Syndromes auto-inflammatoires en dermatologie [Autoinflammatory syndromes in dermatology].

Hereditary periodic fever syndromes, also called autoinflammatory syndromes, are characterized by relapsing fever and additional manifestations such as skin rashes, mucosal manifestations, or arthralgias. Some of these disorders present without fever but with the associated systemic manifestations. The responsible mutated genes have been identified for most of these disorders, which lead to the induction of the uncontrolled and excessive production of interleukin-1beta (IL-1beta). The inhibition of IL-1beta through IL-1 receptor antagonist or monoclonal antibody against IL-1beta is used with success in most of these diseases. In case of TNF-receptor associated periodic syndrome (TRAPS) and paediatric granulomatous arthritis (PGA), TNF-antagonists may also be used; in familial Mediterranean fever (FMF) colchicine remains the first choice.

Characterization of a specific 20- to 25-kD interleukin-1 inhibitor from cultured human lung macrophages.

Alveolar macrophages have the ability to downregulate immune processes in vitro. We have recently suggested the presence of interleukin-1 (IL-1) inhibitors in the supernatants of human bronchoalveolar lavage cells from patients with idiopathic pulmonary fibrosis or sarcoidosis. In the present study, we further analyze the cellular origin and the biologic properties of a 20- to 25-kD IL-1 inhibitor spontaneously produced by cultured human alveolar macrophages (AM). The inhibitor blocks IL-1-induced prostaglandin E2 production by human fibroblasts and the IL-1-related increase of phytohemagglutinin-induced murine thymocyte proliferation. After rigorous IL-1 alpha and IL-1 beta depletion, supernatants of lung macrophages specifically block the binding of IL-1 to its receptor on the murine thymoma cell line EL4-6.1 in a dose-dependent manner. These results indicate that AM from both normal donors and patients produce a specific IL-1 inhibitor that may be of importance in protecting the alveolar environment from the deleterious effects of excessive IL-1 production.

Characterization of the role of Rho activating signalling complexes in G protein-coupled receptor induced cardiac fibrosis

Dans certaines conditions pathologiques, telles que l'hypertension artérielle ou l'infarctus du myocarde, le coeur répond à une augmentation de la post-charge par des processus de remodelage aboutissant à une hypertrophie du ventricule gauche. L'hypertrophie cardiaque est caractérisée par une croissance hypertrophique des cardiomyocytes, ainsi que par une différenciation des fibroblastes en un phenotype présentant une capacité accrue de synthèse protéiques, nommés myofibroblastes. Ceci résulte en une accumulation excessive des constituants de la matrice extracellulaire, ou autrement dit fibrose. En raison de son effet délétère sur la contractilité du coeur, menant sur le long terme à une insuffisance cardiaque, de nombreux efforts ont été déployés, afin de définir les mécanismes moléculaires impliqués dans la réponse profibrotique. A ce jour, de nombreuses études indiquent que la petite GTPase RhoA pourrait être un médiateur important de la réponse profibrotique du myocarde. Cependant, les facteurs d'échanges impliqués dans la transduction de signaux profibrotiques, via la régulation de son activité au niveau des fibroblastes cardiaques, n'ont pas encore été identifiés. De précédentes études menées dans le laboratoire, ont identifiées une nouvelle protein d'ancrage de la PKA, exprimée majoritairement dans le coeur, nommée AKAP-Lbc. Il a été montré que cette protéine, en plus de sa fonction de protein d'ancrage, possédait une activité de facteur d'échange de nucléotide guanine (GEF) pour la petite GTPase RhoA. Au niveau des cardiomyocytes, il a été montré que l'AKAP-Lbc participe à une voie de signalisation pro-hypertrophique, incluant la sous-unité alpha de la protéine G hétérotrimerique G12 et RhoA. Chose intéressante, des observations antérieures à cette étude, indiquent que dans le coeur, l'AKAP-Lbc est également exprimée dans les fibroblastes. Cependant aucunes études n'a encore reporté de fonction pour ce facteur d'échange dans les fibroblastes cardiaques. Dans ce travail, les résultats obtenus indiquent que dans les fibroblastes cardiaques, I'activation de RhoA par l'AKAP-Lbc est impliquée dans la transmission de signaux profibrotiques, en aval des récépteurs à l'angiotensine II. En particulier, nous avons observé que la suppression de l'expression de l'AKAP-Lbc dans les fibroblastes ventriculaires de rat adultes, réduisait fortement Γ activation de Rho induite par l'angiotensine II, la déposition de collagène, la capacité migratoire des fibroblastes ainsi que leur différenciation en myofibroblastes. A notre connaissance, l'AKAP-Lbc est le premier RhoGEF identifié comme médiateur de la réponse profibrotique dans les fibroblastes cardiaques. - In pathological conditions such as chronic hypertension or myocardial infarction, the myocardium is subjected to various biomechanical and biochemical stresses, and undergoes an adverse ventricular remodelling process associated with cardiomyocytes hypertrophy and excess deposition of extracellular matrix proteins resulting in fibrosis. During the fibrotic response, cardiac fibroblasts differentiate into a more mobile and contractile phenotype termed myofibroblasts. These cells, possess a greater synthetic ability to produce ECM proteins and have been implicated in diseases with increased ECM deposition including cardiac fibrosis. Because fibrosis impairs myocardial contractility and is associated with the progression to heart failure, a major cause of lethality worldwide, many efforts have been made to define the molecular players involved in this process. During these last years, increasing evidence suggests a role for the small GTPase RhoA in mediating the fibrotic response in CFbs. However the identity of the exchange factors that modulate its activity and transduce fibrotic signals in CFbs is still unknown. Earlier work in our laboratory identified a novel PKA anchoring protein expressed in the heart termed AKAP-Lbc that has been shown to function as anchoring protein as well as a guanine nucleotide exchange factor (GEF) for the small GTPase RhoA. In response to several hypertrophic stimuli we have shown that RhoGEF activity of AKAP-Lbc mediated by Gan promotes the activation of a signaling pathway including RhoA, leading to cardiomyocytes hypertrophy. Within the heart, previous observations made in the laboratory indicated that AKAP-Lbc was also expressed in fibroblasts. However its role in cardiac fibroblasts remained to be determined. In the present study, we show that AKAP-Lbc is critical for activating RhoA and transducing profibrotic signals downstream of angiotensin II receptors in cardiac fibroblasts. In particular, our results indicate that suppression of AKAP-Lbc expression by infecting adult rat ventricular fibroblasts with lentiviruses encoding AKAP-Lbc specific short hairpin RNAs strongly reduces angiotensin II-induced RhoA activation, collagen deposition as well as cell migration and differentiation. These findings identify AKAP-Lbc as the first Rho-guanine nucleotide exchange factor involved in a profibrotic signalling pathway at the level of cardiac fibroblasts.

15N uptake fom manure and fertilizer sources by three consecutive crops under controlled conditions

There are several regions of the world where soil N analysis and/or N budgets are not used to determine how much N to apply, resulting in higher than needed N inputs, especially when manure is used. One such region is the North Central "La Comarca Lagunera", one of the most important dairy production areas of Mexico. We conducted a unique controlled greenhouse study using 15N fertilizer and 15N isotopic-labeled manure that was labeled under local conditions to monitor N cycling and recovery under higher N inputs. The manure-N treatment was applied only once and was incorporated in the soil before planting the first forage crop at an equivalent rate of 30, 60 and 120 Mg ha-1 dry manure. The 15N treatments were equivalent to 120 and 240 kg ha-1 (NH4)2SO4-N for each crop. The total N fertilizer for each N fertilized treatment were 360, and 720 kg ha-1 N. We found very low N recoveries: about 9 % from the manure N inputs, lower than the 22 to 25 % from the fertilizer N inputs. The manure N recovered belowground in soil and roots ranged from 82 to 88 %. The low recoveries of N by the aboveground and low soil inorganic nitrate (NO3-N) and ammonium (NH4-N) content after the third harvested suggested that most of the 15N recovered belowground was in the soil organic form. The losses from manure N inputs ranged from 3 to 11 %, lower than the 34 to 39 % lost from fertilizer N sources. Our study shows that excessive applications of manure or fertilizer N that are traditionally used in this region will not increase the rate of N uptake by aboveground compartment but will increase the potential for N losses to the environment.

Association between white-coat effect and blunted dipping of nocturnal blood pressure.

In this study, we assessed whether the white-coat effect (difference between office and daytime blood pressure (BP)) is associated with nondipping (absence of BP decrease at night). Data were available in 371 individuals of African descent from 74 families selected from a population-based hypertension register in the Seychelles Islands and in 295 Caucasian individuals randomly selected from a population-based study in Switzerland. We used standard multiple linear regression in the Swiss data and generalized estimating equations to account for familial correlations in the Seychelles data. The prevalence of systolic and diastolic nondipping (<10% nocturnal BP decrease) and white-coat hypertension (WCH) was respectively 51, 46, and 4% in blacks and 33, 37, and 7% in whites. When white coat effect and nocturnal dipping were taken as continuous variables (mm Hg), systolic (SBP) and diastolic BP (DBP) dipping were associated inversely and independently with white-coat effect (P < 0.05) in both populations. Analogously, the difference between office and daytime heart rate was inversely associated with the difference between daytime and night-time heart rate in the two populations. These results did not change after adjustment for potential confounders. The white-coat effect is associated with BP nondipping. The similar associations between office-daytime values and daytime-night-time values for both BP and heart rate suggest that the sympathetic nervous system might play a role. Our findings also further stress the interest, for clinicians, of assessing the presence of a white-coat effect as a means to further identify patients at increased cardiovascular risk and guide treatment accordingly.

Positional therapy for obstructive sleep apnea: an objective measurement of patients' usage and efficacy at home.

BACKGROUND: Positional therapy that prevents patients from sleeping supine has been used for many years to manage positional obstructive sleep apnea (OSA). However, patients' usage at home and the long term efficacy of this therapy have never been objectively assessed.¦METHODS: Sixteen patients with positional OSA who refused or could not tolerate continuous positive airway pressure (CPAP) were enrolled after a test night study (T0) to test the efficacy of the positional therapy device. The patients who had a successful test night were instructed to use the device every night for three months. Nightly usage was monitored by an actigraphic recorder placed inside the positional device. A follow-up night study (T3) was performed after three months of positional therapy.¦RESULTS: Patients used the device on average 73.7 ± 29.3% (mean ± SD) of the nights for 8.0 ± 2.0 h/night. 10/16 patients used the device more than 80% of the nights. Compared to the baseline (diagnostic) night, mean apnea-hypopnea index (AHI) decreased from 26.7 ± 17.5 to 6.0 ± 3.4 with the positional device (p<0.0001) during T0 night. Oxygen desaturation (3%) index also fell from 18.4 ± 11.1 to 7.1 ± 5.7 (p = 0.001). Time spent supine fell from 42.8 ± 26.2% to 5.8 ± 7.2% (p < 0.0001). At three months (T3), the benefits persisted with no difference in AHI (p = 0.58) or in time spent supine (p = 0.98) compared to T0 night. The Epworth sleepiness scale showed a significant decrease from 9.4 ± 4.5 to 6.6 ± 4.7 (p = 0.02) after three months.¦CONCLUSIONS: Selected patients with positional OSA can be effectively treated by a positional therapy with an objective compliance of 73.7% of the nights and a persistent efficacy after three months.

The daily energy expenditure in stable chronic obstructive pulmonary disease.

Resting energy expenditure is frequently increased in chronic obstructive pulmonary disease (COPD), but it is unknown if this hypermetabolism holds true over 24 h. The aim of this study was to measure the actual 24-h energy expenditure (24-h EE) in patients with stable COPD. Energy expenditure was measured by indirect calorimetry, using a metabolic chamber for 24-h EE and a canopy for basal metabolic rate (BMR). Physical activity was detected in the chamber by a radar system, and its duration was quantified. Two groups matched for age and height were studied: 16 male ambulatory patients with stable COPD and 12 male normal subjects. Body weight was 92 +/- 12% of ideal body weight in the group with COPD and 108 +/- 11% in the control group (p = 0.01). BMR was 120 +/- 7% of predicted in the group with COPD and 108 +/- 12% in the control group (p < 0.01). However, 24-h EE was similar in the two groups, amounting to 1,935 +/- 259 kcal in patients with COPD and 2,046 +/- 253 kcal in the control group (NS). This corresponded to 145% and 137% of predicted BMR, and to 121% and 126% of measured BMR in patients with COPD and the control group, respectively (NS). Patients were allowed to pursue their usual treatment within the chamber, and a positive correlation existed between 24-h EE and the daily dose of inhaled beta 2-agonists (p < 0.03). During daytime, physical activity was lower in patients with COPD. This study shows that patients with stable COPD are characterized by a normal daily energy expenditure in controlled conditions in spite of an increased basal metabolic rate. They appear to save energy by reducing their spontaneous level of physical activity.

Pre-pregnancy and pregnancy predictors of obesity.

Obesity has progressively become a global epidemic that constitutes one of the biggest current health problems worldwide. Pregnancy is a risk factor for excessive weight gain. Factors that may predict development of obesity in later life mainly include gestational weight gain, pre-pregnancy nutritional status, age, parity and race. Change in lifestyle factors, such as eating habits, enrollment in physical activity, smoking and duration of lactation, in addition to the above factors, may also contribute to the development of obesity but are still not fully understood. Women who retain more body weight after pregnancy have, in general, larger pregnancy body weight gain, higher pre-pregnancy body mass index, marked weight changes in previous pregnancies, lactate slightly less and stop smoking during pregnancy to a larger extent. In addition, irregular eating habits and decreased leisure time activity after delivery influence postpartum weight retention. Taking into consideration the epidemic of obesity, with all its adverse long-term consequences, there is an increasing need to promote counseling before, during and after pregnancy on the role of diet and physical activity in reproductive health.

Recovery of degraded pasture in Rondônia: macronutrients and productivity of brachiaria brizantha

Pasture is the main form of land use in Amazonia. Over time the pasture grass loses vigor and yields decrease, indicating a certain degree of degeneration. The main causes of degradation are lack of pasture maintenance and subsequent weed infestation, the choice of regionally unsuitable forage species and excessive grazing. The main purpose of this study was to evaluate the impact of different recovery managements on soil chemical properties and grass yield of a degraded pasture in Rondônia. For this purpose, an experiment was installed in October 2001, consisting of five treatments: C = control; HA = harrowing + NPK + micronutrients; HE = Herbicide + NK + micronutrients; R = No-tillage rice + NPK + micronutrients; and S = No-tillage soybean + PK + micronutrients. The following N, P and K sources were used: ammonium sulfate for N, calcined phosphate for P and potassium chloride for K. The experiment was arranged in a randomized block design with four replications. The shoot dry matter yield of the grass was analyzed as of the 35th month of experimentation, in a dry and a rainy period. Phosphorus fertilization resulted in significant increases in Ca2+ and Mg2+ and increasing trend of P in the topsoil in the initial months of the experiment in treatments HA and S and increases in Ca2+ and P (trend) in the treatment R. The cumulative production of Brachiaria brizantha, from Sep/2004 to Mar/2005, was 30,025, 28,267 and 27,735 kg ha-1 shoot dry matter in the treatments HA, R and S, respectively. These values differed significantly from treatments C and HE, with 17,040 and 17,057 kg ha-1, respectively. It was concluded that phosphorus fertilization associated to pasture reform was effective to raise the dry matter yield of Brachiaria brizantha. Rice or soybean under no-tillage is recommended as a practice of pasture recovery, due to the residual effect of fertilization.

Sleep disorders in boys with Duchenne muscular dystrophy

Introduction La dystrophie musculaire de Duchenne (DMD) est une myopathie progressive liée au chromosome X qui atteint environ un garçon sur 3500. Des troubles du sommeil (TDS) sont fréquemment rapportés par ces patients Les études effectuées à ce jour se sont essentiellement concentrées sur les troubles respiratoires liés au sommeil. Les TDS débutent toutefois fréquemment avant l'installation d'un trouble ventilatoire nocturne et de nombreux autres facteurs peuvent en être la cause. Objectif L'objectif de cette étude est d'évaluer la fréquence des TDS chez les garçons avec une DMD et d'en identifier les facteurs de risque. Méthode II s'agit d'une étude transversale effectuée par questionnaire postal adressé aux parents de tout garçon âgé de 4-18 ans avec une DMD, suivi dans deux centres tertiaires de réhabilitation pédiatrique (Lausanne et Dublin). Les TDS sont évalués à l'aide de la 'Sleep Disturbance Scale for Children' (SDSC), validée sur 1157 enfants sains. Elle permet d'obtenir un score total et des scores pour six facteurs représentant les TDS les plus fréquents (troubles de l'endormissement et du maintien du sommeil (TEMS), éveil nocturne-cauchemars, transition veille-sommeil, somnolence diurne excessive, troubles respiratoires associés au sommeil (TRS), hyperhidrose du sommeil). Un T- score supérieur à 70 (>2DS) est considéré comme pathologique. Les associations potentielles entre des scores pathologiques et des facteurs individuels (âge, mobilité diurne et nocturne, douleur), thérapeutiques (orthèses nocturnes, ventilation non-invasive, médication) et environnementaux (facteurs socio-familiaux) sont évaluées à l'aide d'analyses univariées (χ2) et de régressions logistiques ascendantes. Résultats Seize garçons sur 63, soit 25.4%, présentent un score total pathologique en comparaison au 3% attendus dans la population générale. Les TEMS (29.7%), les TRS (15.6%) et l'hyperhidrose du sommeil (14.3%) sont les TDS les plus prévalent. Le besoin d'être mobilisé la nuit par un tiers (OR=9.4; 95%CI: 2.2-40.7; p=0.003) et être l'enfant d'une famille monoparentale (OR=7.2; 95%CI: 1.5-35.1; p=0.015) sont des facteurs de risque indépendants pour un score total pathologique. Le besoin d'être mobilisé la nuit par un tiers (OR=18.0; 95%CI: 2.9¬110.6; p=0.002), le traitement par corticostéroïdes (OR=7.7; 95%CI: 1.4-44.0; p-0.021) et être l'enfant d'une famille monoparentale (OR=7.0; 95%CI: 1.3-38.4; p=0.025) sont des facteurs de risque indépendants pour un TEMS. Discussion Cette étude montre une prévalence élevée des TDS chez les garçons avec une DMD (25% contre 3% attendus dans la population générale). Le besoin d'être mobilisé la nuit par un tiers est identifié comme un facteur de risque important pour un score total pathologique et un TEMS. Il reflète vraisemblablement un degré d'atteinte motrice tel qu'il limite les mouvements spontanés et les adaptations posturales du sommeil, ayant pour conséquence une diminution importante de la qualité du sommeil. Les enfants vivant dans un foyer monoparental présentent plus fréquemment un score total pathologique et des TEMS, possiblement en lien avec un stress psychologique plus important dans ces familles. Le traitement par corticostéroïdes est identifié comme facteur de risque pour un TEMS. Une adaptation du schéma ou du dosage permet généralement de limiter cet effet secondaire. Si nécessaire, un traitement par Mélatonine peut être instauré. Aucune association n'a pu être mise en évidence entre les facteurs analysés et les TRS, possiblement en raison du petit nombre de garçons ayant rapporté de tels symptômes et du fait que certains symptômes d'hypoventilation nocturne ne sont pas évalués par la SDSC. Par ailleurs, la valeur prédictive de l'anamnèse, comme celle des fonctions pulmonaires diurnes, est connue pour être limitée, raison pour laquelle une oxy-capnométrie est effectuée de routine en dessous d'une capacité vitale forcée de 50%. Elle permet, si nécessaire, l'instauration précoce d'une ventilation non-invasive, limitant ainsi vraisemblablement l'impact de ('hypoventilation nocturne sur la qualité du sommeil dans notre population. Plusieurs limitations sont à évoquer. Le petit nombre de patients ne permet pas d'exclure d'autres associations potentielles. La nature transversale de l'étude augmente le risque de causalité inverse. Cette étude n'inclut pas de mesure quantitative du sommeil. Les questionnaires adressés aux parents ont toutefois pu être démontrés comme fiables hormis pour les TRS. Un biais de non-réponse ne peut pas être totalement exclu, bien que le taux de réponse soit élevé (86,5%) et qu'il n'y ait pas de différence significative entre les populations de répondeurs et non-répondeurs. Conclusion La prévalence des TDS est élevée chez les garçons avec une DMD et leurs causes sont multiples. Les facteurs de risques sont physiques (immobilité nocturne), pharmacologiques (corticothérapie) et environnementaux (famille monoparentale). Compte tenu de son impact sur la qualité de vie, l'évaluation du sommeil doit être systématique en consultation et ne pas se limiter aux seuls troubles ventilatoires nocturnes.

Plac8 is an inducer of C/EBPβ required for brown fat differentiation, thermoregulation, and control of body weight.

Brown adipocytes oxidize fatty acids to produce heat in response to cold or to excessive energy intake; stimulation of brown fat development and function may thus counteract obesity. Brown adipogenesis requires activation of the transcription factor C/EBPβ and recruitment of the zinc finger protein Prdm16, but upstream inducers of these proteins are incompletely defined. Here, we show that genetic inactivation of Plac8, a gene encoding an evolutionarily conserved protein, induces cold intolerance, and late-onset obesity, as well as abnormal morphology and impaired function of brown adipocytes. Using brown preadipocyte lines we show that Plac8 is required for brown fat differentiation, that its overexpression induces C/EBPβ and Prdm16, and that upon induction of differentiation Plac8 associates with C/EBPβ and binds to the C/EBPβ promoter to induce its transcription. Thus, Plac8 is a critical upstream regulator of brown fat differentiation and function that acts, at least in part, by inducing C/EBPβ expression.

Role of peroxynitrite in the redox regulation of cell signal transduction pathways.

Peroxynitrite is a potent oxidant and nitrating species formed from the reaction between the free radicals nitric oxide and superoxide. An excessive formation of peroxynitrite represents an important mechanism contributing to cell death and dysfunction in multiple cardiovascular pathologies, such as myocardial infarction, heart failure and atherosclerosis. Whereas initial works focused on direct oxidative biomolecular damage as the main route of peroxynitrite toxicity, more recent evidence, mainly obtained in vitro, indicates that peroxynitrite also behaves as a potent modulator of various cell signal transduction pathways. Due to its ability to nitrate tyrosine residues, peroxynitrite affects cellular processes dependent on tyrosine phosphorylation. Peroxynitrite also exerts complex effects on the activity of various kinases and phosphatases, resulting in the up- or downregulation of signalling cascades, in a concentration- and cell-dependent manner. Such roles of peroxynitrite in the redox regulation of key signalling pathways for cardiovascular homeostasis, including protein kinase B and C, the MAP kinases, Nuclear Factor Kappa B, as well as signalling dependent on insulin and the sympatho-adrenergic system are presented in detail in this review.

The characteristics of gait in Charcot-Marie-Tooth disease types I and II.

Certain typical gait characteristics such as foot-drop and foot supination are well described in Charcot-Marie-Tooth disease. These are directly related to the primary disease and due to the weakness of ankle dorsiflexors and everters characteristic of this hereditary neuropathy. We analysed 16 subjects aged 8-52 years old (11 with type I, 5 with type II Charcot-Marie-Tooth disease) using three-dimensional gait analysis and identified kinematic features previously unreported. These patients showed a combination of tight tendo achillei, foot-drop, failure of plantar flexion and increased foot supination, but also presented with excessive internal rotation of the knee and/or tibia, knee hyperextension in stance, excessive external rotation at the hips and decreased hip adduction in stance (typical of a broad based gait). These proximal features could have been an adaptation to or consequence of the disrupted ankle and foot biomechanics, however a direct relation to the neuropathy is also possible since sub-normal muscle power was observed at the proximal levels in most subjects on both manual testing and kinetic analysis. Gait analysis is a useful tool in defining the characteristic gait of patients with Charcot-Marie-Tooth disease.

Accumulation of phosphorus fractions and contamination potential in vineyard soils in the southern region of the state of Santa Catarina, Brazil

In vineyards, if phosphate is applied both before planting and at intervals during growth without consideration of technical criteria, the soil P fractions may be increased and their proportions altered. This study was carried out to evaluate the accumulation of P fractions and the parameters of the adsorption isotherm in a sandy Typic Hapludalf soil in vineyards with a history of successive and excessive phosphate fertilization. In December 2010, two vineyards were selected, one 4 and the other 15 years old, in Urussanga, State of Santa Catarina (Brazil). Three trenches were dug in each area and soil was collected from the 0-5, 5-10 and 10-20 cm depth ranges. The soil samples were dried in a forced-air oven, sieved and subjected to chemical analyses, P chemical fractionation and P adsorption isotherms. Excessive phosphate fertilization, before and during cultivation, particularly in the older vineyard and, consequently, with a longer history of phosphate fertilization, increased the inorganic P concentrations to the depth of 20 cm, especially in labile fractions extracted by anion exchange resin and NaHCO3 in the non-labile fraction, as well as in the non-labile fraction extracted by 1.0 mol L-1 HCl. The application of phosphate fertilizers and the long cultivation period increased the P levels in the organic labile fraction extracted by 0.5 mol L-1 NaHCO3, and especially in the moderately labile fraction extracted by 0.1 and 0.5 mol L-1 NaOH. Phosphate fertilization of older vineyards, i.e., cultivated for 15 years, increased the amounts of P desorbed in water, indicating a risk of contamination of surface waters and groundwater. The phosphate fertilization before planting, without considering the results of soil analysis, and during cultivation, disregarding the results of soil analysis, leaf analysis and expected yield, led to a reduction in the maximum P adsorption capacity in the 0-5 cm layer of vineyard 2, indicating saturation of part of the reactive particle adsorption sites.

Physical quality of an Oxisol after different periods of management systems

Management systems may lead to a loss of soil physical quality as a result of removal of the plant cover and excessive agricultural mechanization. The hypothesis of this study was that the soil aggregate stability, bulk density, macro- and microporosity, and the S index and saturated hydraulic conductivity may be used as indicators of the soil physical quality. The aim was to study the effects of different periods and managements on the physical attributes of a medium-textured Red Oxisol under soybean and corn for two growing seasons, and determine which layers are most susceptible to variations. A completely randomized experimental design was used with split plots (five treatments and four layers), with four replications. The treatments in 2008/09 consisted of: five years of no-tillage (NTS5), seven years of no-tillage (NTS7), nine years of no-tillage (NTS9), conventional tillage (CTS) and an adjacent area of native forest (NF). The treatments were extended for another year, identified in 2009/10 as: NTS6, NTS8, NTS10, CTS and NF. The soil layers 0-0.05, 0.05-0.10, 0.10-0.20 and 0.20-0.30 m were sampled. The highest S index values were observed in the treatment CTS in the 0-0.05 m layer (0.106) and the 0.05-0.10 m layer (0.099) in 2008/09, and in the 0-0.05 m layer (0.066) in 2009/10. This fact may be associated with soil turnover, resulting in high macroporosity in this treatment. In contrast, in the NTS, limiting macroporosity values were observed in some layers (below 0.10 m³ m-3). Highest aggregate stability as well as the highest saturated hydraulic conductivity (Kθ) values were observed in NF in relation to the other treatments. In 2009/10, the Kθ in NF differed only from NTS10. This study showed that the use of the S index alone cannot be recommended as an absolute indicator of the soil physical quality, even at values greater than 0.035.