RESUMEN
Interlaboratory evaluations of Mucorales qPCR assays were developed to assess the reproducibility and performance of methods currently used. The participants comprised 12 laboratories from French university hospitals (nine of them participating in the Modimucor study) and 11 laboratories participating in the Fungal PCR Initiative. For panel 1, three sera were each spiked with DNA from three different species (Rhizomucor pusillus, Lichtheimia corymbifera, Rhizopus oryzae). For panel 2, six sera with three concentrations of R. pusillus and L. corymbifera (1, 10, and 100 genomes/ml) were prepared. Each panel included a blind negative-control serum. A form was distributed with each panel to collect results and required technical information, including DNA extraction method, sample volume used, DNA elution volume, qPCR method, qPCR template input volume, qPCR total reaction volume, qPCR platform, and qPCR reagents used. For panel 1, assessing 18 different protocols, qualitative results (positive or negative) were correct in 97% of cases (70/72). A very low interlaboratory variability in Cq values (SD = 1.89 cycles) were observed. For panel 2 assessing 26 different protocols, the detection rates were high (77-100%) for 5/6 of spiked serum. There was a significant association between the qPCR platform and performance. However, certain technical steps and optimal combinations of factors may also impact performance. The good reproducibility and performance demonstrated in this study support the use of Mucorales qPCR as part of the diagnostic strategy for mucormycosis.
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Técnicas de Laboratorio Clínico/normas , ADN de Hongos/genética , Técnicas de Diagnóstico Molecular/normas , Mucorales/genética , Mucormicosis/sangre , Mucormicosis/diagnóstico , Reacción en Cadena en Tiempo Real de la Polimerasa/normas , Técnicas de Laboratorio Clínico/instrumentación , Técnicas de Laboratorio Clínico/métodos , Francia , Hospitales Universitarios/estadística & datos numéricos , Humanos , Variaciones Dependientes del Observador , Reproducibilidad de los ResultadosRESUMEN
In the long-term after atmospheric deposit onto a forest ecosystem, Cs-137 becomes incorporated into the biogeochemical cycle of stable elements and progressively reaches a quasi-equilibrium state. This study aimed at determining to what extent Cs-137 activity distribution in tree vegetation could be predicted from that of stable caesium (Cs-133) and potassium (K), which are known to be stable chemical analogues and competitors for Cs-137 intake in tree organs. Field campaigns that focused on beech trees (Fagus sylvatica L.) were conducted in 2021 in three French forest stands with contrasted characteristics regarding either the contribution of global vs. Chornobyl fallouts, soil or climatic conditions. Decades after Cs-137 fallouts, it was found that more than 80% of the total radioactive inventory in the system remained confined in the top 20 cm mineral layers, while organic layers and beech vegetation (including roots) contributed each to less than 1.5%. The enhanced downward migration of Cs-137 in cambisol than podzol forest sites was presumably due to migration of clay particles and bioturbation. The distribution of Cs-137 and Cs-133 inventories in beech trees was very similar among sites but differed from that of K due a higher accumulation of Cs isotopes in roots (40-50% vs. < 25% for K). The aggregated transfer factor (Tag) of Cs-137 calculated for aerial beech organs were all lower than those reported in literature more than 20 years ago, this suggesting a decrease of bioavailability in soil due to ageing processes. Regarding their variability, Tags were generally lower by a factor 5 at the cambisol site, which was fairly well explained by a much higher value of RIP (radiocesium immobilisation potential). Cs-137 concentrations in trees organs normalized by the soil exchangeable fractions were linearly correlated to those of Cs-133 and the best fit was found for the linear regression model without intercept indicating that no more contribution of the foliar uptake could be observed on long term. Provided that the vertical distribution of caesium concentrations and fine root density are properly measured or estimated, Cs-133 was shown to be a much better proxy than K to estimate the root transfer of Cs-137.
Asunto(s)
Radioisótopos de Cesio , Fagus , Bosques , Monitoreo de Radiación , Contaminantes Radiactivos del Suelo , Fagus/metabolismo , Fagus/química , Contaminantes Radiactivos del Suelo/análisis , Contaminantes Radiactivos del Suelo/metabolismo , Radioisótopos de Cesio/análisis , Radioisótopos de Cesio/metabolismo , Francia , Árboles/química , Potasio/análisis , Potasio/metabolismo , Accidente Nuclear de ChernóbilRESUMEN
Due to large outbreaks observed worldwide, Candida auris has emerged as a major threat to healthcare facilities. To prevent these phenomena, a systematic screening should be performed in patients transferred from regions where the pathogen is highly endemic. In this study, we recorded and analyzed French mycologists' current knowledge and practice regarding C. auris screening and diagnosis. Thirty-six centers answered an online questionnaire. Only 11 (30.6 %) participants were aware of any systematic screening for C. auris for patients admitted to their hospital. In the case of post-admission screening, axillae/groins (n = 21), nares (n = 7), rectum (n = 9), and mouth (n = 6) alone or various combinations were the body sites the most frequently sampled. Only six centers (8.3 %) reported using a commercially available plate allowing the differentiation of C. auris colonies from that of other Candida species, while five laboratories (13.8 %) had implemented a C. auris-specific qPCR. Considering the potential impact on infected patients and the risk of disorganization in the care of patients, it is crucial to remember to biologists and clinicians the utmost importance of systematic screening on admission.
RESUMEN
This paper compares the Morris, Spearman and Sobol' methods of sensitivity analysis in radiological risk assessment. The determination of the most influential parameters on model with regards to the propagation of their uncertainties to output variables, is of greatest interest. This study aims to determine the relative importance of parameters uncertainties on the dose calculation uncertainty in the framework of a scenario of routine discharges discussed in the context of an IAEA working group. The scenario considers atmospheric and liquid discharges of three different types of radionuclides (14C, tritium as HTO and 110mAg) from a nuclear power plant located by the side of a river. It is concluded that the most reliable and practical method according to the ability of ranking influential parameters and the easiness of its application is the Spearman method. As key result, the three first influential variables for annual total dose for all pathways and all radionuclides were the water dissolved inorganic carbon concentration, the volatilisation rate constant and the soil layer solid liquid distribution in 14C.
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Plantas de Energía Nuclear , Monitoreo de RadiaciónRESUMEN
Competition between background microflora and microbial pathogens raises questions about the application of predictive microbiology in situ, i.e., in non-sterile naturally contaminated foods. In this article, we present a review of the models developed in predictive microbiology to describe interactions between microflora in foods, with a special focus on two approaches: one based on the Jameson effect (simultaneous deceleration of all microbial populations) and one based on the Lotka-Volterra competition model. As an illustration of the potential of these models, we propose various modeling examples in estimation and in prediction of microbial growth curves, all related to the behavior of Listeria monocytogenes with lactic acid bacteria in three pork meat products (fresh pork meat and two types of diced bacon).
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Microbiología de Alimentos/métodos , Lactobacillus/crecimiento & desarrollo , Listeria monocytogenes/crecimiento & desarrollo , Productos de la Carne/microbiología , Modelos Biológicos , Animales , Recuento de Colonia Microbiana , PorcinosRESUMEN
Models on Clostridium perfringens growth which have been published to date have all been deterministic. A probabilistic model describing growth under non-isothermal conditions was thus proposed for predicting C. perfringens growth in beef-in-sauce products cooked and distributed in a French hospital. Model parameters were estimated from different types of data from various studies. A Bayesian approach was proposed to model the overall uncertainty regarding parameters and potential variability on the 'work to be done' (h(0)) during the germination, outgrowth and lag phase. Three models which differed according to their description of this parameter h(0) were tested. The model with inter-curve variability on h(0) was found to be the best one, on the basis of goodness-of-fit assessment and validation with literature data on results obtained under non-isothermal conditions. This model was used in two-dimensional Monte Carlo simulations to predict C. perfringens growth throughout the preparation of beef-in-sauce products, using temperature profiles recorded in a hospital kitchen. The median predicted growth was 7.8×10(-2) log(10) cfu·g(-1) (95% credibility interval [2.4×10(-2), 0.8]) despite the fact that for more than 50% of the registered temperature profiles cooling steps were longer than those required by French regulations.
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Clostridium perfringens/crecimiento & desarrollo , Conservación de Alimentos/métodos , Productos de la Carne/microbiología , Modelos Biológicos , Teorema de Bayes , Recuento de Colonia Microbiana , Seguridad de Productos para el Consumidor , Culinaria/métodos , Manipulación de Alimentos/métodos , Humanos , Cinética , Método de Montecarlo , Valor Predictivo de las Pruebas , TemperaturaRESUMEN
INTRODUCTION: Rhino-orbital-aspergillosis (ROA) is a rare but serious disease in immunocompetent patients. Diagnosis is often delayed due to the absence of specific clinical symptoms. We describe the case of a patient who presented initially with ROA which spread progressively to the right ethmoid-sphenoid sinuses and then to the brain. OBSERVATION: A 61-year-old patient with a history of well-controlled diabetes presented with a sudden severe decrease in right visual acuity. Cerebral MRI showed the presence of an infiltrate in the right orbital apex extending to the homolateral cavernous sinus without any cerebral involvement. A diagnosis of right orbital myositis was made and corticosteroid therapy was started. His symptoms worsened progressively leading to quasi-blindness. A new MRI showed the development of right sphenoid-ethmoid osteolytic lesions. A fungal aetiology was suspected and tests for fungal biomarkers found a ß-(1-3)-D-glucan level of 99pg/ml but negative galactomannan. An ethmoid biopsy was performed for histological and mycological investigations, including the detection of Aspergillus DNA by qPCR. qPCR was positive and culture resulted in the isolation of multi-sensitive Aspergillus fumigatus. Treatment was initiated with voriconazole. Due to persistence of blindness and the appearance of a lesion extending to the right frontal lobe, surgical excision was performed followed by antifungal treatment for a total duration of 1year. The patient is currently stable, but has persistence of blindness in the right eye. CONCLUSION: Invasive ROA is a rare but serious disease in immunocompetent patients which should be evoked in the differential diagnosis of a tumour or vasculitis. Early diagnosis is essential for optimal management.
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Aspergilosis/diagnóstico , Infecciones Fúngicas del Sistema Nervioso Central/diagnóstico , Infecciones Fúngicas del Ojo/microbiología , Inmunocompetencia , Infecciones Fúngicas Invasoras/diagnóstico , Rinitis/microbiología , Antifúngicos/uso terapéutico , Aspergilosis/tratamiento farmacológico , Aspergilosis/microbiología , Aspergillus fumigatus/aislamiento & purificación , Ceguera/diagnóstico , Ceguera/microbiología , Infecciones Fúngicas del Sistema Nervioso Central/complicaciones , Infecciones Fúngicas del Sistema Nervioso Central/tratamiento farmacológico , Infecciones Fúngicas del Sistema Nervioso Central/microbiología , Complicaciones de la Diabetes/tratamiento farmacológico , Complicaciones de la Diabetes/microbiología , Infecciones Fúngicas del Ojo/complicaciones , Infecciones Fúngicas del Ojo/diagnóstico , Infecciones Fúngicas del Ojo/tratamiento farmacológico , Humanos , Infecciones Fúngicas Invasoras/tratamiento farmacológico , Infecciones Fúngicas Invasoras/microbiología , Masculino , Persona de Mediana Edad , Neuroaspergilosis/complicaciones , Neuroaspergilosis/diagnóstico , Neuroaspergilosis/tratamiento farmacológico , Neuroaspergilosis/microbiología , Enfermedades Orbitales/diagnóstico , Enfermedades Orbitales/tratamiento farmacológico , Enfermedades Orbitales/microbiología , Rinitis/complicaciones , Rinitis/diagnóstico , Rinitis/tratamiento farmacológico , Voriconazol/uso terapéuticoRESUMEN
A quantitative risk assessment for Escherichia coli O157:H7 in frozen ground beef patties consumed by children under 10 years of age in French households was conducted by a national study group describing an outbreak which occurred in France in 2005. Our exposure assessment model incorporates results from French surveys on consumption frequency of ground beef patties, serving size and consumption preference, microbial destruction experiments and microbial counts on patties sampled from the industrial batch which were responsible for the outbreak. Two different exposure models were proposed, respectively for children under the age of 5 and for children between 5 and 10 years. For each of these two age groups, a single-hit dose-response model was proposed to describe the probability of hemolytic and uremic syndrome (HUS) as a function of the ingested dose. For each group, the single parameter of this model was estimated by Bayesian inference, using the results of the exposure assessment and the epidemiological data collected during the outbreak. Results show that children under 5 years of age are roughly 5 times more susceptible to the pathogen than children over 5 years. Exposure and dose-response models were used in a scenario analysis in order to validate the use of the model and to propose appropriate guidelines in order to prevent new outbreaks. The impact of the cooking preference was evaluated, showing that only a well-done cooking notably reduces the HUS risk, without annulling it. For each age group, a relation between the mean individual HUS risk per serving and the contamination level in a ground beef batch was proposed, as a tool to help French risk managers.
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Escherichia coli O157/crecimiento & desarrollo , Contaminación de Alimentos/análisis , Manipulación de Alimentos/métodos , Alimentos Congelados/microbiología , Productos de la Carne/microbiología , Medición de Riesgo , Factores de Edad , Animales , Teorema de Bayes , Bovinos , Niño , Preescolar , Recuento de Colonia Microbiana , Culinaria , Brotes de Enfermedades , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/etiología , Infecciones por Escherichia coli/microbiología , Femenino , Enfermedades Transmitidas por los Alimentos/epidemiología , Francia/epidemiología , Síndrome Hemolítico-Urémico/epidemiología , Síndrome Hemolítico-Urémico/etiología , Síndrome Hemolítico-Urémico/microbiología , Humanos , MasculinoRESUMEN
An attempt to use a Bayesian approach to model variability and uncertainty separately in microbial growth in a risk assessment is presented. It was conducted within the framework of a French project aiming at assessing the exposure to Listeria monocytogenes in cold-smoked salmon. The chosen model describes the effect of time and temperature on bacterial growth. A Bayesian approach close to the one proposed by Pouillot et al. [Int. J. Food Microbiol. 81 (2003) 87] is used to estimate the variability and uncertainty of growth parameters from both literature data and data experimentally acquired during the project. Variability between strains and between products is taken into account. The growth of the food flora of cold-smoked salmon is also modelled by the same method. The results obtained for both models are used to predict the simultaneous growth of L. monocytogenes and food flora in cold-smoked salmon with a competitive model, expressing variability and uncertainty through a second-order Monte Carlo simulation.
Asunto(s)
Teorema de Bayes , Seguridad de Productos para el Consumidor , Listeria monocytogenes/crecimiento & desarrollo , Modelos Biológicos , Salmón/microbiología , Animales , Recuento de Colonia Microbiana , Humanos , Método de Montecarlo , Valor Predictivo de las Pruebas , Medición de Riesgo , Temperatura , Factores de TiempoRESUMEN
Salting and smoking are ancient processes for fish preservation. The effects of salt and phenolic smoke compounds on the growth rate of L. monocytogenes in cold-smoked salmon were investigated through physico-chemical analyses, challenge tests on surface of cold-smoked salmon at 4 degrees C and 8 degrees C, and a survey of the literature. Estimated growth rates were compared to predictions of existing secondary models, taking into account the effects of temperature, water phase salt content, phenolic content, and additional factors (e.g. pH, lactate, dissolved CO2). The secondary model proposed by Devlieghere et al. [Devlieghere, F., Geeraerd, A.H., Versyck, K.J., Vandewaetere, B., van Impe, J., Debevere, J., 2001. Growth of Listeria monocytogenes in modified atmosphere packed cooked meat products: a predictive model. Food Microbiology 18, 53-66.] and modified by Giménez and Dalgaard [Giménez, B., Dalgaard, P., 2004. Modelling and predicting the simultaneous growth of Listeria monocytogenes and spoilage micro-organisms in cold-smoked salmon. Journal of Applied Microbiology 96, 96-109.] appears appropriate. However, further research is needed to understand all effects affecting growth of L. monocytogenes in cold-smoked salmon and to obtain fully validated predictive models for use in quantitative risk assessment.
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Manipulación de Alimentos/métodos , Conservación de Alimentos/métodos , Listeria monocytogenes/crecimiento & desarrollo , Salmón/microbiología , Alimentos Marinos/microbiología , Animales , Seguridad de Productos para el Consumidor , Embalaje de Alimentos/métodos , Humanos , Concentración de Iones de Hidrógeno , Oxígeno/metabolismo , Fenoles/farmacología , Valor Predictivo de las Pruebas , Medición de Riesgo , Cloruro de Sodio/farmacología , TemperaturaRESUMEN
An important step in building a computational model is its documentation; a comprehensive and structured documentation can improve the model applicability and transparency in science/research and for regulatory purposes. This is particularly crucial and challenging for environmental and/or human exposure models that aim to establish quantitative relationships between personal exposure levels and their determinants. Exposure models simulate the transport and fate of a contaminant from the source to the receptor and may involve a large set of entities (e.g. all the media the contaminants may pass though). Such complex models are difficult to be described in a comprehensive, unambiguous and accessible way. Bad communication of assumptions, theory, structure and/or parameterization can lead to lack of confidence by the user and it may be source of errors. The goal of this paper is to propose a standard documentation protocol (SDP) for exposure models, i.e. a generic format and a standard structure by which all exposure models could be documented. For this purpose, a CEN (European Committee for Standardisation) workshop was set up with objective to agree on minimum requirements for the amount and type of information to be provided on exposure models documentation along with guidelines for the structure and presentation of the information. The resulting CEN workshop agreement (CWA) was expected to facilitate a more rigorous formulation of exposure models description and the understanding by users. This paper intends to describe the process followed for defining the SDP, the standardisation approach, as well as the main components of the SDP resulting from a wide consultation of interested stakeholders. The main outcome is a CEN CWA which establishes terms and definitions for exposure models and their elements, specifies minimum requirements for the amount and type of information to be documented, and proposes a structure for communicating the documentation to different users.
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Documentación/normas , Exposición a Riesgos Ambientales , Monitoreo del Ambiente/métodos , Medición de Riesgo/métodos , Humanos , Modelos TeóricosRESUMEN
The aim of this work is to study and model the effect of a temperature shift on h(0), the product of the growth rate by the lag phase duration (mulambda). Our work is based on the data of Whiting and Bagi [Int. J. Food Microbiol. 73 (2002) 291], who studied the influence of both the pre-incubation temperature (T(prior)) and the growth temperature (T(growth)) on lambda values of Listeria monocytogenes. We introduce a new model to describe the evolution of the parameter h(0) as a function of T(prior) and T(growth), and compare it to Whiting and Bagi's published polynomial model that describes the influence of T(prior) and T(growth) on lambda independently of mu. For exponential as well as stationary phase cells, h(0) increases almost linearly with the magnitude of the temperature shift. A simple linear model of h(0) turns out to be more suitable to predict lambda values than a polynomial model of lambda.
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Microbiología de Alimentos , Listeria monocytogenes/crecimiento & desarrollo , Modelos Biológicos , Temperatura , Cinética , Modelos Lineales , Modelos EstadísticosRESUMEN
In this research, we question the straight-forward use of the classical sum of squared error criterion for identifying the typical parameters of a primary model (like growth rate mumax and lag time lambda) when applied to growth curves obtained in and on food products. Firstly, we base our reflections on 62 Listeria monocytogenes laboratory challenge tests collected in various environments (broth, crushed cold-smoked salmon, and surface of cold-smoked salmon slices). Whereas growth data in broth resulted in residual values consistent with a Gaussian distribution, growth data in the crushed product and even more on the surface of slices appeared different. Secondly, we propose the use of an alternative so-called robust non-linear regression method suitable when experimental error is non-normally distributed, which seems, according to this research, typical for microbial challenge tests in/on food products, and which lead to apparent outliers or leverage points in the experimental data. Properties of the robust regression procedure are illustrated on simulated data first, whereafter its use on the considered challenge tests is illustrated. To conclude, reflections on the assumptions and related realism underlying challenge tests and recommendations for fitting growth curves obtained in and on food products are presented.
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Listeria monocytogenes/crecimiento & desarrollo , Modelos Biológicos , Modelos Estadísticos , Salmón/microbiología , Alimentos Marinos/microbiología , Animales , Seguridad de Productos para el Consumidor , Microbiología de Alimentos , CinéticaRESUMEN
SYMBIOSE is a modelling platform that accounts for variability and uncertainty in radiological impact assessments, when simulating the environmental fate of radionuclides and assessing doses to human populations. The default database of SYMBIOSE is partly based on parameter values that are summarized within International Atomic Energy Agency (IAEA) documents. To characterize uncertainty on the transfer parameters, 331 Probability Distribution Functions (PDFs) were defined from the summary statistics provided within the IAEA documents (i.e. sample size, minimal and maximum values, arithmetic and geometric means, standard and geometric standard deviations) and are made available as spreadsheet files. The methods used to derive the PDFs without complete data sets, but merely the summary statistics, are presented. Then, a simple case-study illustrates the use of the database in a second-order Monte Carlo calculation, separating parametric uncertainty and inter-individual variability.
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Radioisótopos/análisis , IncertidumbreRESUMEN
The toxicity of redox cycling compounds which generate the formation of active oxygen species is commonly accepted to be associated with a decrease of cellular reductants involved in cellular defence. However, when hepatocytes were incubated with diquat, an established redox cycler, in the presence of ascorbic acid (AA) (1 mM), the intracellular level of AA was increased. The effects of diquat on AA uptake were investigated in isolated rat hepatocytes. Incubation of hepatocytes with diquat plus AA (1 mM) resulted in about a 2-fold increased accumulation which occurred in a time-dependent manner reaching a steady state after 15 min at 37 degrees. The initial AA uptake rate was dependent on the AA concentration added. This process is described by Michaelis-Menten kinetics (apparent Km = 953 +/- 59 microM and Vmax = 2.68 nmol/min/10(6) cells). Characterization of AA accumulation showed it to be inhibited: by incubation at 4 degrees; with carbonyl cyanide p-trifluoromethoxyphenylhydrazone, an inhibitor of intracellular ATP production; by decreasing the extracellular Na+ concentration or incubating with ouabain; with pfloretin, a glucose transport inhibitor; and with glucose, a competitive inhibitor of AA transport. Replacement of AA with its oxidized form, dehydroascorbic acid, in the absence of diquat enhanced AA accumulation by 2.5-fold and apparently prevented further accumulation by added diquat. In addition, maintaining AA reduced with dithiothreitol inhibited the diquat effect. Diquat-induced AA accumulation was inhibited (65%) by desferrioxamine, a free-iron chelator, but not by catalase and/or superoxide dismutase or different antioxidants. In contrast, incubation with other active oxygen species generating systems including bipyridilium structural analogues, paraquat and benzyl viologen, had no effect on AA accumulation in hepatocytes. These results suggest that diquat-induced AA accumulation by hepatocytes occurs by a specific mediated transport system rather than as a consequence of cytotoxicity and may involve the presence of free-iron.
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Ácido Ascórbico/metabolismo , Diquat/farmacología , Hígado/metabolismo , Animales , Transporte Biológico , Células Cultivadas , Ácido Deshidroascórbico/metabolismo , Ditiotreitol/farmacología , Hígado/efectos de los fármacos , Masculino , Ouabaína/farmacología , Oxidación-Reducción , Ratas , Ratas Wistar , Especies Reactivas de Oxígeno , Sodio/farmacología , Regulación hacia Arriba/efectos de los fármacos , Valinomicina/farmacologíaRESUMEN
Identification of the proximate peroxisome proliferator(s) derived from di (2-ethylhexyl) adipate (DEHA) has been achieved using primary hepatocyte cultures derived from different species and cyanide-insensitive fatty acyl CoA oxidase (PCO) as a marker enzyme for peroxisome proliferation. In rat and mouse hepatocytes, the parent compound (DEHA) had no effect on peroxisomal beta-oxidation, but primary metabolites of DEHA, mono (2-ethylhexyl) adipate (MEHA) and 2-ethylhexanol (EH), were approximately equipotent in PCO induction (5-fold at 0.5 mM final concentration). The secondary metabolite of DEHA, 2-ethylhexanoic acid (EHA), was in both species the most potent peroxisome proliferator (25- and 9-fold induction in mice and rats, respectively, at 1 mM final concentration). At 2 mM final concentration a tertiary metabolite of DEHA, 2-ethyl-5-hydroxyhexan-1-oic acid, was less effective in mouse and rat hepatocytes at inducing PCO (15- and 5-fold, respectively). 2-Ethyl-5-oxohexan-1-oic acid and 2-ethylhexan-1,6-dioic acid had little effect (2-3-fold in both rat and mouse hepatocytes). Thus, EHA was identified as the proximate peroxisome proliferator of DEHA and mouse hepatocytes were approximately twice as sensitive as rat hepatocytes to peroxisome proliferation due to MEHA, EH and EHA. We investigated further species differences in response to peroxisome proliferators by using guinea pig and marmoset primary hepatocyte culture. None of the chemicals studied stimulated peroxisomal beta-oxidation in these species up to a final concentration of 2 mM. Higher concentrations lead to cytotoxicity. This lack of sensitivity of guinea pig and marmoset hepatocytes is in agreement with previous studies with di (2-ethylhexyl) phthalate metabolites, suggesting the absence of a threat of hepatocarcinogenic damage to these species and confirming that primary hepatocytes cultures are useful models for investigating the phenomenon of peroxisome proliferation.
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Adipatos/farmacología , Hígado/efectos de los fármacos , Microcuerpos/efectos de los fármacos , Plastificantes/farmacología , Adipatos/metabolismo , Animales , Callithrix , Células Cultivadas , Cobayas , Hígado/ultraestructura , Masculino , Ratones , Modelos Químicos , Oxidación-Reducción , Ácidos Ftálicos/metabolismo , Ratas , Especificidad de la EspecieRESUMEN
In terms of parasitaemia in blood, the prevalence was 18.7% for Plasmodium falciparum, 10.5% for P. ovale and 1% for P. malariae in the villages of Mungo Ndor and Kokobuma. The plasmodial index of children from 2 to 9 years of age was 38.2% and the spleen index 26.6%, with a mean HACKETT score of 1.56. Malaria is thus meso-endemic in the region. The immunofluorescent test performed with a P. falciparum antigen was positive in 66% of the children in the same age group. Parasites were seen in 15% of new-born children. The malaria infection indices were higher in Mungo Ndor, which is located on the main road in the vicinity of the Manyemen hospital, than in Kokobuma. Morbidity and mortality due to malaria remain major problems in this part of the South-West Province, in spite of improving primary health care facilities and free chloroquine distribution. Anopheles gambiae is the main vector of malaria in the area, and transmission is interrupted only during the short dry season.
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Malaria/epidemiología , Adolescente , Adulto , Factores de Edad , Anciano , Animales , Antígenos de Protozoos/análisis , Camerún , Niño , Preescolar , Femenino , Humanos , Lactante , Malaria/parasitología , Masculino , Persona de Mediana Edad , Plasmodium/aislamiento & purificación , Plasmodium falciparum/inmunología , Plasmodium falciparum/aislamiento & purificación , Plasmodium malariae/aislamiento & purificación , Bazo/parasitologíaRESUMEN
This paper describes a dynamic compartment model (TOCATTA) that simulates tritium transfer in agricultural plants of several categories including vegetables, pasture and annual crops, exposed to time-varying HTO concentrations of water vapour in the air and possibly in irrigation and rainwater. Consideration is also given to the transfer pathways of HTO in soil. Though the transfer of tritium is quite complex, from its release into the environment to its absorption and its incorporation within the organic material of living organisms, the TOCATTA model is relatively simple, with a limited number of compartments and input parameters appropriate to its use in an operational mode. In this paper, we took the opportunity to have data obtained on an ornamental plant - an indoor palm tree - within an industrial building where tritium was released accidentally over several weeks (or months). More specifically, the model's ability to provide hindsight on the chronology of the release scenario is discussed by comparing model predictions of TFWT and OBT activity concentrations in the plant leaves with measurements performed on three different leaves characterized by different developmental stages. The data-model comparison shows some limitations, mainly because of a lack of knowledge about the initial conditions of the accident and when it actually started and about the processes involved in the transfer of tritium. Efforts are needed in both experimental and modelling areas for future evaluation of tritium behaviour in agricultural soil and plants exposed to gaseous HTO releases and/or to irrigation with contaminated water.
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Contaminantes Radiactivos del Aire/metabolismo , Modelos Teóricos , Plantas/metabolismo , Contaminantes Radiactivos del Suelo/metabolismo , Tritio/metabolismo , Hojas de la Planta/metabolismoRESUMEN
With intentions of integrating a portion of their respective research efforts into a trans-national programme that will enhance radioecology, eight European organisations recently formed the European Radioecology ALLIANCE (www.er-alliance.org). The ALLIANCE is an Association open to other organisations throughout the world with similar interests in promoting radioecology. The ALLIANCE members recognised that their shared radioecological research could be enhanced by efficiently pooling resources among its partner organizations and prioritising group efforts along common themes of mutual interest. A major step in this prioritisation process was to develop a Strategic Research Agenda (SRA). An EC-funded Network of Excellence in Radioecology, called STAR (Strategy for Allied Radioecology), was formed, in part, to develop the SRA. This document is the first published draft of the SRA. The SRA outlines a suggested prioritisation of research topics in radioecology, with the goal of improving research efficiency and more rapidly advancing the science. It responds to the question: "What topics, if critically addressed over the next 20 years, would significantly advance radioecology?" The three Scientific Challenges presented within the SRA, with their 15 associated research lines, are a strategic vision of what radioecology can achieve in the future. Meeting these challenges will require a directed effort and collaboration with many organisations the world over. Addressing these challenges is important to the advancement of radioecology and in providing scientific knowledge to decision makers. Although the development of the draft SRA has largely been a European effort, the hope is that it will initiate an open dialogue within the international radioecology community and its stakeholders. This is an abbreviated document with the intention of introducing the SRA and inviting contributions from interested stakeholders. Critique and input for improving the SRA are welcomed via a link on the STAR website (www.star-radioecology.org).
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Ecología , Radiactividad , Investigación , Ambiente , Contaminantes Radiactivos , Sociedades CientíficasRESUMEN
OBJECTIVES: To compare evolution and characteristics of in utero transfers (IUT) in Basse-Normandie area, France, between 2004 and 2008, and to describe characteristics of IUT in 2008. MATERIALS AND METHODS: Analysis of data from the IUT registry, collected prospectively since 2004. RESULTS: An average of five IUT per week was observed. The rate of IUT regularly increased (P=0.003) and reached 16.2 per 1000 pregnancies in 2008. Extra network IUT decreased steadily (P=0.04). For level 3 units, the proportion of IUT from level 2 units increased (P<10(-3)). Before 32 weeks of gestational age, all IUT were done towards a level 3 unit. Median time between IUT and delivery and caesarean section rates were variable according to IUT indication (for threats of premature delivery, respectively 5 days and 23.3%). The rate of retransfer towards initial unit of towards a birth site of relevant level was 5.3%. CONCLUSION: The IUT registry gives useful information on evolution and characteristics of IUT in our area. An increased regionalisation and more frequent adequate IUT were observed. The registry must now serve as a basis for practices assessment.