• Korean Journal of Veterinary Service
• /
• v.33 no.1
• /
• pp.29-35
• /
• 2010

This study was performed to test the hypothesis that Brucella abortus strain RB51 (SRB51) might protect Korean indigenous mongrel dog against challenge with either virulent B. abortus biotype 1 or B. canis. A total of 12 Korean mongrel dogs were divided into four groups (Group A, B, C and D). Dogs belonging to Group A and C were inoculated subcutaneously with $1{\times}10^9$ CFU of SRB51 in 1ml of sterile phosphate buffered saline (PBS). Dogs of Group B and D were inoculated subcutaneously with 1ml of sterile PBS as control. At 12 weeks post vaccination, dogs of Group A and B were challenged by oral inoculation of virulent strain of B. canis ($5.0{\times}10^9$ CFU) and dogs of Group C and D were challenged by oral inoculation of virulent strain of B. abortus biotype 1 ($4.4{\times}10^{10}$ CFU). The serum antibodies titers in all dogs were monitored at regular interval for eight weeks after challenge (AC) by standard tube agglutination test, plate agglutination test, rose bengal test, 2-mercaptoethanol rapid slide agglutination test and 2-mercaptoethanol tube agglutination test. No antibody titers in Group A and C was detected. Also, the challenge strains were not found from blood of all dogs of Group A and C from 1 week AC till the end of the experiment by culture and modified AMOS-PCR, whereas B. canis and B. abortus challenge strains were detected from blood of Group B and D, respectively. In addition, neither of two challenge bacteria was recovered from liver, spleen, kidneys, lymph nodes and reproductive tracts of Group A and C dogs after postmortem. However, B. canis and B. abortus challenge strains were isolated from these tissues of Group B and D, respectively. These data suggest that SRB51 could be a promising vaccine candidate for immunizing dogs to control canine brucellosis caused by B. canis or B. abortus.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.20 no.1
• /
• pp.22-26
• /
• 2017

Purpose: The diagnosis of cow's milk (CM) allergy is a challenge. The Cow's Milk-related-Symptom-Score ($CoMiSS^{TM}$) was developed to offer primary health care providers a reliable diagnostic tool for CM related symptoms. The predictive prospective value of the $CoMiSS^{TM}$ was evaluated in three clinical trials. Methods: Pooled analyses of the three studies were conducted based on regressing the results of the month-1 challenge test on the month-1 $CoMiSS^{TM}$, adjusting for baseline $CoMiSS^{TM}$ using a logistic regression model. In addition a logistic regression model was also fitted to the month-1 challenge test result with the change in $CoMiSS^{TM}$ from baseline as a predictor. Results: Results suggest that infants having a low $CoMiSS^{TM}$ (median, 5) after 1 month dietary treatment free from intact CM protein have a significant risk of having a positive challenge test (odds ratio, 0.83; 95% confidence interval, 0.75-0.93; p=0.002). Pooled data suggest that the change in $CoMiSS^{TM}$ from baseline to month-1 can predict CM related symptoms as a confirmed diagnosis according to the challenge test at month-1. However, in order to validate such a tool, infants without CM related symptoms would also need to be enrolled in a validation trial. A concern is that it may not be ethical to expose healthy infants to a therapeutic formula and a challenge test. Conclusion: Pooled data analysis emphasizes that the $CoMiSS^{TM}$ has the potential to be of interest in infants suspected to have CM-related-symptoms. A prospective validation trial is needed.

• Journal of the Korean Home Economics Association
• /
• v.49 no.6
• /
• pp.85-94
• /
• 2011

The purpose of this study was to validate the Korean Family Support & Challenge Questionnaire (K-SCQ), which is designed to assess family complexity in Children. There were 258 pre-test participants in this study and 498 senior students who were in elementary school. Results from the pre-test suggested us to use Likert scale over a dichotomous agree or disagree scale and positively items over negative ones. Results of the confirmatory factor analysis showed that the two factor structure (family support and challenge) of the SCQ fits well for Korean students. The K-SCQ has also good internal consistency. Further analysis was performed to explore the relationships between four family types based on K-SCQ and children's well-being and flow experience. It showed that the children in a high support/high challenge family had the highest emotional well-being, psychological well-being, and flow experience. These results suggest that the complex family characterized by high support and challenge has strong and positive impact on the children's quality of life.

• The Journal of Korean Society of Virology
• /
• v.26 no.1
• /
• pp.67-76
• /
• 1996

The methods that make Hantavirus grow consist of inoculation into the experimental animals and cultured cells. The cultured cells, such as Vero-E6 and A549 cells, have been usually used for isolation of the virus and the animals, such as mice and rats, are used for large scale preparation of the virus so far. Furthermore, the cell can be used to maintain the virus and assay the infectivity and the animals can be used for the experiment of viral pathogenicity and challenge for assessment of vaccine. Apodemus mice, the own natural host of the virus, has been used for challenge test of Hantaan virus. However it has been pointed out to difficult handling and breeding the animal in laboratory. Therefore, we attempted to establish a new animal model for challenge test at the time of isolation of Maaji virus which is a new hantavirus similar but distinct to Hantaan virus. In suckling hamster, the titer of Maaji virus and the lethality to mice of the virus were increased gradually in the titer and lethality through passage by intracerebral (IC) inoculation. We tried to re-adapt this brain virus to lung of weanling hamster. The brain passaged virus was inoculated into weanling hamster intramuscularly. Again, the titer of the virus in lung was also increased by continuous passage of this virus. This facts could regarded as adaptation to new environment in which the virus proliferates. To identity the virus passaged in hamster with Maaji virus, both of the virus passaged in hamster brain and lung were compared with Maaji virus (MAA-I) and Hantaan virus (HTN 76-118) by means of restriction fragment length polymorphism (RFLP) and slingle strand conformation polymophism (SSCP). As a result, we conclude that Maaji virus could be adapted successfully to weanling hamster through this passage strategy. Utilizing this adapted Maaji virus strain, hamster model is able to be used for challenge test in hantaviral vaccinology and further experiments utilizing hamster system as a rather available and convenient lab animal are expected.

• Korean Journal of Veterinary Research
• /
• v.46 no.3
• /
• pp.185-196
• /
• 2006

Newcastle disease (ND) is a highly contagious disease of poultry that can cause severe economic losses throughout the world. Vaccination has been used for a long time and proved as one of the most effective method to reduce the economic loss due to ND virus infection, The measurement of antibody titer such as hamagglutination-inhibition (Hl) test with sera has been used as a useful method to evaluate the immunity leve of host. However, Hl test is gradually being replaced by the enzyme linked-immunosorbent assay (ELISA), To evaluate the efficacy of ELISA in the chickens vaccinated with different procedure, present study has been performed. After SPF chicks and commercial broilers were vaccinated with different kinds of live vaccines such as V4, VG/GA and/or Bl at various time, the antibody level has been measured using both HI test and ELISA. Challenge test with velogenic viscerotropic NDV was also performed to measure the protective level of antibody. In the SPF chickens, the mean ELISA titer after vaccination and survival rate after challenge was increased and correlated with days post inoculation. More than 80% of chickens with higher than 1,000 ELISA titer after vaccination were survived after challenge with velogenic ND virus and had good correlation between survival rate and antibody titier. In commercial broiler chickens, most of them at market age had low level of ELISA titer regardless of the number of vaccination, and had a low correlation between survival rate and ELISA titer. However, the ELISA titer of remaining birds after challenge was increased. This result indicated that ELISA titer had good response against velogenic NOV infection compared to Hl titer.

• Tuberculosis and Respiratory Diseases
• /
• v.45 no.4
• /
• pp.723-735
• /
• 1998

Background : Vitamin C has been reported to have a role in the decrease of airway hyperresponsiveness in animal models. This data is based on some metabolic actions of vitamin C, such as promotion of histamine degradation, producing more $PGE_2$ than $PGF_{2\alpha}$ in cyclooxygenase pathway, decrease of smooth muscle contraction, and acting as reducing agent of oxidant. It has been also known that heavy smokers have lower blood levels of vitamin C than nonsmokers and this deficiency in heavy smokers have been explained by several mechanisms, such as increased oxidation by oxidants and free radicals, increased biosynthesis of catecholamine and serotonin released by nicotine, and inadequate dietary intake. In this study, We attempted to assess effect of vitamin C on bronchial hyperresponsiveness in heavy smokers who have bronchial hyperresponsiveness and role of vitamin C on bronchial hyperresponsiveness. Method: To assess acute effect of vitamin C on airway hyperresponsiveness, blood sample for vitamin C level and spirometry, methacholine challenge test were done in 17 smokers and 8 nonsmokers, and one hour after oral administration of vitamin C 3 g, blood sample for vitamin C level and spirometry, methacholine challenge test were repeated. To assess chronic effect of vitamin C on airway hyperresponsiveness, after daily administration of vitamin C 1 g for one week in 17 smokers, blood sample for vitamin C level and spirometry, methacholine challenge test were done. To assess role of vitamin C, after oral administration of vitamin C 3 g plus indomethacin 100 mg in 12 of 15 smokers who were reactive to methacholine challenge test, spirometry and methacholine challenge test were done and after oral intake of indomethacin 100 mg in 12 smokers who were reactive to methacholine challenge test, spirometry and methacholine challenge test were repeated. Result: There were no significant differences in whole blood vitamin C levels between smokers($1.17{\pm}0.22$ mg/dL) and nonsmcikers($1.14{\pm}0.19$ mg/dL) (p>0.05). Fifteen of the 17 smokers(88.2%) were reactive to methacholine challenge test and 10 of the 15 smokers who were reactive to methacholine challenge test were less than 8 mg/dL in $PC_{20}FEV-2$, and 7 of the 8 nonsmokers(87.5%) were nonreactive to methacholine challenge test There were significant decrease in bronchial responsiveness after oral administration of vitamin C 3 g in 13 of the 15 smokers who were reactive to methacholine challenge test This significant decrease persisted with maintenance daily administration of 1 g for one week. $PC_{20}FEV-2$ were not correlated to vitamin C levels in smokers. After oral administration of indomethacin 100 mg, significant reduction of bronchial responsiveness that occured after oral administration of vitamin C 3 g in smokers were attenuated. Conclusion: Although there were no significant differences in whole blood vitamin C levels between smokers and nonsmokers. heavy smokers have significant increase in bronchial responsiveness than nonsmokers. This bronchial hyperresponsiveness of heavy smokers can be attenuated by vitamin C supplement. Disappearance of vitamin C effect by indomethacin supplement may suggest that vitamin C exert its effect via alteration of arachidonic acid metabolism.

• Fashion, Industry and Education
• /
• v.14 no.1
• /
• pp.10-17
• /
• 2016

The purpose of this study is to examine the difference between perceived challenges measured before and after shopping online for fashion products and their effects in leading to flow. An online survey including an online shopping task was conducted with a national sample of 500 adult consumers recruited in the U.S.A. The paired t-test results show that perceived challenge measured before the task is significantly higher than perceived challenge measured after the task. ANOVA results further show that the interaction effect between skill and challenge on flow is significant only when perceived challenge is measured after that task. Implications of the findings and recommendations for further research are also discussed.

• Journal of Veterinary Clinics
• /
• v.15 no.1
• /
• pp.46-55
• /
• 1998

This study was performed to verify the effect of modified live virus vaccine against canine parvovirus (CPV) infection. Serum hemagglutination inhibition (Hl) test, histopathological and immunohistochemical techniques and polymerase chain reaction were used. The results were as follows: 1. During the experimental terms after vaccination, serum Hl titer was stable. Geometric mean titer (GMT) after the 1st vaccination was 280. After virulent CPV was challenged, GMT was 1,306. 2. After challenge by virulent CPV, the vaccinated group was not shown clinical signs and gross and histopathological findings. 3. After challenge by virulent CPV, the vaccinated group was not detected viral antigens in the small intestine immunohistochemically. 4. After challenge by violent CPV, the vaccinated group was not shown virus shedding in feces. In conclusions the overall results confirmed that modified live virus vaccine was effective on prevention of canine parvovirus infection.

• Asian-Australasian Journal of Animal Sciences
• /
• v.26 no.1
• /
• pp.90-96
• /
• 2013

Effects of dietary Scutellaria baicalensis extract (SBE) on growth, feed utilization and challenge test of olive flounder (Paralichthys olivaceus) were determined. Six hundred thirty fish averaging 5.0 g were distributed into 18, 180-L tanks. Six experimental diets were prepared in triplicate: SBE-0, SBE-0.5, SBE-1, SBE-2, SBE-3 and SBE-5 diets containing SBE at the concentrations of 0, 0.5, 1, 2, 3 and 5%, respectively. Fish were hand-fed to apparent satiation twice a day for 8 wks. At the end of 8-wk feeding trial, ten fish from each tank were infected by Edwardsiella tarda for challenge test. Survival and weight gain of fish were not affected by dietary concentrations of SBE. However, specific growth rate of fish fed the SBE-2 diet was higher than that of fish fed the SBE-0, SBE-1, SBE-3 and SBE-5 diets. Neither feed efficiency nor serum chemical composition of fish was affected by dietary concentrations of SBE. The cumulative mortality of fish fed the SBE-0 diet was 100% at 96 h after E. tarda infection, but 77 to 87% for fish fed the other diets. Dietary inclusion of 2% SBE appears to be recommendable to improve specific growth rate of fish and SBE had the potential to mitigate mortality of fish at E. tarda infection.

• Journal of Korean Society for Quality Management
• /
• v.52 no.2
• /
• pp.241-254
• /
• 2024

Purpose: This paper investigated the effects of issue leadership on employees' work performance. It also explored the mediating role of job challenge in the above relationship. We also tested the moderating effect of psychological ownership in the relationship between issue leadership and job challenge. Finally, this paper examined the moderated mediation effect of psychological ownership in the course of affecting issue leadership on work performance via job challenge. Methods: This paper used a cross-sectional design with questionnaires administered to 390 employees working in Korean firms. It applied an hierarchical and multi-regression analysis by using SPSS 22.0 and Hayes' Macro Process to test the proposed hypotheses including a moderated mediation model. Results: As a result of the analysis, first, it was found that the issue leadership had a positive effect on the work performance. Second, it was also found that issue leadership had a positive effect on the job challenge. In addition, job challenge was found to positive mediating effect in the relationship between issue leadership and work performance. Third, we found that the psychological ownership positively moderated the relationship between issue leadership and job challenge. Finally, the moderated mediating effect was found by confirming that the higher the degree of psychological ownership, the stronger the effect of issue leadership on the work performance via job challenge. Conclusion: This paper contributes to the leadership and work performance studies by identifying the role of issue leadership enhancing employee work performance while confirming connection mechanism and boundary conditions strengthening the positive effect of issue leadership on employee work performance.