Simple and precise method for counting ciliary beats directly from the TV monitor screen.

The modern optical microscopic technique together with the use of the small perfusion chamber allows the maintenance and observation of isolated ciliated epithelia for many hours in vitro. Counting ciliary beats is a good means for evaluating the behavior of these cells immediately under different environmental conditions and also for evaluating the pharmacologic or toxic action of drugs. Using a TV camera joined to a microscope equipped with the Nomarsky differential interference contrast set, it is possible to see on a TV monitor an image of the cilia at a very high magnification (over 1000 X), with a good resolution. This paper describes a method and an instrument, with a digital readout purposely designed to receive and count signals from a phototransistor placed directly on the protective screen of the TV monitor to correspond exactly with the point of passage of the coming and going movement of the selected cilia. In this way, it is possible to obtain (in real time and in a simple way through visual observation of the beat) the final count, which consists of the number of passages, in a prefixed time, in front of the phototransistors of the dark area which represents the ciliary body on the light background.