• Neonatal Medicine
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• v.17 no.1
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• pp.21-33
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• 2010

Purpose : The increased survival of preterm infants in the neonatal intensive care unit recently has resulted in an increased frequency of bronchopulmonary dysplasia (BPD), especially with atypical forms. However, there have been few studies compairing classic and atypical BPD. The aim of this study was to investigate the differences between these two types of BPD. Methods : Infants with a gestational age less than 32 weeks born at the Seoul National University Hospital and Bundang Seoul National University Hospital from May 2004 to April 2007 were included. The data were categorized in 2 groups, classic and atypical BPD. We determined the incidence of BPD, and compared perinatal factors and postnatal managements between two groups. Results : Among 260 study subjects, 141 (54.2%) infants had BPD. Classic BPD infants were 64 and atypical BPD infants were 77. Comparison of differences between 2 groups, classic BPD infants were associated with respiratory distress syndrome, patent ductus arteriosus, intrauterine growth restriction, more high-frequency ventilator (HFV) use, low 1 and 5 minute Apgar scores. Atypical BPD infants were associated with antenatal steroid use, maternal premature rupture of membrane and chorioamnionitis (CAM). In multivariate analysis, more HFV use was associated with classic BPD. Antenatal steroid use, clinical CAM and histological CAM were associated with atypical BPD. Conclusion : The results of this study showed that antenatal factors (antenatal steroid use, clinical CAM, histological CAM) were associated with atypical BPD and postnatal factors (HFV used more) were associated with classic BPD. Further studies are needed for prevention and treatment of BPD.

• Neonatal Medicine
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• v.16 no.2
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• pp.154-162
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• 2009

Purpose: Death is an important problem for physicians and parents in neonatal intensive care unit. This study was intended to evaluate the mortality rate, causes of death, and the change of mortality rate by year for infants admitted to the neonatal intensive care unit. Methods: We retrospectively surveyed the medical records of the infants who were admitted to the neonatal intensive care unit at Asan Medical Center and who died before discharge between 1998 and 2007. Gestational age, birth weight, gender, time to death and the underlying diseases related to the causes of infant deaths and obtained from the medical records and analyzed according to year. Results: A total of 6,289 infants were admitted and 264 infants died during the study period. The overall mortality rate was 4.2%. For very low and extremely low birth weight infants, the mortality rate was 10.6% and 21.4%, respectively. There was no significant change in the mortality rate during the study period. Prematurity related complications and congenital anomalies were the conditions most frequently associated with death in the neonatal intensive care unit. of the infant deaths 37.1% occurred within the first week of life. Conclusion: Even though a remarkable improvement in neonatal intensive care has been achieved in recent years, the overall mortality rate has not changed. To reduce the mortality rate, it is important to control sepsis and prevent premature births. The first postnatal week is a critical period for deaths in the neonatal intensive care unit.

• Journal of Genetic Medicine
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• v.8 no.1
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• pp.1-16
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• 2011

Owing to the risk of fetal loss associated with prenatal diagnostic procedures (amniocentesis, chorionic villus sampling), noninvasive prenatal diagnosis (NIPD) is ultimate goal of prenatal diagnosis. The discovery of circulating cell-free fetal DNA (cffDNA) in maternal plasma in 1997 has opened up new probabilities for NIPD by Dr. Lo et al. The last decade has seen great development in NIPD. Fetal sex and fetal RhD status determination by cffDNA analysis is already in clinical use in certain countries. For routine use, this test is limited by the amount of cell-free maternal DNA in blood sample, the lack of universal fetal markers, and appropriate reference materials. To improve the accuracy of detection of fetal specific sequences in maternal plasma, internal positive controls to confirm to presence of fetal DNA should be analyzed. We have developed strategies for noninvasive determination of fetal gender, and fetal RhD genotyping using cffDNA in maternal plasma, using real-time quantitative polymerase chain reaction (RT-PCR) including RASSF1A epigenetic fetal DNA marker (gender-independent) as internal positive controls, which is to be first successful study of this kind in Korea. In our study, accurate detection of fetal gender through gestational age, and fetal RhD genotyping in RhD-negative pregnant women was achieved. In this assay, we show that the assay is sensitive, easy, fast, and reliable. These developments improve the reliability of the applications of circulating fetal DNA when used in clinical practice to manage sex-linked disorders (e.g., hemophilia, Duchenne muscular dystrophy), congenital adrenal hyperplasia (CAH), RhD incompatibility, and the other noninvasive pregnant diagnostic tests on the coming soon. The study was the first successful case in Korea using cffDNA in maternal plasma, which has created a new avenue for clinical applications of NIPD.

• Clinical and Experimental Pediatrics
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• v.50 no.8
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• pp.746-752
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• 2007

Purpose : Total hydroperoxide (TH), free radical-mediated oxidation product can be used as a measure of free radical injury. The aim of the present study was to see if preterm newborns are at increased risk for oxidative stress compared with term newborns, and to determine whether oxidative stress during postnatal first 1 week is associated with clinical outcomes in preterm infants. Methods : Serum TH levels of preterm infants (n=39) were compared with those of term infants (n=24) on the postnatal day 1. Among the preterm infants, serum TH levels of uncomplicated group (n=23) were also compared with those of complicated group (n=16) who developed oxygen radical related diseases on the postnatal day 1 and 7. Retrospective analysis was performed to find out risk factors for oxygen radical injuries based on birth history, laboratory data, neuroimaging findings and clinical progress in two preterm groups. Results : Serum TH levels on postnatal day 1 were higher in the preterm infant group than the term infant group. Serum TH levels on postnatal day 1 in the complicated preterm infant group were significantly higher compared with uncomplicated group, but there was no significant difference in serum TH levels on postnatal day 7. Also, there was no significant difference in serum TH levels between uncomplicated preterm infants and term infants. Serum TH level on postnatal day 1 was independently associated with higher morbidity after adjusting for gestational age, Apgar score (5 min), arterial blood gas analysis. Conclusion : Complicated preterm newborns are at increased risk for oxidative stress compared with uncomplicated newborns and term newborns. Oxidative injury during the prenatal or postnatal day 1 is associated with adverse outcomes in preterm infants. Elevated TH levels on postnatal day 1 may have a value to predict clinical outcomes in preterm infants.

• Neonatal Medicine
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• v.15 no.1
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• pp.67-74
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• 2008

Purpose : The purpose of this study was to assess the natural history and perinatal outcomes of twin gestations according to chorionicity. Methods : We retrospectively reviewed the medical records of 99 monochorionic (MC) and 206 dichorionic (DC) twin gestations delivered at Il Sin Christian Hospital in Busan between January 2002 and December 2007. The incidences of twin-to-twin transfusion syndrome (TTS) and selective intrauterine growth restriction (sIUGR), as well as perinatal morbidity and mortality, were evaluated. Results : MC twins had a lower gestational age (35.7 vs. 36.6 weeks, P=0.03) at birth and a higher incidence of intrauterine fetal loss (10% vs. 1.5%, P<0.001) than DC twins. The incidence of intrauterine fetal loss was higher in MC sIUGR than in DC sIUGR (19% vs. 2.5%, P=0.025) twins. The number of admissions to the neonatal intensive care unit (NICU; 31% vs. 16%, P=0.042), and the incidence of periventricular leukomalacia (7% vs. 0%, P=0.031), and respiratory distress syndrome with surfactant treatment (27% vs. 11%, P=0.049) were higher in MC than DC twins. The incidences of sIUGR and TTS were 21 and 9% among the MC twins. The incidences of intrauterine fetal loss were higher in MC twins with TTS [6 of 9 (67%)] or sIUGR [4 of 21 (19%)] than uncomplicated MC twins (P<0.001). The frequency of admission to the NICU (P=0.001), the length of hospital stay (P=0.033), the prevalence of periventricular leukomalacia (P=0.011), and intraventricular hemorrhage (P=0.007) were also higher in MC with TTS or sIUGR than in uncomplicated MC twins. Conclusion : The incidence of neonatal complications was higher in MC twins, especially those gestations complicated by TTS or sIUGR.

• Applied Microscopy
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• v.30 no.2
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• pp.213-232
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• 2000

The development of the knee joint was studied by electron microscopy in human fetuses ranging from 20 mm to 260 mm crown-rump length ($7\sim30$ weeks of gestational age). The appearance of the primordium of the meniscus and cruciate ligament was conspicuous as the mesenchymal cells , preceeding that of joint space at 30 mm fetus. The primitive joint cavity was first seen in the interzone from the 40 mm fetus and its intermediate layer proceeded developing as a narrow cleft which was closely incorporated with two chondrogenic layers. Poorly differentiated mesenchymal cells of the meniscus at 40 mm fetus containing predominantly free ribosomes differentiated into fibroblasts at 60 mm fetus. By 100 mm fetus, the fibroblast in inner zone of the meniscus presented as oval profiles with a short cell processes, whereas middle and peripheral zones presented as elongated cells. Differentiation of the synovial membrane coincided with clarification of the joint cavity When dilatation of the synovial cavity occurred, the two types of synovial cells were identified at 60 mm fetus. By 100 mm fetus a majority of the intimal cells were B-type. B-type cells were clearly distinguishable from A-type cells by their content of extensive rough endoplasmic reticula and well developed Golgi complexes. In contrast, A-type cells had numerous filopodia, pinocytotic vesicles, lysosomes and large vacuoles. At 260 mm fetus the B-type cells were also a majority of intimal cells. At 260 mm fetus the inner zone of the meniscus was filled with parallel oriented fascicles of collagenous fibers and oval fibroblasts. The middle zone was constituted of parallel and radially arranged fibers and fibroblasts. The outer zone was populated by elongated fibroblasts encircled by crossed collagenous fibers with the blood vessels. At 30 mm fetus the fibroblasts of the cruciate ligament contained rough endoplasmic reticula and mitochondria. Collagen fibrils were noted within narrow cytoplasmic processes which were continued with the extracellular space. Collagen fibrils of ligament were filled in the bulk of extracellular space at 100 mm fetus. By $150\sim260mm$ fetus, the cruciate ligaments were constituted of longitudinally oriented bundle of collagen fibrils with irregular rows of round cells between.

• Pediatric Infection and Vaccine
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• v.14 no.2
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• pp.145-154
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• 2007

Purpose : Rotavirus is one of the most important etiologic agents of nosocomial infections among the neonates. This study was designed to investigate nosocomial rotavirus infection in neonates who were admitted to a postpartum-care center after birth. Methods : From March 2005 to September 2006, 957 healthy neonates were examined for rotavirus antigen in stool by immunochromatographic method and 216 neonates were rotavirus antigen positive within 24 hours after admitted to a postpartum-care center. We reviewed the nursing charts retrospectively such as characteristics, monthly distribution, birth hospitals, delivery methods, feeding types and clinical manifestations. Results : Among 957 neonates, 216 neonates (22.6%) were rotavirus antigen positive and there were no differences in sex, birth weight, gestational age. Monthly positive rate of rotavirus antigen showed diversity from 10% to 36%. According to birth hospitals, positive rate showed diversity from 3.5% to 53.6%. Out of 957 neonates, 655 cases (68.4%) were born of vaginal delivery and mean hospitalized duration was 2.4 days, 302 cases (31.6%) were born of cesarean section and mean hospitalized duration was 5.7 days. 17.6% of vaginal delivery and 33.4% of cesarean section were rotavirus antigen positive. The positive rate was higher in neonates by cesarean section than vaginal delivery (P<0.001). According to feeding types, positive rate of rotavirus antigen was lower in breast-fed group than formula-fed group (P<0.001). Proportion of symptomatic case among rotavirus antigen positive was 34.7%. Most common clinical manifestation was diarrhea (61.3%), following poor feeding (45.3%), fever (40.0%), vomiting (25.3%), delayed weight gain (12.0%), and decreased urine amount (5.3%). Conclusion : Some neonates were already infected before admission to a postpartum-care center. Without meticulous management, nosocomial rotavirus infection would transmit rapidly in a postpartum-care center spreading to the community. Recommendation of breast-feeding, routine rotavirus screeing test with or without symptom, and isolation of all rotavirus antigen positive neonates in a postpartum-care center seem to be necessary. Also attentive hygiene education and further investigations of rotavirus infection in a postpartum-care center would be needed.