Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Isotopes have been widely used for source identification since the early twentieth century. Recent advances in analytical techniques have increased the precision and the accuracy of isotope analysis. As a result, the use of isotopes has spread to several fields (e.g., ecology, food chemistry, archaeology, environmental health and pollution, and forensic sciences). This review examines the principal uses of stable-isotope analyses for tracing origins or sources, along with statistical methods employed for data interpretation, in recent papers (2007―09) dealing essentially with food authentication, ecology, environmental pollution and other applications, including geology, police forensics, hydrology and archaeometry. The main elements analyzed were H, C, N, O, S, Sr and Pb. For isotope-data interpretation, statistical methods appear to depend essentially on the field, the objectives of the study and the number of parameters. They were not often stated explicitly because the studies were exploratory and aimed primarily at assessing the relevance of the analytical techniques used to identify sources. We critically discuss the adequacy of these methods.
ISSN: 0165-9936

hal-00687383
https://hal.archives-ouvertes.fr/hal-00687383

Éditeur(s) : HAL CCSD
Résumé : Background Acute splenic sequestration is one of the major clinical forms of sickle cell disease. This potentially life-threatening complication is defined by a rapid sequestration of sickle red blood cells in the spleen. Approximately 30% of young patients will develop this complication and 49% of them will have recurrences. Methods The decision tree method is a statistical method that can act as a medical decision tool in the case of a complex biological problem. The decision tree method is used here to determine the variables involved in the severity and recurrence of acute splenic sequestration crises. Results A prior decision tree shows that platelet level, variation in spleen size, patient age and hygrometry also called relative humidity define acute splenic sequestration severity. A second one shows that spleen size variation, atmospheric pressure and patient age define recurrence. Conclusions For the first time, biological and environmental parameters are combined to discover some interesting rules which can lead to more accurate evaluations of acute splenic sequestration severity and recurrence. Thus, this method provides a sharp diagnostic tool which could improve medical treatment for better patient care.
https://hal.archives-ouvertes.fr/hal-00201460

hal-00201460
https://hal.archives-ouvertes.fr/hal-00201460
https://hal.archives-ouvertes.fr/hal-00201460v2/document
https://hal.archives-ouvertes.fr/hal-00201460/file/DT_Marianne_v2.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The present study investigated cerebral and muscle hemoglobin oxygen saturation (tissue oxygen index, TOI) in children with sickle cell anemia (SS), sickle cell hemoglobin C disease (SC) and healthy children (AA). TOI was measured by near-infrared spectroscopy (NIRS) and spectral analysis of the TOI variability was used to assess flowmotion and vasomotion. Arterial oxyhemoglobin saturation (SpO2), hemorheological and hematological parameters were also measured in SS and SC children. Both TOI were lower in SS compared to both AA and SC children, with SC exhibiting lower values than AA children. Cerebral vasomotion expressed in absolute values was enhanced in SS compared to AA and SC children. Muscle vasomotion did not differ between the three groups. Hematocrit, SpO2 and red blood cell deformability were positively associated with cerebral TOI in SS children. We demonstrated that 1) cerebral and muscle TOI were markedly decreased in SS children while the decrease of TOI was milder in SC children, 2) cerebral TOI level was associated with several biological markers in SS children only and 3) cerebral vasomotion was enhanced in SS, possibly to counterbalance the effects of chronic cerebral hypoxia.
ISSN: 1079-9796

inserm-01519106
http://www.hal.inserm.fr/inserm-01519106
http://www.hal.inserm.fr/inserm-01519106/document
http://www.hal.inserm.fr/inserm-01519106/file/2017%2C%20Charlot%20-%20Cerebral%20and%20muscle%20microvascular%20oxygenation%20in%20children%20with%20sickle%20celle%20disease.pdf
DOI : 10.1016/j.bcmd.2017.03.015

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
Intestinal absorption and brain permeation constitute key parameters of toxicokinetics for pesticides, conditioning their toxicity, including neurotoxicity. However, they remain poorly characterized in humans. The present study was therefore designed to evaluate human intestine and brain permeation for a large set of pesticides (n = 338) belonging to various chemical classes, using an in silico graphical BOILED-Egg/SwissADME online method based on lipophilicity and polarity that was initially developed for drugs. A high percentage of the pesticides (81.4%) was predicted to exhibit high intestinal absorption, with a high accuracy (96%), whereas a lower, but substantial, percentage (38.5%) displayed brain permeation. Among the pesticide classes, organochlorines (n = 30) constitute the class with the lowest percentage of intestine-permeant members (40%), whereas that of the organophosphorus compounds (n = 99) has the lowest percentage of brain-permeant chemicals (9%). The predictions of the permeations for the pesticides were additionally shown to be significantly associated with various molecular descriptors well-known to discriminate between permeant and non-permeant drugs. Overall, our in silico data suggest that human exposure to pesticides through the oral way is likely to result in an intake of these dietary contaminants for most of them and brain permeation for some of them, thus supporting the idea that they have toxic effects on human health, including neurotoxic effects.
ISSN: 1660-4601

hal-01560242
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01560242
PUBMED : 28665355
DOI : 10.3390/ijerph14070708

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
The levels and duration of physical activity that can be considered as completely safe in patients with sickle cell anemia (SCA) is unknown. The present study compared the hemorheological and hematological profile, cell density distribution and basic biochemistry between a group of 17 patients with SCA and 21 healthy subjects before and after a 20 min duration submaximal cycling exercise at the same absolute workload. Blood was sampled at rest and 3 min after the end of exercise for measurement of biological parameters. Exercise did not affect the hematocrit and blood viscosity in the two groups. Plasma viscosity was not different between the two groups at rest and similarly increased with exercise. The proportion of intermediary dense cells (with density between 1.11 and 1.12 g/ml) decreased with exercise in the SCA group resulting in an increase in the proportion of red blood cells with a density > 1.12 g/ml. No change was observed in the control group. The present study suggests that mild-moderate exercise is not very harmful for SCA patients. The hemorheological and hematological changes very mild, except for the formation of dense cells but no clinically significant signs of medical complication were present in any of the patients.
ISSN: 0007-1048

hal-00640629
https://hal.archives-ouvertes.fr/hal-00640629
https://hal.archives-ouvertes.fr/hal-00640629/document
https://hal.archives-ouvertes.fr/hal-00640629/file/PEER_stage2_10.1111%252Fj.1365-2141.2011.08728.x.pdf
DOI : 10.1111/j.1365-2141.2011.08728.x

Résumé : Les pathologies inflammatoires démyélinisantes primitives du système nerveux central (SNC) sont dominées par deux entités : la sclérose en plaques (SEP) et la neuromyélite optique (NMO). Ces deux pathologies se différencient par : 1. leur phénotype, la NMO se caractérisant par une myélite extensive dans le plan transversal et longitudinal et peu de lésions encéphaliques initiales ; 2. leur sévérité, le pronostic de la NMO étant moins bon que celui de la SEP ; 3. leur mécanisme immunologique, puisque l’immunité humorale domine nettement dans la NMO, cette pathologie répondant peu ou pas aux traitementshabituellement prescrits dans la SEP. Un anticorps sérique (IgG-NMO) a été retrouvé chez les patients atteints de NMO avec une sensibilité de 50-70% et une spécificité de 90-100%. Cet anticorps a pour cible le principal canal hydrique du SNC, l’aquaporine-4 (AQP4), qui se situe principalement sur les pieds astrocytaires jalonnant la barrière hémato-encéphalique. La SEP est relativement familière des neurologues car décrite sur le plan épidémiologique et dans son histoire naturelle depuis plus d’un siècle à travers de larges séries réalisées parfois en population générale. Son approche thérapeutique progresse suite à des essais contrôlés qui s’accumulent depuis maintenant près de 20 ans. Toutefois, la majorité des travaux ont été effectués chez les populations Caucasiennes en raison de sa plus grande fréquence dans ces populations. A l’inverse, la NMO garde encore un relatif mystère à cause de sa relative rareté, l’établissement très récent de critères diagnostiques et une physiopathologie très récemment éclaircie par la découverte de l’IgG-NMO qui a indiscutablement suscité un regain d’intérêt de cette affection. Ainsi, son incidence est quasiment inconnue de même que sa susceptibilité génétique. La progression du handicap de la NMO qu’il soit visuel ou moteur à l’évidence sévère, ne repose toujours pas sur des chiffres précis, la description des lésions neuroradiologiques reste encore très embryonnaire. Enfin, même s’il existe un consensus pour traiter énergiquement les poussées de NMO et les espacer, il n’existe quasiment aucune étude prospective.
Introduction: Aim of the study is to describe épidemiology, phenotype and treatment of demyelinating inflammatory diseases of the central nervous system (CNS) namely multiple sclerosis (MS) and neuromyelitis optica (NMO) in French West Indies.Epidemiology: MS emerged in the French West Indian (FWI) population with an incidence of 1.27/100 000 (CI 95%: 1.16-1.38) for the period 1992-2007 while incidence of NMO remained stable at 0.19/100,000 (CI 95%: 0.15–0.23). Both migration in Metropolitean France (MF) and decrease of sun exposure were risk factors for MS acquisition in FWI. Phenotype and treatment of NMO: NMO is a very rapidly disabling disease with median times to reach DSS 3, 6 and 8 of one year, 8 years and 22 years respectively. However, treatment by plasma exchanges were shown to reduce sequellae of NMO attacks ; mitoxantrone and rituximab reduced significantly annualized relapse rate (ARR) from 1.7 to 0.29 (p<10-4) and from 1,34 to 0,56 (p=0.0005) respectively, improving dramatically natural course of NMO.Phenotype and treatment of MS: Absence of Migration in MF in MS patients was found to be the strongest independent predictive factor of disability progression to DSS 6 (hazard ratio, 2.59; p=0.0002); beside short time to DSS3 (p=0.005), later age at onset (p=0.005), and multi-symptomatic onset (p=0.03). Treatment of MS by interferon beta-1 had a moderate impact in MS while natalizimab proved to be highly effective by reducing drastically ARR and inflammatory parameters on magnetic resonance imaging. Conclusion: Spectrum of demyelinating inflammatory disorders of CNS has reversed in French West Indies with overrepresentation of MS. Agressive therapy is needed to improve prognosis of NMO. Rapidly increasing of its incidence makes MS a new public health problem in French West Indies.

http://www.theses.fr/2012AGUY0511/document