Evaluation of technetium-99m decay on Escherichia coli inactivation: effects of physical or chemical agents.
Technetium-99m (99mTc) has been used in nuclear medicine and in biomedical research to label molecular and cellular structures employed as radiotracers. Here, we have evaluated, on a DNA repair proficient Escherichia coli strain, the 99mTc decay inactivation and the influence of the (i) pre-treatment with metal ion chelators or of the (ii) treatment with a free radical scavenger on the protection of the cells against the lethal effect of the 99mTc. As SnCl2 is frequently used as a reducing agent in the 99mTc-labeling process, we have also studied the capability of SnCl2 to alter the biological effects induced by the 99mTc decay. As we are exposed to either chemical or physical agents in the nature, we have decided to study a possible influence of the ultraviolet solar radiation in the biological phenomena induced by the 99mTc decay. Our data point out (i) a very important role of the Auger and/or conversion electrons in the cytotoxicity induced by the 99mTc decay; (ii) SnCl2, the metal ion chelators and the free radical scavenger protect the cells against the lethal effect of the 99mTc; and (iii) near-UV does not alter the lethal effect of the 99mTc decay.
Departamento de Biofísica e Biometria, Universidade do Estado do Rio de Janeiro, Brazil.
C R
CR
Silva
J O
JO
Valsa
M S
MS
Caniné
A
A
Caldeira-de-Araújo
M
M
Bernardo-Filho
D015082:2,2'-Dipyridyl / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology*; D004492:Edetic Acid / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects* / Q000528:radiation effects*; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006207:Half-Life; D020160:Sodium Benzoate / Q000494:pharmacology; D013667:Technetium / Q000633:toxicity*; D013890:Thiourea / Q000494:pharmacology; D017971:Tin Compounds / Q000494:pharmacology; D014466:Ultraviolet Rays
D002614:Chelating Agents; D016166:Free Radical Scavengers; D017971:Tin Compounds; C023599:stannous chloride; D015082:2,2'-Dipyridyl; D013667:Technetium; D004492:Edetic Acid; D013890:Thiourea; D020160:Sodium Benzoate