[ effects of low doses of diagnostic x-rays on cellular and humoral immunological responses in balb/c mice]

The immunosuppressive effects of high doses of ionizing radiation have long been known. Recently, in human and experimental animal models it has been reported that low dose radiation may have immunostimulatory effects. The aim of this study was to evaluate the effects of low doses of diagnostic X-ray on cell mediated and humoral immune responses in a Balb/c animal model. In this experimental study, three groups of male Balb/c mice were exposed once, twice and three times to 30 mGy X-ray radiation. Two to 4hrs after the irradiation, the delayed type hypersensitivity [DTH] and humoral responses to sheep red blood cell [SRBC] were measured and compared to the responses of sham and control groups. The mean titer of anti-SRBC antibodies in two-times irradiated [74.66 +/- 26.12] and three-times irradiated [128 +/- 70.1] groups were significantly higher than those of the control [26.66 +/- 8.26] and sham [28.8 +/- 20.86] groups [p<0.001]. However, no significant differences were observed between the mean titer of anti-SRBC antibodies in one-time irradiated [22.4 +/- 8.76] and either control or sham groups. Similarly, comparing DTH responses showed that the differences between either two-times irradiated [12.2 +/- 3.9] or three times-irradiated [6.9 +/- 3.7] and control [4 +/- 0.2] or sham [4.3 +/- 3] groups was statistically significant [p<0.001]. Theses results showed that twice and three-times irradiated mice demonstrated significant stimulatory effects on both DTH and antibody responses. However, one-time irradiated animals did not exhibit any bio-positive effect on DTH and humoral responses. Moreover, no statistically significant difference was observed between the DTH and antibody responses of two-times and three-times irradiated mice

[ bio-positive effects of burned radioactive lantern mantle powder on the wound healing in rat]

Poor educated people in some parts of Iran use burned mantles as a wound healing powder to prevent the bleeding and infections caused by injuries. Some lantern mantles contain low levels of radioactive thorium for maximizing the light output, while non-radioactive mantles contain yttrium. Although radioactive lantern mantles may cause a minimal radiation health hazard, it is generally believed that it would be dangerous when inhaled or ingested. This study was conducted to evaluate the effect of burned radioactive lantern mantles on wound healing. Twenty rats were divided randomly into two groups of 10 animals each. After inducing general anesthesia, full thickness excision wound [314 +/- 31.4 mm[2]] was made on the dorsal neck in all animals. The 1st group received topical burned radioactive lantern mantle powder at 1st-3rd day after wound excision. The presence of radioactivity in the mantle was detected using a Monitor-4 survey meter. The 2nd group received non-radioactive lantern mantle powder at the same days. Accurate blind surface measurement of the wounds was performed by transparency tracing to assess the wound healing at 1st, 3rd, 7th, 10th and 15th days after excision. A progressive reduction in the wound area of both groups was observed. However, for thorium treated group, the rate of recovery was significantly enhanced compared to that of the control group. Although this value in the thorium group was not significantly different from that of the control group at the 3rd and 5th days after wounding, a statistically significant difference was observed between these two groups at the day7, day10 and day 15. The mean wound surface in thorium and control groups were 150.20 +/- 15.87 and 186.37 +/- 12.68 mm[2] at day7 [p<0.001], 92.90 +/- 15.97 and 134.12 +/- 14.19 mm[2] at day 10 [p<0.001], 1.40 +/- 0.41 and 8.56 +/- 2.04 mm[2] at day15 after wounding, respectively [p<0.01]. These findings suggest that low-level radioactive burned mantle accelerates wound healing in rats. However, as thorium oxide is a known human carcinogen, more research is needed to clarify if low levels of radioactive burned mantle can be utilized for enhancing wound healing