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Biomedical subjects

J Agnew

Publications and source records attributed to J Agnew.

At least 37 records · Page 2Linked to original sources
PubMed1993

Age and fatal work-related falls.

In the work environment, an increased risk of fatal injury from falls is seen at ages not normally considered to be old. This study examined fatality data from a National Institute for Occupational Safety and Health death certificate database and from Occupational Safety and Health Administration (OSHA) investigations to analyze the relationship of age to fatal work-related falls. For 1980 to 1986, death certificates reported 43,505 fatal work injuries in men, 4179 of which were from falls. Fatality rates from falls showed an increase for older workers beginning with the age group of 45-54, whereas fatal injury rates for other work-related causes did not increase until the age group of 55-64. OSHA investigations of 996 fatal work-related falls in 1984-1986 reported that falls from ladders accounted for 20% of fatal falls in workers aged 55 and over, significantly more than the average of 9% of all falls for workers of all ages. OSHA data also showed that fatal falls among older workers were associated with lower energy of impact, which means that the height of fatal falls tends to decrease with increasing age.

Accidental Falls↗
PubMed1992

Management of the airway in oral and oropharyngeal resections.

A tracheostomy is the traditional method of maintaining an airway after major oral and oropharyngeal resections. Postoperative endotracheal intubation was used for 19 patients who underwent major oral and oropharyngeal resections over a 3-year period at the Royal Adelaide Hospital. This appears to be a safe alternative to tracheostomy if intensive care facilities are available.

Evaluation Studies as Topic↗
PubMed1992

Computer models of hearing aid transducers for integrated circuit design.

Electronic circuit modeling using computer-based simulation tools is well established and device models are available for common electronic components. However, acoustic models of audio transducers for use during integrated circuit design are not readily available. This causes difficulty for designers of audio amplifiers, and increases the uncertainties of a successful silicon integration of a circuit design. This paper reports on a technique for the creation of electroacoustic models of hearing aid microphones and receivers that can be connected to an amplifier under design, and incorporated into PSPICE simulations. Verification of the technique and models was performed by comparing measured frequency response data with graphs created by PSPICE modeling. The conclusions were that the method developed for creating these models, and the models themselves, were accurate enough to be used for acoustic simulations of frequency response performance during amplifier design, and gave results comparable to data obtained from breadboard measurements of the same circuits.

Computer Simulation↗
PubMed1992

Impairment of lung mucociliary clearance in pigeon fanciers.

Lung mucociliary clearance was measured in 15 pigeon fanciers. The study group was subdivided into two: a precipitin-positive group (n = 10; mean +/- SEM age 45 +/- 5 years) with circulating blood precipitins and a precipitin-negative group (n = 5; mean +/- SEM age 40 +/- 3 years) without. Clearance was measured using an objective, noninvasive radioaerosol technique. The data for both groups were compared with those of matched control groups of healthy subjects. The mean +/- SEM area under the tracheobronchial retention curves (AUC) over the 6-h observation period was 257 +/- 27 %h for the precipitin-positive group compared with 177 +/- 16 %h for its control group (p = 0.02)--a high AUC value denoting slow clearance. That for the precipitin-negative group was 282 +/- 34 %h compared with 150 +/- 15 %h for its control group (p = 0.02). Our study illustrates in pigeon fanciers involvement of the conducting airways in that a major defense mechanism of the airways--namely, mucociliary clearance--is substantially compromised. The presence or absence of precipitins appears not to be related to the degree of mucociliary clearance impairment.

Bird Fancier's Lung↗
PubMed1991

Reproductive hazards of fire fighting. I. Non-chemical hazards.

Fire fighters are regularly exposed to chemical and non-chemical agents that have known or suspected adverse effects on reproductive health. Although chemical agents have received some attention, non-chemical hazards such as heat, noise, and physical exertion have only recently been examined for their reproductive effects. There is evidence that heat, noise, and physical exertion may affect various endpoints of reproductive health, including fertility, fetal loss, and growth parameters of the offspring. In particular, hyperthermia, a major fire fighting hazard, has been shown to impair male fertility and may also be teratogenic. Further study of the potential reproductive effects of this and other common non-chemical agents in the fire environment is needed to ensure the reproductive health of male and female fire fighters.

Animals↗
PubMed1991

Reproductive hazards of fire fighting. II. Chemical hazards.

Studies of the health of fire fighters have historically focused on non-malignant respiratory disease and cancer. More recently, concerns have surfaced about reproductive health effects in many areas of the workforce, including fire fighting. These concerns prompted this review of chemical exposures that may contribute to adverse reproductive health outcomes in male as well as female fire fighters. A review of the industrial hygiene literature was undertaken to identify agents commonly found in fire smoke. These agents were then examined for evidence of reproductive toxicity or mutagenicity/carcinogenicity. This profile of chemical agents and their reproductive toxicities permits a qualitative determination that fire fighters are exposed to potential reproductive toxicants as a part of their normal fire fighting duties. Considerations for mitigating these risks are also discussed.

Air Pollutants, Occupational↗
PubMed1991

Dose-related subclinical neurobehavioral effects of chronic exposure to low levels of organic solvents.

One hundred eight-seven workers (mean age +/- SD; 42 +/- 8.8 years) in two paint manufacturing plants were examined to determine if sustained low-level exposure to mixed organic solvents resulted in the painters' syndrome (a psycho-organic syndrome). The test battery consisted of a medical and occupational questionnaire, the Present State Examination, the Zung Depression Scale, the Scandinavian Questionnaire 16, a neuropsychological battery, and vibration thresholds. Solvent exposure, expressed as total hydrocarbon of combined selected solvents, was quantitated using 13-15 years of personal breathing zone samplings. Linear regression analysis controlling for several confounding variables demonstrated significant correlations between increasing exposure to mixed organic solvents and neurobehavioral performance for vibration threshold and several neuropsychological tests. Dose-related effects of chronic solvent exposure on neurobehavioral outcomes (all subclinical) were shown, but "typical" symptoms characteristic of the painter's syndrome were not found.

Adult↗
PubMed1991

A quantitative approach to the characterization of cumulative and average solvent exposure in paint manufacturing plants.

Previous reports have attributed a range of neurobehavioral effects to low-level, occupational solvent exposure. These studies have generally been limited in their exposure assessments and have specifically lacked good estimates of exposure intensity. In the present study, the authors describe the development of two exposure variables that quantitatively integrate industrial hygiene sampling data with estimates of exposure duration--a cumulative exposure (CE) estimate and a lifetime weighted average exposure (LWAE) estimate. Detailed occupational histories were obtained from 187 workers at two paint manufacturing plants. Historic industrial hygiene sampling data for total hydrocarbons (a composite variable of the major neurotoxic solvents present) were grouped according to 20 uniform, temporally stable exposure zones, which had been defined during plant walk-through surveys. Sampling at the time of the study was used to characterize the few zones for which historic data were limited or unavailable. For each participant, the geometric mean total hydrocarbon level for each exposure zone worked in was multiplied by the duration of employment in that zone; the resulting products were summed over the working lifetime to create the CE variable. The CE variable was divided by the total duration of employment in solvent-exposed jobs to create the LWAE variable. The explanatory value of each participant's LWAE estimate in the regression of simple visual reaction time (a neurobehavioral test previously shown to be affected by chronic solvent exposure) on exposure was compared with that of several other exposure variables, including exposure duration and an exposure variable based on an ordinal ranking of the exposure zones.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemical Industry↗
PubMed1991

Comparison of computerized and examiner-administered neurobehavioral testing techniques.

To better understand the relationship of newly developed computerized neurobehavioral tests to their examiner-administered counterparts, performance on four pairs of tests was compared among 185 solvent-exposed workers in the paint manufacturing industry. Two approaches to the comparison of the test methods (computer or examiner) were employed: (1) the multitrait-multimethod correlation matrix and (2) linear regression modeling of the difference scores between pairs of tests (same functional domain, different test formats). The data revealed that the validity criteria of the multitrait-multimethod technique were met for the tests of simple visual reaction time and attention-concentration (digit symbol substitution). Linear regression analyses demonstrated that the digit symbol substitution and visual memory test pairs were differentially affected by age, vocabulary, solvent exposure, or manual dexterity. Overall, this latter approach holds promise as a means of understanding test format similarities and differences.

Adult↗
PubMed1991

Solvent-associated olfactory dysfunction: not a predictor of deficits in learning and memory.

OBJECTIVE: The aim of the study was to evaluate associations between olfactory dysfunction and aberrations in learning and memory after chronic occupational exposure to mixed hydrocarbon solvents. METHOD: This was a cross-sectional, epidemiologic study of 187 paint manufacturing workers. The authors administered quantitative tests of olfactory function (the University of Pennsylvania Smell Identification Test) and neurobehavioral function (eight computer- and examiner-administered tests of learning and memory) to workers for whom detailed information was available on lifetime occupational exposure to solvents. RESULTS: Olfactory function test scores were positively correlated with performance on seven of eight of the tests of learning and memory in bivariate analyses. After adjustment for important confounding variables (i.e., age, vocabulary score, and cumulative exposure to hydrocarbon solvents) with multiple linear regression, olfactory function scores predicted performance only on the Wechsler Memory Scale Delayed Logical Memory test. CONCLUSIONS: Overall, the data did not reveal that olfactory dysfunction was correlated with decrements in various memory functions.

Adult↗
PubMed1990

Solvent-associated decrements in olfactory function in paint manufacturing workers.

To assess the effects of low-level organic solvent exposure on olfactory function, a cross-sectional study in paint manufacturing workers was undertaken. Workers in two paint manufacturing facilities (N = 187) were tested using the University of Pennsylvania Smell Identification Test (UPSIT), a standardized, quantitative test of olfactory function. Industrial hygiene air samples over the past 13-15 years revealed that average solvent exposures in these plants were 2-40% of the existing threshold limit values for the three chemicals measured. Stratification by smoking status revealed evidence of dose-related decrements in olfactory function (p = .01) only in non-smokers. Furthermore, those nonsmoking workers in the highest exposure category had UPSIT scores below the fifth percentile for their age. These results suggest that solvents may cause nervous system dysfunction at lower levels than previously suspected, and that the olfactory system may be a critical target organ for the neurotoxic effects of solvents and other chemicals.

Adult↗
PubMed1990

Subclinical neuropsychiatric effects of chronic low-level solvent exposure in US paint manufacturers.

In the present study, 187 workers at two US paint manufacturing plants were assessed for symptoms of painters syndrome using the Zung Depression Index, Scandinavian Questionnaire 16, and the Present State Exam. No significant associations were found between solvent exposure and total scores, although a sum of individual questions related to depression on the Present State Exam was found to be related to both health status and exposure. The clinical relevance of these findings is discussed. Overall, exposure was not associated with the constellation of symptoms characteristic of the painters' syndrome.

Adult↗
PubMed1989

Deaths from asphyxiation and poisoning at work in the United States 1984-6.

A review of 4756 deaths investigated by the Occupational Safety and Health Administration (OSHA) in 1984-6 found 233 deaths from asphyxiation and poisoning, excluding asphyxiations from trench cave-ins. The highest rates were in the oil and gas industry and in utilities. Toxic gases were the largest group (65) followed by simple asphyxiants (48), mechanical causes (42), and solvents (35). Deaths from solvents were significantly more likely in young workers. Nine deaths were caused by improper air supply to respirators and five by recreational inhalation of gas or vapours. Of the 146 deaths in confined spaces, only 12% were in rescuers, fewer than previously reported.

Asphyxia↗
PubMed1988

Age-related sex differences in verbal memory.

Verbal learning and memory were studied in 196 healthy men and women aged 40 to 89. The Rey Auditory Verbal Learning Task (RAVLT), a 15-word list, was presented over five trials followed by free recall after each trial. A recognition trial of 50 words subsequently was administered. A stepwise regression that examined the contributions of age, sex, and vocabulary on the five trials of the RAVLT showed that age and sex accounted for a significant portion of the variance on each trial. Vocabulary accounted for a significant portion of the variance only on trials 4 and 5. The recognition trial was not affected by age, sex, or vocabulary. Men had lower scores overall as compared to women. In the older age group (ages 66-89), this difference was significant on trials two through five. Possible mechanisms that may underlie these age-related sex differences in learning curves are discussed.

Adult↗
PubMed1988

Vitamin D and parathyroid hormone and bone mineralisation in adults with cystic fibrosis.

Vitamin D and parathyroid hormone concentrations were assessed in 31 adults with cystic fibrosis (mean age 24, range 17-52 years), in 28 of whom the bone mineral index in the forearm was also determined. Serum 25-hydroxyvitamin D was subnormal in eight patients, of whom five were receiving vitamin D supplements in standard doses. 1,25-dihydroxyvitamin D and parathyroid hormone concentrations showed no consistent abnormalities. The bone mineral index was lower in patients with cystic fibrosis (p less than 0.02) than in controls. Five patients with unequivocally reduced bone mineral index had a subnormal mean serum 25-hydroxyvitamin D and significantly worse lung function than the other patients. There was a positive correlation between age and bone mineral index (r = 0.68, p less than 0.001). Thus a significant proportion of patients with cystic fibrosis living in a temperate climate are at risk of vitamin D deficiency. Osteopenia is common and is probably related to a combination of hypovitaminosis D, delay in puberty, hypo-oestrogenism in women, and reduced physical activity, rather than to secondary hyperparathyroidism. Since most patients with deficiency of 25-hydroxyvitamin D were receiving oral supplements, parenteral vitamin D supplementation may be appropriate for selected patients who are unable to maintain adequate 25-hydroxyvitamin D concentrations despite oral vitamin D supplements.

Adolescent↗
PubMed1988

Maximal aerobic capacity at several ambient concentrations of CO at several altitudes.

To assess the nature of the combined effect of the hypoxias of altitude (ALT) and CO exposure, 11 men and 12 women nonsmokers served as subjects in a double-blind experiment. The exposure conditions were four ambient CO levels (0, 50, 100, and 150 ppm) at each of four ALT (55, 1,524, 2,134, and 3,048 m). Each subject, after attaining the required ALT and ambient CO level, performed a maximal aerobic capacity test (VO2max). Blood samples were obtained before, at 50-W, 100-W, 150-W, and maximum work loads and at the 5th min of recovery. Blood were analyzed for hemoglobin, hematocrit, plasma proteins, lactates, and carboxyhemoglobin (HbCO). VO2max was similar at 55 and 1,524 m and decreased by 4 and 8% from the 55-m value at 2,134 and 3,048 m, respectively. On the basis of all statistical analyses, we concluded that VO2max values measured in men were only slightly diminished due to increased ambient CO. HbCO attained at maximum was highest at 55 m and lowest at 3,048 m. Women's HbCO concentrations were lower than men's. At maximal work loads CO shifted into extravascular spaces and returned to the vascular space within 5 min after exercise stopped. The independence of altitude and CO hypoxias on parameters of the maximum aerobic capacity test and a decrease in the CO to HbCO uptake with increasing altitude were demonstrated and attributed in part to the decrease in driving pressure of CO at altitude.

Adolescent↗