RESUMO
Multilamellar liposomes incorporating essential oil of Brazilian cherry (Eugenia uniflora L.) leaves were produced by dry film hydration. Gas chromatography demonstrated the compounds found in the essential oil were effectively incorporated in the aqueous dispersions of liposomes. Differential scanning calorimetry analyses revealed the incorporation of the essential oil did not cause phase separation in the membrane structure; the gel-liquid crystalline transition temperature (main transition) remained the same despite the higher heterogeneity indicated by the transition peak broadening. Different cryoprotectors (sucrose and trehalose) were added to the liposomal formulations to be tested in their ability to protect the liposomal structure during the lyophilization. The morphological aspect of the lyophilized powders analysed by scanning electron microscopy showed significant differences among the samples with and without cryoprotectors. Fourier-transform infrared spectroscopy indicated the cryoprotectors interacted effectively with the polar heads of phospholipids in the bilayer. In terms of water absorption, trehalose was identified as a much more effective protector agent against it than sucrose. The cryoprotectors showed different degrees of effectiveness of preservation of the liposomal structure when the rehydration assays of lyophilized liposomes were carried out, as particle size measurements indicated a moderate process of fusion when the formulations with sucrose were rehydrated.
Assuntos
Lipossomos/química , Óleos Voláteis/administração & dosagem , Óleos Voláteis/química , Syzygium/química , Varredura Diferencial de Calorimetria , Crioprotetores , Composição de Medicamentos , Liofilização , Microscopia Eletrônica de Varredura , Óleos Voláteis/isolamento & purificação , Folhas de Planta/química , Espectroscopia de Infravermelho com Transformada de Fourier , Água/químicaRESUMO
O artigo não apresenta resumo.
RESUMO
The basal and stimulated metabolism of leukocytes obtained from fetally malnourished and normal children was comparatively studied. All basal activities of the leukocytes from malnourished children were significantly lower than those observed in normal children: Glucose-6-P-deydrogenase activity was 1.04 +/- 0.12 against 1.27 +/- 0.22 mumoles/min/10(8) cells; leukocyte-oxidase activity was 0.19 +/- 0.03 against 0.31 +/- 0.05 OD units/15 min/2.5 x 10(6) cells, oxygen uptake was 384 +/- 48 against 728 +/- 103 nmoles 0(2)/hr/10(8) cells. The conversion of glucose -1(14)C to 14CO2 was 83 +/- 10 nmoles/10(8) cells in malnourished children and 134 +/- 22 in controls. The response of all the parameters studied to the stimulation of phagocytosis was also significantly lower in fetally malnourished than in control babies.
