Seasonal variations in vitamin D levels in melanoma patients: a single-centre prospective pilot comparative study

in Journal of the European Academy of Dermatology & Venereology (2012), 26(5), 651-3

BACKGROUND: More than 90% of vitamin D synthesis is dependent on UV exposure. Photosensitive disorders such as lupus erythematosus, protoporphyria and xeroderma require strict sun avoidance, and vitamin D ... [more ▼]

BACKGROUND: More than 90% of vitamin D synthesis is dependent on UV exposure. Photosensitive disorders such as lupus erythematosus, protoporphyria and xeroderma require strict sun avoidance, and vitamin D deficiency has been demonstrated in these patients. Melanoma patients are also instructed to avoid sun exposure and may hence be expected to be vitamin D deficient. MATERIALS AND METHODS: Winter and summer vitamin D levels were compared in a group of melanoma patients (n =61) and age- and phototype-matched controls (n = 53) without photosensitive disorders. RESULTS: Oral supplementary vitamin D intake was reported in 32.7% of the melanoma patients and in 15.1% in the control group. Despite oral supplementation, only 25% of the melanoma patients and the controls presented with vitamin D levels of 30 ng/mL or higher. In non-supplemented subjects in the melanoma and control groups, respectively, mean winter vitamin D levels were below the recommended threshold at 12.6 ng/mL vs. 13.2 ng/mL, respectively, but not statistically different. These values increased significantly in both groups during the summer to 24.6 and 23.8 ng/mL respectively. CONCLUSION: Unexpected, significant increases in vitamin D levels were seen in melanoma patients during summer, suggesting non-adherence with photoprotective measures and reflecting a heliophilic behaviour. Vitamin D supplementation is recommended in melanoma patients during both winter and summer. [less ▲]

Comparison between Optimal Interpolation (OI) and Data-Interpolating Variational Analysis (Diva) for the generation of analysis and error gridded fields

Poster (2012, April 24)

Impact of cultivation practices on soil respiration

Poster (2012, February 08)

In addition to its, evident, food supply function, agriculture is subjected to various pressures and has to respond to many challenges like reducing its CO2 emissions, maintaining or improving the soil ... [more ▼]

In addition to its, evident, food supply function, agriculture is subjected to various pressures and has to respond to many challenges like reducing its CO2 emissions, maintaining or improving the soil quality, maintaining productivity, sequestrating of the carbon stock in soil... Cultivation practices are known to induce a modification of soil organic matter quantity, quality and spatial distribution, which may impact dry matter decomposition kinetics. In order to bring answers to these questions, a multidisciplinary project (SOLRESIDUS) was set up by the University of Liege, Gembloux Agro-Bio Tech in collaboration with Walloon Agricultural Research Centre (CRA-W). The aim was to investigate the impact of cultivation practices (tillage and residue restitution) on crop growth, yield and environment, as well as on soil properties and on activities. In the present study, we focused on the impacts on soil CO2 fluxes. The experimental site is situated in Gembloux, in the Belgian loamy region. The plot is divided into 4 latin squares where two tillage modalities (plough after 2 stubble breaking vs only 2 stubble breaking) and two straw management practices (restitution vs. exportation) were compared. For 3 years, soil respiration was measured with automatic and manual dynamic soil chambers. Moreover, soil respiration was measured as well in cropping zone (total respiration) as in root exclusion zones created with root exclusion cylinders (heterotrophic respiration). As first results, we observed: -a significantly higher flux in plots with residue restitution, which is clearly explained by the larger amount of organic carbon prone to decomposition; -a decrease of standardized heterotrophic respiration (linked with residue decomposition) during growing seasons; -no significant differences in soil respiration between tillage modalities after 3 growing seasons. The experiment is still in progress, more years being necessary in order to evaluate the long-term impacts of cultivation practices on soil respiration. [less ▲]

The proteolytic activity of MT4-MMP is required for its proangiogenic and pro-metastatic promoting effects

in International Journal of Cancer = Journal International du Cancer (2012), 131(7), 1537-1548

MT4-MMP expression in breast adenocarcinoma stimulates tumor growth and metastatic spreading to the lung. However whether these pro-tumorigenic and pro-metastatic effects of MT4-MMP are related to a ... [more ▼]

MT4-MMP expression in breast adenocarcinoma stimulates tumor growth and metastatic spreading to the lung. However whether these pro-tumorigenic and pro-metastatic effects of MT4-MMP are related to a proteolytic action is not known yet. Through site directed mutagenesis MT4-MMP has been inactivated in cancer cells through Glutamic acid 249 substitution by Alanine in the active site. Active MT4-MMP triggered an angiogenic switch at day 7 after tumor implantation and drastically accelerated subcutaneous tumor growth as well as lung colonization in RAG -/- mice. All these effects were abrogated upon MT4-MMP inactivation. In sharp contrast to most MMPs being primarily of stromal origin, we provide evidence that tumor-derived MT4-MMP, but not host-derived MT4-MMP contributes to angiogenesis. A genetic approach using MT4-MMP-deficient mice revealed that the status of MT4-MMP produced by host cells did not affect the angiogenic response. Despite of this tumor intrinsic feature, to exert its tumor promoting effect, MT4-MMP requires a permissive microenvironment. Indeed, tumor-derived MT4-MMP failed to circumvent the lack of an host angio-promoting factor such as lasminogen activator inhibitor (PAI-1). Overall, our study demonstrates the key contribution of MT4-MMP catalytic activity in the tumor compartment, at the interface with host cells. It identifies MT4-MMP as a key intrinsic tumor cell determinant that contributes to the elaboration of a permissive microenvironment for metastatic dissemination [less ▲]