PRIMARY CILIA IN NORMAL AND PATHOLOGICAL TISSUES

The medical literature in pathology contains a surprising number of an ecdotal reports of primary cilia, with authors often expressing some i ncredulity at finding such organelles, In this update of an earlier re view, I will argue that primary cilia should by now be regarded as reg ular cell organelles, not some form of atypical response to unusual ci rcumstances. In all situations in which their presence is essential, t hey unquestionably act as sensory transducers, Detection by electron m icroscopy has been the most reliable means until recently, but is time -consuming and slow for any systematic investigation or experimental a pproach, Immunostaining with an antibody directed against detyrosinate d tubulin is rapidly changing the situation, and we can now detect the ir presence, frequency, disposition and overall characteristics relati vely quickly, allowing better statistical analysis and correlations in abnormal physiological and pathological conditions, To be useful and meaningful, comparative studies need a reliable database of informatio n about primary cilia under 'normal' circumstances, It is hoped that s uch work will in itself give much further insight into the general sig nificance of these organelles, especially combined with the more exper imental approaches that can now be adopted in the study of their devel opment and function, which looks increasingly promising with the new t echnological improvements.