Study of lung tissue from necropsy of a 58-year-old arc welder with arc welders' pneumoconiosis, confirmed by history, chest radiography, and pathology, demonstrates the versatility and usefulness of new techniques in scanning electron microscopy (SEM). Secondary electron imaging, the most familiar SEM mode, showed heavy cellular infiltrates in alveoli, the interstitium, and within the interstices of loose whorled fibrotic nodules. Backscattered electron imaging, in which contrast is proportional to elemental atomic number, revealed intracellular metal particles not otherwise visible. Microprobe analysis, energy-dispersive x-ray spectrometry, mapped elemeental iron over the particle image and identified traces of silicon in the whorled nodules. Arc welders' pneumoconiosis appears to be more than a benign siderosis resulting from particulate iron deposition. Simultaneous exposure to other components of welding fumes may alter the pathologic picture, inducing a more complicated fibrotic reaction. The more recently developed advanced techniques of SEM are well suited to the study of pneumoconioses and other problems of heterogenous tissue and mixed chemical systems.

Electron Probe Microanalysis↗

PubMedDate not supplied

Recall bias in exposed subjects following a toxic exposure incident.

Attempts to reconstruct health effects following toxic exposure incidents may be subject to bias from distorted or incomplete recollection. We examined recall in 22 of 31 subjects exposed to fumes from ruptured drums containing nitric acid during a U.S. Environmental Protection Agency-supervised hazardous waste site clean up operation in August 1983. Exposed subjects were interviewed by emergency room staff immediately after the episode and the next morning by telephone by a public health epidemiologist. Six months later, the subjects were again interviewed by telephone and asked to report the symptoms they had experienced during the incident. For each respondent, symptoms recalled at 6 mo were compared to symptoms reported at the time. We found a low level of agreement compared to that expected by chance, associated with significant nonrandom differences in the distribution of responses consistently favoring selective recall on the later interview. We conclude that allowing time to elapse before obtaining data on individual symptoms following exposure may lead to a significant bias in response.

Adolescent↗

PubMedDate not supplied

Fatal disseminated aspergillosis in a previously well young adult with cystic fibrosis.

Patients with cystic fibrosis (CF) are often colonized by Aspergillus species in their respiratory tract but rarely develop infection with this fungus. A young woman with CF who had mild pulmonary involvement and who was in good health developed a fulminant illness presenting as brainstem infarction and simulating thrombotic thrombocytopenic purpura. At necropsy she was found to have disseminated aspergillosis and a depletion of lymphocytes in the thymus-independent zone of splenic follicles. This unique case may be an unusual expression of abnormal T-cell function and the paradoxical histopathologic findings may relate to the disturbance in humoral immunity in children with CF recently described by Matthews et al.

Adult↗

PubMedDate not supplied

Proposed air quality objectives for fine particulate air pollution.

Explore the source record for details and available documents.

Air Pollution↗

PubMedDate not supplied

Learning objectives for training and continuing education in occupational medicine.

Occupational medicine (OM) training programs apparently vary more in content and practice skills than other medical special training programs. This variation appears to exist both within programs, in that individual trainees in some programs may engage in very different experiences, and between programs. Some variation is not necessarily undesirable, considering the multiplicity of professional roles, the eclectic backgrounds of many residents, and the diversity of points of view in each of the specialties. However, excessive variation in medical content and practice skills in the training experience may result in uneven training and, in fact, undermines the integrity of the specialty. A consensus on core content and skills for specialty training might help. A consensus would help physicians to judge their own level of preparation in order to decide to participate in further training and continuing education programs. I prepared a model set of objectives for occupational medicine under the auspices and with the endorsement of the American College of Preventive Medicine. Further evaluation can refine the objectives, implement use of the objectives in formal training programs, and assess the utility of the format for other preventive medicine specialties.

Clinical Competence↗

PubMedDate not supplied

Evaluation of scientific evidence in law, adjudication and policy: when occupational health takes the witness chair.

Health and medical knowledge are essential to the resolution of disputes in law and administrative applications (such as workers' compensation) and provide essential input into public policy decisions. There are no socially agreed-upon rules for the application of this knowledge except in the law. On a practical level, the legal system lacks the capacity to evaluate the validity of knowledge as evidence and therefore relies heavily on expert opinion. Over the last 30 years, an approach called "critical appraisal" and "evidence-based medicine" addressed a similar problem in medical practice and established norms for the acceptance of evidence in clinical medicine. A similar evidence-based framework may be possible for applying knowledge of health and medicine to dispute resolution in the law. One critical issue is how to apply scientific evidence when the standard is "more likely than not" rather than scientific certainty. Another is how the generalizations drawn from epidemiology and population-based sciences are interpreted and individualized, as they must be, for the case at hand. A related issue is how risk is interpreted for an individual after the fact, when conventional probability treats risk before the fact and conventional biostatistics applies primarily to a population. This emerging approach is called "evidence-based medical dispute resolution".

Canada↗