ABSTRACT
In some areas of Ramsar, a city in northern Iran, residents receive a much higher annual radiation exposure than is permitted for radiation workers. Induction of adaptive response in residents of Ramsar has been reported previously. In this study induction of such a response in short term exposure to high background levels of gamma radiation is investigated. Fifty male NMRI mice were randomly divided into four groups of 10-17 animals and 53 Wistar rats were randomly divided into five groups of 10-12 animals were studied. Animals in the 1[st] group were kept for 7 days in an outdoor area with normal background radiation while the 2[nd], 3[rd], 4[th] and 5[th] [in case of rats] groups were kept in 3 different outdoor areas with naturally elevated levels of gamma radiation. Animals were then exposed to a lethal dose of 8 Gy gamma radiation. For mice, 30 days after exposure to lethal dose, the survival fraction for the control group was 40% while the 2[nd], 3[rd], and 4[th] groups had survival rates of 20%, 33.30%, and 35.20%, respectively. For rats, 30 days after exposure to the lethal dose, the survival fraction for the control group was 40% while the 2[nd], 3[rd], 4[th] and 5[th] groups had survival rates of 20%, 41.6%, 60.0% and 35.7%, respectively. Results indicate that short term exposure to extremely high levels of natural gamma radiation [up to 196 times higher than the normal background] do not lead to induction of survival adaptive response
ABSTRACT
Over the past decade the US army has widely studied new technologies for stopping sever hemorrhages and has introduced an effective Zeolite based hemostatic agent. On the other hand, Mortazavi and his colleagues previously reported the bio-stimulatory effects of the topical application of radioactive lantern mantle powder on wound healing. Their subsequent studies showed significant changes in some histological parameters concerning healing. In this light, here the bio-stimulatory effect of burned radioactive lantern mantles powder as well as two minerals; bentonite and zeolite arepresented. This experimental study was conducted in the center for radiological studies, Shiraz university of Medical Sciences in 2008. Fifty male Wistar rats were divided randomly into 5 groups of 10 animals each. Following anesthesia, animals' tails were cut at a thickness of 5 mm by using a surgical scissor. No intervention was made on the animals of the 1[st] group. The 2[nd] group to 4[th] group received topical non-radioactive lantern mantle powder, radioactive lantern mantle powder, Bentonite mineral or a mixture of Bentonite-Zeoliteat minerals respectively. After treatment with above mentioned agents, the volume of blood loss was measured using a scaled test-tube. The bleeding time and clotting time were also measured using a chronometer. SPSS software was used for statistical analysis. ANOVA was used for comparing the means of each parameter in the 5 groups. The volume of blood loss, bleeding and clotting times in control animals were 4.39 +/- 1.92 cc, 112.10 +/- 39.60 sec and 94.9 +/- 54.26 sec, respectively. In the 5[th] group in which the animals were treated with a mixture of Bentonite-Zeoliteat minerals, the volume of blood loss, bleeding and clotting times were 1.31 +/- 0.60 cc, 34.50 +/- 4.65 sec and 24.2 +/- 4.61 sec, respectively. This is the 1[st] investigation that studied the alterations of bleeding and clotting times following the use of lantern mantle powder as well as bentonite or the mixture of bentonite-zeolite minerals. The results obtained in this study clearly show the significant effect of the volume of blood loss as well as the bleeding time following the topical use of the mixture of bentonite-zeolite minerals. The radioactive and non-radioactive lantern mantle and the bentonite mineral alone had considerable effects but overally the magnitude of the effect was less than that of the mixture of bentonite-zeolite minerals