Maternal effects and cancer risk in the progeny of mice exposed to X-rays before conception.

To investigate in an animal model whether preconceptual X-ray exposure leads to an altered tumor rate and spectrum in the offspring, a transgeneration carcinogenesis study was carried out. Female mice received X-ray irradiation (2 x 2 Gray) 2 weeks prior to mating with untreated males. After weaning, half of the descendants were exposed for 6 months to the immunomodulating and tumor-promoting compound cyclosporine A (CsA) by diet, the others remained untreated. The animals were maintained for their entire lifespan, terminal sacrifices were carried out after 28 months. Complete autopsy was performed, and three protocol organs (lung, liver and spleen) were examined histologically, together with any suspicious lesions in other organs. Fertility and the lifetime of the maternal mice were reduced by the X-ray irradiation, and their incidence of lung and liver tumors was increased as compared to non-irradiated mice. The descendants of all groups revealed comparable body weights and mortality rates. The incidence of hematopoietic/lymphoreticular tissue tumors increased in the female hybrids by 6 months of CsA-treatment. A higher incidence of lung and liver tumors in the sham-treated male progeny of irradiated mothers was detected, pointing to a possible germ cell-transmitted alteration initiated by the preconceptual maternal X-ray exposure.

In-flight spraying in aircrafts: determination of the exposure scenario.

Exposure measurements were carried out in parked aircrafts during and after application of a biocide aerosol spray (simulated in-flight spraying). The aerosol product SRA spray (Standard Reference Aerosol Spray) was used for spraying. Concentrations of the pyrethrins--the active ingredients--in the air of the passenger cabin (airborne particles, measured during spray application and 40 minutes afterwards) varied from 11 to 65 microg/m3; those of the synergist piperonyl butoxide were 200-485 microg/m3. The concentrations on surfaces of the cabin furniture differed widely. Low concentrations were determined on surfaces in vertical positions (median values: pyrethrins < or =2 ng/cm2; piperonyl butoxide < or =17 ng/cm2), while under seats, on seats and on headrests the concentrations were up to 55.5 ng/cm2 for pyrethrins and 1162.5 ng/cm2 for piperonyl butoxide (median values). The inhaled doses for sprayers (using 100 g of spray) and persons sitting in the passenger cabin were calculated to be 17 microg for pyrethrins and 200 microg for piperonyl butoxide (maximum values). Maximum total external body doses for the applicators during spraying were 830 microg for pyrethrins and 8840 microg for piperonyl butoxide. The potential dermal dose for persons sitting in the passenger cabin was about a factor of two lower.

Carcinogenicity study of GSM and DCS wireless communication signals in B6C3F1 mice.

The purpose of this study using a total of 1170 B6C3F1 mice was to detect and evaluate possible carcinogenic effects in mice exposed to radio-frequency-radiation (RFR) from Global System for Mobile Communication (GSM) and Digital Personal Communications System (DCS) handsets as emitted by handsets operating in the center of the communication band, that is, at 902 MHz (GSM) and 1747 MHz (DCS). Restrained mice were exposed for 2 h per day, 5 days per week over a period of 2 years to three different whole-body averaged specific absorption rate (SAR) levels of 0.4, 1.3, 4.0 mW/g bw (SAR), or were sham exposed. Regarding the organ-related tumor incidence, pairwise Fisher's test did not show any significant increase in the incidence of any particular tumor type in the RF exposed groups as compared to the sham exposed group. Interestingly, while the incidences of hepatocellular carcinomas were similar in EMF and sham exposed groups, in both studies the incidences of liver adenomas in males decreased with increasing dose levels; the incidences in the high dose groups were statistically significantly different from those in the sham exposed groups. Comparison to published tumor rates in untreated mice revealed that the observed tumor rates were within the range of historical control data. In conclusion, the present study produced no evidence that the exposure of male and female B6C3F1 mice to wireless GSM and DCS radio frequency signals at a whole body absorption rate of up to 4.0 W/kg resulted in any adverse health effect or had any cumulative influence on the incidence or severity of neoplastic and non-neoplastic background lesions, and thus the study did not provide any evidence of RF possessing a carcinogenic potential.