Evaluation of extruded starch foam for glucose-supplying biomaterials.

The survival rate of mesenchymal stem cells (MSC), a crucial factor in tissue engineering, is highly dependent on glucose supply. The purpose of this paper is to study the potential of starch foams as glucose suppliers. It is investigated through in vitro hydrolysis by amyloglucosidase in conditions that respect physiological constraints (37 °C and pH 7.4), including a duration of 21 days, and no stirring. Nine extruded starch foams with amylose contents ranging from 0 to 74 %, with various cell wall thicknesses (50 to 300 µm), and different crystallinities (0-30 %) were hydrolysed. These kinetics were fitted by a model which shows that the maximum rate of hydrolysis varies from 7 to 100 %, and which allows the rate of hydrolysis at 21 days to be calculated precisely. The results reveal the major role of amylose in glucose delivery kinetics, and the secondary roles of crystallinity and cell wall thickness of the foams. Additional hydrolysis of starch films revealed that thickness positively influences the amylose chain reorganisation during hydrolysis, which, in slows down and limits glucose delivery. A simple glucose delivery kinetics analysis procedure is proposed to select samples for testing as MSC glucose suppliers.

Introducao de um metodo rapido e simples para a determinacao de imunecomplexos circulantes em neoplasias:correlacao com o progresso da doenca. / A rapid and simple method for the determination of circulating immune complexes in neoplasms: correlation with the course of the disease

No presente trabalho os autores introduzem um metodo rapido, simples e sensivel de quantificacao de imunecomplexos circulantes no soro de individuos normais e em pacientes portadores de neoplasias solidas. Elevacoes significativas foram encontradas em pacientes portadores de neoplasias, quando comparados com aqueles observados em individuos normais, e comparavel a valores observados em pacientes portadores de colagenoses. Sao discutidas as aplicacoes deste ensaio e demonstradas as correlacoes com a presenca de massa tural localizada ou disseminada