• Journal of Life Science
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• v.33 no.8
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• pp.612-622
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• 2023

T-cell deficiency may occur in various clinical conditions including congenital defects, cell/organ transplantation, HIV infection and aging. In this regard, the development of artificial thymus has recently been attracting much attention. To achieve this aim, the development of techniques for 3D culture of thymic stromal cells is necessary because thymocytes grown only in a 3D thymic microenvironment can be differentiated fully to become mature, immunocompetent T cells; the same cannot be achieved for thymocytes grown in 2D. This study aimed to develop a nanotechnology-based 3D culture technique using polymeric scaffolds for thymic epithelial cells (TECs), the main component of thymic stromal cells. Scanning electron microscopic observation revealed that the pores of both PCL and PCL/PLGA scaffolds were filled with TECs. Interestingly, TECs grown in 3D on polydopamine-coated scaffolds exhibited enhanced cell attachment and proliferation compared to those grown on non-coated scaffolds. In addition, the gene expression of thymopoietic factors was upregulated in TECs cultured in 3D on polydopamine-coated scaffolds compared to those cultured in 2D. Taken together, the results of the present study demonstrate an efficient 3D culture model for TECs using polymeric scaffolds and provide new insights into a novel platform technology that can be applied to develop functional, biocompatible scaffolds for the 3D culture of thymocytes. This will eventually shed light on techniques for the in vitro development of T cells as well as the synthesis of artificial thymus.

• Journal of Animal Science and Technology
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• v.44 no.6
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• pp.769-782
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• 2002

Three kinds of green forages(rye, oats and mixed forages) was harvested and mixed with rice straw, wheat bran and 2 grains(corn and soybean), which harvested 2 different dates(common harvesting dates, 7 days early to common harvesting dates). And each mixture was ensiled in 6 poly vinyl chlorides that was 60 liter, immediately. They were opened at 0, 5, 10, 25, 35, 60 and 100 days after ensiling for chemical analysis. And its effects of those TMFFs on feed values were observed. Average contents of water, crude protein, ADF, NDF, Ca and P of formulated TMFs were 72 to 75%, 14.75 to 18.24, 12.47 to 19.07, 39.82 to 47.01, 0.99 to 1.07 and 0.38 to respectively. Crude protein content was the highest in the mixed forages-TMFF and the lowest in the rye-TMFF. The ADF and NDF contents of rye-TMFF were higher than orthers. And CP, ADF, NDF, TDN, P and Ca contents were no significant difference among treatments regardless of storage period and harvest time, but all treatments indicated good quality. Intenal temperatures of TMFF were shown to be 1 to 5$^{\circ}C$ higher than ambient temperatures. The temperature of the Oat-TMFF formulated during winter sustained higher to the level of 6${\sim}$9$^{\circ}C$ for 10 days. The pH of TMFF were 4.0 to 4.2 and the content of $NH_3$-N was shown to be 7.79 to 8.23mg/$d{\ell}$. In the VFA contents, any tendency was not shown at all treatments depending on harvest time. Even though rye-TMFF showed the lowest VFA value. At all treatments except rye-TMFF, propionate production was increased and stable after 25 days of storage. Digestibility of rice straw from TMFF on DM basis was 15${\sim}$20% higher compared with non-treated rice straw.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.6
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• pp.465-473
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• 2004

Purpose : The essential triad for nerve regeneration is nerve conduit, supporting cell and neurotrophic factor. In order to improve the peripheral nerve regeneration, we used polyglycolic acid(PGA) tube and brain-derived neurotrophic factor(BDNF) gene transfected Schwann cells in sciatic nerve defects of SD rat. Materials and methods : Nerve conduits were made with PGA sheet and outer surface was coated with poly(lactic-co-glycolic acid) for mechanical strength and control the resorption rate. The diameter of conduit was 1.8mm and the length was 17mm Schwann cells were harvested from dorsal root ganglion(DRG) of SD rat aged 1 day. Schwann cells were cultured on the PGA sheet to test the biocompatibility adhesion of Schwann cell. Human BDNF gene was obtained from cDNA library and amplified using PCR. BDNF gene was inserted into E1 deleted region of adenovirus shuttle vector, pAACCMVpARS. BDNF-adenovirus was multiplied in 293 cells and purified. The BDNF-Adenovirus was then infected to the cultured Schwann cells. Left sciatic nerve of SD rat (250g weighing) was exposed and 14mm defects were made. After bridging the defect with PGA conduit, culture medium(MEM), Schwann cells or BDNF-Adenovirus infected Schwann cells were injected into the lumen of conduit, respectively. 12 weeks after operation, gait analysis for sciatic function index, electrophysiology and histomorphometry was performed. Results : Cultured Schwann cells were well adhered to PGA sheet. Sciatic index of BDNF transfected group was $-53.66{\pm}13.43$ which was the best among three groups. The threshold of compound action potential was between 800 to $1000{\mu}A$ in experimental groups which is about 10 times higher than normal sciatic nerve. Conduction velocity and peak voltage of action potential of BDNF group was the highest among experimental groups. The myelin thickness and axonal density of BDNF group was significantly greater than the other groups. Conclusion : BDNF gene transfected Schwann cells could regenerate the sciatic nerve gap(14mm) of rat successfully.

• Journal of the Korea Institute of Building Construction
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• v.9 no.4
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• pp.63-73
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• 2009

Recently, the use of lightweight panels in building structures has been increasing. Of the various lightweight panel types, styrofoam sandwich panels are inexpensive and are excellent in terms of their insulation capacity and their constructability. However, sandwich panels that include organic material are quite vulnerable to fire, and thus can numerous casualties in the event of a fire due to the lack of time to vacate and their emission of poisonous gas. On the other hand, lightweight foamed concrete is excellent, both in terms of its insulation ability and its fire resistance, due to its Inner pores. The properties of lightweight concrete is influenced by foaming agent type. Accordingly, this study investigates the insulation properties by foaming agent type, to evaluate the possibility of using light-weight foamed concrete instead of styrene foam. Our research found thatnon-heating zone temperature of lightweight foamed concrete using AP (Aluminum Powder) and FP (animal protein foaming agent) are lower than that of light-weight foamed concrete using AES (alkyl ether lactic acid ester). Lightweight foamed concrete using AES and FP satisfied fire performance requirements of two hours at a foam ratio 50, 100. Lightweight foamed concrete using AP satisfied fire performance requirements of two hours at AP ratio 0.1, 0.15. The insulation properties were better in closed pore foamed concrete by made AP, FP than with open pore foamed concrete made using AES.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.4
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• pp.285-291
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• 2012

Purpose: This study was conducted to identify the surface characteristics of titanium discs coated with MS275/PLGA by electrospray and which is effective to mesenchymal stem cell proliferation. Materials and methods: We used anodized surface coated with PLGA as a control group and anodized surface coated with MS275 $0.5{\mu}M$, $1{\mu}M$, $1.5{\mu}M$ as test groups. To examine that the coating particles are nanometer sized, FE-SEM was used and AFM was utilized to determine the difference of coating surface roughness. We checked the mesenchymal stem cell proliferation by using MTT assay on $1^{st}$, $4^{th}$, $7^{th}$ days. Results: There was no significant difference between control groups and test groups in AFM results (P>.05). In MTT assay results, mesenchymal stem cell proliferation was increased with time, at $7^{th}$ day, cell viability on discs coated with $1.5{\mu}M$ MS275 was significantly higher than control group (P<.05). As SEM showed, the number of cells on all discs was increased and the morphology of cell attachment was also wider and closer with time. Conclusion: Titanium surface coated with MS275/PLGA showed significantly higher cell proliferation and the more density of MS275 was dispersed on titanium discs, the faster cells grew.