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1.  Cut-Off Scores of the Children's Depression Inventory for Screening and Rating Severity in Korean Adolescents 
Psychiatry Investigation  2015;12(1):23-28.
The aim was to establish an optimal cut-off score of the Children's Depression Inventory (CDI) for detecting depression and rating severity in Korean adolescents.
A total of 468 students aged 12-16 years from 8 middle schools in Busan, Korea participated in this study. The Korean version of the CDI and Kiddie Schedule for Affective Disorders and Schizophrenia Present and Lifetime Version were used to evaluate depressive symptoms. Receiver-operating characteristics (ROC) analyses were conducted to evaluate case-finding performance and set the cut-off scores.
ROC analyses demonstrated that the overall discrimination power of the CDI is good enough to evaluate adolescent depression. The CDI sum score of 20 was identified as the optimal screening cut-off score, where sensitivity was 0.83 and specificity was 0.89. This cut-off score could apply regardless of subjects' gender. The cut-off scores were examined in order of the depression severity: 15 for mild, 20 for moderate, and 25 for severe depression with high sensitivity and specificity.
The CDI cut-off scores of our study can be recommended for screening depressed youth and rating the severity of depressive symptoms. The high negative predictive value suggested that the cut-off score of 20 would result in a small number of missed cases. Further studies are needed to ascertain these CDI cut-off scores for different age groups.
PMCID: PMC4310917
Children's Depression Inventory; Cut-off score; Adolescent; Depression; Screening; Severity
2.  Fundoplication in Neonates and Infants with Primary Gastroesophageal Reflux 
Gastroesophageal reflux in infant is a physiological process. However, surgery is performed in high risk infants with severe gastroesophageal reflux disease (GERD) when medical management fails. This study focuses on efficacy and safety of Nissen fundoplication for GERD in infants under age 12 months.
This study was a retrospective case analysis of 11 neonates and infants under 12 months of age who underwent Nissen fundoplication following a failure of medical treatment between June 2010 and June 2013 at Pusan National University Children's Hospital. The records were reviewed to determine the effect of fundoplication on symptoms and post-operative complications.
A total of 11 infants consist of four males and seven females. Mean birth weight was 2,305.5±558.6 g (1,390-3,130 g). They had some underlying disease, which are not related with GERD such as congenital heart disease (54.5%), prematurity (45.5%), neurologic disease (18.2%), respiratory disease (18.2%), and other gastrointestinal disease. Mean body weight at surgery was 3,803.6±1,864.9 g (1,938.7-5,668.5 g). Mean age at operation was 99.9±107.6 days (17-276 days). Duration from operation to full enteral feeding was 10.9 days. Symptoms related GERD disappeared in all patients including one who got reoperation. One infant died of congenital heart disease unrelated to surgery. There were no complications related to fundoplication.
Fundoplication is effective and safe treatment in the neonates and infants with severe GERD.
PMCID: PMC4107226  PMID: 25061584
Gastroesophageal reflux; Fundoplication; Infant
3.  Acalculous Diffuse Gallbladder Wall Thickening in Children 
Gallbladder (GB) wall thickening can be found in various conditions unrelated to intrinsic GB disease. We investigated the predisposing etiologies and the outcome of acalculous GB wall thickening in children.
We retrospectively analyzed 67 children with acalculous GB wall thickening who had visited our institute from June 2010 to June 2013. GB wall thickening was defined as a GB wall diameter >3.5 mm on abdominal ultrasound examination or computed tomography. Underlying diseases associated with GB wall thickening, treatment, and outcomes were studied.
There were 36 boys and 31 girls (mean age, 8.5±4.8 years [range, 7 months-16 years]). Systemic infection in 24 patients (35.8%), acute hepatitis in 18 (26.9%), systemic disease in 11 (16.4%), hemophagocytic lymphohistiocytosis in 4 (6.0%), acute pancreatitis in 3 (4.5%), and specific liver disease in 3 (4.5%) predisposed patients to GB wall thickening. Systemic infections were caused by bacteria in 10 patients (41.7%), viruses in 5 patients (20.8%), and fungi in 2 patients (8.3%). Systemic diseases observed were systemic lupus erythematosus in 2, drug-induced hypersensitivity in 2, congestive heart failure in 2, renal disorder in 2. Sixty-one patients (91.0%) received symptomatic treatments or treatment for underlying diseases. Five patients (7.5%) died from underlying diseases. Cholecystectomy was performed in 3 patients during treatment of the underlying disease.
A wide range of extracholecystic conditions cause diffuse GB wall thickening that resolves spontaneously or with treatment of underlying diseases. Surgical treatments should be avoided if there are no definite clinical manifestations of cholecystitis.
PMCID: PMC4107227  PMID: 25061585
Gallbladder wall thickening; Acalculous cholecystitis; Child
4.  Ibuprofen Associated Acute Vanishing Bile Duct Syndrome and Toxic Epidermal Necrolysis in an Infant 
Yonsei Medical Journal  2014;55(3):834-837.
Acute vanishing bile duct syndrome, a rare but rapidly progressive destruction of the intrahepatic bile ducts with unknown pathogenesis, is most often a drug- or toxin-related. Toxic epidermal necrolysis is a serious dermatologic condition and a potentially life threatening disease, which is drug or infection induced. Ibuprofen associated acute vanishing bile duct syndrome and toxic epidermal necrolysis have not been reported previously in infants. We report a 7-month-old infant with ibuprofen associated toxic epidermal necrolysis, followed by severe and rapidly progressive vanishing bile duct syndrome. She recovered totally with supportive care.
PMCID: PMC3990079  PMID: 24719156
Acute vanishing bile duct syndrome; toxic epidermal necrolysis; infant
5.  Clinical Characteristics of Failure to Thrive in Infant and Toddler: Organic vs. Nonorganic 
To investigate the clinical characteristics and outcomes among infants and toddlers with failure to thrive (FTT).
This retrospective study was done with 123 patients who had visited Pusan National University Children's Hospital during their first two years of life and had received an FTT diagnosis. We compared the clinical characteristics of the patients based on the causes of their FTT and their ages at the time of first hospital visit. We investigated triggering factors, feeding practices, and outcomes in 25 patients with nonorganic FTT (NOFTT).
Eighty cases (65.0%) were NOFTT. The gestational ages, birth weights, and weights at the first visits were significantly lower in patients with organic FTT (OFTT) (p<0.05). Infants who had first visited the clinic at age <6 months had the least z-score. The percentage of patients with severe weight decline was higher in OFTT than in NOFTT (60.0% vs. 17.3%). The z-scores at the follow-up visits were improved after treatment in both of the groups. Preceding infection was the most common triggering factor of NOFTT and persecutory feeding as abnormal behavior of caregiver was observed in 22 cases (88.0%). After treatment with feeding method modification, all patients with NOFTT showed normal growth.
Weight decline is more severe in OFTT patients and in younger patients at the first visit. Infants with FTT can attain normal weight gain growth by treating organic diseases and supplying proper nutrition in OFTT, and by correcting abnormal dietary behavior of caregiver in NOFTT.
PMCID: PMC3915728  PMID: 24511523
Failure to thrive; Infant
6.  Juvenile Polyp and Colonoscopic Polypectomy in Childhood 
This study aimed to evaluate the clinical features of juvenile polyp and the usefulness of polypectomy with entire colonoscopy in children.
We retrospectively reviewed the medical records of 83 children who were diagnosed with having juvenile polyps.
The mean age of the patients was 6.5±3.7 (range 1.3-14.5 years) years. The male to female ratio was 2.1 : 1. Eighty one patients (97.6%) had hematochezia, of which the observed characteristics included red stool (74.1%), blood on wipe (13.6%). The time interval between the 1st episode of hematochezia and colonoscopy was 8.9±20.4 (ranged 0.1-48.0) months. The most proximal regions of colonoscopic approach were terminal ileum (96.4%). Sixty three patients (75.9%) had a solitary polyp and 20 patients (24.1%) had multiple polyps. The sites of the polyps were rectum (61.4%), sigmoid colon (23.5%). Eighteen polyps (15.1%) were found more proximal locations than rectosigmoid. The polyp size ranged from 0.3 to 5 cm. After the polypectomy, hematochezia recurred in 9 patients. Endoscopic hemostasis was performed in 2 patients due to severe bleeding. All procedures were carried out without using general anesthesia.
Juvenile polyp occurred in a wide range locations and had variable sizes and numbers, suggesting that colonoscopy on the entire colon is necessary. Colonoscopic polypectomy is a simple and useful therapeutic method in children with juvenile polyp.
PMCID: PMC3746052  PMID: 24010095
Juvenile polyp; Colonoscopy; Polypectomy; Child
7.  Role of colonoscopy in the diagnosis and treatment of pediatric lower gastrointestinal disorders 
Korean Journal of Pediatrics  2010;53(9):824-829.
The safety and effectiveness of colonoscopy in the investigation of lower gastrointestinal tract pathology in children has been established for more than 2 decades in Korea. Skill and experience have since advanced to the point that both diagnostic and therapeutic colonoscopy are now routinely performed by most pediatric gastroenterologists. Pediatric colonoscopy differs significantly from its adult parallels in nearly every aspect including patient and parent management and preparation, selection criteria for sedation and general anesthetic, bowel preparation, expected diagnoses, instrument selection, imperative for terminal ileal intubation, and requirement for biopsies from macroscopically normal mucosa. Investigation of inflammatory bowel disease, whether for diagnosis or follow-up evaluation, and suspected colonic polyps are the most common indication for pediatric colonoscopy. The child who presents with signs and symptoms of lower gastrointestinal disorder should undergo colonoscopy with biopsy to make the diagnosis, as well as to help determine the appropriate therapy. This review introduces practical information on pediatric colonoscopy, the author's experiences, and the role of colonoscopic examination in the diagnosis and treatment of pediatric lower gastrointestinal disorders.
PMCID: PMC3005213  PMID: 21189966
Colonoscopy; Children
8.  Effect of Packaging Method and Storage Time on Physicochemical Characteristics of Dry-Cured Pork Neck Products at 10°C 
Dry-cured pork neck samples were stored at 10°C for 90 days under vacuum packaging (VP) or modified atmosphere packaging (MAP; 25% CO2+75% N2) conditions. The pH, moisture, water activity, total aerobic bacteria, and Enterobacteriaceae counts of dry-cured pork neck products with MAP were significantly lower than those with VP (p<0.05) after 90 days of storage. However, CIE b* and 2-thiobarbituric acid reacted substance (TBARS) values of the pork product with MAP were significantly higher (p<0.05) than those with VP. Total aerobic bacterial counts and Enterobacteriaceae counts of samples with MAP were lower than those with VP after 30 days of storage. Sensory results indicated that aroma, flavor and tenderness scores of the samples with both VP and MAP decreased during storage and the scores after >60 days of storage were lower than those at Day 1. In conclusion, despite presenting higher lipid oxidation, the samples stored in packages containing 25% CO2 for 90 days at 10°C have lower bacterial counts than vacuum-packed samples. Therefore, further studies should be performed on the packaging of dry-cured meat at adjusted concentrations of CO2.
PMCID: PMC4213708  PMID: 25358323
Color; Dry-Cured Pork Neck; Modified Atmosphere Packaging; Sensory Analysis; Thiobarbituric Acid Reacted Substance
9.  Treatment Efficacy of Electromyography versus Fiberscopy-Guided Botulinum Toxin Injection in Adductor Spasmodic Dysphonia Patients: A Prospective Comparative Study 
The Scientific World Journal  2014;2014:327928.
Introduction. This study prospectively evaluates and compares the treatment efficacy of botulinum toxin injection under electromyography guidance (EMG group) and percutaneous botulinum toxin injection under flexible fiberscopic guidance (fiberscopy group). Methods. Thirty patients with adductor spasmodic dysphonia (ADSD), who had never received treatment, were randomly allocated into EMG- or fiberscopy-guided botulinum toxin injections between March 2008 and February 2010. We assessed acoustic and aerodynamic voice parameters, and the voice handicap index (VHI) before injection and at 1, 3, and 6 months after injection. Results. The mean total dosage of botulinum toxin was similar for both groups: 1.7 ± 0.5 U for the EMG group and 1.8 ± 0.4 U for the fiberscopy group (P > 0.05). There were no significant differences in outcomes between the two groups in either the duration of effectiveness or complications such as breathy voice and aspiration. Conclusion. Botulinum toxin injection under fiberscopic guidance is a viable alternative to EMG-guided botulinum toxin injection for the treatment of adductor spasmodic dysphonia when EMG equipment is unavailable.
PMCID: PMC4213399  PMID: 25383369
10.  High Incidence of Staphylococcus aureus and Norovirus Gastroenteritis in Infancy: A Single-Center, 1-Year Experience 
The etiology of acute gastroenteritis (AGE) has changed since the introduction of the rotavirus vaccination. The aim of this study was to clarify which common pathogens, both bacterial and viral, are currently causing AGE in infants.
Infants with acute diarrhea were enrolled. We tested for 10 bacterial pathogens and five viral pathogens in stool specimens collected from infants with AGE. The clinical symptoms such as vomiting, mucoid or bloody diarrhea, dehydration, irritability, and poor oral intake were recorded, and laboratory data such as white blood cell count and C-reactive protein were collected. The clinical and laboratory data for the cases with bacterial pathogens and the cases with viral pathogens were compared.
Of 41 total infants, 21 (51.2%) were positive for at least one pathogen. Seventeen cases (41.5%) were positive for bacterial pathogens and seven cases (17.1%) were positive for viral pathogens. Staphylococcus aureus (13 cases, 31.7%) and Clostridium perfringens (four cases, 9.8%) were common bacterial pathogens. Norovirus (five cases, 12.2%) was the most common viral pathogen. Fever and respiratory symptoms were common in the isolated viral infection group (p=0.023 and 0.044, respectively), whereas other clinical and laboratory data were indistinguishable between the groups.
In our study, S. aureus (41.5%) and norovirus (12.2%) were the most common bacterial and viral pathogens, respectively, among infants with AGE.
PMCID: PMC4209318  PMID: 25349829
Gastroenteritis; Infant; Korea; Staphylococcus aureus; Epidemiology
11.  Sex and Age Differences in Psychiatric Disorders among Children and Adolescents: High-Risk Students Study 
Psychiatry Investigation  2014;11(3):251-257.
The aims of the present study are to investigate the rate of the psychiatric disorders in psychiatrically high-risk children and adolescents and to examine sex and age differences in the diagnosis of psychiatric disorders.
The participants included students aged 6-16 from the 27 elementary and the 45 middle schools in Busan, Korea. We screened psychopathology using the Korean version of Child Behavior Checklist (K-CBCL) or the Youth Self Report (K-YSR). A total of 2,912 students were selected as high-risk students on the basis of cut-off scores (T-score ≥60) for a total behavior problem score of K-CBCL/K-YSR. Of these high-risk students, 1,985 students participated in and completed individual diagnostic interviews. Psychiatric diagnosis was assessed using a Korean version of the Kiddie-Schedule for Affective Disorders and Schizophrenia. Multivariate logistic regression analysis was conducted to examine sex and age differences of psychiatric diagnosis.
Based on sex, boys were more likely to have ADHD and girls were more likely to have depression. Based on age, children were more likely to have ADHD and adolescents were more likely to have affective disorder, conduct disorder, psychotic disorder, and anxiety disorders except separation anxiety disorder.
This is the largest study to conduct face-to-face interviews with subjects and parent(s) among Korean studies in this field. The present study revealed significant differences across sex and age among specific psychiatric disorders in children and adolescents. Future population-based studies will be required to ascertain the sex- and age-related differences of psychiat prevalence.
PMCID: PMC4124183  PMID: 25110497
Psychiatric diagnosis; Sex; Age; Child; Adolescent; Epidemiology
12.  Association between Urinary Bisphenol A and Waist Circumference in Korean Adults 
Toxicological Research  2014;30(1):39-44.
Bisphenol A (BPA) is widely used in the production of polycarbonate plastics, epoxy resins, and food and beverage containers. In the present study, we aimed to investigate the relationship between urinary concentrations of BPA and waist circumference in Korean adults. A total of 1,030 Korean adults (mean age, 44.3 ± 14.6 years) were enrolled in the study on the integrated exposure to hazardous materials for safety control, conducted by the Ministry of Food and Drug Safety from 2010 to 2012. Abdominal obesity was defined as having a waist circumference of at least 90 cm and 85 cm for men and women, respectively. The participants were divided into 4 groups according to the urinary BPA concentration quartile. Waist circumference was significantly higher among subjects with a urinary BPA concentration in the highest quartile relative to those in the lowest quartile (p = 0.0071). Linear regression analysis revealed a significant positive association between urinary BPA concentrations and body mass index, body fat, after adjusting for potential confounders. Moreover, subjects with urinary BPA concentrations in the fourth quartile were more likely to be obese compared to those with urinary BPA concentrations in the first quartile (odds ratio, 1.938; 95% CI: 1.314~2.857; p for trend = 0.0106). These findings provide evidence for a positive association between urinary BPA concentration and waist circumference in Korean adults.
PMCID: PMC4007042  PMID: 24795798
Bisphenol A; Waist circumference; Korean adults
13.  Dietary Patterns in Children with Attention Deficit/Hyperactivity Disorder (ADHD) 
Nutrients  2014;6(4):1539-1553.
The role of diet in the behavior of children has been controversial, but the association of several nutritional factors with childhood behavioral disorders has been continually suggested. We conducted a case-control study to identify dietary patterns associated with attention deficit hyperactivity disorder (ADHD). The study included 192 elementary school students aged seven to 12 years. Three non-consecutive 24-h recall (HR) interviews were employed to assess dietary intake, and 32 predefined food groups were considered in a principal components analysis (PCA). PCA identified four major dietary patterns: the “traditional” pattern, the “seaweed-egg” pattern, the “traditional-healthy” pattern, and the “snack” pattern. The traditional-healthy pattern is characterized by a diet low in fat and high in carbohydrates as well as high intakes of fatty acids and minerals. The multivariate-adjusted odds ratio (OR) of ADHD for the highest tertile of the traditional-healthy pattern in comparison with the lowest tertile was 0.31 (95% CI: 0.12–0.79). The score of the snack pattern was positively associated with the risk of ADHD, but a significant association was observed only in the second tertile. A significant association between ADHD and the dietary pattern score was not found for the other two dietary patterns. In conclusion, the traditional-healthy dietary pattern was associated with lower odds having ADHD.
PMCID: PMC4011050  PMID: 24736898
dietary pattern; attention deficit/hyperactivity disorder (ADHD); school-aged children; Korean
14.  In Vitro Anti-Osteoporosis Properties of Diverse Korean Drynariae rhizoma Phenolic Extracts 
Nutrients  2014;6(4):1737-1751.
Drynariae rhizoma has been used to prevent bone loss that occurs with increasing age. However, the chemical compounds in extracts that act on bone metabolism in herbal medicine are poorly understood. This study aimed to investigate and compare the extraction efficacy of polyphenolic compounds, antioxidant activity, and in vitro anti-osteoporosis properties of water extract (DR-DW) and ethanol extract (DR-EtOH) from D. rhizoma. Total phenolics and flavonoids were better extracted with 70% EtOH, and this extraction method also resulted in higher antioxidant activity and in vitro anti-osteoporosis properties in these extracts. In particular, the contents of phloroglucinol, protocatechuic acid ethyl ester, 2-amino-3,4-dimethyl-benzoic acid, 3-(3,5-dimethyl-pyrazol-1-yl)-benzoic acid, chlorogenic acid, syringic acid, trans-ferulic acid, (−)-epigallocatechin, epigallocatechin gallate, quercetin dehydrate, luteolin and emodin in DR-EtOH were higher than those in DR-DW. These results indicated that DR-EtOH could be a good source of natural herbs with anti-osteoporosis properties.
PMCID: PMC4011064  PMID: 24763116
Drynariae rhizoma; extraction solvent; phenolic compounds; antioxidant; anti-osteoporosis
15.  Aggravation of Relapsing Polychondritis due to the Infection and Its Manifestation on a Nasal Tip Graft 
Relapsing polychondritis (RP) is an uncommon systemic disease that is characterized by episodic and progressive inflammation of the cartilaginous structures, which can be very debilitating and in some instances life-threatening. The pathogenic pathways of RP are largely unknown. However, several hypothesis have been suggested. We had an interesting case of aggravation of RP due to the infection. Graft cartilage on the nasal tip was affected by RP also. This case can give a clue of revealing the pathogenesis of RP. We introduce a case with a review of the literature.
PMCID: PMC3932352  PMID: 24587884
Relapsing polychondritis; Nose; Cartilage; Antibody; Foreign-body reaction
16.  Exposure to Dichlorodiphenyltrichloroethane and the Risk of Breast Cancer: A Systematic Review and Meta-analysis 
This study extended and updated a meta-analysis of the association between exposure to dichlorodiphenyltrichloroethane (DDT) and the risk of breast cancer.
We reviewed the published literature on exposure to DDE and breast cancer risk to update a meta-analysis from 2004. The total of 35 studies included 16 hospital-based case–control studies, 11 population-based case–control studies, and 10 nested case–control studies identified through keyword searches in the PubMed and EMBASE databases.
The summary odds ratio (OR) for the identified studies was 1.03 (95% confidence interval 0.95–1.12) and the overall heterogeneity in the OR was observed (I2 = 40.9; p = 0.006). Subgroup meta-analyses indicated no significant association between exposure to DDE and breast cancer risk by the type of design, study years, biological specimen, and geographical region of the study, except from population-based case–control studies with estimated DDE levels in serum published in 1990s.
Existing studies do not support the view that DDE increases the risk of breast cancer in humans. However, further studies incorporating more detailed information on DDT exposure and other potential risk factors for breast cancer are needed.
PMCID: PMC4064641  PMID: 24955316
breast cancer; dichlorodiphenyldichloroethylene; meta-analysis; pesticide exposure; systematic review
17.  Effect of Mechanically Deboned Chicken Meat Hydrolysates on the Physicochemical Properties of Imitation Fish Paste 
This study investigated on the effects of adding mechanically deboned chicken meat (MDCM) hydrolysates on the quality properties of imitation fish paste (IFP) during storage. IFP was prepared from Alaska Pollack, spent laying hens surimi and protein hydrolysates which were enzymatically extracted from MDCM. The study was designed as a 3×4 factorial design with three MDCM hydrolysate content groups (0%, 0.4%, and 0.8%) and four storage times (0, 2, 4, and 6 weeks). Addition of MDCM hydrolysates increased crude fat content but lowered water content (p<0.05). The breaking force of IFP, an indicator of gel formation, increased in treated groups compared to control (p<0.05). Angiotensin I-converting enzyme (ACE) activity was inhibited and free radical scavenging activity increased with increasing MDCM hydrolysate content (p<0.05). In conclusion, the addition of MDCM to IFP improves gel characteristics. Additionally, protein hydrolysates from MDCM serve as a potential source of ACE inhibiting peptides.
PMCID: PMC4093291  PMID: 25049933
Surimi; Imitation Fish Paste; Mechanically Deboned Chicken Meat Hydrolysates; Gel Properties; Lipid Oxidation
18.  Site-specific growth and density control of carbon nanotubes by direct deposition of catalytic nanoparticles generated by spark discharge 
Nanoscale Research Letters  2013;8(1):409.
Catalytic iron nanoparticles generated by spark discharge were used to site-selectively grow carbon nanotubes (CNTs) and control their density. The generated aerosol nanoparticles were deposited on a cooled substrate by thermophoresis. The shadow mask on top of the cooled substrate enabled patterning of the catalytic nanoparticles and, thereby, patterning of CNTs synthesized by chemical vapor deposition. The density of CNTs could be controlled by varying the catalytic nanoparticle deposition time. It was also demonstrated that the density could be adjusted by changing the gap between the shadow mask and the substrate, taking advantage of the blurring effect of the deposited nanoparticles, for an identical deposition time. As all the processing steps for the patterned growth and density control of CNTs can be performed under dry conditions, we also demonstrated the integration of CNTs on fully processed, movable silicon microelectromechanical system (MEMS) structures.
PMCID: PMC3850720  PMID: 24090218
Carbon nanotubes; Thermophoresis; Patterning; Spark discharge; Chemical vapor deposition
19.  Evaluation of Airborne Particle Emissions from Commercial Products Containing Carbon Nanotubes 
The emission of the airborne particles from epoxy resin test sticks with different CNT loadings and two commercial products were characterized while sanding with three grit sizes and three disc sander speeds. The total number concentrations, respirable mass concentrations, and particle size number/mass distributions of the emitted particles were measured using a condensation particle counter, an optical particle counter, and a scanning mobility particle sizer. The emitted particles were sampled on a polycarbonate filter and analyzed using electron microscopy. The highest number concentrations (arithmetic mean = 4670 particles/cm3) were produced with coarse sandpaper, 2% (by weight) CNT test sticks and medium disc sander speed, whereas the lowest number concentrations (arithmetic mean = 92 particles/cm3) were produced with medium sandpaper, 2% CNT test sticks and slow disc sander speed. Respirable mass concentrations were highest (arithmetic mean = 1.01 mg/m3) for fine sandpaper, 2% CNT test sticks and medium disc sander speed and lowest (arithmetic mean = 0.20 mg/m3) for medium sandpaper, 0% CNT test sticks and medium disc sander speed. For CNT-epoxy samples, airborne particles were primarily micrometer-sized epoxy cores with CNT protrusions. No free CNTs were observed in airborne samples, except for tests conducted with 4% CNT epoxy. The number concentration, mass concentration, and size distribution of airborne particles generated when products containing CNTs are sanded depends on the conditions of sanding and the characteristics of the material being sanded.
PMCID: PMC3507461  PMID: 23204914
Airborne particles; Carbon nanotubes; Number concentration; Particle size distribution; Respirable mass concentration; Sanding
20.  Use of the i-gel™ supraglottic airway device in a patient with subglottic stenosis -a case report- 
Korean Journal of Anesthesiology  2013;65(3):254-256.
The airway management of patients with subglottic stenosis poses many challenges for the anesthesiologists. Many anesthesiologists use a narrow endotracheal tube for airway control. This, however, can lead to complications such as tracheal mucosal trauma, tracheal perforation or bleeding. The ASA difficult airway algorithm recommends the use of supraglottic airway devices in a failed intubation/ventilation scenario. In this report, we present a case of failed intubation in a patient with subglottic stenosis successfully managed during an i-gel™ supraglottic airway device. The device provided a good seal, and allowed for controlled mechanical ventilation with acceptable peak pressures while the patient was in the beach-chair position.
PMCID: PMC3790038  PMID: 24101961
Airway management; Subglottic stenosis
21.  Congenital Internal Hernia Presented with Life Threatening Extensive Small Bowel Strangulation 
Internal hernia (IH) is a rare cause of small bowel obstruction occurs when there is protrusion of an internal organ into a retroperitoneal fossa or a foramen in the abdominal cavity. IH can be presented with acute or chronic abdominal symptom and discovered by accident in operation field. However, various kinds of imaging modalities often do not provide the assistance to diagnose IH preoperatively, but computed tomography (CT) scan has a high diagnostic accuracy. We report a case of congenital IH in a 6-year-old boy who experienced life threatening shock. CT scan showed large amount of ascites, bowel wall thickening with poor or absent enhancement of the strangulated bowel segment. Surgical exploration was performed immediately and had to undergo over two meters excision of strangulated small bowel. To prevent the delay in the diagnosis of IH, we should early use of the CT scan and take urgent operation.
PMCID: PMC3819693  PMID: 24224153
Intestinal obstruction; Hernia; Child
22.  Mechanical Stretching for Tissue Engineering: Two-Dimensional and Three-Dimensional Constructs 
Mechanical cell stretching may be an attractive strategy for the tissue engineering of mechanically functional tissues. It has been demonstrated that cell growth and differentiation can be guided by cell stretch with minimal help from soluble factors and engineered tissues that are mechanically stretched in bioreactors may have superior organization, functionality, and strength compared with unstretched counterparts. This review explores recent studies on cell stretching in both two-dimensional (2D) and three-dimensional (3D) setups focusing on the applications of stretch stimulation as a tool for controlling cell orientation, growth, gene expression, lineage commitment, and differentiation and for achieving successful tissue engineering of mechanically functional tissues, including cardiac, muscle, vasculature, ligament, tendon, bone, and so on. Custom stretching devices and lab-specific mechanical bioreactors are described with a discussion on capabilities and limitations. While stretch mechanotransduction pathways have been examined using 2D stretch, studying such pathways in physiologically relevant 3D environments may be required to understand how cells direct tissue development under stretch. Cell stretch study using 3D milieus may also help to develop tissue-specific stretch regimens optimized with biochemical feedback, which once developed will provide optimal tissue engineering protocols.
PMCID: PMC3402846  PMID: 22335794
23.  Osteoblastic/Cementoblastic and Neural Differentiation of Dental Stem Cells and Their Applications to Tissue Engineering and Regenerative Medicine 
Recently, dental stem and progenitor cells have been harvested from periodontal tissues such as dental pulp, periodontal ligament, follicle, and papilla. These cells have received extensive attention in the field of tissue engineering and regenerative medicine due to their accessibility and multilineage differentiation capacity. These dental stem and progenitor cells are known to be derived from ectomesenchymal origin formed during tooth development. A great deal of research has been accomplished for directing osteoblastic/cementoblastic differentiation and neural differentiation from dental stem cells. To differentiate dental stem cells for use in tissue engineering and regenerative medicine, there needs to be efficient in vitro differentiation toward the osteoblastic/cementoblastic and neural lineage with well-defined and proficient protocols. This would reduce the likelihood of spontaneous differentiation into divergent lineages and increase the available cell source. This review focuses on the multilineage differentiation capacity, especially into osteoblastic/cementoblastic lineage and neural lineages, of dental stem cells such as dental pulp stem cells (DPSC), dental follicle stem cells (DFSC), periodontal ligament stem cells (PDLSC), and dental papilla stem cells (DPPSC). It also covers various experimental strategies that could be used to direct lineage-specific differentiation, and their potential applications in tissue engineering and regenerative medicine.
PMCID: PMC3357080  PMID: 22224548
24.  Analysis of the association between necrotizing enterocolitis and transfusion of red blood cell in very low birth weight preterm infants 
Korean Journal of Pediatrics  2013;56(3):112-115.
To investigate the association between necrotizing enterocolitis (NEC) and red blood cell transfusions in very low birth weight (VLBW) preterm infants.
We studied were 180 VLBW preterm infants who were admitted to the neonatal intensive care unit of CHA Gangnam Hospital from January of 2006 to December of 2009. The subjects were divided into 2 groups: an NEC group (greater than stage II on the modified Bell's criteria) and a control group (less than stage II on the modified Bell's critieria). We defined red blood cell transfusion before NEC diagnosis as the frequency of transfusion until NEC diagnosis (mean day at NEC diagnosis, day 18) in the NEC group and the frequency of transfusion until 18 days after birth in the control group.
Of the 180 subjects, 18 (10%) belonged to the NEC group, and 14 (78%) of these 18 patients had a history of transfusion before NEC diagnosis. The NEC group received 3.1±2.9 transfusions, and the control group received 1.0±1.1 transfusions before the NEC diagnosis (P=0.005). In a multivariate logistic regression corrected for gestational age, Apgar score at 1 minute, the presence of respiratory distress syndrome, patent ductus arteriosus, premature rupture of membrane, disseminated intravascular coagulopathy and death were confounding factors. The risk of NEC increased 1.63 times (95% confidence interval, 1.145 to 2.305; P=0.007) with transfusion before the NEC diagnosis.
The risk for NEC increased significantly with increased transfusion frequency before the NEC diagnosis.
PMCID: PMC3611044  PMID: 23559972
Necrotizing enterocolitis; Very low birth weight infants; Red blood cell transfusion
25.  Exercise-Induced Intranodal Atrioventricular Block 
Korean Circulation Journal  2012;42(10):698-701.
Exercise-induced atrioventricular (AV) block in patients with normal AV conduction at rest is rare. Herein, we describe the case of a 67-year-old woman with normal 1 : 1 AV conduction at rest, who developed complete AV block during a treadmill test. Our patient complained of effort-related dizziness and dyspnea, which had been ongoing for 3 months. The patient's physical examination was normal. The resting electrocardiogram showed left anterior fascicular block with a PR interval of 0.19 seconds. The echocardiogram was normal except for mild aortic valve regurgitation. During the treadmill test, the patient developed complete AV block at a sinus rate of 90 beats/min, which was followed by 2 : 1 AV block associated with dyspnea and dizziness. The patient's coronary angiogram was normal, and the ergonovine provocation test was negative. Electrophysiological studies demonstrated rate-dependent intranodal AV block. The patient received implantation of a permanent dual chamber (DDD) pacemaker and had no further symptoms during the follow-up period.
PMCID: PMC3493807  PMID: 23170098
Atrioventricular block; Exercise test; Electrophysiologic techniques, cardiac

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