Magnesium and calcium in drinking water and cardiovascular mortality

Data on the hardness of drinking water were collected from 27 municipalities in Sweden where the drinking water quality had remained unchanged for more than 20 years. Analyses were made of the levels of lead, cadmium, calcium, and magnesium. These water-quality data were compared with the age-adjusted mortality rate from ischemic heart and cerebrovascular disease for the period 1969-1978. Lead and cadmium were not present in detectable amounts except in one water sample. A statistically significant inverse relationship was present between hardness and mortality from cardiovascular disease for both sexes. Mortality caused by ischemic heart disease was inversely related to the magnesium content, particularly for the men (P less than 0.01). The rather small set of data supports results from previous studies suggesting that a high magnesium level in drinking water reduces the risk for death from ischemic heart disease, especially among men, although the possible importance of confounding factors needs further evaluation.

Increased blood monocyte procoagulant activity in cotton mill workers

Blood monocyte procoagulant activity has previously been related to delayed type hypersensitivity. In this study, cotton workers exposed to cotton dust containing endotoxin and subjects not exposed to organic dusts, were examined. Blood mononuclear cells from the two groups were incubated with and without endotoxin and the recalcification time was measured. Mononuclear cells from cotton workers had a decreased baseline procoagulant activity but an increased response to endotoxin, suggesting cellular sensitization to the endotoxin present in cotton dust.

A clinical and endocrine study on the effect of orally administered bacterial endotoxin in adult pigs and goats

Endotoxin of Gram-negative bacteria was orally administered in 5 female pigs and 8 male goats. Two of the gilts were pregnant. A solution of lipopolysaccharide (LPS) of Enterobacter agglomerans was mixed into the feed ration of the pigs (40 mg/animal), and given by gastric tube into the rumen of the goats (1-20 mg/animal). Jugular venous blood was collected and clinical signs, rectal temperature and WBC counts were recorded for 12-24 hours. Plasma concentrations of the major plasma metabolite of PGF2 alpha, 15-keto-13,14-dihydro-PGF2 alpha were determined in both species, progesterone concentration only in pigs. The pigs showed slight to severe signs of endotoxemia. Increases in rectal temperature and levels of the PGF2 alpha metabolite occurred in 3 gilts. Progesterone level and the total WBC counts remained unchanged. Differential counts followed irregular patterns mostly within the normal range. The goats showed slight signs of discomfort. Temperature increased in one animal. No other parameters were altered after the intake of LPS. The observations in pigs indicate that endotoxin either penetrated the intestinal barrier causing systemic endotoxemia or induced inflammatory reactions in the intestine activating inflammatory mediators.

Environmental exposures with decreased risks for lung cancer?

The case for a decreased risk of lung cancer after exposure to environmental agents is evaluated using toxicological and epidemiological data. Experimental evidence demonstrates that exposure to substances which produce an inflammatory response in the lung, such as bacterial endotoxins, causes an increase in the secretion of inflammatory mediators and substances with a particular effect on tumour cells such as tumour necrosis factor (TNF). Other irritant agents, such as tobacco smoke, may also induce an activation of macrophages at low levels of exposure. Epidemiological evidence from several studies suggests that people exposed to dusts containing bacterial endotoxins have a lower lung cancer incidence than those who are unexposed. There are also some data suggesting that in certain ethnic groups, females smoking a small number of cigarettes/day, might have a lower risk for lung cancer than non-smokers. These data provide support for a hypothesis that low-dose exposures to some air pollutants might result in a decreased risk of lung cancer.

Health effects of cotton dust exposures

The characteristics of the effects of exposure to cotton dust were adequately described more than 50 years ago. Symptoms of airway irritation, cough with or without phlegm, and Monday morning chest tightness are typical. The symptoms caused by exposure to cotton dust are similar to those induced by other organic dusts. A common pathology is acute or chronic inflammation, and bacterial endotoxins seem to be the causative agents for the acute and some chronic reactions.

Bronchial hyperreactivity among pig and dairy farmers

The presence of work-related symptoms, pulmonary functions, and bronchial reactivity were studied in farmers working with dairy animals or pigs. An increased incidence of the organic dust toxic syndrome, cough, and throat irritation was found. Pulmonary function baseline values were close to normal, and no significant decreases occurred over the work period. Bronchial reactivity was increased.

Experimental allergic alveolitis after inhalation of mouldy hay

Guinea pigs were exposed by inhalation to an aerosol of dust from mouldy hay or cell bound bacterial endotoxins. Pulmonary histology and free lung cells were evaluated 24 hr after exposures lasting from one day to five weeks. In animals exposed to mouldy hay, there was a progressive increase in the number of macrophages and neutrophils and after three weeks a sharp increase in lymphocytes. Following endotoxin exposure, neutrophils increased greatly in number with one day's exposure but after longer exposures, numbers differed little from normal, suggesting adaptation. Histopathology of lungs from animals exposed to mouldy hay demonstrated the presence of alveolar cell infiltrates and early granulomas, that were similar to allergic alveolitis (AA). This model for AA could be used both to assess the importance of different agents in mouldy hay and to evaluate the risk of AA from new kinds of organic dusts.

Pulmonary function and symptoms after inhalation of endotoxin

In previous experiments, a good relationship was demonstrated between the amount of airborne bacterial endotoxin and acute reactions after exposure to organic dusts. In the present study, 77 naive subjects were exposed to isolated endotoxin (IE) or endotoxin attached to bacterial cells (CE). Both preparations were obtained from Enterobacter agglomerans, which is a major bacterial species in many organic dusts. The major physiologic effect caused was a dose-related decrease in transfer factor, as measured by carbon monoxide diffusion. Half of the subjects reported fever and about one-third a subjective feeling of chest tightness. The exposure also caused a dose-related but small decrease in FEV1. A slightly increased bronchial reactivity was demonstrated at 4 h after endotoxin exposure. The minute volume after CO2 exposure was marginally affected. The results further support the conclusions from epidemiologic and experimental studies that the bacterial endotoxin is responsible for the acute reactions seen after exposure to many organic dusts, including that derived from cotton.

Effects of exposure to dust in swine confinement buildings--a working group report

Pulmonary and other symptoms among workers in swine confinement buildings were evaluated by an international working group. In several studies in five different countries a total of about 2000 workers has been studied in clinical and epidemiologic investigations. Symptoms indicative of acute and chronic airway inflammation were widespread, as were systemic reactions of organic dust toxic syndrome. The base-line, and across workshift, pulmonary function changes were moderate. There was no evidence that antigen-antibody reactions are important in the pathogenesis. Longitudinal studies are recommended to establish the relationship between acute and chronic symptoms and end stage disease.

Lung cell reactions in guinea pigs after inhalation of asbestos (amosite)

To study the long-term effect of inhaled asbestos, guinea-pigs were exposed to airborne amosite at a concentration of 49 mg/m3, 2 h/day for 3 or 6 weeks and examined up to 2 years after exposure. Macrophages in lung lavage fluid (LLF) were increased at 16, 24 and 93 weeks and lymphocytes at 24 weeks. Examination of lung wall cells (LWC) 2 years after exposure compared to cells obtained by LLF showed higher proportions of LWC lymphocytes and neutrophils. Percoll gradient centrifugation of these cells showed a higher proportion of high density macrophages in LLF from the amosite-exposed animal and an increased number of low density lymphocytes in the LW. Cathepsin D was increased in LLF at 8 and 24 weeks and in alveolar macrophages 24 weeks and 2 years after exposure. Fibroblast cultures exposed to LLF did not show any statistical significant changes in their collagen synthesis. Histology 93 weeks after exposure showed macrophage and mediastinal lymph node accumulation of asbestos, as well as collagen in alveolar walls. Granulomas were found in the vicinity of blood vessels and in connection with the bronchioles. The data suggest that amosite at low doses ultimately causes fibrosis with a reaction pattern different from that seen in silicosis. The inflammation and fibrosis seems to develop only within the interstitium.

Outcome of pregnancy in relation to irregular and inconvenient work schedules

The relation between irregular and inconvenient working hours and the outcome of pregnancy was studied among women employed at a hospital in Sweden some time between 1980 and 1984. A questionnaire was distributed to 807 women; 81% replied. The pregnancies were divided into six groups with respect to work schedules during pregnancy. A slightly, but not significantly, increased risk of miscarriage was found in women who worked irregular hours or rotating shifts compared with women who worked only during the day (RR = 1.44, 95% confidence interval 0.83-2.51). Infants of non-smoking mothers who worked irregular hours had significantly lower birth weights than infants of non-smoking women working day time only. This difference was largest at birth order 2+. Similar results were found for infants of this birth order whose non-smoking mothers worked evenings or rotating shift.

Cell recruitment into lung wall and airways of conventional and pathogen-free guinea pigs after inhalation of endotoxin

The cell kinetics of the acute inflammatory response to inhaled endotoxin (lipopolysaccharide, LPS) was studied in the lungs of conventional (CV) and pathogen-free (SPF) guinea pigs. Airway cells were obtained by bronchoalveolar lavage (BAL). Lung wall cells were prepared via collagenase digestion of lung tissue slices. Acute exposure to LPS triggered the influx within 4 to 12 h of equivalent numbers (approximately 70 x 10(6)) of neutrophils into the lung walls of both CV and SPF guinea pigs. The recruited neutrophils then proceeded into the airways of CV animals, and by 48 h all recruited neutrophils were recoverable by BAL. In contrast, only one third of recruited neutrophils in the lungs of SPF animals moved from the lung wall into the airways. Analysis of neutrophil chemotactic factor (NCF) production identified lung wall cells as the major source of LPS-induced NCF activity in both groups and as virtually the sole source in SPF animals. The results emphasize the importance of studies on the precise lung tissue distribution of both recruited neutrophils, and endogenous NCF-producing cells, in elucidating the acute inflammatory response in the lungs.

Environmental and health studies of farm workers in Swedish swine confinement buildings

The relation between the health of workers and the environment in swine confinement buildings was investigated in a study of 57 workers on 30 swine farms in southern Sweden and 55 matched controls. Swine workers reported significantly higher frequencies of respiratory symptoms, more frequent colds and absence due to chest illness, and a history of pneumonia. The increased frequency of symptoms of respiratory disease was related to the number of years and percent of the day spent working with swine. Symptoms were also associated with respirable dust, total dust, endotoxin in total dust, and number of microbes in the air of the work environment. In a multiple regression analysis of the relation between 16 different environmental parameters to work period shifts of five pulmonary function parameters, endotoxin was found to be significantly related to the FEV1 in a dose dependent way.

Outcome of pregnancy in women engaged in laboratory work at a petrochemical plant

The aim of the investigation was to study whether laboratory work or other types of chemical work at one petrochemical plant were associated with an increased risk for miscarriage or reduced birthweight. The study was based on questionnaire data for 95% of the women working at the plant between 1973 and 1987. A statistically significant difference between observed and expected number of miscarriages (p less than 0.05) was seen during the period 1970-1974 among women working in one of the laboratories during the first trimester. No suspicions could be raised against any specific chemical as a cause of the unsuccessful pregnancies. The results do not indicate the presence of an increased risk today.

Modulation of acute endotoxin pulmonary inflammation by a corticosteroid

The effect of corticosteroid on an acute inflammation in the lungs was studied in guinea pigs exposed to an aerosol of bacterial endotoxin, the subsequent inflammatory response was evaluated counting the number of cells obtained from airway lavage and in the lung interstitium as well as the chemotactic effect of alveolar macrophages. Pretreatment with corticosteroid decreased the number of neutrophils in the airways at 24 hours after exposure but did not influence neutrophils in airways or lung interstitium at 4 hours after exposure, not the secretion of chemotactic factor(s) from alveolar macrophages at that time. It is suggested that the antiinflammatory effect of corticosteroids is a protective effect on the epithelium, preventing the late influx of serum fluid and neutrophils into the airways.

Plant constituents of cotton dust and lung effects after inhalation

Experiments were performed to assess pulmonary reactions after inhalation of cotton dusts with different levels of tannins, terpenoid aldehydes and bacterial endotoxins. Guinea-pigs were exposed to cotton dust. Free lung cells were obtained by lavage 24 h later. A dose-response relationship was found between the number of neutrophils and the amount of endotoxin in the dust. No influence of terpenoid aldehyde or tannin levels could be detected. Cotton mill workers were exposed to dust from glanded and glandless cottons in an experimental cardroom. The average decreases in forced expiratory volume in one second (FEV1) over the workday after carding the two cottons were the same, although levels of dust, tannin or terpenoid aldehydes were different. The level of airborne endotoxin was, however, equal. The results support observations from other studies on the importance of endotoxin for the development of the acute reactions observed after cotton dust exposure.