SummaryA comparative study of mammalian (human, rat, rabbit, guinea-pig, horse, dog) platelet aggregation was done using phase contrast microscopy and photometric method and gave us the following results :1. The animal platelets do not spread spontaneously onto glass in contrast to human ones (in their own plasma).2. They do not aggregate in presence of adrenalin, noradrenalin, 5-HT but these amines increase the sensitivity of the platelets towards ADP.3. Although all the platelets aggregate in presence of ADP, bovine thrombin, collagen or thimerosal, there exists some quantitative differences from one species to another.4. Adenosine and AMP are inhibitors of ADP-induced aggregation for human, rabbit and dog platelets and not for guinea-pig and horse. As for the rat, if adenosine is not inhibitor, AMP can be inhibitor if used at strong doses.5. There exist great differences in the ability of the various platelet-poor plasmas studied to inactivate the aggregating property of ADP, as for instance the weakest being the human one and the strongest the rat one.6. The authors insist on the importance of ADP-inhibition by AMP and adenosine, and the ADP-inactivation by the plasmas for the mammalian platelet aggregation and almost disaggregation.
Estimation of age based on tooth cementum annulations: A comparative study using light, polarized, and phase contrast microscopy