Comparison of effects of dexamethasone and the leukotriene D4 receptor antagonist L-708,738 on lung function and airway cytologic findings in horses with recurrent airway obstruction     

Lavoie JP  Léguillette R  Pasloske K  Charette L  Sawyer N  Guay D  Murphy T  Hickey GJ 《American journal of veterinary research》2002,63(4):579-585

OBJECTIVE: To evaluate whether the leukotriene (LT) D4 receptor antagonist L-708,738 is therapeutically beneficial in treating horses with recurrent airway obstruction (heaves). ANIMALS: 12 adult horses with heaves and healthy lung lobes from 20 slaughtered horses. PROCEDURE: Lung lobes were used for smooth muscle tension and radioligand binding studies. Horses with heaves were given a placebo for 14 days and administered L-708,738 (n = 6; 2.5 mg/kg PO, q 12 h) or dexamethasone (6; 0.04 mg/kg, IV, q 24 h) from days 14 to 28. Pulmonary function was measured weekly for 36 days, and bronchoalveolar cells were collected on days 0,14, and 29 for cytologic examination. RESULTS: Nanomolar concentrations of L-708,738 were effective at antagonizing LTD4-induced bronchoconstriction and LTD4-receptor binding in lung lobes. Mean peak and trough L708,738 plasma concentrations during the treatment period were 1.54 and 0.28 microM, respectively. On days 21 and 29, lung mechanics were significantly improved in the dexamethasone-treated horses but not in the L-708,738-treated horses. Neither dexamethasone nor L-708,738 had a significant effect on cytologic findings. CONCLUSIONS AND CLINICAL RELEVANCE: L-708,738 was bioavailable after oral administration and sustained concentrations in plasma during the dosing period that exceeded in vitro efficacy values. However, airway function did not improve, suggesting that either drug concentrations in the lungs were subtherapeutic or that cysteinyl LT may not be important mediators of airway inflammation in heaves. Results provide the first evidence of cysteinyl LT1 receptors in airways of horses.  相似文献   

Ancestrus dans un troupeau de trauies: etude clinico-pathologique.          下载免费PDF全文

G Renaud  P Guay  M Beauregard  A Leclerc    P Lamothe 《The Canadian veterinary journal. La revue veterinaire canadienne》1972,13(4):94-99

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A mathematical model of the effects of chronic carriers on the within-herd spread of contagious bovine pleuropneumonia in an African mixed crop-livestock system     

Lesnoff M  Laval G  Bonnet P  Chalvet-Monfray K  Lancelot R  Thiaucourt F 《Preventive veterinary medicine》2004,62(2):101-117

Contagious bovine pleuropneumonia (CBPP) is a respiratory disease of cattle; CBPP is caused by Mycoplasma mycoides subsp. mycoides small colony. CBPP is a major cause for concern for African countries (because of mortality, animal-production losses and cost of control). The clinical form of the disease is the more infectious (contagion occurs essentially through coughing). However, chronic lung lesions with viable mycoplasmas can persist in recovering cattle. Animals presenting these lesions might have a time-delimitated infectious phase. Such carriers are suspected to generate field outbreaks (although this hypothesis remains debated). We investigated the potential quantitative effects of these chronic carriers on the within-herd CBPP spread. Data were collected during a longitudinal field herd survey in a mixed crop-livestock system in the Ethiopian highlands. Two stochastic Markov-chain models' outputs (seroconversion dynamics, basic reproduction ratio R0, cumulative clinical incidence and risk of herd infection) were compared given different hypotheses on the carrier infectiousness. The late seroconversions observed in the field data were fitted correctly only for the highest carrier infectiousness we considered (mean chronic duration of 1 year and carriers 50-times less infectious than clinical cases). Although sensitivities (in terms of disease impact in the herd) were in general negligible when the carrier infectiousness was low (e.g. when carriers were assumed to be 1000-times less infectious than clinical cases), they rapidly became important when the infectiousness increased.  相似文献   

Diagnostic potential of natriuretic peptides in the occult phase of golden retriever muscular dystrophy cardiomyopathy     

Chetboul V  Tessier-Vetzel D  Escriou C  Tissier R  Carlos C  Boussouf M  Pouchelon JL  Blot S  Derumeaux G 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2004,18(6):845-850

The objective of the study was to determine whether the plasma concentrations of atrial and brain natriuretic peptides (ANP and BNP, respectively) could be reliable markers of cardiac alterations during occult cardiomyopathy in Golden Retriever Muscular Dystrophy (GRMD). Fifty Golden Retrievers without any clinical or radiographic sign of heart disease were included in this study (21 GRMD dogs and 29 controls). Controls and GRMD dogs were divided into 2 subgroups according to age (< and > or =12 months old, respectively). All dogs underwent echocardiography and determination of BNP and ANP plasma concentrations by radioimmunoassay. No ventricular dilatation or dysfunction was observed in either control or GRMD dogs. ANP plasma concentration did not differ significantly between controls and GRMD dogs (mean +/- SD = 72 +/- 49 versus 58 +/- 23 pg/mL, respectively, P = .21). This finding was confirmed in both subgroups of dogs (ie, those < and > or =12 months old). In contrast, BNP plasma concentrations were significantly higher in GRMD dogs than in controls (mean +/- SD = 117 +/- 92 versus 46 +/- 22 pg/mL, respectively, P < .05). In dogs > or =12 months old, sensitivity and specificity of BNP for identifying GRMD with a cutoff of 65 pg/mL were 78 and 86%, respectively. For the same cutoff value, sensitivity dropped to 42%, whereas specificity reached 100% in dogs <12 months old. In conclusion, BNP may be a useful biochemical marker of asymptomatic cardiomyopathy. However, this peptide does not allow very early detection because its optimal discriminatory power was observed in adult dogs (ie, > or =12 months of age).  相似文献   

Usefulness of single copy genes containing introns in Phytophthora for the development of detection tools for the regulated species P. ramorum and P. fragariae     

Renaud Ioos  Lise Laugustin  Nathalie Schenck  Sylvie Rose  Claude Husson  Pascal Frey 《European journal of plant pathology / European Foundation for Plant Pathology》2006,116(2):171-176

Introns are generally highly polymorphic regions within genes and were proven to be of great interest for discriminating among phylogenetically-close Phytophthora species. Phytophthora ramorum and P. fragariae are considered as quarantine pathogens by the European Union and accurate detection tools are therefore necessary for their monitoring. From introns located in different single copy genes (GPA1, RAS-like, and TRP1), we developed a series of PCR primers specific to P. ramorum and P. fragariae. The specificity of these primers was successfully checked with a wide collection of Phytophthora isolates and a protocol was developed to detect both pathogens directly in infected plant tissues. These genes should be of particular interest for the development of additional species-specific detection tools within the Phytophthora genus.  相似文献   

Chemistry. A light touch catalyzes asymmetric carbon-carbon bond formation     

Renaud P  Leong P 《Science (New York, N.Y.)》2008,322(5898):55-56

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Extraction of DNA from soil   总被引：1，自引：0，他引：1  

Patrick Robe  Renaud Nalin  Carmela Capellano  Timothy M. Vogel  Pascal Simonet 《European Journal of Soil Biology》2003,39(4):183-190

There is an increased interest in the extraction of nucleic acids from various environmental samples, since molecular techniques allow less biased access to a greater portion of uncultivable microorganisms. Two strategies have been developed to improve DNA recovery in terms of yield, purity and unbiased representation of the microbial diversity. The first approach consists of the direct extraction of nucleic acids from soil through in situ cell lysis followed by DNA purification. The alternative approach is based on the separation of bacteria from the soil particles followed by cell lysis and then DNA purification. Several published methods describe the recovery of highly purified nucleic acids that are well-suited for molecular purposes even though a new challenge concerns the recovery of large bacterial DNAs essential for functional investigation of gene clusters and biosynthetic pathways. This review presents an overview of the available methods to achieve this challenging objective.  相似文献   

Chalara fraxinea is an invasive pathogen in France     

Claude Husson  Bruno Scala  Olivier Ca?l  Pascal Frey  Nicolas Feau  Renaud Ioos  Beno?t Mar?ais 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(3):311-324

Decline induced by Chalara fraxinea is an emerging disease that severely affects ash stands in Europe. The disease appears to have an invasive spread from East to West of Europe in the last decade. The teleomorphic stage, Hymenoscyphus pseudoalbidus, that occurs as apothecia on ash rachis in the litter was recently described. The origin of ash decline remains unclear as a cryptic species, H. albidus, a long-established fungus in Europe, could be present in the same niche, and as in Switzerland, H. pseudoalbidus was shown to have been present long before the recent epidemic outbreak. In France, the emerging disease is very recent and clearly restrained to Northeastern France. We thus collected isolates from infected hosts and from apothecia/ash rachis both inside and outside the infected area in France in order to compare them on the basis of pathogenicity towards ash seedlings and sequences of the ITS regions and of three single-copy genes. We showed that two population types exhibiting about 2% base pair polymorphism in the sequences analysed were present in Northern France. The first type, corresponding to H. pseudoalbidus, was present on rachis and infected hosts only in Northeastern France and showed strong pathogenicity towards ash seedlings in inoculation tests. By contrast, the second type, which corresponds to H. albidus, was present throughout Northern France and showed no pathogenicity towards ash seedlings. Our study confirms the results of Queloz et al. (2010) who presented molecular evidences for the existence of two cryptic species, H. albidus and H. pseudoalbidus. The results strongly suggest that Chalara fraxinea/H. pseudoalbidus is a recent invader in France.  相似文献   

Influence of microflora and composition of root bathing solution on root exudation of maize plants     

Virginie Groleau‐Renaud  Sylvain Plantureux  Ashraf Tubeileh  Armand Guckert 《Journal of plant nutrition》2013,36(9):1283-1301

Root exudation of carbon (C) plays a major role in processes occurring in the plant rhizosphere. Environmental factors affecting root exudation have been identified but their effects are rarely quantified. The purpose of this work was to evaluate the impact of both the microflora and the chemical composition of the growth medium on root exudation, taking into account soluble exudates and mucilage fraction. Maize plants (Zea mays L.) were grown for 12 days in hydroponic conditions and then transferred in three root bathing solutions (demineralized water, KCl or nutrient solution) during 24 hours. In each case, presence of microflora was tested with a comparison between plants inoculated with maize rhizospheric strain and axenic plants. Exudation was measured in terms of C and biomass production. A strong interaction was noticed between microflora and chemical composition of the root bathing solution. In fact, the presence of rhizospheric microflora induces a stimulation of soluble exudates only in KCl and Nutrient solutions. In demineralized water, a different response was observed with a higher C release for axenic plants, probably due to the osmotic shock induced to the roots. Concerning mucilage fractions, small quantities were recovered on all treatments. This work demonstrates that the chemical composition of the root bathing solution and presence of microorganisms significantly modify the amount of soluble exudates. Attention must therefore be paid to the cultural conditions when exudation is studied because of the sensitivity of this process to root environment.  相似文献   

Assessing the effects of subtropical forest fragmentation on leaf nitrogen distribution using remote sensing data     

Moses Azong Cho  Abel Ramoelo  Pravesh Debba  Onisimo Mutanga  Renaud Mathieu  Heidi van Deventer  Nomzamo Ndlovu 《Landscape Ecology》2013,28(8):1479-1491

Subtropical forest loss resulting from conversion of forest to other land-cover types such as grassland, secondary forest, subsistence crop farms and small forest patches affects leaf nitrogen (N) stocks in the landscape. This study explores the utility of new remote sensing tools to model the spatial distribution of leaf N concentration in a forested landscape undergoing deforestation in KwaZulu-Natal, South Africa. Leaf N was mapped using models developed from RapidEye imagery; a relatively new space-borne multispectral sensor. RapidEye consists of five spectral bands in the visible to near infra-red (NIR) and has a spatial resolution of 5 m. MERIS terrestrial chlorophyll index derived from the RapidEye explained 50 % of the variance in leaf N across different land-cover types with a model standard error of prediction of 29 % (i.e. of the observed mean leaf N) when assessed on an independent test data. The results showed that indigenous forest fragmentation leads to significant losses in leaf N as most of the land-cover types (e.g. grasslands and subsistence farmlands) resulting from forest degradation showed lower leaf N when compared to the original indigenous forest. Further analysis of the spatial variation of leaf N revealed an autocorrelation distance of about 50 m for leaf N in the fragmented landscape, a scale corresponding to the average dimension of subsistence fields (2,781 m²) in the region. The availability of new multispectral sensors such as RapidEye thus, moves remote sensing closer to widespread monitoring of the effect of tropical forest degradation on leaf N distribution.  相似文献