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Biomedical subjects

K H Kilburn

Publications and source records attributed to K H Kilburn.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Airway disease in non-smoking asbestos workers.

Ninety-seven non-cigarette-smoking white male insulators from the midwestern United States had significantly reduced forced expiratory volume in 1 second (FEV1.0) (P less than .0017) and forced expiratory flow from 75 to 85% of expired volume (FEF75-85) (P less than .042) when compared to a reference population of Michigan male nonsmokers. There were parenchymal opacities with a profusion of 1/0 or greater in 7 and pleural changes in 13 of these 97 nonsmokers. Asbestos, in the absence of cigarette smoke effects and other diseases, appears to decrease airflow, probably by the distortion of small airways (less than 2mm) by peribronchiolar fibrosis. This stiffening of the lung parenchyma protects midflow (FEF25-75) as the fibrosis increases the lung's radial traction on airways larger than 2 mm. This observation contributes to the natural history of physiological impairment due to asbestos disease.

Adult↗
PubMedDate not supplied

Formaldehyde impairs memory, equilibrium, and dexterity in histology technicians: effects which persist for days after exposure.

Results of neurobehavioral testing in 305 histology technicians were studied by regression analysis with age, years of cigarette smoking, and hours per day of exposure to formaldehyde and to solvents as major independent variables. Increasing age was associated with poorer performance on visual memory, block design, trails, dexterity by pegboard, sharpened-Romberg, finger writing, as well as with longer choice reaction time. Increased daily hours of exposure to formaldehyde were correlated with reduced performance on story memory, visual memory, digit span, pegboard and sharpened-Romberg, as well as with errors on trails. Exposure to solvents was associated only with diminished recall of story.

Adult↗
PubMedDate not supplied

Neurobehavioral dysfunction in firemen exposed to polycholorinated biphenyls (PCBs): possible improvement after detoxification.

Fourteen firemen exposed to polychlorinated biphenyls (PCBs) and their byproducts generated in a transformer fire and explosion had neurophysiological and neuropsychological tests 6 mo after the fire. They were re-studied 6 wk later after undergoing 2-3 wk of an experimental detoxification program consisting of medically supervised diet, exercise, and sauna. A case-control comparison with firemen matched from the same department, but who did not participate in controlling the transformer fire, had shown significant impairment of memory for stories, visual images, and digits backwards. Cognitive function was impaired for block design, identifying embedded figures, and design association and recognition using Culture Fair. Making of trails and choice reaction time, which measured cognitive function and perceptual motor speed, were also impaired. These signs of protracted neurobehavioral impairment were attributed to PCBs and heat-produced byproducts. No relationship, however, was found between the firemen's serum or fat levels of PCBs as Arochlor 1248 and their type or degree of neurobehavioral impairment. Retesting following the detoxification program showed significantly improved scores on: three memory tests, block design, trails B, and embedded figures. Thus, there was significant reversibility of impairment after the detoxification interval. However self-appraisal scores for depression, anger, and fatigue--which were initially elevated--and for vigor--which was reduced--did not change across this interval.

Adult↗
PubMedDate not supplied

Neurobehavioral impairment and seizures from formaldehyde.

Three patients were evaluated for effects of formaldehyde on central nervous system function. Three patients had used formalin, formaldehyde with or without phenol, to fix whole animals for 14-30 y, and a fourth patient was covered several times by formaldehyde and phenol rainout from manufacturing spills. All were disabled, and two had developed seizures. They had elevated mood state scores (82 to 162) and elevated symptom frequency scores (111 to 138), compared with referent subjects. There was excessive fatigue, somnolence, headache, difficulty remembering, irritability, and instability of mood. Compared with referents, choice reaction time was prolonged in four of four (4/4) subjects, blink latency was delayed in 2/2, balance was abnormal in 3/4, and visual fields were constricted in 2/3. Cognitive functions, measured by Culture Fair, block design, and digit symbol tests, were impaired in all. Delayed verbal recall and visual reproduction were impaired in 3/4. Perceptual motor speed on slotted pegboard and trail making A and B tests was reduced in 4/4. Errors on fingertip number writing were abnormal in all. Long-term memory was decreased in only one. Extensive use of formaldehyde at work or repeated airborne exposure to formaldehyde and phenol appears to have impaired central nervous system function.

Central Nervous System↗
PubMedDate not supplied

Prediction equations for simple and visual two-choice reactions times in environmental neurotoxicology.

To provide preliminary prediction equations for simple visual and two-choice visual reactions times, timed from the appearance of the letter A or S on a computer screen to cancellation, we modeled 264 randomly selected subjects from voter registration rolls in Arizona and Louisiana. These predicted values, validated by comparison to observed values and coefficients, were compared with those from a second population in California. We tested ability to detect abnormality by measuring a trichloroethylene-exposed population aged 17-70 y. The natural logarithm of simple visual reaction time was independent of age and other factors. The natural logarithm of two-choice visual reaction time was increased by age. These equations predict performance of groups that are studied with respect to neurobehavioral effects of chemicals, and the equations distinguish exposure and nonexposure for the range of adult ages. To define abnormality of individual subjects, we suggest use of the predicted value, plus 1.5 standard deviations; in this study, 8% of the model group was selected as abnormal.

Adult↗
PubMedDate not supplied

Population-based prediction equations for neurobehavioral tests.

Quantitative assessment of neurobehavioral function appraises brain injury from inhaled chemicals. Contemporary predicted values for tests useful in epidemiological studies have been developed with step-wise linear regression. In instances in which age and education do not match those of control groups, these equations assist in the interpretation of results of examinations of individual subjects and pilot studies. In this study, investigators considered brain function tests to be analogous in concept to pulmonary function tests. The authors used the tests to assess 293 adults in three unexposed groups from different areas of the United States. The subjects, who were contacted at random from voter registration rolls, were compensated for their time. The tests included balance, reaction time, strength, hearing, visual performance and cognitive recall, and perceptual motor and memory functions. Regression equations modeled the performance of each test and the influences of demographic factors. The investigators retained all influential factors in the equations. Age was a significant predictor for most tests. Education attainment was not a factor in any of the physiological measures, but it was a determinant in many psychological tests. Prediction equations assist investigators in the quantitative testing of chemically exposed individuals and other brain-injured individuals. The investigators verified the equations against other groups, including additional unexposed populations.

Adolescent↗
PubMedDate not supplied

Neurobehavioral impairment and symptoms associated with aluminum remelting.

The author's objective was to assess whether aluminum reclamation (recycling) exposure in a plant in the southeastern United States was associated with neurobehavioral and pulmonary impairment and symptoms. The author made cross-sectional comparisons of 41 workers to 32 local and 66 regional referents to assess whether aluminum recycling was associated with neurobehavioral and pulmonary impairment and symptoms. Methods included neurophysiological, psychological, and pulmonary-function tests; a Profile of Mood States (POMS); and questionnaires. The exposed subjects had slower simple and choice reaction times than referents (i.e., 77 milliseconds [ms] versus 137 ms, respectively [p < .0001]); balance in the exposed subjects, measured as sway speed (with eyes closed), was .32 cm/s faster than for referents (p < .005); and color discrimination was less acute in exposed subjects (p < .0001). In the exposed versus referent subjects, Culture Fair scores were lower by a factor of 8.3 (p < .0001), Trail Making A was 10 s longer (p < .001), Trail Making B was 50 s longer (p < .0001), peg placement required an additional 9 s (p < .008), and POMS scores were fourfold higher (p < .0001). These described differences were not explained by age, bias, or confounding factors. Workers had more neurobehavioral, rheumatic, and respiratory symptoms than did referents. The author attributed the differences between the two groups to chemical exposures from aluminum remelting, including aluminum, manganese, vinyl chloride monomer, and other chemicals. Workplace air could not be sampled, but because a problem was identified, levels of these, as well as other chemicals, should be measured in future studies.

Adolescent↗