REEVALUATION OF CLASSIC SENILE PLAQUES BY 3-DIMENSIONAL ANALYSIS

We evaluated the proportion of classic plaques among all of the senile plaques in four Alzheimer brains (frontal, temporal, occipital and hi ppocampal areas) by the usual method of two-dimensional analysis using a single methenamine silver-stained section and three-dimensional ana lysis using a set of serial sections. Three-dimensional analysis showe d the number and percentage of classic plaques to be 2-5 times greater than those revealed by two-dimensional analysis. In the hippocampal a rea of one case, no classic plaques were found by two-dimensional anal ysis but three-dimensional analysis showed that some classic plaques w ere present. From these findings, it is suggested that three-dimension al analysis using serial sections is indispensable for subclassifying senile plaques.