• Sleep Medicine and Psychophysiology
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• v.15 no.2
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• pp.77-81
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• 2008

Introduction: REM sleep which shows characteristic muscle atonia and increased resistance of upper respiratory track is known to be vulnerable to sleep apnea. Previous studies reported that REM sleep-dependent (or related) obstructive sleep apnea syndrome (REM-dependent OSA) could be one of sleep disordered breathing. The present study aimed to investigate clinical findings and polysomnographic variables of REM-dependent OSA. Methods: Fifty-six patients diagnosed with mild to moderate obstructive sleep apnea by overnight polysomnography (5$53.7{\pm}16.7$ years, 42 males). REM-dependent OSA was defined as AHI-REM/AHI-NREM ratio>2. We compared clinical and polysomnographic findings between REM-dependent OSA and No REM-dependent OSA patients. Results: Among 56 patients, 37.5% (n=21, average age of $52.3{\pm}19.7$ years, 14 males) met the REM-dependent OSA criteria. There were no significant differences in age, sex and body mass index between two groups. After controlling for age, sex, body mass index and periodic leg movements index, REM-dependent OSA patients showed significantly lower AHI, lower number of oxygen desaturation events and higher stage 2 sleep proportion compared to No REM-dependent OSA patients (p=0.010, p=0.006, p=0.031, respectively). After controlling for age, sex, body mass index and periodic legs movements index, AHI-REM was positively correlated with the number of oxygen desaturation events in REM-dependent OSA group (p=0.002). Conclusion: Current results suggested that 37.5% of patients with mild to moderate severity of obstructive sleep apnea could be classified into REM-dependent OSA. REM-dependent OSA was more common in mild severity of OSA, equally prevalent in both sexes and accompanied with sleep architecture changes, i.e. increased proportion of stage 2. In addition, apneic events during REM sleep in REM-dependent OSA were related to oxygen desaturation.

• Clinical and Experimental Pediatrics
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• v.52 no.6
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• pp.689-695
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• 2009

Purpose : To examine the effect of bosentan, a dual endothelin receptor (ER) antagonist, on the development of monocrotaline (MCT)-induced pulmonary hypertension in rats by especially focusing on the pulmonary vascular morphology changes. Methods : Sprague-Dawley rats were treated as follows: controls received a subcutaneous saline injection, MCT-treated rats received a subcutaneous MCT injection, and bosentan-treated rats received a MCT injection followed by treatment with bosentan (20 mg/kg/day). To assess the effects of ER blockade on the time course, the animals were exsanguinated, and their hearts and lungs were dissected after 7, 14, or 28 days. Results : The mean body weights of the MCT- and bosentan-treated rats were significantly lower than that of the control rats on days 7, 14, and 28. Bosentan administration significantly inhibited the progression of right ventricular hypertrophy on day 28 (right ventricle/[left ventricle＋septum]: $0.71{\pm}0.10$ in MCT-treated rats vs. $0.49{\pm}0.09$ in bosentan-treated rats; P<0.05). Quantitative analysis of peripheral pulmonary arteries revealed that the increase in medial wall thickness after MCT injection was significantly attenuated in the bosentan-treated rats on day 28 ($49.96{\pm}10.06%$ in MCT-treated rats vs. $47.09{\pm}10.48%$ in bosentan-treated rats; P<0.05). In addition, the increase in the number of intra-acinar muscular arteries after MCT injection was reduced by bosentan on days 14 and 28. Conclusion : Bosentan administration in intermediate doses exerts inhibitory effects on lung vascular hypertrophy and right ventricular hypertrophy during the development of MCT-induced pulmonary hypertension in rats.

• Sleep Medicine and Psychophysiology
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• v.10 no.1
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• pp.52-60
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• 2003

Objectives: Stage 1 sleep provides important information regarding interpretation of nocturnal polysomnography, particularly sleep onset. It is a short transition period from wakeful consciousness to sleep. The lack of prominent sleep events characterizing stage 1 sleep is a major obstacle in automatic sleep stage scoring. In this study, utilization of simultaneous EEG and EOG processing and analyses to detect stage 1 sleep automatically were attempted. Methods: Relative powers of the alpha waves and the theta waves were calculated from spectral estimation. A relative power of alpha waves less than 50% or relative power of theta waves more than 23% was regarded as stage 1 sleep. SEM(slow eye movement) was defined as the duration of both-eye movement ranging from 1.5 to 4 seconds, and was also regarded as stage 1 sleep. If one of these three criteria was met, the epoch was regarded as stage 1 sleep. Results were compared to the manual rating results done by two polysomnography experts. Results: A total of 169 epochs were analyzed. The agreement rate for stage 1 sleep between automatic detection and manual scoring was 79.3% and Cohen’s Kappa was 0.586 (p<0.01). A significant portion (32%) of automatically detected stage 1 sleep included SEM. Conclusion: Generally, digitally-scored sleep staging shows accuracy up to 70%. Considering potential difficulty in stage 1 sleep scoring, accuracy of 79.3% in this study seems to be strong enough. Simultaneous analysis of EOG differentiates this study from previous ones which mainly depended on EEG analysis. The issue of close relationship between SEM and stage 1 sleep raised by Kinnari remains a valid one in this study.

• Childhood Kidney Diseases
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• v.3 no.1
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• pp.20-26
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• 1999

Purpose : Several modulatory factors for renal peripheral benzodiazepine receptor (PBR) has been reported, but their physiological significance remains elusive. Tissue-specific, stress-induced down-regulation of renal PBR coupled with the pharmacological stimulation of these effects by angiotensin II suggested that physiological significance of renal PBR may be related to the pathophysiology of stress-induced hypertension. The boderline hypertensive rat (BHR) has been used extensively to study the interaction of environmental factors, such as stress and blood pressure. The BHR is the first-generation progeny of a cross between the spontaneously hypertensive rat and the control Wistar-Kyoto rat. The pathogenesis of stress induced hypertension in this model is not demonstrated well. Methods In this study, BHR (male, 150-200 g) and Sprague-Dawley (SD, male, 150-200 g) rats were treated by repeated immobilization to induce anxiety. We used plus-maze performance to observe the level of anxiety by measuring percent open crosses and percent time in open. Results : Percent open crosses and percent time in open in BHR were lower than in SD rats (P<0.05). Receptor densities of renal PBR in BHRs were significantly lower than those of SDs (P<0.05). We also observed that the renal PBR was upregulated in the repeatedly stressed (immobilization, 2 hours daily, for 2 weeks) rats, both in the BHR and SD. However, the density of renal PBR in the stressed BHR was still lower than that of stressed SD. Renal PBR has been suggested to be an important organs which Is responsible for the production of cholesterol-derived products during stress. Conrlusion : From these results, it can be summarized that the lowed density of renal PBR may be involved in the pathogeneis of stress-induced hypertension.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1550-1557
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• 2015

This study was conducted to evaluate the improvement effects of bitter taste of doraji (Platycodon grandiflorum) with different freezing temperature conditions ($-5^{\circ}C$, $-10^{\circ}C$, $-20^{\circ}C$, and $-70^{\circ}C$). After freezing for 4 h, frozen doraji was thawed and dehydrated. Doraji frozen at $-20^{\circ}C$ showed higher contents of crude fat, crude protein, crude ash, crude fiber, and nitrogen free extract. Moisture, crude saponin, and total polyphenol contents of doraji frozen at $-5^{\circ}C$ were higher than in other samples. Weight loss of doraji was significantly different as freezing temperature decreased and the process repeated. Doraji frozen at $-5^{\circ}C$ showed higher contents of saponin and phenol than the control. Hardness of doraji increased as freezing temperature decreased. According to the preference test, Doraji frozen at $-5^{\circ}C$ showed higher preference and less bitter taste intensity than other samples. These results mean that doraji frozen at $-5^{\circ}C$ with less bitter taste could be utilized widely as a food material.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.6
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• pp.701-707
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• 2008

Antidiabetic effect of Korean red ginseng (RG) processed by puffing in streptozotocin (STZ)-induced diabetic (DM) rats was investigated. Five week-old SD rats were divided into four groups; normal control (NC) group, DM group, red ginseng (RG) group and puffed red ginseng (PG) group. The RG and PG groups were orally provided with RG or PG dissolved in water (500 mg/kg) respectively for seven weeks after single injection of STZ (50 mg/kg, i.v.) followed by identification of DM. NC group received saline vehicle instead of STZ. At the end of feeding of RG or PG, the changes of fasting blood glucose, serum insulin and amylase level and serum lipid profiles were evaluated. Also, oral glucose tolerance test (OGTT), comet assay and histopathological examination were performed. At 7th week, the fasting blood glucose levels of the RG and PG groups were reduced compared to the DM group by 11.54% and 20.22%, respectively. The result of OGTT did not show significant differences among DM and two red ginseng groups. While serum insulin and TG levels were predominantly improved in PG group (p<0.05), serum amylase level was increased in RG group. Alkaline comet assay for checking the oxidative damage of DNA showed that TL (tail length, ${\mu}m$) and TM (tail moment) in the blood lymphocyte of PG group significantly decreased in contrast with DM group. Histopathological results of pancreas showed that destruction of exocrine as well as endocrine might be cured by the administration of RG and PG. These results suggest that PG could exert more protection against STZ-induced toxicity than RG group.

• Tuberculosis and Respiratory Diseases
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• v.50 no.2
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• pp.196-204
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• 2001

Background : Bronchial asthma is characterized by a reversible airway obstruction, airway hyperresponsiveness, and eosinophilic airway inflammation. The bronchodilator response(BDR) after short acting beta agonist inhalation and PC20 with methacholine inhalation are frequently used for diagnosing bronchial asthma. However, the relationship between the presence of a bronchodilator response and the degree of airway hyperresponsiveness is uncertain. Therefore, the availability of a eosinophil cationic protein (ECP) and a correlation ECP with a bronchodilator response and airway hyperresponsiveness was investigated. Method : A total 71 patients with a moderate to severe degree of bronchial asthma were enrolled and divided into two groups. 31 patients with a positive bronchodilator response and 38 patients with a negative bronchodilator response were evaluated. In both groups, the serum ECP, peripheral blood eosinophil counts, and total IgE level were measured and the methacholine bronchial provocation test was examined. Results : There were no differences observed in age, sex, atopy, and baseline spirometry in both groups. The peripheral eosinophil counts showed no difference in both groups, but the ECP level in group 1 (bronchodilator responder group) was higher than in group 2(non-bronchodilator responder group) ($22.4{\pm}20.7$ vs $14.2{\pm}10.4$, mean$\pm$SD). The PC20 in group 1 was significantly lower than in group 2 ($1.14{\pm}1.68$ vs $66{\pm}2.98$). There was a significant positive correlation between the BDR and ECP, and a negative correlation between the bronchial hyperresponsiveness and ECP. Conclusion : The bronchodilator response significantly correlated with the bronchial hyperresponsiveness and serum ECP in the moderate to severe asthma patients. Hence, the positive bronchodilator response is probably related with active bronchial inflammation and may be used as a valuable index in treatment, course and prognosis of bronchial asthma.

• Sleep Medicine and Psychophysiology
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• v.5 no.1
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• pp.103-110
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• 1998

Objectives : High co-morbidity of periodic limb movements during sleep(PLMS) and obstructive sleep apnea syndrome(OSAS) is well known and their incidences tend to increase in the elderly. Previous studies have inconsistently rep0l1ed increase or no change of periodic limb movement index(PLMI) by nasal continuous positive airway pressure(CPAP) in OSAS without analyzing possible variables affecting PLMI. We attempted to examine PLMI change evoked during CPAP titration and also factors affecting it in OSAS. Methods : Twenty-nine OSAS patients(M:F=26:3, mean age: $51.6{\pm}10.6\;yrs$) without other sleep disorders except for PLMS were selected, based on the nocturnal (baseline) polysomnograhy. Another night of noctumal polysomnography was performed for CPAP pressure titration. We compared between those two nights PLMI, mean and lowest $SaO_2$, and sleep variables. We also calculated PLMI differences between baseline and CPAP nights, named as delta PLMI (value of CPAP night PLMI minus value of baseline night PLMI). Correlations were calculated between delta PLMI and factors such as age, body mass index, applied CPAP pressure, baseline night values of respiratory disturbance index, mean and lowest $SaO_2$, and sleep parameter differences between baseline and CPAP nights. Results : Decrease of RDI(p<.01) and increase in mean and lowest $SaO_2$ (p<.05, p<.01) were observed during CPAP night. No sleep parameters showed significant change except for the decrease of total stage 1 sleep%(p<.01) during CPAP night. Ten out of 29 patients showed PLMI increase, while the other 19 patients showed either no change(n=14) or even PLMI decrease(n=5) during CPAP night. The 10 patients showing PLMI increase during CPAP night showed a significant positive correlation between delta PLMI and baseline night RDI(p<.05), which meant that PLMI increase was found to be more prominent in higher RDI patients than in lower RDI ones. There were no significant correlations between delta PLMI and other factors in the other 19 patients. Conclusions : We suggest that during the baseline night PLMS would have been underscored and/or masked due to the overlapping of PLMS and apneas/hypopneas or the arousals induced by apneas/hypopneas. Despite its still unknown mechanism, the CPAP application may unmask PLMS and increase PLMI in a subgroup of OSAS patients. It needs to be evaluated further whether the chronic CPAP use sustains the above finding.

• Sleep Medicine and Psychophysiology
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• v.6 no.2
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• pp.110-115
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• 1999

Objectives: To investigate the effect of mandibular repasitioning device on airway sige and airway collapsibility in patients with obstructive sleep apnea syndrome(OSAS). Methods: Cine CT with polysomnographic monitoring was performed during sleep in nine(OSAS) patients before and after manibular repositioning device(MRD) application. Axial CT images were obtained in five upper airway levels(retropalatal-high, retroalatal-low, retroglossal, epiglottis, and hypopharynx levels). In each airway level, one axial CT image was obtained during sleep apnea period and 10 serial axial CT images were scanned every 1 second during normal sleep breathing. After wearing MRD, all CT images were obtained by the same method. The cross-sectional areas of airway were measured by automatic tracing method. The changes of minimum airway size and maximum airway size after MRD were evaluated. The airway collapsibility was calculaed before and after MRD. Results: During sleep apnea, the airway of retropalatal-low level was the most frequently narrowest site. During normal sleep breahing the minimum airway size was increased significantly after MRD at retropalatal-low level(p=0.011). The mean airway collapsibility was the highest at retropalatal-low level. MRD decreased the airway collapsibility significantly at retropalatal-low level(p=0.021) and epiglottis level(p=0.038). Conclusions: The enlargement of the minimum airway size and decreased airway collapsibility may be the therapeutic mechanism of MRD in 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.