• Biomedical Science Letters
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• v.8 no.3
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• pp.115-125
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• 2002

Gram-negative septicemia, which continues to be a serious clinical problem, is one of the major causes of morbidity and mortality in hospitalized patients. Endotoxin of gram-negative bacteria is a pivotal pathogen of sepsis. To understand the effect of endotoxin on hematological aspect and the time course in early childhood, this study was designed with experimental septic model of young rabbits (8 week-old). Rabbits were divided into control (n=7) and endotoxin group (0.50 mg/kg of endotoxin). The endotoxin group was subdivided into six groups by the sampling times: 3, 6, 12, 24, 48 and 72 hr-group (E-G$_{3}$, E-G$_{6}$, E-G$_{12}$, E-G$_{24}$, E-G$_{48}$ and E-G$_{72hrs}$, each n=7). The evaluation of CBC, activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen concentration, coagulation factors and D-dimer were taken from the bloods. The number of leukocytes was lower in E-G$_{3}$ and E-G$_{6hrs}$ (due to pantocytopenia), whereas it was higher in E-G$_{24}$ and E-G$_{48}$ (due to neutrophilia and/or lymphophilia) than in control group (P<0.05). Platelet counts in E-G$_{3}$, E-G$_{6}$, E-G$_{12}$, E-G$_{24}$ and E-G$_{48hrs}$ were lower than those of control group (P<0.05). Normoblast counts in E-G$_{3}$, E-G$_{6}$, E-G$_{12}$, E-G$_{24}$ and E-G$_{48hrs}$ were higher than those of control group (p<0.01). APTT in E-G$_{3}$, E-G$_{6}$, E-G$_{12}$, E-G$_{24}$ and E-G$_{72hrs}$ were longer while PT in E-G$_{3}$, E-G$_{6}$, E-G$_{48}$ and E-G$_{72hrs}$ were higher than those of control group (p<0.05). Fibrinogen concentrations were lower in E-G$_{3}$, E-G$_{6}$ and E-G$_{12}$ but higher in E-G$_{48}$ and E-G$_{72hrs}$ than those of control (p<0.05). Intrinsic coagulation factors (XII, XI, IX, VIII) in all endotoxin groups were significantly lower than those of control group (p<0.05). Extrinsic coagulation factor (X, VII, V, II) were lower in E-G$_{3}$, E-G$_{6}$, E-G$_{12}$ and E-G$_{24hrs}$ whereas they were higher in E-G$_{48}$ and E-G$_{72hrs}$ than in control group (p<0.05). D-dimer concentrations in E-G$_{48}$ and E-G$_{72hrs}$ were higher than those of control group (P<0.001). We concluded that endotoxin led to extensive hematological disturbances including disseminated intravascular coagulation in the young rabbits and that this pathologic condition in the infant and childhood groups will cause the grave results.

• Clinical and Experimental Pediatrics
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• v.48 no.9
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• pp.953-959
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• 2005

Purpose : The administration of total parenteral nutrition(TPN) has become a standard procedure in the management of nutritionally deprived and critically low birth weight neonates. Sepsis remains the most frequent serious complication during TPN, resulting in increased morbidity, mortality and health care costs. This study was performed to evaluate the clinical efficacy and complications of percutaneous central venous catheterization(PCVC) in very low birth weight infants. Methods : A total of 56 very low birth weight infants below 1,500 g during the period from January 1998 to December 2003 were enrolled and their medical records reviewed. Study group(n=32) included the babies who had undergone PCVC and a control group(n=24) included babies who had not undergone PCVC. We compared the study group with the control group for factors such as subject characteristics and catheter-related complications. Results : There was no difference in subject characteristics, such as birth weight, gestational week, respiratory distress syndrome, duration of ventilator therapy, duration from tube to complete oral feeding, days at TPN and its total duration, body weight at discontinuation of TPN and the days taken to reach to 2,000 g. However, the morbidity rate due to patent ductus arterious, chronic lung disease, necrotizing enterocolitis, osteopenia, cholestasis, and sepsis showed no difference. The study group with infants below 1,000 g showed a higher incidence of sepsis compared to the control group of the same weight group. The study group with infants between 1,000 to 1,500 g showed significantly higher incidences of intraventricular hemorrhage and took longer reach the a body weight of 2,000 g. Conclusion : Considering the high incidence of sepsis in the PCVC group, every attempt should be made to minimize the length of TPN therapy and encourage early enteral feeding. We also recommend the use of PCVC carefully in patients requiring prolonged nutritional support.

• KDI Journal of Economic Policy
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• v.12 no.1
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• pp.127-148
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• 1990

A Milgrom-Roberts style signalling model of limit pricing is developed to analyze the possibility and the scope of limit pricing in general, noncooperative oligopolies. The model contains multiple incumbent firms facing a potential entrant and assumes an information asymmetry between incombents and the potential entrant about the market demand. There are two periods in the model. In period 1, n incumbent firms simultaneously and noncooperatively choose quantities. At the end of period 1, the potential entrant observes the market price and makes an entry decision. In period 2, depending on the entry decision of the entrant, n' or (n+1) firms choose quantities again before the game terminates. Since the choice of incumbent firms in period 1 depends on their information about demand, the market price in period 1 conveys information about the market demand. Thus, there is a systematic link between the market price and the profitability of entry. Using Bayes-Nash equilibrium as the solution concept, we find that there exist some demand conditions under which incumbent firms will limit price. In symmetric equilibria, incumbent firms each produce an output that is greater than the Cournot output and induce a price that is below the Cournot price. In doing so, each incumbent firm refrains from maximizing short-run profit and supplies a public good that is entry deterrence. The reason that entry is deterred by such a reduced price is that it conveys information about the demand of the industry that is unfavorable to the entrant. This establishes the possibility of limit pricing by noncooperative oligopolists in a setting that is fully rational, and also generalizes the result of Milgrom and Roberts to general oligopolies, confirming Bain's intuition. Limit pricing by incumbents explained above can be interpreted as a form of credible collusion in which each firm voluntarily deviates from myopic optimization in order to deter entry using their superior information. This type of implicit collusion differs from Folk-theorem type collusions in many ways and suggests that a collusion can be a credible one even in finite games as long as there is information asymmetry. Another important result is that as the number of incumbent firms approaches infinity, or as the industry approaches a competitive one, the probability that limit pricing occurs converges to zero and the probability of entry converges to that under complete information. This limit result confirms the intuition that as the number of agents sharing the same private information increases, the value of the private information decreases, and the probability that the information gets revealed increases. This limit result also supports the conventional belief that there is no entry problem in a competitive market. Considering the fact that limit pricing is generally believed to occur at an early stage of an industry and the fact that many industries in Korea are oligopolies in their infant stages, the theoretical results of this paper suggest that we should pay attention to the possibility of implicit collusion by incumbent firms aimed at deterring new entry using superior information. The long-term loss to the Korean economy from limit pricing can be very large if the industry in question is a part of the world market and the domestic potential entrant whose entry is deterred could .have developed into a competitor in the world market. In this case, the long-term loss to the Korean economy should include the lost opportunity in the world market in addition to the domestic long-run welfare loss.

• Clinical and Experimental Pediatrics
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• v.45 no.8
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• pp.967-972
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• 2002

Purpose : A retrospective study was undertaken to evaluate the usefulness of low risk criteria for identifying febrile infants younger than three months unlikely to have serious bacterial infection. Methods : We conducted a retrospective study of 527 infants younger than three month with a axillary temperature ${\geq}37.4^{\circ}C$. If they met the following all four criteria, appear well, WBC $5,000-20,000/mm^3$, urine stick WBC(-) and nitrite(-), CSF WBC < $10/mm^3$, they were considered at low risk for serious bacterial infection(SBI). SBI was defined as a positive culture of urine, blood, or cerebrospinal fluid. The sensitivity, specificity, negative predictive value and positive predictive value of the low risk criteria were calculated. Results : Of 527 febrile infants, 110(21.0%) had serious bacterial infections. The 2.7% who met the low risk criteria had SBI and negative predictive value was 97.3%. SBI was diagnosed in 103 infants(38.6%) who didn't meet the low risk criteria including urinary tract infection(78.6%), most commonly, bacteremia(16.5%), bacterial meningitis(8.7%), Salmonella gastroenteritis(1%), osteomyelitis( 1%), septic arthritis of hip joint(1%). There were no differences in the sensitivity and negative predictive value according to the monthly-age-group. Conclusion : This low risk criteria to identify infants unlikely to have SBI early is available, however low risk infants must be carefully observed.

• Pediatric Infection and Vaccine
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• v.27 no.2
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• pp.102-110
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• 2020

Purpose: This study aimed to investigate the clinical characteristics of human parechovirus (HPeV) infection in sepsis-like syndrome in infants aged under 3 months. Methods: Medical records of infants aged under 3 months with sepsis-like symptoms who were admitted between July 1, 2018 and August 31, 2018 were reviewed. A multiplex reverse transcription-polymerase chain reaction panel test was performed on the cerebrospinal fluid (CSF). Thirty-nine enrolled infants were categorized into three groups: 11 in group 1 (HPeV detected in the CSF), 13 in group 2 (enterovirus detected in the CSF), and 15 in group 3 (no virus detected in the CSF). Results: Compared with groups 2 and 3, a higher proportion of group 1 had tachycardia, tachypnea, apnea, and hypotension (P<0.05). A significantly lower white blood cell (WBC) count was noted in group 1 than in groups 2 and 3 (5,622±2,355/μL, 9,397±2,282/μL, and 12,312±7,452/μL, respectively; P=0.005). The CSF WBC count was lower in group 1 than in groups 2 and 3 (0.9±1.7/μL, 85.1±163.6/μL, and 3.7±6.9/μL, respectively; P=0.068). The proportion of patients requiring inotrope support (36.6% vs. 0% and 6.6%), mechanical ventilation (18.1% vs. 0% and 0%), and high flow nasal cannula (45.4% vs. 15.3% and 6.6%) was higher in group 1 than in groups 2 and 3. All patients recovered completely without complications. Conclusions: HPeV infection shows a severe clinical course and can cause a severe sepsis-like syndrome in infants aged under 3 months. Early diagnosis and proper treatment of HPeV infection are required.

• Korean Journal of Child Education & Care
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• v.18 no.2
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• pp.85-102
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• 2018

The purpose of this study is to determine the working conditions and demands of the assistant workforce at childcare centers, and to provide suggestions on policies for childcare teachers. To achieve the purpose of the study, a total of 190 assistant teachers, nursing helpers, alternative teachers and others were surveyed online during the month of August 2017. The survey examined the employment route and working motives, working conditions and environment, job and educational difficulties for analyzing the work conditions and demands of ancillary staff. For the analysis method, SPSS 12.0 was used to analyze frequency and difference. The main findings are as follows. First, childcare center assistants were able to work at their respective times, making it mandatory for them to enter the workforce, and making job openings for ancillary teachers. Second, 73.7% said the daily working hours were '4 hours to 8 hours' under the conditions and 57.9% said 'More than 510,000 won to less than 1 million won.' Average amount of rest time per day was about 30 minutes, and 17% had no rest periods. Third, based on the job and education status, ancillary personnel performed "infant and child guidance and interaction", "Cleaning and cleanliness related tasks" most actively, and "care for cleaning and cleanliness" and "care for morning and night care". Fourth, in the job trouble and difficulty, ancillary staff found it difficult to satisfy with wage related complaints and job insecurity, and the reason for agreeing to the non-regular workforce becoming a regular worker was found to be due to the stability of employment. Lastly, the most urgent tasks to solve the problem of non-regular workers were to fill the wage gap between regular and irregular workers, shorten the working hours and improve the working conditions. The policy implications are presented based on the above findings.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.8 no.2
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• pp.157-163
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• 2005

Purpose: Dietary protein induced proctocolitis (DPIPC) can be considered as a cause of rectal bleeding or blood streaked stool in otherwise healthy-looking infants in the first several months of life. Failure to appreciate this entity may lead to inappropriate diagnostic or therapeutic intervention. This study aimed to ascertain the clinical features, treatment and prognosis of DPIPC. Methods: We reviewed 13 infants retrospectively, presented with bloody stool in early infancy. They were diagnosed as DPIPC clinically in Pusan National University Hospital from May 2002 to June 2004. Results: Seven males and six females were included. The mean age at onset of bleeding was $96.8{\pm}58.8days$. The mean frequency of hematochezia was $2.6{\pm}2.5$ times a day. Duration from onset of symptom to diagnosis was $35.5{\pm}55.0days$ and duration from onset of symptom to resolution of bleeding was $58.7{\pm}67.0days$. Nine (69.2%) were exclusively breast-fed infants and two (15.4%) were formula-fed infants. All but one infant did not have family history of other allergic diseases. A dietary history of ingestion of cow's milk, nut or shellfish was present in three mothers. Peripheral eosinophil count was normal to slightly elevated (total WBC count $10,555{\pm}3,145/mm^3$, relative eosinophil count $6.3{\pm}3.0%$, absolute eosinophil count $659.0{\pm}532.2/mm^3$). Sigmoidoscopy revealed lymphonodular hyperplasia with surrounding hemorrhagic spots in the rectosigmoid colon in 6 infants. Histopathologic finding of colonic biopsies in 5 infants showed chronic inflammation with lymphoid follicular hyperplasia (5 infants), crypt abscess (3 infants), or mild infiltration of eosinophils (less than 20/high power field) in the lamina propria. Spontaneous resolution of rectal bleeding occurred in all infants without dietary change or medicine. Conclusion: Most infants with DPIPC experience a very benign course and have spontaneous resolution of rectal bleeding without changes in the mother's diet. In the case of strong evidence for DPIPC we suggest deferring further invasive investigation and continuing breast feeding.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.2
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• pp.116-121
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• 2008

Purpose: Cricopharyngeal incoordination is a rare cause of swallowing difficulties in newborns and infants; it is characterized by delayed pharyngeal contractions related to cricopharyngeal relaxation. Dysphagia and repeated aspiration are common findings despite normal sucking. We conducted this study to assess the clinical features of cricopharyngeal incoordination in newborns and infants. Methods: An analysis of the clinical data from 17 patients with cricopharyngeal incoordination who were admitted to the Department of Pediatrics, Pusan National University Hospital, between 2000 and 2006 was conducted retrospectively. The diagnosis of cricopharyngeal incoordination was established by the clinical characteristics and the videofluoroscopic swallowing studies. Results: The male to female ratio was 1:1.1 (males 8, females 9) the age range 1 to 60 days. The body weight of 11 patients (64.7%) was less than the $10^{th}$ percentile at diagnosis. Six patients (35.3%) were born prematurely. The associated anomalies or diseases were chromosomal anomaly (2 cases), congenital heart disease (3 cases), and laryngomalacia, hypoxic brain damage or neonatal seizures (1 case each). The chief complaints of patients were recurrent aspiration pneumonia (10 cases), feeding difficulty (9 cases), dyspnea (4 cases), and chocking (4 cases). The severity of aspiration on the videoesophagogram or esophagogram was mild in 12 cases. The correlation between the severity of aspiration and the duration of tube feeding after the diagnosis was significant (p<0.05). Conclusion: Cricopharyngeal incoordination should be considered in the differential diagnosis of newborns and infants, without known risk factors associated with swallowing dysfunction, when they present with unexplained respiratory problems. Although the prognosis of cricopharyngeal incoordination is good, early diagnosis and tube feeding are recommended to prevent the complications associated with this disorder.

• Neonatal Medicine
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• v.16 no.2
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• pp.190-196
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• 2009

Purpose: Candida infection has increased in neonatal intensive care units (NICU). However, recent reports on systemic candida infections in preterm newborns are rare in Korea. The aim of this study was to examine the epidemiological features of systemic candida infection in very low birth weight infants (VLBW) over the past five years. Methods: We retrospectively reviewed the medical records of 19 patients with systemic candida infections in VLBW that were admitted to the neonatal intensive care units of three hospitals affiliated with the College of Medicine, The Catholic University of Korea from January 2004 to December 2008. We analyzed the birth weight, gestational age, age at diagnosis, risk factors, co-morbidity, antifungal treatment, and mortality rates among the 19 patients. Results: Systemic candida infections occurred in 19 cases (4.7%) among the VLBW infants. The mean birth weight and gestational age were 959.0$\pm$255.9 g and 26.7$\pm$2.1 weeks. The isolated Candida species were C. albicans (4), C. parapsilosis (9), C. glabrata (2), C. famata (2), and unkown subspecies (2). Most patients had various associated risk factors, including a central venous catheter, broad spectrum antibiotics, parenteral nutrition, intravenous lipid emulsion, endotracheal intubation and $H_2$ blocker therapy. There was no significant difference in the risk factors between newborns that survived and those that died with regard to the systemic candida infection, except for gestational age. Nine (47.4%) out of 19 patients with a candida infection died and four cases (21.2%) were directly related to the candida infection. Conclusion: The prevalence of systemic candida infection is increasing in VLBW infants. The majority of Candida species has shifted to C. non-albicans, especially C. parapsilosis. Because of the high mortality associated with candida infection in the NICU, prophylaxis and early treatment based on epidemiological features is necessary.

• Clinical and Experimental Pediatrics
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• v.53 no.3
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• pp.380-391
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• 2010

Purpose : Respiratory syncytial virus (RSV) is one of the main pathogens causing lower respiratory infections (LRI) in young children, usually of limited severity. However, in congenital heart disease (CHD) patients, one of the high-risk groups for RSV infection, RSV can cause serious illnesses and fatal results. To elucidate the effects of RSV infection in CHD patients, we observed RSV infection cases among CHD patients and non-CHD patients. Methods : On admission of 343 LRI patients over 3 years, 77 cases of RSV infection were detected by the RSV antigen rapid test of nasopharyngeal secretion. We compared RSV infection cases among groups of CHD and non-CHD patients. Results : During the winter season, RSV caused 20-0% of LRI admissions in children. In patients with completely repaired simple left to right (L-R) shunt diseases such as ventricular septal defect, atrial septal defect, and patent ductus arteriosus, RSV infections required short admission days similar to non-CHD patients. In patients with repaired CHD other than simple L-R shunt CHD, for whom some significant hemodynamic problems remained, RSV infection required long admission days with severe clinical course. In children with unrepaired CHD, RSV infection mostly occurred in early infant age, with long admission days. RSV infections within a month after cardiac surgery also required long admission days and severe clinical course. Conclusion : To avoid the tragedic outcome of severe RSV infection in the CHD patients, efforts to find the subgroups of CHD patients at high risk to RSV infection are needed, and effective preventive treatment should be applied.