The aim of this paper is to introduce basic concepts and methods for calculating sample size in animal studies. At the planning stage of clinical studies, the determination of the sample size is a very important process to show the validity, accuracy, and reliability of the study. However, not all studies require a sample size to be calculated. Before conducting the study, it is essential to determine whether the study objectives suggest a pilot and exploratory study, as well as the purpose of testing the hypothesis of interest. Since most animal experiments are pilot and exploratory studies, it would be more appropriate to review other considerations for conducting an experiment while maintaining scientific and qualitative levels rather than sample size estimation. Sample size is calculated in various situations in animal studies. Therefore, it can be estimated according to the situations and objectives through the methods of precision analysis, power analysis, and so on. In some cases, nonparametric methods can be employed if the assumptions of normality is not met or a small sample is available for the study.

The purpose of this study was to investigate the intakes and perceptions of convenient breakfast related to age and family type. The survey included 545 men and women living in Seoul from June to July. Questionnaire items covered their age, gender, family types, breakfast intakes and preference for convenient breakfast menu. As a result, there were significant differences in the number of breakfast intakes per week according to family types; large families recorded the highest frequency in "I have breakfast everyday" and the couple-only families and nuclear families scored relatively high numbers. In terms of the type of breakfast, the first choice was "rice and side dishes" across all the age groups (69.3%). There were differences in the preference of convenient breakfast in "bread", "cereal", "rice cake", "sunsik", and "rice gruel" by different age. The teens exhibited the highest preference of bread (5.63), and cereal (5.53) for breakfast; those who were in their fifties for rice cake (5.42). Both forties and fifties showed the higher preference of sunsik (4.58, 4.76) and rice gruel (5.89, 5.77) than other age groups. As for the preference for convenient breakfast according to family types, single person families displayed the highest preference of bread (5.42) and cereal (5.75). Couple families showed higher preference of rice gruel (5.82) than other family groups. The preference level for "rice cake" was similar among all the family types. As a result, it is suggested that the development of various breakfast menus considering age groups and family types is needed so that modern people can enjoy breakfast in terms of quality and quantity in their busy daily life.
Adolescent ; Bread ; Breakfast ; Edible Grain ; Female ; Humans ; Male ; Nuclear Family ; Surveys and Questionnaires ; Single Person

We experienced a case of transient right-sided heart failure after angioplasty of membranous obstruction of the inferior vena cava confirmed by sonography and an inferior vena cavogram. Angioplasty involved the use of a self-expandable metallic stent, but after successful recanalization of the obstruction , the patient became dyspneic. Chest radiography revealed mild cardiomegaly with pulmonary congestion, but this was resolved spontaneously. For the prevention of serious heart failure, we recommend preprocedural evaluation of cardiac function.
Angioplasty* ; Cardiomegaly ; Estrogens, Conjugated (USP) ; Heart Failure* ; Humans ; Radiography ; Stents ; Thorax ; Vena Cava, Inferior*

BACKGROUND: Nitric oxide (NO) is a selective pulmonary vasodilator, and inhaled NO has bronchodilatory action due to their relaxation effect on conducting airway smooth muscle. The aim of this study was to evaluate the effects of inhaled NO on respiratory system mechanics in cats. METHODS: Nineteen cats were divided into 3 groups according to the doses of NO administered; group C (control, n=7), group 20 (20 ppm of NO, n=7), and group 40 (40 ppm of NO, n=5). After measuring the baseline value, methacholine chloride 25 microgram/kg/min was infused to induce bronchoconstriction. Inhalation of NO was started for each group 15 minutes after methacholine infusion. Pressure, volume, and flow rate were monitored with Bicore CP100 pulmonary monitor and the data were transferred to a personal computer and analyzed by a processing software. Respiratory system, airway and tissue viscoelastic resistances, and dynamic and static compliances were calculated. RESULTS: Methacholine infusion increased both airway and tissue resistances. Fifteen minutes after inhaling NO, airway resistances for NO 20 ppm and 40 ppm decreased to 65.8+/-8.5% and 62.2+/-8.9% of the control value (p<0.05). The values of tissue resistances for NO 20 ppm and 40 ppm decreased to 72.4+/-10.8% and 78.2+/-10.5% of the control value respectively (p<0.05). And thirty minutes after inhaling NO, there were also decreases of airway and tissue viscoelastic resistances in both groups but had no differences compared with fifteen minutes' values. There were no significant differences between the NO 20 ppm and 40 ppm in the values of airway and tissue viscoelastic resistances. CONCLUSION: Inhaled NO of 20 ppm and 40 ppm decreased both airway and tissue viscoelastic resistances and airway resistance was decreased more markedly than tissue resistance. There were no significant differences between 20 ppm and 40 ppm of NO in respiratory system mechanics in cats.
Airway Resistance ; Animals ; Bronchoconstriction* ; Cats* ; Inhalation ; Mechanics* ; Methacholine Chloride ; Microcomputers ; Muscle, Smooth ; Nitric Oxide* ; Relaxation ; Respiratory System*

The purpose of this study was to assess the physical activity of preschool children using an accelerometer and investigate differences related to epoch length setting during use of the accelerometer. Subjects of the study were 26 children (12 boys and 14 girls) at the age of 5, enrolled in one preschool located in Gangneung. From 9:00 a.m. to 4:00 p.m. (7 hours period), every child wore a total of four accelerometers (ActiGraph GT3X⁺, USA), including three attached to the left hip (with epoch length set at 5 seconds, 15 seconds, and 30 seconds). For comparison purposes, a forth was attached to the opposite position, with epoch length set at 5 seconds. Data collected using 15s epoch and 30s epoch (single larger epoch) were compared with those obtained after reintegration of 5s to 15s epoch, 5s to 30s epoch, and 15s to 30s epoch, respectively (smaller epochs reintegrated). According to the results of this study, there were no significant differences in VM between 30s epoch and 5s to 30s epoch reintegrated and in MVPA (moderate-to-vigorous physical activity), between 15s epoch and 5s to 15s epoch reintegrated. From the Bland-Altman plot, reintegration of 15s to 30s epoch in VM and reintegrations of 15s to 30s epoch and 5s to 15s epoch in MVPA can be recommended for assessing physical activity in preschool children. Further research is needed into the reintegration method while using an accelerometer for assessment of energy expenditure in children.
Child ; Child, Preschool* ; Energy Metabolism ; Gangwon-do ; Hip ; Humans ; Methods ; Motor Activity*

PURPOSE: The purpose of this study was to measure energy expenditure (EE) the metabolic equivalents (METs) of 13 common physical activities by using a portable telemetry gas exchange system (K4b2) and to assess the accuracy of the accelerometer (Actigraph GT3X+) by gender in Korean adults. METHODS: A total of 109 adults (54 males, 55 females) with normal BMI (body mass index) participated in this study. EE and METs of 13 selected activities were simultaneously measured by the K4b2 portable indirect calorimeter and predicted by the GT3X+ Actigraph accelerometer. The accuracy of the accelerometer was assessed by comparing the predicted with the measured EE and METs. RESULTS: EE (kcal/kg/hr) and METs of treadmill walking (3.2 km/h, 4.8 km/h and 5.6 km/h) and running (6.4 km/h) were significantly higher in female than in male participants (p < 0.05). On the other hand, the accelerometer significantly underestimated the EE and METs for all activities except descending stairs, moderate walking, and fast walking in males as well as descending stairs in females. Low intensity activities had the highest rate of accurate classifications (88.3% in males and 91.3% females), whereas vigorous intensity activities had the lowest rate of accurate classifications (43.6% in males and 27.7% in females). Across all activities, the rate of accurate classification was significantly higher in males than in females (75.2% and 58.3% respectively, p < 0.01). Error between the accelerometer and K4b2 was smaller in males than in females, and EE and METs were more accurately estimated during treadmill activities than other activities in both males and females. CONCLUSION: The accelerometer underestimated EE and METs across various activities in Korean adults. In addition, there appears to be a gender difference in the rate of accurate accelerometer classification of activities according to intensity. Our results indicate the need to develop new accelerometer equations for this population, and gender differences should be considered.
Adult* ; Calorimetry, Indirect ; Classification ; Energy Metabolism* ; Female ; Hand ; Humans ; Male ; Metabolic Equivalent ; Motor Activity* ; Running ; Telemetry ; Walking