2 research outputs found
Preliminary evaluation of DNA damage related with the smoking habit measured by the comet assay in whole blood cells
Artículo de publicación ISIThe alkaline single-cell gel electrophoresis (SCGE)
assay, also called the comet assay, is a rapid and
simple method for the detection of DNA damage in
individual cells. The objective of this study was to
establish if the alkaline SCGE assay in whole blood
cells gives similar results as the same method in
isolated lymphocytes, because whole blood cells are
simpler and more economical to use, specifically in
human genotoxic biomonitoring. To validate the
method, we first used mouse blood cells, because
mouse is one of the most commonly used animals in
genetic toxicology testing. Groups of seven CF1 male
mice were given i.p. injections of relatively low doses
of methyl methanesulfonate (25 mg/kg body weight), a
direct acting genotoxic agent, or cyclophosphamide
(50 mg/kg body weight), which requires metabolic
activation. Three, 6, 8, 12, 16, 20, and 65 hours after
treatment, 5 ML of blood were collected from each
animal and were processed for the alkaline SCGE
assay. On the basis of an analysis of tail moment, the
results showed that this assay can detect DNA damage
induced by both kinds of alkylating mutagens. We
then did a preliminary study to assess the status of
DNA damage in a young (19 to 23 years old) healthy
population of male smokers (n = 6) and nonsmokers
(n = 6) using the comet assay in whole blood cells.
A significant difference was observed between the
two groups, showing that the method is able to detect
DNA damage in the smoking group despite
the short time that the volunteers had actually been
smoking
Prevalence of TPMT and ITPA gene polymorphisms and effect on mercaptopurine dosage in Chilean children with acute lymphoblastic leukemia
Artículo de publicación ISIBackground: Mercaptopurine (6-MP) plays a pivotal role in treatment of childhood acute lymphoblastic leukemia
(ALL); however, interindividual variability in toxicity of this drug due to genetic polymorphism in 6-MP metabolizing
enzymes has been described. We determined the prevalence of the major genetic polymorphisms in 6-MP
metabolizing enzymes in Chilean children with ALL.
Methods: 103 Chilean pediatric patients with a confirmed diagnosis of ALL were enrolled. DNA was isolated from
whole blood and genetic polymorphism in thiopurine S-methyltransferase (TPMT) and inosine triphosphate
pyrophosphatase (ITPA) coding genes were detected by polymorphism chain reaction-restriction fragment length
(PCR-RFLP) assay.
Results: The total frequency of variant TPMT alleles was 8%. TPMT*2, TPMT*3A and TPMT*3B alleles were found in
0%, 7%, and 1% of patients, respectively. For ITPA, the frequency of P32T allele was 3%. We did not observe any
homozygous variant for TPMT and ITPA alleles. We also analyzed a subgroup of 40 patients who completed the
maintenance phase of ALL treatment, and we found that patients carrying a TPMT gene variant allele required a
significantly lower median cumulative dosage and median daily dosage of 6-MP than patients carrying wild type
alleles.
Conclusion: TMPT genotyping appears an important tool to further optimize 6-MP treatment design in Chilean
patients with ALL.This work was supported by grants from Fundación Nuestros Hijos (JM and
MJF) and FONDECYT 1120809 (MJF). We are indebted to and pleased to
acknowledge Drs. Mary V. Relling and Cristine Crews for TPMT activity
measurement