Magnetic resonance imaging of the fetal brain.

INTRODUCTION: This review covers the recent literature on fetal brain magnetic resonance imaging, with emphasis on techniques, advances, common indications, and safety. METHODS: We conducted a search of MEDLINE for articles published after 2010. The search terms used were "(fetal OR foetal OR fetus OR foetus) AND (MR OR MRI OR [magnetic resonance]) AND (brain OR cerebral)". Consensus statements from major authorities were also included. As a result, 44 relevant articles were included and formed the basis of this review. RESULTS: One major challenge is fetal motion that is largely overcome by ultra-fast sequences. Currently, single-shot fast spin-echo T2-weighted imaging remains the mainstay for motion resistance and anatomical delineation. Recently, a snap-shot inversion recovery sequence has enabled robust T1-weighted images to be obtained, which is previously a challenge for standard gradient-echo acquisitions. Fetal diffusion-weighted imaging, diffusion tensor imaging, and magnetic resonance spectroscopy are also being developed. With multiplanar capabilities, superior contrast resolution and field of view, magnetic resonance imaging does not have the limitations of sonography, and can provide additional important information. Common indications include ventriculomegaly, callosum and posterior fossa abnormalities, and twin complications. There are safety concerns about magnetic resonance-induced heating and acoustic damage but current literature showed no conclusive evidence of deleterious fetal effects. The American College of Radiology guideline states that pregnant patients can be accepted to undergo magnetic resonance imaging at any stage of pregnancy if risk-benefit ratio to patients warrants that the study be performed. CONCLUSIONS: Magnetic resonance imaging of the fetal brain is a safe and powerful adjunct to sonography in prenatal diagnosis. It can provide additional information that aids clinical management, prognostication, and counselling.

LIMITING OCCUPATIONAL MEDICAL EVALUATIONS UNDER THE AMERICANS WITH DISABILITIES ACT AND THE GENETIC INFORMATION NONDISCRIMINATION ACT.

Although medical care delivery by one's personal physician is the paradigmatic American healthcare arrangement, in the workplace setting, many Americans undergo medical evaluations to assess their fitness for duty or degree of impairment. This Article explores the complex and evolving legal status of occupational medical evaluations. Beginning with the legal and ethical frameworks of occupational medical practice, the Article then examines the effects of increasingly detailed legal regulation under the Americans with Disabilities Act and the Genetic Information Nondiscrimination Act on employees, employers, and physicians.

Communication models in environmental health.

Communication models common in environmental health are not well represented in the literature on health communication. Risk communication is a systematic approach to conveying essential information about a specific environmental issue and a framework for thinking about community risk and the alternatives for dealing with it. Crisis communication is intended to provide essential information to people facing an emergency in order to mitigate its effects and to enable them to make appropriate decisions, and it is primarily used in emergency management. Corporate communication is intended to achieve a change in attitude or perception of an organization, and its role in environmental health is usually public relations or to rehabilitate a damaged reputation. Environmental health education is a more didactic approach to science education with respect to health and the environment. Social marketing uses conventional marketing methods to achieve a socially desirable purpose but is more heavily used in health promotion generally. Communication models and styles in environmental health are specialized to serve the needs of the field in communicating with the community. They are highly structured and executed in different ways but have in common a relative lack of emphasis on changing personal or lifestyle behavior compared with health promotion and public health in general and a tendency to emphasize content on specific environmental issues and decision frameworks for protecting oneself or the community through collective action.

Beginnings: The Occupational Health Program at the University of Alberta, 1984-1999.

The Occupational Health Program (OHP) at the University of Alberta played an important and pioneering role in the specialty of occupational medicine in Canada between 1984 and 1999. Its history illustrates the opportunities and obstacles in one of the smallest and most unusual medical specialties in Canada. After an auspicious beginning in 1984, with support from industry, labour, government, and the university, the OHP encountered, but overcame, many problems subsequently as a result of underfunding, organizational placement, and, after changes in leadership, interference from the provincial government department responsible for occupational health. The history of the OHP illustrates problems of small training programs and the unique problems of occupational medicine but also its potential as a model for medical training out of hospital that responds to population health as well as individual care.

The observatory: a model for studies in health, society, and the environment.

The concept of an observatory for examining and monitoring trends for research in the social sciences and health arose from analogy with the facilities of astronomy and the realization that close and consistent observation was essential to understand interactions among determinants of health in a community. Their theoretical foundations are largely grounded in the "population health model," an intellectual framework developed in 1974 and associated with a movement called "the new public health." We developed an observatory for an affluent, unexceptional, suburban jurisdiction ("County 20") in the province of Alberta, in western Canada, and used it to study and monitor both normative and emergent issues in environmental health. The observatory was conceived as a utility, or multi-purpose vehicle, for describing and responding to emerging community issues quickly and gathering data and qualitative findings as required. Case studies on issues of local importance allowed us to observe the dynamics of community response comprehensively, using quantitative and qualitative methods as appropriate. Valuable insights gleaned from the cases studied pertained to risk perception, the NIMBY syndrome, and reorganizing and auditing public health services. It did less well when the object of study was further removed from the community of interest, when there was no clear action item to be recommended, and when sponsors had expectations for certainty that could not be supported by available data sources. The observatory eventually was merged into a community health outreach program. The local observatory model is a practical, low-cost, and sustainable model for capturing generalizable and specifically local case study experience on a small scale but is limited in its effectiveness and by the scope of its coverage. It can be an initial step toward longitudinal and community monitoring studies on a larger scale. The observatory model can be used to elevate the level of case studies, impose rigor on analysis, and compile case studies for comparative and analytical studies.

Trading One Risk for Another: Consequences of the Unauthenticated Treatment and Prevention of Silicosis in Ontario Miners in the McIntyre Powder Aluminum Inhalation Program.

From 1943 to 1979, miners and factory workers in more than two hundred work sites globally were subjected to mandatory medical treatments by their employers as an unproven, and ultimately ineffective, treatment to prevent the lung disease silicosis. The treatments involved inhaling finely ground aluminum dust known as McIntyre Powder, blown into miners' change rooms each shift using compressed air systems. Tens of thousands of industrial laborers were exposed to McIntyre Powder, yet their story is scarcely known, and the possible health impacts of their aluminum treatments were rarely studied. This paper integrates the history of the aluminum prophylaxis program and its control by the northern Ontario mining industry with the lived experience of one of the affected miners, whose daughter created a voluntary registry which documents health issues in exposed miners, and stimulated research that found a link to her father's Parkinson disease.

Promoter mutation is a common variant in GJC2-associated Pelizaeus-Merzbacher-like disease.

Pelizaeus-Merzbacher-like disease (PMLD) is a clinically and genetically heterogeneous neurological disorder of cerebral hypomyelination. It is clinically characterised by early onset (usually infantile) nystagmus, impaired motor development, ataxia, choreoathetoid movements, dysarthria and progressive limb spasticity. We undertook autozygosity mapping studies in a large consanguineous family of Pakistani origin in which affected children had progressive lower limb spasticity and features of cerebral hypomyelination on MR brain imaging. SNP microarray and microsatellite marker analysis demonstrated linkage to chromosome 1q42.13-1q42.2. Direct sequencing of the gap junction protein gamma-2 gene, GJC2, identified a promoter region mutation (c.-167A>G) in the non-coding exon 1. The c.-167A>G promoter mutation was identified in a further 4 individuals from two families (who were also of Pakistani origin) with clinical and radiological features of PMLD in whom previous routine diagnostic screening of GJC2 had been reported as negative. A common haplotype was identified at the GJC2 locus in the three mutation-positive families, consistent with a common origin for the mutation and likely founder effect. This promoter mutation has only recently been reported in GJC2-PMLD but it has been postulated to affect the binding of the transcription factor SOX10 and appears to be a prevalent mutation, accounting for ~29% of reported patients with GJC2-PMLD. We propose that diagnostic screening of GJC2 should include sequence analysis of the non-coding exon 1, as well as the coding regions to avoid misdiagnosis or diagnostic delay in suspected PMLD.

The evolving spectrum of pulmonary disease in responders to the World Trade Center tragedy.

On September 11, 2001, events at the World Trade Center (WTC) exposed residents ofNew York City to WTC dust and products of combustion and pyrolysis. The majority ofWTC-exposed fire department rescue workers experienced a substantial decline in airflowover the first 12 months post-9/11, in addition to the normal age-related declinethat affected all responders, followed by a persistent plateau in pulmonary function inthe 6 years thereafter. The spectrum of the resulting pulmonary diseases consists ofchronic inflammation, characterized by airflow obstruction, and expressing itself indifferent ways in large and small airways. These conditions include irritant-inducedasthma, non-specific chronic bronchitis, aggravated pre-existing obstructive lung disease(asthma or COPD), and bronchiolitis. Conditions concomitant with airwaysobstruction, particularly chronic rhinosinusitis and upper airway disease, and gastroesophagealreflux, have been prominent in this population. Less common have beenreports of sarcoidosis or interstitial pulmonary fibrosis. Pulmonary fibrosis and bronchiolitisare generally characterized by long latency, relatively slow progression, and asilent period with respect to pulmonary function during its evolution. For these reasons,the incidence of these outcomes may be underestimated and may increase overtime. The spectrum of chronic obstructive airways disease is broad in this populationand may importantly include involvement at the bronchiolar level, manifested as smallairways disease. Protocols that go beyond conventional screening pulmonary functiontesting and imaging may be necessary to identify these diseases in order to understandthe underlying pathologic processes so that treatment can be most effective.

Panel 2: anticipatory risk assessment: identifying, assessing, and mitigating exposure risks before they occur.

Health threats place the military mission and deployed service members at risk. A commander's focus is on preventing acute health risks, such as diarrhea, because these quickly compromise the mission. However, in recent conflicts chronic and long-term illness risks have emerged as concerns. Department of Defense and Joint Chiefs of Staff mandates require documentation of exposures and environmental conditions to reconstruct exposures and evaluate future health risks. Current processes for identifying and assessing hazards, including identification and assessment before deployment and in time to take action to prevent or reduce exposures, when followed, are generally adequate for known hazards. Identifying and addressing novel, unexpected risks remain challenges. Armed conflicts are associated with rapidly changing conditions, making ongoing hazard identification and assessment difficult. Therefore, surveillance of the environment for hazards and surveillance of personnel for morbidity must be practiced at all times. Communication of risk information to decision makers is critical but problematic. Preventive Medicine (PM) personnel should take responsibility for communicating this information to non-PM military medical people and to military commanders. Communication of risks identified and lessons learned between PM personnel of different military units is extremely important when one military unit replaces another in a deployed environment.

Hydrogen sulfide: advances in understanding human toxicity.

Hydrogen sulfide is a relatively common, frequently lethal, and unique occupational hazard for which research since 1990 has uncovered many anomalies and subtleties and a previously unsuspected physiological role for the endogenous agent. The result has been uncertainty and misunderstanding, particularly for persons new to the literature. This review addresses evidence that settles past controversies, guides practical issues in evaluating human toxicity, addresses unresolved issues involving chronic exposure, and points the way to a deeper understanding of the agent and its effects.

The Fort McMurray Demonstration Project in Social Marketing: no demonstrable effect on already falling injury rates following intensive community and workplace intervention.

The Fort McMurray Demonstration Project in Social Marketing attempted to achieve mutually reinforcing effects from thematically coordinated educational and awareness efforts in the community as a whole and in the workplace and the inclusion of occupational safety within the framework of a community health promotion project. The study community was Fort McMurray, a small, industrial city in northern Alberta. The Mistahiai Health Region, several hundred kilometers to the west and also dominated by one city, Grande Prairie, served as the reference community. The intervention was based on media and events staged at public events, with supporting educational activities in schools and the community. It relied heavily on community-based partners and volunteers. Data on healthcare utilization of selected preventable injuries were obtained from Alberta Health for the time period 1990-1996 for the Regional Health Authorities of Northern Lights, where the only large population centre is Fort McMurray, and Mistahia. Age-adjusted aggregate injury rates were analyzed for evidence of an effect of the intervention. Severity was measured by proxy, using the number of diagnostic claims submitted for reimbursement for medical services in a given year. The communities differed in age-specific injury rates, with Fort McMurray showing higher rates for residents aged less than 55. Young adults and older adolescents showed higher levels of severity. Injury rates fell substantially and at similar rates in both communities over the five-year period. However, in both communities injury rates were already falling before the intervention in Fort McMurray began and continued to fall at about the same rate, slowing toward the end of the period. No evidence was found for an effect of the Project or for acceleration of the reduction in injury frequency in the intervention area. Over the period, fewer medical services were delivered in office settings and more in emergency rooms, in both communities. The Fort McMurray Demonstration Project in Social Marketing achieved an intensity of intervention and community participation that is unlikely to be sustainable in other communities. Despite this level of effort, the study did not achieve an unequivocal, demonstrable reduction in injury frequency above what was already occurring. This may have been due to a more powerful trend manifested as injury reduction across the province.

A century of the Archives of Environmental & Occupational Health.

With this issue, the Archives of Environmental & Occupational Health celebrates 100 years of continuous publication since its foundation as the Journal of Industrial Hygiene in 1919. During its first century, the Archives established an extraordinary legacy in the development of no less than three fields of research and practice: (1) occupational medicine, (2) industrial hygiene, and (3) air pollution studies and regulation. Its contribution to American environmental protection standards in air quality was particularly important, as the journal served as a major outlet for crucial air pollution research during the early years of the new United States Environmental Protection Agency. Its pages also chart the development of occupational health as an independent field, as well as the later emergence of modern environmental health as a related co-discipline. As the Archives moves into its second century of continuous publication, the journal will continue shaping the fields of environmental and occupational health; building on the solid foundation of evidence-based research from which humankind continues to benefit.

Communicating with healthcare providers.

Studies of risk communication have identified healthcare providers, especially physicians, as the source of information most trusted by the public on issues of environmental health. Nothing in medical, nursing or most healthcare provider training actually prepares practitioners to play this role and healthcare providers are generally more oriented toward treatment and medical care than prevention and public health. Healthcare providers require education in order to play this role but rarely seek it. Gaps in the knowledge of professional on the issue of Cryptosporidium illustrate the problem. For members of the professional water community, communicating with healthcare providers is best done when messages are delivered in familiar settings, such as hospital Grand Rounds (a universal format for teaching conferences) and provided in a narrative (case-based) form but gaining access is difficult if the topic is not obviously clinical in nature. In addition to being a critically important target group itself, public health professionals are easier to reach and may mediate good working relationships with medical practitioners. We suggest a strategy for water utilities based on partnerships with academic public health and providing education through well-recognized formats in continuing medical and nursing education.

DC Water and Sewer Authority and lead in drinking water: a case study in environmental health risk management.

In 2001, following a change in disinfection agent in anticipation of the Environment Protection Agency Disinfection Byproduct Rule, lead levels began rising in drinking water in Washington, District of Columbia, and in 2002, the DC Water and Sewer Authority was found to have exceeded the Environment Protection Agency lead action level, requiring compliance with a series of measures under the Lead and Copper Rule. In 2004, the issue became a public concern, drawing considerable media attention. The problem was eventually resolved through the application of orthophosphate but while it played out, the utility was forced to respond to a novel public health issue with few risk management options. This case study examines the lessons learned.

Elevated lead in drinking water in Washington, DC, 2003-2004: the public health response.

BACKGROUND: In 2003, residents of the District of Columbia (DC) experienced an abrupt rise in lead levels in drinking water, which followed a change in water-disinfection treatment in 2001 and which was attributed to consequent changes in water chemistry and corrosivity. OBJECTIVES: To evaluate the public health implications of the exceedance, the DC Department of Health expanded the scope of its monitoring programs for blood lead levels in children. METHODS: From 3 February 2004 to 31 July 2004, 6,834 DC residents were screened to determine their blood lead levels. RESULTS: Children from 6 months to 6 years of age constituted 2,342 of those tested; 65 had blood lead levels > 10 microg/dL (the "level of concern" defined by the Centers for Disease Control and Prevention), the highest with a level of 68 microg/dL. Investigation of their homes identified environmental sources of lead exposure other than tap water as the source, when the source was identified. Most of the children with elevated blood lead levels (n = 46; 70.8%) lived in homes without lead drinking-water service lines, which is the principal source of lead in drinking water in older cities. Although residents of houses with lead service lines had higher blood lead levels on average than those in houses that did not, this relationship is confounded. Older houses that retain lead service lines usually have not been rehabilitated and are more likely to be associated with other sources of exposure, particularly lead paint. None of 96 pregnant women tested showed blood lead levels > 10 microg/dL, but two nursing mothers had blood lead levels > 10 microg/dL. Among two data sets of 107 and 71 children for whom paired blood and water lead levels could be obtained, there was no correlation (r(2) = -0.03142 for the 107). CONCLUSIONS: The expanded screening program developed in response to increased lead levels in water uncovered the true dimensions of a continuing problem with sources of lead in homes, specifically lead paint. This study cannot be used to correlate lead in drinking water with blood lead levels directly because it is based on an ecologic rather than individualized exposure assessment; the protocol for measuring lead was based on regulatory requirements rather than estimating individual intake; numerous interventions were introduced to mitigate the effect; exposure from drinking water is confounded with other sources of lead in older houses; and the period of potential exposure was limited and variable.

Protecting children from toxic exposure: three strategies.

To a toxicologist, "poisonings" are cases in which the child has a defined pattern of symptoms, corresponding to toxic effects at a mid to high level of exposure. "Toxicity" refers to a broader spectrum of effects. At lower levels of toxicity a child may have no specific, individual symptoms but may be affected subclinically. There are three basic strategies to protect children: individual intervention, the preventive medicine strategy, and the public health strategy. This article uses lead exposure as a model for discussing these differences in terminology and the three different protective strategies.

Global pediatric environmental health.

Children are uniquely vulnerable to environmental health problems. Developed countries report as the most common problems ambient (outdoor) air pollution and lead. Developing countries have a wider range of common problems, including childhood injuries, indoor air pollution, infectious disease, and poor sanitation with unsafe water. Globally, the agencies of the United Nations act to protect children and perform essential reporting and standards-setting functions. Conditions vary greatly among countries and are not always better in developing countries. Protecting the health of children requires strengthening the public health and medical systems in every country, rather than a single global agenda.