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Biomedical subjects

F Gobba

Publications and source records attributed to F Gobba.

At least 19 recordsLinked to original sources
PubMed2001

Occupational exposure to trihalomethanes in indoor swimming pools.

The study evaluated occupational exposure to trihalomethanes (THMs) in indoor swimming pools. Thirty-two subjects, representing the whole workforce employed in the five public indoor swimming pools in the city of Modena (Northern Italy) were enrolled. Both environmental and biological monitoring of THMs exposure were performed. Environmental concentrations of THMs in different areas inside the swimming pools (at the poolside, in the reception area and in the engine-room) were measured as external exposure index, while individual exposure of swimming pool employees was estimated by THMs concentration in alveolar air. The levels of THMs observed in swimming pool water ranged from 17.8 to 70.8 microg/l; the mean levels of THMs in ambient air were 25.6+/-24.5 microg/m3 in the engine room, 26.1+/-24.3 microg/m3 in the reception area and 58.0+/-22.1 microg/m3 at the poolside. Among THMs, only chloroform and bromodichloromethane were always measured in ambient air, while dibromochloromethane was detected in ambient air rarely and bromoform only once. Biological monitoring results showed a THMs mean value of 20.9+/-15.6 microg/m3. Statistically significant differences were observed according to the main job activity: in pool attendants, THMs alveolar air were approximately double those observed in employees working in other areas of the swimming pools (25.1+/-16.5 microg/m3 vs. 14.8+/-12.3 microg/m3, P < 0.01). THMs in alveolar air samples were significantly correlated with THMs concentrations in ambient air (r = 0.57; P < 0.001). Indoor swimming pool employees are exposed to THMs at ambient air levels higher than the general population. The different environmental exposure inside the swimming pool can induce a different internal dose in exposed workers. The correlation found between ambient and alveolar air samples confirms that breath analysis is a good biological index of occupational exposure to these substances at low environmental levels.

Adult↗
PubMed2000

Evaluation of half-mask respirator protection in styrene-exposed workers.

OBJECTIVE: The protection afforded by respirators to styrene (St)-exposed workers varies considerably. Our objective was to study the effective 'in the field' reduction in St exposure obtained by negative-pressure half-mask respirators worn by a group of fiberglass-reinforced plastics (FRP) workers. Protection was evaluated by measuring the reduction in urinary St (StU) excretion. METHODS: Seven FRP workers not using respiratory protection devices were studied for a week. External exposure to St was evaluated by personal passive sampling, and the internal dose by StU measurement. Then workers were asked to use a half-mask respirator for a week for the entire morning half-shift, and St exposure and internal dose were re-assessed. RESULTS: Mean environmental levels of St during the morning half-shift were 230-280 mg/m3, i.e., about three times the current limit proposed by ACGIH; the difference among days was not significant. Using respirators was accompanied by a large inter-individual and also intra-individual variability: the estimated reduction of StU values ranged from 30% to 90% (mean 60%). Mean StU values increased by 50% from Monday to Friday, while environmental St concentrations remained steady. Furthermore, the proportion of workers exceeding the biological equivalent exposure limit (BEEL) was 14% on Monday, double (33%) on Thursday, and triple (43%) on Friday. These data suggest a decrease of protection during the week. CONCLUSIONS: The protection afforded by negative-pressure half-mask respirators varies widely, which stresses the need to assess the effective reduction of exposure whenever these devices are introduced for St-exposed workers. If respirators are to be re-used for several days, their performance must be evaluated during the last shift of use. Measurement of urinary excretion of unmodified St proved a useful tool for the evaluation of respirator effectiveness in exposed workers.

Air Pollutants, Occupational↗
PubMed2000

Evolution of color vision loss induced by occupational exposure to chemicals.

The evolution of occupationally induced color vision loss was studied in workers exposed to various chemicals. Exposure was evaluated by biological monitoring or personal air samplers, and color vision using the Lanthony D-15 desaturated panel (D-15 d). The effect of short-term interruption of exposure was studied in 39 Styrene (St) exposed workers: at a first examination a dose-related color vision loss was disclosed; a re-test performed after one month's interruption of exposure did not show any improvement of the effect. The evolution during longer periods was studied in another group of 30 St workers. Exposure and color vision were evaluated, then a follow-up was done 12 months later: the exposure was unmodified or slightly decreased in 20 subjects, and D-15 d outcomes remained unchanged, while St levels had increased and color vision loss progressed in the other 10. Similar results were obtained in 33 PCE exposed dry-cleaners: no change in color perception was observed in 14 workers whose exposure decreased, while in the other 19 a rise in PCE levels was followed by a significant color vision worsening. In 21 Hg exposed workers whose mean urinary excretion of Hg was threefold the BEI proposed by ACGIH, a dose-related impairment in color perception was observed. 12 months after a marked reduction of exposure, an almost complete recovery of the impairment was observed. Our data show that an increase in exposure can induce a worsening in color vision loss. A short interruption in exposure did not reduce the effect. A more prolonged reduction of dose reversed color vision loss in Hg exposed workers, while in solvent-exposed individuals the progression deserves further evaluation. D-15 d proved a useful test for studies on the evolution of color perception in workers exposed to eye-toxic chemicals.

Color Perception↗
PubMed2000

Color vision: a sensitive indicator of exposure to neurotoxins.

In the last 15 years an increasing number of studies have investigated color discrimination in workers exposed to various neurotoxins. Color vision was generally evaluated using the Lanthony D-15 desaturated panel (D-15 d), a test suited to identify mild acquired impairments, that can be easily performed at the workplace. In most studies, results were quantitatively expressed using the method of Bowman or that of Vingrys and King-Smith: the former is the most widely reported, while the latter gives information on the type of color defect. Applying D-15 d, or other color perception tests, impairment in color vision was observed among workers exposed to several solvents (styrene, perchloroethylene, toluene, n-hexane, and carbon disulfide), or to solvent mixtures, and also to metals like mercury. Chemical related color vision loss is a sub-clinical early effect, and in most studies proved dose-related. For styrene and perchloroethylene, and also for solvent mixtures, an impairment was observed at exposure levels lower than the current occupational limits, suggesting that these limits may be inadequate for a proper protection of visual function of workers.

Carbon Disulfide↗
PubMed1999

Genetic polymorphisms influence variability in benzene metabolism in humans.

The role of genetic polymorphism in modulating urinary excretion of two benzene metabolites, i.e. trans,trans-muconic acid (t,t-MA) and S-phenylmercapturic acid (PMA), has been investigated in 59 non-smoking city bus drivers, professionally exposed to benzene via vehicle exhausts. Exposure to benzene was determined by personal passive samplers (mean +/- SD = 82.2 +/- 25.6 micrograms/m3), while internal dose and metabolic rate were evaluated by measuring urinary excretion of unmodified benzene (mean +/- SD = 361 +/- 246 ng/l), t,t-MA (mean +/- SD = 602 +/- 625 micrograms/g creatinine), and PMA (mean +/- SD = 5.88 +/- 4.76 micrograms/g creatinine). Genetic polymorphism at six loci encoding cytochrome-P450-dependent monooxygenases (CYP2E1 and CYP2D6), glutathione-S-transferases (GSTT1, GSTP1 and GSTM1) and NAD(P)H:quinone oxidoreductase (NQOR) was determined by polymerase chain reaction-based methods. No evidence emerged for a possible role of CYP2E1, GSTM1 and GSTP1 polymorphisms in determining the wide differences observed in the rate of benzene biotransformation. Conversely, a significantly higher t,t-MA urinary excretion was found to be correlated to, GSTT1 null genotype, and a significantly lower PMA excretion was detected in the subjects lacking NQOR activity and in the CYP2D6 extensive-metabolizers. Many biological (i.e. age and body burden) or lifestyle factors (i.e. rural or urban residence, use of paints and solvents, medication, alcohol and coffee intake), also taken into account as potential confounders, did not influence the correlations found. These findings suggest that CYP2D6, GSTT1 and NQOR polymorphisms contribute in explaining the metabolic variability observed in our sample. Therefore, these polymorphisms should be regarded as potential risk factors for benzene-induced adverse health effects.

Acetylcysteine↗
PubMed1998

Reversible color vision loss in occupational exposure to metallic mercury.

Color vision was evaluated in twenty-one mercury exposed workers and referents matched for sex, age, tobacco smoking, and alcohol habits. The Lanthony 15 Hue desaturated panel (D-15 d) was applied. In the workers, mean urinary Hg (HgU) was 115+/-61.5 microg/g creatinine; in all but one the values exceeded the biological limit (BEI) proposed by the American Conference of Governmental Industrial Hygienists. A dose-related subclinical color vision impairment was observed in Hg-exposed workers compared to the referents. Just after the survey, working conditions were improved. Twelve months later the workers were reexamined. Mean HgU was 10.0 microg/g creatinine and in no subjects was the BEI exceeded. Color perception was significantly improved compared to the first examination and, furthermore, no differences were observed between exposed workers and referents. The results add evidence that the color vision loss observed during the first part of the study was related to Hg exposure and, moreover, show that this effect is reversible. These data indicate that metallic Hg can induce a reversible impairment in color perception. This suggests that color vision testing should be included in studies on the early effects of Hg. The possibility of applying the D-15 d as an early effect index in the biological monitoring of Hg exposed workers should also be entertained.

Adult↗
PubMed1998

Modification in serum concentrations of aminoterminal propeptide of type III procollagen in patients with previous transmural myocardial infarction.

The aim of our study was to evaluate the modification of serum concentration of aminoterminal propeptide of type III procollagen (PIIINP) in 70 patients with previous transmural myocardial infarction. In 38 patients (group 1 ) PIIINP levels increased at 6 and 12 months after infarction; in 32 patients (group 2) PIIINP increased at 6 months, returning to baseline at 12 months. At the same time we observed a significant left ventricular enlargement and worsening of the performance in group 1, whereas in group 2 an improvement was seen in left ventricular volumes and performance. In conclusion, rearrangement of collagen myocardial matrix plays an important role in left ventricular postinfarction modification. This process can be easily followed over time in a noninvasive manner by dosing serum PIIINP concentrations.

Aged↗
PubMed1997

The urinary excretion of solvents and gases for the biological monitoring of occupational exposure: a review.

'In the field' application of the measurement of urinary excretion of unmodified solvent for the biological monitoring of exposed workers has been investigated in many recent papers. The results obtained for several solvents are reviewed. The values of correlation coefficients (r) and regression lines obtained for benzene, toluene, xylene, styrene, n-hexane, cyclohexane, 2- and 3-methylpentane, methyl chloride, tetrachloroethylene, carbon tetrachloride, methyl chloroform, p-dichlorobenzene, nitrous oxide, halothane, isoflurane, enflurane, acetone, methyl ethyl ketone and methyl isobutyl ketone are presented. The correlations observed were generally good: r values range from 0.50-0.97, and the majority are between 0.84 and 0.90. The regression lines reported for the same solvent in different studies present some variability: this is possibly due to an inadequate control of factors influencing the relationship between external dose and absorption, such as differences in body burden, work load, individual characteristics, etc. These factors are discussed. As a whole, results reported in the literature show that measuring of urinary excretion of unmodified solvents provides a highly sensitive and specific exposure index, and can also be applied for the biological monitoring of occupational exposure to low levels of solvents or to solvent mixtures. Nevertheless, for an adequate assessment of biological limit values, further studies evaluating the reproducibility of regression lines are needed, given that the aspects influencing the correlation between external dose and urinary excretion are fully controlled. Another crucial aspect is the correlation with early effects: even though this has yet to be evaluated for several solvents, for others such as styrene and perchloroethylene a good correlation was obtained, further supporting the usefulness of the measurement of urinary excretion of solvent for the biological monitoring of occupational exposure.

Absorption↗
PubMed1997

Excretion of N-acetyl-S-(1-phenyl-2-hydroxyethyl)-cysteine and N-acetyl-S-(2-phenyl-2-hydroxyethyl)-cysteine in workers exposed to styrene.

Styrene (S) has been shown to be responsible for neurotoxic effects, including behavioural changes and neuroendocrine disturbances. The initial step of S metabolism is conversion to styrene 7,8-epoxide (SO), which is present in two enantiomeric forms [(R)(+)-SO and (S)(-)-SO]; this electrophilic intermediate is considered to be directly responsible for most toxic effects of S. The major urinary metabolites derived from the biotransformation of SO in man are mandelic acid (MA) and phenylglyoxylic acid (PGA). In rats an alternative pathway has been demonstrated, which involves the conjugation of SO to glutathione (GSH), leading to the excretion of two specific mercapturic acids, N-acetyl-S-(-(1-phenyl-2-hydroxyethyl)-cysteine [M1] and N-acetyl-S-(2-phenyl-2-hydroxy-ethyl)-cysteine [M2]; a close relationship has been found between exposure to S and urinary excretion of M1 and M2 in rats. As a consequence of the chiral nature of SO, both M1 and M2 consist of two diastereoisomers (M1-'R', M1-'S', M2-'R' and M2-'S'). Early reports have shown that the conversion of S to mercapturic acids is much lower in man (below 1% of the absorbed dose) than in rats (about 10%). We propose an analytical method for the determination of urinary M1 and M2 in man, which involves a urine clean-up by a chromatographic technique with a short reversed-phase pre-column; purified samples are then deacetylated with porcine acylase and deproteinized by centrifugal ultrafiltration. A derivatization is then performed with o-phthaldialdehyde and 2-mercaptoethanol and the fluorescent derivatives are separated on a reversed-phase analytical column. The mobile phase consists of acetate buffer and methanol mixed at variable proportions, the fluorescence detector is set at 330 nm (exc.) and 440 nm (em.). M1-'S' and M1-'R' are separated (retention times = 52.8 and 73.7 min, respectively) while the diastereoisomers of M2 coelute as a single peak at 70.5 min. The detection limit is about 7 micrograms/l, the coefficients of variation are below 7% and the error percentages are less than 6%. The method was applied to 25 urine samples from workers exposed to S: significant correlations were found between mercapturic acids and MA and PGA, the best correlation being between M2 and PGA (r = 0.79). Urine samples form unexposed subjects showed no detectable amounts of the analytes. A high stereoselectivity is shown by the enzymes involved in the metabolism of S to mercapturic acids: M1-'S', which derives from (S)-SO, is excreted in much higher amounts than M1-'R', which derives from (R)-SO.

Acetylcysteine↗
PubMed1997

Inter-individual variability of benzene metabolism to trans,trans-muconic acid and its implications in the biological monitoring of occupational exposure.

Unmodified benzene (UBz) and trans,trans-muconic acid (t,t-MA) were measured in urine samples collected at the end of the first half-shift in 80 bus drivers from a large city in Northern Italy. Mean UBz was 1155 ng/l (S.D. = 494), range 85-1980 ng/l; these values roughly correspond to 10-1000 micrograms/m3 of benzene in air. Mean t,t-MA was 297 micrograms/g creatinine; the range was large (20-1295 micrograms/g creatinine), and the distribution of values was bimodal. At further analysis of t,t-MA data, two subgroups of 59 and 18 subjects were identified (3 outliers were excluded): mean values of the index were 108 (S.D. = 65) and 916 (S.D. = 264) micrograms/g creatinine respectively, and the values within each subgroup were normally distributed. The mean ratio between t,t-MA and UBz in the subgroups were 0.15 and 0.85, respectively; the difference was significant. The first subgroup was defined as 'poor t,t-MA metabolizers', the other as 'efficient t,t-MA metabolizers'. No inter-subgroup differences were observed regarding the main characteristics (age, dietary and smoking habits, etc.). As the parent compound of t,t-MA, trans,trans-muconaldehyde is myelotoxic, and its production has been implicated in benzene-induced leukemia. 'efficient' t,t-MA metabolizers may be at higher risk of developing benzene toxicity. If confirmed in further studies, the inter-individual variability rate of metabolizing benzene to t,t-MA may introduce some limitations in the application of this metabolite as an exposure index of low benzene exposure. Nevertheless, the t,t-MA/UBz ratio may be an important index of susceptibility to benzene toxicity.

Adult↗
PubMed1997

[Changes in serum levels of N-terminal procollagen type III propeptide as an index of postinfarction ventricular remodeling].

The levels of aminoterminal propeptide of type III procollagen (PIIINP) can be used as an index of collagen breakdown. The aim of our study was to evaluate modifications in serum concentration of PIIINP (PIIINPs) in patients with a first episode of myocardial infarction. We examined 70 patients admitted at our Institution for acute myocardial infarction and 10 normal subjects. PIIINPs dosage was obtained by radioimmunoassay method utilizing a commercial available kit. All patients underwent three PIIINPs dosages: within 24 hours after admission, at 6 and 12 months after myocardial infarction. Control values were 0.4 +/- 0.1 U/ml. In 38 patients (Group I) PIIINPs levels increased at 6 and 12 months after infarction: 0.53 +/- 0.2, 0.75 +/- 0.2 and finally 0.76 +/- 0.1 U/ml. In the remaining 32 patients (Group II) PIIINPs values increased at 6 months and then returned to baseline at 12 months: 0.56 +/- 0.2, 0.75 +/- 0.1 and then 0.46 +/- 0.1 U/ml. The end-diastolic volume index did not change significantly in Group I (from 93.7 +/- 21 to 79.7 +/- 20 ml/m2) while it decreased after 12 months in Group II (from 88.9 +/- 13 to 58.6 +/- 11 ml/m2; confidence interval 95% from 2 to 55 ml/m2; p = 0.03). Similarly, there was no significant variation in end-systolic volume index (ESVI, from 39.7 +/- 11 to 36.9 +/- 11 ml/m2) and ejection fraction (from 60 +/- 10 to 59 +/- 15%) in Group I; while in Group II ESVI decreased significantly (from 33.6 +/- 13 to 20 +/- 5 ml/m2, confidence interval 95% from 3 to 24 ml/m2; p = 0.02) and ejection fraction improved (from 62 +/- 11 to 72 +/- 15%; confidence interval 95% from -20 to -1%; p = 0.04). In conclusion, patients with elevated levels of PIIINPs at 12 months did not improve ventricular function while patients with PIIINPs returning to baseline at 12 months had an improvement. Our results suggest an active participation of newly formed collagen in post-infarct ventricular remodeling. Therefore PIIINPs may be a marker of this process.

Collagen↗
PubMed1996

Color vision loss among styrene-exposed workers neurotoxicological threshold assessment.

Styrene represents nowadays one of the most used organic solvent. The current exposure limit proposed for this chemical differs significantly from country to country: the Threshold Limit Value-Time Weighted Average (TLV-TWA) proposed by the American Conference of Governmental Industrial Hygienists (ACGIH) is 50 ppm while the German, Finnish and Swedish occupational exposure limit is 20 ppm. Nevertheless, effects on the nervous system were recently reported in workers exposed at TWA styrene levels below the current TLV. Neuro-optic pathways have been shown to be particularly vulnerable to organic solvent exposure. Analysis and measurements of visual functions can provide important information on early neurotoxic effects. Previous studies support the hypothesis that styrene exposure can induce a dose-dependent color vision loss. The aim of this study is to assess a threshold level below which no detectable effect occurs for color vision. We applied a sub-application of the change point problem in two-phase regression considering one phase as a constant line. In accordance with this model the maximum-likelihood technique was used as a method to examine the dose- effect relationship between external styrene exposure and chromatic discrimination. The present article presents a joint analysis of data from two previously published studies, one carried out in Canada and the other in Italy. The age and seniority of the workers from both countries were remarkably similar, as were the process type, the chemicals used and the work-tasks of exposed subjects. The mathematical method presented here shows the existence of a statistically significant threshold. This finding shows that, in fiberglass-reinforced plastics industry, visual color impairment could be significantly detected above 4 ppm (upper limit of the confidence interval at 5% = 26 ppm). The exact clinical meaning of this effect, and also the progress of the impairment in exposed workers, is still to be assessed in further studies. The results of our study support the need of a reduction of the occupational limits for styrene in workplaces to values close to or lower than German, Finnish or Swedish exposure limits.

Adult↗
PubMed1995

Colour vision loss in workers exposed to elemental mercury vapour.

We evaluated colour vision in 33 workers exposed to elemental mercury (Hg) vapour and in 33 referents matched for sex, age, alcohol consumption and cigarette smoking. The results were expressed as colour confusion index (CCI). In the workers urinary excretion of Hg (HgU) ranged from 28 to 287 micrograms/g creatinine. Subclinical colour vision loss, mainly in the blue-yellow range, was observed in the workers. This effect was related to exposure, as indicated by the correlation between HgU and CCI (r = 0.488, P < 0.01). In the workers whose HgU exceeded 50 micrograms/g creatinine, mean CCI was significantly increased compared to the matched referents. The results suggest that exposure to elemental Hg inducing HgU values exceeding 50 micrograms/g creatinine can induce a dose-related colour vision loss.

Adult↗
PubMed1995

Peripheral neuropathy in styrene-exposed workers.

BACKGROUND: The toxicity of styrene on the peripheral nervous system is still debated. CASES: The paper presents two cases of peripheral sensorimotor neuropathy in styrene-exposed workers. Exposure, evaluated by biological monitoring, ranged between 100 and 150% of the current limits proposed by the American Conference of Governmental Industrial Hygienists (ACGIH). The subjects complained of leg weakness and numbness, cramps, and paresthesia. Electrophysiology revealed a moderate peripheral sensorimotor neuropathy of a demyelinating type. Color-vision testing showed a subclinical deficit. Common inherited and acquired causes of peripheral neuropathy and dyschromatopsia other than styrene were ruled out by personal history, medical examination, laboratory data, and chest X-ray. CONCLUSIONS: The results suggest that long-term occupational exposure to environmental levels of styrene that are equal, or slightly above, the ACGIH limits can induce a clinical form of peripheral neuropathy and a subclinical impairment of color vision. As a consequence, a careful reappraisal of the real preventive meaning of the current ACGIH occupational limit for styrene, at least on an individual basis, is needed.

Adult↗
PubMed1994

Perchloroethylene exposure can induce colour vision loss.

We evaluated colour vision in 35 dry-cleaners exposed to perchloroethylene (PCE) and in a paired number of controls matched for sex, age, alcohol consumption and cigarette smoking. A subclinical colour vision loss, mainly in the blue-yellow range, was present in dry-cleaners. This effect was related to PCE exposure levels, and appeared at environmental concentrations of the solvent well below the current exposure limits for exposed workers. The results suggest that PCE exposure, even at low environmental levels, can induce a dose-related impairment of colour vision.

Adult↗
PubMed1993

Urinary styrene in the biological monitoring of styrene exposure.

The urinary excretion of styrene represents a promising indicator of exposure to this solvent. Nevertheless extensive research under field conditions is scant. In this investigation 214 styrene-exposed workers from 10 fiberglass-reinforced plastics factories were studied. Environmental monitoring was performed by personal passive sampling. Blood styrene and the urinary excretion of styrene and its main metabolites, mandelic acid (MA) and phenylglyoxylic acid (PGA), were measured. The correlation coefficient between the time-weighted average of environmental styrene and the mean urinary excretion of styrene was 0.88 (0.91 after logarithmic transformation), compared with the 0.82 and 0.78 of the end-of-shift MA and PGA values, respectively. A high correlation (0.86) was also found between styrene in the blood and urine. The results, obtained under field conditions with a large group of exposed workers, confirm the usefulness of the urinary excretion of styrene as an exposure index for the biological monitoring of styrene exposure.

Adolescent↗