Molecular Evolution of Infectious Pancreatic Necrosis Virus in China.

Passive virus surveillance was performed in twenty-nine salmon and trout farms from seven provinces and districts in China during the period 2017-2020. A total of 25 infectious pancreatic necrosis virus (IPNV) isolates were obtained, mainly from rainbow trout (Oncorhynchus mykiss). The molecular evolution of these Chinese IPNV isolates and the previously reported Chinese IPNV strains ChRtm213 and WZ2016 was analyzed, based on their VP2 gene coding region sequences (CDS). All 27 Chinese IPNV isolates clustered within genogroups I and V, with 24 of the IPNV isolates belonging to genogroup I (including ChRtm213 and WZ2016), and only three isolates clustering in genogroup V. The Chinese genogroup I IPNV isolates lacked diversity, composing six haplotypes with 41 polymorphic sites, and the identity of nucleotide and amino acid sequences among the entire VP2 gene CDS from these isolates was 97.44%-100% and 98.19%-100%, respectively. Divergence time analyses revealed that the Chinese genogroup I IPNV isolates likely diverged from Japanese IPNV isolates in 1985 (95% highest posterior density (HPD), 1965-1997), and diverged again in 2006 (95% HPD, 1996-2013) in China. Each of the three Chinese genogroup V IPNV isolates has a unique VP2 gene CDS, with a total of 21 polymorphic sites; the identity of nucleotide and amino acid sequences among all VP2 gene CDS from these isolates was 98.5%-99.5% and 98.6%-99.0%, respectively. The data demonstrate that genogroups I and V are more likely the currently prevalent Chinese IPNV genotypes.

Development of a Colloidal Gold Immunochromatographic Strip for the Rapid Detection of Channel Catfish Virus.

BACKGROUND: Channel catfish virus disease (CCVD) has resulted in great economic losses and has restricted the development of fisheries. There is therefore, a need for rapid and efficient diagnostic methods to control the spread of CCVD. OBJECTIVE: A colloidal gold immunochromatographic strip has been developed for the detection of CCVD. METHODS: In this study, a colloidal gold immunochromatographic strip for channel catfish virus (CCV) detection was developed using the monoclonal antibody 8B6 conjugated with colloidal gold as the detector antibody. A rabbit anti-CCV antibody was used as the capture complex at the test line, and a goat anti-mouse IgG antibody was used as the capture antibody at the control line. The strip was characterized in its specificity, sensitivity, and stability. In addition, an infection experiment was performed to test the applicability of the test strip. RESULT: The strip was able to detect concentrations of the virus (104 tissue culture infective dose (TCID50)/mL) and showed analytical specificity when tested against other viral pathogens. The strips were still usable after 30 days of storage at 60°C. It was possible to detect CCV experimentally in infected fish within 10-15 min of using the strip. CONCLUSIONS: The strip can be used as a rapid and convenient tool for on-site diagnosis to control outbreaks and the spread of CCVD. HIGHLIGHTS: The immunochromatographic strip was the first to be developed and applied for the detection of CCVD.

Downregulation of PSCA promotes gastric cancer proliferation and is related to poor prognosis.

Background: Dysregulation of prostate stem cell antigen (PSCA) has been implicated in human cancers. Studies have reported that PSCA expression is generally high in prostate cancer, which correlates with a worse survival. PSCA is also highly expressed in bladder, ovarian, and pancreatic cancers. However, PSCA is expressed at low levels in gastric, gallbladder and oesophageal cancers. At present, the clinical significance, expression pattern and biological function of PSCA in gastric cancer (GC) are still unclear. Methods: Previously, we used cDNA microarray as a screening tool to compare GC tissues with its matched normal gastric mucosa tissues (MNGT), and obtained the differentially expressed genes of the two tissue types. PSCA is one of the genes significantly down-regulated in GC tissues. In this study, we detected the expression of PSCA in GC tissues and MNGT by western-blot experiment and immunohistochemical staining (IHC). Then the relationship between the expression pattern of PSCA and the clinicopathological characteristics and survival in GC was analyzed. In order to further study the function of PSCA in GC, lentivirus was used to construct stable cell lines with knockdown and overexpression of PSCA gene. We used AGS and MKN45 cell lines for plasmid transfection. Colony formation assay, MTS and nude mice xenograft model were performed to investigate the effect of PSCA in GC. Results: Western-blot and IHC assays demonstrated that the expression of PSCA in GC tissues was significantly lower than that in the MNGT. PSCA expression in GC tissues was high in 252 (57.5%) and low in 186 (42.5%) of 438 patients. PSCA expression for MNGT was high in 273 (62.3%) and low in 165 (37.7%) of 438 patients. PSCA expression was significantly associated with T classification (P=0.024), N classification (P=0.018) and TNM stage (P=0.019) using χ2 test. The relationship between PSCA expression level and patient survival was analysed using Kaplan-Meier analysis and the log-rank test. Low levels of PSCA expression were significantly associated with a poorer OS than high expression levels of PSCA (P=0.011). In the COX regression analysis of OS, all 9 variables in the univariate analysis were significantly correlated with OS (P<0.05), while the variables found to be independently correlated with OS in the multivariate analysis were PSCA expression (P=0.036), age (P<0.001), gender (P=0.007), and TNM stage (P<0.001), respectively. Univariate and multivariate analyses showed that PSCA was an independent prognostic factor for OS in GC. In vitro MTS cell proliferation experiment and clonal formation experiment and in vivo nude mouse subcutaneous tumorigenesis experiment all proved that knockdown of PSCA gene can improve the proliferation ability of GC cells, while in vitro experiment proved that overexpression of PSCA can reduce the proliferation ability of GC cells.It was found that knockdown of PSCA gene can improve the proliferation ability of GC cells both in vitro and in vivo, while overexpression of PSCA can reduce the proliferation ability of GC cells in vitro. Conclusion: Our study showed that the expression of PSCA gene was decreased in GC, which was related to more advanced pathological stages. And the expression level of PSCA in GC was an independent good prognostic factor. PSCA gene had the function of inhibiting GC proliferation.

A homogenized approach to classify advanced gastric cancer patients with limited and adequate number of pathologically examined lymph nodes.

BACKGROUND: The prognosis of gastric cancer patients with a limited number of pathologically examined lymph nodes (eLN, < 16) is dismal compared to those with adequately eLN (≥ 16), yet they are still classified within the same subgroups using the American Joint Committee on Cancer (AJCC) staging system. We aimed at formulating an easy-to-adopt and clinically reliable stratification approach to homogenize the classification for these two categories of patients. METHODS: Patients staged according to the 8th AJCC pathological nodal (N) and tumor-node-metastasis (TNM) classification were stratified into a Limited and Adequate eLN cohort based on their number of pathologically examined LNs. The statistical differences between the 5-year overall survival (OS) rates of both cohorts were determined and based on which, patients from the Limited eLN cohort were re-classified to a proposed modified nodal (N') and TNM (TN'M) classification, by matching their survival rates with those of the Adequate eLN cohort. The prognostic performance of the N' and TN'M classification was then compared to a formulated lymph-node-ratio-based nodal classification, in addition to the 8th AJCC N and TNM classification. RESULTS: Significant heterogeneous differences in 5-year OS between patients from the Limited and Adequate eLN cohort of the same nodal subgroups were identified (all P < 0.001). However, no significant differences in 5-year OS were observed between the subgroups N0, N1, N2, and N3a of the Limited eLN cohort when compared with N1, N2, N3a, and N3b from the Adequate eLN cohort, respectively (P = 0.853, 0.476, 0.114, and 0.230, respectively). A novel approach was formulated in which only patients from the Limited eLN cohort were re-classified to one higher nodal subgroup, denoted as the N' classification. This re-classification demonstrated superior stratifying and prognostic ability as compared to the 8th AJCC N and lymph-node-ratio classification (Akaike information criterion values [AIC]: 12,276 vs. 12,358 vs. 12,283, respectively). The TN'M classification also demonstrated superior prognostic ability as compared to the 8th AJCC TNM classification (AIC value: 12,252 vs. 12,312). CONCLUSION: The proposed lymph node classification approach provides a clinically practical and reliable technique to homogeneously classify cohorts of gastric cancer patients with limited and adequate number of pathologically examined lymph nodes.

Glasgow Prognostic Score is superior to ECOG PS as a prognostic factor in patients with gastric cancer with peritoneal seeding.

The Glasgow Prognostic Score (GPS) has been shown to be associated with survival rates in patients with advanced cancer. The present study aimed to compare the GPS with the Eastern Cooperative Oncology Group Performance Status (ECOG PS) in patients with gastric cancer with peritoneal seeding. For the investigation, a total of 384 gastric patients with peritoneal metastasis were retrospectively analyzed. Patients with elevated C-reactive protein (CRP; >10 mg/l) and hypoalbuminemia (<35 mg/l) were assigned a score of 2. Patients were assigned a score of 1 if presenting with only one of these abnormalities, and a score of 0 if neither of these abnormalities were present. The clinicopathologic characteristics and clinical outcomes of patients with peritoneal seeding were analyzed. The results showed that the median overall survival (OS) of patients in the GPS 0 group was longer, compared with that in the GPS 1 and GPS 2 groups (15.50, vs. 10.07 and 7.97 months, respectively; P<0.001). No significant difference was found between the median OS of patients with a good performance status (ECOG <2) and those with a poor (ECOG ≥2) performance status (13.67, vs. 11.80 months; P=0.076). In the subgroup analysis, the median OS in the GPS 0 group was significantly longer, compared with that in the GPS 1 and GPS 2 groups, for the patients receiving palliative chemotherapy and patients without palliative chemotherapy. Multivariate survival analysis demonstrated that CA19-9, palliative gastrectomy, first-line chemotherapy and GPS were the prognostic factors predicting OS. In conclusion, the GPS was superior to the subjective assessment of ECOG PS as a prognostic factor in predicting the outcome of gastric cancer with peritoneal seeding.

Clinicopathological Characteristics and Prognostic Value of Signet Ring Cells in Gastric Carcinoma: A Meta-Analysis.

Background and Objectives: Previous studies of the prognostic value of the signet ring cell (SRC) type have yielded inconsistent results. Therefore, the aim of the present meta-analysis is to explore the clinicopathological characteristics and prognostic value of SRCs. Methods: Relevant articles that compared SRC and non-SRC type in PubMed and Web of Science were comprehensively searched. Then, a meta-analysis was performed. Results: A total of 19 studies including 35947 cases were analyzed. Compared with non-SRC patients, SRC patients tended to be younger (WMD: -3.88, P=0.001) and predominantly female (OR: 1.60, P<0.001). Additionally, SRC patients exhibited less upper third tumor location (OR: 0.62, P<0.001) and less frequent hematogenous metastasis (OR: 0.41, P<0.001). There was no difference in overall survival (OS) between SRC and non-SRC patients in the total population (HR: 1.02, P=0.830). Early gastric cancer with SRCs was associated with better OS (HR: 0.57, P=0.002), while advanced gastric cancer with non-SRCs was associated with a worse prognosis (HR: 1.17, P<0.001). Conclusions: This meta-analysis revealed that SRC tends to affect young females and tends to be located in the middle and lower third of the stomach. Early SRCs are associated with better prognoses, while advanced SRCs are associated with worse prognoses.

Selective Gastric Cancer Patients with Peritoneal Seeding Benefit from Gastrectomy after Palliative Chemotherapy: A Propensity Score Matching Analysis.

Background: The present study aimed to explore whether gastric cancer patients with peritoneal seeding after receiving palliative chemotherapy could benefit from gastrectomy and to identify patients with peritoneal seeding who should be selected to receive gastrectomy. Methods: A total of 201 gastric cancer patients were diagnosed with peritoneal seeding and received palliative chemotherapy. Propensity score matching (PSM) was performed to balance the selection bias. Results: After PSM, compared with non-gastrectomy group, gastrectomy group had a longer median overall survival (OS) (23.60 vs. 13.80 moths; P=0.034). Patients with R0 resection had a median OS of 43.60 months compared with 11.27 months in patients who underwent R1/2 resection (P<0.001). The median OS times between the R1/2 resection and non-gastrectomy groups were not different (P=0.139). Subgroup analysis revealed that only patients receiving more than 4 periods of first-line chemotherapy benefited from gastrectomy (P=0.018), whereas patients receiving 1-4 periods of first-line chemotherapy did not (P=0.275). Multivariate analysis showed that gastrectomy (P=0.012) and the period of first-line chemotherapy (P<0.001) were independent prognostic factors. The overall postoperative morbidity was 3.03% (1/33) in the gastrectomy group, and no treatment-related death was observed. Conclusions: The present study indicated that gastrectomy after palliative chemotherapy is a safe procedure and showed a survival benefit for gastric cancer patients with peritoneal seeding. Moreover, clinically curative R0 gastrectomy and more than 4 periods of palliative chemotherapy resulted in better clinical outcomes.

Endoscopic ultrasonography compared with multidetector computed tomography for the preoperative staging of gastric cancer: a meta-analysis.

BACKGROUND: The current study sought to perform a meta-analysis to compare the preoperative staging of endoscopic ultrasonography (EUS) and multidetector computed tomography (MDCT) in gastric carcinoma. METHODS: Articles published between January 1, 2000, and April 1, 2016, that compared EUS with MDCT were included, and data were presented as 2 × 2 tables. The sensitivities, specificities and summary receiver operating characteristic (ROC) curves for T and N staging were calculated using a bivariate mixed effects model. Data were weighted by generic variance and then pooled by random-effects modeling. RESULTS: Eight studies comprising 1736 patients were included in this meta-analysis. For T1 staging, the sensitivity value for EUS (82%) was significantly higher than that for MDCT (41%) (relative risk (RR): 2.06, 95% confidence interval (CI) 1.07-3.94; P = 0.030). For lymph node involvement, the sensitivity value for EUS (91%) was also significantly higher than that for MDCT (77%) (RR 1.14, 95% CI 1.05-1.23; P = 0.001). However, the specificity values of both EUS and MDCT were quite low, at 49 and 63%, respectively. No significant differences in T2-4 staging between EUS and MDCT were noted. CONCLUSION: This meta-analysis indicates that EUS may be superior to MDCT in preoperative T1 and N staging. Additionally, the low specificity values of EUS and MDCT for N staging merits attention.

Establishment and characterization of a heart-derived cell line from goldfish (Carassius auratus).

The goldfish Carassius auratus, a freshwater fish in the family Cyprinidae, was one of the earliest fish to be domesticated for ornamental purposes. A cell line was established from goldfish heart (GH) tissue to create a biological monitoring tool for viral diseases. The GH cell line was optimally maintained at 25 °C in M199 medium supplemented with 10-20% fetal bovine serum. A chromosomal analysis indicated that the cell line remained diploid, with a mean chromosomal count of 100. In viral inoculation assays, significant cytopathic effects (CPEs) were caused by epizootic hematopoietic necrosis virus (EHNV), Andrias davidianus iridovirus (ADIV), and Bohle iridovirus (BIV) infections in the fish cells and the viral titers (average value) of EHNV, ADIV, and BIV in GH cells reached 105.0, 104.5, and 105.0 TCID50/0.1 mL, respectively, within 7 days. However, no CPE was observed in the cells infected with viral hemorrhagic septicemia virus (VHSV), infectious hematopoietic necrosis virus (IHNV), spring viremia of carp virus (SVCV), infectious pancreatic necrosis virus (IPNV), channel catfish virus (CCV), or grass carp reovirus (GCRV). These results suggest that the GH cell line is a valuable tool for studying viral pathogenesis.

[Isolation, identification and drug sensitivity of Streptococcus iniae from hybrid sturgeons (Huso dauricus female x Acipenser schrencki male)].

OBJECTIVE: Sturgeons were the important economic species in Beijing. In July 2012, continuous mortality of cultured hybrid sturgeons was occurred on a farm in Huairou. METHODS: We isolated three pathogens from liver, kidney and spleen of the dying sturgeons with clinical symptoms, marked HRS12718L, HRS12718K and HRS12718S respectively. Then we analyzed theirs morphological, physiological and biochemical characteristics, and drug sensitivity. We also cloned and partially sequenced the 16S rDNA of strain HRS12718K. Moreover, we identified the pathogenic characteristic of strain HRS12718K by artificial infection. RESULTS: The morphological, physiological and biochemical characteristics of three strains were consistent with that of Streptococcus iniae isolated from other fishes in China, and 16S rDNA sequence of the strain HRS12718K was more than 99.1% homology with that of Streptococcus iniae. The LD50 of the pathogen to hybrid sturgeon was 4.42 x 10(5) CFU/mL, and challenged sturgeons presented the similar signs as the natural infected sturgeons. In addition, the bacterium was sensitive to norfloxacin, enrofloxacin, neomycin sulfate, doxycyline hyclate and tetracycline hydrochloride, and was highly sensitive to enrofloxacin. CONCLUSION: Streptococcus iniae was the pathogen to cultured hybrid sturgeons in Beijing area, and enrofloxacin can be used against the disease.

[Identification and drug sensitivity of a Plesiomonas shigelloides isolated from diseased sturgeons].

OBJECTIVE: In 2012, the cumulative mortality of farmed sturgeons in Beijing was almost 60% with various symptoms, including the reddening of the anus with yellow exudation, ascities in the peritoneal cavity, petechial haemorrhages in liver and internal muscle wall, and the swollen spleen. METHODS: We isolated the pathogen from the dying sturgeons with significant pathological signs, and then analyzed its morphological, physiological and biochemical characteristics, taxonomic status, and drug sensitivity. Moreover, the pathogenic characteristic of presumptive pathogens was identified by artificial infection. RESULTS: The 16S rDNA sequence of the pathogen was more than 99% homology with that of Plesiomonas shigelloides, suggesting that the pathogen was P. shigelloides, which was also demonstrated by the results of biochemical tests. The LD50 of the pathogen to sturgeon was 1.0 x 10(5.8) CFU/mL, and it also can cause liver, kidey and spleen to lesions. There were no activities of amylase, caseinase, lipase, gelatinase and haemolysis of extracellular products of P. shigelloides, and its toxicity might be from endotoxin. In addition, the bacterium was specific sensitive to enrofloxacin, doxycyline hyclate, florfenicol and thiamphenicol with MIC less than 2 microg/mL. CONCLUSION: P. shigelloides was the main pathogen to cultured sturgeons in Beijing area, and enrofloxacin, doxycyline hyclate and florfenicol can be used against the disease.

Actinomycetes and earthy-musty odorous compounds in brackish fishponds in Tianjin, China.

The presence of the odorous compounds, 2-methylisoborneol (MIB) and geosmin, as well as causative microorganisms in brackish intensive cultivation fishponds in Tianjin, China that had a severe earthy-musty odor were evaluated. The results revealed that MIB was the primary odorous compound present in the Tianjin fishponds, with a concentration ranging from 0.53-5302.7 ng.L(-1). Furthermore, the concentration of MIB was found to be closely correlated with the gross biomass of actinomycetes in the water, which ranged from 10.67-1528.24x10(6) cfu.ml(-1). Therefore, the sequences of the 16 SrRNA and morphological characteristics of the actinomycetes in the brackish fishponds were investigated. The results revealed that the actinomycetes in the brackish fishponds included 9 species of common and dominant actinomycetes belonging to 4 genera. Of these genera, Streptomyces were the dominant species, and Streptomyces, Nocardioides and Micromonospora were the most common species in the fishponds evaluated. Next, the ability of each of the isolated Streptomyces to produce MIB was measured under laboratory culture conditions. Streptomyces Sp2 was found to have a strong ability to produce MIB, which indicates that this strain may be the primary source of the earthy-musty odor reported in brackish intensive cultivation fishponds in Tianjin, China.

[Process, mechanism, and research method of fish invasion].

Fish invasion has become a serious environmental and economic damage, and obtained a priority concern by the conservation ichthyologists and land managers. A better understanding of the invasive mechanisms is of significance in developing ecological theories and in controlling exotic pests. In this paper, the progress in studying the mechanisms of fish invasion was reviewed, involving the biological characteristics of exotic fish, their adaptive evolution, interactions among exotic and indigenous fish, and relationships between species diversity and community resistance to invasion, etc. The study of invasive process and the progress of research methods were discussed.