• Clinical and Experimental Reproductive Medicine
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• 제31권1호
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• pp.19-27
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• 2004

Objective: This study was to examine the in vitro neural cell differentiation patterns of human embryonic stem (hES) cells following treatment of various neurotrophic factors [basic fibroblast growth factor (bFGF), retinoic acid (RA), brain derived neurotrophic factor (BDNF) and transforming growth factor (TGF)-$\alpha$], particulary in dopaminergic neuron formation. Methods: The hES cells were induced to differentiate by bFGF and RA. Group I) In bFGF induction method, embryoid bodies (EBs, for 4 days) derived from hES were plated onto gelatin dish, selected for 8 days in ITSFn medium and expanded at the presence of bFGF (10 ng/ml) for another 6 days followed by a final differentiation in N2 medium for 7, 14 and 21 days. Group II) For RA induction, EBs were exposed of RA ($10^{-6}M$) for 4 days and allowed to differentiate in N2 medium for 7, 14 and 21 days. Group III) To examine the effects of additional neurotrophic factors, bFGF or RA induced cells were exposed to either BDNF (10 ng/ml) or TGF-$\alpha$ (10 ng/ml) during the 21 days of final differentiation. Neuron differentiation and dopamine secretion were examined by indirect immunocytochemistry and HPLC, respectively. Results: The bFGF or RA treated hES cells were resulted in similar neural cell differentiation patterns at the terminal differentiation stage, specifically, 75% neurons and 11% glial cells. Additionally, treatment of hES cells with BDNF or TGF-$\alpha$ during the terminal differentiation stage led to significantly increased tyrosine hydroxylase (TH) expression of a dopaminergic neuron marker, compared to control (p<0.05). In contrast, no effect was observed on the rate of mature neuron (NF-200) or glutamic acid decarboxylase-positive neurons. Immunocytochemistry and HPLC analyses revealed the higher levels of TH expression (20.3%) and dopamine secretion (265.5 $\pm$ 62.8 pmol/mg) in bFGF and TGF-sequentially treated hES cells than those in $\alpha$ RA or BDNF treated hES cells. Conclusion: These results indicate that the generation of dopamine secretory neurons from in vitro differentiated hES cells can be improved by TGF-$\alpha$ addition in the bFGF induction protocol.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 추계 학술대회논문집
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• pp.83-88
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• 2006

Natural convection flows in a cubical air-filled cavity that has one pair of opposing faces isothermal at different temperatures, $T_h\;and\;T_c$ respectively, the remaining four faces having a linear variation from $T_c\;to\;T_h$ are numerically simulated by a solution code(PowerCFD) using unstructured cell-centered method. An extension to a previously published work, special attention of this work is paid to three-dimensional flow and thermal characteristics in nature convection according to new orientation at Ra= $1{\times}105$. Comparisons of the average Nusselt number at the cold face are made with benchmark solutions and experimental results found in the literature. It is demonstrated that the average Nusselt number on the cold face has a maximum value around the diamond-type inclination angle of $43.2^{\circ}\;at\;Ra=1{\times}105$. We also report the effect of new orientation on the type of flow and temperature structure in a cubical-cavity.

• The Korean Journal of Physiology and Pharmacology
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• 제23권6호
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• pp.501-508
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• 2019

Rosmarinic acid (RA) is a natural polyphenolic compound that exists in many medicinal species of Boraginaceae and Lamiaceae. The previous studies have revealed that RA had therapeutic effects on hepatocellular carcinoma (HCC) in the H22-xenograft models by inhibiting the inflammatory cytokines and $NF-{\kappa}B$ p65 pathway in the tumor microenvironment. However, its molecular mechanisms of immunoregulation and pro-apoptotic effect in HCC have not been fully explored. In the present study, RA at 75, 150, and 300 mg/kg was given to H22 tumor-bearing mice via gavage once a day for 10 days. The results showed that RA can effectively inhibit the tumor growth through regulating the ratio of $CD4^+/CD8^+$ and the secretion of interleukin (IL)-2 and interferon-${\gamma}$, inhibiting the expressions of IL-6, IL-10 and signal transducer and activator of transcription 3, thereby up-regulating Bax and Caspase-3 and down-regulating Bcl-2. The underlying mechanisms involved regulation of immune response and induction of HCC cell apoptosis. These results may provide a more comprehensive perspective to clarify the anti-tumor mechanism of RA in HCC.

• 생명과학회지
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• 제22권8호
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• pp.1034-1040
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• 2012

활막조직은 관절부위에 존재하는 비연골성의 얇은 세포층으로 구성되어 있으며, 류마티스 관절염 등에서 활성화 되어진다. 우리는 골관절염(n=8)과 류마티스 관절염(n=5)에서 유래한 활막조직을 대상으로 활막조직내의 세포를 정량화하고 세포성분들을 비교 분석하고자 하였다. 활막조직을 H&E 염색한 후 광학현미경으로 관찰하였을 때 류마티스 관절염의 활막조직은 골관절염에 비해 형태적으로 두터워졌으며 비후된 양상이었다. 또한 CD68, CD90, PGP9.5 등과 마커들을 이용하여 IHC 분석을 수행한 결과 활막조직의 내막층과 내막하층에 존재하는 세포들을 특성을 분한 결과 내막층에는 대식세포가 집중적으로 분포하며, 내막하층에는 대식세포와 섬유아세포 유사 활막세포(FLS)가 존재한다는 사실을 알 수 있었다. H&E 이미지를 포토샵 프로그램을 이용하여 반전시켜 내막층과 내막하층 부위별로 세포계수 및 세포층계수를 수행하였다. 내막층 분석 결과 류마티스 관절염의 활막조직의 골괄절염보다 대식세포의 수와 층이 현저하게 증가된 것을 확인할수 있었다. 또한 류마티스 관절염의 활막조직의 내막하층분석결과 섬유아세포 유사 활막세포의 수적인 증가를 계수 할 수 있었다. 또한 류마티스 관절염의 경우 활막의 비후가 심하기 때문에 혈관의 위치가 내막층으로부터 상대적으로 멀리 위치하고 있음을 알 수 있었다. 그러므로 H&E 염색 이미지의 포토샵 분석을 이용한 골관절염과 류마티스 관절염 활막조직에 대한 정량 분석 방법은 류마티스 관절염의 발병과정에서 세포들이 활성화된다는 사실을 증명하는데 유용할 것으로 사료된다.

• 소성∙가공
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• 제25권5호
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• pp.306-312
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• 2016

Effects of manufacturing conditions, such as austenitizing temperature, patenting temperature and carbon content in steels, on mechanical properties, especially on reduction of area (RA), of hyper-eutectoid steel wires were investigated. RA increased and then decreased with transformation temperature. This was attributed to the presence of abnormal structures in steels transformed at low transformation temperatures and the occurrence of shear cracking during tensile testing of steels transformed at high transformation temperatures. The increase of austenitizing temperature resulted in the increased austenite grain size and consequently the decrease of RA. The decrease of RA with increasing the carbon content in steels was attributed to the increased fraction of cleavage fracture in tensile fractured surfaces.

• 생명과학회지
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• 제20권5호
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• pp.655-661
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• 2010

흑색종세포주 SK-MEL-2에서 레티노이드에 의한 GD3합성효소(hST8Sia I)의 발현억제기작을 규명하게 위하여 hST8Sia I의 프로모터 활성을 조사해 본 결과 -1146에서 -646영역에서 레티노이드에 의한 활성억제를 나타내었다. 또한 부위특이적 변이와 ChIP분석은 -731에서 -722영역에 위치한 전사인자NF-kB 결합부위가 hST8Sia I의 레티노이드에 의한 활성억제에 중요하게 관여하고 있음을 나타내었다. 이러한 발현 억제는 PKC/ERK 신호전달경로를 통하여 일어난다는 것을 신호전달경로 저해제를 이용한 RT-PCR과 프로모터 활성조사에 의해 규명하였다.

• IMMUNE NETWORK
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• 제1권1호
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• pp.36-44
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• 2001

Background : Peritoneal metastasis is one of the maj or types of the stomach cancer recurrence and the role of the adhesion molecules is thought to be very much important in this event. Retinoic acid (RA) has been known to induce the growth inhibition and differentiation of various malignancies, and apoptpsis and the change of expression of adhesion molecules have been reported to be involved in the action of RA. Methods : We studied the adhesion abilities of SNU-1, SNU-5, and SNU-6 cells to the peritoneal endothelial cells as well as the expression of the adhesion molecules (CD44, ICAM-1) in Western blot analysis. And also we studied the expression of apoptosis and the change of expression patterns of the various isoforms of CD44 and the change of the adhsion abilities of the cell line cells after RA treatment. Results: CD44 was expressed in SNU-5 and -16, together with an isoform in SNU-16. ICAM-1 was not expressed in any of the cell line cells tested. After the treatment of RA in the concentration range of $1-5{\times}10^{-5}M$ to three stomach cancer cell lines, growth inhibition, apoptosis and the change of expression of the CD44 were noted. After RA treatment, the expression of CD44H was weakly increased in SNU-1, and was markedly increased in SNU-5. In SNU-16, the expression of CD44H was decreased while that of CD44E were markedly increased. The adhesibility of cells to peritoneal cells was increased in relation with the increase of the CD44H expression, which shows the fact that the adhesibility of tumor cells to peritoneal mesothelial cells is mediated by CD44H recognizing hyaluronic acid. Conclusion : RA induces growth inhibition of stomach cancer cell line cells and increase the adhesiblity of stomach cancer cell line cells to peritoneal mesothelium. It is believed that RA decreases the metastatic ability of stomach cancer cells by upregulating the CD44H expression.

• Journal of Microbiology and Biotechnology
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• 제7권1호
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• pp.62-67
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• 1997

To enhance the hyperproductive and low energy-consuming ethanol fermentation rate, the thermotolerant yeast S. cerevisiae RA-74-2 cells were immobilized. An efficient immobilization condition was proved to be $1.5{\%}$ (w/v) alginate solution, neutral pH and 20 h activation of beads. The fermentation characteristics and stability at various temperatures were examined as compared with free S. cerevisiae RA-74-2 cells. The immobilized cells had excellent fermentation rate at the range of pH 3-7 at 30-$42^{\circ}C$ in 15-$20{\%}$ glucose media. When the seed volume was adjusted to 0.12 (v/v) (6ml bead/50 ml medium), $11{\%}$ (w/v) ethanol was produced during the first 34 hand $12.15{\%}$ (w/v) ethanol [$95{\%}$ (w/v) of theoretical yield] during the first 60 h in $25{\%}$ glucose medium. In repetitive fermentation using a 2 litre fermentor, 5.79-$7.27{\%}$ (w/v) ethanol [76-$95{\%}$ (w/v) of theoretical yield] was produced during the 40-55 h in $15{\%}$ glucose media. These data suggested the fact that alginate beads of thermotolerant S. cerevisiae RA-74-2 cells would contribute to economic and hyperproductive ethanol fermentation at high temperature.

• Macromolecular Research
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• 제14권1호
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• pp.66-72
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• 2006

The purpose of this study is to develop novel nanoparticles based on polyion complex formation between low molecular weight water-soluble chitosan (LMWSC) and all-trans retinoic acid (atRA). LMWSC nanoparticles encapsulating atRA based on polyion complex were prepared by mixing of atRA into LMWSC aqueous solution using ultrasonication. In FTIR spectra, the carbonyl group of atRA at 1690 $cm^{-1}$ disappeared or decreased when ion complexes were formed between LMWSC and atRA. In ${1}^H$ NMR spectra, specific peaks of atRA disappeared when atRA-encapsulated LMWSC (RAC) nanoparticles were reconstituted into $D_{2}O$ while specific peaks both of atRA and LMWSC appeared in $D_{2}O$/DMSO (1/3, v/v) mixture. XRD patterns also showed that the crystal peaks of atRA were disappeared by encapsulation into LMWSC nanoparticles. LMWSC nanoparticles encapsulating atRA have spherical shapes with particle size below 200 nm. The mechanism of encapsulation of atRA into LMWSC nanoparticles was thought to be an ion complex formation between LMWSC and atRA. LMWSC nanoparticles showed high atRA loading efficiency over 90$\%$ (w/w). AtRA was continuously released from nanoparticles over 10 days. In in vitro cell cytotoxicity test, free atRA showed higher cytotoxic effect against CT 26 colon carcinoma cell line on 1 day. However, RAC nanoparticles showed similar cytotoxicity against CT 26 cells on 2 day. These results suggest the potential for the introduction of LMWSC nanoparticles into various biomedical fields such as drug delivery.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.95-95
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• 2002

Human embryonic stem (hES) cells can be induced to differentiate into tyrosine hydroxylase expressing (TH+) cells that may serve as an alternative for cell replacement therapy for Parkinson's disease (PD). To examine in vitro differentiation of hES (MB03, registered in NIH) cells into TH+ cells, hES cells were induced to differentiate according to the 4-/4+ protocol using retinoic acid (RA), ascorbic acid (AA), and/or lithium chloride (LiCl) followed by culture in N2 medium for 14 days, during which time the differentiation occurs. Immunocytochemical stainings of the cells revealed that approximately 21.1% of cells treated with RA plus AA expressed TH protein that is higher than the ratio of TH+ cells seen in any other treatment groups (RA, RA+LiCl or RA+AA+LiCl). In order to see the differentiation pattern in vivo and the ability of in vitro differentiation-induced cells in easing symptomatic motor function of PD animal model, cells (2 $\times$ 10$^{5}$ cells/2${mu}ell$) undergone 4-/4+ protocol using RA plus AA without any further treatment were transplanted into unilateral striatum of MPTP-lesioned PD animal model (C57BL/6). Following the surgery, motor behavior of the animals was examined by measuring the retention time on an accelerating rotar-rod far next 10 weeks. No significant differences in retention time of the animals were noticed until 2 weeks post-graft; however, it increased markedly at 6 weeks and 10 weeks time point after the surgery. Immunohistochemical studies confirmed that a reasonable number of TH+ cells were found at the graft site as well as other remote sites, showing the migrating nature of embryonic stem cells. These results suggest that in viかo differentiated hES cells relieve symptomatic motor behavior of PD animal model and should be considered as a promising alternative for the treatment of PD.