148 resultados para Collaborative processes
Resumo:
Forensic scientists working in 12 state or private laboratories participated in collaborative tests to improve the reliability of the presentation of DNA data at trial. These tests were motivated in response to the growing criticism of the power of DNA evidence. The experts' conclusions in the tests are presented and discussed in the context of the Bayesian approach to interpretation. The use of a Bayesian approach and subjective probabilities in trace evaluation permits, in an easy and intuitive manner, the integration into the decision procedure of any revision of the measure of uncertainty in the light of new information. Such an integration is especially useful with forensic evidence. Furthermore, we believe that this probabilistic model is a useful tool (a) to assist scientists in the assessment of the value of scientific evidence, (b) to help jurists in the interpretation of judicial facts and (c) to clarify the respective roles of scientists and of members of the court. Respondents to the survey were reluctant to apply this methodology in the assessment of DNA evidence.
Resumo:
The significance of the Brianconnais domain in the Alpine orogen is reviewed in the light of data concerning its collision with the active Adriatic margin and the passive Helvetic margin. The Brianconnais which formerly belonged to the Iberian plate, was located on the northern margin of the Alpine Tethys (Liguro-Piemont ocean) since its opening in the early-Middle Jurassic. Together with the Iberian plate the Brianconnais terrane was separated from the European plate in the Late Jurassic-Early Cretaceous, following the northern Atlantic, Bay of Biscay, Valais ocean opening. This was accompanied by the onset of subduction along the northern margin of Adria and the closure of the Alpine Tethys. Stratigraphic and metamorphic data regarding this subduction and the geohistory of the Brianconnais allows the scenario of subduction-obduction processes during the Late Cretaceous-early Tertiary in the eastern and western Alps to be specified. HP-LT metamorphism record a long-lasting history of oceanic subduction-accretion, followed in the Middle Eocene by the incorporation of the Brianconnais as an exotic terrane into the accretionary prism. Middle to Late Eocene cooling ages of the Brianconnais basement and the presence of pelagic, anorogenic sedimentation lasting until the Middle Eocene on the Brianconnais preclude any sort of collision before that time between this domain and the active Adria margin or the Helvetic margin. This is confirmed by plate reconstructions constrained by magnetic anomalies in the Atlantic domain. Only a small percentage of the former Brianconnais domain was obducted, most of the crust and lithospheric roots were subducted. This applies also to domains formerly belonging to the southern Alpine Tethys margin (Austroalpine-inner Carpathian domain). It is proposed that there was a single Palaeogene subduction zone responsible for the Alpine orogen formation (from northern Spain to the East Carpathians), with the exception of a short-lived Late Cretaceous partial closure of the Valais ocean. Subduction in the western Tethyan domain originated during the closure of the Meliata ocean during the Jurassic incorporating the Austroalpine-Carpathian domain as terranes during the Cretaceous. The subduction zone propagated into the northern margin of Adria and then to the northern margin of the Iberian plate, where it gave birth to the Pyrenean-Provencal orogenic belt. This implies the absence of a separated Cretaceous subduction zone within the Austro-Carpathian Penninic ocean. Collision of Iberia with Europe forced the subduction to jump to the SE margin of Iberia in the Eocene, creating the Apenninic orogenic wedge and inverting the vergence of subduction from south- to north-directed. (C) 1998 Elsevier Science B.V. All rights reserved.
Resumo:
During the last decade, evidence that release of chemical transmitters from astrocytes might modulate neuronal activity (the so-called "gliotransmission") occurs in situ has been extensively provided. Nevertheless, gliotransmission remains a highly debated topic because of the lack of direct morphological and functional evidence. Here we provided new information supporting gliotransmission, by i) deepen knowledge about specific properties of regulated secretion of glutamatergic SLMVs, and ii) investigating the involvement of astrocytes in the transmission of dopamine, a molecule whose interaction with astrocytes is likely to occur, but it's still not proven.¦VGLUT-expressing glutamatergic SLMVs have been previously identified both in situ and in vitro, but description of kinetics of release were still lacking. To elucidate this issue, we took advantage of fluorescent tools (styryl dyes and pHluorin) and adapted experimental paradigms and analysis methods previously developed to study exo-endocytosis and recycling of glutamatergic vesicles at synapses. Parallel use of EPIfluorescence and total internal reflection (TIRF) imaging allowed us to find that exo-endocytosis processes in astrocytes are extremely fast, with kinetics in the order of milliseconds, able to sustain and follow neuronal signalling at synapses. Also, exocytosis of SLMVs is under the control of fast, localized Ca2+ elevations in close proximity of SLMVs and endoplasmatic reticulum (ER) tubules, the intracellular calcium stores. Such complex organization supports the fast stimulus-secretion coupling we described; localized calcium elevations have been recently observed in astrocytes in situ, suggesting that these functional microdomains might be present in the intact tissue. In the second part of the work, we investigated whether astrocytes possess some of the benchmarks of brain dopaminergic cells. It's been known for years that astrocytes are able to metabolize monoamines by the enzymes MAO and COMT, but to date no clear information that glial cells are able to uptake and store monoamines have been provided. Here, we identified a whole apparatus for the storage, degradation and release of monoamines, at the ultrastructural level. Electron microscopy immunohistochemistry allowed us to visualize VMAT2- and dopamine-positive intracellular compartments within astrocytic processes, i.e. dense -core granules and cisterns. These organelles might be responsible for dopamine release and storage, respectively; interestingly, this intracellular distribution is reminiscent of VMAT2 expression in dendrites if neurons, where dopamine release is tonic and plays a role in the regulation of its a basal levels, suggesting that astrocytic VMAT2 is involved in the homeostasis of dopamine in healthy brains of adult mammals.¦Durant cette dernière décennie, de nombreux résultats sur le relâchement des transmetteurs par les astrocytes pouvant modulé l'activité synaptique (gliotransmission) ont été fournis. Néanmoins, la gliotransmission reste un processus encore très débattu, notamment à cause de l'absence de preuves directes, morphologique et fonctionnelle démontrant ce phénomène. Nous présentons dans nos travaux de nombreux résultats confortant l'hypothèse de la gliotransmission, dont i) une étude approfondie sur les propriétés spatiales et temporelles de la sécrétion régulée du glutamate dans les astrocytes, et ii) une étude sur la participation des astrocytes dans la transmission de la dopamine, une neuromodulateur dont l'interaction avec les astrocytes est fortement probable, mais qui n'a encore jamais été prouvée. L'expression des petites vésicules (SLMVs - Synaptic Like Micro Vesicles) glutamatergiques exprimant les transporteurs vésiculaires du glutamate (VGLUTs) dans les astrocytes a déjà été prouvé tant in situ qu'in vitro. Afin de mettre en évidence les propriétés précises de la sécrétion de ces organelles, nous avons adapté à nos études des méthodes expérimentales conçues pour observer les processus de exocytose et endocytose dans les neurones. Les résolutions spatiale et temporelle obtenues, grâce a l'utilisation en parallèle de l'épi fluorescence et de la fluorescence a onde évanescente (TIRF), nous ont permis de montrer que la sécrétion régulée dans les astrocytes est un processus extrêmement rapide (de l'ordre de la milliseconde) et qu'elle est capable de soutenir et de suivre la transmission de signaux entre neurones. Nous avons également découvert que cette sécrétion a lieu dans des compartiments subcellulaires particuliers où nous observons la présence du reticulum endoplasmique (ER) ainsi que des augmentations rapides de calcium. Cette organisation spatiale complexe pourrait être la base morphologique du couplage rapide entre le stimulus et la sécrétion. Par ailleurs, plusieurs études récentes in vivo semblent confirmer l'existence de ces compartiments. Depuis des années nous savons que les astrocytes sont capables de métaboliser les monoamines par les enzymes MAO et COMT. Nous avons donc fourni de nouvelles preuves concernant la présence d'un appareil de stockage dans les astrocytes participant à la dégradation et la libération de monoamines au niveau ultrastructurelle. Grâce à la microscopie électronique, nous avons découvert la présence de compartiments intracellulaires exprimant VMAT2 dans les processus astrocytaires, sous forme de granules et des citernes. Ces organelles pourraient donc être responsables à la fois du relâchement et du stockage de la dopamine. De manière surprenante, cette distribution intracellulaire est similaire aux dendrites des neurones exprimant VMAT2, où la dopamine est libérée de façon tonique permettant d'agir sur la régulation de ses niveaux de base. Ces résultats, suggèrent une certaine participation des VMAT2 présents dans les astrocytes dans le processus d'homéostase de la dopamine dans le cerveau.¦A de nombreuses reprises, dans des émissions scientifiques ou dans des films, il est avancé que les hommes n'utilisent que 10% du potentiel de leur cerveau. Cette légende provient probablement du fait que les premiers chercheurs ayant décrit les cellules du cerveau entre le XIXème et le XXeme siècle, ont montré que les neurones, les cellules les plus connues et étudiées de cet organe, ne représentent seulement que 10% de la totalité des cellules composant du cerveau. Parmi les 90% restantes, les astrocytes sont sans doute les plus nombreuses. Jusqu'au début des années 90, les astrocytes ont été plutôt considérés peu plus que du tissu conjonctif, ayant comme rôles principaux de maintenir certaines propriétés physiques du cerveau et de fournir un support métabolique (énergie, environnement propre) aux neurones. Grace à la découverte que les astrocytes ont la capacité de relâcher des substances neuro-actives, notamment le glutamate, le rôle des astrocytes dans le fonctionnement cérébral a été récemment reconsidérée.¦Le rôle du glutamate provenant des astrocytes et son impact sur la fonctionnalité des neurones n'a pas encore été totalement élucidé, malgré les nombreuses publications démontrant l'importance de ce phénomène en relation avec différentes fonctions cérébrales. Afin de mieux comprendre comment les astrocytes sont impliqués dans la transmission cérébrale, nous avons étudié les propriétés spatio-temporelles de cette libération grâce à l'utilisation des plusieurs marqueurs fluorescents combinée avec différentes techniques d'imagerie cellulaires. Nous avons découvert que la libération du glutamate par les astrocytes (un processus maintenant appelé "gliotransmission") était très rapide et contrôlée par des augmentations locales de calcium. Nous avons relié ces phénomènes à des domaines fonctionnels subcellulaires morphologiquement adaptés pour ce type de transmission. Plus récemment, nous avons concentré nos études sur un autre transmetteur très important dans le fonctionnement du cerveau : la dopamine. Nos résultats morphologiques semblent indiquer que les astrocytes ont la capacité d'interagir avec ce transmetteur, mais d'une manière différente comparée au glutamate, notamment en terme de rapidité de transmission. Ces résultats suggèrent que le astrocytes ont la capacité de modifier leurs caractéristiques et de s'adapter à leur environnement par rapport aux types de transmetteur avec lequel ils doivent interagir.
Resumo:
Introduction: Mirtazapine is a noradrenergic and serotonergic antidepressant mainly acting through blockade of presynaptic alpha-2 receptors. Published data on pregnancy outcome after exposure to mirtazapine are scarce. This study addresses the risk associated with exposure to mirtazapine during pregnancy. Patients (or Materials) and Methods: Multicenter (n = 11), observational prospective cohort study comparing pregnancy outcomes after exposure to mirtazapine with 2 matched control groups: exposure to any selective serotonin reuptake inhibitor (SSRI) as a diseasematched control group, and general controls with no exposure to medication known to be teratogenic or to any antidepressant. Data were collected by members of the European Network of Teratology Information Services (ENTIS) during individual risk counseling between 1995 and 2011. Standardized procedures for data collection were used in each center. Results: A total of 357 pregnant women exposed to mirtazapine at any time during pregnancy were included in the study and compared with 357 pregnancies from each control group. The rate of major birth defects between the mirtazapine and the SSRI group did not differ significantly (4.5% vs 4.2%; unadjusted odds ratio, 1.1; 95% confidence interval, 0.5-2.3, P = 0.9). A trend toward a higher rate of birth defects in the mirtazapine group compared with general controls did not reach statistical significance (4.2% vs 1.9%; OR, 2.4; 95% CI, 0.9-6.3; P = 0.08). The crude rate of spontaneous abortions did not differ significantly between the mirtazapine, the SSRI, and the general control groups (9.5% vs 10.4% vs 8.4%; P = 0.67), neither did the rate of deliveries resulting in live births (79.6% vs 84.3% in both control groups; P = 0.15). However, a higher rate of elective pregnancy-termination was observed in the mirtazapine group compared with SSRI and general controls (7.8% vs 3.4% vs 5.6%; P = 0.03). Premature birth (< 37 weeks) (10.6% vs 10.1% vs 7.5%; P = 0.38), gestational age at birth (median, 39 weeks; interquartile range (IQR), 38-40 in all groups; P = 0.29), and birth weight (median, 3320 g; IQR, 2979-3636 vs 3230 g; IQR, 2910-3629 vs 3338 g; IQR, 2967-3650; P = 0.34) did not differ significantly between the groups. Conclusion: This study did not observe a statistically significant difference in the rate of major birth defects between mirtazapine, SSRI-exposed, and nonexposed pregnancies. A slightly higher rate of birth defects was, however, observed in the mirtazapine and SSRI groups compared with the low rate of birth defects in our general controls. Overall, the pregnancy outcome after mirtazapine exposure in this study is very similar to that of the SSRI-exposed control group.
Resumo:
Venous thromboembolism (VTE) is common and has a high impact on morbidity, mortality, and costs of care. Although most of the patients with VTE are aged ≥65 years, there is little data about the medical outcomes in the elderly with VTE. The Swiss Cohort of Elderly Patients with VTE (SWITCO65+) is a prospective multicenter cohort study of in- and outpatients aged ≥65 years with acute VTE from all five Swiss university and four high-volume non-university hospitals. The goal is to examine which clinical and biological factors and processes of care drive short- and long-term medical outcomes, health-related quality of life, and medical resource utilization in elderly patients with acute VTE. The cohort also includes a large biobank with biological material from each participant. From September 2009 to March 2012, 1,863 elderly patients with VTE were screened and 1003 (53.8 %) were enrolled in the cohort. Overall, 51.7 % of patients were aged ≥75 years and 52.7 % were men. By October 16, 2012, after an average follow-up time of 512 days, 799 (79.7 %) patients were still actively participating. SWITCO65+ is a unique opportunity to study short- and long-term outcomes in elderly patients with VTE. The Steering Committee encourages national and international collaborative research projects related to SWITCO65+, including sharing anonymized data and biological samples.
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Bipolar disorder has a genetic component, but the mode of inheritance remains unclear. A previous genome scan conducted in 70 European families led to detect eight regions linked to bipolar disease. Here, we present an investigation of whether the phenotypic heterogeneity of the disorder corresponds to genetic heterogeneity in these regions using additional markers and an extended sample of families. The MLS statistic was used for linkage analyses. The predivided sample test and the maximum likelihood binomial methods were used to test genetic homogeneity between early-onset bipolar type I (cut-off of 22 years) and other types of the disorder (later onset of bipolar type I and early-onset bipolar type II), using a total of 138 independent bipolar-affected sib-pairs. Analysis of the extended sample of families supports linkage in four regions (2q14, 3p14, 16p23, and 20p12) of the eight regions of linkage suggested by our previous genome scan. Heterogeneity testing revealed genetic heterogeneity between early and late-onset bipolar type I in the 2q14 region (P = 0.0001). Only the early form of the bipolar disorder but not the late form appeared to be linked to this region. This region may therefore include a genetic factor either specifically involved in the early-onset bipolar type I or only influencing the age at onset (AAO). Our findings illustrate that stratification according to AAO may be valuable for the identification of genetic vulnerability polymorphisms.
Resumo:
Li contents [Li] and isotopic composition (delta Li-7) of mafic minerals (mainly amphibole and clinopyroxene) from the alkaline to peralkaline Ilimaussaq plutonic complex, South Greenland, track the behavior of Li and its isotopes during magmatic differentiation and final cooling of an alkaline igneous system. [Li] in amphibole increase from < 10 ppm in Caamphiboles of the least differentiated unit to >3000 ppm in Na-amphiboles of the highly evolved units. In contrast, [Li] in clinopyroxene are comparatively low (<85 ppm) and do not vary systematically with differentiation. The distribution of Li between amphibole and pyroxene is controlled by the major element composition of the minerals (Ca-rich and Na-rich, respectively) and changes in oxygen fugacity (due to Li incorporation via coupled substitution with ferric iron) during magmatic differentiation. delta(7) Li values of all minerals span a wide range from + 17 to - 8 parts per thousand, with the different intrusive units of the complex having distinct Li isotopic systematics. Amphiboles, which dominate the Li budget of whole-rocks from the inner part of the complex, have constant delta Li-7 of + 1.8 +/- 2.2 parts per thousand (2 sigma, n = 15). This value reflects a homogeneous melt reservoir and is consistent with their mantle derivation, in agreement with published O and Nd isotopic data. Clinopyroxenes of these samples are consistently lighter, with Delta Li-7(amph-cpx). as large as 8 parts per thousand and are thus not in Li isotope equilibrium. These low values probably reflect late-stage diffusion of Li into clinopyroxene during final cooling of the rocks, thus enriching the clinopyroxene in 6 Li. At the margin of the complex delta(7) Li in the syenites increases systematically, from +2 to high values of + 14 parts per thousand. This, coupled with the observed Li isotope systematics of the granitic country rocks, reflects post-magmatic open-system processes occurring during final cooling of the intrusion. Although the shape and magnitude of the Li isotope and elemental profiles through syenite and country rock are suggestive of diffusion-driven isotope fractionation, they cannot be modeled by one-dimensional diffusive transport and point to circulation of a fluid having a high 67 Li value (possibly seawater) along the chilled contact. In all, this study demonstrates that Li isotopes can be used to identify complex fluid- and diffusion-governed processes taking place during the final cooling of such rocks. (c) 2007 Elsevier B.V All rights reserved.