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Advisor(s)
Abstract(s)
Epidemiological studies commonly associate the incidence of cancers with the exposure to
genotoxicants. This exposure may be analyzed using effect biomarkers allowing an early
detection of health alterations. Micronucleus assay constitutes a useful tool to detect
chromosomal damage, genomic instability and carcinogenic events. Cancers are usually
from epithelial origin, and therefore micronucleus test (MN) in urine derived cells (UDC)
assumes a great role on toxicological studies.
Sampling of UDC is an easy and minimally invasive procedure, representing an advantage
in human biomonitoring studies. The main concern related with UDC is the lack of
standardization of MN protocol. Data show a large variability of the method, in particular
what concerns to staining procedure, which may lead to bias. The use of different
methodologies regarding MN in UDC may contribute to the large inter-laboratory variations
and consequently for inconsistencies among studies.
Aim: i) Select the most reliable method to stain UDC of those most commonly used - Giemsa and Feulgen. Giemsa - staining permits a quick preparation of slides for microscopic evaluation, however it is a non-DNA-specific stain which may favor false positive readings through the presence of other cellular structures (nonnuclear bodies, bacteria or keratohyalin granules). Feulgen - staining, although more time consuming, is a DNA specific stain which allows a good contrast between DNA material and cytoplasm; ii) Establish a detailed set of criteria for scoring all of the biomarkers in UDC; iii) Standardize the application of the mn assay in UDC.
Description
Keywords
Cancer Exposure to Genotoxicants Biomarkers Urine Derived Cells (UDC) Genotoxicidade Ambiental Toxicologia
