A new staining technique of 'thick smears' was developed tor diagnosis of malaria using transmission fluorescence microscopy. Plasmodium falciparum cultured in vitro was used as a model. The infected blood was mixed 1 : 1 -1 :2 with acridine orange (AO) solution (final concentrations of 50-lOOu.g/ml in 0.01 M Tris-HCI buffer or in PBS, pH 7.0-7.5). Immediately or several minutes later, haemolyzed or non-haemolyzed 'thick smears' were observed directly by fluorescence microscopy using an interference filter specially designed for excitation of AO or commercially available, three (interference-, glass- and triacetyl cellulose film-) types of B-excitation filters with halogen- or daylight-illuminated microscopes. All of these filters were capable of detecting... |