Carmelo Abbate

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.

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.

Minor Cognitive Deficits and Mood States in HIV-1 Infected Men

The aim of this study is to evaluate cognitive deficits and the psychoemotional state of patients affected by HIV-1. The sample, composed of 30 male HIV-1 positive patients aged on average 35.59, was assessed using a psychodiagnostic protocol based on the Wechsler Adult Intelligence Scale—Revised (WAIS-R) and the Profile of Mood State (POMS) applied at the three phases of observation: baseline (T1), 6 months later (T2), and 18 months later (T3). The outcomes were compared using a non-parametric statistical technique in a multivariate context (NPC test). The results highlight significative differences in responses during the three different phases of observation (T1, T2, T3) showing, in particular, reduced cognitive performance at T3 with increased anxiety, depression, aggressiveness, asthenia, and cerebral confusion. It is thus suggested that in the study sample the condition of disease accelerates the decline of specific brain mechanisms, resulting in psychiatric disorders with reduced quality of social and working life.

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.

Depression and Behavioral Disorders in Chronic Viral Hepatitis

This study assesses behavioral disorders and depression in 50 patients with chronic viral hepatitis (32 patients with HBV and 18 patients with HCV). A psychodiagnostic protocol composed of the IBQ and the BDI was administered to the entire sample in two stages—at the time of recruitment (T1) and after 8 months, when patients were receiving pharmacological treatment (T2). The results showed a predominance of behavioral disorders and depression in patients with HCV compared to HBV patients, although all patients with chronic viral hepatitis, despite reduction in viral load, displayed reduced quality of working life and relationships.