Efeito do flúor presente no fosfato de rocha de Araxá sobre a produção hepática de AMP-cíclico em frangos de corte

ABSTRACTThe cyclic adenosine 3’, 5’-monophosphate (cAMP) production was evaluated in liver thin sections of broiler chicks fed on a experimental diet containing bicalcium phosphate or Araxá rock phosphate (ARP) as source of P, with a high content of fluorine, at different ages: from the first to the 42nd and from the 21st to the 42nd day of age. The intake of the ARP formulated diet starting from birth elicited an increase of cAMP production in broiler liver. However, when this diet was offered after the 21st day of age, the hepatic cAMP production in broilers was not significantly (P>0.05) affected, suggesting that the effect of high fluorine present in Araxá rock phosphate, on hepatic cAMP of broiler chicks depends on the age in which the experimental diet is started. _______________________________________________________________________________ RESUMOA produção de adenosina 3’, 5’- monofosfato cíclico (AMPc) foi avaliada em fatias de fígado de frangos de corte que receberam dieta experimental contendo fosfato bicálcico ou fosfato de rocha de Araxá, com alto teor de flúor, como fonte de fósforo, em dois períodos distintos: do 1º ao 42º e do 21º ao 42º dias de idade. A ingestão da dieta formulada com fosfato de rocha de Araxá desde o 1º dia de vida, provocou elevação da produção de AMPc no fígado dos frangos de corte. Entretanto, a utilização da mesma dieta a partir do 21º de idade não alterou significativamente (P>0,05) a produção hepática de AMPc nas aves, sugerindo que a influência da alta ingestão do flúor presente no fosfato de rocha de Araxá sobre o AMPc hepático dos frangos de corte é dependente da idade em que a administração da dieta é iniciada

Preparation and biocompatibility of poly (methyl methacrylate) reinforced with bioactive particles

Calcium phosphates and bioactive glasses have been used in many biomedical applications for more than 30 years due basically to their bioactive behavior. However, ceramics are too brittle for applications that require high levels of toughness and easy processability. In this work, a biphasic calcium phosphate (BCP) and a bioactive glass composition (BG) were combined with polymers to produce composites with tailorable properties and processability. The BCP particles were synthesized by a precipitation technique. The BG particles were produced by sol-gel processing. The BCP particles were treated with a silane agent to improve the compatibility between particles and the polymer matrix. Dense samples were produced by hot pressing (200 °C) a mixture of 30 wt.% of particles in poly (methyl methacrylate). The samples produced were characterized by X-ray diffraction, infrared spectroscopy and scanning electron microscopy. Mechanical properties were evaluated by a three point bending test. Samples were also submitted to in vitro bioactivity test and in vivo toxicity test. Results showed that the production of the composites was successfully achieved, yielding materials with particles well dispersed within the matrices. Evaluation of the in vivo inflammatory response showed low activity levels for all composites although composites with silane treated BCP particles led to milder inflammatory responses than composites with non-treated particles

Preparation and biocompatibility of poly (methyl methacrylate) reinforced with bioactive particles

Calcium phosphates and bioactive glasses have been used in many biomedical applications for more than 30 years due basically to their bioactive behavior. However, ceramics are too brittle for applications that require high levels of toughness and easy processability. In this work, a biphasic calcium phosphate (BCP) and a bioactive glass composition (BG) were combined with polymers to produce composites with tailorable properties and processability. The BCP particles were synthesized by a precipitation technique. The BG particles were produced by sol-gel processing. The BCP particles were treated with a silane agent to improve the compatibility between particles and the polymer matrix. Dense samples were produced by hot pressing (200 °C) a mixture of 30 wt.% of particles in poly (methyl methacrylate). The samples produced were characterized by X-ray diffraction, infrared spectroscopy and scanning electron microscopy. Mechanical properties were evaluated by a three point bending test. Samples were also submitted to in vitro bioactivity test and in vivo toxicity test. Results showed that the production of the composites was successfully achieved, yielding materials with particles well dispersed within the matrices. Evaluation of the in vivo inflammatory response showed low activity levels for all composites although composites with silane treated BCP particles led to milder inflammatory responses than composites with non-treated particles

Estudo imunológico da esquistossomose mansoni intestinal antes e após tratamento com aminonitrotiazol

Foram dosadas as imunoglobulinas e realizados testes cutâneos para se avaliar o sistema imunológico de pacientes portadores da forma intestinal da esquistossomose mansoni. Estes testes foram realizados antes do tratamento com aminonitrotiazol e após trinta, sessenta e noventa dias do tratamento. Antes do tratamento o nível de IgG (1893 ± 472 mg%) apresentava-se elevado, mas os níveis de IgA (186 ± 74 mg%) e de IgM (91 ± 26 mg%) achavam-se normais. Decorridos trinta, sessenta e noventa dias do tratamento, o nível de IgG diminuiu, observando-se ligeira elevação de IgA bem como de IgM. Os pacientes, antes do tratamento, quando testados com schistosomina e anti IgE apresentaram áreas de 1,22 ± 0,36 cm² e 1,04 ± 0,25 cm², respectivamente. Noventa dias após o tratamento, as reações à schistosomina e ao soro anti IgE produziram reações com áreas ainda maiores. Os testes de hipersensibilidade retardada mostraram que 35% dos pacientes reagiram à schistosomina e 71% ao 2-4 dinitrofluorobenzeno

In vitro bioactivity and cytotoxicity of chemically treated glass fibers

Samples of a commercial glass fiber FM® (Fiber Max) were used to test the efficacy of a chemical sol-gel surface treatment to enhance their bioactivity. After treatment with tetraethoxysilane (TEOS), individual fiber samples were soaked into a simulated body fluid (SBF) solution, from which they were removed at intervals of 5 and 10 days. Micrographs obtained by scanning electron microscopy (SEM) analysis of samples chemically treated with TEOS revealed the formation of a hydroxyapatite (HA) coating layer after 5 days into SBF solution. Fourier transform infrared spectroscopic (FTIR) analyses confirmed that the coating layer has P-O vibration bands characteristic of HA. The in vitro cytotoxicity was evaluated using a direct contact test, minimum essential medium elution test (ISO 10993-5) and MTT assay. Fibers immersed in SBF and their extracts exhibited lower cytotoxicity than the controls not subjected to immersion, suggesting that SBF treatment improves the biocompatibility of the fiber