Dating carbonaceous matter in archean cherts by electron paramagnetic resonance.

Ancient geological materials are likely to be contaminated through geological times. Thus, establishing the syngeneity of the organic matter embedded in a mineral matrix is a crucial step in the study of very ancient rocks. This is particularly the case for Archean siliceous sedimentary rocks (cherts), which record the earliest traces of life. We used electron paramagnetic resonance (EPR) for assessing the syngeneity of organic matter in cherts that have a metamorphic grade no higher than greenschist. A correlation between the age of Precambrian samples and the shape of their EPR signal was established and statistically tested. As thermal treatments impact organic matter maturity, the effect of temperature on this syngeneity proxy was studied; cyanobacteria were submitted to cumulative short thermal treatment at high temperatures followed by an analysis of their EPR parameters. The resulting carbonaceous matter showed an evolution similar to that of a thermally treated young chert. Furthermore, the possible effect of metamorphism, which is a longer thermal event at lower temperatures, was ruled out for cherts older than 2 Gyr, based on the study of Silurian cherts of the same age and same precursors but various metamorphic grades. We determined that even the most metamorphosed sample did not exhibit the lineshape of an Archean sample. In the hope of detecting organic contamination in Archean cherts, a "contamination-like" mixture was prepared and studied by EPR. It resulted that the lineshape analysis alone does not allow contamination detection and that it must be performed along with cumulative thermal treatments. Such treatments were applied to three Archean chert samples, making dating of their carbonaceous matter possible. We concluded that EPR is a powerful tool to study primitive organic matter and could be used in further exobiology studies on low-metamorphic grade samples (from Mars for example).

Electron paramagnetic resonance study of a photosynthetic microbial mat and comparison with Archean cherts.

Organic radicals in artificially carbonized biomass dominated by oxygenic and non-oxygenic photosynthetic bacteria, Microcoleus chthonoplastes-like and Chloroflexus-like bacteria respectively, were studied by Electron Paramagnetic Resonance (EPR) spectroscopy. The two bacteria species were sampled in mats from a hypersaline lake. They underwent accelerated ageing by cumulative thermal treatments to induce progressive carbonization of the biological material, mimicking the natural maturation of carbonaceous material of Archean age. For thermal treatments at temperatures higher than 620 °C, a drastic increase in the EPR linewidth is observed in the carbonaceous matter from oxygenic photosynthetic bacteria and not anoxygenic photosynthetic bacteria. This selective EPR linewidth broadening reflects the presence of a catalytic element inducing formation of radical aggregates, without affecting the molecular structure or the microstructure of the organic matter, as shown by Raman spectroscopy and Transmission Electron Microscopy. For comparison, we carried out an EPR study of organic radicals in silicified carbonaceous rocks (cherts) from various localities, of different ages (0.42 to 3.5 Gyr) and having undergone various degrees of metamorphism, i.e. various degrees of natural carbonization. EPR linewidth dispersion for the most primitive samples was quite significant, pointing to a selective dipolar broadening similar to that observed for carbonized bacteria. This surprising result merits further evaluation in the light of its potential use as a marker of past bacterial metabolisms, in particular oxygenic photosynthesis, in Archean cherts.

[Optimization of a haematopoietic stem cell freezing process using a qualification protocol applicable to a programmable freezer]. / Optimisation d'un processus de congélation des cellules souches hématopoïétique par l'application d'un protocole de qualification d'un congélateur programmable.

BACKGROUND: The freezing phase is a critical step of the freezing process of the hematopoietic stem cells. To standardize the decrease of the temperature, the use of a programmable freezer is recommended. There is no available protocol, neither to describe exactly the validation of a programmable freezer, nor to prove the performance of the freezing/thawing step of the grafts. METHOD: We describe a validation protocol with three phases: first a qualification of installation, then an operational qualification and finally, a qualification of performance. The validation is performed in tandem between the freezer which is routinely used (Nicool Plus) and a new one (Freezal). RESULTS: With this protocol, we demonstrate the efficacy of the freezing program and its ability to assure the quality of the grafts reinjected to the patients, particularly in terms of cellular efficiency on CD34+ hematopoietic stem cells. On these cells, we measured a significant increase of cellular efficiency (+10%) after freezing with the Freezal. CONCLUSION: Here, we propose a validation protocol which is able to qualify a programmable freezer. This protocol can optimize the capability of the freezer and is able to prove its performance.

Change of the chemical composition and biodegradability of the Van Soest soluble fraction during composting: a study using a novel extraction method.

Van Soest fractionation is widely employed to characterize exogenous organic matter. The soluble fraction of Van Soest fractionation (SOL, extracted using hot water and then neutral detergent) often increases in line with compost maturity, although it is generally considered as labile. We have developed an alternative extraction method that comprises four successive steps (extraction using hot water, sodium tetraborate, dichloromethane/methanol and chelating resin) in order to clarify the chemical nature of the SOL fraction and explain its biodegradability. This method was tested on municipal solid waste compost sampled during the thermophilic phase (MSWi) and after 8 months of composting (MSWm). Both methods extracted similar proportions of organic matter. The composition of the residues was similar in MSWm although differences were noted for the extraction of polysaccharides and lipids in the case of MSWi. The hot water extractable fraction decreased during composting. Its high biodegradability in MSWi was linked to the high polysaccharide content revealed by pyrolysis-GC/MS and FTIR spectroscopy. The increase in the sodium tetraborate extractable fraction mainly explained the increase in the SOL fraction during composting. This was made up of N-containing compounds, polysaccharides and lipids in the immature compost, and a majority of N-containing compounds in the mature compost. During composting, the stabilization of organic matter in the SOL fraction extractable by sodium tetraborate and EDTA might principally involve N-containing structures through the formation of complexes of organic matter with metal ions, especially Ca(2+), which may be broken down during extraction of the Van Soest soluble fraction. These mechanisms still need to be investigated.

Comparison of the bulk geochemical features and thermal reactivity of kerogens from Mol (Boom Clay), Bure (Callovo-Oxfordian argillite) and Tournemire (Toarcian shales) underground research laboratories.

Deep argillaceous formations are potential repositories for the long-term disposal of nuclear waste because of their low permeability and high sorption capacity with respect to radioelements and heavy metals. Such sedimentary rocks contain organic matter, mostly macromolecular and insoluble (kerogen). Upon temperature elevation related to high-level long-lived radioactive waste disposal, the kerogen may release significant quantities of gaseous and liquid effluents, especially oxygen-containing ones, which may influence the ability of the clay to retain radionuclides. The aim of the present study is to assess the global geochemical features and the thermal reactivity of the kerogens isolated from samples collected in the Bure and Tournemire sites, France (Callovo-Oxfordian Clay and Toarcian Shales, respectively) and to draw comparisons with data previously obtained for the Mol site, Belgium (Boom Clay). The study is based on a combination of elemental, spectroscopic (FTIR, solid state (13)C NMR) and pyrolytic (Rock-Eval pyrolysis, Curie point pyrolysis-gas chromatography/mass spectrometry) analyses. Different levels of maturity and resulting differences in the relative abundance of oxygen-containing groups were thus observed for the three kerogens. This is linked with differences in their ability to generate CO(2) and various oxygen-containing, low molecular weight, water-soluble compounds under thermal stress, decreasing from Mol to Bure and to Tournemire.

European register of babies born to mothers with antiphospholipid syndrome.

This prospective multicentric register was initiated by the European Forum of Antiphospholipid Antibodies (APL) in 2003 after approval by local ethic committees. This register allows the investigation of infants after written informed parental consent. It collects mothers' clinical pattern of antiphospholipid syndrome (APS), course and outcome of pregnancy, treatment and immunological status. For the babies, clinical and immunological examinations are performed at birth; neurodevelopmental conditions followed up to five years. A re-evaluation of lupus anticoagulant (LA), anticardiolipin (ACL) or other antibodies will be done if they are positive at birth to follow their kinetics. A descriptive and a case control study of babies with versus without APL at birth will be possible after the inclusion of 300 cases.

Characterization and comparison of two ligno-cellulosic substrates by (13)C CP/MAS NMR, XPS, conventional pyrolysis and thermochemolysis.

Ligno-cellulosic substrates (LCSs) isolated from wheat straw and bran exhibit high complexing capacities and may have important applications for metal removal from industrial effluents. These two LCSs were examined in the present work by spectroscopic and pyrolytic methods (solid state cross polarization magic angle spinning (CP/MAS) (13)C NMR, XPS, conventional Curie pyrolysis (Cupy)/GC/MS, and TMAH thermochemolysis/GC/MS). This combined study highlighted the limitation of some of the above methods when applied to ligno-cellulosic materials and the resulting biases and the usefulness of TMAH thermochemolysis. A large difference in composition was observed between bran- and straw-LCS due to a much higher contribution of alkyl moieties in the former. These moieties correspond to fatty acids esterified to the ligno-cellulosic macromolecular structure and such carboxylic functions should play an important role for metal complexation.

Changes in the organic composition of wastewater during biological treatment as studied by NMR and IR spectroscopies.

Despite its importance, relatively little is known about the composition and fate of wastewater organic matter (OM) in treatment plants. Monitoring the chemical changes in OM during activated sludge treatment can improve our knowledge of the processes involved in the biological elimination of OM. Direct chemical analyses of treated water OM typically account for about 20% of the OM, and structural information was obtained in this study using Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared (FTIR) spectroscopic techniques. Distinct changes in the OM during wastewater biological treatment were underlined. 13C and 1H NMR showed that aromatic carbons were minor constituents of the samples. Alkyl chains exhibited a more highly branched character in treated water, as compared to long chain aliphatic carbons present in wastewater. Carboxyl signals in the 13C NMR spectrum of wastewater could be due to peptide bonds in proteins, whereas in the treated water spectrum, this signal could be related to the presence of non-proteinaceous nitrogen. Besides the non-degraded compounds, treated water OM could contain recondensation products of simple molecules. Their refractory character probably derives from their complex structures rather than from particular chemical functions, as suggested by the lack of fundamental differences in the chemical structures of wastewater and treated water OM.

[Lipids from fossil plants and their relation to modern plants. Example s of Cenomanian flora from Anjou and Bohemia]. / Les lipides des plantes fossiles dans leurs rapports avec les plantes actuelles. Exemples des flores cénomaniennes d'Anjou et de Bohême.

Comparative analyses of lipids from fossil plants and from their extant counterparts were undertaken in order to test the taxonomic significance of lipids in palaeobotany. The comparison between lipids from a fossil Ginkgoaceae, Eretmophyllum andegavense, and its extant counterpart, Ginkgo biloba, revealed the presence of original molecules, dimethoxyalkylcoumarins, in lipids from both plants. Such compounds confirm, on chemical grounds the relationship between these extant and fossil Ginkgoaceaes. Moreover, differences in n-alkane distribution between E. andegavense and E. obtusum which are very similar morphologically, confirm that these fossil plants do not belong to the same species. Furthermore, comparative analyses of a fossil Cheirolepidiaceae, Frenelopsis alata, and its extant counterpart, the Cupressaceae Tetraclinis articulata, revealed some similarities between these two species although they do not belong to the same family. Otherwise, comparative analyses of fungi-infected and uninfected samples of F. alata demonstrated that these micro-organisms can significantly affect the chemical composition of fossil plant lipids. In conclusion, even if chemical analyses alone are not sufficient to determine the genus or species of a given fossil plant, they can precise the taxonomy of some specimens that have been previously studied by palaeobotanists.

Prevalence of rheumatic manifestations and antineutrophil cytoplasmic antibodies in haematological malignancies. A prospective study.

OBJECTIVE: To evaluate the prevalence of antineutrophil cytoplasmic antibodies (ANCA) and rheumatic manifestations associated with chronic haematological malignancies. METHODS: Two groups of patients were prospectively studied (group I: 60 patients with myelodysplastic syndromes and group II: 140 patients with lymphoid malignancies) for clinical 'immune' manifestations and ANCA. RESULTS: In the myelodysplastic group, six patients had ANCA-negative systemic medium-size vasculitis, one had systemic vasculitis with cytoplasmic ANCA, one relapsing polychondritis, one giant cell arteritis, one polymyalgia rheumatica, one polyarthritis and two fasciitis. In group II, two patients had ANCA-negative systemic vasculitis, two had leucocytoclastic vasculitis associated with tuberculosis, two had polyarthritis, one polymyalgia rheumatica and one giant cell arteritis. Six sera were ANCA-positive with perinuclear pattern in four cases, atypical pattern in one and cytoplasmic pattern in one. Two sera had anti-myeloperoxidase (MPO) specificity, and others had no known specificity; none had anti-proteinase 3 (PR3) specificity. Global prevalence of ANCA in our cohort was 3%, similar to the French general population. CONCLUSION: Polyarteritis nodosa-type systemic vasculitis and polymyalgia rheumatica were the most frequent findings (18%) in myelodysplastic syndromes and particularly in chronic myelomonocytic leukaemia. ANCA were not helpful for the diagnosis of vasculitis. Vasculitis associated with infection, in particular tuberculosis, must be ruled out.

Mcl-1 and Bcl-xL are co-regulated by IL-6 in human myeloma cells.

Multiple myeloma (MM) is a slowly proliferative malignancy in which malignant plasma cells accumulate within the bone marrow. The expression of several anti-apoptotic proteins was evaluated by immunoblotting in human myeloma cell lines and in highly purified native myeloma cells. Expression of Bcl-xL, Mcl-1 and Bcl-2 was found in most of the samples; expression of Bcl-xL and Mcl-1 seemed to be related on myeloma cells. In a system of apoptosis by growth factor deprivation on myeloma cells, we showed that the effect of Bcl-2 seemed minimal whereas Mcl-1 and Bcl-xL were tightly regulated by interleukin (IL)-6. These findings underline the important role of Mcl-1 and Bcl-xL instead of Bcl-2 in IL-6-induced survival of myeloma cells.

Zoledronate is a potent inhibitor of myeloma cell growth and secretion of IL-6 and MMP-1 by the tumoral environment.

Bisphosphonates have recently been introduced in the therapeutic armamentarium for the long-term treatment of patients with multiple myeloma (MM). These pyrophosphate analogs not only reduce the occurrence of skeletal-related events but also provide patients with a clinical benefit and improve the survival of some of them. We investigated the effects of two bisphosphonates, pamidronate and zoledronate, on both myeloma cells and bone marrow stromal cells (BMSCs). We show here that both bisphosphonates induce both myeloma cell and BMSC apoptosis. Furthermore, at lower concentrations, they induce a significant inhibition (40% and 60%, respectively) of the constitutive production of interleukin-6 (IL-6) by BMSCs. We have recently shown that BMSCs produce MMP-1, the major metalloproteinase involved in the initiation of bone resorption, production up-regulated by IL-1beta. Here, we demonstrate that zoledronate significantly inhibits MMP-1 production by BMSCs stimulated with IL-1beta more efficiently than pamidronate. However, zoledronate and to a lesser extent pamidronate are responsible for an up-regulation of MMP-2 secretion by BMSCs. MMP-2 is involved both in bone resorption and in the metastatic process. In conclusion, the apoptosis of myeloma cells and BMSCs and the inhibition of both IL-6 and MMP-1 production induced by bisphosphonates, mainly zoledronate, could have antitumoral effects in patients with MM. However, the up-regulation of MMP-2 secretion observed in vitro suggests a putative risk of tumor cell dissemination in vivo when using these new potent bisphosphonates. This potentially deleterious effect could be abolished by combining bisphosphonates with metalloproteinase inhibitors.