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The Effect of Service Failure on the Desire for Betrayal and Retaliatory Behavior - Based on the Moderating Role of the Customer-Service Firm Relationship Quality (서비스 실패요인이 보복행위에 미치는 영향과 관계품질의 조절효과)

  • Kim, Mo Ran;Ahn, Kwang Ho
    • Asia Marketing Journal
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    • v.14 no.1
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    • pp.99-130
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    • 2012
  • Service failure and a poor service recovery may lead loyal customers to try to aggressively punish the service firm. We use perceived betrayal and desire for vengeance as the key constructs to understand customer retaliation. Perceived betrayal is defined as a customer's belief that a firm has intentionally violated what is normative in the context of their relationship. And the desire for vengeance is defined as the retaliatory feelings that consumers feel toward a firm, such as the desire to exert harm on the firm. The perceived betrayal and the desire for vengeance are key antecedents of retaliatory behaviors such as vindictive complaining, negative WOM and third-party complaining for publicity. The empirical results suggest that betrayal is a key motivational factor that lead customers to restore fairness by making use of all means, including retaliation. We also find that relationship quality has effect on a customer's response to a failure in service recovery. As the levels of relationship increases, a violation of the proper fairness has a stronger effect on the sense of betrayal experienced by customers. Considerable research has investigated consumer responses to dissatisfaction. But our study examine the response of outraged and highly frustrated consumers. We focus on emotional and behavioral processes that have not been covered by previous dissatisfaction researches and which are unique to outraged consumers caused by extremely dissatisfied purchase experience. It has recently been pointed out by various mass media that the customers not only have positive effects on the company performance but also put the company in crisis. It has often been reported that one customer's dissatisfaction, for example, never ends as it is, and it tends to grow for retaliating upon the company, depending on the level of seriousness of the dissatisfaction. This sometimes leads to a lawsuit against the company. Our study focuses on the customers' emotional and behavioral responses induced by their extreme dissatisfactions. We divided the customer groups into the customers with high relationship quality and the customers with low relationship quality, and the difference between two groups is examined. The objective of this study is to comprehend the causal relationship between the feeling of betrayal caused by the service failure and the retaliatory behavior triggered by the desire of revenge. Our study is divided into three parts. First, a causal relationship between perceived unfairness and the perceived betrayal and desire for revenge. Second, the effect of the perceived betrayal and desire for revenge on the retaliatory behavior is investigated. Finally, the moderating role of relationship quality in the causal relationship between the unfairness in service recovery and the perceived betrayal is analyzed. This study finds the following empirical results. The distributive unfairness, procedural unfairness and interactional unfairness had significant effects on the perceived betrayal. Especially, the perceived distributive unfairness results in the highest perceived betrayal. When the service company does not provide customers proper and sufficient compensation for the failure, they feel the strong sense of betrayal. And in the causal relationship between the perceived betrayal, desire for revenge and retaliatory behavior, the perceived betrayal has significant effects on e desire for revenge. In addition desire for revenge has significant effects on negative word of mouth, retaliatory complaining behavior and publicity of complaints through third group. Therefore the perceived unfairness has effects on retaliatory behavior through the mediation of the perceived betrayal and desire for revenge. Finally the moderating role of relationship quality was examined in the relationship between the unfairness and perceived betrayal. If the customers experienced the perceived unfairness in the process of service recovery, the customers with high relationship quality feel the stronger perceived betrayal than the customers with low relationship quality do. When they experience the double service failure, the customer group with high relationship quality accumulating the sense of trust feel the more perceived betrayal than the customer with low relationship quality who do not have strong trust. The contribution of this study is to find the effect of the service failure on the retaliatory behavior with the moderating roles of relationship quality. The dimensions of unfairness in service recovery is found to have differential effects on the perceived betrayal, desire for revenge. And these differential effect is moderated by the level of relationship quality.

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A Study on the Turnover Intention and Job Satisfaction of Dental Hygienists (치과위생사의 이직의도와 직무만족도에 관한 연구)

  • Yoon, Mi-Sook;Lee, Kyung-Hee;Choi, Mi-Sook
    • Journal of dental hygiene science
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    • v.6 no.3
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    • pp.147-152
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    • 2006
  • The purpose of this study was to help decrease turnover and to make full use of dental hygienists and to help improve management by managers. After relevant literature and data were reviewed, a survey was conducted on dental hygienists, who worked at dental institutes in different areas, for about four months from September through December, 2004, to find out their turnover intention and job satisfaction level. When the collected data were analyzed, the following findings were given: 1. The collective average of the dental hygienists investigated in job satisfaction was $3.30{\pm}0.70$. By area, they expressed the best satisfaction at a clear role factors with a mean of $3.53{\pm}0.73$, and they were pleased with wages factors and promotion factors the least with an average of $3.14{\pm}0.70$ and $3.18{\pm}0.80$. 2. The collective average of the dental hygienists investigated in turnover intention was $3.23{\pm}0.77$. As for connections between general characteristics and turnover intention, By age, those who aged in 21 and 25 were most intended(p < 0.001). The unmarried dental hygienists were more intended than the married ones(p < 0.001). By type of hospital, those who worked at dental clinics were most intended(p< 0.01). By career, those who had worked at one to three years were intended the most(p < 0.001), and as to the length of service at current work places, those who had worked at their current work places for one to three years were intended the most(p < 0.001). By monthly mean pay, those whose pay ranged from 1.3 to 1.6 million won found their turnover most intended(p< 0.01). 3. Regarding correlation among turnover intention and job satisfaction were both inversed correlationship, and wages factor(r = -0.249, p < 0.01) and interrelationship factors(r = -0.218, p < 0.01) had a strong correlation to turnover intention, and clear role factors had a strong correlation to job contents factors by job satisfaction(r = 0.612, p < 0.01), and job satisfaction factors had a strong correlation to job contents factors(r = 0.759, p < 0.01).

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A Study of Teaching Effectiveness on Clinical Nursing Education (임상간호 실습교육의 교수효율성에 관한 연구)

  • 김미애
    • Journal of Korean Academy of Nursing
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    • v.26 no.4
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    • pp.946-962
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    • 1996
  • The purpose of this study was to contribute to the development of clinical instruction by students' ratings of teaching effectiveness in clinical nursing education. The subjects were comprised of graduating class 618 students from 24 nursing colleges in the nation. The instruments used in this study were "general characteristics & status of clinical nursing education" developed by the researcher and "Instrument to Measure Effectiveness of Clinical Instructors" by Reeve(1994). The 50 questions used in the questionaire were categorized into 13 components subject to factor analysis. The 13 components were interpersonal relationships, communication skills, role model, resource for students, favorable to students, encouraging to think for selves, teaching methods, evaluation, finding assignments for objectives, organization of subject matter, professional competence, knowledge of subject matter & working with agency personnel. The results of this study are as follows 1. Status of clinical nursing educaion : 1) Clinical nursing education were led by nursing professors(44.9%), a team of both nuring professor & head nurse(6.8%), instructors from specific hospital(15.1%), instuctos for a specific subject(14.6%), & head nurse(6.8%). For 3-year program students, 34.6% of the clinical nursing education were led by instructors from specific hospital & 51.4% of the education by nursing professors for Bachelor's program. 2) The contents for clinical education comprised of Conference being the most frequent of 34.5% ; a combination of Nursing skills, Orientation, Conference etc.22.0% : Nursing process 21.7% : Orientation 13.5% : Inspection(making rounds ) 6.4%, & Nursing skills of 2% being the least frequent. 3) Students' preference of clinical teachers from the highest to the lowest were instructors for a specific subject being the most desired (44.9%) followed by nursing professor, head nurse, a team of both nursing professor & head nurse, & instructors from specific hospital being the least desired. 4) Students felt that the qualification for clinical teachers should be at least a master's degree holder and 5 or more years of clinical experience. The reason they felt was because knowledge & experience are imperative for professional education. 2. Clinical teaching effectiveness : The total points for teaching effectiveness was 147.97(mean of 2.95±0.98) where the total score is considered to be an average rating. 3. Teaching effectiveness as status of clinical nursing education : 1) The score ratings for the clinical instructors from the highest to the lowest were as follows : instructors for a specific subject, instructors from specific hospitals, a team of both nursing professors & head nurses, nursing professors, head nurses, which resulted in significunt difference(F=4.53, P<0.001). 2) The rating scores based on the teaching program from the highest to the lowest were as follws ; nursing skills, nursing process, a combination of nursing skills, orientation, conference etc. , conferences, orientation, inspection, which resulted in significunt difference(F=10.97, P<0.001). 4. Based on 13 categorized components from the questionaires, questions related to communication skills scored the highest points of 3.20 where inquiries regarding resource for students scored the lowest points of 2.38. 5. Among the 13 categorial components from the questionaire, Interpersonal relationship, Communication skills, Resource for students, Encouraging to think for selves, Evaluation, Teaching method, Finding assignment for objectives, Organization of subject matter, Professional competence, & Working with agency personnel, instructors for a specific subject scored the highest points and head nurse scored the lowest, which resulted in significant difference. Favorable for students, instructors for a specific subject scored highest points and nursing professor scored the lowest, which resulted in significant deference (F=5.39, P<0.001). Role model & Professional competence, instructors for a specific subject scored the highest points and head nurse scored the lowest, with minimum variation(F=1.29, P>0.05 : F=1.64, P>0.05) 6. Based on 13 categorial components as a whole, the highest points scored among the 5 groups of clinical teachers was instructors for a specific subject and the lowest, by head nurse(F=1.94, P<0. 001). A team of both nursing professor & head nurse attained higher score in clinical education than their independent education.

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World Logistics Evolution & Marketing Strategy for Korea's Enhanced Port Competition (세계물류발전과 한국의 항만경쟁력 강화를 위한 마케팅 전략)

  • Gim, Jin-Goo
    • Journal of Korea Port Economic Association
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    • v.24 no.4
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    • pp.363-384
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    • 2008
  • This study aims at improving Korea's competitiveness in port logistics through marketing strategy with integrating the conceptual approach into the empirical one and combining both the oldest military treatise and the newest evaluating model in social science that was applied by the HFP(hierarchical fuzzy process) model enhanced by the KJ method. The empirical results of this study show Busan in the middle among subject ports. At present, Korea plays a reciprocal role in the port market in East Asia, but in the medium- and long-term, Korea's ports will vie together with most major ports in the East Asian region. A descriptive investigation shows that Korea's developing tasks in port logistics must be considered in the context of the direction for developing port policies, the necessity of expanding port facilities in the capital region, securing the sufficient traffic volume through the establishment of the hinterland linking system and its positive utilization, and reforming the direction for developing the global logistics through increased port competitiveness. In the short- and medium-term, Korea must use the opportunity factor of 'Growth and open door policy of China' as a geoeconomic advantage and to utilize Korea's ports as a gate to Chinese foreign trade. With the rise of China's economy, China also plays a significant role in both port and airport markets. Hence, the linking system between the two must be established to meet the expanding traffic volume, especially in the capital area. Moreover, it is necessary for Korea to secure port logistics through the establishment of the hinterland linking system and its positive utilization. The great accomplishment of this paper is to present strategies to increase Korea's port competitiveness in the rapidly changing environments of world logistics with the focus on both the oldest military strategic treatise and the newest empirical method in social science. In order to reinforce this study, it needs further compensative research because the evaluation structure could be subdivided with more extensive and precise criteria.

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The Role of Postoperative Pelvic Radiation Therapy in Rectal Cancer (직장암에 있어서 수술후 방사선치료의 역할)

  • Ahn, Yong-Chan;Kim, Jae-Sung;Yun, Hyong-Geun;Ha, Sung-Whan;Park, Charn-Il
    • Radiation Oncology Journal
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    • v.9 no.1
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    • pp.93-102
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    • 1991
  • To evaluate the role of postoperative pelvic radiation therapy in rectal cancer, a retrospective analysis was done on 189 patients with modified Astler-Coiler stages B2+3, Cl , and C2+3 who were treated from February 1979 to June 1980. Forty-seven patients were staged as B2+3,17 as Cl, and 125 as C2+3. As a curative resection,41 received low anterior resection,143 received abdomino-perineal resection, and five received pelvic exenteration. The survival and disease-free survival rates of the total patients at five year were $45.3\%\;and\;44.1\%$, respectively. The stage was an important prognostic factor for survival and disease-free survival: the survival rates at five year were $63.4\%$ in stage B2+3, $62.4\%$ in C1, and $37.2\%$ in C2+3 (p<0.005): the disease-free survival rates at five year were $55.7\%$ in B2+3, $65.7\%$ in C1, and $30.4\%$ in C2+3, respectively (p<0.01). The liver was the most frequently involved organ of recurrence followed by the lung and the perineum. The patients who received low anterior resection achieved better disease-free survival but were more prone to late radiation bowel morbidities than those who received abdominoperineal resection. Postperative Pelvic radiation therapy Proved to be effective in locoregional disease control but did not prevent the appearance of distant metastasis, which was of major concern in advanced stages. Patterns of treatment failure, and factros relating to radiation morbidity are discussed, and therapeutic options for better results are proposed.

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A Study on Qulity Perceptions and Satisfaction for Medical Service Marketing (의료서비스 마케팅을 위한 품질지각과 만족에 관한 연구)

  • Yoo, Dong-Keun
    • Journal of Korean Academy of Nursing Administration
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    • v.2 no.1
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    • pp.97-114
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    • 1996
  • INSTRODUCTION Service quality is, unlike goods quality, an abstract and elusive constuct. Service quality and its requirements are not easily understood by consumers, and also present some critical research problems. However, quality is very important to marketers and consumers in that it has many strategic benefits in contributing to profitability of marketing activities and consumers' problem-solving activities. Moreover, despite the phenomenal growth of medical service sector, few researchers have attempted to define and model medical service quality. Especially, little research has focused on the evaluation of medical service quality and patient satisfaction from the perspectives of both the provider and the patient. As competition intensifies and patients are demanding higher quality of medical service, medical service quality and patient satisfaction has emerged as a critical research topic. The major purpose of this article is to explore the concept of medical service quality and its evaluation from both nurse and patient perspectives. This article attempts to achieve its purpose by (1)classfying critical service attibutes into threecategories(satisfiers, hygiene factors, and performance factors). (2)measuring the relative importance of need criteria, (3)evaluating SERVPERF model and SERVQUAL model in medical service sector, and (4)identifying the relationship between perceived quality and overall patient satisfaction. METHOD Data were gathered from a sample of 217 patients and 179 nurses in Seoul-area general hospitals. From the review of previous literature, 50 survey items representing various facets of the medical service quality were developed to form a questionnaire. A five-point scale ranging from "Strongly Agree"(5) to "Strongly Disagree"(1) accompanied each statement(expectation statements, perception statements, and importance statements). To measure overall satisfaction, a seven-point scale was used, ranging from "Very Satisfied"(7) to "Very Dissatisfied"(1) with no verbal labels for scale points 2 through 6 RESULTS In explaining the relationship between perceived performance and overall satisfaction, only 31 variables out of original 50 survey items were proven to be statistically significant. Hence, a penalty-reward analysis was performed on theses 31 critical attributes to find out 17 satisfiers, 8 hygiene factors, and 4 performance factors in patient perspective. The role(category) of each service quality attribute in relation to patient satisfaction was com pared across two groups, that is, patients and nurses. They were little overlapped, suggesting that two groups had different sets of 'perceived quality' attributes. Principal components factor analyses of the patients' and nurses' responses were performed to identify the underlying dimensions for the set of performance(experience) statements. 28 variables were analyzed by using a varimax rotation after deleting three obscure variables. The number of factors to be extracted was determined by evaluating the eigenvalue scores. Six factors wereextracted, accounting for 57.1% of the total variance. Reliability analysis was performed to refine the factors further. Using coefficient alpha, scores of .84 to .65 were obtained. Individual-item analysis indicated that all statements in each of the factors should remain. On 26 attributes of 31 critical service quality attributes, there were gaps between actual patient's importance of need criteria and nurse perceptions of them. Those critical attributes could be classified into four categories based on the relative importance of need criteria and perceived performance from the perspective of patient. This analysis is useful in developing strategic plans for performance improvement. (1) top priorities(high importance and low performance) (in this study)- more health-related information -accuracy in billing - quality of food - appointments at my convenience - information about tests and treatments - prompt service of business office -adequacy of accommodations(elevators, etc) (2) current strengths(high importance and high performance) (3)unnecessary strengths(low importance and high performance) (4) low priorities(low importance and low performance) While 26 service quality attributes of SERPERF model were significantly related to patient satisfation, only 13 attributes of SERVQUAL model were significantly related. This result suggested that only experience-based norms(SERVPERF model) were more appropriate than expectations to serve as a benchmark against which service experiences were compared(SERVQUAL model). However, it must be noted that the degree of association to overall satisfaction was not consistent. There were some gaps between nurse percetions and patient perception of medical service performance. From the patient's viewpoint, "personal likability", "technical skill/trust", and "cares about me" were most significant positioning factors that contributed patient satisfaction. DISCUSSION This study shows that there are inconsistencies between nurse perceptions and patient perceptions of medical service attributes. Also, for service quality improvement, it is most important for nurses to understand what satisfiers, hygiene factors, and performance factors are through two-way communications. Patient satisfaction should be measured, and problems identified should be resolved for survival in intense competitive market conditions. Hence, patient satisfaction monitoring is now becoming a standard marketing tool for healthcare providers and its role is expected to increase.

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Usefulness of $^{201}Tl$ Myocardial Perfusion SPECT in Prediction of Left Ventricular Remodeling following an Acute Myocardial Infarction (급성심근경색 후 발생하는 좌심실 재구도 예측에 대한 $^{201}Tl$ 심근관류 SPECT의 운용성)

  • Yoon, Seok-Nam;Park, C.H.;Hwang, Kyung-Hoon
    • The Korean Journal of Nuclear Medicine
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    • v.34 no.1
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    • pp.30-38
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    • 2000
  • Purpose: We investigated the role of myocardial perfusion SPECT in prediction of ventricular dilatation and the role of revascularization including thrombolytic therapy and PTCA in prevention of ventricular dilatation after an acute myocardial infarction (AMI). Materials and Methods: We performed dipyridamole stress, 4 hour redistribution, and 24 hour reinjection Tl-201 SPECT in 16 patients with AMI two to nine days after attack. Perfusion and wall motion abnormalities were quantified by perfusion index (PI) and wall motion index (WMI). Left ventricular ejection fraction (LVEF), WMI and ventricular volume were measured within 1 week of AMI and after average of 6 months. According to serial changes of left ventricular end-diastolic volume (LVEDV), patients were divided into two groups. We compared WMI, PI and LVEF between the two groups. Relationships among degree of volume, stress-rest PI, WMI, CKMB, Q wave, LVEF and revascularization were analysed using multivariate analysis. Results: Only initial rest perfusion index was significantly different between the two groups (p<0.05). While initial LVEF, stress PI, CKMB, trial of revascularization procedure, presence of Q wave and WMI were not significantly different between the two groups. Eight of 16 patients (50%) showed LV dilatation on follow-up echocardiography. Three of 3 patients (100%) who did not undergo revascualrization procedure documented LV dilatation. And only 5 (38%) of the remaining 13 patients who underwent revascularization revealed LV dilatation. There was no difference in infarct location between the two groups. By multivariate linear regression analysis in patients only undergoing revascularization, rest perfusion index was the only significant factor. Conclusion: Myocardial perfusion SPECT performed prior to revascularization was useful in prediction of LV dilatation after an AMI. Rest perfusion index on myocardial perfusion plays as a significant predictor of left ventricular dilatation after AMI. And revascularization appears to be a valuable procedure in alleviating LV dilatation after AMI with or without viable myocardium in a limited number of patients studied retrospectively.

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Historical Evolution of Stage Costumes in Europe since the Second World War (제2차 세계대전 이후 나타난 유럽 무대의상의 사적 분석)

  • Na, In-Wha;Lee, Kyu-Hye
    • Journal of the Korean Society of Clothing and Textiles
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    • v.31 no.12
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    • pp.1761-1771
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    • 2007
  • The artificial exaggeration of stage costumes is thought to be one of the major techniques of enhancing dramatic expression on stage, whichever for visual impact or symbolic effect of dramatization. In the history of stage dressing, a variety of styles has been tried using different materials and production techniques. This may be reviewed as an effort to express dramatic effects more effectively. As this trend became obvious in Europe after the Second World War, this study analyzes the stage costume to deepen our understandings of the role of costumes in expressing dramatic effects. To accomplish this, we first summarized the history of stage costume materials and technical advance and chose five major cases representing the history of stage costume since the Second World War in Europe based on aesthetic and creative aspects: 1) Simplified stage of Jacques Copeau, 2) Stylized stage of Bertolt Brecht, 3) Essential stage of Grotowski, 4) Measured stage of Robert Wilson the Master, and 5) Post-dramatic stage of Philippe $Decoufl\'{e}$. In each of particular case, the historical, material and dramatic contexts were examined as well as different material-effects. The results are as followings: 1) Costume for Copeau's simplified stage: its simplicity plays a supporting role to the gesture of actors(intensifying effect). 2) Costume for Brecht's stylized stage: the artificial stylization integrates into the play with the importance approximately equal to the actors's acting. 3) Costumes for Grotowski's essential stage: costumes disappeared to emphasize only actor's presence on stage. 4) Costumes for Robert Wilson's measured stage: costumes made concrete impression to the extent of obtaining the same importance of actor's body among other stage art elements(lighting, sound, props, actor, text, etc). 5) Costumes for Decoufle's post-dramatic stage: costumes in the era of multi technology possess multi functional aspects that surrogate actors' body. This study suggests that stage costumes take an important part in dramaturgy to the extent that the intent of dramaturgy can be induced enough from stage costume. Thus, costume makers are expected to incorporate the appropriate dramatic factor more than before.

A Study on the Goal-Orientation of QI Performers in the Medical Centers (의료기관 QI 담당자의 목표추구몰입에 관한 연구)

  • Kim, Mi-Sook;Park, Jae-Sung
    • The Korean Journal of Health Service Management
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    • v.2 no.1
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    • pp.105-124
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    • 2008
  • The purpose of this research is to provide the data base for the activation of Quality Improvement operation through investigating the status of Quality Improvement operation, and finding out factors influencing on the goal-orientation of QI performers in the medical centers of more than one hundred beds where are practicing Quality Improvement operation. In order to reach the purpose, document study was carried out grounded on the proceeding researches and formulated statistical data in relation with the status of Quality Improvement performers, and proof study was carried out through questionnaire survey. The subjects of the survey were the Quality Improvement performers working in seventy three medical centers in Pusan-Gyeongnam, Daegu-Gyeongbuk, and Ulsan. Among eighty three Quality Improvement performers, fifty, five were questionnaire surveyed, on the result of which Reliability Analysis, Factor Analysis, and Multiple Regression Analysis were made, using statistical program. The the results of the proof analysis on this research are as follows. First, in the factors influencing the devoting to goal pursuit of QI performers, organization-goal contribution(0.44) had significant positive effects, while organization conflict(-0.25) had significant negative effects. In other words, the higher the organization-goal contribution was, the higher the devoting to goal pursuit was, while the less the organization conflict was, the higher the devoting to goal pursuit was, which was statistically significant.(p<0.05). Second, in the aspect of goal performance types of QI performers, the process-centered type showed high level of the devoting to goal pursuit, which was statistically significant.(p<0.05). Third, in the aspect of QI performance degree, the higher the devoting to goal pursuit was, the higher the QI performance degree was, which was statistically significant.(p<0.05). In addition, the performers who perceived their workplaces organic structure showed much higher QI performance degree, which statistically significant.(p<0.05). Generalizing the results of this research, it is possible to offer a few suggestions as follows. First, as the competition among the medical centers is more severe recently owing to medical center evaluation system, medical centers are practicing various Quality Improvement operation in all of medical services such as clinical performance and management performance, to reach the purpose of both cost-cutting and medical quality improvement. Thus in order to practice Quality Improvement operation more efficiently in medical centers, it is essential to nuke use of problem-solving methods and statistical members. This as the willingness of chief executives and positive attitude and recognition of organization members. This requires the installation of divisions in charge and disposition of persons in charge, not to speak of persistent training of Quality Improvement. Second, the divisions in charge of QI carry out Quality Improvement operation at the medical center level, and take the role of generalizing and adjusting QI performances of various departments. Owing to this role, the division in charge of QI is considered indispensable organization in the QI operation of medical centers along with medical QI committee, while it contributes to the government's goal of reducing quality level gaps among medical centers. Therefore it is necessary for government and QI organizations to give institutional support and resources for the sake of QI operation of medical centers, besides to supply systematic trainning and informations to the divisions and persons in charge of QI. Third, it is certain that disposition of persons in charge should be determined in view of the scale and the scope of QI operation in medical centers.

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Recent Advancement in the Differentiation of Tissues and Organs and Regulation of Gene Expression (조직.기관의 분화와 유전자 발현의 조절, 최근의 진보)

  • Harn, Chang-Yawl
    • Korean Journal of Plant Tissue Culture
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    • v.24 no.1
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    • pp.1-35
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    • 1997
  • Fertilized egg, by successive cell divisions, differentiates into different tissues and organs with various structures and functions. Different cells and tissues contain different proteins, products of selective gene expression. Not all the genes in any genomes are equally active, temporal and spatial gene expression being the general rule. Present paper attempts to review the tanscriptional mechanisms or the initiations of transcription from several angles. In some of the organisms the genes in the process of transcription or the genes in the inactive state can be seen under the light microscope. Some bands of Drosophila polytene chromosomes may exhibit a swollen or puff appearance under certain conditions. A puff, unfolded or decondensed form of chromomere, represents sets of intense transcriptional activity or RNA synthesis. The heterochromatic X chromosome whose genes remain inactive in the female mammals can be visualized as a dark staining structure called Barr body, Configuration of chromatin differs between transcribed and nontranscribed chromatin. Modification to the chromatin facilitates RNA synthesis. The movement of large polymerase molecule along the DNA would probably be facilitated if some modifications of the chromatin configuration is effected. Methylation of cytosines in CG sequences is associated with inactive genes. Methylation can play a role in determination of mammalian cells during embryogenesis. Demethylation is necessary for the gene to be expressed during development A histone modification that is also known to be correlated with transcriptional capacity of chromatin is acetylation of the lysine residues of the core histones. Chromatin containing a high level of histone acetylation is very sensitive to DNase 1. For the transcription to occur TBP must first bind to the TATA box. Another TF, TF IIB, then binds to the promoter-TBP complex, facilitating the access of RNA polymerase to the transcription initiation site. As recently as eight years ago researchers assumed that histones were irrelevant to the regulation of gene expression. Histones combine with the DNA to form nucleosome of the chromatin. Histones are vital participant in gene regulation. Histone and basal factors compete for access to TATA box. When DNA is exposed to basal factors before histones are introduced, the basal factors assemble on TATA boxes preventing the access of histones, allowing transcription to occur, for transcription to begin, activator protein at the upstream activation sequence or enhancer must interact with the tail of histone H4 at TATA box and cause the histone role particle to dissociate from the TATA box leading to partial breakup of the histone core particle and allowing the basal factors to bind to the TATA box. New concept of genomic flux in contrast to the old concept of static genome has been developed based on the powerful new molecular techniques. Genomic changes such as repetitive DNAs and transposable elements, it is assumed but not yet proved, may affect some of the developmental patterns that characterize particular cells, tissues, organs, and organisms. In the last decade or so remarkable achievement have been made in the researches of the structures and functions of TFs and the specific target sequences located in promoters or enhancers where these TFs bind. TFs have independent domains that bind DNA and that activate transcription. DNA binding domain of TFs serves to bring the protein into the right location. There are many types of DNA binding domains. Common types of motifs can be found that are responsible for binding to DNA. The motifs are usually quite short and comprise only a small part of the protein structure. Steroid receptors have domains for hormone binding, DNA binding, and activating transcription. The zinc finger motif comprises a DNA binding domain. Leucine zipper consist of a stretch of amino acids with a leucine residue in every seventh position Two proteins form a dimer because they interact by means of leucine zippers on similar α-helical domain. This positions their DNA binding basic domains for interaction with the two halves of a DNA sequence with dyad symmetry of TGACTCA, ACTGAGT.

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