Anadromous Arctic charr
Salvelinus alpinus
is a cold-adapted salmonid that is vulnerable to climate warming and anthropogenic activities including salmon farming, hydropower regulation, and ...pollution, which poses a multiple-stressor scenario that influences or threatens populations. We studied the horizontal and vertical behaviour of Arctic charr tagged with acoustic transmitters (n = 45, mean fish length: 22 cm) in a pristine, subarctic marine area to provide insights into the behaviour of first-time migrants. Tagged fish spent up to 78 d at sea, with high marine survival (82% returned to their native watercourse). While at sea, they utilized mostly near-shore areas, up to 45 km away from their native river. Arctic charr showed large variation in migration distance (mean ± SD: 222 ± 174 km), and the migration distance increased with body size. Although the fish displayed a strong fidelity to surface waters (0-3 m), spatiotemporal variation in depth use was evident, with fish utilizing deeper depths during the day and in late July. These results represent baseline data on Arctic charr’s marine behaviour in a pristine fjord system and highlight the importance of near-shore surface water as feeding areas for first-time migrants. Furthermore, the observed dependency on coastal areas implies a vulnerability to increasing human-induced perturbations, on top of impacts by large-scale climate change in marine and freshwater habitats.
Diving behaviour of Atlantic salmon at sea Hedger, Richard D.; Rikardsen, Audun H.; Strøm, John F. ...
Marine ecology. Progress series (Halstenbek),
07/2017, Letnik:
574
Journal Article
Recenzirano
Odprti dostop
The diving behaviour of adult Atlantic salmon Salmo salar L. post-spawners in the Norwegian and Barents Seas was monitored with pop-up satellite archival tags (PSATs) and data storage tags (DSTs). ...Salmon from the 3 studied populations showed similar depth use patterns: tagged specimens spent most of their time near the surface (mean of 82% of the time at depths <10 m), with occasional short deep dives (>200 m depth, median time = 2.31 h; range = 0.18 to 22.5 h), the deepest recorded being 707 m. Increased use of greater depths occurred during daytime than night-time in the months between polar day and polar night (August to October). Diel change in depth use around the time of polar night (November to January) was weakest for the population (from the River Alta) that migrated furthest north. Diving was more frequent and shallower when the mixed layer was near the surface during the months of June to October. There was an increase in diving depth (>200 m) when the mixed layer extended to ∼200 or 300 m in winter and spring (December to April). Deep diving consisted of ‘U’ shaped dives, possibly indicative of foraging. We hypothesise that seasonal light conditions, dependent on geographical location, affect Atlantic salmon diving, and that changes in diving depth may be due to seasonal differences in prey aggregation.
Understanding spatiotemporal variation in vital rates and population growth rates is a central aim of population ecology, and is critical to conservation of migratory species where different ...populations may spend the non-breeding season in sometimes widely separated areas. However, estimating those parameters and identifying the underlying drivers of variation for species migrating to remote areas is challenging. The thick-billed murre
Uria lomvia
is a colonial seabird with a pan-Arctic distribution. Previous studies have documented large-scale spatial variation in population growth in the species’ Atlantic range, with eastern populations declining and western populations being stable, and suggested that this variation was linked to conditions in the wintering areas. We analyse variation in breeding success and adult survival from colonies throughout the Atlantic range, construct region-specific stochastic population models, and compare model predictions to observed colony growth rates. Breeding success was uniformly high in Greenland and Iceland, lower and more variable in Spitsbergen, Bjørnøya and Hudson Bay, and low at Jan Mayen. Adult survival was average or high in all colonies during the 2010s. Observed colony growth rates were lower than modelled growth rates for most populations. This suggests that pre-breeding survival or breeding propensity must have been lower than assumed in many of these populations. Low pre-breeding survival could be linked to poor feeding conditions in fall and winter, possibly influenced by large-scale oceanographic variation. Our results support the idea that seabird populations not subject to breeder mortality due to anthropogenic causes are regulated mainly through variation in pre-breeding survival.
Microscopic colitis (MC) is an inflammatory bowel disease and a common cause of chronic diarrhea. Appendectomy has been suggested to have immunomodulating effects in the colon, influencing the risk ...of gastrointestinal disease. The relationship between appendectomy and MC has only been sparsely studied.
This was a case-control study based on the nationwide ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) cohort, consisting of histopathological examinations in Sweden, linked to national registers. Patients with MC were matched to population controls by age, sex, calendar year of biopsy, and county of residence. Data on antecedent appendectomy and comorbidities were retrieved from the Patient Register. Unconditional logistic regression models were conducted presenting odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for country of birth and matching factors. Further subanalyses were made based on MC subtypes (lymphocytic colitis and collagenous colitis), follow-up time postappendectomy and severity of appendicitis.
The study included 14,520 cases of MC and 69,491 controls, among these 7.6% (n = 1103) and 5.1% (n = 3510), respectively, had a previous appendectomy ≥1 year prior to MC or matching date. Patients with a previous appendectomy had an increased risk of MC in total (OR, 1.50; 95% CI, 1.40–1.61) and per the collagenous colitis subtype (OR, 1.67; 95% CI, 1.48–1.88) or lymphocytic colitis subtype (OR, 1.42; 95% CI, 1.30–1.55). The risk remained elevated throughout follow-up, and the highest risk was observed in noncomplicated appendicitis.
This nationwide case-control study found a modestly increased risk of developing MC following appendectomy.
Study question What is the mortality in offspring of mothers who had influenza A(H1N1)pdm09 vaccination during pregnancy?Methods This was a prospective population based cohort study in seven ...healthcare regions in Sweden based on vaccinations taking place between 2 October 2009 and 26 November 2010. H1N1 vaccination data were linked with pregnancy and birth characteristics and offspring mortality data in 275 500 births (of which 1203 were stillbirths) from 137 886 mothers. Of these offspring, 41 183 had been exposed to vaccination with Pandemrix, a monovalent AS03 adjuvanted H1N1 influenza vaccine, during fetal life. A primary comparison group consisted of pregnancies of women who were not vaccinated during the same calendar period. In a second comparison, non-exposed siblings of infants prenatally exposed to vaccination were used as controls. Cox regression was used to estimate hazard ratios for stillbirth, early neonatal mortality (days 0-6 after birth), and subsequent mortality (beginning on day 7) in vaccinated versus non-vaccinated women, adjusting for mother’s age at delivery, body mass index, parity, smoking, country of birth, and disposable income and for sex of offspring.Study answer and limitations The results of this study suggest that AS03 adjuvanted H1N1 vaccination during pregnancy does not affect the risk of stillbirth, early neonatal death, or later mortality in the offspring. During follow-up, 1172 stillbirths, 380 early neonatal deaths, and 706 deaths thereafter occurred. Compared with general population controls, this corresponded to adjusted hazard ratios of 0.83 (95% confidence interval 0.65 to 1.04) for stillbirth, 0.71 (0.44 to 1.14) for early neonatal death, and 0.97 (0.69 to 1.36) for later death. When siblings were used as controls, adjusted hazard ratios were 0.88 (0.59 to 1.30) for stillbirth, 0.82 (0.46 to 1.49) for early neonatal death, and 0.78 (0.52 to 1.19) for later death. Limitations of the study include lack of data on miscarriage before gestational week 22, inability to ascertain which mothers had pandemic flu during pregnancy, and lack of data on factors influencing the decision to vaccinate during pregnancy.What this study adds H1N1 vaccination during pregnancy is not associated with adverse fetal outcome or offspring mortality, including when familial factors are taken into account.Funding, competing interests, data sharing This project was supported by grants from the Swedish Research Council and the Swedish Council for Working Life and Social Research. NF was employed at the Swedish Medical Product Agency at the time of the study.
Here we present a preclinical model to assess drug–drug interactions due to inhibition of glucuronidation. Treatment with the antiepileptics phenobarbital (PB) or phenytoin (PH) has been associated ...with increased incidence of acetaminophen (APAP) hepatotoxicity in patients. In human hepatocytes, we found that the toxicity of APAP (5 mM) was increased by simultaneous treatment with phenobarbital (2 mM) or phenytoin (0.2 mM). In contrast, pretreatment with PB for 48 h prior to APAP treatment did not increase APAP toxicity unless both drugs were present simultaneously. Cells treated with APAP in combination with PB or PH experienced decreases in protein synthesis as early as 1 h, ultrastructural changes by 24 h, and release of liver enzymes by 48 h. Toxicity correlated with inhibition of APAP glucuronidation. PB or PH also inhibited APAP glucuronidation in rat and human liver microsomes and expressed human UGT1A6, 1A9, and 2B15. As with intact hepatocytes, PB and PH were neither hydroxylated nor glucuronidated, suggesting the direct inhibition of UGTs. Our findings suggest that, in multiple drug therapy, an inhibitory complex between UGT and one of the drugs can lead to decreased glucuronidation and increased systemic exposure and toxicity of a coadministered drug.
Earlier studies reporting varying risk estimates for congenital malformation in offspring of mothers undergoing vaccination against H1N1 influenza during pregnancy did not consider the potential role ...of confounding by familial (genetic and shared environmental) factors.
To evaluate an association between maternal H1N1 vaccination during pregnancy and offspring malformation, with familial factors taken into account.
Population-based prospective study.
Sweden.
Liveborn offspring born between 1 October 2009 and 1 October 2011 to mothers receiving monovalent AS03-adjuvanted H1N1 influenza vaccine (Pandemrix GlaxoSmithKline) during pregnancy. A total of 40 983 offspring were prenatally exposed to the vaccine, 14 385 were exposed within the first trimester (14 weeks), and 7502 were exposed during the first 8 weeks of pregnancy. Exposed offspring were compared with 197 588 unexposed offspring. Corresponding risks in exposed versus unexposed siblings were also estimated.
Congenital malformation, with subanalyses for congenital heart disease, oral cleft, and limb deficiency.
Congenital malformation was observed in 2037 (4.97%) exposed offspring and 9443 (4.78%) unexposed offspring. Adjusted risk for congenital malformation was 4.98% in exposed offspring versus 4.96% in unexposed offspring (risk difference, 0.02% 95% CI, -0.26% to 0.30%). The corresponding risk differences were 0.16% (CI, -0.23% to 0.56%) for vaccination during the first trimester and 0.10% (CI, -0.41% to 0.62%) for vaccination in the first 8 weeks. Using siblings as comparators yielded no statistically significant risk differences.
The study was based on live births, and the possibility that data on miscarriage or induced abortion could have influenced the findings cannot be ruled out. Study power was limited in analyses of specific malformations.
When intrafamilial factors were taken into consideration, H1N1 vaccination during pregnancy did not seem to be linked to overall congenital malformation in offspring, although risk increases for specific malformations could not be ruled out completely.
Swedish Research Council and Swedish Council for Working Life and Social Research.
The discovery of afterglows associated with γ-ray bursts at X-ray, optical and radio wavelengths and
the measurement of the redshifts of some of these events, has established that γ-ray bursts lie at ...extreme distances,
making them the most powerful photon-emitters known in the Universe. Here
we report the discovery of transient optical emission in the error box of
the γ-ray burst GRB980425, the light curve of which was very different
from that of previous optical afterglows associated with γ-ray bursts.
The optical transient is located in a spiral arm of the galaxy ESO184-G82,
which has a redshift velocity of only 2,550 km s−1
(ref. 6). Its optical spectrum and location
indicate that it is a very luminous supernova, which has been
identified as SN1998bw. If this supernova and GRB980425 are indeed associated,
the energy radiated in γ-rays is at least four orders of magnitude less
than in other γ-ray bursts, although its appearance was otherwise unremarkable:
this indicates that very different mechanisms can give rise to γ-ray
bursts. But independent of this association, the supernova is itself unusual,
exhibiting an unusual light curve at radio wavelengths that requires that
the gas emitting the radio photons be expanding relativistically,.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Inhibition of canalicular bile acid efflux by medications is associated with clinical liver toxicity, sometimes in the absence of major liver effects in experimental species. To predict the ...hepatotoxic potential of compounds in vitro and in vivo, we investigated the effect of clinical cholestatic agents on 3Htaurocholic acid transport in regular and collagen-sandwich cultured human hepatocytes. Hepatocytes established a well-developed canalicular network with bile acid accumulating in the canalicular lumen within 15 min of addition to cells. Removing Ca2+ and Mg2+ from the incubation buffer destroyed canalicular junctions, resulting in bile acid efflux into the incubation buffer. Canalicular transport was calculated based on the difference between the amount of bile acid effluxed into the Ca/Mg2+-free and regular buffers with linear efflux up to 10 min. Hepatocytes cultured in the nonsandwich configuration also transported taurocholic acid, but at 50% the rate in sandwiched cultures. Cyclosporin A, bosentan, CI-1034, glyburide, erythromycin estolate, and troleandomycin inhibited efflux in a concentration-dependent manner. In contrast, new generation macrolide antibiotics with lower incidence of clinical hepatotoxicity were much less potent inhibitors of efflux. An in vivo study was conducted whereby glyburide or CI-1034, administered iv to male rats, produced a 2.4-fold increase in rat total serum bile acids. A synergistic 6.8-fold increase in serum total bile acids was found when both drugs were delivered together. These results provide methods to evaluate inhibitory effects of potentially cholestatic compounds on bile-acid transport, and to rank compounds according to their hepatotoxic potential.
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