515 research outputs found
Long-term effect of yolk carotenoid levels on testis size in a precocial bird
This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this record.Conditions experienced during prenatal development can have long-lasting organizational effects on offspring. Maternal carotenoids deposited in the eggs of birds and other oviparous species play an important role during fast embryonic growth and chick development through their antioxidant properties. However, the long-term consequences of variation in maternal carotenoid transfer for the offspring have seldom been considered. Since plasma carotenoid levels at adulthood are known to influence testis size and yolk carotenoid levels influence the ability to extract carotenoids later in life, we hypothesized that maternally transmitted carotenoids might influence gonad size at adulthood. Here, we showed that male Japanese quail (Coturnix japonica) originating from a carotenoid-enriched egg had smaller testes than control individuals at adulthood. This result shows that yolk carotenoids have long-term organizational effects. In addition, given that carotenoid intake at sexual maturity increases sperm quality and that a decreased testis size is associated with a lower sperm production, we propose that carotenoid exposure during embryo development might influence a trade-off between ejaculate size and sperm quality.The study was supported by the Swiss National Science Foundation (PP00P3_128386 and PP00P3_157455) and the Fonds zur Förderung des akademischen Nachwuchses
Northward advection of Atlantic water in the eastern Nordic Seas over the last 3000 yr
Three marine sediment cores distributed along the
Norwegian (MD95-2011), Barents Sea (JM09-KA11-GC),
and Svalbard (HH11-134-BC) continental margins have been
investigated in order to reconstruct changes in the poleward
flow of Atlantic waters (AW) and in the nature of upper
surface water masses within the eastern Nordic Seas over
the last 3000 yr. These reconstructions are based on a limited
set of coccolith proxies: the abundance ratio between
Emiliania huxleyi and Coccolithus pelagicus, an index of Atlantic
vs. Polar/Arctic surface water masses; and Gephyrocapsa
muellerae, a drifted coccolith species from the temperate
North Atlantic, whose abundance changes are related
to variations in the strength of the North Atlantic Current.
The entire investigated area, from 66 to 77 N, was affected
by an overall increase in AWflow from 3000 cal yr BP
(before present) to the present. The long-term modulation
of westerliesâ strength and location, which are essentially
driven by the dominant mode of the North Atlantic Oscillation
(NAO), is thought to explain the observed dynamics of
poleward AW flow. The same mechanism also reconciles the
recorded opposite zonal shifts in the location of the Arctic
front between the area off western Norway and the western
Barents Seaâeastern Fram Strait region.
The Little Ice Age (LIA) was governed by deteriorating
conditions, with Arctic/Polar waters dominating in the surface
off western Svalbard and western Barents Sea, possibly
associated with both severe sea ice conditions and a strongly
reduced AW strength. A sudden short pulse of resumed high
WSC (West Spitsbergen Current) flow interrupted this cold
spell in eastern Fram Strait from 330 to 410 cal yr BP. Our
dataset not only confirms the high amplitude warming of
surface waters at the turn of the 19th century off western
Svalbard, it also shows that such a warming was primarily
induced by an excess flow of AW which stands as unprecedented
over the last 3000 yr
In ovo yolk carotenoid and testosterone levels interactively influence female transfer of yolk antioxidants to her eggs
This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this recordMothers can influence prenatal conditions by varying the amount of nutrients, hormones or antioxidants they provide to their developing young. Some of these substances even affect the transfer of these compounds in the next generation, but it is less clear how different maternally transmitted compounds interact with each other to shape reproductive resource allocation in their offspring. Here, we found that female Japanese quail that were exposed to high carotenoid levels during embryonic development transferred lower concentrations of yolk antioxidants to their own eggs later in life. This effect disappeared, when both testosterone and carotenoid concentrations were manipulated simultaneously, showing long-term and interactive effects of these maternally derived egg components on a femaleâs own egg composition. Given that exposure to high levels of testosterone during embryo development stimulates the production of reactive oxygen (ROS) and impairs antioxidant defenses, we propose that carotenoids act as in-ovo antioxidants in an oxidatively stressful environment (i.e. when levels of testosterone are high) but might have prooxidant properties in an environment where they are not used to counteract an increased production of ROS. In line with this hypothesis, we previously showed that prenatal exposure to increased concentrations of yolk carotenoids leads to a rise of oxidative damage at adulthood, but only when yolk testosterone concentrations were not experimentally increased as well. As a consequence, antioxidants in the body may be used to limit oxidative damage in females exposed to high levels of carotenoids during development (but not in females exposed to increased levels of both carotenoids and testosterone), resulting in lower amounts of antioxidants being available for deposition into eggs. Since prenatal antioxidant exposure is known to influence fitness-related traits, the effect detected in this study might have transgenerational consequences.The study was supported by the Swiss National Science Foundation (PP00P3_128386 and
PP00P3_157455) and the Fonds zur Förderung des akademischen Nachwuchses
Matrilineal inheritance of a key mediator of prenatal maternal effects
This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this record.Sex-linkage is predicted to evolve in response to sex-specific or sexually antagonistic selection. In line with this prediction, most sex-linked genes are associated with reproduction in the respective sex. In addition to traits directly involved in fertility and fecundity, mediators of maternal effects may be predisposed to evolve sex-linkage, because they indirectly affect female fitness through their effect on offspring phenotype. Here, we test for sex-linked inheritance of a key mediator of prenatal maternal effects in oviparous species, the transfer of maternally derived testosterone to the eggs. Consistent with maternal inheritance, we found that in Japanese quail (Coturnix japonica) granddaughters resemble their maternal (but not their paternal) grandmother in yolk testosterone deposition. This pattern of resemblance was not due to non-genetic priming effects of testosterone exposure during prenatal development, as an experimental manipulation of yolk testosterone levels did not affect the females' testosterone transfer to their own eggs later in life. Instead, W chromosome and/or mitochondrial variation may underlie the observed matrilineal inheritance pattern. Ultimately, the inheritance of mediators of maternal effects along the maternal line will allow for a fast and direct response to female-specific selection, thereby affecting the dynamics of evolutionary processes mediated by maternal effects.The study was financially supported by Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (PP00P3_128386 and PP00P3_157455) and Fonds zur Förderung des akademischen Nachwuchses (FAN)
Darwin, the devil, and the management of transmissible cancers
Modern conservation science frequently relies on genetic tools to manage imperiled populations threatened by processes such as habitat fragmentation and infectious diseases. Translocation of individuals to restore genetic diversity (genetic rescue) is increasingly used to manage vulnerable populations, but it can swamp local adaptations and lead to outbreeding depression. Thus, genetic management is context dependent and needs evaluation across multiple generations . Genomic studies can help evaluate the extent to which populations are locally adapted to assess the costs and benefits of translocations. Predicting the longâterm fitness effects of genetic interventions and their evolutionary consequences is a vital step in managing dwindling populations threatened by emerging infectious diseases
Treatment of chronic hepatitis C in patients unresponsive to interferon. Interest of re-treatment combining interferon induction therapy and ribavirin (a multicenter pilot study)
Aim
About 45% of patients with chronic hepatitis C are unresponsive to the present reference treatment combining pegelated interferon plus ribavirin; before pegylated interferon was available the non-response rate was around 60%. This open multicenter pilot study, initiated before pegylated interferon became available, was designed to evaluate, in patients unresponsive to interferon monotherapy, the rate of biological and virological response and side-effects of the ribivirin- alpha 2b interferon combination.
Methods
The combination protocol was ribavirin (1 to 1.2Â g/d) plus alpha 2b interferon at induction doses (9 MU/d the first week; 4.5Â MU/d the eleven following weeks; 3Â MU/2 days the 36 following weeks).
Results
Among the 27 included patients, 17 (63%) were viremia-negative (PCR) after 12Â weeks of treatment, 9 (33%) were complete responders (undetectable viremia and normal transaminases) at the end of treatment (48Â weeks) and of follow-up (72Â weeks). Patients with non-1, non-4 genotypes who derived full benefit from this therapeutic strategy (6/7 (86%) were complete responders: 4/5 with genotype 3 and 2/2 with genotype 5). Quality-of-life was impaired during treatment, especially during the first 12Â weeks of high-dose interferon therapy.
Conclusion
While waiting for new therapeutic possibilities, these good results suggest interferon induction at the beginning of treatment remains a valid option
Timeline cluster: a graphical tool to identify risk of bias in cluster randomised trials
Robust evidence of the effectiveness of interventions relating to policy, practice, and organisation of healthcare often comes from well conducted cluster randomised trials. Such trials are, however, prone to recruitment bias depending on whether participants are recruited before the randomisation of clusters and whether the recruiter is blinded to the allocation status. In most cases, participants and trial staff cannot be blinded to the intervention, which might lead to performance and detection bias. Unfortunately, cluster trial reports often do not provide a clear description of the timing of trial processes and blinding, and these aspects are not covered by current reporting tools. This article proposes a graphical tool depicting the time sequence of steps and blinding status in cluster randomised trials. The tool might be helpful at both the protocol and the report writing stages to clarify the process and to help identify potential bias in cluster randomised trials
Cluster over individual randomization: are study design choices appropriately justified? Review of a random sample of trials
Taljaard, M., Goldstein, C. E., Giraudeau, B., Nicholls, S. G., Carroll, K., Hey, S. P., ⊠Weijer, C. (2020). Cluster over individual randomization: are study design choices appropriately justified? Review of a random sample of trials. Clinical Trials. Copyright © The Author(s), 2020. DOI: https://doi.org/10.1177/174077451989679
The Gift of Future Time: Islamic Welfare and Entrepreneurship in 21st century Indonesia
The attainment of religiously informed and socially responsible wealth is a desire widespread in the metropolises of Java, Indonesia, especially amongst the pious middle classes. This article aims at an understanding of the emergence and effects of an early 21st century desire for pious entrepreneurial success, by focusing on the practices people consistently and regularly undertake in order to actualise this. It claims that the religiously informed desire for entrepreneurial success is permeated by a mode of temporality that privileges the future at the expense of the past and the present. This temporal orientation has important consequences for subject-making, as it forces the subjectivities created to take a distinctively asymptotic form, resulting in the production of self-differing subjects; that is, subjects in which past, present and future actualisations lack coincidence and complete convergence
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