title: Low dosage of 131iodine effects on chromosomes.
abstract: The aim of this study was to evaluate the effect on human lymphocyte chromosomes of the (131)I dosage used in scintigraphy on thyroid patients. Until now, there has been as absence of conclusive reports on the effects produced by such dosage. Samples were obtained from 21 patients, and the blood was collected in two occasions: Twenty-four hours prior (control) and after administration of the radionuclide (test). Cells were placed in 1640 RPMI medium with bovine calf serum and incubated with phytohaemagglutinin for 48 and 72 hr at 37 degrees C. Chromosomes were stained with Giemsa Gurr (2 percent, pH = 6.8), and analyzed by two independent investigators by optical microscopy. Of the 6,300 metaphases analyzed from the 48- and 72-hr cultures, 1,146 and 216 gaps and 682 and 52 breaks were found in the test group, respectively. Of the 6,300 metaphases analyzed from the control group, 291 gaps and 119 breaks were observed in the 48-hr cultures whereas in the 72-hr cultures, 10 gaps, and no breaks were found. Our results show that (131)I is responsible for the observed chromosome alterations (paired t-test, p <.05). We suggest re-evaluating the use of (131)I and replacing it with the (123)I, mainly on those patients at fertile age.
authors.affiliation: Hospital Universitário Clementino Fraga Filho, UFRJ, Departamento de Radiologia, CEP: 21941-590, Rio de Janeiro, RJ, Brazil.
authors.forename: Claudia
authors.initials: C
authors.lastname: Lopes Rodrigues
authors.forename: Rossana
authors.initials: R
authors.lastname: Corbo
authors.forename: Flávia Paiva
authors.initials: FP
authors.lastname: Proença Martins
authors.forename: Léa Mirian
authors.initials: LM
authors.lastname: Barbosa da Fonseca
authors.forename: Ivar Pinheiro
authors.initials: IP
authors.lastname: Aranha
authors.forename: Bianca
authors.initials: B
authors.lastname: Gutfilen
mesh_terms: D000328:Adult; D000368:Aged; D019457:Chromosome Breakage; D002872:Chromosome Deletion; D002877:Chromosomes, Human / Q000187:drug effects*; D006801:Humans; D007457:Iodine Radioisotopes / Q000494:pharmacology*; D008214:Lymphocytes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D008677:Metaphase / Q000235:genetics; D008875:Middle Aged; D011877:Radionuclide Imaging / Q000009:adverse effects; D013959:Thyroid Diseases / Q000000981:diagnostic imaging
chemical_list: D007457:Iodine Radioisotopes