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        검색결과 4

        1.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Known for its effectiveness in weight loss and diabetes prevention, Gymnema sylvestre products can be found in the US, Japanese, and Indian markets. However, the recommended dosage or safety of these products has not yet been proven. Therefore, development of an analytical method for detecting the content of Gymnema sylvestre in food products is required. Accordingly, this study proposes an analysis method that can examine Gymnema sylvestre in food using LC-ESI-MS/MS and KASP (Kompetitive Allele-Specific PCR) markers. In LC-ESI-MS/MS, a simultaneous analysis method for gymnemic acid and deacylgymnemic acid was optimized using negative ionization mode, and its validation test was completed for solid and liquid samples. In addition, KASP markers were prepared by finding the specific SNP of G. sylvestre in ITS2 and matK through DNA barcodes. The two KASP markers returned positive FAM fluorescence result when combined with G. sylvestre, and this aspect was confirmed in raw G. sylvestre as well. The applicability of the method was tested on 21 different food and healthy functional products containing G. sylvestre purchased on the internet. As a result, although there was a difference in the ratios of gymnemic acid and deacylgymnemic acid in LC-ESI-MS/MS, the index component was detected in all 21 products samples. In the KASP analysis, 9 products returned positive FAM result, and the rest of the products were found to be containing G. sylvestre extract. This study is the first study to use the dual system of LC-ESI-MS/MS and KASP for the analysis of G. sylvestre. The study has confirmed that these two methods are applicable to the examine G. sylvestre content in food products.
        4,000원
        2.
        1996.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, as concern about the residual antibiotics in milk increase, the detection methods of residual antibiotics used extensevely at the present time were investigated and compared to their properties and the detection limits of variable antibiotics. At first, comparative tests of the detectable sensitivity of 4 teat organisms, B.cereus, B.subtilis, M.luteus, B. stearothermophilus C-953, were performed by disc assay. As a result, B.stearotleermoph.ilus was the most sensitive strain of all other strains and showed the detect limit of 5-50 ppb for penicillins (PCs). And also, B.subtilis was showed the more effective detection limit, 200-400 ppb, for aminoglycosides (AGs) and M.luteus was showed predominant sensitivity , 50-500 ppb for macrolides(MLs) and B.cereus was the most sensitive strain for tetracyclines (TCs) and showed the detection limit of 100-400 ppb. Therefore, each test strains were showed a different sensitivity in the detection of the different antibiotic families. When the detection limit of disc assay and other methods were compared, TTCmethod was less sensitive than other methods showing 5-50 ppb detectable lebel for PCs. Also, for the detection of other antibiotic families TTC method was showed the worst sensitivity and Delvo and Charm Farm tests were similar to the detectable properties of AGs and MLs. Although disc assay was showed the similar detection limit for PCs with Delvo and Charm Farm, it was more widely effective for the detection of kanamycin, erythromycin, chlortetracycline, doxycycline, verginiamycin and so on than Delvo or Charm Farm. CharmII test was showed the best sensitivity for the most of antibiotics except neomycin and gentamycin. But it was necessary that different tests must be performed to each antibiotic family and so it was regarded that the effectiveness of that method was low.
        4,000원
        3.
        2011.09 서비스 종료(열람 제한)
        Mesenchymal stem cells (MSC) are of great interest for cell-based therapies and tissue engineering approaches, as these cells are capable for extensive self-renewal and display a multilineage differentiation potential. Clinical application of these cells for degenerative and age-related diseases has been accumulating. However, preparation of MSC before the onset of the diseases, it needs to develop the cryopreservation method. Most cryopreservation methods include fetal bovine serum (FBS) which is essential for effective cryopreservation. Yet it should not be used clinically because of the potential risk of infection. In the present study, we investigated whether human serum albumin (HSA), human serum (HS), and knockout serum replacement (KSR) can be used as an alternative of FBS for cryopreservation of human adipose derived stem cells (hADSC). Cells cryopreserved with 9% HSA showed much higher viability after thawing compared with cells frozen with 5% or 1% HSA. Cells cryopreserved with 90% HS or KSR exhibited greater viability than cells frozen with 25% and 5% HS or KSR, respectively. Viability of cells frozen with 9% HSA, 90% HS or 90% KSR was comparable to that with 90% FBS. Morphology and proliferation ability of these cells were not affected by cryopreservation when compared the freshly obtained cells. Cryopreserved hADSC expressed transcription factor genes including Oct3/4, Nanog, Nestin and Sox2, which are related to the self-renewal of stem cells. Flow cytometric analyses showed that both fresh and cryopreserved hADSC were positive for the antigens of HLA-ABC, CD44, CD73, CD90, and CD105, CD166, and negative for HLA-DR, CD31, and CD34. Similar to fresh cells, cryopreserved hADSC could differentiate into mesodermal lineages, adipogenic, osteogenic, or chondrogenic cells. These results suggest that 9% HSA, 90% HS or 90% KSR can be used to replace FBS during successful cryopreservation of hADSC.
        4.
        2011.09 서비스 종료(열람 제한)
        The human eyelid adipose-derived stem cells (HEACs) are known as a candidate source for stem cell-based therapy. HEACs possess the ability to proliferate in vitro and multipotency to differentiate into adipogenic, osteogenic and chondrogenic cells. To be used later than the time of collection, a long-term storage is needed. In this study, we investigated stem cell characteristics after cryopreservation of HEACs for 6 months and 1 year in liquid nitrogen. Frozen-thawed stem cells have shown that cumulative cell and doubling numbers were similar to those of fresh HEACs. After thawing, HEACs expressed stem cell-related genes of SCF, NANOG, OCT4, and TERT, ectoderm-related genes of NCAM and FGF5, mesoderm/endoderm-related genes of CK18 and VIM. They also consistently expressed transcripts of the immune-related genes of HLA-ABC and β2M. To induce mesodermal differentiation, cell were cultivated in adipogenic, osteogenic or chondrogenic medium for 2~3 weeks. After each differentiation culture, HEACs expressed adipocyte-, osteocyte- and chondrocytespecific genes. They were also stained with Oil red O, von Kossa, or alcian blue, revealing adipogenic, osteogenic, or chondrogenic character, respectively. The results suggest that long-term storage up to 1 year do not affect their biological properties, HEACs may be suitable for clinical application on cell-based therapies.