Crystallization and preliminary X-ray diffraction analysis of BipD, a virulence factor from Burkholderia pseudomallei

BipD is likely to be a component of a type-III protein secretion system (TTSS) in B. pseudomallei. Native and selenomethionyl-BipD proteins have been expressed and crystals have been obtained which diffract to 2.1 Å

Compact and accurate concept of laser wavemeters based on ellipsometry

Common laser wavemeters are based on a scanning Michelson interferometer. Displacements of the moving mirror as long as tens of centimeters are needed to reach a relative accuracy of 1 × 10−6 (1σ) on the unknown laser wavelengths. Such a long displacement range makes the system very sensitive to mechanical vibrations and to misalignments of the laser beams. The purpose of this paper is to demonstrate a new concept of laser wavemeter based on the measurements of the ellipsometric parameters ψ and of the laser beams. Experimental results show that a 10−6 (1σ) accuracy level could be reach with a displacement range of only 4 μm. Implementations of the device are described. Comparisons between our polarimetric wavemeter and a calibrated wavemeter are presented for two lasers, an extended cavity laser diode at 656 nm and a 532 nm green line Nd:YAG laser

The use of global rating scales for OSCEs in veterinary medicine

OSCEs (Objective Structured Clinical Examinations) are widely used in health professions to assess clinical skills competence. Raters use standardized binary checklists (CL) or multi-dimensional global rating scales (GRS) to score candidates performing specific tasks. This study assessed the reliability of CL and GRS scores in the assessment of veterinary students, and is the first study to demonstrate the reliability of GRS within veterinary medical education. Twelve raters from two different schools (6 from University of Calgary [UCVM] and 6 from Royal (Dick) School of Veterinary Studies [R(D)SVS] were asked to score 12 students (6 from each school). All raters assessed all students (video recordings) during 4 OSCE stations (bovine haltering, gowning and gloving, equine bandaging and skin suturing). Raters scored students using a CL, followed by the GRS. Novice raters (6 R(D)SVS) were assessed independently of expert raters (6 UCVM). Generalizability theory (G theory), analysis of variance (ANOVA) and t-tests were used to determine the reliability of rater scores, assess any between school differences (by student, by rater), and determine if there were differences between CL and GRS scores. There was no significant difference in rater performance with use of the CL or the GRS. Scores from the CL were significantly higher than scores from the GRS. The reliability of checklist scores were .42 and .76 for novice and expert raters respectively. The reliability of the global rating scale scores were .7 and .86 for novice and expert raters respectively. A decision study (D-study) showed that once trained using CL, GRS could be utilized to reliably score clinical skills in veterinary medicine with both novice and experienced raters

Feline low-grade alimentary lymphoma: an emerging entity and a potential animal model for human disease

BackgroundLow-grade alimentary lymphoma (LGAL) is characterised by the infiltration of neoplastic T-lymphocytes, typically in the small intestine. The incidence of LGAL has increased over the last ten years and it is now the most frequent digestive neoplasia in cats and comprises 60 to 75% of gastrointestinal lymphoma cases. Given that LGAL shares common clinical, paraclinical and ultrasonographic features with inflammatory bowel diseases, establishing a diagnosis is challenging. A review was designed to summarise current knowledge of the pathogenesis, diagnosis, prognosis and treatment of feline LGAL. Electronic searches of PubMed and Science Direct were carried out without date or language restrictions.ResultsA total of 176 peer-reviewed documents were identified and most of which were published in the last twenty years. 130 studies were found from the veterinary literature and 46 from the human medicine literature. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. The pathophysiology of feline LGAL still needs to be elucidated, not least the putative roles of infectious agents, environmental factors as well as genetic events. The most common therapeutic strategy is combination treatment with prednisolone and chlorambucil, and prolonged remission can often be achieved. Developments in immunohistochemical analysis and clonality testing have improved the confidence of clinicians in obtaining a correct diagnosis between LGAL and IBD. The condition shares similarities with some diseases in humans, especially human indolent T-cell lymphoproliferative disorder of the gastrointestinal tract.ConclusionsThe pathophysiology of feline LGAL still needs to be elucidated and prospective studies as well as standardisation of therapeutic strategies are needed. A combination of conventional histopathology and immunohistochemistry remains the current gold-standard test, but clinicians should be cautious about reclassifying cats previously diagnosed with IBD to lymphoma on the basis of clonality testing. Importantly, feline LGAL could be considered to be a potential animal model for indolent digestive T-cell lymphoproliferative disorder, a rare condition in human medicine

INVAPROM Espèce végétale invasive et production de matière organique dans une annexe de l'hydrosystème Loire

The purpose of the INVAPROM project is to measure the impact of Ludwigia grandiflora spp. hexapetala, an invasive plant species, on the production of organic matter in an oxbow lake of the Loire ecosystem. This has been poorly studied in large rivers. It focuses on two questions, the first (Q1), relating to the production of organic matter, aims to identify and quantify the production of organic matter from Ludwigia in situ. The hypothesis that Ludwigia biomass constitutes most of the organic matter (OM) in the owbow lake is our initial hypothesis. We also expected an accumulation of this MO. The second question deals with the function of degradation of organic matter by shredding invertebrate communities, also in situ. We assume that the degradation rate of OM and that the shredder invertebrate densities increase with the densities of Ludwigia.Le projet INVAPROM a pour objectif de mesurer l’impact des jussies appartenant à l’espèce Ludwigia grandiflora spp. hexapetala, espèce végétale invasive, sur la production de matière organique dans une annexe de l’hydrosystème Loire, ce qui a été peu étudié en grand cours d’eau. Il s’articule autour de deux questions, la première (Q1), relative à la production de matière organique, vise à identifier et quantifier la part des jussies dans la production de matière organique in situ. L’hypothèse selon laquelle la biomasse de jussies constitue la majeure partie de la matière organique (MO) au sein de l’annexe, est notre hypothèse de départ. Nous prévoyions également une accumulation de cette MO. La seconde question traite de la fonction de dégradation de la matière organique par les communautés d’invertébrés déchiqueteurs, également in situ. Nous supposons que le taux de dégradation de la MO et que les densités d’invertébrés déchiqueteurs augmentent avec les densités de jussies. La quantification de l’activité de dégradation de la matière organique par les invertébrés déchiqueteurs est faite en deux temps. L’expérience A a pour objectif de quantifier la dégradation des feuilles et tiges de l’année précédente (Q2A) tandis que l’expérience B a pour objectif de quantifier la dégradation des feuilles de l’année en cours (Q2B). Les expériences de production in situ ont montré que les quantités de nécromasses de L. grandiflora sont logiquement liées aux biomasses. La production de nécromasse est plus faible en ombrage nul qu’en ombrage fort. Dans cette condition, la nécromasse de feuilles d’arbres (230g dw .m-² en 6 mois) domine largement celle de L. grandiflora (35g dw .m-²). Sur la période d’étude, les quantités de L. grandiflora en ombrage nul (173g dw .m-²) sont quasi équivalentes à celles des arbres en ombrage fort. Au sein de l’annexe hydraulique, la présence de ce macrophyte allochtone entraine une certaine homogénéisation spatiale des dépôts de nécromasses. Afin de limiter les quantités de matière organique produites par ces macrophytes, des mesures de gestion visant à réduire la production par les macrophytes par un ombrage doivent être proposées. Notre hypothèse de départ se trouve validée dans les secteurs sans ombrage.Les feuilles de L. grandiflora ont une décomposition lente car le rapport C:N initial, de 17,5±0,7, est fort comparé à celui d’autres macrophytes (Royer and Minshall 1997). Le taux global de dégradation est faible tout au long de l’année, quelle que soit la densité de jussie, et en dépit des conditions du milieu, à caractère eutrophe, qui favorisent les communautés microbiennes assurant la décomposition (Royer and Minshall 1997). Au vu des conditions physico chimiques opérant dans l’annexe, deux processus agissant en synergie peuvent également ralentir les processus de dégradation. L’alimentation en eau se fait par une eau d’origine phréatique qui peut être désoxygénée. De même, les quantités importantes de matière organique peuvent entrainer des conditions anoxiques lors de leur décomposition qui peuvent inhiber l’activité des hyphomycètes (Bärlocher et al. 2008 ; Carpenter and Lodge 1986 ; Field and Webster 1983), voire réduire celles des invertébrés.Nous avions également supposé que les communautés de macro-invertébrés colonisant les feuilles de L. grandiflora fraichement tombées évoluaient au cours de la saison. Or celles-ci n’évoluent pratiquement pas, sont peu riches en taxons et ne consomment que faiblement la matière organique produite par les jussies. Cependant ces communautés d’invertébrés semblent jouer un rôle sur la vitesse de dégradation qui est un peu plus rapide en été. Les jussies constituent une nouvelle source de matière organique dans les annexes à laquelle les invertébrés ne seraient pas encore adaptés. De ce fait, la présence de L. grandiflora dans les annexes de la Loire moyenne contribue au stockage de la matière organique dans ces annexes où les processus d’atterrissement seront très probablement accélérés.Notre étude a également permis d’identifier la dynamique temporelle de fonctionnement hydraulique et physico-chimique de l’annexe hydraulique sur un cycle hydrologique contenant une longue phase de déconnexion suivie d’une séquence de connexions-déconnexions avec la Loire. L’analyse des paramètres non conservatifs, mesurés in situ avec un pas de temps horaire a permis de cerner le mode de fonctionnement de cet habitat. L’annexe est alimentée par une ou plusieurs nappes phréatiques à conductivité plus élevées que celle de la Loire. La production primaire y est très importante, celle-ci tend à épuiser les ressources en nitrates. La durée de la période de production biologique (microphytes et macrophytes) y est plus longue que dans le chenal principal. Les organismes vivant dans les mouilles de cette annexe sont soumis à des variations quotidiennes de dioxygène pouvant atteindre 100%, des périodes d’hypoxie et d’anoxie de plusieurs semaines. En phase de connexion, ils subissent des changements brutaux des conditions de pH, conductivité et de concentration en dioxygène

Detection and measurement of canine a-macroglobulins by enzyme immuno-assay

The α-macroglobulins are broad-specificity protease inhibitors important in the regulation and clearance from circulation of biologically active proteases. Inappropriate protease activation may be a feature of canine acute pancreatitis and the ability of the animal to clear these proteases may be important in determining survival. An enzyme immunoassay for the detection and measurement of canine α-macroglobulins in plasma samples was developed. A reference range for the canine α-macroglobulins of 1.20-2.72 mg ml was established from a panel of canine plasma samples, and the stability of the α-macroglobulins in plasma samples stored at 4°C was investigated. Changes in the level of the α-macroglobulins during disease states involving increased endogenous protease activity can now be investigated using a rapid, repeatable and quantifiable assay

Assessing the variability of colonisation by Water Primrose within an Atlantic marsh.

Assessing the variability of colonisation by Water Primrose within an Atlantic marsh.. 8. International Conference on the Ecology and Management of Alien Plant Invasion

Tumor necrosis factor-a at presentation in 60 cases of spontaneous canine acute pancreatitis

Tumor necrosis factor-α (TNF) is a pleiotropic cytokine with profound and broad ranging effects on many cell types. There have been few publications investigating the role of TNF in spontaneous disease processes of dogs, particularly the role of this cytokine during endotoxaemia, shock and multiple organ dysfunction syndromes. Plasma samples taken at presentation from 60 dogs with spontaneous acute pancreatitis of varying severity levels (scored 0–4 in ascending severity) were assessed for TNF activity by bioassay and total TNF protein levels through a dot-blot immunoassay. TNF activity by bioassay was detected in 31% (4/13) of dogs presenting with severe disease (>50% expected mortality) as defined using a scoring system for organ compromise, and was not detectable in the remaining animals or healthy controls. TNF activity was detected in 66% (4/6) animals in the highest severity group (Score 4), these animals were showing severe multiple organ dysfunction. Total TNF protein levels, measured by dot-blot immunoassay, exhibited a wide range in all severity groups and healthy dogs. Dogs with detectable TNF activity were not distinguished from the other severity or healthy groups by immunoassay. The absence of detectable differences in total TNF protein levels between the various severity groups suggests that other factors may be crucial in determining the role of TNF in spontaneous canine acute pancreatitis and subsequent endotoxaemia and shock

New simple optical sensor: from nanometer resolution to centimeter displacement range

A very simple displacement sensor is presented with nanometric resolution over centimetric travel range. The compact system is composed of a laser-diode module and a photodiode array leading to a non-contact sensor. With a corner cube configuration, it is not sensitive to most of main mechanical defects of the mobile platform. The use of an optical fiber and a normalization process inspired from classical fourquadrant detectors allows high repeatability and minimal drifts. This paper exposes the setup, simulations and experimental results. Several displacements over millimeters range with a resolution of 1.2 nm sustain the simulations