We describe the clinical evaluation of the nervous-system effects of solvent exposure. We review the current evidence in the epidemiological literature on neurotoxicological effects of solvents, and outline methods and issues to be taken into account in assessment of the patient whose symptoms may be related to solvent toxicity. Primary prevention of these disorders is essential, because treatment options are limited.

Pesticide exposures cause disorders varying from straightforward topical irritant reactions, such as those to synthetic pyrethroid insecticides, to complex systemic illness, such as that resulting from cholinesterase inhibition by organophosphate pesticides. The acute illness syndromes associated with pesticides most commonly encountered by clinicians are illustrated here by cases reported to the California Pesticide Illness Surveillance Program. The issues raised include asthma associated with exposure to contaminants in organophosphate insecticides, systemic toxicity of ingested pyrethroids (in children), and illnesses associated with spills or misuse of fumigants.

The two commonest forms of occupational skin disease are irritant and allergic contact dermatitis. Morphology and history are used to establish the diagnosis and the relation of the disorder to work exposure, respectively. Diagnostic patch tests are used to define further the diagnosis and aetiology of the dermatitis.

Only incomplete data are available to guide decision on anti-HIV treatment. A British HIV Association consensus is that guidance must draw on other evidence besides the randomised trial. Marker studies, work on disease pathogenesis and viral dynamics, and expanding knowledge of resistance patterns mean that the approach to therapy is constantly evolving. There is a need for well-informed dialogue between HIV-infected patient and physician to achieve rational, individualized treatment. However, the following broad principles have a wide consensus amongst HIV-treating physicians in the UK: (1) treatment should be offered before substantial immunodeficiency ensues; (2) initial treatment should include combinations of at least two drugs; (3) switches in therapy should involve substitution or addition of at least two new agents; (4) viral load and CD4 measurements are essential; (5) reduction in viral load to below the detection level of a sensitive assay represents the optimal treatment response and failure to achieve or sustain this control should prompt consideration of therapy modification. This response seems to be achieved most reliably with combinations of two nucleoside analogues plus a third agent (a protease inhibitor, a non-nucleoside reverse-transcriptase inhibitor, or a third nucleoside analogue) or of two protease inhibitors.

Sick-building syndrome (SBS) is an increasingly common problem. Although objective physiological abnormalities are not generally found and permanent sequelae are rare, the symptoms of SBS can be uncomfortable, even disabling, and whole workplaces can be rendered non-functional. In assessment of patients with SBS complaints, specific building-related illnesses suggested by history or physical examination should be ruled out. On-site assessment of buildings is extremely useful. Treatment involves both the patient and the building. Whenever possible, changes such as ventilation improvements and reduction of sources of environmental contamination should be initiated even if specific aetiological agents have not been identified.

Repetitive strain injuries (RSI) present an increasingly common challenge to clinicians. They consist of variety of musculoskeletal disorders, generally related to tendons, muscles, or joints, as well as some common peripheral-nerve-entrapment and vascular syndromes. These disorders generally affect the back, neck, and upper limbs, although lower limbs may also be involved. Although RSI may occur as a result of sports and recreational activities, occupational RSIs, affecting the patient's livelihood, are particularly important. These injuries result from repetitive and forceful motions, awkward postures, and other work-related conditions and ergonomic hazards. Occupationally induced RSIs are generally costly, creating a strong incentive for physicians to become familiar with the symptoms, signs, and risk factors so that they can be diagnosed early and appropriate interventions facilitated.

A possible solution to the chronic shortage of allografts is xenotransplantation, the use of tissue from an animal donor. Most experts believe that the pig will provide the most suitable solid organs for use in human beings. Although porcine organs are rapidly rejected by a process called hyperacute rejection (HAR), there is hope that several novel therapeutic strategies, already tested in animal models, will overcome this hurdle in patients. Successful clinical trials of these strategies, expected within the next few years, may herald the era of clinical xenotransplantation. However, there is increasing evidence that other barriers, both immune and non-immune, might exist to limit the survival of xenografts beyond the HAR phase. New strategies to overcome these barriers will be needed if long-term xenograft survival equivalent to, or better than, that of allografts is ever to be achieved.

Predicted numbers vary widely but the most authoritative estimate is that about 6950 cases of BSE will occur in cattle in the UK during 1997-2001 if new infections via feed have ceased as expected and if 10% maternal transmission occurs in the last half-year of the maternal incubation period. This assumes no culling or premature slaughter. Agreed cull strategies would reduce these numbers considerably and accelerate the observed rate of decline of the disease, but there is no scientific necessity for any cull. Bovine products that were banned as specified bovine offals in 1989/90 and as specified bovine materials by successive legislation are now excluded from the food and feed chains. As this second of the two-part article on BSE shows, there has been slippage in some of our control measures, but public and animal health are adequately protected if the legislation that has been evolved is enforced along present lines. Meanwhile, for human beings, bovine milk is safe to drink and beef is safe to eat.