| Objectives1. To detect whether there is a fibrogenic potential on rat lung from fur dust exposure.2. To conduct an environmental mycological study, an investigation of respiratory symptoms, chest X - ray examinations, and analysis of antibodies to fungi. To discusse possible causes of respiratory impairments in the fur - processing factory.3. To determine whether there- was a dose - response relationship between the cumulative dose of fur dust exposure and respiratory system injury. To propose an exposure limit for fur dust.Methods1. Experimental study on fibrogenic effect of fur dust on rat lung Dust samples; Three fur dust (wool dust) samples were collected from the surfaces of the machines in the work areas for the carding and sewing procedures. These dust samples were repeatedly cut with scissors and then pestled finely in an agate mortar. Quartz dust was provided by the Institute of Industrial Hygiene and Occupational Disease, Chinese Academy of Preventive Medicine.Animals and experimental design: Wistar rats, weighing 180 -220g, were randomly divided into four groups: carding group, sewing group, quartz group and control group (saline). Rats, lightly anethetized with ether, were instilled intratracheally. The total dose (100mg for each rat) was administered in 3 instillations given over a period of 45 days (40mg the first time, the second time and third time 30mg each) . The quartz dust was instilled intratracheally once for a dose of 40mg. Rats were sacrificed at 1, 3 , 6 and 12 months after the last adi-ministration. Small pieces of lung tissue of each rat and hilar lymph nodes were routinely sectioned at 5 m, then stained with hematoxylin and eosin ( HE ) , Foot, and van Gieson stains (VG) .12 months after instillation, some lung tissues were routinely fixed and sectioned , then were observed under a TSMT - 300 scanning electron microscope ora JEM -1200 transmission electron microscope.The remaining lung tissues of each group, at 1, 3 , 6, and 12 months after instillation, were dried to a constant weight and were measured for hydroxypro-line concentration using chloramine - T method.2. Environmental mycological study and respiratory disease investigation in fur - processing workersSubjects: A total of 138 workers were investigated in this study. 27 male smoking workers were 32.6 yr old on average and the average work duration was 3. 1 yr, and 16 male non - smokers were 31. 6 yr old on average and average work duration was 5. 1 yr. 95 female workers (non - smoking) were 30.6 yr old and the average work duration was 4. 0 yr. Another 40 workers with no exposure to dust or toxicants were selected as controls. 12 male smokers were 31.8 yr old on average; 8 male non - smokers 32. 3 yr old on average; and 20 females (non - smoker) 30.1 yr old on average.Dust concentration, free silica content and environmental mycological stud-y: The arithmetic means of dust concentrations were calculated as the time -weighted average ( TWAs). The gravimetric method was carried out to analyze the silica content. Out - plate culture was adopted to inspect the fungus conditions in all workshops. The culture plates used contained Sabouraudæ‹¢ agar medi-jum. Five plates were exposed in the workers'breathing zone (1 -1.5 m high) for each processing workshop. Their fungus colonies were counted after being incubated at 25 - 28 C for 7 d. Species of isolated fungi were identified according to morphology under the microscope.Respiratory symptom investigation and chest X -ray examination; Data on respiratory symptoms and smoking habits were collected by means of a self - administered Chinese version of the British Medical Research Council (BMRC) Standardized Questionnaire. Chest X - ray films were taken for those with at least 3 respiratory symptoms. The films with spotted or patchy shadows or mediate or severe enhanced lung marking were considered to be abnormal.IgG to Fungi by Enzyme - linked immunosorbent assay: 5ml sera of 138 exposed workers and 40 control workers we...
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