Radiosensitivity in breast cancer assessed by the Comet and micronucleus assays

Spontaneous and radiation-induced genetic instability of peripheral blood mononuclear cells derived from unselected breast cancer (BC) patients (n=50) was examined using the single-cell gel electrophoresis (Comet) assay and a modified G2 micronucleus (MN) test. Cells from apparently healthy donors (n=16) and from cancer patients (n=9) with an adverse early skin reaction to radiotherapy (RT) served as references. Nonirradiated cells from the three tested groups exhibited similar baseline levels of DNA fragmentation assessed by the Comet assay. Likewise, the Comet analysis of in vitro irradiated (5 Gy) cells did not reveal any significant differences among the three groups with respect to the initial and residual DNA fragmentation, as well as the DNA repair kinetics. The G2 MN test showed that cells from cancer patients with an adverse skin reaction to RT displayed increased frequencies of both spontaneous and radiation-induced MN compared to healthy control or the group of unselected BC patients. Two patients from the latter group developed an increased early skin reaction to RT, which was associated with an increased initial DNA fragmentation in vitro only in one of them. Cells from the other BC patient exhibited a striking slope in the dose–response curve detected by the G2 MN test. We also found that previous RT strongly increased both spontaneous and in vitro radiation-induced MN levels, and to a lesser extent, the radiation-induced DNA damage assessed by the Comet assay. These data suggest that clinical radiation may provoke genetic instability and/or induce persistent DNA damage in normal cells of cancer patients, thus leading to increased levels of MN induction and DNA fragmentation after irradiation in vitro. Therefore, care has to be taken when blood samples collected postradiotherapeutically are used to assess the radiosensitivity of cancer patients

Spontaneous and radiation-induced chromosomal instability and persistence of chromosome aberrations after radiotherapy in lymphocytes from prostate cancer patients

The aim of the study was to compare the spontaneous and ex vivo radiation-induced chromosomal damage in lymphocytes of untreated prostate cancer patients and age-matched healthy donors, and to evaluate the chromosomal damage, induced by radiotherapy, and its persistence. Blood samples from 102 prostate cancer patients were obtained before radiotherapy to investigate the excess acentric fragments and dicentric chromosomes. In addition, in a subgroup of ten patients, simple exchanges in chromosomes 2 and 4 were evaluated by fluorescent in situ hybridization (FISH), before the onset of therapy, in the middle and at the end of therapy, and 1 year later. Data were compared to blood samples from ten age-matched healthy donors. We found that spontaneous yields of acentric chromosome fragments and simple exchanges were significantly increased in lymphocytes of patients before onset of therapy, indicating chromosomal instability in these patients. Ex vivo radiation-induced aberrations were not significantly increased, indicating proficient repair of radiation-induced DNA double-strand breaks in lymphocytes of these patients. As expected, the yields of dicentric and acentric chromosomes, and the partial yields of simple exchanges, were increased after the onset of therapy. Surprisingly, yields after 1 year were comparable to those directly after radiotherapy, indicating persistence of chromosomal instability over this time. Our results indicate that prostate cancer patients are characterized by increased spontaneous chromosomal instability. This instability seems to result from defects other than a deficient repair of radiation-induced DNA double-strand breaks. Radiotherapy-induced chromosomal damage persists 1 year after treatment

Spermatozoal sensitive biomarkers to defective protaminosis and fragmented DNA

Human sperm DNA damage may have adverse effects on reproductive outcome. Infertile men possess substantially more spermatozoa with damaged DNA compared to fertile donors. Although the extent of this abnormality is closely related to sperm function, the underlying etiology of ensuing male infertility is still largely controversial. Both intra-testicular and post-testicular events have been postulated and different mechanisms have been proposed to explain the presence of damaged DNA in human spermatozoa. Three among them, i.e. abnormal chromatin packaging, oxidative stress and apoptosis, are the most studied and discussed in the present review. Furthermore, results from numerous investigations are presented, including our own findings on these pathological conditions, as well as the techniques applied for their evaluation. The crucial points of each methodology on the successful detection of DNA damage and their validity on the appraisal of infertile patients are also discussed. Along with the conventional parameters examined in the standard semen analysis, evaluation of damaged sperm DNA seems to complement the investigation of factors affecting male fertility and may prove an efficient diagnostic tool in the prediction of pregnancy outcome

Étude géophysique et paléogéographique de l’Agora de Thasos (Grèce) : implications pour l’occupation humaine durant l’Antiquité

Le secteur occupé par les ruines de l’agora antique de Thasos (île de Thasos, Grèce), point bas de la ville antique, fait régulièrement l’objet d’inondations entraînant un risque de dégradation des vestiges visibles et enfouis. Un programme d’étude pluridisciplinaire a été entrepris, visant dans un premier temps à caractériser la nature du sous-sol (objet de cette contribution) et dans un second temps, à proposer des solutions pour l’assèchement de l’agora. Une étude géophysique comprenant notamment six profils de tomographie de résistivité électrique a été complétée par la réalisation de six carottages afin de révéler la géométrie des structures sous-jacentes et des strates sédimentaires. L’histoire de l’occupation de la zone côtière du site est relativement récente puisque les traces de fréquentation de cette zone basse ne remontent pas au-delà de l’époque archaïque (VIIe siècle av. J.-C.). L’existence d’une ancienne baie marine à cet emplacement a souvent été évoquée, mais jamais démontrée, par les archéologues pour justifier une fréquentation assez récente. Dans un sous-sol très conducteur, les profils de tomographie de résistivité électrique révèlent tout de même un niveau plutôt résistif (> 50 Ω.m) situé entre 0,5 et 2 m de profondeur, mais dont l’épaisseur varie : il pourrait s’agir de la base du niveau d’occupation. L’étude malacologique des six carottages et la datation par le radiocarbone du carottage Thasos 1 démontrent l’existence d’un environnement marin aux alentours du VIIe siècle av. J.-C. et seuls les deux carottages localisés au pied de la colline sud, notamment à proximité du passage des Théores, n’ont pas permis d’identifier les dépôts de cette ancienne baie marine

The rising threat of climate change for arthropods from Earth’s cold regions: Taxonomic rather than native status drives species sensitivity

Polar and alpine regions are changing rapidly with global climate change. Yet the impacts on biodiversity, especially on the invertebrate ectotherms which are dominant in these areas, remain poorly understood. Short-term extreme temperature events, which are growing in frequency, are expected to have profound impacts on high-latitude ectotherms, with native species being less resilient than their alien counterparts. Here, we examined in the laboratory the effects of short periodic exposures to thermal extremes on survival responses of seven native and two non-native invertebrates from the sub-Antarctic Islands. We found that survival of dipterans was significantly reduced under warming exposures, on average having median lethal times (LT50) of about 30 d in control conditions, which declined to about 20 d when exposed to daily short-term maxima of 24°C. Conversely, coleopterans were either not, or were less, affected by the climatic scenarios applied, with predicted LT50 as high as 65 d under the warmest condition (daily exposures at 28 °C for 2 h). The native spider Myro kerguelensis was characterized by an intermediate sensitivity when subjected to short-term daily heat maxima. Our results unexpectedly revealed a taxonomic influence, with physiological sensitivity to heat differing between higher level taxa, but not between native and non-native species representing the same higher taxon. The survival of a non-native carabid beetle under the experimentally imposed conditions was very high, but similar to that of native beetles, while native and non-native flies also exhibited very similar sensitivity to warming. As dipterans are a major element of diversity of sub-Antarctic, Arctic and other cold ecosystems, such observations suggest that the increased occurrence of extreme, short-term, thermal events could lead to large scale restructuring of key terrestrial ecosystem components both in ecosystems protected from and those exposed to the additional impacts of biological invasions

Geoarchaeology of Ancient Aulis (Boeotia, Central Greece): Human occupation and Holocene landscape changes

This article presents the results of a coring operation which brought to light new evidence for the evolution of the coastal plain of Aulis (Boeotia, Central Greece) in the Holocene. Thanks to Homer, Aulis is best known as the gathering point of the Achaean fleet before it sailed to Troy and a sanctuary of the goddess Artemis. Ancient sources and archaeological evidence suggest the presence of an ancient marine bay, potentially used as a harbor. In the course of investigation, we drilled two cores, to a maximum depth of 4.20 m in the marshy lowlands and performed mollusc and micro-paleontological identifications, laser grain size analyses, and magnetic susceptibility measurements in order to reveal the facies evolution of the area. We obtained a chronostratigraphy sequence through a series of seven AMS 14C radiocarbon dates. Our study shows that the area was affected by a shallow marine incursion from the first half of the 6th millennium BC and gradually turned into a succession of shallow marine/lagoon environments from ca. 5000 cal. BC to the 2nd Century AD, and into a confined lagoon environment during the Roman and Byzantine periods. © 2012 Elsevier Ltd