title: Cytogenetic alterations and oxidative stress in thyroid cancer patients after iodine-131 therapy.
abstract: This study aimed to assess two end-points of DNA damage, namely chromosomal aberrations and micronuclei in peripheral lymphocytes, and their possible relationship with oxidative stress (which may be related to DNA damage and repair) in thyroid cancer patients receiving therapeutic doses of (131)I. Nineteen patients receiving 2590 MBq (70 mCi) were studied. Chromosomal aberrations were scored using standard cytogenetic methods and micronuclei scored in cytokinesis-blocked lymphocytes. Oxidative stress was assessed by determining thiobarbituric acid-reactive substances in blood, total plasma antioxidant status and serum uric acid levels. All parameters were assessed before treatment and 1 and 6 months after (131)I administration. The frequency of micronucleated cells per 1000 binucleated cells scored (mean +/- SEM) increased significantly from 5.21 +/- 0.80 to 9.68 +/- 1.22 1 month after treatment (P < 0.01) and to 8.42 +/- 1.28 6 months after treatment (P < 0.05). The frequency of cells with chromosomal aberrations, excluding gaps, per 100 cells, increased significantly from 1.68 +/- 0.41 to 3.47 +/- 0. 55 1 month after treatment (P < 0.01) and to 4.05 +/- 0.46 6 months after treatment (P < 0.01). Oxidative stress parameters showed slight modifications over the time period studied, but the differences were not significant except for a decrease in thiobarbituric acid-reactive products 6 months after therapy (P < 0. 05) and in serum uric acid concentration 1 and 6 months after therapy (P < 0.01). This report demonstrates slight but significant and persistent DNA damage in (131)I-treated patients as assessed by cytogenetic assays. There was no clear correlation between the cytogenetic findings and oxidative stress parameters studied.
authors.affiliation: Department of Genetics, Faculty of Medical Sciences, New University of Lisbon, R. da Junqueira 96, P 1349-008 Lisbon, Portugal.
authors.forename: O
authors.initials: O
authors.lastname: Monteiro Gil
authors.forename: N G
authors.initials: NG
authors.lastname: Oliveira
authors.forename: A S
authors.initials: AS
authors.lastname: Rodrigues
authors.forename: A
authors.initials: A
authors.lastname: Laires
authors.forename: T C
authors.initials: TC
authors.lastname: Ferreira
authors.forename: E
authors.initials: E
authors.lastname: Limbert
authors.forename: A
authors.initials: A
authors.lastname: Léonard
authors.forename: G
authors.initials: G
authors.lastname: Gerber
authors.forename: J
authors.initials: J
authors.lastname: Rueff
mesh_terms: D000328:Adult; D000368:Aged; D002869:Chromosome Aberrations; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use; D008214:Lymphocytes / Q000473:pathology / Q000648:ultrastructure; D008297:Male; D048629:Micronuclei, Chromosome-Defective / Q000648:ultrastructure; D008875:Middle Aged; D018384:Oxidative Stress; D017392:Thiobarbituric Acid Reactive Substances; D013964:Thyroid Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D014527:Uric Acid / Q000378:metabolism
chemical_list: D007457:Iodine Radioisotopes; D017392:Thiobarbituric Acid Reactive Substances; D014527:Uric Acid