• Korean Journal of Weed Science
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• v.15 no.1
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• pp.19-29
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• 1995

The effect of seeding depth on the growth, mesocotyl elongation and herbicidal response of rice(Oryza sativa L., Japonica type, cv. "Tongjin") and barnyardgrass(Echinochloa crus-galli Beauv. var orizicola Ohwi.) were studied in greenhouse experiments. Barnyardgrass growth as affected by different water depths was briefly tested. Rice and barnyardgrass were broadcast in soil into Oem, 1cm, 2cm and 3cm in seeding depth under dry direct-seeded condition. Butachlor(N-(buthoxymethyl)-2-chloro-N-(2,6-diethylphenyl) acetamide) at dose rate of 1800g ai/ha and thiobencarb(S-[(4-chlorophenyl)methyl] diethyl carbamothioate) at dose rate of 2100g and 4200g ai/ha were soil applied to them at 5 days after seeding. At 10 days after seeding, plants harvested to examine their growth as affected by seeding depth. Root length and shoot fresh weight of rice untreated was greatest in 1cm- and 3cm-seeding depth, respectively, however, mesocotyl did not elongate. While plant height of barnyardgrass grew regardless of seeding depth and water depth, but root length was greatest in 1cm-seeding depth of dry condition and reduced with increased water depth. And mesocotyl was elongated in only dry condition and its length increased with increased seeding depth. At 10 days after application thiobencarb applied pre-emergence inhibited plant height, and shoot fresh weight of rice in only 0cm-seeding depth under dry condition whereas was unaffected in above 1cm-seeding depth, similar to untreated control, and ever increased root length and root fresh weight of rice. On the other hand, shoot, root and leaf growth of barnyardgrass was, severely inhibited regardless of application rates and seeding depths. Reduction of shoot growth by treatment of herbicide was significantly greater than that of root growth. Consequently, reduction of barnyardgrass growth by treatment of thiobencarb did not be associated with seeding depth and mesocotyl elongation as affected by different seeding depth.

• Korean Journal of Weed Science
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• v.16 no.1
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• pp.21-27
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• 1996

This experiment was conducted to find out an effective propagation method for reed(Phragmites communis Trin.), ensuring a continuous herbicide screening for reed control. Reed propagation methods were compared under a greenhouse condition using tour different materials; seeds, rhizomes, depressed stolons of P. japonica Steud., and stem cuttings. Although reed seeds were easy to harvest and store, their germination rate(${\leq}$5%) was very low and seedling growth from the seeds was slow. Rhizomes were difficult to harvest and their harvest time was limited from November to March. Furthermore, reed propagation using rhizomes had problems of a relatively low germination rate(46%), no uniformity in size and shape, individual differences at the early stage of growth, and difficulties in material storage. Rate of reed growth from rhizomes was higher in commercial soil mix(Boo Nong soil) than in sand or in sand+upland soil(1:1). Depressed stolons of P. japonica had a moderate germination rate(65%) and were relatively easy to harvest. However, their harvest time was limited only from August to September. Propagation method using stem cuttings had several advantages over the above methods using other materials. Reed plants could uniformly be propagated from the stem cuttings with a relatively high germination rate(75%). Stem cuttings of central nodes showed a higher germination rate compared to those of upper or lower nodes. Stem cuttings from the field should be used immediately after harvest, since their germination rate decreased rapidly when they were stored under a wet- or a dry-refrigerated condition. Furthermore, the germination of stem cuttings tended to decrease when they were collected from the field after August. This indicates that there is a limitation of harvest time for stem cuttings. However, a year-round propagation of reed using stem cuttings is possible if parent plants are grown in a greenhouse, and thus herbicide screening for reed control could continuously be performed.

• Weed & Turfgrass Science
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• v.6 no.3
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• pp.203-211
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• 2017

This study was conducted to investigate the phytotoxicity of main rice varieties and control efficacy of HPPD inhibitor to major paddy weeds at the time of temperature rise due to climate change. Phytotoxicity of herbicide to rice was increased as temperature was increased, and more severe in root than shoot. The phytotoxicity of japonica rice cultivars for the rice were mild enough to recover. However, glutinous rice, super high yield rice, and Tongil rice varieties were damaged enough to decrease the yield. Shindongjinbyeo transplanted by June 15, showed phytotoxicity enough to recover. However, in the rice field on June 30 and on July 15, the rice showed a remarkable inhibition. The control effect of Monochoria vaginalis and Scirpus juncoides was more than 90% under the temperature condition controlled artificially. However, Echinochloa oryzicola was controlled 40% at $27.5^{\circ}C$, which is a high temperature condition. In rice fields with different transplanting times, annual weeds except for E. oryzicola were highly controlled by 90% or more regardless of the time of transplanting.

• Journal of Chest Surgery
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• v.35 no.3
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• pp.217-222
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• 2002

Background: The incidence of gastroesophageal reflux disease(GERD) is increasing recently, but medical management for GERD has many limitations. Therefore, variable surgical treatments have been introduced. Material and Method: A retrospective study was done in 10 patients who underwent the Belsey Mark IV operation at Korea university Guro hospital between 1996 and 2001. Preoperative diagnoses were hiatal hernia with gasroesophageal reflux in 8 patients and achalasia in 2 patients. Result: Mean age of the patients was 54.3$\pm$19.0 years. Belsey Mark IV operation was performed on patients where preoperative medical failed and mean hospital days were 13.1$\pm$2.6 days. We routinely practiced follow-up endoscopy on postoperative 3rd, 6th, 9th, and 12th months. After remission for reflux and esophagitis, they were transferred to internal medicine department. Six patients of hiatal hernia with reflux (one patient who lost follow-up and the other patient who didn't practice the follow-up endoscopy due to short postoperative follow-up period were excluded) had lowered endoscopic gradings and two patients of achalasia did not complained of reflux symptoms, postoperatively. We experienced 10% operation failure rate. Conclusion: We experienced satisfactory operation results with Belsey Mark IV in hiatal hernia with GERD and achalasia patients.

• Journal of Chest Surgery
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• v.39 no.11 s.268
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• pp.815-821
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• 2006

Background: Carotid endarterectomy is an effective treatment modality in patients with severe carotid artery stenosis, but it may result in serious postoperative complications, We analyzed the results of the carotid endarterectomy performed in our institution to reduce the complications related to the card endarterectomy. Material and Method: We analyzed retrospectively the medical records of 74 patients(76 cases) who underwent carotid endarterectomy for carotid artery stenosis by a single surgeon from February 1996 to July 2004. Result: There were 64 men and 10 women. The mean age of the patients was 63.6 years old. Carotid endarterectomy only was performed in 63 cases, carotid endarterectomy with patch angioplasty in 8 cases, and carotid endarterectomy with segmental resection of internal carotid artery and end to end anastomosis in 5 cases. Intra-arterial shunt was used in 29 cases. The mean back pressures of internal carotid arteries checked after clamping common carotid arteries and external carotid arteries were $23.48{\pm}10.04$ mmHg in 25 cases with changes in electroencephalography(group A) and $47.16{\pm}16.04$ mmHg in 51 cases without changes in electroencephalography(group B). There was no statistical difference in the mean back pressure of internal carotid arteries between two groups(p=0.095), but the back pressures of internal carotid arteries of all patients with changes in electroencephalography were under 40 mmHg. When there was no ischemic change of electroencephalography after clamping common carotid artery and external carotid artery, we did not make use of intra-arterial shunt regardless of the back pressure of internal carotid artery. Operative complications were transient hypoglossal nerve palsy in four cases, cerebral hemorrhage occurred at previous cerebral infarction site in two cases, mild cerebral infarction in one case, hematoma due to anastomosis site bleeding in one case, and upper airway obstruction due to laryngeal edema probably caused by excessive retraction during operation in two cases. One patient expired due to cerebral hemorrhage occurring at previous cerebral infarction site. Conclusion: Carotid endarterectomy is a safe operative procedure showing low operative mortality. We suggest that intra-arterial shunt usage should be decided according to the ischemic change of electroercephalography regardless of the back pressure of internal carotid artery. Excessive retraction during operation should be avoided to prevent upper alway obstruction due to laryngeal edema and if upper airway obstruction is suspected, prompt management is essential.

• Neonatal Medicine
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• v.16 no.2
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• pp.182-189
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• 2009

Purpose: Recently, it is easy to find the causal virus of acute respiratory infections using multiplex RT-PCR. The aim of this study is to show the distribution of respiratory viruses and to define the characteristics of respiratory syncytial virus (RSV) infections compared to other respiratory viral infections. Methods: This was a prospective observational study conducted in the NICU. The infants with acute respiratory infections were performed multiplex RT-PCR using nasal swabs. The demographics, initial symptoms, course of illness, and laboratory and imaging findings were recorded. The infants were divided into RSV and No RSV groups. Results: Twenty-three infants (50%) were in the RSV group. Rhinovirus was the second most common virus. Coinfections with two viruses accounted for 6.5% of respiratory infections. The number of preterm infants, exposure to cigarette smoke and having siblings were not different between the two groups. Infections in the postnatal care center were more common in the RSV group than the No RSV group (60.9% vs. 21.7%, P=.007). Dyspnea (34.8% vs. 8.7%, P=.032) and pneumonia (73.9% vs. 43.5%, P=.036) were more common in the RSV group. The RSV group frequently needed oxygen (52.5% vs. 13.0%, P=.005) and received nothing by mouth (43.5% vs. 13.0%, P=.022). The incidence of right upper consolidation was higher in RSV group (56.5% vs. 8.7%, P=.001). Conclusion: This study showed that other viruses than RSV can induce respiratory infections in neonates and young infants born prematurely. RSV infections have a more severe course of illness than other respiratory viruses. We have to be careful of prevention even for healthy neonates especially in crowed situations, such as the postnatal care center.

• 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.17 no.1
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• pp.53-63
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• 2010

Purpose : Extrauterine growth restriction (EUGR) in preterm infants is a major problem in neonatal intensive care units (NICUs) and it has been related to long-term growth deficit and neurodevelopmental issues. The aim of this study was to investigate the frequency of and risk factors for EUGR. Methods : The study subjects consisted of very low birth weight (VLBW) infants with a gestational age $\leq$32 weeks that were born at the Seoul National University Children's Hospital between November 2005 and April 2009. EUGR was defined as weight for gestation, lower than the 10th percentile on discharge. Results : The frequency of EUGR was 67% (n=111/166). By multiple logistic regression, the presence of small for gestational age (SGA) was the greatest predictor of EUGR, birth weight and daily weight gain during the first 28 days were independent predictors of EUGR. Risk factors for EUGR in non-SGA infants were evaluated because 56% (64/114) of non-SGA infants developed EUGR at discharge. Daily weight gain in the first 28 days was also decreased in EUGR group and independently predicted the risk of EUGR in the non-SGA group. Conclusion : EUGR was a common problem in the NICU. SGA was the most significant predictive factor of the EUGR. Half of the non-SGA infants also developed EUGR, revealing poor weight gain in the early days was as an important predictor. These results support the importance of early nutritional intervention for weight gain which have lagged behind other modern therapeutic interventions when the infant is clinically unstable.

• Neonatal Medicine
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• v.16 no.2
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• pp.221-233
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• 2009

Purpose: Erythropoietin (EPO) has neuroprotective effects in many animal models of brain injury, including hypoxic-ischemic (HI) encephalopathy, trauma, and excitotoxicity. Current studies have demonstrated the neuroprotective effects of EPO, but limited data are available for the neonatal periods. Here in we investigated whether recombinant human EPO (rHuEPO) can protect the developing rat brain from HI injury via modulation of NMDA receptors. Methods: In an in vitro model, embryonic cortical neuronal cell cultures from Sprague-Dawley (SD) rats at 19-days gestation were established. The cultured cells were divided into five groups: normoxia (N), hypoxia (H), and 1, 10, and 100 IU/mL rHuEPO-treated (H+E1, H+ E10, and H+E100) groups. To estimate cell viability and growth, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay was done. In an in vivo model, left carotid artery ligation was performed on 7-day-old SD rat pups. The animals were divided into six groups; normoxia control (NC), normoxia Sham-operated (NS), hypoxia-ischemia only (H), hypoxia-ischemia+vehicle (HV), hypoxia-ischemia+rHuEPO before a HI injury (HE-B), and hypoxia-ischemia+rHuEPO after a HI injury (HE-A). The morphologic changes following brain injuries were noted using hematoxylin and eosin (H/E) staining. Real-time PCR using primers of subunits of NMDA receptors (NR1, NR2A, NR2B, NR2C and NR2D) mRNA were performed. Results: Cell viability in the H group was decreased to less than 60% of that in the N group. In the H+E1 and H+E10 groups, cell viability was increased to >80% of the N group, but cell viability in the H+E100 group did not recover. The percentage of the left hemisphere area compared the to the right hemisphere area were 98.9% in the NC group, 99.1% in the NS group, 57.1% in the H group, 57.0% in the HV group, 87.6% in the HE-B group, and 91.6% in the HE-A group. Real-time PCR analysis of the expressions of subunits of NMDA receptors mRNAs in the in vitro and in vivo neonatal HI brain injuries generally revealed that the expression in the H group was decreased compared to the N group and the expressions in the rHuEPO-treated groups was increased compared to the H group. Conclusion: rHuEPO has neuroprotective property in perinatal HI brain injury via modulation of N-methyl-D-aspartate receptors.

• Neonatal Medicine
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• v.17 no.1
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• pp.94-101
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• 2010

Purpose:In recent years, Korea has showed a steady increase in the frequency of teenage birth, while the overall birth rate has declined. As the teenage birth is known as a high risk pregnancy itself, we examined perinatal complications of teenage mothers and whose neonates in aspects of medical problem, and social status and support. Methods:We examined the perinatal characteristics of teenage mothers and whose babies, who were hospitalized at Korea University Ansan Hospital from January 2004 to July 2009 using medical records retrospectively. Twenty-seven teenage mothers and their 28 babies were enrolled in this study. Results:Teenage mothers were all unmarried and showed high rates of preterm labor, maternal anemia, and unexpected delivery. Among them, 11 (40.7%) were from families that were separated. Eleven mothers (40.7%) did not have any antenatal care. There were high rates of prematurity and low birth weight (60.7% and 64.3%, respectively). The complication included: respiratory distress syndrome, patent ductus arteriosus and necrotizing enterocolitis. Fourteen babies (51.9%) were not going to be brought up by their biological parents. Conclusion:Teenage pregnancy had high rates of preterm labor and associated complications, often caused by the lack of proper antenatal care. Babies from unmarried mothers were likely to be adopted and this could be a social burden. Therefore, to reduce unplanned teenage pregnancy and births, sex education and social supports should be provided to all teenagers.