Production of DDT-resistance in Bangkok strain of Cheopis fleas under laboratory conditions

Normal Bangkok strain of X. cheopis which had little resistance to DDT in 1966 became moderately resistant in 1972 without any direct exposure to the insecticide. It was analyzed that the causes of resistance gaining were as follows. First, the possibility of being exposed unconsciously to DDT spray under malaria eradication program could not be ruled out, even in laboratory as far as ventilation windows would be open sometime. Insecticides from air spray through the window influenced the fleas kept in the pools. Second, it may be said that initial resistance to DDT has become greater and greater ecologically without any exposure of insecticides. A highly resistant strain of X. cheopis which survived after contacting 4% DDT for five times during one year period was obtained in the laboratory and it showed 100% survival at the highest concentration (4%) of DDT paper by 24 hour exposure. The hybrid forms between normal Bangkok strain and artificially mutated "Resistant Strain" were obtained by mixing the above two colonies. Regardless to the sexes of both ancestors, the results of resistance tests of hybrids showed that artificially gained resistance of fleas to DDT was inherited possibly by recessive hereditary role by pheonotype.

A survey on the resistance of Vietnam fleas to some insecticides

The results of the tests carried out in 1971 strongly suggested that a considerable portion of the flea population in MR 2 had developed resistance not only against DDT but also malathion and dieldrin. There is also the possibility of the fleas developing a resistance to diazinon and lindane. Thus careful consideration should be given to the continuous use of diazinon. In areas where fleas had developed a resistance to malathion, further tests should be conducted continuously to confirm the possible development of resistance. Other insecticides which have not been used in Vietnam for any purpose should be ready to be substituted, if the development of resistance is confirmed.

Syhilis Screening Among some Industrial Workers in Korea / 예방의학회지

A study on the morbidity of syphilils among 729 workers on Po Hang and Ul San Industrial Complexes at the routine periodical examination was performed. In addition to the morbidity, factors related to the disease infection such as educational level, religion, preventive measures taken by the workers, history of urethritis, and so on were studied and analysed to check significant relation. The result were as follows. 1. VDRL and RPR tests were undertaken to determine the sensitivity and specificity of RPR tests which was utilized for all the workers studied. It related 86.4% of sensitivity and specificity 87.7% of specificity from the RPR tests, and 81.8% of sensitivity and 90.1% of specificity from the VDRL tests compared with RPCF test. There were 87.4% of agreement rate vetween RPR and VDRL. Actually, RPR was more sentitive but less specific than VDRL , and found to be a satisfactory screening test for syphilis especially in the fields. 2. Among the workers in Po Hang Area 24.0% of them revealed reactive result, and in Ul San Area 5.2% revealed result showing 4.6 times of risk among workers on Po Hang Area. 3. There were no statistically significant differences between RPR reactive rates and personal characteristics such as educational level, region, history of urethritis experience, history of coitus with prostitute, and preventive measures of V.D taken by workers of evaluated by area of Po Hang and Ul San separately. 4. V.D. could be encountered as an occupational disease in certain conditions of working places and the psychosocial problems of workers. And so, It is necessary that the workers working in special estates such as on Po Hang Industrial Complex should be checked to be screened out by RPR test at periodical examination also should include RPR test be compared with. Regardless of the workmen's compensation, establishment of V.D. treatment clinic of system for such industrial workers is urgently needed. Health education regarding V.D. is another subject to be performed.

An Analytical Study on Work Environments and Occupational Diseases in Korea(1987) / 대한산업의학회지

Health care management for industrial workers in Korea in terms of occupational health launched in 1953 when the Labour Act was enacted. Nevertheless, negligence of government on reality of workers health was said to be inevitable under the cloak of urgent fast development in way of industrialization. Happily, however, since 1981 when Industrial Safety and Health Law was enacted, periodical evaluation of work environment and physical check-up of workers have been worked out by several professional organizations under the umbrella of Korean Industrial Health Association. In 1986, for about 5,700 industries, a total of 125,000 checks of work environment including the agents of dust, noise, lead, organic solvents, special chemicals, and of others were carried out, and on the other hand, a total of 340,000 physical check-ups were performed in accordance with exposed hazardous agents in the work-lines. The summarized results of the above achievements were as follows. 1. The case detection rates of occupational diseases among workers in industries of Korea has been revealed to be half of Japanese ones since 1975 decreasing from 2.3% in 1975 to 1.7% in 1987. However, it is too hard to believe that the above detection rate which is lower than that of Japan indicates the real prevalence rate of occupational diseases among industrial workers of Korea. It may be underestimated by defects in management of health care system for workers in Korea. 2. A total of 6,942 cases (1.65%) of occupational diseases were detected through 421,019 spells of check-up from 345,780 industrial workers in 1987. Detection rate by industry was highest among coal mines and secondly highest among mines other than coal ones. 3. Detection rate by hazardous agent was highest among workers in relation to dust, and secondly highest to noise. Case detection rate in relation to organic solvent, lead, special chemicals and others was less than 0.1% in total, which is very low comparing with that in Japan. There should be some modification in the check-up management. 4. A total of 32,035 (25.5%) work points was found to be improper showing higher level of hazardous agent than the TLV. Actually, a total of 125,721 work points was evaluated from 5,695 industries. The rate of detecting improper environment was highest among mines other than coal mines. Second highest was in textile manufacturing industries. 5. Noise and dust are the typical agents of which levels in workplace were high in most of industries. Levels of organic solvents, lead, and others were higher than TLV in 9.5-17.0% of samples tested. 6. In relation to noise, the rate of noise level exceeding TLV was higher in mines and textile industries. However, there were less workers of hearing loss in textile industries. 7. In relation to dust, the rate of dust concentration exceeding TLV was higher in non-metal manufacturing industries and mines. However, the majority(92.0%) of pneumoconiosis were detected from workers of mines. Rare cases of pneumoconiosis were detected from workers of textile industries.

The Last Fifty Years of Western Medicine in Korea: The Korean Society of Occupational Medicine

No abstract available.

Discussion on the health Care System for Industrial Workers in Korea In relation to Revision of Industrial Safety and Health Law / 대한산업의학회지

No abstract available.

Health Screening for Peoples around Industrial Complexes

No abstract available.

Cohort Study / 한국역학회지

The cohort study is an observational epidemiological study which selects the specific study population attempting to study the relatiqnship between an exposure to the purported cause and the subsequent risk of developing disease in accordance of time direction. Since Doll and Hill had studied the association between lung cancer and smoking behavior among the British medical doctors in the years of the last fifties, the defined group cohort studies analysing the relationship between an exposure and the occurence of a disease have become very popular. Cohort studies can be classified as either prospective or retrospective, depending on the temporal relationship between the initiation of the study and the occurence of the disease. Cohort studies are admitted as the very valuable studies for demonstrating the association between an exposure and a disease because it is possible to drive relative and attributable risks and often incidence measures. They can even examine multiple effects of a single exposure. However, they are usually expensive to carry out and large cohorts are required for rare diseases in addition to the time consum ing works. There are also very significant problems associated with selection of appropriate groups to be studied as far as complete ascertainment of disease occurence in them. Usually it is necessary that we must compromise to provide the opportunity for various types of bias such as selection bias, follow-up bias, information bias or misclassification, confounding bias and post hoc bias to occur which can result in incorrect conclusions. Only the success of a cohort study would be expected when the investigator pay the deep care in recognizing and correcting for these biases.

A Study on the Activity of Erythrocyte Pryrimidine 5'-Nucleotidase in Workers Exposed to Lead / 대한산업의학회지

In this study, we measured the activity of the erythrocyte pyrimidine 5'-nucleotidase(P5N) for 83 workers exposed to lead in their workplace, and analyzed the correlation of the activity with other biological exposure indices of lead. The measurement was performed by using a high performance liquid chromatography (HPLC) with a reverse phased ODS column. The results are as follows; 1. The correlation of the erythrocyte P5N activity with the concentration of blood lead(PbB) was shown to be statistically significant (r=-0.71, p=0.0001). 2. For a group of subjects whose PbB was less than 10microgram/dl, the erythrocyte P5N activity was 14.9+/-1.5 micromole uridine/h/g Hb. 3. For medical surveillance, this study suggests the erythrocyte P5N activity of 12 micromole uridine/h/g Hb is equivalent to 40 microgram/dl of PbB. 4. The correlation coefficients of the erythrocyte P5N activity with other biological exposure indices of lead such as PbB, ZPP, ALA-U, PBU, CP-U, ALAD, and log ALAD were -0.71, -0.64, -0.57, -0.51, -0.50, 0.46 and 0.64, respectively. 5. The correlation coefficients of the PbB with other biological exposure indices of lead for ALAD, P5N, ZPP, PBU, CP-U, and ALA-U were -0.76, -0.71, 0.68, 0.59, 0.42, and 0.41, respectively. The erythrocyte P5N activity can be used as a reliable biological exposure index of lead.

A rural health study through screening approaches / 한국역학회지

No abstract available.

Study on the states of occupational health management about the subcontract company among the medium and small scale companies / 대한산업의학회지

No abstract available.

A Study on the Crops Pollution with Heady Metal / 예방의학회지

Certine heavy metals which may lead peoples to poisonous status are widely used in industry and their used have been increasing along with rapid industrialization of this country. Such an increasement of metal uses aggravates the status of environmental pollution affecting foodstuffs which are the most important life supporting factor of animal and human being. Concerning the safety measures to minimize food-borne transmission of such hazardous metals, surveillance is the backbone of them and probably more so with a potential problem such as intoxication. Theoretically, this surveillance should include the determination of levels of heavy metal toxicants in foods, the determination of food consumption patterns and typical total diet, and the estimation of total load the metal contaminant from all sources of exposure including air, water, and occupational sources. In recent year, actually, such estimates on the total daily intake of some heavy metals from foods have been made in several developed countries and a wide variation of date by season, locality, and research method was recognized. Also in this country, this kind of research data is vitally needed to make up for the serious shortage or lack of references to estimate the total amount of heavy metal intake of the people. In this study, a modification model for estimation of the total daily intake of cadmium copper, nickel, zinc, and lead through foods was applied and concentrations of the above metals in crops cultivated in this country were measured with atomic absorption spectrophotometer to get the following results. 1.Level of heavy metal concentration in crops. Generally, the levels of such metals in essential crops such as rice, cucumber, radish, chinese cabbage, apple, pear, grape, and orange are similar or lower than those in Japan and other developed countries. By the way, a striking result on cadmium concentration was increasement of its concentration in rice from 0-0.035ppm in 1970 to 0.11ppm in this study. However, the value is still far below the Japanese Permissible Level of 1.0ppm. 2. Estimation of total daily intake per from foods. A new model for estimation was devised utilizing levels of metal concentration in food, amount of food consumed, and other food factors. Based on the above method, the daily intake of cadmium was estimate to be 70.53 microgram/man/day in average which was as high as the Limit Value of ILO/WHO(up to 71.4 microgram/man/day). Also, 3.89mg of Zinc, 1.65mg of cuppor, 0.32mg of lead were given as the total daily intake per capita by this research. 3. Efficacy of washing or skinning to decrease the amount of metals in crops. After washing the crops sufficiently with commercial linear alkylate sulfonate, the concentration of heavy metals could bae reduced to 50-80% showing decreasement rate of 20-50%. Also, after skinning the fruits, decreasement rate of the heavy metal concentration showed 0-50%.

A study on the mercury contamination sources and risk for occupational mercury poisoning of mercury exposed workers in Korea / 대한산업의학회지

No abstract available.

Heart Diseases Prevalence of Elementary School Children in Kyonggi Province / 예방의학회지

OBJECTIVE: The heart diseases are known as a major cause of sudden death, as well as a cause of poor life-quality of school-age children. But there have been few mass screening of heart diseases in these children in Korea. This study was done to estimate the prevalence of heart diseases of these population. METHODS: We screened all elementary students(grade 1) in 12 cities and 16 counties(Gun) in Kyonggi province from 1992 to 1995. The first screening was done by auscultation of doctors and simultaneously by checking using 'auto-interpreter of EKG-cardiac sound'(Fukuda Densi ECP 50A). We conducted futher examinations to whom classified as being abnormal condition in first screening, by using EKG, chest x-ray, doppler echocardiograpy(if needed). RESULTS: The total number of examined students was 161,308(92% of the population), the male were 83,238 and female were 78,070. The congenital heart diseases(CHD) patients were 290(18 per 10,000) - male 155(18.6 per 10,000) and female 135(17.3 per 10,000). The most frequent disease was ventricula septal defect(VSD, 45.5%), Atrial septal defect(ASD, 14.8%), Tetralogy of Follot(TOF, 11.7%), and Patent Dutus Arteriosis(PDA, 7.6%) in order. In female, the order was VSD(48.1%), ASD(13.3%), TOF(11.1%), and PDA(10.4%). The total number of EKG abnormality were 433(62.7 per 10,000) among 69,056 screened children in 1995. The complete right bundle branch block(CRBBB) and paroxymal ventricular contraction(PVC) were frequent(26.6%, 26.3% in each), and incomplete right bunddle branch block(IRBBB,14.6%), paroxymal atrial contraction(PAC, 6.7%), abnormal Q(5.8%), Wolf-Pakinson-White syndrom (5.5%) in order. In female, the most frequent abnormality was PVC(29.8%), and CRBBB(19.9%) in order. CONCLUSION: We could present the stable prevalence of the rare heart disease. The prevalence of congenital heart diseases was 18.0 per 10,000 and of EKG abnormality was 62.7 per 10,000 among school children.

Clinical Analysis of 8 Cases of Chronic Carbon Disulfide Poisoning in Workers Engaged in the Viscose Rayon Industry / 대한산업의학회지

The authors have experinced 8 cases of chronic carbon disulfide poisoning in workers engaged in the viacase rayon industry during the period between March 1987 and September 1988. Cases of carbon disulfide poisoning has not been reported in Korea till then. Carbon disulfide is primarily a neurotoxic poison, therefore those symptoms indicating central and peripheral nervous damage are very important. And it has toxic effects on the various organs such as skin, eye, ear, and respiratory, cardiovascular, gastrointestinal, hepatic, genitourinary, hematological, and endocrine system. Occupational histories were obtained, and clinical findings and laboratory findings were analysed on all cases. 1. Seven (7) cases had been exposed to carbon disulfide for more than 10 years, and 1 case has been exposed for 6 years. 2. Most common symptoms were neurological symptoms such as gait disturbance, extremity weakness, paresthesia, and speech disturbance. 3. Involvement of central nervous system was noted in 7 cases through abnormal findings of electroencephalography, brain computerized tomography, neurological signs, and psychological test. Needle electromyography and nerve conduction study showed polyneuropathy in all cases. Ophthalmological abnormalities were found in 7 cases, mainly retinal microaneurysms and peripheral constriction of the visual field. Renal damage appeared in 4 cases, increase of serum cholesterol and/or triglyceride level appeared in 3 cases, and dercrease of erythrocyte and hemoglobin appeared in 2 cases. And hypertenison appeared in 2 cases, and diabetes appeared in 1 case. One(1) case who has been exposed tn carbon disulfide for 6 years showed polyneuropathy and peripheral constriction of the visual field.

The Study on the Relationships Between Inhalation Volume and Exposure Duration and Biological Indices of Mercury among Workers Exposed to Mercury / 예방의학회지

This study was conducted to evaluate the relationships between the environmental exposure and biological monitoring among workers exposed to metallic mercury. We interviewed each workers to get the medical history including previous hazardous occupational history we measured the respiration rate and tidal volume of each worker in order to calculate the 8-hour inhaled mercury of workers. And we wanted to evaluate the effect of exposure duration to mercury concentrations in blood and urine as biologic exposure indices of metallic mercury. The regression and correlation analysis were done to the relationships of 8-hour inhaled mercury are mercury in blood and urine. The results were as follows; 1. The subjects were 35 fluorescent lamp manufacturing workers. The mean age of subjects was 24.8 years old, and the mean work careers of workers was 1.19 years. 89% of the total was consisted man. 2. The correlation coefficients between 8-hour inhaled mercury and mercury in blood and urine were higher than that of only considered air mercury concentration. 3. The correlation coefficients of 8-hour inhaled mercury and mercury in blood and urine were above 0.9 in workers who had exposed to mercury more than 1 year. 4. The R-square value and -value of regression analysis between the 8-hour inhaled mercury and mercury inn blood and urine was also higher in workers who had exposed to mercury over 1 year than in workers who had less than 1 year working experience. The important results or this study were that relationships between the 8hr-inhaled mercury and mercury in blood and urine was very high than that with air mercury concentration only. And the results were very apparent when considering workers 1 year or more. Therefore we concluded that the work career and respiratory volume of each individuals should be considered in evaluation the results of biological monitoring of workers exposed to metallic mercury.

An Analytic Study on the Effect of Carbon Disulfide on the Blood Pressure / 예방의학회지

To investigate the effect of carbon disulfide on blood pressure, the BP measurements in the periodic health examination results and the medical records of factory clinic were reviewed The study subjects were composed of 1336 male and 544 female workers, who were categorized into three groups by the exposure status-highly exposed, moderately exposed and non-exposed group. The results of the study were as follows; 1. The age-adjusted mean systolic and diastolic BP of male workers were 122.35 mmHg/79.11mmHg in highly exposed, 121.57mmHg/79.05mmHg in moderately exposed and 122.67mmHg/82.27mmHg in non-exposed group. For female workers, BP were 115.13mmHg/74.49mmHg in moderately exposed and 113.48mmHg/74.30mmHg in non-exposed group. 2. In multiple regression analysis of maximum BP against Age and tenure, the slope coefficients of age and tenure on the systolic BP were 0.379, 0.667 respectively and those on the diastolic BP were 0.331, 0.405 respectively in highly exposed male workers. Tenure was a significant variable in this study. For female workers, however, the slope coefficients of tenure on BP were significant only for systolic BP of moderately- expected group. 3. In multiple regression analysis of Bp against age, cumulative exposure index(CEI), cholesterol, all the variables showed significant slope coefficients in male, but age and CEl on systolic BP were significant for female workers (P<0.05). 4. In the multiple analysis of the amount of Bp change and the velocity of Bp change among male workers, the slope coefficients of tenure tended to increase as exposure level increased. Among female workers, the slope coefficients of tenure were significant on the amount of Bp change and the velocity of Bp change in moderately exposed group.

Evaluation of Mercury Concentration in Spot Urine for Biological Monitoring Among Metallic Mercury Exposed Workers / 대한산업의학회지

Biological monitoring for exposures permits estimation of organ doses or body burdens from exposures through all relevant portals of entry. Biological monitoring data may be used to estimate environmental concentrations when the latter cannot be measured directly. Biological indices are usually surrogates for the concentration of a chemical or its metabolites or its effect at the true receptors. Mercury concentration in urine has-been most-coinmoialy-recommended as a biological exposure index of mercury. For data based on urine analysis, variation in urine volume is the most significant. The urinary concentration related to excretion of the solute provides some correction for fluctuation of urine output. Sampling time must be carefully observed because distribution and elimination of a chemical are kinetic events. This study has evaluated mercury concentration in spot urine compared to the results of 24 hour collected urine by the adjustment methods (specif ic gravity, creatinine) and sampling time. The subjects were 43 workers who had been exposed to the metallic mercury. The results were as follows: 1. The correlation coefficients between mercury concentration in 24 hour urine and that in spot urine were 0.639-0.715 and were not different by adjustment methods. 2. In the high exposure group who were over lOOug/1 of urinary mercury, the correlation coefficients between mercury concentration in 24 hour urine and that in spot urine were 0. 687-0.824 and were not different by adjustment methods. 3. Mercury concentration in spot urine were very variable by sampling time or exposure time. The correlation coefficients between mercury concentration in 24 hour urine and that in spot urine were most highest as 0.85-0.91 at first voiding urine in the morning, and were 0. 77-0.86 at urine collected within four hours before end of shift. In the biological monitoring to exposure of mercury, sampling of spot urine were most proper at first voiding urine in the morning, and then at urine collected within four hours before end of shift. But the adjustment methods of specific gravity and creatinine were no difference of the results.

Quantitative Sensory and Vascular Tests in the Assessment of Hand-Arm Vibration Syndrome / 대한산업의학회지

This study was conducted on 103 male workers exposed to local vibration (exposure workers) and 23 male clergical workers not exposed to local vibration (reference workers) to evaluate the effect of local vibration in a automobile industry workers who had used vibratory tools such as electric bolt impacter or grinder. The assessment methods of this study were some tests recommended by Wasserman and Taylor. None of reference workers complained sensorineural symptoms, but 43.7% of exposed workers complained over one of those symptoms. The proportion of non-recovery type, which means that there was no full recovery of temperature of finger tips, was from 0% to 31. 3% in reference workers and from 10.7% to 15.5% in exposure workers. There was statistically significant difference of recovery time of plethysmogram after cold provocation between mean recovery time of 0.44 minutes in reference workers and that of 3.05 minutes in exposure workers. The proportion of bad plethysmogram was from 0% to 4.4% in reference workers and from 3.9% to 7.8% in exposure workers. There was statistically significant difference of discrimination sense between mean length of 2.04 mm in reference workers and that of 2.9 mm in exposure workers. There were also statistically significant difference of pain sense between mean weights of from 5.02 g to 5.26 g in reference workers and those of from 6.81 g to 7.6 g in exposure workers. By the results of multiple stepwise regression analysis the statistically significant variable affecting discrimination and pain sense was exposure and those affecting vibration sense were exposure and age. We concluded that exposure of local vibration in automobile workers was significaritly associated with decrease of sensorineural sense regardless of age and other, possible related variables.

Quantitative Sensory and Vascular Tests in the Assessment of Hand-Arm Vibration Syndrome / 대한산업의학회지

This study was conducted on 103 male workers exposed to local vibration (exposure workers) and 23 male clergical workers not exposed to local vibration (reference workers) to evaluate the effect of local vibration in a automobile industry workers who had used vibratory tools such as electric bolt impacter or grinder. The assessment methods of this study were some tests recommended by Wasserman and Taylor. None of reference workers complained sensorineural symptoms, but 43.7% of exposed workers complained over one of those symptoms. The proportion of non-recovery type, which means that there was no full recovery of temperature of finger tips, was from 0% to 31. 3% in reference workers and from 10.7% to 15.5% in exposure workers. There was statistically significant difference of recovery time of plethysmogram after cold provocation between mean recovery time of 0.44 minutes in reference workers and that of 3.05 minutes in exposure workers. The proportion of bad plethysmogram was from 0% to 4.4% in reference workers and from 3.9% to 7.8% in exposure workers. There was statistically significant difference of discrimination sense between mean length of 2.04 mm in reference workers and that of 2.9 mm in exposure workers. There were also statistically significant difference of pain sense between mean weights of from 5.02 g to 5.26 g in reference workers and those of from 6.81 g to 7.6 g in exposure workers. By the results of multiple stepwise regression analysis the statistically significant variable affecting discrimination and pain sense was exposure and those affecting vibration sense were exposure and age. We concluded that exposure of local vibration in automobile workers was significaritly associated with decrease of sensorineural sense regardless of age and other, possible related variables.