Concetto Giorgianni

Neurotoxicity induced by exposure to toluene

SummaryThe object of the present study was to evaluate, with the aid of electrophysiologic techniques, the alterations induced in the auditory nervous system by exposure to toluene in a group of rotogravure workers. From 300 workers who were apparently in good health but were professionally exposed to toluene, we selected a sample of 40 workers of normal hearing ability. They were examined with an adaptation test studied by the brainstem auditory evoked potential technique with 11 and 90 stimulus repetitions a second. The results were compared with those in a group of workers of the same age but not professionally exposed to solvents. Our study demonstrates that exposure to toluene is able to induce a statistically significant alteration in the electric responses with both 11 and 90 stimuli repetitions. This alteration can be explained as a toluene exposure-induced modification, of physiologic stimulus conduction mechanisms, even in the absence of any clinical sign of neuropathy. Furthermore, such a modification could be observed in the electric responses of the entire auditory system, from peripheral receptors to brainstem nuclei.

Affective Correlates of Occupational Exposure to Whole-Body Vibration

Background: Exposure to whole-body vibrations (WBV) represents a highly diffuse occupational risk. Some studies report that chronic exposure to WBV induces a significant increment in the modifications of the cognitive and emotional area. The aim of this study was to investigate the long-term effects of WBV exposure on the neuropsychic and behavioural system. Methods: The study population consisted of 137 male subjects, mean age 45.7 years, working as drivers of mechanical trolleys and occupationally exposed to WBV of a frequency below 2 m/s2. The Profile of Mood States was administered to all subjects in a maximum time of 10 min and in the same operative conditions. The results were compared with those of a homogeneous control group by means of an innovative statistical technique. Results: The results show a significant difference in the response to the neurobehavioural test. The exposed group showed, in fact, a higher score compared with the controls for all 6 factors. In particular, the scores for factors F (fatigue-inertia), D (depression-dejection) and T (tension-anxiety) were more elevated, expressing a significant alteration of the psycho-affective status. Moreover, statistical analysis showed a correlation between exposure time and the score obtained for all factors in the exposed group. Conclusion: This study indicates that occupational exposure to WBV is associated with alterations of mood status and that these modifications are directly proportional to exposure time. Furthermore, our results show that psychological tests commonly used in psychopathologic diagnostics can be useful in monitoring alterations of psycho-emotional status determined by physical stressors.

Neurocognitive effects in welders exposed to aluminium

Objectives: Various authors who studied the effects of aluminium (Al) exposure on the neurocognitive system in the last 30 years have reached different and often contradictory conclusions. The aim of this study is to help clarify the effects that the metal causes on cognitive ability in a group of naval welders exposed to Al. Methods: The study was performed on a sample of 86 male Al welders in a shipyard in Messina. The average value of environmental Al, recorded in the workplace, was 19.5 mg/m3. The blood levels of Al, zinc, manganese, lead and chromium were monitored in all the subjects. The reagents used for the neuropsychic study were the Wechsler Memory Scale (WMS), the Colour Word Test or Stroop Test and the Test of Attention Matrixes. The results were compared with those obtained in a similar control group not exposed to Al and with an Al-b value of 6.93 g/l. Results: For all the mental reagents used, the reply is obtained in the sample of exposed subjects showed decreased cognitive response with regard to attention and memory performance. The comparison between the individual tests showed greater sensitivity of performance studied using the WMS and the Stroop Test compared with the Test of Attention Matrixes. The alterations encountered in the cognitive functions studied increased proportionally to time of exposure and quantity of metal absorbed. Conclusion: The study confirmed that occupational exposure to Al causes alteration in cognitive responses that are more evident in complex functions.

Neurotoxicity induced by lead levels: an electrophysiological study

The object of the present study was to evaluate, with the aid of visual evoked potentials (VEPs), modifications induced in the optic nerve by lead, and to investigate the relationship between blood lead levels (PbB) and modification of the VEP. We studied a sample of 300 men with PbB values between 17 and 60 μg/100 ml. Our study demonstrates that alterations in the latency of the VEP are dependent on PbB levels, though there is not a directly proportional relationship.

Neurobehavioral Evaluation in Humans Exposed to Hydrocarbons: A New Statistical Approach

Background: Epidemiological researches showed a significant increase in the alterations of the cognitive and emotional sphere in subjects exposed to hydrocarbons. This paper deals with a study carried out on a group of male workers between the ages of 35 and 40, who had been working as external workers in a large refinery. Methods: All the subjects worked in short shift rotation and were exposed to hydrocarbons during the loading of tank trucks. The response data reported by this investigation are compared to data of different male subjects who had also been working at the refinery for the same period of time, but as administrative day workers, and were certainly not exposed to the hydrocarbons. The nonparametric statistical analysis was carried out by a new nonparametric approach based on multivariate permutation tests. Results: Results show a significant difference in the response to neurobehavioral tests. The exposed group showed behavioral tendencies towards anxiety and depression that the nonexposed group did not. Conclusions: The study shows that occupational exposure to hydrocarbons is associated with neurobehavioral modifications, and that the use of psychometric tests can be useful for monitoring the psychosomatic consequences by exposure to hydrocarbon microdoses.

Changes Induced by Exposure of the Human Lung to Glass Fiber-Reinforced Plastic

The inhalation of glass dusts mixed in resin, generally known as glass fiber–reinforced plastic (GRP), represents a little-studied occupational hazard. The few studies performed have highlighted nonspecific lung disorders in animals and in humans. In the present study we evaluated the alteration of the respiratory system and the pathogenic mechanisms causing the changes in a group of working men employed in different GRP processing operations and exposed to production dusts. The study was conducted on a sample of 29 male subjects whose mean age was 37 years and mean length of service 11 years. All of the subjects were submitted to a clinical check-up, basic tests, and bronchoalveolar lavage (BAL); microscopic studies and biochemical analysis were performed on the BAL fluid. Tests of respiratory function showed a large number of obstructive syndromes; scanning electron microscopy highlighted qualitative and quantitative alterations of the alveolar macrophages; and transmission electron microscopy revealed the presence of electron-dense cytoplasmatic inclusions indicating intense and active phlogosis (external inflammation). Biochemical analyses highlighted an increase in protein content associated with alterations of the lung oxidant/antioxidant homeostasis. Inhalation of GRP, independent of environmental concentration, causes alterations of the cellular and humoral components of pulmonary interstitium; these alterations are identified microscopically as acute alveolitis.

Interleukin-10 involvement in exposure to low dose of benzene

Objective: To establish if serum levels of interleukin-10 (IL-10) in subjects exposed to benzene are connected with age, working years, and employment age. Methods: We evaluated serum levels of IL-10 in 51 employees working in oil refinery (group A) and in 16 office workers who resided in the same area (group B). Results: There was no statistically significant difference between serum concentrations of IL-10 in groups A and B. There was a statistically significant dependent relationship in group A between age, working years, and serum concentration of IL-10. There was a statistically significant and positive dependent relationship in group A between serum concentration of IL-10 and employment age. Conclusions: The role played by IL-10 in benzene immune suppression may be relevant and attention should be directed toward assessment of age, working years, and employment age in benzene-exposed populations.

Serum levels of copper, selenium and manganese in forestry workers testing IgG positive for Brucella, Borrelia, and Rickettsia

The aim of this study is to measure the alterations in the trace levels of serum copper (Cu), selenium (Se), and manganese (Mn) in forestry workers testing immunoglobulin G (IgG)-positive for Brucella, Borrelia, and Rickettsia. The study was conducted on a sample of 758 subjects (560 male and 198 female). All the subjects underwent medical examinations, which investigated particularly the presence of clinical signs compatible with zoonoses, and routine blood tests from venous blood sample, which tested previous immunisation versus cited microorganisms and serum concentration of Cu, Se, and Mn. The subjects were divided according to IgG positivity versus the cited microorganisms. The group of subjects with IgG positive versus Brucella showed statistically significant higher Cu levels than controls, while the Mn levels were not; the group of subjects with IgG positive versus Rickettsia showed higher levels of all three tested metals. The concentration of the examined metals did not show statistically significant difference between IgG-positive subjects versus subjects with Borrelia compared to controls. These data could confirm the role of both Cu and Se in the regulation of immune response.

Equilibrium disorders in workers exposed to mixed solvents

Background. Organic solvents cause diseases of the vestibular system. However, little is known regarding the correlation between vestibular damage and exposure to organic solvents below threshold limit values. The best measure by which to evaluate vestibular disorders is static and dynamic posturography. Objective. The aim of this study was to evaluate equilibrium disorders via static and dynamic posturography in workers without clear symptoms and exposed to low doses of mixed solvents. Methods. 200 subjects were selected. Using an Otometrics device (Madsen, Denmark), all subjects endured static and dynamic posturography testing with both eyes-open and eyes-closed conditions. Results were compared with a control group of unexposed individuals. Result. Based on the obtained data, the following results can be drawn: (a) subjects exposed to mixtures of solvents show highly significant differences regarding all static and dynamic posturography parameters in comparison to the control group; (b) posturography testing has proven to be a valid means by which to detect subliminal equilibrium disorders in subjects exposed to solvents. Conclusion. We can confirm that refinery workers exposed to mixtures of solvents can present subliminal equilibrium disorders. Early diagnosis of the latter is made possible by static and dynamic posturography.

Occupational exposure to anaesthetic gases and high-frequency audiometry

Objectives: Occupational exposure to anaestethic gases has been suggested to induce auditory damages. The aim of this study is to investigate high-frequency audiometric responses in subjects exposed to anaesthetic gases, in order to highlight the possible effects on auditory system. Methods: The study was performed on a sample of 30 medical specialists of Messina University Anaesthesia and Intensive care. We have used tonal audiometry as well as high-frequency one. We have compared the responses with those obtained in a similar control group not exposed to anaesthetic gases. Results were compared statistically. Results: Results show a strong correlation (p = 0.000) between left and right ear responses to all the audiometric tests. The exposed and the control group run though the standard audiometry analysis plays different audiometric responses up only to higher frequencies (2000 HZ p = 0.009 and 4000 Hz p = 0.04); in high-frequency audiometry, as all other frequencies, the attention is drew to the fact that the sample groups distinguish themselves in a significantly statistic way (10,000 Hz p = 0.025, 12,000 Hz p = 0.008, 14,000 Hz p = 0.026, 16,000 Hz p = 0.08). The highest values are the ones related to exposed subjects both in standard (2000 Hz p = 0.01, 4000 Hz p = 0.02) and in high-frequency audiometry (10,000 Hz p = 0.011, 12,000 Hz p = 0.004, 14,000 Hz p = 0.012, 16,000 Hz p = 0.004). Conclusion: Results, even if preliminary and referred to a low-range sample, show an involvement of the anatomic structure responsible for the perception of high-frequency audiometric responses in subjects exposed to anaesthetic gases.