• Journal of Korean Neurosurgical Society
• /
• v.30 no.3
• /
• pp.263-271
• /
• 2001

Objective : Glioblastomas, the most common type of primary brain tumors, are highly invasive and cause massive tissue destruction at both the tumor invading edges and in areas that are not in direct contact with glioma cells. As a result, patients with high-grade gliomas are faced with a poor prognosis. Such grim statistics emphasize the need to better understand the mechanisms that underlie glioma invasion, as these may lead to the identification of novel targets in the therapy of high grade gliomas. Protein kinase C(PKC) is a family of serine/threonine kinases and an important signal transduction enzyme that conveys signals generated by ligand-receptor interaction at the cell surface to the nucleus. PKC appears to be critical in regulating many aspects of glioma biology. The purpose of this study was to assess accurately the role of PKC in the invasion regulation of human gliomas based on hypothesis that protein kinase C(PKC) is functional in the process of glial tumor cell invasion. Method : To test this hypothesis, U-87 malignant glioma cell line intracellular PKC levels were up and down regulated and their invasiveness was tested. Intracellular PKC level was characterized using PKC activity assays. Invasion assays including barrier migration and spheroid confrontation were used to study the relationship between PKC concentration and invasiveness. Result : The cell line which were treated by PKC inhibitor tamoxifen and hypericin exhibited decreased PKC activity and decreased invasive abilities dose dependently both in matrigel invasion assay and tumor spheroid fetal rat brain aggregates(FRBA) confrontation assay. However, the cell line that was treated by PKC activator 12-O-tetradecanylphorbol-13acetate(TPA) did not exhibit increases in either PKC activity or invasive ability. Conclusion : These studies suggest that PKC may be a useful molecular target for the chemotherapy of glioblastoma and other malignancies and that a therapeutic approach based on the ability of PKC inhibitors may be helpful in preventing invasion.

• Nuclear Medicine and Molecular Imaging
• /
• v.41 no.5
• /
• pp.359-363
• /
• 2007

Purpose: Incidental parotid lesions on F-18 FDG-PET can mimic distant metastasis of underlying malignancy. The prevalence and the clinico-pathologic findings of PET positive parotid lesions have not been known. We investigated how often incidental parotid lesions are found on clinical FDG-PET studies and what the clinico-pathologic characteristics of those parotid lesions are in the present study. Materials and Methods: We retrospectively reviewed 3,344 cases of FDG-PET which had been obtained in our hospital from May 2003 to Dec 2006. The indications of FDG-PET were: evaluation of known/suspected cancer (n= 3,212) or screening of cancer in healthy subjects (n=132). Incidental parotid lesion on FDG-PET was defined as an un-expected FDG uptake in one of parotid glands which was not primary target lesion of current FDG-PET. FDG uptake was represented by maximum standardized uptake value (maxSUV). Final diagnosis was made by pathologic analysis or clinical follow-up assessment. Results: Fifteen (0.45% = 15/3,344) incidental parotid lesions were found and they were all benign lesions. The maxSUV ranged from 1.7 to 8.6 (mean${\pm}$s.d. = $3.7{\pm}1.9$). Final diagnoses of the incidental parotid lesions were; Warthin's tumor (n=2), pleomorphic adenoma (n=1), other un-specified benign lesion (n=1), and benign lesions under bases of imaging studies (n=3) and of clinical follow-up (n=8). Conclusion: All of incidentally found parotid lesions in clinical FDG-PET studies were confirmed as benign lesions with prevalence of 0.45%. Close follow up using PET or CT might be a reasonable approach for determining the nature of incidentally found parotid lesions.

• Journal of Life Science
• /
• v.23 no.5
• /
• pp.689-697
• /
• 2013

In the United States, about 40,000 new cases of oral cancer are diagnosed each year and nearly 7,800 patients died from it in 2012. Omega-3 polyunsaturated fatty acids have been found to have anticancer effects in a variety of cancer cell lines and animal models, but their effect in oral cancer remains unclear. This study was designed to examine the effect of docosahexaenoic acid (DHA, a kind of omega-3 fatty acid) on oral cancer cells and the molecular mechanism of its action. We found that exposure of squamous cell carcinoma-4 (SCC-4) and squamous cell carcinoma-9 (SCC-9) human oral cancer cells to DHA induced growth inhibition in a dose- and time-dependent manner. Meanwhile, in addition to the elevated levels of apoptotic markers, such as cleaved PARP, subG1 portion and TUNEL-positive nuclei, DHA led to autophagic vesicle formation and an increase in autophagic flux, indicating the involvement of both apoptosis and autophagy in the inhibitory effects of DHA on oral cancer cells. Further experiments revealed that the apoptosis and autophagy induced by DHA were linked to inhibition of mammalian target of rapamycin (mTOR) signaling by AKT inhibition and AMP-activated protein kinase (AMPK) activation in SCC-9 cells. Together, our results suggest that DHA induces apoptosis- and autophagy-associated cell death through the AMPK/AKT/mTOR signaling pathway in oral cancer cells. Thus, utilization of omega-3 fatty acids may represent a promising therapeutic approach for chemoprevention and treatment of human oral cancer.

• Korean Journal of Veterinary Research
• /
• v.25 no.1
• /
• pp.7-17
• /
• 1985

Many investigators have been pursuing various attempts so far to produce hepatitis B surface antigen(HBsAg) vaccines using the techniques such as isolation from plasma of chronic HBsAg carrier, recombinant DNA technique or preparation of synthetic peptides specific for immunogenic determinants. Hepatitis B virus can not grow on any cell lines by the tissue culture technique at the present time. The plasma of chronic HBsAg carrier is expensive and its source is limited. The HBsAg from the recombinant DNA technique gave still very low yield. Another approach, therefore, has been initiated to develop a synthetic hepatitis B virus vaccine. The possible use of several distinct synthetic vaccines in prophylaxis can be facilitated by availability of full synthetic immunogens. Peptides synthesized for potential application as antiviral vaccines have been mostly tested in the form of conjugates with carrier proteins, although the free synthetic peptide can be immunogenic. To understand basic knowledges on the antigenicity and immunogenicity of a synthetic peptide specific for major immunogenic determinant of HBsAg, a nonapeptide, $H_2N^{139}Cys-Thr-Lys-Pro-Thr-Asp-Gly-^{146}Asn-Aba$ COOH, which corresponds to HBsAg amino acid residues 139 to 147, was synthesized by the Merrifield's solid-phase method with a slight modification. The antigenicity and immunogenicity of this specific synthetic peptide were examined comparing with purified plasma-derived natural HBsAg. The results obtained are as follows; 1. The peptide synthesized showed the identical amino acid composition to the theoretical value. The degree of purification and molecular weight were acertained by methods of high performance liquid chromatography and mass spectrometry. 2. Using m-maleimidobenzoyl-N-hydroxysuccinimide ester as a conjugating agent, the synthetic peptide was conjugated to rabbit albumin and ${\gamma}$-globulin, tetanus and diphtheria toxoids, and keyhole limpet hemocyanin. Their conjugation yields were 8.3, 9.5, 15.8, 13.5, and 11.2%, respectively. 3. The natural HBsAg was purified from plasma of chronic HBsAg carrier. By the electron microscopic observation of the purified natural HBsAg preparation, no Dane particles were observed and the preparation showed negative DNA polymerase activity. 4. Antigenicity of the synthetic peptide and the plasma-derived natural HBsAg was determined by competition radioimmunoassay using $^{125}I$-natural HBsAg. Their 50% inhibitions appeared as $90{\mu}g/ml$ and $0.12{\mu}g/ml$ for the synthetic peptide and the natural HBsAg, respectively. This indicates that the former was about 750-fold less antigenic than the latter. 5. Immunogenicity of the synthetic peptide was determined by administering the peptide-carrier conjugates into rabbits with and without Freund's complete adjuvant. Regardless the carrier proteins and adjuvant, positive immune responses to the synthetic peptide were observed. The higher antibody titers, however, were shown in the groups administered with Freund's complete adjuvant. 6. Immunizing dose 50% in mice of the various peptide-carrier conjugates was 5.47, 6.00, 65.16, 31.25 and $13.03{\mu}g/dose$ for rabbit albumin and ${\gamma}$-globulin, tetanus and diphtheria toxoids, and keyhole limpet hemocyanin, respectively, while the natural HBsAg showed $0.65{\mu}g/dose$. 7. It was postulated that homologous proteins prefer to heterologous ones as the carriers.

• Journal of Plant Biotechnology
• /
• v.46 no.3
• /
• pp.165-171
• /
• 2019

Marker-assisted backcrossing (MABC) is useful for selecting an offspring with a highly recovered genetic background for a recurrent parent at early generation to various crops. Moreover, marker-assisted backcrossing (MABC) along with marker-assisted selection (MAS) contributes immensely to overcome the main limitation of the conventional breeding and it accelerates recurrent parent genome (RPG) recovery. In this study, we were employed to incorporate rin gene(s) from the donor parent T13-1084, into the genetic background of HK13-1151, a popular high-yielding tomato elite inbred line that is a pink color fruit, in order to develop a rin HK13-1084 improved line. The recurrent parent genome recovery was analyzed in early generations of backcrossing using SNP markers obtained from genotyping-by-sequencing analysis. From the $BC_1F_1$ and $BC_2F_1$ plants, 3,086 and 4868 polymorphic SNP markers were obtained via GBS analysis, respectively. These markers were present in all twelve chromosomes. The background analysis revealed that the extent of RPG recovery ranged from 56.7% to 84.5% and from 87.8% to 97.8% in $BC_1F_1$ and $BC_2F_1$ generations, respectively. In this study, No 5-1 with 97.8% RPG recovery rate among $BC_2F_1$ plants was similar to HK13-1151 strain in the fruit shape. Therefore, the selected plants were fixed in $BC_2F_2$ generation through selfing. MAS allowed identification of the plants that are more similar to the recurrent parent for the loci evaluated in the backcross generations. MABC can greatly reduce breeding time as compared to the conventional backcross breeding. For instance, MABC approach greatly shortened breeding time in tomato.

• Journal of the Korean Applied Science and Technology
• /
• v.40 no.2
• /
• pp.223-232
• /
• 2023

Oxidative stress plays a significant role in the pathogenesis of various skin conditions, resulting in cellular and tissue damage that can contribute to the development of skin tone unevenness, roughness and wrinkles. In this study, we found that Trifolium pratense L. extract (TE) attenuated oxidative-induced damage in HaCaT cells and elucidated the underlying molecular mechanism. Our finding demonstrated that TE effectively protected HaCaT cells against H₂O₂-induced cell death by inhibiting caspase-3 activation, downregulating Bax and upregulating Bcl-2, and attenuating the activation of three mitogen-activated protein kinases (MAPKs). Our results suggest that TE has remarkable cytoprotective properties against oxidative damage in HaCaT cells and could serve as a complementary or alternative approach to prevent and treat skin damage.

• Nuclear Medicine and Molecular Imaging
• /
• v.41 no.3
• /
• pp.234-240
• /
• 2007

Purpose: In this study we propose a block-iterative method for reconstructing Compton scattered data. This study shows that the well-known expectation maximization (EM) approach along with its accelerated version based on the ordered subsets principle can be applied to the problem of image reconstruction for Compton camera. This study also compares several methods of constructing subsets for optimal performance of our algorithms. Materials and Methods: Three reconstruction algorithms were implemented; simple backprojection (SBP), EM, and ordered subset EM (OSEM). For OSEM, the projection data were grouped into subsets in a predefined order. Three different schemes for choosing nonoverlapping subsets were considered; scatter angle-based subsets, detector position-based subsets, and both scatter angle- and detector position-based subsets. EM and OSEM with 16 subsets were performed with 64 and 4 iterations, respectively. The performance of each algorithm was evaluated in terms of computation time and normalized mean-squared error. Results: Both EM and OSEM clearly outperformed SBP in all aspects of accuracy. The OSEM with 16 subsets and 4 iterations, which is equivalent to the standard EM with 64 iterations, was approximately 14 times faster in computation time than the standard EM. In OSEM, all of the three schemes for choosing subsets yielded similar results in computation time as well as normalized mean-squared error. Conclusion: Our results show that the OSEM algorithm, which have proven useful in emission tomography, can also be applied to the problem of image reconstruction for Compton camera. With properly chosen subset construction methods and moderate numbers of subsets, our OSEM algorithm significantly improves the computational efficiency while keeping the original quality of the standard EM reconstruction. The OSEM algorithm with scatter angle- and detector position-based subsets is most available.