Evaluation of a spatialized agronomic model in predicting yield and N leaching at the scale of the Seine-Normandie Basin.

The EU directive has addressed ambitious targets concerning the quality of water bodies. Predicting water quality as affected by land use and management requires using dynamic agro-hydrogeological models. In this study, an agronomic model (STICS) and a hydrogeological model (MODCOU) have been associated in order to simulate nitrogen fluxes in the Seine-Normandie Basin, which is affected by nitrate pollution of groundwater due to intensive farming systems. This modeling platform was used to predict and understand the spatial and temporal evolution of water quality over the 1971-2013 period. A quality assurance protocol (Refsgaard et al. Environ Model Softw 20: 1201-1215, 2005) was used to qualify the reliability of STICS outputs. Four iterative runs of the model were carried out with improved parameterization of soils and crop management without any change in the model. Improving model inputs changed much more the spatial distribution of simulated N losses than their mean values. STICS slightly underestimated the crop yields compared to the observed values at the administrative district scale. The platform also slightly underestimated the nitrate concentration at the outlet level with a mean difference ranging from -1.4 to -9.2 mg NO3 L-1 according to the aquifer during the last decade. This outcome should help the stakeholders in decision-making to prevent nitrate pollution and provide new specifications for STICS development.

Dietary supplementation with pressurized whey in patients with cystic fibrosis.

Cystic fibrosis (CF) is characterized by malnutrition, chronic pulmonary inflammation, and oxidative stress. Whey protein is rich in sulfhydryl groups and is recognized for its ability to increase glutathione and reduce oxidative stress. Previously, we have shown that supplementation with whey increased intracellular glutathione levels in patients with CF. We have subsequently shown that hyperbaric pressure treatment of whey protein promotes the release of novel peptides for absorption, increases intracellular glutathione in healthy subjects, and reduces in vitro production of interleukin (IL)-8. We hypothesized that pressurized whey supplementation in children and adults with CF could have significant nutritional and anti-inflammatory benefits. A pilot open-label study of 1-month dietary supplementation with pressurized whey in CF patients was undertaken to assess the effects. Twenty-seven patients with CF (nine children, 18 adults) were enrolled. The dose of pressurized whey was 20 g/day in patients less than 18 years of age and 40 g/day in older patients. Anthropometric measures, pulmonary function, serum C-reactive protein (CRP), whole blood glutathione, and whole blood IL-8 and IL-6 responses to phytohemagglutinin (PHA) stimulation were measured at baseline and at 1 month. Three adults withdrew (one with gastrointestinal side effects, two with acute infection). Both children and adults showed enhancements in nutritional status, as assessed by body mass index. Children showed improvement in lung function (forced expiratory volume in 1 second). The majority of patients with an initially elevated CRP showed a decrease. PHA-stimulated IL-8 responses tended to decrease in the adults. Whole blood glutathione levels did not change. Thus, oral supplementation with pressurized whey improves nutritional status and can have additional beneficial effects on inflammation in patients with CF.

Long term prospective of the Seine River system: confronting climatic and direct anthropogenic changes.

To explore the evolution of a human impacted river, the Seine (France), over the 21st century, three driving factors were examined: climate, agriculture, and point source inputs of domestic and industrial origin. Three future scenarios were constructed, by modification of a baseline representative of recent conditions. A climate change scenario, based on simulations by a general circulation model driven by the SRES-A2 scenario of radiative forcing, accounts for an average warming of +3.3 degrees C over the watershed and marked winter increase and summer decrease in precipitation. To illustrate a possible reduction in nitrate pollution from agricultural origin, a scenario of good agricultural practices was considered, introducing catch crops and a 20% decrease in nitrogen fertilisation. Future point source pollution was estimated following the assumptions embedded in scenario SRES-A2 regarding demographic, economic and technologic changes, leading to reductions of 30 to 75% compared to 2000, depending on the pollutants. Four models, addressing separate components of the river system (agronomical model, hydrogeological model, land surface model and water quality model), were used to analyse the relative impact of these scenarios on water quality, in light of their impact on hydrology and crop production. The first-order driving factor of water quality over the 21st century is the projected reduction of point source pollution, inducing a noticeable decrease in eutrophication and oxygen deficits downstream from Paris. The impact of climate change on these terms is driven by the warming of the water column. It enhances algal growth in spring and the loss factors responsible for phytoplankton mortality in late summer (grazers and viruses). In contrast, increased seasonal contrasts in river discharge have a negligible impact on river water quality, as do the changes in riverine nitrate concentration, which never gets limiting. The latter changes have a similar magnitude under the three scenarios. Under climate change, riverine and groundwater nitrate concentrations increase and crop production is advantaged with reduced growing cycles and increased yields. In contrast, nitrate concentrations decrease under the good agricultural practices scenario, with a limited decrease in crop production. When these two scenarios are combined, the changes in nitrate concentrations balance each other and crop yields increase. The results of this numerical exercise indicate that the potential changes to the Seine River system during the 21st century will not lead to severely degraded water quality.

Interactions between abscisic acid and ethylene signaling cascades.

We screened for mutations that either enhanced or suppressed the abscisic acid (ABA)-resistant seed germination phenotype of the Arabidopsis abi1-1 mutant. Alleles of the constitutive ethylene response mutant ctr1 and ethylene-insensitive mutant ein2 were recovered as enhancer and suppressor mutations, respectively. Using these and other ethylene response mutants, we showed that the ethylene signaling cascade defined by the ETR1, CTR1, and EIN2 genes inhibits ABA signaling in seeds. Furthermore, epistasis analysis between ethylene- and ABA-insensitive mutations indicated that endogenous ethylene promotes seed germination by decreasing sensitivity to endogenous ABA. In marked contrast to the situation in seeds, ein2 and etr1-1 roots were resistant to both ABA and ethylene. Our data indicate that ABA inhibition of root growth requires a functional ethylene signaling cascade, although this inhibition is apparently not mediated by an increase in ethylene biosynthesis. These results are discussed in the context of the other hormonal regulations controlling seed germination and root growth.

ABI1 protein phosphatase 2C is a negative regulator of abscisic acid signaling.

The plant hormone abscisic acid (ABA) is a key regulator of seed maturation and germination and mediates adaptive responses to environmental stress. In Arabidopsis, the ABI1 gene encodes a member of the 2C class of protein serine/threonine phosphatases (PP2C), and the abi1-1 mutation markedly reduces ABA responsiveness in both seeds and vegetative tissues. However, this mutation is dominant and has been the only mutant allele available for the ABI1 gene. Hence, it remained unclear whether ABI1 contributes to ABA signaling, and in case ABI1 does regulate ABA responsiveness, whether it is a positive or negative regulator of ABA action. In this study, we isolated seven novel alleles of the ABI1 gene as intragenic revertants of the abi1-1 mutant. In contrast to the ABA-resistant abi1-1 mutant, these revertants were more sensitive than the wild type to the inhibition of seed germination and seedling root growth by applied ABA. They also displayed increases in seed dormancy and drought adaptive responses that are indicative of a higher responsiveness to endogenous ABA. The revertant alleles were recessive to the wild-type ABI1 allele in enhancing ABA sensitivity, indicating that this ABA-supersensitive phenotype results from a loss of function in ABI1. The seven suppressor mutations are missense mutations in conserved regions of the PP2C domain of ABI1, and each of the corresponding revertant alleles encodes an ABI1 protein that lacked any detectable PP2C activity in an in vitro enzymatic assay. These results indicate that a loss of ABI1 PP2C activity leads to an enhanced responsiveness to ABA. Thus, the wild-type ABI1 phosphatase is a negative regulator of ABA responses.

Developmental regulation of two tomato lipoxygenase promoters in transgenic tobacco and tomato.

Two lipoxygenase (LOX) genes (tomloxA and tomloxB) are expressed in ripening tomato fruit, and tomloxA is also expressed in germinating seedlings. The 5'-upstream regions of these genes were isolated to study the regulatory elements involved in coordinating tomlox gene expression. Sequence analysis of the promoters did not reveal any previously characterized regulatory elements except for TATA and CAAT boxes. However, the sequence motif GATAcAnnAAtnTGATG was found in both promoters. Chimeric gene fusions of each tomlox promoter with the beta-glucuronidase reporter gene (gus) were introduced into tobacco and tomato plants via Agrobacterium-mediated transformation. GUS activity in tomloxA-gus plants during seed germination peaked at day 5 and was enhanced by methyl jasmonate (MeJa) treatment. No GUS activity was detected in tomloxB-gus seedlings. Neither wounding nor abscisic acid (ABA) treatment of transgenic seedlings modified the activity of either promoter. During fruit development, GUS expression in tomloxA-gus tobacco fruit increased 5 days after anthesis (DAA) and peaked at 20 DAA. In tomloxB-gus tobacco fruit, GUS activity increased at 10 DAA and peaked at 20 DAA. In transgenic tomato fruit, tomloxA-gus expression was localized to the outer pericarp during fruit ripening, while tomloxB-gus expression was localized in the outer pericarp and columella. These data demonstrate that the promoter regions used in these experiments contain cis-acting regulatory elements required for proper regulation of tomlox expression during development and for MeJa-responsiveness.

Reversible inhibition of proton release activity and the anesthetic-induced acid-base equilibrium between the 480 and 570 nm forms of bacteriorhodopsin.

In purple membrane added with general anesthetics, there exists an acid-base equilibrium between two spectral forms of the pigment: bR570 and bR480 (apparent pKa = 7.3). As the purple 570 nm bacteriorhodopsin is reversibly transformed into its red 480 nm form, the proton pumping capability of the pigment reversibly decreases, as indicated by transient proton release measurements and proton translocation action spectra of mixture of both spectral forms. It happens in spite of a complete photochemical activity in bR480 that is mostly characterized by fast deprotonation and slow reprotonation steps and which, under continuous illumination, bleaches with a yield comparable to that of bR570. This modified photochemical activity has a correlated specific photoelectrical counterpart: a faster proton extrusion current and a slower reprotonation current. The relative areas of all photocurrent phases are reduced in bR480, most likely because its photochemistry is accompanied by charge movements for shorter distances than in the native pigment, reflecting a reversible inhibition of the pumping activity.

[Benign migratory glossitis: an enigmatic lesion]. / La glossite bénigne migratoire: une lésion énigmatique.

Although benign migratory glossitis, commonly called "geographic tongue," is frequently observed, we still have not been able to determine its etiology. While the condition is usually asymptomatic, the spectacular appearance of the lesion frequently causes the patient considerable worry. Based on a review of the literature, different theories on the lesion's etiology as well as therapeutic modalities will be discussed.

The cloning of two tomato lipoxygenase genes and their differential expression during fruit ripening.

A membrane-associated lipoxygenase from breaker-stage fruit of tomato (Lycopersicon esculentum Mill.) was purified and partially sequenced. Using degenerate oligonucleotides corresponding to portions of this sequence, a cDNA was amplified by PCR and used to screen a breaker fruit cDNA library. Two clones, tomloxA and tomloxB, were isolated and one of these (tomloxA) corresponded to the isolated protein. Genomic clones were isolated and sequence data from these were used to obtain the 5' ends of the cDNAs. The 2.8-kb cDNAs encode proteins that are similar in size and sequence to each other and to other plant lipoxygenases. DNA blot analysis indicated that tomato contains three or more genes that encode lipoxygenase. RNA blot analysis showed that tomloxA is expressed in germinating seeds as well as in ripening fruit, where it reached its peak during breaker stage. tomloxB appears to be fruit specific and is at its highest level in ripe fruit.

Overexpression of seleno-glutathione peroxidase by gene transfer enhances the resistance of T47D human breast cells to clastogenic oxidants.

The role of seleno-glutathione peroxidase (GSHPx; EC 1.11.1.9) in the cellular defense against oxidative stress was selectively investigated in novel cell models. Expression vectors designed to overexpress human GSHPx efficiently in a broad range of mammalian cells were used to transfect T47D human breast cells which contain very low levels of endogenous GSHPx. Several stable transfectants expressing GSHPx to various extents, up to 10-100 times more than parental cells, were isolated and characterized. Growth inhibition kinetics following transient exposure to increasing concentrations of H2O2, cumene hydroperoxide or menadione (an intracellular source of free radicals and reactive oxygen intermediates) showed that transfectants overexpressing GSHPx were considerably more resistant than control T47D cell derivatives to each of these oxidants. A sensitive DNA end-labeling procedure was used as a novel approach to compare relative extents of DNA strand breakage in these cells. In contrast to the extensive DNA damage induced in control transfectants by 1-h exposure to cytotoxic concentrations of menadione, the extent of DNA breakage detected in GSHPx-rich transfectants was remarkably reduced (6- to 9-fold, p less than 0.005).

Monitoring of blood levels of cyclosporine in renal and cardiac transplant recipients--comparison of HPLC to Incstar CYCLO-Trac SP RIA.

Cyclosporine in whole blood samples from renal and cardiac transplant recipients was measured by high-performance liquid chromatography (HPLC) and by CYCLO-Trac SP specific radioimmunoassay (RIA). The fresh samples assayed by RIA were remeasured in a second laboratory after storage at -20 degrees C for two to six months and good interlaboratory agreement was obtained on the 59 samples assayed (y = 0.926x + 14.8 micrograms/L, r = 0.982). The calibration curve for RIA was not influenced by fresh whole blood, hemolyzed whole blood or serum matrix from normal volunteers. However, comparison of the RIA results from patient samples with those from an HPLC procedure showed that RIA values averaged about double those measured by HPLC. The difference is attributable to differences between the blood matrix of transplant and nontransplant subjects, rather than exclusively to the apparent nonspecific nature of the antibody.

Isolation of cross-reacting compounds to Incstar Cyclo-Trac SP RIA in blood samples obtained from cardiac allograft patients on cyclosporine therapy.

To examine the specificity of the Incstar Cyclo-Trac SP RIA kit, individual blood samples from 28 cardiac allograft patients on cyclosporine A (CsA) therapy were extracted and chromatographed by HPLC. Initially, eluates from a pool of the above samples were collected at regular intervals and measured by RIA to locate possible cross-reacting compounds. Unknown cross-reacting materials were detected in a fraction (UNK) that was collected before elution of CsA. For each patient's sample, fraction UNK and the fraction containing CsA were then collected and measured by RIA. In 9 of 28 samples, cross-reactivity was detected in fraction UNK; range 11 to 36%, mean 22 +/- 7.5%. Cross-reactivity was not apparent in fraction UNK of CsA-free blood samples from normal volunteers.

Dissociation of authentic and artifactual effect of circulating heparin on drug protein binding.

The purpose of this study was to dissociate the authentic and artifactual effect of in vivo heparin on drug protein binding using protamine as an inhibitor of ex vivo lipolysis. A mixture of ethylenediamine tetra-acetic acid (EDTA, 5 mg ml-1) and protamine in the concentration range of 0 to 7.5 mg ml-1 was added to blood samples from 23 cardiac catheterized patients before (control) and 10 min after 3000 IU of intravenous heparin. In control samples, protamine does not interfere with the protein binding of lidocaine (L), quinidine (Q) or propranolol (P) when plasma pH is readjusted to 7.4. In the absence of protamine, heparin induced a significant increase in the free fraction by 40, 130, and 30 per cent for L, Q, and P, respectively (p less than 0.001), while free fatty acid (FFA) levels increased 2 to 6 fold. When protamine was present, the heparin-induced elevation in free fraction was significantly lower for L (16 per cent) and Q (77 per cent) but not for P; FFA levels were decreased at all protamine concentrations. Residual increases in free fraction and FFA levels compared to control values may represent the true in vivo effect of heparin at the peak activity of lipoprotein lipases. For L and Q, variations in free fraction were strongly associated with variations in FFA, but for P, no significant correlation was observed (r = 0.492). These results indicate that variations in free fraction of L and Q caused by heparin are, to a large extent, artifactual but may be prevented by use of protamine in collection tubes (5 to 7.5 mg ml-1). For P, the increase in free fraction was not mediated by variations of FFA indicating that another mechanism must be involved.

Determination of nalbuphine by high-performance liquid chromatography with electrochemical detection: application to clinical samples from postoperative patients.

A rapid, selective and reproducible high-performance liquid chromatographic assay with electrochemical detection was developed for the determination of nalbuphine in human plasma. The method involves extraction with chloroform-isopropanol at pH 9.4, back-extraction into dilute phosphoric acid and reversed-phase chromatography on a microBondapak phenyl column. The recovery of nalbuphine and naltrexone (internal standard) was greater than 90%. Calibration curves were linear over a concentration range of 3-36 ng/ml with coefficients of variation, within-day or between-day, not exceeding 8% at any level. Although the limit of detection was 0.3 ng/ml based on a signal-to-noise ratio of 3, the reliable limit of quantitation was 1 ng/ml (coefficient of variation 12%) using 1 ml of plasma. The dual-electrode detector was operated in the screening mode of oxidation (electrode 1, 0.3 V and electrode 2, 0.6 V), providing a greater specificity and reducing background noise. This procedure was applied to a large number of clinical samples in an intravenous dose-range pharmacokinetic study in patients.

Bioavailability of 11 quinidine formulations adn pharmacokinetic variation in humans.

The bioavailabilities of eight quinidine sulfate, two gluconate, and one polygalacturonate formulations were compared, with one of the sulfate formulations as a reference (R) in a panel of 24 volunteers, according to a design comprising duplicate 6 x 6 Latin squares in two subject groups. Only one gluconate formulation (H) gave a significantly lower (p less than 0.05) area under the curve from 0 to 30 hr (AUC30), 90% or R, which was not as significant as AUC infinity (94% of R). Formulation H also gave a significantly lower peak concentration (Cmax) and a longer time to peak concentration (tmax) and generally exhibited some characteristics of sustained-release product. In addition, one product (F) gave a significantly higher Cmax while another formulation (D) gave a longer tmax. The wide range of dissolution times obtained with these products with three test conditions was not reflected in the AUC, Cmax, or tmax values obtained, except the Formulation H was consistently the slowest to dissolve. The terminal rate constants, expressed as t 1/2, of the 24 subjects gave an overall mean of 7.49 +/- 0.77 hr and ranged from 6.24 +/- 0.28 to 0.49 +/- 0.90 hr in individuals. The estimated total body clearance, with the assumption that the oral bioavailability was 70%, gave an overall mean of 4.22 +/- 1.05 and ranged from 2.49 +/- 0.28 to 6.42 +/- 0.70 mg/min/kg in individuals, demonstrating the wide range of quinidine disposition even in healthy subjects; this finding is in agreement with recently published results.

The assay and absorption kinetics of oral theophylline-7-acetic acid in the human.

A sensitive and specific method for the estimation of theophylline-7-acetic acid in plasma by high performance liquid chromatography is described. Acidified plasma is extracted with chloroform-n-butanol (85: 15), back extracted with phosphate buffer (0.5 mmol-1, pH 6.5), and finally the acidified aqueous phase extracted again with chloroform-butanol. After evaporation of the extract the residue is redissolved in the chromatographic mobile phase (hexane-dichloromethane-ethanol-acetic acid, 10 : 86 : 3 : 1) and chromatographed on silica gel. The method was used to follow the plasma theophylline-7-acetic acid concentrations in two volunteers after single oral doses of 1.0 g of the drug. The results confirm previous reports, based on urine data and on plasma data following intravenous administration, that the drug is poorly absorbed (apparent bioavailability of 1 and 2 per cent), rapidly eliminated (half-life of 1.0 and 2.4 h) and not converted to theophylline.

The estimation of quinidine in human plasma by ion pair extraction and high-performance liquid chromatography.

A rapid, sensitive, accurate method for determination of quinidine in plasma has been developed using ion-pair extraction and high-performance liquid chromatography. The method, which is capable of distinguishing between quinidine and dihydroquinidine, involves acidification of plasma with perchloric acid, extraction with methyl isobutyl ketone and chromatography of the carbonate-washed extract on a silica gel column with a mobile phase of methylene chloride-hexane-methanol--perchloric acid (60:35:5.5:0.1) followed by fluorometric detection. The procedure is sensitive to below 50 ng/ml (coefficient of variation 6.6%) and compares favourably with a standard spectrofluorometric method when tested with plasma from volunteer subjects.

Bioavailability of three isoniazid formulations.

The bioavailability of three isoniazid formulations was assessed using a procedure specific for the free drug. Nine human volunteers, all slow acetylators, were each given 4 X 100 mg of isoniazid of three different tablet formulations at weekly intervals; the plasma drug levels were measured at different times during the first 24 hr. No significant differences (p greater than 0.05) were detected among the three products as to relative bioavailability, peak plasma concentrations, Cmax, and the time of Cmax, tmax. Analysis of variance of the pharmacokinetic parameters obtained according to a one-compartment open model did not demonstrate any significant formulation or time effect but revealed a significant intersubject variation in all parameters involved.