Neonatal pig liver-derived progenitors for insulin-producing cells: an in vitro study.

Beta (beta)-cell replacement represents an attractive approach for the possible cure of type 1 insulin-dependent diabetes mellitus (IDDM). In a search for potential sources of insulin-secreting cells for IDDM substitution therapy, we have focused on the neonatal pig liver, which is putatively enriched in multipotent stem cells. We then isolated cells measuring 10 to 15 microm in diameter, identified as small cells, characterized by a high proliferation rate and positive staining for immature liver and pancreatic endocrine cell markers (i.e., insulin and pancreatic duodenal homeobox). The ability of these cells to transdifferentiate into pancreatic beta-like cells under culture conditions with exendin-4 (Ex-4) or high glucose concentration was examined. We observed that insulin secretion was not physiological in basal conditions, although it became responsive to glucose after 5 days of exposure to Ex-4. This beta-cell-like phenotype remained physiologically stable, even after stimulus withdrawal. Based on these observations, we contend that the proposed cell and tissue model might offer several advantages as a candidate for substitution cell therapy in IDDM, because the neonatal pig liver seems enriched in cells, with a mixed pancreas-liver phenotype, that are easier to purify and grow in culture and are more functional than other beta-like cells upon in vitro single short-term stimulation challenge.

Bcl-2 down modulation in WEHI-3B/CTRES cells resistant to Cholera Toxin (CT)-induced apoptosis.

The very different effects of Cholera Toxin (CT) on cell growth and proliferation may depend on the type of ganglioside receptors in cell membranes and different signal transduction mechanisms triggered, but other functions related to the drug resistance mechanisms can not be excluded. The effect of CT treatment on the "in vitro" clonogenicity, the Population Doubling Time (PDT), apoptosis, PKA activation and Bax and Bcl-2 expression was evaluated in WEHI-3B cell line and its CT-resistant subclone (WEHI-3B/CTRES). In WEHI-3B parental cells the dramatic accumulation of cAMP induced by CT correlated well with PKA activation, increased PDT value, inhibition of clonogenicity and apoptosis. H-89 treatment inhibited PKA activation by CT but did not protect the cells from apoptosis and growth inhibition. In WEHI-3B/CTRES no significant CT-dependent accumulation of cAMP occurred with any increase of PKA activity and PDT. In CT resistant cells (WEHI-3B/CTRES), Bcl-2 expression was down regulated by both CT or drug treatment (eg., ciprofloxacin, CPX) although these cells were protected from CT-dependent apoptosis but not from drug-induced apoptosis. Differently from other cell models described, down regulation of Bcl-2 is proved to be independent on cAMP accumulation and PKA activation. Our observations support the implication of cAMP dependent kinase (PKA) in the inhibition of WEHI-3B cells growth and suggest that, in WEHI-3B/CTRES, Bcl-2 expression could be modulated by CT in the absence of cAMP accumulation. Also in consideration of many contradictory data reported in literature, our cell models (of one sensitive parental cell strain and two clones with different uncrossed specific resistance to CT and CPX) provides a new and interesting tool for better investigating the relationship between the CT signal transduction mechanisms and Bcl-2 expression and function.

Relações entre valor de uso e parâmetros fitossociológicas em duas fitofisionomias de cerrado no município de Uberlândia, MG / Relationships between use value and phytosociological parameters in two cerrado phytophysiognomies in Uberlândia municipality

Este trabalho teve como objetivo analisar a relação entre os parâmetros fitossociológicos e o índice de valor de uso para as espécies presentes na comunidade arbóreo-arbustiva em duas fitofisionomias de cerrado no distrito de Miraporanga, município de Uberlândia ­ MG, a fim de se testar a hipótese da aparência ecológica. Para a amostragem da vegetação foi utilizado o método de quadrantes. Posteriormente, elaborou-se uma lista com os nomes populares das espécies encontradas, sendo indagado aos moradores da região através de entrevistas, questões referentes ao conhecimento e utilização das espécies. Foi calculado o índice de valor de uso para todas as espécies conhecidas pelos moradores. As vinte espécies apresentando os maiores índices de valor de uso foram correlacionadas com seus respectivos parâmetros de freqüência, densidade e dominância, tendo sido encontrado uma correlação moderada entre valor de uso e densidade (0,51) e valor de uso e frequência (0,49) para as espécies encontradas no fragmento de cerrado stricto sensu.

In this study our main goal was to analyse the relationship between phytosociological parameters and the use value index for plant species found in two cerrado phytophysiognomies in Miraporanga, a rural section of Uberlândia municipality in Minas Gerais state, in order to test the ecological appearance hypothesis. For vegetation sampling we applied the quadrat method. Afterwards, we created a list containing the vernacular names of all plant species found and then asked Miraporanga dwellers about usage and their knowledge on these plant species. We calculated the use value for all known plant species. The twenty plant species bearing the highest use value indexes were correlated to their frequency, density and dominance parameters. We found a moderate correlation between use value and density (0.51) and use value and frequency (0.49) for species found in cerrado stricto sensu remnant.

Educação ambiental e cultura: articulando mídia e conhecimento popular sobre plantas / Environmental education and culture: connecting media and popular knowledge about plants

O artigo fundamenta-se em reflexões advindas de uma pesquisa sobre as múltiplas possibilidades 'do fazer' educação ambiental, tendo como ponto de partida um estudo em etnobotânica que buscou conhecer e valorizar o conhecimento sobre plantas em distritos rurais da cidade de Uberlândia, em Minas Gerais, Brasil. A pesquisa foi realizada com crianças, jovens e pessoas da comunidade dos distritos de Tapuirama e Cruzeiro dos Peixotos mediante a utilização de diversas linguagens das mídias. As abordagens metodológicas se diferenciaram no percurso investigativo procurando adequar-se à realidade de cada distrito. A coleta de dados foi realizada por meio de diversas mídias visuais, como fotografia e vídeo. Estes instrumentos estavam presentes nas diferentes oficinas realizadas ao longo da pesquisa; na última, houve a produção coletiva do documentário Causos do Cerrado. O estudo fez interagir o local (tradição do conhecimento popular sobre as plantas) e o global (recursos tecnológicos empregados na produção midiática).

The article is based on reflections coming from research done on the multiple possibilities of 'practical' environmental education, taking, as starting point, a study on ethnobotany that sought to get to know and value popular knowledge about plants in rural districts of the city of Uberlândia, state of Minas Gerais, Brazil. The survey was conducted among children, youth, and people from the community of the districts of Tapuirama and Cruzeiro of Peixotos and used various media languages. Different methodological approaches were used in the course of the investigation in an attempt to adjust to the reality of each district. The data were collected using various visual media, such as photography and video. These tools were present in the different workshops held over the course of the research project; during the last one, there was the collective production of the documentary titled Causos do Cerrado (Stories of Savannah). The study brought interaction between local (the tradition of the folk knowledge on plants) and global (technological resources employed in media production).

Long-term cultured neonatal porcine islet cell monolayers: a potential tissue source for transplant in diabetes.

BACKGROUND: The restricted availability of cadaveric human donor pancreases mandates validation of possibly inexhaustible, alternative sources of insulin secretory cells in order to expand islet transplant for the therapy of insulin dependent diabetes mellitus (T1DM). METHODS: Neonatal pig pancreatic islets (NPI), isolated and purified by our method, were specially cultured until confluent cell monolayers were obtained. Expression of several beta-cell phenotype transcriptional factors, under glucose and other stimuli, were examined throughout 90 days of culture. RESULTS: High glucose concentration and glucagon-like peptide 1 (GLP-1) were associated with maintenance either of insulin secretory patterns from the incubated cell monolayers, or expression of transcriptional markers associated with beta-cell like phenotypes. CONCLUSION: Morphological and molecular expression of beta-cell markers and products from NPI cell monolayers seem to identify a novel and potentially powerful source of insulin producing cells that might fulfill transplant needs for insulin substitution therapy.

Grafts of microencapsulated pancreatic islet cells for the therapy of diabetes mellitus in non-immunosuppressed animals.

Pancreatic-islet-cell transplantation may reverse hyperglycaemia in diabetic recipients that undertake general pharmacological immunosuppression. A major challenge that remains is the need to avoid immunosuppression associated with the use of allogeneic or heterologous islet cells. In the present study we demonstrate the use of microencapsulation of cells using artificial biocompatible and permselective membranes prepared with alginic acid derivatives and polyamino acids. While characterization of the microcapsule constituent polymers continues to progress, other technical issues such as definition of the immunobarrier capacity, biocompatibility, size, shape and graft site have come into sharper focus. Assessment of microcapsules properties, in order to establish possible guidelines for fabrication of reproducible membranes, and results from both in vitro functional testing, and in vivo encapsulated-islet-transplant outcome in several animal models of diabetes are reported.