• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.10a
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• pp.179-179
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• 2003

• Biomedical Science Letters
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• v.10 no.2
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• pp.75-84
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• 2004

Massive identification of differentially expressed patterns has been used as a tool to detect genes that are involved in disease related process. We employed circular single stranded sense molecules as probe DNA for a DNA chip. The circular single stranded DNAs derived from 1,152 unigene cDNA clones were purified in a high throughput mode from the culture supernatant of bacterial transformants containing recombinant phagemids and arrayed onto silanized slide glasses. The DNA chip was examined for its utility in detection of differential expression profile by using cDNA hybridization. Hybridization of the single stranded probe DNA were performed with Cy3- or Cy5-labeled target cDNA preparations at $60^\circ$C. Dot scanning performed with the hybridized slide showed 29 up-regulated and 6 down-regulated genes in a cancerous liver tissue when compared to those of adjacent noncancerous liver tissue. These results indicate that the circular single stranded sense molecules can be employed as probe DNA of arrays in order to obtain a precious panel of differentially expressed genes.

• Biomolecules & Therapeutics
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• v.18 no.4
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• pp.411-419
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• 2010

Korean mistletoe has a variety of biological effects, such as immunoadjuvant activities. This study investigates the effects of Korean mistletoe lectin (Viscum album L. var. coloratum agglutinin, VCA) on human T lymphocytes to determine whether VCA acts as an immunomodulator. Purified human T-lymphocytes were cultured with VCA and RNA from each point was analyzed using Affymetrix human genome chips containing 22,500 probe sets which represents more than 18,000 transcripts derived from 14,500 human genes. As a result, there was a striking upregulation of genes coding for chemokines. Seventeen genes out of 50 coding for proteins with chemokine activity were upregulated including CXCL9 and IL-8 which are related to the treatment of cancer. In addition, 28 cytokine genes were upregulated including IL-1, IL-6, IL-8, IFN-$\gamma$, and TNF-$\alpha$. Taken together, the data suggest that Korean mistletoe lectin, in parallel with European mistletoe, has an ability to modulate human T cell function.

• Current Optics and Photonics
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• v.1 no.6
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• pp.649-654
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• 2017

In this communication, we present an expression to determine thermal lensing in isotropic materials. The heat equation is analytically solved when a Gaussian spatial laser beam profile is introduced to a cylindrical geometry of optics using a complete set of Bessel functions. This expression permits explicit calculation of variation of focal length induced by thermal lensing and allows thermal effects for various material parameters on the optics. We applied our model to a high absorption material (Ti:sapphire) and also transparent material (thallium garnet or TGG) and found that the thermal lensing can be reduced more than 4 times by adjusting the laser beam waist and optics dimensions. Our analysis is completely general and applicable to any optical system.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.5
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• pp.1330-1334
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• 2003

Astragali Radix(AR), one of the strong tonic herbs, is known to improve immunological responses in mice and human. In this study, AR's ai-reinforcing effect was examined in the context of CD4/sup +/ T cells' TCR/CD3 induced activation responses. In order to evaluate the direct effect of AR on helper T cells, CD4/sup +/ T cells are isolated using magnetic bead and their proliferation and CD69 expression in AR treated medium were assessed with anti-CD3/anti-CD28 activation for 48h. CD4 T cells' proliferation was slightly increased but there was little effect on CD69 expression. RT PCR and ELISA equally demonstrated that IL-2 and IL-4 production was increased but IFN-ν was down-regulated. This shows AR ethanol extract favors Th2 cytokine profile under neutral conditions.

• Genomics & Informatics
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• v.5 no.1
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• pp.32-35
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• 2007

Telomerase reverse transcriptase (TERT) is an enzymatic ribonucleoprotein that prolongs the replicative life span of cells by maintaining protective structures at the ends of eukaryotic chromosomes. Telomerase activity is highly up-regulated in 85-90% of human cancers, and is predominately regulated by hTERT expression. In contrast, most normal somatic tissues in humans express low or undetectable levels of telomerase activity. This expression profile identifies TERT as a potential anticancer target. By using an RNA mapping strategy based on a trans-splicing ribozyme library, we identified the regions of mouse TERT (mTERT) RNA that were accessible to ribozymes. We found that particularly accessible sites were present downstream of the AUG start codon. This mTERTspecific ribozyme will be useful for validation of the RNA replacement as cancer gene therapy approach in mouse model with syngeneic tumors.

• Genomics & Informatics
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• v.3 no.3
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• pp.63-67
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• 2005

Adaptive responses to diverse microbial pathogens might be limited in relatively few types. Host cell responses to pathogens are believed to be patterned or stereotyped along with species or class. We tried to compose the host response to Mycoplasma in terms of cellular gene expression. Although gene expression profile of two host HeLa and 293 cells were quite different each other, 30 genes were differentially expressed by mycoplasma infection in both of HeLa and 293 cells. Six of them (PR48, MADH4, MKPX, CRK, RBM7, NEK3) were related to cell cycle or proliferation. Another category of genes like IL1 HY1, KLRF1, TNFSF14, GBP1 were host defense to elicit immune responses. With this set of genes, we establish the prediction model for mycoplasma contamination.

• Journal of Information Processing Systems
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• v.19 no.5
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• pp.652-662
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• 2023

Identifying highly discriminating genes is a critical step in tumor recognition tasks based on microarray gene expression profile data and machine learning. Gene selection based on tree models has been the subject of several studies. However, these methods are based on a single-tree model, often not robust to ultra-highdimensional microarray datasets, resulting in the loss of useful information and unsatisfactory classification accuracy. Motivated by the limitations of single-tree-based gene selection, in this study, ensemble gene selection methods based on multiple-tree models were studied to improve the classification performance of tumor identification. Specifically, we selected the three most representative tree models: ID3, random forest, and gradient boosting decision tree. Each tree model selects top-n genes from the microarray dataset based on its intrinsic mechanism. Subsequently, three ensemble gene selection methods were investigated, namely multipletree model intersection, multiple-tree module union, and multiple-tree module cross-union, were investigated. Experimental results on five benchmark public microarray gene expression datasets proved that the multiple tree module union is significantly superior to gene selection based on a single tree model and other competitive gene selection methods in classification accuracy.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.600-603
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• 2000

DNA chip containing 207 E. coli genes related to important metabolisms such as (TCA cycle, glycolysis, fermentation and etc) were used to carry out a comprehensive investigation of the change in metabolism and physiology during high cell density culture of E. coli by fed-batch cultivation.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.390.4-391
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• 2001