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- Frossard, Aline, et al.
(författare)
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Long- and short-term effects of mercury pollution on the soil microbiome
- 2018
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717. ; 120, s. 191-199
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Tidskriftsartikel (refereegranskat)abstract
- Despite the toxicity of mercury (Hg) for organisms in the environment, little is known on its impact on the soil microbiome, especially its chronic effect. Here, we assessed the effects of a long-term contamination of Hg in soils on the bacterial and fungal communities along a gradient of contamination from no to high contamination. Short-term reactions (30 days) of the microbial communities in these soils having different levels of historic Hg contamination were further evaluated in microcosm experiments where soils were either spiked with dissolved HgCl2 or not. Results show a clear impact of a long-term Hg contamination on both bacterial and fungal community structures and diversity but only a weak effect was observed on their activities (basal respiration and growth rates). No short-term effects of Hg were observed on the microbial community structures and activities. Taxa from the Chthoniobacteraceae (bacteria) and Trichosporon sp. (fungi) were associated with high Hg contaminated soils, implying they possess capabilities to tolerate Hg in soils. Abundance of mercury reductase (merA) gene copies increased with higher Hg concentrations in soils both during short and long-term exposure to Hg pointing to potential mechanisms within microbial cells to tolerate higher amounts of Hg in soils.
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| 2. |
- Sitbon, Olivier, et al.
(författare)
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Selexipag for the Treatment of Pulmonary Arterial Hypertension
- 2015
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 373:26
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In a phase 2 trial, selexipag, an oral selective IP prostacyclin-receptor agonist, was shown to be beneficial in the treatment of pulmonary arterial hypertension.METHODS: In this event-driven, phase 3, randomized, double-blind, placebo-controlled trial, we randomly assigned 1156 patients with pulmonary arterial hypertension to receive placebo or selexipag in individualized doses (maximum dose, 1600 μg twice daily). Patients were eligible for enrollment if they were not receiving treatment for pulmonary arterial hypertension or if they were receiving a stable dose of an endothelin-receptor antagonist, a phosphodiesterase type 5 inhibitor, or both. The primary end point was a composite of death from any cause or a complication related to pulmonary arterial hypertension up to the end of the treatment period (defined for each patient as 7 days after the date of the last intake of selexipag or placebo).RESULTS: A primary end-point event occurred in 397 patients--41.6% of those in the placebo group and 27.0% of those in the selexipag group (hazard ratio in the selexipag group as compared with the placebo group, 0.60; 99% confidence interval, 0.46 to 0.78; P<0.001). Disease progression and hospitalization accounted for 81.9% of the events. The effect of selexipag with respect to the primary end point was similar in the subgroup of patients who were not receiving treatment for the disease at baseline and in the subgroup of patients who were already receiving treatment at baseline (including those who were receiving a combination of two therapies). By the end of the study, 105 patients in the placebo group and 100 patients in the selexipag group had died from any cause. Overall, 7.1% of patients in the placebo group and 14.3% of patients in the selexipag group discontinued their assigned regimen prematurely because of adverse events. The most common adverse events in the selexipag group were consistent with the known side effects of prostacyclin, including headache, diarrhea, nausea, and jaw pain.CONCLUSIONS: Among patients with pulmonary arterial hypertension, the risk of the primary composite end point of death or a complication related to pulmonary arterial hypertension was significantly lower with selexipag than with placebo. There was no significant difference in mortality between the two study groups. (Funded by Actelion Pharmaceuticals; GRIPHON ClinicalTrials.gov number, NCT01106014.).
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