Validation of the Medonic CA620/530 Vet 20-ml microcapillary sampler system for hematology testing of feline blood

The aim of the current study was to compare feline hematologic variables in blood collected in microcapillary tubes (20 ml) and conventional blood tubes with the Medonic CA620/530 Vet in-house hematologic analyzer. A comparison of results obtained in 60 cats presented at the clinics of the veterinary school showed that the correlations between the 2 methods were 0.97 for white blood cell, 0.95 for red blood cell, and 0.93 for platelet counts; 0.92 for hemoglobin concentration; and 0.99 for mean corpuscular volume. No clinically relevant differences between the 2 blood sampling techniques were observed for any variable, which suggests that both techniques are interchangeable in cats. Moreover, microcapillary tubes would allow easier repeated sampling in the same cat and would likely be useful in other small species

Non Magnetic Impurities in the Spin-Gap Phase of the Cuprate

It is now well established that Zn doping of high-$T_C$ cuprates reduces their $T_C$ and triggers the appearence of a spin glass phase. In this context, we have solved exactly the problem of N non magnetic impurities in the staggered flux phase of the Heisenberg model which we assume to be a good mean-field approximation for the spin-gap phase of the cuprates. In this model, the quasiparticule spectrum has four nodes on the Fermi surface, and linearization of the spectrum in the neighbourhood of these nodes leads to a system of 2D Dirac fermions. In the presence of a macroscopic number of (non magnetic) impurities, the problem has a characteristic logarithmic structure that renders ineffective the usual perturbative expansions. We have used this logarithmic structure to calculate an exact solution. For a concentration ni of impurities in the unitary scattering limit, the additional density of states is found to be proportional to $ni/(w \ln^2 (|w|/D))$ (where D is the infrared cut-off of the linearized spectrum) in analogy with the 1D case of doped spin-Peierls and two-leg ladders compounds. We argue that the system exhibits a quasi long-range order at T=0 with instantaneous spin-spin correlations decreasing as $ni/ \ln^4 (ni/R_{ij})$ for large distances $R_{ij}$ between impurity sites. We predict enhanced low energy fluctuations and compare these results to NMR and inelastic neutron scattering experiments in the high-$T_C$ cuprates.Comment: proceeding of SCES98 conference in Paris, July '9

Immunohistochimie des lymphomes gastrointestinaux du chat

Chez le chat, les lymphomes sont les tumeurs les plus fréquentes du tractus digestif. La seule étude morphologique par l’examen cytologique et/ou histopathologique ne permet pas dans tous les cas de différencier un lymphome d’une lésion hyperplasique ou réactionnelle et elle n’autorise pas non plus le typage des tumeurs qui nécessite l’identification précise de la sous-population cellulaire à l’origine de la prolifération néoplasique. Actuellement, au moyen d’un nombre limité d’anticorps utilisables sur des prélèvements fixés par le formol et inclus en paraffine, c’est-à-dire dans les conditions de la pratique clinique courante, le recours à des techniques immunohistochimiques permet d’accroitre de manière sensible les informations obtenues par l’examen histologique pratiquées sur des biopsies, aussi bien pour le typage des tumeurs que pour le diagnostic différentiel des lésions non tumorales. Les principes, modalités, indications et limites de ce type de méthodes appliquées à la gastroentérologie du chat sont présentés dans cette synthèse

Pharmacokinetics and pharmacodynamics of a therapeutic dose of unfractionated heparin (200 U/kg) administered subcutaneously or intravenously to healthy dogs

Objectives: To evaluate the effects of 200 U/kg of sodium unfractionated heparin (UFH) on coagulation times in dogs after IV and SC administration and to compare these effects with plasma heparin concentrations assessed by its anti Xa activity. Methods: 200 U/kg of UFH were administered Intravenously (IV) and Subcutaneously (SC) to five healthy adult Beagle dogs with a wash out period of at least 3 days. Activated Partial Thromboplastin Time (APTT), Prothrombin Time (PT) and plasma anti-factor Xa (aXa) activity were determined in serial blood samples. Results: After IV injection, PT remained unchanged except for a slight increase in one dog; APTT was not measurable (> 60 s) for 45 to 90 min, then decreased regularly and returned to baseline values between 150 and 240 min. High plasma heparin concentrations were observed (C max = 4.64±1.4 aXa U/mL) and decreased according to a slightly concave-convex pattern on a semi-logarithmic curve but returned to baseline slightly more slowly (t240 to t300 min). After SC administration, APTT was moderately prolonged (mean±SD prolongation: 1.55±0.28 x APTT t0, range [1.35-2.01]) between 1 and 4 hours after administration. Plasma anti-factor Xa activity reached a maximum of 0.56±0.20 aXa U/mL, range: [0.42 - 0.9] after 132±26.8 min and this lasted for 102±26.8 min. Heparin concentrations were grossly correlated to APTT; prolongation of APTT of 120 to 160% corresponded to plasma heparin concentrations range of 0.3-0.7 aXa U/mL, considered as the therapeutic range in human medicine. Conclusions: As in human, pharmacokinetic of UFH in dogs is non linear. Administration of 200 U/kg of UFH SC in healthy dogs results in sustained plasma heparin concentrations in accordance with human recommendations for thrombosis treatment or prevention, without excessively increased bleeding risks. In these conditions, APTT can be used as a surrogate to assess plasma heparin concentrations. This has to be confirmed in diseased animals

Order from Disorder: Non Magnetic Impurities in the Spin-gap Phase of the Cuprates

We solve the problem of $N$ non magnetic impurities in the staggered flux phase of the Heisenberg model which we assume to be a good mean-field approximation for the spin-gap phase of the cuprates. The density of states is evaluated exactly in the unitary limit and is porportional to 1/\left (\omega \ln^2(|\omega|/D)), in analogy with the 1D case of doped spin-Peierls and two-leg ladders compounds. We argue that the system exhibits a quasi long-range order at T=0 with instantaneous spin-spin correlations decreasing as n_i/ \ln^2\left (n_i R_{ij}) for large distances $R_{ij}$ and we predict enhanced low energy fluctuations in Neutron Scattering.Comment: 4 pages, corrected typos, references adde

A phylogenetic framework of the legume genus Aeschynomene for comparative genetic analysis of the Nod-dependent and Nod-independent symbioses

Background : Among semi-aquatic species of the legume genus Aeschynomene, some have the property of being nodulated by photosynthetic Bradyrhizobium lacking the nodABC genes necessary for the synthesis of Nod factors. Knowledge of the specificities underlying this Nod-independent symbiosis has been gained from the model legume Aeschynomene evenia but our understanding remains limited due to the lack of comparative genetics with related taxa using a Nod factor-dependent process. To fill this gap, we combined different approaches to perform a thorough comparative analysis in the genus Aeschynomene. Results: This study significantly broadened previous taxon sampling, including in allied genera, in order to construct a comprehensive phylogeny. In the phylogenetic tree, five main lineages were delineated, including a novel lineage, the Nod-independent clade and another one containing a polytomy that comprised several Aeschynomene groups and all the allied genera. This phylogeny was matched with data on chromosome number, genome size and low-copy nuclear gene sequences to reveal the diploid species and a polytomy containing mostly polyploid taxa. For these taxa, a single allopolyploid origin was inferred and the putative parental lineages were identified. Finally, nodulation tests with different Bradyrhizobium strains revealed new nodulation behaviours and the diploid species outside of the Nod-independent clade were compared for their experimental tractability and genetic diversity. Conclusions: The extended knowledge of the genetics and biology of the different lineages sheds new light of the evolutionary history of the genus Aeschynomene and they provide a solid framework to exploit efficiently the diversity encountered in Aeschynomene legumes. Notably, our backbone tree contains all the species that are diploid and it clarifies the genetic relationships between the Nod-independent clade and the Nod-dependent lineages. This study enabled the identification of A. americana and A. patula as the most suitable species to undertake a comparative genetic study of the Nod-independent and Nod-dependent symbioses

Les animaux grandissent / [textes, Catherine Bourges, Christine Coutaller, Odette Dénommée... et al.]

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Quantitative Structure Property Relationships (QSPR) for the adsorption of organic compounds onto activated carbon cloths. Comparison between multiple linear regression and neural network

International audienceQuantitative structure-property relationship (QSPR) for the adsorption of organic compounds onto activated carbon cloth: Comparison between multiple linear regression and neural network By: Brasquet, C; Bourges, B; Le Cloirec, P ENVIRONMENTAL SCIENCE & TECHNOLOGY Volume: 33 Issue: 23 Pages: 4226-4231 Published: DEC 1 1999 Context Sensitive Links Close AbstractClose Abstract The adsorption of 55 organic compounds is carried out onto a recently discovered adsorbent, activated carbon cloth. Isotherms are modeled using the Freundlich classical model, and the large database generated allows qualitative assumptions about the adsorption mechanism. However, to confirm these assumptions, a quantitative structure-property relationship methodology is used to assess the correlation between an adsorbability parameter (expressed using the Freundlich parameter K) and topological indices related to the compounds molecular structure (molecular connectivity indices, MCI). This correlation is set up by mean of two different statistical tools, multiple linear regression (MLR) and neural network (NN). A principal component analysis is carried out to generate new and uncorrelated variables. It enables the relations between the MCI to be analyzed, but the multiple linear regression assessed using the principal components (PCs) has a poor statistical quality and introduces high order PCs, too inaccurate for an explanation of the adsorption mechanism. The correlations are thus set up using the original variables (MCI), and both statistical teals, multiple linear regression and neural network, are compared from a descriptive and predictive point of view. To compare the predictive ability of both methods, a test database of 10 organic compounds is used. Results show the good descriptive ability of NN compared with that of MLR, with more than 68% variance explained by NN, whereas MLR allows only 44% variance explanation. However, the predictive ability of NN seems to be low, especially when the structure of the test compounds is not well described in the training database. The good descriptive ability of NN is then exploited to carry out a variable analysis using the Garson weight partitioning method and to give information about the adsorption process. This study shows that fiat molecules seem to be better adsorbed onto activated carbon fibers than bulky molecules, because of an adsorption which is located between the micrographitic planes of fibers. The adsorption process occurs via an electron donor-acceptor interaction between the surface of the activated carbon fiber(donor) and the solute (acceptor). Consequently, the aromatic compounds with electron-withdrawing substituents seem to be favored. Furthermore, the lower the solute affinity for the aqueous media, the greater seems to be the adsorption

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