| 1. |
- Dahlöf, Björn, 1953, et al.
(författare)
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Population impact of losartan use on stroke in the European Union (EU): projections from the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study
- 2004
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Ingår i: J Hum Hypertens. - 0950-9240. ; 18:6, s. 367-73
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Tidskriftsartikel (refereegranskat)abstract
- The Losartan Intervention for Endpoint reduction in hypertension (LIFE) study was designed to compare losartan- vs atenolol-based antihypertensive treatment on cardiovascular morbidity and mortality in a population of 9193 hypertensive patients with left ventricular hypertrophy (LVH). In LIFE, the losartan-based treatment further reduced the primary composite end point (cardiovascular death, myocardial infarction, or stroke) by 13% (risk reduction (RR) 0.87, 95% confidence interval (CI) 0.77-0.98, P=0.021). The further reduction in stroke with losartan (RR 0.75, 95% CI 0.63-0.89, P=0.001) was the major contributing factor to the reduction in the primary end point. Our objective was to project the reduction in stroke observed with a losartan- vs an atenolol-based antihypertensive treatment regimen in the LIFE study to the European Union (EU) population. The number of stroke events averted was estimated by identifying the number of persons in the EU expected to meet the LIFE inclusion criteria, and multiplying this figure by the cumulative incidence risk difference in stroke from LIFE at 5.5 years. The age- and gender-specific prevalence of hypertension, electrocardiographically (ECG)-diagnosed LVH among those with hypertension (inclusion criteria), and heart failure among those with LVH and hypertension (exclusion criteria) were applied to the EU census estimates. We conservatively projected that an estimated 7.8 million individuals aged 55-80 years in the EU are affected by hypertension and ECG-diagnosed LVH. Use of a losartan-based antihypertensive treatment in this population is projected to prevent approximately 125 000 first strokes over a 5.5-year period. A population-wide prevention strategy of using losartan in patients with LVH and hypertension has the potential to have a major public health impact by reducing the morbidity and mortality of stroke in the EU.
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| 2. |
- Komdeur, J, et al.
(författare)
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Experimental evidence that kin discrimination in the Seychelles warbler is based on association and not on genetic relatedness
- 2004
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Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 271:1542, s. 963-969
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Tidskriftsartikel (refereegranskat)abstract
- In cooperative breeding systems driven by kin selection, effective kin-recognition cues are important. Recognition could be achieved by the direct assessment of the genetic relatedness of individuals or by learning through association. In the Seychelles warbler, Acrocephalus sechellensis, female subordinates maximize indirect fitness by preferentially helping genetically related nestlings. Help seems to be based on the continued presence of the primary female who previously fed the subordinate in the nest but it has, so far, been impossible to discount the direct assessment of genetic relatedness. We used a cross-fostering experiment to separate the two possible cues. Adult birds did not discriminate between their own and cross-fostered eggs or nestlings. Cross-fostering resulted in nestlings that were unrelated to the primary female that raised them, but control nestlings were closely related to their primary females. The proportions of cross-fostered and control female offspring that stayed and became helpers on their 'natal' territory were similar. However, for both groups the chance of becoming a subordinate helper was associated with the continued presence of the primary female and not with any other factor tested. Our study provides strong evidence that helping decisions are based on associative-learning cues.
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| 3. |
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| 4. |
- Petrie, M, et al.
(författare)
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Maternal investment: Sex differences in avian yolk hormone levels
- 2001
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 412, s. 498-
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Tidskriftsartikel (refereegranskat)abstract
- It has been suggested that female birds put more resources into eggs fathered by attractive males by laying larger eggs1 or by adding more testosterone2, but this inference could be undermined if eggs of different sex are provisioned differently, as these studies did not control for sex differences. Here we compare hormone concentrations in the yolks of male and female eggs and find that these are significantly different. Our results indicate that it is premature to conclude that female birds invest more in eggs sired by a preferred male, and raise the possibility that yolk sex steroids may be part of the sex-determining process in birds.
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| 5. |
- Richardson, David, et al.
(författare)
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Altruism and infidelity among warblers
- 2003
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 422:6932, s. 580-580
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Richardson, David, et al.
(författare)
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Direct benefits and the evolution of female-biased cooperative breeding in Seychelles warblers
- 2002
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Ingår i: Evolution. - : Wiley. - 1558-5646 .- 0014-3820. ; 56:11, s. 2313-2321
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Tidskriftsartikel (refereegranskat)abstract
- Inclusive fitness benefits have been suggested to be a major selective force behind the evolution of cooperative breeding. We investigated the fitness benefits selecting for cooperative breeding in the Seychelles warbler, Acroccphalus sechellensis. A microsatellite-based genotyping method was used to determine the relatedness of subordinates to group offspring in an isolated population of Seychelles warblers. The indirect and direct breeding benefits accruing to individual subordinates were then calculated for every successful breeding event over a three-year period. We show that female subordinates frequently gained parentage and that this, combined with high levels of extragroup paternity, resulted in low levels of relatedness between subordinates and nondescendent offspring within a territory. Direct breeding benefits were found to be significantly higher than indirect kin benefits for both female and male subordinates. As predicted, female subordinates gained significantly more direct breeding opportunities and therefore higher inclusive fitness benefits by being a subordinate within a group than did males. This may explain why most subordinates in the Seychelles warbler are female.
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| 7. |
- Richardson, David, et al.
(författare)
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Inbreeding in the seychelles warbler: Environment-dependent maternal effects
- 2004
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Ingår i: Evolution. - : Wiley. - 1558-5646 .- 0014-3820. ; 58:9, s. 2037-2048
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Tidskriftsartikel (refereegranskat)abstract
- The deleterious effects of inbreeding can be substantial in wild populations and mechanisms to avoid such matings have evolved in many organisms. In situations where social mate choice is restricted, extrapair paternity may be a strategy used by females to avoid inbreeding and increase offspring heterozygosity. In the cooperatively breeding Seychelles warbler, Acrocephalus sechellensis, neither social nor extrapair mate choice was used to avoid inbreeding facultatively, and close inbreeding occurred in approximately 5% of matings. However, a higher frequency of extra-group paternity may be selected for in female subordinates because this did reduce the frequency of mating between close relatives. Inbreeding resulted in reduced individual heterozygosity, which, against expectation, had an almost significant (P = 0.052). positive effect on survival. Conversely, low heterozygosity in the genetic mother was linked to reduced offspring survival, and the magnitude of this intergenerational inbreeding depression effect was environment-dependent. Because we controlled for genetic effects and most environmental effects (through the experimental cross-fostering of nestlings), we conclude that the reduced survival was a result of maternal effects. Our results show that inbreeding can have complicated effects even within a genetic bottlenecked population where the "purging'' of recessive alleles is expected to reduce the effects of inbreeding depression.
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| 8. |
- Richardson, David, et al.
(författare)
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Sex-specific associative learning cues and inclusive fitness benefits in the Seychelles warbler
- 2003
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Ingår i: Journal of evolutionary biology. - : Wiley. - 1420-9101 .- 1010-061X. ; 16:5, s. 854-861
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Tidskriftsartikel (refereegranskat)abstract
- In cooperative, breeding vertebrates, indirect fitness benefits would be maximized by subordinates that accurately assess their relatedness to group offspring and preferentially help more closely related kin. In the Seychelles warbler (Acrocephalus sechellensis), we found a positive relationship between subordinate-nestling kinship (determined using microsatellite marker genotypes) and provisioning rates, but only for female subordinates. Female subordinates that helped were significantly more related to the nestlings than were nonhelpers, and the decision to help appears to be based on associative learning cues. High levels of female infidelity means that subordinates cannot trust their legitimacy through the male line, consequently they appear to use the continued presence of the primary female, but not the primary male, as a reliable cue to determine when to feed nestlings. By using effective discrimination, female subordinates are able to maximize the indirect benefits gained within. a cooperative breeding system otherwise driven primarily by direct breeding benefits.
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