Ethylene and flooding resistance : I. An ecophysiological approach with Rumex as a model

Contains fulltext : 15908.pdf (publisher's version ) (Open Access

De rol van de 18-FDG PET-scan bij de diagnose dementie

De CBO-richtlijn dementie uit 2005 acht de Positron Emissie Tomografie (PET) -scan niet geschikt als eerste keus voor beeldvorming met het oog op de extra belasting voor de patiënt, de beperkte beschikbaarheid van het onderzoek en het feit dat hiermee chirurgisch behandelbare oorzaken niet zijn uit te sluiten. Differentiële diagnose tussen Ziekte van Alzheimer (ZvA) en andere oorzaken van dementie is belangrijk omdat het natuurlijke beloop en de behandeling verschillen. Wij presenteren drie patiënten van 62, 68 en 71 jaar die verwezen werden naar de geheugenpolikliniek vanwege de verdenking van een dementiesyndroom. Na afronding van de gebruikelijke analyse inclusief MRI van het cerebrum bleef de etiologie van de dementie bij deze patiënten onduidelijk. Bij deze patiënten werd de analyse uitgebreid met een 18 FDG PET-scan van de hersenen, waarna de etiologie van de dementie kon worden vastgesteld. In geval van ontbreken van cerebrale atrofie bij patiënten met een hoge klinische verdenking op ZvA en Frontotemporaaldementie (FTD) heeft onderzoek met 18 FDG PETscan een toegevoegde waarde. Ons inziens heeft de 18 FDG PET-scan van de hersenen in de geheugenpoliklinieken een plaats in de analyse van een dementiesyndroom met onduidelijke etiologie

Plant hormones regulate fast shoot elongation under water: From genes to communities

Contains fulltext : 57981.pdf (publisher's version ) (Open Access)Flooding affects the abundance and distribution of plant species worldwide. Many plants are damaged or even killed by flooding events, due to the associated oxygen deprivation in cells. Stimulated shoot elongation is an important adaptive mode that can restore contact of leaves with the atmosphere above the water surface. This strongly improves inward diffusion of oxygen and the rate of photosynthesis. Fast elongation of submerged petioles of the model plant Rumex palustris involves the integrated action of the plant hormones ethylene, auxin, gibberellin, and abscisic acid. The closely related Rumex acetosa is unable to switch on petiole elongation when submerged. In a comparative study of these two Rumex species, we found that the response to the gaseous phytohormone ethylene, which accumulates in plant tissues during submergence, explains their contrasting elongation behavior. In order to study the importance of this shoot elongation response in the distributional patterns of plants in natural floodplains, we quantified the ethylene-induced elongation response of 22 plant species occurring in the Rhine River floodplain. These results were compared with the results of a multivariate analysis based on 84 vegetation surveys performed in the same area. The species compositions of the surveys were grouped along two environmental gradients: flooding duration and soil dehydration after the floodwater subsided. If we superimpose the ethylene-induced elongation capacity on these vegetation data, it becomes clear that the capacity to elongate upon exposure to ethylene positively correlates with flooding duration and negatively with soil dehydration. Based on this analysis, we conclude that the capacity to elongate is an important selective trait in field distribution patterns of plants in flood-prone environments. Fast shoot elongation under water seems to be a favorable trait only in environments with shallow and prolonged flooding events, while costs associated with this response prevent its expression in sites with deep floods, sites with floods short in duration, or in sites in which flood water recedes rapidly. The approach outlined in this paper may be more widely applicable in ecological studies that aim to understand the functional relationship between plant traits and species distributions along environmental gradients

An alternative diagnostic strategy with lower radiatioin risk in young women with suspected pulmonary embolism

Background: Since younger women have an increased risk of cancer following radiation exposure with CT scanning, they might benefit from an alternative diagnostic strategy for suspected pulmonary embolism (PE).Methods: We investigated the safety and efficiency of a diagnostic strategy consisting of clinical probability, D-dimer testing, chest X-ray and perfusion-scintigraphy in women aged <50 years with suspected PE, in order to reduce the number of CT scans. This strategy was retrospectively analyzed in two cohorts of consecutive patients with suspected PE, in which perfusion scans and chest X- rays were combined (X/Q-scan). X/Q-scans were re-evaluated in the second cohort. We calculated the predictive accuracy and the proportion of women in whom CT could be avoided. Results: A total of 236 women <50 years with suspected PE were included. The prevalence of PE was 20% and 19% for the first and second cohort, respectively. PE was excluded in 51% (81/159) and 32% (25/77) based on an unlikely Wells score combined with a normal D-dimer test. In the remaining women in the first cohort, 44% (95%CI, 33-55%) had a normal X/Q-scan; 40% (CI 30-51%) had a non-high X/Q-scan and 14% (CI 8-24%) a high-probability X/Q-scan. In the second cohort, these percentages were 58% (44-70%), 17% (9-30%) and 25% (CI 15-38%), respectively. The positive predictive value of a high probability X/Q-scan was high in both cohorts: 82% (95%CI, 52-95%) and 100% (CI 77-100%), respectively. CT could theoretically be avoided in 60% and 83% (CI 70-91%) of women. Conclusion: A diagnostic strategy consisting of clinical decision rule, D-dimer testing, perfusion scintigraphy and chest X-ray appears to be promising to reliably exclude or diagnose PE in young women, without the need for CT-scanning. Further prospective evaluation in a larger population of young women is warranted

Maternal allopurinol administration during suspected fetal hypoxia: a novel neuroprotective intervention? A multicentre randomised placebo controlled trial

Developmen

Predictive Performance of Cardiovascular Disease Risk Prediction Algorithms in People Living With HIV

Immunogenetics and cellular immunology of bacterial infectious disease

Progression of liver fibrosis following acute hepatitis C virus infection in HIV-positive MSM

Molecular basis of virus replication, viral pathogenesis and antiviral strategie