• BMB Reports
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• v.37 no.2
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• pp.167-176
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• 2004

Although efficient antiviral lamivudine is used for HBV-infected patients, a prolonged treatment with nucleoside analogs often results in lamivudine-resistant variants. In this study, we evaluated the fidelity of the lamivudine-resistant variants. The FLAG-tagged wild-type (FPolE) and Met550 variants (FPolE/M550A, M550V, and M550I) of HBV DNA polymerases were expressed in insect cells then purified. Like many other reverse transcriptases, no $3'{\rightarrow}5'$ exonuclease activity was detected in the HBV DNA polymerase. Since there is no proofreading activity, then the use of the site-specific nucleotide misincorporation method is beneficial. From the $f_{ins}$ value analysis, it is evident that M550I and M550V exhibit higher fidelity values than the wild-type HBV DNA polymerase, while M550A exhibits similar fidelity values. It is therefore suggested that lamivudine resistance comes from the stringency to dNTP binding and the discrimination of dCTP and lamivudine in M550V and M550I.

• Tuberculosis and Respiratory Diseases
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• v.85 no.4
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• pp.320-331
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• 2022

Coronavirus disease 2019 (COVID-19) has become a major health burden worldwide, with over 450 million confirmed cases and 6 million deaths. Although the acute phase of COVID-19 management has been established, there is still a long way to go to evaluate the long-term clinical course or manage complications due to the relatively short outbreak of the virus. Pulmonary fibrosis is one of the most common respiratory complications associated with COVID-19. Scarring throughout the lungs after viral or bacterial pulmonary infection have been commonly observed, but the prevalence of post-COVID-19 pulmonary fibrosis is rapidly increasing. However, there is limited information available about post-COVID-19 pulmonary fibrosis, and there is also a lack of consensus on what condition should be defined as post-COVID-19 pulmonary fibrosis. During a relatively short follow-up period of approximately 1 year, lesions considered related to pulmonary fibrosis often showed gradual improvement; therefore, it is questionable at what time point fibrosis should be evaluated. In this review, we investigated the epidemiology, risk factors, pathogenesis, and management of post-COVID-19 pulmonary fibrosis.

• Tuberculosis and Respiratory Diseases
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• v.67 no.2
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• pp.135-139
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• 2009

Human metapneumovirus (hMPV) is a recently recognized human respiratory pathogen, which is known to be associated with upper and lower respiratory tract infections mainly in children, immunocompromised patients, and the elderly. The clinical manifestations of hMPV infections are similar to those of the human respiratory syncytial virus infection, which range from mild upper respiratory tract infection to severe bronchiolitis and pneumonia. Recently, hMPV has come to be thought of as the cause a similar spectrum of disease in adults as that seen in children; however, most of the reports of hMPV infections have focused on infection in children. We report a case of severe hMPV pneumonia requiring mechanical ventilation in an immunocompetent adult in Korea.

• YAKHAK HOEJI
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• v.52 no.1
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• pp.73-78
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• 2008

Immune system can protect host attacking from a variety of microorganism and virus through innate and adaptive immunities. The innate immune system can be activated by recognition of conserved carbohydrates on the cell surface of pathogen resulting in protection, immunity regulation and inflammation. Immunostimulating and anti-tumor ${\beta}$-glucan, major cell wall component of many fungi, could be recognized as pathogen associated molecular pattern (PAMP) by C-type lectin such as pathogen recognition receptor (PRR) of host innate immunity cells. In spite of many studies of basidiomycetes ${\beta}$-glucan on immunostimulation, little is known about the precise mechanism as molecular-level. Among C-type lectins, dectin-1 was cloned and reported as a ${\beta}$-glucan receptor. In this report, we demonstrated induction of cytokine gene transcription by Ganoderma lucidum ${\beta}$-glucan in the absence or presence of lipopolysaccharide (LPS) by RT-PCR analysis. The expression of murine dectin-1 (MD-1) on RAW264.7 macrophage by RT-PCR showing both the full length, 757 bp $(MD-1{\alpha})$ and alternative spliced form, 620 bp $(MD-1{\beta})$. Both $MD-1{\alpha}$ and $MD-1{\beta}$ mRNAs were induced by ${\beta $-glucan both in the absence and presence of LPS. To explore expression of inflammatory cytokines by ${\beta}$-glucan, RAW264.7 cells were treated with ${\beta}$-glucan for 12 hours. As a result, the expressions of IL-1 IL-6, IL-l0 and $TNF-{\alpha}$ were increased by ${\beta}$-glucan treatment in a dose-dependent fashion. From these results, ${\beta}$-glucan induced transcriptions of dectin-1 and immune activating cytokine genes, indicating induction of immune allertness by expressing dectin-1 and secreting inflammatory cytokines.

• Journal of Preventive Medicine and Public Health
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• v.45 no.3
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• pp.156-163
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• 2012

Objectives: It is necessary to examine groups carrying out sexually risky behavior because the prevalence of sexually transmitted diseases (STDs) is high among them. In this study, the prevalence of STDs among homosexuals and sexbuying men in South Korea was investigated, along with their sexual risk factors. Methods: Men who have sex with men (MSMs, n=108) were recruited in Seoul and Busan by applying the time location sampling method, while sex-buying men (n=118) were recruited from a john school in Gyeonggi province, the suburbs of Seoul. Dependent variables included past or present infection with syphilis, Chlamydia, gonorrhea, and human immunodeficiency virus. Independent variables included health behavior, social support, sexual behavior, and safe sex. Results: It was found that when the MSMs were non-drunk while having sexual intercourse (odds ratio [OR], 0.132), they showed a higher STD infection rate when they had a higher number of anal sex partners (OR, 5.872), rarely used condoms (OR, 1.980), had lower self-efficacy (OR, 0.229), and were more anxious about becoming infected with an STD (OR, 3.723). However, the men who paid for sex showed high STD infections when they had more sex partners (OR, 2.286) and lower education levels (OR, 3.028). Conclusions: STD infections among the two groups were high when they were engaged with many sex partners and not having protected sex. In other words, there was a gap in risky sex behavior within such groups, which was significantly related to the possibility of developing an STD. Therefore, the preventive intervention against STDs for these groups needs to be expanded to include management of sex behaviors.

• Environmental Engineering Research
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• v.20 no.2
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• pp.133-140
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• 2015

The aim of this study was to investigate the bacteriophage removal in various clay minerals and clay-amended soils. Batch experiments in kaolinite, montmorillonite, and bentonite showed that kaolinite was far more effective at the MS2 removal than montmorillonite and bentonite. In kaolinite, the log removal increased from 0.046 to 2.18, with an increase in the adsorbent dose from 0.3 to $50g\;L^{-1}$, whereas the log removals in montmorillonite and bentonite increased from 0.007 to 0.40 and from 0.012 to 0.59, respectively. The MS2 removal in kaolinite-amended silt loam soils was examined at three different soil-to-solution (STS) ratios. Results indicated that the log removal of MS2 increased with an increase in the kaolinite content and the STS ratio. At the STS ratio of 1:10, the log removal of MS2 increased from 2.33 to 2.80 with an increase in the kaolinite content from 0% to 10% in kaolinite-amended soils. The log removals of MS2 at the STS ratios of 1:2 and 1:1 increased from 2.84 to 3.47 and from 3.46 to 4.76, respectively, with an increase in the kaolinite content from 0% to 10%. Results also indicated that the log removals of PhiX174 and $Q{\beta}$ in kaolinite-amended soils were similar to each other, but they were far lower than those of MS2 at all the kaolinite contents. The log removal of PhiX174 increased from 0.16 to 0.32, whereas the log removal of $Q{\beta}$ changed from 0.17 to 0.22 with an increase in the kaolinite content from 0% to 10%.

• Korean Journal of Veterinary Pathology
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• v.2 no.2
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• pp.139-145
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• 1998

A total of 5 animals including 3 raccoons, 1 badger, and 1 fennec fox kept in outdoor exhibits at the Everland Zoological Gardens showed depression, anorexia, dyspnea, serous oculonasal discharge, diarrhea, and convulsions. All the affected animals died within 10 days after the onset of clinical signs. This outbreak lasted about 4 months. On necropsy, major gross lesions were confined to the lungs. Red to grey sublobular to lobular consolidations with various sized tan to reddish spots were observed in the lungs. Histopathologically, the pulmonary lesions were characterized by acute to subacute bronchointerstitial pneumonia with secondary bacterial or adenoviral infections. Intracytoplasmic eosinophilic inclusion bodies compatible with canine distemper virus (CDV) were found in the lung, urinary bladder, kidney, intrahepatic bile duct, stomach, small and large intestines. Multifocal areas of severe demyelination and accumulation of gitter cells or nonsuppurative inflammation were seen in the brains of 2 raccoons. CDV -specific antigens were demonstrated in the lung sections on immunofluorescent assay. The present report describes an outbreak of CDV infection in a zoo and indicates the range of susceptible zoo animal species.

• Toxicological Research
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• v.33 no.4
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• pp.343-350
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• 2017

Lamivudine belongs to the set of antiviral agents effective against hepatitis B virus infection. Given case reports on liver injuries after certain antiviral agent treatments, this study examined the effects of lamivudine on alanine aminotransferase (ALT) and total bilirubin (TB) using a medical system database. A total of 1,321 patients taking lamivudine alone or with others were evaluated using laboratory hits in an electronic medical system at Seoul National University Hospital from 2005 through 2011. The patients were grouped according to prior ALT results: G#1, ALT < 40 IU/L; G#2, 40 IU/L ${\leq}$ ALT < 120 IU/L; G#3, 120 IU/L ${\leq}$ ALT < 240 IU/L; and G#4, ALT ${\geq}$ 240 IU/L. In G#1 and G#2 patients, lamivudine or adefovir treatment decreased ALT and TB compared to prior values. In G#3 and G#4 patients with three times the upper limit of normal (ULN) ${\leq}$ ALT < 15 times the ULN, both ALT and TB were decreased after treatment with lamivudine alone, or adefovir following lamivudine therapy, indicating that lamivudine therapy ameliorated liver functions. However, in G#4 patients who experienced severely advanced hepatitis (ALT ${\geq}$ 15 times the ULN, or ${\geq}$ 600 IU/L), lamivudine augmented TBmax ($6.3{\rightarrow}13.3mg/dL$) despite a slight improvement in ALT ($839{\rightarrow}783IU/L$), indicative of exacerbation of bilirubinemia. Patients who used adefovir after lamivudine also showed a high incidence of hyperbilirubinemia when they experienced severely advanced hepatitis. Treatment with adefovir alone did not show the effect. In conclusion, lamivudine may increase the risk of hyperbilirubinemia in patients with severely advanced hepatitis, implying that caution should be exercised when using lamivudine therapy in certain patient populations.

• Pediatric Infection and Vaccine
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• v.29 no.1
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• pp.54-60
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• 2022

Salmonella meningitis is rare yet poses causes significant neurological morbidity in children. Infants, especially those under 3 months of age, and those with immunocompromised states, such as malignancy, malaria, and human immunodeficiency virus infection, are at increased risk for developing Salmonella meningitis. Herein, we describe a case of Salmonella meningitis in a previous healthy 8-year-old girl who presented with high fever, vomiting, and altered mental status. Group D Salmonella species were isolated in cerebrospinal fluid culture, and no abnormal findings were noted in brain magnetic resonance imaging. Immunoglobulin levels and lymphocyte subset counts were within the normal ranges, and no genetic mutation responsible for primary immunodeficiency disease was detected by next-generation sequencing. The patient's condition improved rapidly with third-generation cephalosporin, and no complications or sequalae developed. Nontyphoidal Salmonella can cause meningitis in immunocompetent children and can be successfully treated with early administration of antibiotics.

• Journal of Periodontal and Implant Science
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• v.39 no.sup2
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• pp.279-286
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• 2009

Purpose: Gene therapy (ex vivo) has recently been used as a means of delivering bone morphogenetic proteins (BMPs) to sites of tissue regeneration. In the present study, we investigated the effect of co-transduction of adenoviruses expressing BMP-2 and BMP-7 on osteogenesisof C2C12 cells in vitro. Methods: A replication-defective human adenovirus 5 (Ad5) containing a cDNA for BMPs in the E1 region of the virus (Ad5BMP-2 and Ad5BMP-7) was constructed by in vivo homologous recombination. Functional activity of Ad5BMP-2 and Ad5BMP-7 were evaluated in mouse stromal cells (W20-17cells). C2C12 cells are transduced with various MOI (multiplicity of infection) of Ad5BMP-2 and Ad5BMP-7 to assess most effective and stable titer. Based on this result, C2C12 cells were transduced with Ad5BMP-2 and Ad5BMP-7 alone or by combination. BMPs expression, alkaline phosphatase (ALPase) activity, cell proliferation, and mineralization were assessed. Results: Ad5BMP-2 and Ad5BMP-7 are successfully transduced to W20-17 cells, and secreted BMPs stimulated cell differentiation. Also, C2C12 cells transduced with Ad5BMPs showed expression of BMPs and increased ALPaseactivity. In all groups, cell proliferation was observed over times. At 7days, cells co-transduced with Ad5BMP-2 and Ad5BMP-7 showed lower proliferation than the others. C2C12 cells co-transduced with Ad5BMP-2 and Ad5BMP-7 had greater ALPaseactivity than that would be predicted if effect of individual Ad5BMPs were additive. Little mineralized nodule formation was detected in cells transduced with individual Ad5BMPs. In contrast, Ad5BMP-2 and Ad5BMP-7 combination stimulated mineralization after culturing for 10 days in mineralizing medium. Conclusions: Present study demonstrated that adenoviruses expressing BMPs gene successfully produced BMPs protein and these BMPs stimulated cells to be differentiated into osteoblastic cells. In addition, the osteogenic activity of Ad5BMPs can be synergistically increased by co-transduction of cells with Ad5BMP-2 and Ad5BMP-7.