• 대한기계학회논문집A
• /
• 제28권8호
• /
• pp.1183-1189
• /
• 2004

A novel cell count method, which can improve the count efficiency and reduce contamination problem, was presented using micro lattice engraved on culture dish. The micro lattice has feature of $50{\mu}m{\times}50{\mu}m$ rectangular shape, $2{\mu}m$ line width, and $2{\mu}m$ depth in $3mm{\times}3mm$ area. In this paper, nickel mold was fabricated with thickness of 3mm and diameter of 80 mm, and transcription of the micro lattice on a polystyrene cell culture dish was performed by hot embossing at $200\;^{\circ}C$. The tedious and error-prone harvest/load processes of conventional cell counts with a hemocytometer could be omitted, and these advantages became magnified during periodical counts involving long-term cultures. SupT1 cells and HeLa cells were cultivated with the dish for 7 days in $CO_2$ incubator and counted as $371.84/mm^2$ and $123.36/mm^2$, respectively, during the cultivation without harmful effects on the cells.

• IMMUNE NETWORK
• /
• 제16권2호
• /
• pp.99-108
• /
• 2016

Colorectal cancer is the third leading cancer worldwide. Although incidence and mortality of colorectal cancer are gradually decreasing in the US, patients with metastatic colorectal cancer have poor prognosis with an estimated 5-year survival rate of less than 10%. Over the past decade, advances in combination chemotherapy regimens for colorectal cancer have led to significant improvement in progression-free and overall survival. However, patients with metastatic disease gain little clinical benefit from conventional therapy, which is associated with grade 3~4 toxicity with negative effects on quality of life. In previous clinical studies, cell-based immunotherapy using dendritic cell vaccines and sentinel lymph node T cell therapy showed promising therapeutic results for metastatic colorectal cancer. In our preclinical and previous clinical studies, cytokine-induced killer (CIK) cells treatment for colorectal cancer showed favorable responses without toxicities. Here, we review current treatment options for colorectal cancer and summarize available clinical studies utilizing cell-based immunotherapy. Based on these studies, we recommend the use CIK cell therapy as a promising therapeutic strategy for patients with metastatic colorectal cancer.

• Imaging Science in Dentistry
• /
• 제30권2호
• /
• pp.127-131
• /
• 2000

A 19-year-old man was referred to Seoul National University Dental Hospital for evaluation of a large painless swelling of the left mandibular angle area in August, 1999. The growth had been first noted 6 years ago. He had visited other hospital in 1997. In spite of the treatment given at the hospital, the mass continued to grow rapidly. Conventional radiographs in 1999 showed an expansile, lobulated, and destructive lesion of the left mandibular body. CT scan demonstrated an expansile mass with a corticated margin. Bony septa were seen within the lesion. Internal calcification noted on the bone-setting CT image, and corresponded to the hypointense area in T1-weighted MRI image. MRI clearly delineated the extent of the lesion which had heterogenous intermediate signal intensity in T1-weighted images and heterogenous hyperintense signal intensity in T2-weighted images. The lesion was well-enhanced. Histopathologically, the lesion was well demarcated. Multinucleated giant cells were presented in a fibrous background, demonstrating a storiform pattern. Areas of osteoid rimmed by a few osteoblasts were scattered throughout the lesion. Inflammatory cells, blood vessels, and hemosiderin deposition were also shown. CGCG may show lots of internal calcification foci on the CT, and varied signal intensity in MRI. More cases will be needed to understand the features of the CT & MR finding of CGCG.

• Molecules and Cells
• /
• 제43권3호
• /
• pp.304-311
• /
• 2020

Methionyl-tRNA synthetase (MRS) is essential for translation. MRS mutants reduce global translation, which usually increases lifespan in various genetic models. However, we found that MRS inhibited Drosophila reduced lifespan despite of the reduced protein synthesis. Microarray analysis with MRS inhibited Drosophila revealed significant changes in inflammatory and immune response genes. Especially, the expression of anti-microbial peptides (AMPs) genes was reduced. When we measured the expression levels of AMP genes during aging, those were getting increased in the control flies but reduced in MRS inhibition flies age-dependently. Interestingly, in the germ-free condition, the maximum lifespan was increased in MRS inhibition flies compared with that of the conventional condition. These findings suggest that the lifespan of MRS inhibition flies is reduced due to the down-regulated AMPs expression in Drosophila.

• Journal of Ginseng Research
• /
• 제43권4호
• /
• pp.589-599
• /
• 2019

Background: Panax ginseng Meyer is known as a conventional herbal medicine, and ginsenoside Rg1, a steroid glycoside, is one of its components. Although Rg1 has been proved to have an antiobesity effect, the mechanism of this effect and whether it involves adipose browning have not been elucidated. Methods: 3T3-L1 and subcutaneous white adipocytes from mice were used to access the thermogenic effect of Rg1. Adipose mitochondria and uncoupling protein 1 (UCP1) expression were analyzed by immunofluorescence. Protein level and mRNA of UCP1 were also evaluated by Western blotting and realtime polymerase chain reaction, respectively. Results: Rg1 dramatically enhanced expression of brown adipocyte-especific markers, such as UCP1 and fatty acid oxidation genes, including carnitine palmitoyltransferase 1. In addition, it modulated lipid metabolism, activated 5' adenosine monophosphate (AMP)-activated protein kinase, and promoted lipid droplet dispersion. Conclusions: Rg1 increases UCP1 expression and mitochondrial biogenesis in 3T3-L1 and subcutaneous white adipose cells isolated from C57BL/6 mice. We suggest that Rg1 exerts its antiobesity effects by promoting adipocyte browning through activation of the AMP-activated protein kinase pathway.

• Journal of Microbiology and Biotechnology
• /
• 제29권9호
• /
• pp.1444-1452
• /
• 2019

The conventional prophylactic vaccines for human papillomavirus (HPV) efficiently prevent infection with high-risk HPV types, but they do not promote therapeutic effects against cervical cancer. Previously, we developed HPV16 E7-expressing Lactobacillus casei (L. casei-E7) as a therapeutic vaccine candidate for cervical cancer, which induces antitumor therapeutic effects in a TC-1 murine cancer model. To improve the therapeutic effect of L. casei-E7, we performed co-treatment with poly-gamma-glutamic acid (${\gamma}-PGA$), a safe and edible biomaterial naturally secreted by Bacillus subtilis. We investigated their synergistic effect to improve antitumor efficacy in a murine cancer model. The treatment with ${\gamma}-PGA$ did not show in vitro cytotoxicity against TC-1 tumor cells; however, an enhanced innate immune response including activation of dendritic cells was observed. Mice co-administered with ${\gamma}-PGA$ and L. casei-E7 showed significantly suppressed growth of TC-1 tumor cells and an increased survival rate in TC-1 mouse models compared to those of mice vaccinated with L. casei-E7 alone. The administration of ${\gamma}-PGA$ markedly enhanced the activation of natural killer (NK) cells but did not increase the E7-specific cytolytic activity of $CD8^+$ T lymphocytes in mice vaccinated with L. casei-E7. Overall, our results suggest that oral administration of ${\gamma}-PGA$ induces a synergistic antitumor effect in combination with L. casei-E7.

• 대한수의학회지
• /
• 제27권1호
• /
• pp.27-34
• /
• 1987

To verify the direct effects of the thyroid hormone ($T_3$) on the rabbit heart, $T_3$-Tyrode solution in vitro was perfused on the normal atrial muscles and enzymatically isolated ventricular myocytes of the rabbit. All the experimental procedures were conducted at $35^{\circ}C$ and the same procedures were repeated after Ca. 120 minutes from the beginning of $T_3$-Tyrode perfusion. Compared to the state between the normal Tyrode solution and $T_3$-Tyrode solution, results were observed on the same cells by electrophysiological methods (conventional intracellular recording and whole cell patch clamping) as soon as possible. The results obtained were as follows : 1. Action potential duration (APD) on the left atrial muscle was reduced under the perfusion of $T_3$-Tyrode. 2. Absolute refractory Period was shortened by $T_3$-Tryrode perfusion. (117 msec./114 msec., 90 msec./78 msec.) 3. Maximal Ca currents ($i_{Ca}$) were decreased in single: ventricular myocytes under the $T_3$-Tyrode (2.98 nA) than under the normal Tyrode (6.65 nA) 4. On I-V relation, reversal potential was shifted to lower membrane potential and membrane potential showing maximal $i_{Ca}$was lowered from +10mV to -20mV by $T_3$ effect. 5. Above results were likely to explain that tachycardia in the hyperthyroid state was caused in part by the reduced repolarization phase and the reduced refractory period due to the decrease of the Ca current.

• 한국약용작물학회지
• /
• 제22권2호
• /
• pp.134-139
• /
• 2014

This study was to investigate the improvement of immune activities of the extracts from Codonopsis lanceolata by stepwise steaming process and high pressure process. The phenol contents was $8.742{\mu}g/mg$ which was higher than that from conventional extraction using 70% ethyl alcohol at $80^{\circ}C$ for 24 hours. All of extracts at a concentration of $1.0mg/m{\ell}$ showed relatively low cytotoxicity on human normal kidney cell (HEK293) in range of 16 19%. The immune B and T cell growth was improved by extracts using the steamed and high pressure precess of C. lanceolata up to $180{\times}10^4cells/m{\ell}$ and $96{\times}10^4cells/m{\ell}$, respectively. The extract prepared also greatly increased the secretion of both IL-6 and TNF-${\alpha}$ from the stepwise steamed and high pressure process. This results can conclude that stepwise steamed and high pressure process effectively released active biomaterials which could important role in enhancing immune activity in the body.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
• /
• pp.274.2-274.2
• /
• 2013

We described a simple and efficient fabrication method for generating microfluidic channels with a circular-cross sectional geometry by exploiting the reflow phenomenon of a thick positive photoresist. Initial rectangular shaped positive photoresist micropatterns on a silicon wafer, which were fabricated by a conventional photolithography process, were converted into a half-circular shape by tuning the temperature to around $105^{\circ}C$. Through optimization of the reflow conditions, we could obtain a perfect circular micropattern of the positive photoresist, and control the diameter in a range from 100 to 400 ${\mu}m$. The resultant convex half-circular photoresist was used as a template for fabricating a concave polydimethylsiloxane (PDMS) through a replica molding process, and a circular PDMS microchannel was produced by bonding two half-circular PDMS layers. A variety of channel dimensions and patterns can be easily prepared, including straight, S-curve, X-, Y-, and T-shapes to mimic an in vivo vascular network. To inform an endothelial cell layer, we cultured primary human umbilical vein endothelial cells (HUVECs) inside circular PDMS microchannels, and demonstrated successful cell adhesion, proliferation, and alignment along the channel.

• Advances in aircraft and spacecraft science
• /
• 제6권1호
• /
• pp.31-49
• /
• 2019

Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces. This includes aircraft, helicopter blades, engine rotors, buildings and bridges. Flutter occurs as a result of interactions between aerodynamic, stiffness and inertia forces on a structure. The conventional method for designing a rotor blade to be free from flutter instability throughout the helicopter's flight regime is to design the blade so that the aerodynamic center (AC), elastic axis (EA) and center of gravity (CG) are coincident and located at the quarter-chord. While this assures freedom from flutter, it adds constraints on rotor blade design which are not usually followed in fixed wing design. Periodic Structures have been in the focus of research for their useful characteristics and ability to attenuate vibration in frequency bands called "stop-bands". A periodic structure consists of cells which differ in material or geometry. As vibration waves travel along the structure and face the cell boundaries, some waves pass and some are reflected back, which may cause destructive interference with the succeeding waves. In this work, we analyze the flutter characteristics of a helicopter blades with a periodic change in their sandwich material using a finite element structural model. Results shows great improvements in the flutter forward speed of the rotating blade obtained by using periodic design and increasing the number of periodic cells.