서정택 교수

Differentiation of neuronal cells has been shown to accelerate stress-induced cell death, but the underlying mechanisms are not completely understood. Here, we find that early and sustained increase in cytosolic ([Ca2+]c) and mitochondrial Ca2+ levels ([Ca2+]m) is essential for the increased sensitivity to staurosporineinduced cell death following neuronal differentiation in PC12 cells. Consistently, pretreatment of differentiated PC12 cells with the intracellular Ca2+-chelator EGTA-AM diminishe

Periodontitis is an inflammatory disease caused by bacteria. In periodontitis, reactive oxygen species (ROS) are released from inflammatory cells in response to bacteria. Interleukin (IL)-8 is one of pro-inflammatory cytokines. To investigate the role of ROS in pathogenesis of periodontitis, we estimated the effect of H₂O₂, one of ROS, on the expression of IL-8 in human periodontal ligament (PDL) cells. PDL cells were treated with H₂O₂. IL-8 expression was determined by reverse transcription-pol

Melanocortins have been implicated in human sebum secretion for a long time. However, the signalling pathways of α-melanocyte-stimulating hormone (α-MSH) in human sebocytes expressing melanocortin receptors (MC-Rs) are still poorly understood. Because calcium ions play a central role in MC-R signalling, we investigated whether α-MSH affects calcium signalling in the immortalized human sebocyte cell line SZ95. In addition, we investigated the impact of α-MSH on MC-1R expression and lipid synthesi

In a previous study, we reported that alpha-hydroxy acids (AHA), such as glycolic acid and lactic acid, did not induce any significant changes in transepidermal water loss for normal murine skin. The ultrastructural observations, however, showed that the extent of lamellar body exocytosis significantly increased. Because AHA can theoretically decrease the calcium ion concentration by chelation, topical AHA may induce the loss of epidermal calcium gradient by lowering the calcium ion concentratio

Synaptotagmin is a Ca2+ sensing protein, which triggers a fusion of synaptic vesicles in neuronal transmission. Little is known regarding the expression of Ca2+-dependent synaptotagmin isoforms and their contribution to the release of secretory vesicles in mouse and rat parotid acinar cells. We investigated a type of Ca2+-dependent synaptotagmin and Ca2+ signaling in both rat and mouse parotid acinar cells using RT-PCR, microfluorometry, and amylase assay. Mouse parotid acinar cells exhibited mu

Korea became an aged society as of 2018, and will have plunged into a super-aged society by 2025. For the dental treatment of elderly patients, their general conditions are to be considered to make appropriate treatment plans and strategies, based on advanced knowledge of geriatric dentistry and clinical experience. In this study, the social demand for geriatric dental specialists for the treatment of the elderly of Korea is investigated by looking at their general health conditions, ADL (Activi

This study analyzed the change in the rater reliability based on the student's practice evaluation process conducted at Yonsei University College of Dentistry. Through this, we suggest the significance of the rater calibration training in the student's practical evaluation of dental college. Nine professors from the department of Conservative Dentistry, Yonsei University College of Dentistry, analyzed the results of class II restoration cases twice in 2017 and once in 2018. Intra Class Correlati

Inhibition of Rho-associated coiled coil-containing kinase (ROCK) has been reported to promote differentiation of neuronal cells. Here, we examined the effect of Y-27632, a ROCK inhibitor, on the outgrowth of neurites in PC12 cells. Y-27632 caused a rapid induction of neurite outgrowth in PC12 cells in a time-dependent manner. The neurite outgrowth, triggered by Y-27632, was accompanied by Rac1 activation, and was attenuated by Rac1 inhibitor NSC23766, in a concentration-dependent manner. Y-2763

In the present study, we investigated the effect ofstaurosporine on the formation of cellular processes in humangingival fibroblasts and rat astrocytes. Staurosporine caused arapid induction of process formation in human gingivalfibroblasts and rat astrocytes in a concentration dependentmanner. The process formation of human gingival fibroblastsand rat astrocytes was prevented by the pretreatment withN-acetylcysteine, suggesting that staurosporine-induced ROSproduction was responsible for the pr

Xylitol is a sugar alcohol with a variety of functions including bactericidal and anticariogenic effects. However,the cellular mechanisms underlying the role of xylitol in bone metabolism are not yet clarified. In our present study, we exploited the physiological role of xylitol on osteoclast differentiation in a co-culture system of osteoblastic and RAW 264.7 cells. Xylitol treatment of these co-cultures reduced the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated ce

H2O2, a member of reactive oxygen species (ROS), is known to be involved in the mediation of physiological functions in a variety of cell types. However, little has been known about the physiological role of H2O2 in exocrine cells. Therefore, in the present study, the effect of H2O2 on cholecystokinin (CCK)-evoked Ca2+ mobilization and amy-lase release was investigated in rat pancreatic acinar cells. Stimulation of the acinar cells with sulfated octapeptide form of CCK (CCK-8S) induced biphasic

Objective: Previous studies suggested the potential influence of YouTube videos regarding dentistry on the mass population. However, there was not any clear investigation for Korean population. We aimed to systemically analyze the type of the dentistry-related videos uploaded on YouTube Korea and the accounts used for uploading, and to assess their effect on the view count of the content. Methods: Classification, type of the accounts, and view count of the videos listed by the keyword ‘dentistry

Osteoporosis is a common disease characterized by bone mass reduction, leading to an increased risk of bone fracture, and it is caused by an imbalance of osteoblastic bone formation and osteoclastic bone resorption. Current osteoporosis drugs aim to reduce the risk of bone fracture, either by increasing osteoblastic bone formation or decreasing osteoclastic bone resorption. However, osteoblasts and osteoclasts are closely coupled, such that any reagent altering the differentiation or activity of