RESUMO
BACKGROUND: The biological effects of cigarette smoke are not fully known. To improve our understanding of the action of various chemical agents, we investigated the biodistribution of sodium pertechnetate (Na99mTcO4) in mice exposed to cigarette smoke. METHODS: Fifteen BALB/c male mice were exposed to the smoke of nine whole commercial cigarettes per day, 3 times/day, for up to 10 days to whole body exposure in a chamber. A control group of 5 BALB/c male mice was sham-smoked. One day later, the exposed and control groups of mice received (7.4 MBq/0.3 ml) of Na99mTcO4 before being killed at 30 min. Bones, brain, heart, intestine, kidney, liver, lungs, muscle, pancreas, spleen, stomach, testis and thyroid were weighed and these organs and blood radioactivity recorded with a gamma counter. The percentage per gram of tissue of injected dose (%ID/g) was determined for each organ. RESULTS: Cigarette smoke significantly decreased (p < 0.05) the %ID/g in red blood cells, bone, kidney, lung, spleen, stomach, testis and thyroid of the exposed mice. CONCLUSION: The toxic effects of cigarette smoke reduced the Na99mTcO4 biodistribution.
RESUMO
We have reported that drugs alter the biodistribution of radiopharmaceuticals used in diagnostic imaging in nuclear medicine. Knowledge of such altered biodistribution is important in making diagnostic from scintigraphy. Mitomycin-C is used as component of many chemotherapeutic regimens to treat different tumors. The biological activities of mitomycin-C can be explained by its ability to inhibit deoxyribonucleic acid synthesis. Since patients on chemotherapeutic treatment can be submitted to nuclear medicine procedures, we studied the mitomycin-C effect on the bioavailability of the technetium-99m-labelled sodium pyrophosphate (9mTc-PYP) using an animal model. Mitomycin (0.45 mg) was administered by ocular plexus way Balb/c mice. One hour after the last dose, 99mTc-PYP (7.4 MBq) was administered and after 0.5 hr the animals (n = 15) were rapidly sacrificed. The organs were isolated, the radioactivity counted in a well counter and the percentage of radioactivity (%ATI) calculated. The results have shown that in the treated animals the %ATI has been decreased in spleen, thymus, heart and brain and increased in lung, liver and bone. The effect of this chemotherapeutic drug on the 99mTc-PYP biodistribution was statistically significant (Wilcoxon test, p < 0.05) and it could be explained by the metabolization or therapeutic action of mitomycin-C.
