89 resultados para Esplosione, ATEX, Rischio, Zona, Gas, Polveri


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A patent foramen ovale (PFO), present in ∼40% of the general population, is a potential source of right-to-left shunt that can impair pulmonary gas exchange efficiency [i.e., increase the alveolar-to-arterial Po2 difference (A-aDO2)]. Prior studies investigating human acclimatization to high-altitude with A-aDO2 as a key parameter have not investigated differences between subjects with (PFO+) or without a PFO (PFO-). We hypothesized that in PFO+ subjects A-aDO2 would not improve (i.e., decrease) after acclimatization to high altitude compared with PFO- subjects. Twenty-one (11 PFO+) healthy sea-level residents were studied at rest and during cycle ergometer exercise at the highest iso-workload achieved at sea level (SL), after acute transport to 5,260 m (ALT1), and again at 5,260 m after 16 days of high-altitude acclimatization (ALT16). In contrast to PFO- subjects, PFO+ subjects had 1) no improvement in A-aDO2 at rest and during exercise at ALT16 compared with ALT1, 2) no significant increase in resting alveolar ventilation, or alveolar Po2, at ALT16 compared with ALT1, and consequently had 3) an increased arterial Pco2 and decreased arterial Po2 and arterial O2 saturation at rest at ALT16. Furthermore, PFO+ subjects had an increased incidence of acute mountain sickness (AMS) at ALT1 concomitant with significantly lower peripheral O2 saturation (SpO2). These data suggest that PFO+ subjects have increased susceptibility to AMS when not taking prophylactic treatments, that right-to-left shunt through a PFO impairs pulmonary gas exchange efficiency even after acclimatization to high altitude, and that PFO+ subjects have blunted ventilatory acclimatization after 16 days at altitude compared with PFO- subjects.

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The objective of this work was to combine the advantages of the dried blood spot (DBS) sampling process with the highly sensitive and selective negative-ion chemical ionization tandem mass spectrometry (NICI-MS-MS) to analyze for recent antidepressants including fluoxetine, norfluoxetine, reboxetine, and paroxetine from micro whole blood samples (i.e., 10 microL). Before analysis, DBS samples were punched out, and antidepressants were simultaneously extracted and derivatized in a single step by use of pentafluoropropionic acid anhydride and 0.02% triethylamine in butyl chloride for 30 min at 60 degrees C under ultrasonication. Derivatives were then separated on a gas chromatograph coupled with a triple-quadrupole mass spectrometer operating in negative selected reaction monitoring mode for a total run time of 5 min. To establish the validity of the method, trueness, precision, and selectivity were determined on the basis of the guidelines of the "Société Française des Sciences et des Techniques Pharmaceutiques" (SFSTP). The assay was found to be linear in the concentration ranges 1 to 500 ng mL(-1) for fluoxetine and norfluoxetine and 20 to 500 ng mL(-1) for reboxetine and paroxetine. Despite the small sampling volume, the limit of detection was estimated at 20 pg mL(-1) for all the analytes. The stability of DBS was also evaluated at -20 degrees C, 4 degrees C, 25 degrees C, and 40 degrees C for up to 30 days. Furthermore, the method was successfully applied to a pharmacokinetic investigation performed on a healthy volunteer after oral administration of a single 40-mg dose of fluoxetine. Thus, this validated DBS method combines an extractive-derivative single step with a fast and sensitive GC-NICI-MS-MS technique. Using microliter blood samples, this procedure offers a patient-friendly tool in many biomedical fields such as checking treatment adherence, therapeutic drug monitoring, toxicological analyses, or pharmacokinetic studies.

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A headspace-gas chromatography-tandem mass spectrometry (HS-GC-MS/MS) method for the trace measurement of perfluorocarbon compounds (PFCs) in blood was developed. Due to oxygen carrying capabilities of PFCs, application to doping and sports misuse is speculated. This study was therefore extended to perform validation methods for F-tert-butylcyclohexane (Oxycyte(®)), perfluoro(methyldecalin) (PFMD) and perfluorodecalin (PFD). The limit of detection of these compounds was established and found to be 1.2µg/mL blood for F-tert-butylcyclohexane, 4.9µg/mL blood for PFMD and 9.6µg/mL blood for PFD. The limit of quantification was assumed to be 12µg/mL blood (F-tert-butylcyclohexane), 48µg/mL blood (PFMD) and 96µg/mL blood (PFD). HS-GC-MS/MS technique allows detection from 1000 to 10,000 times lower than the estimated required dose to ensure a biological effect for the investigated PFCs. Thus, this technique could be used to identify a PFC misuse several hours, maybe days, after the injection or the sporting event. Clinical trials with those compounds are still required to evaluate the validation parameters with the calculated estimations.

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Very large molecular systems can be calculated with the so called CNDOL approximate Hamiltonians that have been developed by avoiding oversimplifications and only using a priori parameters and formulas from the simpler NDO methods. A new diagonal monoelectronic term named CNDOL/21 shows great consistency and easier SCF convergence when used together with an appropriate function for charge repulsion energies that is derived from traditional formulas. It is possible to obtain a priori molecular orbitals and electron excitation properties after the configuration interaction of single excited determinants with reliability, maintaining interpretative possibilities even being a simplified Hamiltonian. Tests with some unequivocal gas phase maxima of simple molecules (benzene, furfural, acetaldehyde, hexyl alcohol, methyl amine, 2,5 dimethyl 2,4 hexadiene, and ethyl sulfide) ratify the general quality of this approach in comparison with other methods. The calculation of large systems as porphine in gas phase and a model of the complete retinal binding pocket in rhodopsin with 622 basis functions on 280 atoms at the quantum mechanical level show reliability leading to a resulting first allowed transition in 483 nm, very similar to the known experimental value of 500 nm of "dark state." In this very important case, our model gives a central role in this excitation to a charge transfer from the neighboring Glu(-) counterion to the retinaldehyde polyene chain. Tests with gas phase maxima of some important molecules corroborate the reliability of CNDOL/2 Hamiltonians.

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Depuis 2007, le vaccin vivant atténué contre le zona dispose d'une autorisation de mise sur le marché au niveau européen. Fin 2015-début 2016, il devrait enfin être disponible en France. Cet article répond à vos interrogations concernant son intérêt, son efficacité, sa tolérance et ses bénéfices pour la société, dans la prévention du zona et d'une de ses complications les plus fréquentes et la plus invalidante : les douleurs post-zostériennes.

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CONTEXT: A vaccination against herpes zoster and its complication is available in France since June 2015. Its exact benefit for public health is still controversial and its level of protection is not optimal. All those reasons seem to suggest a low acceptation rate from general practitioners. OBJECTIVE: To evaluate the effectiveness, the safety, and the cost/benefit ratio of the vaccination against herpes zoster in people aged 50 year or over. DOCUMENTARY SOURCE: Systematic review in Medline and PubMed with research by key words: "herpes zoster vaccine", "zoster vaccine" and "post herpetic neuralgia vaccine". SELECTION OF STUDIES: Randomized and observational studies published in English and French language have been selected by two readers. RESULTS: On 1886 articles identified, 62 studies were included in this systematic review of which 21 randomized trials, 21 observational studies, and 17 medico-economic studies concerned the unadjuvanted vaccine. Considered studies showed an effectiveness of 50% against herpes zoster and 60% on post-herpetic neuralgia incidence of the unadjuvanted vaccine. Five randomized controlled studies were identified for the adjuvanted vaccine. The overall effectiveness of this vaccine was > 90% whatever the age of subjects including those over age 70 and 80. The medico-economic studies conducted in many countries have shown that vaccine policies were beneficial in individuals aged 60 years or over. LIMITATION OF THE WORK: Most of data of effectiveness, and tolerance result from 2 large controlled studies only (SPS and ZEST) for the unadjuvanted vaccine and only one for the adjuvanted vaccine. CONCLUSION: Despite controversy and few uncertainties, the vaccine significantly reduces herpes zoster and its complication incidence. In terms of public health objectives, it reduces the burden of the disease and has a positive medico-economic impact. Preliminary data concerning the adjuvanted vaccine, whilst very promising, are still too limited. Up to now, no group of people with particularly high risk of herpes zoster-related complication who will beneficiate the most of the vaccination has been identified yet and only an age criteria has been considered for the recommendation.

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Depuis 2006, le vaccin vivant atténué contre le zona dispose d'une autorisation de mise sur le marché au niveau européen. Depuis le 15 juin 2015, il est enfin disponible en France au prix de 127,24 euro et remboursé à 30 % par l'assurance maladie. Cet article répond à vos interrogations concernant son intérêt, son efficacité, sa tolérance et ses bénéfices pour la société, dans la prévention du zona et d'une de ses complications les plus fréquentes et la plus invalidante, les douleurs post-zostériennes. Since 2006, the live attenuated vaccine against shingles has had market authorisation in the European Union. Since June 15th 2015, it is available in France for the price of 127.24 euro and will be reimbursed by the National Health Insurance System. This article answers your questions about its interest, efficacy, tolerance and benefits to society in the prevention of shingles and one of its the most frequent and most disabling complications: post-herpetic neuralgia.

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Depuis 2007, le vaccin vivant atténué contre le zona, dispose d'une autorisation de mise sur le marché au niveau européenne. Il sera enfin bientôt disponible en Suisse. Cet article répond à vos interrogations concernant son intérêt, son efficacité, sa tolérance et ses bénéfices pour la société, dans la prévention du zona et d'une de ses complications les plus fréquentes et la plus invalidante les douleurs post-zostériennes.

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Initiated within the first 72hours of the rash, prescribing antiviral drugs reduces both acute neuralgia (AN) and later complications and especially postherpetic neuralgia (PHN). But their analgesic as well as preventative effect on AN and PHN is modest. Combination with analgesic drugs is more often needed for pain management. However, the pharmacological management of pain, in the context of old patients' frailty, co-morbidities and often polypharmacy, must be carefully considered. Based on analyses of the evidences from the literature, this review presents the therapeutic options we have at one's disposal and proposes a stepwise management for both AN and PHN specifically designed for aged population.

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Vaccination aims at generating memory immune responses able to protect individuals against pathogenic challenges over long periods of time. Subunit vaccine formulations based on safe, but poorly immunogenic, antigenic entities must be combined with adjuvant molecules to make them efficient against infections. We have previously shown that gas-filled microbubbles (MB) are potent antigen-delivery systems. This study compares the ability of various ovalbumin-associated MB (OVA-MB) formulations to induce antigen-specific memory immune responses and evaluates long-term protection toward bacterial infections. When initially testing dendritic cells reactivity to MB constituents, palmitic acid exhibited the highest degree of activation. Subcutaneous immunization of naïve wild-type mice with the OVA-MB formulation comprising the highest palmitic acid content and devoid of PEG2000 was found to trigger the more pronounced Th1-type response, as reflected by robust IFN-γ and IL-2 production. Both T cell and antibody responses persisted for at least 6 months after immunization. At that time, systemic infection with OVA-expressing Listeria monocytgenes was performed. Partial protection of vaccinated mice was demonstrated by reduction of the bacterial load in both the spleen and liver. We conclude that antigen-bound MB exhibit promising properties as a vaccine candidate ensuring prolonged maintenance of protective immunity.

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Uromodulin is the most abundant protein in the urine. It is exclusively produced by renal epithelial cells and it plays key roles in kidney function and disease. Uromodulin mainly exerts its function as an extracellular matrix whose assembly depends on a conserved, specific proteolytic cleavage leading to conformational activation of a Zona Pellucida (ZP) polymerisation domain. Through a comprehensive approach, including extensive characterisation of uromodulin processing in cellular models and in specific knock-out mice, we demonstrate that the membrane-bound serine protease hepsin is the enzyme responsible for the physiological cleavage of uromodulin. Our findings define a key aspect of uromodulin biology and identify the first in vivo substrate of hepsin. The identification of hepsin as the first protease involved in the release of a ZP domain protein is likely relevant for other members of this protein family, including several extracellular proteins, as egg coat proteins and inner ear tectorins.