Cytogenetic tests for animal production: state of the art and perspectives.

Cytogenetic tests are effective tools for monitoring the health status of livestock and improving their genetic value. Cytogenetic screening allows for the detection of animals carrying chromosomal aberrations and to avoid using them as breeders. Progress in karyotype monitoring, with new molecular probes and automation, has greatly increased the productivity of this procedure. Several genotoxicity tests are available to detect the possible presence and effects of pollutants or drugs. Among these, the micronucleus test and the Comet assay are the most convenient in terms of costs and benefits. Finally, analysis of telomeres, the end of chromosomes and markers of genomic instability, may be developed into a new marker of stress and genetic value.

Use of EPR and FTIR to detect biological effects of ultrasound and microbubbles on a fibroblast cell line.

Structural and functional effects of exposing murine fibroblasts (NIH 3T3) to therapeutic ultrasound at 1 MHz frequency are described. These bioeffects can be attributed to the formation of free radical species by sonolysis of water. When cavitation occurs, dissociation of water vapor into H atoms and OH radicals is observed; these H atoms and OH radicals combine to form H(2), H(2)O(2), and HO(2). The radicals can chemically modify biomolecules, for example enzymes, DNA, and lipids. Generation of free radicals during exposure to ultrasound with or without encapsulated microbubbles (contrast agents) was studied by use of electron paramagnetic resonance with DMPO spin trapping. Recently the potential for possible use of these microbubbles in gene therapy has been investigated, because of the ability of the stabilized microbubbles to release their content when exposed to ultrasound. Structural changes were studied by Fourier-transform infrared spectroscopy, and induction of possible genotoxic damage by exposure of the cells to therapeutic ultrasound at 1 MHz frequency with our experimental device was verified by use of the cytokinesis-block micronucleus assay.

Clastogenicity and aneuploidy in newborn and adult mice exposed to 50 Hz magnetic fields.

PURPOSE: To detect possible clastogenic and aneugenic properties of a 50 Hz, 650 muT magnetic field. MATERIALS AND METHODS: The micronucleus test with CREST (Calcinosis, Raynaud's phenomenon, Esophageal dismotility, Sclerodactility, Telangectasia) antibody staining was performed on liver and peripheral blood sampled from newborn mice exposed to an ELF (Extremely Low Frequency) magnetic field during the whole intra-uterine life (21 days), and on bone marrow and peripheral blood sampled from adult mice exposed to the same magnetic field for the same period. RESULTS: Data obtained in newborn mice show a significant increase in micronuclei frequencies. In absolute terms, most of the induced micronuclei were CREST-negative (i.e., formed by a chromosome fragment). However, in relative terms, ELF exposure caused a two-fold increase in CREST-negative micronuclei and a four-fold increase in CREST-positive micronuclei (i.e., formed by a whole chromosome). No significant effect was recorded on exposed adults. CONCLUSIONS: These findings suggest the need for investigation of aneugenic properties of ELF magnetic fields in order to establish a possible relationship to carcinogenesis.

Micronucleus test on Triturus carnifex as a tool for environmental biomonitoring.

The amphibian micronucleus test has been widely used during the last 30 years to test the genotoxic properties of several chemicals and as a tool for ecogenotoxic monitoring. The vast majority of these studies were performed on peripheral blood of urodelan larvae and anuran tadpoles and to a lesser extent adults were also used. In this study, we developed protocols for measuring micronuclei in adult shed skin cells and larval gill cells of the Italian crested newt (Triturus carnifex). Amphibians were collected from ponds in two protected areas in Italy that differed in their radon content. Twenty-three adult newts and 31 larvae were captured from the radon-rich pond, while 20 adults and 27 larvae were taken from the radon-free site. The animals were brought to the laboratory and the micronucleus test was performed on peripheral blood and shed skins taken from the adults and on larval gills. Samples from the radon-rich site showed micronucleus frequencies higher than those from the radon-free site and the difference was statistically significant in gill cells (P < 0.00001). Moreover, the larval gills seem to be more sensitive than the adult tissues. This method represents an easy (and noninvasive in the case of the shed skin) application of the micronucleus assay that can be useful for environmental studies in situ.