• Proceeding of EDISON Challenge
• /
• 2017.03a
• /
• pp.698-702
• /
• 2017

배아줄기세포 유래 심근세포는 심근경색 등으로 심장이 제 기능을 다 하지 못할 때 치료적 목적으로 주사하여 환자의 심기능을 정상화 시키는 데에 쓰인다. 배아줄기세포 유래 심근세포는 페이스메이커 활동을 보이면서 막전압 고정상태에서도 주기적인 일과성 내향전류를 보이는 특징을 갖고 있다. 본 연구는 기존에 발표된 배아줄기세포 유래 심근세포의 시뮬레이션 모델을 이용하여 어떻게 하여 페이스메이커 활동이 나타나는지 그 기전을 밝히고자 하였다. 세포내 모든 이온을 고정하였을 때 모델 세포는 여전히 페이스메이커 활동을 보였다. 근장그물내 칼슘 이온을 고정하였을 때도 모델 세포는 페이스메이커 활동을 보였다. 그러나 Na-Ca 교환 전류를 차단하였을 때는 모델 세포의 페이스메이커 활동이 사라졌는데, 여기서 L-type $Ca^{2+}$ 전류의 칼슘 의존성 비활성화 기전을 제거하자 페이스메이커 활동이 지속되었다. 또한 Na-Ca 교환전류와 L-type $Ca^{2+}$ 전류만으로는 페이스메이커 활동이 보이지 않았으나 L-type $Ca^{2+}$ 전류의 크기를 3배로 증가시키자 페이스메이커 활동이 다시 나타남을 확인하였다. 따라서, 배아줄기세포 유래 심근세포의 페이스메이커 활동은 Na-Ca 교환전류와 L-type $Ca^{2+}$ 전류의 역할이 매우 중요하며, Na-Ca 교환전류는 L-type $Ca^{2+}$ 전류가 비활성화되지 않도록 칼슘 이온의 농도를 조절하는 데에 큰 역할을 하는 것으로 결론을 내렸다.

• Journal of Chest Surgery
• /
• v.29 no.5
• /
• pp.477-486
• /
• 1996

Endogenous analgesic systems are known to be activated by peripheral noxious stimulation as well as arterial carbon dioxide elevation. In the present study, neuronal Activities in the rostral ventrolateral med- ulla were identified and classified in according to their rhythmic activities, and their responses to noxious peripheral nerve stimulations before and after elevating the arterial carbon dioxide partial pressure were investigated Using extracellular recording technic, a total of 53 spontaneously active neurons were recorded from the rostral ventrolateral medulla in u-chloralose anesthetized cats. These were classified as cardiovascular (28), respiratory (16), both cardiovascular and respiratory (2) and noncardiovascular - nonrespiratory (7). - Among the 28 cardiovascular neurons eleven showed increased activities during arterial hypercapnia, thirteen showed decreased responses, and four showed no change. Nine respiratory neurons showed increased responses to arterial hypercapnia, six showed decreased responses and one showed no change. neither of the cardiovascular and respiratory neurons showed significant change in its activity during ar- terial hypercapnia, however, four of the noncardiovascular - nonrespiratory neurons exhibited decreased their activities in response to arterial hypercapnia while two exhibited increased activities. Arterial hypercapnia increased the responses of cardiovascular neurons to peripheral nerve stimulation with C-inteniity, while not changing the responses to Ak_stimulation significantly . From the above results it was conclllded that during arterial hypercapnia, some cardiovascular neurons and respiratory neurons have increased activities as well as increased reponses to C-Hber stimulation.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.5
• /
• pp.629-636
• /
• 1999

Gonadal development, gametogenesis, reproductive cycle, egg-diameter and composition, condition factor, and the first sexual maturity of the clam, Potamocorbula amurensis were investigated by histological observation. Samples were collected monthly from the tidal flat of Moonpo, Puan-gun, Chollabuk-do, west coast of Korea from November 1996 to October 1997. P. amurensis is dioecious and oviparous. The gonads were composed of a number of gametogenic follicles. The oogonia and fully ripe oocytes were $9\~12\mu$m and $50\~60\mu$m in diameter, respectively. Each of the spermatogenic follicle formed stratified layers composed of spermatogonia, spermatocytes spermatids, and spermatozoa in groups on the follicular wall. The reproductive cycle of P. amurensis could be classified into five successive stages: early active, late active, ripe, partially spawned, and recovery. Spawning occurred twice a year from May to July and from September to October, the main spawning seasons also appeared twice a year between May and June, and in October when the water temperatures reached above $18^{\circ}C$. The monthly changes in the condition factor were closely related with the reproductive cycle. Minimum size for the sexual maturation of female and male were 8.1 mm in shell length. There were two patterns for the gametogenesis: 1. After spawning, the undischarged ripe oocytes and spermatozoa in the follicles were degenerated and absorbed, but in part, the existing follicles were not contracted significantly and then they took part in new gametogenesis within one or two months (especially, in summer). 2. After spawning, each follicle was contracted, thereafter gametogenesis again occurred in newly formed follicles.

• Journal of Life Science
• /
• v.23 no.6
• /
• pp.832-837
• /
• 2013

In this study, it was investigated the possible mechanisms by which glutamine deprivation exerts its anti-proliferative action in cultured human prostate carcinoma PC3 cells. Glutamine deprivation resulted in inhibition of growth and G2/M arrest of the cell cycle in a time-dependent manner without apoptosis induction, as determined by MTT assay, DAPI staining and flow cytometry analyses. The induction of G2/M arrest by glutamine deprivation was associated with the inhibition of expression of Cdc2, cyclin A and cyclin B1, and up-regulation of the expression of cyclin-dependent kinase (Cdk) inhibitor p21(WAF1/CIP1) in both transcriptional and translational levels. Moreover, glutamine deprivation increased the phosphorylation of checkpoint kinase (Chk)1 and Chk2; however, the levels of Cdc25C phosphorylation were decreased in response to glutamine deprivation in a time-dependent manner. Our data provide a first biochemical evidence that glutamine deprivation suppresses cell viability through G2/M phase arrest without induction of apoptosis in PC3 cells.

• Korean Journal of Animal Reproduction
• /
• v.27 no.1
• /
• pp.53-59
• /
• 2003

For somatic cell nuclear transfer in Hanwoo, fetal fibroblast cell lines were established from 35, 50, 70 and 90-day fetuses of Korean native cattle. The sex of these fetal fibroblast cells were analyzed by PCR using Y-specific primers and confirmed that two cell lines were female and the other two cell lines were male. Karyotyping of these cell lines indicates that the chromosome numbers of fetal fibroblast cells were not affected by passage number and more than 80% of fetal fibroblast cells have normal chromosome number. To evaluate Go stage in cell cycle of fetal fibroblast cells, Western blotting was performed to detect the expression level of PCNA which is known to be expressed in all cell cycle stages except G$_{0}$ stage. Following serum starvation or confluent culture for 7 days, fetal fibroblast cells were effectively reached to G$_{0}$ stage. The cell cycle was resumed after culture of these Go stage-fetal fibroblast cells with normal medium. These results indicates that fetal fibroblast cells originated from Hanwoo were successfully isolated and culture system and induction of cell cycle of these cells were established for somatic cell nuclear transfer in Hanwoo.woo.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.40 no.3
• /
• pp.185-193
• /
• 2013

Mineral trioxide aggregate (MTA) has recently been used as a pulpotomy medicament for primary molars. The aim of this study was to evaluate and compare the proliferation and differentiation potential of dental pulp stromal cells of permanent teeth and deciduous teeth cultured on MTA-coated surface. Human dental pulp stromal cells were obtained from human permanent premolars and deciduous teeth and cultured on MTA-coated culture plates. The cells were subjected to proliferation assay and cell cycle analysis. Their differentiation potential was evaluated by analysing changes in the mRNA expressions of runt-related transcriptional factor 2 (Runx2) and alkaline phosphatase (ALP). Morphological changes of cells in direct contact with MTA were observed using scanning electron microscopy (SEM). The proliferation rates, distribution of cell cycles and mRNA expression patterns of Runx2 and ALP were similar in both types of pulpal cells. SEM observations revealed that both types changed into more dendrite-like cells. On the surface of MTA, human dental pulp stromal cells from deciduous and permanent teeth were able to both proliferate and differentiate into cells that induce mineralization. MTA is suitable as a biocompatible pulpotomy medicament for primary teeth.

• Korean Journal of Ichthyology
• /
• v.6 no.2
• /
• pp.193-205
• /
• 1994

In order to understand fine structural and histochemical changes in the cyst cell and he interstitial cell in the testis of the spottybelly greenling Hexagrammos agrammus associated with the reproductive cycle from January to December, 1992, there cells were studied by electron microscopy and light microscopy. The cyst cells in the mature testis show a weak affinity to haematoxylin. while they become larger in size. At this time, these cells appear to be more functional than those on the growing stage because several mitochondria, endoplasmic reticulum, glycogen particles and a few lipid droplets appear in the cytoplasm of the cyst cell. It appears, therefore, that the cyst cell of this species has vital functions for nutrition, secretion and steroidogenesis. Well-developed interstitial cells contain large rod-shape or spherical mitochondria with tubular cristae and the large quantities of smooth endoplasmic recticulum and electron-dense materials in the vesicle at the mature and spawning stage. The interstitial cells of this species show characteristics of steroid interstitial cells having a vesicular nucleus, mitochondria with tubular cristae, and smooth endoplasmic reticulum. However, these interstitial cells of teleost give negative histochemical reactions for Sudan black B.

• Development and Reproduction
• /
• v.12 no.3
• /
• pp.243-250
• /
• 2008

Mast cells containing a variety of mediators in their cytoplasmic granules are widely distributed in connective tissues and mucosal surfaces of skin, airways, and guts. Within these tissues, mast cells are involved in the pathophysiological conditions such as inflammation, self-defense, tissue-remodeling, and autoimmunity. In order to understand the functional roles of master cells in the uterus, we histologically examined the distribution and density of uterine mast cells in the different aged mice. Until 6 weeks mast cells were sparsely detected in the uterus. But at 7 weeks after birth, when estrous cycle begins, the number of mast cells within uterine tissues increased dramatically and the increment of mast cell density continued up to 32 weeks-age. After then, uterine glandular tissue degenerated gradually and density of uterine mast cell decreased. Uterine mast cells were mainly found in the myometrium and they were closely associated with smooth muscle cells, fibroblasts, and collagens, which contents were changed according to the uterine development in the myometrium. These results suggest that uterine mast cells could be involved in myometrial contractions mediated by smooth muscle cells and tissue reconstitution or remodeling during estrous cycle and parturition including the various immunological functions.

• Journal of Gastric Cancer
• /
• v.5 no.4 s.20
• /
• pp.260-265
• /
• 2005

Purpose: The protein kinase Chk1 is required for cell cycle arrest in response to DNA damage and is shown to play an important role in the G2/M checkpoint. The aim of this study was to investigate the relationship between microsatellite instability and frameshift mutation of the Chk1 gene in gastric cancers. Materials and Methods: The microsatellite instability was analyzed in 95 primary gastric carcinomas by using microdissection and 6 microsatellite markers. We also peformed single strand conformational polymorphism and sequencing to detect frameshift mutation of the Chk1 gene. Results: We found positive microsatellite instability in 19 (20%) of the 95 gastric cancers, 13 high- and 6 low-frequency microsatellite instability cases. The frameshift mutation of Chk1, which resulted in a truncated Chk1 protein, was detected in two high-frequency microsatellite instability cases. Conclusion: These data suggest that the microsatellite instability may contribute to the development of gastric carcinomas through inactivation of Chk1.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.5
• /
• pp.823-833
• /
• 1997

To clarify the annual reproductive cycle of the banded catfish, Pseudobagrus fulvidraco (Richardson), the seasonal changes in histological aspect of gonad and liver were examined. The adult fish was raptured from the upper stream of Young-San river, Chunnam in each month from May 1992 to June 1993. Based on the annual changes in GSI (gonadosomatic index), HSI (hepatosomatic index), CF (condition factor) and histological aspects of the gonads, the annual reproductive cycle were classified into 5 periods as follows: 1) Growing phase (from April to early May): The value of GSI increased and the size of oocytes in perinucleolus stage in oocytes increased gradually. Spermatogonia were developed actively from the epithelial tissues of seminiferous tubules. 2) Maturing phase (from Hay to early June): GSI levels increased rapidly in both sex. Oocytes at various developmental stages were observed. Appearance of active spermatogenesis were observed. 3) Mature and spawning phase (from June to August): High values of GSI remained static and oocytes accumulated significant quantitis of yolk globules. 4) Degenerating phase (from September to November): GSI levels decreased and ovaries were filled mostly with oocytes at the perinucleolus stage. Hepatic cells accumulated significant amounts of lipid droplets. 5) Resting period (from December to March) : Low values of GSI were kept and the size of oocytes at the perinucleolus stage did not increase. Spermatogenesis was not observed.