Biomedical subjects

T Gouin

Publications and source records attributed to T Gouin.

6 recordsLinked to original sources

PubMed2006

Concentrations of decabromodiphenyl ether in air from Southern Ontario: implications for particle-bound transport.

Atmospheric concentrations are reported for the main component of the brominated flame retardant decaBDE (BDE-209) in air samples collected from Southern Ontario for the period January 23-June 06, 2002. Levels ranged from below detection to 105pgm(-3) with virtually all of BDE-209 being trapped by the filter and thus deduced to be sorbed to aerosol particles. Thus, it is likely that the long-range atmospheric transport (LRAT) of BDE-209 is controlled by the transport characteristics of the aerosols. This conclusion that BDE-209 does not have the same potential for LRAT as other more volatile PBDEs is subject to possible complications arising from the uncertainties about the LRAT potential of aerosols.

Air↗

PubMed2005

Passive and active air samplers as complementary methods for investigating persistent organic pollutants in the Great Lakes Basin.

Data obtained using passive air samplers (PAS) are compared to active high-volume air sampling data in order to assess the feasibility of the PAS as a method, complementary to active high-volume air sampling (AAS), for monitoring levels of organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in the Laurentian Great Lakes. PAS were deployed at 15 of the Integrated Atmospheric Deposition Network (IADN) sites on a quarterly basis between July 2002 and June 2003, and PAS and AAS results are compared. Levels for the OC pesticides are typically highest in agricultural areas, with endosulfan I dominating air concentrations with values ranging between 40 and 1090 pg x m(-3), dieldrin values between 15 and 165 pg x m(-3), and gamma-HCH values between 13 and 100 pg x m(-3). alpha-HCH was seen to be relatively uniform across the Great Lakes Basin with values ranging between 15 and 73 pg x m(-3). Large urban centers, such as Chicago and Toronto, have the highest levels of PCBs and PBDEs that range between 400 and 1200 pg x m(-3) and 10 and 70 pg x m(-3), respectively. Comparison of the AAS and the PAS data collected during this study shows good agreement, within a factor of 2 or 3, suggesting that the two sample methods produce comparable results. It is suggested that PAS networks, while providing data that are different in nature from AAS, can provide a cost-effective and complementary approach for monitoring the spatial and temporal trends of persistent organic pollutants.

Air Pollutants↗

PubMed2005

[Isotretinoin: compliance with recommendations in childbearing women].

INTRODUCTION: The aim of this survey is to ascertain if the incidence of isotretinoin exposed pregnancies was reduced by the late recommendations of prescription and issue (AMM modification on 06/08/2001 and 25/09/2001). METHODS: All isotretinoin exposed pregnancies registered by the French Regional Drug Monitoring Centres, the Information Centre for Teratogenic Agents and Roche (Roaccutane), Pierre Fabre (Curacné Gé) and Expanscience (Procuta Gé) laboratories, from January 1st, 1999 to December 31st, 2002, were analysed. Enforcement of the strengthening of isotretinoin prescription recommendations was analysed on a sample of 68 prescriptions from 45 pharmacies throughout France. RESULTS: In 4 years, 103 isotretinoin exposed pregnancies (Roaccutane 97 p. 100, Curacné(R) Gé 3 p. 100) during teratogenic risk period, were registered. Pregnancy started less than one month after isotretinoin stopping (37 p. 100), during the treatment (43 p. 100), or was in progress when the treatment was initiated (20 p. 100). The reason of the 22 lacking contraception was known 12 times, i.e. an absence of prescription (6 times), a refusal to take a prescribed contraception (3 times) and a self-medication (3 times). Among the 71 pregnancies whose contraceptive status is known, 48 p. 100 could had been avoided if recommendations had been followed (pregnancies due to a premature stopping or an absence of contraception). The issue of pregnancies is a voluntary termination in 60 cases (87 p. 100). Malformations frequency is 25 p. 100. Incidence of isotretinoin exposed pregnancies remained stable, 0.26/1000 treated women (vs 0.34 after 2001's AMM modifications). Of 68 prescriptions studied, 23 (24 p. 100) carried all the legal warnings, which is close to the previous survey's results. Contraception was in accordance with the recommendations in 78 p. 100 of cases and women learned and applied information given in 38 p. 100 of cases. At last, only 6 patients (9 p. 100) have both a correctly written prescription, a contraception and a time between the pregnancy test date and prescription and issue dates, in accordance with the licence and have had a correct information and understood it. Regarding the previous survey, pregnancy test before treatment was more often prescribed (96 p. 100 vs 88 p. 100). On the other hand, less women knew the necessity to keep on taking contraception one month after isotretinoin stopping (82 p. 100 vs 93 p. 100). CONCLUSION: Despite 3 successive isotretinoin prescription and issue recommendations strengthening in childbearing women, pregnancies can't be totally avoided. Bad compliance concerns the prescription and/or an incomplete or not understood information by the patient who does not scrupulously apply the care and contraception agreement. However, this study does not allow to assess the proportion of issued prescriptions despite their non-accordance with the licence criteria. The National Commission of Pharmacovigilance did not like to limit isotretinoin prescription to dermatologists only. It estimates that the administrative authority must intensify information by dermatologists, general practitioners and pharmacists, about measures to take to avoid an exposure to isotretinoin during pregnancy.

Abnormalities, Drug-Induced↗

PubMed2004

Evidence for the "grasshopper" effect and fractionation during long-range atmospheric transport of organic contaminants.

Although there is indisputable evidence that long-range atmospheric transport (LRAT) of organic contaminants occurs on a global scale, uncertainties remain about the detailed mechanism and extent of this phenomenon as well as the physical-chemical properties which facilitate LRAT. In this study, we discuss how mass balance models and monitoring data can contribute to a fuller understanding of the mechanism and extent of LRAT. Specifically we address the issues of "grasshopping" or "hopping" (the extent to which molecules are subject to multiple hops as distinct from a single emission-deposition event) and "global fractionation" (the differing behavior of chemicals as they are transported). It is shown that simple mass balance models can be used to assist the interpretation of monitoring data while also providing an instrument that can be used to assess the LRAT potential and the extent of hopping that organic substances may experience. The available evidence supports the notion that many persistent organic pollutants experience varying degrees of "hopping" during their environmental journey and as a consequence become fractionated with distance from source.

Air Movements↗

PubMed2003

Modelling the environmental fate of the polybrominated diphenyl ethers.

In response to growing alarm over the occurrence of polybrominated diphenyl ethers (PBDEs) in remote regions, this study considers their physical chemistry, environmental partitioning and considerations regarding potential for long-range atmospheric transport (LRAT). Internally consistent physical-chemical property data are presented for five representative congeners (PBDE-15, -28, -47, -99, -153) and used in a multimedia modelling approach. Results of the Level II model indicate that PBDEs will largely partition to organic carbon in soil and sediment and that their persistence will be strongly influenced by degradation rates in these media that are not well known. TaPL3 model estimates of their characteristic travel distance (CTD) suggest limited LRAT potential. The LRAT is also evaluated qualitatively, in terms of surface-air exchange behaviour. PBDEs are shown to be sensitive to seasonally and diurnally fluctuating temperatures. When vegetation is included in the model, 50% of the total mass of PBDE-47 deposited to vegetation returns to the atmosphere, suggesting that it may migrate through a series of deposition/volatilisation hops. Key data that needs to be identified in this evaluation include a better understanding of air-surface exchange, particularly to foliage, and measurements of degradation rates in soil, sediment and vegetation.

Atmosphere↗

PubMed2002

Air-surface exchange of polybrominated diphenyl ethers and polychlorinated biphenyls.

Air and leaf-litter samples were collected from a rural site in southern Ontario under meteorologically stable conditions in the early spring, prior to bud burst, over a three-day period to measure the simultaneous diurnal variations in polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). PBDEs are used in a wide range of commercial products as flame retardants and are being assessed internationally as potential persistent organic pollutants. Total PBDE concentrations in the air ranged between 88 and 1250 pg m(-3), and were dominated primarily by the lighter congeners PBDEs 17, 28, and 47, and concentrations of total PCBs ranged between 96 and 950 pg m(-3), and were dominated by the lower chlorinated (tri- to tetra-) congeners. Slopes of Clausius-Clapeyron plots indicate that both PCBs and PBDEs are experiencing active air-surface exchange. Fugacities were estimated from concentrations in the air and leaf-litter and suggest near equilibrium conditions. Following the three-day intensive sampling period, 40 air samples were collected at 24-hour intervals in an attempt to evaluate the effect of bud burst on atmospheric concentrations. Total PBDE concentrations in the daily air samples ranged between 10 and 230 pg m(-3), and were dominated by the lighter congeners PBDE 17, 28, and 47, whereas concentrations of total PCBs ranged between 30 and 450 pg m(-3) during this period. It is hypothesized thatthe high PBDE concentrations observed at the beginning of the sampling period are the result of an "early spring pulse" in which PBDEs deposited in the snowpack over the winter are released with snowmelt, resulting in elevated concentrations in the surface and air. Later in the sampling period, following bud burst, PBDE concentrations in air fell to 10 to 20 pg m(-3), possibly due to the high sorption capacity of this freshly emerging foliage compartment.

Adsorption↗