A comparison of different cytological stains for biological dosimetry.
OBJECTIVE
This paper examines the relative accuracy of analysis of unstable chromosomal aberrations (dicentrics, rings and fragments) in lymphocyte metaphases using four microscope slide staining options, widely used to assess radiation overdose or to survey occupationally exposed subjects.


METHODS
Peripheral blood lymphocytes from a healthy donor were irradiated with 1.5 and 3.0 Gy of X-rays at a dose rate of 0.715 Gy/min. Dicentrics were scored by different cytological stains in order to compare block staining: Giemsa and 4', 6-Diamidine-2'-phenylindole dihydrochloride (DAPI); with techniques that highlight centromeres: C-banding and Centromere Multiplex Fluorescence in situ Hybridization (CM-FISH).


RESULTS
At each of the two doses, the values for dicentrics per cell observed with each staining method were compared. In terms of dose estimation, no statistical difference was observed between the evaluated methods (chi(2) p: 0.27 and 0.64, respectively; analysis of variance - ANOVA, p > 0.99). Therefore, the evidence of centromeres by C-banding and CM-FISH did not promote an increased discovery of dicentrics. On the other hand, when confirmation of unequivocal identification of dicentrics is needed, C-banding and CM-FISH can be a suitable method to confirm its presence. Economical and social factors must be taken into account in the decision of method as well.


CONCLUSIONS
For routine use where several hundreds of cells need to be reliably processed and analyzed daily, processing slides by block staining with Giemsa and DAPI is preferable. However, to assist in resolving the minority of images that are ambiguous, C-banding and CM-FISH provide a better identification of suspected dicentrics.
Fernandes
Thiago Salazar
TS
Grupo de Estudos em Radioprotecao e Radioecologia (GERAR), Universidade Federal de Pernambuco, Centro de Tecnologia e Geociencias/Departamento de Energia Nuclear, Cidade Universitaria, Pernambuco, Brazil. thiagosalazar@hotmail.com
Lloyd
David
D
Amaral
Ademir
A
D001399:Azure Stains; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007211:Indoles; D008214:Lymphocytes / Q000528:radiation effects / Q000648:ultrastructure; D008297:Male; D011874:Radiometry
D001399:Azure Stains; D007211:Indoles; C007293:DAPI