On the Convergence of Bio-, Information-, Enrivonmental-, Energy-, Space- and Nano-Technolgies

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Authors: Bo Hyung Park, Young A Han, Jin Hyun Choi, Jeong Ok Lim
Abstract: To replace a poly(2-hydroxyethyl methacrylate) (PHEMA) sponge, which has limited applications as an implant material, PHEMA and poly(2-hydroxyethyl methacrylate-co-sodium methacrylate) (P(HEMA-co-SMA)) hydrogels with enhanced biocompatibility were prepared based on the copolymerization of 2-hydroxyethyl methacrylate (HEMA) and sodium methacrylate (SMA) at a high monomer concentration. When the cytotoxicity, cell adhesion, and in vivo tissue reaction of the resulting hydrogels were investigated, the results suggest that hydrogels prepared by the copolymerization of HEMA and SMA at a high monomer concentration have great potential as implant materials with an excellent biocompatibility.
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Authors: Hai Yan Hong, Jeong Ok Lim, Woon Yi Baek
Abstract: The control of intractable pain through transplanted of chromaffin cells has been recently reported where the analgesic effects are principally due to the production of opioid peptides and catecholamines (CAs) by the chromaffin cells. Currently many cancer patients receive general opioids or local anesthetics, such as bupivacaine. Therefore, the present study investigated the effect of morphine or bupivacaine on the secretion of nicotine-induced CAs from encapsulated chromaffin cells over a period of 180 min. As such, bovine chromaffin cells were isolated and encapsulated with alginate–poly–L–lysine–alginate (APA) biomaterials to prevent immunorejection. The capsules were then pre-incubated with nicotine for 5 min prior to morphine or bupivacaine stimulation, and the quantity of CAs analyzed using a high performance liquid chromatography (HPLC) analysis system. The resulting data showed that the encapsulated chromaffin cells retained the ability of their parent chromaffin cells when responding to opioids by suppressing the release of CAs. In contrast, bupivacaine did not have any statistically significant affect on the basal and nicotine-induced CA release from the encapsulated chromaffin cells.
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Authors: Yu Mi Kim, Young Hoon Jeon, Gwang Chun Jin, Jeong Ok Lim, Woon Yi Baek
Abstract: Intrathecal implants of adrenal medullary chromaffin cells relieve chronic pain by secreting catecholamines, opioids and other neuroactive substances. Recently, macrocapsules with hollow fibers were employed to isolate immunologically xenogeneic chromaffin cells, but the poor viability in vivo of the encapsulated chromaffin cells limited the usefulness of this method. In this study, we used microencapsulation technology to increase the viability of chromaffin cells. Bovine adrenal chromaffin cells were microencapsulated with alginate and poly-L-lysine and implanted intrathecally in a rat using the neuropathic pain model. Intrathecal implants of microencapsulated cells relieved cold allodynia, which is the most prominent symptom of the neuropathic pain model in a rat. Furthermore, the microencapsulated chromaffin cells were morphologically normal and retained their functionality. These findings suggest that the intrathecal implant of microencapsulated chromaffin cells might be a useful method for treating chronic pain.
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Authors: Yongae Kim, Yuna Kim, Jae Joon Park, Jung Hyun Hwang, Tae Joon Park
Abstract: Amyloid fibrils have long been established as the well-known a-helix to b-sheet transition that characterizes the conversion of the cellular form of prion proteins into a scrapie form. A very short sequence of the Yeast prion-like protein GNNQQNY(SupN) is responsible for the aggregation that induces diseases. As such, in the current study, a GST-fused monomer SupN vector is used to express the SupN peptide in Escherichia coli(E. Coli). In addition, a method for the production, purification, and cleavage of the recombinant SupN in E. coli is also described, which yields as much as 2mg per liter of growth of natural abundance fusion proteins in LB media. To gain a better understanding of the aggregation-structure relationship of the 7 residues of the Yeast prion-like protein, the change in the conformational structure is studied by Transmission Electron Microscopy and will be further studied by 13C solid-state NMR. Accordingly, this is the first investigation of the fibril formation of a heptamer peptide expressed in E.coli.
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Authors: Jeong Ok Lim, Won Kiel Lee, Il Soo Park, Jin Seok Hwang, Jeong Min Suh, Woon Yi Baek, Sang Heun Lee
Abstract: A different range of vancomycin was incorporated into a poly dl-lactide-co-glycolide) [PLGA] disc matrix using the hot compression method. The disc was placed in phosphate buffered saline (PBS) and incubated at 37oC. The PBS was changed periodically, and the removed solution was analyzed using high performance liquid chromatography. The sensitivity of the antibiotic-polymer matrix was evaluated using cultured-human-ear methicillin-resistant staphylococcus aureus (MRSA). The MRSA growth was inhibited proportionally to the incorporated vancomycin concentration in the disc matrix. A disc incorporating 400 µg of antibiotics inhibited the growth of MRSA 10 times longer than the disc containing 30 µg as a control. It was found that the biodegradable polymer matrix enabled the control-release of an antibiotic, and the release profile was observed as zero order.
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Authors: Young A Han, Jeong Ok Lim, Jin Hyun Choi, Byung Chul Ji
Abstract: The release behavior of the basic fibroblast growth factor (bFGF) from copolymer hydrogels of N-isopropyl acrylamide (NIPAAm) and sodium methacrylate (SMA) was investigated in relation to the volume phase transition temperatures, which was increased by the incorporation of SMA. In the case of the copolymer hydrogels, a higher volume phase transition temperature was obtained when poly(ethylene glycol) diacrylate (PEGDA) was used as the crosslinking agent, suggesting that the chain length of the crosslinking agent has a significant affect on the volume phase transition temperature of a P(NIPAAm-co-SMA) hydrogel. The concentration of bFGF released from the hydrogels with PEGDA increased relative to the water content, thereby showing a dependence on the volume phase transition temperature. Hence, the release behavior of bFGF from the PNIPAAm and P(NIPAAm-co-SMA) hydrogels was found to be affected by the volume phase transition temperature, which can be easily controlled by changing the comonomer, monomer feed ratio, and crosslinking agent.
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Authors: Hye Jin Yoo, Han Do Kim
Abstract: A series of multiblock polyurethanes containing various poly(ethylene oxide) (PEO) contents (0-80 wt%) were prepared from hexamethylene diisocyanate (HDI)/ PEO / poly(tetramethylene oxide) (PTMO)/ polybutadiene diol (PBD)/ 1,4-butanediol (BD) and used as modifying additives (30 wt%) to improve the properties of biomedical grade PelletheneÒ. A hydrophilic PEO component was introduced by the addition of PEO-containing polyurethanes and dicumyl peroxide (DCP) as the crosslinking agents in a PelletheneÒ matrix. As the PEO content (PEO block length) increased, the hydrogen-bonding fraction of the crosslinked polyurethane also increased, indicating an increase in the phase separation with an increase in the PEO content in the crosslinked polyurethane. Using electron spectroscopy for a chemical analysis, the ratio of ether carbon to alkyl carbon in the crosslinked polyurethane film increased remarkably with an increase, in the PEO content. Meanwhile, the water contact angle of the crosslinked polyurethane film surfaces decreased with increasing PEO content. The water absorption and mechanical properties of the crosslinked polyurethane films increased with increasing and the platelet adhesion on the crosslinked polyurethane film surfaces decreased significantly. Accordingly, these results suggest that the crosslinked polyurethane containing a hydrophilic PEO component may be more effective for a biomaterial application that is in direct contact with blood.
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Authors: Ji Hye Lee, June Moon Jang, Han Sang Cho, Ki Cheol Han, Tae Song Kim, Ji Yoon Kang, Eun Gyeong Yang
Abstract: Microfluidic devices are of considerable interest, since such technology offers great promise for the development of powerful and versatile miniaturized analyzers. Accordingly, the present work describes a microfluidic screening system that is composed of a microchip, hydrodynamic pumping unit and fluorescence detectors. To develop an assay for RNA-aminoglycoside interactions, microchips are designed and fabricated on a glass substrate, then flow simulations are performed in the microchannels. After optimizing the flow control and buffer composition for fluorescence-based biochemical assays, a fluorescently labeled aminoglycoside probe and RNA are allowed to flow continuously to the main micro-channel based on hydrodynamic pumping and their interactions monitored by fluorescence quenching, which is reversed upon competition with other aminoglycosides. Consequently, the proposed device can serve as an integrated microfluidic platform for the high-throughput screening of high affinity antibiotics for RNA targets.
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Authors: Hyun Hee Jung, Joon Mo Yang, Won Myung Woo, Seung Ho Yi, J.S. Yang, Kwang Sup Soh
Abstract: The signal characteristics of the biophotons from human hands were studied using correlation and δ-value analyses. Three healthy individuals without any history of disease participated in the measurements, six times every Friday for 52 weeks, while staying in a room with dim lighting to eliminate any delayed luminescence caused by the sun or room lights. Two head-on type photomultiplier tubes inside a dark room were used to simultaneously measure the biophoton emissions from the palm and dorsum of the left and right hand with a 100ms gate time. In view of the signal process, a cross-correlation of the long-term data, i.e. the weekly measurements, revealed a strong correlation between the signals from the left and right hand, yet only a very weak correlation between the palm and dorsum. The non-classical light property of the biophotons, that has a quantum coherence nature, was compared with that of the dark counts of the PMTs using a δ- value analysis. The average δ-value for the biophotons was 0.08±0.07. As such, it was found that the palm emissions were very coherent, while the dorsum emissions showed an occasional lack of coherence.
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Authors: Kee Ryeon Kang
Abstract: Deoxyhypusine synthase (DHS) catalyzes the first step in the posttranslational synthesis of hypusine in the eukaryotic initiation factor 5A (eIF5A) precursor protein. As such, the phosphorylation of DHS by the protein kinase CK2 was investigated to define the role of DHS in the regulation of eIF5A in cells. The results showed that DHS was phosphorylated by CK2 in vivo as well as in vitro. The endogenous CK2 in HeLa cells and cell lysates was able to phosphorylate DHS and this modification was enhanced or decreased by the addition of CK2 effectors, such as polylysine, heparin, or poly (Glu, Tyr). A phosphoamino acid analysis of the enzyme revealed that the DHS was mainly phosphorylated into the Thr residue, with the remainder into the Ser residue. Therefore, it would appear that the phosphorylation of DHS was a CK2-dependent cellular event, thereby opening the path for possible regulation of the interaction with the eIF5A precursor for hypusine synthesis.
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