Ju Young Chang

Pyrosequencing-based molecular monitoring of the intestinal bacterial colonization in preterm infants.

Objectives: The aim of the study was to investigate the previously unexplored diversity of neonatal intestinal microbiota and monitor early intestinal colonization patterns in Korean preterm infants using high-throughput pyrosequencing technology combined with 16S rDNA-based molecular methods. Subjects and Methods: A total of 46,369 partial 16S rDNA sequences obtained from 30 fecal samples serially taken from 10 very-low-birth weight preterm infants were analyzed. Results: A significant proportion of the molecular species (21.9%) was found to be unclassified. The pathogenic or potentially pathogenic molecular species belonging to the classes Gammaproteobacteria and Bacilli were predominant during the entire observation period. Anaerobic or nonpathogenic molecular species belonging to the class Clostridia (except Clostridium difficile) and phyla Bacteroidetes were ubiquitous even within 72 hours after birth. The proportion of these species increased significantly at 1 month of age. The most ubiquitous and abundant major molecular genera common to all of the postnatal ages were Escherichia, Enterobacter, Enterococcus, Veillonella, Serratia, Staphylococcus, Roseburia, Acinetobacter, Citrobacter, Bacteroides, Faecalibacterium, Blautia, and Streptococcus. Conclusions: The diversity and dynamic nature of intestinal bacterial colonization in very-low-birth weight preterm infants were revealed using pyrosequencing technology. The results of the present pilot study may provide a basis to consider when investigating or interpreting the role of intestinal microbiota in certain preterm infant diseases such as necrotizing enterocolitis or systemic infection.

Clinical features of congenital portosystemic shunt in children

Clinical features, images, complications, treatments, and prognosis of 10 children with congenital portosystemic shunt (CPSS) were reviewed. Nine children were diagnosed with intrahepatic shunts while one presented with extrahepatic shunt. CPSS was detected by prenatal ultrasonography in four infants. Three infants presented with galactosemia without an enzyme deficiency. Two children presented with mental retardation and attention deficit hyperactivity disorder. Pulmonary hypertension developed in two patients. Spontaneous closure occurred in four infants with intrahepatic shunts including patent ductus venosus. The shunts were closed using transcatheter embolizations in four patients with intrahepatic shunts. Conclusion: Intrahepatic shunts may close spontaneously. Transcatheter embolization is effective for the treatment of symptomatic intrahepatic shunts.

Comparison of Explant-Derived and Enzymatic Digestion-Derived MSCs and the Growth Factors from Wharton’s Jelly

Whartons jelly is not only one of the most promising tissue sources for mesenchymal stem cells (MSCs) but also a source of natural growth factors. To prove that we can get both natural growth factors and MSCs from Whartons jelly, we compared cellular characteristics and the level of basic fibroblast growth factor (bFGF) from samples using the explant culture method to those derived from the traditional enzymatic culture method. The levels of bFGF were 27.0 ± 11.7 ng/g on day 3, 15.6 ± 11.1 ng/g on day 6, and decreased to 2.6 ± 1.2 ng/g on day 14. The total amount of bFGF released was 55.0 ± 25.6 ng/g on explant culture. Compared with the traditional enzymatic digestion method, the explant culture method showed a tendency to release higher levels of bFGF in supernatant media for the first week of culture, and the higher cellular yield at passage 0 (4.89 ± 3.2 × 105/g versus 1.75 ± 2.2 × 105/g, P = 0.01). In addition, the genes related to mitosis were upregulated in the explant-derived MSCs.

Temperature gradient interaction chromatography of low molecular weight polystyrene

Separation of low molecular weight polystyrene (PS) by temperature gradient interaction chromatography (TGIC) is reported. As in the separation of high molecular weight PS, temperature is an efficient variable to control the retention of low molecular weight PS in the reversed phase HPLC separation. However, a right choice of the eluent, typically a marginal solvent for the polymeric solute of interest, is crucial for the temperature to play an effective role in the retention control. For an example, PS oligomers were well separated by TGIC under the isocratic elution condition of C18 bonded silica and methanol as the stationary and the mobile phase, respectively.

Rheological properties of hyaluronic acid and its effects on salivary enzymes and candida

OBJECTIVE To investigate the viscosity and wettability of hyaluronic acid (HA), its effects on lysozyme and peroxidase activities, and its candidacidal activity. MATERIALS AND METHODS Human whole saliva, HA, hen egg-white lysozyme (HEWL), and bovine lactoperoxidase (bLPO) were used. Viscosity was measured with a cone-and-plate digital viscometer, while wettability was determined by measuring the contact angle. Lysozyme activity was determined by the turbidimetric method. Peroxidase activity was determined with NbsSCN assay. Candidacidal activity was determined by comparing colony forming units. RESULTS The viscosity of HA solutions was proportional to its concentration, with 0.05 mg ml(-1) of HA in distilled water or 0.5 mg ml(-1) in simulated salivary buffer displaying similar viscosity values to stimulated whole saliva. The contact angle of HA solutions showed no significant differences according to the tested materials and tested HA concentrations. Contact angles of HA solutions on acrylic resin were higher than those of human saliva. HA did not affect lysozyme or peroxidase activities of whole saliva as well as HEWL or bLPO activities. HA also showed no candidacidal activity. CONCLUSIONS The viscoelastic properties of HA compared with human saliva were objectively confirmed, indicating a vital role for HA in the development of effective salivary substitutes.

Genetically confirmed Wilson disease in a 9-month old boy with elevations of aminotransferases.

Wilson disease (WD) is an autosomal recessive disorder of copper transport caused by alteration of the adenosine triphosphatase 7B gene. It is rare to diagnose WD below the age of three years. Molecular genetic testing is one of the most important diagnostic methods and may confirm the diagnosis in equivocal cases. We report a case of a 9-mo old boy with WD who presented as chronic hepatitis. Genetic analysis showed compound heterozygotes of p.G1186S and c.4006delA.

Epstein-Barr Virus Infection with Acute Acalculous Cholecystitis

Acute acalculous cholecystitis (AAC) is an inflammation of the gallbladder in the absence of demonstrated stones. AAC is frequently associated with severe systemic inflammation. However, the exact etiology and pathogenesis of AAC still remain unclear. Acute infection with Epstein Barr virus (EBV) in childhood is usually aymptomatic, whereas it often presents as typical infectious mononucleosis symptoms such as fever, cervical lymphadenopathy, and hepatosplenomegaly. AAC may occur during the course of acute EBV infection, which is rarely encountered in the pediatric population. AAC complicating the course of a primary EBV infection is usually associated with a favorable outcome. Most of the patients recover without any surgical treatment. Therefore, the detection of EBV in AAC would be important for prediction of better prognosis. We describe the case of a 10-year-old child who presented with AAC during the course of primary EBV infection, the first in Korea, and review the relevant literature.

Mercury Exposure in Healthy Korean Weaning-Age Infants: Association with Growth, Feeding and Fish Intake

Low-level mercury (Hg) exposure in infancy might be harmful to the physical growth as well as neurodevelopment of children. The aim of this study was to investigate postnatal Hg exposure and its relationship with anthropometry and dietary factors in late infancy. We recruited 252 healthy Korean infants between six and 24 months of age from an outpatient clinic during the 2009/2010 and 2013/2014 seasons. We measured the weight and height of the infants and collected dietary information using questionnaires. The Hg content of the hair and blood was assessed using inductively coupled plasma mass spectroscopy. The geometric mean Hg concentration in the hair and blood was 0.22 (95% confidence interval: 0.20–0.24) µg/g and 0.94 (n = 109, 95% confidence interval: 0.89–0.99) µg/L, respectively. The hair Hg concentration showed a good correlation with the blood Hg concentration (median hair-to-blood Hg ratio: 202.7, r = 0.462, p < 0.001) and was >1 µg/g in five infants. The hair Hg concentration showed significant correlations with weight gain after birth (Z-score of the weight for age—Z-score of the birthweight; r = −0.156, p = 0.015), the duration (months) of breastfeeding as the dominant method of feeding (r = 0.274, p < 0.001), and the duration of fish intake more than once per week (r = 0.138, p = 0.033). In an ordinal logistic regression analysis with categorical hair Hg content (quartiles), dietary factors, including breastfeeding as the dominant method of feeding in late infancy (cumulative odds ratio: 6.235, 95% confidence interval: 3.086–12.597, p < 0.001) and the monthly duration of fish intake more than once per week (cumulative odds ratio: 1.203, 95% confidence interval: 1.034–1.401; p = 0.017), were significantly associated with higher hair Hg content. Weight gain after birth was not, however, significantly associated with hair Hg content after adjustment for the duration of breastfeeding as the dominant method of feeding. Low-level Hg exposure through breastfeeding and fish intake as a complementary food did not directly affect anthropometry in this population. If prolonged breastfeeding is expected, however, the Hg exposure through fish intake may need to be monitored for both mothers and infants.

Epidemiology and Factors Related to Clinical Severity of Acute Gastroenteritis in Hospitalized Children after the Introduction of Rotavirus Vaccination

We aimed to investigate epidemiology and host- and pathogen-related factors associated with clinical severity of acute gastroenteritis (AGE) in children after rotavirus vaccination introduction. Factors assessed included age, co-infection with more than 2 viruses, and virus-toxigenic Clostridium difficile co-detection. Fecal samples and clinical information, including modified Vesikari scores, were collected from hospitalized children with AGE. The presence of enteric viruses and bacteria, including toxigenic C. difficile, was detected by polymerase chain reaction (PCR). Among the 415 children included, virus was detected in stool of 282 (68.0%) children. Co-infection with more than 2 viruses and toxigenic C. difficile were found in 24 (8.5%) and 26 (9.2%) children with viral AGE, respectively. Norovirus (n = 130) infection, including norovirus-associated co-infection, was the most frequent infection, especially in children aged < 24 months (P < 0.001). In the severity-related analysis, age < 24 months was associated with greater diarrheal severity (P < 0.001) and modified Vesikari score (P = 0.001), after adjustment for other severity-related factors including rotavirus status. Although the age at infection with rotavirus was higher than that for other viruses (P = 0.001), rotavirus detection was the most significant risk factor for all severity parameters, including modified Vesikari score (P < 0.001). Viral co-infection and toxigenic C. difficile co-detection were not associated with any severity-related parameter. This information will be helpful in the management of childhood AGE in this era of rotavirus vaccination and availability of molecular diagnostic tests, which often lead to the simultaneous detection of multiple pathogens.

A mutation analysis of the AGL gene in Korean patients with glycogen storage disease type III

Glycogen storage disease type III (GSD III) is an autosomal recessive disorder that is characterized by the excessive accumulation of abnormal glycogen in the liver and muscles and is caused by a deficiency in glycogen debranching enzyme (amylo-1,6-glucosidase, 4-alpha-glucanotransferase (AGL)) activity. To investigate the molecular characteristics of GSD III patients in Korea, we have sequenced the AGL gene in eight children with GSD III. All patients were compound heterozygotes. We identified 10 different mutations (five novel and five previously reported). The novel mutations include one nonsense (c.1461G>A, p.W487X), three splicing (c.293+4_293+6delAGT in IVS4, c.460+1G>T in IVS5, c.2682-8A>G in IVS21) and one missense mutation (c.2591G>C, p.R864P). Together, p.R285X, c.1735+1G>T and p.L1139P accounted for 56% of all alleles, while the remaining mutations are heterogeneous. These three mutations can be common in Korea, and further larger studies are needed to confirm our findings.