Role of histamine in the aetiology of byssinosis. I Blood histamine concentrations in workers exposed to cotton and flax dusts.

The formation or the accumulation, or both, of histamine in the lungs may be potentiated by agent(s) present in cotton dust at higher level(s) than in flax dust and negligible in cottonseed dust. It has been suggested that such potentiation may be due to the activation of the ability of the lung to produce histamine and/or produce or recruit mast cells; this may present an acceptable explanation of the mechanism by which the propagation of the chronic effect of the dust proceeds in cotton and flax workers. Histamine accumulated in the lung over the weekend is released on exposure to dust causing the symptoms of byssinosis. The difference in the rate of histamine metabolism relative to the rate of histamine formation in byssinotic subjects leads to a more prolonged histamine accumulation than in symptom free subjects, with the consequent appearance of the symptoms of byssinosis. Continuous exposure to dust, without weekend interruption, leads to equivalent rates of histamine formation and metabolism with non-considerable histamine accumulation in the lungs and consequent absence of the symptoms of byssinosis.     

Role of histamine in the aetiology of byssinosis. II. Lung histamine concentrations in guinea pigs chronically exposed to cotton and flax dusts.

Data presented in this study support the finding that cotton and flax dusts contain agents which potentiate the formation or accumulation of histamine or both in the lungs of guinea pigs exposed to dust, and that such agents are present at much higher levels in cotton dust than in flax dust. The potentiating effect may be through the recruitment of mast cells into the lung. Both cotton and flax dusts contain methylating enzyme inhibitory agents, whereas cotton dust also contains agents that inhibit histaminase activity; flax dust contains agents potentiating histamine activity. These agents working together result in the accumulation or depletion of histamine observed in the different groups of animals exposed to either cotton or flax dust in this study.     

Blood histamine levels in cotton-dust exposed workers in a textile mill of Ahmedabad

Blood histamine levels were measured by the bioassay of histamine (on an isolated strip of guinea pig ileum) in workers exposed to cotton dust in a textile mill in Ahmedabad. Byssinotic subjects showed very high levels of blood histamine as compared to nonbyssinotic and control subjects. The blood histamine levels were not well correlated to the dust concentrations or duration of exposure but rather to the day of the week (ie, first, second, third, etc., after weekend break) on which the samples were collected. The blood histamine levels were high on the first day of the work week, when byssinotics complained most of their symptoms.     

Some Pharmacological Actions of Cotton Dust and Other Vegetable Dusts

Aqueous extracts of cotton and other vegetable dusts cause contraction of the isolated ileum and tracheal muscle of the guinea-pig, and of isolated human bronchial muscle. The levels of this contractor activity place the dusts of cotton, flax, and jute in the order of the probable incidence of byssinosis occurring in the mills spinning these fibres.

Extracts of cotton dust possess a histamine-liberating activity and contain a permeability-increasing component. These actions are of plant origin and are found in the pericarp and bracts of the cotton boll. Histamine and 5-hydroxytryptamine have also been found in some cotton dust samples. The formation of histamine by bacterial action in cotton dust does not take place under conditions found in cotton mills. The smooth muscle contractor substance is organic in nature, relatively heat-stable, and dialysable. The relevance of these results to the symptoms of byssinosis is discussed.

     

Histamine-related reactions in patients with byssinosis

The purpose of the study was to analyze the mechanism of histamine action in histamine-dependent reactions of neutrophils and lymphocytes in patients with byssinosis and chronic asthmatic bronchitis under cotton and flax dust effect. The appraisal of histamine content in blood serum, receptor/histamine distribution of lymphocyte and neutrophil subpopulations (rosette-forming double and triple reactions), determination of histamine modeling effect on lymphocyte-neutrophil cooperation in the inhibition reaction of leukocyte migration revealed that under cotton dust effect neutrophils and the complement system were involved into the histamine liberation process in byssinosis patients, lymphocytes were most likely not involved into the process. Flax dust-affected histamine reactions were not so distinct: lymphocyte and neutrophil reactivity in byssinosis patients did not exceed the standards. Patients with chronic asthmatic bronchitis had high blood concentration of histamine and experienced some changes in cells' migration characteristics. It was assumed that primarily nonimmune mechanisms of histamine liberation and activation of the complement system were involved into byssinosis pathological process in patients exposed to cotton and flax dust effect. In patients with chronic asthmatic bronchitis there occurred all 3 activation mechanisms of biologically active substances, i.e., allergic and nonantigenic ways of histamine liberation and activation of the complement system.     

BYSSINOSIS IN COTTON GINNERIES IN GREECE

The prevalence of byssinosis in a sample of cotton ginnery workers in Greece was investigated. The respiratory symptoms, F.E.V._1·0, and V.C. of 70 male ginnery workers were recorded. No case of clinical byssinosis was found, but a statistically significant relationship exists between years of exposure to cotton dust and impairment of lung function. On the contrary no significant relationship exists between smoking and lung function, or between sputum production and lung function. The findings suggest the hypothesis that the cotton dust may exert, in the case of a prolonged exposure, a chronic deleterious action without producing the typical symptoms of clinical byssinosis.     

Additive effect of smoking and cotton dust exposure on respiratory symptoms and pulmonary function of cotton textile workers

One hundred and sixty-nine and 175 cotton textile workers (CTWs) were enrolled in the first (1991) and second (1996) surveys to investigate the prevalence of byssinosis. The synergistic effect of smoking on cotton dust exposure was also evaluated. Although the difference in prevalence of abnormal pulmonary function between the first (38.5%) and second study (38.9%) was not statistically significant, smokers had significantly higher frequency than nonsmokers in both surveys. A significant trend existed between the cotton dust levels and the frequency of abnormal lung function. The significant trend was also noted in both smokers and nonsmokers. The frequency of respiratory symptoms and the prevalence of severe byssinosis in the second survey (14.9% and 12.6%, respectively) were significantly lower than that in the first survey (39.7% and 21.9%, respectively). The reduction of symptoms was due to remodeling of this old cotton mill. The prevalences of respiratory symptoms and byssinosis in smokers being significantly higher than in nonsmokers only found in the first survey, but not found in the second survey. These results indicate that smoking potentiates the effect of cotton dust exposure on respiratory symptoms and byssinosis. The second study reveals high prevalence of byssinosis still existed in Taiwanese cotton mill, although the prevalence was declining. Smoking was found to show an additive effect on cotton dust exposure. Anti-smoking campaign, occupational health program to reduce the dust exposure, and periodical medical examination are measures to prevent from byssinosis.     

Endemic Byssinosis in an Egyptian Village

Previous epidemiological surveys of flax byssinosis may have underestimated the incidence of permanent pulmonary disability by failing to reach those who have had to leave work. In the present study a representative sample of the inhabitants of a village where flax is processed both in the homes and in small plants was examined for byssinosis. The one in five random sample included a total of 190 male family heads living in the village. Dust exposure was evaluated. The study showed that 48·4% of the sample had byssinosis, and this included 92·5% of those working with flax in their homes and 75% of those working in plants. Permanent disability from byssinosis was present in 2·6% of the total sample and 12·1% of those exposed to dust for more than 20 years, whereas 75·8% of the latter group had symptoms of the earlier grades of byssinosis. It is concluded that prolonged exposure to flax dust did not result in a high incidence of permanent disability, and that is disability is not necessarily an eventual outcome in flax byssinosis. The absence of air pollution in the village may play a role in lowering the probability of workers becoming disabled by byssinosis in spite of the high prevalence of symptoms.     

Effects of Histamine Aerosol in Byssinotic Subjects

The changes in symptoms and lung function tests of 26 cotton cardroom workers were investigated before and after inhalation of histamine aerosols. Three subjects with no chest symptoms and 11 with uncomplicated byssinosis showed no evidence of any pulmonary reaction, but 12 bronchitic byssinotic subjects showed evidence of the pulmonary hypersensitivity found in patients with chronic bronchitis alone.

These findings cast doubt on the possible role of non-antigenic histamine liberators in the mechanism of production of `return-to-work' tightness in byssinosis.

     

Some opinions on byssinosis in China

On the basis of some study results in China and reports from abroad, a conclusion should be drawn that leads to the recognition of a pneumoconiosis-like lesion of interstitial fibrosis. This disease is called "cotton pneumoconiosis" and we may classify these occupational lesions into four types: 1) byssinosis; 2) chronic obstructive pulmonary disease (COPD); 3) cotton fever; and 4) cotton pneumoconiosis. Byssinosis, COPD, cotton fever and cotton pneumoconiosis may be different types of responses due to the different duration of exposure, the different parts of bronchial tree (upper respiratory tract, small airway, and respiratory part) where deposition occurs, and the different components of cotton dust (broken cotton fibers, bracts, pericarps, bacteria, and fungi). These responses, which include histaminelike reaction, allergy, and stimulation of foreign material, happen in different symptoms of the syndrome among cotton mill workers. But no matter whether responses caused by inhalation of dust are inflammation or allergic reaction, cotton dust is foreign stimulation on deposited sites, causing lung fibrosis after lung stimulation. For the health of cotton workers, we must pay attention not only to the acute effects but also to the chronic lesions. We therefore suggest that these four types of occupational lung disorders caused by inhalation of cotton dust may be called by the joint name, "Byssinosis syndrome."     

Seasonal exposure to dust in flax processing in Egypt.

Previous evidence suggested that interruption of worker's exposure to flax dust may lead to severe symptoms of byssinosis on their return to work. In the present study, the prevalence and severity of byssinosis was studied in a sample of flax workers (n=577) who had been exposed to dust for six months each year. Byssinosis prevailed in 36.9% of them, and 32.3% of them had their FEV 1.0 sec reduced 10% at the end of the first morning work period (4 to 6 hours) of the week. Both syndromes were higher among seasonal workers than what would be predicted if they were pemanently exposed to flax dust. A hypothesis has been presented to interpret this finding.     

Effects of different vegetable dust exposures

Valić, F., and Žuškin, E. (1972).Brit. J. industr. Med.,29, 293-297. Effects of different vegetable dust exposures. In order to establish the rank of biological activity of vegetable dusts, five groups of non-smoking female workers exposed to similar concentrations of hemp, flax, cotton, sisal, and jute airborne dust, respectively, were compared as to the prevalence of byssinosis, chronic respiratory symptoms, and one-second expiratory volume changes over the Monday shift. The groups were selected in such a way as to differ in the distribution of age and length of exposure to the respective dust as little as possible.

The prevalence of byssinosis in hemp and flax workers was approximately equal (44% and 43% respectively), in cotton workers it was considerably lower (27%), while no byssinosis was caused by either sisal or jute dust. The highest prevalence of other chronic respiratory symptoms was recorded in hemp workers (39%), followed by flax (36%) and cotton workers (27%), while in sisal (13%) and jute workers (13%) it was the lowest.

Significant mean FEV_1·0 reductions over the shift were recorded in all the groups of textile workers with the largest reductions in hemp workers (19%) followed by flax (11%), cotton (8%), sisal (7%), and jute workers (5%). The application of orciprenaline before the shift diminished the mean acute FEV_1·0 falls over the work shift in all the groups studied.

     

Byssinosis in Hong Kong.

After a report in 1980 of the first three diagnosed locally cases and a preliminary epidemiological investigation that found little evidence of the disease, a survey was aimed at determining the prevalence of byssinosis in Hong Kong. Some 1776 workers in six cotton mills were studied using the standard MRC questionnaire and portable spirometers. Only 48 (2.7%) of the mill workers had symptoms acceptable for a diagnosis of byssinosis. The pattern of relation to dust exposure levels was similar to findings in other countries: blowing and carding process operatives had twice the prevalence rate of the spinners. Another 178 workers (10%) had symptoms of chest tightness or breathlessness or both that were not related to the first exposure after a break and therefore did not fit the standard diagnosis. Some 257 workers (14.5%) had chronic obstructive airflow disease but only 12 (4.7%) had chronic bronchitis. Job mobility had self selection of sensitive cases out of cotton dust exposure seem the most likely explanations for the low prevalence. The significance of non-specific lung ailments needs further assessment to elucidate the possible connection with cotton dust exposure.     

Byssinosis in Hong Kong

After a report in 1980 of the first three diagnosed locally cases and a preliminary epidemiological investigation that found little evidence of the disease, a survey was aimed at determining the prevalence of byssinosis in Hong Kong. Some 1776 workers in six cotton mills were studied using the standard MRC questionnaire and portable spirometers. Only 48 (2.7%) of the mill workers had symptoms acceptable for a diagnosis of byssinosis. The pattern of relation to dust exposure levels was similar to findings in other countries: blowing and carding process operatives had twice the prevalence rate of the spinners. Another 178 workers (10%) had symptoms of chest tightness or breathlessness or both that were not related to the first exposure after a break and therefore did not fit the standard diagnosis. Some 257 workers (14.5%) had chronic obstructive airflow disease but only 12 (4.7%) had chronic bronchitis. Job mobility had self selection of sensitive cases out of cotton dust exposure seem the most likely explanations for the low prevalence. The significance of non-specific lung ailments needs further assessment to elucidate the possible connection with cotton dust exposure.     

The health investigation of cotton textile workers in Beijing

This study reports findings from a survey of byssinosis among 289 cotton workers in certain cotton textile mills in Beijing. Incidence of byssinosis was 4.2% (12 cases). It decreased with a lower concentration of cotton dust and increased with yearly increment of cotton dust exposure. An elevation in body temperature over 37 degrees C was present among 14.2% of the workers on the first working day after rest. Acute lung function decrement was related to high dust concentration in the rooms. The higher the dust concentration in the rooms, the more evident was the chronic lung function decrement. Chronic bronchitis in cotton workers was higher than in controls. Incidence of byssinosis in smoking cotton workers was higher than in nonsmoking cotton workers.     

Histamine release from platelets for assay of byssinogenic substances in cotton mill dust and related materials.

Previous reports suggest that byssinosis, an asthma-like condition among textile workers, may be mediated in part by histamine liberated following inhalation of dust. A simple, sensitive, and reliable procedure using pig platelets which contain the unusually high concentration of 0.8-1.6 microgram histamine/10(9) cells has been devised for the assay of histamine-releasing factors in cotton mill dust and related materials, and has yielded results generally in accordance with earlier assays using chopped lung tissue. As little as 50--100 microgram of total extractable substances from cotton mill dust can be measured. The activity of the extract is associated with the non-dialysable high molecular weight portion. However, conditions of acid hydrolysis do not destroy the activity. Extracts of leaves from different varieties of plant are highly potent, which suggests that the factors responsible for byssinosis are widely distributed plant components, present in textile fibre plants and converted to a respirable form by handling processes. Ellagic acid and sodium metasilicate release histamine from pig platelets, and represent new classes of compounds with possible roles in the aetiology of byssinosis.     

Mill effect and dose-response relationships in byssinosis.

Four hundred and eighty-six textile workers in three cotton mills and one wool/synthetic mill were studied for symptoms and functional effects of workroom exposure to dust. Byssinosis was found in 5.7% of 386 cotton workers, with an apparent threshold level of 0.5 mg cotton dust/m3 of air. Mean post-shift functional declines were greater in workers exposed to greater than or equal to 0.2 mg/m3. Workers with byssinosis were unequally distributed, however, with respect to job category and mill; and these variables, rather than current dust exposure levels, accounted for the observed distribution of byssinosis prevalence rates. Variation in biological potency of different samples of cotton dust could be responsible for 'mill effect', the residual variation in response rates by mill after controlling for variation due to dust exposure. A number of other potential influencing variables that are likely to be distributed unequally by mill should also be considered. Mill effect should be assessed in large-scale studies of byssinosis, most of which have analysed biological response rates by combining mill and other variables to examine first-order effects of dust dosage. In such analyses, much of the observed variability may be due to factors other than dust dosage.     

Histamine release from platelets for assay of byssinogenic substances in cotton mill dust and related materials.

Previous reports suggest that byssinosis, an asthma-like condition among textile workers, may be mediated in part by histamine liberated following inhalation of dust. A simple, sensitive, and reliable procedure using pig platelets which contain the unusually high concentration of 0.8-1.6 microgram histamine/10(9) cells has been devised for the assay of histamine-releasing factors in cotton mill dust and related materials, and has yielded results generally in accordance with earlier assays using chopped lung tissue. As little as 50--100 microgram of total extractable substances from cotton mill dust can be measured. The activity of the extract is associated with the non-dialysable high molecular weight portion. However, conditions of acid hydrolysis do not destroy the activity. Extracts of leaves from different varieties of plant are highly potent, which suggests that the factors responsible for byssinosis are widely distributed plant components, present in textile fibre plants and converted to a respirable form by handling processes. Ellagic acid and sodium metasilicate release histamine from pig platelets, and represent new classes of compounds with possible roles in the aetiology of byssinosis.     

Mill effect and dose-response relationships in byssinosis

Four hundred and eighty-six textile workers in three cotton mills and one wool/synthetic mill were studied for symptoms and functional effects of workroom exposure to dust. Byssinosis was found in 5.7% of 386 cotton workers, with an apparent threshold level of 0.5 mg cotton dust/m3 of air. Mean post-shift functional declines were greater in workers exposed to greater than or equal to 0.2 mg/m3. Workers with byssinosis were unequally distributed, however, with respect to job category and mill; and these variables, rather than current dust exposure levels, accounted for the observed distribution of byssinosis prevalence rates. Variation in biological potency of different samples of cotton dust could be responsible for 'mill effect', the residual variation in response rates by mill after controlling for variation due to dust exposure. A number of other potential influencing variables that are likely to be distributed unequally by mill should also be considered. Mill effect should be assessed in large-scale studies of byssinosis, most of which have analysed biological response rates by combining mill and other variables to examine first-order effects of dust dosage. In such analyses, much of the observed variability may be due to factors other than dust dosage.     

An environmental and medical study of byssinosis and other respiratory conditions in the cotton textile industry in Egypt

This study was conducted in a typical Egyptian textile plant located in Alexandria. Male workers from all operations (N = 506) were examined and their dust exposures were assessed. Results showed that airborne dust concentrations were very high and that the plant fraction is mostly concentrated in respirable dust. Byssinosis prevailed in 21% of workers in opening and cleaning sections and in 13% in carding and combing rooms, but was found in none of the workers in drawing, twisting, and spinning operations, in only 1.1% in weaving, and in 3.1% of workers in other “auxiliary” occupations. The rare prevalence of byssinosis among the latter workers' groups was attributed to the workers' continuous exposure without fixed weekend interruption, the personal and family history of exposure to cotton, the low proportion of plant materials in dust evolved in related operations, the fine quality of Egyptian cotton, and/or the population characteristics of Egyptian workers. Reduction in FEV_1.0 at the end of the first work shift after absence from work occured more often than byssinosis, which indicates the importance of this test for the early detection of effects of cotton dust exposure. It is suggested that a nationwide study in the cotton textile industry is indicated.