Occupational and environmental exposures and nonspecific lung disease--a review of selected studies

Selected studies show that nonspecific lung diseases are a major occupational and environmental health hazard. Exposure to mineral dusts (such as cement and brown coal) and organic dusts (cotton, hemp and flour) as well as manganese and gaseous irritants causes significant upper respiratory tract injury. Possible additive effects of mixed exposures, combined exposure to dusts and gaseous irritants of the upper respiratory tract, individual susceptibility, and mechanisms of nonspecific respiratory effects of exposures are considered. Interpretation of the results is difficult due to uncontrolled confounding. Measures for preventing lung impairments include exposure reduction and preemployment examination of workers.     

Denied worker''s compensation claims: what physicians can and cannot do

Allergologic study covered 500 workers who underwent exposure to hexavalent chromium and 150 workers exposed to formaldehyde. The study proved high specificity and diagnostic value of endonasal provocation with hapten. Endonasal provocation with chemical antigen helps to disclose an etiologic role of the hapten in upper and lower respiratory tract allergy. Endonasal provocation with chemical allergen reveals latent sensibilization of respiratory tract mucosa in apparently healthy workers with no allergic signs. The data obtained could be valuable for diagnosis of occupational allergies, for examination of capacity to work, for occupational examinations, for rational medical and occupational rehabilitation.     

Effect of environmental pollution on medical visits for respiratory infections in children in Mexico City

OBJECTIVE: To model the variability of medical visits by children for respiratory reasons as a consequence of the daily changes in environmental pollution observed in the emergency and family medicine departments of a hospital of the Instituto Mexicano del Seguro Social located in the southwest of Mexico City during 1993. MATERIALS AND METHODS: The correlation between the presence of upper and lower respiratory tract infections and exposure to ozone and nitrogen dioxide was studied. To model this association, the authors used multivariate Poisson regression models with linear and non-linear risk, with lag periods between the environmental measurements and the medical visits of one, two and three days, as well as the average of the measurements of three, five and seven days previous to the visit. RESULTS: The model estimates that an increment of 50 ppb in the daily average of ozone would cause an increase of 9.9% in emergency visits due to high respiratory tract infections during the winter, which could rise to 30% if the increment would last five consecutive days in average. CONCLUSIONS: Results suggest that exposure of children younger than 15 years of age to ozone and nitrogen dioxide significantly affect the number of medical visits for respiratory causes in this part of Mexico City.     

Estimation of the cytogenetic homeostasis in natural populations of small murine rodents from the Lower (Astrakhan') and Middle (Chapaevsk) Volga regions

Frequencies of chromosomal aberrations were estimated in the bone marrow of two background small rodent species, the bank vole (Clethrionomys glareolus) and the house mouse (Mus musculus) from the middle (Chapaevsk, Samarskaya oblast) and lower (Astrakhanskaya oblast) Volga regions. The majority of chromosomal aberrations were chromatid deletions. In the studied species, cytogenetic disturbances were most prevalent in areas where the anthropogenic environmental pollution was maximum. The lowest frequencies of disturbances were observed in the control areas, where the environmental pollution was insignificant. Thus, anthropogenic exposure caused disturbances of cytogenetic homeostasis in different small rodents living in different regions.     

The characteristics of formulating a diagnosis in diseases of the temporomandibular joint

Pulmonary diseases caused by dust occupy a leading place in occupational morbidity structure. Those diseases inspire much attention due to their high prevalence, especially in ecologically hazardous regions where the workers are under "double exposure". Upper respiratory tract diseases serve as a trigger for all respiratory disorders in workers exposed to dust. Early diagnosis of respiratory disorders includes history, clinical data, X-ray examination and assessment of pulmonary ventilation and together with concurrent cardiovascular diagnosis is necessary for well-justified prophylaxis.     

Lead content in edible wild mushrooms in northwest Spain as indicator of environmental contamination

Lead content was determined in wild growing mushrooms collected from two different areas in the Province of Lugo (NW Spain). It has been analyzed by graphite furnace atomic absorption spectrometry in 95 samples of 13 species (7 mycorrhizals and 6 saprophites). In an assessment of lead concentrations, the following factors have been considered: species and ecology, morphological portion, and traffic pollution. The average lead concentration of the samples was 1 ppm dry weight (dw). Saprophite species presented higher levels than mycorrhizal ones (< 1 ppm), Coprinus comatus reaching the maximum mean concentration with 2.06 and 2.79 ppm of dw in the hymenophore and the rest of the fruit body. Morphological portion, statistically, did not show significant difference between the two portions; however, Macrolepiota procera always presented lead high levels in the hymenophore in all samples. The effect due to traffic pollution has been specially observed in Coprinus comatus, presenting the highest concentration with values of 6.51 and 10.43 ppm, respectively, in samples collected in the city center. This species, as other researchers have indicated, could be considered as an indicator by lead contamination. The contribution of mushrooms to the weekly intake of lead was calculated and the possible health risk for the consumer is pointed out. These data are of great importance in view of toxicology and partly environmental protection.     

Subclasses of LpA-I in coronary artery disease: distribution and cholesterol efflux ability

To determine the effect of air pollution in Mexico City on respiratory health, patient visits for upper respiratory tract infections were monitored in five clinics. Levels of ozone, nitrogen dioxide, carbon monoxide, and sulfur dioxide, and climatological variables were collected. Correlations of filtered data revealed an association between NO2 and O3 with an increase in visits to clinics because of respiratory problems. Autoregressive analysis indicated that pollutant levels/respiratory visits associations remained significant even after simultaneous inclusion of temperature, suggesting that air pollution was associated with 10 to 16% of the clinic visits. The relative risk indicated that high levels of O3 and NO2 could increase the total number of clinic visits to between 19 and 43% above average. The other pollutants and the control group did not demonstrate significant associations.     

Effects of air pollution on health

Air pollution is composed of a particulate phase and a gaseous phase. The particulate phase, consisting of dust and aerosols, is the vehicle of toxic pollutants, transporting them into the respiratory tract. The irritants (sulphur dioxide, nitrogen oxides, aldehydes, and hydrocarbons) are the most important pollutants as regards health; the mucous membranes of the eyes and the respiratory tract are mostly affected. Other substances penetrate into the organism where they can develop actions harmful to various organs (carbon monoxide), generate cancer (polyaromatic hydrocarbons) or attack enzymatic systems (lead). Epidemiologic studies have revealed that populations exposed to high degrees of air pollution show increased mortality, which is mainly due to illnesses of the respiratory tract. Atmospheric pollution can also cause sensations of unpleasantness due to irritations of the eyes and the respiratory tract, bad odours, and the impairment of visibility and sunlight.     

Upper respiratory tract disease and mycoplasmosis in desert tortoises from Nevada

A population of desert tortoises (Gopherus agassizii) at Yucca Mountain (Nevada, USA) was monitored during four sampling periods using enzyme-linked immunosorbent assays (ELISA) to determine the percentage of individuals that had been exposed to Mycoplasma agassizii, a causative agent of upper respiratory tract disease. Respiratory tract disease has been considered a significant factor in the decline of desert tortoise populations in the Mojave Desert (USA). Few differences between sexes in ELISA values or percentages testing positive were noted. From 15 to 23% of samples per period tested positive for exposure to the mycoplasma. However, we noted few clinical signs of upper respiratory tract disease. This is in contrast to an earlier study which reported a similar proportion of seropositive tortoises as well as a high percentage of tortoises with clinical signs. However, our results are consistent with that study's conclusion that seropositivity for M. agassizii was a poor predictor of the likelihood to exhibit clinical signs of upper respiratory tract disease. Earlier reported epizootics of mycoplasma-associated respiratory disease occurred mainly during times of drought. Our samples were collected during a period of average to above-average rainfall, suggesting that manifestation of clinical signs of the disease may depend upon the physiological condition of tortoises which, in turn, is related to environmental conditions.     

Plutonium in fish, algae, and sediments in the Barents, Petshora and Kara Seas

This work contributed to a joint research programme between the Finnish Centre for Radiation and Nuclear Safety and the Murmansk Marine Biological Institute in the Arctic. Radioanalyses for plutonium isotopes were performed on more than 50 sediment samples, 12 algae samples and 19 fish samples. Plutonium concentrations in algae and fish samples, including fish meat, bone and liver, were low or in many cases below detection limits. Some differences in plutonium concentrations of sediments were found between different sampling areas. However, the concentrations were low. The Pu isotopic ratios were similar to those found in environmental samples generally when Pu is derived from global fallout or discharges from reprocessing plants. No local enhancement of plutonium contamination was found in the marine areas studied. However, the sampling locations represent only areas of free access; prohibited military areas of North-west Russia with potential pollution sources were not included.     

The fungal flora of Ankara air in January 1972 and 1974 and its relationship to allergic diseases

The fungal flora of the air in Ankara was searched during first week of January 1972 and 1974. Different areas of the city were chosen for investigation. The central and outskirt areas showed different patterns of fungal flora during January 1972 and January 1974. In the central areas there was a remarkable decrease in yeast flora between the two years. However, mould flora was increased in some extent. No notable difference could be detected in outskirt areas. Penicillium and Aspergillus species were isolated most frequently. It is concluded that this flora was influenced by heavy pollution of the air in Ankara. This pollution is caused mainly by: (1) Heating systems with crude coal and oil, (2) Heavy motor traffic, (3) Geographical situation of the city, cup-shaped land with poor air draughts.     

Efficacy of transbronchial biopsy in pulmonary vaculitides

This study was performed to determine the value of transbronchial biopsy (TBB) in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides and mild-to-moderate pulmonary involvement. Included in the study were 19 patients with Wegener's granulomatosis (WG) and six patients with Churg-Strauss syndrome (CSS) with evidence of active pulmonary disease but without gross parenchymal lesions accessible by radiologically guided biopsy. All of the patients had undergone staging examinations which included TBB taken from peripheral lung tissue and from any focal tracheobronchial lesions. Any suspicious lesion in the upper respiratory tract was biopsied by an otolaryngologist and the number of positive biopsies was compared with that of TBB. In the WG patients, only two out of 17 biopsies of alveolar tissue yielded histopathological findings supporting the diagnosis of WG. In five WG patients, ulcerative or exophytic airway lesions were found whose histopathologies were invariably positive. Otolaryngological examination revealed abnormal findings in 19 WG patients and biopsies from these sites yielded positive results in 13 instances. In CSS, TBB produced a diagnostically helpful histopathology in four of six cases and biopsies from the upper respiratory tract were positive in five out of six cases. We conclude that transbronchial biopsies of alveolar tissue are seldom positive in Wegener's granulomatosis patients with mild-to-moderate pulmonary disease unless they are taken from grossly abnormal lung areas. Conversely, ulcerative, exophytic or stenotic tracheobronchial lesions had a high rate of positive findings. These results further suggest that the upper rather than the lower respiratory tract should be the biopsy site of first choice in Wegener's granulomatosis. In Churg-Strauss syndrome, the upper and lower respiratory tract seem to yield a roughly equal number of positive biopsies.     

Intersubject variability of functional areas in the human visual cortex

A review of studies made in the compost production industry showed the biological agents posing a risk for workers were fungi and thermophile bacteria, gram-negative bacteria and endotoxins, with a prevalent inhalation exposure to airborne contaminated dusts. Medical examinations revealed cases of extrinsic allergic alveolitis due to A. fumigatus, and more frequently irritative and infectious disorders occurring especially in conditions of poor environmental hygiene and macroscopic dust pollution. For the evaluation of the air dispersion of microorganisms, which is high in compost transport and turning operations, at present no exposure limit values are available for biological agents; nevertheless, the concentrations measured were often higher than the limit values proposed for other manufacturing sectors by individual authors and by regulatory agencies in Europe, and were comparable to values observed in other industrial settings for which adverse health effects have been shown. Although the number of studies available are few in number, the results suggest that the hazards posed by microorganisms and the poor environmental hygiene conditions often encountered can undoubtedly be a source of risk for workers, which at present is difficult to establish but significant considering the high airborne concentrations of contaminated dust. Besides technical measures to avoid environmental macroscopic dispersion of dusts, measurement of airborne microbiological contaminants is also recommended. Health surveillance needs to be aimed at identifying subjects with hypersusceptibility to the infectious action of the pathogenetic and/or allergenic agents or with hypersensitivity to the same, and also to periodic control of respiratory organs.     

Molecular epidemiology of Stenotrophomonas maltophilia isolated from clinical specimens from patients with cystic fibrosis and associated environmental samples

Stenotrophomonas maltophilia was isolated from the respiratory tracts of 41 (25%) of 163 children attending our pediatric cystic fibrosis unit between September 1993 and December 1995. The extents of S. maltophilia contamination of environmental sites frequented by these patients were investigated with a selective medium incorporating vancomycin, imipenem, and amphotericin B. Eighty-two isolates of S. maltophilia were cultured from 67 different environmental sites sampled between January and July 1996. The organism was widespread in the home environment, with 20 (36%) and 25 (42%) of sampled sites positive in the homes of colonized and noncolonized patients, respectively. In the nosocomial setting, it was isolated from 18 (32%) sites in the hospital ward and from 4 (17%) sites in the outpatient clinic area. The most common sites of contamination were sink drains, faucets, and other items frequently in contact with water. All environmental and clinical isolates were genotyped with enterobacterial repetitive intergenic consensus sequences as primers. A total of 33 of the 41 patients were colonized with unique strains, and four pairs of patients shared strains. Further characterization by pulsed-field gel electrophoresis after digestion with XbaI found that there was no evidence of patient-to-patient transmission; however, there was some evidence that a small number of patients may have acquired the organism from the hospital environment. Resampling of environmental sites in the hospital ward in January 1997 revealed evidence of genetic drift, complicating the accurate determination of environmental sources for clinical strains. The source of the majority of S. maltophilia strains colonizing the respiratory tracts of these patients with cystic fibrosis remained uncertain but may have represented multiple, independent acquisitions from a variety of environmental sites both within and outside the hospital.     

Diagnosis of bronchopulmonary infections by quantification of microflora

The quantification of bacteria and fungi in sputum or bronchoaspirate is of clinical value for the diagnosis of respiratory tract infections. We have developed an easy method to count the micro-organisms in patients with respiratory tract infections. This consists of the quantification of micro-organisms by subsequent streakings of a calibrated loop on agar. The correlation between microbiological quantitative data and the clinical status of patients with lower respiratory tract infections is discussed. The data seem to indicate that certain bacteria present in sputum or bronchoaspirate above a certain concentration may be responsible for lower respiratory tract infections. In patients with immunological disorders or chronic pathologies even lower concentrations of micro-organisms in bronchial secretions probably are enough to cause infections. The advantage of this counting method of the microbic species from the respiratory tract consists of their quantification: thus we can attribute an etiological role to a high concentration of the germs, while micro-organisms at low concentrations are probably contaminants. By this method isolated colonies are obtained after 12-18 hours. The bacterial quantification, by respiratory samples examination of the same patient in the following days, allows us to evaluate the efficacy of antibacterial therapy, producing a reduction of bacterial concentration.     

Respiratory symptoms and cough reflex in populations exposed to different degrees of environmental pollution

BACKGROUND: Santiago is a city with a high degree of environmental pollution caused by particulate matter and ozone, producing adverse effects in the respiratory system. AIM: To compare respiratory symptoms and cough reflex in adults from Santiago and from a rural area with low levels of environmental pollution. SUBJECTS AND METHODS: One hundred twenty six non-smoker adults from Santiago and 116 from a rural area with low levels of pollution answered a respiratory symptom questionnaire. Of these 101 subjects from Santiago and 116 from the rural area inhaled doubling concentrations of capsaicin from 0.5 to 500 microM or until five coughs were elicited. The lowest concentration eliciting 2 or more coughs (CD2) or 5 or more coughs (CD5) was recorded. Levels of environmental particulate matter were also recorded in both locations. RESULTS: Levels of particulate matter were 102 +/- 41 and 64 +/- 24 micrograms/m3 in Santiago and the rural area respectively. People from Santiago had higher rates of throat clearing, cough and phlegm. CD2 geometric mean and confidence limits in Santiago and the rural area were 6.9 (5.2-7.4) and 2.8 (2.7-2.9) respectively (p < 0.001). No differences in CD5 were observed between both locations. Multivariate analysis disclosed the variable location (city) as the only independent predictor of respiratory symptoms. CONCLUSIONS: The increased CD2 found in Santiago suggests that the higher rates of respiratory symptoms related to air pollution can be associated to a decreased sensitivity of the cough reflex.     

Adverse environmental conditions in the respiratory and medical ICU settings

Sleep deprivation and fragmentation occurring in the hospital setting may have a negative impact on the respiratory system by decreasing respiratory muscle function and ventilatory response to CO2. Sleep deprivation in a patient with respiratory failure may, therefore, impair recovery and weaning from mechanical ventilation. We postulate that light, sound, and interruption levels in a weaning unit are major factors resulting in sleep disorders and possibly circadian rhythm disruption. As an initial test of this hypothesis, we sampled interruption levels and continuously monitored light and sound levels for a minimum of seven consecutive days in a medical ICU, a multiple bed respiratory care unit (RCU) room, a single-bed RCU room, and a private room. Light levels in all areas maintained a day-night rhythm, with peak levels dependent on window orientation and shading. Peak sound levels were extremely high in all areas representing values significantly higher than those recommended by the Environmental Protection Agency as acceptable for a hospital environment. The number of sound peaks greater than 80 decibels, which may result in sleep arousals, was especially high in the intensive and respiratory care areas, but did show a day-night rhythm in all settings. Patient interruptions tended to be erratic, leaving little time for condensed sleep. We conclude that the potential for environmentally induced sleep disruption is high in all areas, but especially high in the intensive and respiratory care areas where the negative consequences may be the most severe.     

Salmonella prevalence in crops of Ontario and Quebec broiler chickens at slaughter

Swabs of crop contents of 635 broiler chickens were obtained from 9 Ontario and 12 Quebec processing plants and cultured for Salmonella to determine prevalence in broiler crops. Serotypes of positive cultures were determined to evaluate the serotype profile. The overall prevalence of contamination was low (4.3%). Prevalence was higher in broilers sampled in Quebec (5.8%) than in those sampled in Ontario (2.2%). In Quebec, there were differences in prevalence among the groups of broilers sampled at the various plants. These differences were believed to be attributable to differences in Salmonella prevalence among groups of flocks delivered to the plants due to the limited exposure of the chickens to the plant. The serotype profile of Salmonella isolated from the crops of broilers in this study was similar in several respects to profiles obtained from other surveys of Canadian broiler flocks using either environmental samples or cloacal swabs. Similarities included: predominance of Salmonella hadar and Salmonella heidelberg; several other common serotypes at a low prevalence; little Salmonella enteritidis isolated in other studies, and no S. enteritidis isolated in this study. Results of this field survey of Salmonella in crops of broilers are similar to those of Canadian studies of other internal and environmental sites of broilers. The similarity indicates that monitoring of Salmonella environments of flocks of live broiler chickens should define profiles of Salmonella contamination of the carcasses and would also aid in determination of Salmonella contamination status of broiler flocks. Such information would assist efforts to reduce Salmonella contamination in broiler chickens.     

A comparative study of self-administration of morphine into the amygdala and the ventral tegmental area in mice

The concentrations of zinc, cadmium and copper were determined in different benthic algal species from some sites located in Guanabara Bay, Sepetiba Bay and Ribeira Bay (State of Rio de Janeiro). The aim is to verify the possibility of using algae as indicators of metallic contamination in these areas. According to our results, the highest concentrations of Zn and Cd in algae were observed in Sepetiba Bay. In this region, the differences among the concentrations of the metals were analysed in three sampling sites. Padina gymnospora was the species recommended to monitor the contamination of Zn and Cd in Sepetiba Bay, for the following reasons: 1) its great abundance and distribution in the areas, and 2) its high ability to accumulate metals. More studies are suggested to evaluate the levels of metals in Guanabara Bay.