39 research outputs found

    Climate change, phenological shifts, eco-evolutionary responses and population viability: toward a unifying predictive approach

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    The debate on emission targets of greenhouse gasses designed to limit global climate change has to take into account the ecological consequences. One of the clearest ecological consequences is shifts in phenology. Linking these shifts to changes in population viability under various greenhouse gasses emission scenarios requires a unifying framework. We propose a box-in-a-box modeling approach that couples population models to phenological change. This approach unifies population modeling with both ecological responses to climate change as well as evolutionary processes. We advocate a mechanistic embedded correlative approach, where the link from genes to population is established using a periodic matrix population model. This periodic model has several major advantages: (1) it can include complex seasonal behaviors allowing an easy link with phenological shifts; (2) it provides the structure of the population at each phase, including the distribution of genotypes and phenotypes, allowing a link with evolutionary processes; and (3) it can incorporate the effect of climate at different time periods. We believe that the way climatologists have approached the problem, using atmosphere–ocean coupled circulation models in which components are gradually included and linked to each other, can provide a valuable example to ecologists. We hope that ecologists will take up this challenge and that our preliminary modeling framework will stimulate research toward a unifying predictive model of the ecological consequences of climate change

    Obesity: An overview on its current perspectives and treatment options

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    Obesity is a multi-factorial disorder, which is often associated with many other significant diseases such as diabetes, hypertension and other cardiovascular diseases, osteoarthritis and certain cancers. The management of obesity will therefore require a comprehensive range of strategies focussing on those with existing weight problems and also on those at high risk of developing obesity. Hence, prevention of obesity during childhood should be considered a priority, as there is a risk of persistence to adulthood. This article highlights various preventive aspects and treatment procedures of obesity with special emphasis on the latest research manifolds

    Dispersion explains declines

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    Amylinergic control of ingestive behavior

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    Amylin controls nutrient fluxes by reducing food intake, slowing gastric emptying and reducing postprandial glucagon secretion via a direct effect on the area postrema (AP). In the AP, amylin seems to modulate the anorectic signal elicited by cholecystokinin (CCK). Amylin’s excitatory action on AP neurons and its anorectic effect may depend on diet composition because rats fed protein as exclusive energy source showed a blunted response to amylin. In addition to a role in satiation (“episodic signal”), recent studies suggest that amylin may also play a role as an adiposity (“tonic”) signal. Similar to leptin or insulin, an elevated brain level of amylin resulted in lower body weight gain than in controls. This may also in part be due to an increase in energy expenditure. Overall, amylin may be an interesting target as a body weight lowering drug. Recent studies provided evidence that amylin, especially when combined with insulin, leptin or PYY has long-term effects on food intake and body weight in humans

    SARC006: Phase II Trial of Chemotherapy in Sporadic and Neurofibromatosis Type 1 Associated Chemotherapy-Naive Malignant Peripheral Nerve Sheath Tumors.

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    Background:Worse chemotherapy response for neurofibromatosis type 1- (NF1-) associated compared to sporadic malignant peripheral nerve sheath tumors (MPNST) has been reported. Methods:We evaluated the objective response (OR) rate of patients with AJCC Stage III/IV chemotherapy-naive NF1 MPNST versus sporadic MPNST after 4 cycles of neoadjuvant chemotherapy, 2 cycles of ifosfamide/doxorubicin, and 2 cycles of ifosfamide/etoposide. A Simon optimal two-stage design was used (target response rate 40%). Results:34 NF1 (median age 33 years) and 14 sporadic (median age 40 years) MPNST patients enrolled. Five of 28 (17.9%) evaluable NF1 MPNST patients had a partial response (PR), as did 4 of 9 (44.4%) patients with sporadic MPNST. Stable disease (SD) was achieved in 22 NF1 and 4 sporadic MPNST patients. In both strata, results in the initial stages met criteria for expansion of enrollment. Only 1 additional PR was observed in the expanded NF1 stratum. Enrollment was slower than expected and the trial closed before full accrual. Conclusions:This trial was not powered to detect differences in response rates between NF1 and sporadic MPNST. While the OR rate was lower in NF1 compared to sporadic MPNST, qualitative responses were similar, and disease stabilization was achieved in most patients

    Classification and controversies in pathology of ependymomas.

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    PURPOSE: Bailey and Cushing established ependymoma as a brain tumour entity in the first brain tumour classification (1926). Diagnosis of ependymomas is not subject to controversy as long as other tumours presenting ependymoma-like features have been ruled out. Grading conversely is a source of debate. Description of histological features establishing diagnosis and grading of ependymomas may help to better understand this controversy. METHODS: Literature has been reviewed using PubMed with the following key words: ependymoma, +/- prognosis, +/- biomaker, +/- grading, +/- immunohistochemistry, +/- proliferative index. RESULTS: Grading controversy arises from elusive WHO features and individual characteristics of ependymomas including tumour location, tumour pattern/variant and variable expression of biomarkers. CONCLUSION: There is a need for a grading scheme with a proven general ability to dissociate grades, and to predict individual clinical evolution. Only then will stratified and targeted therapeutics for ependymal tumours be possible

    Long-distance migratory birds threatened by multiple independent risks from global change

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    Many species migrate long distances annually between their breeding and wintering areas1. Although global change affects both ranges, impact assessments have generally focused on breeding ranges and ignored how environmental changes influence migrants across geographical regions and the annual cycle2,3. Using range maps and species distribution models, we quantified the risk of summer and winter range loss and migration distance increase from future climate and land cover changes on long-distance migratory birds of the Holarctic (n = 715). Risk estimates are largely independent of each other and magnitudes vary geographically. If seasonal range losses and increased migration distances are not considered, we strongly underestimate the number of threatened species by 18–49% and the overall magnitude of risk for 17–50% species. Many of the analysed species that face multiple global change risks are not listed by International Union for Conservation of Nature as threatened or near threatened. To neglect seasonal migration in impact assessments could thus seriously misguide species’ conservation
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