| 1. |
- Imamura, Teruhiko, et al.
(författare)
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A case with recovery of response to tolvaptan associated with remission of acute kidney injury and increased urine osmolality
- 2013
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Ingår i: International Heart Journal. - : International Heart Journal Association. - 1349-2365 .- 1349-3299. ; 54:2, s. 115-118
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Tidskriftsartikel (refereegranskat)abstract
- Tolvaptan (TLV), a vasopressin type 2 receptor antagonist, has been demonstrated to be effective in patients with decompensated heart failure (HF) refractory to incremental doses of diuretics, but the responsiveness has not always been predictable. We have recently proposed that urine osmolality (U-OSM) is a valuable parameter for the prediction of responses to TLV, because U-OSM reflects the activity of the collecting ducts, where TLV plays its unique role. Acute kidney injury (AKI) is often associated with severe tubular dysfunction, including the collecting ducts, and in such cases a response to TLV may not be expected. We here experienced a patient with HF and AKI in whom TLV was not effective during AKI. We also observed recovery of responsiveness to TLV along with remission of AKI as well as increased U-OSM later on. We believe that this is the first report on the reversibility of the TLV response in relation to U-OSM.
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| 2. |
- Takahashi, Daisuke, et al.
(författare)
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Abrupt community transitions and cyclic evolutionary dynamics in complex food webs
- 2013
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Ingår i: Journal of Theoretical Biology. - : Academia Press. - 0022-5193 .- 1095-8541. ; 337, s. 181-189
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the emergence and maintenance of biodiversity ranks among the most fundamental challenges in evolutionary ecology. While processes of community assembly have frequently been analyzed from an ecological perspective, their evolutionary dimensions have so far received less attention. To elucidate the eco-evolutionary processes underlying the long-term build-up and potential collapse of community diversity, here we develop and examine an individual-based model describing coevolutionary dynamics driven by trophic interactions and interference competition, of a pair of quantitative traits determining predator and prey niches. Our results demonstrate the (1) emergence of communities with multiple trophic levels, shown here for the first time for stochastic models with linear functional responses, and (2) intermittent and cyclic evolutionary transitions between two alternative community states. In particular, our results indicate that the interplay of ecological and evolutionary dynamics often results in extinction cascades that remove the entire trophic level of consumers from a community. Finally, we show the (3) robustness of our results under variations of model assumptions, underscoring that processes of consumer collapse and subsequent rebound could be important elements of understanding biodiversity dynamics in natural communities.
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