Étude de la plasticité du TA6V entre 25C et 800C

METZ-SCD (574632105) / SudocSudocFranceF

Release of immunoreactive oxytocin and neurophysin I by cultured luteinizing bovine granulosa cells

We investigated the production of oxytocin (OT) and oxytocin-neurophysin (bNpI) by bovine granulosa cells cultured in presence of 10% foetal calf serum, a condition known to induce spontaneous luteinization of these cells. The production of immunoreactive (ir) OT was significantly higher in the cultures harvested from large follicles than in those derived from small follicles. Chromatography on Sephadex G-25 showed similar elution sites of ovarian and synthetic OT, while HPLC revealed two peaks of irOT, one of which (±65%) coincided with synthetic OT. In another experiment, we could observe a gradual increase of OT, bNpI, and progesterone production by granulosa cells derived from large follicles, in relation with the incubation time. These data show that bovine granulosa cells are able to produce OT and bNpI, probably by an active biosynthesis as observed in the hypothalamo-neurohypophysial system and that the granulosa productions of OT, bNpI and progesterone are closely related

Long-term use of pitolisant to treat patients with narcolepsy: Harmony III Study

International audienceStudy objectives: To asses the long-term safety and efficacy of pitolisant, an histamine H3-receptor antagonist, on narcolepsy.Methods: This open-label, single-arm, pragmatic study, recruited adult patients with narcolepsy and Epworth Sleepiness Scale (ESS) score ≥12. After a titration period, patients were treated for up to 1 year with oral pitolisant once-a-day at up to 40 mg. Concomitant stimulants and anti-cataplectic agents were allowed. The primary endpoint was safety; secondary endpoints included ESS, cataplexy, and other diary parameters.Results: Patients (n = 102, 75 with cataplexy) received pitolisant, for the first time in 73 of them. Sixty-eight patients (51 with cataplexy) completed the 12-month treatment. Common treatment-emergent adverse events were headache (11.8% of patients), insomnia (8.8%), weight gain (7.8%), anxiety (6.9%), depressive symptoms (4.9%), and nausea (4.9%). Seven patients had a serious adverse effect, unrelated to pitolisant except for a possibly related miscarriage. One-third of patients stopped pitolisant, mostly (19.6%) for insufficient benefit. ESS score decreased by 4.6 ± 0.6. Two-thirds of patients completing the treatment were responders (ESS ≤ 10 or ESS decrease ≥ 3), and one third had normalized ESS (≤10). Complete and partial cataplexy, hallucinations, sleep paralysis, and sleep attacks were reduced by 76%, 65%, 54%, 63%, and 27%, respectively. Pitolisant as monotherapy (43% of patients) was better tolerated and more efficacious on ESS than on add-on, but efficacy was maintained in this last case

Diuretic and natriuretic responses in rats treated with enkephalinase inhibitors

International audienceRat atrial natriuretic factor (125I-rANF, 99-128) is hydrolysed by pure enkephalinase (EC 3.4.24.11) in vitro at a rate similar to that of 125I-hANF. Trichloroacetic precipitated radioactivity was significantly elevated in the kidneys of rats pretreated with acetorphan, an enkephalinase inhibitor, and receiving 125I-rANF, indicating that the exogenous hormone was protected against degradation. A single oral administration of acetorphan elicited diuretic and natriuretic effects in conscious normotensive rats and natriuretic effects in spontaneously hypertensive rats, effects which were not accompanied by significant changes in kaliuresis. The diuretic and natriuretic effects were still observed in conscious normotensive rats after three days of repeated administration of the drug. In conscious or anesthetized rats in which volume expansion was elicited by hydroelectrolytic loads, the initial rate of urinary elimination of water and sodium was nearly doubled by treatment with enkephalinase inhibitors. This effect was prevented by coadministration of an ANF antiserum, which suggests that the effect was mediated by endogenous ANF. These various observations suggest that enkephalinase inhibitors protect endogenous ANF from degradation and thereby enhance the typical renal effects of the hormone

Multiple twinning in pure hexagonal close-packed titanium

International audienceCommercial pure titanium (T40) was deformed in channel die compression by means of the split-sample technique in order to study multiple twinning. Particular attention was paid to the twin variant presentation and selection during multiple twinning. All possible misorientations, corresponding to the multiple twins arising from the combination of the \11 (2) over bar2\ compression (C) twin, the \10 (2) over bar2\ tension twin (T1) and the \11 (2) over bar1\ tension twin (T2), were calculated with respect to the crystal basis of the matrix grain. All the multiple twin variants are partitioned into ten classes with the same crystallographically equivalent misorientation angle and axis. However, when the influence of twinning order is taken into account, the multiple twin variants are partitioned into 15 classes. Experimental results prove that the selection of twin variants (primary and secondary) is mainly governed by their macroscopic Schmid factor (SF). The normalized SF is more efficient at predicting variant selection. A twin formed in one grain can activate another twin in a neighbouring grain, provided that the angle between the two twinning planes does not exceed 20 degrees

Modélisation de l'hétérogénéité de l'activité médicale pour améliorer la gestion hospitalière par groupes homogènes de malades

Since the early 1980s healthcare systems in the industrialized nations have been undergoing radical reform aimed at curbing overspending of hospital expenditure. After a discussion of the limits of a prospective payment due to heterogeneity of costs within DRGs, we demonstrate the ability of anovel statistical model to identify high cost patients. We derive from this statistical model an economic heuristic in order to account for high cost patients in budget allocation and a Structural and Contingent method is proposed as a budgeting tool. Economic analysis based on this modeling of DRG heterogeneity further reveals the potential for improving the equity and the efficiency of the prospective payment system by restricting its perverse effects. This model may also be used as a strategic management tool for hospitals or as a means for regulators to evaluate treatment andadmission practices so as to improve health care provision. This statistical analysis was designed on the basis of a mixture of Weibull distribution, inwhich proportion of high-cost patients was expressed according to the multinomial logistic regression, allowing the determination of high-cost factors. An application of the statistical model to 124 DRGs on a French reference database stresses the problem o f heterogeneity of costs and length ofstays within most of DRGs. An example of identification of explanatory variables of high costs is carried out on several DRGs. The economic application of the statistical model is discussed pointing out the implications, in terms of efficiency, of improving hospital management. The other advantageof this statistical model is to allow the assessment of a revision of the DRG classification from both statistical and economic point of views.Cette recherche a pour objectif de modéliser l'hétérogénéité de l'activité hospitalière afin d'améliorer la régulation hospitalière tant en externe qu'en interne dans une double perspective d'efficacité et d'équité. La première partie, rappelle les fondements théoriques d'une telle régulation et débouche sur l'élaboration d'un modèle pour l'analyse de l'hétérogénéité des coûts intra-GHM. Dans le chapitre 1, nous rappelons que la procédure du paiement à la pathologie s'appuie sur une contractualisation qui tend à contrecarrer les comportements opportunistes en repérant les établissements sur et sous dotés. Toutefois, la catégorisation des séjours en GHM engendre une nouvelle asymétrie d'information qui résulte de la diversité des pathologies et des prises en charge dans un GHM. Il s'ensuit un risque de sélection adverse des activités rentables et un risque moral de sous-consommation pour les patients coûteux. Pour assainir les coûts par GHM et obtenir une orientation plus incitative de la politique hospitalière, nous proposons au chapitre 2 une modélisation statistique par mélange de distributions qui repose sur l'hypothèse que l'hétérogénéité intra-GHM est le fait de la coexistence de souspopulations de patients qui diffèrent tant sur le plan clinique que sur le plan des coûts. La deuxième partie de cette recherche est consacrée à l'application de cette modélisation. Dans le chapitre 3, nous utilisons les sous-groupes de GHM pour modéliser la régulation hospitalière en interne comme en externe par la méthode dite de "Compensation Structurelle et Conjoncturelle". En ce qui concerne la gestion externe (chapitre 4), à partir de l'étude de 125 GHM extraits de la base nationale de l'étude de coûts, nous montrons que le problème de l'hétérogénéité des coûts concerne laplupart des GHM et nous estimons ses répercussions financières pour les établissements selon leur catégorie. Pour déterminer si ces surcoûts peuvent être expliqués par le recrutement de patients cliniquement plus coûteux et non pas par une inefficacité économique, une recherche de facteursexplicatifs des surcoûts est entreprise sur quelques GHM. Dans le chapitre 5 consacré à la gestion interne, nous discutons de l'intérêt de la modélisation par sous-groupes pour l'analyse des écarts entre les dépenses réelles et théoriques d'un service, à partir de l'exemple du service d'hématologie du CHU de Dijon

Study of twinning/detwinning behaviors of Ti by interrupted in situ tensile tests

International audienceIn this paper Ti (T40) is deformed by interrupted in situ tensile tests. Twinning activation and evolution are evidenced by scanning electron microscopy/electron backscatter diffraction and analyzed by examining their strain accommodation in the frame of all the potential accommodative systems in their neighborhoods. It is revealed that the formation of twins results from the local incompatible strains produced by dislocation slips in grain boundary areas. Either high positive Schmid factor and low positive Schmid factor twins or even negative Schmid factor twins could be activated. Twins are always accompanied by certain accommodative deformation (twinning and slip) in their immediate neighborhoods. Accommodative slips and twins have different impacts on the further development of the initiating twins. Twins accommodated by twins and possessing high Schmid factors have a higher capacity to propagate and repeatedly nucleate; whereas twins accommodated by slips and possessing low Schmid factors have less power and are static. Twins can be permanent or transient depending on their Schmid factors. For those with positive Schmid factors, their strain contributions are consistent with the macroscopic strains, thus they are stable, whereas those with negative Schmid factors are unstable. The formation of such twins is due to the unbalanced local constraints induced by high Schmid factor deformation that generate the so-called back-stress. These twins make opposite contributions to the macroscopic strains. With deformation, the back-stress could be accommodated by local high Schmid factor compatible deformation. The crystal of the twinned part has to make a positive contribution in accordance with the macroscopic strains to be compatible with its surroundings, which may give rise to the activation of detwinning