• Sleep Medicine and Psychophysiology
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• v.4 no.2
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• pp.164-171
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• 1997

Introduction : Periodic limb movement disorder (PLMD) is shown to common in patients with OSA and may become evident or worsened when treated with nasal continuous positive airway pressure (CPAP). Whether this is due to im proved sleep continuity. adverse nocturnal body positioning, uncovered by CPAP, or due to the CPAP stimulus is still debat-ed. We hypothesized that the increase in PLM activity following CPAP is associated with more supine-sleeping tendencies when being treated with CPAP. In the present work, we compared differences in the PLMD index (PLMI) and sleeping position of patients with sleep disordered breathing before and after CPAP treatment. Method : We studied 16 patients (mean age 46 yr, 9M, 7F) with OSA (11 patients) or UARS (5 patients) who either had PLMD on initial polysomnogram (baseline PSG) or on nasal CPAP trial (CPAP PSG). All periodic leg movements were scored on anterior tibialis EMG during sleep according to standard criteria (net duration; 0.5-5.0 seconds, intervals; 4-90 seconds. 4 consecutive movements). Paired t-tests compared PLMD index (PLMI), PLMD-related arousal index (PLMD-ArI), respiratory disturbance index (RDI), and supine sleeping position spent with baseline PSG and CPAP PSG. Results : Ten patients (63%) on baseline PSG and fifteen patients (94%) on CPAP PSG had documented PLMD ($PLMI{\ge}5$) respectively with significant increase on CPAP PSG(p<0.05). Ten patients showed the emergence (6/10 patients) or substantial worsening (4/10 patients) of PLMD during CPAP trial. Mean CPAP pressure was $7.6{\pm}1.8\;cmH_2O$. PLMI tended to increase from baseline PSG to CPAP PSG, and significantly increase when excluding 2 outlier (baseline PSG, $19.0{\pm}25.8/hr$ vs CPAP PSG, $29.9{\pm}12.5/hr$, p<0.1). PLMD-ArI showed no significant change, but a significant decrease was detected when excluding 2 outlier (p<0.1). There was no significant sleeping positional difference (supine vs non-supine) on baseline PSG, but significantly more supine position (supine vs non-supine, p<0.05) on CPAP PSG. There was no significant difference in PLMI during supine-sleeping and nonsupine-sleeping position on both of baseline PSG and CPAP PSG. There was also no significant difference in PLMI during supine-sleeping position between baseline PSG and CPAP PSG. With nasal CPAP, there was a highly significant reduction in the RDI (baseline PSG, $14.1{\pm}21.3/hr$ vs CPAP PSG, $2.7{\pm}3.9/hr$, p<0.05). Conclusion : This preliminary data confirms previous findings that CPAP is a very effective treatment for OSA, and that PLMD is developed or worsened with treatment by CPAP. This data also indicates that supine-sleeping position is more common when being treated with CPAP. However, there was no clear evidence that supine position is the causal factor of increased PLMD with CPAP. It is, however, suggested that the relative movement limitation induced by CPAP treatment could be a contributory factor of PLMD.

• Sleep Medicine and Psychophysiology
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• v.8 no.2
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• pp.113-120
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• 2001

Objectives: Obstructive sleep apnea syndrome is common and may produce various symptoms and serious complications. A substantial number of research articles on obstructive sleep apnea syndrome have been published in Korea. However, we found such limitations as lack of sufficient sample size and lack of polysomnography-proven cases. Therefore, we aimed at studying clinical features and sleep structure in a sufficient number of Korean patients with obstructive sleep apnea syndrome diagnostically confirmed with polysomnography. Methods: We studied 801 subjects referred to the Division of Sleep Studies, Seoul National University Hospital, who were diagnosed as having obstructive sleep apnea syndrome with polysomnography. Subjects were excluded if they had central sleep apnea syndrome, periodic limb movement disorder, narcolepsy or REM sleep behavior disorder. Foreign patients were also excluded. First of all, we studied the clinical features of the subjects. Secondly, we compared sleep-related parameters of the study subjects with those of age/sex-matched normal values. Thirdly, correlations of respiratory disturbance index (RDI) with each of the sleep-related parameters were calculated. Results: Among the 801 subjects, 668 were male subjects (83.4%) and 133 female subjects (16.4%). Their mean age was 46.6 years (${\pm}13.5$). The mean body mass index (BMI) was 25.8 (${\pm}3.8$) and subjects with BMI was over 28.0 accounted for 22.8% of the total. Fifty subjects (6.2%) were found to take benzodiazepines. Mean RDI and mean nocturnal oxygen saturation of all subjects was 31.2 (${\pm}24.4$) and 94.5% (${\pm}3.6$), respectively. In comparison with normal values, the subjects showed longer sleep latency, lower sleep efficiency, decreased total slow wave sleep % (TSWS %), and decreased total REM sleep % (TREM %)(p<0.01 in all). RDI had a negative correlation with each TSWS % and TREM % (p<0.01, p<0.01). However, RDI did not have significant correlation with either sleep latency or sleep efficiency. Conclusion: In this study, 6.2% of patients diagnosed as having obstructive sleep apnea syndrome were found to take benzodiazepines, although they are generally considered to be of litte benefit or even dangerous because of the respiratory suppressing effect. The proportion of obese subjects was only 22.8% and Korean patients with obstructive sleep apnea syndrome seem to be less obese than those described in foreign journals. This study also suggests that the severity of obstructive sleep apnea syndrome may have a more significant effect on sleep architecture defined as TSWS % and TREM % than on sleep efficiency.

• Korean Journal of Psychosomatic Medicine
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• v.32 no.1
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• pp.1-9
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• 2024

Frailty is a clinical syndrome as an increased vulnerability to stressors, leading to a decrease in physiologic reserves and a decline in the ability to maintain a good homeostasis. This condition leads to an increased risk of hospitalization, disability and mortality. Frailty occurs due to various causes and requires a multidimensional approach. It is also important to detect and manage it early. Frailty is also deeply related to neuropsychiatric problems such as pain and depression. In evaluating frailty, it is desirable to comprehensively consider not only physical areas such as disease, nutrition, movement, and sensory functions, but also psychosocial areas, and representative scales include Fried's physical frailty phenotype and Rockwood's frailty index. Physical activity and appropriate protein intake are important for frailty management, and inappropriate drug use should be reduced and oral care, cognitive function, and falls should also be noted. Frailty and pain can affect each other, and pain can promote frailty. Evidence has been published that hormone and protein abnormalities, immune system activity and inflammatory response, and epigenetic mechanisms work in common in the field of frailty and pain. More extensive and high-quality research should be conducted in the future, and the quality of life will be improved if the results are applied to the suppression and treatment of old age and pain.

• Journal of Life Science
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• v.31 no.3
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• pp.257-265
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• 2021

Heterotrimeric kinesin-2 is a molecular motor protein of the kinesin superfamily (KIF) that moves along a microtubule plus-end directed motor protein. It consists of three different motor subunits (KIF3A, KIF3B, and KIF3C) and a kinesin-associated protein 3 (KAP3) that form a heterotrimeric complex. Heterotrimeric kinesin-2 interacts with many different binding proteins through the cargo-binding domain of the KIF3s. The activity of heterotrimeric kinesin-2 is regulated to ensure that the cargo is directed to the right place at the right time. How this regulation occurs, however, remains in question. To identify the regulatory proteins for heterotrimeric kinesin-2, we performed yeast two-hybrid screening and found a specific interaction with creatine kinase B (CKB), which is the brain isoform of cytosolic creatine kinase enzyme. CKB bound to the cargo-binding domain of KIF3A but did not interact with the KIF3B, KIF5B, or KAP3 in the yeast two-hybrid assay. The carboxyl (C)-terminal region of CKB is essential for the interaction with KIF3A. Another protein kinase, CaMKIIa, interacted with KIF3A, but GSK3a did not interact with KIF3A in the yeast two-hybrid assay. KIF3A interacted with GST-CKB-C but not with GSK-CKB-N or GST alone. When co-expressed in HEK-293T cells, CKB co-localized with KIF3A and co-immunoprecipitated with KIF3A and KIF3B but not KIF5B. These results suggest that the CKB-KIF3A interaction may regulate the cargo transport of heterotrimeric kinesin-2 under energy-compromised conditions in cells.

• Journal of Life Science
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• v.33 no.1
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• pp.1-7
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• 2023

Intracellular cargo transport is mediated by molecular motor proteins, such as kinesin and cytoplasmic dynein. Kinesins make up a large subfamily of molecular motors. Kinesin-1 is a plus-end-directed molecular motor protein that moves various cargoes, such as organelles, protein complexes, and mRNAs, along a microtubule track. It consists of the kinesin superfamily protein (KIF) 5A, 5B, and 5C (also called kinesin heavy chains) and kinesin light chains (KLCs). Kinesin-1 interacts with many different binding proteins through its carboxyl (C)-terminal region of KIF5s and KLCs, but their binding proteins have not yet been fully identified. In this study, a yeast two-hybrid assay was used to identify the proteins that interact with the KIF5A specific C-terminal region. The assay revealed an interaction between KIF5A and glutamate-rich 4 (ERICH4). ERICH4 bound to the KIF5A specific the C-terminal region but did not interact with the C-terminal region of KIF5B or KIF3A (a motor protein of kinesin-2). In addition, KIF5A did not interact with another isoform, ERICH1. Glutathione S-transferase (GST) pull-downs showed that KIF5A interacts with GST-ERICH4 and GST-ERICH4-amino (N)-terminal but not with GST-ERICH4-C or GST alone. When co-expressed in HEK-293T cells, ERICH4 co-localized with KIF5A and co-immunoprecipitated with KIF5A and KLC but not KIF3B. Together, our findings suggest that ERICH4 is capable of binding to KIF5A and that it may serve as an adaptor protein that links kinesin-1 with cargo.

• Journal of Life Science
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• v.32 no.3
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• pp.189-195
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• 2022

Kinesin-2 comprises two subfamilies of the heterotrimeric or homodimeric motors found in mammalian cells. Heterotrimeric kinesin-2 consists of kinesin superfamily proteins (KIFs) 3A and 3B and kinesin-associated protein 3 (KAP3), which is a molecular motor protein that moves along microtubules. It plays diverse roles in cargo transport, including anterograde trafficking in cilia, and interacts with many different cargoes and proteins, but their binding proteins have not yet been fully identified. In this study, the yeast two-hybrid assay was used to identify the proteins that interact with the cargo-binding domain (CBD) of KIF3A, and an interaction between KIF3A and brain expressed X-linked 2 (Bex2) was found. Bex2 bound to the CBD-containing C-terminal tail region of KIF3A but did not interact with the same region of KIF3B or KIF5A (a motor protein of kinesin-1). KIF3A interacted with another isoform, Bex1, but did not interact with Bex3. In addition, glutathione S-transferase (GST) pull-downs showed that KIF3A specifically interacts with GST-Bex1 and GST-Bex2 but not with GST alone. When co-expressed in HEK-293T cells, Bex2 co-localized with KIF3A and co-immunoprecipitated with KIF3A and KIF3B but not KIF5B. In combination, these results suggest that Bex2 is capable of binding to heterotrimeric kinesin-2 and may serve as an adaptor protein that links heterotrimeric kinesin-2 with cargo.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.1
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• pp.9-19
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• 2016

Many patients with dizziness present with a symptom pattern that does not reveal the cause by neurotologic diagnostic approaches. In such cases, the physician frequently diagnoses psychogenic dizziness. Psychogenic dizziness is not characterized by true vertigo, and occurs in combination with other psychiatric symptom cluster. One out of two to four patients with dizziness are psychogenic dizziness. But there are few concern about this including clinical practice and study in Korea. I wrote this paper to increase concerning and attending to this for psychiatrists in Korea. I reviewed etiology including biological and psychological relations between dizziness and psychiatric disorder(especially anxiety), diagnostic approaches of, characteristics of dizziness of various psychiatric disorders related to, and the treatment of psychogenic dizziness. I also briefly reviewed the central and peripheral dizziness for psychiatrists. I suggest psychiatrists and clinicians in the psychosomatic field in Korea to acknowledge, concern, and attend to psychogenic dizziness. In turn, it will be helpful to well treat the patients with psychogenic dizziness.

• Korean Journal of Psychosomatic Medicine
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• v.32 no.1
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• pp.24-33
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• 2024

Objectives : The purpose of this study was to investigate individual- and community-level factors on suicidal ideation and suicide attempt among Korean adults. Methods : This study was conducted on 225,965 adults collected through data from the 2021 Community Health Survey and the Korean Statistical Information Service (KOSIS). The general characteristics, suicidal behavior (e.g., suicidal ideation, and suicide attempts), and community-level characteristics of the study subjects were analyzed using frequency (%) and mean (standard deviation). The effects on individual- and community-level factors on suicidal ideation and suicide attempts was analyzed using multilevel logistic regression models. Results : The community-level factor associated with suicidal ideation was unmet health care (Odds Ratio [OR]=1.053, 95% CI=1.035-1.071), and the community-level factor associated with suicide attempt was the aging rate (OR=1.015, 95% CI=1.001-1.030). Regarding health-related variables, the individual-level factors associated with suicidal ideation were stress status (OR=9.388, 95% CI=8.629-10.213), depressive experience in the past year (OR=6.737, 95% CI=6.454-7.032), and the predominantly individual-level factors associated with suicide attempt were also stress status (OR=5.213, 95% CI=3.699-7.347), and depressive experience in the last one year (OR=13.433, 95% CI: 11.247-16.044). Conclusions : We confirmed individual-level and community-level factors influencing suicidal ideation and suicide attempt. Through these findings, we need to establish suicide prevention policies, considering managing individual-level factors such as stress and depression as well as community-level factors such as unmet health care.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2002.05a
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• pp.211-215
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• 2002

본 실험은 종합적 인지과정을 추론할 수 있는 결합 문제(binding problem)를 언어적인지 과정을 통해 알아 본 실험으로, 총 10 명(남:61여:4, 평균나이:24.40 $\pm$ 1.35)의 정상군을 대상으로, 4개의 음소로 이루어진 단음절 명사를 목표 자극(target stimulus)으로 하고, 4개 음소의 임의적인 조합으로서 글자를 이루지 못하는 비목표 자극(non-target stimulus)을, 각각 200 회와 800 회씩 시각적으로 0.5초씩 무작위로 제시하여 128 채널 고밀도 사건관련전위(ERP)를 측정하였다. 이번 실험 결과의 주요 특징은 글자가 아닌 비목표 자극보다 글자인 목표 자극에서 두드러지게 나타난 두정엽 부근의 P500 과 N900 이라고 할 수 있다. 자극 제시 비율의 차이에서 오는 oddball 효과로 인한 기존 P300 의 인지적 의미를 이번 결과의 P500 이 함축한다고 볼 수 있으며, 단음절 단어를 인지할 때, 글자임을 인식하는 순간은 의미적인지 과정이 진행되었다기보다 그 글자의 형태만으로 낯익은 글자인지를 분간하는 것으로 보인다 따라서, 이 경우 기존 언어 실험에 자주 등장하던 의미론적 peak 인 N400 은 보이지 않고, 곧바로 형태적이고, 통사적(syntactic)인 인지 처리 과정인 P500이 나타났다고 해석할 수 있다. 하지만, 이번 실험에서는 N400 대신에 N900 이 나타났다. 이 결과는 이번 ERP 실험과 병행된 프로토콜 분석을 통해, 피험자가 자극 제시 후, 약 900ms 정도에, 이미 제시되고 사라진 글자 자극을 다시 한번 떠올리는 인지 과정이 일어난다는 점과 관련 지어 해석하면, 기존에 의미적(semantic) 인지 과정으로만 해석했던 negative-peak 를 생각(thinking)과 같은 내재적인지 과정(internal cognitive process)으로 확장하여 일반화하는 추론도 생각해 볼 수 있다. 요컨대, 언어인지를 통한 이번 실험을 통해, 뇌파에서 검출되는 negative-peak 은 internal cognitive process로 추측되고, positive-peak 는 external cognitive process 라고 생각된다. 덧붙여, 유의해서 볼 점은 각 peak-topology 에서 Cz 의 진폭이 Fz 보다 크게 나온 점과, 일반적으로 언어 기능을 담당한다는 좌측 측두엽(T7)이 우측(T8)보다 통계적으로 더 유의미한 차이를 보였다는 점등이다.

• Journal of Life Science
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• v.30 no.1
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• pp.10-17
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• 2020

Kinesin-1 is microtubule-dependent plus-end direct molecular motor protein essential for intracellular transport. It is a member of the kinesin superfamily proteins (KIFs) which transport cargo, including organelles, vesicles, neurotransmitter receptors, cell-signaling molecules, and protein complexes through interaction between its light chain subunit and the cargo. Kinesin light chain 1 (KLC1) is a non-motor subunit that associates with the kinesin heavy chain (KHC). Although KLC1 interacts with many different adaptor proteins and scaffolding proteins, its binding proteins have not yet been fully identified. We used the yeast two-hybrid assay to identify proteins that interact with the tetratricopeptide repeat (TPR) domain of KLC1, and found an interaction between KLC1 and EH domain-binding protein 1 like 1 (EHBP1L1). EHBP1L1 bound to the region containing all six TPR repeats of KLC1 and did not interact with KIF5B (a motor protein of kinesin 1) or KIF3A (a motor protein of kinesin 2) in the yeast two-hybrid assay. The carboxyl-terminus of the coiled-coil domain of EHBP1L1 is essential for interaction with KLC1. However, another EHBP1L1 isoform, EHBP1, did not interact with KLC1 in the yeast two-hybrid assay. KLC1 interacted with GST-EHBP1L1 and its coiled-coil domain but not with GST only. When co-expressed in HEK-293T cells, EHBP1L1 co-localized with KLC1 and co-immunoprecipitated with KLC1 and KIF5B but not KIF3A. These results suggest that kinesin 1 motor protein may transport EHBP1L1-associated cargo in cells.