• Journal of Veterinary Clinics
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• v.29 no.1
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• pp.68-77
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• 2012

Whenever planning a study design or preparing a research proposal it is highly recommended that investigators decide the optimum sample size that is required to yield an outcome of interest with a predetermined level of precision. This is because that, all else being equal, if a study with less than the optimum sample size would not detect the significance of differences in reality, and similarly, if a study with more than the optimum sample size will be costly. For these reasons, the majority of peer reviewed biomedical journals assess the adequacy of sample size requirements. The calculated sample size is used as a target number of samples to be collected to provide an estimate of the parameter with the desired and predetermined level of accuracy, and the sample size is a major determinant of the probability of detecting diseased animals from the population. There is no single method of calculating sample size for any given study design. In this context, the purpose of this article is to provide a collection of formulas and examples for some typical situations likely to be encountered in veterinary clinical practice and to highlight the importance of performing prospective sample size calculations when planning a research. Specifically, this paper is concerned with the basic principle of sample size calculation, and considerations for methodological applications were illustrated for a given data set. Also included in this paper is factors influencing sample size calculations using a statistically valid techniques. Appropriate methods to consider these factors are presented.

• Sleep Medicine and Psychophysiology
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• v.8 no.1
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• pp.5-10
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• 2001

The prevalence of insomnia and the degree of impairment due to insomnia is greater than in the of young. The cause for insomnia in the elderly are various factors among the elderly is known to be high including medical, psychiatric, drug issues, circadian rhythm changes, sleep disorders, and psychosocial. So the careful evaluation to find the cause of insomnia is needed for the eldery. Treatment options for insomnia include behavior modification and pharmacotherapy. Outcome data from previous studies indicate that behavioral approaches produce reliable and durable therapeutic benefits, as evidenced by improved sleep efficiency and continuity and enhanced satisfaction with sleep patterns. Treatment methods such as stimulus control and sleep restriction, which target maladaptive sleep habits, are especially beneficial for older insomniacs, whereas relaxation-based interventions aimed at decreasing arousal, produce more limited effects. Cognitive and educational interventions are instrumental in altering age-related dysfunctional beliefs and attitudes about sleep. The choice of hypnotics is based on matching the nature of the insomnia to the hypnotic agent. The ideal agent has rapid onset, duration of action that lasts through the night but no residual daytime effects, and no adverse effects. The key for the healthcare professional is finding the appropriate treatment or treatment combination, including behavioral modification and pharmacotherapy. When hypnotics are indicated, the most appropriate short-acting agent should be considered.

• Laboraroty Animal Research
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• v.34 no.4
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• pp.133-139
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• 2018

Nonalcoholic steatohepatitis (NASH) is becoming common chronic liver disease because of the increasing global prevalence of obesity and consequently Nonalcoholic fatty liver disease (NAFLD). However, the mechanism for progression of NAFLD to NASH and then cirrhosis is not completely understood, yet. The triggering of these hepatic diseases is thought from hepatocyte injury caused by over-accumulated lipid toxicity. Injured hepatocytes release damage-associated molecular patterns (DAMPs), which can stimulate the Kupffer cells (KCs), liver-resident macrophages, to release pro-inflammatory cytokines and chemokines, and recruit monocyte-derived macrophages (MDMs). The increased activation of KCs and recruitment of MDMs accelerate the progression of NAFLD to NASH and cirrhosis. Therefore, characterization for activation of hepatic macrophages, both KCs and MDMs, is a baseline to figure out the progression of hepatic diseases. The purpose of this review is to discuss the current understanding of mechanisms of NAFLD and NASH, mainly focusing on characterization and function of hepatic macrophages and suggests the regulators of hepatic macrophages as the therapeutic target in hepatic diseases.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.4
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• pp.323-328
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• 2020

Direct injection of genome editing tools such as CRISPR/Cas9 system into developing embryos has been widely used to generate genetically engineered pigs. The approach allows us to produce pigs carrying targeted modifications at high efficiency without having to apply somatic cell nuclear transfer. However, the targeted modifications during embryogenesis often result in mosaicism, which causes issues in phenotyping founder animals and establishing a group of pigs carrying intended modifications. This study was aimed to establish a genomic PCR and sequencing system of a single blastomere in the four-cell embryos to detect potential mosaicism. We performed genomic PCR in four individual blastomeres from four-cell embryos. We successfully amplified target genomic region from single blastomeres of 4-cell stage embryo by PCR. Sanger sequencing of the PCR amplicons obtained from the blastomeres suggested that PCR-based genotyping of single blastomere was a feasible method to determine mutation type generated by genome editing technology such as CRISPR/Cas9 in early stage embryos. In conclusion, we successfully genotyped single blastomeres in a single 4-cell stage embryo to detect potential mosaicism in porcine embryos. Our approach offers a simple platform that can be used to screen the prevalence of mosaicism from designed CRISPR/Cas9 systems.

• Tuberculosis and Respiratory Diseases
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• v.84 no.2
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• pp.89-95
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• 2021

Lung cancer is one of the leading causes of cancer-related deaths in Korea. Although the smoking rate has decreased over time, the prevalence of lung cancer still remains high. In this study, we reviewed recent trends on the incidence, epidemiology, screening, diagnosis, and treatment of lung cancer in Korea by analyzing data from the national lung cancer registry and recently-published studies. Although approximately 40% of patients with non-small cell lung cancer (NSCLC) were diagnosed as stage IV, the 5-year relative survival rate improved from 11.3% (1993-1995) to 30.2% (2013-2017), possibly due to advances in methods of diagnosis and therapy. In addition, the 2019 implementation of the national lung cancer screening program with low-dose computed tomography may have also contributed to these improvements in survival rates. Recently, molecular diagnosis has become more widely used in the identification of genetic mutations in tissue specimens. Target therapy and immune checkpoint inhibitors have also been successfully used, particularly in cases of advanced NSCLC. In the future, further research on the optimal management of lung cancer remains necessary.

• Journal of Preventive Medicine and Public Health
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• v.54 no.4
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• pp.284-292
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• 2021

Objectives: Low bone density (LBD) in the postmenopausal period has long been a pervasive public health concern; however, the association between parity and LBD has yet to be fully elucidated. Thus, we investigated the association between parity and LBD in postmenopausal Korean women. Methods: This study used baseline data from 1287 Korean postmenopausal women aged 40 years or older enrolled in the Cardiovascular and Metabolic Diseases Etiology Research Center community-based cohort study conducted in Korea from 2013 to 2017. The main exposure was parity (nullipara, 1, 2, 3+). The main outcome was LBD, including osteopenia and osteoporosis, based on bone mineral density measured using quantitative computed tomography of the lumbar spine (L1-2). Results: The mean age of participants was 57.1 years, and the median parity was 2. Of the 1287 participants, 594 (46.2%) had osteopenia and 147 (11.4%) had osteoporosis. No significant difference in the prevalence of LBD was found between nullipara and parous women, whereas higher parity was associated with a higher risk of LBD among parous women; the adjusted odds ratio (95% confidence interval) for the presence of LBD was 1.40 (0.97 to 2.02) for a parity of 2 and 1.95 (1.23 to 3.09) for a parity of 3 relative to a parity of 1. Conclusions: Women who have given birth multiple times may be at greater risk of bone loss after menopause; therefore, they should be a major target population for osteoporosis prevention.

• Journal of Convergence Korean Medicine
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• v.4 no.1
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• pp.5-11
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• 2022

Objectives: Inflammasomes are molecular platforms that are generated inside cytoplasmic compartments. The objective is to mediate immunological responses of the host to cell damage and infection. Caspase-1 is triggered by inflammasome to generate interleukin-1𝛽 (IL-1𝛽), an inflammatory cytokine, and pyroptosis, an inflammatory form of apoptosis. Methods: In the past two decades, scientists have uncovered several inflammasomes. The most research has been conducted on NLRP3 inflamamsomes, whose activity can be stimulated by a variety of induction factors. However, the unregulated activation of NLRP3 inflammasomes is also a role in the etiology of several human disorders. Previous research has demonstrated that NLRP3 inflammasomes have a significant role in the innate and acquired immune systems, as well as in the prevalence of joint illnesses such rheumatoid arthritis. Conclusion: Within the scope of this review, we will present a brief overview of the biological features of NLRP3 inflamamsomes as well as a description of the underlying mechanisms governing activation and regulation. In particular, we explore the function of inflammasomes in the development of rheumatoid arthritis as well as the promise of recently identified medicines that target inflamasomes.

• Journal of fish pathology
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• v.36 no.2
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• pp.303-310
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• 2023

Yellow goosefish (Lophius litulon) is one of the important commercial fisheries target species in Korea, and commonly consumed as braised or stew. The microsporidian Spraguea is known to infect the nervous system of lophiid fish, forming numerous visible whitish xenomas. This parasite is commonly found in lophiid fish worldwide, but there is no information on the infection status of this parasite in Korea. We obtained commercially available chopped packs of lophiid fish from several fish markets and investigated their prevalence of infection. The isolated xenomas were crushed and purified as mature spore suspension. Microscopic observation and PCR were conducted to visualize and identify them. The host fish was also identified by DNA bar cording analysis. All the specimens were heavily infected and microscopic observation with Giemsa or Chromotrope 2R stain revealed tiny oval shapes of typical microsporidian spores. PCR analysis targeting the partial SSU rDNA showed that our specimen belongs to the genus Spraguea clade. But clear identification at the species level was not possible, due to the insufficient information of gene sequences available in GenBank. In addition, all of our host fish specimen was identified as yellow goosefish. This is the first report of a microsporidian parasite Spraguea infection in yellow goosefish from Korea.

• Journal of Life Science
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• v.22 no.2
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• pp.148-155
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• 2012

A cross-sectional analysis of blood pressure (BP) changes and the current prevalence and distribution of hypertension among age groups in Korea were conducted. Systolic (SBP), diastolic (DBP), and pulse (PP) pressures were evaluated. Residents visiting a local Community Health Center for a health check-up and/or participating in the Health Promotion Program were included for the analyses. A total of 6,570 subjects (2,809 men, 3,761 women) were divided into five age groups: 30-39, 40-49, 50-59, 60-69, and $70\leq$ years. Comparisons were made between sex and among age groups. SBP and DBP were continuously elevated, while men showed higher levels than women until their mid-60s; then, the trend was reversed. DBP in men became elevated from their 30s, reaching the highest in the 40s then slowly decreasing. DBP in women increased up to their 40s and 50s, then reached a plateau. PP increased rapidly from the 50s in both sexes. The major contributor of age-related BP elevation may be large artery stiffness in men, particularly from their 50s, while the blood pressure elevation of women may relate to diverse factors including large artery stiffness, stroke volume, and ventricular ejection rate. The rapid elevation of PP after the 50s in both men and women could represent a risk of cardiovascular or coronary mortality, particularly with increasing age. The current data showed a higher rate of hypertension in both sexes compared to previous reports. When those with both high-normal BP and hypertension are looked at in combination, BP management of the target population should be drastically elevated.

• Journal of Environmental Health Sciences
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• v.34 no.1
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• pp.20-26
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• 2008

The objective of the study which utilised population based data was to determine the respiratory condition of elementary school children in Gangneung. From October 9th to December 14th, 2006, Pulmonary Function Tests (PFT) including Forced Vital Capacity (FVC) and Forced Expiratoy Volume in I Second $(FEV_1)$ were conducted on the target group of children using a spirometer. The prevalence of asthmatic symptoms was 29.8% among boys and 39.6% among girls. By using logistic regression, we found that family history of allergic rhinitis (OR=3.90, CI=1.05-14.51), experience of allergic conjunctivitis (OR=4.67, CI=1.54-14.16) and atopic dermatitis (OR=2.86, CI=1.17-7.05) significantly increased the asthmatic symptoms. Also, a family history of asthma and food allergy were associated with asthmatic symptoms. In relation to housing and environmental risk factors, residences under the ground (OR=3.59, CI=1.35-9.51) and big-size dolls (OR=2.71, CI=0.86-8.53) significantly increased the prevalence of asthmatic symptoms. For PFT, above four families, exposure of passive smoking and pets significantly reduced FVC in both groups (p<0.05). In girls, a big-size doll was significantly associated with decreased lung function (FVC and $FEV_1$). In boys, using bed significantly reduced $FEV_1$. Also, the risk of asthmatic symptoms was found to increase when the house has been built for 5 years or more, the house is close to a road $({\leq}100m)$, a gas/Kerosene heater or carpet is utilized within the house. However, their differences were not significant. It is concluded that genetic factor such as a family history of respiratory disease, allergic symptoms and housing risk factor are related to asthmatic symptoms. These results were worth noting because the findings will help address risk factors related respiratory symptoms especially in relation to housing and environment.