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- Gustafsson, Lars, et al.
(författare)
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Infectious disease, reproductive effort and the cost of reproduction in birds
- 1994
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Ingår i: Philosophical transactions of the Royal Society of London: Series B. ; :346, s. 1655-1658
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Reproductive effort can have profound effects on subsequent performance. Field experiments on the collared flycatcher (Ficedula albicollis) have demonstrated a number of trade-offs between life-history traits at different ages. The mechanism by which reproductive effort is mediated into future reproductive performance remains obscure. Anti-parasite adaptations such as cell-mediated immunity may probably also be costly. Hence the possibility exists of a trade-off between reproductive effort and the ability to resist parasitic infection. Serological tests on unmanipulated collared flycatchers show that pre-breeding nutritional status correlates positively with reproductive success and negatively with susceptibility to parasitism (viruses, bacteria and protozoan parasites). Both immune response and several indicators of infectious disease correlate negatively with reproductive success. Similar relations are found between secondary sexual characters and infection parameters. For brood-size-manipulated birds there was a significant interaction between experimentally increased reproductive effort and parasitic infection rate with regard to both current and future fecundity. It seems possible that the interaction between parasitic infection, nutrition and reproductive effort can be an important mechanism in the ultimate shaping of life-history variation in avian populations.
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| 2. |
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| 3. |
- Wide-Swensson, Dag, et al.
(författare)
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Effects of isradipine, a new calcium antagonist, on maternal cardiovascular system and uterine activity in labour
- 1990
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Ingår i: British Journal of Obstetrics and Gynaecology. - : Wiley. - 1365-215X .- 1470-0328 .- 1471-0528. ; 97:10, s. 945-949
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Tidskriftsartikel (refereegranskat)abstract
- The effects of isradipine (a new calcium antagonist of the dihydropyridine type) on maternal blood pressure and heart rate, fetal heart rate, and uterine activity in labour were measured. Uterine activity was recorded by an intrauterine microtip transducer catheter connected to a fetal monitor. Isradipine was given as a slow injection in doses of 0.5 mg (10 women), 1 mg (11 women), and 1.5 mg (6 women). A reduction of systolic (6-16%) and diastolic (19-22%) blood pressure was seen, and concomitantly there was an increase in maternal (29-34%) and fetal (3-10%) heart rates. Reduction in uterine activity was not dose-related (maximum reduction 17%). Side effects (headache, palpitations) were minor and well tolerated. One women in the high-dose group had a shortlasting episode of hypotension. The results suggest that isradipine given as a bolus dose decreases blood pressure in pregnant women with little effects on uterine activity and fetal heart rate.
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