Metal enriched quasi-ultrafine particles from stainless steel gas metal arc welding induced genetic and epigenetic alterations in BEAS-2B cells

Recent evidence has supported welding fume (WF)-derived ultrafine particles (UFP) could be the driving force of their adverse health effects. However, UFP have not yet been extensively studied and are currently not included in present air quality standards/guidelines. Here, attention was focused on the underlying genetic and epigenetic mechanisms by which the quasi-UFP (Q-UFP, i.e., ≤ 0.25 μm) of the WF emitted by gas metal arc welding-stainless steel (GMAW-SS) exert their toxicity in human bronchial epithelial BEAS-2B cells. The Q-UFP under study showed a monomodal size distribution in number centered on 104.4 ± 52.3 nm and a zeta potential of -13.8 ± 0.3 mV. They were enriched in Fe > Cr > Mn > Si, and displayed a relatively high intrinsic oxidative potential. Dose-dependent activation of nuclear factor erythroid 2-related factor 2 and nuclear factor-kappa B signaling pathway, glutathione alteration, and DNA, protein and lipid oxidative damage were reported in BEAS-2B cells acutely (1.5 and 9 μg/cm², 24 h) or repeatedly (0.25 and 1.5 μg/cm², 3 × 24 h) exposed to Q-UFP (p < 0.05). Alterations of the Histone H3 acetylation were reported for any exposure (p < 0.05). Differentially regulated miRNA and mRNA indicated the activation of some critical cell signaling pathways related to oxidative stress, inflammation, and cell cycle deregulation towards apoptosis. Taken together, these results highlighted the urgent need to better evaluate the respective toxicity of the different metals and to include the Q-UFP fraction of WF in current air quality standards/guidelines relevant to the occupational settings.

[Assessment of occupational exposure to ortho-toluidine using gas chromatography-mass spectrometry]

Ortho-toluidine is a carcinogen aromatic amine. It is in part eliminated as unchanged form and its urine determination allows biologic monitoriing of occupational exposure. We propose a new method simple and fast in gas chromatography mass spectrometry. In the Nord-Pas-de-Calais region, a company initiated destruction and depollution of an old industrialsite.The GS-MS method permits exposition evaluation of workers employed in demolition of a liquid SO2 plant polluted with ortho-toluidine. This plant has been stopped twenty years ago. These results are compared with results of workers without any exposure in the same company. A 5 mL urine sample spiked with internal standard (ortho-toluidine D9) is extracted with hexane. Derivatisation is achieved with anhydrous pentafluoropropionic acid during 30 min at 60 degrees C. Chromatographic separation is performed on a BPX5MS column (25 m x 0.25 mm, 0.25 microm; SGE). Initial column temperature (60 degrees C) is hold 3 min then is raised to 300 degrees C at 25 degrees C/min. Detection is performed with mass spectrometry with negative chemical ionisation with methane. Acquisition is performed in single ion monitoring. Identification ions are 233 ion (m/z) and 213 ion (m/z) with 233 (m/z) used for quantification. Linearity of the method is verified between 0.1 and 100 microg/L. The limit of detection is 0.02 micro/L. Repeatability and intermediate fidelity are satisfactory (CV < 9%). For unexposed workers, urinary concentrations of ortho-toluidine ranged between 0.17 microg/L and 2.46 microg/g creatinine. Urinary concentrations for exposed workers ranged between 26.14 and 462.00 microg/g creatinine and after new action of protection between 2.35 et 20.11 microg/g creatinine. This new GC-MS method is specific and sensitive and allows for urinary determination of ortho-toluidine. Results showed that this method is adapted for biomonitoring as much for unexposed workers to this aromatic amine as for exposed workers.

Urinary homovanillic acid and serum prolactin levels in children with low environmental exposure to lead

Current evidence suggests that the neurotoxic effects of lead may partially be mediated through interference with the dopaminergic system. The aim of this study was to assess the levels of two peripheral dopaminergic markers--serum prolactin (Pro-S) and urinary homovanillic acid (HVA-U)--in children living around two lead smelters, who are presumed to be exposed to high environmental lead pollution (n = 200), and compare their results with 200 age- and sex-matched controls living in an area unpolluted by heavy metals, giving a total of 400 children (200 boys and 200 girls). The influence of lead exposure on HVA-U and Pro-S was assessed by stepwise multiple regression, testing lead concentrations in blood (Pb-B), age, sex and area of residence as predictors. Though lead levels were significantly higher in boys and in the lead-polluted environment, mean Pb-B values were relatively low, indicating a low uptake of lead in the contaminated environment (39.5 micrograms l-1, range 4.6-165 micrograms l-1, n = 200), and no significant correlation could be found with either Pro-S or HVA-U. However, when the subgroup of 121 children with Pb-B levels above 50 micrograms l-1 were considered, a weak positive correlation was found between Pb-B and HVA-U (r2 = 0.04, p = 0.03), whilst in the even smaller subgroup of 15 children with Pb-B levels above 100 micrograms l-1, Pro-S appeared to be positively correlated with Pb-B, though the numbers of children were too small for the correlation to reach statistical significance (p = 0.095). These weak associations, probably not important in biological terms, indicate that Pro-S and HVA-U are not useful biomarkers at present exposure levels to lead in the environment. Nevertheless, the finding of subtle biochemical alterations in the dopaminergic system at Pb-B levels of around 100 micrograms l-1 supports the recommended setting of the action level at this value.

Determinants of cadmium burden levels in a population of children living in the vicinity of nonferrous smelters

This report covers part of the assessment of a site in northern France polluted by industrial metal emissions. Our objectives were to assess the cadmium burden in children aged 8 to 11 years and look for factors that affected it. A cross-sectional population-based study took place in 1996-1997 and included 400 children (200 in the metal-polluted area). The geometric mean of the blood cadmium (CdB) levels of children living on the polluted site was 0.51 microg/L (95% CI=[0.49-0.53]); that of the nonexposed children was 0.47 microg/L (95% CI=[0.45-0.49]) (P<0.01). The geometric mean of the urinary cadmium (CdU) levels of children living on the polluted site was 1.16 microg/g creatinine (95% CI=[1.01-1.34]); that of the nonexposed children was 0.99 microg/g creatinine (95% CI=[0.86-1.14]) (P=0.10). Mean CdB was higher among children within 4 km of a zinc smelter and consuming > or =500 ml of tap water daily (x1.34; 95% CI=[1.14-1.51]) compared with children living more than 4 km away and consuming <500 ml of tap water daily. Independently of this association, consumption of fish and shellfish (> or =once a week vs. <once a week) and homegrown vegetables (> or =once daily vs. <once daily) was associated with higher mean CdB levels, respectively: x 1.14; 95% CI=[1.07-1.21] and x 1.25; 95% CI=[1.04-1.50]. Neither sex nor age was associated with CdB. Mean CdU was associated with paternal occupational cadmium exposure.

[Epidemiology of soft tissue sarcomas in adults]

INCIDENCE

Soft tissue sarcoma accounts for a approximately 1% of all cancers. Excluding Kaposi sarcoma, the incidence of soft tissue sarcoma has remained stable in Europe (3-4/100,000). ENDOGENOUS FACTORS: Endogenous factors are related to rare genetic syndromes (Li-Fraumeni syndrome, neurofibromatosis, Werner syndrome, bilateral retinoblastom). EXOGENOUS FACTORS: Exogenous factors associated with soft tissue sarcoma are essentially iatrogenic: radiation therapy (prevalence of radiation-induced sarcoma: 0.17-0.21%) and chronically edematous arms after radical mastectomy for breast cancer (Stewart-Treves syndrome). Many studies suggest that environmental or occupational exposure to chlorophenol, phenoxy-herbicides or dioxin increase the risk of soft tissue sarcoma. FURTHER RESEARCH: Little is known about the epidemiology of soft tissue sarcoma. Case-control studies are needed.

Occupational and environmental risk factors of the myelodysplastic syndromes in the North of France

Aetiological factors of the myelodysplastic syndromes (MDS) are largely unknown, with the exception of alkylating agents, ionizing radiation and benzene. Some other risk factors have been suggested by the few epidemiological studies reported (solvents, ammonia, exhaust gases, metals, pesticides, alcohol). We performed a case-control study to assess the relationship between occupational or environmental factors and MDS. Two hundred and four patients with newly diagnosed MDS, and 204 sex- and age-matched controls were included. Medical history, demographic data, lifetime exposure and hobbies were obtained. Qualitative and quantitative exposure to chemical and physical hazards were evaluated with the patients and reviewed by a group of experts in occupational exposure. The median age was 70 years and 62% of the patients were men. In univariate analyses, we found relationships between MDS and smoking habits, gardening, occupations such as health professionals, technical and sale representatives, machine operators, agricultural workers, textile workers, qualitative occupational exposures (exposed/non-exposed) to oil, solvents, ammonia, pesticides, fertilizers, cereal dusts, contact with poultry or livestock and infective risk, and lifetime cumulative exposure to solvents, oil, textile dust and infective risk. The main risk factors of MDS determined by multivariate analyses (conditional logistic regression) were, being an agricultural worker [odds ratio (OR) = 3.66; 95% confidence interval (CI) 1.9-7.0], textile operator (OR = 3.66; 95% CI 1.9-7.9), health professional (OR = 10.0; 95% CI 2.1-48.7), commercial and technical sale representative (OR = 4.45; 95% CI 1.4-14.6), machine operator (OR = 2.69; 95% CI 1.2-6.0), living next to an industrial plant (OR = 2.45; 95% CI 1.5-4.1), smoking (OR = 1.74; 95% CI 1.1-2.7) and lifetime cumulative exposure to oil (OR = 1.1; 95% CI 1.0-1.2). Further studies should be performed to assess specific exposures more precisely and it would be of interest to develop a map of haematological malignancies according to industrial background.

Environmental exposure to lead in a population of adults living in northern France: lead burden levels and their determinants

As part of the assessment of a site in northern France polluted by metals from two smelters (in particular, lead, cadmium and mercury), a cross-sectional study was carried out which intended to estimate the levels of the lead burden of the adult population living on the site and the factors associated with these levels. The exposed zone included 10 municipalities in the Nord-Pas de Calais region, located in the vicinity of two non-ferrous metal smelters. The soils in these municipalities contained between 100 and 1700 ppm of lead. The non-polluted zone contained 20 municipalities from the same region, drawn randomly from those in the region of comparable size but free from any industrial lead exposure. The adult study population (301 men and 300 women) was stratified according to age, sex, employment status and exposure level. The inclusion criteria required subjects who were aged between 20 and 50 years and had been living in the exposed zone for at least 8 years; the exclusion criteria were pregnancy, cancer, kidney disease and diabetes. No more than 10% of the subjects participating could work at one of the two smelters. Data collection took place at home; visiting nurses interviewed subjects to complete a questionnaire and also took blood samples. The lead assay was performed by atomic absorption spectrometry. The geometric mean of the blood-lead levels was 74 microg/l, 95% CI = 69-80 among men and 49 microg/l, 95% CI = 46-53 among women. Blood-lead levels exceeding 100 microg/l were found among 30% of men and 12% of women. Several factors were associated with variation of the mean blood-lead level: the blood-lead level was significantly higher among the men for subjects living less than 1 km from the smelters (geometric mean x 1.3, 95% CI = 1.1-1.6), for those who drink alcoholic beverages (x 1.1, 95% CI = 1.0-1.2 for consumption of 30 g/day), those who smoke (x 1.2, 95% CI = 1.0-1.3 for 20 cigarettes/day), and for subjects with occupational exposure; among the women, for subjects living less than 1 km from the smelters (geometric mean x 1.5, 95% CI = 1.2-1.7), for those who drink alcohol (x 1.1, 95% CI = 1.1-1.2 for a daily consumption of 10 g), and for women living in a building constructed before 1948 (x 1.2, 95% CI = 1.0-1.4).

Environmental lead exposure in a population of children in northern France: factors affecting lead burden

BACKGROUND

This study is part of the assessment of a site in northern France polluted by lead from industrial emissions. Our objectives were to look for the factors that influence lead burden in children aged 8-11 years.

METHODS

A cross-sectional population-based study took place in 1996-97 and included 400 children (200 of whom lived on the metal-polluted site).

RESULTS

The geometric mean of the blood-lead levels of children living on the polluted site was 39.5 microg/l (95% CI = 36.3-43.1); that of the non-exposed children was 30.6 microg/l (95% CI = 27.8-33.6) (P < 0.0001). Analysis of the variations in the mean blood-lead levels showed associations with: distance from the smelting plants (mean blood-lead level fell by a factor of 1/1.3 (95% CI = 1/1.2-1/1.4) for each km from the smelter over the range of 1-3 km and was constant thereafter) and consumption of tap water (when the water pipes were made of lead, the mean blood-lead level of children who drank tap water was twice as high (95% CI = 1.2-3.4) as that of children who did not).

CONCLUSIONS

The children's blood-lead levels were essentially linked to two factors: proximity to the smelters and drinking tap rather than bottled water.

Glutathione S transferase theta 1 gene defects in myelodysplastic syndromes and their correlation with karyotype and exposure to potential carcinogens

Glutathione S transferase theta 1 (GSTT1) is implicated in the detoxification of different substances, including carcinogens. Recently, an increased incidence of GSTT1 null genotype was found in myelodysplastic syndromes (MDS) by comparison with a control population. We analyzed GSTT1 gene by PCR in 174 MDS cases and 100 controls. The incidence of GSTT1 null genotype was 22% in MDS in 19% in controls (P = 0.53). The incidence of GSTT1 null genotype in MDS did not differ according to gender, FAB classification, karyotype and whether MDS were therapy related or 'de novo'. In 86 of the de novo cases, data on previous occupational and environmental exposure to a list of 170 substances were available. In those MDS patients, a significantly lower frequency of GSTT1 null genotype was seen in cases with previous jobs exposed to chemicals, and with previous exposure to mineral dusts and exhaust gases. A lower frequency (but with only borderline significance) was seen in MDS patients who had been coal miners and those who had been exposed to any of the 70 substances analyzed. Overall, GSTT1 null genotype occurred at a similar incidence (19%) in controls and in MDS cases previously exposed to any substance, but tended to be higher in unexposed MDS patients (40%, P = 0.07). Our results do not confirm the higher incidence of GSTT1 null genotype observed in MDS. The lower incidence of GSTT1 null genotype in MDS cases exposed to some compounds previously found associated with MDS is apparently unexpected. However, it could be explained by the fact that GSTT1 enzyme, which has a detoxification role for some compounds, could also have an activating role for other substances, including solvents.

[Etiological factors of myelodysplastic syndromes]

Specific epidemiologic data on myelodysplastic syndromes are rare. Analysis of data is in fact affected by problems of terminology and classification. The link between the exposure to ionizing radiation or alkylating agents and MDS is well established. Etiologic factors of acute leukemia, or new factors such as non ionizing radiation, solvent, ethylene oxide, glycol eters, tobacco smoke, exhaust gases, agricultural work have been hypothesized but should be confirmed by other studies on MDS.

Dose-dependent elimination kinetics for mercury in urine: observations in subjects with brief but high-level exposure

OBJECTIVES

To study the elimination kinetics for mercury in urine (U-Hg) after brief but high-level exposure.

METHODS

U-Hg was examined in 11 workers after 2-10 days of exposure to inorganic Hg and after symptoms and signs of Hg intoxication had appeared. Initial U-Hg excretion varied between 60 and 2360 micrograms/g creatinine. The subjects were followed up for 1-11 months. In each subject, one- and two-compartment models were fitted to the U-Hg values, assuming an exponential decrease, by weighted non-linear least-squares regression (weight = 1/U-Hg).

RESULTS

The data indicated two elimination phases in subjects with initial U-Hg above 600 micrograms/g. In the two-compartment models, there was a fast phase with a half-time of 2-16 days, and a slow phase with a half-time of more than a month. The fast phase contributed 70-90% to the sum of the Y intercepts.

CONCLUSIONS

The kinetics of U-Hg excretion after cessation of exposure seems to be dose-dependent and, at least in certain cases, to have two phases. The explanation for the fast phase may be that the capacity of certain binding sites in the kidney was exceeded.

Exposure to occupational and environmental factors in myelodysplastic syndromes. Preliminary results of a case-control study

We performed a case-control study of occupational and environmental risk factors in myelodysplastic syndromes (MDS) diagnosed at our institution, using the method of Siemiatycki. A control for each MDS case, matched for age, sex, and residence area was chosen. The questionnaire asked demographic data, medical history, and information on life-time environmental and occupational exposures. Occupational exposures were first assessed by job titles, then by evaluating exposure to a list of 70 chemicals, and the level and duration of exposure to those chemicals (exposure index). In the first 100 cases and controls analyzed, a significantly higher incidence of smokers or ex-smokers was seen in MDS cases (odds ratio, OR = 1.83, P = 0.03). A significant excess of MDS was found in male patients with jobs (or previous jobs) generally exposing to chemical compounds, including plant and machine operators and assemblers (odds ratio, OR = 3.73, P = 0.014) whereas, on the contrary, technicians and associate professionals were more often seen in controls (OR = 0.17, P = 0.002). In males, there was also a trend for more skilled agricultural workers and coal miners in MDS cases. In females, there was a non-significant trend for more professionals in controls. After adjusting for sex, age and smoking habits, significantly more frequent exposure to stone dusts (OR = 3.06, P = 0.011), and cereal dusts (OR = 2.27, P = 0.04) was found. There was also a trend for higher incidence of exposure to exhaust gases and nitro-organic explosives. In addition, significantly higher exposure indices to petrol and diesel derivatives (P = 0.03) and to fertilizers (P = 0.003) were seen in MDS cases, as compared to controls. No significant difference in exposure to other chemicals was seen between MDS cases and controls. These preliminary results of our study, which is accruing more cases, suggest, as two previously published case-control studies of risk factors in MDS, that exposure to some chemicals may be involved in the pathogenesis of MDS.

Adverse cardiovascular effects of anti-arrhythmia drugs. Part II: Inotropic effects and specific pharmacokinetic properties

The antiarrhythmic drugs are unfortunately not devoid of adverse effects. A good watching of their safety is necessary, according to their cardiovascular adverse effects which are the most dreaded. Among these and beside the proarrhythmic effects, the negative inotropic effects can impair cardiac function. Different mechanisms could explain the negative inotropic effects of antiarrhythmic drugs: reduction of adrenergic sensitivity, decrease of calcium concentration in the cardiac cells. Pharmacokinetic properties of antiarrhythmic drugs can modulate their cardiovascular adverse effects. As a matter of fact the plasmatic concentration of the unbound drug, which could be correlated to the adverse effects, fluctuates according to the protein binding of the drug. In an other way the first pass hepatic effect of a drug can be saturable so that the resulting dose-concentration curve becomes exponential. Drug disposition might also be very different from one patient to another depending on kidney and/or hepatic function and genetically determined metabolic pathways.

Adverse cardiovascular effects of anti-arrhythmia drugs. Part I: Proarrhythmic effects

Antiarrhythmic drugs are able to save patients from emergency dysrhythmic situations or to avoid symptomatic disorders when used in a prophylactic goal. However they can also induce adverse effects. Cardiovascular adverse effects, and especially proarrhythmic effects, are the most dreaded. Analysis of the underlying mechanisms of the onset and perpetuation of sustained arrhythmias could lead to a better understanding of causes of proarrhythmic effects and thus to a limitation of their occurrence. Antiarrhythmic drugs can modulate the three principal factors which are involved in the onset of arrhythmias: individual predisposing factors, trigger mechanisms and environmental factors. This multiparameter modulation will conduct either to suppress the arrhythmic disorders (antiarrhythmic effect) or to impair it (proarrhythmic effect). According to the numerous factors which take part in the onset and perpetuation of arrhythmia, incidence of proarrhythmic effect of antiarrhythmic drugs is very difficult to evaluate.

[Unwanted cardiovascular effects of anti-arrhythmia agents]

Antiarrhythmic drugs can cause many undesirable side effects affecting a number of organs and functions. Of those which affect the cardiovascular system, the proarrhythmic and negative inotropic effects are the most serious. Proarrhythmic effects, suggested by an aggravation of an arrhythmia or the induction of a previously undocumented arrhythmia, may be favorised by the presence of an arrhythmogenic substrate (unidirectional lock, delayed conduction, dual conduction pathways, low thresholds of depolarisation or fibrillation, presence of zones of hyperautomaticity...), "triggering" mechanisms (extrasystoles, variations of heart rate, after-depolarisation) and by changes in the cardiac environment (variations of autonomic nervous tone and hormonal changes, electrolytic or metabolic disorders...). An antiarrhythmic may have a beneficial action on one of these factors (for example, suppression of extrasystoles) but an aggravating effect on others (for example, an increase in the heart rate, creation of zones of reentry). This probably explains the fact that, for the moment, only molecules which have multifactorial modes of action have been shown to be beneficial in arrhythmias after myocardial infarction. Negative inotropic effects may be directly responsible for a deterioration in the hemodynamic status of patients on antiarrhythmics and indirectly responsible for aggravating arrhythmia by altering the anatomical substrate, so favorising proarrhythmic effects. The negative inotropic action may be related to ionic mechanisms (lowering intracellular calcium concentration due to blockade of the sodium channel by Class I antiarrhythmics) or to indirect mechanisms (reduced sympathetic tone, non-specific beta inhibition, calcium channel blockade, decreased left ventricular compliance, vasoconstrictor effects...).(ABSTRACT TRUNCATED AT 250 WORDS)