• Korean Journal of Clinical Laboratory Science
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• v.54 no.2
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• pp.103-109
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• 2022

In December 2019, the coronavirus disease 2019 (COVID-19) caused by the virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in China and spread rapidly around the world, infecting millions of people. Cases of COVID-19 infection were observed to lead to viral pneumonia. Thirty-five patients admitted to the Gyeonggi Medical Center, South Korea, between November 2020 to January 2021, were found to have been infected with the influenza virus A and B, which cause symptoms similar to COVID-19. The records of these patients and those of COVID-19 patients who visited the hospital for medical examination were compared. The study patients included thirty patients with COVID-19 and/or influenza, five of those with influenza alone. A group of 121 patients without infection was used as control. Patients with COVID-19 and influenza had significantly higher lactate dehydrogenase levels than the patients with COVID-19 alone. The erythrocyte sedimentation rate (ESR) was higher in patients with COVID-19 alone than in other groups. Significant clinical outliers were observed in the COVID-19 and influenza infection group compared with the COVID-19 alone group. These results are expected to play an important role in the analysis of the hematological data of infected patients and the comparison of simultaneous and single infection data to determine clinical symptoms and other signs. These results may also assist in the development of vaccines and treatments for COVID-19.

• Korean Journal of Radiology
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• v.22 no.6
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• pp.994-1004
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• 2021

Objective: To extract pulmonary and cardiovascular metrics from chest CTs of patients with coronavirus disease 2019 (COVID-19) using a fully automated deep learning-based approach and assess their potential to predict patient management. Materials and Methods: All initial chest CTs of patients who tested positive for severe acute respiratory syndrome coronavirus 2 at our emergency department between March 25 and April 25, 2020, were identified (n = 120). Three patient management groups were defined: group 1 (outpatient), group 2 (general ward), and group 3 (intensive care unit [ICU]). Multiple pulmonary and cardiovascular metrics were extracted from the chest CT images using deep learning. Additionally, six laboratory findings indicating inflammation and cellular damage were considered. Differences in CT metrics, laboratory findings, and demographics between the patient management groups were assessed. The potential of these parameters to predict patients' needs for intensive care (yes/no) was analyzed using logistic regression and receiver operating characteristic curves. Internal and external validity were assessed using 109 independent chest CT scans. Results: While demographic parameters alone (sex and age) were not sufficient to predict ICU management status, both CT metrics alone (including both pulmonary and cardiovascular metrics; area under the curve [AUC] = 0.88; 95% confidence interval [CI] = 0.79-0.97) and laboratory findings alone (C-reactive protein, lactate dehydrogenase, white blood cell count, and albumin; AUC = 0.86; 95% CI = 0.77-0.94) were good classifiers. Excellent performance was achieved by a combination of demographic parameters, CT metrics, and laboratory findings (AUC = 0.91; 95% CI = 0.85-0.98). Application of a model that combined both pulmonary CT metrics and demographic parameters on a dataset from another hospital indicated its external validity (AUC = 0.77; 95% CI = 0.66-0.88). Conclusion: Chest CT of patients with COVID-19 contains valuable information that can be accessed using automated image analysis. These metrics are useful for the prediction of patient management.

• Pediatric Infection and Vaccine
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• v.30 no.2
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• pp.84-90
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• 2023

Purpose: Infants aged ≤90 days with fever are susceptible to severe infections. This study aimed to analyze the clinical features of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in this particular age group. Methods: Infants aged ≤90 days who were diagnosed with coronavirus disease 2019 (COVID-19) and hospitalized between March 1, 2020, and May 1, 2022 were included. Medical records of patients were retrospectively reviewed. Results: A total of 105 infants with COVID-19 were included; 27 (25.7%) neonates aged <28 days, and 48 (45.7%) and 30 (28.6%) infants aged 28-59 days and 60-90 days, respectively. Five (4.7%) patients remained asymptomatic and 68 (62.8%) were febrile, with a median fever duration of 2 days. The most common symptoms were respiratory including cough (66.6%), nasal stuffiness (51.4%), and rhinorrhea (40.9%). Blood cultures were performed in 10 infants but no organisms were detected. Cultures of bag-collected urine specimens from 8 infants were grown, resulting in positive growth for 2 without pyuria. Nine (8.6%) infants were treated with empirical antibiotics for a median duration of 2.3 days (range, 1-7 days). All 105 infants showed improvement without any complications, and there were no fatal cases. Conclusions: In this study, most infants aged ≤90 days with COVID-19 presented with mild symptoms and none of those evaluated had documented bacterial co-infection. The favorable prognosis among young infants with SARS-CoV-2 may aid clinicians in tailoring their approach to evaluation and management during outbreaks.

• IMMUNE NETWORK
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• v.21 no.4
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• pp.29.1-29.9
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• 2021

There are limited data directly comparing humoral and T cell responses to the ChAdOx1 nCoV-19 and BNT162b2 vaccines. We compared Ab and T cell responses after first doses of ChAdOx1 nCoV-19 vs. BNT162b2 vaccines. We enrolled healthcare workers who received ChAdOx1 nCoV-19 or BNT162b2 vaccine in Seoul, Korea. Anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S1 protein-specific IgG Abs (S1-IgG), neutralizing Abs (NT Abs), and SARS-CoV-2-specific T cell response were evaluated before vaccination and at 1-wk intervals for 3 wks after vaccination. A total of 76 persons, comprising 40 injected with the ChAdOx1 vaccine and 36 injected with the BNT162b2 vaccine, participated in this study. At 3 wks after vaccination, the mean levels (±SD) of S1-IgG and NT Abs in the BNT162b2 participants were significantly higher than in the ChAdOx1 participants (S1-IgG, 14.03±7.20 vs. 6.28±8.87, p<0.0001; NT Ab, 183.1±155.6 vs. 116.6±116.2, p=0.035), respectively. However, the mean values of the T cell responses in the 2 groups were comparable after 2 wks. The humoral immune response after the 1st dose of BNT162b2 developed faster and was stronger than after the 1st dose of ChAdOx1. However, the T cell responses to BNT162b2 and ChAdOx1 were similar.

• IMMUNE NETWORK
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• v.23 no.4
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• pp.33.1-33.13
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• 2023

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been acknowledged as an effective mean of preventing infection and hospitalization. However, the emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs) has led to substantial increase in infections among children and adolescents. Vaccine-induced immunity and longevity have not been well defined in this population. Therefore, we aimed to analyze humoral and cellular immune responses against ancestral and SARS-CoV-2 variants after two shots of the BNT162b2 vaccine in healthy adolescents. Although vaccination induced a robust increase of spike-specific binding Abs and neutralizing Abs against the ancestral and SARS-CoV-2 variants, the neutralizing activity against the Omicron variant was significantly low. On the contrary, vaccine-induced memory CD4⁺ T cells exhibited substantial responses against both ancestral and Omicron spike proteins. Notably, CD4⁺ T cell responses against both ancestral and Omicron strains were preserved at 3 months after two shots of the BNT162b2 vaccine without waning. Polyfunctionality of vaccine-induced memory T cells was also preserved in response to Omicron spike protein. The present findings characterize the protective immunity of vaccination for adolescents in the era of continuous emergence of variants/subvariants.

• Information Systems Review
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• v.24 no.1
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• pp.21-37
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• 2022

Drug repositioning, one of the methods of developing new drugs, is a useful way to discover new indications by allowing drugs that have already been approved for use in people to be used for other purposes. Recently, with the development of machine learning technology, the case of analyzing vast amounts of biological information and using it to develop new drugs is increasing. The use of machine learning technology to drug repositioning will help quickly find effective treatments. Currently, the world is having a difficult time due to a new disease caused by coronavirus (COVID-19), a severe acute respiratory syndrome. Drug repositioning that repurposes drugsthat have already been clinically approved could be an alternative to therapeutics to treat COVID-19 patients. This study intends to examine research trends in the field of drug repositioning using machine learning techniques. In Pub Med, a total of 4,821 papers were collected with the keyword 'Drug Repositioning'using the web scraping technique. After data preprocessing, frequency analysis, LDA-based topic modeling, random forest classification analysis, and prediction performance evaluation were performed on 4,419 papers. Associated words were analyzed based on the Word2vec model, and after reducing the PCA dimension, K-Means clustered to generate labels, and then the structured organization of the literature was visualized using the t-SNE algorithm. Hierarchical clustering was applied to the LDA results and visualized as a heat map. This study identified the research topics related to drug repositioning, and presented a method to derive and visualize meaningful topics from a large amount of literature using a machine learning algorithm. It is expected that it will help to be used as basic data for establishing research or development strategies in the field of drug repositioning in the future.

• Journal of Cardiovascular Imaging
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• v.31 no.1
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• pp.18-23
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• 2023

BACKGROUND: Three-dimensional (3D) transesophageal echocardiogram (TEE) is the gold standard for the diagnosis of degenerative mitral regurgitation (dMR) and preoperative planning for transcatheter mitral valve repair (TMVr). TEE is an invasive modality requiring anesthesia and esophageal intubation. The severe acute respiratory syndrome coronavirus 2 pandemic has limited the number of elective invasive procedures. Multi-detector computed tomographic angiography (MDCT) provides high-resolution images and 3D reconstructions to assess complex mitral anatomy. We hypothesized that MDCT would reveal similar information to TEE relevant to TMVr, thus deferring the need for a preoperative TEE in certain situations like during a pandemic. METHODS: We retrospectively analyzed data on patients who underwent or were evaluated for TMVr for dMR with preoperative MDCT and TEE between 2017 and 2019. Two TEE and 2 MDCT readers, blinded to patient outcome, analyzed: leaflet pathology (flail, degenerative, mixed), leaflet location, mitral valve area (MVA), flail width/gap, anterior-posterior (AP) and commissural diameters, posterior leaflet length, leaflet thickness, presence of mitral valve cleft and degree of mitral annular calcification (MAC). RESULTS: A total of 22 (out of 87) patients had preoperative MDCT. MDCT correctly identified the leaflet pathology in 77% (17/22), flail leaflet in 91% (10/11), MAC degree in 91% (10/11) and the dysfunctional leaflet location in 95% (21/22) of patients. There were no differences in the measurements for MVA, flail width, commissural or AP diameter, posterior leaflet length, and leaflet thickness. MDCT overestimated the measurements of flail gap. CONCLUSIONS: For preoperative TMVr planning, MDCT provided similar measurements to TEE in our study.

• KSBB Journal
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• v.22 no.6
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• pp.371-377
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• 2007

Polyhydroxyalkanoates (PHAs) are a family of microbial polyesters that can be produced by fermentation from renewable resources. PHAs can be used as completely biodegradable plastics or elastomers. In this paper, novel applications of PHAs in biosensor are described. A general platform technology was developed by using the substrate binding domain (SBD) of PHA depolymerase as a fusion partner to immobilize proteins of interest on PHA surface. It could be shown that the proteins fused to the SBD of PHA depolymerase could be specifically immobilized onto PHA film, PHA microbead, and microcontact printed PHA surface. We review the results obtained for monitoring the specific interaction between the SBO and PHA by using enhanced green fluorescent protein, red fluorescent protein, single chain antibody against hepatitis B virus preS2 surface protein and severe acute respiratory syndrome coronavirus surface antigen as model proteins. Thus, this system can be efficiently used for studying protein-protein and possibly protein-biomolecule interactions for various biotechnological applications.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.3
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• pp.284-295
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• 2020

In December 2019, the first coronavirus disease- 2019 (COVID-19) patient was reported in Wuhan, Hubei Province, China. Since then, the number of patients who suffered severe acute respiratory syndrome caused by the novel Coronavirus (SARS-CoV-2 or 2019-nCoV) has increased dramatically in Korea. This new variant virus induces pulmonary diseases, including cough, sore throat, rhinorrhea, dyspnea, and pneumonia. Because SARS-CoV-2 is an RNA virus, real-time reverse-transcriptase PCR has been used widely to diagnose COVID-19. As the Korea Centers for Disease Prevention and Control (KCDC) and Ministry of Food & Drug Safety (MFDS) approved emergency use authorization, clinical specimens collected from COVID-19 patients and even healthy people have been clinically diagnosed by laboratory medicine. Based on a literature search, this paper reviews the epidemiology, symptoms, molecular diagnostics approved by KCDC, a current diagnosis of COVID-19 in the laboratories, the difference between molecular and serological diagnosis, and guidelines for clinical specimens. In addition, the Korean guidelines of biosafety for clinical laboratory scientists are evaluated to prevent healthcare-associated infection. The author's experience and lessons as clinical laboratory scientists will provide valuable insights to protect the domestic and international health community in this COVID-19 pandemic around the world.

• IMMUNE NETWORK
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• v.24 no.2
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• pp.7.1-7.19
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• 2024

Viral load and the duration of viral shedding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are important determinants of the transmission of coronavirus disease 2019. In this study, we examined the effects of viral doses on the lung and spleen of K18-hACE2 transgenic mice by temporal histological and transcriptional analyses. Approximately, 1×10⁵ plaque-forming units (PFU) of SARS-CoV-2 induced strong host responses in the lungs from 2 days post inoculation (dpi) which did not recover until the mice died, whereas responses to the virus were obvious at 5 days, recovering to the basal state by 14 dpi at 1×10² PFU. Further, flow cytometry showed that number of CD8+ T cells continuously increased in 1×10² PFU-virus-infected lungs from 2 dpi, but not in 1×10⁵ PFU-virus-infected lungs. In spleens, responses to the virus were prominent from 2 dpi, and number of B cells was significantly decreased at 1×10⁵ PFU; however, 1×1² PFU of virus induced very weak responses from 2 dpi which recovered by 10 dpi. Although the defense responses returned to normal and the mice survived, lung histology showed evidence of fibrosis, suggesting sequelae of SARS-CoV-2 infection. Our findings indicate that specific effectors of the immune response in the lung and spleen were either increased or depleted in response to doses of SARS-CoV-2. This study demonstrated that the response of local and systemic immune effectors to a viral infection varies with viral dose, which either exacerbates the severity of the infection or accelerates its elimination.