Occupational Exposure to Chromium of Assembly Workers in Aviation Industries

Aircraft are constructed by modules that are covered by a "primer" layer, which can often contain hexavalent chromium [Cr(VI)], known carcinogen to humans. While the occupational exposure to Cr(VI) during aircraft painting is ascertained, the exposure assessment of assembly workers (assemblers) requires investigations. Three biological monitoring campaigns (BM-I,II,III) were performed in an aviation industry, on homogeneous groups of assemblers (N = 43) and controls (N = 23), by measuring chromium concentrations in end-shift urine collected at the end of the working week and the chromium concentration difference between end- and before-shift urines. BM-I was conducted on full-time workers, BM-II was performed on workers after a 3-4 day absence from work, BM-III on workers using ecoprimers with lower Cr(VI) content. Samples were analyzed by atomic absorption spectroscopy and mean values were compared by T-test. Even if Cr concentrations measured during BM-I were lower than Biological Exposure Indices by ACGIH, statistically significant differences were found between urinary Cr concentrations of workers and controls. Despite 3-4 days of absence from work, urinary chromium concentrations measured during BM-II were still higher than references from nonoccupationally exposed populations. In the BM-III campaign, the obtained preliminary results suggested the efficacy of using ecoprimers. The healthcare of workers exposed to carcinogenic agents follows the principle of limiting the exposure to "the minimum technically possible". The obtained results evidence that assemblers of aviation industries, whose task does not involve the direct use of primers containing Cr(VI), show an albeit slight occupational exposure to Cr(VI), that must be carefully taken into consideration in planning suitable prevention measures during risk assessment and management processes.

Evaluation by Environmental Monitoring of Pesticide Absorption in Farm Workers of 18 Italian Tomato Cultivations

Tomato cultivation farms of Southern Italy were investigated in order to evaluate the general working conditions and the levels of exposure of farm workers to pesticides, during the mixing/loading and the application of pesticides on fields. Information on working modalities, personal protective equipment, etc. was collected using a questionnaire. Inhaling and cutaneous exposure levels were measured, and the estimated pesticide total absorbed dose was compared with Admissible Daily Intakes (ADIs). Field treatments were mainly carried out by using sprayers with open cab tractors, and, in 57.9% of cases, the pesticide mixture was manually prepared by mixing pesticides in a pail, often without using gloves (59.5%). The estimated pesticides absorbed doses varied in the range 0.56–2630.31 mg (mean value, 46.9 mg), and 20% of the measured absorbed doses exceeded ADIs. The findings obtained in the 18 examined farms show a worrying situation, suggesting the investigation of many more farms, so that a statistically significant picture of tomato cultivations in Southern Italy could be formed. Besides, the planning of training courses aimed to increase workers consciousness about health risks and how they can be prevented is advisable.

[Functional changes in human peripheral neutrophils in workers with different exposure to noxious agents]

Free radicals have a role in interaction between occupational exposure to multiple agents and biological systems; peripheral neutrophils (PMNs) are a source of free radicals and other reactive oxygen species. PMN's activity was evaluated by chemiluminescence assays referring to different noxious agents exposure levels. Two office workers groups were recruited: first one was exposed to several agents, control group was composed by lower exposure workers. Intra and extracellular chemiluminescence evaluation was performed to obtain radical species information. Stimulated PMNs from exposed subjects respond to the stimuli less than unexposed, and can be suggested as chronic exposure markers to noxious agents.

[Production cycles and risk agents]

Agricultural working contexts are characterized by numerous and heterogeneous working activities, leading to a noteworthy variety of risks for workers' healthcare. Safety and health risks vary according to each specific working activity, following seasonal cycles and productive process's phases. In particular, here the attention has been focused on the main risks factors present in large farms for fruit crops production, greenhouses and silos. Preventive measures for risks management are indicated in relation to each working activity step. Together with injury risks, essentially due to work equipment and machinery, unfavourable microclimatic conditions and hazards related to the manual handling of loads are often present, as well as chemical and biological risk agents adopted during the sterilization, disinfection and fertilization of grounds, plants and storage places. The reported findings highlight the necessity of increasing the risk consciousness of agricultural operators in order to facilitate the adoption of indispensable preventive and protective measures.

Quantification of sirolimus and everolimus by immunoassay techniques: test specificity and cross-reactivity evaluation

The possible cross-reactivity of immunoassays with structurally-related drugs was investigated. Innofluor Certican (FPIA) calibrators were measured by using IMx Sirolimus assay (MEIA) and MEIA Sirolimus calibrators were analysed by using FPIA Certican assay. Drug concentrations were measured in 95 and 100 samples from renal transplanted patients (RTP) on sirolimus or everolimus treatment by using immunoassays and LC/ESI-MSMS. A high cross-reactivity was found both for MEIA and FPIA. High correlation degrees, confirmed by the Bland-Altman and the Eksborg tests, were found between drug concentrations measured in real samples by both immunoassays (r = 0.909 and r = 0.970, respectively). LC/ESI-MSMS analysis of samples containing sirolimus showed no positivity for everolimus. Similarly, samples from patients on treatment with everolimus resulted negative as far as regards sirolimus. MEIA and FPIA could be considered mutually reliable and accurate alternatives for the specific-drug immunoassay. It should be noticed that in patients switching from one drug to the other unreal overestimation of the blood levels of the current administered immunosuppressant can occur.

[Algorithm validation for pesticide exposure risk evaluation by environmental monitoring data]

The risk evaluation related to the occupational exposure to hazardous substances can be performed either by analytical data coming from environmental and/or biological monitoring or by using models and mathematical algorithms. Models are often considered economically more advantageous, nevertheless, in order to assure their reliability, they need to be validated by objective monitoring data. A predictive model for the evaluation of risks due to the exposure to pesticides in agriculture was elaborated, and, for model validations, 20 tomato farms were examined. For each farm, information necessary to the risk evaluation by using the elaborated algorithm were collected and, simultaneously, an environmental monitoring for the evaluation of inhaling and cutaneous exposure was carried out. The potential risk was estimated by comparing analytical data from environmental monitoring with respect to ADI (Admissible Daily Intake) values, for each investigated pesticide. Then, the accordance between the potential risk and the risk given by the elaborated model was evaluated and an agreement of 85.6% was found, showing a substantial reliability of the proposed model.

[Risk evaluation of contact with pesticides in Naples municipality gardeners]

Pesticide use still now is a remarkable risk for all cultivation operators, including farmers and flower-growing workers. Recently, pesticides use on ornamental plant has been demonstrated to be able to determine a risk extension to general population. Aim of the project was to elaborate and to apply a method for pesticides risk evaluation in ornamental plant cultivations, as to define workers exposure and its possible diffusion to not occupationally exposed populations. Main features of method will be sampling and analysis approach. The first will estimate air dispersion of pesticides in garden centre, skin and garment smarminess in nurserymen and leaf adhered amounts, in concomitance with treatment and periodically to estimate natural decay. The latter will characterize pesticides by means of different methods (liquid and gaseous chromatography, spectrophotometry and spectrometry). Final aim will also be to identify the most reliable analytic method, as concerns accuracy, sensitivity and specificity.

[Antiblastic drug exposure: statistical analysis of the data coming from environmental monitoring of a site devoted to drug production]

An environmental monitoring strategy was carried out for the determination of surface concentrations of cyclophosphamide (CP), ifosfamide (IF) and 5-fluorouracil (5-FU) in a drug preparation room of an oncology ward. Analytes were determined by wipe tests, liquid-liquid extraction with diatomaceous earths and GC/MSMS or HPLC/UV analysis. The analysed 249 samples showed concentrations of CP, IF and 5-FU varying in the ranges 0.020-18.83, 0.100-26.96, 0.740-208.9 microg/dm2, respectively. It is noteworthy that the 9.3% (CP), 18.6% (IF) and 76.3% (5-FU) of the investigated surfaces showed high contamination levels, with analytes amount higher than 0.5 microg/dm2 and a progressive contamination decrement going from workbenches, floor, hood planes and other examined surfaces (interphone, telephone etc.). A significant correlation (rhos = 0.303, p = 0.001) between the measured analyte concentration and the analyte handled amount was found only in the case of IF, and a diffuse contamination (traces of all the three analytes) was found on all investigated surfaces, even when analytes were not been used during the sampling days.

[Combustion generated nanoparticles: mutagenicity and chemical reactivity]

Nanoparticles of organic carbon (NOC) are formed in combustion of hydrocarbon-rich fuels and have been detected in vehicle exhausts, suggesting their presence in urban atmospheres. Epidemiological studies showed that some causal relationships exist between particle concentration in the air and a wide range of health effects, but no toxicological studies are reported on the potential health risk of particles smaller than 4 nm. The present study investigated the mutagenicity and the reactivity of NOC collected in water samples from the exhausts of diesel and gasoline engines. Mutagenicity was tested following the Ames Test, with and without metabolic activation. Reactivity was investigated by using a new approach aimed to identify electrophilic agents present in the sample material, which if introduced into the organism, could interact with nucleophilic sites of biological macromolecules (DNA and proteins), forming adducts. Given the large number of nucleophilc sites within biological macromolecules, the complexity of NOC, and the inexact knowledge of its chemical structure, this approach was simplified by examining in vitro interactions between NOC particles and model peptides through LCIMS analyses of incubation mixtures The results indicate a high reactivity and, in several cases, the mutagenicity of NOCs, thus calling for suitable biomarkers assess NOC exposure associated with vehicle emissions.

Mono- and diiodocyclophosphamide as possible internal standards for cyclophosphamide quantification: characterization by ion trap multi-stage mass spectrometry and effects of iodine-chlorine substitution on the fragmentation pattern

Hospital personnel involved in antineoplastic drug preparation and administration to patients are exposed to large amounts of these drugs. Labour legislation indicates the necessity of planning monitoring strategies aimed at prevention and/or reduction of drug exposure. Monitoring strategies consist of quantitative determinations of indicators, present in environmental and biological matrices. Among the antineoplastic drugs widely used, cyclophosphamide (CP) has been identified as a suitable indicator of potential exposure to mixtures of antineoplastic drugs. Many literature methods for quantitative analysis of CP involve either liquid (LC) or gas chromatography (GC) with mass spectrometry (MS), both of which require use of a suitable internal standard. The present work focuses on the synthesis of mono- and diiodocyclophosphamide (CPI and CPI(2)) to be used as internal standard. These compounds were analyzed by GC/EI-MS/MS and LC/ESI-MS(n) using ion trap mass spectrometry. The product ion mass spectra are interpreted in terms of proposed structures of fragment ions. Iodine-chlorine substitution resulted in a weakening of the carbon-halogen bond with a noteworthy influence on the ion fragmentation processes. The proposed suitability of CPI and CPI(2) as internal standards was based on similarities to CP as regards ionization and fragmentation processes. The results obtained suggest that CPI could be used as internal standard for CP quantification by LC/ESI-MS/MS, and CPI(2) for GC/EI-MS/MS analyses.

[Biologically effective dose biomarkers]

Biologically effective dose markers--DNA and protein adducts--are classified among exposure biomarkers, and are currently used to assess the biologically active fraction of xenobiotics, which is capable of interacting with cellular macromolecules at the target site. Macromolecular adducts should not only be considered as exposure indicators; indeed, their biological significance can also be extended to biomarkers of effect and of susceptibility. The achievement of such a goal needs research programs aimed both at studying molecular mechanisms related to each step along the continuum of events between exposure and disease, and at establishing quantitative relationships between exposure levels and adduct formation, between adducts and early biological effects, effects and cellular structural/functional modifications, leading to the development and eventual increase in incidence of specific diseases. Moreover, different factors must be considered during data evaluation, such as interindividual variability, the background levels of biomarkers in non occupationally exposed population, the gradually decreasing doses of genotoxic agents involved in occupational exposure, and confounding factors such as diet and smoking habits. Despite the large body of literature documenting DNA and protein adduct molecular dosimetry for many carcinogen exposures, many authors highlight the need for systematic interlaboratory comparison and collaboration by measuring the same biomarkers using different techniques and/or different biomarkers related to the same exposure levels. There is also general agreement about reducing costs, so that dosimetric analyses can become economically more advantageous and accessible in all cases where they prove to be useful in preventing health risks.

Determination of urinary S-phenylmercapturic acid by liquid chromatography-tandem mass spectrometry

Urinary S-phenylmercapturic acid (S-PMA) is considered a useful biomarker for the measurement of low levels of benzene exposure, related to occupational exposure, smoking habits or environmental pollution. S-PMA quantitative analysis requires highly sensitive and specific techniques and purification procedures, mainly based on liquid-liquid or solid-phase extraction, which result in time expensive analyses. A method was developed for the quantitative determination of S-PMA in urine by using a simple, reproducible and easily automatizable HPLC purification followed by LC/ESI-NI/MS2 analysis. In order to reduce the cost of the analysis, related to the use of expensive labeled standards, p-bromo-S-phenylmercapturic acid (p-Br-S-PMA) was synthesized, characterized and used as internal standard. The feasibility and efficacy of the proposed method were examined by constructing calibration curves in the range from 6.2 to 200 microg/l and data were analyzed in terms of linearity and statistical parameters. The detection limit, related to the purification of 1 ml urine sample is 5 microg/l. The method was applied to the analysis of 12 urine samples from smoker subjects non-occupationally exposed to benzene. S-PMA urinary levels ranged from 13.6 to >200 microg/l, suggesting a high influence of life style in the S-PMA excretion. The proposed analytical method is suitable for the biological monitoring of both smoker and non-smoker workers, occupationally exposed to benzene. By processing at least 2 ml of urine samples, the method appears to be also useful for the evaluation of benzene uptake due to the environmental pollution.

[Fumigation of soil and food: assessment of occupational exposure to methyl bromide]

Innovative procedures were developed for the biological monitoring of workers exposed to methyl bromide, through the determination of biomarkers of exposure, such as bromide in serum, and of biomarkers of the biologically effective dose, such as haemoglobin adducts. The effectiveness of the developed techniques for the biological monitoring was tested through the analysis of blood samples from workers employed in soil fumigation.

A novel approach for identification and measurement of hemoglobin adducts with 1,2,3,4-diepoxybutane by liquid chromatography/electrospray ionisation mass spectrometry and matrix-assisted laser desorption/ionisation tandem mass spectrometry

The structural characterisation of the adducts formed by in vitro interaction of hemoglobin (Hb) with 1,2,3,4-diepoxybutane (DEB), the most reactive 1,3-butadiene (BD) metabolite, was obtained by liquid chromatography/electrospray ionisation mass spectrometry (LC/ES-MS) analysis of modified tryptic peptides of human hemoglobin chains. The reactive sites of human hemoglobin towards DEB and its hydroxylated derivatives (trihydroxybutyl (THB)-derivatives) were identified through the characterisation of alkylated tryptic peptides by matrix-assisted laser desorption/ionisation tandem mass spectrometry (MALDI-MS/MS). Based on this characterisation, a procedure was set up to measure the Hb-adducts of THB-derivatives by isotope dilution mass spectrometry with the use of a deuterated peptide standard. The results obtained here could permit optimisation of molecular dosimetry of BD-adducts, and extension of the analysis to the biological monitoring of occupational exposure to butadiene.

Mass spectrometric identification of a candidate biomarker peptide from the in vitro interaction of epichlorohydrin with red blood cells

The reaction products of epichlorohydrin with human alpha- and beta- globins, obtained through in vitro incubation of these compounds and red blood cells, were determined by using reversed-phase high-performance liquid chromatography (RP-HPLC), electrospray ionization mass spectrometry and matrix-assisted laser desorption/ionization tandem mass spectrometry. The alpha-globin was much more reactive than the beta-globin. At low incubation ratios, approximating the order of magnitude of epichlorohydrin concentration as found in workplaces, the only modified peptide still detectable was the 62-90 belonging to the alpha-chain and carrying an incremental mass of 92 u on either His72 or His89. Given that the two peptides co-eluted in a single chromatographic peak during RP-HPLC separation, they could be chosen as suitable biomarkers for quantification in the setting up of a new methodology for the biological monitoring of persons occupationally exposed, replacing currently known procedures.

Determination of cyclophosphamide and ifosphamide in urine at trace levels by gas chromatography/tandem mass spectrometry

A specific and sensitive method based on gas chromatography/tandem mass spectrometry with on-column injection was developed to quantify simultaneously cyclophosphamide and ifosphamide in urine by using trophosphamide as an internal standard. The urine samples were extracted with diethyl ether and derivatization was performed with heptafluorobutyric anhydride. The detection limits of cyclophosphamide and ifosphamide in urine samples were 0.1 and 0.5 ng ml(-1), respectively, with a signal-to-noise ratio of 3 : 1. The sensitivity, the specificity and the low cost of the instrumentation involved make this method suitable for economical analysis on a large scale, such as for the biological monitoring of occupational exposure to cyclophosphamide and ifosphamide in production plants and in hospitals during their pharmacological use.

Topology of the calmodulin-melittin complex

The topology of the Ca2+-calmodulin-melittin ternary complex has been investigated by a combined strategy which integrates limited proteolysis and cross-linking experiments with mass spectrometric methodologies. The rationale behind the methods is that the interface regions of two interacting proteins are accessible to the solvent in the isolated molecules, whereas they become protected following the formation of the complex. Therefore, when limited proteolysis experiments are carried out on both the isolated proteins and the complex, differential peptide maps are obtained from which the interface regions can be inferred. Alternatively, cross-linking reactions performed under strictly controlled conditions lead to the identification of spatially closed amino acid residues in the complex. Mass spectrometry can be employed in both procedures for the definition of the cleavage sites and to identify covalently linked residues. Our results show that melittin interacts with calmodulin by adopting a parallel orientation, i.e. the N and C-terminal halves of the peptide are anchored to the amino and carboxy-terminal domains of the protein, respectively. This orientation is inverted with respect to all the peptide substrates examined so far. A model of the complex was designed and refined on the basis of the experimental results, supporting the above conclusions. This finding reveals a further dimension to the already remarkable capability of calmodulin in binding different protein substrates, providing this protein with the capability of regulating an even larger number of enzymes.

Amino acid sequence and molecular modelling of glycoprotein IIb-IIIa and fibronectin receptor iso-antagonists from Trimeresurus elegans venom

Low-molecular-mass Arg-Gly-Asp (RGD)-containing polypeptides were isolated from the venom of Trimeresurus elegans by a simple two-step procedure consisting of membrane filtration and reverse-phase HPLC. A combination of electrospray MS, fast-atom bombardment MS and Edman degradation allowed us to ascertain the presence in the venom of different isoforms and to determine their primary structures. The amino acid sequences resembled the structure of elegantin, the only disintegrin previously reported from the T. elegans venom [Williams, Rucinski, Holt and Niewiarowski (1990) Biochim. Biophys, Acta 1039, 81-89]. MS analyses indicated the occurrence of differential proteolytic processing at both the N-terminus and the C-termins of the polypeptide chains. The amino acid sequence alignment of the elegantin isoforms with known components of the disintegrin family demonstrated the complete conservation of the 12 cysteine residues involved in disulphide bridges. Molecular modelling of elegantins predicted an overall folding of these molecules quite similar to that reported for the kistrin solution structure. The newly identified polypeptide isoforms strongly inhibited ADP-induced aggregation in both human and canine platelet-rich plasma but showed a different species-dependent specificity. These molecules were also able to inhibit B16-BL6 murine melanoma cell adhesion to immobilized fibronectin. The comparison of the structures and biological activities of elegantin isoforms and kistrin allowed us to highlight some structural features that, in addition to the RGD locus might be involved in the interaction of these snake-venom polypeptides with the integrin receptors on the platelet and cell surface.

High-performance liquid chromatographic approach to the separation of antiviral and immunostimulant fractions in Neuramide

Neuramide, a tissue extract having antiviral action against influenza A virus and immunostimulant action, was analyzed by preparative size-exclusion high-performance liquid chromatography (HPLC) and a low-molecular-weight fraction responsible for the antiviral action was isolated after reversed-phase HPLC. Four fractions having immunostimulant activity were also isolated, as evidenced by their potentiating action in the human lymphocyte proliferation induced by phytohaemagglutinin.