• Research in Plant Disease
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• v.16 no.1
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• pp.21-26
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• 2010

Viral diseases, especially Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV) have been most serious in barley fields. In this study, we investigated the effect of different level of resistance to viral diseases on the plant growth and yield in malting barley. In diagnosis of virus infection, BaYMV and BaMMV were detected in 'Doosan 29' (susceptible), however, 'Jinyangbori' (moderate susceptible) and 'Hopumbori' (moderate) was infected by only BaYMV. Plant height was restrained about 8~29% in overwintered plant regeneration stage depending on the resistant of each cultivar. The culm length damaged also to 9~12% by BaYMV infection. The tiller numbers reduced to 10~14% in overwintering season, however, the head numbers in harvest season more decreased to 26~33%. Heading date was delayed to 3~3 days by the infection. In examination of yield components, 1,000 kernel weight and $\ell$ weight reduced according to culrivar's resistant degrees to 4.0~6.4% and 1.0~4.2%, respectively. The yield of abortive grain was doubled in BaYMV infection comparing to non-infested field. Three varieties tested in the non-infected field over two years were not significantly different for yield potential with ranges of 509kg~632kg/10a. However, significant yield reduction was observed in 'Saessalbori' and 'Baegdong' with ranges of 77~177kg/10a as compared to 'Hopumbori' (467 kg/10a) when tested in the virus-infected field. Yield potentials of these cultivars reduced by 26~43%, respectively, in the virus-infected field as compared to those in the non-infected field.

• Pediatric Infection and Vaccine
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• v.23 no.3
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• pp.165-171
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• 2016

Purpose: Human parechovirus (HPeV) is an increasingly recognized pathogenic cause of central nervous system (CNS) infection in neonates. However, HPeV infections have not been studied in older children. This study determined the prevalence and clinical features of HPeV CNS infection in children in Korea. Methods: Reverse transcription polymerase chain reaction assays were performed using HPeV-specific, 5' untranslated, region-targeted primers to detect HPeV in cerebrospinal fluid (CSF) samples from children presenting with fever or neurologic symptoms from January 1, 2013, to July 31, 2014. HPeV genotyping was performed by sequencing the viral protein 3/1 region. Clinical and laboratory data were retrospectively abstracted from medical records and compared with those of enterovirus (EV)-positive patients from the same period. Results: Of 102 CSF samples, six (5.9%) were positive for HPeV; two of 21 EV-positive samples were co-infected with HPeV. All samples were genotype HPeV3. Two HPeV-positive patients were <3 months of age and four others were over 1 year old. While HPeV-positive infants under 1 year of age presented with sepsis-like illness without definite neurologic abnormalities, HPeV-positive children over 1 year of age presented with fever and neurologic symptoms such as seizures, loss of consciousness, and gait disturbance. The CSF findings of HPeV-positive patients were mostly within the normal range, whereas most (73.7%) EV-positive patients had pleocytosis. Conclusions: Although HPeV is typically associated with disease in young infants, the results of this study suggest that HPeV is an emerging pathogen of CNS infection with neurologic symptoms in older childhood.

• Clinical and Experimental Pediatrics
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• v.53 no.3
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• pp.373-379
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• 2010

Purpose : This study was performed to investigate the epidemiologic and clinical features of 13 respiratory viruses in children with acute lower respiratory tract infections (ALRIs). Methods : Nasopharyngeal aspirates were prospectively obtained from 325 children aged 15 years or less from May 2008 to April 2009 and were tested for the presence of 13 respiratory viruses by multiplex real-time-polymerase chain reaction (RT-PCR). Results : Viruses were identified in 270 children (83.1%). Co-infections with ${\geq}2$ viruses were observed in 71 patients (26.3 %). Respiratory syncytial virus (RSV) was the most common virus detected (33.2%), followed by human rhinovirus (hRV) (19.1%), influenza virus (Flu A) (16.9%), human metapneumovirus (hMPV) (15.4%), parainfluenza viruses (PIVs) (8.3%), human bocavirus (hBoV) (8.0%), adenovirus (ADV) (5.8%), and human coronavirus (hCoV) (2.2%). Clinical diagnoses of viral ALRIs were bronchiolitis (37.5%), pneumonia (34.5%), asthma exacerbation (20.9%), and croup (7.1%). Clinical diagnoses of viral bronchiolitis and pneumonia were frequently demonstrated in patients who tested positive for RSV, hRV, hMPV, or Flu A. Flu A and hRV were most commonly identified in children older than 3 years and were the 2 leading causes of asthma exacerbation. hRV C was detected in 14 (4.3%) children, who were significantly older than those infected with hRV A ($mean{\pm}SD$, $4.1{\pm}3.5$ years vs. $1.7{\pm}2.3$ years; P =0.009). hBoV was usually detected in young children ($2.3{\pm}3.4$ years) with bronchiolitis and pneumonia. Conclusion : This study described the features of ALRI associated with 13 respiratory viruses in Korean children. Additional investigations are required to define the roles of newly identified viruses in children with ALRIs.

• Research in Plant Disease
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• v.12 no.2
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• pp.139-143
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• 2006

Virion captured reverse transcription polymerase chain reaction (VC/RT-PCR) could detect plant virus quickly and accurately. In the VC/RT-PCR, no antibody is needed unlike immuno-captured RT-PCR (IC/RT-PCR) which had been improved method of RT-PCR for plant viruses, and virus nucleic acids can be obtained easily within 30minutes by property of polypropylene PCR tube which is hold and immobilized viral particles on its surface. For the virion capture of Tomato spotted wilt virus (TSWV), the extraction buffer was tested. The optimum macerating buffer for TSWV was 0.01M potassium phosphate buffer, pH 7.0, containing 0.5% sodium sulfite. The viral crude sap was incubated for 30 min at $4^{\circ}C$. The virions in the PCR tubes were washed two times with 0.01M PBS containing 0.05% Tween-20. The washed virions were treated at $95^{\circ}C$ immediately for 1 min containing RNase free water and chilled quickly in the ice. Disclosed virions' RNAs by heat treatment were used for RT-PCR. Dilution end point of $10^{-5}$ from plant's crude sap infected with TSWV showed relatively higher detection sensitivity for VC/RT-PCR. During multiple detection using two or more primers, interference was arisen by interactions between primer-primer and plant species. The result of multiplex RT-PCR was influenced by combinations of primers and the kind of plant, and the optimum extraction buffer for the multiplex detection by VC/RT-PCR should be developed.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.210-218
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• 2015

Melon leaves showing yellowing symptoms were analyzed using electron microscopy and RT-PCR for major cucurbit-infecting-viruses (CMV, MNSV, CGMMV, SqMV, WMV, KGMMV, PRSV and ZYMV) reported in Korea, but these viruses were not detected. As the result of further analysis by next-generation sequencing (NGS), the virus was identified as Cucurbit aphid-borne yellows virus (CABYV), and then confirmed by RT-PCR using CABYV-specific primers. When photosynthetic capacity was measured based on chlorophyll fluorescence yield (ChlFY), the leaves of the diseased plants showed $4.09{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, which was one-third of the readings observed for unaffected normal plants ($12.36{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). The root functions of plants affected by leaf yellowing symptoms (LYS) was $0.28mg{\cdot}g^{-1}$, about half that measured for the normal unaffected plants ($0.48mg{\cdot}g^{-1}$). Cytological observations revealed that there were no morphological differences in the palisade parenchyma and mesophyll spongy cells of the leaves between the diseased and the normal plants. However, the same leaf cells of the affected plants contained more starch granules compared to those of the normal, unaffected plants. We conclude that the LYS of muskmelon is not merely a physiological disorder but a viral disease caused by CABYV and spread by aphids.

• Research in Plant Disease
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• v.16 no.3
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• pp.238-246
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• 2010

In 2006 fall, a preliminary survey of viruses in two important medicinal plants, Cynanchum wilfordii and C. auriculatum, was conducted on the experimental fields at the Agricultural Research and Extension Services of Chungbuk province in Korea. On each experimental fields, percentage of virus infection was ranged from 20 to 80%, and especially an average of disease incidence propagated by roots was twice higher than that by seeds. The various symptoms were observed in Cynanchum spp. plants, such as mosaic, mottle, necrosis, yellowing, chlorotic spot and malformation etc. In electron microscopic examination of crude sap extracts, filamentous rod particles with 390-730 nm were observed in most samples. The virus particles were purified from the leaves of C. wilfordii with typical mosaic symptom, and the viral RNA was extracted from this sample containing 430-845 nm long filamentous rod. To identify the viruses, reverse transcription followed by PCR with random primers was carried out. The putative sequences of P3 and coat protein of potyvirus were obtained. From a BLAST of the two sequences, they showed 26-38% and 62-72% identities to potyviruses, respectively. In SDS-PAGE analysis, the subunit of coat protein was approximately 30.3 kDa, close to the coat protein of potyvirus. In bioassay with 21 species in 7 families, Chenopodium quinoa showed local lesion on inoculated leave and chlorotic spot on upper leave, but the others were not infected. RT-PCR detection using specific primer of C. wilfordii and C. auriculatum samples, all of 24 samples with virus symptom was positive, and five out of seven samples without virus symptom were also positive. On the basis of these data, the virus could be considered as a new member of potyvirus. We suggested that the name of the virus was Keunjorong mosaic virus (KjMV) after the common Korean name of C. wilfordii.

• Pediatric Infection and Vaccine
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• v.18 no.1
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• pp.40-47
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• 2011

Purpose : Norovirus infection, a common cause of community-acquired gastroenteritis, can also lead to severe illness in immunocompromised patients. We investigated clinical manifestations of norovirus infection in pediatric cancer patients. Methods : Stool specimens were collected from pediatric patients with gastrointestinal symptoms between November 2008 and September 2009 at Samsung Medical Center, Seoul, Korea. Norovirus infection was identified by reverse-transcription polymerase chain reaction (RT-PCR). A retrospective chart review was performed in pediatric cancer patients who were diagnosed with norovirus infection. Results : Ten patients were diagnosed with norovirus infection by RT-PCR in stool samples. The median age was 0.83 years (range 0.25-5.5 years) and the male to female ratio was 1.5:1 (6 males and 4 females). Underlying diseases were hematologic malignancies (4/10, 40%), neuroblastoma (4/10, 40%), and brain tumors (2/10, 20%). Three patients were infected before hematopoietic cell transplantation (HCT) and four patients after HCT. All patients had diarrhea (10/10, 100%), with a median frequency of diarrhea of 8.5 times/day (range 4-22 times/day). Median virus shedding duration was 72.5 days (range 19-299 days). Four patients with pneumatosis intestinalis were conservatively treated with bowel rest and total parenteral nutrition. One patient with severe diarrhea and bloody stool had concomitant chronic gut graft-versus-host disease (GVHD). Norovirus infection-related mortality was not observed. Conclusion : Norovirus infection can cause significant clinical manifestations with prolonged viral shedding in immunocompromised patients. Norovirus should be considered in pediatric cancer patients with severe gastrointestinal symptoms.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7825-7829
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• 2015

Background: Egypt has the highest prevalence of HCV infection in the world (~14.7%). Around 10-15% of HCV-infected persons will advance to cirrhosis within the first 20 years. The incidence of HCC is expected to grow in the next two decades, largely due to HCV related cirrhosis, and detection of HCC at an early stage is critical for a favorable clinical outcome. No simple reliable non-invasive marker has been available till now. B2M, a non-glycosylated polypeptide composed of 99 amino acids, is one of the components of HLA class I molecules on the surfaces of all nucleated cells. It has been reported that the level of serum B2M is elevated in patients with chronic hepatitis C and HCV-related HCC when compared to HCV-negative patients or healthy donors. Determining the clinical utility of serum B2M as a marker for disease progression in Egyptian patients with HCV related chronic hepatitis, cirrhosis and hepatocellular carcinoma was the aim of the present study. Materials and Methods: In this analytical cross sectional study 92 participants were included in 4 equal groups: Group (1) non cirrhotic chronic HCV; Group (2) HCV related liver cirrhosis; Group (3) HCC on top of HCV,; and Group (4) healthy controls. History taking, clinical examination, routine labs and abdominal ultrasound were conducted for all patients, PCR and Metavir scores for group (1) patients, and triphasic CT abdomen and AFP for Group (3) patients. B2M levels were measured in serum with a fully-automated IMX system. Results: The mean serum B2M level of Group (1) was $4.25{\pm}1.48{\mu}g/ml$., Group (2) was $7.48{\pm}3.04$, Group (3) was $6.62{\pm}2.49$ and Group (4) was $1.62{\pm}0.63$. Serum B2M levels were significantly higher in diseased than control group (p<0.01) being significantly higher in cirrhosis ($7.48{\pm}3.04$) and HCC groups ($6.62{\pm}2.49$) than the HCV group ($4.25{\pm}1.48$) (p<0.01). There was a significant correlation between B2M Level and ALK, total and direct bilirubin and INR (p<0.05), and a significant inverse correlation between B2M level and albumin, total proteins, HB andWBCS values (p<0.05). There was no significant correlation between B2M level and viral load or Metavir score, largest tumour size or AFP (p>0.05). The best B2M cut-off for HCV diagnosis was 2.6 with a sensitivity of 100%, a specificity of 92%, a positive predictive value (PPV) of 97% and a negative predictive value (NPV) of 100%. The best B2M cut-off for HCC diagnosis was 4.55 which yielded sensitivity, specificity, positive predictive value, negative predictive values of 74%, 62%, 39.5, 87.8% respectively (p-value <0.01) while best cut-off for cirrhosis was 4.9, with sensitivity 74 % and specificity 74%.The sensitivity for HCC diagnosis increased upon B2M and AFP combined estimation to 91%, specificity to 79%, NPV to 95% and accuracy to 83%. Conclusions: Serum B2M level is elevated in HCV related chronic liver diseases and may be used as a marker for HCV disease progression towards cirrhosis and carcinoma.

• Tuberculosis and Respiratory Diseases
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• v.49 no.2
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• pp.207-216
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• 2000

Background : The occurrence of lung complications after allogenic bone marrow transplantation(BMT) has been reported as 40-60 percent. The risk factors for lung complications are whole body irradiation, high dose chemotherapy, graft versus host disease, old age and CMV infection. The prevalence of graft versus host disease is less in Korea than in Western countries, but frequency of CMV infection is higher. Therefore, the pattern of lung complications may be different in Korea from those in Western countries. Methods : A retrospective cohort study was performed on one hundred consecutive adult patients who underwent allogenic bone marrow transplantation from December, 1993 to May, 1999 at Asan Medical Center. Lung complications were divided into two groups by the time of development, within 30days (pre-engraftment) and beyond 30 days (post-engraftment), and then subdivided into infectious and non-infectious complication. Infectious complications were defined as having the organism in blood, BAL fluid, pleural fluid or sputum, or compatible clinical findings in patients, which improved with antibiotics or an anti-fungal therapy. Result: 1) Eighty three episodes of lung complications had occurred in 54 patients. 2) Within thirty days after BMT, non-infectious complications were more common than infections, but this pattern was reversed after 30 days. After one year post-BMT, there was no infectious complication except in cases of recurrence of underlying disease or development of chronic GVHD. 3) Among the non-infectious complications, pleural effusion (27 episodes) was most common, followed by pulmonary edema (8 episodes), bronchiolitis obliterans(2 episodes), diffuse alveolar hemorrhage (1 episode) and bronchiloitis obliterans with organizing pneumonia (1 episode). 4) The infectious complications were pneumonia (bacterial: 9 episodes, viral: 4 episodes, fungal : 5 episodes, pneumocystis carinii : 1 episode), pulmonary tuberculosis(3 episodes) and tuberculous pleurisy (3 episodes). 5) Lung complications were more frequent in CMV positive patients and in patients with delayed recovery of neutrophil count. 6) The mortality was higher in the patients with lung complications. Conclusion : Lung complications developed in 54% after allogenic BMT and were associated with higher mortality.

• Tuberculosis and Respiratory Diseases
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• v.85 no.1
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• pp.37-46
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• 2022

Background: Although respiratory tract infection is one of the most important factors triggering acute exacerbation of chronic obstructive pulmonary disease (AE-COPD), limited data are available to suggest an epidemiologic pattern of microbiology in South Korea. Methods: A multicenter observational study was conducted between January 2015 and December 2018 across 28 hospitals in South Korea. Adult patients with moderate-to-severe acute exacerbations of COPD were eligible to participate in the present study. The participants underwent all conventional tests to identify etiology of microbial pathogenesis. The primary outcome was the percentage of different microbiological pathogens causing AE-COPD. A comparative microbiological analysis of the patients with overlapping asthma-COPD (ACO) and pure COPD was performed. Results: We included 1,186 patients with AE-COPD. Patients with pure COPD constituted 87.9% and those with ACO accounted for 12.1%. Nearly half of the patients used an inhaled corticosteroid-containing regimen and one-fifth used systemic corticosteroids. Respiratory pathogens were found in 55.3% of all such patients. Bacteria and viruses were detected in 33% and 33.2%, respectively. Bacterial and viral coinfections were found in 10.9%. The most frequently detected bacteria were Pseudomonas aeruginosa (9.8%), and the most frequently detected virus was influenza A (10.4%). Multiple bacterial infections were more likely to appear in ACO than in pure COPD (8.3% vs. 3.6%, p=0.016). Conclusion: Distinct microbiological patterns were identified in patients with moderate-to-severe AE-COPD in South Korea. These findings may improve evidence-based management of patients with AE-COPD and represent the basis for further studies investigating infectious pathogens in patients with COPD.