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Biomedical subjects

D Irvine

Publications and source records attributed to D Irvine.

At least 19 recordsLinked to original sources
PubMed1996

Exposure to cosmic radiation of British Airways flying crew on ultralonghaul routes.

British Airways has carried out radiation monitoring in Concorde for more than 20 years and has used a heuristic model based on data quoted by the National Aeronautics and Space Administration (NASA) to model radiation exposure in all longhaul fleets. From these data it has been calculated that no flight deck crew would exceed the control level of 6 mSv/y currently under consideration by regulatory authorities, which is three tenths of the occupational dose limit of 20 mSv/y recommended by the International Commission on Radiological Protection (ICRP). The model suggested that less than 4% of cabin crew based in Tokyo flying only between London and Japan could reach or exceed the 6 mSv/y level, based on a predicted effective dose rate of 7 microSv/h. To validate this calculation a sampling measurement programme was carried out on nine round trips flown by a Boeing 747-400 between London and Tokyo. The radiation field was measured with dosimeters used for routine personal monitoring (thermoluminescence dosimeters (TLDs) and polyallydiglycol carbonate neutron dosimeters). The limitations of the methodology are acknowledged, but the results indicate that the effective dose rate was 6 microSv/h which is consistent with the predicted effective dose rate of 7 microSv/h. This result, which is in accordance with other reported studies indicates that it is unlikely that any of the cabin crew based in Tokyo exceeded the 6 mSv/y level. In accordance with "as low as reasonably achievable" principles British Airways will continue to monitor flying crew routes and hours flown to ensure compliance.

Aerospace Medicine↗
PubMed1995

Fatigue-reducing strategies used by patients receiving treatment for cancer.

In order to determine which strategies are most effective in relieving fatigue of women undergoing treatment for cancer, women receiving either chemotherapy (n = 45) or radiation therapy (n = 54) were interviewed twice to determine their level of fatigue and the effectiveness of the strategies they used to relieve their fatigue. The subjects were interviewed either at the start and mid-point of any cycle of chemotherapy, or at the beginning and end of a 5- or 6-week course of radiation therapy. At each interview, the subjects completed the Pearson Byars Fatigue Feeling Checklist and the Fatigue Relief Scale. At the second interview, the patients were significantly more fatigued than they had been at the first interview (p < 0.0001). The more effective the fatigue-relieving strategies at the second interview, the less fatigue experienced by the women (p < 0.0001). At both interviews, subjects used similar strategies to relieve their fatigue. Sleep and exercise were among the most effective strategies. However, there was a wide range of scores for each strategy used, indicating variability among subjects as to the effectiveness of the strategy. The results of the study provide nurses with some guidance as to strategies they might suggest to patients who experience fatigue.

Adult↗
PubMed1994

The prevalence and correlates of fatigue in patients receiving treatment with chemotherapy and radiotherapy. A comparison with the fatigue experienced by healthy individuals.

Fatigue can be a prevalent and serious problem for the individual with cancer and can negatively impact on the individual's quality of life. Little is known about the prevalence of clinical fatigue among patients with cancer and how the fatigue cancer patient's experience compares with the fatigue people experience as a function of their normal daily activities. This study, which utilized a control group, investigated the prevalence of fatigue among patients receiving treatment with radiotherapy (n = 54) and chemotherapy (n =47) over two measurement points. The level of fatigue experienced by cancer patients was compared with the level of fatigue experienced by apparently healthy auxiliary staff (n = 53) working at three cancer treatment facilities. There were no differences in the mean level of fatigue experienced by cancer patients and the mean level experienced by healthy controls before the start of cancer treatment. However, cancer patients experienced a significant increase in fatigue over a 5- or 6-week course of radiotherapy and 14 days after treatment with chemotherapy, and these increases were significantly greater than the fatigue reported by healthy control subjects. The midpoint of the Pearson Byars Fatigue Feeling Checklist was accepted as a crude measure of clinical fatigue and was found to be significantly different from the mean level of fatigue reported by healthy controls. The prevalence of fatigue among patients after undergoing cancer treatment was determined to be 61%. Fatigue in cancer patients was found to covary with weight, symptom distress, mood disturbance, and alterations in usual functional activities. The best predictors of fatigue in the patient sample were their symptom distress and mood disturbance. Symptom distress and fatigue were significant predictors of impairment in functional activities related to illness. Implications for practice and future research are discussed.

Activities of Daily Living↗
PubMed1993

Irritant contact dermatitis in warehouse employees.

A detailed survey of skin complaints amongst 114 airline employees working in a new warehouse revealed 26 cases of skin problems which originated during the 2 1/2 year operation. A clinical survey of broadly the same population confirmed 14 cases from 98 employees as chronic irritant contact dermatitis of the hands. The work involved the reception, unpackaging, inspection, repackaging and dispatch of aircraft parts. The source of the skin irritation was not to be found in the work itself. Rather, the presence among the employees of two severe cases of non-occupational eczema, combined with the idea that incoming aircraft parts from foreign countries might be 'dirty' in some way, had caused a heightened perception of a risk of skin disease, and the frequency of hand washing had increased as a result. Over-frequent hand washing in a few employees had resulted in precisely what the warehouse staff had been trying to avoid.

Aircraft↗
PubMed1993

A study of thorium exposure during tungsten inert gas welding in an airline engineering population.

To investigate the theoretic possibility of excessive exposure to thorium during the process of tungsten inert gas (TIG) welding using thoriated rods we carried out a cross-sectional study of TIG welders and an age- and skill-matched group. We measured the radiation doses from inhaled thorium that was retained in the body and investigated whether any differences in health or biologic indices could have been attributable to the welding and tip-grinding process. Sixty-four TIG welders, 11 non-TIG welders, and 61 control subjects from an airline engineering population participated. All of the subjects were interviewed for biographic, occupational history and morbidity details. All of the welders and eight control subjects carried out large-volume urine sampling to recover thorium 232 and thorium 228; this group also had chest radiographs. All of the subjects had a blood sample taken to estimate liver enzymes, and they provided small-volume urine samples for the estimation of retinol-binding protein and beta 2-microglobulin. We found no excess of morbidity among the TIG or non-TIG welding groups, and the levels of retinol-binding protein and beta 2-microglobulin were the same for both groups. There was a higher aspartate aminotransferase level in the control group. The internal radiation doses were estimated at less than an annual level of intake in all cases, and considerably less if the exposure (as was the case) was assumed to be chronic over many years. Some additional precautionary measures are suggested to reduce further any potential hazard from this process.

Adult↗
PubMed1992

The mortality of British Airways pilots, 1966-1989: a proportional mortality study.

Of 446 deaths among serving and retired British Airways pilots between 1966 and 1989, 411 were analysed using the Proportional Mortality Ratio (PMR) technique. After removal of the predictable excess of aircraft accidents, excesses of cancer (PMR 1.31) and other accidents (1.60) were balanced by deficits in diseases of the circulatory (0.83) and respiratory (0.49) systems. While lung cancer was close to expectation (1.10), consistent excesses were shown in all analyses for malignant melanoma (6.68), cirrhosis of the liver (2.88), colon cancer (2.30) and brain/CNS cancer (2.68). Consideration of these ratios in relation to pilots' lifestyle and occupation leads to the conclusion that the brain/CNS cancer excess must be studied further.

Aerospace Medicine↗
PubMed1991

SELEXION. Systematic evolution of ligands by exponential enrichment with integrated optimization by non-linear analysis.

Recently, novel technologies for isolation of nucleic acid molecules with specific biological activities have been reported. In each case, the enrichment process involves repeated rounds of selection from complex mixtures of nucleic acid sequences, followed by polymerase chain reaction (PCR) amplification of ligand sequences that function in the desired manner. Particular variations in experimental conditions can dramatically alter the outcome of these processes. In this study, we use mathematical analysis and computer simulation to predict which variations have the greatest impact and to develop strategies and guidelines for enhanced effectiveness. First, we perform reconstruction tests to demonstrate that a mathematical description based on equilibrium binding is sufficient to explain the high levels of enrichment attained in the laboratory after just a few rounds. Then, we show the expected enrichment for an extensive range of conditions; and, finally, we determine the optimum protein and nucleic acid concentrations to use for maximum enrichment, while also ensuring a high likelihood of recovering even the rare molecule that binds well. The strategies and guidelines for enhanced effectiveness are generally applicable to processes for systematic enrichment of DNA, RNA or peptide ligands and have been implemented in an interactive simulation program for integrated non-linear optimization of enrichment using any target of interest.

Biological Evolution↗
PubMed1991

Psychosocial adjustment in women with breast cancer.

There is a plethora of studies investigating psychosocial adjustment in women with breast cancer, its correlates, clinical course, and prognosis. These studies have been conducted with varying degrees of methodologic rigor. An assessment has been made of the quality of this existing evidence to identify from the best evidence the factors which predict the adjustment status of women with breast cancer. Studies have been reviewed, using methodologic standards for the critical appraisal of studies on prognosis, developed by Sackett and colleagues in the Department of Clinical Epidemiology and Biostatistics at McMaster University (Hamilton, Ontario, Canada). Few of the studies investigating psychosocial adjustment of women with breast cancer meet all of the criteria for reviewing studies of clinical course and prognosis. This review focuses the direction and methodologic rigor required in future investigations. In particular, studies are needed that employ prospective designs and that deliberately measure or control for the extraneous prognostic variables that may affect adjustment. Future investigations need to incorporate adequate precision in measurement so that measures of the psychosocial variables are objective, reliable, and valid.

Adaptation, Psychological↗
PubMed1989

Soluble oil dermatitis: a follow-up study.

A pilot follow-up study of patients with soluble oil dermatitis was designed to investigate the effects on prognosis of aetiology and of stopping working with soluble oils. A questionnaire was sent to 121 machine operators who had been diagnosed over a 5-year period. Life table analysis of the 100 replies (83%) revealed a poor prognosis both for those who had continued to work with soluble oils and for those who had stopped. 78% (95% confidence intervals: 63%-94%) of those who continued to work with soluble oils had not healed 2 years after diagnosis. 70% (95% confidence intervals: 56%-83%) of those who stopped working with soluble oil had not healed 2 years after discontinuing contact. Both groups were divided into 4 subgroups with different combinations of aetiological components: allergic and endogenous, non-allergic and endogenous, allergic and non-endogenous, non-allergic and non-endogenous. No significant difference in outcome emerged in either the discontinued contact group or the continued contact group between any aetiological subgroups. Patients who discontinued contact with soluble oils fell into 2 groups: those who healed rapidly and those who developed a chronic dermatitis. 11 of the 15 patients who had healed after 2 years had done so within the first 3 months following cessation of contact. No factor could be identified to distinguish those with the more favourable prognosis. The implications of this study for the management of soluble oil dermatitis are discussed.

Adolescent↗
PubMed1984

Neurophysiological and psychological disorders and occupational exposure to organic solvents.

A number of reports, particularly from Scandinavian countries, claim that painters and workers in other trades in which prolonged occupational exposure to organic solvents may occur develop a type of mental illness characterized principally by impairment of memory and co-ordination and some deterioration of personality. The condition, called 'organic solvent disease', is recognized as a cause of premature retirement and is classed as an occupational disease in certain countries. The conclusions of these reports have been contested and the existence of such a disease entity has been questioned. The publications reporting adverse neurological, neurophysiological and psychological disorders in solvent-exposed workers, and the methods used to determine adverse effects, have therefore been evaluated. In addition, data from animal behavioural studies have been examined but were found to have little or no to have little or no relevance to the reported human disease. The human data indicate that, of the solvents studied, only CS2 provided clear evidence of neurotoxic damage detectable by clinical and pathological examination as well as by neurophysiological measurements (e.g. nerve conduction velocity and nerve action potentials) or neuropsychological techniques (e.g. Rorschach inkblot test and WAIS intelligence tests). In the case of several other solvents and mixtures of solvents commonly used in industry, the evidence of CNS impairment, based principally on the response to questionnaires and the results of neuropsychological and neurophysiological examinations was questionable. A critical evaluation of the reliability of these methods in detecting minor deviations from normal and of their ability to provide acceptable evidence of CNS dysfunction or damage leaves little doubt that these methods are of value in investigating personality, intelligence and memory in the clinical examination of individual patients. However, evidence indicates that they are not suitable for use in epidemiological studies, principally because the variability of response in normal individuals is ill-defined and insufficiently investigated. The same conclusion was arrived at in evaluating the contribution of electroencephalography, computerized axial tomography scanning and other electrophysiological examinations to the diagnosis of brain changes in groups of solvent-exposed and unexposed workers. Furthermore, the personality changes identified (by neuropsychological tests) in painters and other workers exposed to solvents could well be produced by ageing, exposure to lead or mercury, excessive alcohol intake, psychoactive drugs or the ordinary stresses of everyday life.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1984

The restoration of sensibility by nerve translocation.

A unique method is described for restoring sensibility to the completely anesthetic digits occurring as a result of irreparable segmental loss of median or ulnar nerves. Functioning proximal nerve ends are translocated into distal nonfunctional digital nerves. In all five cases presented, protective or better sensation was restored to the anesthetic digits.

Adolescent↗
PubMed1979

Visual disability and home lighting.

13 men and 43 women (average age 76) attending a low-vision clinic with visual acuity of 6/18 (Snellen) or less had acuity measurements made under standard (measured) hospital conditions, under normal home conditions, and under home conditions with augmented lighting. Median levels of ambient lighting in the home were 1/10 of those in hospital, while levels for reading were 1/7. Augmented lighting at home (a 60 watt bulb in a small adjustable lamp) improved visual acuity in 82% of subjects, restoring all but 11% to the levels achieved in hospital or above. Improvement was unrelated to disease. General levels of lighting are often so poor in the homes of elderly people that the number of people functioning as "blind" is twice what it need be. Simple improvements to lighting would reduce the prevalence of "visual disability" (less than 6/18 Snellen) from 520/100,000 home-based adults to about 300.

Aged↗