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Biomedical subjects

D C Glass

Publications and source records attributed to D C Glass.

At least 19 recordsLinked to original sources
PubMed1995

Perceptions of control, burnout, and depressive symptomatology: a replication and extension.

In this 2-year follow-up of 100 nurses, significant increases were observed for burnout and depressive symptomatology. Analysis of change scores and structural equations suggested that the variance shared by burnout and depression (20%) may be attributable to their co-development. A definitive temporal sequence among measures of burnout and depressive affect was not obtained. At initial assessment and follow-up, burned-out nurses displayed accurate perceptions of job uncontrollability, whereas non-burned-out nurses overestimated job control. Perceptual accuracy increased in linear fashion with degree of burnout, irrespective of depressive symptomatology. Frequency of threats to job control predicted a significant amount of the variance in perceptual accuracy, supporting the view that "burnout realism" is reality driven.

Adult↗
PubMed1994

P-glycoprotein-associated Cl- currents are activated by cell swelling but do not contribute to cell volume regulation.

P-glycoprotein-associated Cl- conductance is activated by cell swelling; the ensuing Cl- efflux is thought to contribute to cell volume regulation. We tested this hypothesis in human breast cancer cells transfected with human mdr1 complementary DNA, which display P-glycoprotein-associated, swelling-activated Cl- currents. The Cl- electrochemical driving force favors Cl- efflux, but there was no appreciable Cl- loss or regulatory volume decrease (both assessed with fluorescent dyes) during the exposure to hyposmotic solution. Calculations indicate that the swelling-activated Cl- current is insufficient to cause a significant Cl- efflux. Hence, regulatory volume decrease is not a function of P-glycoprotein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Retrospective assessment of solvent exposure in paint manufacturing.

This paper describes how exposure to solvents at two large paint making sites was assessed in a study carried out to investigate the possibility of neuropsychological effects resulting from long term exposure to organic solvents. A job exposure matrix was constructed by buildings and year. A detailed plant history was taken and this was used to identify uniform exposure periods during which workers' exposure to solvents was not thought to have changed significantly. Exposure monitoring data, collected by the company before the study, was then used to characterise exposure within each uniform exposure period. Estimates were made for periods during which no air monitoring was available. Individual detailed job histories were collected for subjects and controls. The job histories were used to estimate exposure on an individual basis with the job exposure matrix. Exposure was expressed as duration, cumulative dose, and intensity of exposure. Classification of exposure by duration alone was found to result in misclassification of subjects.

Environmental Monitoring↗
PubMed1994

Investigation of dose related neurobehavioural effects in paintmakers exposed to low levels of solvents.

A cross sectional study was carried out to compare 110 paintmakers exposed to solvents with 110 age matched controls for outcome measures designed to assess cognitive performance and mental health. Hygiene data available for the paintmakers allowed the development of individual indices of solvent exposure and the analyses of health effects in relation to both duration and intensity of exposure. No effects on cognitive functioning or mental health were found in the paintmakers. For most of their period of employment the exposure of the paintmakers had been below current occupational exposure limits. The results are therefore interpreted as providing support for the view that long term exposure at or below current compliance levels does not result in damage to the central nervous system.

Cognition Disorders↗
PubMed1993

Depression, burnout, and perceptions of control in hospital nurses.

Depression, burnout, and perceived job control (PJC) were assessed in 162 nurses. Depression accounted for over 19% of the variance associated with emotional exhaustion--an index of burnout--and PJC accounted for another 6%. Factor analysis of the scales used to measure depression and burnout documented their discriminant validity. Perceptions of uncontrollability were significantly related to higher levels of depression and burnout. Structural equations modeling suggested that perceived uncontrollability is associated with burnout, which, in turn, is related to depressive affect. Against a criterion of actual job control, non-burned-out subjects overestimated their control, whereas burned-out subjects approached complete agreement with criterion. Despite evidence for a "depressive realism effect," greater perceptual accuracy was not attributable to depression among the more burned-out nurses.

Adult↗
PubMed1993

Job exposure matrices in industry.

Job exposure matrices (JEM) are designed to link information on occupation with information on exposure to specific workplace hazards. In spite of some limitations, JEM are particularly useful in large retrospective epidemiological studies. The development of JEM designed for a company or an industrial sector have a more specific field of application than JEM used in population-based studies, and can therefore be based on a more detailed classification of occupations and better exposure information. This article reviews on-going research related to the design of JEM in support of industry-based studies. The review covers design aspects related to the structure of JEM, and specially the four main axes that may produce differences on exposure characteristics: agent (exposure), job, time and place. Attention has also been given to the different sources of information on exposure, the characteristics of the exposure and the validation of exposure estimates.

Data Collection↗
PubMed1993

Standardization in the retrospective evaluation by experts of occupational exposure to organic solvents in a population-based case-control study.

Epidemiologists carrying out retrospective evaluation of occupational exposure to solvents often use experts to assist in drawing up and interpreting structured questionnaires. However the epidemiologist cannot pass complete responsibility to the expert for deciding on the relative importance of the different exposure variables. Expert assessment of exposure to organic solvents was carried out in a population-based case-control study. The process of expert evaluation was examined and the different steps in the process identified. This paper describes work in progress on the formalization of the rules that experts use to identify and quantify exposure.

Case-Control Studies↗
PubMed1992

Occupational exposure to carbon monoxide and sulphur dioxide during the manufacture of carbon black.

The manufacture of carbon black is known to generate carbon monoxide and sulphur dioxide in the 'production gas' and the pyrolysis products of the 'production gas', respectively. Adverse health effects have been reported as associated with both contaminants (coronary heart disease with carbon monoxide and respiratory morbidity with sulphur dioxide). A major cross-sectional and longitudinal respiratory morbidity study is being conducted to assess the effects of exposure to carbon black on lung function, on chest X-rays and on responses to a questionnaire. The questionnaire includes questions on respiratory and cardiovascular symptoms, so that information regarding confounding exposure is essential. The working population of 18 manufacturing plants in seven European Countries was split into 13 job title numbers (1-13) which were then amalgamated into five job categories (A-E), with an appropriate (statistically) number of samples taken from each plant-job category. In total, 1322 carbon monoxide samples and 1301 sulphur dioxide samples were taken, using actively pumped longterm colorimetric tubes. In the majority of cases, more than half of the samples in each plant-job category were either zero or trace, thereby preventing the accurate estimation of the average exposure. The highest median carbon monoxide concentration was from the amalgamated data from all 18 plants in job number 9 (furnace operators), the highest median sulphur dioxide concentration was only 'trace'. The large number of zero and trace values also precluded the generation of current and retrospective exposure indices.

Air Pollutants, Occupational↗
PubMed1992

Occupational exposure to carbon black in its manufacture.

Carbon black is manufactured by the vapour phase pyrolysis of heavy aromatic hydrocarbon feedstocks. Its manufacture is worldwide and the majority of its production is for use in the rubber industry especially tyre manufacture. Its carbonaceous nature has led many to investigate the occurrence of exposure-related medical conditions. To quantify any such relationships, it is necessary to assess exposure accurately. As part of such an epidemiological investigation survey involving the measurement both of respirable and of total inhalable carbon black was undertaken in 18 plants in seven European countries between mid-1987 and mid-1989. A total of 1298 respirable samples (SIMPEDS cyclone) and 1317 total inhalable samples (IOM head) were taken and deemed of sufficient quality for inclusion in the study. The distributions of the time-weighted average values were assessed and found to be best described by a log-normal distribution, and so exposure is characterized by geometric means and standard deviations. The data are presented in terms of 13 separate job titles for both dust fractions and shows a wide variation between job titles, with the highest mean exposure experienced by the site cleaners, and 30% of the samples taken from the warehouse packers being in excess of the relevant countries' occupational exposure limits for total inhalable dust. The quality and extent of this data allows both for comparison with exposure standards and for generation of occupational exposure indices, which will be presented in another paper (Gardiner et al., in preparation).

Carbon↗
PubMed1991

Effects of emotional imagery on physiological and facial responses in Type A and Type B individuals.

Type A behavior was examined in relation to physiologic and facial-expressive changes associated with anger, fear and distress. Affect was induced by an imagery procedure in which subjects recalled and described actual, emotion-related episodes. Type A was assessed by a structured interview. Subjects were healthy men, 21 Type As and 21 Type Bs, whose mean age was 39 yr. Type Bs showed higher systolic blood pressure responses and greater expression of negative affect than Type As. Data analysis also revealed a tendency for enhanced physiologic and facial responses of Type Bs relative to Type As to be greater during fear and distress than during anger. These results appear to reflect a coping process whereby Type A individuals show attenuated facial-expressive and physiologic reactivity as a means of maintaining a sense of control over aversive conditions.

Adult↗
PubMed1990

An assessment of the exposure of water reclamation workers to hydrogen sulphide.

The paper describes a 4-month study of water reclamation workers in a rural area. Workers were chosen randomly from each of three groups: permanent site workers, mobile workers and tanker drivers. The exposure to H2S of each of these workers was monitored with pumped long-term colorimetric tubes over 4 days. The reclamation sites were visited over the period of the study and monitored with a hand-held H2S-measuring instrument to identify sources of possible exposure. Data on the weather conditions were also collected. Routine exposure to H2S was found to be low; only 14% of exposures were above the minimum detection limit of 0.1 ppm 8-h time-weighted average (TWA). None of the 190 valid samples were above the 8-h TWA occupational exposure standard (OES) of 10 ppm. If all the exposure had occurred in a 10 min period, 6% of exposures would have been above the 10 min TWA limit. The hand-held readings and knowledge of the work pattern suggest that this was unlikely to have been the case. Most of the positive personal exposure measurements were associated with tanker drivers who were not dealing with treated sludge only. There was a statistically significant difference between the likelihood of exposure to H2S occurring in warmer, drier weather and in cooler, wetter weather. Sites and jobs which can result in transient exposure to H2S are identified.

Environmental Monitoring↗
PubMed1982

Psychological and physiological responses of individuals displaying type A behaviour.

Earlier findings on the relationship between the coronary-prone behaviour pattern Type A and coronary heart disease (CHD) are briefly reviewed, with particular reference to the underlying pathophysiological mechanisms linking the two. Results obtained during the playing of competitive games with or without harassment from the opponent suggest that competition alone does not distinguish between Type A and Type B individuals. The Type A pattern appears to be associated with exaggerated cardiovascular responses only as the result of hostile interactions. The primary need to study the Type A pattern as psychological construct is emphasized. Analysis of structured interview responses suggests that hostility and competitive drive are the two components of the pattern associated with cardiovascular disease. A model is proposed in which Type A subjects, faced with threats of their control, exhibit first hyper-responsive and then hypo-responsive efforts to regain it, and experimental evidence in support of this model is presented. However, such hyper-responsive reactions might be linked more closely to coping and defence mechanisms than they are to Type A. It is proposed that the Type A pattern be regarded as an aspect of the person-situation interaction and that efforts be made to establish those classes of environmental stimuli likely to elicit it.

Coronary Disease↗
PubMed1979

Harm-doing and victim's racial or orthopedic stigma as determinants of helping behavior.

Three experiments tested a prediction derived from an ambivalence theory of behavior toward the stigmatized. The prediction was that unintentional harm-doers would be more likely to make restitution by doing a favor for a stigmatized victim than for a nonstigmatized one. In Experiment 1 it was upheld for black versus white victims. In Experiment 2, where the victim of harm-doing was either physically handicapped or normal, the prediction was upheld only among older subjects, following the post hoc introduction of an age variable. Experiment 3 also used a physical disability variable. The data were consistent with the prediction, although the adequacy of the harm-doing manipulation was not checked empirically. On the whole, these results are seen as complementing previous findings of amplified post-harm-doing denigration of black and disabled victims. An assumption that the relationship between harm-doing and altruism was mediated by guilt arousal received only fragmentary support. That is, self-reports of guilt were highest in the harm-doing black confederate condition in Experiment 1, and self-reports of negative affect were highest in the harm-doing/wheelchair confederate condition in Experiment 3, but there were no significant relationships between individual differences in guilt or negative affect on the one hand, and amount of helping, on the other.

Adolescent↗