Microglia
Research has discovered dystrophic (defective development) human microglia. "These cells are characterized by abnormalities in their cytoplasmic structure, such as deramified, atrophic, fragmented or unusually tortuous processes, frequently bearing spheroidal or bulbous swellings." The incidence of dystrophic microglia increases with aging. Microglial degeneration and death have been reported in research on Prion disease, Schizophrenia and Alzheimer's disease, indicating that microglial deterioration might be involved in neurodegenerative diseases. A complication of this theory is the fact that it is difficult to distinguish between "activated" and "dystrophic" microglia in the human brain.
Micronucleus test
Micronuclei were first used to quantify chromosomal damage by H.J. Evans et al., in root tips of the Broad Bean, "Vicia faba". Subsequently the "in vivo" assay was developed independently by W. Schmid and by J.A. Heddle and their colleagues. The mouse peripheral blood assay was developed by J.T. MacGregor and has now been adapted for measurement by flow cytometry by A. Tometsko and colleagues. The first use of micronuclei in cultured cells was by J.A. Heddle and colleagues in human lymphocytes. The assay has been improved by M. Fenech and colleagues for use in lymphocytes and other cells in culture cells.