Biological monitoring of cobalt in hard metal factory workers.

PURPOSE: The main aim of this study was to investigate the cobalt (Co) concentrations in urine along 4 months and their relationship with Co concentrations in blood and haemoglobin (adducts) in 34 workers from a hard metal manufacturing plant where metallic Co and Co oxide were used. Furthermore, the excretion kinetics of Co was investigated and the half-lives of Co in blood, plasma and urine were calculated along 18 days of non-exposure in the same workers. METHODS: Co was analysed, in all biological samples, by ICP/MS. RESULTS: Wide fluctuations in the urinary Co concentration were observed throughout the work shift and during the work week. A highly significant linear correlation was found between Co concentration (geometrical mean) in urine samples provided each Thursday (end shift) during 16 subsequent weeks and levels of Co-haemoglobin adducts or blood Co concentrations at the end of the same period. The Co elimination kinetics in globin calculated along 18 days without Co exposure was slow, being related to the physiological metabolism of haemoglobin, while in blood, plasma and urine Co half-lives were 12.3, 9.1 and 5.3 days, respectively. CONCLUSION: Co concentrations in haemoglobin or blood are highly related to the geometrical mean concentration of urinary Co when samples are collected weekly for several subsequent weeks. The biological monitoring of occupational exposure to Co in hard metal facilities provides reliable results by using the Co concentrations in haemoglobin or in whole blood. The urinary findings, though, do not show the same reliability because of their wide daily and weekly fluctuations.

Citrate-stabilized lanthanide-doped nanoparticles: brain penetration and interaction with immune cells and neurons.

AIM: To unravel key aspects of the use of lanthanide-doped nanoparticles (NPs) in biomedicine, the interaction with immune and brain cells. MATERIALS & METHODS: Effects of citrate-stabilized CaF2 and SrF2: Yb, Er NPs (13-15 nm) on human dendritic cells and neurons were assessed in vitro. In vivo distribution was analyzed in mice at tissue and ultrastructural levels, and with glia immunophenotyping. RESULTS: The NPs did not elicit dendritic cell activation and were internalized by cultured neurons, without viability changes. After intravenous injection, NPs were found in the brain parenchyma, without features of glial neuroinflammatory response. CONCLUSION: Lanthanide-doped NPs do not activate cells protagonists of systemic and brain immune responses, are endocytosed by neurons and can cross an intact blood-brain barrier.

In vivo study on metal release from fixed orthodontic appliances and DNA damage in oral mucosa cells.

Interest in the amount of metal ion intake from dental alloys has grown. Fixed orthodontic appliances usually include brackets, bands, and archwires made of stainless steel, nickel-titanium, or nickel-cobalt alloys, and these can release metal ions. The purpose of this study was to investigate the biocompatibility in vivo of fixed orthodontic appliances, evaluating the presence of metal ions in oral mucosa cells, their cytotoxicity, and their possible genotoxic effects. Mucosa samples were collected by gentle brushing of the internal part of the right and left cheeks of 55 orthodontic patients and 30 control subjects who were not receiving orthodontic treatment. The cells were immediately prepared for cell viability and the comet assay. Nickel and cobalt cellular content was quantified by inductively coupled plasma mass spectrometry (ICP-MS). The results indicate that nickel and cobalt concentrations were 3.4-fold and 2.8-fold higher, respectively, in the patients than in the controls; cellular viability was significantly lower in the patients than in the controls, and there was a significant negative correlation with metal levels. The biologic effects, evaluated by alkaline comet assay, indicated that both metals induced DNA damage (more cells with comets and apoptotic cells). There were significant positive correlations between (1) cobalt levels and the number of comets and apoptotic cells, (2) nickel levels and number of comet cells, and (3) cobalt levels and comet tails. This study corroborates that nickel and cobalt released from fixed orthodontic appliances can induce DNA damage in oral mucosa cells.

Comparison of breath, blood and urine concentrations in the biomonitoring of environmental exposure to 1,3-butadiene, 2,5-dimethylfuran, and benzene.

OBJECTIVES: To investigate and compare alveolar, blood, and urine concentrations of 1,3-butadiene, 2,5 dimethylfuran, and benzene, in non-occupational exposure to these products. METHODS: Benzene, 2,5-dimethylfuran and 1,3-butadiene were measured in the breath, blood, and urine samples of 61 subjects living in small mountain villages. All 61 were regularly employed as forestry workers. Sampling was done during the long winter-season non-working period. Samples were collected after overnight rest and analysed by headspace and GC-mass spectrometry methods. RESULTS: The median 1,3-butadiene level was 1.2 ng/l (range: <0.8-13.2 ng/l) in alveolar air, 2.2 ng/l (range: <0.5-50.2 ng/l) in blood, and 1.1 ng/l (range: <1-8.9 ng/l) in urine. The median benzene level was 5.7 ng/l (range: <1-24.9 ng/l) in alveolar air, 62.3 ng/l (range: 33.5-487.2 ng/l) in blood, and 63.4 ng/l (range: 25.8-1099.1 ng/l) in urine. The median 2,5-dimethylfuran level was 0.5 ng/l (range: <1-12.5 ng/l) in alveolar air, 2.5 ng/l (range: <5-372.9 ng/l) in blood, and 51.8 ng/l (range: <5-524.9 ng/l) in urine. In several cases, 2,5-dimethylfuran levels were below the detection limit in alveolar air and blood, especially in non-smokers. 1,3-Butadiene, 2,5-dimethylfuran and benzene levels were significantly higher in smokers than non-smokers in all biological media. CONCLUSIONS: 1,3-Butadiene and benzene, as ubiquitous pollutants, are detectable and quantifiable in human alveolar air, blood and urine. 2,5-Dimethylfuran, which is not a usual environmental pollutant, is almost always detectable in biological media, but only in smokers.