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Purpose: The possibility of genotoxicity of radiofrequency radiation (RFR) applied alone or in combination with x-rays was investigated in vitro using several assays on human lymphocytes. The chosen specific absorption rate (SAR) values are near the upper limit of actual energy absorption in localized tissue when persons use some cellular telephones. The purpose of the combined exposures was to examine whether RFR might act epigenetically by reducing the fidelity of repair of DNA damage caused by a well-characterized and established mutagen. Methods: Blood specimens from 14 donors were exposed continuously for 24 h to a Global System for Mobile Communications (GSM) basic 935 MHz signal. The signal was applied at two SAR; 1 and 2 W/Kg, alone or combined with a 1-min exposure to 1.0 Gy of 250 kVp x-rays given immediately before or after the RFR. The assays employed were the alkaline comet technique to detect DNA strand breakage, metaphase analyses to detect unstable chromosomal aberrations and sister chromatid exchanges, micronuclei in cytokinesis-blocked binucleate lymphocytes and the nuclear division index to detect alterations in the speed of in vitro cell cycling. Results: By comparison with appropriate sham-exposed and control samples, no effect of RFR alone could be found for any of the assay endpoints. In addition RFR did not modify any measured effects of the x-radiation. Conclusions: This study has used several standard in vitro tests for chromosomal and DNA damage in Go human lymphocytes exposed in vitro to a combination of x-rays and RFR. It has comprehensively examined whether a 24-h continuous exposure to a 935 MHz GSM basic signal delivering SAR of 1 or 2 W/Kg is genotoxic per se or whether, it can influence the genotoxicity of the well-established clastogenic agent; x-radiation. Within the experimental parameters of the study in all instances no effect from the RFR signal was observed. [ABSTRACT FROM AUTHOR]

The impact of demographic, lifestyle, and seminal factors on the sperm chromatin structure assay (SCSA) parameters was evaluated in a population of 277 healthy Danish men. This cohort was established within the framework of a European Concerted Action on occupational hazards to male reproductive capability in order to examine the possible reproductive effects of exposure to styrene or pesticides. The SCSA measures the susceptibility of sperm DNA to in-situ acid-induced denaturation, by multiparameter flow cytometric analysis after staining with the DNA-specific fluorescent dye acridine orange. The green versus red bivariate cytogram patterns were quite variable among donors, showing a wide heterogeneity of sperm DNA denaturability. Nevertheless, in those cases where we had the possibility to measure two semen samples from the same donor, the cytogram pattern remained stable over time (0.64 < r < 0.78). Analysis of variance demonstrated that the SCSA results can be influenced by the age of the donor (P < 0.0001), smoking habits (P < 0.05), the presence of leukocytes and immature germ forms in the ejaculate (P < 0.0001), and the duration of sexual abstinence (P < 0.0001). Furthermore, the relationship between the SCSA data and sperm concentration, morphology, and vitality was weak (-0.22 < r < -0.46). Therefore, the SCSA provides independent and complementary measurements of semen quality and is thus a useful tool for epidemiological studies, but the effects of some confounders should be accounted for in the survey design and analysis. [ABSTRACT FROM PUBLISHER]

The sperm chromatin structure assay (SCSA) is a flow cytometric (FCM) technique which exploits the metachromatic properties of Acridine Orange to monitor the susceptibility of sperm chromatin DNA to insitu acid denaturation. SCSA was used to study the chromatin structure variations of human spermatozoa in semen, both before and after swim-up and after cryopreservation. Semen samples were provided by 19 healthy normozoospermic subjects attending pre-marriage checks. Each sample was divided into three aliquots: the first aliquot was evaluated without further treatment, the second underwent swim-up, and the third was stored according to standard cryopreservation techniques in liquid nitrogen at –196°C. Samples were also analysed by light and fluorescence microscopy (after Acridine Orange staining to evaluate the number of green fluorescent sperm heads), and by computer-assisted semen analysis. The results showed that post-rise spermatozoa represent a subpopulation characterized by a general improvement of the morphological (reduction of the percentage of abnormal forms and heads, increase of the green head sperm percentage) and kinetic parameters. This subpopulation also exhibited improved chromatin structure properties, confirming that these cells have the best structural and functional characteristics, indicative of optimal fertilizing ability. On the other hand, overall sperm quality deteriorates after cryopreservation. When thawed spermatozoa underwent an additional swim-up round, a general improvement of nuclear maturity was seen in the post-rise spermatozoa. [ABSTRACT FROM AUTHOR]