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  • 1
    Language: English
    In: Environmental monitoring and assessment, January 2014, Vol.186(1), pp.257-75
    Description: The consistency of visual assessment of tree defoliation, which represents the most widely used indicator for tree condition, has frequently been in the focus of scientific criticism. Thus, the objective of the present study was to examine the consistency of the defoliation data from the annual national training courses for the forest condition survey in Germany from 1992 to 2012. Defoliation assessments were carried out in stands of beech (Fagus sylvatica), oak (Quercus robur and Quercus petraea), Norway spruce (Picea abies), and pine (Pinus sylvestris). Among the observer teams, the absolute deviation from the observer mean of all years was ±4.4 % defoliation and the standard deviation of defoliation was ±5.5 %. On average, 94 % of the assessments were located within the ±10 % interval of deviation from the mean. Tree species-specific differences did not occur when all years were considered. A trend towards increasing consistency was observed from 1992 to 2012, in particular for oak and spruce. The deviation of defoliation assessments depended non-linearly on the level of defoliation with highest deviations at intermediate defoliations. In spite of high correlations and agreements among observers, systematic errors were determined in nearly every year. However, within-observer variances were higher than between-observer variances. The present study applied a three-way evaluation approach for the assessment of consistency and demonstrated that the visual defoliation assessment at the national training courses in general produced consistent data within Germany from 1992 to 2012.
    Keywords: Environmental Monitoring -- Methods ; Forestry -- Education ; Trees -- Physiology
    ISSN: 01676369
    E-ISSN: 1573-2959
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  • 2
    In: Global Change Biology, August 2014, Vol.20(8), pp.2644-2662
    Description: The ational orest oil nventory () provides the reenhouse as eporting in ermany with a quantitative assessment of organic carbon () stocks and changes in forest soils. Carbon stocks of the organic layer and the mineral topsoil (30 cm) were estimated on the basis of ca. 1.800 plots sampled from 1987 to 1992 and resampled from 2006 to 2008 on a nationwide grid of 8 × 8 km. Organic layer stock estimates were attributed to surveyed forest stands and land cover data. Mineral soil stock estimates were linked with the distribution of dominant soil types according to the oil ap of ermany (1 : 1 000 000) and subsequently related to the forest area. It appears that the pool of the organic layer was largely depending on tree species and parent material, whereas the pool of the mineral soil varied among soil groups. We identified the organic layer pool as stable although was significantly sequestered under coniferous forest at lowland sites. The mineral soils, however, sequestered 0.41 Mg C ha yr. Carbon pool changes were supposed to depend on stand age and forest transformation as well as an enhanced biomass input. Carbon stock changes were clearly attributed to parent material and soil groups as sandy soils sequestered higher amounts of , whereas clayey and calcareous soils showed small gains and in some cases even losses of soil . We further showed that the largest part of the overall sample variance was not explained by fine‐earth stock variances, rather by the concentrations variance. The applied uncertainty analyses in this study link the variability of strata with measurement errors. In accordance to other studies for entral urope, the results showed that the applied method enabled a reliable nationwide quantification of the soil pool development for a certain period.
    Keywords: C/N Ratio ; Carbon Sequestration ; Carbon Stocks ; Forest Stand Type ; Mineral Soil ; Nation Forest Soil Inventory ; Organic Layer ; Soil Groups ; Soil Organic Matter ; Soil Survey ; Tree Species ; Uncertainties
    ISSN: 1354-1013
    E-ISSN: 1365-2486
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  • 3
    Language: English
    In: Science of the Total Environment, 10 January 2019, Vol.647, pp.1573-1585
    Description: Forest soils represent a large carbon pool and already small changes in this pool may have an important effect on the global carbon cycle. To predict the future development of the soil organic carbon (SOC) pool, well-validated models are needed. We applied the litter and soil carbon model Yasso15 to 1838 plots of the German national forest soil inventory (NFSI) for the period between 1985 and 2014 to enables a direct comparison to the NFSI measurements. In addition, to provide data for the German Greenhouse Gas Inventory, we simulated the development of SOC with Yasso15 applying a climate projection based on the RCP8.5 scenario. The initial model-calculated SOC stocks were adjusted to the measured ones in the NFSI. On average, there were no significant differences between the simulated SOC changes (0.25 ± 0.10 Mg C ha  a ) and the NFSI data (0.39 ± 0.11 Mg C ha  a ). Comparing regional soil-unit-specific aggregates of the SOC changes, the correlation between both methods was significant (r  = 0.49) although the NFSI values had a wider range and more negative values. In the majority of forest types, representing 75% of plots, both methods produced similar estimates of the SOC balance. Opposite trends were found in mountainous coniferous forests on acidic soils. These soils had lost carbon according to the NFSI (−0.89 ± 0.30 Mg C ha  a ) whereas they had gained it according to Yasso15 (0.21 ± 0.10 Mg C ha  a ). In oligotrophic pine forests, the NFSI indicated high SOC gains (1.36 ± 0.17 Mg C ha  a ) and Yasso15 much smaller (0.29 ± 0.10 Mg C ha  a ). According to our results, German forest soils are a large carbon sink. The application of the Yasso15 model supports the results of the NFSI. The sink strength differs between forest types possibly because of differences in organic matter stabilisation.
    Keywords: Soil Carbon Changes ; Soil Organic Carbon ; Climate ; Soil Inventory ; Yasso15 ; Litter and Soil Carbon Model ; Temperate Forests ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 4
    In: European Journal of Haematology, September 2016, Vol.97(3), pp.239-244
    Description: Byline: Nicole Degwert, Emily Latuske, Gabi Vohwinkel, Hauke Stamm, Marianne Klokow, Carsten Bokemeyer, Walter Fiedler, Jasmin Wellbrock Keywords: Acute myeloid leukaemia; hypoxia; drug resistance; deoxycytidine kinase; hypoxia-inducible factor 1 alpha Abstract Objectives Leukaemia initiating cells reside within specialised niches in the bone marrow where they undergo complex interactions with different stromal cell types. The bone marrow niche is characterised by a low oxygen content resulting in high expression of hypoxia-inducible factor 1 [alpha] in leukaemic cells conferring a negative prognosis to patients with acute myeloid leukaemia (AML). Methods and Results In the current study, we investigated the impact of hypoxic vs. normoxic conditions on the sensitivity of AML cell lines and primary AML blasts to cytarabine. AML cells cultured under 6% oxygen were significantly more resistant against cytarabine compared to cells cultured under normoxic conditions in proliferation and colony-formation assays. Interestingly upon cultivation under hypoxia, the expression of the cytarabine-activating enzyme deoxycytidine kinase was downregulated in all analysed AML cell lines and primary AML samples representing a possible mechanism for resistance to chemotherapy. Furthermore, the downregulation of deoxycytidine kinase could be associated with hypoxia-inducible factor 1 [alpha] as treatment with its inhibitor BAY87-2243 hampered the downregulation of deoxycytidine kinase expression under hypoxic conditions. Conclusions In conclusion, our data reveal that hypoxia-induced downregulation of deoxycytidine kinase represents one stroma-cell-independent mechanism of drug resistance to cytarabine in acute myeloid leukaemia. Article Note: Contributed equally to the work.
    Keywords: Acute Myeloid Leukaemia ; Hypoxia ; Drug Resistance ; Deoxycytidine Kinase ; Hypoxia‐Inducible Factor 1 Alpha
    ISSN: 0902-4441
    E-ISSN: 1600-0609
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  • 5
    Language: English
    In: Lung, August 2015, Vol.193(4), pp.567-70
    Description: Gremlin-1, an intrinsic antagonist of bone morphogenetic protein (BMP) signaling, has been implicated in the pathophysiology of pulmonary arterial hypertension (PAH). However, it is unknown whether gremlin-1 can be detected in the circulation of PAH patients and whether it is associated with patients' functional status and outcome. With a mean level of 242 ± 24 ng/ml, gremlin-1 levels of 31 PAH patients were significantly elevated compared to 151 ± 18 ng/ml in 15 age- and gender-matched healthy subject (p = 0.016). In PAH patients, increasing gremlin-1 levels correlated with N-terminal prohormone of brain natriuretic peptide levels (r = 0.608, p 〈 0.001) and inversely with the 6-minute walking distance (r = -0.412, p = 0.029). Furthermore, gremlin-1 significantly stratified survival in PAH patients (p = 0.015). Gremlin-1 may represent a new biomarker for PAH which can be linked directly to the underlying pathomechanism. Elevated levels of gremlin-1 are associated with patients' functional status and survival, thus gremlin-1 neutralization could represent a potential therapeutic strategy to increase BMPR2 signaling.
    Keywords: Hypertension, Pulmonary -- Blood ; Intercellular Signaling Peptides and Proteins -- Blood
    ISSN: 03412040
    E-ISSN: 1432-1750
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  • 6
    Language: English
    In: Cellular Signalling, February 2015, Vol.27(2), pp.373-381
    Description: The Hedgehog pathway plays an important role in the pathogenesis of several tumor types, including esophageal cancer. In our study, we show an expression of the ligand Indian hedgehog (Ihh) and its downstream mediator Gli-1 in primary resected adenocarcinoma tissue by immunohistochemistry and quantitative PCR in fifty percent of the cases, while matching healthy esophagus mucosa was negative for both proteins. Moreover, a functionally important regulation of Gli-1 by ErbB2–PI3K–mTORC signaling as well as a Gli-1-dependent regulation of Ihh in the ErbB2 amplified esophageal adenocarcinoma cell line OE19 was observed. Treatment of OE19 cells with the Her2 antibody trastuzumab, the PI3K–mTORC1 inhibitor NVP BEZ235 (BEZ235) or the knockdown of Akt1 resulted in a downregulation of Gli-1 and Ihh as well as in a reduction of viable OE19 cells . Interestingly, the Hedgehog receptor Smo, which acts upstream of Gli-1, was not expressed in OE19 cells and in the majority of primary human esophageal adenocarcinoma, suggesting a non-canonical upregulation of Gli-1 expression by the ErbB2–PI3K axis. To translate our findings into a therapeutic concept, we targeted ErbB2–PI3K–mTORC1 by trastuzumab and BEZ235, combining both compounds with the Gli-1/2 inhibitor GANT61. The triple combination led to significantly stronger reduction of tumor cell viability than cisplatinum or each biological alone. Therefore, concomitant blockage of the ErbB2–PI3K pathway and the Hedgehog downstream mediator Gli-1 may provide a new therapeutic strategy for esophageal cancer.
    Keywords: Esophageal Cancer ; Hedgehog ; Gli ; Non-Canonical ; Erbb2–Akt ; Biology
    ISSN: 0898-6568
    E-ISSN: 1873-3913
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