RESUMO
Human adipose stem cells (ASCs) hold great potential for regenerative medicine approaches, including osteogenic regeneration of bone defects, that fail to heal autonomously. Osteogenic differentiation of stem cells is dependent on the stimulation of biophysical factors. In the present study, the effects of hypergravity, hypoxia, and hyperbaric treatment were investigated on adipose stem cell (ASC) metabolic activity, quantified by PrestoBlue conversion, and cell numbers, evaluated by crystal violet staining. Osteogenic differentiation was assessed by alkaline phosphatase (ALP) activity and cresolphthalein staining of calcium deposition. Differentiation was performed for 12 days, which was accompanied by periodical stimulation. Increasing gravity forces up to 50x g did not affect ASC viability, but it enhanced osteogenic markers with a strongest effect between 20 and 30x g. Hyperbaric stimulation at 3 bar decreased ASC cell numbers but increased ALP activity and calcium deposition. Hypoxia at 8 % atmospheric oxygen did not affect ASC proliferation, while cell numbers were reduced at 3 % oxygen. Furthermore, hypoxic conditions produced opposing results on osteogenic markers, as ALP activity increased whereas cresolphthalein staining decreased upon stimulation. These data demonstrated that intermittent short duration of basal physical or chemical impulses interfere with the osteogenic differentiation of ASCs. Our findings could be of specific relevance in ASC based therapies for regenerative medicine and bone tissue engineering approaches.
Assuntos
Hipergravidade , Células-Tronco Mesenquimais , Tecido Adiposo , Fosfatase Alcalina/metabolismo , Cálcio/metabolismo , Diferenciação Celular , Células Cultivadas , Violeta Genciana/metabolismo , Violeta Genciana/farmacologia , Humanos , Hipóxia/metabolismo , Osteogênese , Oxigênio/metabolismo , Fenolftaleínas , Células-Tronco/metabolismoRESUMO
This report is concerned with an efficient, Cu(I)-mediated method for the radiosynthesis of [(18)F]trifluoromethyl arenes, abundant motifs in small molecule drug candidates and potential radiotracers for positron emission tomography. Three (18)F-labelled radiotracer candidates were synthesised from [(18)F]fluoride ions as proof of principle. The new protocol is widely applicable for the synthesis of novel radiotracers in high radiochemical yields.
Assuntos
Radioisótopos de Flúor/química , Marcação por Isótopo/métodos , Compostos Radiofarmacêuticos/síntese química , Catálise , Cobre/química , Fluoretos/química , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos/farmacologiaRESUMO
Hexafluoroacetone was applied as a bidentate protecting and activating agent for the syntheses of RGD-peptide mimetics starting from iminodiacetic acid in solution and on solid phase.