Impact of Exposure to Dim Light at Night on Sleep in Female and Comparison with Male Subjects

OBJECTIVE: Light pollution has become a social and health issue. We performed an experimental study to investigate impact of dim light at night (dLAN) on sleep in female subjects, with measurement of salivary melatonin. METHODS: The 25 female subjects (Group A: 12; Group B: 13 subjects) underwent a nocturnal polysomnography (NPSG) session with no light (Night 1) followed by an NPSG session randomly assigned to two conditions (Group A: 5; Group B: 10 lux) during a whole night of sleep (Night 2). Salivary melatonin was measured before and after sleep on each night. For further investigation, the female and male subjects of our previous study were collected (48 subjects), and differences according to gender were compared. RESULTS: dLAN during sleep was significantly associated with decreased total sleep time (TST; F=4.818, p=0.039), sleep efficiency (SE; F=5.072, p=0.034), and Stage R latency (F=4.664, p=0.041) for female subjects, and decreased TST (F=14.971, p<0.001) and SE (F=7.687, p=0.008), and increased wake time after sleep onset (F=6.322, p=0.015) and Stage R (F=5.031, p=0.03), with a night-group interaction (F=4.579, p=0.038) for total sample. However, no significant melatonin changes. There was no significant gender difference of the impact of dLAN on sleep, showing the negative changes in the amount and quality of sleep and the increase in rapid eye movement (REM) sleep in the both gender group under 10 lux condition. CONCLUSION: We found a negative impact of exposure to dLAN on sleep in female as well as in merged subjects. REM sleep showed a pronounced increase under 10 lux than under 5 lux in merged subjects, suggesting the possibility of subtle influences of dLAN on REM sleep.

DNA Damage in Lymphocytes after Hair Dyeing and Related Factors among Women Volunteers / 예방의학회지

OBJECTIVES: To evaluate the DNA damage by hair dyeing in human lymphocytes. METHODS: Comet assays were carried out to evaluate the DNA damage in lymphocytes by hair dyeing. Twenty subjects were selected from women volunteers whose age ranged from 55 to 67 year old. All subjects had no smoking history. Blood samples were collected before and 6 hours after hair dyeing. DNA damage was evaluated by means of the tail moments, which were quantified by a KOMET 4.0 image analysis system. RESUJLTS: The tail moments before hair dyeing showed no significant differences among subjects except for the high frequency group. The mean values of the tail moments in subjects with low and high frequencies of hair dyeing were 1.39 and 1.77, respectively (p<0.05). The tail moments after hair dyeing increased significantly. The mean values of tail moments in subjects before and after hair dyeing were 1.45 and 1.79, respectively (p<0.01). However, the difference levels of DNA damage in lymphocytes before and after hair dyeing were found to be slightly lower in both the dietary supplement taking group and high frequency group. CONCLUSIONS: The high frequency group appears to have a higher level of DNA damage than the low frequency group before hair dyeing. DNA damage in lymphocytes was found to be significantly higher in the volunteers after hair dyeing. In this study, the related factors such as high frequency and taking dietary supplements appeard to reduce DNA damage in lymphocytes after hair dyeing.

DNA Damage in Lymphocytes after Hair Dyeing and Related Factors among Women Volunteers / 예방의학회지

OBJECTIVES: To evaluate the DNA damage by hair dyeing in human lymphocytes. METHODS: Comet assays were carried out to evaluate the DNA damage in lymphocytes by hair dyeing. Twenty subjects were selected from women volunteers whose age ranged from 55 to 67 year old. All subjects had no smoking history. Blood samples were collected before and 6 hours after hair dyeing. DNA damage was evaluated by means of the tail moments, which were quantified by a KOMET 4.0 image analysis system. RESUJLTS: The tail moments before hair dyeing showed no significant differences among subjects except for the high frequency group. The mean values of the tail moments in subjects with low and high frequencies of hair dyeing were 1.39 and 1.77, respectively (p<0.05). The tail moments after hair dyeing increased significantly. The mean values of tail moments in subjects before and after hair dyeing were 1.45 and 1.79, respectively (p<0.01). However, the difference levels of DNA damage in lymphocytes before and after hair dyeing were found to be slightly lower in both the dietary supplement taking group and high frequency group. CONCLUSIONS: The high frequency group appears to have a higher level of DNA damage than the low frequency group before hair dyeing. DNA damage in lymphocytes was found to be significantly higher in the volunteers after hair dyeing. In this study, the related factors such as high frequency and taking dietary supplements appeard to reduce DNA damage in lymphocytes after hair dyeing.

A Comparative Study of Item Analysis by Item Response Theory Based for Initiating CAT(Computer Adaptive Test) System / 한국의학교육

Prior to CAT, the parameter estimation on executed items should be accomplished by IRT.and the item banking must be build up on the basis of the parameter of difficulty. A program developed by Korea ETS Inc, Bilog and Bigsteps were all found to be very powerful to understand the attributes of items. Though multiple true-false type K items have some merits, the items should be examined quantitatively if they are appropriate or not by IRT. Through the study we have finally confirmed that the new program developed by Korea ETS has its ability to check the validities of items from preparing or scoring to item analysis.

Olfactory Function in Chromium Exposed Workers Without Nasal Septum Perforation / 대한산업의학회지

OBJECTIVES: The chrome-induced olfactory alterations is caused by inhalation of chromic acid, a highly corrossive and toxic materials. And nasal septum perforation(NSP) has been suspected with possible causative factor of olfactory alterations. To our knowledge, there has been no report of the detailed findings of the olfactory alterations in chrome exposed subjects without nasal septum perforation(NSP). So we present the results of olfactory function test measured by T&T olfactometer and olfactometer perception test among chromium exposed workers without NSP. METHODS: We performed this study in 25 study subjects and 25 control subjects matched with age, alcohol and smoking. All of subjects are man. We performed olfactory function test measured by T&T olfactometer and olfactometer perception test. RESULTS: 1) The age distribution of the subjects involved in this study was from 20 to 54 years old (average 33.3 years old) and the mean duration exposed to chromium was from 64. 9 months. 2) The olfactory function was checked by detection and recognition thresholds in five odorants. The detection thresholds of exposed group dealing with chromium were significantly increased in A and B ordorants than nonexposed group. The recognition thresholds of exposed group were significantly increased in D ordorants than nonexposed group. 3) The mean threshold of olfactometer perception test of exposed group were more increased than nonexposed group. But thresholds difference did not show statistical significance, 4) The detection thresholds of A and D ordorants, recognition threshold of C ordorants and thresholds of olfactometer perception test were increased in the relation with duration of chrome exposure. CONCLUSIONS: There has been no remarkable alterations in olfactory sense (TkT olfactometer and Olfactometer Perception Test) in subjects without nasal septum perforation(NSP) exposed to chromic acid.

A Field Efficacy Trial of Inactivated Hantaan Virus Vaccine (Hantavax(TM)) Against Hemorrhagic Fever with Renal Syndrome (HFRS) in the Endemic Areas of Yugoslavia from 1996 to 1998

In Yugoslavia, homorrhagic fever with renal syndrome (HFRS) is one of the important national health problem, but no vaccine has been used to prevent HFRS. Since first HFRS case in 1952, sporadic cases of HFRS occurred every year and over 4,000 registered cases with 1~16% mortality so far. We performed a prospective, randomized double-blind placebo-controlled trial to evaluate the effectiveness of Hantavax(TM) against HFRS in 3,900 healthy adults living in the endemic areas of Yugoslavia. 1,900 people were given 0.5 ml of Hantavax subcutaneously twice at one month interval and a booster shot at one year after. For controls other 2,000 healthy people were given 0.5 ml of physiolosical saline as a placebo. We investigated HFRS cases in both the vaccinated and nonvaccinated groups by monitoring the program for patient registration in the areas from 1996 to 1998, and the effect of vaccine was analyzed epidemiologically No confirmed case of HFRS was observed among 1,900 Hantavax vaccinees, while 20 confirmed cases were observed among 2,000 nonvaccinated control group. There were no remarkable side effects among the vaccinees either locally or in general after inoculation of the vaccine. The Hantavax vaccine showed statistically significant protective efficacy against HFRS among Yugoslavian people.

A Field Efficacy Trial of Inactivated Hantaan Virus Vaccine (Hantavax(TM)) Against Hemorrhagic Fever with Renal Syndrome (HFRS) in the Endemic Areas of Yugoslavia from 1996 to 1998

In Yugoslavia, homorrhagic fever with renal syndrome (HFRS) is one of the important national health problem, but no vaccine has been used to prevent HFRS. Since first HFRS case in 1952, sporadic cases of HFRS occurred every year and over 4,000 registered cases with 1~16% mortality so far. We performed a prospective, randomized double-blind placebo-controlled trial to evaluate the effectiveness of Hantavax(TM) against HFRS in 3,900 healthy adults living in the endemic areas of Yugoslavia. 1,900 people were given 0.5 ml of Hantavax subcutaneously twice at one month interval and a booster shot at one year after. For controls other 2,000 healthy people were given 0.5 ml of physiolosical saline as a placebo. We investigated HFRS cases in both the vaccinated and nonvaccinated groups by monitoring the program for patient registration in the areas from 1996 to 1998, and the effect of vaccine was analyzed epidemiologically No confirmed case of HFRS was observed among 1,900 Hantavax vaccinees, while 20 confirmed cases were observed among 2,000 nonvaccinated control group. There were no remarkable side effects among the vaccinees either locally or in general after inoculation of the vaccine. The Hantavax vaccine showed statistically significant protective efficacy against HFRS among Yugoslavian people.

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.

Vibration Perception Threshold of Male Workers Exposed to Carbon Disulfide / 대한산업의학회지

This study was conducted on 367 male workers to evaluate the change of vibration perception threshold (VPT) according to exposure degree to carbon disulfide. VPT was measured on both metacarpal bones of index and little fingers and on fibular malleoli by Vibrometer (Rion, on 125Hz). The exposure degree was classified by the name of department. Workers in department 1 had been exposed to high concentration of carbon disulfide, those in. department 2 had been exposed to carbon disulfide moderately or intermittently, and those in department 3 had been exposed to undetectable concentration of carbon disulfide. The results were as follows: 1. The mean values of VPT of metacarpal(MC) bones showed dose-response pattern, i.e., the mean values of VPT at department 1 were highest, and those of VPT at department 3 were lowest with similar work duration or age. But the mean values of VPT of fibular malleoli (FM) showed dose-response pattern only in workers having above 5 years of work duration or whose age were above 30. 2. The mean values of VPT of MC bone of workers increased by age. 3. There were statistically significant difference in mean values of VPT of MC bone only in workers having 5-10 year work duration. And there were statistically significant difference of mean values of VPT of left 2nd and 5th MC bone in workers whose age was 30's, of right 2nd MC bone in those whose age was 40's, and of left 2nd MC bone in those whose age was 50's. 4. The variables affecting VPT significantly were department and age (or age group) both in multiple regression and general linear model. The department showed to have more effect to VPT than age in multiple regression, but age group showed to have more effect to VPT than department in general linear model. 5. The variables were transformed to indicator variable to do logistic regression analysis. Department 1, 2, 3 were classified into high exposure (spinning department) and low exposure (other department), age was classified into old (above 30) and young, and work duration was classified into long(above 10 years) and short. The exposure and age were significant variables by logistic regression analysis. Odds ratios of department and VPT on metacarpal bones or malleoli were 2.7-3.2 and those of age and VPT were 2.6 or 2.7. Odds ratio of age and abnormality of VPT on'any point was 3.3(1.59-6.;8), and that of department and VPT was 2.8(1.5-5.5). We concluded that exposure of carbon disulfied was significantly associated with reduction of VPT regardless of age; and that the test of VPT would be useful tool for screening and early detection in neuropathy by carbon disulfide or other neurotoxic chemicals,even though it is simple and cheap.

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.

Prognostic significance of silver-binding nucleolar organizer regions(AgNORs) in prostatic carcinoma: The correlative study with flow cytometric S-phase fraction, proliferation inde and proliferating cell nuclear antigen(PCNA) expression rate / 대한비뇨기과학회지

The nucleolus plays a vital role in control of cell proliferation and protein synthesis. Nucleolar organizer regions (NORs), segment of DNA closely associated with nucleoli, contain coding genes for ribosomal RNA and contribute the regulation of cellular protein synthesis. Detectable by the argyrophilia of associated proteins, silver-binding nucleolar organizer regions (AgNORs) numbers correlate with growth fraction and have been reported the AgNORs counts may have diagnostic and prognostic utility in other human tumors. We investigated further the diagnostic usefulness of the AgNORs technique as a discriminant for malignancy. In addition, we compared the AgNORs counts with flow cytometric analysis of ploidy, S-phase fraction (SPF), proliferation index (PI), and proliferating cell nuclear antigen (PCNA) expression rate. Also, we assessed this technique as a possible prognostic indicator for prostatic carcinoma. There was no linear relationship between the mean number of AgNORs per nucleus versus Gleason histologic grade (r=0.093, p=0.578) and DNA aneuploid group was associated with higher AgNORs counts than diploid group in clinical stage C and D, but the differences were statistically insignificant. The mean number of AgNORs per nucleus had no significant relationship to SPF (r=-0.09, p=0.58) and PI (r=-0.119, p=0.477). Also, there was no significant relationship between mean number of AgNORs and PCNA (r= 0.205, p=0.217). We evaluated the probability, of survival for 29 patients with close follow-up. There was no significant difference of survival between high and low AgNORs number group, even after combined stratification by Gleason grade (Kaplan-Meier analysis with generalized Wil-coxon test). We conclude that this method alone does not offer a reliable histologic discriminanl for malignancy in prostatic tumor, and it is concluded that this technique is of no value in predicting prognosis for prostatic carcinoma.

The study on the urinary N-acetyl-?glucosaminidase concentrations as a early renal injury index in workers exposed to lead, mercury and organic solvents / 대한산업의학회지

No abstract available.

Carpal Tunnel Syndrome among Packing Workers in A Rayon Manufacturing Factory / 예방의학회지

The carpal tunnel syndromes is one of the most common peripheral nerve entrapment syndromes. The typical symptoms are pain, numbness and paresthesia in the median nerve territory of the hand. Recently, it is widely recognized that occupational factor is regarded as the important cause of the carpal tunnel syndrome. Clinical study is performed in the 42 female workers who is repetitively working at packing department in a rayon manufacturing factory from November 1991 till March 1992. The study included a questionnaire, physical examinations, and the neurophysiological test. The summary of the results obtained was as follows: 1. Among 42 packing workers, 9 workers(21.4%) were diagnosed as carpal tunnel syndrome by electromyography. The affected side was bilateral in 4 workers(9.5%), right in 4 workers(9.5%), and left in one worker(2.4%). 2. Among 42 subjects, 28 workers(66.7%) complained the clinical symptoms related to carpal tunnel syndrome, 11 workers(26.2%) showed positive Phalen sign, and 7 workers(16.7%) showed positive Tinel sign. 3. Researchers regard electromyographic finding as the gold standard for diagnosis of carpal tunnel syndrome. The sensitivity and specificity of the clinical symptoms to diagnose the carpal tunnel syndrome were 0.89, 0.39 respectively. If the carpal tunnel syndrome is diagnosed by the combination of the positive findings of the symptoms and the physical examinations, either Tinel of Phalen sign, the sensitivity and specificity were 0.67 and 0.76 respectively. Considering above results, though this small number of worker is not adequate for epidemiologic conclusions, carpal tunnel syndrome seems to be an important occupational disorder among packing workers in a rayon manufacturing factory.

Health status of workers exposed to carbon disulfide at a viscoserayon factory in Korea / 대한산업의학회지

No abstract available.

A Study on the Associatio Between Symptoms and Biological Indicies in Workers Exposed to Lead / 대한산업의학회지

This research was conducted to determine the usefulness of reported symptoms for the diagnosis of lead poisoning for workers exposed to lead. A group of 147 male lead smelting workers were given special physical examinations from June to September of 1989. The examinations included the reporting of ailments(symptoms) by the workers, as well as analyses of their blood lead concentrations and urinary coproporphyrine and delta-aminolevulinic acid concentrations. the associations were analyzed between the bilogical exposure indices and the symptoms described by the workers. The results were as follows: 1. The only symptoms which were described more frequently by the lead workers compared to the control group were paresthesia of the extremities, myalgia, arthralgia, and insomnia. The frequency of other symptoms described were actually lower for the lead-exposed workers. 2. For those workers whose blood lead concentrations were above 60 microgram/dl, only the increase in the frequencies of arthralgia and paresthesia of the xtremities were statistically significant, compared to those workers whose blood lead concentrations were below 60 microgram/dl. Also, arthralgia was the only symptom which increased in frequency in workers whose ruinary coproporphyrine concentrations were above 100 microgram/l; however, this increase was not statistically significant by urinary delta-aminolevulinic acid levels.