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F Braga

Publications and source records attributed to F Braga.

6 recordsLinked to original sources

Oleanolic acid inhibits the activity of the multidrug resistance protein ABCC1 (MRP1) but not of the ABCB1 (P-glycoprotein): possible use in cancer chemotherapy.

The effects of oleanolic acid (OA) on ABCB1 and ABCC1 activities were studied in a cell line constitutively expressing both proteins. It was observed that OA did not alter ABCB1 activity, but inhibited the activity of ABCC1 protein. This inhibition was reversible and only occurred in the presence of OA. In addition, OA did not alter the expression of ABCC1 mRNA. These results suggest that OA could be a good choice in the treatment of MDR tumours, either as a chemotherapic itself in tumours bearing ABCB1, or as an adjuvant in the chemotherapy of ABCC1 expressing tumours.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Homologous passive cutaneous anaphylaxis (PCA) in mice and heterologous PCA induced in rats with mouse IgE.

A study was made of the effect of anit-histamine, antiserotonin and of different anti-anaphylactic drugs on PCA reactions induced in mice with IgG1 or IgE. Further, using the ability of mouse IgE to sensitize rat mast cells, a comparative study was also made of PCA reactions induced in mice and rats with mouse IgE. Antihistamines produced a partial inhibition of PCA reactions induced in mice with mouse IgG1 or IgE and in rats with mouse IgE whereas antiserotonin inhibited PCA reactions induced in rats with mouse IgE, but had no effect on PCA reactions induced in mice with mouse IgG1 or IgE. The simultaneous use of antihistamine and antiserotonin resulted in a total inhibition of PCA reactions induced in mice with IgG1 and in a marked but not total inhibition of PCA reaction due to IgE; PCA reactions induced in rats with mouse IgE were totally inhibited. Compounds known to change the intracellular level of cyclic AMP were found to have little or no effect on PCA reactions induced in mice with either IgG1 or IgE in spite of producing a complete marked inhibition of PCA reactions induced with mouse IgE in rats. Diethylcarbamazine or disodium cromoglycate were also very effective inhibitors of rat PCA reactions induced with mouse IgE although having no effect on PCA reaction induced in mice with this same antibody or with IgG1. Thus, in spite of sharing common mediators released from the same type of target cell sensitized with the same type of antibody, PCA reactions induced in mice and rats with mouse IgE reacted very differently to the pharmacological effect of most of the drugs tested. This fact seems to indicate that the physiological mechanism operating in mouse mast cells are different from those operating in rat mast cells.

Animals↗