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Biomedical subjects

M Vanhoorne

Publications and source records attributed to M Vanhoorne.

At least 19 recordsLinked to original sources
PubMed2005

Is inhibin B involved in the toxic effect of lead on male reproduction?

Human studies indicate exposure to lead is associated with decreased sperm quality with modest, if any, effects on conventional reproductive endocrine profile. Inhibin B is a marker of Sertoli cell function and spermatogenesis. The present study evaluates possible effects of lead exposure on serum levels of inhibin B in a group of lead workers as compared with a non-exposed group of hospital personnel. The study population included 68 healthy Belgian workers from a lead smelter (Hoboken, Belgium) and for comparison a control group of 91 hospital personnel (University Hospital Ghent, Belgium). Semen analysis and measurement of current blood lead levels and serum levels of inhibin B, follicle stimulating hormone (FSH) and estradiol (E2). Lead workers had significantly lower sperm concentration (35 vs. 51 million/mL) and higher serum inhibin B (259 vs. 177 pg/mL) as well as lead blood levels 30.9 vs. 3.4 mug/dL) compared with the hospital personnel (all p < 0.05). Serum FSH and E2 levels were similar in both groups. Overall, inhibin B levels correlated significantly positively with blood lead levels and sperm concentration while it was negatively correlated with serum FSH. In multiple regression analysis of data from all participants, blood lead and serum FSH (p < 0.0001 for both) followed by sperm count (p = 0.007) were selected as the only independent variables for inhibin B with an R-adjusted coefficient of determination of 0.3714. The results of the present study suggest that the exposure of the cells of Sertoli to excessive amounts of lead results in inappropriate inhibin B overproduction that may be involved in the impairment of spermatogenesis.

Adult↗
PubMed2003

Time To Pregnancy and occupational lead exposure.

BACKGROUND: Lead exposure is known to be harmful to the male reproductive system, including impairment of fertility. However, it is unclear whether currently existing low levels of exposure have this effect. AIMS: To study retrospectively current workers in lead using industries (battery manufacture, smelting, etc), and in non-lead using control industries, in four European countries, with Time To Pregnancy as the outcome variable, as part of the EU funded Asclepios Project. METHODS: Exposure assessment was mainly by blood lead values, which were available from the late 1970s, supplemented by imputed values where necessary. Three exposure models were studied: (1) short term (recent) exposure; (2) total duration of work in a lead using industry; and (3) cumulative exposure. A Cox proportional hazards model with discrete ties was used for the statistical analysis, with covariates for both partners. RESULTS: A total of 1104 subjects took part, of whom 638 were occupationally exposed to lead at the relevant time. Blood lead levels were mainly less than 50 microg/dl. No consistent association of Time To Pregnancy with lead exposure was found in any of the exposure models, although reduced fertility was observed in one category each in models (2) and (3). CONCLUSIONS: This basically negative result is unlikely to be due to the misclassification of key variables, to insufficient statistical power, or to bias, for example, response bias. If any impairment of male reproductive function exists at the levels of occupational lead exposure now current, it does not appear to reduce biological fertility.

Cross-Sectional Studies↗
PubMed2002

Sperm count and chromatin structure in men exposed to inorganic lead: lowest adverse effect levels.

OBJECTIVES: To obtain knowledge on male reproductive toxicity of inorganic lead at current European exposure levels and to establish lowest adverse effect levels, if any. METHODS: A cross sectional survey of the semen of 503 men employed by 10 companies was conducted in the United Kingdom, Italy, and Belgium. The mean blood lead concentration was 31.0 microg/dl (range 4.6-64.5) in 362 workers exposed to lead and 4.4 microg/dl (range below the detection limit of 19.8) in 141 reference workers. Semen volume and sperm concentration were determined in a fresh semen sample according to an agreed protocol subject to quality assurance. The sperm chromatin structure assay (SCSA) was performed at a centralised laboratory. Extraneous determinants including centre, period of sexual abstinence, and age were taken into account in the statistical analysis. If appropriate, possible thresholds were examined by iterative threshold slope linear regression. RESULTS: The median sperm concentration was reduced by 49% in men with blood lead concentration above 50 microg/dl. There was no indication of a linear trend of lower sperm concentration with increasing blood lead values, but threshold slope least square regression identified a blood lead concentration of 44 microg/dl (beta=-0.037, F=4.35, p=0.038) as a likely threshold. Abnormal sperm chromatin structure was not related to blood lead concentration, but some indications of deterioration of sperm chromatin was found in men with the highest concentrations of lead within spermatozoa. Biological monitoring data did not indicate long term effects of lead on semen quantity or sperm chromatin. CONCLUSION: Adverse effects of lead on sperm concentration and susceptibility to acid induced denaturation of sperm chromatin are unlikely at blood lead concentrations below 45 microg/dl. Effects of low level exposure to lead on other measures of testicular function cannot be ruled out.

Adult↗
PubMed2001

The cross-sectional study of the health effects of occupational exposure to carbon disulfide in a Chinese viscose plant.

This article presents results of carbon disulfide exposure assessment in a Chinese viscose rayon factory and represents the cross-sectional study beginning phase of the occupational epidemiological project. The authors measured external exposure levels to carbon disulfide at a Chinese viscose rayon factory and monitored results as internal exposure indexes by testing urine samples of workers exposed to carbon disulfide levels. The rate at which carbon disulfide is metabolized by exposed subjects was demonstrated by 2-thio-thiazolidine-4-carboxylic acid (TTCA) concentrations in urine of exposed subjects, which was studied to determine best time points for internal exposure sampling. Carbon disulfide concentrations in the air of the workplace were analyzed with gas chromatography with flame photometric detector (GC-FPD); presence of TTCA in urine samples of subjects was determined using a modified high-performance liquid chromatography method. Kinetics of TTCA excretion was studied by analysis at different time points during and after exposure of workers to carbon disulfide. A total of 155 personal samples were obtained. Carbon disulfide concentration at staple viscose hall was found to be 13.72 +/- 1.12 mg/m3 in terms of geometric mean and geometric standard deviation. Carbon disulfide concentration at filament spinning hall was found to be 20.05 +/- 1.33 mg/m3. TTCA values of subjects at staple spinning hall were 1.18 +/- 0.43 and 1.07 +/- 0.38 mg/g creatinine for subjects working at filament spinning hall. The best time for TTCA sampling is at the end of the exposure-working shift.

Adult↗
PubMed2001

Carbon disulfide exposure assessment in a Chinese viscose filament plant.

UNLABELLED: Carbon disulfide is a well-known occupational hazard in the viscose industry, and studies have shown considerable health effects when workers are exposed to high concentrations of this reagent. At exposure levels below the TLV-TWA(31 mg/m3), findings remain contradictory, probably due to deficient exposure data. The present study tries to identify the occupational hazards and thoroughly assess the exposure levels in a Chinese viscose rayon plant. METHODS: An industrial hygienic field survey and a sampling campaign were carried out, including multi-gas monitoring, on-line measurements, and stationary assessment in the spinning hall as well as personal exposure sampling for spinners (by charcoal tube absorbing and GC-FPD analysis). All data was introduced into Foxpro database, and analyzed by Epi info (6.04) and SPSS. RESULTS: On-line measurement showed that the geometric mean (GM) of carbon disulfide exposure amounted to 12.73 mg/m3 in 'exposure' and 0.08 mg/m3 in 'non-exposure' worksites. These concentrations in the air were related to the subject's activities showing the highest levels when they had to open the shield windows of the spinning machines. Stationary exposure measurements of carbon disulfide in the spinning hall amounted to 23.29 mg/m3 GM (range 5.8-97.94 mg/m3). Personal exposure of spinners was about 17.3 mg/m3 GM. Comparing these methods, the personal exposure sampling could exactly express the exposure levels of the worker's contacting situation. The on-line measurement by multi-gas monitor might also be recommended to the factory as it has its own advantages of rapid and independent assessment, but it under-estimates the exposure level.

Air Pollution, Indoor↗
PubMed2001

Decreased carotid artery distensibility as a sign of early atherosclerosis in viscose rayon workers.

Carbon disulphide (CS(2)) is known to accelerate atherosclerosis and to increase the risk for cardiovascular diseases. To assess the effect of CS(2) on the functional (distensibility and compliance) and the structural (intima media thickness) properties of the common carotid artery, and blood pressure and lipid metabolism parameters, a cross-sectional study on 85 workers from a viscose rayon factory and 37 controls was carried out. Exposure to CS(2) was assessed by personal monitoring and was well below the threshold limit value-time weighted average. Carotid arterial wall properties were determined using a non-invasive ultrasound wall movement detector system. No significant effect of CS(2) on blood pressure, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol or triglycerides was found. Among the vascular parameters studied, only distensibility was significantly lower and heart rate was significantly higher in exposed subjects compared with the controls. In conclusion, occupational exposure to CS(2) may cause early alterations in arterial elastic properties in young individuals, and even before lipid and clinical findings have occurred, important functional changes in the vessel wall are present.

Adult↗
PubMed2001

Vascular changes in workers exposed to carbon disulfide.

AIM: To assess the effects of occupational exposure to carbon disulfide (CS2) concentrations below the threshold limit value (31 mg/m3) on the structural and the functional properties of the arteries, heart rate, blood pressure and lipids. METHODS: Study subjects were 85 male workers in the viscose industry and 35 men without such exposure. The CS2 concentration was determined by personal active sampling. From the common carotid artery diameter, the change in diameter (echography) during the heart cycle and the pulse pressure, local arterial distensibility and compliance were calculated. Global large and small artery elasticity were calculated from registrations of radial artery waveforms. Simultaneously, heart rate and blood pressure were recorded and blood samples were collected for lipid measurements. RESULTS: CS2 concentrations ranged from 2.34 to 32.4 mg/m3. No significant effect of CS2 on blood pressure, total cholesterol, HDL and LDL cholesterol or triglycerides was found. Among the vascular parameters under study, common carotid artery distensibility was significantly lower, and heart rate significantly higher in exposed workers compared to controls. The differences remained significant after adjustment for age, body mass index, smoking habits, alcohol consumption, heart rate and systolic blood pressure. Common carotid artery intima media thickness and global arterial indices did not differ significantly between the two groups. CONCLUSIONS: Exposure to CS2 under the current level may already cause alterations in common carotid artery elastic properties in apparently healthy individuals. Even before biochemical and clinical findings occur, important functional changes in the vessel wall were observed, at least in some vascular territories.

Adult↗
PubMed2000

Carbon disulfide at a Chinese viscose factory external and internal exposure assessment.

This article presents the results of carbon disulfide exposure measurements in a Chinese viscose rayon factory. The objectives of the study were to identify the external exposure levels at a large factory and to investigate the 2-thiothiazolidine-4-carboxylic acid (TTCA) concentrations in the urine of the subjects who were exposed to carbon disulfide in the working place atmosphere. The metabolism of carbon disulfide in the exposed subjects was also studied in order to demonstrate the best points in time for the internal exposure sampling. The measurement of the amount of personal exposure to carbon disulfide in the air of the workplace was performed by GC-FPD; the presence of TTCA in the workers urine was analyzed by use of a modified HPLC method. The kinetics of TTCA excretion was studied by analyses at different time-points both during and after exposure to carbon disulfide in the subjects. A total of 155 personal samples were obtained. The carbon disulfide concentration in the staple viscose hall was 13.72 +/- 1.12 mg m-3 in terms of the geometric mean +/- geometric standard deviation, and was 20.05 +/- 1.33 mg m-3 in the filament spinning hall. The TTCA values in the subjects who worked in the staple spinning hall were 1.18 +/- 0.43 mg g-1 creatinine and 1.07 +/- 0.38 mg g-1 creatinine for subjects working in the filament spinning hall. The best time for TTCA sampling is at the end of the working shift, the TTCA excretion was stable for a period of 4-12 h after exposure of the subjects to the carbon disulfide. It might be that the Chinese have different anthropometric characteristics; a sampling bias may therefore appear among different races.

Adult↗
PubMed1999

Preliminary external quality assessment for the biological monitoring of carbon disulfide with urinary 2-thiothiazolidine-4-carboxylic acid.

Four laboratories have participated in an external quality control assessment for the determination of 2-thiothiazolidine-4-carboxylic acid (TTCA). TTCA is used as a biomarker for exposure to CS2. Thirteen different urine samples were analyzed by each laboratory. Ten of these were spiked with known amounts of TTCA, and had either a high or intermediate creatinine content. Two samples without any TTCA were used as controls and one sample was a pool of samples of urine from five employees occupationally exposed to CS2. The latter had unknown TTCA content. For each sample, TTCA and creatinine concentration were determined. The samples were supplied in three consecutive deliveries. Several samples were offered more than once. Thus, within-laboratory variability could be established for creatinine and TTCA determination and accuracy could be determined for TTCA analysis. Within-laboratory variability was low for all laboratories for creatinine, although laboratory D seemed to have a slight downward bias. Accuracy for TTCA was good for all laboratories. No significant mean deviation from the expected TTCA value was encountered. There does not seem to be any clear influence of the TTCA concentration level of the samples on the accuracy and within-laboratory variability. Two of the four laboratories (A and C) showed lower within-laboratory variability than the other two for TTCA, although coefficients of variation between replicated samples are high for these two laboratories as well. The laboratory giving the best accuracy, gave the highest within-laboratory variability. A non-systematic, random error is probably the source of this. The results of this preliminary study indicate that analysis of TTCA, although regarded as an established biomarker, can give biases and thus negatively interfere with inferred dose-effect or dose-response relationships in occupational epidemiology.

Bias↗
PubMed1999

Objectives, designs and populations of the European Asclepios study on occupational hazards to male reproductive capability.

The main objective of the Asclepios program was to examine occupational risk factors for the male reproductive system. The program focused on occupational exposure to fungicides (farmers, greenhouse workers, and vineyard workers), styrene (laminators in the reinforced plastics industry) and inorganic lead (battery workers, foundry workers, and lead smelters). Questionnaire studies of time to pregnancy were combined with longitudinal and cross-sectional studies of semen quality. The 8 data-collecting centers addressed 6553 male workers and contributed time-to-pregnancy values on the 3077 most recent pregnancies. Data collection was by interview or self-collection. The average response rate across all exposures and centers was 69.8%. The Asclepios project is the first international multicenter research project on environmental risks to male reproductive function. A protocol for epidemiologic research on occupational risk factors to the male reproductive system was developed, and links between epidemiologic and experimental units were established. The majority, but not all, of the studies was completed within the given time frame.

Adult↗
PubMed1998

Male reproductive toxicity of lead in animals and humans. ASCLEPIOS Study Group.

OBJECTIVE: To critically review the literature on male reproductive toxicity of lead in animals and humans. METHODS: A systematic literature search identified a total of 32 experimental studies in animals and 22 epidemiological studies, one case report on humans and five review articles or documents. The studies were evaluated by paying attention mainly to sample size, study design, exposure, and dose characterisation, analytical method standardisation, and quality assurance. RESULTS: Several studies on rats and other rodents indicated that blood lead concentrations > 30-40 micrograms/dl were associated with impairment of spermatogenesis and reduced concentrations of androgens. However, other animal studies, mainly about histopathological, spermatozoal, and hormonal end points, indicated that certain species and strains were quite resistant to the reproductive toxicity of lead and that different testicular lead concentrations could account for these differences. The human studies focused mainly on semen quality, endocrine function, and birth rates in occupationally exposed subjects, and showed that exposure to concentrations of inorganic lead > 40 micrograms/dl in blood impaired male reproductive function by reducing sperm count, volume, and density, or changing sperm motility and morphology. No relevant effects were detected on endocrine profile. CONCLUSION: Several factors make it difficult to extrapolate the animal data to the human situation. The difficulties are mainly due to differences between species in reproductive end points and to the level of exposure. Concentrations of blood lead > 40 micrograms/dl seemed to be associated with a decrease in sperm count, volume, motility, and morphological alterations and a possible modest effect on endocrine profile. Dose-response relation, in particular at a threshold level, is poorly understood, and site, mode, or mechanism of action are unknown. Also, the effects were not always the same or associated in the same on sperm count and concentration. Some methodological issues and indications for future studies are discussed.

Animals↗
PubMed1995

Epidemiological study of eye irritation by hydrogen sulphide and/or carbon disulphide exposure in viscose rayon workers.

In the framework of an extensive health survey 123 male viscose rayon workers exposed to hydrogen sulphide (H2S) and/or carbon disulphide (CS2) and 67 referents not exposed to either of these chemicals answered questions on eye irritation complaints in a self-administered questionnaire. Personal exposure varied from 4 to 112 mg m-3 for CS2 and from 0.2 to 8.9 mg m-3 for H2S. A combined exposure measure was calculated using principal component analysis. The exposed subjects had a significantly higher prevalence of eye pain, burning and photophobia. Adjustment for age and smoking in logistic regression revealed significantly more eye complaints for all workers that were highly exposed. In a postal survey one-third of the ex-workers of the same viscose rayon factory reported having left the factory because of eye complaints, indicating that their occurrence may be underestimated in the cross-sectional study.

Adult↗
PubMed1992

Epidemiological study of gastrointestinal and liver effects of carbon disulfide.

In the framework of an extensive health survey, 119 viscose rayon workers exposed to carbon disulfide (CS2) and 79 workers from other plants not exposed to any toxic agent in the working environment underwent a gastrointestinal examination including a self-administered questionnaire, abdominal palpation, percussion and a number of liver function tests. In the viscose rayon factory the working conditions have not changed since 1932. Personal monitoring performed in 17 jobs showed CS2 exposures varying from 4 to 112 mg.m-3. For each individual a cumulative CS2 exposure index (CS2 index) was calculated. Univariate analysis of the questionnaire findings showed significantly higher prevalences of anorexia (37.0% vs 11.4%, P less than 0.0001), vomiting (12.6% vs 3.8%, P = 0.04), and recent weight loss (10.9% vs 1.3%, P = 0.009) in the exposed than in the non-exposed workers. The exposed workers had a larger total number of gastrointestinal complaints and a larger proportion reported at least one complaint at least once a month than the non-exposed ones. Abdominal tenderness was very rare in both groups. In multiple logistic regression analysis, adjusting for alcohol intake, smoking, body mass index (BMI), coffee consumption, commuting time, stress at work, shift work, educational level, family history of ulcer disease and intake of medication, significant associations with exposure were found for anorexia (P = 0.0001), nausea (P = 0.009), vomiting (P = 0.002) and flatulence (P = 0.03). Stress at work was a determinant for quite a few digestive complaints, but shift work was not significantly associated with any of them.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Use of pharmaceuticals in industrial workers--possible implications for epidemiological studies.

A total of 129 workers exposed to carbon disulphide (CS2) and 81 non-exposed controls were asked about their current use of pharmaceuticals, using a self-administered questionnaire. In all, 31% of the exposed and 19.8% of the non-exposed used some medicine (P = 0.08). The average number of pharmaceuticals per subject amounted to 0.71 in the exposed vs. 0.36 in the non-exposed (P = 0.049). Predominant types of medicines used were analgesics (12.4% in the exposed vs. 8.6% in the non-exposed, P = 0.50) and sedatives/hypnotics (10.1% in the exposed vs. 4.9% in the non-exposed, P = 0.21). The pharmaceuticals consumed can cause numerous (side) effects that are similar to the toxic effects of CS2. To take into account these possibly confounding agents, a classification system for possible (side) effects of pharmaceuticals was developed, taking the dose into account. According to this method, many (side) effects of pharmaceuticals that could occur were recorded with higher frequency and intensity in the exposed subjects. Potential (side) effects that occurred significantly more frequently in the exposed than in the non-exposed were: tiredness, sedation, dizziness (20.9% vs. 4.9%, P = 0.001), excitation, anxiety (10.9% vs. 2.5%, P = 0.03), vision disturbances (7.0% vs. 0%, P = 0.01), and erection decrease (5.4% vs. 0%, P = 0.045). The implications of these findings for epidemiological studies are discussed.

Adult↗
PubMed1992

Epidemiological study of the cardiovascular effects of carbon disulphide.

In an extensive health survey 115 male viscose rayon workers exposed to carbon disulphide (CS2) and 76 referents not exposed to this chemical were interviewed using the WHO cardiovascular questionnaire and responded to a self-administered questionnaire. A 12-lead ECG was taken and coded using the Minnesota code. Blood pressure (BP) was measured electronically and blood was examined for lipoproteins. In the viscose rayon factory the working conditions had not changed since 1932. Personal monitoring performed in 17 jobs, showed exposures varying from 4 to 112 mg/m3. For each individual a CS2 cumulative exposure index (CS2 index) was calculated. There were no significant differences between exposed and referents concerning the prevalence of angina, history of myocardial infarction, intermittent claudication and ECG signs of ischaemia. Blood pressure, low density lipoprotein (LDL)-cholesterol and the apolipoproteins A1 and B rose while high density lipoprotein (HDL)-cholesterol, the HDL-cholesterol/apolipoprotein A1 and the LDL-cholesterol/apolipoprotein B ratios decreased significantly with increasing exposure. Adjustment for age, body mass index, smoking, alcohol consumption, stress and tension at work, shift work, noise exposure and educational level in multiple linear regression analysis showed significant effects of the CS2 index on systolic BP, diastolic BP, cholesterol, HDL-cholesterol, LDL-cholesterol, apolipoprotein A1, apolipoprotein B, the LDL cholesterol/apolipoprotein B and HDL cholesterol/apolipoprotein A1 ratios; there were no significant effects on the triglycerides.

Adult↗
PubMed1991

Survey of chemical exposures in a viscose rayon plant.

Measurements of carbon disulphide and hydrogen sulphide in a Belgian viscose rayon plant, using personal monitoring with charcoal tubes for carbon disulphide and impingers for hydrogen sulphide, showed considerable differences in the average exposure for the different jobs (3-147 mg m-3 for carbon disulphide and 0-9 mg m-3 for hydrogen sulphide). Air pollutants such as mercury and sulphuric acid, which have been reported in some other studies, were not present. The lead in blood concentration found in four plumbers ranged from 28 to 49 micrograms 100 ml-1. The implications of these findings for industrial hygiene and epidemiology are discussed.

Air Pollutants, Occupational↗
PubMed1990

Accumulation of carbon disulphide metabolites.

Biological monitoring for carbon disulphide (CS2) exposure performed using the iodine-azide test (IAT) and 2-thiothiazolidine-4-carboxylic acid (TTCA) test in urinalysis of workers with high exposure to CS2 (112-142 mg/m3, n = 34), workers with low exposure (4-7 mg/m3, n = 16), and non-exposed university workers (n = 10). Pre-shift and post-shift urine specimens were collected on three consecutive days in the exposed and for only one day in the non-exposed. According to the findings the specificity and the sensitivity seem to be low for the IAT and high for the TTCA test. Contrary to a previous report all pre-shift urine samples showed negative IATs. The TTCA test was positive in pre-shift urine even after 32 to 63.5 h without exposure, and values tended to increase during consecutive days of exposure in highly exposed workers. The possible health implications of these findings should be further investigated.

Air Pollutants, Occupational↗