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Biomedical subjects

S Vedal

Publications and source records attributed to S Vedal.

At least 55 records · Page 3Linked to original sources
PubMed1988

Hyperinflation in asthma and emphysema. Assessment by pulmonary function testing and computed tomography.

To assess the role of emphysema on the hyperinflation in chronic asthma, we studied 20 subjects with irreversible airflow limitation. Ten of the subjects had asthma and had never smoked; the other ten were cigarette smokers. Pulmonary function testing and chest computed tomography (CT) scans were performed on all subjects. Emphysema was graded using a score based on the percentage of lung involved on CT scan. There was good inter- and intra-observer agreement for the emphysema scores. The median emphysema score was 0 percent in the nonsmoking group and 10 percent in the smoking group. All smokers with a total lung capacity (TLC) of greater than 120 percent predicted had evidence of emphysema on the CT scan. None of the asthmatic subjects with a TLC greater than 120 percent predicted had emphysema identifiable on CT scan. We conclude that chronic asthma with severe hyperinflation does not result in emphysema.

Adult↗
PubMed1988

Fate of grainhandlers with bronchial hyperreactivity.

Bronchial reactivity to methacholine and to grain dust were determined in a group of grainhandlers whose spirometry was being studied prospectively. Six workers showed specific bronchial responses to grain dust (indicative of occupational asthma), 21 did not show reactivity to grain dust but had bronchial hyperreactivity to methacholine and 40 had neither. Those with hyperreactivity were older, had lower FEV1 at initial examination and were more likely to experience a significant decline in FEV1 over a single working shift. Over 6 years of follow-up, those with hyperreactivity were not more likely to leave work and although they showed a more rapid decline in lung function over the period, because of the small number of individuals studied the difference between those with and without bronchial hyperreactivity was not significant. Among those with hyperreactivity to methacholine, there was a significant positive association between change in FEV1 over a single workshift and change in FEV1 over six years of followup, not seen in those without hyperreactivity to methacholine. Moreover, reactivity to methacholine was a stable observation over 6 years in the majority of studied individuals. We conclude that in the presence of bronchial hyperreactivity to methacholine, change in FEV1 over a single workshift more precisely predicts the trend in FEV1 over time in grainhandlers.

Adult↗
PubMed1987

Usual interstitial pneumonia: correlation of CT with clinical, functional, and radiologic findings.

Correlation between disease extent on computed tomographic (CT) scans and severity of clinical and functional impairment was obtained in 23 patients with usual interstitial pneumonia (UIP) by review of the clinical data, pulmonary function tests, chest radiographs, and CT scans. The CT scans and chest radiographs were each read twice by two independent observers. Disease extent was assessed on CT scans by a visual score (0%-100% involvement of the lung parenchyma) and on the radiograph by the International Labour Office classification. There was good intraobserver and interobserver agreement for both CT and radiograph scores (all r greater than or equal to .71). CT scans gave a better estimate of disease extent and showed more extensive honeycombing than did the radiograph. A significant correlation was found between the extent of disease as assessed with CT and the severity of dyspnea (r = .62, P less than .001), as well as between CT and impairment in gas exchange as assessed by the diffusing capacity (r = .64, P less than .001). There was poor correlation between disease severity as assessed with chest radiography and the clinical and functional variables (all r less than or equal to .39).

Adult↗
PubMed1987

Disease activity in idiopathic pulmonary fibrosis: CT and pathologic correlation.

Computed tomography (CT) scans were compared with pathologic determinants of disease activity in 12 patients with idiopathic pulmonary fibrosis. The theory was that intraalveolar and interstitial cellularity would result in areas of opacification of air spaces on CT scans. All patients underwent open lung biopsy, and disease activity was assessed with a pathologic grading system. Seven patients had mild disease activity, five had moderate to marked disease activity. Opacification of air spaces was patchy in distribution, predominantly peripheral, and seen better on 1.5-mm rather than 10-mm collimation scans. Disease activity on CT scans was graded independently from 0 to 3 based on the presence and relative density of the areas of air space consolidation compared with the surrounding parenchyma. The pathologic score was significantly greater in the patients with high CT scores than in those with low CT scores (P = .001). Five patients with marked disease activity and five of seven patients with mild disease activity were correctly identified. CT may be useful in the assessment of disease activity in idiopathic pulmonary fibrosis.

Adult↗
PubMed1987

Asthma, asthmalike symptoms, chronic bronchitis, and the degree of bronchial hyperresponsiveness in epidemiologic surveys.

Measurement of bronchial hyperresponsiveness has been suggested to be a useful test in identifying subjects with asthma in epidemiologic groups. We explored the association between the degree of bronchial hyperresponsiveness, respiratory symptoms suggestive of asthma, chronic bronchitis, and various definitions of asthma based upon information obtained from a questionnaire. We determined bronchial hyperresponsiveness by methacholine inhalation test, administered a standardized respiratory questionnaire, and performed spirometry on 1,392 male workers in various industries: 229 (16.5%) had PC20 less than 8 mg/ml, 66 (4.7%) had PC20 less than 2 mg/ml, and 8 (0.6%) had PC20 less than 0.5 mg/ml. Only 760 workers had no respiratory symptoms; no workers with PC20 less than or equal to 0.5 mg/ml, 31.0% of workers with PC20 greater than 0.5 but less than or equal to 2 mg/ml, and 38.0% of workers with PC20 greater than 2 but less than or equal to 8 mg/ml had no chest symptoms. Those reporting wheeze or breathlessness, and especially those with both symptoms, were significantly more likely to have bronchial hyperresponsiveness with a low PC20. The reporting of chest tightness did not influence this relationship, and there was no difference between the occurrence of "wheeze without a cold" and "persistent wheeze." Although there was a stronger association of PC20 less than or equal to 2 mg/ml with asthma than with chronic bronchitis, the association of PC20 greater than 2 and less than or equal to 8 mg/ml was not different with asthma than with chronic bronchitis. Bronchial hyperresponsiveness was more closely associated with asthma than with any asthmalike symptoms ascertained by a questionnaire developed for the study of chronic bronchitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma↗
PubMed1987

Daily air pollution effects on children's respiratory symptoms and peak expiratory flow.

To identify acute respiratory health effects associated with air pollution due to coal combustion, a subgroup of elementary school-aged children was selected from a large cross-sectional study and followed daily for eight months. Children were selected to obtain three equal-sized groups: one without respiratory symptoms, one with symptoms of persistent wheeze, and one with cough or phlegm production but without persistent wheeze. Parents completed a daily diary of symptoms from which illness constellations of upper respiratory illness (URI) and lower respiratory illness (LRI) and the symptom of wheeze were derived. Peak expiratory flow rate (PEFR) was measured daily for nine consecutive weeks during the eight-month study period. Maximum hourly concentrations of sulfur dioxide, nitrogen dioxide, ozone, and coefficient of haze for each 24-hour period, as well as minimum hourly temperature, were correlated with daily URI, LRI, wheeze, and PEFR using multiple regression models adjusting for illness occurrence or level of PEFR on the immediately preceding day. Respiratory illness on the preceding day was the most important predictor of current illness. A drop in temperature was associated with increased URI and LRI but not with increased wheeze or with a decrease in level of PEFR. No air pollutant was strongly associated with respiratory illness or with level of PEFR, either in the group of children as a whole, or in either of the symptomatic subgroups; the pollutant concentrations observed, however, were uniformly lower than current ambient air quality standards. Moreover, since exposure estimation based on monitoring of ambient air likely results in misclassification of the true exposure, the negative findings of this study must be interpreted cautiously.

Air Pollutants↗
PubMed1986

Plicatic acid-specific IgE and nonspecific bronchial hyperresponsiveness in western red-cedar workers.

In a cross-sectional survey of 652 workers in a western red-cedar sawmill, we obtained data on symptoms, pulmonary function, immediate skin reactivity to common allergens, nonspecific bronchial responsiveness, total IgE level, and sensitization to plicatic acid conjugated with human serum albumin as measured by RAST. Dust exposure was estimated by personal and area sampling for total dust during a work shift and cumulative exposure by duration of employment. Seven percent of the workers had an elevated RAST, and 20% had nonspecific bronchial hyperresponsiveness. Elevation in RAST was associated with bronchial hyperresponsiveness. Almost half (46%) of the workers with RAST elevation had bronchial hyperresponsiveness compared to 18% in workers with no RAST elevation. The association was unaffected by total IgE level or by limiting the analysis to workers without respiratory symptoms and was most apparent in younger workers. Bronchial hyperresponsiveness was associated with increased prevalence of respiratory symptoms as well as with lower levels of pulmonary function. The likelihood of bronchial hyperresponsiveness increased with increasing age but was unrelated to the dust-exposure concentration. RAST elevation was unrelated to employment duration or dust exposure and was not associated with an increased prevalence of symptoms or lower levels of pulmonary function independent of bronchial hyperresponsiveness. We conclude that plicatic acid-specific IgE and nonspecific bronchial hyperresponsiveness are associated in western red-cedar workers and that this association may reflect a causal connection.

Adult↗
PubMed1986

CT in silicosis: correlation with plain films and pulmonary function tests.

To investigate the usefulness of computed tomography (CT) in the qualitative and quantitative assessment of silicosis, CT scans, chest radiographs, and pulmonary function tests were obtained in 17 patients with silicosis and six controls. CT scans were graded for extent of silicosis visually and using mean attenuation values. The extent of associated emphysema was also determined. Extent of silicosis as assessed by CT was compared with extent estimated from the chest radiographs using the ILO 1980 classification and pulmonary function tests. Significant correlation was found between both the mean attenuation values (r greater than 0.62, p less than 0.001) and the visual CT scores (r greater than 0.84, p less than 0.001) compared with the ILO category of profusion. There was good inter- and intraobserver correlation for the visual CT grades of silicosis (r greater than 0.93, p less than 0.001). There was poor correlation between the pulmonary function tests and the nodular profusion on the chest radiograph and CT (r less than 0.50). Correlation was significant, however, between the CT emphysema score and both the FEV1% predicted (r greater than 0.66, p less than 0.001) and the diffusing capacity (r greater than 0.71, p less than 0.001). Using chest film assessment of the extent of silicosis, visual CT quantitation of silicosis is accurate and reproducible. Attenuation values were less reliable and their use is not recommended as an independent assessment of disease severity. The reduced levels of lung function in these patients correlated with superimposed emphysema rather than the nodular profusion. Emphysema associated with silicosis was easily detected on CT but not on the radiograph.

Adult↗
PubMed1985

Does a family history of allergy predict immediate skin test reactivity?

The value of a family history of allergy in predicting atopy was assessed in men employed in lumber mills, grain handling and railway industries in British Columbia. Detailed family and personal histories of allergy were available for 1434 men, 1426 of whom underwent prick skin testing with two common environmental allergens and one control solution. Those with a family history of allergy had 2.06 times the odds of immediate skin test reactivity as those without a family history and 1.65 (p less than 0.01) times the odds after adjustment for personal history and age. The odds of skin test reactivity in workers with a personal history of allergy were 4.76 times those of workers without such a history and 4.34 after adjustment for family history and age. Almost half (47%) of the workers with both a family and a personal history of allergy had positive results of skin testing, compared with only 10% of the workers without either history. It was therefore concluded that a family history of allergy is an independent predictor of atopy.

Adolescent↗
PubMed1985

Lymphocyte sub-populations in patients with allergic and non-allergic asthma.

The subpopulations of peripheral blood lymphocytes were identified using monoclonal antibodies specific for T lymphocytes (T11 antibodies), B lymphocytes (B1 antibodies), helper/inducer T cells (T4 antibodies) and suppressor/cytotoxic cells (T8 antibodies). Ninety-six subjects, including twenty-five patients with allergic asthma, nineteen patients with non-allergic asthma and fifty-two controls without asthma, were studied. There was no significant difference in the lymphocyte subsets between the allergic and non-allergic asthmatics. When comparing patients with asthma as a group with the controls, a decrease in the number of T8-positive suppressor cells and therefore, an increase in the helper/suppressor cell ratio were demonstrated in the asthmatics. A relative deficiency of suppressor T cells may represent another immunological marker of bronchial asthma.

Adult↗
PubMed1985

Rapid decline in FEV1 in grain handlers. Relation to level of dust exposure.

We have prospectively studied the respiratory health of a cohort of grain elevator workers in the Canadian west coast terminal elevators, beginning in 1975 and following them for 6 yr. We have used a "nested" case-control model to identify determinants of the worst trend in FEV1 over this period. The 10% of participants in this category had a mean decline of greater than 100 ml/yr. They were significantly more likely to have had a decline in FEV1 over a work week and to have nonspecific bronchial hyperreactivity. There was a significant relationship between the odds ratio of being a case and the mean level of dust exposure associated with the job and location at the work site; cases were associated with mean total dust levels greater than 5 mg/m3. We found no relationship between the odds ratio of being a case and a number of host factors, such as immediate skin reactivity to common allergens, history of asthma, bronchitis, or hay fever, or presence of respiratory symptoms. We conclude that exposure to grain dust at levels greater than 5 mg/m3 is associated with a serious adverse trend in FEV1.

Adult↗
PubMed1985

Predictors of bronchial hyperexcitability in grainhandlers.

We have studied bronchial hyperexcitability to methacholine (defined as a fall of at least 20 percent in FEV1 at 8 mg/ml or lower) in 504 white male grainhandlers working in terminal elevators in the Port of Vancouver. There was a significant association between bronchial hyperexcitability and level of FEV1; for a 10 percent decrease in percent of predicted FEV1, bronchial hyperexcitability was twice as common. Among those with bronchial hyperexcitability, the PC20 was significantly related to the FEV1. Grainhandlers with immediate skin reactivity to common allergens were twice as likely to have bronchial hyperexcitability. There was a significant increase in the prevalence of bronchial hyperexcitability with increasing duration of employment. Grainhandlers with chest tightness and breathlessness were over twice as likely to have bronchial hyperexcitability. We did not observe an increased prevalence of bronchial hyperexcitability in smokers, and there was no difference between age groups. We conclude that the determinants of bronchial hyperexcitability in this population include baseline FEV1, immediate skin reactivity to common allergens, some respiratory symptoms, and cumulative exposure to grain dust.

Adult↗
PubMed1984

Risk factors for childhood respiratory disease. Analysis of pulmonary function.

Four thousand elementary-school-age children from a rural area of western Pennsylvania participated in a cross-sectional survey that consisted of a standardized respiratory questionnaire completed by their parents and spirometric testing at school. Spirographic tracings were digitized to obtain the FVC, FEV0.75, FEF25-75, Vmax75, and Vmax90, which were standardized for height, age, and sex for the subsequent analyses. Independent associations of potential risk factors with the standardized pulmonary function measures were evaluated with multiple regression techniques. Asthma, persistent wheeze, and parental smoking habits, especially those of the mothers, were associated with lower flow rates. The effect of parental smoking was primarily due to smoking by the mother and was stronger in girls. In female children of currently smoking mothers, FEF25-75 was 96% of predicted, Vmax75 was 95% of predicted, and Vmax90 was 92% of predicted; each flow measure was 98% of predicted in male children of smoking mothers. Prolonged hospitalization at birth was independently associated with lower FEV0.75 and flow rates. Low socioeconomic status was associated with lower FVC and FEV0.75. Neither current gas stove use nor a history of severe chest illness before 2 yr of age were independently associated with lower levels of pulmonary function.

Adolescent↗
PubMed1984

Symptoms, pulmonary function, and bronchial hyperreactivity in western red cedar workers compared with those in office workers.

An epidemiologic health study was carried out on 652 cedar mill workers and a control group of 440 male office workers not exposed to air contaminants. Participants completed a medical-occupational questionnaire with trained interviewers, had allergy skin tests, performed spirometry, and had bronchial reactivity assessed by methacholine inhalation testing. After adjusting for differences in age, race, and smoking, cedar workers were found to have significantly higher prevalences of cough, phlegm, and dyspnea than did office workers. Symptoms of asthma and work-related asthma, but not persistent wheeze or doctor-diagnosed asthma, were reported in a significantly higher proportion of cedar workers than of office workers. Cedar workers also had significantly lower lung function test results than did office workers after controlling for height, age, race, and smoking. Bronchial hyperreactivity, defined by a methacholine PC20 less than 8 mg/ml, was more prevalent among cedar workers than among office workers, with the increase being limited to the nonatopic subgroup of workers. The prevalence of bronchial hyperreactivity increased with duration of employment among cedar workers but not among office workers. We conclude that exposure to western red cedar dust is harmful to the respiratory health of the workers, causing asthma and other respiratory symptoms, bronchial hyperreactivity, and lower levels of lung function.

Adult↗
PubMedDate not supplied

Exposure of chronic obstructive pulmonary disease patients to particles: respiratory and cardiovascular health effects.

To examine hypotheses regarding air pollution health effects, we conducted an exploratory study to evaluate relationships between personal and ambient concentrations of particles with measures of cardiopulmonary health in a sample of patients with chronic obstructive pulmonary disease (COPD). Sixteen currently non-smoking COPD patients (mean age=74) residing in Vancouver were equipped with a particle (PM(2.5)) monitor for seven 24-h periods. Subjects underwent ambulatory heart monitoring, had their lung function and blood pressure (BP) measured, and recorded symptoms and medication use. Ambient PM(2.5), PM(10), sulfate, and gaseous pollutant concentrations were monitored at five sites within the study area. Although no associations between air pollution and lung function were statistically significant, an estimated effect of 3% and 1% declines in daily FEV(1) change (DeltaFEV(1)) for each 10 microg/m(3) increase in ambient PM(10) and PM(2.5), respectively, was observed. Increases of 1 microg/m(3) in personal or ambient sulfate were associated with 1.0% and 0.3% declines in DeltaFEV(1), respectively. Weak associations were observed between particle concentrations and increased supraventricular ectopic heartbeats and with decreased systolic BP. No consistent associations were observed between any particle metric and diastolic BP, heart rate, or heart rate variability (r-MSSD or SDNN), symptom severity, or bronchodilator use. Of the pollutants measured, ambient PM(10) was most consistently associated with health parameters; the use of personal exposures did not improve the strength of any associations or lead to increased effect estimates.

Aged↗