Evaluation expérimentale de la fonction pulmonaire chez le porc

This synthesis aims to review the pulmonary function tests available in swine. Two techniques are used in order to measure the variations of the mechanical properties of the respiratory system. The oesophageal balloon remains the most used technique in order to determine these properties in pigs. However, it requires a systematic anaesthesia of the animal. The impulse oscillometry specifically measures the mechanical properties of the respiratory system, by a non invasive way, but the animals have to be trained to be immobilized or sedated to perform the measurement. The whole body arometric plethysmography allows measuring the respiratory pattern in unsedated freely moving piglets. That method allows investigating pigs for long term studies while minimizing the stress related to handling. From this point of view, it represents the less stressing technique for pigs. Finally, blood gases analysis is the easiest method to use in the field. It permits to assess respiratory function by measuring pH and blood partial pressures in oxygen and carbon dioxidePeer reviewe

Les protéines de choc thermique (heat shock proteins). I : Classification, structure, fonctions et implications dans les processus pathologiques

All living systems have evolved mechanisms to maintain homeostasis in the face of rapid environmental changes. When exposed to elevated temperatures, most of the cells activate the synthesis of a specific group of proteins called Heat Shock Proteins (Hsps). This heat shock response, under control of specific transcription factors, the Heat Shock factors (HSF), is an evolutionarily conserved mechanism, from bacteria to humans. Heat Shock Proteins are classified into families according to their molecular weight (Hsp 25, 40, 70, 90, 105). They play the role of molecular chaperones by binding and protecting other molecules (proteins, RNAs). The function of Hsp is to prevent accumulation of non-native proteins either by assisting proper folding of polypeptides or by driving them to proteosome pathway for degradation. Hsps are involved in various pathological processes that are accompanied by protein alterations such as chronic or degenerative diseases. This review describes structural and functional characteristics of the six main Hsps classes. It also focuses on their respective role in highly studied pathologies. The diversity of Hsps implications in these diseases explains that they became recently a strategic target in development of new therapeutic strategies.Tout organisme est doté de mécanismes lui permettant de résister à de brusques changements de son environnement. Exposées à une température anormalement élevée, la plupart des cellules activent l’expression d’une classe particulière de protéines appelées les protéines de choc thermique (Heat Shock Proteins, Hsps). Cette réponse cellulaire au choc thermique placée sous le contrôle de facteurs de trans-cription spécifiques, les facteurs de choc thermique (Heat shock factor, HSF) est un mécanisme conservé au travers de l’évolution depuis les bactéries jusqu’à l’homme. Les protéines de choc thermique qui sont divisées en familles désignées par leur masse moléculaire (Hsp25, 40, 70, 90, 105) font partie des molé-cules chaperons qui s’associent à d’autres molécules (protéines, ARNs) et en protègent la destinée. Le rôle des Hsp est d’empêcher l’accumulation de protéines anormales en aidant à conformer correctement les polypeptides ou en les dirigeant vers le protéosome qui les détruit. En tant que chaperons, les Hsp sont impliquées dans de nombreux processus pathologiques qui s’accompagnent d’altérations des protéines comme les maladies chroniques et dégénératives. Cette revue décrit les spécificités structurelles et fonc-tionnelles des six familles principales d'Hsp ainsi que leur intervention à différents niveaux dans les patho-logies les mieux étudiées. La multiplicité de l'implication des Hsp dans ces phénomènes pathologiques les désigne comme cibles privilégiées dans le développement de nouvelles stratégies thérapeutiques

In Vitro Inhibitory Effect of SR 27417, a Potent Platelet-Activating Factor (PAF) Receptor Antagonist, on the PAF-Induced Bovine Platelet Aggregation

The in vitro inhibitory effect of SR 27417, an antagonist of the platelet-activating factor (PAF) receptor, on PAF-induced platelet aggregation was studied in blood collected from seven healthy Friesien calves. Inhibitory effects of SR 27417 were determined at thirteen different concentrations (0.1-400 nM) by using the dose-response curves of PAF on calf platelet aggregation. In the presence of SR 27417, the maximal slopes of aggregation (%/min) induced by low and high concentrations of PAF were significantly different from the control values obtained without an antagonist at p < or = 0.05 and p < or = 0.01 respectively. In vitro PAF-induced calf platelet aggregation was dose-dependently inhibited by SR 27417. The drug inhibited PAF-induced platelet aggregation in a competitive reversible manner (pA2 = 10.46 +/- 2.36 mol x L(-1)). In conclusion, the results of our study showed that addition of SR 27417 to bovine platelet in vitro inhibits PAF-induced platelet aggregation.Effet inhibiteur in vitro du SR 27417, un puissant antagoniste du récepteur du facteur d'activation plaquettaire sur l'agrégation des plaquettes induite par le PAF chez le bovin. L'effet inhibiteur in vitro du SR 27417, un antagoniste du récepteur du facteur d'activation plaquettaire (PAF) induite par le PAF sur l'agrégation plaquettaire a été étudiée dans le sang prélevé des sept veaux sains de race Frisonne. L'effet inhibiteur du SR 27417 a été déterminé avec treize concentrations différentes (0,1 - 400 nM) en utilisant les courbes dose-effet du PAF sur l'agrégation plaquettaire des veaux. En présence du SR 27417, la pente d'agrégation maximale de la courbe ( concentrations du PAF ont été significativement différentes des valeurs de base ( et respectivement). L'agrégation des plaquettes induites par le PAF a été inhibée in vitro par le SR 27417 d'une manière dépendante de la dose. Le médicament a inhibé in vitro l'agrégation induite par le PAF des plaquettes chez le bovin de façon compétitive et réversible (pA2 = 10.46 2.36 molL-1). En conclusion, les résultats de notre étude montrent in vitro que l'addition du SR 27417 aux plaquettes chez le bovin inhibe l'agrégation plaquettaire induite par le PAF.Peer reviewe

Description d'une nouvelle intervention éducative pour développer les compétences en recherche chez les étudiants en médecine : ressenti des apprenants

International audienceContexte : Les programmes d'enseignement médical de premier cycle devraient renforcer le développement des compétences de recherche.But : Définir le ressenti d'une intervention éducative, basée sur trois sessions de 180 minutes, visant à améliorer, chez les étudiants, les compétences nécessaires à la rédaction d'un projet de recherche.Méthodes : L'intervention pédagogique a été conçue selon la procédure d'apprentissage en équipe (Team Based Learning (TBL)). Toutefois, le travail était partagé entre les différents groupes dont les ressources respectives ont été mises en commun pour produire un projet de recherche unique et original. Des enquêtes ont permis d'évaluer le niveau de satisfaction des étudiants. Résultats et conclusions : La formation est globalement très appréciée par les étudiants et leur est utile pour leurs futurs stages de recherche. Cette approche pourrait permettre de développer les compétences en recherche, y compris lorsque le temps disponible pour l'intervention éducative est limit

Pathophysiological changes occurring during Escherichia coli endotoxin and Pasteurella multocida challenge in piglets: relationship with cough and temperature and predicitive value for intensity of lesions.

The aims of this study were (1) to correlate cough and body temperature (BT) with the severity of bronchopneumonia in pigs, (2) to determine whether these clinical signs can be used to early diagnose bronchopneumonia and (3) to assess the predictive values of cough and BT regarding lung lesions. Bronchopneumonia was induced by administering E. coli endotoxin (LPS) combined with Pasteurella multocida type A (PmA) in the trachea of 13 piglets. Saline-instilled negative controls (n = 8), PmA inoculated (n = 6) and LPS instilled (n = 5) groups were also constituted. Cough and BT were recorded daily while the bronchopneumonia severity was assessed using bronchoalveolar lavage fluid (BALF) cytology, cytokines and measurement of lung lesion volume. Changes in expiratory breathing pattern were also measured (Penh). The combination of LPS and PmA induced a subacute bronchopneumonia characterised by macrophage, neutrophil, and lymphocyte infiltration, changes in Penh and an increase in the mRNA level of IFN-gamma while IL8, IL-18 and TNF-alpha mRNA levels remained unchanged. The daily body weight gain of infected animals was significantly reduced. Cough and BT changes were proportional to the intensity of the lung inflammatory process, functional respiratory changes and to the extent of macroscopic lesions. When comparing the individual values of cough and BT to thresholds defined for both parameters, an early diagnosis of pneumonia was possible. Considering the pooled data of each group, it was possible to define thresholds allowing an early segregation between the groups of diseased and healthy piglets. The daily values of cough and BT were predictive for the volume of lung lesions recorded at the end of the trial. In conclusion, cough and BT appear as potential indicators for the intensity and the evolution of the respiratory disease. They also seem to be good predictors for the magnitude of lung lesions and weight gain recorded at the study endpoint

Acer pseudoplatanus

Cette fiche résume les éléments essentiels relatifs à l'intoxication à l'érable sycomore (Acer pseudoplatanus

Correction: A lineage-specific rapid diagnostic test (Chagas Sero K-SeT) identifies Brazilian Trypanosoma cruzi II/V/VI reservoir hosts among diverse mammalian orders.

[This corrects the article DOI: 10.1371/journal.pone.0227828.]

A lineage-specific rapid diagnostic test (Chagas Sero K-SeT) identifies Brazilian Trypanosoma cruzi II/V/VI reservoir hosts among diverse mammalian orders.

Trypanosoma cruzi, the protozoan agent of Chagas disease in the Americas, is comprised of six genetic lineages (TcI-TcVI) and a possible seventh (TcBat, related to TcI). Identification of T. cruzi lineages infecting reservoir mammalian species is fundamental to resolving transmission cycles. However, this is hindered by the limited sensitivity and technical complexity of parasite isolation and genotyping. An alternative approach is serology using T. cruzi lineage-specific epitopes, such as those of the trypomastigote small surface antigen (TSSA). For surveillance of T. cruzi lineage infections in mammal species from diverse Brazilian regions, we apply a novel rapid diagnostic test (RDT, Chagas Sero K-SeT), which incorporates the TSSA peptide epitope specific to TcII/V/VI (TSSApep-II/V/VI) and Protein G detection of antibodies. Chagas Sero K-SeT RDT results with sera from experimentally infected mice, from tamarin primates (Leontopithecus spp.) and from canines (Canis familiaris) were concordant with corresponding TSSApep-II/V/VI ELISAs. The Chagas Sero K-Set detected TcII/V/VI infections in Leontopithecus spp. from the Atlantic forest (n = 46), in C. familiaris (n = 16) and Thrichomys laurentius (n = 2) from Caatinga biome and Chiroptera (n = 1) from Acre, Amazonia. The Chagas Sero K-SeT RDT is directly applicable to TcII/V/VI-specific serological surveillance of T. cruzi infection in several different mammalian Orders. It can replace ELISAs and provides efficient, point-of-sampling, low-cost detection of TcII/V/VI infections, with at least equivalent sensitivity, although some mammals may be difficult to trap, and, not unexpectedly, Chagas Sero K-SeT could not recognise feline IgG. Knowledge of sylvatic hosts of T. cruzi can be expanded, new reservoir species discovered, and the ecology of transmission cycles clarified, particularly with adaptation to further mammalian Orders

Lineage-specific rapid diagnostic tests can resolve Trypanosoma cruzi TcII/V/VI ecological and epidemiological associations in the Argentine Chaco.

BACKGROUND: Trypanosoma cruzi, the protozoan agent of Chagas disease, is comprised of at least 6 genetic lineages (TcI-TcVI). Their geographical distribution, clinical associations and reservoir hosts are not fully elucidated, as genotyping is hampered due to the difficulty in isolating representative populations of organisms. Lineage-specific serological techniques may address these issues. METHODS: Trypanosoma cruzi lineage-specific serological assays were performed on human, canine, feline and armadillo sera from the Gran Chaco in northern Argentina, a region of ongoing transmission. Synthetic peptides representing lineage-specific epitopes of the trypomastigote small surface antigen (TSSA) were used in ELISA, and the TcII/V/VI shared epitope peptide (TSSApep-II/V/VI) was used in the Chagas Sero K-SeT rapid diagnostic test (RDT). RESULTS: Chagas Sero K-SeT RDT, using Protein G to detect human and canine IgG, was at least as sensitive as TSSApep-II/V/VI ELISA using specific secondary antibodies. For sera from humans TSSApep-II/V/VI seroprevalence by Chagas Sero K-SeT was 273/393 (69.5%), for dogs 48/73 (65.8%) and for armadillos 1/7 (14.3%); by ELISA for cats 5/19 (26.3%). The seroprevalence for humans was similar to that for Bolivian patients, amongst whom we previously observed an association of TSSApep-II/V/VI seropositivity with severity of cardiomyopathy. In humans, prevalence of TSSApep-II/V/VI recognition was associated with locality, and with increasing and decreasing age within the Qom and Creole populations, respectively. For dogs TSSApep-II/V/VI recognition was associated with being born before community-wide insecticide spraying (P = 0.05) and with Qom household (P < 0.001). CONCLUSIONS: We show here that Chagas Sero K-SeT RDT can replace ELISA for TSSApep-II/V/VI serology of humans and dogs; for humans there were statistically significant associations between a positive Chagas Sero K-SeT RDT and being resident in Area IV, and for dogs association with Qom household or with being born before the mass spraying campaign; we also show that with cats the TcII/V/VI epitope can be detected by ELISA. We assessed the lineage distribution in an unprecedented 83% of the human T. cruzi-seropositive population. These results form the basis for more detailed studies, enabling rapid in-the-field surveillance of the distribution and clustering of these lineages among humans and mammalian reservoirs of T. cruzi infection