Effects of High Glucose and Advanced Glycosylation Endproducts(AGE) on the in vitro Permeability Model (당과 후기당화합물의 생체 외 사구체여과율 모델에 대한 역할)
-
- Childhood Kidney Diseases
- /
- v.10 no.1
- /
- pp.8-17
- /
- 2006
Purpose : We describe the changes of rat glomerular epithelial cells when exposed to high levels of glucose and advanced glycosylation endproducts(AGE) in the in vitro diabetic condition. We expect morphological alteration of glomerular epithelial cells and permeability changes experimentally and we may correlate the results with a mechanism of proteinuria in DM. Methods : We made 0.2 M glucose-6-phsphate solution mixed with PBS(pH 7.4) containing 50 mg/mL BSA and pretense inhibitor for preparation of AGE. As control, we used BSA. We manufactured and symbolized five culture dishes as follows; B5 - normal glucose(5 mM) + BSA, B30 - high glucose(30 mM) + BSA, A5 - normal glucose(5 mM) + AGE, A30 - high glucose(30 mM) + AGE, A/B 25 - normal glucose(5 mM) + 25 mM of mannitol(osmotic control). After the incubation period of both two days and seven days, we measured the amount of heparan sulfate proteoglycan(HSPG) in each dish by ELISA and compared them with the B5 dish at 2nd and 7th incubation days. We observed the morphological changes of epithelial cells in each culture dish using scanning electron microscopy(SEM). We tried the permeability assay of glomerular epithelial cells using cellulose semi-permeable membrane measuring the amount of filtered BSA through the apical chamber for 2 hours by sandwich ELISA. Results : On the 2nd incubation day, there was no significant difference in the amount of HSPG between the 5 culture dishes. But on the 7th incubation day, the amount of HSPG increased by 10% compared with the B5 dish on the 2nd day except the A30 dish(P<0.05). Compared with the B5 dish on the 7th day the amount of HSPG in A30 and B30 dish decreased to 77.8% and 95.3% of baseline, respectively(P>0.05). In the osmotic control group (A/B 25) no significant correlation was observed. On the SEM, we could see the separated intercellular junction and fused microvilli of glomerular epithelial cells in the culture dishes where AGE was added. The permeability of BSA increased by 19% only in the A30 dish on the 7th day compared with B5 dish on the 7th day in the permeability assay(P<0.05). Conclusion: We observed not only the role of a high level of glucose and AGE in decreasing the production of HSPG of glomerular epithelial cells in vitro, but also their additive effect. However, the role of AGE is greater than that of glucose. These results seems to correlate with the defects in charge selective barrier. Morphological changes of the disruption of intercellular junction and fused microvilli of glomerular epithelial cells seem to correlate with the defects in size-selective barrier. Therefore, we can explain the increased permeability of glomerular epithelial units in the in vitro diabetic condition.
Jangkei(狀啓) made to the Royal Court by Yi Sun-sin during the Japanese invasions of Korea is handed down under the names of Jangcho(狀草), Keicho(啓草), Keibon(啓本) and others depending on copying patterns of those times and later times as it was copied out by a third person. In particular, "YimjinJangcho(壬辰狀草)" which Yi drew up during his service as the director of the naval forces in Jeolla Jwasooyeong is known as the most popular Jangkei. "ChungMinKongKeicho" which has been re-located recently after loss is a national treasure level cultural property as valuable as "YimjinJangcho" and should be treated as a model of Yi Sun-sin's other Jangkeis by next generations. As of now, however it is not confirmed if it is a totally new book related to Yi Sun-sin or is supplementary to the lost Jangkei, this study decided to ascertain relevant information through a bibliographic discussion on the question. "Chungmin(忠愍)" was the title that was used after the death of Yi Sun-sin, and "ChungMinKongKeicho" was completed when Jangkei was copied in 1662. 12 books that would not be found in YimjinJangcho are included in the book and such books are also present in the Jangkei supplement which has been known lost so far. What should be especially focused on here is that the forms and contents of these (11) photographs that Japanese shot from "ChungMinKongKeicho" in 1928 turned out to be completely identical to those of the original copy. The point that Korean History Compilation Committee added the 12 books to Jangkei as referring to the book as "One Keicho(啓草) partially copied(抄寫) in separation" and that Cho Sung-do categorized the 12 books into a supplement and others can be solid proofs to make the Jangkei supplement called "ChungMinKongKeicho". In terms of "ChungMooKongKeicho", since it consists of 62 books in total, it is not reasonable to see the book as Jangkei supplement which has the extra 12 more books for itself. "ChungMooKongKeibon" in "ChungMooKongYusa" was written with a total of 16 books. In the body, Yidumun is only clearly present, and the three books in the later part are same with the original copy of "ChungMooKongKeicho". "YimjinJangcho" by Korean History Compilation Committee has been the only book in which Yidumun was observed so far but now, it is assumed that the publication date of "ChungMooKongKeibon" goes before that of the former. The counterargument to the opinion that "ChungMinKongKeicho" is the supplement to Jangkei is based on Lee Eun-sang's comment "One page of a log in the Jangkei copy supplement." At first Seol Ui-sik introduced a piece photo of the rough draft of "MoosulIlki" in a drawing form through "Nanjung Ilkicho by Yi Sun-sin" in 1953. Lee Eun-sang also added two pages of the handwritten Yilkicho in the Jangkeichobon supplement to "MoosulIlki" and for the second time, the phrase "One page of a log written during the last 10 days after the Jangkei copy supplement" and "Supplement" were used. Those views are originated from the comment "One photograph of the rough draft of "MoosulIlki"" which Seol Ui-sik introduced without knowledge of the exact source. Lee Eun-sang said, "One page of a log in the Jangkei copy supplement" because Lee mistook "ChungMooKongYusa" for a book related to Jangkei. Since it is the wrong argument different from the actual situation of the original copy, if it has to be corrected, it should be rephrased "One page of a log in ChungMooKongYusa." After all, the source of the counterargument is the mistake because there has never been the Jangkei supplement with one page of a log included. All the Jangkeis other than "YimjinJangcho" can be said as the Jangkei supplements but still, they are separated from the other Jangkeis for the extra 12 more books are present in the commonly-called Jangkei supplement. Due to that reason, the argument on how "ChungMinKongKeicho" with the 12 books added is the popular Jangkei supplement should be considered more reasonable.
The purpose of this research is to construct research framework for international franchising based on existing literature and to identify research components in the framework. Franchise can be defined as management styles that allow franchisee use various management assets of franchisor in order to make or sell product or service. It can be divided into product distribution franchise that is designed to sell products and business format franchise that is designed for running it as business whatever its form is. International franchising can be defined as a way of internationalization of franchisor to foreign country by providing its business format or package to franchisee of host country. International franchising is growing fast for last four decades but academic research on this is quite limited. Especially in Korea, research about international franchising is carried out on by case study format with single case or empirical study format with survey based on domestic franchise theory. Therefore, this paper tries to review existing literature on international franchising research, providing research framework, and then stimulating new research on this field. International franchising research components include motives and environmental factors for decision of expanding to international franchising, entrance modes and development plan for international franchising, contracts and management strategy of international franchising, and various performance measures from different perspectives. First, motives of international franchising are fee collection from franchisee. Also it provides easier way to expanding to foreign country. The other motives including increase total sales volume, occupying better strategic position, getting quality resources, and improving efficiency. Environmental factors that facilitating international franchising encompasses economic condition, trend, and legal or political factors in host and/or home countries. In addition, control power and risk management capability of franchisor plays critical role in successful franchising contract. Final decision to enter foreign country via franchising is determined by numerous factors like history, size, growth, competitiveness, management system, bonding capability, industry characteristics of franchisor. After deciding to enter into foreign country, franchisor needs to set entrance modes of international franchising. Within contractual mode, there are master franchising and area developing franchising, licensing, direct franchising, and joint venture. Theories about entrance mode selection contain concepts of efficiency, knowledge-based approach, competence-based approach, agent theory, and governance cost. The next step after entrance decision is operation strategy. Operation strategy starts with selecting a target city and a target country for franchising. In order to finding, screening targets, franchisor needs to collect information about candidates. Critical information includes brand patent, commercial laws, regulations, market conditions, country risk, and industry analysis. After selecting a target city in target country, franchisor needs to select franchisee, in other word, partner. The first important criteria for selecting partners are financial credibility and capability, possession of real estate. And cultural similarity and knowledge about franchisor and/or home country are also recognized as critical criteria. The most important element in operating strategy is legal document between franchisor and franchisee with home and host countries. Terms and conditions in legal documents give objective information about characteristics of franchising agreement for academic research. Legal documents have definitions of terminology, territory and exclusivity, agreement of term, initial fee, continuing fees, clearing currency, and rights about sub-franchising. Also, legal documents could have terms about softer elements like training program and operation manual. And harder elements like law competent court and terms of expiration. Next element in operating strategy is about product and service. Especially for business format franchising, product/service deliverable, benefit communicators, system identifiers (architectural features), and format facilitators are listed for product/service strategic elements. Another important decision on product/service is standardization vs. customization. The rationale behind standardization is cost reduction, efficiency, consistency, image congruence, brand awareness, and competitiveness on price. Also standardization enables large scale R&D and innovative change in management style. Another element in operating strategy is control management. The simple way to control franchise contract is relying on legal terms, contractual control system. There are other control systems, administrative control system and ethical control system. Contractual control system is a coercive source of power, but franchisor usually doesn't want to use legal power since it doesn't help to build up positive relationship. Instead, self-regulation is widely used. Administrative control system uses control mechanism from ordinary work relationship. Its main component is supporting activities to franchisee and communication method. For example, franchisor provides advertising, training, manual, and delivery, then franchisee follows franchisor's direction. Another component is building franchisor's brand power. The last research element is performance factor of international franchising. Performance elements can be divided into franchisor's performance and franchisee's performance. The conceptual performance measures of franchisor are simple but not easy to obtain objectively. They are profit, sale, cost, experience, and brand power. The performance measures of franchisee are mostly about benefits of host country. They contain small business development, promotion of employment, introduction of new business model, and level up technology status. There are indirect benefits, like increase of tax, refinement of corporate citizenship, regional economic clustering, and improvement of international balance. In addition to those, host country gets socio-cultural change other than economic effects. It includes demographic change, social trend, customer value change, social communication, and social globalization. Sometimes it is called as westernization or McDonaldization of society. In addition, the paper reviews on theories that have been frequently applied to international franchising research, such as agent theory, resource-based view, transaction cost theory, organizational learning theory, and international expansion theories. Resource based theory is used in strategic decision based on resources, like decision about entrance and cooperation depending on resources of franchisee and franchisor. Transaction cost theory can be applied in determination of mutual trust or satisfaction of franchising players. Agent theory tries to explain strategic decision for reducing problem caused by utilizing agent, for example research on control system in franchising agreements. Organizational Learning theory is relatively new in franchising research. It assumes organization tries to maximize performance and learning of organization. In addition, Internalization theory advocates strategic decision of direct investment for removing inefficiency of market transaction and is applied in research on terms of contract. And oligopolistic competition theory is used to explain various entry modes for international expansion. Competency theory support strategic decision of utilizing key competitive advantage. Furthermore, research methodologies including qualitative and quantitative methodologies are suggested for more rigorous international franchising research. Quantitative research needs more real data other than survey data which is usually respondent's judgment. In order to verify theory more rigorously, research based on real data is essential. However, real quantitative data is quite hard to get. The qualitative research other than single case study is also highly recommended. Since international franchising has limited number of applications, scientific research based on grounded theory and ethnography study can be used. Scientific case study is differentiated with single case study on its data collection method and analysis method. The key concept is triangulation in measurement, logical coding and comparison. Finally, it provides overall research direction for international franchising after summarizing research trend in Korea. International franchising research in Korea has two different types, one is for studying Korean franchisor going overseas and the other is for Korean franchisee of foreign franchisor. Among research on Korean franchisor, two common patterns are observed. First of all, they usually deal with success story of one franchisor. The other common pattern is that they focus on same industry and country. Therefore, international franchise research needs to extend their focus to broader subjects with scientific research methodology as well as development of new theory.