MADS: un modèle conceptuel pour des applicationsspatio-temporelles

Malgré les bienfaits reconnus de l'approche conceptuelle pour la modélisation d'applications, les modèles conceptuels spatio-temporels existants ne satisfont pas les besoins des concepteurs. Dans cet article nous identifions d'abord les objectifs d'un modèle conceptuel spatio-temporel et ensuite nous présentons le modèle MADS selon trois axes: concepts structu-rels, concepts spatiaux, concepts temporels. L'orthogonalité des concepts permet d'obtenir un modèle à la fois simple (puisque ces concepts sont indépendants) et puissant (puisque les con-cepts peuvent être combinés librement). Le modèle a été implanté et des traductions existent vers d'autres modèles opérationnels. L'article décrit brièvement les réalisations en cours ou prévues pour offrir aux utilisateurs une interface conceptuelle de définition et d'accès aux bases de données spatio-temporelles. Nous donnons également les résultats d'une expérience de mo-délisation qui a permis de vérifier les qualités du modèle

Characterization of the innate immune response to chronic aspiration in a novel rodent model

<p>Abstract</p> <p>Background</p> <p>Although chronic aspiration has been associated with several pulmonary diseases, the inflammatory response has not been characterized. A novel rodent model of chronic aspiration was therefore developed in order to investigate the resulting innate immune response in the lung.</p> <p>Methods</p> <p>Gastric fluid or normal saline was instilled into the left lung of rats (n = 48) weekly for 4, 8, 12, or 16 weeks (n = 6 each group). Thereafter, bronchoalveolar lavage specimens were collected and cellular phenotypes and cytokine concentrations of IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-gamma, TNF-alpha, and TGF-beta were determined.</p> <p>Results</p> <p>Following the administration of gastric fluid but not normal saline, histologic specimens exhibited prominent evidence of giant cells, fibrosis, lymphocytic bronchiolitis, and obliterative bronchiolitis. Bronchoalveolar lavage specimens from the left (treated) lungs exhibited consistently higher macrophages and T cells with an increased CD4:CD8 T cell ratio after treatment with gastric fluid compared to normal saline. The concentrations of IL-1alpha, IL-1beta, IL-2, TNF-alpha and TGF-beta were increased in bronchoalveolar lavage specimens following gastric fluid aspiration compared to normal saline.</p> <p>Conclusion</p> <p>This represents the first description of the pulmonary inflammatory response that results from chronic aspiration. Repetitive aspiration events can initiate an inflammatory response consisting of macrophages and T cells that is associated with increased TGF-beta, TNF-alpha, IL-1alpha, IL-1beta, IL-2 and fibrosis in the lung. Combined with the observation of gastric fluid-induced lymphocyitic bronchiolitis and obliterative bronchiolitis, these findings further support an association between chronic aspiration and pulmonary diseases, such as obliterative bronchiolitis, pulmonary fibrosis, and asthma.</p

Testis size, sperm characteristics and testosterone concentrations in four species of shrews (Mammalia, Soricidae).

The aim of this study was to establish and compare the sperm characteristics in four shrew species in the context of the sperm competition hypothesis. As expected, the large relative testis size in promiscuous species was associated with a high number of cauda epididymal spermatozoa and a high concentration of circulating testosterone. In addition, in Sorex and Neomys, species with high intensity of sperm competition, the spermatozoa stored in cauda epididymis were characterized by high percentage of progressive motility whereas in Crocidura and Suncus, the cauda epididymal spermatozoa were motile but with very low percentage of progressive motility. This capability is achieved only following the passage through the vas gland, a specialized region for sperm storage located along the vas deferens in these shrew species. The hypothesis that sperm competition is positively correlated with spermatozoa length could not be confirmed. In Crocidura and Suncus, the total sperm length is increased by the large sperm head due to a big acrosome. This trait, specific to the subfamily Crocidurinae, may results from a selective pressure independent of the context of sperm competition, related to a specific, but as yet unclear role, for the acrosome during the fertilization

Release patterns of astrocytic and neuronal biochemical markers in serum during and after experimental settings of cardiac surgery

OBJECTIVE: Brain injury and altered psychomotor development in infants, children and adults after cardiac surgery using cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) is still a matter of concern. Early diagnosis and identification of brain injury that has occurred or is ongoing by measurement of biochemical markers in serum may have diagnostic and prognostic value. The aim of the experimental studies in an animal model was therefore to investigate the release patterns of astroglial and neuronal markers in serum and to determine the morphological and immunohistochemical changes in the brain of animals undergoing similar perfusion conditions of CPB and a period of DHCA. METHODS: Fourteen New Zealand rabbits, (weight, 3.1 +/- 0.25 kg) were anesthetized, intubated and mechanically ventilated. Four animals were sham operated and served as controls. After median sternotomy the animals were connected to CPB by cannulation of the aorta and right atrium. Full flow CPB (200-250 ml/kg/min) was initiated to achieve homogeneous systemic cooling. Circulatory arrest of 60 minutes was induced when rectal and nasopharyngeal temperature of 14 degrees C was achieved. After rewarmed reperfusion and establishment of stable cardiac ejection the animals were weaned from CPB and monitored for 6 hours. Then the animals were killed, the brain was immediately removed and cut in standardized sections. These were fixated, embedded in paraffin and stained for further quantitative histological studies. In the brain astrocyte reactivity for S-100B was assessed immunocytochemically (DPC Immustain Los Angeles, USA). Monoclonal mouse anti-human neurospecific enolase (NSE) antibody was used for the localization of NSE in the fixed and paraffin embedded brain (NSE-DAKO, H14). The concentrations of S-100B protein and neurospecific enolase (NSE) in the serum were analyzed using a commercially available immunoluminometric assay (LIA-mat, Sangtec 100, Byk-Sangtec). Immunospecific monoclonal anti-parvalbumin antibody was used for the detection of parvalbumin in the brain. Serum concentrations of parvalbumin were analyzed using a newly developed ELISA method. RESULTS: In all experimental animals a significant increase of the serum concentration of the astroglial protein S-100B was found immediately after reperfusion and the termination of CPB. In contrast the serum levels of the neuronal proteins parvalbumin and NSE were not increased, but rather decreased. Light microscopy and electron microscopy revealed perivascular astrocytic swelling and minor neuronal cell injury. In comparison to the sham operated animals, increased immunohistochemical staining of S-100B was found. This increased reactivity of S100B antibody was found in the astrocytic processes with immediate connection to the perivascular space and around the perivascular oedema. The immunocytochemical stainings for NSE and parvalbumin in the neuronal cells was not different from that of sham-operated animals and indicated well preserved neurons

Elongation factor 1a mediates the specificity of mitochondrial tRNA import in T. brucei

Mitochondrial tRNA import is widespread in eukaryotes. Yet, the mechanism that determines its specificity is unknown. Previous in vivo experiments using the tRNAsMet, tRNAIle and tRNALys have suggested that the T-stem nucleotide pair 51:63 is the main localization determinant of tRNAs in Trypanosoma brucei. In the cytosol-specific initiator tRNAMet, this nucleotide pair is identical to the main antideterminant that prevents interaction with cytosolic elongation factor (eEF1a). Here we show that ablation of cytosolic eEF1a, but not of initiation factor 2, inhibits mitochondrial import of newly synthesized tRNAs well before translation or growth is affected. tRNASec is the only other cytosol-specific tRNA in T. brucei. It has its own elongation factor and does not bind eEF1a. However, a mutant of the tRNASec expected to bind to eEF1a is imported into mitochondria. This import requires eEF1a and aminoacylation of the tRNA. Thus, for a tRNA to be imported into the mitochondrion of T. brucei, it needs to bind eEF1a, and it is this interaction that mediates the import specificity