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Objectives To establish recommendations on immunization for patients with multiple sclerosis (MS). Background Vaccines have been suspected in the past to trigger MS and relapses. With the extension of the immunoactive treatment arsenal, other concerns have been raised more recently about an increased risk of infection or a decreased effectiveness of immunization in immunosuppressed patients. Methods The French Group for Recommendations into Multiple Sclerosis (France4MS) performed a systematic search of papers in Medline and other university databases (January 1975–June 2018). The RAND/UCLA appropriateness method was chosen to review the scientific literature and to formalize the degree of agreement among experts on 5 clinical questions related to immunization and MS. Readers from the steering committee conducted a systematic analysis, wrote a critical synthesis and prepared a list of proposals that were evaluated by a rating group of 28 MS experts. The final version of the recommendations was finally reviewed by a reading group of 110 health care professionals and classified as appropriate, inappropriate or uncertain. Results Neurologists should verify the vaccination status as soon as MS is diagnosed and before disease-modifying treatments (DMTs) are introduced. The French vaccination schedule applies to MS patients and seasonal influenza vaccination is recommended. In the case of treatment-induced immunosuppression, MS patients should be informed about the risk of infection and the vaccination standards of the French High Council of Health should be applied. Live attenuated vaccines are contra-indicated in patients recently treated with immunosuppressive drugs, including corticosteroids; other vaccines can be proposed whatever the treatment, but their effectiveness may be partly reduced with some drugs. Conclusion Physicians and patients should be aware of the updated recommendations for immunizations of patients with MS.

Congenital myasthenic syndromes are rare heterogeneous hereditary disorders, which lead to defective neuromuscular transmission resulting in fatigable muscle weakness. Post-synaptic congenital myasthenic syndromes are caused by acetylcholine receptor kinetic abnormalities or by acetylcholine receptor deficiency. Most of the congenital myasthenic syndromes with acetylcholine receptor deficiency are due to mutations in acetylcholine receptor subunit genes. Some have recently been attributed to mutations in the rapsyn gene. Here, we report the case of a 28-year-old French congenital myasthenic syndrome patient who had mild diplopia and fatigability from the age of 5 years. His muscle biopsy revealed a marked reduction in rapsyn and acetylcholine receptor at neuromuscular junctions together with a simplification of the subneural apparatus structure. In this patient, we excluded mutations in the acetylcholine receptor subunit genes and identified the homozygous N88K rapsyn mutation, which has already been shown by cell expression to impair rapsyn and acetylcholine receptor aggregation at the neuromuscular junction. The detection of the N88K mutation at the heterozygous state in five of 300 unrelated control subjects shows that this mutation is not infrequent in the healthy population. Electrophysiological measurements on biopsied intercostal muscle from this patient showed that his rapsyn mutation-induced fatigable weakness is expressed not only in a diminution in acetylcholine receptor membrane density but also in a decline of endplate potentials evoked at low frequency.

Mutations in Notch3 cause CADASIL (cerebral autosomal dominant adult onset arteriopathy), which leads to stroke and dementia in humans. CADASIL arteriopathy is characterized by major alterations of vascular smooth muscle cells and the presence of specific granular osmiophilic deposits. Patients carry highly stereotyped mutations that lead to an odd number of cysteine residues within EGF-like repeats of the Notch3 receptor extracellular domain. Such mutations may alter the processing or the trafficking of this receptor, or may favor its oligomerization. In this study, we examined the Notch3 expression pattern in normal tissues and investigated the consequences of mutations on Notch3 expression in transfected cells and CADASIL brains. In normal tissues, Notch3 expression is restricted to vascular smooth muscle cells. Notch3 undergoes a proteolytic cleavage leading to a 210-kDa extracellular fragment and a 97-kDa intracellular fragment. In CADASIL brains, we found evidence of a dramatic and selective accumulation of the 210-kDa Notch3 cleavage product. Notch3 accumulates at the cytoplasmic membrane of vascular smooth muscle cells, in close vicinity to but not within the granular osmiophilic material. These results strongly suggest that CADASIL mutations specifically impair the clearance of the Notch3 ectodomain, but not the cytosolic domain, from the cell surface.

The transfers and origins of dissolved inorganic carbon (DIC) were studied for a year in a soil–spring–stream system in the Strengbach catchment, Vosges mountains, France. This 80 ha experimental research basin is located on the eastern side of the mountains, at an altitude ranging from 883 to 1146 m.a.s.l. and is mainly covered by spruce (80%). Brown acid and podzolic soils developed on a granitic basement, and, as a result, the DIC originates solely from CO2 generated by oxidation of soil organic matter. The ( δ 13 C DIC ) in catchment waters is highly variable, from about −22‰ in the springs and piezometers to about −12‰ in the stream at the outlet of the catchment. In the springs, pronounced seasonal variations of δ 13 C DIC exist, with the DIC in isotopic equilibrium with the soil CO2 that has estimated δ 13 C of about −24‰ in winter and −20‰ in summer. These seasonal variations reflect an isotopic fractionation that seems only induced by molecular diffusion of soil CO2 in summer. In stream water, seasonal variations are small and the relatively heavy DIC (−12‰ on average) is a result of isotopic equilibration of the aqueous CO2 with atmospheric CO2.

Capillary electrophoretic methods (CZE, CIEF) have been found to be useful tools for the analysis of the electrophoretic behaviour of anionic polyelectrolytes like humic substances. The humic substances give a Gaussian distribution of the detection signals around an average electrophoretic mobility (AEM) corresponding to the charge density distribution of the humic substances governed by their molecular size and their acidities. Natural humic substances as well as phenolic polymerisates are only present as anions and the presented electrophoretic methods can be used as a tool for the rapid evaluation of their relative charge densities, an important parameter when studiying their reactivity towards organic and metallic species.

We describe a patient found to have acute diffuse and reversible encephalopathy on magnetic resonance imaging (MRI) associated with cholesterol emboli syndrome (CES). The initial MRI showed extensive white matter, basal ganglia and cortical damage without evidence of brain infarction. Dramatic clinical and MRI improvement was observed with corticosteroids. Pathologically, cholesterol crystal emboli were found in the lumen of skin and brain arteries and were associated with varying degrees of inflammation of the arteriole wall. This case suggests that CES may be responsible for extensive, acute and reversible encephalopathy underlined by an inflammation of brain arteries.

Field experiments were carried out in order to quantify the variations of the traction and tillage forces on a mole plough, in the case of four clayey soils of Eastern France. The same tractor-implement system, the same forward working speed (1 m s−1) and the same length of ploughing (20 m) were used. Specially designed strain gauge transducers applied to the system delivered a signal which was numerised and analysed in terms of power spectral density (PSD) function. The frequency composition of the traction and tillage forces consisted of interactions between soil and tool as well as vibrations of the tractor-implement system. Low frequencies (0–2 Hz range) were related to the random property of soil rupture and heterogeneity, whereas random vibration frequencies of the system were shown in the higher frequency range (2–15 Hz). The dominant distance of soil fracture was close to the working depth. The frequency analysis of interaction forces represented a combination of the influence of the soil, the mole plough and the operating conditions, so this method should provide a way to assess the performance of working parts and mole channel stability.

In soils of the eastern Amazonian forest, modifications in soil organic matter (SOM) contents as a consequence of deforestation and pasture installation were investigated. Profile distribution of total organic carbon (C) and nitrogen (N), and of 13C isotope abundance (expressed in δ13C%o units) were compared. The two soils, one under native forest and the other one after ten years under pasture of Pennisetum purpureum had similar C/N values, which slightly decreased with increasing depth, from 13.6 to 11.9–12.7 within the first 40 cm. In the pasture soil, the C content was slightly lower than in the forest soil, and reached 29 t ha−1 compared with 31 t ha−1, and 15 t ha−1 compared with 16 t ha−1, in the 0–20 and 20–40 cm layers, respectively. The δ13C values reflected the origin of SOM, from either the forest (which had a C3 photosynthetic cycle), or the pasture (which had a C4 cycle). They were higher by at least 6.5 and 1.5 units, in the respective 0–10 and 10–20 cm layers of the pasture soil, than in the corresponding layers of the forest soil. These δ13C values were used to estimate the proportions of C derived from the forest (Cdf) and from the pasture (Cdp). The calculations clearly indicated a strong input of Cdp, which reached 46–49% and 21–24% of total C in the respective layers. Particle size fractionation showed that SOM changes were predominant in the upper soil layer (0–10 cm), and vanished with increasing depth: in the pasture soil, the coarse organic residues accumulated, whereas the amount of C in the finest fractions decreased, which suggested a slowing down in humification processes. In the forest soil, the δ13C values were lower in the coarsest than in the finest fractions, the latter being less affected than the coarsest ones by the vegetation change; in the 0–10 cm layer, these values increased by about 7–10 units in the sand-size fraction, and only 4–5 units in the clay-size fraction. Thus, the replacement of Cdf by Cdp was greater in the sand-size fraction (55–65% of total C), than in the clay-size fraction (34–45% of total C). Based on 14C dating, the oldest pool (i.e. that of mean age 5000 years) of forest SOM was calculated at each depth. In the soil surface, it was still smaller than the more labile fraction of Cdf, and represented about 17% and 26% of total C in the 0–10 cm and 0–20 cm layers, respectively.

The Amazon is the largest stream in the world. Its basin covers at least 7 · 10 6 km 2 , which represents ∼ 5% of the global continental area and almost 70% of the area of the continents localized in the equatorial zone, between 5°S and 5°N of latitude. The global tropical moist forest covers ∼ 9.35 · 10 6 km 2 , so that the Brazilian evergreen rain forest represents at least 50% of this area. At Obidos, the most accessible downstream station for collecting data, the area concerned is 4.619 · 10 6 km 2 . The purpose of these two extended abstracts is to show how changes and oscillations of climate can significantly affect erosion as well as carbon and nitrogen cycles, and may also mask the degradations of the environment due to deforestation.

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy) is a small-artery disease of the brain caused by NOTCH3 mutations that lead to an abnormal accumulation of NOTCH3 within the vasculature. We aimed to establish whether immunostaining skin biopsy samples with a monoclonal antibody specific for NOTCH3 could form the basis of a reliable and easy diagnostic test. We compared the sensitivity and specificity of this method in two groups of patients suspected of having CADASIL with complete scanning of mutation-causing exons of NOTCH3 (in a retrospective series of 39 patients) and with limited scanning of four exons that are mutation hotspots (prospective series of 42 patients). In the retrospective series skin biopsy was positive in 21 (96%) of the 22 CADASIL patients examined and negative in all others; in the prospective series, seven of the 42 patients had a positive skin biopsy whereas only four had a mutation detected by limited NOTCH3 scanning. Our immunostaining technique is highly sensitive (96%) and specific (100%) for diagnosis of CADASIL.

International audience; OBJECTIVE: To evaluate whether very early neurologic improvement (VENI) after intravenous (i.v.) recombinant tissue plasminogen activator (rt-PA) perfusion in patients with acute ischemic stroke (AIS) predicts favorable outcome at 3 months. DESIGN: Retrospective analysis of prospective data. SETTING: Stroke registry at the Stroke Unit, Tenon University Hospital. PATIENTS: We analyzed consecutive patients with AIS treated with i.v. rt-PA between November 11, 2002, and December 24, 2007. MAIN OUTCOME MEASURES: VENI at 1 hour was defined as a National Institute of Health Stroke Scale score of 0 at the end of rt-PA perfusion or an improvement of 5 or more points compared with baseline. Favorable outcome was defined as a modified Rankin Scale score of 1 or less at 3 months. RESULTS: Of 120 patients with AIS treated with i.v. rt-PA, 22 (18.3%) had VENI after i.v. rt-PA perfusion. Favorable outcome was observed in 15 patients with VENI (68.2%) and in 29 patients without VENI (29.6%) (P < .001). No symptomatic intracerebral hemorrhage occurred in patients with VENI. Mortality rates were 0% in the patients with VENI and 17.3% in patients without VENI. Baseline scores for VENI (adjusted odds ratio, 6.23; 95% confidence interval, 2.03-19.13; P = .001) and the National Institute of Health Stroke Scale (0.83; 0.76-0.91; P < .001) were the only 2 factors associated with favorable outcome (modified Rankin Scale score of ≤1). CONCLUSIONS: VENI at the end of i.v. rt-PA perfusion in patients with AIS independently predicts favorable outcome at 3 months.

Binding of organic pollutants to water-soluble, low-molecular weight humic substances increases their mobility in soil and their leaching, whereas binding to high-molecular weight humic substances results in unextractable residues. Water-soluble pollutants in leachate may be bound to low-molecular weight humic material, or may be free water-soluble conversion products that are slowly released from a soil-bound form, as shown for a conversion product of the insecticide aldrin. Unextractable soil-bound 4-chloroaniline was isolated by supercritical methanol extraction 16 years after application of the phenylurea herbicide buturon to soil. Biodegradation and bioavailability of unextractable soil-bound residues are greatly reduced as compared to the free compounds. For some chlorinated anilines and phenols, biomineralization and plant uptake was shown to be highest for residues bound in fulvic acids and lowest for those in humic acids. Model experiments demonstrate that chlorinated anilines form covalent bonds with humic acid precursors.

Humus organic and organo‐mineral components prevail in the retention and movement of most pollutants in soils. Numerous kinds of physical, chemical, sometimes unknown bindings, are involved, especially in the fixation of pesticides residues. Fractionation methods attempt to improve knowledge about the relation between the distribution of pollutants and the nature of native compounds in soils.

At the CPATU-EMBRAPA Experimental Center of Capitao Poco, Para, Eastern Amazonia, the effects of clearing and annual cropping on soil physical and cbemical characteristics were studied. ln this area soils are predominantly medium-textured latosols and podzolic latosols, according to the Brazilian soil classification. The selected adjacent sites fall in a sequence from native to freshly burnt, forest, to cultivated for one and five years, for two years and fallow for three years. ln each position on the sequence a pedon was described, sampled, and compared to three reference pedons under native forest, characterized according to drainage intensity. Burning itself had only slight effects, except on the litter material, which was entirely substituted by ash and charcoal residues. With increasing duration of cultivation, the thickness of the surface A11 horizon decreased, as a result of increasing density and cohesion. Mottling increased, and reached the A3 horizon, whereas the flocculation degree, which expresses the proportion of non water-dispersible clay particles, decreased. Residues burnt above ground desappeared rapidly; afier five years cropping soil organic carbon content decreased by 14% in the whole profile, and 24% in the 0-20cm soillayer. Burning was found to bring about an increase of 2.5 units of surface soil pH, and to release exchangeable bases, which progressively migrate, resulting in a decrease of exchangeable aluminium, even in the deeper soillayers, and afier five years of cropping. Afier three years of fallow following two years of cropping, the vegetation underwent regeneration; organic residues were produced, soil biology was stimulated and there was a progressive return to initial soil characteristics.

In spite of obvious differences in total humus content, and in the relative proportions of humus fractions from one soil to another, the relationships between the ecology and chemical nature of humus are still incompletely elucidated. Most studies centre upon the polymeric nature of humic acids, the mechanisms involved in their formation, and their interactions with non-humic biomolecules. Anthropic alterations of the ecosystem for agricultural purposes modify soil humus content and composition, sometimes with restricted renewal through crop root exudates and residues. In the tropics after forest clearing, even soil fertility can be affected; the amount of humic acids strongly decreases and they are renewed at a much slower rate than any other fraction. This decrease was studied in actual field situations, using natural 13C isotope measurements.

Congenital Myasthenic Syndromes (CMS) are a heterogeneous group of diseases caused by genetic defects affecting neuromuscular transmission. The twenty five past Years saw major advances in identifying different types of CMS due to abnormal presynaptic, synaptic, and postsynaptic proteins. CMS diagnosis requires two steps: 1) positive diagnosis supported by myasthenic signs beginning in neonatal period, efficacy of anticholinesterase medications, positive family history, negative tests for anti-acetylcholine receptor (AChR) antibodies, electromyographic studies (decremental response at low frequency, repetitive CMAP after one single stimulation); 2) pathophysiological characterisation of CMS implying specific studies: light and electron microscopic analysis of endplate (EP) morphology, estimation of the number of AChR per EP, acetylcholinesterase (AChE) expression, molecular genetic analysis. Most CMS are postsynaptic due to mutations in the AChR subunits genes that alter the kinetic properties or decrease the expression of AChR. The kinetic mutations increase or decrease the synaptic response to ACh resulting respectively in Slow Channel Syndrome (characterized by a autosomal dominant transmission, repetitive CMAP, refractoriness to anticholinesterase medication) and fast channel, recessively transmitted. AChR deficiency without kinetic abnormalities is caused by recessive mutations in AChR genes (mostly epsilon subunit) or by primary rapsyn deficiency, a post synaptic protein involved in AChR concentration. Recently, mutations in SCN4A sodium channel have been reported in one patient. AChE deficiency is identified on the following data: recessive transmission, presence of repetitive CMAP, refractoriness to cholinesterase inhibitors, slow pupillary response to light and absent expression of the enzyme at EP. This synaptic CMS is caused by mutations in the collagenic tail subunit (ColQ) that anchors the catalytic subunits in the synaptic basal lamina. The most frequent presynaptic CMS is caused by mutations of choline acetyltransferase. Several CMS are still not characterized. Many EP molecules are potential etiological candidates. In these unidentified cases, other methods of investigations are required: linkage analysis, when sufficient number of informative relatives are available, microelectrophysiological studies performed in intercostal or anconeus muscles. Prognosis of CMS, depending on severity and evolution of symptoms, is difficult to assess, and it cannot not be simply derived from mutation identification. Most patients respond favourably to anticholinesterase medications or to 3,4 DAP which is effective not only in presynaptic but also in postsynaptic CMS. Specific therapies for slow channel CMS are quinidine and fluoxetine that normalize the prolonged opening episodes. Clinical benefits derived from the full characterisation of each case include genetic counselling and specific therapy.

Congenital myasthenic syndromes (CMS) constitute a group of rare diseases heterogeneous both in terms of their mode of hereditary transmission (recessive and dominant forms) and their pathophysiology (with presynaptic, synaptic, and postsynaptic defects). They are responsible for dysfunction of neuromuscular transmission giving rise to a condition of muscle weakness which is accentuated by exertion. In most cases, CMS begin in early childhood but later onset in adulthood is possible. Severity also varies from severe with respiratory failure to mild expression.1,2 The majority of CMS primarily affect postsynaptic function and are the result of mutations located in the muscle acetylcholine receptor (AChR) subunit genes that lead to kinetic abnormalities or to AChR deficiency. For example, an increased response occurs in the slow channel syndromes associated with dominant mutations in AChR subunits delaying channel closure or increasing the affinity of the receptor for acetylcholine. However, the most commonly encountered CMS is a deficiency in AChR which occurs with recessive mutations. Most of these mutations are located in the AChR e subunit.3,4 Recent advances have shown that mutations in rapsyn are also involved in recessive forms of postsynaptic CMS and cause AChR deficiency.5 Rapsyn is a 43 kDa postsynaptic protein involved in development and maintenance of the molecular architecture of the postsynaptic membrane by participating in the clustering of AChR after binding of neural agrin to its muscle specific receptor tyrosine kinase, MuSK.6,7 The rapsyn gene ( RAPSN ) has been mapped to chromosome 11p11.2 p11.1 and comprises eight exons.8 The primary structure of rapsyn is predicted to contain several functional domains such as an N-terminus myristoylation signal, seven tetratricopeptide repeats (residues 6-279), a coiled-coiled domain (298-331), a cysteine rich RING-H2 domain (363-402), and a serine phosphorylation site at codon 406.9,10 The aim of this …

Publisher Summary This chapter discusses the soil humus and total organic carbon (OC) content. It reviews the results concerning the changes in soil organic matter (SOM) chemical nature regardless of the technical methods used. Information about C cycling and storage in soils is also given. Soil humus is characterized by its amounts and properties such as water retention capacity, aggregation and cementing agent, and the ability to absorb both nutrients and contaminants. The uncontrolled decrease in soil humus content affects soil water regime, aeration, fertility, and purifying capacity. The chapter focuses on the main soil types and the areas of the world where they are found, and considers the distribution of humus in these soils and areas, and the factors that can affect it. It shows that soil humus is the main OC reservoir at the earth surface and that its distribution is not comparable with the surface distribution of taxonomic units. This observation reviews humus characteristics in the four soil units that contribute to more than 80% of total earth OC: podzols, histosols, chernozems, and ferralsols.

Les differentes voies de dispersion de l'atrazine dans les sols et l'environnement sont examinees, et les resultats discutes en relation avec les methodes d'approche respectives. Pour ce qui concerne la volatilisation, les donnees de la litterature sont limitees et discordantes, car les mesures sont le plus souvent menees dans des conditions tres eloignees de la realite: les valeurs rencontrees pour cette voie de transfert vont, suivant les auteurs, de 0,017 a 60% de la dose appliquee au sol en 72 h (...)

A comparative study was performed in the Oriental Amazon region of Brazil, on an experimental area of yellow latosol and red-yellow podzolic soils. Taking the forest soil as a reference, the chemical, physical, and micromorphological changes occurring after sequential burning, tillage and fallow-land were studied. Deforestation and tillage were responsible for a decreasing content and qualitative changes in organic matter; fulvic acid content first increased, then humic acid content decreased, giving rise to an increasing destruction of clay/organic complexes in the A horizon. As a result, a greater dispersion and migration of fine particles occurred, causing the obstruction of macropores and an increase in bulk density. Crop production decreased in two years, and the soil had to be abandoned. A secondary vegetation developed, and yielded organic residues which stimulated faunal activity. After three years under fallow, the above observed soil degradation processes were partially reversed.

The fact that a portion of pesticide residues remains in soil after solvent extraction, particularly in organic soils, indicates that some of the pesticides may be incorporated into soil humus. Studies concerning the formation of these “bound” residues under field conditions are difficult, and one alternative is to use model humic acids for investigating pesticide behaviour in soils. A humic-like polymer was synthesized by oxidation of catechol in the presence of atrazine in a phosphate buffer (pH 6 or 7). The reaction mixture was then acidified to pH 1.5, precipitating “humic acids” while “fulvic acids” remained in solution. The different fractions were extracted with chloroform to remove extractable residues of atrazine, then submitted to carbon and nitrogen determination, spectroscopic analysis and chromatography. The results suggest that atrazine is partly adsorbed by the model humic acid, then extractable, and partly non-extractable with chloroform. The nature of the different binds or associations of atrazine with synthetic polymers are discussed.

The consequences of burning and deforestation on soil organic matter (SOM) content were studied on two managed areas of Oxisol (Yellow Latosol) located near Manaus, in Central Amazonia. The variations of organic carbon (OC) content were studied on the 2 mm sieved fraction of surface soils collected under natural forest, before and after slash and burning, and under pasture of Brachiaria humidicola established for one, two and eight years. Under natural forest, OC content reached maximal values of 28 T.ha−1 in the 0–3 cm layer, 62 T.ha−1 in the 3–20 cm layer, and decreased rapidly with depth. Burning removed about 4 T.ha−1 of OC, chiefly from the 0–3 cm soil layer, but this loss was recovered after one year of pasture. Decreases of about 8 T.ha−1 after one year and 28 T.ha−1 after two years were observed in the 3–20 cm layers, probably because the humification of grass root residues did not balance the decomposition of pre-existing SOM. Contrarily, after eight years of pasture, the initial OC content of surface soil had been almost entirely restored, including the 3–20 cm layer. Changes in the isotopic ratios 13C/12C of SOM were used to determine the respective contribution of OC derived from forest (Cf) and pasture (Cp) in each situation. After one year, the proportion of Cp was already 5% in the whole 0–20 cm layer. After two years, it was of 20%, whereas about 40% of Cf had disappeared. After eight years, the proportion of Cp was close to 40%, whereas almost no further decrease of Cf had been observed between two and eight years of permanent pasture.

São comparadas num mesmo latossolo podzólico amarelo de textura média, situações sob vegetação natural, depois da queimada, após um e cinco anos de cultivo e após três anos de pousio consecutivos a dois anos de cultivo. Depois da queimada e um ano de cultivo, há uma forte diminuição de todos os resíduos vegetais. Esta diminuição foi quantidade na liteira e na camada 0-15 cm do solo através do fracionamento granulométrico da matéria orgânica. Esta evolução continua durante os cinco anos de cultivo e se inverte quando o solo é abandonado à capoeira após dois anos de cultivo. O carbono da fração 0-50 μm, que concentra o complexo argilo-húmico, não sofre grandes variações quantitativas. O fracionamento químico desta fração mostra que, sob cultivo, o húmus é caracterizado por um equilíbrio, comportando mais ácidos fúlvicos, principalmente os extraídos pelo hidróxido de sódio, e menos ácidos húmicos do que no ecossistema natural. Isto indica que o húmus incorpora frações jovens pouco polimerizadas e que há, ao mesmo tempo, despolimerização das frações ligadas às argilas. O equilíbrio inicial se restabelece quando, depois de um curto período de cultivo, se deixa o solo em pousio. In an area of yellow podzolic latossol, five differents conditions of soil use, were compared: natural forest, recently, one and five years of annual crops, and three years of fallow following two years of annual crops. The organic matter was characterized by grain-size fractionation method. In the soils after burring and one year of cropping, plant residues in the litter and 0-15 em layer werw much less abundant than under the natural vegetation. Such evolution continued up to five years of cultivation, but was cultivation, but was reserved when the soil was abondoned and fallow developed. Carbon of the very fine fractiones (less than 50 μm), which concentrates the clay-humic complex material, remained almost unchanged. Chemical fractionation of this material shewed that under annual crops the humus composition changed, and the amount of fulvic acids, principally those soluble in sodium hydroxide, increased, contrary to the humic acid. This results suggest that hamus incorporated non-polymeric material from the crops, and that a de-polymerisation process of the pre-existing clay-humic complex material ocuured. This process stopped under fallow and the humus then returned to its initial equilibrium.

CADASIL is an increasingly recognized cause of stroke and dementia in humans. Neuropathological lesions include multiple deep infarcts, severe white matter lesions and diffuse alterations of the small cerebral arteries characterized by major alterations of vascular smooth muscle cells, which ultimately disappear. We recently established that CADASIL is due to mutations in the Notch3 gene.

From the surface horizon of an organic-rich mountain soil, humic and fulvic acids, and organo-mineral compounds including clay and hydroxy-metal colloids, were separated and purified. Each of these fractions was hydrolyzed in 3.0 M HCl under reflux, then the reaction parameters related to the solubilization of carbon and nitrogen and to the kinetics of hydrolysis were calculated. Acid hydrolysis was interpreted as the result of two successive steps: first a rapid electrophilic attack of heteroatomic C-O and C-N bonds by protons, then a slow nucleophilic hydration of the protonated bonds. Electron delocalization in these bonds, which increased with the polycondensation degree of organic compounds, and with their adsoprtion on mineral surfaces, resulted in an increase in their stability to hydrolysis. Fulvic acids were found to be the less stable material, and lead to predominantly anionic hydrolysis products. Clay-sized humin was the most stable material and yielded mainly cationic hydrolysates. The stability to hydrolysis and the humification degree of organic matter in the fractions generally coincided, and decreased in the following order: fine clay-sized humin > alkali dispersible organo-mineral colloids > > humic acids > hydroxy-ferric organic colloids > hydroxy-aluminium organic colloids = fulvic acids. Key words: Organo-mineral complex, humic substances, acid hydrolysis, carbon, nitrogen

The environmental aspects of the fate of anilines and related compounds are examined. They include the ecotoxicological aspects, the physico‐chemical and (bio)chemical reactions in the gas phase, aquatic environments, plants and soil. The particularity of this class of substances is the formation of “bound residues”; in high quantities, up to 95% in soil within one vegetation period. Some new results on the catalytically induced incorporation of anilines in soil organic matter are presented.

4-Chloroaniline reacted with catechol to form 4,5-bis(4-chlorophenylamino)3,5-cyclohexadiene-1,2-dione. The reaction was catalyzed mainly by tyrosinase or pyrolusit.

International audience; Root mucilage material (RM) was isolated from maize plants grown in the field, and its affinity to montmorillonite (M) homoionic to Pb2+ and Cd2+ was compared with that of a commercial polygalacturonic acid (PGA). Adsorption isotherms of the commercial and natural materials on the two clay systems were compared in unbuffered systems at pH 3 and pH 6. Adsorption of PGA occurred only at pH 3, and was higher on M-Pb than on M-Cd. In contrast, the adsorption of RM was higher on M-Cd than on M-Pb. Total amounts of RM adsorbed at pH 3 were about 3 times lower on M-Cd and 20 times lower on M-Pb than the respective amounts of PGA adsorbed at the same pH. Polygalacturonic acid had a high content of relatively well dissociated (pKa = 3.5) carboxylic groups, and adsorbed on the clay surface at pH values lower than its pKa. At pH 6, the dissociation of the acid groups favoured its solubility, and the metal cations were then probably displaced by ion exchange. The lower affinity of RM to the clay materials was related to its average molecular weight, which was lower than that of PGA, and to its water solubility, which was higher than that of PGA. The low pH dependence of the adsorption of RM was related to its lower carboxylic acidity and higher content in hydroxyl and amino groups.

International audience; A major concern in environmental studies is the estimation of the impact of anthropogenic activities on natural systems. Organic compounds are among the more abundant and the more various pollutants. Because they can display significant adsorption capacities and thus transport other (non organic) pollutants, they should be carefully analyzed. The oil industry has developed advanced organic geochemical techniques in order to improve knowledge of the structure and evolution of natural organic matter. Most of the advanced techniques that are required for the characterization of organic compounds can be directly used in environmental studies. Three major problems regarding organic pollutant impacts on the environment must be addressed: (i) the characterization of the source of the organic pollutants, (ii) their migration and dispersion in water, soils and sediments and (iii) their stability during degradation processes such as biodegradation, oxidation, etc. Those problems require an approach similar to that frequently used in the petroleum field. In petroleum exploration, it is important to characterize the source rocks for oil, to study its migration and dispersion in the reservoir rock and to estimate the changes induced by different alterations. The aim of this paper is to present applications of oil exploration analytical techniques to environmental problems.

Copper is a trace element of major concern for agricultural soils. It exhibits a high toxicity against microorganisms and is widely introduced into soils as a component of pesticide treatments or urban wastes such as sewage sludges or refuse composts. In most French vineyards, “Bordeaux mixture” (copper sulfate) has been applied for more than a century, sometimes leading to copper concentrations in soils much higher than the threshold values (100 mg kg−1 in France). Microorganisms exposed to high concentrations of copper or other trace elements are known to develop resistance mechanisms and represent a suitable material for the study of such processes, both at a physiological and molecular level (Capasso et al., 1996).

Interactions of organic matter with metallic cations in natural aqueous environments influence its transport by their participation in its “precipitation”. Flocculation of organic macromolecules is of importance in drinking water production, water recycling and waste water treatment. Metallic cations (alkaline-earth, Cu(II), etc.) act as flocculating ions for the organic matter in suspension in aqueous environments.