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Biomedical subjects

I Broder

Publications and source records attributed to I Broder.

At least 37 records · Page 2Linked to original sources
PubMed1988

Comparison of health of occupants and characteristics of houses among control homes and homes insulated with urea formaldehyde foam. II. Initial health and house variables and exposure-response relationships.

A health survey was conducted on 1726 occupants of urea formaldehyde foam insulated (UFFI) houses and 720 residents of control homes. The occupants of the UFFI houses showed a modest excess of many symptoms relative to the controls. This excess of complaints was contributed mainly by the residents of households which were intending to have their UFFI removed and by onsets which followed the installation of UFFI. There were no associated abnormalities in nasal airway resistance, sense of smell, pulmonary function, or patch tests for allergy to formaldehyde. However, the UFFI subjects intending to have their UFFI removed demonstrated a small increase in nasal epithelial squamous metaplasia. The indoor formaldehyde levels of the UFFI houses were about 20% higher than in the controls, while the carbon dioxide levels were similar in both groups. The UFFI subjects showed positive relationships between level of formaldehyde exposure and the presence of a number of symptoms, which were largely dependent on a small group of formaldehyde values that were in excess of 0.12 ppm. A number of the exposure-response relationships were enhanced by UFFI. These results suggested that some adverse health effects of UFFI were explained by formaldehyde alone while others were related to the combined effects of formaldehyde and an additional UFFI-related factor(s) which was not identified.

Carbon Dioxide↗
PubMed1988

Comparison of health of occupants and characteristics of houses among control homes and homes insulated with urea formaldehyde foam. III. Health and house variables following remedial work.

This report describes the second survey of a group of 762 control and urea formaldehyde foam insulated (UFFI) houses performed following an interval of 1 year, after about two-thirds of the UFFI households either had their UFFI removed or performed other UFFI-related remedial work. The UFFI subjects who lived in remedial houses showed a decline in indicators of impaired health status, to roughly equalize with those whose houses were not altered; they continued to show a small excess of adverse health indicators relative to the controls, but at a somewhat lower level than seen in the first survey. This improvement was not associated with changes in indoor levels of formaldehyde. Weak exposure-response relationships were observed between formaldehyde and upper and lower respiratory symptoms, but mainly in the combined UFFI and control populations; these are interpreted as representing the contribution of background levels of formaldehyde to the prevalence of respiratory complaints in the general population. The principal findings of this study were primarily based on subjective variables, but most could be directly validated by objective measurements in the UFFI and control subjects. The support for a causal relationship between impaired health and living in a UFFI house is considered to be moderately strong. However the demonstrated adverse effects are generally minor in nature.

Construction Materials↗
PubMed1988

Six-month double-blind, controlled trial of high dose, concentrated beclomethasone dipropionate in the treatment of severe chronic asthma.

A six-month double-blind controlled trial compared a 2,000 microgram per day dose of beclomethasone dipropionate aerosol (BDP), with current upper level doses of 800 micrograms per day of the standard BDP, in asthmatics requiring oral corticosteroids in addition to BDP and bronchodilators. Both groups showed a significant reduction in their oral steroid requirements during the study, with a 34 percent reduction in the lower dose group and a 57 percent reduction in the high dose BDP group while maintaining good symptomatic control of asthma; there was an associated improvement in baseline serum cortisol levels. Over the same period, the pulmonary function of the lower dose group showed significant worsening relative to that of the group receiving the high dose BDP which improved. There was no increase in dysphonia or oropharyngeal candidiasis among those using the concentrated BDP. We conclude that high dose concentrated BDP appears to be a safe medication in long-term steroid-dependent asthma, and is effective in reducing dependence on the use of oral corticosteroid with associated improvement both in pulmonary and adrenal function.

Administration, Inhalation↗
PubMed1988

Phenol amplifies complement-fixing activity and induces IgG-precipitating activity in grain-dust extract.

The use of phenol as a preservative in extracts of grain dust was found to be associated with an amplification of complement-fixing activity and the appearance of IgG-precipitating activity. Both activities were absorbed by IgG, suggesting that they were due to a single material. Phenol itself neither fixed complement nor formed a precipitate with IgG. 14C-labeled phenol was incorporated into the IgG precipitating material. Both the amplification of complement-fixing activity and the appearance of IgG-precipitating activity in phenol-containing grain-dust extract were dependent on the presence of air and were inhibited by heating the extract before phenol addition. One interpretation of these results is that a component of grain-dust extract, possibly an enzyme, oxidatively modifies phenol to a form that fixes complement and precipitates IgG. The modified material demonstrates properties of a polyphenol (tannin).

Chemical Precipitation↗
PubMed1987

Safety and efficacy of long-term treatment with inhaled beclomethasone dipropionate in steroid-dependent asthma.

An open long-term trial of inhaled beclomethasone dipropionate was carried out in 32 asthmatic patients chronically dependent on systemic corticosteroids. Our objectives were to study the efficacy and safety of beclomethasone and to determine the proportion of patients in whom systemic steroids could be replaced by the new drug. All subjects had a clear history and physical findings of asthma as well as significant improvement in respiratory function after inhalation of salbutamol. Patients were followed for 4 to 8 years. Compared with a baseline period, patients receiving beclomethasone had reduced symptoms and needed less bronchodilator therapy, but their pulmonary function was unchanged. Bronchial biopsy specimens from seven patients who had been taking beclomethasone for as long as 8 years did not differ histologically from specimens from five asthmatic patients who had never taken the drug. Nine patients were able to stop taking systemic corticosteroids within 9 months, eight required them occasionally, and in eight the requirement was substantially reduced; the requirement did not change appreciably in the remaining seven. Inhaled beclomethasone is a safe and effective drug for chronic administration to asthmatic patients, and in 78% of our subjects the need for systemic steroids was substantially reduced or eliminated.

Administration, Inhalation↗
PubMed1986

Methanol extract of grain dust shows complement fixing activity and other characteristics similar to tannic acid.

We have found several similarities between tannic acid and grain dust extract prepared with methanol. Both formed a precipitate with IgG, and these interactions were inhibited by albumin. In addition, both preparations fixed complement; this activity was heat stable and was removed by prior adsorption of the preparations with hide powder. Adsorption with polyvinyl polypyrrolidone reduced the complement-fixing activity of tannic acid but not that of the methanol grain dust extract. The similarities between tannic acid and the methanol grain dust extract are consistent with the presence of a tannin or tanninlike material in grain dust.

Animals↗
PubMed1986

Animal model of grain worker's lung.

We examined the light microscopic changes in the lungs of rabbits exposed to grain dust for variable periods of time, to determine whether an animal model of grain worker's lung could be developed. Experimental animals were exposed to grain dust at a concentration of 20 mg/m3 for 7 hr/day, 5 days/week, for up to 6 months. The lungs of these rabbits demonstrated a granulomatous interstitial pneumonitis associated with exudation of mononuclear cells into the alveoli and conducting airways. These changes appeared within 5 days of the onset of exposure and reached a peak at 3 weeks but were sustained through the longest exposure interval. No abnormalities were observed in the lungs of control rabbits. These results show three points of consistency with those obtained in epidemiologic studies of grain elevator workers. First, the rapid appearance of the experimental changes suggests that the mechanism of tissue injury may not be immunologic. Second, the occurrence of the histopathologic alterations in the interstitium, alveoli, and airways corresponds with the combined restrictive and obstructive ventilatory defect described in the human epidemiologic studies. Third, the absence of lung fibrosis in rabbits exposed to dust for 6 months suggests that the pneumonitis is reversible. Thus this experimental model shows promise of helping to clarify the nature and mechanism of the adverse pulmonary effects of grain dust.

Animals↗
PubMed1985

Severity of asthma in skin test-negative and skin test-positive patients.

The standardized records of 144 asthmatic patients have been analyzed to determine whether the severity of their condition was correlated with the presence or absence of positive intradermal skin test reactions to a panel of seven allergen extracts (dust, feathers, Alternaria, Hormodendrum, mixed tree pollen, mixed grass pollen, and ragweed pollen). The skin tests were totally negative in 71 of the subjects, whereas in 73 subjects there was a strongly positive response to two or more allergens. The skin test-negative patients were older than the skin test-positive ones and had a shorter duration as well as a later onset of asthma. Also, they had lower serum-IgE levels and a lower frequency of a family history of atopic disease. Moreover, the skin test-negative group lost more time from their normal activities, required more visits to their doctor as a result of asthma, and were more frequently treated with oral corticosteroids. They additionally had greater air trapping on pulmonary function tests. However, when the groups were adjusted for the discordance in their age and duration of asthma, they tended to converge in the level of the variables that described the severity of their asthma. Thus the severity of asthma was found to be relatively similar in skin test-negative and skin test-positive patients.

Adult↗
PubMed1985

Evaluation of respiratory variables in smelter and control workers before and during a shutdown period.

Thirty-six smelter workers examined in this pilot study were found to have a higher prevalence of cough and dyspnea and lower baseline lung function than did 31 controls. They also experienced decreases in forced vital capacity (FVC) and forced expiratory volume in 1s (FEV1) over the workweek while the controls did not. Baseline airflow rates and change in FVC and FEV1 over the workweek varied with levels of sulfur dioxide and particulates. Twenty-three smelter workers and 21 controls were seen on a second occasion, six months into an extended shutdown. The smelter workers continued to have a higher prevalence of cough and dyspnea and lower baseline lung function than the controls. There was, however, a slight increase in lung function in both the exposed workers and the controls during the shutdown. The results suggest that smelter workers may develop both acute and chronic work-related pulmonary effects and that the chronic effects may be nonreversible.

Adult↗
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

Respiratory variables and exposure-effect relationships in isocyanate-exposed workers.

Respiratory variables in 95 isocyanate workers and 37 control workers were compared. The exposed workers had a slightly higher frequency of cough and shortness of breath than the controls and a significantly lower frequency of family history of asthma, hay fever, and bronchitis. The isocyanate workers had slightly lower baseline lung function than the control workers but demonstrated significantly larger declines in their pulmonary function over the work shift. Both groups showed some intraday and intraweek variation in lung function. The changes in lung function over the work shift varied with different job categories, the largest changes occurring in finishing-area workers. A gradation of response was observed when exposure was categorized as nil, low, or high, but no exposure-effect relationships could be demonstrated by regression analysis of either area or personal results.

Adult↗
PubMed1984

Changes in respiratory variables of grain handlers and civic workers during their initial months of employment.

The health effects of employment as a grain handler were studied by examining workers on two occasions, firstly, immediately before or soon after they were hired and again about two and a half months after they were employed. Over this time there was a substantial increase in the prevalence of cough, sputum, and eye irritation, accompanied by small pulmonary function changes suggestive of a restrictive ventilatory defect. No comparable changes in symptoms were observed over a similar number of months in grain handlers employed for an average of nine years or in control workers consisting of newly hired or long term civic outside labourers. The long term grain handlers, however, developed a similar change in their pulmonary function. These findings indicate the occurrence of a change in the health of grain elevator workers after a relatively brief duration of employment.

Adolescent↗
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↗
PubMed1983

Time course of morphometric changes after acute allergic bronchoconstriction in the guinea pig.

Experimental allergic bronchoconstriction was induced in guinea pigs by passive sensitization with a standard dose of homologous antiserum followed by challenge with aerosolized antigen. Lungs were removed from animals at intervals of up to 6 days thereafter, and several parameters of the reaction were assessed morphometrically by comparison with lungs from unsensitized guinea pigs. We determined all changes in volume of the lung tissue resulting from fixation through to the preparation of histologic sections, but no significant differences were observed between the time course subgroups. The size of both large and small airways was assessed by a point-counting technique, as well as by measurement of the percentage of the diameter of the airways contributed by the mean thickness of the muscular layer. Maximal bronchoconstriction was observed morphometrically to correspond with the peak of a response as determined clinically by the use of a strain gauge around the chest. This was followed by a return to normal of the airway size. The number of mast cells and eosinophils around large and small airways, around branches of the pulmonary artery and in random fields of the lung parenchyma was tabulated. The maximal decrease in mast cells was seen in animals which died immediately following challenge, but the numbers were not restored to the control level even in animals which had survived for 6 days. The greatest increase in eosinophil response occurred in lungs obtained 10 min following challenge. This model will be of value in determining the effects at the tissue level of pharmacological inhibitors of this reaction.

Acute Disease↗
PubMed1983

A systematic controlled study of pulmonary abnormalities in rheumatoid arthritis.

We have conducted a prospective comparison of 155 rheumatoid patients and 95 control subjects. Both groups were selected without regard to respiratory status, but were comparable in age, sex and smoking experience. The prevalence of respiratory symptoms, of past respiratory illnesses and of pulmonary function findings of airway obstruction was similar in both groups. However, the rheumatoids showed an increased frequency of chest crackles and abnormal chest radiographs, and had pulmonary function changes suggestive of a restrictive ventilatory defect. These pulmonary abnormalities were associated with smoking, the presence of nonpulmonary extraarticular features, the level of rheumatoid disease activity and treatment with oral corticosteroid or gold.

Adult↗
PubMed1982

Tartrazine and benzoate challenge and dietary avoidance in chronic asthma.

This study undertook to determine the usefulness of tartrazine and benzoate challenge and dietary avoidance in the management of patients with chronic asthma. Double-blind ingestion-challenge tests were performed on separate days with lactose, tartrazine, benzoate and acetylsalicyclic acid (ASA). Of the twenty-eight subjects challenged, one responded to tartrazine and one to benzoate. Two additional subjects responded to ASA and a further eight were not tested with this material because of a definite history of sensitivity. Twenty-four subjects completed 1 month periods of observation while first on a normal diet and then while on a tartrazine-benzoate avoidance diet. No improvement occurred during the modified diet in anyone with positive challenge-tests or in all, but one, of those with a history of ASA idiosyncrasy; paradoxically, several of these subjects worsened during this period. We conclude that tartrazine-benzoate dietary avoidance was not of value in the management of the chronic asthmatic in this study, even among patients who respond to challenge with these substances or have ASA idiosyncrasy.

Adrenal Cortex Hormones↗
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↗