Study on platelet shape and its relation to function

In a study on platelet shape and its relation to function, we modified the light microscopy method by Zucker and Borrelli in 1954. The platelets nearly in vivo condition were fixed in 1% glutaraldehyde (pH 7.4, 355mOs) containing sodium citrate. After confirming their en face and profile contour under a light microscope, they were classified into disc, hemisphere, sphere and other form (including bipolar form) according to our criteria and were judged whether they had pseudopods.The experiment on the effect of various conditions in the exsanguination and the procedures on the platelet morphology showed that it was readily affected. From the standpoint that the native platelets are almost discs without or rarely with pseudopods, a thicker needle (18G, 1.20mm in the inner diameter) was better than a thinner needle (23G, 0.60mm in inner diameter) and in the case of 18G needle the platelet morphology was not affected up to 10ml. of blood drawn. Citrate or heparin did not significantly alter the morphology but EDTA did prominently. The character of the surface of the glass tubes, siliconized or not, did not produce any significant difference.Fourty normal individuals (twenty males and twenty females) with ages between 20-43 were examined for the platelet morphology under a strict condition of exsaguination and procedures in order to minimize the artifacts in the platelet shape. Discs were found in 88.6±4.05(SD)%, hemispheres 6.6±3.65%, spheres 1.3±0.95%, other forms 3.7±1.40% (including the bipolar forms 0.6±0.65%) and the platelets with pseudpods were in 9.6±5.10%. No significant difference was found between males and females. Short discussions were made on the significance of discoid shape and some conditions which affect the shape.