Cytochemical analysis of mast cell granules after poly-dl-lysine action

Several chemical compounds induce amine liberation from mast cells but do not necessarily provoque the granule expulsion. For example, poly-dl-lysine induces modifications of the cellular membrane permeability which promotes ion exchange at the level of mast cell granules. Few of them are expulsed but the majority remains in the cytoplasm and appears less dense to the electrons. A cytochemical analysis has been performed to determine the composition of these granules after the polylysine action.We have previously reported that it was possible to demonstrate polyanions on epon thin sections using a cetylpyridinium ferric thiocyanate method. Organic bases are selectively stained with cobalt thiocyanate and the sulfhydryle groups are characterized with a silver methenamine reaction. These techniques permit to reveal the mast cell granule constituents, i.e. heparin, biogenic amines and basic proteins.

The Influence of Benzamidine Derivatives on Human Platelet Function

SummaryThe influence of derivatives of benzamidine, benzylamine and phenylguanidine on platelet function was investigated in vitro. Among the compounds tested 4-nitro-benzoic acid 4’-amidinoanilide, 4-aminobenzoic acid 4’-amidinoanilide, 4-amidino-benzoic acid anilide and 4-amidinobenzoic acid 3’,4’-dimethoxyanilide were found to be potent inhibitors of platelet aggregation induced by ADP, collagen and thrombin. Other platelet functions, such as the thrombin-induced amine liberation, serotonin and adenosine uptake, retraction and phosphodiesterase activity, were not influenced. The action of the benzamidine derivatives, known to be thrombin inhibitors, is not caused by an inhibition of the clotting enzyme, but it seems to be mainly due to the prevention of the ADP effect on platelets.