Possible attenuation of the G2 DNA damage cell cycle checkpoint in HeLa cells by extremely low frequency (ELF) electromagnetic fields

BACKGROUND: The issue remains unresolved as to whether low frequency magnetic fields can affect cell behaviour, with the possibility that they may be in part responsible for the increased incidence of leukaemia in parts of the population exposed to them. METHODS: Combined treatment of HeLa cells with gamma-irradiation (1, 3 and 5 Grays) and extra low frequency magnetic fields of ~50 Hz was carried out under rigorously controlled conditions. RESULTS: Synchronised cells progressing from S-phase arrived at mitosis on average marginally ahead of irradiation controls not exposed to ELF. In no instance out of a total of twenty separate experiments did this "double-insult" further delay entry of cells into mitosis, as had been anticipated. CONCLUSION: This apparently "non-genotoxic" agent (ELF) appears to be capable of affecting cells that would normally arrest for longer in G2, suggesting a weakening of the stringency of the late cycle (G2) checkpoint

Nepotistic patterns of violent psychopathy: evidence for adaptation?

Psychopaths routinely disregard social norms by engaging in selfish, antisocial, often violent behavior. Commonly characterized as mentally disordered, recent evidence suggests that psychopaths are executing a well-functioning, if unscrupulous strategy that historically increased reproductive success at the expense of others. Natural selection ought to have favored strategies that spared close kin from harm, however, because actions affecting the fitness of genetic relatives contribute to an individual’s inclusive fitness. Conversely, there is evidence that mental disorders can disrupt psychological mechanisms designed to protect relatives. Thus, mental disorder and adaptation accounts of psychopathy generate opposing hypotheses: psychopathy should be associated with an increase in the victimization of kin in the former account but not in the latter. Contrary to the mental disorder hypothesis, we show here in a sample of 289 violent offenders that variation in psychopathy predicts a decrease in the genetic relatedness of victims to offenders; that is, psychopathy predicts an increased likelihood of harming non-relatives. Because nepotistic inhibition in violence may be caused by dispersal or kin discrimination, we examined the effects of psychopathy on (1) the dispersal of offenders and their kin and (2) sexual assault frequency (as a window on kin discrimination). Although psychopathy was negatively associated with coresidence with kin and positively associated with the commission of sexual assault, it remained negatively associated with the genetic relatedness of victims to offenders after removing cases of offenders who had coresided with kin and cases of sexual assault from the analyses. These results stand in contrast to models positing psychopathy as a pathology, and provide support for the hypothesis that psychopathy reflects an evolutionary strategy largely favoring the exploitation of non-relatives

The impact of nonresponse on the unemployment rate in the Current Population Survey (CPS)

Gegenstand der Untersuchung sind CPS-Daten für alle Monate zwischen Januar 1994 und Juni 1997. Dabei wurden auch Antwortverweigerung und -ausfälle untersucht, um den Wechsel von Personen von der Nicht-Beteiligung zur Beteiligung am CPS und die Auswirkungen auf die Schätzung des Erwerbspersonenpotenzials zu untersuchen. Personen, die sich in einem Monat nicht am CPS beteiligten, wiesen höhere Quoten bei Arbeitslosigkeit, Erwerbsbeteiligung und Beschäftigung auf als Befragte, die sich in zwei aufeinander folgenden Monaten an der Umfrage beteiligten. Es traten auch - wenn auch in geringem Umfang - signifikante positive Korrelationen zwischen den Unterschieden in den Arbeitslosenquoten und der Antwortverweigerung insgesamt im Rahmen des CPS zu Tage. Zudem wurden Unterschiede hinsichtlich bestimmter Merkmale der Erwerbstätigkeit zwischen Antwortverweigerern und Nichtangetroffenen sichtbar. (ICEÜbers)"In the present research authors matched CPS data from all consecutive months from January, 1994 to June, 1997 and conducted an analysis similar to a gross flows analysis that included nonrespondents to examine the 'flow' of persons from respondent to nonrespondent status in the CPS and the resulting effect an labor force estimates. Persons who were nonrespondents to the CPS one month had higher rates of unemployment, labor force participation, and employment than those who were respondents both months. There were also moderate, but significant positive correlations between the differences an unemployment rates and the overall level of nonresponse in the CPS. There were also some differences in labor force characteristics between refusals and noncontacts." (author's abstract

Longitudinal nonresponse in the Current Population Survey (CPS)

Es wurde eine Datenbank mit Längsschnittdaten aufgebaut, die aus sieben vollständigen "Kohorten" bestand, von denen jede über eine Periode von fast zwei Jahren in allen acht Monaten in der CPS-Stichprobe war. Verglichen wurden Fälle vollständiger und teilweiser Beantwortung. Haushalte mit vollständiger Beantwortung lagen eher in ländlichen Gebieten, nicht im Westen der USA, umfassten mehr Personen und wurden von den Hauseigentümern selbst bewohnt. Mitglieder dieser Haushalte waren eher verheiratet, Kinder, Weiße, nicht spanischstämmig, über 65 Jahre alt und beantworteten mit höherer Wahrscheinlichkeit eine Frage nach dem Familieneinkommen. Personen in Haushalten mit teilweiser Beantwortung wiesen in den ersten vier Stichprobenmonaten (MIS) ein höheres Beschäftigungsniveau und in MIS 1 eine höhere Arbeitslosenquote auf als Personen in Haushalten mit vollständiger Beantwortung. (ICEÜbers)"A longitudinal database was created consisting of seven complete 'cohorts' who were in the CPS sample all eight months over nearly a 2 year period. Comparisons were made among complete respondents and partial respondents. Households that were complete respondents were relatively more likely than households that were partial respondents to be located in rural areas and in any region of the country except the west, and to have more persons living there, and to be occupied by owners. Members of complete respondent households were relatively more likely than members of partial respondent households to be a married couple, children, white, non-Hispanic, over 65 years of age, and were relatively more likely to answer a question an total family income. Persons in partial respondent households had a higher level of employment in the first four months-in-sample (MIS) and a higher unemployment rate in MIS 1 than persons in complete respondent households." (author's abstract

The influence of a surfactant, linear alkylbenzene sulfonate, on the estrogenic response to a mixture of (xeno)estrogens in vitro and in vivo

This is the post-print version of the final paper published in Aquatic Toxicology. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright © 2008 Elsevier B.V. All rights reserved.The effect of the presence of a surfactant on the activity of a mixture of environmental estrogens was assessed. In their natural habitat, fish are subject not only to exposure to mixtures of estrogenic compounds, as has been addressed in previous publications, but also to other confounding factors (chemical, physical and biological), which may, in theory, affect their responses to such compounds. To assess the potential for such interference, the commonly occurring surfactant, linear alkylbenzene sulfonate (LAS), was applied to the yeast estrogen screen at various concentrations, independently and together with a mixture of estrogens at constant concentrations. LAS enhanced the estrogenic activity of the mixture, an effect which became less pronounced over the course of time. This information was used to design an in vivo study to assess induction of vitellogenin in fathead minnows exposed to the same mixture of estrogens plus LAS. A similar trend was observed, that is, the response was enhanced, but the effect became less pronounced as the study progressed. However, the enhanced response in vivo occurred only at the highest concentration of LAS tested (362 μg/L), and was transient because it was no longer apparent by the end of the study. Although LAS is a significant contaminant in terms of both concentration and frequency of detection in the aquatic environment, these data do not suggest that it will have a significant impact on the response of fish to environmental estrogens

Steric regulation of tandem calponin homology domain actin-binding affinity.

Tandem calponin homology (CH1-CH2) domains are common actin-binding domains in proteins that interact with and organize the actin cytoskeleton. Despite regions of high sequence similarity, CH1-CH2 domains can have remarkably different actin-binding properties, with disease-associated point mutants known to increase as well as decrease affinity for F-actin. To investigate features that affect CH1-CH2 affinity for F-actin in cells and in vitro, we perturbed the utrophin actin-binding domain by making point mutations at the CH1-CH2 interface, replacing the linker domain, and adding a polyethylene glycol (PEG) polymer to CH2. Consistent with a previous model describing CH2 as a steric negative regulator of actin binding, we find that utrophin CH1-CH2 affinity is both increased and decreased by modifications that change the effective "openness" of CH1 and CH2 in solution. We also identified interface mutations that caused a large increase in affinity without changing solution "openness," suggesting additional influences on affinity. Interestingly, we also observe nonuniform subcellular localization of utrophin CH1-CH2 that depends on the N-terminal flanking region but not on bulk affinity. These observations provide new insights into how small sequence changes, such as those found in diseases, can affect CH1-CH2 binding properties

Neutralising antibody response in domestic cats immunised with a commercial feline immunodeficiency virus (FIV) vaccine

Across human and veterinary medicine, vaccines against only two retroviral infections have been brought to market successfully, the vaccines against feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV). FeLV vaccines have been a global success story, reducing virus prevalence in countries where uptake is high. In contrast, the more recent FIV vaccine was introduced in 2002 and the degree of protection afforded in the field remains to be established. However, given the similarities between FIV and HIV, field studies of FIV vaccine efficacy are likely to advise and inform the development of future approaches to HIV vaccination.<p></p> Here we assessed the neutralising antibody response induced by FIV vaccination against a panel of FIV isolates, by testing blood samples collected from client-owned vaccinated Australian cats. We examined the molecular and phenotypic properties of 24 envs isolated from one vaccinated cat that we speculated might have become infected following natural exposure to FIV. Cats vaccinated against FIV did not display broadly neutralising antibodies, suggesting that protection may not extend to some virulent recombinant strains of FIV circulating in Australia.<p></p&gt