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Biomedical subjects

B T Butcher

Publications and source records attributed to B T Butcher.

At least 37 records · Page 2Linked to original sources
PubMed1986

Biochemical and immunologic characterization of cotton bract extract and its effect on in vitro cyclic AMP production. I. Field-dried bract.

Field-dried cotton bract, a contaminant of cotton dust, has been implicated in byssinosis pathogenesis. The results from this study demonstrated that a standard bract extract (FDBE) could be prepared. FDBE was antigenic in rabbits; however, precipitating antibodies were not detectable in the serum of cotton textile mill workers. Although exposure of mononuclear leukocytes (MNL) to FDBE did not alter intracellular cyclic AMP levels, it did induce changes in the cyclic AMP response of MNL to isoproterenol and prostaglandin E1. These changes were FDBE dose-dependent. The possible relationship of these findings to pathogenesis of byssinosis is discussed.

Adult↗
PubMed1986

Biochemical and immunologic characterization of cotton bract extract and its effect on in vitro cyclic AMP production. II. Green bract.

Cotton bract has been proposed as a probable byssinogenic agent. Mill workers are exposed to bract which has weathered in the field, but it is not known whether biologic effects of bract are due to intrinsic plant compound(s) or to contamination occurring during field weathering. Exposure of mononuclear leukocytes (MNL) to green bract extract (GBE) lowered basal cyclic AMP levels. Concomitant exposure of MNL to GBE plus agonist altered MNL cyclic AMP levels in a dose-dependent fashion. Differences between immunologic and pharmacologic test results of GBE and field-dried bract extract were mainly quantitative, suggesting the bioactive agent(s) in cotton bract is intrinsic to the plant.

Adult↗
PubMed1986

Cotton dust-mediated lung epithelial injury.

To determine if constituents of cotton plants might play a role in byssinosis by injuring pulmonary epithelium, we added extracts of cotton dust, green bract, and field-dried bract to human A549 and rat type II pneumocytes. Injury was measured as pneumocyte lysis and detachment, and inhibition of protein synthesis. Extracts of cotton dust and field-dried bract produced significant dose- and time-dependent lysis and detachment of both target cells, while green bract extract was less damaging. Extracts treated with polyvinylpolypyrrolidone to remove tannins produced significantly less injury. In contrast, purified 5,7,3',4'-tetrahydroxy-flavan 3,4-diol (THF), a tannin in cotton dust and bract, caused substantial cell damage. Field-dried bract extract and THF also produced dose-dependent inhibition of pneumocyte protein synthesis. Endotoxin levels did not correlate with observed injury. THF added to rat tracheal explants caused epithelial disruption and desquamation, whereas endotoxin did not. Instillation of cotton dust and field-dried bract extract in rat lungs produced disruption of bronchial epithelium and smooth muscle constriction, while polyvinylpolypyrrolidone-treated cotton dust extract produced no injury. These findings suggest that extracts of cotton plants are toxic to alveolar, tracheal, and bronchial epithelium and that THF or other tannins may be the responsible agents.

Animals↗
PubMed1986

Immunologic responses to inhaled cotton dust.

Byssinosis, a respiratory disease of workers on cotton, flax, and soft hemp, is classically characterized as shortness of breath, cough, and chest tightness on Mondays or the first day of return to work after a time off. Exposure to these vegetable dusts can also result in other respiratory diseases, and the term cotton dust-induced respiratory disease (CDIRD) is introduced. Although clinically characterized for more than a century, the underlying pathogenesis of CDIRD remains obscure. An allergic pathogenesis has been proposed. This article reviews previous and current research findings supporting this mechanism and raises the possibility that, in some individuals, CDIRD may be due to pre-existing or occupationally induced mold allergy.

Alternaria↗
PubMed1986

Absence of hyperresponsiveness to methacholine in a worker with methylene diphenyl diisocyanate (MDI)-induced asthma.

A 29-year-old man had a persuasive history of respiratory illness following exposures to methylene diphenyl diisocyanate (MDI). He was evaluated by measuring bronchial reactivity to methacholine, both before and after controlled laboratory exposures to MDI. Despite evidence of progressive declines in FEV1 with increasing (but subirritant) doses of MDI on three consecutive days, there was no bronchial hyperresponsiveness to methacholine, before or after MDI challenge. We conclude that the absence of nonspecific bronchial hyperresponsiveness does not exclude the possibility of isocyanate asthma. In the face of a compelling history, a negative result of methacholine challenge should not deter observation or laboratory testing for specific respiratory allergy to these chemicals.

Adult↗
PubMed1986

The effect of nonspecific binding by IgE on the radioallergosorbent test.

Human serum albumin (HSA), coupled to filter paper discs, was used in the radioallergosorbent test (RAST) to evaluate nonspecific binding which results from high levels of total serum IgE. Binding of 125I-labelled anti-IgE to HSA coated discs was significantly correlated with total IgE levels. A significantly better correlation was seen, however, using HSA chemically treated under alkaline conditions prior to coupling with the disc. Use of HSA as a control for individual serum samples in the RAST is discussed.

Humans↗
PubMed1985

Basidiomycete allergy: what is the best source of antigen?

Skin prick test activity and antigenicity of extracts of in vitro growth of the Basidiomycete Pleurotus ostreatus (PO) were compared to extracts of spores from PO growing in the wild. Patients demonstrated significant differences in skin test reactivity to the PO extracts. Some reacted only to in vitro growth extracts, others only to the spore extracts and 1 patient to all extracts. Further studies analyzed antigens present in all extracts with rabbit antisera to PO. Common as well as unique antigens were present in the spore extracts as compared to those from in vitro preparations. The fact that spores contain unique antigens suggests that basidiospores may be the best source of relevant allergens for clinical studies.

Antigens, Fungal↗
PubMed1984

In vitro effects of aqueous cotton dust extract on leucocyte cyclic adenosine monophosphate levels.

Aqueous cotton dust extracts (ACDE) stimulated production of cyclic adenosine monophosphate (cAMP) in normal human peripheral blood mononuclear leucocytes (MNL). This response was not due to prostaglandin production by monocytes or platelets in the cell preparation nor to stimulation of the beta-adrenergic or H2 receptors; however, desensitization experiments indicated that the response may be receptor mediated. The possible involvement of such receptor desensitization in byssinosis pathogenesis is discussed.

Adult↗
PubMed1984

Immunologic studies of hollow-fiber dialyzer extracts.

Testing failed to detect free isocyanates in dialyzer rinses or significant levels of immunoglobulin E antibodies to isocyanate-protein conjugates in the serum of individuals reacting during hemodialysis with dialyzers containing Cuprophan membranes. Extended immunization of rabbits with Limulus lysate-reactive material from dialyzer rinses demonstrated antigenic activity of the rinse that appears to originate from cotton linters used in hollow-fiber membranes. The possibility that an immunologic response to these antigens may be a mechanism in adverse reactions to hemodialysis is discussed.

Antigens↗
PubMed1983

Radioallergosorbent testing with p-tolyl monoisocyanate in toluene diisocyanate workers.

Sera from 149 occupationally exposed toluene diisocyanate (TDI) workers were tested by RAST with p-tolyl monoisocyanate human serum albumin (TMI-HSA). Of the seven positives, one had a history suggestive of TDI asthma and one had a rash which may have been TDI related. These results indicate that false positive RAST with TMI-HSA may occur in asymptomatic workers.

Asthma↗
PubMed1983

Studies on the antigenic composition of aqueous cotton dust extracts.

An immune response to cotton dust components has been proposed as a possible mechanism of byssinosis. To evaluate this possibility, specific precipitating antibodies against aqueous cotton dust extracts (ACDE) were raised in rabbits, and a reference pattern for crossed immunoelectrophoresis (CIE) was established using this extract. A significant portion of the immune response was directed against Alternaria tenuis, Aspergillus niger, and Fusarium solani, all documented contaminants of cotton dust. Preliminary crossed radio-immunoelectrophoretic studies demonstrated that some of these antigens are allergenic in man, suggesting that an IgE-mediated hypersensitivity against cotton dust, or a fungal component of the dust, may be important in byssinosis pathogenesis.

Alternaria↗
PubMed1983

Reactions during work shift among cotton mill workers.

Lung function and blood neutrophils were measured in 13 cotton mill workers on different days of the work week. Antigen was prepared from cotton dust and a radioallergosorbent (RAST) test made on serum and plasma. The exposure was determined as airborne dust and bacterial endotoxin using vertical elutriators and personal samplers. Reductions in FEV1 and increased blood neutrophils were found on Monday at an exposure level of 0.32 to 0.48 mg respirable dust/m3 and 0.19 to 0.28 micrograms endotoxin/m3. The changes in blood neutrophils correlated with endotoxin levels. The FEV1 decreases were present on Monday but not on Wednesday and Friday. The RAST ratios were low and not correlated with FEV1. No systematic changes in RAST ratios were present over the Monday shift. The results suggest that the importance of immunologic reactions other than type 1 should be investigated.

Air Pollutants↗
PubMed1983

The respiratory effects of cotton dust.

It is apparent that occupational exposure to cotton dust, and in vivo exposure to its components, may result in a number of cellular and humoral events. These include specific antibody formation, mediator release, complement activation, endotoxin effects, and related phenomena. The role of these, either singly or in combination, in the pathogenesis of cotton dust-induced lung disease awaits elucidation. Provocative inhalation challenge studies, using well-characterized standard cotton dusts with careful monitoring of physiologic effects, and in vitro assays will provide answers to some of these questions. Development of a suitable animal model would prove to be invaluable for studying the etiology of the disease and might permit evaluation of the relationship of the acute disease to any chronic effects. It is likely that several pathogenetic mechanisms may be found to be operative and that other, as yet untested, effects such as activation of arachidonic acid metabolism may play an important role in the development of this disease.

Antigens↗
PubMed1982

Development and loss of toluene diisocyanate reactivity: immunologic, pharmacologic, and provocative challenge studies.

Toluene diisocyanate (TDI) sensitivity accompanied by nonspecific bronchial hyperresponsiveness occurs in approximately 5% of occupationally exposed workers. We report the case of a 32-yr-old worker followed longitudinally after removal from isocyanate exposure. TDI reactivity was lost 11 mo after removal from exposure and nonspecific bronchial hyperresponsiveness resolved after 17 mo. Bronchial reactivity to radishes (Raphanus sativus), which developed concurrently with TDI reactivity, was lost 2 yr later. Immunopharmacologic results show that the worker's initial decreased ability of lymphocytes to produce cyclic AMP returned to near normal after 2 yr. IgE antibodies to a human serum albumin tolyl monoisocyanate conjugate were still present at this time.

Adult↗
PubMed1982

Lung function consequences of exposure and hypersensitivity in workers who process green coffee beans.

Three hundred seventy-two workers were examined at two coffee processing plants in New Orleans. Workplace dust concentrations were relatively low, and respiratory symptom prevalences were not different in various areas of the plants. After controlling for other variables, men with lengthy employment and exposure to dust of green (unroasted) coffee had lower mean residual FEV1 values (regression coefficient, -0.011 L/yr employed, p less than 0.05). Similarly, workers with serum IgE antibodies to green coffee beans had lower mean residual FEV1 (-0.244 L, p less than 0.05). Each effect remained significant after controlling for the other. In a subset that included all workers exposed to green coffee, acute changes in expiratory flow rates were not related to differences in exposure. The finding of adverse impacts of exposure and sensitization, in a work force relatively free of overt asthma, has important implications for worker health protection.

Adult↗