Background: Malaria elimination strategies in the Republic of Korea (ROK) have decreased malaria incidence but face challenges due to delayed case detection and response. To improve this, machine learning models for predicting malaria, focusing on high-risk areas, have been developed. Methods: The study targeted the northern region of ROK, near the demilitarized zone, using a 1-km grid to identify areas for prediction. Grid cells without residential buildings were excluded, leaving 8,425 cells. The prediction was based on whether at least one malaria case was reported in each grid cell per month, using spatial data of patient locations. Four algorithms were used: gradient boosted (GBM), generalized linear (GLM), extreme gradient boosted (XGB), and ensemble models, incorporating environmental, sociodemographic, and meteorological data as predictors. The models were trained with data from May to October (2019–2021) and tested with data from May to October 2022. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC). Results: The AUROC of the prediction models performed excellently (GBM = 0.9243, GLM = 0.9060, XGB = 0.9180, and ensemble model = 0.9301). Previous malaria risk, population size, and meteorological factors influenced the model most in GBM and XGB. Conclusion Machine-learning models with properly preprocessed malaria case data can provide reliable predictions. Additional predictors, such as mosquito density, should be included in future studies to improve the performance of models.

Purpose: We aimed to assess the humoral response to and reactogenicity of coronavirus disease 2019 (COVID-19) vaccination according to the vaccine type and to analyze factors associated with immunogenicity in actively treated solid cancer patients (CPs). Materials and Methods: Prospective cohorts of CPs, undergoing anticancer treatment, and healthcare workers (HCWs) were established. The participants had no history of previous COVID-19 and received either mRNA-based or adenovirus vector–based (AdV) vaccines as the primary series. Blood samples were collected before the first vaccination and after 2 weeks for each dose vaccination. Spike-specific binding antibodies (bAbs) in all participants and neutralizing antibodies (nAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wild-type, Delta, and Omicron variants in CPs were analyzed and presented as the geometric mean titer. Results: Age-matched 20 HCWs and 118 CPs were included in the analysis. The bAb seroconversion rate and antibody concentrations after the first vaccination were significantly lower in CPs than in HCWs. After the third vaccination, antibody levels in CPs with a primary series of AdV were comparable to those in HCWs, but nAb titers against the Omicron variant did not quantitatively increase in CPs with AdV vaccine as the primary series. The incidence and severity of adverse reactions post-vaccination were similar between CPs and HCWs. Conclusion CPs displayed delayed humoral immune response after SARS-CoV-2 vaccination. The booster dose elicited comparable bAb concentrations between CPs and HCWs, regardless of the primary vaccine type. Neutralization against the Omicron variant was not robustly elicited following the booster dose in some CPs, implying the need for additional interventions to protect them from COVID-19.

Background: Pediatric urinary tract infection (UTI) caused by extended-spectrum β-lactamase (ESBL)-positive gram-negative bacilli (GNB) has limited options for oral antibiotic treatment. The purpose of this study was to investigate the susceptibility of ESBLpositive Escherichia coli and Klebsiella pneumoniae isolates from pediatric urine samples to two oral antibiotics (fosfomycin and nitrofurantoin). Methods: From November 2020 to April 2022, ESBL-positive E. coli and K. pneumoniae isolates from urine samples were collected at Samsung Medical Center, Seoul, Korea. Patients over 18 years of age or with malignancy were excluded. For repeated isolates from the same patient, only the first isolate was tested. Minimum inhibitory concentrations (MICs) were measured using agar (fosfomycin) or broth (nitrofurantoin) dilution methods. MIC 50 and MIC 90 were measured for fosfomycin and nitrofurantoin in both E. coli and K. pneumoniae. Results: There were 117 isolates from 117 patients, with a median age of 7 months (range, 0.0–18.5 years). Among 117 isolates, 92.3% (108/117) were E. coli and 7.7% (9/117) were K. pneumoniae. Isolates from the pediatric intensive care unit (PICU) and general ward (GW) was 11.1% (13/117) and 88.9% (104/117), respectively. Among 108 E. coli isolates, MIC 50 and MIC 90 for fosfomycin were 0.5 μg/mL and 2 μg/mL, respectively. Fosfomycin susceptibility rate was 97.2% (105/108) with a breakpoint of 128 μg/mL. Fosfomycin susceptibility rate was significantly lower in PICU isolates than in GW isolates (81.8% vs. 99.0%, P = 0.027).For nitrofurantoin, both the MIC 50 and MIC 90 were 16 μg/mL. Nitrofurantoin susceptibility rate was 96.3% (104/108) with a breakpoint of 64 μg/mL based on Clinical and Laboratory Standards Institute guidelines. Among the nine K. pneumoniae isolates, the MIC 50 and MIC 90 for fosfomycin was 2 μg/mL and 32 μg/mL, respectively. MIC 50 and MIC 90 for nitrofurantoin were 64 μg/mL and 128 μg/mL, respectively. Conclusion For uncomplicated UTI caused by ESBL-positive GNB in Korean children, treatment with fosfomycin and nitrofurantoin for E. coli infections can be considered as an effective oral therapy option.

Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury without any association with preceding diarrhea. Dysregulation of the complement system is the most common cause of aHUS, and monoclonal humanized anti-C5 antibodies are now recommended as the first-line treatment for aHUS. However, if the complement pathway is not the cause of aHUS, C5 inhibitors are ineffective. In this study, we report the second reported case of aHUS caused by DGKE mutations in Republic of Korea. The patient was an 11-month-old infant who presented with prodromal diarrhea similar to typical HUS, self-remitted with conservative management unlike complement-mediated aHUS but recurred with fever. While infantile aHUS often implies genetic dysregulation of the complement system, other rare genetic causes, such as DGKE mutation, need to be considered before deciding long-term treatment with C5 inhibitors.

Plasmodium vivax exhibits dormant liver-stage parasites, called hypnozoites, which can cause relapse of malaria. The only drug currently used for eliminating hypnozoites is primaquine. The antimalarial properties of primaquine are dependent on the production of oxidized metabolites by the cytochrome P450 isoenzyme 2D6 (CYP2D6). Reduced primaquine metabolism may be related to P. vivax relapses. We describe a case of 4 episodes of recurrence of vivax malaria in a patient with decreased CYP2D6 function. The patient was 52-year-old male with body weight of 52 kg. He received total gastrectomy and splenectomy 7 months before the first episode and was under chemotherapy for the gastric cancer. The first episode occurred in March 2019 and each episode had intervals of 34, 41, and 97 days, respectively. At the first and second episodes, primaquine was administered as 15 mg for 14 days. The primaquine dose was increased with 30 mg for 14 days at the third and fourth episodes. Seven gene sequences of P. vivax were analyzed and revealed totally identical for all the 4 samples. The CYP2D6 genotype was analyzed and intermediate metabolizer phenotype with decreased function was identified.

Purpose: Under the South Korea’s unique health insurance structure, any new surgical technology must be evaluated first by the government in order to consider whether that particular technology can be applied to patients for further clinical trials as categorized as ‘New Health Technology,’ then potentially covered by the insurance sometime later. The aim of this meta-analysis was to assess the safety and efficacy of transanal total mesorectal excision (TaTME) for rectal cancer, activated by the National Evidence-based Healthcare Collaborating Agency (NECA) TaTME committee. Methods: We systematically searched Ovid-MEDLINE, Ovid-Embase, Cochrane, and Korean databases (from their inception until August 31, 2019) for studies published that compare TaTME with laparoscopic total mesorectal excision (LaTME). End-points included perioperative and pathological outcomes. Results: Sixteen cohort studies (7 for case-matched studies) were identified, comprising 1,923 patients (938 TaTMEs and 985 LaTMEs). Regarding perioperative outcomes, the conversion rate was significantly lower in TaTME (risk ratio, 0.19; 95% confidence interval, 0.11–0.34; P < 0.001); whereas other perioperative outcomes were similar to LaTME. There were no statistically significant differences in pathological results between the 2 procedures. Conclusion Our meta-analysis showed comparable results in preoperative and pathologic outcomes between TaTME and LaTME, and indicated the benefit of TaTME with low conversion. Extensive evaluations of well-designed, multicenter randomized controlled trials are required to come to unequivocal conclusions, but the results showed that TaTME is a potentially beneficial technique in some specific cases. This meta-analysis suggests that TaTME can be performed for rectal cancer patients as a ‘New Health Technology’ endorsed by NECA in South Korea.

Purpose: Under the South Korea’s unique health insurance structure, any new surgical technology must be evaluated first by the government in order to consider whether that particular technology can be applied to patients for further clinical trials as categorized as ‘New Health Technology,’ then potentially covered by the insurance sometime later. The aim of this meta-analysis was to assess the safety and efficacy of transanal total mesorectal excision (TaTME) for rectal cancer, activated by the National Evidence-based Healthcare Collaborating Agency (NECA) TaTME committee. Methods: We systematically searched Ovid-MEDLINE, Ovid-Embase, Cochrane, and Korean databases (from their inception until August 31, 2019) for studies published that compare TaTME with laparoscopic total mesorectal excision (LaTME). End-points included perioperative and pathological outcomes. Results: Sixteen cohort studies (7 for case-matched studies) were identified, comprising 1,923 patients (938 TaTMEs and 985 LaTMEs). Regarding perioperative outcomes, the conversion rate was significantly lower in TaTME (risk ratio, 0.19; 95% confidence interval, 0.11–0.34; P < 0.001); whereas other perioperative outcomes were similar to LaTME. There were no statistically significant differences in pathological results between the 2 procedures. Conclusion Our meta-analysis showed comparable results in preoperative and pathologic outcomes between TaTME and LaTME, and indicated the benefit of TaTME with low conversion. Extensive evaluations of well-designed, multicenter randomized controlled trials are required to come to unequivocal conclusions, but the results showed that TaTME is a potentially beneficial technique in some specific cases. This meta-analysis suggests that TaTME can be performed for rectal cancer patients as a ‘New Health Technology’ endorsed by NECA in South Korea.

BACKGROUND: The objectives of this study were to design polycaprolactone nanofibers with a radial pattern using a modified electrospinning method and to evaluate the effect of radial nanofiber deposition on mechanical and biological properties compared to non-patterned samples. METHODS: Radially patterned polycaprolactone nanofibers were prepared with a modified electrospinning method and compared with randomly deposited nanofibers. The surface morphology of samples was observed under scanning electron microscopy (SEM). The tensile properties of nanofibrous mats were measured using a tabletop uniaxial testing machine. Fluorescence-stained human bone marrow stem cells were placed along the perimeter of the radially patterned and randomly deposited. Their migration toward the center was observed on days 1, 4, and 7, and quantitatively measured using ImageJ software. RESULTS: Overall, there were no statistically significant differences in mechanical properties between the two types of polycaprolactone nanofibrous mats. SEM images of the obtained samples suggested that the directionality of the nanofibers was toward the central area, regardless of where the nanofibers were located throughout the entire sample. Florescence images showed stronger fluorescence inside the circle in radially aligned nanofibers, with significant differences on days 4 and 7, indicating that migration was quicker along radially aligned nanofibers than along randomly deposited nanofibers. CONCLUSIONS: In this study, we successfully used modified electrospinning to fabricate radially aligned nanofibers with similar mechanical properties to those of conventional randomly aligned nanofibers. In addition, we observed faster migration along radially aligned nanofibers than along randomly deposited nanofibers. Collectively, the radially aligned nanofibers may have the potential for tissue regeneration in combination with stem cells.
Bandages ; Bone Marrow ; Fluorescence ; Humans ; Methods ; Microscopy, Electron, Scanning ; Nanofibers ; Polymers ; Regeneration ; Stem Cells ; Wound Healing ; Wounds and Injuries

BACKGROUND: From May to July 2015, the Republic of Korea experienced the largest outbreak of Middle East respiratory syndrome (MERS) outside the Arabian Peninsula. A total of 186 patients, including 36 deaths, had been diagnosed with MERS-coronavirus (MERS-CoV) infection as of September 30th, 2015. MATERIALS AND METHODS: We obtained information of patients who were confirmed to have MERS-CoV infection. MERS-CoV infection was diagnosed using real-time reverse-transcriptase polymerase chain reaction assay. RESULTS: The median age of the patients was 55 years (range, 16 to 86). A total of 55.4% of the patients had one or more coexisting medical conditions. The most common symptom was fever (95.2%). At admission, leukopenia (42.6%), thrombocytopenia (46.6%), and elevation of aspartate aminotransferase (42.7%) were observed. Pneumonia was detected in 68.3% of patients at admission and developed in 80.8% during the disease course. Antiviral agents were used for 74.7% of patients. Mechanical ventilation, extracorporeal membrane oxygenation, and convalescent serum were employed for 24.5%, 7.1%, and 3.8% of patients, respectively. Older age, presence of coexisting medical conditions including diabetes or chronic lung disease, presence of dyspnea, hypotension, and leukocytosis at admission, and the use of mechanical ventilation were revealed to be independent predictors of death. CONCLUSION: The clinical features of MERS-CoV infection in the Republic of Korea were similar to those of previous outbreaks in the Middle East. However, the overall mortality rate (20.4%) was lower than that in previous reports. Enhanced surveillance and active management of patients during the outbreak may have resulted in improved outcomes.
Antiviral Agents ; Aspartate Aminotransferases ; Coronavirus Infections* ; Disease Outbreaks ; Dyspnea ; Extracorporeal Membrane Oxygenation ; Fever ; Humans ; Hypotension ; Leukocytosis ; Leukopenia ; Lung Diseases ; Middle East Respiratory Syndrome Coronavirus ; Middle East* ; Mortality ; Pneumonia ; Polymerase Chain Reaction ; Republic of Korea* ; Respiration, Artificial ; Thrombocytopenia

OBJECTIVES: There were previous studies which indicated that attitude toward suicide is able to influence the suicide outcome in both individual and group levels. In regard to the highest suicide rate in Korea, our study aims to explore the influence that attitude toward suicide has on suicide by comparing the national attitude towards suicide with a representative sample of the general population. METHODS: The target population was 20- to 59-year-old adults from South Korea, Japan, and the United States. The panel data were divided according to gender, age, and residential area of individuals, and an email with a hyperlink to our web survey was sent to the randomly selected participants in each stratum. To measure the perceptual differences about suicide in different cultures, this study adopted the Attitudes Toward Suicide questionnaire. RESULTS: A total of 2247 subjects in three countries participated in this study. According to results from factor analysis, there were different structure of factors and included items within factors in the three countries : five factors with nineteen items in South Korea, five factors with nineteen items in the United States, and five factors with twenty-five items in Japan. With regard to permissive attitude toward suicide, the mean value of permissiveness was not significantly different among countries, but permissiveness according to education level, gender, and marital status was different in each country. CONCLUSIONS: This study is the first nationwide comparative study about attitude toward suicide with a representative sample. Our findings suggest that permissive attitude toward suicide influence the suicide phenomenon in each country ; however, its impact is not a mean score of permissiveness, but the detailed difference by various demographics.
Adult ; Demography ; Education ; Electronic Mail ; Factor Analysis, Statistical ; Health Services Needs and Demand ; Humans ; Japan* ; Korea* ; Marital Status ; Middle Aged ; Permissiveness ; Suicide* ; United States*