Psychosocial and work organization risk factors for cumulative trauma disorders in the hands and wrists of newspaper employees.
Explore the source record for details and available documents.
Computer Terminals↗
Biomedical subjects
M R Petersen
Publications and source records attributed to M R Petersen.
Progression of diabetic retinopathy after pancreas transplantation. The University of Michigan Pancreas Transplant Evaluation Committee.
The progression of diabetic retinopathy after combined pancreatic and kidney transplantation was studied in eight patients for 12 to 49 months. Four patients who had rapid pancreatic graft failure constituted a control group for comparison with four patients who retained functioning grafts. Using Fisher's exact probability test, the authors found no posttransplantation difference between the two groups in visual acuity lost, severity of diabetic macular edema, extent of capillary closure, progression of preretinal gliosis, development of disc or preretinal neovascularization, or worsening of the severity of the retinopathy. Achievement of normoglycemia by pancreatic transplantation is not effective in halting the progression of diabetic retinopathy in patients who already have severe diabetic microangiopathy joined the current follow-up.
Adult↗
Absolute auditory thresholds in three Old World monkey species (Cercopithecus aethiops, C. neglectus, Macaca fuscata) and humans (Homo sapiens).
We investigated the absolute auditory sensitivities of three monkey species (Cercopithecus aethiops, C. neglectus, and Macaca fuscata) and humans (Homo sapiens). Results indicated that species-typical variation exists in these primates. Vervets, which have the smallest interaural distance of the species that we tested, exhibited the greatest high-frequency sensitivity. This result is consistent with Masterton, Heffner, and Ravizza's (1969) observations that head size and high-frequency acuity are inversely correlated in mammals. Vervets were also the most sensitive in the middle frequency range. Furthermore, we found that de Brazza's monkeys, though they produce a specialized, low-pitched boom call, did not show the enhanced low-frequency sensitivity that Brown and Waser (1984) showed for blue monkeys (C. mitis), a species with a similar sound. This discrepancy may be related to differences in the acoustics of the respective habitats of these animals or in the way their boom calls are used. The acuity of Japanese monkeys was found to closely resemble that of rhesus macaques (M. mulatta) that were tested in previous studies. Finally, humans tested in the same apparatus exhibited normative sensitivities. These subjects responded more readily to low frequencies than did the monkeys but rapidly became less sensitive in the high ranges.
Adult↗
Lung volume reference values for blue collar workers not exposed to occupational respiratory hazards.
Epidemiologic research into occupationally related lung disease often requires the comparison of a study group with an external nonexposed comparison group. In order to develop such an external comparison group, blue collar workers, who had no obvious adverse occupational pulmonary exposure, performed simple spirometry, were administered a standard questionnaire, and had standard posterior-anterior and lateral chest radiographs taken. Prediction equations were established for three indices of lung volume, namely total lung capacity, residual volume, and their ratio, for various combinations of race, sex, and smoking groups. Asymptomatic non-smokers with normal radiograph results were then extracted from the overall group, and separate prediction equations were established. The relationship between age and total lung capacity is discussed.
Adult↗
Symptoms, ventilatory function, and environmental exposures in Portland cement workers.
Data on respiratory symptoms and pulmonary function were obtained for 2736 Portland cement plant workers and 755 controls. Personal dust samples contained a geometric mean concentration of 0.57 mg/m3 for respirable dust and 2.90 mg/m3 for total dust. Cement workers and controls had similar prevalences of symptoms, except that 5.4% of the cement workers had dyspnoea compared with 2.7% of the controls. The mean pulmonary function indices were similar for the two groups. Among cement plant workers, the prevalence of chronic phlegm increased with tenure whereas the prevalence of wheezing increased with both tenure and current dust level. Other symptoms and pulmonary function indices were not significantly related to exposure.
Adult↗
Auditory duration discrimination in Old World monkeys (Macaca, Cercopithecus) and humans.
Auditory duration DLs at 2.0 kHz were measured in Old World monkeys (Macaca, Cercopithecus) and humans using a go, no-go repeating standard AX procedure and positive reinforcement operant conditioning techniques. For a 200-ms standard, monkey DLs were 45-125 ms, compared to 15-27 ms for humans. Weber fractions (delta T/T) for all species were smallest at standard durations of 200-400 ms and increased as standard duration decreased to 25 ms. Varying intensity from 30-70 dB SPL had only minor effects on DLs, except at the lowest levels tested, where DLs were elevated slightly. Monkeys had difficulty discriminating duration decrements, in contrast to humans. Results are discussed in relation to other comparative psychoacoustic data and primate vocal communication, including human speech.
Animal Communication↗
Application of a pilot study to the development of an industrial hygiene sampling strategy.
An industrial hygiene pilot study was conducted to estimate the concentrations of respirable dust likely to be encountered during the personal sampling phase of a large-scale morbidity study of the portland cement industry. An analysis of the pilot study data showed little variability in exposure for subjects working in the same job in the same area of the same plant. Thus, one could estimate mean exposure by sampling several subjects rather than sampling the same subject several times. It was concluded that for statistical considerations, the best approach would be to sample four jobs per area and six subjects per job. Practical considerations required one more often to select six jobs with two subjects per job, however. Overall, the collection of fewer samples was required during the morbidity study than was anticipated originally. In turn, the reduction in the number of samples to be collected resulted in a savings of time and resources.
Dust↗
Frequency and intensity discrimination in humans and monkeys.
Frequency and intensity DLs were compared in humans and monkeys using a repeating standard "yes-no" procedure in which subjects reported frequency increments, frequency decrements, intensity increments, or intensity decrements in an ongoing train of 1.0-kHz tone bursts. There was only one experimental condition (intensity increments) in which monkey DLs (1.5-2.0 dB) overlapped those of humans (1.0-1.8 dB). For discrimination of both increments and decrements in frequency, monkey DLs (16-33 Hz) were approximately seven times larger than those of humans (2.4-4.8 Hz), and for discrimination of intensity decrements, monkey DLs (4.4-7.0 dB) were very unstable and larger than those of humans (1.0-1.8 dB). For intensity increment discrimination, humans and monkeys also exhibited similar DLs as SL was varied. However, for frequency increment discrimination, best DLs for humans occurred at a high (50 dB) SL, whereas best DLs for monkeys occurred at a moderate (30 dB) SL. Results are discussed in terms of various neural mechanisms that might be differentially engaged by humans and monkeys in performing these tasks; for example, different amounts of temporal versus rate coding in frequency discrimination, and different mechanisms for monitoring rate decreases in intensity discrimination. The implications of these data for using monkeys as models of human speech sound discrimination are also discussed.
Acoustic Stimulation↗
Prevalence of radiographic appearance of pneumoconiosis in an unexposed blue collar population.
Blue collar employees currently working in environments free from exposure to respiratory hazards were examined with chest radiography and a standard occupational history questionnaire. Workers who had worked for a total of 5 yr or more in previous jobs with possible hazardous respiratory exposures were excluded. Each radiograph was read independently by 3 NIOSH-certified "B" readers. For small opacities, the median profusion was accepted as a summary reading. The 1,422 readable films represented a population of 50.6% males, 49.4% females, 52.5% whites, 44.2% blacks, 47.0% current smokers, and 38.5% nonsmokers. The mean age was 33.8 yr, with a range from 16 to 70 yr. Small opacities of profusion greater than or equal to 1/0 were identified in only 3 (0.21%) of the radiographs--2 with small rounded opacities and 1 with small irregular opacities. Small irregular opacities of profusion category greater than or equal to 0/1 were statistically associated with age, gender, and pack-years of smoking. The results suggest that using the median of 3 independent readings should rarely result in interpretation of chest radiographs as "positive" for pneumoconiosis in active workers who have not had significant dust exposure.
Adolescent↗
Neural lateralization of vocalizations by Japanese macaques: communicative significance is more important than acoustic structure.
The study was designed to determine whether the neural lateralization of vocal perception in Japanese macaques depends on the acoustic properties of the calls used or their communicative significance. Four monkeys--two Japanese macaques and two comparison macaques--were trained to discriminate among monaurally presented exemplars of two classes of vocalizations from the Japanese macaque's repertoire. Once the subjects mastered the discrimination, they performed at equivalent accuracy levels for 150 sessions. However, during this time the Japanese monkeys showed a right ear performance advantage, whereas the comparison monkeys showed no ear advantage. In order to assess whether the comparison and Japanese monkeys were attending to the same acoustic cue when performing the discrimination, a generalization test was conducted with 27 novel vocalizations. The individual monkeys' generalization gradients were highly similar and revealed that all subjects were in fact listening to the same feature of the calls. These findings, coupled with the fact that the calls were of biological significance to the Japanese monkeys alone, suggest that the laterality effect is related, in some fashion, to the communicative valence of the signals rather than their purely physical characteristics.
Animals↗
Chronic inhalation of diesel exhaust and coal dust: effect of age and exposure on selected enzyme activities associated with microsomal cytochrome P-450 in rat lung and liver.
Male Fisher-344 rats were exposed by inhalation to low levels of diesel exhaust and coal dust, alone or in combination, or to filtered air, 7 h/d, 5 d/wk for 24 mo. Cytochrome P-450-associated benzo[a]pyrene hydroxylase and 7-ethoxycoumarin deethylase activities were assayed in lung and liver microsomes after 3, 6, and 24 mo. Age-related changes in enzyme activities were observed, but they were not altered by the exposures. When the data were adjusted for age, only one difference was observed. Lung benzo[a]pyrene hydroxylase activity in rats exposed to diesel exhaust and coal dust in combination was lower than that in animals exposed to coal dust alone (2.8 versus 4.4 pmol/min X mg protein). Neither value, however, differed significantly from the filtered-air controls, and no differences were observed in the other lung and liver activities. The data suggest exposure of the rats to diesel exhaust and/or coal dust had little or no effect on the selected lung and liver cytochrome P-450 activities under the conditions of the experiment.
Age Factors↗
Mutagenic characterization of synthetic fuel materials by the Ames/Salmonella assay system.
Solvent refined coal (SRC) distillates produced by 2 different pilot plant processes were compared for mutagenicity using the Ames/salmonella assay. The high-molecular-weight, high-boiling SRC distillates were fractionated into their various constituent chemical classes for Ames analysis. In each case, the major portion of the mutagenic activity contained in the crude materials was recovered in the basic and in the tar fractions. Little or no activity was found in the neutral. aliphatic, or neutral polyaromatic hydrocarbon (PAH)-enriched fractions. The most active of the SRC subfractions were comparable in mutagenicity to benzo[a]pyrene, but substantially less active than 2-aminoanthracene.
Animals↗
Pulmonary function and symptoms in herbal tea workers.
Explore the source record for details and available documents.
Adult↗
Species-specific perceptual processing of vocal sounds by monkeys.
Monkeys of four species were trained to discriminate between sets of natural tonal calls of Japanese macaques (Macaca fuscata) by the position of a frequency-inflection peak or by initial pitch. The Japanese macaques consistently performed best on peak position and the other species on pitch. The results imply special strategies for perceptional processing of vocal sounds and suggest parallels with human speech perception.
Animals↗
Perception of conspecific vocalizations by Japanese macaques. Evidence for selective attention and neural lateralization.
Japanese macaques (Macaca fuscata) and control species (vervet, pigtailed macaque, bonnet macaque) were trained for food to respond to one class of recorded fuscata vocalizations and do not respond to a second class. A measure of neural lateralization was obtained by presenting the stimuli randomly to the right or the left ear, and comparing performance in the two ears (ear advantage method). Vocalizations were from Steven Green's field tapes. In experiment I, the two classes were Green's 'smooth early high coos' (SE) and 'smooth late high coos' (SL). Experiment II utilized the same vocalizations, but sorted into a high-pitched and a low-pitched class, i.e., orthogonally to the communication-relevant dimension. We found that (a) Japanese macaques learned the SE-SL discrimination faster than the pitch discrimination; (b) the reverse was true for the controls; (c) Japanese macaques showed a right-ear advantage (presumed left hemisphere advantage) for the SE-SL distinction, but not for the pitch discrimination, and (d) controls (with one exception) showed no ear advantage for either discrimination. These demonstrations of selective attention to communication-relevant parameters of conspecific vocalizations, and neural lateralization in the perception of these vocalizations, parallel similar findings in human speech perception.
Animals↗
Use of Ames test in evaluation of shale oil fractions.
Conditions that affect the sensitivity of the Ames assay of complex hydrocarbon mixtures derived from shale oil were studied. Two fractions, one enriched in polynuclear aromatic compounds (PNA fraction), and a second fraction enriched in aromatic and heterocyclic amines (basic fraction), were selected for most of this work because of their comparatively high mutagenicity (i.e., compared with raw shale oil). The crude shale oil, as well as the basic, PNA, and tar fractions were mutagenic against the Salmonella typhimurium test strains, TA98 and TA100. Mutation was dependent on metabolic activation by microsomal (S9) enzymes. Both test strains responded equally well to the crude product and to the basic fraction; however, strain TA100 was more effective than TA198 in demonstrating the mutagenicity of the PNA fraction. The mutagenicity of the tar fraction could be most easily detected after metabolic activation in a liquid medium, as opposed to S9 activation in the top agar of the standard Ames assay. The mutagenicity of the basic fraction or 2-aminoanthracene was also demonstrated by metabolic activation in a liquid medium. In other set of experiments, the effect of chemical composition on the expression of mutagenicity in the standard Ames assay was estimated. Premutagens requiring metabolic activation were added to the basic and PNA fractions, and the numbers of revertants obtained in the presence of the fractions were compared with mutation induced by the compounds alone. The basic fraction did not interfere with the mutagenicity of 2-aminoanthracene and 7,9 dimethylbenz[c]acridine. Moreover, in certain experiments, the mutagenicity of the complex fraction plus the added compound was higher than expected on the basis of assays performed on these materials separately. Conversely, the PNA fraction prevented or strongly inhibited mutation by several polynuclear aroumatic compounds, and an acridine. However, the PNA fraction did not inhibit mutation induced by 2-aminoanthracene. The effect of the basic fraction on stability of the S9 enzymes in the standard Ames test was also determined.
Acridines↗
Neural lateralization of species-specific vocalizations by Japanese macaques (Macaca fuscata).
Five Japanese macaques and five other Old World monkeys were trained to discriminate among field-recorded Japanese macaque vocalizations. One task required discrimination of a communicatively relevant acoustic feature ("peak"), and a second required discrimination of an orthogonal feature of the same vocalizations ("pitch"). The Japanese animals more proficiently discriminated the peak feature when stimuli were presented to the right ear (primarily left cerebral hemisphere), as opposed to the left ear (primarily right hemisphere). In discriminating the pitch feature, the Japanese animals either showed (i) a left-ear processing advantage or (ii) no ear advantage. The comparison animals, with one exception, showed no ear advantage in processing either feature of the vocalizations. The results suggest that Japanese macaques engage left-hemisphere processors for the analysis of communicatively significant sounds that are analogous to the lateralized mechanisms used by humans listening to speech.
Animals↗