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Biomedical subjects

M Hutcheon

Publications and source records attributed to M Hutcheon.

12 recordsLinked to original sources
PubMed1992

Chronic lactic acidosis in a patient with acquired immunodeficiency syndrome and mitochondrial myopathy: biochemical studies.

A 30-yr-old man with acquired immunodeficiency syndrome treated with zidovudine developed biopsy-proven mitochondrial myopathy. Chronic lactic acidosis (lactate, 10 +/- 1 mmol/L) persisted for more than 5 wk. Liver function tests were normal, but the concentration of lactose rose to 16.1 mmol/L when 500 mmol of ethanol was infused. The concentration of lactose rose by only 1.5 mmol/L with maximally tolerated exercise. If this mitochondrial lesion compromised flux through the electron transport system, increased turnover of ATP with exercise should have exacerbated the degree of lactic acidosis because of increased need to regenerate ATP via glycolysis. Two possible explanations will be discussed: first, there was both a rapid rate of production of lactic acid in affected muscles in conjunction and an equally rapid rate of removal by uninvolved organs. Second, there was a low net rate of production of lactic acid in involved muscles despite the exercise.

Acidosis, Lactic↗
PubMed1987

Subjective fears and objective data: an epidemiologic study of environmental health concerns.

A political emergency arose in 1985 for the province of Alberta, Canada, because allegations of increased health risk had frightened rural Alberta residents exposed for 28 years to the airborne effluent of sour gas processing plants. In an epidemiologic study that took 3 months in the field, cross-sectional and cohort comparisons were conducted for these residents and for two carefully selected control groups. Clinical examinations were conducted with objective methods and criteria. No excess rates were found in the exposed group for any life-threatening or seriously disabling conditions. For the exposed group in the index area the reported cardinal symptoms were slightly higher than in the main unexposed reference group, but the observed cardinal signs were slightly lower. This project shows that scientifically sound strategies can be used to investigate major health controversies. Rigorous clinical methods of measurement, incorporated into a classical epidemiologic study, can inspire confidence in the studied population and can make the results acceptable to clinicians and policy makers. The studies can be done rapidly in response to urgent or crisis situations without compromising methodologic rigor or the quality of the analyses.

Air Pollution↗
PubMed1985

Longitudinal study of grain elevator and control workers with demonstration of healthy worker effect.

Changes in the respiratory symptoms and pulmonary function of 441 grain elevator workers and a control group of 180 civic workers during a three-year period were compared. The grain handlers who left their jobs during the interval between the first and second surveys were found to have shown a significantly higher prevalence of cough and shortness of breath at the beginning of the study period than those who remained employed; this difference was not observed among the civic workers. The grain and civic workers who were examined on both occasions showed similar longitudinal changes in their symptoms and pulmonary function. Nevertheless, the results of this study are biased by the healthy worker effect among the grain handlers.

Age Factors↗
PubMed1984

Pulmonary alveolar proteinosis and aluminum dust exposure.

A 44-yr-old male presented with shortness of breath, diffuse X-ray infiltrates, and physiologic evidence of a restrictive lung disease. Biopsy revealed pulmonary alveolar proteinosis. The patient had worked for the previous 6 yr as an aluminum rail grinder in a very dusty environment. Analysis of his lung tissue revealed greater than 300 X 10(6) particles of aluminum/g dry lung; all of the particles appeared as spheres of less than 1 mu diameter. We believe that this case represents an example of pulmonary alveolar proteinosis induced by inhalation of aluminum particles; this finding confirms animal studies which suggest that proteinosis can be produced by very large doses of many types of finely divided mineral dust.

Adult↗
PubMed1983

Variables of pulmonary allergy and inflammation in grain elevator workers.

The purpose of this study was to examine possible mechanisms of the obstructive and restrictive ventilatory defects of grain elevator workers. We found that grain handlers whose skin tests were positive to grain or fungal antigens had no excess of respiratory symptoms or pulmonary function abnormalities. Also, those having a possible work-related respiratory problem showed no response to inhalation challenge tests with grain dust extract. In addition, grain handlers exhibited neither an increase in positive serum precipitin tests with fungal antigens nor abnormal serum levels of C3 and C4, C-reactive protein, rheumatoid factor or antinuclear factor. However, their serum a1-antitrypsin level was elevated. The latter finding may be indicative of a pulmonary inflammatory process, but we have found no clear indication of a type 1 or 3 allergic state in grain elevator workers.

Adult↗
PubMed1982

Grain elevator workers show work-related pulmonary function changes and dose-effect relationships with dust exposure.

The purpose of this study was to determine whether grain handlers underwent work-related changes in their pulmonary function and, if so, to examine the dose-effect relationships with dust exposure. The pulmonary function of grain handlers was measured at the beginning and end of work shifts over a period of one week, during which their exposure to dust was measured daily. The results showed changes indicative of a within-day obstructive change, in addition to a small restrictive defect occurring over the course of a week. Civic outside labourers who were examined as a control group showed a similar within-week obstructive change without any associated restriction of lung volume. The data on the grain handlers were also used to examine the dose-effect relationships of dust exposure, both on baseline pulmonary function and on within-day changes in these measurements. The baseline flow rates of workers who did not wear a mask were found to vary inversely with their average exposure to respirable dust. In addition, the flow rates underwent a within-day decrease that varied directly with their corresponding exposure to respirable dust and was unrelated to mask wearing. The median of the slopes for this relationship indicated that 50% of the subjects had a decrease of at least 923 ml/s in the value of their Vmax50%VC for each 1 mg/m3 increase in the concentration of respirable dust. Non-respirable dust did not have a measurable effect either on the baseline or the within-day changes in pulmonary function. The acute changes were unaffected by age, duration of employment, or extent of smoking.

Adult↗
PubMed1980

Polyarthritis due to Mycobacterium kansasii in a patient with rheumatoid arthritis.

A case of destructive polyarthritis due to infection by Mycobacterium kansasii is described in a 68-year-old patient with long-standing rheumatoid arthritis (RA) receiving prednisone and azathioprine therapy. Superimposed infection was suggested by positive Ziehl-Neelsen stains of synovial fluid from the patient's right shoulder and wrists, with confirmation on culture. Histological examination of synovium revealed abundant noncaseating granulomata within subsynovial cellular infiltrates. Treatment with triple antituberculous chemotherapy resulted in substantial extra-articular improvement within 3 months. However, articular destruction progressed unabated. A high index of suspicion is needed to diagnose joint infections in patients with underlying polyarthritis who are receiving immunosuppressive therapy. The progressive joint damage, despite periarticular resolution, may suggest the need for a combination of surgical synovectomy and antituberculous chemotherapy.

Aged↗
PubMed1979

Comparison of respiratory variables in grain elevator workers and civic outside workers of Thunder Bay, Canada.

We compared respiratory variables in 441 grain elevator workers with 180 civic outside laborers in Thunder Bay. The grain handlers had a lower frequency of both positive skin reactions to pollens and molds and a family history of asthma, which suggests that they may have been self-selected for a decreased tendency to develop allergic respiratory disease. There was a higher frequency of cough and rales and a small decrease in forced vital capacity and forced expiratory volume in one sec among the grain handlers, as compared to the civic workers matched for smoking. However, these differences between grain and nongrain workers were small in comparison to those between smokers and nonsmokers. There was no clear indication of a worsening of respiratory functions that could be attributed specifically to duration of employment as a grain elevator worker.

Adult↗