OBJECTIVES: Obstructive sleep apnea syndrome (OSAS) not only causes respiratory disturbances during sleep but also decreases the quality of nocturnal sleep through sleep fragmentation and sleep structure change. We aimed at comparing the changes in sleep fragmentation and structure between baseline (diagnostic) nocturnal polysomnography (NPSG) and nCPAP (nasal continuous positive airway pressure) titration trial. METHODS: One hundred and three patients with a baseline night of respiratory disturbance index (RDI) of 5 or greater and reduced RDI score during nCPAP titration night were retrospectively selected for the study. Sleep fragementation and sleep structure between baseline NPSG and the NPSG during nCPAP titration were compared. Sleep fragmentation index (SFI) was defined as the total number of awakenings and shifts to stage 1 sleep divided by the total sleep time in hour. SFI and other polysomnographic parameters were statistically compared between the two nights. RESULTS: SFI during baseline NPSG and nCPAP titration nights were 29.0+/-13.8 and 15.2+/-8.8, respectively, indicating a significant SFI decrease during nCPAP titration (t=9.7, p<0.01). SFI showed significant negative correlations with sleep efficiency (r=-0.60, p<0.01) and total sleep time (r=-0.45, p<0.01) and a positive correlation with RDI (r=0.28, p<0.01). CONCLUSION: Use of nCPAP, even during the titration, significantly decreases sleep fragmentation and improves sleep structure in OSAS patients. We suggest that SFI may be utilized as a measure of assessing OSAS severity and nCPAP efficacy.
Humans ; Polysomnography ; Retrospective Studies ; Sleep Apnea, Obstructive ; Sleep Deprivation

The reciprocal interaction between sleep and pain has been reported by numerous studies. Patients with acute or chronic pain often complain of difficulty falling asleep, frequent awakenings, shorter sleep duration, unrefreshing sleep, and poor sleep quality in general. According to the majority of the experimental human studies, sleep deprivation may produce hyperalgesic changes. The selective disruption of slow wave sleep has shown this effect more consistently, while results after selective REM sleep deprivation remain unclear. Patients with chronic pain have a marked alteration of sleep structure and continuity, such as frequent sleep-stage shifts, increased nocturnal awakenings, decreased slow wave sleep (SWS), decreased rapid eye movement (REM) sleep, and alpha-delta sleep. Many analgesic medications can alter sleep architecture in a manner similar to the effects of acute and chronic pain, suppressing SWS and REM sleep.
Chronic Pain ; Humans ; Sleep Deprivation ; Sleep, REM

INTRODUCTION: Although it is well known that medical students are not getting an adequate amount of sleep, there have been only few studies on the sleep patterns of medical students in Korea. Therefore, the present study aimed to investigate the life style and sleep patterns of Korean medical students and the impact they have on the students' academic performance. METHODS: A questionnaire package was administered to the 3rd year medical students at the Seoul National University to examine their sleep patterns on weekdays and weekends. It consisted of questions asking about their lifestyles as well as Pittsburgh sleep quality index (PSQI) and GPA (Grade Point Average) that are considered relevant to their sleep patterns. A total of 110 students (85 males and 25 females, mean age 24.4+/-20.6) responded to the survey and the result was analyzed using the independent t-test, the chi-square test, the paired t-test, Pearson's rank correlation and ANOVA. P-values of less than 0.05 were considered statistically significant in all analyses. RESULTS: The weekend bedtime was significantly delayed (01:24 on weekday; 03:12 on weekend; t=-5.23, p<0.01), the weekend rise time was delayed (07:36 on weekday; 10:30 on weekend; t=-24.48, p<0.01) and the total sleep time was increased on weekends (5:57 on weekday; 8:17 on weekend; t=15.94, p<0.01). They wished to sleep for 7 hours 6 minutes which was different from their actual weekday total sleep time (t=-11.41, p<0.01). The poor sleeper group had lower GPAs than the good sleeper group (t=2.05, p<0.05). The GPA of medical students were negatively correlated with age (r=-0.23, p<0.05), daily amount of smoking (r=-0.78, p<0.01), total amount of smoking (r=-0.75, p<0.01), weekday sleep latency (r=-0.23, p<0.05), weekend sleep latency (r=-0.23, p<0.05) and PSQI score (r=-0.30, p<0.01). CONCLUSION: Medical students were experiencing a lack of sleep during weekdays as they have a later bedtime and earlier rise time, and consequently had more hours of sleep on weekends. Overall, the responded students were experiencing poor sleep quality, and the GPAs of the poor sleeper group were lower than those of the good sleeper group.
Female ; Humans ; Korea ; Life Style ; Male ; Surveys and Questionnaires ; Smoke ; Smoking ; Students, Medical

OBJECTIVES: Chronic pain is one of the most common experiences of humans and a typical psychophysiological disorder. The aim of this study was to measure the psychophysiological responses in chronic pain patients using a biofeedback system, and to compare them with the results from normal healthy subjects. METHODS: Forty two patients with chronic pain (17 males and 25 females, average age 44.67+/-11.10 years) and 42 normal healthy controls (17 males and 25 females, average age 45.17+/-10.46 years) participated in this study. Electromyography (EMG), skin conductance (SC), and skin temperature (ST) were recorded using biofeedback system during the 3 phases (baseline, stress, and recovery) of stress reactivity test, and average values of them were calculated. Difference of values between two groups in each corresponding phase was analyzed with independent t-test, and change of values across phases of stress reactivity test was analyzed with paired t-test (all two-tailed, p<0.05). RESULTS: Compared to normal controls, chronic pain patients had higher value of EMG (baseline : 8.10+/-5.97 micronV vs 4.72+/-1.52 micronV, t=-3.56, p<0.01 ; stress : 11.25+/-6.89 micronV vs 8.49+/-4.78 micronV, t=-2.13, p<0.05 ; recovery : 7.12+/-3.77 micronV vs 4.78+/-1.59 micronV, t= -3.70, p<0.01) and SC (baseline : 1.06+/-1.0 micronS vs 0.42+/-0.29 micronS, t=-4.0. p<0.01 ; stress : 1.87+/-2.05 micronS vs 1.03+/-0.86 micronS, t=-2.47, p<0.05 ; recovery : 1.74+/-1.77 micronS vs 0.64+/-0.59 micronS, t=-3.8, p<0.01) in all the 3 phases. But, skin temperature comparison did not reveal significant differences in all the 3 phases between two groups. CONCLUSION: Psychophysiological responses of chronic pain patients in stress reactivity test were different from those of normal healthy controls. These results suggest that sympathetic nervous system is more activated in chronic pain patients.
Biofeedback, Psychology ; Chronic Pain ; Electromyography ; Female ; Humans ; Male ; Psychophysiologic Disorders ; Psychophysiology ; Skin ; Skin Temperature ; Sympathetic Nervous System

Lovastatin, a competitive inhibitor of the rate limiting enzyme in cholesterol biosynthesis was administered to 34 patients with primary hypertlipidemia, 20 mg once daily with the evening meal. Patients experienced mean total and LDL cholesterol reductions of 30.9% and 34.0% respectively. HDL cholesterol level was significantly increased by 15.4% and plasma triglyceride level was decreased by 11.2%. maximal hypocholesterolemic effects were evident at 8 weeks, after which the effects were stable. Adverse effects were noted in 2 patients who had mild gastrointestinal symptoms, that subsided after discontinuing the drug. We concluded that lovastatin is a well tolerated and effective agent for the treatment of primary hyperlipidemia.
Cholesterol ; Cholesterol, HDL ; Cholesterol, LDL ; Humans ; Hyperlipidemias* ; Lovastatin ; Meals ; Plasma* ; Triglycerides

Diabetes mellitus is known to be associated with a specific cardiomyopathy. This is evident from the clinical-pathological work and the epidemiologic data. An investigation was made in this study to determine whether diabetic cardiomyopathy in rats is associated with an alteration of biochemical characteristics of cardiac contractile proteins. Rats were made diabetic with intravenous injection of streptozotocin and hearts removed 8 weeks later for the isolation of myofibrils. The basal ATPase activity of myofibrils from diabetic hearts was significantly lower than that of the controls, suggesting the presence of some subtle structural and conformational changes in diabetic myofibrils. The activating effect of Mg ions on the myofibrillar actomyosin system of rat heart muscle was also demonstrated. Sodium dodecylsulfate gel electrophoresis showed the presence of myosin heavy chain, light chain 1 and 2, actin and troponin but failed to reveal differences in the patterns of these contractile proteins of light subunits between diabetics and controls. The deficiency in utilization of energy rich phosphates by the myofibrillar protein may be one of of the main mechanisms of cardiodepression observed in diabetic hearts. The cardiac myofibrillar ATPase activity may be one of useful measurements in evaluating pathophysiological states of cardiac contractile proteins.
Actins ; Actomyosin ; Adenosine Triphosphatases* ; Animals ; Cardiomyopathies ; Contractile Proteins ; Diabetes Mellitus ; Diabetic Cardiomyopathies ; Electrophoresis ; Heart ; Injections, Intravenous ; Ions ; Myocardium ; Myofibrils ; Myosin Heavy Chains ; Phosphates ; Rats* ; Sodium ; Streptozocin ; Troponin

The present study was aimed at investigating the effect of cyclosporine A (CsA) on the renal renin-angiotensin systems. In rats chronically treated with CsA, the intrarenal expression of various genes of the renin-angiotensin system was assessed by Northern blot analysis. Along with the increases in plasma and renal renin activities, chronic CsA-treatment differentially affected the renal expression of renin-angiotensin system. The treatment with CsA for one week did not significantly alter the expression of either type 1 angiotensin II receptor (AT1A) or angiotensinogen gene, but increased the renin mRNA level. The three-week-treatment caused increases in the expression not only of renin but also of AT1A and angiotensinogen genes. Supplementation with L-arginine kept the expression of renin mRNA normal in the one-week-treated, but failed to prevent the alterations of the gene expression in the three-week-treated. Feedback control among components of the renin-angiotensin system also influences angiotesinogen. In the liver, the expression of angiotensinogen mRNA was decreased by the CsA-treatment for either one- or three-weeks. In conclusion, chronic CsA-treatment is associated with a differential expression of various genes for the renin-angiotensin system. L-Arginine may be effective in maintaining the normality of renin-angiotensin system only during early period after beginning the use of CsA.
Angiotensinogen ; Animals ; Arginine ; Blotting, Northern ; Cyclosporine* ; Gene Expression ; Liver ; Plasma ; Rats ; Receptors, Angiotensin ; Renin ; Renin-Angiotensin System* ; RNA, Messenger

Epidemiological and statistical observations were made of fire hazards that occurred during the past 18 years, 1948 to 1965. Injury and mortality rates for all ages were computed chronologically. For the years of 1955, 1961 and 1965, all fire accidents were epidemiologically analysed to draw characteristic pattern in relation to the seasonal and 24 hour distribution, causes and sites of accidents etc.. Fire hazards observed herein are the categorys E 916 of the International Classification of Causes of Death, 1955, and includes all accidents caused by fire and explosion of combustible materials. The following conclusion was made: 1. The average umber of annual deaths due to fire was 183 and the number of the injured due to the same cause was 335. The mortality rate per 100,000 population was 0.8 and the ratio of injures per death was 1.8. 2. The casualty rate including both the dead and injured was 5.0 per 100,000 in Seoul, the highest among the provinces and followed by 3.4 in Cheju-Do, 2.1 in Kangwon-Do, 1.7 in Kyunggi-Do accordingly. The other provinces had a range of 0.6 to 1.2. 3. The monthly distribution of fire accidents showed that the winter months, December through February, had more frequent accidents, while the summer season, June through August had less. The 24 hour distribution of accidents showed more cases from 12:00 to 18:00 and less from 4:00 to 10:00 hours. 4. The per cent distribution of causes of accidents showed; 90.0% for careless, 10.0% for arson. The cause of carelessness was further breakdown into; 15.0% for kitchen fire places, 13.8% for fire playing, 9.4% for electrical heating and wires, 8.3% for fuels, 6.3% for matches, 5.2% for ash dumps and the remaining for others. 5. The accidents as classified by place revealed that 56.8% of the total occurred at the common dwelling houses, 11.3 at various industrial workshops, 9.3% at the street shops and the remaining at the miscellaneous places.
Cause of Death ; Classification ; Education ; Explosions ; Fires* ; Firesetting Behavior ; Gangwon-do ; Gyeonggi-do ; Heating ; Hot Temperature ; Jeju-do ; Korea* ; Mortality ; Seasons ; Seoul

Because of the frequent misdiagnosis of the carpal injury, the orthopedic surgeon must know the mechanism of injury and exact radiological interpretation. We had encountered 114 cases of carpal injury, in which carpal fracture, carpal dislocation and instability were analysed by radiological examination. The following results were obtained: 1. In 75 carpal bone fractures, the most common fracture was scaphoid fracture (64 cases), the next com- mon one was triangular fracture (4 cases). 2. Among the 64 scaphoid fractures, the waist portion was the most frequent site (45 cases) and the least was tubercle fracture (2 cases). 3. Of the carpal bone fractures, the fresh fracture was 48 cases (64%) and old one was 27 cases (36%), these showed sclerosis, cystic change, and degenerative change in radiological examination. 4. In 14 carpal dislocations, perilunar dislocation was 2.5 times move common than lunate dislocation, and the trans-scaphoid perilunar dislocation was the most common dislocation. 5. Carpal instability was 25 cases. These were dorsiflexion instability, navicular rotary subluxation, and pal- mar-flexion instability. The most common instability was dorsiflexion instability.
Carpal Bones ; Classification ; Diagnostic Errors ; Dislocations ; Incidence ; Orthopedics ; Sclerosis ; Wrist

OBJECTIVES: OSAS (obstructive sleep apnea syndrome) is a common disorder and its consequences are often serious. It is important to detect the disorder early in the course for proper treatment. This study is to grasp the snoring clinic visitors' knowledge level of OSAS. METHODS: One hundred and seventy-nine visitors at the of snoring clinic of Seoul National University Hospital were surveyed by questionnaire about reasons of visit and knowledge of treatment methods of snoring and OSAS, diagnostic method, OSAS-related symptoms, and complications. RESULTS: Most of the respondents (89.4%) "have already heard about OSAS" and the major sources of information was the mass media (58.1%) such as television and radio. More than half (60.3%) were aware that snoring is closely related to OSAS. More than half (59.8%) recognized that a nocturnal polysomnograpy was necessary for proper diagnosis. Two thirds (67%) of the respondents noted surgery as a treatment for snoring. More than half (55.9%) answered that they would follow the doctor's advice on the treatment choice. Only 12.3% of respondents "have heard about nCPAP". No one chose nCPAP (nasal continuous positive airway pressure) as a treatment for either snoring or OSAS. About one third (34.6%) of the respondents were aware that OSAS is related to hypertension. Only 12.8% noted that OSAS is related to diabetes mellitus. CONCLUSION: Visitors at the snoring clinic were found to have substantially limited knowledge of health risks and proper treatments of OSAS. We suggest that it is crucially important to educate patients and offer easy-to-understand information on snoring and OSAS. We predict that provision of educaiton and information to patients and general public will faciliate the diagnosis and treatment of snoring and OSAS and reduce the related disorders such as hypertension, stroke, and diabetes mellitus.
Diabetes Mellitus ; Hand Strength ; Humans ; Hypertension ; Mass Media ; Surveys and Questionnaires ; Sleep Apnea Syndromes ; Sleep Apnea, Obstructive ; Snoring ; Stroke ; Television