Biomedical subjects

H Plaisance

Publications and source records attributed to H Plaisance.

4 recordsLinked to original sources

PubMed2005

A case study of personal exposure to nitrogen dioxide using a new high sensitive diffusive sampler.

Personal NO(2) exposure measurements were achieved during two campaigns in a large northern France city. These campaigns were following an innovating approach based on sequential exposure measurements by diffusive samplers distinguishing four categories of microenvironments ("home", "other indoor places", "transport" and "outdoors"). The objective of these campaigns was to obtain NO(2) personal exposure data in different microenvironments and to examine the determinants of personal exposure to this pollutant. Each campaign comprised two 24-h sampling periods: one during a working day and the second during the weekend. The average total NO(2) personal exposure ranged from 17 microg m(-3) for the summer weekend samplings to 38 microg m(-3) for the winter weekday samplings. The highest levels were found in transports and outdoors, the intermediate ones in other indoor places and the lowest in homes. Despite their weak levels, indoor environments contributed for more than 78% to total NO(2) personal exposure because of more time spent in these living places. A Multiple Correspondence Analysis (MCA) highlighted the determinants of NO(2) personal exposure in the "home" and "transport" microenvironments. This led to a classification of NO(2) personal exposure levels according to different means of transport: from the lowest to the highest exposure levels, train, tramway or underground, bicycle, car or motorcycle. In homes, the rise of NO(2) personal exposures is mainly due to the use of gas stoves and gas heating and the absence of automatic airing system. A classification of NO(2) personal exposure levels was set up according to the characteristics of homes. An analysis of correlations between the home NO(2) personal exposures and outdoor concentrations measured by fixed ambient air monitoring stations showed weak relations suggesting that the data of these stations are poor predictors of NO(2) personal exposures in homes.

Air Pollutants↗

PubMed2003

Validation tests of a new high uptake rate passive sampler for nitrogen dioxide measurements.

This study explains the main characteristics of a new passive sampler which is able to give reliable nitrogen dioxide measurements for short time sampling. The sampling rate was found to be on average 0.89 cm3 s(-1) for indoor sampling and 1.00 cm3 s(-1) for outdoor sampling. The detection limit was evaluated at 11 microg m(-3) for a one-hour measurement. In field conditions, the passive sampler measurements were in agreement with those of the chemiluminescent NOx monitors. Measurement uncertainties were estimated at 34% and 38% for laboratory tests in conditions corresponding respectively to indoor and outdoor measurements and were evaluated at 28 to 37% depending on the nitrogen dioxide concentration for field experiments. The effects of various factors on the passive sampler were determined in an exposure chamber. The sampling rate of the retained sampler version was not significantly influenced by wind speeds superior to 0.3 m s(-1). A decrease of the uptake rate is observed for high nitrogen dioxide doses. The sampling rate increases linearly with temperature (2% per degree C). The relative humidity has only a weak effect.

Air Pollutants↗

PubMed2002

Performances and application of a passive sampling method for the simultaneous determination of nitrogen dioxide and sulfur dioxide in ambient air.

The performances and applicability of a diffusion tube sampler for the simultaneous measurements of NO2 and SO2 in ambient air were evaluated. SO2 and NO2 are collected by the passive sampler using triethanolamine as trapping agent and are determined as sulphate and nitrite with ion chromatography. The detection limit (2.3 microg m(-3) of NO2 and 4.2 microg m(-3) of SO2 for two weeks sampling) is adequate for the determination of concentrations in urban and industrial areas. Precision of the method as RSD is in mean 5% for NO2 and 12% for SO2 at the concentration levels in urban areas. Calibration of the method was performed in the field conditions by comparison between the responses of sampler and the concentrations measured by the continuous monitors. High degree of linearity (correlation coefficients > 0.8) is found between the passive sampler tube and the continuous monitor data for both NO2 and SO2. To reduce the wind velocity influence on passive sampling of diffusion tubes, a protective shelter was tested in this study. The overall uncertainty of one measure for the optimised method is estimated at 5 microg m(-3) for NO2 and 6 microg m(-3) for SO2. Suitability of this passive sampling method for air pollution monitoring in urban areas was demonstrated by the results shown in this paper on a campaign carried out in the French agglomeration.

Air Pollutants↗

PubMed1996

Hierarchical cluster analysis of environmental pollutants through P450 induction in cultured hepatic cells.

Environmental pollutants are classically associated with increased drug metabolism. Cultures of rat hepatocytes, quail hepatocytes, and human hepatoma (Hep G2) cells were used to study the effects of pesticides on drug-metabolizing enzymes. Membrane integrity and mitochondrial activity were evaluated and induction of ethoxycoumarin-O-deethylase and ethoxyresorufin-O-deethylase activities were measured. Induced P450s were identified by immunoblotting. Pentachlorophenol and lindane appeared as the strongest inducers. On the immunoblots, specific antibodies revealed induced CYP1A1 in fetal rat hepatocytes, CYP2B in quail hepatocytes, and CYP3A7 in Hep G2 cells. Pesticide effects on these different activities in each type of cultured cells were compared by cluster analysis. Results obtained under similar conditions with reference inducers phenobarbital (PB) and benzo[a]anthracene and other environmental pollutants (polychlorobiphenyls) were added to previous data prior to multivariate analysis. The tested products fell into four major groups: a first group with pentachlorophenol, identified as a CYP3A inducer; a second group containing the methylcholanthrene-type inducers that increase CYP1A-related activities; a third class represented by dieldrin, a PB-type inducer; a fourth group including inert compounds or weak inducers. Lindane shares the criteria of the second and third groups and seems to induce both CYP1A and CYP2B activities. The current study results highlight the advantage of using several types of cultured hepatocytes to evaluate the short-term toxicity of environmental pollutants in vitro and constitute a useful model for predicting the potential toxicity of pesticides in humans (Hep G2 cells) and wildlife (fetal quail hepatocytes).

7-Alkoxycoumarin O-Dealkylase↗