• Proceedings of the KSAR Conference
• /
• 2000.10a
• /
• pp.10-12
• /
• 2000

Members of the glycoprotein family, which includes CG, LH, FSH and TSH, comprise two noncovalently linked $\alpha$- and $\beta$-subunits. Equine chorionic gonadotropin (eCG), known as PMSG, has a number of interesting and unique characteristics since it appears to be a single molecule that possesses both LH- and FSH-like activities in other species than the horse. This dual activity of eCG in heterologous species is of fundamental interest to the study of the structure-function relationships of gonadotropins and their receptors. CG and LH $\beta$ genes are different in primates. In horse, however, a single gene encodes both eCG and eLH $\beta$-subunits. The subunit mRNA levels seem to be independently regulated and their imbalance may account for differences in the quantities of $\alpha$ - and $\beta$ -subunits in the placenta and pituitary. The dual activities of eCG could be separated by removal of the N-linked oligosaccharide on the $\alpha$-subunit Asn 56 or CTP-associated O-linked oligosaccharides. The tethered-eCG was. efficiently secreted and showed similar LH-like activity to the dimeric eCG. Interestingly, the FSH-like activity of the tethered-eCG was increased markedly in comparison with the native and wild type eCG. These results also suggest that this molecular can implay particular models of FSH-like activity not LH-like activity in the eCG/indicate that the constructs of tethered molecule will be useful in the study of mutants that affect subunit association and/or secretion. A single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds that have only FSH-like activity. The LH/CG receptor (LH/CGR), a membrane glycoprotein that is present on testicular Leydig cells and ovarian theca, granulosa, luteal, and interstitial cells, plays a pivotal role in the regulation of gonadal development and function in males as well as in nonpregnant and pregnant females. The LH/CGR is a member of the family of G protein-coupled receptors and its structure is predicted to consist of a large extracellular domain connected to a bundle of seven membrane-spanning a-helices. The LH/CGR phosphorylation can be induced with a phorbol ester, but not with a calcium ionophore. The truncated form of LHR also was down-regulated normally in response to hCG stimulation. In contrast, the cell lines expressing LHR-t63I or LHR-628, the two phosphorylation-negative receptor mutant, showed a delay in the early phase of hCG-induced desensitization, a complete loss of PMA-induced desensitization, and an increase in the rate of hCG-induced receptor down-regulation. These results clearly show that residues 632-653 in the C-terminal tail of the LHR are involved in PMA-induced desensitization, hCG-induced desensitization, and hCG-induced down-regulation. Recently, constitutively activating mutations of the receptor have been identified that are associated with familial male-precocious puberty. Cells expressing LHR-D556Y bind hCG with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. This mutation enhances the internalization of the free and agonist-occupied receptors ~2- and ~17-fold, respectively. We conclude that the state of activation of the LHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing LHR-L435R is due to the fast rate of internalization of the bound hCG. This statement is supported by the finding that hCG responsiveness is restored when the cells are lysed and signal transduction is measured in a subcellular fraction (membranes) that cannot internalize the bound hormone.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.36 no.3
• /
• pp.175-185
• /
• 2000

This paper described on a basic study to organize fishing vessel control system in order to control efficiently fishing vessel in Korean offshore. It was digitalized ARPA image on the fishing processing of a fleet of purse seiner in conducting fishing operation at Cheju offshore in Korea as a digital camera and then simulated by used VTMS. Futhermore, it was investigated on the application of FVTMS which can control efficiently fishing vessels in fishing ground. The results obtained were as follows ; (1) It was taken 16 minutes and 35 minutes to casting and hauling net in fishing processing respectively. The length of rope pulled by scout boat was 200m, tactical diameter in casting net was 340.8m, turning speed was 6kts as well. (2) The processing of casting and hauling net was moved to SW, NE as results of simulation when the current direction and speed set into NE, 2kts and SW, 2kts respectively. Such as these results suggest that can predict to control the fishing vessel previously with information of fishing ground, fishery and ship's maneuvering, etc. (3) The control range of VTMS radar used in simulation was about 16 miles. Although converting from a radar of the control vessel to another one, it was continuously acquired for the vector and the target data. The optimum control position could be determined by measuring and analyzing to distance and direction between the control vessel and the fleet of fishing vessel. (4) The FVTMS(fishing vessel traffic management services) model was suggested that fishing vessels received fishing conditions and safety navigation information can operate safely and efficiently.

• Korean Journal of Microbiology
• /
• v.46 no.1
• /
• pp.15-20
• /
• 2010

Xenotransplantation of pig organs is complicated by the existence of polytropic replication-competent porcine endogenous retroviruses (PERV) capable of infecting human cells. Two classes of infectious human-tropic replication-competent PERVs (PERV-A and PERV-B) and one class of ecotropic PERV-C are known. The potential for recombination between ecotropic PERV-C and human-tropic PERVs adds another level of infectious risk. A recombinant PERV-A/C (PERV-A14/220) virus is 500-fold more infectious than PERV-A. Two determinants of this high infectivity was identified; one was isoleucine-to-valine substitution at position 140 in RBD (receptor binding domain), and the other lies within the PRR (proline rich region) of the envelope protein. To examine whether the effects of the cytoplasmic tail of the PERV-C Env on fusogenesity also influences infectivity, we constructed a pseudotype retroviral vectors containing MoMLV core protein and PERV envelopes. Pseudotyping experiments with the PERV envelope glycoproteins indicated that recombinant PERV-A/C virus is 10-fold more infectious than PERV-A by lacZ staining. This result supports the suggestion that viral transduction of PERV-A/C is enhanced by a membrane-proximal cytoplasmic amphiphilic ${\alpha}$-helix in PERV-C Env tail.

• 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.

• Journal of Chest Surgery
• /
• v.31 no.12
• /
• pp.1134-1146
• /
• 1998

Background: The tumor suppressor gene p53 is one of the most frequently altered genes in human tumors, including those of the lung. There is now a compelling evidence that wild-type p53 can negatively influence cell growth by causing G1 arrest or by inducing apoptosis. The possibilities of using p53 for gene therapy are also gathering much interest. Material and Method: Our approach towards understanding p53 function would be to study the biological consequences of overexpression of wild-type p53 in normal and tumor cells by using adenovirus vectors capable of giving high levels of the p53 gene product in cells. We have used this vector containing wild-type p53 to infect tumor cells with different p53 status (null, mutant, or wild-type) to confirm that expression of p53 in null or mutant cell lines becomes possible by Adenovirus-p53 transduction, to examine the effects of high levels of p53 expression on the growth properties of tumor cells, to evaluate the role of apoptosis in p53-mediated biological effects, and to examine the effect of Adenovirus-p53 on the tumorigenicities of the lung cancer cell lines in vitro. Result: The results of our study showed that cells expressing endogenous mutant p53 and those devoid of p53 expression altogether were significantly more sensitive to Adenovirus-p53-mediated cytotoxicity compared to tumor cells expressing endogenous wild-type p53 and that overexpression of wild-type p53 induced programmed cell death. Also we knew that Adenovirus-p53 significantly reduced tumor colony formation of human non-small cell lung cancer cell lines, and decreased the growth of pre-formed colonies in vitro. Conclusion: These results suggest that adenovirus is an efficient vector for mediating transfer and expression of tumor suppressor genes in human non-small cell lung cancer cells and that the tumor cells null for p53 or expressing mutant p53 readily undergo apoptosis by Adenovirus-p53.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.23 no.4
• /
• pp.295-305
• /
• 2001

Protein kinase C (PKC) is known to play a pivotal role in neoplastic transformation cells and its high expression is often found in a variety of types of tumors including oral cancer. While PKC is associated with the altered signal transduction pathway of the tumor cells, it is still unclear which isoform is involved in the carcinogenesis process. Since the cellular distributions and the roles of PKC are isoform-specific, it is very important to identify the specific target molecules to improve our understanding of the carcinogenesis processes. Thus, the present study attempted to perform chemical carcinogen-induced neoplastic transformation of human epithelial cells and analyze the specific isoform of PKCs involved in the cellular transformation. The study analyzed overall PKC responses upon MNNG(N-Methyl-N'-nitro-N-nitroso guanidine) exposure with [$^3H$] PDBu binding assay. PKC translocation was observed at high doses of MNNG treatment in the presence of extracellular calcium. Such effects were not observed in the absence of extracellular calcium. Translocational effects with exposure of MNNG was further enhanced in the presence of hydrocortisone. The result suggests that the type of PKC involved may be $Ca^{2+}$-dependent classical isoform and steroid hormone enhances PKC activation. Among cPKC isoforms examined, only $PKC-{\alpha}$ and r showed significant translocation of protein levels from cytosolic fraction to membrane fraction, as analyzed by immunoblot. $PKC-{\varepsilon}$ in nPKC class showed an inch·eased translocation, but other forms in this class did not show the effect. None of isoforms in aPKC class was affected by MNNG treatment. The study demonstrated that there was a certain specificity in the patterns of isoform induction follwong chemical carcinogen exposure and helped identify all the types of PKC isoforms expressed in human epithelial cells. It was revealed that PKC isoforms were activated in an early resonse to chemical carcinogen, suggesting that PKC be associated with carcinogenesis process from an early stage in this particular cell system. The study will contribute to improving our understanding of chemical-induced carcinogenesis in human cells and may provide a scientific basis to introduce the specific PKC inhibitors as an anticancer drug of epithelial cell-origin cancers including oral cancer.

• Trans-
• /
• v.7
• /
• pp.19-48
• /
• 2019

This study was described to examine the meaning of the media exhibition work <70mK>, which aims to capture the topography of the collective consciousness of the Korean people through large-scale interviews. <70mK> edits and organizes interview images of individual beings in mosaic-like layouts and forms, creating video exhibitions and holding exhibitions. The objects in the split frame show the continuity of differences that reveal their own thoughts and personalities. This is a synchronic and conscious collective typology in which the intrinsic nature of the individuals is embodied in a simultaneous and holistic image. Interview images reveal their own form as a actual being and convey the intrinsic nature of one's own as oral information. <70mK> constructs a new individualization by aesthetically structuring the forms and information of life individuals in the extension of a specific group. The beings in the frame are not communicating with each other and are looking straight ahead. it conveys to visitors their relationship and personality as the preindividual reality. It is the repetitive arrangement and composition of heterogeneity and difference that each individual shows, and is a chain operation that includes collective identity behind it. <70mK> constructs the direct images and sounds of individual interviewee, creating a new form of information transfer called Video Art Exhibition. This makes metaphors and perceptions of the meaning and process of transindividual relationships and the meaning of psychic individuation and collective individuation. This is an appropriate case to explain with modern technology and individualization of Gilbert Simondon thought together with the meaning of becoming and relation of individualization. The exhibition space constructed by <70mK> is an aesthetic methodology of the psychic and collective meaning and its relationship to a particular group of individuals through which they are connected. Simondon studied the meaning of the process of individualization and the meaning of becoming, and is a philosopher who positively considered the potential of modern technology. <70mK> is a new individual as structured and generated ethical reality mediated by modern technology mechanisms and network behaviors. It is an case of an aesthetic and practical methodology of how interviews function as 'transduction' in the process of individualization in which technology is cooperated. The direct images and sounds of <70mK> are systems in which the information of life individuals is carried, amplified, accumulated and transmitted. It is also a new individual as a psychic and collective landscape. It is a newly became exhibition art work through the multiple individualization, and is a representation of transindividual meanings and process. The media exhibition art of individualized metastable states leads to new relationships in which viewers perceive the same preindividual reality and feel affectivity. The exhibition space of <70mK> becomes a stage for preparing the actual possibility of the transindividual group beyond the representation of the semantic function.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.32 no.3
• /
• pp.218-228
• /
• 2010

Components of dental resin-based restorative materials are reported to leach from the filling materials even after polymerization. Hydroquinone (HQ) is one of the major monomers used in the dental resin and is known as a carcinogen. Thus, carcinogenic risk of HQ leaching from the dental resin becomes a public health concern. The present study attempted to examine the carcinogenic potentials of HQ on the human epithelial cell, which is the target cell origin of the most of oral cancers. Cytotoxicity of HQ was observed above 50${\mu}M$ as measured by LDH assay, indicating a relatively low toxicity of this substance in human epithelial cells. The parameters of neoplastic cellular transformation such as cell saturation density, soft agar colony formation and cell aggregation were analyzed to examine the carcinogenic potential of HQ. The study showed that 2-week exposure of HQ showed the tendency of increase in the saturation density and the significant enhancement of soft agar colony formation at the highest dose, 50 ${\mu}M$ only. It is suggested that HQ has a weak potential of carcinogenicity. When cells were treated with HQ and TPA, a well-known tumor promoter, the parameters of neoplastic cellular transformation was significantly increased. This result indicates that the potential risk of carcinogenicity from HQ is largely dependent upon the presence of promoter. Exposure of 50 ${\mu}M$ HQ increased the time-dependent apoptosis as measured by the ELISA kit. This concentration coincides with a dose of neoplastic transformation, indicating a possible link between apoptosis and HQ-induced cellular transformation. Hydroquinone generated Reactive Oxygen Species (ROS) which was evidenced by the treatment of antioxidants such as trolox and N-acetyl cysteine and the GSH depleting agent, BSO. Antioxidants blocked the generation of ROS and the GSH depleting agent, BSO dramatically increased the ROS production. Since HQ is known to increase ROS production thru activation of transcriptional factor such as c-Myb and Pim-1, it is speculated that ROS generation by HQ plays a role in the activation of oncogene, which may lead to neoplastic transformation. In addition, ROS is involved in the alteration of signal transduction, which regulates the apoptosis in many cellular systems. Thus, ROS-mediated apoptosis may be involved in the HQ-induced carcinogenic processes. Protein kinase C (PKC) is known to play pivotal roles in neoplastic transformation of cells and its high expression is often found in a variety of types of tumors including oral cancer. PKC translocation of PKC-${\alpha}$ was observed following HQ exposure. Altered signaling system may also play a role in the transformation process. Taken together, HQ leached from the dental resin does not pose a significant threat as a cancer causing agent, but its carcinogenic potential can be significantly elevated in the presence of promoter. The mechanism of HQ-induced carcinogenesis involved ROS generation, apoptosis and altered signaling pathway. The present study will provide a valuable data to estimate the potential risk of HQ as a carcinogen and understand mechanism of HQ-induced carcinogenesis in human epithelial cells.

• Tuberculosis and Respiratory Diseases
• /
• v.46 no.2
• /
• pp.229-240
• /
• 1999

Background: The impact of the immune response on cancer gene therapy using viral vectors to deliver a "suicide gene" is currently unclear. A vigrous immune response targeted at viral proteins or transgene may enhance the efficacy of tumor destruction and even augment responses to tumor antigens. These responses may involve the release of cytokines and stimulation of tumor specific cytotoxic T-lymphocytes that enhance therapeutic efficacy. On the other hand, a vigorous rapid cellular immune response may destroy cells expressing the therapeutic gene and attenuate the response to therapy. Furthermore, development of neutralizing antibody responses may prevent readministration of virus, a potentially significant limitation. Evaluating the significance of these limitations in animal models and developing solutions are therefore of obvious importance. Methods: After retroviral transduction of mouse mesothelioma cell line(AB12) with Herpes Simplex Virus thymidine kinase (HSVtk) gene in vitro, subcutaneous flank tumors were established. To study the effect of intact immune system on efficacy of tumor erradication, the ability of the HSVtk/ganciclovir system to inhibit tumor growth was compared among normal Balb/c mice, immunodeficient Balb/c-nude and SCID mice, and Balb/c mice immunosuppressed with cyclosporin. Results: Ganciclovir treatment resulted in greater inhibition of tumor growth in Balb/c mice compared with immunodeficient Balb/c-nude mice and SCID mice(in immunodeficient mice, there were no growth inhibition by ganciclovir treatment). Ganciclovir treatment resulted in greater inhibition of tumor growth in noncyclosporin (CSA) treated Balb/c mice compared with CSA treated Balb/c mice. On day 8, mean ganciclovir-treated tumor volume were 65% of control tumor volume in Balb/c mice versus 77% control tumor volume in CSA-treated Balb/c mice. This effect was still evident during therapy (day 11 and 13). On day 13, non-CSA treated tumor volume was 35% of control tumor volume versus 60% of control tumor volume in CSA treated Balb/c mice. Duration of expression of HSVtk was not affected by the immunosuppression with CSA. Conclusion: These results indicate that the immune responses against retrovirally transduced cells enhance the efficacy of the HSVtk/ganciclovir system. These findings have important implications for clinical trials using currently available retrovirus vectors as well as for future vector design.

• Tuberculosis and Respiratory Diseases
• /
• v.55 no.1
• /
• pp.21-30
• /
• 2003

Background : Mucin synthesis in airways has been reported to be regulated by the epidermal growth factor receptor (EGFR) system. Epidermal growth factor receptor transactivation was identified as a critical element in G-protein-coupled receptors (GPCRs)-induced mitogenic signaling. EGF receptor transactivation by G-protein-coupled receptors requires metalloproteinase cleavage of proHB-EGF. This study was hypothesized that lipopolysaccharide (LPS)-induced mucin production associates with epidermal growth factor receptor transactivation, and MUC5AC production associates with epidermal growth factor receptor transactivation by G-protein-coupled receptors that regulates by metalloproteinase. Method : MUC5AC mucin production was examined in NCI-H292 cells and MUC5AC protein synthesis was assessed using ELISA. For the evaluation of mechanism of LPS-induced MUC5AC production, $TNF{\alpha}$ was measured using ELISA with or without pretreatment of heterotrimeric G-protein inhibitor, mastoparan. MUC5AC protein was measure with pretreatment of polyclonal $TNF{\alpha}$ antibody or mastoparan on LPS-induced MUC5AC production. For the evaluation of relation of G-protein and MUC5AC production, G-protein stimulant, mastopara-7, or matrix metalloproteinase, ADAM10, was added to NCI-H292 cells. MUC5AC protein was measure with pretreatment of polyclonal EGF antibody on mastoparan-7-induced MUC5AC production. Results : LPS alone did not increase significantly MUC5AC production. LPS with $TNF{\alpha}$ induced dose-dependently MUC5AC production in NCI-H292 cells. LPS increased dose-dependently $TNF{\alpha}$ secretion, which was inhibited by mastoparan. LPS with $TNF{\alpha}$-induced MUC5AC production was inhibited by neutralizing polyclonal $TNF{\alpha}$ antibody, mastoparan or AG 1472. Mastoparan-7 or ADAM10 increased dose-dependently MUC5AC production, which was inhibited by polyclonal neutralizing EGF antibody. Conclusion : In LPS-induced MUC5AC synthesis, LPS causes $TNF{\alpha}$ secretion, which induces EGFR expression. EGFR tyrosine kinase phosphorylation result in MUC5AC production. EGF-R transactivation by G-protein-coupled receptors requires matrix metalloproteinase cleavage of proHB-EGF.