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Biomedical subjects

W K Anger

Publications and source records attributed to W K Anger.

At least 19 recordsLinked to original sources
PubMed1999

Neurobehavioral deficits in Persian Gulf veterans: evidence from a population-based study. Portland Environmental Hazards Research Center.

Reports of low-concentration nerve gas exposures during the Persian Gulf War have spurred concern about possible health consequences and refocused interest on the symptoms reported by many returning military veterans. The Portland Environmental Hazards Research Center is studying veterans from the Northwest USA who report persistent, unexplained "Persian Gulf" symptoms (cases) or who do not report those symptoms (controls). Of the first 101 veterans studied, cases differed substantially from controls on a broad range of psychological tests indicative of increased distress. A subgroup of cases was identified with objective deficits on neurobehavioral tests of memory, attention, and response speed.

Adult↗
PubMed1999

Test-retest reliability of psychological and neurobehavioral tests self-administered by computer.

A series of 12 psychological and 7 neurobehavioral performance tests were administered twice to a nonclinical normative sample with 1 week between administrations. The tests were presented in a self-administered computerized format. One week test-retest reliabilities were comparable to conventional administration formats. The results suggest that individual test reliability is not affected when tests are administered as part of an extensive multi-measure battery. Computer administered test reliability coefficients also were compared to a Mixed Format (computer-conventional) administration with mixed format reliabilities generally similar to the reliabilities of published conventional tests but also generally lower than same format testing. Compared to psychological test reliability, neurobehavioral test reliability appeared more vulnerable to decreases with mixed format testing. These conclusions should not be generalized to all computer implemented tests as the qualities of the test implementation will affect the outcome.

Adult↗
PubMed1997

Human neurobehavioral research methods: impact of subject variables.

Behavioral tests are used in work site and community research to detect and characterize the effects of neurotoxic chemical exposures in human populations, but the influence of subject variables on test performance has not been well studied in normal adult populations. This research sought to evaluate the impact of two variables, education and cultural group, on 18 widely used tests of neurotoxic insult. Behavioral tests from the two consensus neurotoxicity test batteries (established by the World Health Organization and the U.S. Agency for Toxic Substances and Disease Registry) were administered to 715 people aged 26-45 with 0-18 years of education, drawn from European descent United States majority, American Indian, African American, and Latin American populations. Education, cultural group, age, and gender affected the outcome of behavioral tests as revealed by ANOVA, MANOVA, and multiple regression techniques. Education, followed by cultural group, accounted for the most variance in the tests studied. More importantly, years of education and cultural group had 13-25% shared variance on the cognitive tests and highly significant interactions derived from ANOVA tests. This suggests that these factors should be controlled in the design of a study rather than in the statistical analysis. Because these factors can mimic a neurotoxic insult, failure to adequately control and analyze them could lead to inaccurate conclusions about the association between poor performance and neurotoxic insult.

Adult↗
PubMed1993

Individual-administered human behavioral test batteries to identify neurotoxic chemicals.

Most research demonstrating behavioral effects of occupational chemical exposures is produced in established laboratories using a consistent set or battery of tests. Exemplifying this tradition are batteries developed at Finland's Institute of Occupational Health, Milan's Institute of Occupational Health, Sweden's National Institute of Occupational Health, Australia's National Institute of Occupational Safety and Health, and at universities in the United States and other countries. In 1983, under the World Health Organization (WHO) aegis, experienced human occupational researchers recommended the Neurobehavioral Core Test Battery (NCTB) as a screening instrument to be administered by an individual to subjects exposed to chemicals believed to be neurotoxic. Health professionals from 50 cities in 27 countries distributed on every large continent have been trained to administer the NCTB according to its Operational Guide. Six issues need to be addressed regarding human-administered test batteries: (a) The critical role of individual-administered batteries to screen chemically exposed populations in a field increasingly dominated by computer-administered batteries; (b) selection criteria for tests to assess known and unknown chemicals; (c) utility of baseline data for study analysis and interpretation; (d) test battery validation; (e) availability and cost of inexpensive test batteries; and (f) equivalence of computer- and human-administered variants of the same tests.

Behavior↗
PubMed1993

Database programs as a literature research tool for the 1990s scientist: surveillance of neurotoxicology data.

As the mass of data and literature in any scientific field grows, it becomes increasingly difficult to recall details of early experiments and to relate findings in different studies. Simple database programs are available for the individual scientist to record and manipulate information, to provide a reliable and flexibly updatable memory aid, and to reveal new relationships through (re)organizations of information. Such programs can increase the efficiency of the literature research process and increase writing productivity by orders of magnitude. The use of database programs for literature research is exemplified with a behavioral neurotoxicology database revealing previously unappreciated consistencies in the human worksite research literature.

Databases, Bibliographic↗
PubMed1993

Comparison of performance from three continents on the WHO-Recommended Neurobehavioral Core Test Battery.

To address the need for standardized test batteries, an expert group convened by the World Health Organization (WHO) and the U.S. National Institute for Occupational Safety and Health during 1983 proposed the Neurobehavioral Core Test Battery (NCTB) to identify nervous system effects of chemical exposures in human populations worldwide. To determine the feasibility of using the NCTB in varied cultures, a cross-cultural assessment was conducted under WHO auspices. Data were collected in 10 countries of Europe, North and Central America, and Asia from over 2300 males and females who were not exposed to chemicals at work, within five age ranges between 16 and 65. Results suggest that performance on two NCTB tests (Simple Reaction Time, Benton Visual Retention) is very similar in a broad range of countries and that performance on four other NCTB tests (Santa Ana, Digit Symbol, Digit Span, Aiming) is relatively more variable from country to country, in both males and females. However, data collected from very poorly educated males in one country revealed very low performance levels suggesting that the NCTB may not provide an adequate reference group for identifying (behavioral) neurotoxic effects in such populations. More research is thus needed on evaluating neurotoxicity in poorly educated subjects.

Adult↗
PubMed1991

Animal test systems to study behavioral dysfunctions of neurodegenerative disorders.

The Eighth International Neurotoxicology Conference, Role of Toxicants in Neurological Disorders (1990), evaluated the evidence that chemical exposures may play a role in the development of neurodegenerative disorders. This article describes the major neurodegenerative disorders (Amyotrophic Lateral Sclerosis, Huntington disease, Parkinson disease, and Alzheimer disease) addressed at the conference, followed by a description of test systems or models developed to study behavioral aspects of these disorders in animals. However, due to the complexity of the disorders and the species in which they are found, fully-developed models in animals of neurodegenerative disorders are lacking. This suggests the need for a clear strategy for selecting behavioral tests in animals to study aspects of any neurodegenerative disorders. Such a strategy is here exemplified for Alzheimer disease (AD) as a prototypical neurodegenerative disorder. Since an animal model cannot provide the full range of effects of human neurodegenerative diseases, particularly AD which produces incompletely characterized cognitive deficits, a rodent model must at this time be drawn from multiple sources, including: (1) Tests currently used to identify in rodents deficits associated with AD; (2) tests to identify Alzheimer-related signs in patients; and, (3) tests that relate to theoretical constructs of human and animal cognition. A battery that draws from those sources could include tests of: (a) Spatial learning and memory (Morris Water Maze and Radial Arm Maze), (b) delayed recall match-to-sample; (c) serial response learning; and, (d) visual discrimination (e.g., vertical vs. horizontal stimuli). This battery will identify behavioral changes characteristic of early-, middle- and late-stage AD, afford the potential to relate the findings to theoretical constructs of cognition, and evaluate learning capabilities not previously studied in rodent models of neurodegenerative disorders.

Alzheimer Disease↗
PubMed1990

Worksite behavioral research. Results, sensitive methods, test batteries and the transition from laboratory data to human health.

Ample evidence demonstrates that many chemicals, at some concentration, affect the nervous system. Disastrous incidents resulting from food adulteration, medical experiments and pharmaceutical errors, and industrial and environmental exposures warn of the serious potential for neurotoxicants to affect human health. This article identifies the approximately 185 epidemiological behavioral neurotoxicology studies published through 1989 of extended workplace exposures to chemicals. Approximately 250 different tests have been administered to exposed workers in primarily cross sectional studies, and statistically significant decrements were reported in 43% of the approximately 1100 test/population administrations (virtually all 185 studies employed several of the 250 tests). In this research, 28 different chemicals as well as multiple chemical exposures have been studied. The most extensive findings are seen in research on carbon disulfide, lead, mercury, and multiple solvent exposures, although three or more independent studies also have been reported on workers exposed to styrene and organophosphates. Analyzing the consistent findings in these studies, they reveal a broad spectrum of cognitive, motor, and affective or personality changes. The most frequently reported functional deficits are in tests of intelligence, memory, spatial relations, coordination, and speed plus coordination. Individual behavioral measurement methods and significant test batteries that have been employed to assess changes in human nervous system functions to determine the degree of risk posed by new and established chemicals are described; two of those human behavioral test batteries are predicted to dominate research at the onset of the 1990's. There is a lack of parallelism between the human test methods found in these batteries and the US Environmental Protection Protection Agency (EPA) and Food and Drug Agency (FDA) guideline methods for pre-production screening of chemicals and food additives in animals, and it appears unlikely that the widely employed human and animal behavioral test batteries, as currently evaluated, could identify disease complexes newly suspected of having a chemical etiology.

Animals↗
PubMed1989

Human neurobehavioral toxicology testing: current perspectives.

Standardized tests or test batteries for neurotoxic effects are needed for premarket testing of chemicals (and related regulatory needs) and for the development of a neurotoxicity data base. Three widely known human test batteries based on past research findings and developed to screen for a broad range of neurotoxic effects are currently in use. One was developed by Finland's Institute of Occupational Health, one was recently recommended by the World Health Organization, and one was recently developed as a computer-implemented battery by US researchers. Each of these batteries assesses many frequently occurring neurotoxic effects, but each is limited by the lack of tests for some motor and sensory functions and affective responses that often occur following chemical exposures. Problems with field or worksite assessments using these test batteries involve age, education, socioeconomic, and job differences between exposed and comparison groups, and the lack of normative data on these batteries. To address some of these problems, the human neurobehavioral test batteries are currently undergoing reliability or validity assessments on a national and international scale. This will provide an assessment of their utility and accelerate development of a data base of neurotoxic effects of chemicals.

Behavior↗
PubMed1987

The long-term effects of a token economy on safety performance in open-pit mining.

A token economy that used trading stamps as tokens was instituted at two dangerous open-pit mines. Employees earned stamps for working without lost-time injuries, for being in work groups in which all other workers had no lost-time injuries, for not being involved in equipment-damaging accidents, for making adopted safety suggestions, and for unusual behavior which prevented an injury or accident. They lost stamp awards if they or other workers in their group were injured, caused equipment damage, or failed to report accidents or injuries. The stamps could be exchanged for a selection of thousands of items at redemption stores. Implementation of the token economy was followed by large reductions in the number of days lost from work because of injuries, the number of lost-time injuries, and the costs of accidents and injuries. The reductions in costs far exceeded the costs of operating the token economy. All improvements were maintained over several years.

Accident Prevention↗
PubMed1986

Behavioral technology for reducing occupational exposures to styrene.

We conducted a test of the usefulness of behavioral methods to control occupational health problems by reducing workers' exposures to toxic chemicals. Four plastics workers were trained in nine behaviors selected for potential to reduce their exposures to styrene, a common chemical with multiple toxic effects. Behavioral measures indicated that the workers quickly came to emit most of the behaviors. Measures of air samples indicated that large decreases in exposures to styrene accompanied the changes in behaviors for the three workers who had been selected because they most needed relief from their exposures and because they had opportunities to control their exposures by the ways they behaved.

Behavior Therapy↗
PubMed1986

Neurobehavioral evaluation of soil and structural fumigators using methyl bromide and sulfuryl fluoride.

Neurobehavioral functions affected by methyl bromide exposure were evaluated in California structural and soil fumigators using methyl bromide and sulfuryl fluoride. Sampling data revealed that structural fumigators are exposed for up to 1.5 hrs/day to 0-2.2 ppm methyl bromide and/or 10-200 ppm sulfuryl fluoride, and soil fumigators can be exposed to 2.3 ppm methyl bromide over an 8-hr day. Subjects were grouped for statistical analysis on the basis of exposure history: Those exposed primarily (80% or more of the work period with exposure potential) to methyl bromide (N = 32), primarily to sulfuryl fluoride (24), or to a combination of methyl bromide and sulfuryl fluoride (40-60% of each) for a minimum of one year (18), and those not exposed to high concentrations of any chemicals (29 Referents). Fumigators using methyl bromide reported a significantly higher prevalence of 18 symptoms consistent with methyl bromide toxicity than did Referents. Methyl bromide fumigators did not perform as well as Referents on 23 of 27 behavioral tests (chosen to reflect methyl bromide effects), and were significantly lower on one test of finger sensitivity and one of cognitive performance. These consistent differences suggest that even the low levels of methyl bromide found in fumigation today may produce slight neurotoxic effects. found in fumigation today may produce slight neurotoxic effects. The greater number of symptoms and reduced performance on all cognitive tests in sulfuryl fluoride fumigators compared to the Reference Group plus the absence of published research on this compound suggest that the data base for sulfuryl fluoride is inadequate.

Adult↗
PubMed1984

Neurobehavioral assessment of chronic low-level methyl bromide exposure in the rabbit.

The research reported here was intended to identify the concentration at which methyl bromide begins to produce neurotoxic effects in the rabbit, a species known to be sensitive to this compound. Rabbits were exposed via inhalation to 27 ppm methyl bromide over a period of 8 mo for a total exposure duration of 900 h. Biweekly neurobehavioral tests, consisting of the latency rates of the ulnar and sciatic nerves and the amplitude of the eyeblink reflex of the orbicularis oculi muscle, failed to uncover any untoward consequences of the exposures. The rabbits gained weight and otherwise appeared to be healthy. In contrast to reports available in the literature, these findings suggest that long-term exposures to methyl bromide, in the present concentration range, are tolerated by this species. Also detailed in this report is the course of recovery of a separate group of rabbits previously given subchronic exposures to 65 ppm methyl bromide. These animals developed severe neuromuscular losses and had impaired blink reflexes and body weights. The symptoms partially subsided within 6-8 wk after removal from the exposures, suggesting that recovery from a nonfatal but seriously debilitating exposure is possible.

Animals↗
PubMed1984

Toxicity evaluation of sub-chronic exposures to cyanogen in monkeys and rats.

A 6 mon (6 hr/day, 5 days/week) inhalation toxicity study was conducted with cyanogen gas using male rhesus monkeys (Macacca mulatta) and male albino rats (Charles River Strain) as experimental animals. Fifteen monkeys and 90 rats were divided into three groups of 5 monkeys and 30 rats. One group, the Controls, was not exposed to the test material; the other two groups were exposed to either 11 ppm or 25 ppm cyanogen. At the outset of exposures, there was a doubling of the rate of responding on a variable interval 2.9 min schedule of reinforcement in monkeys exposed to 25 ppm cyanogen, and increases were also seen in the monkeys receiving 11 ppm exposures; the increases were transitory as the rate returned to control levels before exposures were terminated. At the end of the 6 mon exposure, there were no effects in hematologic or clinical chemistry parameters attributable to the inhalation exposure to cyanogen. The electrocardiograms, and gross pathologic and histopathologic examinations of test animals were normal when compared with the Control animals. Total lung moisture content was significantly lower in monkeys exposed to either 11 ppm or 25 ppm cyanogen than in Control animals. Body weights were significantly lower in rats exposed to 25 ppm than in Controls. The results suggest that subchronic 25 ppm cyanogen exposures are marginally toxic, but the evidence on 11 ppm does not support a similar conclusion.

Animals↗
PubMed1981

Neurobehavioral effects of methyl bromide inhalation exposures.

Methyl bromide, a neurotoxic agent with a permissible US exposure limit of 20 ppm, is used primarily as a fumigant by an estimated 75,000 workers in the United States. This project was developed to evaluate the neurobehavioral effects of chronic and subchronic exposure to methyl bromide. One group of rats and rabbits was exposed to 65 ppm of methyl bromide for a total exposure of four 25-h weeks, or 100 h, and rats were exposed to 55 ppm of methyl bromide for a total exposure of 36 30-h weeks, or 1,080 h. Comparable control groups were given similar treatment, but no exposure. Behavioral tests of open field activity and limb coordination were conducted weekly during both phases of the experiment with rats, and eyeblink reflexes were measured weekly in rabbits. Nerve conduction velocity measurements were taken weekly from both rats and rabbits during the 65-ppm four-week exposures and monthly from rats during the 55-ppm 40-week exposures. Exposure to 65 ppm for four weeks significantly reduced eyeblink responses and nerve conduction velocity in rabbits but had no effect on rats. Exposure to 55 ppm of methyl bromide for 36 weeks had no effect on nerve conduction velocity, open-field activity, or coordination in rats.

Animals↗
PubMed1980

Effects of carbaryl on variable interval response rates in rats.

Sic male rats were trained on a variable interval 5 min schedule of reinforcement. Each rat, serving as its own control, was given itraperitoneal (IP) and intramuscular (IM) injections of 1, 3, 5, and 10 mg/kg l-naphthyl N-methylcarbamate (carbaryl). There were significant decreases in response rate following 3, 5, and 10 mg/kg IP injections and 5 and 10 mg/kg IM injections of carbaryl.

Animals↗
PubMed1979

Effects of oral and intramuscular carbaryl administrations on repeated chain acquisition in monkeys.

A type of learning task was utilized to determine the effective dose of carbaryl on Macaca fascicularis for both oral and in routes of administration. Monkeys were required to press four buttons in a set order; the order was changed daily. A baseline reversal design was utilized to test all animals several times at each concentration. The im carbaryl injections resulted in consistent, statistically reliable decrements in total session time and increases in errors at 5 and 10 mg/kg for the 4 animals in this section of the experiment, but produced no change in performance at 1 mg/kg. Errors increased in 3 of 4 monkeys after 3 mg/kg injections. Oral doses as high as 50 mg/kg were not consistently effective in changing performance on the task in any of 5 animals included in this section of the experiment. Some support was given to the suggestion that monkeys are more tolerant of carbaryl than are rats. These are the first reported effects (other than the LD50) of carbaryl in monkeys.

Administration, Oral↗