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D Michard

Publications and source records attributed to D Michard.

5 recordsLinked to original sources
PubMed1998

Immunologic and renal markers among photogravure printers exposed to toluene.

OBJECTIVES: This study assessed immunologic and early renal effects of chronic toluene exposure. METHODS: In a longitudinal study of 92 printers and 74 referents, 145 subjects had pre- and poststudy samples of blood and urine taken for the following measurements: immunoglobulin E (IgE), antiglomerular basement membrane (anti-GBM) and antilaminin (anti-LAM) antibodies in blood; creatinine and beta2-microglobulin in blood and urine; and microalbumin, N-acetyl-b-D-glucosaminidase (NAG) and alanine-aminopeptidase in urine. Creatinine clearance was calculated according to the Cockroft-Gault formula. Eight-hour personal air samples were collected twice to assess present exposure to toluene. A job-exposure matrix was developed to estimate past cumulative exposure. Information about potential confounders was recorded by questionnaire. Multiple regression analysis was performed to study dose-effect relations adjusted for age and smoking. RESULTS: No subject was positive for anti-GBM antibodies, and only 12 were positive for anti-LAM. No relation was observed between the markers studied and present exposure to toluene except that creatinine clearance was higher among the exposed subjects than among the referents. A dose-response relation was observed between cumulative toluene exposure and both IgE and NAG excretion. No interaction was observed between hypertension and exposure, but the relationship with NAG did not persist when subjects with hypertension were excluded. Past or present exposure did not alter the 2-year trend of any marker studied. CONCLUSIONS: According to the results of this study, toluene at 50 ppm is not related to detectable renal dysfunction. The increased IgE levels associated with present and past exposure require further investigation.

Adult↗
PubMed1996

Food deprivation modifies fatty acid partitioning and beta-oxidation capacity in rat liver.

The involvement of lipids under starvation conditions in the shift from the phase of protein sparing (phase II) to the phase of increased protein breakdown (phase III) has been investigated. Plasma and liver were sampled from fed and unfed rats at two distinct stages which were characterized according to the changes in specific loss in daily body mass and nitrogen excretion. In the two groups of food-deprived rats corresponding to phases II and III, the liver concentration of triglycerides (micromol/g) was significantly lower, that of cholesterol significantly higher and that of the other lipid classes was moderately affected compared with concentrations in fed rats. Hepatic phospholipids had significantly higher concentrations (mol/100 mol) of 22:6(n-3) in food-deprived rats than in fed rats. Triglycerides had significantly higher concentrations of stearic and arachidonic acids in livers of both groups of food-deprived rats compared with fed rats. The total activity of carnitine palmitoyl transferase [mmol/(min x liver)] was 48% higher in rats studied at the end of phase II than in fed rats but was similar in fed rats and in rats studied at the beginning of phase III. The total activity of fatty acyl-CoA oxidase was 73% lower only in rats studied at the beginning of phase III when compared with fed rats. Our results indicate that during food deprivation the change in the rate of protein utilization is associated with important qualitative and quantitative alterations of hepatic lipids and oxidative capacity of fatty acids. These modifications appear to be related to the change from a preferential use of lipids to a preferential utilization of proteins.

3-Hydroxybutyric Acid↗
PubMed1995

[Early markers of nephrotoxicity: variation factors and reproducibility].

Epidemiological validity of early markers of nephrotoxicity currently used in occupational epidemiology has been poorly investigated. The aim of this study was to identify variation factors of these markers, to quantify their intra- and inter-individual variability and to evaluate the consequences of these results on study size and power. A cross-sectional survey was carried out in 1991 in a rotogravure plant including 168 male subjects (92 exposed to toluene and 76 controls). Blood and urine samples were taken twice: at study onset and one to five months later for 40% of the subjects. Creatinine and beta-2-microglobulin (beta 2M) were measured in both blood and urine; microalbumin (microALB), N-acetyl-beta-D-glucosaminidase (NAG), and alanine-aminopeptidase (AAP), in urine. Sources of physiological variation were reduced by standardization of collection and assay methods. Subjects completed a questionnaire to record information about their personal characteristics, alcohol, tobacco and drug consumption and their health. Statistical analysis of all subjects was adjusted for exposure status. Several factors were significantly related to the markers: age with beta 2M, NAG and AAP; smoking, alcohol drinking, and blood pressure with both microALB and NAG; urinary pH with beta 2M. These factors explained from 13 to 21% of the total variance of these markers. Short-term reproducibility, i.e. the correlation between the two measurements, was high for microALB (r = 0.75), moderate for NAG (r = 0.51), and low for beta 2M (r = 0.33) and AAP (r = 0.17). These results showed that confusion bias in the evaluation of exposure-marker association can be reduced by adjusting for several factors and that accuracy and study power can be improved by repeating measurements, especially for beta 2M and AAP.

Acetylglucosaminidase↗
PubMedDate not supplied

Color vision and occupational toluene exposure.

We examined the relationship between acquired color vision loss and exposure to toluene and total hydrocarbons among 125 male workers. Seventy-two toluene-exposed printers were compared with 34 workers from the same photogravure plant with ambient background exposure, and with 19 workers from a bookbinding plant located in the same town (nonexposed). Environmental mean toluene exposure level at workstation was estimated from individual 8-h sampling. Historic exposure data from the last 30 years were used to construct two cumulative exposure indices, one for toluene and one for total hydrocarbons. Airborne toluene levels were overall lower than the current Threshold Limit Value (TLV) of 50 ppm. Color vision was assessed by the Lanthony D-15 desaturated panel. Color vision loss was quantitatively established by the Color Confusion Index (CCI) and classified by type of acquired dyschromatopsia according to Verriest's classification. CCI was positively related to current airborne toluene levels, and cumulative exposure indices for toluene and total hydrocarbons (.18< or =r< or =.35). Odds ratios of acquired dyschromatopsia were significant for current airborne toluene, toluene, and total hydrocarbon past exposure (1.27 [1.02-1.58], 1.21 [1.04-1.39], 1.15 [1.02-1.31], respectively). In conclusion, this study suggests that the Lanthony D-15 desaturated panel detects early neurotoxic effects among workers exposed to toluene.

Adult↗