Jurkat-E6 cells shows higher secretion of IFN-γ, which is an inhibitor of osteoclastogenesis, in comparison with CM obtained from the three other cell lines. On the other hand, CM derived from B16-F10 cells showed a smaller inhibitory effect when compared with CM derived from the other cells. myristate acetate; RANK, receptor activator of nuclear factor kappa-B; RANKL, receptor activator of nuclear factor kappa-B ligand; RPMI, Roswell Park Memorial Institute Medium; TMB, 3,3′,5,5′-tetramethylbenzidine liquid substrate system; TNF-α, tumor necrosis factor-α; TRAF 6, TNF receptorassociated factor 6; TRAP, tartrate-resistant acid phosphatase; α-MEM, α-minimum essential medium.Nicole C. Mambelli-Lisboa and Eduardo O. Frare contributed equally to this work.Osteoclastogenesis suppression using conditioned media N. C. Mambelli-Lisboa et al.

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