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Biomedical subjects

I Webster

Publications and source records attributed to I Webster.

At least 19 recordsLinked to original sources
PubMed1991

The relation between fibrosis of hilar lymph glands and the development of parenchymal silicosis.

The necropsy findings on the cardiorespiratory organs of 849 South African gold miners were analysed to test the hypothesis that fibrosis of the hilar lymph glands predisposes to the development of parenchymal silicotic nodules. Four hundred and eighty three cases had fibrosed glands, 34% of which also had parenchymal silicosis. By comparison, of 238 cases with silicosis, 88% had fibrosed glands. The proportion of cases with both silicosis and fibrosed glands, as well as those with gland fibrosis only, increased with increasing duration of exposure. As far as can be ascertained from a necropsy series such as this, it is possible that fibrosis of the lymph glands may predispose to the development of lung parenchymal silicosis.

Fibrosis↗
PubMed1987

Pathological findings in mine workers: I. Description of the PATHAUT database.

A computerized system for recording the results of structured, numerically coded autopsy reports on various types of mine workers has been in operation at the National Centre for Occupational Health in Johannesburg since 1975. Historical developments, particularly those associated with compensation for occupational disease, have resulted in very high autopsy rates, especially among whites. Since its inception, the pathology automation (PATHAUT) system has accumulated the results of more than 33,000 autopsies. The data set is described in the hope of stimulating interest in the possible uses of the data and encouraging collaborative research. Some characteristics of the database with potential research implications are discussed. These include differing age and work patterns for blacks and whites and geographic factors with potential influence on whether a body or only the cardiorespiratory organs are sent for examination.

Autopsy↗
PubMed1987

The predictors of emphysema in South African gold miners.

Environmental and host factors have been implicated in the pathogenesis of emphysema. To assess the role of gold mining exposure (an environmental factor) and of various clinical features recorded early in a miner's career (host factors), a case control study was carried out as follows. From whole lung sections made routinely at all full autopsy examinations on South African gold miners, we selected 44 cases of emphysema and 42 controls without emphysema from among men 51 to 71 yr of age who died during 1980 and 1981. Exposure information was gathered and clinical records were reviewed for smoking history, symptoms, and the presence of rhonchi by decade before death. The presence and grade of silicosis (abstracted from the routine autopsy reports) was similar in both groups; so was bronchitis in the 49 cases and controls with histologic material adequate for review. However, cases were on average older, had worked more shifts in high dust, and had smoked more than controls; they had also exhibited symptoms and rhonchi more frequently before 1950, i.e., 30 yr before death. When these factors were examined in a multiple logistic regression analysis, shifts worked in high dust, smoking, and age were all shown to be strong and independent predictors of emphysema at autopsy; prediction, however, was not improved by addition of any of the clinical features examined. These findings agree with previous cross-sectional studies in South African gold miners showing an exposure response relationship between mining service and air-flow limitation measured by lung function tests in life.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

Evaluation of general practitioners' use of a smoking intervention programme.

A study was made of a smoking cessation programme in a four-man general practice to determine the efficacy of general practitioner counselling and follow-up. In the treatment group 33% of patients became abstainers at six months compared with 3% in the control group. Self-reports of smoking status were verified by blood tests. Patients were more successful if they attended the first three visits compared with those who did not fully attend (48%: 6%). Continuing smokers had significantly higher blood concentrations of cotinine, thiocyanate and carboxyhaemoglobin per cigarette smoked at six months than at entry, despite a 30% decrease in stated cigarette consumption. This suggests that when smokers reduce the number of cigarettes smoked they compensate by increased inhalation. If general practitioners in Australia widely used the intervention programme with similar success this could have a major impact on the smoking habits of the three million smokers in Australia between 16 and 65 years of age. The total cost of the visits is a fraction of the medical treatment for a cigarette-related disease.

Adolescent↗
PubMed1983

A comparison of the effects of exposure of baboons to crocidolite and fibrous-glass dusts.

Epidemiological studies have not revealed any significant health hazards from exposure to fibrous glass and animal experiments have been inconclusive. Baboons exposed to a fibrous-glass dust cloud with size features similar to those of crocidolite asbestos developed focal peribronchiolar fibrosis with scant ferruginous body formation. The lesions were similar to those produced by crocidolite but were less extensive. No neoplasms occurred.

Animals↗
PubMed1982

Lymphocytic infiltration of pleural mesothelioma and its significance for survival.

Pleural mesothelioma is an uncommon but usually highly malignant tumour. A study has been made of 110 cases from the Mesothelioma Register of the National Centre for Occupational Health. Adequate information regarding survival was documented in 63 cases. In 5 of the latter there was insufficient tissue for accurate classification. Thirty-five patients were dead within 9 months of first presentation, and in 33 of these there was an insignificant or absent lymphoid reaction. Fifteen patients survived 18 months or more, and 10 of these had a significant lymphocytic infiltration in the original biopsies. In an intermediate group of 8 patients, who survived between 9 and 18 months, a variable lymphoid reaction occurred. We conclude that the presence of significant lymphoid infiltration indicates a better prognosis for longer survival in patients with pleural mesothelioma.

Cell Aggregation↗
PubMed1982

Immunotherapy with BCG vaccine in 30 cases of mesothelioma.

Thirty patients with malignant pleural mesothelioma who underwent BCG vaccine immunotherapy are presented. There was an improved survival rate, compared with patients treated symptomatically only. Techniques of therapy are detailed and the importance of 'tumour load' reduction and prolonged injection schedule, is stressed.

BCG Vaccine↗
PubMed1981

Attempts to demonstrate short-term metabolic effects of vinyl chloride in normal rat liver.

The present study examines whether VCM or one of its metabolites, chloracetaldehyde, has a short-term effect on cell metabolism. ATP, ADP, and AMP levels were measured in regenerating rat liver after 4 and 16 hours. No change in the levels of these nucleotides was evident after i.v. injection of VCM immediately after partial hepatectomy. A second technique, that of measuring transmembrane potentials with microelectrodes, was applied both to cells in rat liver slices and pulmonary alveolar macrophages. The addition of VCM and chloracetaldehyde with the electrodes in position in rat liver slices had no significant effect on transmembrane potentials. The same was true for a series of measurements on macrophages before and after addition of the test chemicals. It therefore appears that VCM does not alter general cell metabolism but could act on a specific intracellular target.

Adenine Nucleotides↗
PubMed1980

A survey of black mineworkers of the Cape crocidolite mines.

Between 1974-1978, a study group 970 mineworkers exposed from before July 1962 only to Cape crocidolite were traced: 755 were alive and 215 dead. Of those still alive, 66.1% showed no radiological abnormalities of the chest; 8.9% had irregular small opacities only; 17.7% had pleural abnormalities only; and 7.3% had both. Five pleural mesotheliomas were found in living ex-workers; although only one was reported in those who had died, this was considered to be an underestimate. The incidences of pleural mesotheliomas in ex-employees of the mining industry outside of the study group are also described.

Black or African American↗
PubMed1979

Lung function in an Australian population: 2. Spirometric performance and cigarette-smoking habits.

The FEV1, FVC and FEV1/FVC% in 12016 females and 18 359 males were related to cigarette-smoking habits. Over all, non-smokers had significantly better lung function than cigarette smokers. Ex-smokers of either sex had significantly higher FEV1 and FEV1/FVC% than cigarette smokers, but the FVC values were higher only in females. With consumption in excess of 10 cigarettes per day, deterioration in lung function was manifest in both sexes, but was greater in males than females. The mean chronological age of males who smoked from 30 to 50 cigarettes per day was 12.9 years and 9.6 years less than would have been predicted on the basis of their FEV1 and FVC values respectively. The corresponding values in women were 9.3 years and 7.9 years respectively. Additionally, the deterioration in lung function with increasing age was greater in cigarette smokers than in non-smokers.

Adolescent↗
PubMed1979

Lung function in an Australian population: 1. Spirometric standards for non-smoking adults.

Relationships between age, height, weight and spirometry with FEV0.5, FEV1, FVC and FEV1/FVC are described for a sample of 6275 female and 6511 male non-smoking adults living in New South Wales. Prediction equations for ventilatory function tests are derived from non-smokers and compared with other standards that are available in a population sample of 31172 subjects. It is concluded that the standards described in this paper are more appropriate for use in Australian populations. Nomograms for predicting FEV1 and FVC in females and males are provided.

Adolescent↗
PubMed1979

Risk of asbestosis in crocidolite and amosite mines in South Africa.

X-rays of all while and mixed-race men employed in crocidolite and amosite mines and mills were read independently by three experienced readers according to the ILO U/C classification. Abnormality was regarded as present if reported by two or more readers. Parenchymal abnormality, defined as the presence of small irregular opacities of profusion 1/0 or greater, was found in 7.3% of the workers. Pleural thickening was found in 4.5% of the workers, costophrenic angle obliteration in 3.2%, and pleural calcification in 1.7%. The prevalences of both pleural and parenchymal abnormality were strongly related to the duration of exposure to asbestos at work. The overall prevalence of abnormality increase from 4.0% in men with exposure for 1 year or less to 47.9% in men with more than 15 years of exposure. After taking into account the effects of age and duration of asbestos exposure, the prevalence of pleural abnormality was not predicted by fiber concentration. However, white men working with amosite tended to develop a higher prevalence of pleural abnormality than did those working with crocidolite. Compared to whites, men of mixed race, who only work with crocidolite, had a high prevalence of pleural abnormality in each exposure duration category. In contrast to pleural abnormality, the prevalence of parenchymal abnormality, after taking into account the effects of age and duration of exposure, was significantly predicted by fiber concentration but not by race or asbestos type. Our results suggest that parenchymal abnormality in workers in South African asbestos mines could be largely prevented by reducing exposure to fibers visible under the light microscope. However, this may not be the case for pleural abnormality.

Adult↗
PubMed1978

Mesothelioma in relation to asbestos fibre exposure. A review of 70 serial cases.

Seventy consecutive patients suffering form mesothelioma of the pleura were referred to the National Research Institute for Occupational Diseases. In only 1 case was it not possible to elicit a history of significant exposure to asbestos dust. An occupational and environmental history must be taken by a knowledgeable person before it is possible to conclude that there has been no asbestos exposure.

Asbestos↗
PubMed1978

Lead and morbidity: A dose-response relationship.

Many laboratory tests have been recommended for monitoring factory workers exposed to lead. To select the most useful test the best predictor of selected measures of morbidity was sought. 639 lead-exposed workers in several factories were questioned about abdominal ache, constipation, and fatigue and were examined for hand tremot. Packed-cell volume, blood-lead, urinary lead, and delta-aminolaevulinic acid were estimated in 489 workers. About half of the values for the latter three tests fell into the "excessive" or "dangerous" category of lead absorption. Blood-lead was a better predictor of morbidity than any other laboratory test, and further information did not add appreciably to morbidity prediction. The findings suggest that blood-lead measurement is the most meaningful test for monitoring workers exposed to lead. The effect of lead on morbidity does not appear to depend on its action on the porphyrin metabolic pathway.

Abdomen↗