An Experimental Study on the Changes of Rabbit EEG by Reoxygenation after the Exposure to Carbon Monoxide

BACKGROUND: Hyperbaric oxygen (HBO) therapy is applied for the treatments of various diseases inducing hypoxic states. However, reoxygenation of previously hypoxic tissue results in significant tissue damages through the mechanisms of oxygen toxicity. The authors investigated the characteristics of the EEG changes by hyperbaric oxygenation after the exposure to carbon monoxide, and the protective effects of allopurinol, an inhibitor of xanthine oxidase (XO), to the brain. METHODS: Sixty eight male rabbits of New Zealand white weighing 1,350-2,000 gm, were used. The rabbits were divided in 4 groups and measured EEG for 21 hours of experiments. RESULT: The delta waves were significantly increased and alpha waves significantly decreased, during CO exposure, HBO exposure only, and HBO exposure after CO exposure (P< 0.05 in all groups). The wave changes were most remarkable in CO-HBO group, and in this case the changes continued to the last period of the ambient air exposure stage. The brain injury did not decrease as appeared in EEG changes in rabbits treated with allopurinol. This result suggests that many other mechanisms might be involved in CO-HBO condition. The paroxysmal electrical discharges were mostly appeared during or after HBO exposure stages. CONCLUSION: The changes of EEG characteristic in hyperbaric oxygenation are the increase of delta wave and electrical paroxysmal discharges. There is no protective effect of allopurinol to the brain, which suggests that many other mechanisms other than XO might be involved.

An Outbreak of Vivax Malaria in Republic of Korea in 1999 / 감염

BACKGROUND: Annual occurrence of vivax malaria in Republic of Korea (ROK) has exceeded 1,000 cases since 1997. Military system is thought to be a important source of the current outbreak. We collected the information on malaria cases of ROK army, veterans and civilians which occurred in 1999, and analyzed the characteristics of the current outbreak. METHODS: Informations on malaria cases of ROK army, including name, age, sex, rank, force, day of onset, region, etc., were collected through the Office of Surgeon General at Headquarters of ROK army and then analyzed. Informations about malaria cases of veterans and civilians, including age, sex, day of onset, region, etc., were collected through the National Institute of Health and then analyzed. RESULTS:Among a total of 3,628 cases in 1999, 1,085 (29.91%) occurred in the military, 996 (27.45%) occurred in veterans, and 1,547 (42.64%) occurred in civilians. Monthly occurrence reached its peak level at July and had maintained to August. Yeoncheon, Cheolwon and Paju were the highest prevalence region. CONCLUSION: Case occurrence in ROK decreased in 1999 and it was contributed by chemoprophylaxis which has been done since 1997 in the military. It is thought that more attention must be given to protect the further spread of malaria infection.

Sister-Chromatid Exchanges in Lymphocytes of Medical Students Exposed to Formaldehyde / 대한산업의학회지

Sister-chromatic exchanges measured in the peripheral lymphocytes of 15 non-smoking medical students after exposure to formaldehyde during a 24-week anatomy class showed a small but significant (p=0.0468) increase when compared with samples obtained from the same individuals immediately before exposure. Mean frequencies of sister-chromatic exchange of cultured peripheral lymphocytes were 5.40+/-0.24 from the samples before exposure and 5.87+/-0.22 from the same samples after exposure. Breathing-zone air samples collected by formaldehyde monitoring kit with digital colorimeter (SKC) showed a mean concentration of 0.72+/-0.02 ppm formaldehyde.

Symptom Prevalence of Work-Related Musculoskeletal Disorders and Related Factors among Bank Workers by Visual Dispaly Terminal Use / 대한산업의학회지

The purpose of this study is to investigate the relationship between the self-reported musculoskeletal symptoms and related factors among VDT operators in bank. The subjects were 950 women workers. The characteristics of subjects were 26.6 years of average age, 5.7 years of average VDT use duration and 6.5 hours of daily VDT use time. The results were as follows. The prevalence of self-reported musculoskeletal symptoms more than severe in Likert scale were 51.4%, 43.9% at the shoulder, 38.3%, 31.8% at the lower back, 38.0%, 31.3% at the neck, 31.2%, 25.2% at the upper back, 21.7%, 16.5% at the wrist and 13.6%, 8.8% at the fingers (while on duty, after home-coming). General characteristic variables affecting the musculoskeletal symptoms were married, number of child and daily house-working time. Work-related factors affecting the musculoskeletal symptoms were VDT working career, daily working time, daily VDF use time, VDF use time without rest, daily work-load and regular rest. As the result of the multiple logistic regression analysis, daily working time, daily VDT use time and VDT working career were significant variables accounting for the musculoskeletal symptoms.

Changes of Visual Acuity and Ophthalmic Symptoms in Female Workers examining Silver Plating Products / 예방의학회지

To evaluate the effects of reflected glare on eyes, authors assessed the periodic health examination(1991-1996) and self-administered questionnaire data of a semiconductor producing company. The 13 lead frame(LF) department workers have been exposed to high reflected glare in the process for examining the silver plating products. We compared the data of connector(14) and clerical(12) workers as the non-exposed ones. Among LF department workers, 100% felt their visual acuity worsened(connector:81.8%, clerical:85.7%), and 70% had worn the glasses or contact lenses(connector :14.3 %, clerical :40%) since working at the company. Major ophthalmic symptoms of the LF workers are asthenopia, tearing, decreased visual acuity, congestion and glare. Decrease of visual acuity by Hahn's line change of the LF workers is significantly high during a 5-year follow-up(p<0.05 by simple regression) compared with connector, clerical workers.

Effect of Benzoic Acid Containing Foods on the Urinary Hippuric Acid Concentration in Workers Exposed to Toluene / 대한산업의학회지

This Study was performed to investigate the effect of foods containing benzoic acid on the urinary hippuric acid concentration in the toluene exposed workers. The urinary hippuric acid concentration were measured at 0, 30, 60, 90, 120, and 150 minute after intake of soft drink and bread containing benzoic .acid: in volunteers,: who did not have been exposed toluene occupationally. After that urinary hippuric: acids also were measured at the end of shift in toluene exposed workers. And also the concentration of toluene in air were analysed! by gas chromatography. So the relationships between urinary hippuric acid concentration and age, work duration, concentration of toluene in air and intake of benzoic acid containing food were observed. The results were as follows: 1. The urinary hippuric acid concentration reached the highest level at 30 minute after intake of soft drink with bread at a level of 1.41g/g creatinine and soft drink; alone at a level of 1.04g/g creatinine which contained benzoic acid among unexposed toluene, and then gradually decreased. 2. In toluene exposed group no significant effect of general; characteristics siich; as gender, age, work duration, drinking and smoking on urinary: hippuric acid concentration was showed in toluene exposed group. 3. The mean value of urinary hippuric acid concentration of group taking benzoic acid containing foods was significantly higher than that of group not taking. 4. Multiple regression analysis showed that toluene concentration in .air and benzoic acid containing foods were together significantly influence on urinary ; hippuric acid concentration. And the function between variables is Y = 0.014Tpluene +0.489Benzoic acid +0.745 and the contribution rates were 31%. In conclusion, it was suggested that the information on intake of benzoic acid containing foods should be considered in measurement of urinary hippuric acid for the more accurate toluene exposure evaluation.

Epidemiological Study on the Mumps Epidemic: In one Primary School in Hwasung-Kun, Kyonggi-Do / 한국역학회지

In the last years, according to the increasing incidence of measles and other viral diseases, it have been needed to study on not only the fundamental epidemiological characteristics of mumps and measles but also judgement on the effectiveness of vaccine that meet our domestic situation. The author carried out questionnaire to obtain epidemiological characteristics and vaccine efficacy of mumps on epidemics of mumps in one primary school in Hwasung-kun, Kyonggi Do from Feb. to July, 1994. The results are summarized as follows: 1. Total students was 556, but 446(78.4%) responded to the questionnaire. Among that 446,130(29. 1%) have suffered from mumps. From 9 to 10 year old students had the high attack rates, especially 10 year olds has the highest(39. 7%). 2. From Feb. 2, 1994, first case was on, to July 6, 1994, the epidemic was continues, and attack rate was higest in May(50. 5%). 3. Among the 130 mumps patients, 5 have suffered from complication(3.8%) : encephalitis 3(2 in male, 1 in female). 4. Vaccination rate was 91%, and as ages were lowered, the rates were higher. 5. Attack rate was higher in group who had time interval after vaccination less than 5 years than total attack rate, and was higher in group who had been vaccined after 5 year old. 6. Attack rate in vaccinated group was 27.3%. 7. Vaccine efficacies, be judged by three methods of analysis according to case definition and vaccination status, were 37.4 39. 2%. 8. Factors that have significantly affected the mumps epidemic were vaccination status and vaccination age.

A Study on the Relationship between Subjective symptoms and Psychological Symptoms on some VDT workers / 예방의학회지

The study subjects in this study are 295 workers who work on one electronics industry, and they were composed of 93 VDT and 202 non-VDT workers. This study was carried out to obtain the prevalence of subjective symptoms and to compare psychological symptom scores from SCL-90-R between VDT and non-VDT work groups. And to verify the relationship between VDT work related symptoms and psychological symptoms, the author compared scL-90-R T scores between symptom complaining and non-complaining groups. The results are summarized as follows: 1. Throughout the prevalence study of VDT work related symptoms according to VDT work state, the author could select the final 10 symptoms by sex; 'eye fatigue', 'foggy vision', 'neck discomfort or pain'. 'shoulder discomfort and pain', 'light headedness', 'dizziness', 'aene`, 'itching sensation on face', 'difficulty in concentration', 'memory disturbance' in males, and 'blurred vision`, 'foggy vision', 'neck discomfort or pain', 'shoulder discomfort and pain`, 'abdominal distention','indigestion', 'acne', 'pricking sensation on face', 'difficulty in concentration', 'memory disturbance` in females. 2. Throughout comparison of psychological symptom scores from SCL-90-R between VDT and non-VDT workers' except `interpersonal sensitivity` in female, Mean T score were higher in VDT workers, but not significantly different between the two groups. These results indicate that the relation between VDT work status and psychological symptoms are not strongly correlated. 3. Because of the nonspecific characteristics of VDT work related symptoms, from the 40 subjective symptoms, the author selected the final 10 symptoms by sex, especially correlated to VDT, and divided the study subjects into symptom complaining and non-complaining groups. The mean SCL-90-R T score between the two groups were compared. Except for the opthalmologic symptoms in females, the scores were significantly different between the two groups in all symptoms. And this indicates that the VDT work related symptoms strongly correlated with the present individual psychological conditions. 4. Due to understand that which of the 9 psychological symptom dimensions are strongly correlated with the subjective symptoms, the author excuted multiple logistic regression analysis, and the result were as follows; 'depression' and 'somatization', in male, and 'obsessive-compulsive' and 'somatization' in female.