EMC - Toxicologie-Pathologie最新文献

The common attitude towards disabled persons tends to be either the refusal of otherness or its acceptance. For thirty years, as written in the Law, solidarity is a duty that consists, for example, in the social integration by the work. In this context, the employment of handicapped workers has become an obligation. A complex series of either constraining or incentive measures has been implemented, to 'equalize opportunities'. Considering disability as a pool of three notions – deficiency, incapacity and disadvantage – has markedly contributed to the understanding of the concept. Such terminology should however be replaced by more positive words: efficiency, capacity for work, social participation. Although all medical fields play a role in favouring this participation, three types of practitioners are more specifically involved in the employment of disabled persons: the physician of the technical commission for vocational guidance and insertion for the assessment of work incapacity; the physician of the social insurance system, and the Occupational Medicine physician for the evaluation of the worker's ability to fulfil the post requirements. Such evaluation is both medical and social since it has to deal with various forms of social discrimination.

The main mission of the ten French Poison Centres is to provide, by telephone, toxicological information to both the public and health professionals. This activity is performed 24/24h by trained practitioners; it reduces health costs by limiting the number of consultations in emergency units. In these centres, other missions are also achieved: education of the population and accidents prevention, toxicological valuation, toxicovigilance, instruction and research in clinical toxicology, and participation to other vigilances systems like pharmacovigilance or centres for assessment and information about Pharmacodependency. The missions of the Poison Centres in France are specified in the executive order 96 – 833, 17^th September 1996.

The mining of lead-containing ores began in antiquity; this metal has more uses than any other one. The toxic effects of lead have also been described very early in history, and lead poisoning remains a problem in most countries: occupational exposure is frequent; children poisoning from paint chips or dust is pandemic in some developed countries including France and the USA; in areas where poorly mineralised drinking-water is distributed, lead can leach from water pipes and solder… This paper describes the poisonings due to inorganic and organic lead compounds: mains sources of these substances and circumstances of poisoning, toxicokinetics and toxic effects of lead including carcinogenicity, reproductive and developmental effects, organisation of the screening, diagnosis and medical management of lead poisoning in young children, and the principles of medical surveillance of occupational lead exposure.

Hypersensitivity pneumonitis has been extensively described in the past. However, recent reports have progressively modified our previous approach to the disease. These acquisitions especially concern: the increase in new etiological circumstances, especially occupational, and in new antigens; the key role of exposure factors and environmental cofactors which may mainly govern the development and outcome of the disease; the importance of bronchial obstruction and even emphysema as a long-term sequelae; for diagnosis, the major contribution of chest high-resolution CT scan which often shows characteristic images; finally, for treatment and prognosis, the possibility for patients, especially farmers, to carry on their occupation with some precautions.

Epidemiological studies performed in the last thirty years, either population-based or carried out on workplaces, show that a significant number of chronic obstructive pulmonary diseases (COPD) are work-related. Occupational fields in which a causal relationship is clearly established are mining industry, textile industry, processing of grain, pig and dairy farming. Since 1988, several regulations have been settled in France, allowing compensation for some cases of occupational COPD. However the medical criteria allowing compensation are very restrictive and a lot of occupational aetiologies are not listed as occupational diseases.

The phthalate esters (phthalates) represent a class of chemicals largely used, mainly as plasticisers for polyvinyl chloride in a wide range of domestic and industrial applications. Their volatility and water solubility are very limited. This paper focuses on the six most largely used phthalates. In rodents, the main toxic effects observed pertain to the liver and include hepatic tumours for di-isononyl phthalate and di-(2-ethylhexyl) phthalate. However, it is generally admitted that these effects are not relevant to humans, due to the mechanism of action of these compounds. The reproductive and developmental effects are considered to be the critical endpoints for some phthalates. Di-n-butyl phthalate, butylbenzyl phthalate, and di-(2-ethylhexyl) phthalate can produce alterations of the developing and adult male reproductive system, and an embryo/foetal toxicity. Information on their toxic effects in human is rare.

Endocrine disrupters (ED), which are substances likely to modify the functioning of a part of the endocrine system, constitute a current issue that remains widely studied in various fields. However, very few specific studies have been carried out to identify the relationship between occupational exposure and possible endocrine effects in exposed workers since these effects are difficult to study in the occupational field. This is due, in particular, to the multiple exposures and effect markers which are not easy to use in daily practice. Research has been mainly performed in the agricultural sector (with the handling of pesticides) and in the pharmaceutical industry in order to identify potential ED effects in employees. Among chemicals and families of chemicals, studies showing a possible effect of ED have been carried out mainly on pesticides, metals, solvents, and even xenoestrogens, with however no mechanism of action being clearly determined.

Solvents are widespread in use and, due to their lipophilic properties, they can interfere with nerve cell function. This explains why they are the main compounds involved in chronic toxic encephalopathy. Whereas acute effects are clearly accepted in the scientific community, there has been some debate on their chronic toxicity. In the 70s, the first studies were published on chronic toxic encephalopathy (CTE) in Scandinavia. In the 80s, an international classification defined four stages of the disease, from organic affective syndrome to dementia. One difficulty in diagnosis is the lack of specificity and the lack of knowledge on the mechanisms involved, particularly the nature of solvents, the doses and the duration of exposure. The syndrome is characterized by mood changes, followed by memory and attention impairment, difficulty in concentration and learning capacity, and in a final stage by generalized deterioration of cortical function. Advanced stages of chronic toxic encephalopathy have a poor prognosis with limited reversibility at best.

Aromatic amines are aromatic hydrocarbons in which at least one hydrogen of the cycle has been replaced by an amine substitute. They are gathered in the same chemical family but their toxicity differs from a compound to the other. Aromatic amines are used in many industries. The general population also can be exposed, from tobacco use or from alimentation. Contamination may be cutaneous, respiratory and digestive. Acute toxic effects can be methemoglobinemia (aniline), hemolytic anaemia, hepatitis (MDA), rhabdomyolysis with renal insufficiency, cardiomyopathy or ocular effects. Chronic effects include irritation, respiratory or cutaneous sensitizing (paraphenylene diamine). Many aromatic amines are known to be human carcinogenic agents (benzidine, 2-naphtylamine). Occupational bladder cancer is the most frequent of the cancers induced by aromatic amines. The industrial use of such carcinogenic aromatic amines is strongly regulated; this regulation includes the ban of the most carcinogenic ones, programs of medical surveillance for occupationally exposed workers.

Asbestos has been widely used in numerous industrial fields, both for its very good technical properties and its low cost. It has been banned in France since January 1997 but materials containing asbestos have not been removed everywhere and asbestos fibres inhalation is still current. Three categories of activities responsible for asbestos exposure have been identified: manufacturing asbestos or materials containing asbestos, removal or enclosure of materials containing asbestos, and all other activities likely to induce asbestos exposure. For each of these situations, a clear and precise regulation, specific preventive rules, and medical follow-up have been established. Compensation arrangements have been set up to indemnify victims of damage.