| 1. |
- Andersson, Staffan, 1959, et al.
(författare)
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Effects of egg yolk testosterone on growth and immunity in a precocial bird
- 2004
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X. ; 17:3, s. 501-505
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Tidskriftsartikel (refereegranskat)abstract
- In oviparous vertebrates, maternal steroid allocation to eggs can have important fitness consequences for the offspring. However, elevated testosterone levels are not only associated with beneficial postnatal effects, such as enhanced growth and high social status, but may also entail costs by suppressing the immune system. In this study, testosterone levels in eggs of Chinese painted quail (Coturnix chinensis) were experimentally manipulated to evaluate its effects on growth and immunocompetence. Testosterone did not affect embryonic development, body size or growth during the first 20 days. However, elevated testosterone levels during embryonic development were immunosuppressive for chicks with inherently higher growth rate. Adaptive scenarios where only beneficial effects of increased testosterone levels are considered may therefore need to be re-evaluated.
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| 2. |
- Erjefält, Jonas, et al.
(författare)
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Rapid and efficient clearance of airway tissue granulocytes through transepithelial migration.
- 2004
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Ingår i: Thorax. - : BMJ. - 1468-3296 .- 0040-6376. ; 59:2, s. 136-143
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Tidskriftsartikel (refereegranskat)abstract
- Background: Clearance of tissue granulocytes is central to the resolution of airway inflammation. To date the focus has been on apoptotic mechanisms of cell removal and little attention has been given to alternative processes. The present study explores transepithelial migration as a mechanism of cell clearance. Method: Guinea pig tracheobronchial airways where eosinophils are constitutively present in the mucosal tissue were studied. A complex topical stimulus (allergen challenge) was applied and the fate of the eosinophils was determined by selective tracheobronchial lavage and histological examination of the tissue. Results: Within 10 minutes of the allergen challenge, massive migration of eosinophils into the airway lumen occurred together with a reduction in tissue eosinophil numbers. Cell clearance into the lumen continued at high speed and by 30 and 60 minutes the tissue eosinophilia had been reduced by 63% and 73%, respectively. The marked transepithelial migration (estimated maximal speed 35 000 cells/min x cm2 mucosal surface) took place ubiquitously between epithelial cells without affecting epithelial integrity as assessed by transmission and scanning electron microscopy. Eosinophil apoptosis was not detected but occasional cytolytic eosinophils occurred. Conclusion: This study shows that luminal entry has a remarkably high capacity as a granulocyte elimination process. The data also suggest that an appropriate stimulus of transepithelial migration may be used therapeutically to increase the resolution of inflammatory conditions of airway tissues.
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| 3. |
- Korsgren, Magnus, et al.
(författare)
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Role of macrophage migration inhibitory factor (MIF) in allergic and endotoxin-induced airway inflammation in mice
- 2000
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Ingår i: Mediators of Inflammation. - : Hindawi Limited. - 0962-9351 .- 1466-1861. ; 9:1, s. 15-23
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Tidskriftsartikel (refereegranskat)abstract
- Macrophage migration inhibitory factor (MIF) has recently been forwarded as a critical regulator of inflammatory conditions, and it has been hypothesized that MIF may have a role in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). Hence, we examined effects of MIF immunoneutralization on the development of allergen-induced eosinophilic inflammation as well as on lipopolysaccharide (LPS)-induced neutrophilic inflammation in lungs of mice. Anti-MIF serum validated with respect to MIF neutralizing capacity or normal rabbit serum (NRS) was administered i.p. repeatedly during allergen aerosol exposure of ovalbumin (OVA)-immunized mice in an established model of allergic asthma, or once before instillation of a minimal dose of LPS into the airways of mice, a tentative model of COPD. Anti-MIF treatment did not affect the induced lung tissue eosinophilia or the cellular composition of bronchoalveolar lavage fluid (BALF) in the asthma model. Likewise, anti-MIF treatment did not affect the LPS-induced neutrophilia in lung tissue, BALF, or blood, nor did it reduce BALF levels of tumor necrosis factor-alpha (TNF-alpha) and macrophage inflammatory protein-1alpha (MIP-1alpha). The present data suggest that MIF is not critically important for allergen-induced eosinophilic, and LPS-induced neutrophilic responses in lungs of mice. These findings do not support a role of MIF inhibition in the treatment of inflammatory respiratory diseases.
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| 4. |
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| 5. |
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| 6. |
- Olsson, Mats, 1960, et al.
(författare)
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Haldane rules: costs of outbreeding at production of daughters in sand lizards
- 2004
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 7:10, s. 924-928
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Tidskriftsartikel (refereegranskat)abstract
- Haldane's rule is one of the most widely applicable paradigms in evolutionary biology, stating that in species crossings, the heterogametic sex will suffer more severely in terms of sterility and inviability. We address this in a within-species outbreeding situation by assessing the risk of producing inviable offspring depending on the sex ratio of the clutch produced in between-population crossings in the laboratory. In crossings between male and female sand lizards (Lacerta agilis) from two different sampling regions, one in Sweden, one in central Europe, risk of gametic incompatibility is unaffected by outbreeding, but offspring from between-population crossings show 300% higher malformation frequency and 10% lower hatching success. The risk of having inviable offspring increases with the production of daughters, i.e. the hemizygous sex in this species (ZW). Such sex-specific genetic costs of offspring production need to be incorporated into life history ecology, e.g. sex allocation theory.
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| 7. |
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| 8. |
- Persson, Carl, et al.
(författare)
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Unbalanced research
- 2001
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Ingår i: Trends in Pharmacological Sciences. - 0165-6147. ; 22:10, s. 538-541
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Tidskriftsartikel (refereegranskat)
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| 9. |
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| 10. |
- Uller, Lena, et al.
(författare)
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Lung tissue eosinophils may be cleared through luminal entry rather than apoptosis: effects of steroid treatment
- 2001
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Ingår i: American Journal of Respiratory and Critical Care Medicine. - 1535-4970. ; 164:10, s. 1948-1956
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Tidskriftsartikel (refereegranskat)abstract
- Spontaneous or steroid-induced eosinophil apoptosis occurring in vitro has not been demonstrated in lung tissues in vivo. This study examines cell apoptosis in rat lungs using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) technique and transmission electron microscopy (TEM). After establishing sustained lung edema and eosinophilia by challenge with Sephadex beads intratracheally, budesonide treatment was started intratracheally. Sephadex alone increased the total number of apoptotic cells, which were not efficiently engulfed by macrophages or other cells, in vivo. Yet apoptotic tissue eosinophils were exceedingly rare (1 of 360 TEM-analyzed eosinophils). By contrast, approximately 20% of eosinophils in the airway lumen were apoptotic, and unengulfed. Budesonide promptly inhibited edema but 3 d of steroid treatment were required to reduce the established tissue eosinophilia. Not at any time point did budesonide induce eosinophil apoptosis (0 of 318 TEM-analyzed tissue eosinophils). We conclude that (1) eosinophil apoptosis can occur but is a rare event in vivo in respiratory tract tissues; (2) airway tissue eosinophils, rather than undergoing apoptosis, are eliminated by migration into airway lumen followed by apoptosis and mucociliary clearance; (3) anti-inflammatory steroid treatment may not increase eosinophil apoptosis in vivo nor may it affect the luminal entry of eosinophils; (4) steroids permit elimination of eosinophils into airway lumen and slowly resolve established lung eosinophilia.
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