• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.213-217
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• 1997

In this study, three-dimensional inite element model was developed and analyzed or DAI using ABAQUS. To verify the developed FE model, simulated results were compared to experimental results of human cadaver by Nahum et. al. (1977). The effect of acceleration pattern and accelerating duration time or DAI was analyzed by means of maximum shear stress and pressure distribution. DAI was favored or angular acceleration rather than linear acceleration, and occured in brain stem, pons and midbrain easily as accelerating duration time was increased.

• Journal of Ship and Ocean Technology
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• 제10권4호
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• pp.12-23
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• 2006

In this paper, a numerical study is carried out to investigate the turbulent flow around a twin-skeg container ship model with rudders including propeller effects. A commercial CFD code, FLUENT is used with body forces distributed on the propeller disk to simulate the ship stem and wake flows with the propeller in operation. A multi-block, matching, structured grid system has been generated for the container ship hull with twin-skegs in consideration of rudders and body-force propeller disks. The RANS equations for incompressible fluid flows are solved numerically by using a finite volume method. For the turbulence closure, a Reynolds stress model is used in conjunction with a wall function. Computations are carried out for the bare hull as well as the hull with appendages of a twin-skeg container ship model. For the bare hull, the computational results are compared with experimental data and show generally a good agreement. For the hull with appendages, the changes of the stem flow by the rudders and the propellers have been analyzed based on the computed result since there is no experimental data available for comparison. It is found the flow incoming to the rudders has an angle of attack due to the influence of the skegs and thereby the hull surface pressure and the limiting streamlines are changed slightly by the rudders. The axial velocity of the propeller disk is found to be accelerated overall by about 35% due to the propeller operation with the rudders. The area and the magnitude of low pressure on the hull surface enlarge with the flow acceleration caused by the propeller. The propellers are found to have an effect on up to the position where the skeg begins. The propeller slipstream is disturbed strongly by the rudders and the flow is accelerated further and the transverse velocity vectors are weakened due to the flow rectifying effect of the rudder.

• Parasites, Hosts and Diseases
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• 제52권2호
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• pp.151-162
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• 2014

The technique of stem cells or hepatocytes transplantation has recently improved in order to bridge the time before whole-organ liver transplantation. In the present study, unfractionated bone marrow stem cells (BMSCs) were harvested from the tibial and femoral marrow compartments of male mice, which were cultured in Dulbecco's modified Eagle's medium (DMEM) with and without hepatocyte growth factor (HGF), and then transplanted into Schistosoma mansoni- infected female mice on their 8th week post-infection. Mice were sacrificed monthly until the third month of bone marrow transplantation, serum was collected, and albumin concentration, ALT, AST, and alkaline phosphatase (ALP) activities were assayed. On the other hand, immunohistopathological and immunohistochemical changes of granuloma size and number, collagen content, and cells expressing OV-6 were detected for identification of liver fibrosis. BMSCs were shown to differentiate into hepatocyte-like cells. Serum ALT, AST, and ALP were markedly reduced in the group of mice treated with BMSCs than in the untreated control group. Also, granuloma showed a marked decrease in size and number as compared to the BMSCs untreated group. Collagen content showed marked decrease after the third month of treatment with BMSCs. On the other hand, the expression of OV-6 increased detecting the presence of newly formed hepatocytes after BMSCs treatment. BMSCs with or without HGF infusion significantly enhanced hepatic regeneration in S. mansoni-induced fibrotic liver model and have pathologic and immunohistopathologic therapeutic effects. Also, this new therapeutic trend could generate new hepatocytes to improve the overall liver functions.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.77-77
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• 2003

Chimeric animals are referred to as an organism composed of tissues derived from more than one species. In order to examine if a pluripotency of embryonic stem cells can cross the limitation of a species, we tried to establish human-mouse chimeric animals. Human embryonic stem cells were genetically modified to express eGFP using eukaryonic expression vector pcDNA 3.1 (In Vitrogene) for an easy identification. After selection with neomycin, approximately 15 cells were implanted into mouse blastocoele cavity. Ten chimeric blastocysts were transferred to one of the uterine horn of 2.5 days pesudopregnent ICR female. Out of 272 blastocysts transferred to pseudopregnant recipients 20 live newborn were obtained after 20 days. When newborn were obtained, pups were quickly removed immersed into 4% PFA. By histological examination using fluorescent microscope, green fluorescence was observed from the liver, heart, and spleen in newborn mice. Three weeks after born, presence of eGFP sequence within mouse genome (tail and kidney) was reconfirmed by PCR. eGFP sequence was amplified from the progenies of the animal suggesting a genetic transmission of the transgene. These chimeric mice having human cells at the beginning of development, are expected to recognize human cells as “self”, therefore, human cells or tissues will be able to escape the immunological surveillance of the host if grafted into the animal. These animals will serve as a good model system for studying the graft rejection in tissue transplantation and the potential of the cells to work well in many human disease.

• 대한간호학회지
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• 제45권5호
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• pp.694-703
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• 2015

Purpose: This study was a prospective longitudinal study to identify changes in quality of life in patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT). It was based on Roy's adaptation model. Methods: The questionnaires were administered before HSCT, 30 and 100 days after HSCT. Of the 48 potentially eligible patients, 44 (91.7%) participated in the study and 40 (90.9%) completed the questionnaires at 100 days after HSCT. Multilevel analysis was applied to analyze changes in quality of life. Results: Overall, quality of life showed a decreasing tendency from pre-HSCT to 100 days after HSCT. The adaptation level of participants was compensatory. Type of conditioning was the significant factor influencing quality of life before HSCT (${\beta}_{00}$=79.92, p <.001; ${\beta}_{01}$= - 12.64, p <.001) and the change rate of quality of life (${\beta}_{10}$= - 1.66, p =.020; ${\beta}_{11}$=2.88, p =.014). Symptom severity (${\beta}_{20}$= - 1.81, p =.004), depression (${\beta}_{30}$= - 0.58, p =.001), social dependency (${\beta}_{40}$= - 0.35, p =.165), and loneliness (${\beta}_{50}$= - 0.23, p =.065) had a negative effect on changes in quality of life. Symptom severity and depression were statistically significant factors influencing changes in quality of life. Conclusion: According to the results of this study, the development of nursing intervention is needed to improve quality of life in patients undergoing allogeneic hematopoietic stem cell transplantation in the early immune reconstruction period. The interventions should include programs to enhance coping capacity and programs to help control symptom severity and depression. Also these interventions need to be started from the beginning of HSCT and a multidisciplinary approach would be helpful.

• BMB Reports
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• 제51권10호
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• pp.514-519
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• 2018

Ovarian cancer is the most fatal gynecological malignancy in women and identification of new therapeutic targets is essential for the continued development of therapy for ovarian cancer. TRRAP (transformation/transcription domain-associated protein) is an adaptor protein and a component of histone acetyltransferase complex. The present study was undertaken to investigate the roles played by TRRAP in the proliferation and tumorigenicity of ovarian cancer stem cells. TRRAP expression was found to be up-regulated in the sphere cultures of A2780 ovarian cancer cells. Knockdown of TRRAP significantly decreased cell proliferation and the number of A2780 spheroids. In addition, TRRAP knockdown induced cell cycle arrest and increased apoptotic percentages of A2780 sphere cells. Notably, the mRNA levels of stemness-associated markers, that is, OCT4, SOX2, and NANOG, were suppressed in TRRAP-silenced A2780 sphere cells. In addition, TRRAP overexpression increased the mRNA level of NANOG and the transcriptional activity of NANOG promoter in these cells. Furthermore, TRRAP knockdown significantly reduced tumor growth in a murine xenograft transplantation model. Taken together, the findings of the present study suggest that TRRAP plays an important role in the regulation of the proliferation and stemness of ovarian cancer stem cells.

• 생명과학회지
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• 제22권5호
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• pp.621-626
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• 2012

초파리는 발생과 질병연구를 위한 모델 곤충으로 널리 이용되어 왔다. 본 연구에서도 초파리를 모델곤충으로 한 장질환 연구의 일환으로 다양한 병원균 감염 및 장질환 유발시 어떻게 장줄기세포가 작용하는지를 이해하기 위해 초파리 장세포의 일차배양 방법을 확립하였다. 초파리 성충으로부터 장을 해부하고 다양한 효소를 처리하여 장세포를 분리한 후 배양하였다. 배양세포의 생존여부는 현미경 검경 및 MTS assay에 의해 확인한 결과 배양 후 9일째 최대 증식되었고 14일까지 생존함을 확인할 수 있었다. 또한 장줄기세포 및 장내분비세포의 존재도 immunostaining에 의해 확인하였다. 따라서 본 연구에서 구축된 초파리 일차배양 장세포는 다양한 유전자에 의한 장줄기 세포 조절연구뿐만 아니라 장에서 발생하는 다양한 질병을 연구하는 도구로 매우 유용할 것으로 추측된다.

• Journal of Plant Biotechnology
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• 제44권3호
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• pp.229-234
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• 2017

Photoperiod is one of the factors affecting productivity of cucumber plant by inducing ethylene hormone production and so triggering flower sex differentiation into female flower. However, only few studies have been perfomed in order to reveal the effect of photoperiod in molecular level in relation to the flower differentiation. Therefore, in this study, Mercy cultivar of cucumber (andromonoecious) was treated with photoperiod of 8, 12, 16 hours of light, while control received no treatment of additional light. Photoperiod of 8 hours was achieved by blocking the sunlight with shade net and 16 hours by giving longer light exposure using white LEDs. Cucumber's flowers were quantified and the apical and lateral shoots were extracted to evaluate the gene profile related to the photoperiod, ethylene production, and female flower differentiation, which were CsACS2, CsETR1, CsCaN, and CsPIF4 using PCR method. Photoperiod of 8 hours affected the production of female flower with average number of 6.7 flowers in main stem and 8.0 flowers in lateral stem, compared to photoperiod of 12 and 16 hours which produced 3.7 and 2.0 flowers in main stem with 7.0 and 11.3 in lateral stem, respectively. In silico studies in this experiment resulted in proposed model of signal transduction that showed the connection between ethylene production and flower differentiation. PCR analysis confirmed the expression of CsACS2, CsETR1, and CsCaN, that was positively correlated with numbers of female flowers in cucumber, but the expression of CsPIF4 that represent photoperiod haven't been confirmed correlated with the ethylene production and flower differentiation.

• 대한한의학회지
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• 제37권4호
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• pp.36-44
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• 2016

Objectives: Granulocyte-colony-stimulating factor (G-CSF) mobilized bone marrow (BM)-derived hematopoietic stem cells could contribute to improvement of liver function. In addition, liver fibrosis can reportedly be prevented by the Rg 1 component of red ginseng. This study investigated the combined effect of G-CSF and red ginseng on decompensated liver cirrhosis. Methods: Four patients with decompensated liver cirrhosis were injected with G-CSF to proliferate BM stem cells for 4 days ($5{\mu}g/kg$ bid subcutaneously) and followed-up for 3 months. The patients also received red ginseng for 4 days (2 tablets tid per os). We analyzed Child-Pugh scores, Model for End-Stage Liver Disease (MELD) scores and cirrhotic complications. Results: All patients showed marked increases in White blood cell (WBC) and CD34+ cells in the peripheral blood, with a peak time of 4 days after G-CSF injection. Spleen size also increased after G-CSF injection, but not severely. At end of the study, 2 patients showed improvement in Child-Pugh scores, hepatic encephalopathy, and refractory ascites. During the clinical trial period, none of the 4 patients showed any other adverse events or deterioration of liver function. Conclusions: We conclude that G-CSF/red ginseng combination therapy is relatively effective in improving liver function and major complications of decompensated liver cirrhosis without adverse effects. Further clinical trials are warranted to assess the clinical effects of G-CSF for decompensated liver cirrhosis.

• The Korean Journal of Pain
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• 제27권3호
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• pp.239-245
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• 2014

Background: Neuropathic pain induced by spinal or peripheral nerve injury is very resistant to common pain killers, nerve block, and other pain management approaches. Recently, several studies using stem cells suggested a new way to control the neuropatic pain. In this study, we used the spinal nerve L5 ligation (SNL) model to investigate whether intrathecal rat mesenchymal stem cells (rMSCs) were able to decrease pain behavior, as well as the relationship between rMSCs and reactive oxygen species (ROS). Methods: Neuropathic pain of the left hind paw was induced by unilateral SNL in Sprague-Dawley rats (n = 10 in each group). Mechanical sensitivity was assessed using Von Frey filaments at 3, 7, 10, 12, 14, 17, and 24 days post-ligation. rMSCs ($10{\mu}l$, $1{\times}10^5$) or phosphate buffer saline (PBS, $10{\mu}l$) was injected intrathecally at 7 days post-ligation. Dihydroethidium (DHE), an oxidative fluorescent dye, was used to detect ROS at 24 days post-ligation. Results: Tight ligation of the L5 spinal nerve induced allodynia in the left hind paw after 3 days post-ligation. ROS expression was increased significantly (P < 0.05) in spinal dorsal horn of L5. Intrathecal rMSCs significantly (P < 0.01) alleviated the allodynia at 10 days after intrathecal injection (17 days post-ligation). Intrathecal rMSCs administration significantly (P < 0.05) reduced ROS expression in the spinal dorsal horn. Conclusions: These results suggest that rMSCs may modulate neuropathic pain generation through ROS expression after spinal nerve ligation.