Effect of in vivo exposure to iodine-131 on the frequency and persistence of micronuclei in human lymphocytes
- Univ. of Cincinnati College of Medicine, OH (United States)
The validity of the micronucleus test as a biomarker of chromosome damage in dividing mammalian cells is well established. This assay was used to study the response of peripheral lymphocytes of a 34-yr-old male patient following treatment with [sup 131]I ablative radiation therapy following a total thyroidectomy. Coincidentally, 8 mo before diagnosis, the patient had provided a blood sample for an in vitro study of micronucleus induction following exposure to graded doses of x-rays. The background frequency in the unexposed culture showed a mean count of 6.0 micronuclei per 1000 binucleated (first division) lymphocytes, while mean values of 18.5, 29.0, 41.0, 61.0 and 75.5 micronuclei/1000 cells were observed following x-ray doses of 5, 10, 15, 20, and 25 cGy, respectively. These data fit a nonthreshold, linear dose-response function (y = 2.78x + 3.71; r = .99). Eight months after the in vitro x-ray study, the subject was diagnosed with thyroid cancer. Surgery was performed, and 5 wk later the patient received 1.78 GBq (48 mCi) of [sup 131]I as adjuvant radiation therapy. Blood was drawn 11 d after the radiation treatment and at monthly intervals thereafter to analyze the frequency and persistence of micronuclei. The first posttreatment sample showed 35.5 micronuclei per 1000 binucleate cells. Based on the linear dose-response equation from the earlier study, the sixfold increase in micronucleus frequency suggests a dose to the peripheral blood of approximately 11 cGy. The cytogenetic dose estimate compares to [approximately]30 cGy using a new model based on external whole-body counting data. Data show that radiation-induced cellular lesions persist for months following relatively brief radiation exposure to a medical isotope. Results of this study support the conclusion that the lymphocyte micronucleus test is a rapid, sensitive, and perhaps quantitative biomarker of low-dose (<25 cGy) radiation exposure. 21 refs., 2 figs., 1 tab.
- OSTI ID:
- 7159405
- Journal Information:
- Journal of Toxicology and Environmental Health; (United States), Vol. 40:2-3; ISSN 0098-4108
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
CELL NUCLEI
BIOLOGICAL INDICATORS
IODINE 131
LOW DOSE IRRADIATION
LYMPHOCYTES
BIOLOGICAL RADIATION EFFECTS
THYROIDECTOMY
ANIMAL CELLS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CELL CONSTITUENTS
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
IRRADIATION
ISOTOPES
LEUKOCYTES
MATERIALS
MEDICINE
NUCLEI
ODD-EVEN NUCLEI
RADIATION EFFECTS
RADIOISOTOPES
SOMATIC CELLS
SURGERY
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture
550200 - Biochemistry
550300 - Cytology