Role of risk assessment in public health practice.
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Decision Support Techniques↗
Biomedical subjects
B L Johnson
Publications and source records attributed to B L Johnson.
Primary axillary-subclavian venous thrombosis: is aggressive surgical intervention justified?
Multimodal (thrombolysis, surgical decompression, venous reconstruction, oral anticoagulation) treatment of primary axillary-subclavian venous thrombosis was reviewed to assess the impact of venous patency on functional outcome. Since 1996, 7 patients (6 men, 1 woman) of ages 16-53 years (mean 33 years) presented with symptomatic acute axillosubclavian venous thrombosis as a result of a recent athletic or strenuous arm activity. Five patients had undergone previous (>2 weeks) catheter-directed thrombolysis and venous angioplasty. Diagnostic contrast venography followed by repeat catheter-directed thrombolysis demonstrated abnormal (residual stenosis [n=6] or occlusion [n=1]) axillosubclavian venous segments in all patients. Surgical intervention was performed at a mean interval of 7 days (range 1-19 days) after thrombolysis and consisted of thoracic outlet decompression with scalenectomy and 1st rib resection via a paraclavicular (n=4) or supraclavicular (n=3) approach. Medial claviculectomy or cervical rib resection was performed in 2 patients. Concomitant venous surgery was performed in all patients to restore normal venous patency by circumferential venolysis (n=7) and balloon catheter thrombectomy (n=3), or vein-patch angioplasty (n=2), or endovenectomy (n=5), or internal jugular transposition (n=2). Postoperative venous duplex testing beyond 1 month identified recurrent thrombosis in 4 patients despite therapeutic oral anticoagulation. Subsequent venous recanalization was documented in 3 patients. Poor functional outcome was associated with an occluded venous repair and extensive venous thrombosis on initial presentation. A patent or recanalized venous repair present in 6 of 7 patients was associated with good functional outcome and may justify multimodal intervention in patients with primary axillosubclavian effort thrombosis presenting with recurrent thrombosis and significant residual disease after thrombolysis.
Adolescent↗
The toxicologic hazard of superfund hazardous-waste sites.
Uncontrolled hazardous-waste sites are a major environmental and public health concern in the United States and elsewhere. The remediation of and public health responses to these sites is mandated by the federal Superfund statute. Approximately 40,000 uncontrolled waste sites have been reported to U.S. federal agencies. About 1,300 of these sites constitute the current National Priorities List (NPL) of sites for remediation. Findings from a national database on NPL sites show approximately 40% present completed exposure pathways, although this figure rose to 80% in 1996. Data from 1992 through 1996 indicate that 46% of sites are a hazard to public health. Thirty substances are found at 6% or more of sites with completed pathways. Eighteen of the substances are known human carcinogens or reasonably anticipated to be carcinogenic. Many of the 30 substances also possess systemic toxicity. The high percentage of sites with completed exposure pathways and the toxicity potential of substances in these pathways show that uncontrolled hazardous-waste sites are a major environmental threat to human health. Findings from the United States' experience in responding to uncontrolled waste sites are relevant to other countries as they address similar environmental and public health concerns.
Databases, Factual↗
A review of health-based comparative risk assessments in the United States.
Comparing the risks posed by specific environmental hazards has become attractive to policy makers and legislative bodies as an aid to budgeting and other policy decisions. This paper reviews the human health-based findings from the first federal comparative risk assessment project and subsequent reviews conducted by 15 states and local government agencies in the United States. Methods are described on conducting comparative risk assessments that include substantive involvement of the public and special interest organizations. A consolidation of the comparative risk assessments of 15 states revealed good agreement with federal health-based environmental hazard priorities and partial agreement with local-government health departments. In descending order of priority, indoor air pollutants (excluding radon), criteria air pollutants, hazardous air pollutants, indoor radon, lead contamination, inactive hazardous waste sites, and drinking water at the tap are the highest ranked environmental hazards to human health.
Air Pollutants↗
Hyperplastic persistent pupillary membrane--surgical management.
Two infants, aged three days and six weeks, respectively, presented with dense extensive persistent pupillary membranes as sporadic isolated findings. A clear central pupillary aperture was unable to be achieved with mydriatic agents. The patients were treated by surgical removal of the membranes at age five days and six months respectively. Surgery was without complication and visual development has been normal. We suggest that early intervention in the first weeks or months of life is necessary to prevent the development of amblyopia. If mydriasis is unsuccessful, surgery is recommended followed by optical correction and occlusion therapy as necessary.
Anterior Chamber↗
Congenital aphakia: a clinicopathologic report of three cases.
BACKGROUND: Congenital aphakia is a rare condition that has been classified as primary when no lens induction of the surface ectoderm occurs and secondary when lens development takes place but later is resorbed or expelled in utero. METHODS: The authors report the clinical and pathologic findings in three infants with congenital aphakia whose eyes were enucleated either at surgery at 11 months or at autopsy after 1 and 3 days of life. RESULTS: Two cases classified as primary congenital aphakia had severe microphthalmos, anterior segment aplasia, or anomalous development and posterior choroidal and optic disc colobomas. One was in a case believed to be Waardenburg's recessive anophthalmia syndrome and the other had 18 trisomy. A case of secondary congenital aphakia had findings of Peter's syndrome and features suggesting rubella, which had been observed in some previous reports. CONCLUSIONS: Primary congenital aphakia can result from a variety of teratogenic events in the first 4 weeks of embryogenesis and results in microphthalmos and severe anterior segment aplasia/dysplasia. Secondary congenital aphakia is associated with less severe ocular anomalies. The possible role of deletion or mutation involving the PAX6 gene in anterior segment anomalies and induction of lens development is discussed. In addition to chromosomal influences, in utero viral infection, particularly rubella, may play a role in some cases.
Abnormalities, Multiple↗
Ocular pathology of Lowe's syndrome in a female infant.
The ocular pathologic findings are presented in a case of a female infant with clinical and biochemical evidence of Lowe's syndrome. A small but increasing number of reports suggest that the mode of inheritance is not always sex-linked. The ocular histopathologic findings in the present case parallel those previously described for this syndrome. While the pathologic findings in other systems are variable, it is thought that the constellation of lens and anterior segment changes are sufficiently characteristic to identify cases of Lowe's syndrome.
Anterior Chamber↗
Massive congenital ocular toxoplasmosis.
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Brain↗
A program of eccentric-concentric strength training.
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Adult↗
Neurobehavioral effects of methyl N-butyl ketone and methyl N-amyl ketone in rats and monkeys: a summary of NIOSH investigations.
The results from four NIOSH investigations concerning the neurobehavioral effects of methyl n-butyl ketone (MBK) and methyl n-amyl ketone (MAK) on experimental animals are summarized. The investigations were initiated following clinical reports of neurologic sequelae in humans exposed to these ketone solvents. In order to explore both acute and chronic effects of MBK and MAK, two general types of studies were conducted: 1) neurophysiologic evaluation of monkeys and rats following chronic inhalation, and 2) behavioral effects in rats following oral or intraperitoneal administration. Results from chronic inhalation studies after 4 months of 1000 ppm MBK exposure (all exposures: 6 hrs/day, 5 days/week) showed the following: decreased motor nerve conduction velocities (NCV) in the ulnar and sciatic-tibial nerves, reduced amplitude of evoked muscle action potentials (MAP), lengthened latency of components of the visual evoked brain potential, decreased body weight, and hindlimb drag. Decrements in sciatic-tibial NCV and MAP amplitude were found after 9 months exposure to 100 ppm MBK. In contrast, exposure to approximately 1000 ppm MAK for 9 months had no adverse affects on neurophysiologic indicators of nervous system integrity. Dose-response investigations of the effects of MBK (oral) and MAK (ip) showed for both solvents a reduction in the response rate of rats trained on a multiple schedule of reinforcement.
Action Potentials↗
A comparative study of the effects of carbon monoxide and methylene chloride on human performance.
The purpose of this investigation was to determine whether similar carboxyhemoglobin (COHb) values obtained from inhaling carbon monoxide or methylene chloride have the same behavioral effects. The effects were assessed by the performance of 12 humans on a visual-manual, dual-task, and an auditory vigilance task. The results indicated that both substances in concentrations sufficient to produce 5-percent COHb significantly impaired human performance under difficult or demanding task conditions. The conclusion was that carbon monoxide, the main metabolite of methylene chloride, was responsible for the observed performance decrements.
Adolescent↗
Occurrence of benign glandular tissue in orbital aspirates. Importance of recognizing its lacrimal gland origin.
In the course of performing approximately 100 orbital aspirates, glandular epithelial inclusions were seen in three specimens from three patients. These inclusions, now recognized as benign and normal structures, initially led to false-positive cytologic results in two of the three cases. On the basis of reconstructing the clinical events, they appear to have been derived from the minor lacrimal glands in two cases and from the major lacrimal glands in the third. The potential hazard of regarding these glandular inclusions as indicating metastatic neoplasm is emphasized.
Adult↗