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Background: According to international pediatric urinary tract infection (UTI) guidelines, selecting ampicillin/ sulbactam or amoxicillin/clavulanate is recommended as the first-line treatment for pediatric UTI. In Korea, elevated resistance to ampicillin and ampicillin/sulbactam has resulted in the widespread use of third-generation cephalosporins for treating pediatric UTIs. This study aims to compare the efficacy of piperacillin-tazobactam (TZP) and cefotaxime (CTX) as first-line treatments in hospitalized children with UTIs. Materials and Methods: The study, conducted at Jeju National University Hospital, retrospectively analyzed medical records of children hospitalized for febrile UTIs between 2014 and 2017. UTI diagnosis included unexplained fever, abnormal urinalysis, and the presence of significant uropathogens. Treatment responses, recurrence, and antimicrobial susceptibility were assessed. Results: Out of 323 patients, 220 met the inclusion criteria. Demographics and clinical characteristics were similar between TZP and CTX groups. For children aged ≥3 months, no significant differences were found in treatment responses and recurrence. Extended-spectrum beta-lactamase (ESBL)-positive strains were associated with recurrence in those <3 months. Conclusion: In Korea, escalating resistance to empirical antibiotics has led to the adoption of broad-spectrum empirical treatment. TZP emerged as a viable alternative to CTX for hospitalized children aged ≥3 months with UTIs. Consideration of ESBL-positive strains and individualized approaches for those <3 months are crucial. [ABSTRACT FROM AUTHOR]

This article provides a systematic review and meta-analysis of studies on the efficacy and safety of COVID-19 vaccines in adolescents. The review found that vaccination in adolescents was effective in preventing COVID-19 infection, although the effectiveness was lower in observational studies compared to randomized controlled trials. The analysis also showed that there was a higher incidence of myocarditis and/or pericarditis after vaccination, particularly in males and after the second dose. The study concluded that mRNA COVID-19 vaccines were effective and safe in adolescents, but monitoring of adverse events should continue. [Extracted from the article]

Coronavirus disease 2019 (COVID-19) is a mild to moderate respiratory illness in most children and adolescents, but a small proportion develop severe or critical illness. Although pediatric clinical trials for the treatment of COVID-19 are sparse, there are some available drugs for children and adolescents with severe COVID-19. This review summarizes clinical data focusing on antiviral agents and immunomodulators for COVID-19 treatment. Additionally, the current recommendations for therapeutics for children and adolescents with COVID-19 are discussed. Remdesivir is suggested for pediatric patients with COVID-19 in the following cases: children and adolescents with severe COVID-19 who need supplemental oxygen without mechanical ventilation; adolescents aged ≥12 years and weight of at least 40 kg with COVID-19 who do not require supplemental oxygen and are within 7 days of symptom onset and are at high risk of progression to severe illness. Nirmatrelvir/ritonavir is considered for adolescents aged ≥12 years and weighing at least 40 kg who do not require supplemental oxygen and are within 5 days of symptom onset and are at high risk of progression to severe disease. Corticosteroids are not recommended in children and adolescents with mild to moderate COVID-19. Corticosteroids are recommended in children and adolescents with severe to critical COVID-19. [ABSTRACT FROM AUTHOR]

배경 In a randomized controlled trial, the BNT162b2 mRNA vaccine (tozinameran, Pfizer-BioNTech) showed 95% or greater efficacy against symptomatic and severe COVID-19 disease due to SARS-CoV-2. In a randomized controlled trial, the BNT162b2 mRNA vaccine (tozinameran, Pfizer-BioNTech) showed 95% or greater efficacy against symptomatic and severe COVID-19 disease due to SARS-CoV-2. However, BNT162b2 mRNA vaccine effectiveness against infections of the delta variant declined from 93% in first month to 53% after 4 months after fully vaccination. Although the preventive efficacy of vaccines has been confirmed in clinical trials, it has not been evaluated at the community level. In addition, it is possible that the efficacy of vaccines will be lower against new strains as they spread globally. Herein, we performed a prospective observational study of health care workers to assess the SARS-CoV-2 anti- body response after second dose BNT162b2 mRNA COVID-19 vaccination in a single hospital, South Korea. 방법 In prospective observational study, we analyzed SARS-CoV-2 antibodies response about healthcare work- ers at COVID-19 related departments after each first dose and second dose BNT162b2 mRNA COVID-19 vaccination in a single hospital which is designated to infectious disease, South Korea. The study participants were eligible to healthcare workers of this hospital between 01 March 2021 and 11 October 2021. The participants consisted of doctors, nurses, and technicians of departments of laboratory medi- cine and radiology. Total 1,672 healthcare workers were eligible for the SARS CoV-2 vaccination; 256 participants were enrolled in the study. Of the participants, 253 participants were sampled as baseline antibody test in 9 March 2021, 249 participants were completed the fully vaccination, and they had not a S-IgG at baseline test. Blood samples were collected from the participants at the department of laboratory medicine in Jeju National University Hospital. A 10mL blood sample was collected four times from each participant in three serum-separating tubes; visit 1 (within 1 week before first dose vacci- nation), visit 2 (4 weeks after first dose vaccination), visit 3 (3 months after second dose vaccination), and visit 4 (6 months after second dose vaccination). All participants provided written informed consent. A total of 982 samples were obtained and analyzed in parallel using the Alinity I SARS-CoV-2 IgG II Quant assay (Abbott Ireland Diagnostics Division, Sligo,Ireland). In addition, the SARS-CoV-2 IgG II Quant assay is used to aid in the diagnosis of SARS-CoV-2 infection in conjunction with clinical presentation, the assay can also be used to evaluate the immune status of infected individuals and to monitor antibodyresponses in individuals who have received a COVID-19 vaccine, by quantitatively measuring IgG antibodies against the S receptor-binding domain (RBD) of SARS-CoV-2 (S-IgG). IgG antibody levels < 50 AU/mL were considered nonprotective for this test. 결과 A total of 249 participants were enrolled in this study and 982 blood samples were analyzed. The mean age was 38.1 ± 9.5 years, and the female was 145 (58.2%). Of total participants, 166 (66.7%) subjects had positive nAbs (inhibition rates ≥ 20%) at visit 2, 237 (97.5%) subjects had nAb among 243 subjects at visit 3, and 150 subjects (63.3%) had positive nAb among 237 subjects at visit 4. In analysis of S-IgG, the levels of median quantitative antibody were 1275.1 AU/mL (IQR 755.5-2,119.0) at visit 2, 2,765.9 AU/mL (IQR 1,809.8-4138.4) at visit 3, and 970.1 AU/mL (IQR 606.0-1,495.9) at visit 4, respectively. At visit 1, 246 (98.8%) subjects had positive S-IgG (≥50AU/mL), and all participants had positive antibody levels at visit 3 and 4 after fully vaccinated. The characteristics of patients such as age, body mass index, and comorbidity had no relationship with nAbs or S-IgG at all visits. Considering the change of antibody by time, both nAbs and S-IgG at visit 4 were decreased compared to visit 3. The evidence of SARS-CoV-2 infection was not found among all participants till the end of the study. 결론 BNT162b2 mRNA vaccine was effective to protect in healthy healthcare workers at the COVID-19 related departments. The S-IgG maintained well and nAb was waning in six months after fully vacci- nation, this result showed the need for boost shot vaccination in some healthcare workers in six months after fully vaccination. Herein, we suggest that we need further studies for boost shot vacci- nation in low prevalence countries and various population. [ABSTRACT FROM AUTHOR]

Purpose: Urinary tract infections (UTIs) are the most common and serious bacterial infections in children. Therefore, early diagnosis of vesicoureteral reflux (VUR) for treatment planning and the identification of noninvasive markers that can predict renal injury are important in patients with UTIs. We analyzed the clinical features of pediatric UTIs commonly encountered by general practitioners and reinterpreted the blood tests and imaging findings to identify the important clinical predictive markers of VUR in order to selectively perform VCUG. Methods: This retrospective study was performed among 183 children diagnosed with a UTI or acute pyelonephritis. Results: The most significant predictor of high grade and bilateral VUR identified using area under the curve analyses was hydronephrosis on kidney ultrasound images with renal cortical defects on dimercaptosuccinic acid (DMSA) kidney scan simultaneously, followed by hydronephrosis only on kidney ultrasound. Conclusion: The presence of hydronephrosis on kidney ultrasound images or cortical defects or asymmetric kidneys on the DMSA kidney scans can be predictive markers of VUR, reducing the need for VCUG. Our study can thus help minimize the exposure to radiation among patients through selective VCUG. [ABSTRACT FROM AUTHOR]

Purpose: On the basis of evidence, we aimed to reevaluate the necessity of the empirical proton pump inhibitor (PPI) trial for children with suspected gastroesophageal reflux disease (GERD). Methods: We analyzed the frequency of GERD in 85 school-age children with gastroesophageal reflux (GER) symptoms, who received 24-hour esophageal pH monitoring and/or upper endoscopy. According to the reflux index (RI), the children were classified into normal (RI <5%), intermediate (5%≤ RI <10%), or abnormal (RI ≥10%) groups. Results: Fifty six were female and 29 were male. Their mean age was 12.6±0.5 (±standard deviation) years (range: 6.8–18.6). The RI analysis showed that the normal group included 76 patients (89.4%), the intermediate group included 6 patients (7.1%), and the abnormal group included 3 patients (3.5%). The DeMeester score was 5.93±4.65, 14.68±7.86 and 40.37±12.96 for the normal, intermediate and abnormal group, respectively (p=0.001). The longest reflux time was 5.56±6.00 minutes, 9.53±7.84 minutes, and 19.46±8.35 minutes in the normal, intermediate, and abnormal group, respectively (p=0.031). Endoscopic findings showed reflux esophagitis in 7 patients. On the basis of the Los Angeles Classification of Esophagitis, 5 of these patients were included in group A, 1 patient, in group B and 1 patient, in group C. Conclusion: The incidence of GERD was very low in school-age children with GER symptoms. Therefore, injudicious diagnostic PPI trials would be postponed until the actual prevalence of GERD is verified in future prospective studies. [ABSTRACT FROM AUTHOR]

Staphylococcal scalded skin syndrome (4S) is an exfoliative skin disease caused by Staphylococcus aureus toxins. 4S usually has a benign course in young infants and children; however, it could be fatal in preterm infants, especially very low birth weight infants. We experienced two sequential 4S cases that occurred in the neonatal intensive care unit. One of the patients had complications such as bacteremia and acute kidney injury. [ABSTRACT FROM AUTHOR]

The incidence of symptomatic thrombosis of umbilical arterial catheterization is 1-3%. Therapeutic options may include: using heparin or low molecular weight heparin, using a thrombolytic agent, or surgical thrombectomy. However, there are insufficient data to recommend any one treatment over the others. Recently, enoxaparin, a low molecular weight heparin, has emerged as a drug of choice for the treatment of neonatal thrombosis due to pharmacologic stability over unfractionated heparin or thrombolytic agents. We report a case of successful treatment of aortic thrombosis after umbilical arterial catheterization with enoxaparin in preterm infants. [ABSTRACT FROM AUTHOR]

Purpose: Streptococcus pyogenes is an important cause of invasive diseases in children. We aimed to describe the clinical characteristics of invasive infections due to S. pyogenes in children in Korea. Methods: A retrospective study of children under 18 years of age with invasive infections due to S. pyogenes at Seoul National University Children's Hospital between March 1992 and December 2012, and Seoul National University Bundang Hospital between March 2003 and December 2012 was conducted. Demographic factors, clinical characteristics, laboratory findings, treatment, mortality and morbidity of all patients were reviewed. Results: A total of 30 among 36 cases identified as invasive disease due to S. pyogenes were available for review. There was a predominance for male subjects (male:female=2.75:1). The median age was 50 months (range 12 days to 15 years) and 53.3% were under 5 years of age. Skin and soft tissue infections (9/30, 30.0%), bacteremia without identified focus (4/30, 13.3%) and bone and joint infections (6/30, 20.0%) were the most frequent clinical presentations. Streptococcal toxic shock syndrome (3/30, 10.0%) pulmonary, abdomen and central nervous system infections (2/30, 6.7%) were also seen. There was a peak in number of patients in year 2012 (9/30, 30.0%). There were no cases of mortality. Erythromycin and clindamycin resistance rates were low by 3.8% and 7.5%, respectively. Conclusion: We studied the clinical presentations of invasive infections due to S. pyogenes during the past 20 years in Korean children. The findings of this study help us understand the characteristics of the disease, enhancing early recognition and prompting adequate antibiotic therapy which is important in reducing morbidity and mortality. [ABSTRACT FROM AUTHOR]

Hemolytic uremic syndrome (HUS) is one of the most common causes of acute renal failure in childhood and is primarily diagnosed in up to 4.5% of children who undergo chronic renal replacement therapy. Escherichia coli serotype O157:H7 is the predominant bacterial strain identified in patients with HUS; more than 100 types of Shiga toxin-producing enterohemorrhagic E. coli (EHEC) subtypes have also been isolated. The typical HUS manifestations are microangiopathic hemolytic anemia, thrombocytopenia, and renal insufficiency. In typical HUS cases, more serious EHEC manifestations include severe hemorrhagic colitis, bowel necrosis and perforation, rectal prolapse, peritonitis, and intussusceptions. Colonic perforation, which has an incidence of 1-2%, can be a fatal complication. In this study, we report a typical Shiga toxin-associated HUS case complicated by small intestinal perforation with refractory peritonitis that was possibly because of ischemic enteritis. Although the degree of renal damage is the main concern in HUS, extrarenal complications should also be considered in severe cases, as presented in our case. [ABSTRACT FROM AUTHOR]

In Korea, Mycoplasma pneumoniae was detected in 255/2,089 respiratory specimens collected during 2000-2011; 80 isolates carried 23S rRNA gene mutations, and 69/123 culture-positive samples with the mutation were resistant to 5 macrolides. During 2000-2011, prevalence of the mutation increased substantially. These findings have critical implications for the treatment of children with mycoplasma pneumonia. [ABSTRACT FROM AUTHOR]

MnO2 was added to 0.75Pb(Zr0.47Ti0.53)O3–0.25Pb(Zn1/3Nb2/3)O3 (0.75PZT–0.25PZN) ceramics in order to make a high-power piezoelectric material. The Mn4+ ion produced a defect dipole consisting of an Mn4+ ion and an oxygen vacancy that transformed the 0.75PZT–0.25PZN ceramics into hard materials. The Qm value significantly increased with the addition of MnO2 and reached a value of 1680 for the 1.5 mol% MnO2-added 0.75PZT–0.25PZN ceramic. Moreover, this specimen exhibited a high kp of 0.53 with a ℇ3T/ℇ0 of 1518. Additionally, the 1.5 mol% MnO2-added 0.75PZT–0.25PZN ceramics sintered at 900°C for 4 h also exhibited high piezoelectric properties of Qm=1115, kp=0.50, and ℇ3T/ℇ0=1537. [ABSTRACT FROM AUTHOR]

Objectives: Clevudine has demonstrated antiviral potency in the treatment of naïve chronic hepatitis B patients in pivotal studies. The objectives of this study were to evaluate the safety and efficacy of a 1-year treatment with clevudine in chronic hepatitis B patients. Methods: This is a post-marketing surveillance using case report forms which were submitted to the health authorities. Results: Analysis of individual data showed that hepatitis B virus (HBV) DNA after a 1-year treatment was <141,500 copies/ml in 96% of hepatitis B e antigen (HBeAg)-positive and 100% of HBeAg-negative patients. The proportion of patients with HBV DNA <2,000 copies/ml after a 1-year treatment was 74%: 71% of HBeAg-positive and 93% of HBeAg-negative patients. Most of the patients with HBV DNA below the detection limit with each assay at week 24 showed sustained viral suppression up to week 48. The proportion of patients who showed normal alanine aminotransferase at week 48 was 86% in HBeAg-positive patients and 87% in HBeAg-negative patients. The rates of HBeAg-loss were 21%. Two patients showed viral breakthrough during treatment. Conclusion: Clevudine monotherapy demonstrates potent antiviral activity as well as biochemical and serological response with a 0.7% rate of viral breakthrough in naïve chronic hepatitis B patients. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

(Na0.5K0.5)NbO3 (NKN) ceramic with 1.5 mol% CuO added (NKNC) was well sintered even at a low temperature of 900°C with the addition of ZnO. Most of the ZnO reacted with the CuO and formed the liquid phase that assisted the densification of the specimens at 900°C. A few Zn2+ ions entered the matrix of the specimens and increased the coercive field ( Ec) and Qm values of the specimens. High-piezoelectric properties of kp=0.37, Qm=755, and ℇ3 T/ℇ0=327 were obtained from the NKNC ceramics containing 1.0 mol% ZnO sintered at 900°C for 2 h. [ABSTRACT FROM AUTHOR]

Li2CO3 was added to Mg2V2O7 ceramics in order to reduce the sintering temperature to below 900°C. At temperatures below 900°C, a liquid phase was formed during sintering, which assisted the densification of the specimens. The addition of Li2CO3 changed the crystal structure of Mg2V2O7 ceramics from triclinic to monoclinic. The 6.0 mol% Li2CO3-added Mg2V2O7 ceramic was well sintered at 800°C with a high density and good microwave dielectric properties of ℇr=8.2, Q× f=70 621 GHz, and τf=−35.2 ppm/°C. Silver did not react with the 6.0 mol% Li2CO3-added Mg2V2O7 ceramic at 800°C. Therefore, this ceramic is a good candidate material in low-temperature co-fired ceramic multilayer devices. [ABSTRACT FROM AUTHOR]

V2O5 was added to ceramics of nominal composition Zn1.8SiO3.8 (ZS) in order to decrease their sintering temperature for application to low-temperature cofired ceramic devices. For the specimens sintered at 875°C, a dense microstructure was developed when the V2O5 content exceeded 9.0 mol% due to the presence of the liquid phase containing SiO2 and V2O5. The microwave dielectric properties of the ZS ceramics were influenced by the V2O5 content. Good microwave dielectric properties of Q× f=17 500 GHz, ℇr=7.3, and τf=−28 ppm/°C were obtained from the specimen containing 12.0 mol% V2O5 sintered at 875°C for 2 h. [ABSTRACT FROM AUTHOR]

In order to determine the most suitable type of dye for soya bean fibre, the dyeing properties of three acid dyes and three bifunctional reactive dyes were compared. Additionally, the effect of a range of reactive groups on dyeing performance were studied, including difluorochloropyrimidine, monofluorotriazine, monochlorotriazine and β-sulphatoethyl sulphone, and of these the first was found to perform best. Irrespective of reactive group, however, the main factor affecting build-up was found to be the substantivity of the dye for soya fibre. The monofunctional reactive dyes in general were found to exhibit good wash fastness. [ABSTRACT FROM AUTHOR]

Drop-on-demand ink-jet inks made from dyes generally show poor light and wet fastness. A number of studies have been carried out previously to improve the fastness of such inks by introducing novel dyes and new additives. Based on the research results, use of fast dyes could give ink-jet inks with good properties. This study describes new black dyes for aqueous ink-jet inks, which show better light and wet fastness and print quality, compared to an analogous ink formulated from C1 Food Black 2. [ABSTRACT FROM AUTHOR]