Genetic and pathogenic characteristics of H1 avian and swine influenza A viruses

This study examined the potential for cross-species transmission of influenza viruses by comparing the genetic and pathogenic characteristics of H1 avian influenza viruses (AIVs) with different host origins in Korea. Antigenic and phylogenetic analyses of H1 AIVs circulating in Korea provided evidence of genetic similarity between viruses that infect domestic ducks and those that infect wild birds, although there was no relationship between avian and swine viruses. However, there were some relationships between swine and human viral genes. The replication and pathogenicity of the H1 viruses was assessed in chickens, domestic ducks and mice. Viral shedding in chickens was relatively high. Virus was recovered from both oropharyngeal and cloacal swabs up to 5–10 days post-inoculation. The titres of domestic duck viruses in chickens were much higher than those of wild-bird viruses. Both domestic duck and wild-bird viruses replicated poorly in domestic ducks. None of the swine viruses replicated in chickens or domestic ducks; however, six viruses showed relatively high titres in mice, regardless of host origin, and induced clinical signs such as ruffled fur, squatting and weight loss. Thus, although the phylogenetic and antigenic analyses showed no evidence of interspecies transmission between birds and swine, the results suggest that Korean H1 viruses have the potential to cause disease in mammals. Therefore, we should intensify continuous monitoring of avian H1 viruses in mammals and seek to prevent interspecies transmission.

Highly pathogenic avian influenza virus (H5N8) in domestic poultry and its relationship with migratory birds in South Korea during 2014

Highly pathogenic H5N8 avian influenza viruses (HPAIVs) were introduced into South Korea during 2014, thereby caused outbreaks in wild birds and poultry farms. During the 2014 outbreak, H5N8 HPAIVs were isolated from 38 wild birds and 200 poultry farms (up to May 8, 2014). To better understand the introduction of these viruses and their relationships with wild birds and poultry farm, we analyzed the genetic sequences and available epidemiological data related to the viruses. Genetic analysis of 37 viruses isolated from wild birds and poultry farms showed that all of the isolates belonged to clade 2.3.4.6 of the hemagglutinin (HA) gene, but comprised two distinct groups. During the initial stage of the outbreak, identical isolates from each group were found in wild birds and poultry farms near Donglim Reservoir, which is a resting site for migratory birds, thereby indicating that two types of H5N8 HPAIVs were introduced into the lake at the same time. Interestingly, the one group of H5N8 HPAIV predominated around Donglim Reservoir, and the predominant virus was dispersed by wild birds among the migratory bird habitats in the western region of South Korea as time passed, and it was also detected in nearby poultry farms. Furthermore, compared with the results of the annual AIV surveillance of captured wild birds, which has been performed since 2008, more HPAIVs were isolated and H5 sero-prevalence was also detected during the 2014 outbreak. Overall, our results strongly suggest that migratory birds played a key role in the introduction and spread of viruses during the initial stage of the 2014 outbreak.

Development and characterization of mouse monoclonal antibodies reactive with chicken IL-1β

Interleukin-1β proteins from chicken, duck, goose, turkey, and pigeon share 77 to 99% amino acid sequence similarity among themselves, and only 31 to 35% sequence similarity is shared between avian and mammalian IL-1β. There have been no antibodies that specifically detect avian IL-1β, and the current study was conducted to develop mouse monoclonal antibodies (mAb) against chicken IL-1β (chIL-1β) to further define its biochemical and immunological properties. In this study, 2 mouse mAb that are specific for chIL-1β were produced and characterized. Both mAb identified a 66.0 kDa recombinant chIL-1β protein expressed in Escherichia coli by Western blot analysis that corresponded to the expected molecular weight of a recombinant fusion protein containing the full-length 23.0 kDa chIL-1β protein and a 43.0 kDa maltose binding protein tag. Immunohistochemical analysis identified cells producing endogenous chIL-1β in the cecal tonsils, bursa of Fabricius, and spleen. Purified recombinant chIL-1β dose-dependently stimulated the proliferation and nitric oxide production by thymocytes, and both activities were inhibited by co-incubation with the 2 chIL-1β mAb described in this paper. These mAb will be important immune reagents for basic and applied poultry research of IL-1β in poultry.

Effects of in ovo injection with selenium on immune and antioxidant responses during experimental necrotic enteritis in broiler chickens

This study was conducted to investigate the effects of in ovo injection of Se on modulating the immune system and antioxidant responses in broiler chickens with experimental necrotic enteritis. Broiler eggs were injected at 18 d of embryo age with either 100 μL of PBS alone or sodium selenite (Na2SeO3) in PBS, providing 0 (SS0), 10 (SS10), or 20 (SS20) μg of Se/egg. At 14 d posthatch, PBS-treated and uninfected chickens were kept as the control group, whereas the remaining chickens were orally infected with 1.0 × 10(4) sporulated oocysts of Eimeria maxima (SS0, SS10, SS20). At 18 d posthatch, E. maxima-infected chickens were orally infected with 1.0 × 10(9) cfu of Clostridium perfringens. Infected control SS0 group showed significantly decreased BW compared with the uninfected control. However, SS20 group showed significantly increased BW compared with the infected control SS0 group, whereas the BW were similar among uninfected control and infected SS10 and SS20 groups. The SS10 group showed significantly lower intestinal lesions compared with the SS0 group, and oocyst production was decreased in both SS10 and SS20 groups. Serum malondialdehyde level and catalase activity were also decreased in both SS10 and SS20 groups, whereas the superoxide dismutase level was significantly lower in the SS10 group compared with the SS0 group. The SS20 group showed significantly higher levels of transcripts for IL-1β and IL-6 in intestine, and SS10 and SS20 groups had higher levels of transcripts for IL-8 and inducible nitric oxide synthase expression and decreased glutathione peroxidase 7 mRNA levels compared with the SS0 group. The SS10 and SS20 groups also showed increased serum antibody levels to C. perfringens α-toxin and NetB toxin compared with the SS0 group. These collective results suggest that the injection of Se into the amniotic cavity of developing eggs may be beneficial for enhancing immune and antioxidant responses in the hatched chickens exposed to the necrotic enteritis-causing pathogens.

Identification of a novel HLA-B allele, B*46:39, by sequence-based typing

The new allele B*46:39 showed a single-nucleotide substitution compared with B*46:01 at codon 185 (CCA/ACA).

Comparison of clinical outcomes after conservative and surgical treatment of isolated anastomotic leaks after esophagectomy for esophageal cancer

The clinical course and outcome of isolated anastomotic leaks (IALs) after esophagectomy are significantly different from those of necrotic leaks. The purpose of this study was to investigate the clinical features, diagnosis, treatment, and long-term outcome in patients with IALs after esophagectomy with reconstruction for esophageal cancer. A total of 663 patients underwent esophagectomy with esophageal reconstruction because of esophageal cancer between 2000 and 2010 at the Seoul Asan Medical Center. IALs occurred in 23 patients (3.5%). All patients with IAL were male, with a median age of 61 years. Patients with IAL were divided into three groups based on their clinical course. group A comprised patients who had definite clinical symptoms and/or signs indicating mediastinal contamination or leak before routine contrast esophagography was performed. Groups B and C comprised patients who had no definite clinical symptoms and/or signs of leaks before the routine contrast examination. Furthermore, group B contained those patients who resumed oral intake because no leak was found in the routine contrast examination and was diagnosed some days after resuming oral intake. Group C contained those patients who kept fasting because the leak was found in the routine contrast examination. The median follow-up period was 30 months. The mean time to closure of the IAL was 70.1 ± 96.0 days (range 4-364). There was a 72.7% overall closure rate within 60 days. By univariate analysis, the mean time to closure of the IAL was found to be significantly longer for group A patients or in cases where the patients had an uncontained leak, leukocytosis, or empyema. However, there was no statistically significant differences in age, neoadjuvant treatment, site of anastomosis (cervical vs. thoracic), fever, or treatment of the leak. By multivariate analysis, group A was found to be an independent predictive factor for the time to closure of the IAL. Repeat contrast studies revealed no anastomotic leaks in 18 patients and the formation of contained fistula in four cases (excluding one patient who died in hospital). The four patients with a contained fistula showed no clinical symptoms or signs, and tolerated resumed oral intake. IALs were resolved in most cases with low leak-related mortality, and resolution of the leaks occurred within 2 months in the majority of patients.

Long-term results of thoracoscopic thymectomy for thymoma without myasthenia gravis

OBJECTIVE

To compare the feasibility and safety of thoracoscopic thymectomy with conventional sternotomy thymectomy for thymoma without myasthenia gravis.

METHODS

Data from 70 patients diagnosed with thymoma, who underwent thoracoscopic thymectomy (n = 25, Group T) or sternotomy thymectomy (n = 45, Group S) between March 2002 and March 2008, were retrospectively evaluated.

RESULTS

Mean follow-up durations were 78.0 ± 21.9 months and 70.0 ± 23.6 months in Groups T and S, respectively. No deaths occurred in Group T; seven deaths occurred in Group S, all > 1 month post follow-up. Durations of chest intubation and hospitalization were significantly shorter in Group T than in Group S. No significant between-group difference in the incidence of operative complications was observed. Tumour recurrence-free rates at 5 and 7 years postsurgery were 96% (both years) in Group T and 95% (both years) in Group S.

CONCLUSIONS

Long-term follow-up indicates that thoracoscopic thymectomy for thymoma without myasthenia gravis is effective and is well tolerated, and associated with low rates of operative complications and recurrence.

The frequency and impact of ROS1 rearrangement on clinical outcomes in never smokers with lung adenocarcinoma

BACKGROUND

To determine the frequency and predictive impact of ROS1 rearrangements on treatment outcomes in never-smoking patients with lung adenocarcinoma.

PATIENTS AND METHODS

We concurrently analyzed ROS1 and ALK rearrangements and mutations in the epidermal growth factor receptor (EGFR), and KRAS in 208 never smokers with lung adenocarcinoma. ROS1 and ALK rearrangements were identified by fluorescent in situ hybridization.

RESULTS

Of 208 tumors screened, 7 (3.4%) were ROS1 rearranged, and 15 (7.2%) were ALK-rearranged. CD74-ROS1 fusions were identified in two patients using reverse transcriptase-polymerase chain reaction. The frequency of ROS1 rearrangement was 5.7% (6 of 105) among EGFR/KRAS/ALK-negative patients. Patients with ROS1 rearrangement had a higher objective response rate (ORR; 60.0% versus 8.5%; P = 0.01) and a longer median progression-free survival (PFS; not reached versus 3.3 months; P = 0.008) to pemetrexed than those without ROS1/ALK rearrangement. The PFS to EGFR-tyrosine kinase inhibitors in patients harboring ROS1 rearrangement was shorter than those without ROS1/ALK rearrangement (2.5 versus 7.8 months; P = 0.01).

CONCLUSIONS

The frequency of ROS1 rearrangements in clinically selected patients is higher than that reported for unselected patients, suggesting that ROS1 rearrangement is a druggable target in East-Asian never smokers with lung adenocarcinoma. Given the different treatment outcomes to conventional therapies and availability of ROS1 inhibitors, identification of ROS1 rearrangement can lead to successful treatment in ROS1-rearranged lung adenocarcinomas.

Application of real-time reverse transcription polymerase chain reaction to the detection the matrix, H5 and H7 genes of avian influenza viruses in field samples from South Korea

BACKGROUND

The rapid and accurate identification of the H5 and H7 subtypes of avian influenza (AI) virus is an important step for the control and eradication of highly pathogenic AI outbreaks and for the surveillance of AI viruses that have the potential to undergo changes in pathogenicity in poultry and wild birds. Currently, real-time reverse transcription polymerase chain reaction (RRT-PCR) is routinely used for the rapid detection of the H5 and H7 genes, but misidentification is frequent for emergent isolates and viruses isolated from diverse regions due to the high sequence variation among AI viruses.

FINDINGS

In this study, an RRT-PCR method was tested for the detection of matrix, H5 and H7 genes from diverse subtypes of AI viruses and from field samples obtained through AI surveillance in South Korea over the last four years. Both RRT-PCR and conventional experiment (virus isolation using egg inoculation followed by reverse transcription polymerase chain reaction) agreed on the virus-positive samples. And the comparison of the results with 174 clinical samples showed a high level of agreement without decreasing the specificity and sensitivity.

CONCLUSIONS

This assay could be useful tool for the rapid detection of AI using the field samples from domestic poultry and wild birds in South Korea, and continuous regional updates is needed to validate primer sets as the AI virus evolves.

Clinicopathological characteristics of T1 colorectal cancer without background adenoma

AIM

Background adenoma (BGA) is defined as benign adenomatous tissue contiguous to resected carcinomas, and the absence of BGA in a tumour is considered a histological criterion of de novo cancers. The present study aimed to identify the clinicopathological characteristics of T1 colorectal cancer (CRC) without BGA.

METHOD

A retrospective review was carried out of prospectively collected data from two centres: the National Cancer Center, Korea; and Chonnam National University Hwasun Hospital, Korea. A total of 590 patients with T1 CRC, treated by endoscopic or surgical resection between January 2001 and August 2011, were enrolled. Details regarding gender, age, tumour location, endoscopic gross type, tumour size, depth of submucosal (SM) invasion, angiolymphatic invasion, tumour grade, budding and lymph node (LN) metastasis were evaluated with regard to the presence or absence of BGA.

RESULTS

BGA was absent in 197 (33.4%) patients. Tumour size <20 mm, flat or depressed type, deep SM depth and tumour budding were associated with the absence of BGA in univariate and multivariate analyses (P < 0.05). In surgically resected patients, LN metastases were significantly associated with the absence of BGA (P = 0.022).

CONCLUSION

T1 CRC without BGA presented several characteristics of small size (<20 mm), flat or depressed type, deep SM depth (SM 2/3), LN metastasis and tumour budding. These results indicate that de novo cancers may have a more invasive potential.

Immature Rubus coreanus Shows a Free Radical-Scavenging Effect and Inhibits Cholesterol Synthesis and Secretion in Liver Cells

Rubus coreanus fruits have been employed as a traditional medicine for centuries in the Asia-Pacific region. Its pharmacological action differs according to the different extraction methods utilized and the degree of fruit ripening. In this study, we determined the cellular effect of different ethanol extracts of mature and immature Rubus coreanus fruits in human hepatic cell line, HepG2 cells. The antioxidant activity, effect on superoxide dismutase activity and cholesterol biosynthesis efficiency was also evaluated. Immature Rubus coreanus extract showed higher antioxidant capability, compared with that of its mature fractions. Cellular antioxidant proteins including HO-1, Cu/Zn-superoxide dismutase and catalase were highly expressed in the presence of Rubus coreanus. Cholesterol levels in HepG2 cells treated with the water fraction of immature Rubus coreanus were significantly reduced. This antihyperlipidaemic action of Rubus coreanus is a consequence of cholesterol biosynthesis and extracellular secretion in HepG2 cells. These results indicate that among different ethanol fraction of mature and immature Rubus coreanus fruit extracts, water extract of immature fruit extract shows higher antioxidant as well as higher antihyperlipidaemic action.

An extended medial to lateral approach to mobilize the splenic flexure during laparoscopic low anterior resection

AIM

The aim of this retrospective study of laparoscopic low anterior resection was to compare splenic flexure mobilization (SFM) carried out by an extended medial to lateral approach with that by a lateral approach.

METHOD

Records of patients with rectal cancer on a prospectively maintained database undergoing laparoscopic low anterior resection performed between January 2009 and November 2011 by a single surgeon were analysed. The extended medial to lateral approach involved continuing the medial to lateral approach upwards to enter the lesser sac over the pancreas, thus permitting detachment of the splenic flexure.

RESULTS

Two hundred and thirty-seven patients, including 164 undergoing a lateral SFM and 73 an extended medial to lateral SFM, were evaluated. Both patient groups had similar characteristics except for operative time (152.7 ± 32.7 min extended medial to lateral; 171.5 ± 40.8 min lateral; P < 0.001), postoperatively the interval to oral intake (3.1 ± 0.8 days extended medial to lateral; 3.7 ± 0.9 lateral; P < 0.001) and duration of hospital stay (8.2 ± 2.8 days extended medial to lateral; 10.3 ± 7.5 days lateral; P = 0.002) favoured the extended medial to lateral group.

CONCLUSION

An extended medial to lateral approach for SFM during laparoscopic low anterior resection of rectal cancer appears to be an improvement over the previously used lateral approach, because it may provide a shorter operation time and shorter hospital stay.

Application of transanal irrigation for patients with spinal cord injury in South Korea: a 6-month follow-up study

STUDY DESIGN

A 6-month follow-up study.

OBJECTIVES

To investigate the outcome of transanal irrigation (TAI) in patients with spinal cord injury (SCI) and to identify factors significantly related to clinical success.

SETTING

Survey for community-dwelling patients with SCI in South Korea.

METHODS

Between December 2010 and March 2012, TAI was initiated with 52 patients (41 men; age: 44.5±11.0 years) with neurogenic bowel dysfunction (NBD). At 1, 3 and 6 months after initiation, a telephone interview was conducted. Data were collected on patient-specific bowel management and TAI performance as a new procedure.

RESULTS

Only 18 patients (34%) used TAI for at least 6 months, which was a lower compliance rate than similar studies in some European countries. Relative to the compliant group, the noncompliant group contained a higher proportion of tetraplegia than paraplegia (P=0.031), and a higher proportion dependent on physical help (P=0.034). In all, 33 of the 52 patients (63.5%) complained of practical problems with the TAI procedure such as expulsion of the rectal catheter. Fifteen patients (28.8%) presented with adverse effects. The incidence of practical problems or adverse effects did not alter the frequency of patient-reported successful outcome.

CONCLUSION

Korean participants showed a relatively lower compliance rate with TAI. We conclude that TAI, combined with adequate patient instruction and physical assistance, has potential as a management tool for NBD in Korea.

Upregulation of stromal cell-derived factor by IL-17 and IL-18 via a phosphatidylinositol 3-kinase-dependent pathway

Th17 cells that produce interleukin (IL)-17 play a key role in the pathogenesis of autoimmune inflammation. Among the various cytokines that are involved in the IL-17 pathway, members of the IL-1β family, including IL-18, have recently gained attention. In this study, we stimulated synovial fibroblasts with a combination of IL-17 and IL-18 and quantified their stromal cell-derived factor-1 (SDF-1) production by enzyme-linked immunosorbent assay and their transcript levels by reverse transcription-polymerase chain reaction. Both IL-17 and IL-18 significantly increased the level of SDF-1, not only individually but also synergistically (P< 0.05). The synergism was effectively suppressed by anti-IL-17 and -IL-18 antibodies, and a PI3K inhibitor. To the best of our knowledge, this is the first report of PI3K-dependent synergism between IL-18 and IL-17, and this work adds a novel perspective of the role of IL-18 in immune regulation. The individual effects of these two cytokines, and their interactions, suggest an interrelationship between the IL-1 family and IL-17.

Comparative proteome and transcriptome analyses of wild-type and live vaccine strains of Salmonella enterica serovar Gallinarum

Salmonella enterica serovar Gallinarum causes fowl typhoid in chickens and is of economic importance to the chicken industry. A serovar Gallinarum live vaccine strain 9R (SG 9R) has been used to control fowl typhoid in many areas where the disease is endemic. Because the attenuation mechanism of SG 9R was not defined, there has been continued concern about reversion to virulence. In this study, we examined the molecular characteristics, which might provide better insight into attenuation of SG 9R, by comparing its proteome and transcriptome with those of two wild-type strains (287/91 and 06Q110). Proteins present in wild-type strains but absent in SG 9R were identified by two-dimensional gel electrophoresis and MALDI-TOF MS. Genes up- or down-regulated in SG 9R compared to wild-type strains were identified using an expression array. The proteome analysis identified nine proteins absent in SG 9R of which one protein had relevance to virulence. The transcriptome analysis revealed 24 up-regulated and 97 down-regulated genes in SG 9R. Approximately one-half of down-regulated genes (42 genes) were associated with virulence mechanisms. This finding suggests that attenuation of SG 9R may be associated with a combination of impaired virulence factors and thus reversion to virulence would not be caused by any single mutation event.

Serosurveillance for Japanese encephalitis virus in wild birds captured in Korea

Climate change induced by recent global warming may have a significant impact on vector-borne and zoonotic diseases. For example, the distribution of Japanese encephalitis virus (JEV) has expanded into new regions. We surveyed the levels of hemagglutination-inhibition (HI) antibodies against JEV (Family Flaviviridae, genus Flavivirus) in wild birds captured in Korea. Blood samples were collected from 1,316 wild birds including the following migratory birds: Oceanodroma castro (n = 4), Anas formosa (n = 7), Anas penelope (n = 20), Fulica atra (n = 30), Anas acuta (n = 89), Anas crecca (n = 154), Anas platyrhynchos (n = 214), Aix galericulata (n = 310), and Anas poecilorhyncha (n = 488). All were captured in 16 locations in several Korea provinces between April 2007 and December 2009. Out of the 1,316 serum samples tested, 1,141 (86.7%) were positive for JEV. Wild birds captured in 2009 had a higher seroprevalence of ant-JEV antibodies than those captured in 2007. Wild birds with an HI antibody titer of 1 : 1,280 or higher accounted for 21.2% (280/1,316) of the animals tested. These findings indicated that wild birds from the region examined in our study have been exposed to JEV and may pose a high risk for introducing a new JEV genotype into Korea.

Isolation of a reassortant H13N2 virus from a mallard fecal sample in South Korea

Background

Virus subtype H13N2, A/mallard/Kr/SH38-45/2010 (H13N2), was first isolated from a mallard fecal sample in South Korea.

Results

Phylogenetic analysis of all eight viral genes revealed that this virus emerged by genetic mixing between Eurasian and North American gene pools, and possibly between wild ducks and gulls. The H13 and N2 surface genes clustered together in a group with Eurasian isolates from gulls and wild birds, respectively. The PB2, PA, NP, M and NS segments belonged to the Eurasian lineage, whereas the PB1 gene clustered in the North American lineage. Furthermore, they showed a bird-dependent pattern in phylogenetic analysis: the M gene was similar to subtype H13 viruses within gulls, whereas other segments were similar to avian influenza viruses of other subtypes from wild ducks.

Conclusions

The data suggests that the novel reassortant H13N2 virus isolated in South Korea might have emerged by genetic reassortment between intercontinental and interspecies transmission in wild birds.