Biomedical subjects

Anne Peters

Publications and source records attributed to Anne Peters.

4 recordsLinked to original sources

PubMed2006

Gender differences in stroke care decision-making.

BACKGROUND: Women are less likely than men to receive some stroke care interventions. It is not known whether gender differences in patient preferences explain some of the observed variations in stroke care delivery. METHODS: Outpatients with and without a history of cerebrovascular disease were recruited from stroke, vascular, and general internal medicine ambulatory clinics between September 2002 and October 2003. Self-administered surveys described hypothetical scenarios, and participants were asked if they would accept therapy with thrombolysis for acute ischemic stroke or carotid endarterectomy for secondary stroke prevention. The surveys also included questions on sociodemographic factors and decision-making preferences. RESULTS: A total of 586 patients (45% women) completed the survey. Women were less likely than men to accept thrombolysis (79% vs. 86%, P=0.014), even after adjustment for other factors (adjusted odds ratio [OR] 0.58, 95% confidence interval [CI] 0.37-0.92). Women and men were equally likely to accept carotid endarterectomy (82% vs. 84%, P=0.502), even after adjustment for other factors (adjusted OR 0.94, 95% CI 0.58- 1.53). Women were less confident in their decisions, were more risk averse, and would have preferred more information to assist them in their decision-making. CONCLUSIONS: No gender differences were found in patient preferences for carotid surgery. However, we observed gender differences in patient preferences for thrombolysis and in general attitudes toward stroke care decision-making. Health care providers should be aware that, compared with men, women may be more concerned about risks and may require more information before they make a decision.

Data Collection↗

PubMed2006

Prawn-in-a-tube procedure: habituation or associative learning in cuttlefish?

The prawn-in-a-tube procedure (J. B. Messenger, 1973a) has been used almost exclusively to study associative learning in cuttlefish. In two experiments, the authors sought to determine whether the decline in attack responses observed in this procedure was best accounted for by habituation or associative learning. Results of Experiment 1 revealed an asymmetrical stimulus-specificity effect that could be interpreted as either an instance of habituation or of associative learning. Results of Experiment 2 demonstrated that the response decline could not be reversed following the presentation of a dishabituatory stimulus. The combined results of these experiments support the conclusion that the response decline is best viewed as a resulting of associative processes. The authors considered whether the response decline represents extinction or passive avoidance.

Animals↗

PubMed2004

Trade-offs between immune investment and sexual signaling in male mallards.

Allocation trade-offs between the immune system and sexual traits are central to current sexual selection hypotheses but remain contentious. Such trade-offs could be brought about by the dual action of testosterone that stimulates sexual signals but also suppresses immune functions and/or by competition for carotenoids that can be deposited in ornaments or used as antioxidants in support of immune functions. We investigated the trade-off between investment in immunity and maintenance of testosterone, carotenoids, and sexually selected, carotenoid-based bill color in male mallards. Following a nonpathogenic immune challenge, facultative immune investment resulted in a syndrome of changes in allocation. Plasma carotenoids disappeared from circulation proportional to antibody production. In addition, the reflectance spectrum of the bill was affected; greater antibody production was associated with an increase in relative UV reflectance. Although changes in bill reflectance and plasma carotenoids were related, the relationship appeared more complex than direct competition with immunity. Finally, maintenance of testosterone was affected by immune investment: testosterone levels declined substantially when males produced more antibodies. Because males with high testosterone are preferred by females, the decline in testosterone, in addition to carotenoid depletion and effects on bill reflectance, could constitute a significant cost of immune investment.

Adaptation, Physiological↗

PubMed2003

Paternity analysis reveals opposing selection pressures on crown coloration in the blue tit (Parus caeruleus).

In socially monogamous species, extra-pair paternity can increase the variance in reproductive success and thereby the potential for sexual selection on male ornaments. We studied whether male secondary sexual ornaments are selected through within- and/or extra-pair reproductive success in the blue tit (Parus caeruleus). Male blue tits display a bright blue crown plumage, which reflects substantially in the ultraviolet (UV) and previously has been indicated to be an important sexual signal. We show that males with a more UV-shifted crown hue were less cuckolded, which probably resulted from female preference for more ornamented mates. By contrast, however, older males and males with a less UV-shifted hue sired more extra-pair young. This probably did not reflect direct female preference, since cuckolders were not less UV-ornamented than the males they cuckolded. Alternatively, a trade-off between UV ornamentation and other traits that enhance extra-pair success could explain this pattern. Our results might reflect two alternative male mating tactics, where more UV-ornamented males maximize within-pair success and less UV-ornamented males maximize extra-pair success. Since crown colour was selected in opposite directions by within-pair and extra-pair paternity, directional selection through extra-pair matings seemed weak, at least in this population and breeding season. Reduced intensity of sexual selection due to alternative mating tactics constitutes a potential mechanism maintaining additive genetic variance of male ornaments.

Animals↗