• Journal of Genetic Medicine
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• v.5 no.1
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• pp.26-33
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• 2008

Purpose : Phenylketonuria(PKU) is an inborn error of metabolism and a genetic disorder resulting from a deficiency of phenylalanine hydroxylase(PAH) and decreased activity of tetrahydrobiopterin(BH4).In this study the correlation between the DNA mutation and clinical manifestations was investigated and PAH DNA mutations were compared bewteen Asian and Caucasian populations. Methods : DNA was isolated from peripheral leukocytes. The PAH gene was amplified by Polymerase Chain Reaction(PCR) and the sequence was analyzed with Multiplex Ligation-dependent Probe Amplification(MLPA). Results : We characterized the PAH gene of 102 independent Korean patients with PKU. PAH nucleotide sequence analysis revealed 44 different mutations, including 10 novel mutations comprising 9 missense mutations(N207D, K95del, A447P, G344D, P69S, S391I, A202T, G103S, and I306L) and 1 novel splice-site variant mutation(IVS10-3C>G). R243Q was the most prevalent mutation in this study. A259T has not previously been reported in Asian populations, but we found that this mutation had a frequency of 10.1% in our study. Furthermore, the genotypes of $BH_4$ responsive patients were analyzed and were divided into two groups: $BH_4$ medication-only group and $BH_4$ medication with diet therapy group. In the $BH_4$ medication-only group and $BH_4$ medication with diet therapy group, R241C was the most common mutation. Conclusion : Novel mutations in the PAH gene of PKU patients are still being discovered. Additional information as to the frequency of mutations in the tetrahydrobiopterine responsive gene is also accumulating. We anticipate that knowledge of these PKU gene mutations will assist the diagnosis, genetic counseling, and therapeutic treatment of PKU patients in future.

• Molecules and Cells
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• v.20 no.2
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• pp.235-240
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• 2005

Extracts of pine needles (Pinus densiflora Sieb. et Zucc.) have diverse physiological and pharmacological actions. In this study we show that pine needle extract alters pacemaker currents in interstitial cells of Cajal (ICC) by modulating ATP-sensitive $K^+$ channels and that this effect is mediated by prostaglandins. In whole cell patches at $30^{\circ}C$, ICC generated spontaneous pacemaker potentials in the current clamp mode (I = 0), and inward currents (pacemaker currents) in the voltage clamp mode at a holding potential of -70 mV. Pine needle extract hyperpolarized the membrane potential, and in voltage clamp mode decreased both the frequency and amplitude of the pacemaker currents, and increased the resting currents in the outward direction. It also inhibited the pacemaker currents in a dose-dependent manner. Because the effects of pine needle extract on pacemaker currents were the same as those of pinacidil (an ATP-sensitive $K^+$ channel opener) we tested the effect of glibenclamide (an ATP-sensitive $K^+$ channels blocker) on ICC exposed to pine needle extract. The effects of pine needle extract on pacemaker currents were blocked by glibenclamide. To see whether production of prostaglandins (PGs) is involved in the inhibitory effect of pine needle extract on pacemaker currents, we tested the effects of naproxen, a non-selective cyclooxygenase (COX-1 and COX-2) inhibitor, and AH6809, a prostaglandin EP1 and EP2 receptor antagonist. Naproxen and AH6809 blocked the inhibitory effects of pine needle extract on ICC. These results indicate that pine needle extract inhibits the pacemaker currents of ICC by activating ATP-sensitive $K^+$ channels via the production of PGs.

• The Korean Journal of Physiology
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• v.22 no.2
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• pp.189-206
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• 1988

The effects of ouabain on the contractile and electrical activities were investigated in the isolated preparations of guinea-pig taenia coli, and compared with those of vanadate. Spontaneous contractions were recorded with force transducer, and electrical activites were measured by use of suction electrode, or single sucrose-gap technique. The contractions were induced by the electrical stimulation for 5 seconds every 1 minute with alternating current (60 Hz, 3.0 V/cm) through the platinum electrodes located in parallel with the long axis of the preparation. All experiments were performed in tris-buffered Tyrode solution which was aerated with $100%{\;}O_2$ and kept at $35^{\circ}C$. The results obtained were as follows: 1) Responses of spontaneous contractions to ouabain were concentration-dependent; $10^{-7}M$ ouabain caused a rise of basal tone. Above the concentration of $10^{-6}M$ ouabain, an initial increase followed by a decrease in tension was observed. 2) A continuous spike discharge was induced by the administration of $10^{-7}M$ ouabain. Above $10^{-6}M$ ouabain, a transient initial increase followed by a decrease in spike frequency and amplitude was produced, and finally membrane potential was sustained at a certain level without a spike discharge. 3) The characteristic response to $10^{-7}M$ ouabain was not blocked by the pretreatment with $10^{-7}M$ atropine. 4) The electrically induced contractions were completely suppressed at the concentration of $2{\times}10^{-7}M$ ouabain. These contractions were blocked more rapidly in paralled with the increase in ouabain concentration. 5) Effects of vanadate on the spontaneous activities were quite different from those of ouabain; $10^{-6}M$ vanadate increased the amplitude of contractions and $10^{-5}M$ vanadate increased slightly both amplitude and frequency of spontaneous contractions. $10^{-4}M$ vanadate showed irregular phasic contractions superimposed on the increased basal tone. 6) $10^{-5}M$ vanadate depolarized the membrane potential and shortened the interval between the bursts of spike discharge, whereas $10^{-4}M$ vanadate induced continuous spike discharge with membrane depolarization. 7) Vanadate caused a characteristic inhibitory response to the contractions induced by electrical stimulation; An initial rapid inhibition of tension development and then gradual recovery to a certain level. From the above results, the following conclusions could be made: 1) The rise of basal tone at $10^{-7}M$ ouabain is due to continuous spike discharge without a silent period. The continuous spike discharge is likely to be associated with a slight membrane depolarization caused by the blockage of Na pump. 2) The biphasic response induced by above $10^{-6}M$ ouabain seems to occur by the different mechanisms. The initial increase in tension is associated with depolarization along with an increase in spike frquency, whereas the subsequent relaxation occurs through a non-electrical mechanism. 3) The characteristic response to $10^{-7}M$ ouabain is resulted not from the action on intrinsic nerve terminal, but from its direct action on the membrane of smooth muscle cells. 4) The phasic contractions superimposed on the increased basal tone at the concentration of $10^{-4}M$ vanadate is resulted from the continuous spike discharge with membrane depolarization, of which mechanism remains unknown. 5) The inhibitory action of ouabain on the electrically induced contractions suggests that the increasein intracellular Na in some way inhibits the electrically induced $Ca^{2+}$ influx. The mechanism of vanadate action on the induced contractions remains unknown.

• Journal of Distribution Research
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• v.15 no.3
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• pp.71-110
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• 2010

1. Introduction Today Internet is recognized as an important way for the transaction of products and services. According to the data surveyed by the National Statistical Office, the on-line transaction in 2007 for a year, 15.7656 trillion, shows a 17.1%(2.3060 trillion won) increase over last year, of these, the amount of B2C has been increased 12.0%(10.2258 trillion won). Like this, because the entry barrier of on-line market of Korea is low, many retailers could easily enter into the market. So the bigger its scale is, but on the other hand, the tougher its competition is. Particularly due to the Internet and innovation of IT, the existing market has been changed into the perfect competitive market(Srinivasan, Rolph & Kishore, 2002). In the early years of on-line business, they think that the main reason for success is a moderate price, they are awakened to its importance of on-line service quality with tough competition. If it's not sure whether customers can be provided with what they want, they can use the Web sites, perhaps they can trust their products that had been already bought or not, they have a doubt its viability(Parasuraman, Zeithaml & Malhotra, 2005). Customers can directly reserve and issue their air tickets irrespective of place and time at the Web sites of travel agencies or airlines, but its empirical studies about these Web sites for reserving and issuing air tickets are insufficient. Therefore this study goes on for following specific objects. First object is to measure service quality and service recovery of Web sites for reserving and issuing air tickets. Second is to look into whether above on-line service quality and on-line service recovery have an impact on overall service quality. Third is to seek for the relation with overall service quality and customer satisfaction, then this customer satisfaction and loyalty intention. 2. Theoretical Background 2.1 On-line Service Quality Barnes & Vidgen(2000; 2001a; 2001b; 2002) had invented the tool to measure Web sites' quality four times(called WebQual). The WebQual 1.0, Step one invented a measuring item for information quality based on QFD, and this had been verified by students of UK business school. The Web Qual 2.0, Step two invented for interaction quality, and had been judged by customers of on-line bookshop. The WebQual 3.0, Step three invented by consolidating the WebQual 1.0 for information quality and the WebQual2.0 for interactionquality. It includes 3-quality-dimension, information quality, interaction quality, site design, and had been assessed and confirmed by auction sites(e-bay, Amazon, QXL). Furtheron, through the former empirical studies, the authors changed sites quality into usability by judging that usability is a concept how customers interact with or perceive Web sites and It is used widely for accessing Web sites. By this process, WebQual 4.0 was invented, and is consist of 3-quality-dimension; information quality, interaction quality, usability, 22 items. However, because WebQual 4.0 is focusing on technical part, it's usable at the Website's design part, on the other hand, it's not usable at the Web site's pleasant experience part. Parasuraman, Zeithaml & Malhorta(2002; 2005) had invented the measure for measuring on-line service quality in 2002 and 2005. The study in 2002 divided on-line service quality into 5 dimensions. But these were not well-organized, so there needed to be studied again totally. So Parasuraman, Zeithaml & Malhorta(2005) re-worked out the study about on-line service quality measure base on 2002's study and invented E-S-QUAL. After they invented preliminary measure for on-line service quality, they made up a question for customers who had purchased at amazon.com and walmart.com and reassessed this measure. And they perfected an invention of E-S-QUAL consists of 4 dimensions, 22 items of efficiency, system availability, fulfillment, privacy. Efficiency measures assess to sites and usability and others, system availability measures accurate technical function of sites and others, fulfillment measures promptness of delivering products and sufficient goods and others and privacy measures the degree of protection of data about their customers and so on. 2.2 Service Recovery Service industries tend to minimize the losses by coping with service failure promptly. This responses of service providers to service failure mean service recovery(Kelly & Davis, 1994). Bitner(1990) went on his study from customers' view about service providers' behavior for customers to recognize their satisfaction/dissatisfaction at service point. According to them, to manage service failure successfully, exact recognition of service problem, an apology, sufficient description about service failure and some tangible compensation are important. Parasuraman, Zeithaml & Malhorta(2005) approached the service recovery from how to measure, rather than how to manage, and moved to on-line market not to off-line, then invented E-RecS-QUAL which is a measuring tool about on-line service recovery. 2.3 Customer Satisfaction The definition of customer satisfaction can be divided into two points of view. First, they approached customer satisfaction from outcome of comsumer. Howard & Sheth(1969) defined satisfaction as 'a cognitive condition feeling being rewarded properly or improperly for their sacrifice.' and Westbrook & Reilly(1983) also defined customer satisfaction/dissatisfaction as 'a psychological reaction to the behavior pattern of shopping and purchasing, the display condition of retail store, outcome of purchased goods and service as well as whole market.' Second, they approached customer satisfaction from process. Engel & Blackwell(1982) defined satisfaction as 'an assessment of a consistency in chosen alternative proposal and their belief they had with them.' Tse & Wilton(1988) defined customer satisfaction as 'a customers' reaction to discordance between advance expectation and ex post facto outcome.' That is, this point of view that customer satisfaction is process is the important factor that comparing and assessing process what they expect and outcome of consumer. Unlike outcome-oriented approach, process-oriented approach has many advantages. As process-oriented approach deals with customers' whole expenditure experience, it checks up main process by measuring one by one each factor which is essential role at each step. And this approach enables us to check perceptual/psychological process formed customer satisfaction. Because of these advantages, now many studies are adopting this process-oriented approach(Yi, 1995). 2.4 Loyalty Intention Loyalty has been studied by dividing into behavioral approaches, attitudinal approaches and complex approaches(Dekimpe et al., 1997). In the early years of study, they defined loyalty focusing on behavioral concept, behavioral approaches regard customer loyalty as "a tendency to purchase periodically within a certain period of time at specific retail store." But the loyalty of behavioral approaches focuses on only outcome of customer behavior, so there are someone to point the limits that customers' decision-making situation or process were neglected(Enis & Paul, 1970; Raj, 1982; Lee, 2002). So the attitudinal approaches were suggested. The attitudinal approaches consider loyalty contains all the cognitive, emotional, voluntary factors(Oliver, 1997), define the customer loyalty as "friendly behaviors for specific retail stores." However these attitudinal approaches can explain that how the customer loyalty form and change, but cannot say positively whether it is moved to real purchasing in the future or not. This is a kind of shortcoming(Oh, 1995). 3. Research Design 3.1 Research Model Based on the objects of this study, the research model derived is