Pulmonary function testing (PFT) is an important and fundamental method in the evaluation and treatment of respiratory diseases. Airway responsiveness assessed using histamine or methacholine by PFT is meaningful for the diagnosis of asthma. Spirometry is simple, and has been the most commonly used technique. However, in younger or uncooperative children, other commercially available tools such as impulse oscillometry (IOS), gas dilution, and plethysmography have been used. IOS is a noninvasive method that allows the measurement of airway mechanics (resistance [R] and reactance [X]) with minimal patient cooperation. Functional residual capacity (FRC) is one of the most important measurements obtained by gas dilution. Plethysmography is a gold standard to measure airway resistance and useful for lung function testing in infants. The purpose of this review is to help pediatric physicians being familiar with PFT techniques used in young children by discussing their principles, clinical applications, limitations, and current accessibility in Korea.
Airway Resistance ; Asthma ; Child* ; Diagnosis ; Functional Residual Capacity ; Histamine ; Humans ; Infant ; Korea ; Lung* ; Mechanics ; Methacholine Chloride ; Oscillometry ; Patient Compliance ; Plethysmography ; Respiratory Function Tests ; Spirometry

PURPOSE: Fractional exhaled nitric oxide (FeNO) is a maker of airway inflammation, and impedance of low frequency in the impulse oscillometry system (IOS) reflects small-airway obstruction. We investigated the association of the FeNO level with IOS parameters and spirometry results in asthma patients. METHODS: Fifty-eight children with asthma (60.3%, male), mean age 8.3 years (range, 4.5-16.0 years), were enrolled in the study. Reactance and resistance at 5 Hz with IOS, forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and forced expiratory flow 25%-75% of the vital capacity (FEF25%-75%) with spirometry and FeNO were measured in all patients. The Z-score of spirometry and IOS parameters and the mean level of FeNO were used for correlation and regression analysis. RESULTS: FeNO was not significantly associated with height, age, or other demographic parameters. There was a statistically significant correlation between spirometry results and IOS measurements. The FeNO level was not significantly correlated with IOS variables. After adjusting for height, sex, atopic status, and the use of inhaled corticosteroid, the FeNO level showed significant correlations with Z-score of FEV1/FVC (P=0.037, adjusted R 2=0.234). CONCLUSION: FeNO was significantly correlated with Z-scores of FEV1/FVC, but not with IOS variables. Therefore, FeNO may be used to detect whole airway obstruction, but not small-airway obstruction.
Airway Obstruction ; Asthma* ; Child* ; Electric Impedance ; Forced Expiratory Volume ; Humans ; Inflammation ; Nitric Oxide* ; Oscillometry* ; Regression Analysis ; Respiratory Function Tests ; Spirometry* ; Vital Capacity

PURPOSE: Circulating patterns of predominant respiratory syncytial virus (RSV) genotypes in the community may be helpful in understanding molecular epidemiology and predicting future outbreaks of the RSV genotype. We investigated the association of genetic variations in RSV with acute severe bronchiolitis in infants. METHODS: We reviewed medical records of infants younger than 1 year of age hospitalized due to acute bronchiolitis between November 2016 and February 2017. Subjects were classified as severe or mild based on the use of mechanical or noninvasive ventilation. The associations between severity of the disease, sex, age at admission, oxygen saturation at admission and laboratory test results were analyzed. RSV sequence analysis was performed in the severe group. RESULTS: Among 114 infants, 80 underwent respiratory viral polymerase chain reaction using nasopharyngeal swab; of these, 53 (66.3%) showed positive for RSV. Of the 53 RSV-positive samples, 9 were categorized as the severe group and 44 were categorized as the mild group. Male sex, young age, longer duration of admission, minimum SaO2 at admission and bronchiolitis severity score were significantly correlated with disease severity in the severe group than in the mild group (all variables, P < 0.001). Phylogenetic and sequence analysis in the severe group revealed 8 RSV-A, ON1 genotype and 1 RSV-B, BA4 genotype. CONCLUSION: Phylogenetic types of RSV in subjects of the severe group were RSV-A, ON1 genotype or RSV-B, BA4 genotype which were prevalent in the Korean community at the same time. Our study showed that disease severity was not significantly associated with RSV genotypic evolution or antigenic drift in Korea during winter season 2016–17.
Bronchiolitis* ; Disease Outbreaks ; Genetic Variation* ; Genotype ; Humans ; Infant* ; Korea* ; Male ; Medical Records ; Molecular Epidemiology ; Noninvasive Ventilation ; Oxygen ; Polymerase Chain Reaction ; Respiratory Syncytial Viruses* ; Seasons* ; Sequence Analysis

This experiment was undertaken to screen the acaricidal effects of herb essential oils (pennyroyal, ylang ylang, citronella, lemon grass, tea tree, and rosemary) at different doses (0.1, 0.05, 0.025, 0.0125, and 0.00625 microliter/cm2) and exposure times (5, 10, 20, 20, 30 and 60 min) on house dust mites Dermatophgoides farinae and D. pteronyssinus. The most effective acaricidal components of pennyroyal (Mentha pulegium) were analyzed using a gas chromatography-mass spectrometer (GC-MS). Of these essential oils, the most effective was pennyroyal, which is composed essentially of pulegone (> 99%), at a dose of 0.025 microliter/cm2, which at an exposure time of 5 min killed more than 98% of house dust mites. In the pennyroyal fumigation test, the closed method was more effective than the open method and maximum acaricidal effect was 100% at 0.025 microliter/cm2, 60 min. The results show that herb essential oils, in particular, pennyroyal was proved to have potent acaricidal activity
Time Factors ; Plant Oils/chemistry/*pharmacology ; Oils, Volatile/chemistry/*pharmacology ; Mentha pulegium/*chemistry ; Insecticides/pharmacology ; Dose-Response Relationship, Drug ; Dermatophagoides pteronyssinus/*drug effects ; Dermatophagoides farinae/*drug effects ; Animals

OBJECTIVES: To integrate the results of studies which assess an association between blood lead and blood pressure. METHODS: We surveyed the existing literature using a MEDLINE search with blood lead and blood pressure as key words, including reports published from January 1980 to December 2000. The criteria for quality evaluation were as follows: 1) the study subjects must have been workers exposed to lead, and 2) both blood pressure and blood lead must have been measured and presented with sufficient details so as to estimate or calculate the size of the association as a continuous variable. Among the 129 articles retrieved, 13 studies were selected for quantitative meta-analysis. Before the integration of each regression coefficient for the association between blood pressure and blood lead, a homogeneity test was conducted. RESULTS: As the homogeneity of studies was rejected in a fixed effect model, we used the results in a random effect model. Our quantitative meta-analysis yielded weighted regression coefficients of blood lead associated with systolic blood pressure and diastolic blood pressure results of 0.0047 (95% confidence interval [CI]: -0.0061, 0.0155) and 0.0004 (95% CI: -0.0031, 0.0039), respectively. CONCLUSIONS: The published evidence suggested that there may be a weak positive association between blood lead and blood pressure, but the association is not significant.
Blood Pressure*

OBJECTIVES: In order to assess clinical behavior, response to treatment, and factors influencing prognosis of Korean patients with osteosarcoma of the jaws (OSJ). MATERIALS AND METHODS: A retrospective study of clinical, and pathological records of 26 patients with OSJ treated at the Department of Oral and Maxillofacial Surgery in Yonsei University Dental Hospital from 1990 to March 2017. RESULTS: Of 26 patients, there were 9 men (34.6%) and 17 women (65.4%). Twenty-one of 26 patients had osteosarcoma of the mandible, and 5 of 26 patients had osteosarcoma of the maxilla. The histopathology of OSJ is highly variable, ranging from chondroblastic type (6 out of 26), osteoblastic type (10 out of 26), fibroblastic type (2 out of 26), to the rare variants like mixed type, small cell osteosarcoma types and more. All patients underwent gross total excision and only a few patients underwent neoadjuvant chemotherapy. Postoperative chemotherapy was given to most of the patients as adjuvant treatment or in combination with radiotherapy. The overall survival rate was 73.1% with an overall 2-year survival rate of 83.3%. The overall 5-,10-,15-year survival rates in this study were 73.5%, 73.5%, 49%, respectively. Using Kaplan-Meier analysis with log rank tests, the size of tumor (T-stage), and resection margins were found to affect the survival rate significantly. The chemotherapy was not significantly associated with improved survival rate. CONCLUSION: Surgical resection with a clear margin is the most important factor in disease survival. The role of chemotherapy and radiotherapy in OSJ remains controversial, and deserves further studies.
Chondrocytes ; Drug Therapy ; Female ; Fibroblasts ; Humans ; Jaw* ; Kaplan-Meier Estimate ; Male ; Mandible ; Maxilla ; Osteoblasts ; Osteosarcoma* ; Prognosis ; Radiotherapy ; Retrospective Studies ; Surgery, Oral ; Survival Rate

OBJECTIVES: In order to assess clinical behavior, response to treatment, and factors influencing prognosis of Korean patients with osteosarcoma of the jaws (OSJ). MATERIALS AND METHODS: A retrospective study of clinical, and pathological records of 26 patients with OSJ treated at the Department of Oral and Maxillofacial Surgery in Yonsei University Dental Hospital from 1990 to March 2017. RESULTS: Of 26 patients, there were 9 men (34.6%) and 17 women (65.4%). Twenty-one of 26 patients had osteosarcoma of the mandible, and 5 of 26 patients had osteosarcoma of the maxilla. The histopathology of OSJ is highly variable, ranging from chondroblastic type (6 out of 26), osteoblastic type (10 out of 26), fibroblastic type (2 out of 26), to the rare variants like mixed type, small cell osteosarcoma types and more. All patients underwent gross total excision and only a few patients underwent neoadjuvant chemotherapy. Postoperative chemotherapy was given to most of the patients as adjuvant treatment or in combination with radiotherapy. The overall survival rate was 73.1% with an overall 2-year survival rate of 83.3%. The overall 5-,10-,15-year survival rates in this study were 73.5%, 73.5%, 49%, respectively. Using Kaplan-Meier analysis with log rank tests, the size of tumor (T-stage), and resection margins were found to affect the survival rate significantly. The chemotherapy was not significantly associated with improved survival rate. CONCLUSION: Surgical resection with a clear margin is the most important factor in disease survival. The role of chemotherapy and radiotherapy in OSJ remains controversial, and deserves further studies.
Chondrocytes ; Drug Therapy ; Female ; Fibroblasts ; Humans ; Jaw* ; Kaplan-Meier Estimate ; Male ; Mandible ; Maxilla ; Osteoblasts ; Osteosarcoma* ; Prognosis ; Radiotherapy ; Retrospective Studies ; Surgery, Oral ; Survival Rate

OBJECTIVE: This study was performed to investigate an appropriate degree of prestretch for orthodontic synthetic elastomeric chains focusing on time-dependent viscoelastic properties. METHODS: Orthodontic synthetic elastomeric chains of two brands were prestretched to 50, 100, 150, and 200% of the original length in one and three cycles, and the hysteresis areas of the obtained stress-strain curves were determined. Acrylic plates were employed to maintain constant strain during the experiment. A total of 180 samples were classified into nine groups according to brand, and their stresses and permanent deformations were measured immediately after prestretch (0 hour), after 1 hour and 24 hours, and after 1, 2, 3, 4, 5, 6, 7, and 8 weeks. The relationship between stress relaxation and permanent deformation was investigated for various degrees of prestretch, and the estimated stress resulting from tooth movement was calculated. RESULTS: The degree of prestretch and the stress relaxation ratio exhibited a strong negative correlation, whereas no correlation was found between the degree of prestretch and the average normalized permanent strain. The maximal estimated stress was observed when prestretch was performed in three cycles to 200% of the original length. CONCLUSIONS: Although prestretch benefited residual stress, it did not exhibit negative effects such as permanent deformation. The maximal estimated stress was observed at the maximal prestretch, but the difference between prestretch and control groups decreased with time. In general, higher residual stresses were observed for product B than for product A, but this difference was not clinically significant.
Elastomers* ; Relaxation* ; Tooth Movement

PURPOSE: To determine useful diagnostic criteria of cubital tunnel syndrome (CTS), using ultrasonographic ulnar nerve cross-sectional areas (UNCSA) measurements. MATERIALS AND METHODS: The CTS group included 28 patients confirmed with nerve conduction study and the control group included 17 healthy adults. Ulnar nerve cross-sectional areas (UNCSA) were measured at the distal 1/3 upper arm level and in the cubital tunnel (CTN). US findings of CTS were ulnar nerve dislocation (n = 2), ulnar nerve subluxation (n = 5), ganglion (n = 1), sever elbow joint osteoarthritis (n = 1) and elbow joint valgus deformity after fracture (n = 1). UNCSA, the ratio of UNCSA in CTN to distal 1/3 upper arm level (CH ratio), and the difference of UNCSA between CTN and distal 1/3 upper arm level (CH difference) were evaluated to obtain the optimal diagnostic cutoff value of CTS, using ROC curve. RESULTS: The mean UNCSA in CTN was 0.168 cm2 in the CTS and 0.067 cm2 in the control. The CTS could be diagnosed when UNCSA, the CH ratio and the CH difference are larger than 0.096 cm2, 1.371 and 0.036 cm2 respectively. The ROC curve area was largest and the sensitivity, specificity was respectively 82.4%, 95.8%, when the CH difference was used as cutoff value. CONCLUSIONS: Ultrasound is useful for the detection of CTS pathogenic lesions in CTN. The highest diagnostic accuracy was acquired when the CH difference is larger than 0.036 cm2.
Adult ; Arm ; Congenital Abnormalities ; Cubital Tunnel Syndrome ; Dislocations ; Diterpenes ; Elbow Joint ; Ganglion Cysts ; Humans ; Neural Conduction ; Osteoarthritis ; ROC Curve ; Sensitivity and Specificity ; Ulnar Nerve

Extra-amniotic pregnancy, which is caused by rupture of amniotic membranes only, is a rare event during pregnancy. This differs from extra-membranous pregnancy in which both chorionic and amniotic membranes rupture. Extra-amniotic pregnancy requires attention by an obstetrician not to miss fetal anomalies because extra-amniotic pregnancy may accompany with fibrous band syndrome. We experienced a case of extraamniotic pregnancy with congenital amputation of bilateral fetal hands. And we report it with brief review of literatures.
Amnion ; Amniotic Band Syndrome ; Amputation ; Chorion ; Hand ; Infant, Newborn ; Pregnancy ; Pregnancy Complications ; Rupture