Association between endotoxin levels in dust from indoor swine housing environments and the immune responses of pigs

Indoor animal husbandry environments are inevitably contaminated with endotoxins. Endotoxin exposure is associated with various inflammatory illnesses in animals. This cross-sectional study evaluated the relationship between the degree of endotoxin exposure and the cellular and humoral immune profiles of fattening pigs. Blood samples were taken from the jugular vein of 47 pigs from ten pig farms in Korea. Whole blood cell counts and plasma immunoglobulin (Ig) classes were determined. Peripheral-blood mononuclear cells were stimulated in vitro with concanavalin A for 48 h, and cytokines released into culture supernatants were measured. The barns in which the pigs lived were assessed for endotoxin levels in the total and respirable dust by using the limulus amebocyte lysate kinetic QCL method. Low and high endotoxin exposures were defined as ≤ 30 and > 30 EU/m³, respectively. Compared to pigs with low endotoxin exposure (n = 19), highly exposed pigs (n = 28) had higher circulating neutrophil and lymphocyte (particularly B cells) counts, IgG and IgE levels, interferon-gamma (IFNγ) and interleukin (IL)-4 productions, and lower IgA levels and tumor necrosis factor-alpha (TNFα) production. The IL-4, IFNγ, and TNFα levels significantly correlated with endotoxin level and/or pig age. Constant exposure of pigs to high levels of airborne endotoxins can lead to aberrant immune profiles.

Epizootiological characteristics of viable bacteria and fungi in indoor air from porcine, chicken, or bovine husbandry confinement buildings

Microorganisms found in bioaerosols from animal confinement buildings not only foster the risk of spreading diseases among livestock buildings, but also pose health hazards to farm workers and nearby residents. This study identified the various microorganisms present in the air of swine, chicken, and cattle farms with different kinds of ventilation conditions in Korea. Microbial air samples were collected onto Petri dishes with bacterial or fungal growth media using a cascade impactor. Endotoxin levels in total dust were determined by the limulus amebocyte lysate kinetic QCL method. Prevalent Gram-positive bacteria were Staphylococcus (S.) lentus, S. chromogenes, Bacillus (B.) cereus, B. licheniformis, and Enterococcus faecalis, while the dominant fungi and Gram-negative bacteria were Candida albicans and Sphingomonas paucimobilis, respectively. Considering no significant relationship between the indoor dust endotoxin levels and the isolation of Gram-negative bacteria from the indoor air, monitoring the indoor airborne endotoxin level was found to be also critical for risk assessment on health for animals or workers. The present study confirms the importance of microbiological monitoring and control on animal husbandry indoor air to ensure animal and worker welfare.

Relationship between chicken cellular immunity and endotoxin levels in dust from chicken housing environments

Hazardous biochemical agents in animal husbandry indoor environments are known to promote the occurrence of various illnesses among workers and animals. The relationship between endotoxin levels in dust collected from chicken farms and various immunological markers was investigated. Peripheral blood was obtained from 20 broiler chickens and 20 laying hens from four different chicken farms in Korea. Concentrations of total or respirable dust in the inside the chicken farm buildings were measured using a polyvinyl chloride membrane filter and mini volume sampler. Endotoxin levels in the dust were determined by the Limulus Amebocyte Lysate Kinetic method. Interferon-gamma production by peripheral blood mononuclear cells stimulated with concanavalin A was significantly lower in broilers or layers from the farms with higher endotoxin concentrations than the chickens from the farms with lower endotoxin levels. An opposite pattern was observed for plasma cortisol concentrations with higher cortisol levels found in chickens from the farms with higher endotoxin levels. When peripheral lymphocytes were examined, the percentage of CD3-Ia+ B cells was lower in layers from farms with higher endotoxin levels than those from locations with lower endotoxin levels. Overall, these results suggest a probable negative association between dust endotoxin levels and cell-mediated immunity in chickens.

The Relationship between Long Working Hours and Industrial Accident / 한국직업건강간호학회지

PURPOSE: This study analyzed the relationship between working hours and the occurrence of industrial disasters based on manufacturing businesses that are members of Federation of Korean Trade Unions. METHODS: Repliers were managers of the safety & health department in the union, and 215 surveys out of 300 businesses that agreed to participate in the research were analyzed. RESULTS: 94 out of 300 companies, which counted for 43.7%, replied to have experienced industrial disasters. 56 of those (59.6%) had less than 52 working hours per week, and 38 companies (40.4%) had more than 52 working hours per week. 109 companies, which counted for 50.7%, did not have an incident of industrial disaster. Companies with an average of more than 52 hours of working hours per week were shown to have a 2.29 times (95% CI 1.08~4.87) higher possibility of having industrial disasters than those with less than 52 hours of working hours. CONCLUSION: As the study showed that industrial disasters were more likely to occur in businesses with working hours longer than 52 hours, ways to reduce working hours need to be developed and various safety measures need to be taken to prevent industrial disasters in case workers are undergoing long working hours.

The Relationship between Long Working Hours and Industrial Accident / 한국직업건강간호학회지

PURPOSE: This study analyzed the relationship between working hours and the occurrence of industrial disasters based on manufacturing businesses that are members of Federation of Korean Trade Unions. METHODS: Repliers were managers of the safety & health department in the union, and 215 surveys out of 300 businesses that agreed to participate in the research were analyzed. RESULTS: 94 out of 300 companies, which counted for 43.7%, replied to have experienced industrial disasters. 56 of those (59.6%) had less than 52 working hours per week, and 38 companies (40.4%) had more than 52 working hours per week. 109 companies, which counted for 50.7%, did not have an incident of industrial disaster. Companies with an average of more than 52 hours of working hours per week were shown to have a 2.29 times (95% CI 1.08~4.87) higher possibility of having industrial disasters than those with less than 52 hours of working hours. CONCLUSION: As the study showed that industrial disasters were more likely to occur in businesses with working hours longer than 52 hours, ways to reduce working hours need to be developed and various safety measures need to be taken to prevent industrial disasters in case workers are undergoing long working hours.

Factors Associated with Performance of Occupational Health Services in Small-sized Workplaces / 한국직업건강간호학회지

PURPOSE: This study is to identify factors associated with performance of occupational health services in small-sized workplaces in Korea. METHODS: The data were collected from a random sample of 1,158 occupational health managers working for small-sized workplaces across the nation in which occupational health services were supported by Korean Industrial Health Association. A structured questionnaire was self-administrated by occupational health managers about characteristics of workplaces, occupational health managers, and performance level of occupational health services. RESULTS: Stepwise multiple regression analyses revealed that factors associated with performance of occupational health services in small-sized workplaces included supervisor being designated, occupational health manager having received safety and health training, and employer's concern with activities of health management. CONCLUSION: Government should make efforts to raise the level of employer's concern to occupational health activities. And it is needed to promote health managing staff as a core personnel to self-management for occupational health system.

A Validation of the Korean Version of QEESI(c) (The Quick Environmental Exposure and Sensitivity Inventory) / 대한산업의학회지

OBJECTIVES: A standardized questionnaire is not available for use as a screening tool to assess individuals with MCS/IEI in Korea. The QEESI(c), originally developed by Miller & Prihoda in 1998, helps researchers, doctors, and their patients identify individuals with MCS/IEI. Therefore, this study was conducted in order to create a Korean version of the QEESI(c) and evaluate whether this Korean version could be used as an effective MCS/IEI screening tool in Korea. METHODS: The Korean version of the QEESI(c) was developed using a six-step approach: permission, forward translation, the first quality control, backward translation, cognitive debriefing and the second quality control, final proof reading. In order to collect data, we have done a sample survey in certain parts of Korea. A household was used as the sampling unit; we extracted random samples in each survey cluster and then interviewed two adults over 19 years of age living in each sampled household. A total of 300 subjects were recruited from the general population in local community. The factor structure in the Korean version of the QEESI was analyzed with 40 items on four sub-scales except for the 10 items in masking index using principal components analysis with Varimax rotation. A convergent validity test two sub-scales: chemical intolerance and symptom severity. We carefully compared the chemical intolerance with Nordin's chemical sensitivity scale and the symptom severity with Cho's subjective symptom score. RESULTS: The results showed that the 40 items on the four sub-scales,' chemical intolerances',' symptom severity', 'life impact', and 'other intolerances', were consistent with those reported for the US population by Miller and Prihoda. The convergent validity wes very good (r=0.4; p<0.001, r=0.5; p<0.001, respectively). A good internal consistency (Cronbach' alpha=0.86~0.96) and test-retest reliability (r=0.87~0.90) were found in all scales, except for the internal consistency in the masking index. CONCLUSIONS: The Korean version QEESI(c) showed a good reliability and validity. It should be necessary to conduct a MCS/IEI study adopting Korean version QEESI(c).

Factors Associated with Performance of Occupational Health Services in Small-sized Workplaces / 산업간호학회지

PURPOSE: This study is to identify factors associated with performance of occupational health services in small-sized workplaces in Korea. METHODS: The data were collected from a random sample of 1,158 occupational health managers working for small-sized workplaces across the nation in which occupational health services were supported by Korean Industrial Health Association. A structured questionnaire was self-administrated by occupational health managers about characteristics of workplaces, occupational health managers, and performance level of occupational health services. RESULTS: Stepwise multiple regression analyses revealed that factors associated with performance of occupational health services in small-sized workplaces included supervisor being designated, occupational health manager having received safety and health training, and employer's concern with activities of health management. CONCLUSION: Government should make efforts to raise the level of employer's concern to occupational health activities. And it is needed to promote health managing staff as a core personnel to self-management for occupational health system.

Effects of Respirator Use Evaluated by Urinary Hippuric Acid Concentration in Toluene-Exposed Workers / 대한산업의학회지

OBJECTIVES: This study was carried out in order to raise workers'recognition of the effects of respirator use by providing concrete and practical data. METHODS: Twenty-six workers who dealt with toluene based ink and diluents at a gravure printing office in Seoul were investigated. The toluene exposure level and urinary hippuric acid level were monitored under respirator non-wearing(RNW) and under respiratory wearing(RW) conditions. RESULTS: The mean concentrations of toluene exposed to each worker through the air of gravure printing office were 147.52+/-57.34 and 134.55+/-52.44 ppm on respirator non-wearing day and respirator wearing day, respectively. There was no significant difference in toluene exposure concentration for the two days. The mean concentration of urinary hippuric acid in RNW and RW groups were 1.51 (0.53) g/L and 0.49 (0.14) g/L, respectively, as measured at the end of the workday. There was a significant difference seen in urinary hippuric acid concentration between the two days. The urinary hippuric acid concentration began to increase at 4 hours after the start of the workday(13:00) in RNW. However, there was no significant increase until the end of the workday in the case of RW. The urinary hippuric acid concentration in RW reduced 89.3% as compared with the concentration seen in RNW. There was a significant correlation between the toluene concentration and the urinary hippuric acid concentration in RNW. The regression equation was Y (urinary hippuric acid concentration, g/L) = 0.007 X x(toluene concentration in the air, ppm) + 0.665. CONCLUSIONS: Our results indicate that the respirator intercepted most toluene that may have been absorbed into the respiratory organs, and suggested that properly wearing a respiratory such as wearing the respirator during the entire workday and performing a proper fit test played an important role in the protection from toluene exposure

Effects of Stem Cell and Myeloperoxidase on Sister Chromatid Exchanges and Micronuclei Induction of Peripheral Lymphocytes by Styrene, Hydroquinone and Trichloroethylene / 대한산업의학회지

OBJECTIVES: The objective of this study was to identify the possible role of stem cell and myeloperoxidase (MPO) in the metabolic activation of styrene, hydroquinone and trichloroethylene, by investigating the effects of stem cell from umbilical cord blood and MPO on the frequency of sister chromatid exchange (SCE) and micronuclei (MN) induction in cultured human peripheral lymphocytes exposed to these chemicals. METHODS: Isolated lymphocytes from whole blood were cultured for 72 hours. The cells were treated with 1.50 mM styrene, 50 microM hydroquinone and 1.50 mM trichloroethylene dissolved with acetone (30 microl in total volume) at 24 hours after the beginning of culture. Control group was treated with acetone only. Immediately after adding these chemicals, 1.3X1 06 cells/ml and 2.6X1 06 cells/ml stem cell or 1.0 and 2.0 unit MPO with H2O2 (for substrate) were added to the cultures. Slides were stained with Giemsa's solution, and acridine orange for sister chromatid exchange, and for micronucleus analysis, respectively. RESULTS: The results were as follows: 1) Myeloperoxidase and stem cell did not significantly affect the frequencies of SCE or MN in the control group. 2) The frequency of SCE or MN with exposure to styrene did not different from control in the absence of stem cell or MPO. Sister chromatid exchange induced by styrene was significantly increased by adding stem cell or MPO in dose-dependent relationship. The frequency of MN induced by styrene significantly increased in the presence of 2.0 unit MPO. 3) The frequency of SCE was significantly increased with exposure to hydroquinone than acetone treated control in the absence of stem cell or MPO. Sister chromatid exchange induction by hydroquinone significantly increased dose-dependently in the presence of stem cell or MPO. There was a tendency of increase of the MN frequency induced by hydroquinone in the presence of stem cell or MPO, but not significant. 4) It was found that trichloroethylene itself did not increase SCE or MN frequency. Frequency of SCE induced by trichloroethylene was significantly increased with adding stem cell (low and high) and 2.0 unit MPO. Even though stem cell or MPO increased the frequency of MN of lymphocyte exposed to trichloroethylene, the difference was not significant. CONCLUSIONS: Authors found that the frequencies of both sister chromatid exchange and micronucleus induced by styrene, hydroquinone, and trichloroethylene were increased significantly with the treatment of stem cell or myeloperoxidase. It was suggested that myeloperoxidase may therefore play an important role in the metabolic activation of styrene, hydroquinone, and trichloroethylene and myeloperoxidase probably be involved in the myelotoxicity of these chemicals.

The Relationship Between Hippuric Acid in Blood Plasma and Toluene Concentration in the Air of Workplace / 예방의학회지

OBJECTIVES: This study was undertaken to evaluate correlation between the levels of hippuric acid in blood plasma (HAP) and those of toluene concentration in the workplace air. METHODS: Study subjects were composed of two groups; 21 workers who were occupationally exposed to toluene and 25 rural-area residents who were not exposed to any known occupational toluene source, as an exposed group and a reference group, respectively. Mean age and work duration of the exposed was 42 years and five years, respectively. Mean age of the reference was 42 years. To determine toluene concentrations in the workplace air, air sampling has been conducted for more than six hours using a personal sampler, and analyzed by a gas chromatography-flame ionization detector. Concentrations of hippuric acid in biological samples were determined by a high performance liquid chromatography-ultraviolet detector. RESULTS: Geometric mean(geometric standard deviation) of HAP and hippuric acid in urine(HAU) for the exposed was 1.39(2.21) mg/L and 2.77(1.46) g/L, respectively, which were significantly different from those of the reference [HAP, 0.45(2.94); HAU, 0.37(0.45)]. Toluene concentration in the workplace air was 86.92(range: 45.18~151.23) ppm. The level of HAP or HAU was significantly correlated (r=0.70 and r=0.63, respectively) with that of toluene in the workplace air. The estimated regression equation was logHAP(mg/L)=-3.60+1.93 log(toluene, ppm) or logHAU(g/L)=-0.85+0.67 log(toluene, ppm). The magnitude of correlation was further enhanced when analyzing relationship between toluene concentrations lower than 100 ppm and its corresponding HAP levels. CONCLUSION: Overall, plasma hippuric acid levels were well correlated with toluene concentrations in the workplace air, and a statistically significant correlation was observed for the samples with toluene concentration lower than 100 ppm.

A Forecasting Model for the Epidemic of Nationally Notifiable Communicable Diseases in Korea / 한국역학회지

PURPOSES: The authors derived two forecasting models which can be used as objective tools for detecting epidemics and predicting the future frequencies of communicable diseases. METHODS: In this study, regression analysis using trigonometric functions, Box and Jenkins's seasonal ARIMA model were applied to the monthly accumulated data of five nationally notifiable communicable diseases from January 1987 to December 1998 in Korea. RESULTS: Between two forecasting models, seasonal ARIMA model gives more precise predicted frequencies than regression model in the neighborhood of the current time points and future time, but the regression model is better in overall agreement between the predicted and observed frequencies during 7 years(1992-1998). CONCLUSIONS: These forecasting models can be usefully applied in deciding and carrying out a national policy in preventing epidemics in the future, and graphic program is much helpful to understand the present status of disease occurrence.

Performances of the WHO Neurobehavioral Core Test Battery among Mal Workers Occupationally Non-exposed to Neurotoxic Agents / 대한산업의학회지

Five items among neurobehavioral core test battery of World Health Organization, including Santa Ana dexterity, pursuit aiming, digit symbol, simple reaction time, and Benton visual retention, were administered to the workers occupationally non-exposed to neurotoxic agents by operational guide for the WHO neurobehavioral core test battery. Subjects were volunteers from the industrial workers (117) and clerks (40). Detailed occupational history such as exposed agents including noise or vibration, educational level, residence, smoking and drinking habit were recorded. Most of the neurobehavioral tests were correlated with age and educational level. Smoking was correlated with pursuit aiming and digit symbol. Vibration affected pursuit aiming. Job type (industrial workers vs. clerks) and noise exposure did not affected among tested items. Multiple regression analysis was done for establishing predict equation to estimate normal ranges of the tests for male workers. Age was shown to be main independent variable affected for all tests except wrong dot of pursuit aiming. Educational level was also shown to affected most of the tests except Santa ana dexterity and wrong dot of pursuit aiming. Alcohol consumption affected Santa Ana dexterity, non-preferred hand, and smoking affected only wrong dot of pursuit aiming after multiple regression analysis.

Performance Ranges of the Neurobehavioral Core Test Battery among Female Workers Occupationally Not Exposed to Neurotoxic Agents in Manufacturing Industries / 예방의학회지

With increased use of neurotoxic agents in manufacturing industries, hazardous effects of neurotoxic agents pose significant problems in protecting health of workers who work in these industries. A normal range of neurobehavioral performance is required 10 study hazardous effects of neurotoxic agents among workers. However, such reference for Korean population is not available yet. The objective of this study is to estimate a normal range of neurobehuvioral test performance of female workers in Korea. Data for neurobehavioral test performance developed by the world Health organization were obtained from 165 female workers. Study Subjects, 140 production workers and 25 clerks, who voluntarily participated in this study were not occupationally exposed to neurotoxic agents. The mean age and the mean education years of them were 32 years and 10.9 years, respectively. Santa Ana dexterity, pursuit aiming, digit symbol, simple reaction time, and Benton visual retention tests among the Neurobehavioral Core Test Battery(NCTB) were included in the evaluation. Subjects were interviewed by a trained interviewer for their detailed occupational history. Mean(+/-SD) performance of the participants were: 45.7+/-7.1 and 41.9+/-6.4 in the Santa Ana dexterity test of the preferred and non-preferred hands; 191.9+/-38.6 in correct dot of the pursuit aiming test; 57.7+/-16.0 in the digit symbol test; 274.8+/-44.6 msec in the mean simple reaction time and 70.5+/-69.0 msec in the mean standard deviation of it; and 7.8+/-1.7 in the Benton visual retention test. Most neurobehavioral performance scores were correlated significantly with age and educational level. Educational level was found to be a significant independent variable which was associated with all test scores. Age was significantly associated with scores of pursuit aiming and digit symbol tests.

Current Medical Exantination Practiees for the Determination of Occupational Noise Induced Hearing Losses / 대한산업의학회지

Occupational hearing loss became the leading occupational disease by constituting 56% of all work-related diseases in Korea. However, the prevalence rates showed wide variations among the specific medical examination providers (SHFEPs) and were very low (0.8-1.4%) compared with those of 8.4% in Japan. This study was designed to identify sources of these variations by inyestigating current audiometric testing methods and the diagnostic criteria utilized by the ShfEPs. A questionnaire was distributed to each of 27 SMEPS selected from total 70 SMEPS. Among them, 20 ShfEPs were interviewed and the rest of them were given the questionnaire from by mail. Included in the survey from were questions concerning audiometric testing methods and procedure equipment, facility personnel and the diagnostic criteria utilized, The results were as follows: 1. Employee audiometric testings were primaTily conducted by nurses and nurse-aids who had formal training for audiometry because no training program had been established. No requirement about the quality of audiometric testing personnel was specified in the regulation. 2. Although audiometric testing equipment used by the SDfEPs should be periodically calibrated, a significant number of them were not properly calibrated. Most of the calibration services were provided by the outside contractors and were done with no uniformly established periods. No SMEPS conducted the daily functional calibration. Most of the ShfEPs did not keep their calibration records. 3. Initial audiometric testings were conducted at any available spaces in the workplace or at the testing room without considering noise level in that place. Follow-up audiometric testings were also provided without considering the worker's noise exposure. Although audiometric booths were used during tHe follow-up testinga most of them did not meet the ANSI noise reauirement for audiometric booths. 4. AltHough a standard diagnostic criterion was promulgated in the law, the criterion was not used uniffrmly by the SMEPs. In addition, some SMEPS were applying age corrections which were not incorporated into the regulation yet. Therefore wide range of prevalence in NIHU among SMEPS could have possibly been caused by variable audiometric testing procedures and methods. In conclusion, it was recommended that systematical and general measures, such as formal and regular training program for testers, quality control regulation of instnlment calibration, and establishment of standard diagnostic criteria, be established for solving current problems and assuring equity among SMEPs in diagnosing occupational hearing losses.

Health Classification of Workers in Special Medical Examinations / 대한산업의학회지

The findings of special medical examinations are not infrequently summarized in the form of health classification. This procedure seems valuable for the protection of workers'health from personal health as well as public health point of view, because health classification of workers provides occupations health workers with birds eye view informations in terms of medical, placement and educational procedures, which are to be followed after medical examinations. In this study, the authors have reviewed the existing systems of special medical examinations and Health classifications in different countries and those recommended by international organizations for the purpose of improving the current system in Korea. The important issues covered in this review in relation to health classification of workers included the categories of diseases, the examination and laboratory tests, the criteria for health level classification and the health instructions to be given at each health levels. It was found that the current health classification system in Korea could be featurea as follows : 1. Special medical examinations are always carried out in combination with general medical examinations, contributing to the detection of risk factors of occupational diseases. 2. The selection of examinees is always made on the basis of work environment monitoring, often resulting in the underdetection of exposed workers. 3. Even if the test items are properly selected according to the principles of occupational medicine, further review is required in the light of recent advances in the pathogenesis as well as early changes of occupational diseases and epidemiologic principles. 4. The criteria for the classfication of health levels are to be reviewed on the basis of clinical epidemiology. 5. The health instructions covered only medical and placement aspects, failing to introduce the concept of health promotion.