Corinne Charlier

Simultaneous determination of some phthalate metabolites, parabens and benzophenone-3 in urine by ultra high pressure liquid chromatography tandem mass spectrometry

Phthalates, parabens and 2-hydroxy-4-methoxybenzophenone or benzophone-3 are thought to act as endocrine disrupting chemicals, being able to disrupt the endocrine balance and therefore able to lead to some hormonal diseases. Numerous large-scale biomonitoring studies have detected the biomarkers of these compounds in more than 75% of the general population. To assess the exposure to these chemicals, we developed an analytical method based on a Solid Phase Extraction (SPE) prior to ultra high pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the simultaneous measurement of seven phthalate metabolites (monobenzyl phthalate, mono-n-butyl phthalate, mono-iso-butyl phthalate, mono-2-ethylhexyl phthalate, mono-2-ethyl-5-hydroxyhexyl phthalate, mono-2-ethyl-5-oxohexyl phthalate, monoethyl phthalate), four parabens (methyl paraben, ethyl paraben, n-propyl paraben, n-butyl parabens) and benzophenone-3 in human urine. The distinction between unconjugated, glucuro- and sulfoconjugated forms was achieved using different enzymatic hydrolyses. The whole procedure was validated according to the total error approach, and was demonstrated to be linear (regression coefficient ranging from 0.987 to 0.998) and accurate (inter and intra assay precision <17.71%, relative bias <5.87%) in the dosing range of concentrations. The limits of quantification (LOQs) obtained ranged between 0.30 and 1.23ng/ml depending on the analyte. The reliability of the method was proven in passing successfully the German External Quality Assessment Scheme (G-EQUAS). Moreover, the urine from 25 volunteers were analyzed for the determination of glucuro-, sulfo- and free species separately. Phthalate metabolites, parabens and benzophenone-3 were positively detected in almost all urine samples, with detection rates ranging from 40 to 100%. Levels measured ranged from <LOQ to 2207ng/ml varying widely depending on the compound and the individual. In our small participating population, most of the phthalate metabolites were excreted predominately as glucuroconjugated forms while parabens and benzophenone-3 were detected as glucuro- and sulfoconjugated species in variable proportions according to the target compound.

Estimated daily intake and cumulative risk assessment of phthalate diesters in a Belgian general population.

The daily intakes (DI) were estimated in a Belgian general population for 5 phthalates, namely diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), di-iso-butyl phthalate (DiBP), butylbenzyl phthalate (BBzP) and di-2-ethylhexyl phthalate (DEHP), based on the urinary measurements of their corresponding metabolites. DI values ranged between <LOD and 59.65 μg/kg bw/day depending on the congener, and were globally higher for children than adults. They were compared to acceptable levels of exposure (tolerable daily intakes) to evaluate the hazard quotients (HQ), which highlight an intake above the dose considered as safe for values greater than 1. If very few of our Belgian participants exceeded this threshold for phthalates considered individually, 6.2% of the adults and 25% of the children showed an excessive hazard index (HI) which took into account the cumulative risk of adverse anti-androgenic effects. These results are of concern since these HI were based on only 3 phthalates (DEHP, DiBP and DnBP), and showed a median of 0.55 and 0.29 for children and adults respectively. The comparison with previously determined dietary intakes demonstrated that for DEHP, food intake was nearly the only route of exposure while other pathways occurred mainly for the other studied phthalates.

Hair mercury and urinary cadmium levels in Belgian children and their mothers within the framework of the COPHES/DEMOCOPHES projects

A harmonized human biomonitoring pilot study was set up within the frame of the European projects DEMOCOPHES and COPHES. In 17 European countries, biomarkers of some environmental pollutants, including urinary cadmium and hair mercury, were measured in children and their mothers in order to obtain European-wide comparison values on these chemicals. The Belgian participant population consisted in 129 school children (6-11 years) and their mothers (≤ 45 years) living in urban or rural areas of Belgium. The geometric mean levels for mercury in hair were 0.383 μg/g and 0.204 μg/g for respectively mothers and children. Cadmium in mothers and childrens urine was detected at a geometric mean concentration of respectively 0.21 and 0.04 μg/l. For both biomarkers, levels measured in the mothers and their child were correlated. While the urinary cadmium levels increased with age, no trend was found for hair mercury content, except the fact that mothers hold higher levels than children. The hair mercury content increased significantly with the number of dental amalgam fillings, explaining partially the higher levels in the mothers by their higher presence rate of these amalgams compared to children. Fish or seafood consumption was the other main parameter determining the mercury levels in hair. No relationship was found between smoking status and cadmium or mercury levels, but the studied population included very few smokers. Urinary cadmium levels were higher in both mothers and children living in urban areas, while for mercury this difference was only significant for children. Our small population showed urinary cadmium and hair mercury levels lower than the health based guidelines suggested by the WHO or the JECFA (Joint FAO/WHO Expert Committee on Food Additives). Only 1% had cadmium level slightly higher than the German HBM-I value (1 μg/l for adults), and 9% exceeded the 1 μg mercury/g hair suggested by the US EPA.

Measurement of urinary biomarkers of parabens, benzophenone-3, and phthalates in a Belgian population.

Parabens, benzophenone-3 (BP3), and phthalates are commonly used as antimicrobial conservator, UV-filter, and plasticizer, respectively, and are thought to exhibit endocrine disrupting properties. These endocrine disrupting activities have been recently assumed to lead to cutaneous malignant melanoma. Humans are exposed to these chemicals through different sources such as food, personal care products, or cosmetics. In this study, we measured urinary levels of 4 parabens, BP3, and 7 metabolites of phthalates in samples collected from 261 participants living in and around Liege (Belgium). The analyses were carried out by liquid chromatography tandem mass spectrometry (LC-MS/MS) using isotopic dilution. To the best of our knowledge, this is the first time that the urinary levels of these 3 classes of chemicals are reported for the same general population in Belgium. Most of the parabens, the BP3, and all the phthalate metabolites were detected in 82.8 to 100.0% of the samples. For most of these chemicals, the exposure patterns significantly differ not only between children and adults, but also between males and females, especially with higher concentrations of parabens and phthalate metabolites in female and children subjects, respectively.

Modelled target attainment after meropenem infusion in patients with severe nosocomial pneumonia: the PROMESSE study

OBJECTIVESnThe objective of this study was to propose an optimal treatment regimen of meropenem in critically ill patients with severe nosocomial pneumonia.nnnPATIENTS AND METHODSnAmong 55 patients in intensive care treated with 1 g of meropenem every 8 h for severe nosocomial pneumonia, 30 were assigned to intermittent infusion (II; over 0.5 h) and 25 to extended infusion (EI; over 3 h) groups. Based on plasma and epithelial lining fluid (ELF) concentrations determined at steady-state, pharmacokinetic modelling and Monte Carlo simulations were undertaken to assess the probability of attaining drug concentrations above the MIC for 40%-100% of the time between doses (%T > 1-fold and 4-fold MIC), for 1 or 2 g administered by either method.nnnRESULTSnPenetration ratio, measured by the ELF/plasma ratio of AUCs, was statistically higher in the EI group than in the II group (mean ± SEM: 0.29 ± 0.030 versus 0.20 ± 0.033, P = 0.047). Considering a maximum susceptibility breakpoint of 2 mg/L, all dosages and modes of infusions achieved 40%-100% T > 1-fold MIC in plasma, but none did so in ELF, and only the 2 g dose over EI achieved 40%-100% T > 4-fold MIC in plasma.nnnCONCLUSIONSnThe optimum regimen to treat severe nosocomial pneumonia was 2 g of meropenem infused over 3 h every 8 h. This regimen achieved the highest pharmacodynamic targets both in plasma and in ELF.

Alteration of Rat Fetal Cerebral Cortex Development after Prenatal Exposure to Polychlorinated Biphenyls

Polychlorinated biphenyls (PCBs) are environmental contaminants that persist in environment and human tissues. Perinatal exposure to these endocrine disruptors causes cognitive deficits and learning disabilities in children. These effects may involve their ability to interfere with thyroid hormone (TH) action. We tested the hypothesis that developmental exposure to PCBs can concomitantly alter TH levels and TH-regulated events during cerebral cortex development: progenitor proliferation, cell cycle exit and neuron migration. Pregnant rats exposed to the commercial PCB mixture Aroclor 1254 ended gestation with reduced total and free serum thyroxine levels. Exposure to Aroclor 1254 increased cell cycle exit of the neuronal progenitors and delayed radial neuronal migration in the fetal cortex. Progenitor cell proliferation, cell death and differentiation rate were not altered by prenatal exposure to PCBs. Given that PCBs remain ubiquitous, though diminishing, contaminants in human systems, it is important that we further understand their deleterious effects in the brain.

Site-, Technique-, and Time-Related Aspects of the Postmortem Redistribution of Diazepam, Methadone, Morphine, and their Metabolites: Interest of Popliteal Vein Blood Sampling

Sampling site, technique, and time influence postmortem drug concentrations. In 57 cases, we studied drug concentration differences as follows: subclavian vein‐dissection/clamping versus blind stick, femoral vein‐dissection/clamping versus blind stick, right cardiac chamber, and popliteal vein‐dissection and clamping only. Cases were distributed in group #1 (all cases with both techniques), group #2 (dissection/clamping), and group #3 (blind stick). Sampled drugs were diazepam, methadone, morphine, and their metabolites. To assess PMR, mean concentrations and ratios were calculated for each group. Time‐dependent variations of blood concentrations and ratios were also assessed. Results indicate that site, method, and time may influence postmortem distribution interpretation in different ways. Popliteal blood seems less subject to PMR. In conclusion, our study is the first to evaluate concurrently three main aspects of PMR and confirms that the popliteal vein may represent a site that is more resistant to the changes seen as a result of PMR.

Postmortem Concentration and Redistribution of Diazepam, Methadone, and Morphine with Subclavian and Femoral Vein Dissection/Clamping.

Postmortem redistribution (PMR) concerns blood drug concentration variations after death, depending on many factors such as sampling site and technique. In our study, we focused on sampling method. 30 cases were sampled, each at cardiac, subclavian, femoral, and popliteal sites. Targeted substances were diazepam, methadone, and morphine. Blind stick and dissection/clamping techniques were concomitantly performed at subclavian and femoral sites. Subclavian and femoral concentrations were compared according to technique used. To assess the influence of sampling technique on PMR, central/peripheral ratios were calculated depending on sampling method. Results show that drug concentrations tend to be lower when drawn from a clamped subclavian or femoral vein whereas ratios including subclavian and/or femoral blood concentration are influenced according to the technique used. In conclusion, clamping a subclavian or femoral vessel before sampling tends to result in lower drug concentrations and may influence ratios, suggesting the importance of isolating vessels from thoraco‐abdominal viscera.

In vivo skin fluorescence imaging in young Caucasian adults with early malignant melanomas

Background Human cutaneous malignant melanoma (CMM) is an aggressive cancer showing a dramatic worldwide increase in incidence over the past few decades. The most prominent relative epidemiological increase has been disclosed in young women. The aim of the study was to assess the effects of chronic sun exposures in order to rate the extend of melanocytic stimulations in the vicinity of CMM. Methods The study was designed to evaluate the melanin distribution and density using ultraviolet light illumination. The present study was performed on surgical excision specimens of thin CMM lesion removed from the upper limbs of 55 Caucasian adults (37 women and 18 men). Two control groups comprised 23 men and 21 women of similar ages who had medium-size congenital melanocytic nevi, also present on the upper limbs. The peritumoral skin was scrutinized using a Visioscan® VC98 device, revealing the faint mosaic melanoderma (FMM) pattern that grossly indicates early signs of chronic photodamage in epidermal melanin units. Results The median extent of relative FMM was significantly higher in the CMM male group. By contrast, the CMM female group showed a reverse bimodal distribution in FMM size. Only 12/37 (32.5%) of the CMM female group had an increased FMM size, whereas 25/37 (67.5%) of females with CMM had a global FMM extent in the normal range, relative to the controls. Conclusion Thin CMM supervening in young women appear unrelated to repeat photoexposure. Other mechanisms are possibly involved.

The current environmental levels of endocrine disruptors (mercury, cadmium, organochlorine pesticides and PCBs) in a Belgian adult population and their predictors of exposure

A human biomonitoring study was carried out measuring the levels of endocrine disruptors in 252 participants (18-76 years old) recruited between February and May 2015 from the general population of Liege Province (Belgium). In this study, we reported the recent levels of cadmium and mercury in urine, some organochlorine pesticides and polychlorinated biphenyls (PCBs) in serum, and their relations to demographic characteristics, lifestyle behaviors and dietary habits. The median urinary levels of mercury and cadmium were 0.81μg/l and <0.5μg/l respectively. The mercury levels were higher in participants having at least 3 dental amalgams, and consuming sea fish more than once a week. Although our mercury levels in most participants were lower than some health-based guidelines, they were higher than in our neighboring countries where ban or restrictions on the dental amalgams use were implemented. Urinary cadmium levels in current smokers were significantly higher than former or never smokers, as well as non-smokers for passively exposed vs non-exposed ones. Median PCB-153 and -180 serum levels were 53.8 and 41.1ng/g lipid respectively, but PCB-138 was below the limit of quantification of 0.15μg/l in 49% of the samples. Among the organochlorine pesticides, 4,4-dichlorodiphenyldichloroethylene (4,4-DDE), beta-hexachlorohexane and hexachlorobenzene were positively detected respectively in 48%, 49% and 37% of the serum samples. Eventhough, a dramatic decrease in organochlorines levels was observed, at least 1 pesticide or PCB was detected in 96% of our population, and more than 50% of our samples were contaminated by 4 or more organochlorines. Age, body mass index, and breastfeeding duration were the most predictive determinants of pesticide or PCB serum concentrations, but not dietary habits.