61 resultados para Tri-Iodotironina
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Résumé Objectif: l'observation des variations de volume de la matière grise (MG), de la matière blanche (MB), et du liquide céphalo-rachidien (LCR) est particulièrement utile dans l'étude de nombreux processus physiopathologiques, la mesure quantitative 'in vivo' de ces volumes présente un intérêt considérable tant en recherche qu'en pratique clinique. Cette étude présente et valide une méthode de segmentation automatique du cerveau avec mesure des volumes de MG et MB sur des images de résonance magnétique. Matériel et Méthode: nous utilisons un algorithme génétique automatique pour segmenter le cerveau en MG, MB et LCR à partir d'images tri-dimensionnelles de résonance magnétique en pondération Ti. Une étude morphométrique a été conduite sur 136 sujets hommes et femmes de 15 à 74 ans. L'algorithme a ensuite été validé par 5 approches différentes: I. Comparaison de mesures de volume sur un cerveau de cadavre par méthode automatique et par mesure de déplacement d'eau selon la méthode d'Archimède. 2. Comparaison de mesures surfaces sur des images bidimensionnelles segmentées soit par un traçage manuel soit par la méthode automatique. 3. Evaluation de la fiabilité de la segmentation par acquisitions et segmentations itératives du même cerveau. 4. Les volumes de MG, MB et LCR ont été utilisés pour une étude du vieillissement normal de la population. 5. Comparaison avec les données existantes de la littérature. Résultats: nous avons pu observer une variation de la mesure de 4.17% supplémentaire entre le volume d'un cerveau de cadavre mesuré par la méthode d'Archimède, en majeure partie due à la persistance de tissus après dissection_ La comparaison des méthodes de comptage manuel de surface avec la méthode automatique n'a pas montré de variation significative. L'épreuve du repositionnement du même sujet à diverses reprises montre une très bonne fiabilité avec une déviation standard de 0.46% pour la MG, 1.02% pour la MB et 3.59% pour le LCR, soit 0.19% pour le volume intracrânien total (VICT). L'étude morphométrique corrobore les résultats des études anatomiques et radiologiques existantes. Conclusion: la segmentation du cerveau par un algorithme génétique permet une mesure 100% automatique, fiable et rapide des volumes cérébraux in vivo chez l'individu normal.
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BACKGROUND: Cardiopulmonary bypass (CPB) with aortic cross-clamping and cardioplegic arrest remains the method of choice for patients requiring standard myocardial revascularization. Therefore, very high-risk patients presenting with acute coronary syndrome, unstable angina, onset of cardiac decompensation and requiring emergency multiple myocardial revascularization, can have a poor outcome. The on-pump beating heart technique can reduce the mortality and the morbidity in such a selected group of patients and this report describes our clinical experience. METHODS: Out of 290 patients operated for CABG from January 2005 to January 2006, 25 (8.6%) selected high-risk patients suffering from life threatening coronary syndrome (mean age 69 +/- 7 years) and requiring emergency multiple myocardial revascularization, underwent on-pump beating heart surgery. The mean pre-operative left ventricle ejection fraction (LVEF) was 27 +/- 8%. The majority of them (88%) suffered of tri-vessel coronary disease and 6 (24%) had a left main stump disease. Nine patients (35%) were on severe cardiac failure and seven among them (28%) received a pre-operative intra-aortic balloon pump. The pre-operative EuroScore rate was equal or above 8 in 18 patients (73%). RESULTS: All patients underwent on-pump-beating heart coronary revascularization. The mean number of graft/patient was 2.9 +/- 0.6 and the internal mammary artery was used in 23 patients (92%). The mean CPB time was 84 +/- 19 minutes. Two patients died during the recovery stay in the intensive care unit, and there were no postoperative myocardial infarctions between the survivors. Eight patients suffered of transitorily renal failure and 1 patient developed a sternal wound infection. The mean hospital stay was 12 +/- 7 days. The follow-up was complete for all 23 patients survived at surgery and the mean follow-up time was 14 +/- 5 months. One patient died during the follow-up for cardiac arrest and 2 patients required an implantable cardiac defibrillator. One year after surgery they all had a standard trans-thoracic echocardiogram showing a mean LVEF rate of 36 +/- 11.8%. CONCLUSION: Standard on-pump arrested heart coronary surgery has higher mortality and morbidity in emergencies. The on-pump beating heart myocardial revascularization seems to be a valid alternative for the restricted and selected cohort of patients suffering from life threatening coronary syndrome and requiring multiple emergency CABG.
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Objectives: Our aim was to study the brain regions involved in a divided attention tracking task related to driving in occasional cannabis smokers. In addition we assessed the relationship between THC levels in whole blood and changes in brain activity, behavioural and psychomotor performances. Methods: Twenty-one smokers participated to two independent cross-over fMRI experiments before and after smoking cannabis and a placebo. The paradigm was based on a visuo-motor tracking task, alternating active tracking blocks with passive tracking viewing and rest condition. Half of the active tracking conditions included randomly presented traffic lights as distractors. Blood samples were taken at regular intervals to determine the time-profiles of the major cannabinoids. Their levels during the fMRI experiments were interpolated from concentrations measured by GCMS/ MS just before and after brain imaging. Results: Behavioural data, such as the discard between target and cursor, the time of correct tracking and the reaction time during traffic lights appearance showed a statistical significant impairment of subject s skills due to THC intoxication. Highest THC blood concentrations were measured soon after smoking and ranged between 28.8 and 167.9 ng/ml. These concentrations reached values of a few ng/ml during the fMRI. fMRI results pointed out that under the effect of THC, high order visual areas (V3d) and Intraparietal sulcus (IPS) showed an higher activation compared to the control condition. The opposite comparison showed a decrease of activation during the THC condition in the anterior cingulate gyrus and orbitofrontal areas. In these locations, the BOLD showed a negative correlation with the THC level. Conclusion: Acute cannabis smoking significantly impairs performances and brain activity during active tracking tasks, partly reorganizing the recruitment of brain areas of the attention network. Neural activity in the anterior cingulate might be responsible of the changes in the cognitive controls required in our divided attention task.
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Résumé Introduction : Plusieurs études américaines et australiennes ont décrit des systèmes de tri téléphonique des urgences pédiatriques. En Europe, les services publics d'urgences pédiatriques ont peu de données épidémiologiques sur lesquelles s'appuyer pour répondre à la demande de soins. Depuis 1996, le département de pédiatrie de l'hôpital Pourtalès, Neuchâtel, offre, en dehors des heures ouvrables, mi tri téléphonique infirmier gratuit. Le présent travail analyse : 1) la situation suisse de l'offre en tri téléphonique infirmier pour les urgences pédiatriques ; 2) une partie des données épidémiologiques de l'expérience neuchâteloise. Méthode : 1) Un questionnaire a été envoyé aux 35 services d'urgences pédiatriques publics de Suisse pour Savoir si un tel tri était utilisé ; 2) une analyse rétrospective de tous les appels reçus, consignés sur fiches standardisées, en 1997 et 2000 a été menée. Résultats : 1) La majorité des services (27/35) ont effectivement un système de tri infirmier. Peu offrent une formation spécifique pour ce travail (14/27) ; 2) Au total, 7870 appels ont été analysés (3242 en 1997; 4628 en 2000, ± 43%). En semaine, la majorité ont été reçus entre 18h et 23h et le week-end en milieu de matinée. Septante-cinq % des appels ont concerné des enfants de 5 ans ou moins. La fièvre, les otalgies et la toux ont représenté 42% des plaintes. Vingt-sept % des appels ont été pris en charge uniquement par les conseils infirmiers, 15 % ont été transmis à l'interne de garde et 50% ont conduit à un rendez-vous dans le service le jour même. Conclusion : Nos données peuvent aider d'autres services d'urgences pédiatriques à planifier au mieux la mise en place d'un tel système de tri téléphonique. Abstract Delivery of paediatric primary care by call centres has emerged as a satisfactory system. It been reported in the literature in the United States and Australia. European public-funded paediatric emergency departments (ED) have little epidemiological data to rely on to match the demand in care. Since 1996, we have run a free nurse-led after-hours paediatric telephone triage and advice (TTA) system, To determine wether other Swiss public paediatric departments practiced formal TTA, we conducted a nation-wide postal survey. To delineate who used our call centre and for what reasons, we embarked on a retrospective study of ail the 1997/2000 calls. Most of the units run a TTA (27/35) but few specifically train their staff (14/27). A 43% increase in call numbers was seen between 1997 (3242) and 2000 (4628). During week-days, most of the calls were between 6 and 11 pm and at weekends, a mid morning activity peak was seen. Some 75% of calls were for children aged 5 years or less. Fever, earache and cough accounted for 42% of the main complaints. Of all calls, 27% were dealt by nurses' advice only. About 15% of the calls were transferred to the on-call resident. About 50% led to a same day ED appointment. Conclusion: Nurse-led paediatric telephone triage and advice is common in Switzerland where training seems to be irregular. Our data can help units to better plan an eventual paediatric telephone triage and advice service. After-hours; Paediatric; Telephone advice; Telephone triage
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Résumé : Les jasmonates (JA), une famille d'hor1none végétale, jouent un rôle central dans la réponse à la blessure, et aux attaques d'insectes et de pathogènes. Les JA sont principalement dérivés d'un acide gras, l'acide linolénique. L'addition par une lipoxygénase d'une molécule d'oxygène à l'acide linolénique initie la synthèse de JA. Cependant les mécanismes régulant l'activation de la biosynthèse de JA ne sont pas encore connus. C'est pour cette raison que dans ce travail, nous avons caractérisé chez Arabidopsis thaliana (l'Arabette des Dames) un mutant fou2 dont l'activité lipoxygénase est plus élevée que celle d'une plante sauvage. Les niveaux de JA sont constitutivement plus élevés et l'activation de la synthèse de JA après blessure est fortement plus induite chez fou2 que chez le type sauvage. En outre, fou2 est plus résistant au pathogène Botrytis cinerea et à la chenille Spodoptera littoralis. Afin de comprendre quel mécanisme chez fou2 génére ce phénotype, nous avons cloné le gène responsable du phénotype de fou2. Le mutant fou2 porte une mutation dans le gène d'un canal à deux pores transportant probablement du potassium, du lumen de la vacuole végétale vers le compartiment cytosolique. L'analyse du protéome de fou2 a permis d'identifier une expression plus élevée de sept protéines régulées par les JA ou le stress. La découverte de l'implication d'un canal dans le phénotype de fou2 renforce l'hypothèse que les flux de cations pourraient être impliqués dans les étapes précoces de la synthèse des JA. Nous avons également étudié le protéome et la physiologie d'une feuille blessée, Pour évaluer les changements d'expression protéique en réponse à la blessure et contrôlés par les JA, nous avons quantifié l'expression de 5937 protéines chez une plante d'Arabidopsis sauvage et chez un mutant incapable de synthétiser des JA. Parmi ces 5937 protéines, nous avons identifié 99 protéines régulées par la blessure chez le type sauvage. Nous avons observé pour 65% des protéines dont l'expression protéique changeait après blessure une bonne corrélation entre la quantité de transcrits et de protéines. Plusieurs enzymes de la voie des chorismates impliquées dans la biosynthèse des acides aminés phénoliques étaient induites par les JA après blessure. Une quantification des acides aminés a montré que les niveaux d'acides aminés phénoliques augmentaient significativement après blessure. La blessure induisait aussi des changements dans l'expression de protéines impliquées dans la réponse au stress et particulièrement au stress oxydatif. Nous avons quantifié l'état réduit et oxydé du glutathion, un tripeptide qui, sous sa forme réduite, est l'antioxydant majeur des cellules. Nous avons trouvé une quantité significativement plus élevée de glutathion oxydé chez le type sauvage blessé que chez la plante aus blessée. Ce résultat suggère que la génération d'un stress oxydatif et la proportion relative de glutathions réduits et oxydés sont contrôlés par les JA après blessure. Abstract : Plants possess a family of potent fatty acid-derived wound-response and developmental regulators: the jasmonates. These compounds are derived from the tri?unsaturated fatty acid a-linolenic-acid (18:3). Addition of an oxygen molecule to 18:3 by 13-lipoxygenases (13-LOX) initiates JA biosynthesis. Actually components regulating the activation of JA biosynthesis are poorly defined. Therefore we characterized in Arabidopsis thaliana the fatty acid Qxygenation upregulated 2 (fou2) mutant, which was previously isolated in a screen for mutants with an enhanced 13-LOX activity. As a consequence of this increased 13-LOX activity, JA levels in fou2 are higher than in wild type (WT) and wounding strongly increased JA biosynthesis compared to WT. fou2 was more resistant to the fungus Botrytis cinerea and the generalist caterpillar Spodaptera littomlis, The fou2 mutant carries a missense mutation in the Two Pore Channel 1 gene (TPCJ), which encodes a vacuolar cation channel transporting probably K* into the cytosol. Patchclamp analysis of fou2 vacuolar membranes showed faster time-dependent conductivity and activation of the mutated channel at lower membrane potentials than wild-type. Proteomic analysis of fou2 leaves identified increased levels of seven biotic stress- and JA- inducible proteins. The discovery of the implication of a channel in the fou2 phenotype strenghtens the hypothesis that cation fluxes might be implicated in early steps of JA synthesis. We further concentrated on the proteome and leaf physiology in the region proximal to wounds in Arabidopsis using the WT and the aos JA-biosynthesis deficient mutant in order to find JA- induced proteins changes. We used two successive proteomic methods to assess protein changes in response to wounding Arabidopsis leaves, two dimensional electrophoresis (2DE) and linear trap quadrupole ion-trap mass spectrometry. In total 5937 proteins were quantified. We identified 99 wound-regulated proteins in the WT. Most these proteins were also wound-regulated at the transcript level showing a good correlation between transcript and protein abundance. We identified several wound-regulated enzymes involved in amino acid biosynthesis and confirmed this result by amino acid quantification. Proteins involved in stress reponses were upregulated, particularly in redox species regulation. We found a significantly higher quantity of oxidized glutathione in wounded WT relative to wounded aos leaves. This result suggests that levels of reduced glutathione are controlled by JA after wounding.
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In this article we present a method to achieve tri-dimensional contouring of macroscopic objects. A modified reference wave speckle interferometer is used in conjunction with a source of reduced coherence. The depth signal is given by the envelope of the interference signal, directly determined by the coherence length of the source. Fringes are detected in the interferogram obtained by a single shot and are detected by means of adequate filtering. With the approach based on off-axis configuration, a contour line can be extracted from a single acquisition, thus allowing to use the system in harsh environment. (C) 2009 Elsevier B.V. All rights reserved.
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Plants possess a family of potent fatty acid-derived wound-response and developmental regulators: the jasmonates. These compounds are derived from the tri-unsaturated fatty acids alpha-linolenic acid (18:3) and, in plants such as Arabidopsis thaliana and tomato, 7(Z)-, 10(Z)-, and 13(Z)-hexadecatrienoic acid (16:3). The lipoxygenase-catalyzed addition of molecular oxygen to alpha-linolenic acid initiates jasmonate synthesis by providing a 13-hydroperoxide substrate for formation of an unstable allene oxide by allene oxide synthase (AOS). This allene oxide then undergoes enzyme-guided cyclization to produce 12-oxophytodienoic acid (OPDA). These first steps take place in plastids, but further OPDA metabolism occurs in peroxisomes. OPDA has several fates, including esterification into plastid lipids and transformation into the 12-carbon prohormone jasmonic acid (JA). JA is itself a substrate for further diverse modifications, including the production of jasmonoyl-isoleucine (JA-Ile), which is a major biologically active jasmonate among a growing number of jasmonate derivatives. Each new jasmonate family member that is discovered provides another key to understanding the fine control of gene expression in immune responses; in the initiation and maintenance of long-distance signal transfer in response to wounding; in the regulation of fertility; and in the turnover, inactivation, and sequestration of jasmonates, among other processes.
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To evaluate the severity of airway pathologies, quantitative dimensioning of airways is of utmost importance. Endoscopic vision gives a projective image and thus no true scaling information can be directly deduced from it. In this article, an approach based on an interferometric setup, a low-coherence laser source and a standard rigid endoscope is presented, and applied to hollow samples measurements. More generally, the use of the low-coherence interferometric setup detailed here could be extended to any other endoscopy-related field of interest, e.g., gastroscopy, arthroscopy and other medical or industrial applications where tri-dimensional topology is required. The setup design with a multiple fibers illumination system is presented. Demonstration of the method ability to operate on biological samples is assessed through measurements on ex vivo pig bronchi.
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Retinitis pigmentosa (RP) is an inherited form of retinal degeneration that leads to progressive visual-field constriction and blindness. Although the disease manifests only in the retina, mutations in ubiquitously expressed genes associated with the tri-snRNP complex of the spliceosome have been identified in patients with dominantly inherited RP. We screened for mutations in PRPF6 (NM_012469.3), a gene on chromosome 20q13.33 encoding an essential protein for tri-snRNP assembly and stability, in 188 unrelated patients with autosomal-dominant RP and identified a missense mutation, c.2185C>T (p.Arg729Trp). This change affected a residue that is conserved from humans to yeast and cosegregated with the disease in the family in which it was identified. Lymphoblasts derived from patients with this mutation showed abnormal localization of endogenous PRPF6 within the nucleus. Specifically, this protein accumulated in the Cajal bodies, indicating a possible impairment in the tri-snRNP assembly or recycling. Expression of GFP-tagged PRPF6 in HeLa cells showed that this phenomenon depended exclusively on the mutated form of the protein. Furthermore, analysis of endogenous transcripts in cells from patients revealed intron retention for pre-mRNA bearing specific splicing signals, according to the same pattern displayed by lymphoblasts with mutations in other PRPF genes. Our results identify PRPF6 as the sixth gene involved in pre-mRNA splicing and dominant RP, corroborating the hypothesis that deficiencies in the spliceosome play an important role in the molecular pathology of this disease.
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Background: Chronic venous insufficiency (CVI) represents a major global health problem with increasing prevalence and morbidity. CVI is due to an incompetence of the venous valves, which causes venous reflux and distal venous hypertension. Several studies have focused on the replacement of diseased venous valves using xeno- and allogenic transplants, so far with moderate success due to immunologic and thromboembolic complications. Autologous cell-derived tissue-engineered venous valves (TEVVs) based on fully biodegradable scaffolds could overcome these limitations by providing non-immunogenic, non-thrombogenic constructs with remodeling and growth potential. Methods: Tri- and bicuspid venous valves (n=27) based on polyglycolic acid-poly-4-hydroxybutyrate composite scaffolds, integrated into self-expandable nitinol stents, were engineered from autologous ovine bone-marrow-derived mesenchymal stem cells (BM-MSCs) and endothelialized. After in vitro conditioning in a (flow) pulse duplicator system, the TEVVs were crimped (n=18) and experimentally delivered (n=7). The effects of crimping on the tissue-engineered constructs were investigated using histology, immunohistochemistry, scanning electron microscopy, grating interferometry (GI), and planar fluorescence reflectance imaging. Results: The generated TEVVs showed layered tissue formation with increasing collagen and glycosaminoglycan levels dependent on the duration of in vitro conditioning. After crimping no effects were found on the MSC level in scanning electron microscopy analysis, GI, histology, and extracellular matrix analysis. However, substantial endothelial cell loss was detected after the crimping procedure, which could be reduced by increasing the static conditioning phase. Conclusions: Autologous living small-diameter TEVVs can be successfully fabricated from ovine BM-MSCs using a (flow) pulse duplicator conditioning approach. These constructs hold the potential to overcome the limitations of currently used non-autologous replacement materials and may open new therapeutic concepts for the treatment of CVI in the future.
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Il existe de multiples instruments d'évaluation du fonctionnement social, de la qualité de vie ou des besoins des patients psychiatriques qui peuvent aider dans l'élaboration des stratégies de traitement. Néanmoins, nombre d'entre eux ne répondent pas toujours aux attentes des cliniciens ou des chercheurs. En réponse à ces limitations, nous avons élaboré une nouvelle échelle de mesure subjective des difficultés et du besoin d'aide, intitulée ELADEB. Sur la base d'une activité de tri de cartes, il est possible en quelques minutes de dresser le profil de difficultés des patients, et de mettre en évidence les domaines dans lesquels ils estiment avoir besoin d'une aide supplémentaire par rapport à celle qui existe peut-être déjà.
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Steady state plasma concentrations of the (L)- and (D)-enantiomers of trimipramine (TRI), desmethyltrimipramine (DTRI), 2-hydroxytrimipramine (TRIOH) and 2-hydroxydesmethyl-trimipramine (DTRIOH) were measured in 27 patients receiving between 300 and 400 mg/day racemic TRI. The patients were phenotyped with dextromethorphan and mephenytoin, and the 8-hour urinary ratios of dextromethorphan/dextrorphan, dextromethorphan/3-methoxymorphinan, and (S)-mephenytoin/(R)mephenytoin were used as markers of cytochrome P-450IID6 (CYP2D6), CYP3A4/5 and CYP2C19 activities, respectively. One patient was a CYP2D6 and one was a CYP2C19 poor metabolizer. A stereoselectivity in the metabolism of TRI has been found, with a preferential N-demethylation of (D)-TRI and a preferential hydroxylation of (L)-TRI. CYP2D6 appears to be involved in the 2-hydroxylation of (L)-TRI, (L)DTRI and (D)-DTRI, but not of (D)-TRI, as significant correlations were measured between the dextromethorphan/dextrorphan ratios and the (L)-TRI/(L)-TRIOH (r = 0.45, p = 0.019), the (L)-DTRI/(L)-DTRIOH (r = 0.47, p = 0.014), and the (D)-DTRI/(D)-DTRIOH (r = 0.51, p = 0.006), but not with the (D)-TRI/(D)-TRIOH ratios (r = 0.29, NS). CYP2C19, but not CYP2D6, appears to be involved in the demethylation pathway, with a stereoselectivity toward the (D)-enantiomer of TRI, as a significant positive correlation was calculated between the mephenytoin (S)/(R) ratios and the concentrations to dose-to-weight ratios of (D)-TRI (r = 0.69, p = 0.00006). CYP3A4/5 appears to be involved in the metabolism of (L)-TRI to a presently not determined metabolite. The CYP2D6 poor metabolizer had the highest (L)-DTRI and (D)-DTRI concentrations to dose-to-weight ratios, and the CYP2C19 poor metabolizer had the highest (L)-TRI and (D)-TRI concentrations to dose-to-weight ratios of the group.
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La quantité de déchets ménagers et industriels ne cesse d'augmenter. Le tri sélectif des ordures est devenu systématique dans beaucoup de municipalités européennes et le compostage industriel des matières organiques par maturation accélérée en système clos a acquis une place prépondérante. Cependant, ce type de compostage nécessite une forte concentration de divers micro-organismes. Il en résulte un risque microbiologique aéroporté encore mal évalué pour les travailleurs exposés à ces atmosphères chargées en bioaérosols (bactéries, champignons et endotoxines en suspension dans l'air). [Auteur]