Micronucleus yield and colorimetric test as indicators of damage in patients' lymphocytes after 131I therapy.
To estimate the absorbed dose received by patients who underwent 131I therapy, a modified compartmental model of the International Commission on Radiological Protection (ICRP) was used. The activity in plasma and micronucleus (MN) frequency (MN test) were measured before and after therapy. To evaluate whether a correlation exists between lymphocytes and absorbed dose, a colorimetric test, based on the tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT test), was used.


METHODS
Twenty patients who underwent 131I therapy were studied. Activity was measured in plasma, and isolated lymphocytes were collected to perform the MN and MTT tests.


RESULTS
The mean MN frequency observed in unexposed patient lymphocytes was comparable with that of healthy subjects. 131I therapy induces a small increase in MN, and a good correlation with the bone marrow absorbed dose was obtained (P = 0.040). A consistent decrease in phytostimulation observed after therapy (MTT test) correlated significantly with bone marrow absorbed dose (P = 0.0085).


CONCLUSIONS
The MTT test appears to be more reliable than the MN test for evaluating lymphocyte damage induced by 131I therapy.
Catena
C
C
Ambiente-Protezione-Tossicologia, Ente per le Nuove Tecnologie, l'Energia e l'Ambiente Centro Ricerche Casaccia, Rome.
Conti
D
D
Trenta
G
G
Righi
E
E
Breuer
F
F
Melacrinis
F F
FF
Montesano
T
T
Ventroni
G
G
Ronga
G
G
D001853:Bone Marrow / Q000528:radiation effects; D003124:Colorimetry / Q000379:methods; D006044:Goiter, Nodular / Q000532:radiotherapy*; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000493:pharmacokinetics; D008213:Lymphocyte Activation / Q000528:radiation effects*; D008214:Lymphocytes / Q000528:radiation effects*; D015162:Micronucleus Tests; D011879:Radiotherapy Dosage; D012016:Reference Values; D012044:Regression Analysis; D015203:Reproducibility of Results; D013964:Thyroid Neoplasms / Q000532:radiotherapy*
D007457:Iodine Radioisotopes