976 resultados para exposure period


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Sera from 9,254 individuals that presented at one of three outpatient clinics in Quito, Ecuador were assayed by indirect hemagglutination for the presence of antibodies reactive with antigens from Taenia solium cysts. Immunoblot anlysis of 81 selected sera with IHA titers ranging from 0 to 1,028 showed that a titer of maior ou igual a 32 was suggestive of exposure to the parasite. Nine percent (9 %) of the 9,254 patients had titers of 32 or greater. Of 3,503 sera from one clinic, which included sera from food handlers undergoing yearly physicals, 390 (11 %) were positive. In addition, a correlation with age was seen in some, but not all, populations. In situations where age-related effects were noted, the highest incidence was seen in the youngest (0-20 years) and in the oldest (51-60 years) group. Thus, a resurgence of infection after a period of lower prevalence may be developing. Overall, this study shows that cysticercosis is relatively common and potentially a serious health problem in this region.

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Trends in prevalence rates of onchocercal ocular lesions were examined over the period 1980 to 1990 using data from two cross-sectional surveys. There was evidence for increasing prevalence of anterior chamber microfilariae, iridocyclitis, optic atrophy, and chorioretinopathy. Large increases in prevalence, in particular, were seen for posterior segment lesions: optic atrophy increased from 2.7% to 6.4% and chorioretinopathy from 8.8% to 35.6%. Greatest increases in these lesions were seen in the Chachi which was attributed to the large increases in prevalence of microfilariae in the anterior chamber particularly in those aged 30 years or greater. The study findings suggest that ocular onchocerciasis is evolving in parallel with the well documented parasitological changes.

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Over the last decade, mortality from oral and pharyngeal cancer has been declining in most European countries, but it had been increasing substantially in Hungary, Slovakia and a few other countries of central Europe, reaching rates comparable to those of lung cancer in several western European countries in males. To update trends in oral cancer mortality and further analyse the recent epidemic in central Europe, official death certifications for oral and pharyngeal cancer for 37 European countries were derived over the period 1970-2007, and an age-period-cohort model was fitted for selected countries. Male oral cancer mortality continued to decline in most European countries, including the Russian Federation, and, more importantly, it also started to decline in some of the countries with the highest male rates, i.e. Hungary and Slovakia; persisting rises were, however, observed in Belarus, Bulgaria and Romania. Oral cancer mortality rates for women were lower than in men and showed no appreciable trend over recent periods in the EU overall. Estimates from the age-period-cohort analysis for most selected countries showed a fall in effects for the cohorts born after the 1950s. For the period effect displayed a rise for the earlier periods, an inversion in the 1990s and a continuous fall up to the last studied period. Only some former non-market economy countries, like Romania, Ukraine and Lithuania, had rising cohort effect trends up to most recent generations. The major finding of this updated analysis of oral cancer mortality is the leveling of the epidemic for men in most European countries, including Hungary and other central European countries, where mortality from this cancer was exceedingly high. These trends essentially reflect the changes in alcohol and tobacco consumption in various populations.

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Background: It is suggested that a low dose of valganciclovir can be equally effective than a standard dose for cytomegalovirus (CMV) prophylaxis after kidney transplantation. The aim of our study was to determine the ganciclovir exposure observed under a routine daily dosage of 450 mg valganciclovir in kidney transplant recipients with a wide range of renal function. Methods: In this prospective study, kidney transplant recipients with a GFR MDRD above 25 mL/min at risk for CMV (donor or recipient seropositive for CMV) received a dose of valganciclovir (450 mg daily) prophylaxis for 3 months. Ganciclovir levels at trough (Ctrough) and at peak (C3h) were measured monthly. Ganciclovir exposure (AUC0-24) was estimated using Bayesian non-linear mixed-effect modelling (NONMEM) and compared between 3 groups of patients according to their kidney function: GFRMDRD 26-39 mL/min (Group 1), GFRMDRD 40-59 mL/min (Group 2) and GFRMDRD 60-90 mL/min (Group 3). CMV DNAemia was assessed during and after prophylaxis using PCR. Results: Thirty-six patients received 450 mg daily of valganciclovir for 3 months. Median ganciclovir C3h was 3.9 mg/L (range: 1.3-7.1) and Ctrough was 0.4 mg/L (range 0.1-2.7). Median (range) AUC0-24 of ganciclovir was 59.3 mg.h/L (39.0-85.3) in Group 1 patients, 35.8 mg.h/L (24.9-55.8) in Group 2 patients and 29.6 mg.h/L (22.0- 43.2) in Group 3 patients (p<0.001). Anemia was more common in Group 1 patients compared to patients on the other groups (p=0.01). No differences in other adverse events according to ganciclovir exposure were observed. CMV DNAemia was not detected during prophylaxis. After discontinuing prophylaxis, CMV DNAemia was seen in 8/34 patients (23.5%) and 4/36 patients (11%) developed CMV disease. Conclusion: A routine dosage of valganciclovir achieved plasma levels of ganciclovir in patients with GFR>60 mL/min similar to those previously reported using oral ganciclovir. A daily dose of 450 mg valganciclovir appears to be acceptable for CMV prophylaxis in most kidney transplant recipients.

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Empirical modeling of exposure levels has been popular for identifying exposure determinants in occupational hygiene. Traditional data-driven methods used to choose a model on which to base inferences have typically not accounted for the uncertainty linked to the process of selecting the final model. Several new approaches propose making statistical inferences from a set of plausible models rather than from a single model regarded as 'best'. This paper introduces the multimodel averaging approach described in the monograph by Burnham and Anderson. In their approach, a set of plausible models are defined a priori by taking into account the sample size and previous knowledge of variables influent on exposure levels. The Akaike information criterion is then calculated to evaluate the relative support of the data for each model, expressed as Akaike weight, to be interpreted as the probability of the model being the best approximating model given the model set. The model weights can then be used to rank models, quantify the evidence favoring one over another, perform multimodel prediction, estimate the relative influence of the potential predictors and estimate multimodel-averaged effects of determinants. The whole approach is illustrated with the analysis of a data set of 1500 volatile organic compound exposure levels collected by the Institute for work and health (Lausanne, Switzerland) over 20 years, each concentration having been divided by the relevant Swiss occupational exposure limit and log-transformed before analysis. Multimodel inference represents a promising procedure for modeling exposure levels that incorporates the notion that several models can be supported by the data and permits to evaluate to a certain extent model selection uncertainty, which is seldom mentioned in current practice.

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PURPOSE: In Burkina Faso, gold ore is one of the main sources of income for an important part of the active population. Artisan gold miners use mercury in the extraction, a toxic metal whose human health risks are well known. The aim of the present study was to assess mercury exposure as well as to understand the exposure determinants of gold miners in Burkinabe small-scale mines.METHODS: The examined gold miners' population on the different selected gold mining sites was composed by persons who were directly and indirectly related to gold mining activities. But measurement of urinary mercury was performed on workers most susceptible to be exposed to mercury. Thus, occupational exposure to mercury was evaluated among ninety-three workers belonging to eight different gold mining sites spread in six regions of Burkina Faso. Among others, work-related exposure determinants were taken into account for each person during urine sampling as for example amalgamating or heating mercury. All participants were medically examined by a local medical team in order to identify possible symptoms related to the toxic effect of mercury.RESULTS: Mercury levels were high, showing that 69% of the measurements exceeded the ACGIH (American Conference of Industrial Hygienists) biological exposure indice (BEI) of 35 µg per g of creatinine (µg/g-Cr) (prior to shift) while 16% even exceeded 350 µg/g-Cr. Basically, unspecific but also specific symptoms related to mercury toxicity could be underlined among the persons who were directly related to gold mining activities. Only one-third among the studied subpopulation reported about less than three symptoms possibly associated to mercury exposure and nearly half of them suffered from at least five of these symptoms. Ore washers were more involved in the direct handling of mercury while gold dealers in the final gold recovery activities. These differences may explain the overexposure observed in gold dealers and indicate that the refining process is the major source of exposure.CONCLUSIONS: This study attests that mercury exposure still is an issue of concern. North-South collaborations should encourage knowledge exchange between developing and developed countries, for a cleaner artisanal gold mining process and thus for reducing human health and environmental hazards due to mercury use.

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Abstract Purpose: New treatments against long-lasting uveitis need to be tested. Our aim was to develop a six-week model of uveitis in rabbits. Methods: Rabbits were presensitized with an s.c. injection of Mycobacterium tuberculosis H37RA emulsified with TiterMax® Gold adjuvant. Uveitis was induced at day 28 and 50, by intravitreal challenges of antigen suspension. Ocular inflammation was assessed till euthanasia at day 71 after s.c. injection of M. tuberculosis H37RA by: (a) the number of inflammatory cells in aqueous humor (AH); (b) the protein concentration in AH; (c) the clinical score (mean of conjunctival hyperaemia, conjunctival chemosis, oedema and secretion); (d) the microscopical score (mean presence of fibrin and synechiae, aqueous cell density and aqueous flare grade, as scored by slit lamp). Results: At the sites of presensitization injection, rabbits presented flat nodules which progressively vanished. The first challenge induced a significant increase in the four parameters (p < 0.05 the Wilcoxon/Kruskal-Wallis test). The AH contained 764 ± 82 cells/µl and 32 ± 0.77 mg protein/ml. During the following days, inflammatory parameters decreased slightly. The second intravitreal challenge increased inflammation (3564 ± 228 cells/µl AH and 31 ± 1 mg protein/ml), which remained at a high level for a longer period of time. Conclusion: We developed a model of long-term uveitis, which could be maintained in rabbits for at least six weeks. Such a model could be used to test the efficacy of either new drugs or various drug delivery systems intended to deliver active agents during a few months.

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Combustion-derived and manufactured nanoparticles (NPs) are known to provoke oxidative stress and inflammatory responses in human lung cells; therefore, they play an important role during the development of adverse health effects. As the lungs are composed of more than 40 different cell types, it is of particular interest to perform toxicological studies with co-cultures systems, rather than with monocultures of only one cell type, to gain a better understanding of complex cellular reactions upon exposure to toxic substances. Monocultures of A549 human epithelial lung cells, human monocyte-derived macrophages and monocyte-derived dendritic cells (MDDCs) as well as triple cell co-cultures consisting of all three cell types were exposed to combustion-derived NPs (diesel exhaust particles) and to manufactured NPs (titanium dioxide and single-walled carbon nanotubes). The penetration of particles into cells was analysed by transmission electron microscopy. The amount of intracellular reactive oxygen species (ROS), the total antioxidant capacity (TAC) and the production of tumour necrosis factor (TNF)-a and interleukin (IL)-8 were quantified. The results of the monocultures were summed with an adjustment for the number of each single cell type in the triple cell co-culture. All three particle types were found in all cell and culture types. The production of ROS was induced by all particle types in all cell cultures except in monocultures of MDDCs. The TAC and the (pro-)inflammatory reactions were not statistically significantly increased by particle exposure in any of the cell cultures. Interestingly, in the triple cell co-cultures, the TAC and IL-8 concentrations were lower and the TNF-a concentrations were higher than the expected values calculated from the monocultures. The interplay of different lung cell types seems to substantially modulate the oxidative stress and the inflammatory responses after NP exposure. [Authors]

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The survival, physiology and gene expression profile of the phenanthrene-degrading Sphingomonas sp. LH128 was examined after an extended period of complete nutrient starvation and compared with a non-starved population that had been harvested in exponential phase. After 6 months of starvation in an isotonic solution, only 5 % of the initial population formed culturable cells. Microscopic observation of GFP fluorescent cells, however, suggested that a larger fraction of cells (up to 80 %) were still alive and apparently had entered a viable but non-culturable (VBNC) state. The strain displayed several cellular and genetic adaptive strategies to survive long-term starvation. Flow cytometry, microscopic observation and fatty acid methyl ester (FAME) analysis showed a reduction in cell size, a change in cell shape and an increase in the degree of membrane fatty acid saturation. Transcriptome analysis showed decreased expression of genes involved in ribosomal protein biosynthesis, chromosomal replication, cell division and aromatic catabolism, increased expression of genes involved in regulation of gene expression and efflux systems, genetic translocations, and degradation of rRNA and fatty acids. Those phenotypic and transcriptomic changes were not observed after 4 h of starvation. Despite the starvation situation, the polycyclic aromatic hydrocarbon (PAH) catabolic activity was immediate upon exposure to phenanthrene. We conclude that a large fraction of cells maintain viability after an extended period of starvation apparently due to tuning the expression of a wide variety of cellular processes. Due to these survival attributes, bacteria of the genus Sphingomonas, like strain LH128, could be considered as suitable targets for use in remediation of nutrient-poor PAH-contaminated environments.

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Background/Purpose: Denosumab (DMAb) is an approved therapy for the treatment of postmenopausal women with osteoporosis at increased risk for fracture. A favorable risk/benefit profile was demonstrated in the pivotal, 3-year FREEDOM trial (Cummings et al NEJM 2009). The open-label, active-treatment FREEDOM Extension study is investigating the efficacy and safety of DMAb for up to 10 years. The Extension trial enrolled women who had received DMAb or placebo in FREEDOM and provides an opportunity to evaluate the long-term efficacy and safety of continuous DMAb treatment (long-term group), and to replicate the DMAb findings observed in FREEDOM (cross-over group). Here, we report the results from the first 3 years of the Extension, representing up to 6 continuous years of DMAb exposure.Methods: During the Extension, each woman is scheduled to receive 60 mg DMAb every 6 months and supplemental calcium and vitamin D daily. For the analyses reported here, women from the FREEDOM DMAb group received 3 more years of DMAb for a total of 6 years of exposure (long-term group) and women from the FREEDOM placebo group received 3 years of DMAb exposure (cross-over group).Results: Of the 5928 women eligible for the Extension, 4550 (77%) enrolled (N_2343 long-term; N_2207 cross-over). In the long-term group, further significant mean increases in bone mineral density (BMD) occurred 4044 for cumulative 6-year gains of 15.2% at the lumbar spine and 7.5% at the total hip (Figure). During the first 3 years of DMAb treatment during the Extension, the cross-over group had significant mean gains in BMD at the lumbar spine (9.4%) and total hip (4.8%), similar to those observed in the long-term DMAb group during the first 3 years of FREEDOM (lumbar spine, 10.1%; total hip, 5.7%). Serum CTX was rapidly and similarly reduced after the 1st (cross-over) or 7th (long-term) DMAb dose with the characteristic attenuation observed at the end of the dosing period. In the cross-over group, yearly incidences of new vertebral and nonvertebral fractures were lower than in the FREEDOM placebo group. Fracture incidence remained low in the long-term group. Incidences of adverse events (AEs) and serious AEs did not increase over time with DMAb treatment. There were 2 subjects with AEs adjudicated to ONJ in the cross-over group and 2 in the long-term group. Both cases in the cross-over group healed completely and without further complications; 1 of these subjects continues to receive DMAb. Both women in the long-term group continue to be followed. No atypical femur fractures have been observed to date. Figure. Percent changes in bone mineral density during FREEDOM and the Extension Conclusion: DMAb treatment for 6 continuous years (long-term group) remained well tolerated, maintained reduced bone turnover, and continued to significantly increase BMD. Fracture incidence remained low. DMAb treatment for 3 years in the cross-over group reproduced the original observations in FREEDOM.

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The history of tax havens during the decades before World War II is still little known. To date, the studies that have focused on the 1920s and 1930s have presented either a very general perspective on the development of tax havens or a narrow national point of view. Based on unpublished historical archives of five countries (Switzerland, Great Britain, Belgium, France, Germany), this paper offers therefore a new comparative appraisal of international tax competition during this period in order to answer the following question: What was the specificity of the Swiss case - already considered a quintessential tax haven at the time - in comparison to other banking centres? The findings of this research study are twofold. First, the 1920s and 1930s appear as something of a golden age of opportunity for avoiding taxation through the relocation of assets. Most of the financial centres granted consistent tax benefits for imported capital, while the limited degree of international cooperation and the usual guarantee of banking secrecy in European countries prevented the taxation of exported assets. Second, within this general environment, the fiscal strategies of a tax haven like Switzerland differed from those of a great financial power like Great Britain. Whereas the Swiss administration readily placed itself at the service of the banking community, British policy was more balanced between the contradictory interests of the Board of Inland Revenue, the Treasury, and the English business circles.

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English translation of the Executive summary of the report “Catalonia’s participation in calls of the EU 7th Framework Programme for RTD. Period 2007-2009” drawn up by researchers of the AQR Research Group – Research Institute of Applied Economics (IREA) of the University of Barcelona. It aims to find out the reality of the Catalonia’s participation in the EU 7th Framework Programme, the main European financial instrument for research during the period 2007-2009.