title: Evaluation of the reticulocyte micronucleus assay in patients treated with radioiodine for thyroid cancer.
abstract: In the case of accidental radiation exposure, biological dosimetry has an important role. Previous studies have indicated that the flow cytometric micronucleus (MN) assay in human transferrin receptor positive reticulocytes (Tf-Ret) in blood could be a sensitive biomarker for chromosome damage. In the present investigation, the utility and sensitivity of this method was studied in 44 young patients from Belarus, who were treated with 131I for thyroid cancer. Red marrow (RM) is the critical organ in radioiodine therapy (RIT). In our patients, it was exposed to 100-700 mSv low-dose rate irradiation within 2-4 days. About 3 days after 131I administration, the frequency of micronucleated-Tf-Ret (f(MN-Tf-Ret)) increases within 1 day to a maximum and declines in the following 2-5 days to its value before treatment. A total dose of 100 mSv was easily detectable. The sensitivity of the assay after acute irradiation may be 50 mSv. The method should be useful for monitoring individuals after a radiation accident, provided blood samples can be obtained within a few days after exposure. The time-course of f(MN-Tf-Ret) is interpreted using a model, which considers the exponential exposure of red marrow in RIT as well as the kinetics of erythroblast maturation and reticulocyte migration into the peripheral circulation. Similar modelling was done on published data of MN in immature mouse erythrocytes. Striking similarities in the kinetic and in the yield of MN-induction were found between these two species. This lends support for the use of the mouse as a model for the MN-induction in humans.
authors.affiliation: Rudbeck Laboratory, University of Uppsala, Dag Hammarskjölds väg 20, 75185 Uppsala, Sweden. jan.grawe@rudbeck.uu.se
authors.forename: Jan
authors.initials: J
authors.lastname: Grawé
authors.forename: Johannes
authors.initials: J
authors.lastname: Biko
authors.forename: Reinhard
authors.initials: R
authors.lastname: Lorenz
authors.forename: Christoph
authors.initials: C
authors.lastname: Reiners
authors.forename: Helga
authors.initials: H
authors.lastname: Stopper
authors.forename: Stanislav
authors.initials: S
authors.lastname: Vershenya
authors.forename: Vladimir
authors.initials: V
authors.lastname: Vukicevic
authors.forename: Klaus
authors.initials: K
authors.lastname: Hempel
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use*; D008297:Male; D015162:Micronucleus Tests; D011874:Radiometry; D011990:Receptors, Transferrin / Q000235:genetics*; D012156:Reticulocytes; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000532:radiotherapy*
chemical_list: D015415:Biomarkers; D007457:Iodine Radioisotopes; D011990:Receptors, Transferrin