Pharmacologic properties of brewery dust extracts in vitro.

STUDY OBJECTIVES: To study the effects of extracts of brewery dust on isolated guinea pig tracheal smooth muscle in vitro. DESIGN: Parallel pharmacologic intervention on guinea pig tracheal rings that were obtained from the same animal. SETTING: Mount Sinai School of Medicine, Department of Pulmonary Medicine. MATERIAL: The isolated guinea pig tracheal tissue of 18 guinea pigs. INTERVENTIONS: Pretreatment of guinea pig rings by mediator-modifying agents before challenge with the brewery dust extracts. MEASUREMENTS AND RESULTS: The effect of brewery dust extracts on isolated guinea pig tracheal smooth muscle was studied using water-soluble extracts of dust obtained from brewery materials, including hops, barley, and brewery yeast. Dust extracts were prepared as a 1:10 (wt/vol) aqueous solution. Dose-related contractions of nonsensitized guinea pig tracheas were demonstrated using these extracts. The dust extracts contained significant quantities of bacterial components (eg, endotoxin and n-formyl-methionyl-leucyl-phenylalanine), but these agents were not thought to contribute directly to the constrictor effect of the dusts. Pharmacologic studies were performed by pretreating guinea pig tracheal tissue with the following drugs known to modulate smooth muscle contraction: atropine; indomethacin; pyrilamine; LY171883; nordihydroguaiaretic acid; captopril; thiorphan; verapamil; and TMB8. The constrictor effects of the dust extracts were inhibited by a wide variety of agents, the patterns of which depended on the dust extract. Atropine consistently and strikingly reduced the contractile effects of these extracts. These observations may suggest an interaction of the extracts with parasympathetic nerves or, more directly, with muscarinic receptors. The inhibition of contraction by the blocking of other mediators was less effective and varied with the dust extract. CONCLUSIONS: We suggest that brewery dust extracts cause a dose-related airway smooth muscle constriction by nonimmunologic mechanisms involving a variety of airway mediators and, possibly, cholinergic receptors. This effect is not dependent on presensitization of the guinea pigs.

Pharmacologic effects of cocoa and rye flour extracts on isolated guinea pig trachea.

Confectionery workers are exposed to a wide variety of organic dusts and aerosols. Previous studies with workers in a confectionery plant working with cocoa and rye flour indicate that these workers are at risk of developing adverse respiratory symptoms and lung function impairment. The effects of cocoa and rye flour extract on isolated guinea pig tracheal smooth muscle were studied using water-soluble extracts from cocoa and rye flour obtained from the studied confectionery plant. Dose-related contractions of nonsensitized guinea pig tracheal rings were demonstrated using both cocoa and rye flour extracts. Pharmacologic studies were performed by pretreating guinea pig tracheal tissue with drugs known to modulate smooth muscle contraction: atropine, indomethacin, pyrilamine, nordihydroguaiaretic acid (NDGA), acivicin, bromophenacyl bromide (BPB), 3,4,5-trimethoxybenzoate 8-(N,N-diethylamino)octyl ester (TMB8), captopril, and capsaicin. Constrictor effects of the dust extracts were inhibited by these agents, the pattern of which depended on the dust extract. Atropine consistently and significantly reduced the contractile effects of both extracts. These observations suggest a release of parasympathetic mediators by these extracts or more directly an interaction with muscarinic receptors. In addition, the constrictor effect of cocoa and rye flour extracts was significantly, but only partially, reduced by indomethacin, pyrilamine, BPB, and TMB8. Acivicin also partially decreased the constrictor effect of cocoa extract. Pretreatment of tracheal tissue with capsaicin also decreased the constrictor effects of high concentrations of cocoa and rye flour extracts. Data suggest that cocoa and rye flour extracts cause a dose-related constriction of airway smooth muscle by non immunological mechanisms involving cholinergic pathways and airway mediators such as histamine and the products of the arachadonic acid cascade. This effect is not dependent on the presensitization of guinea pigs.

Integrins inhibit angiotensin II-induced contraction in rat aortic rings.

Many extracellular matrix proteins contain the tripeptide sequence arginine-glycine-aspartate (RGD). This RGD motif is recognized by integrins, a family of adhesion receptors present on vascular smooth muscle cells. In the present study, we examined the ability of different RGD-containing peptides to affect the contraction of rat aortic rings in response to different agonists. We found that the peptide RGDS inhibited angiotensin-induced contraction in a dose dependent manner. In contrast, the peptides RGDW and RGES had no effect on angiotensin-induced contractility. We show that function-blocking antibodies to the integrins alphavbeta3 and alpha5beta1 also inhibit angiotensin-induced contraction. These effects were observed in the absence of an intact endothelium. In contrast, neither an antibody directed against the beta1 subunit nor the peptide RGDS had an effect on phenylephrine or 5-hydroxytryptamine-induced contraction. These data suggest that interactions of vascular smooth muscle with components of the surrounding extracellular matrix may influence the response of smooth muscle to agonists.

Pharmacologic characterization of latex extracts by isolated guinea pig tracheal tissue.

Latex manufacturing workers are exposed to a heterogeneous aerosol of organic compounds. Previous studies of latex workers involved in glove production indicate that these individuals are at risk of developing respiratory symptoms and impaired lung function. The effect of latex extracts on isolated guinea pig tracheal smooth muscles was studied using latex water-soluble extracts obtained at different stages of the industrial process. Latex extracts were prepared as a 1:10 (w/v) solution. Dose-related contractions of nonsensitized guinea pig trachea were demonstrated using two latex extracts (latex 1 and latex 2). Latex 1 was prepared from the native latex and latex 2 from a processed form of latex which was relatively free of soluble proteins. Pharmacologic studies were performed by pretreating guinea pig tracheal tissue with drugs known to modulate smooth muscle contraction: atropine, indomethacin, pyrilamine, nordihydroguaiacetic acid, acivicin, trimethobenzoic acid and capsaicin. Constrictor effects of the dust extracts were inhibited by a wide variety of these agents. Atropine consistently and strikingly reduced the contractile effects of these extracts. This observation may suggest an interaction of the extracts with parasympathetic nerves or more directly with muscarinic receptors. Inhibition of contraction by blocking other mediators was less effective and varied with the dust extract. Pretreatment with capsaicin did not change the constrictor effects of latex 1 but enhanced the effects of latex 2. Depletion of neuropeptides, however, did not reduce the constrictor effect. We suggest that latex extracts cause dose-related airway smooth muscle constriction by nonimmunological mechanisms involving a variety of airway mediators and possibly cholinergic receptors. This effect is not dependent on the presensitization of guinea pigs.

Effects of recycled paper dust extracts on isolated guinea pig trachea.

The effect of paper dust collected at two different locations in a paper recycling plant (PD1 and PD2) on isolated nonsensitized guinea pig tracheal smooth muscle was studied in vitro. Dust extracts were prepared as a 1:10 w/v aqueous solution. Dose-related contractions of guinea pig tracheal rings were elicited with both PD1 and PD2. Pharmacologic studies were performed with atropine (10(-6) M), indometacin (10(-6) M), pyrilamine (10(-6) M), LY171883 (10(-5) M), nordihydroguaiaretic acid (10(-5) M), and TMB8 (10(-5) M). The possible role of endogenous neuropeptides in this constrictor process was studied by depleting neural mediators with capsaicin (5 x 10(-6) M) before challenge with dust extracts. Constrictor effects were partially inhibited by a wide variety of the mediator blocking agents. The effects of both extracts were almost totally inhibited by the anticholinergic agent atropine, suggesting that a principal pathway mediating this response may involve the parasympathetic nervous system. The intracellular calcium-blocking agent TMB8 also induced a reduction of the contractile responses to PD1 and PD2 consistent with the well established role of intracellular calcium in smooth muscle constriction. Pretreatment with capsaicin significantly increased the contractile activity of paper dust extracts but only at the higher doses of these extracts. This suggests that the effect of paper dust is not initiated by the release of mediators stored in sensory nerves but that the prerelease of these mediators may enhance the constrictor effects of these dusts. We suggest that paper dust extracts cause dose-related airway smooth muscle constriction possibly associated with the release of cholinergic as well as other mediators. The constrictor effect does not require tissue presensitization or the release of neuropeptides from sensory nerves.

Respiratory function in poultry workers and pharmacologic characterization of poultry dust extract.

A group of 343 workers (252 males and 91 females) employed in four poultry farms in Croatia was studied for the prevalence of acute and chronic respiratory symptoms and lung function changes. There were significantly higher prevalences of chronic cough, chronic phlegm, chronic bronchitis, and chest tightness in poultry workers than in control workers. Male poultry workers who were smokers had significantly higher prevalences of chronic cough, chronic phlegm, and chronic bronchitis than poultry workers who were nonsmokers (P<0.01). Poultry workers exposed for more than 10 years had significantly higher symptoms prevalences than those workers with shorter exposures (except among female smokers). There was also a high prevalence in poultry workers of acute symptoms which developed during the work shift. The measured FVC, FEV1, and FEF25 in poultry workers were significantly lower than predicted normal values. Workers exposed for more than 10 years had lower ventilatory capacity tests (expressed as percentage of predicted) than those workers with shorter exposures. Changes in FEV1, FEF50, and FEF25 were less pronounced than FVC. Additionally we showed that a water-soluble poultry dust extract obtained from this workplace caused a dose-related contraction of nonsensitized guinea pig tracheal smooth muscle when studied in vitro. Pharmacologic studies of this response indicate that it may result from the release of multiple endogenous mediators. Our data suggest that work in poultry farms may, for some workers, cause the development of acute and chronic respiratory symptoms and lung function changes.

Pharmacologic characterization of wool dust extract in isolated guinea pig trachea.

Wool mill workers develop respiratory symptoms and lung function abnormalities associated with their work in the textile industry. As in other workplaces, which process organic materials, the dust generated in the manufacture of wool has been implicated as a cause of these respiratory problems. Pharmacologic studies of wool dust extract were performed in vitro on guinea pig tracheal (GPT) segments. A wool dust extract (WDE) was prepared from material collected from a mill previously surveyed. When the standardized WDE solution was added to an organ bath in increments of 10, 30, 100, 300, and 1000 microliters it caused a consistent, dose-dependent constriction of GPT. Pretreatment of guinea pig tracheas, prior to WDE challenge, with atropine (10(-6) M), pyrilamine (10(-6) M), indomethacin (10(-6) M), verapamil (10(-6) M), TMBS (10(-6) M), BW755C (10(-6) M) and LY171883 (10(-6) M) was studied in order to evaluate receptor-dependent and -independent characteristics of WDE-induced constriction. WDE-induced bronchoconstriction was partially inhibited by the antihistamine pyrilamine. Atropine and leukotriene inhibitors (LY171883 and BW755C) were not found to have a significant protective effect on WDE-induced constriction. Both TMBS and verapamil (intra- and extracellular calcium blocking agent) suppressed the effect of wool dust extract in the range tested. These findings suggest that in this model, WDE-induced airway constriction is only partly attributable to common mediators of bronchoconstriction (e.g., histamine). The airway effects of WDE may be modulated by calcium channel blocking agents.

Respiratory symptoms and ventilatory capacity in workers in a vegetable pickling and mustard production facility.

A group of 117 women occupationally exposed in a pickling factory were studied for the prevalence of acute and chronic respiratory symptoms and lung function changes. Workers were studied by task which included (1) pickling, (2) mustard making, and (3) packing. Similar prevalences for all respiratory symptoms were seen for the three workers groups, with all groups having significantly higher prevalences of chronic cough (P < 0.05), chest tightness, nasal catarrh, and sinusitis (P < 0.01) than a nonexposed control group from a bottling plant. Prevalences of acute symptoms were greater for pickling than for mustard or packing workers. Measured forced expiratory volume in 1 s and maximum flow rates at 50% and the last 25% of the control vital capacity were in general significantly lower than predicted values for the worker subgroups. Pickling workers exposed for more than 1 year in the industry had greater across-shift reductions for all spirometric parameters tested than those workers exposed for 1 year or less. Our data suggest that extended occupational exposure in the pickling industry results in acute exposure-related respiratory effects and ultimately may lead to the development of chronic respiratory symptoms and changes in baseline lung function.

Immunological findings in hemp workers.

Immunological status and its relation to respiratory findings were studied in 42 female textile workers occupationally exposed to hemp dust and in 49 female control workers. Skin prick tests with hemp or flax dust extracts from different parts of the mill in hemp workers demonstrated the following frequencies of positive tests to antigens: a mixture of hemp and flax extracts (64%), followed by flax extracts (48%), hemp from combing machines (41%), hemp from carding machines (38%), hemp from spinning and weaving machines (33%), and hemp from softening machines (20%). The prevalence of positive skin tests to hemp or flax allergens in control workers was consistently lower, ranging from 21 to 5%. Increased total serum IgE was recorded in 35.7% of hemp workers compared to only 5.0% of control workers (P < 0.05). Hemp workers with positive skin tests had significantly higher prevalences of chronic respiratory symptoms than those with negative skin tests. There were, however, no differences for acute symptoms between workers with positive and negative skin tests. Across-shift changes and baseline lung function were not different when compared by immunologic status. We showed additionally that a water-soluble extract of hemp dust causes a dose-related contraction of nonsensitized guinea pig tracheal smooth muscle when studied in vitro. Our results suggest that frequent immunologic abnormalities can be documented in hemp workers but, with the exception of chronic respiratory symptoms, in general, these do not correlate with respiratory findings.

Immunological findings and respiratory function in cotton textile workers.

Immunological parameters were studied in a group of 24 cotton textile workers. These were volunteers from a cohort of 106 (83 women and 23 men) previously studied textile workers. A group of 30 employees from a bottle packing plant served as a control for the immunologic studies. The subgroup of volunteers undergoing immunologic testing did not differ from the original cohort of textile workers in age, sex, smoking history, or prevalence of most chronic respiratory symptoms, nor were there any significant differences in baseline lung function or across-shift changes. The 24 cotton worker volunteers underwent skin testing with extracts of cotton dust and cotton seed. Eight of these 24 (33.3%) had positive tests, and 5 of the 8 had elevated serum immunoglobulin E (IgE) levels. Only one of the 8 skin-test-positive workers had symptoms of byssinosis. Only 1 of 30 control workers' skin tested with cotton extract reacted, and none had an increased serum IgE level (P less than 0.01). Both baseline lung function and across-shift changes did not differ between workers with positive and negative skin test reactions or between workers with normal and elevated IgE levels. Additionally, we studied the response in vitro of nonsensitized guinea pig trachea to cotton bract extract and demonstrated a dose-dependent contractile response. These data suggest that while immunological findings are frequent in textile workers, they correlate poorly with respiratory symptoms and function and may not be the basis for the airway obstruction seen in this disease.

Immunological and respiratory changes in animal food processing workers.

A group of 35 men employed in the processing of animal food was studied to assess the relation between respiratory findings and immunological status. The most frequent positive skin prick reactions to occupational allergens were to fish flour (82.9%), followed by carotene (77.1%), corn (65.7%), four-leaf clover (62.9%), sunflower (54.3%), chicken meat (31.4%), soy (28.6%), and yeast (22.7%). Increased total IgE serum levels were found in 14/35 (40.0%) animal food workers compared to 1/39 (2.6%) in a healthy population (p less than 0.01). A significantly higher prevalence of chronic respiratory symptoms was found among the exposed workers compared to control workers. There was however, no significant difference in the prevalence of chronic respiratory symptoms between animal food workers with positive and negative skin tests to house dust or to fish flour or among those with increased or normal IgE (except for dyspnea). The frequency of acute symptoms associated with the work shift was high among the animal food workers but similar by immunological status. There were significant mean across-shift reductions for all ventilatory capacity tests, being particularly pronounced for FEF25. Workers with positive skin tests to fish flour antigen had significantly larger across-shift reductions in FEF25 than workers with negative skin reactions. An aqueous extract of animal food dust caused a dose-related contractile response of isolated guinea pig tracheal muscle in vitro. Our data suggest that, in addition to any immunological response animal food dust may produce in vivo, it probably also causes direct irritant or pharmacological reactions on the airways as suggested by our in vitro data.

Immunological and respiratory findings in swine farmers.

The prevalence of respiratory symptoms and ventilatory capacity abnormalities in relation to immunological status was studied in 32 swine farmers and in 39 controls. A large number of swine farmers reacted to swine confinement building antigens (swine hair, 34%, swine confinement agents, 28%) but also to other extracts such as animal food (78%) and corn flour (37%). Control workers also reacted to these antigens in similar frequencies. Increased serum IgE levels were found in 3 swine farmers (9.4%) and all 3 had positive skin tests to at least one of the swine antigens. Among control workers one (2.6%) had an increased serum IgE level; this worker exhibited a positive skin reaction to swine food antigen. Swine farmers with positive skin reactions had across-shift reductions of FEF50 and FEF25 significantly larger than those with negative skin tests (P less than 0.01). Preshift measured ventilatory capacity data (FEV1, FEF50, FEF25) in swine farmers with positive skin tests were significantly lower (compared to predicted) than in those with negative skin tests. Additionally, we showed that a water-soluble swine confinement building antigen causes a dose-related contraction of nonsensitized guinea pig trachea smooth muscle studied in vitro. Our data indicate significant differences in lung function between swine workers with positive and negative skin tests. We suggest that skin testing may be helpful in identifying workers at risk for developing lung disease.