• Journal of Ginseng Research
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• v.12 no.1
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• pp.1-10
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• 1988

Panax ginseng seedlings were grown at various temperature regimes from 15 to $30^{\circ}C$ for 19 days under dark and the linear relationship between various regrowth efficiencies and thermal stress indices, cumulative superoptimum temperatures corrected with factors. Gross growth efficiency(shoot weight l root weight loss) was 37.5 % at the optimum temperature $15^{\circ}C$/$15^{\circ}C$, and 12.3% at the highest temperature, $30^{\circ}C$/$30^{\circ}C$ while net growth efficiency (shoot weight + Sm)l(root loss-Rm), which corrected by maintenance respiration for shoot(Sm) and root(Rm) was 39.6% and 16.7 at optimum and highest temperature respectively. All growth efficiencies showed negative correlations (p = 0.001) with all thermal stress indices and negative(p = 0.001) with shoot growth(St). When growth temperature difference in a day was nil or above $15^{\circ}C$ growth efficiency decreased greatly. Thermal stress indices showed negative correlation with root dry matter loss(RDL) but positive with Rm. St showed positive correlation with RDL. Thermal stress appeared to inhibit substrate supply for shoot growth resulting in the extremely low growth efficiency comparing with other crops that seems to be main rate limiting factor of slow growth, Thus it is necessary that growth efficiency and thermal stress must be elucidated in terms of metabolic pathway.

• Sleep Medicine and Psychophysiology
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• v.16 no.2
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• pp.65-73
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• 2009

Objectives: The purpose of this study was to assess the clinical and polysomnographic characteristics of Korean patients with obstructive sleep apnea syndrome (OSAS), especially in relation to differences due to age and gender. Methods: All subjects were consecutive patients who were proven to have OSAS with nocturnal polysomnography. They were interviewed with a structured interview format including sociodemographic information, past medical history, medication, and sleep-related history. Simultaneously, they were also given Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) to answer in order to check subjective sleep quality and subjective sleepiness. Results: Mean age of the 308 subjects was $49.5{\pm}$13.3 years, with 77.6% of the subjects being males and 22.4% of the subjects being females. The aging effects on the sleep architecture in Korean OSAS corresponded with normal aging, but with the effect of OSAS itself superimposed, the extent of aging effects was more marked than that of normal aging. The severity of Korean patients of OSAS was not correlated with age. When divided into age subgroups, significant correlation was found between RDI and BMI in patients of each subgroup of those in the 4th to 7th decades. The oldest subgroup (>70 years) described their subjective sleep quality as poorer than any other age subgroups, despite of less subjective drowsiness. The severity of OSAS and the change of sleep architecture of male subjects turned out to be severer than those of female ones. The female/male ratio of the subjects tended to increase with aging. Conclusions: The aging effect on the sleep architecture in Korean OSAS seems to be a mixture of the changes by normal aging and sleep disorder per se. The severity of OSAS was not correlated with age, but highly correlated with BMI. The severity of OSAS and the change of sleep architecture of male patients were severer than those of female ones.

• Tuberculosis and Respiratory Diseases
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• v.56 no.4
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• pp.364-373
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• 2004

Background : Obstructive sleep apnea is a contributory factor of hypertension, arrhythmia, ischemic heart disease and other cardiovascular diseases. However, the pathophysiology underlying this relationship is unclear. Recent reports have shown that the soluble intercellular adhesion molecule-1(sICAM-1) and vascular endothelial growth factor(VEGF) are involved in the initiation and progression of atherosclerosis, and some reports state that increased levels of these cytokines are found in patients with obstructive sleep apnea. In this study, the levels of sICAM-1 and VEGF were measured in patients with obstructive sleep apnea in order to determine if obstructive sleep apnea is involved in the pathophysiology of cardiovascular diseases. Methods : Thirty-seven patients were chosen amongst a population who visited the Sleep Disorders Clinic of St. Paul's Hospital in Seoul, Korea for a diagnosis of obstructive sleep apnea and who had subsequently undergone an overnight polysomnography at the clinic. The sera from these patients were retrieved after an overnight polysomnography session and the samples were kept at $-70^{\circ}C$. The cytokine levels were determined with ELISA and the relationships between the serum levels of sICAM-1 and VEGF along with polysomnography parameters were analyzed. Results : No statistically significant correlation was observed between the sICAM-1 levels and the apnea-hypopnea index(r=0.27, P>0.05). Positive correlations were found between the apnea-hypopnea index and serum VEGF levels (r=0.50, P<0.01), the apnea index and the serum sICAM-1 levels (r=0.31, P<0.01), and the apnea index and the serum VEGF levels (r=0.45, P<0.01). Conclusions : Obstructive apnea or hypopnea leads to an increase in the sICAM-1 and VEGF levels. Such an increase in the cytokine levels most likely leads to the higher incidence of cardiovascular diseases observed in patients with obstructive sleep apnea.

• Sleep Medicine and Psychophysiology
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• v.9 no.1
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• pp.24-33
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• 2002

Objectives: Nasal continuous positive airway pressure (CPAP) corrected elevated blood pressure (BP) in some studies of obstructive sleep apnea syndrome (OSAS) but not in others. Such inconsistent results in previous studies might be due to differences in factors influencing the effects of CPAP on BP. The factors referred to include BP monitoring techniques, the characteristics of subjects, and method of CPAP application. Therefore, we evaluated the effects of one night CPAP application on BP and heart rate (HR) reactivity using non-invasive beat-to-beat BP measurement in normotensive and hypertensive subjects with OSAS. Methods: Finger arterial BP and oxygen saturation monitoring with nocturnal polysomnography were performed on 10 OSAS patients (mean age $52.2{\pm}12.4\;years$; 9 males, 1 female; respiratory disturbance index (RDI)>5) for one baseline night and another CPAP night. Beat-to-beat measurement of BP and HR was done with finger arterial BP monitor ($Finapres^{(R)}$) and mean arterial oxygen saturation ($SaO_2$) was also measured at 2-second intervals for both nights. We compared the mean values of cardiovascular and respiratory variables between baseline and CPAP nights using Wilcoxon signed ranks test. Delta ($\Delta$) BP, defined as the subtracted value of CPAP night BP from baseline night BP, was correlated with age, body mass index (BMI), baseline night values of BP, BP variability, HR, HR variability, mean $SaO_2$ and respiratory disturbance index (RDI), and CPAP night values of TWT% (total wake time%) and CPAP pressure, using Spearman's correlation. Results: 1) Although increase of mean $SaO_2$ (p<.01) and decrease of RDI (p<.01) were observed on the CPAP night, there were no significant differences in other variables between two nights. 2) However, delta BP tended to increase or decease depending on BP values of the baseline night and age. Delta systolic BP and baseline systolic BP showed a significant positive correlation (p<.01), but delta diastolic BP and baseline diastolic BP did not show a significant correlation except for a positive correlation in wake stage (p<.01). Delta diastolic BP and age showed a significant negative correlation (p<.05) during all stages except for REM stage, but delta systolic BP and age did not. 3) Delta systolic and diastolic BPs did not significantly correlate with other factors, such as BMI, baseline night values of BP variability, HR, HR variability, mean SaO2 and RDI, and CPAP night values of TWT% and CPAP pressure, except for a positive correlation of delta diastolic pressure and TWT% of CPAP night (p<.01). Conclusions: We observed that systolic BP and diastolic BP tended to decrease, increase or remain still in accordance with the systolic BP level of baseline night and aging. We suggest that BP reactivity by CPAP be dealt with as a complex phenomenon rather than a simple undifferentiated BP decrease.

• Tuberculosis and Respiratory Diseases
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• v.60 no.1
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• pp.76-82
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• 2006

Background : The objective of this study was to understand sleep-related problems, and to determine whether the sleep questionnaires is a clinically useful method in patients who need polysomnography. Methods : Subjects were patients who performed polysomnography and who asked to answer a sleep questionnaires at the Sleep Disorders Clinic of St. Paul's Hospital, Catholic University of Korea. Baseline characteristics, past medical illness, behaviors during sleep-wake cycle, snoring, sleep-disordered breathing and symptoms of daytime sleepiness were analyzed to compare with data of polysomnography. Results : The study population included 1081 patients(849 men, 232 female), and their mean age was $44.2{\pm}12.8years$. Among these patients, 38.9% had an apnea-hypopnea index(AHI)<5, 27.9% had $5{\leq}AHI<20$, 13.2% had $20{\leq}AHI<40$, and 20.0% had $40{\leq}AHI$. The main problems for visiting our clinic were snoring(91.7%), sleep apnea(74.5%), excessive daytime sleepiness(8.0%), insomnia(4.3%), bruxism(1.1%) and attention deficit(0.5%). The mean value of frequency of interruptions of sleep was 1.6 and the most common reason was urination(46.3%). Epworth Sleepiness Scale(ESS) had a weak correlation with AHI(r=0.209, p<0.01). When we performed analysis of sleep questionnaires, there were significant differences in the mean values of AHI according to the severity of symptoms including snoring, daytime sleepiness, taking a nap and arousal state after wake(p<0.05). Conclusion : On the basis of statistical analysis of sleep questionnaires, the severity of subjective symptoms such as ESS, snoring, daytime sleepiness and arousal state after wake correlated with the AHI significantly. Therefore the sleep questionnaires can be useful instruments for prediction of the severity of sleep disorder, especially sleep-disordered breathing.

• Sleep Medicine and Psychophysiology
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• v.24 no.2
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• pp.86-96
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• 2017

Objectives: This study aimed to analyze causality among sleep apnea, depression and cognitive function in patients with obstructive sleep apnea. Methods: We reviewed the medical records of 105 patients with sleep apnea and snoring who underwent overnight polysomnography (PSG). We analyzed various biological data, sleep variables (sleep duration and percentage) and respiratory variables [arousal index (AI), periodic leg movement index (PLM index), snoring Index (SI), mean SpO2, minimum SpO2, apnea-hypopnea index (AHI), and respiratory disturbance index (RDI)]. We also analyzed various data by sleep, cognition, and mood related scales: Pittsburgh sleep quality index (PSQI), Epworth sleepiness scale (ESS), snoring index by scale (SIS), Montreal Cognitive Assessment-Korean (Moca-K), Mini-mental State Examination-Korean (MMSE-K), clinical dementia rating (CDR), and Beck Depression Inventory (BDI). We analyzed causation among sleep, and respiratory, mood, and cognition related scales in obstructive sleep apnea patients. We analyzed the mediating effects of depression on sleep apnea patient cognition. Results: As Duration N1 increased and Total sleep time (TST) decreased, MOCA-K showed negative causality (p < 0.01). As BDI and supine RDI increased, causality was negatively related to MOCA-K (p < 0.01). As PSQI (p < 0.001) and SIS (p < 0.01) increased and as MMSE-K (p < 0.01) decreased, causality was positively related to BDI. BDI was found to mediate the effect of age on MOCA-K in patients with obstructive sleep apnea. Conclusion: Duration N1, total sleep time, BDI, and supine RDI were associated with cognitive function in obstructive sleep apnea patients. Depression measured by BDI partially mediated cognitive decline in obstructive sleep apnea patients.

• Korean Journal of Psychosomatic Medicine
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• v.10 no.1
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• pp.37-47
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• 2002

Objective : Previous studies have suggested an association between sleep-related breathing disorder (SRBD) and several psychological problems, and there were increasing recognition of the link. The purpose of this study is to evaluate the characteristic profiles of MMPI and SCL-90-R in patients with SRBD. Methods : This study consisted of 80 SRBD patients(73 men, 7 women) referred from Sleep Disorder Clinic of Dong-A University Hospital, Busan, Korea. Basic informations including demographic findings and physical examination were collected. Subjects completed the Epworth Sleepiness Scale(ESS), Minnesota Multiphasic Personality Inventory(MMPI), and Symptom Check List-90-Revision (SCL-90-R) prior to standard overnight polysomnography that was performed at hospital sleep laboratory. SRBD was divided into two groups of primary snoring(PS) and obstructive sleep apnea(OSA) according to polysomnographic findings. Results : SRBD showed significant elevation rate of Hs, D, and Hy scales of MMPI and SOM scale of SCL-90-R, which exceeded the rate expected in normal individuals(>5%, 2SD). On comparison of clinical scales of SCL-90-R, OSA group had significantly greater mean score than that of PS group in terms of O-C, DEP, PAR, GSI(p<0.05), SOM and PST(p<0.01). OSA group also showed significantly higher elevation rate in Hs scale of MMPI and SOM scale of SCL-90-R than that of PS. Among OSA group, three scales of MMPI(D, Pt, Si) and three scales of SCL-90-R(ANX, PAR, PSDI) had significant correlation with some PSG variables including total sleep time and sleep efficiency. Among PS group, two scales of MMPI(Hy and Pt), elevation rate of MMPI scales and three scales of SCL-90-R(I-S, PAR, PSDI) had significant correlation with some PSG variables including sleep efficiency, sleep latency and REM sleep percent. Conclusion : The above results suggest that SRBD show neurotic profiles in MMPI and SCL-90-R. This study also clearly indicates that PS group are suffered from clinically meaningful psychiatric symptoms, which are quantitatively lessened but qualitatively similar as compared to that of OSA group.

• Tuberculosis and Respiratory Diseases
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• v.44 no.2
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• pp.309-320
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• 1997

Background : There are many suggested methods for the indirect determination of anaerobic threshold(AT) using the changes of ventilatory parameters in response to ventilatory load accompanying the increase of blood lactic acid level during exercise and the threshold derived from them is called ventilatory threshold(VT). They include ventilatory equivalent method(VEM), End-tidal $PO_2$ method($PETO_2$). V-slope method(VSM), and respiratory quotient method(RQ). But in the patients with chronic airway obstruction(CAO), the AT determined by ventilatory methods may not reflect true AT because the patients with CAO show inadequate ventilatory response to the increase of blood lactic acid level during excercise. Methods : For the investigation of detection rate and reliability of above four VT determination methods in the patients with CAO, we performed the symptom-limited and maximal incremental exercise test in 17 patients with CAO and 12 normal controls. The incremental workload was 10 W /min in CAO group and 25 W/min in control group. The reliability of VT in each group was investigated by the calculation of Spearman correlation coefficient. Results : The detection rates of VT were 100% by RQ, 91.7% by both VEM and $POETO_2$, and 83.3% by VSM in normal control group, while 94.1% by RQ, 64.7% by VEM and $PETO_2$, and 83.3% by VSM in CAO group. Good correlations were noted among VEM, $POETO_2$, and VSM except RQ in normal control group. But there was no significant correlation except between VEM and $PETO_2$ in CAO group. Conclusions : RQ is very sensitive but crude and VEM is near similar to $PETO_2$. The clinical usefulness of VT determined by ventilatory method might be limited in patients with severe CAO.

• Sleep Medicine and Psychophysiology
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• v.13 no.1
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• pp.27-32
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• 2006

Objectives: Nasal continuous positive airway pressure (nCPAP) is the treatment of choice and has been shown to reduce the frequency of nocturnal respiratory events, improve sleep architecture, and decrease daytime sleepiness in patients with obstructive sleep apnea syndrome (OSAS). However, little is known about the compliance of nCPAP treatment in Korea. Our objective was to look into the nCPAP compliance and examine the factors influencing it. Methods: We reviewed the records of one hundred and twenty consecutive patients with OSAS referred for nocturnal polysomnography with nCPAP pressure titration during the period of January 1995 through April 1999 to the Seoul National University Hospital. We performed a telephone interview and obtained data from eighty-three patients. Results: In sixty patients who had accepted nCPAP treatment, twenty-six patients (43.3%) were still using nCPAP device, while thirty-four patients (56.7%) stopped using it. Fifteen patients (25%) were using nCPAP device everyday. In thirty-four patients who discontinued nCPAP use, twenty-five patients (73.5%) did within the first three months, and thirty-one (91.2%) within the first year. Significant predictor of long-term nCPAP use was the presence of subjective daytime sleepiness before nCPAP application. Conclusions: Long-term compliance with nCPAP treatment appears to be associated with the presence of subjective daytime sleepiness before nCPAP application. Long-term compliance with nCPAP may be mostly predicted from the usage pattern within the first three months of use.

• Sleep Medicine and Psychophysiology
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• v.1 no.2
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• pp.172-181
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• 1994

Obstructive sleep apnea syndrome(OSAS) is most frequently diagnosed in the sleep laboratories and its severity is objectively estimated. In terms of treatment, the most prevalent method is the continuous positive airway pressure(CPAP) application as of now. However, in Korea, CPAP is still not sufficiently known and it is attributable to the fact that sleep study facilities have not been popularized. In this article, the authors present their own experience with CPAP in nine subjects with OSAS. In this study, CPAP was found to decrease stage 1 sleep and to increase stage 2 sleep, with increasing mean oxygen saturation and decreasing lowest oxygen saturation during nocturnal sleep. Also, it tended to increase sleep continuity and generally to improve sleep architecture. Rebound slow wave and/or REM sleep stages during CPAP were also noted in 8 out of 9 cases. The authors suggest that CPAP should be considered as the primary mode of treatment for patients with obstructive sleep apnea syndrome and related educational programs for physicians should be developed and provided by sleep specialists.