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The Study Group on Occupational Exposure to Inhalation Anaesthetics of the Lombardy Association of Occupational Health and Industrial Hygiene prepared a document that was discussed during the Congress "Occupational Risks due to Inhalation Anaesthetics", held in Brescia, Italy, on May 12, 1992. The same document was then approved by the Directory Council of the Lombardy Association of Occupational Health and Industrial Hygiene. Data on environmental concentrations of Nitrous Oxide collected from 1989 to 1991 in 269 operating rooms of 47 hospitals in Lombardy are reported. The measured levels are considerably lower than those collected from the same Study Group from 1985 to 1987 in 111 operating rooms. The methodologies for exposure control are discussed, regarding both environmental and biological monitoring. These two techniques are complementary and can be used with standardized methods. The review of the literature on the early effects showed, even with some uncertainty at the current exposure levels, effects on liver and Central Nervous System. Still controversial are the data regarding the reproductive toxicity. Health surveillance programs have been organized in the last 5 years in 18 Lombardy hospitals and they indicate no cases of pathologies due to inhalation anesthetics on 1498 subjects. Operative proposals are suggested on the methodology and the frequency of environmental/biological monitoring and health surveillance. The "technical limit values" reported in the document from the Italian Ministry of Health are also discussed. Finally, research topics are suggested in order to assess the early effects of exposure.

A research was carried out on risk evaluation of workers with different tasks in operating theatre. The airborne concentrations were determined by an IR analyzer with two distinct sampling lines: the first was placed in surgical zone and the second one in anesthesiological zone. The anesthetists resulted more at risk than surgical team. Nevertheless when the evaluation was based on N2O urinary concentration and data were stratified according to task a prevalent inhalation absorption resulted for non medical staff (instrumentist and professional nurse). Our data concerning N2O ranged between 95-764 ppm indoor and between 3-92 mcg/l in the urines of exposed subjects.

Three subject with professional activity in operating theatre and with a diagnosis of chronic viral "C" hepatitis are considered. All cases (Two surgeons and an anesthetist) had been continuously exposed to low level of airborne anesthetic compounds (Nitrous oxide and halogenated compounds). According to possible, but not proved, synergic effects, two cases with a clinical picture of active chronic hepatitis were classified as unqualified to specific work. The third case, affected by a persistent chronic hepatitis, was admitted to operating activities only for four hours a week, i.e. only an operating session a week. Hepatitis B and C markers must be always monitored during the medical surveillance in exposed people of operating theatre.

Up to the early eighties, a variety of epidemiological studies suggest that chronic exposure to low doses of anesthetic gases, as occurs in operating rooms, is an occupational risk factor for spontaneous abortion and congenital defects. Numerous and more recent epidemiologic studies are reviewed; currently it is suggested that there is inadequate evidence to conclude that occupational exposure to anesthetic gases causes increased rates of spontaneous abortion or congenital anomalies. The improvement of environmental conditions, that has reduced airborne levels of anesthetic gases in operating rooms, has been critical in reducing the risk of abortion and congenital defects. In agreement with recent epidemiological reports, we believe that the health surveillance of exposed workers must include the study of pregnancy outcome.

The Authors study the caries phenomenon by using DMF index in a scholastic population that belong to Ussl of Gazzada (VA). The research shows the alignment of data with previous experiences on our and other territories.

The Authors study the prevalence of the caries in the first permanent molar teeth by using DMF6 and consider the possibility of using such parameter instead of DMFT in order to reduce the time of observation in future researches.

An occupational type exposure-test to toluene di-isocyanate (TDI) for the diagnosis of specific respiratory sensitization is proposed. The subjects were tested by exposure to a two-pot polyurethane varnish with and without TDI activator, using a paint-spraying system under standard and controlled conditions, so as not to exceed the threshold limit value of TDI. Forced expiratory volume per second and specific airway resistance (plethysmographic method) were measured before each exposure and during the following 24 h. 47 subjects with clinical symptoms of asthma were examined during their hospital care. For the purpose of this study they were divided into two groups: 42 workers exposed to TDI and 5 not exposed. The preliminary control test, using polyurethane varnish without TDI activator, was always negative and no significant changes in ventilatory parameters were recorded. The spray-painting test, with the same varnish and TDI activator, gave positive responses in 35 out of the 42 exposed workers and negative findings in the group not exposed. This method permits to formulate an accurate diagnosis of TDI respiratory sensitization in the majority of cases (83%). Immediate asthmatic reactions were frequently observed in the exposed subjects with high acetylcholine reactivity. Ten subjects showed a late bronchial reaction (3 h or more after TDI exposure).

The alterations of lactate dehydrogenase and its isoenzyme fractions, of glucose-6-phosphate dehydrogenase, and of glutamate dehydrogenase were studied in the kidneys of 12 guinea pigs poisoned with a daily dose of 120 mg/kg body weight of lead nitrate given by means of an oesophageal catheter, and in the kidneys of 12 guinea pigs made ischemic by partial constriction of the renal artery. The investigation was made on homogenates of kidney in toto and on homogenates of cortex and medulla separately. In the kidneys of lead-poisoned guinca pigs and in the kidneys with ischemia as a result of stenosis of the renal artery, similar metabolic alterations were observed. In both experimental situations a marked increase in type M isoenzymes of lactate dehydrogenase (LDH 4 and LDH 5 ), an increase in glucose-6-phosphate dehydrogenase up to values twice those found in normal kidneys, and a marked reduction in glutamate dehydrogenase activity were observed. The increase of glucose-6-phosphate dehydrogenase activity was only moderately prevalent in the cortical zone, and the other enzymes examined did not undergo alteration of their percentage distribution between cortex and medulla. These results are interpreted as indicating a metabolic adaptation of the kidney to a condition of tissue hypoxia, in both experimental situations.

Among various chemical agents present at the workplaces in the rubber industry, a particular attention was adressed to the Polycyclic Aromatic Hydrocarbons (PAH) contained in oil and carbon black, but some questions regarding level of exposure are also controversially discussed. The literature reports that PAH may have irritant effects; moreover some of these have been recognized as probably or possibly carcinogenic to human by the International Agency for Research on Cancer, the European Union, and other institutions. In Lombardy, a study aimed to evaluate the occupational exposure in Benzo[b]fluorantene the rubber forming industry was planned during last two years. The results of environmental air monitoring (the 16 most relevant, according to the American Environmental Protection Agency, EPA) and biological monitoring (urinary 1-hydroxypyrene excretion) show that PAH exposure in these workers is not higher than that observed in other study regarding low level and acceptable exposure.

This survey was carried out in the molding of plastics and rubbers, in the "Professional Cancer Prevention Project" sponsored by the Lombardy region with the objective of developing and implementing protocols for evaluating exposure to carcinogens through the biological monitoring. The realities of molding the thermoplastic polymer ABS, rubber, and thermosetting plastics containing formaldehyde were examined. The carcinogenic substances identified in these processes were: 1,3-butadiene, acrylonitrile and styrene in molding ABS, polycyclic aromatic hydrocarbons (PAH) in molding rubber, and formaldehyde in molding the thermosetting plastics. Only for some of these substances biological indicators are available. The limited exposure to airborne chemicals in molding ABS and the intrinsic characteristics of biological indicators available for 1-3 butadiene have determined the non applicability of biological monitoring to this situation. The absence of a biological indicator of exposure to formaldehyde has made this situation not investigable. Exposure in the rubber molding was studied in 19 subjects applying the determination not metabolized PAH in urine. The levels of these indicators were similar to those measured in other groups of subjects without occupational exposure to PAH, confirming a low airborne contamination in this workplace.

A review of the literature about specific bronchial provocation tests in occupational asthma was made. The Authors focus on some problems related to the methods of exposure; furthermore, in separate chapters the bissynosis and the relationship between specific and aspecific hyperresponsivity are dealt with. The Authors conclude that it is necessary a standardization of the methods for the reproducibility of the tests, and, as in aspecific hyperresponsivity, so also the specific responsivity may be quantified in dose-response curves.

17 workers in a thermometer factory exposed to mercury for periods ranging from 1 to 40 years all had high urine and blood mercury levels on undergoing electromyographic examination. All were clinically free from central and peripheral nervous symptoms. 88% had subclinical neuropathy, mainly distal and axonal. There was no correlation between severity of the neuropathy and blood and urine mercury levels or between severity of neuropathy and duration of exposure to mercury. The presence of a subclinical neuropathy in symptomless workers exposed to mercury is perhaps the most reliable index for the detection of the early toxic effects of mercury on the peripheral nerve fiber when it is probably still reversible.