Cathodoluminescence studies: from chromatin and chromosome to human hair.

Evidence has been presented to prove that cathodoluminescence (CL) studies of chromosomes and spread, Giemsa stained chromatin may lead to early detection of structural changes, such as the superstructure of heterochromatin. Several compounds including the potent hallucinogenic drugs, LSD and cocaine, have been discovered to be cathodoluminescent. The main issue confronting the CL applications using biological stains is the need for a clear identification of the source (dye or drug) of CL contrast. Unequivocal proof to this matter has been given by studies in which the time-dependent incorporation of LSD into the non-cathodoluminescent, virtually impermeable human hairs have been presented. The major implication of this finding is in forensic applications.