[MiR-300 inhibits invasion and metastasis of osteosarcoma cell MG63 by negatively regulating PTTG1]

OBJECTIVE

To investigate the effects of miR-300 and PTTG1 on osteosarcoma invasion and metastasis and explore the molecular mechanism of osteosarcoma invasion and metastasis.

OBJECTIVE

Western blot was used to detect the expression of PTTG1 in human osteoblasts hFOB1.19 and osteosarcoma cell MG63 and to detect the transfection efficiency of cells transfected with PTTG1-knockdown plasmid; Transwell invasion assay and CCK8 assay detected the effects of knockdown of PTTG1 and overexpression of miR-300 on the invasion and proliferation of osteosarcoma cell MG63. On-line prediction and screening of microRNAs (miRNAs) with complementary PTTG1 binding was conducted. qRT-PCR was performed to examine the expression of miR-300 in hFOB1.19 and MG63 cells, and Western blotting was used to detect the expression of PTTG1 in MG63 cells after transfection with a miR- 300 plasmid. Double luciferase assay was used to detect the targeted binding of miR-300 and PTTG, Transwell invasion assay and CCK8 assay were used to detect the effects of overexpression of miR-300 and overexpression of PTTG1 plasmid on invasion and proliferation of osteosarcoma cell line MG63.

OBJECTIVE

PTTG1 was highly expressed in MG63 cells (P=0.0002). PTTG1 knockdown significantly inhibited the invasion (P=0.0002) and proliferation (P=0.0039) of MG63 cells. Based on the results of online prediction of complementary miRNAs to PTTG1 and analysis of the data from NCBI database, miR-300 was determined as the target miRNA in this study. qRT-PCR results showed a significantly decreased expression of miR-300 in MG63 cells (P=0.0004). Overexpression of MiR-300 in MG63 cells significantly decreased the expression of PTTG1 (P=0.0007), and the expressions of miR-300 and PTTG1 were negatively correlated. Dual luciferase assay showed that miR-300 could specifically bind to PTTG1 (P=0.001). Overexpression of PTTG1 could significantly reverse the effect of miR-300 overexpression on invasion (P=0.0003) and proliferation (P=0.0077) of MG63 cells.

OBJECTIVE

Overexpression of miR-300 can inhibit the invasion and metastasis of osteosarcoma cell MG63 by targeting PTTG1.

Paraoxonase 2 protects against oxygen-glucose deprivation/reoxygenation-induced neuronal injury by enhancing Nrf2 activation via GSK-3β modulation

Paraoxonase 2 (PON2) is a powerful antioxidant that mediates cell survival under oxidative stress; however, its protection neurons against cerebral ischemia-reperfusion injury-induced oxidative stress remains unclear. This study aimed to determine the precise regulating role of PON2 in neuronal survival under oxidative stress. An in vitro model of cerebral ischemia-reperfusion injury was used to assess the effect of PON2 on oxidative stress induced by oxygen-glucose deprivation/reoxygenation (OGD/R). Results showed that PON2 expression in neurons was decreased due to OGD/R exposure. A series of functional experiments revealed that upregulated PON2 improved OGD/R-impaired viability and attenuated OGD/R-induced increases in apoptosis and reactive oxygen species in neurons. Decreased PON2 expression enhanced neuronal sensitivity to OGD/R-induced injury. Overexpressed PON2 markedly enhanced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) in the nucleus and increased the levels of Nrf2-mediated transcriptional activity. Furthermore, PON2 enhanced the Nrf2 activation by modulating glycogen synthase kinase-3β (GSK-3β). Inhibition of GSK-3β substantially abrogated the PON2 knockdown-mediated suppression of Nrf2 activity. Notably, Nrf2 inhibition partially reversed the neuroprotective effects of PON2 overexpression in OGD/R-exposed neurons. These findings indicate that PON2 alleviates OGD/R-induced apoptosis and oxidative stress in neurons by potentiating Nrf2 activation via GSK-3β modulation. This study highlights the potential neuroprotective function of PON2 against cerebral ischemia-reperfusion injury.

Genetic diversity and prevalence of Atypical Porcine Pestivirus in the Midwest of US swine herds during 2016-2018

Atypical porcine pestivirus (APPV), a highly divergent pestivirus, has a wide geographical distribution around the world. APPV is known to cause type A-II congenital tremors in newborn piglets. The main objective of this study is to access APPV prevalence in the US swine herds utilizing a newly developed quantitative real-time RT-PCR assay. Retrospective analysis of 1,785 samples revealed a 19.0% prevalence in Midwest swine herds over a period of three years (2016-2018). Among all clinical and field samples that were APPV positive, 82 samples (24.19%) were also positive for one or more swine viral pathogens. Two APPV US strains identified in this study demonstrated significant sequence diversity (~12% in full genome) compared to the first reported APPV strain from the United States in 2014. Of the two strains identified in this study, USA/023005/2016 is closer to two strains identified in Germany, and USA/047310/2017 shares more similarities with two US strains including Minnesota-1 and ISDVDL2014016573. Partial NS5B sequences (9127-9836 nt of the polyprotein gene) obtained from 54 APPV-positive samples revealed considerable sequence diversity, ranging from 85.8% to 100% nucleotide identity, within the US strains in samples from different geographic regions. Analysis of all US samples indicates high prevalence of APPV in Minnesota (37.35%), followed by Illinois (32.86%), Iowa (30.60%) and Kansas (21.89%). APPV was detected in 15.48% of samples assayed from 2017, slightly higher than that in 2016 (13.08%), but much lower than 2018 (28.77%). Among the various sample types tested, oral fluid samples had the highest prevalence and lowest average Ct value suggesting their suitability as a reliable diagnostic specimen for APPV detection. Overall, sequence variation among APPV strains and prevalence of the pathogen within the United States provides a basis for understanding the genetic diversity and molecular epidemiology of APPV in the US swine herds.

Identification of prognostic immune-related signature predicting the overall survival for colorectal cancer

OBJECTIVE

The morbidity and mortality of patients with colorectal cancer, one of the most common malignant tumors worldwide, is steadily increasing. The aim of this study was to investigate the association between prognostic immune-related gene profile and the outcome of colorectal cancer in patients by analyzing datasets from The Cancer Genome Atlas (TCGA).

MATERIALS AND METHODS

Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) further demonstrated that these genes were enriched in many immune-related biological processes. Univariate Cox regression analysis was applied to examine the association of immune-related genes with the prognosis in patients with colorectal cancer. The least absolute shrinkage and selection operation (LASSO) Cox regression model was then used to establish the immune-related signature for the prognostic evaluation of colorectal cancer in patients. Survival differences were assessed by the Kaplan-Meier method along with the log-rank test.

RESULTS

A total of 133 prognostic immune-related signatures were identified by using the univariate Cox proportional hazards regression analysis. A 14-gene signature-based risk score was constructed using the LASSO Cox regression. According to the cut-off of the risk-score, patients were assigned to the low-risk and high-risk groups. The log-rank test suggested that the survival time of the low-risk group was significantly higher than that of the high-risk group. In the time-dependent ROC curve analysis, the AUC for 1-year, 3-year, and 5-year overall survival (OS) were 0.781, 0.742, and 0.791, respectively. GO and KEGG analysis further revealed that the gene sets were actively involved in immune and inflammatory response, as well as the cytokine-cytokine receptor interaction pathway.

CONCLUSIONS

To summarize, we identified a novel 14-gene immune-related signature that may potentially serve as a prognostic predictor for colorectal cancer, thereby contributing to patient personalized treatment decisions. Further research needs to be conducted to validate the prognostic value of the selected genes.

Reduced serum exosomal miR-874 expression predicts poor prognosis in colorectal cancer

OBJECTIVE

Emerging evidence has indicated that serum exosomal microRNAs (miRNAs) have promising diagnostic and prognostic value for colorectal cancer (CRC). This study aimed to detect serum exosomal miR-874 expression in CRC patients and assess its potential clinical significance.

PATIENTS AND METHODS

Blood samples were collected from 125 CRC patients, 45 cases with benign adenomas (AD) and 70 healthy individuals. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to examine serum exosomal miR-874 levels.

RESULTS

The results showed that serum exosomal miR-874 levels were significantly downregulated in CRC patients compared to AD cases and healthy controls. Receiver operating characteristic (ROC) curve analysis revealed that serum exosomal miR-874 expression could discriminate CRC patients from healthy controls, as well as patients with AD. In addition, low serum exosomal miR-874 expression was associated with positive distant metastasis, positive lymph node metastasis, poor differentiation, and advanced TNM stage. Moreover, serum exosomal miR-874 expression was identified as a statistically significant independent prognostic factor for overall survival of CRC patients.

CONCLUSIONS

Collectively, serum exosomal miR-874 expression might serve as a reliable marker for CRC diagnosis and prognosis prediction.

Shiga Toxin-Producing Escherichia coli in Feces of Finisher Pigs: Isolation, Identification, and Public Health Implications of Major and Minor Serogroups†

ABSTRACT

Shiga toxin-producing Escherichia coli (STEC) are major foodborne human pathogens that cause mild to hemorrhagic colitis, which could lead to complications of hemolytic uremic syndrome. Seven serogroups, O26, O45, O103, O111, O121, O145, and O157, account for the majority of the STEC illnesses in the United States. Shiga toxins 1 and 2, encoded by stx1 and stx2, respectively, and intimin, encoded by eae gene, are major virulence factors. Cattle are a major reservoir of STEC, but swine also harbor them in the hindgut and shed STEC in the feces. Our objectives were to use a culture method to isolate and identify major and minor serogroups of STEC in finisher pig feces. Shiga toxin genes were subtyped to assess public health implications of STEC. Fecal samples (n = 598) from finisher pigs, collected from 10 pig flows, were enriched in E. coli broth and tested for stx1, stx2, and eae by a multiplex PCR (mPCR) assay. Samples positive for stx1 or stx2 gene were subjected to culture methods, with or without immunomagnetic separation and plating on selective or nonselective media, for isolation and identification of stx-positive isolates. The culture method yielded a total of 178 isolates belonging to 23 serogroups. The three predominant serogroups were O8, O86, and O121. The 178 STEC strains included 26 strains with stx1a and 152 strains with stx2e subtypes. Strains with stx1a, particularly in association with eae (O26 and O103), have the potential to cause severe human infections. All stx2-positive isolates carried the subtype stx2e, a subtype that causes edema disease in swine, but is rarely involved in human infections. Several strains were also positive for genes that encode for enterotoxins, which are involved in neonatal and postweaning diarrhea in swine. In conclusion, our study showed that healthy finisher pigs harbored and shed several serogroups of E. coli carrying virulence genes involved in neonatal diarrhea, postweaning diarrhea, and edema disease, but prevalence of STEC of public health importance was low.

HIGHLIGHTS

Development of a real-time RT-qPCR assay for the detection of porcine respirovirus 1

Porcine respirovirus 1 (PRV1) was first reported in the pig nasopharyngeal samples in Hong Kong in 2013. It has been widespread in US swine herds. Recently, PRV1 was also detected in South America and European countries. Currently, there is no validated diagnostic assay available for the detection of this virus. In this study, we developed a real-time reverse transcriptase quantitative PCR (RT-qPCR) assay targeting the hemagglutinin-neuraminidase (HN) gene for molecular diagnosis. The analytical sensitivity of this RT-qPCR assay was evaluated using in vitro transcribed RNA standard, and the limit of detection was 10 copies of viral RNA in a 20 μl reaction. No cross-reactivity was observed with nucleic acid prepared from common swine respiratory pathogens. The diagnostic performance of this assay was determined with 114 pig nasal swabs and 19 oral fluid samples with known PRV1 infection status. The RT-qPCR results were consistent with conventional RT-PCR and DNA sequencing of the HN gene, demonstrating a 100 % sensitivity and 100 % specificity. This assay was further applied to field samples. Among 310 nasal swab samples that were tested, 201 samples from 8 swine farms were PRV1 positive. No viremia was detected in PRV1 infected pigs using the available field samples. Nasal swab and oral fluid samples appear to be reliable for PRV1 detection with the RT-qPCR assay. Taken together, we developed and validated an RT-qPCR assay for accurate detection of PRV1 in nasal swab and oral fluid samples. It will be a useful tool for the rapid diagnosis of PRV1 infection and in aid of PRV1 epidemiological surveillance.

72 Young Scholar Presentation: Use of medium chain fatty acids as mitigation or prevention strategies against pathogens in swine feed

Four experiments were conducted to evaluate: 1) medium chain fatty acids (MCFA) application to swine feed pre- or post-viral contamination with porcine epidemic diarrhea virus (PEDV) measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR), 2) MCFA levels and combinations measured by qRT-PCR, and 3) selected MCFA in bioassay. In Exp. 1, treatments were a 2x2 + 1 factorial with the main effects of chemical treatment (0.3% commercial formaldehyde (CF), Sal CURB [Kemin Industries, Des Moines, IA] or 1% MCFA blend (Blend) of 1:1:1 C6:C8:C10 [PMI, Arden Hills, MN]) and timing of application pre- or post-inoculation with PEDV; plus a positive control (PC; feed inoculated with PEDV and no chemical treatment). All combinations of treatment and timing decreased detectable PEDV compared to PC (P< 0.05). Pre-inoculation had decreased PEDV detection compared to post-inoculation (P=0.009). Commercial formaldehyde decreased PEDV detection compared to MCFA (P< 0.001). In Exp. 2 and 3, pre-inoculation treatments consisted of: 1) PC, 2) 0.3% CF, and varying levels (0.125-0.66%) and combinations of MCFA (C5:0, C6:0, C8:0, or C10:0). In Exp. 2, treating feed with 0.33% C8:0 decreased (P< 0.05) PEDV detection compared to all levels of MCFA and PC. In Exp. 3, treating feed with CF, 0.5-1% Blend, all levels of C6:0+C8:0, 0.25% C6:0+C10:0, 0.33% C6:0+C10:0, 0.25% C8:0+C10:0, or 0.33% C8:0 + 0.33% C10:0 resulted in decreased PEDV detection compared to PC (P< 0.05). In Exp. 4, feed was treated pre-inoculation with either 1) no treatment (PC), 2) 0.3% CF, 3) 0.5% Blend, or 4) 0.3% C8:0 and analyzed via qRT-PCR and bioassay. Adding 0.5% Blend or 0.3% C8:0 resulted in decreased PEDV detection compared to PC. All chemical treatments resulted in no evidence of infectivity in the bioassay while the positive control did produce evidence of infectivity. In conclusion, lower levels of MCFA than previously evaluated may provide in-feed protection against PEDV.

[The effects of PDK1-Akt signaling pathway intervention on cardiomyocyte HCN4 ion channels]

Objective: To explore the effects of 3-phosphate dependent protein kinase 1-protein kinase B (PDK1-Akt) signaling pathway on the transcription, expression and function of cardiac hyperpolarized activated cyclic nucleotide gated 4 (HCN4) ion channels. Methods: Atrial myocytes were obtained from healthy male wild-type C57 mice and heart-specific PDK1 knockout mice (PDK1-KO) by enzymolysis. Then the atrial myocytes were divided into blank control group and PDK1-KO group. In further studies, the isolated atrial myocytes were cultured and further divided into drug control group (treated with dimethyl sulfoxide (DMSO)) and PDK1 knockdown group (treated with 1 μg/ml PDK1 short hairpin RNA (shRNA) interference plasmid), SC79 group (treated with 8 μmol/ml SC79), GSK2334470 group (treated with 10 nmol/L GSK2334470) and PDK1 knockdown+SC79 group (8 μmol/ml SC79 and 1 μg/ml PDK1 shRNA interference plasmid). Real time quantitative PCR (qRT-PCR) was used to detect the mRNA expression levels of PDK1 and HCN4, Western blot was used to detect the protein expression levels of PDK1, Akt and HCN4, the whole cell patch clamp was used to detecte the current density of HCN, and immunofluorescence was used to detecte the expression of HCN4 protein on atrial cells. Results: (1) the expression levels of HCN4 mRNA (1.46±0.03 vs. 0.99±0.01, P<0.001) and protein (1.14±0.02 vs. 1.00±0.06, P=0.017) in PDK1-KO group were higher than those in blank control group. The HCN current density in PDK1-KO group was higher than that in blank control group((-17.47±2.00) pA/pF vs. (-12.15±2.25) pA/pF, P=0.038). (2) The functions of PDK1 shRNA and specific Akt agonist SC79 were verified by comparing the PDK1 knockdown group and SC79 group with the drug control group. The results showed that the expression levels of PDK1 mRNA and protein in PDK1 knockdown group were lower than those in drug control group, and the expression level of phosphorylated Akt (Thr 308) protein in SC79 group was higher than that in drug control group. (3) The expression levels of HCN4 mRNA (3.61±0.46 vs. 1.00±0.08, P<0.001) and protein (2.33±0.11 vs. 1.00±0.05, P<0.001) in GSK2334470 group were higher than those in drug control group. (4) To reduce the effect of drug-miss target, the cultured atrial myocytes were transfected with shRNA plasmid of PDK1 and intervened with SC79. The results showed that the expression of HCN4 mRNA in PDK1 knockdown group was higher than that in the drug control group (1.76±0.11 vs. 1.00±0.06, P<0.001), and PDK1 knockdown+SC79 group (1.76±0.11 vs. 1.33±0.07, P=0.003). In PDK1 knockdown+SC79 group, the mRNA expression level was also higher than that in the drug control group (1.33±0.07 vs. 1.00±0.06, P<0.001). The expression level of HCN4 protein in PDK1 knockdown group was higher than that in drug control group (1.15±0.04 vs. 1.00±0.05, P=0.003). As for the The expression level of HCN4 protein, there was no significantly statistical difference between the PDK1 knockdown+SC79 group and the drug control group (P>0.05), but PDK1 knockdown+SC79 group was lower than PDK1 knockdown group (0.95±0.01 vs. 1.15±0.04, P<0.001). In patch clamp experiments, the results showed that the HCN current density was (-13.27±1.28) pA/pF in the drug control group, (-18.76±2.03) pA/pF in the PDK1 knockdown group, (-13.50±2.58) pA/pF in the PDK1 knockdown+SC79 group; the HCN current density of PDK1 knockdown group was higher than that of drug control group (P<0.001), but there was no significant difference between PDK1 knockdown+SC79 group and drug control group (P>0.05). (5) The results of immunofluorescence showed that the brightness of green fluorescence of PDK1 knockdown group was higher than that of drug control group, indicating that the expression of HCN4 localized on cell membrane was increased. However, the green fluorescence of PDK1 knockdown+SC79 group was lighter than that of PDK1 knockdown group, suggesting that the expression of HCN4 in PDK1-knockdown cell membrane decreased after further activating Akt. Conclusion: PDK1-Akt signaling pathway is involved in the regulation of HCN4 ion channel transcription, expression and function.

[Analysis of mutation site characteristics of Gilbert syndrome and Crigler--Najjar syndrome in relation to uridine diphosphate glucuronosyltransferase A1 gene]

Objective: To investigate the mutation characteristics and clinical relevance of Gilbert syndrome (GS) and Crigler-Najjar syndrome (CNS) in relation to uridine diphosphate glucuronosyltransferase A1 (UGT1A1) gene. Methods: The characteristics of UGT1A1 gene mutation and their clinical relevance were analyzed by searching PubMed and Human Gene Mutation Databases. Results: A total of 163 mutation sites were found in the UGT1A1 gene since November 16, 2018. The following patterns existed at the above sites: (1) the numbers of gene mutations occurring between different exons of UGT1A1 was related to GS or CNS phenotypes, and were positively correlated with the length of the exon; (2) nonsense point mutations was mainly occurred in type I of CNS; (3) GS, Crigler-Najjar syndrome type II compound heterozygous mutation sites had a certain combination and distribution, among which - 3279t > G mutation was found in all four GS complex heterozygous compositions; (4) UGT1A1 gene mutation sites reported in Asia had marked aggregation in c.211-c.558. Conclusion: UGT1A1 gene mutation characteristics and clinical relevance varies with different mutation sites, reporting areas and populations. This study has reference value for basic research and clinical diagnosis and treatment of GS and CNS.

Guidelines for Sanger sequencing and molecular assay monitoring

Genetic sequencing, or DNA sequencing, using the Sanger technique has become widely used in the veterinary diagnostic community. This technology plays a role in verification of PCR results and is used to provide the genetic sequence data needed for phylogenetic analysis, epidemiologic studies, and forensic investigations. The Laboratory Technology Committee of the American Association of Veterinary Laboratory Diagnosticians has prepared guidelines for sample preparation, submission to sequencing facilities or instrumentation, quality assessment of nucleic acid sequence data performed, and for generating basic sequencing data and phylogenetic analysis for diagnostic applications. This guidance is aimed at assisting laboratories in providing consistent, high-quality, and reliable sequence data when using Sanger-based genetic sequencing as a component of their laboratory services.

Suggested guidelines for validation of real-time PCR assays in veterinary diagnostic laboratories

This consensus document presents the suggested guidelines developed by the Laboratory Technology Committee (LTC) of the American Association of Veterinary Laboratory Diagnosticians (AAVLD) for development, validation, and modification (methods comparability) of real-time PCR (rtPCR) assays. These suggested guidelines are presented with reference to the World Organisation for Animal Health (OIE) guidelines for validation of nucleic acid detection assays used in veterinary diagnostic laboratories. Additionally, our proposed practices are compared to the guidelines from the Foods Program Regulatory Subdivision of the U.S. Food and Drug Administration (FDA) and from the American Society for Veterinary Clinical Pathology (ASVCP). The LTC suggestions are closely aligned with those from the OIE and comply with version 2021-01 of the AAVLD Requirements for an Accredited Veterinary Medical Diagnostic Laboratory, although some LTC recommendations are more stringent and extend beyond the AAVLD requirements. LTC suggested guidelines are substantially different than the guidelines recently published by the U.S. FDA for validation and modification of regulated tests used for detection of pathogens in pet food and animal-derived products, such as dairy. Veterinary diagnostic laboratories that perform assays from the FDA Bacteriological Analytical Method (BAM) manual must be aware of the different standard.

The obesity paradox in patients with atrial fibrillation: an insight from the Gulf SAFE registry

Background

The prognostic role of obesity among patients with atrial fibrillation (AF) is unclear.

Methods

A total of 1804 patients with AF had body mass index (BMI) measures from the Gulf survey of atrial fibrillation events (Gulf SAFE) registry were implied. A multivariable model was established to investigate the role of obesity on clinical outcomes, including stroke or systemic embolism, bleeding, admission for heart failure (HF) or AF, all-cause mortality and composite event.

Results

559 (31.0%) patients were identified as obesity (BMI over 30kg/m2). In multivariable analyses, obesity was associated with reduced risks of stroke/systematic embolism (hazard ratio [HR] 0.40, 95% confidence interval [CI] 0.18–0.89), major or clinical relevant bleeding (HR 0.44, 95% CI 0.26–0.74), HF admission (HR 0.61, 95% CI 0.41–0.90) and composite outcome (HR 0.65, 95% CI 0.50–0.84). Higher BMI was associated with lower risks of stroke/systemic embolism, bleeding, admission for HF, all-cause mortality, and composite outcomes as were demonstrated by accumulated incidence of events and restricted cubic splines.

Conclusion

Among patients with AF, higher BMI was associated with a more favorable prognosis.

The hazard ratio for BMI and outcomes

Funding Acknowledgement

Type of funding source: None

Symptom status, clinical subtypes and prognosis in Middle East patients with atrial fibrillation: a report from the Gulf-SAFE registry

Background

Atrial fibrillation (AF) is often asymptomatic. The prognosis of asymptomatic AF is similar or worse than symptomatic AF, but there are no such data from Middle East.

Method

The Gulf survey of AF events (Gulf SAFE) registry is a multi-center prospective survey of AF patients from six countries (23 centers) in the Gulf Region (n=2043). We investigated the prognostic outcomes of asymptomatic AF, in relation to clinical subtypes.

Result

541 (26.5%) AF patients were asymptomatic; they tended to be older, with higher prevalence of hypertension, heart failure (HF), diabetes, stroke, renal dysfunction, and higher CHADS2, CHA2DS2-VASc, and HAS-BLED scores (all p&lt;0.05). After multivariable adjustment, asymptomatic AF was associated with higher risks of stroke/systematic embolism (SE) (odds ratio [OR] 2.18, 95% confidence interval [CI] 1.10–4.34), all cause-mortality (OR 2.85 [1.90–4.28]) and the composite outcome of stroke/SE, bleeding and all-cause mortality (OR 1.74 [1.26–2.41]).

Asymptomatic AF was associated with fewer admissions for AF (OR 0.53 [0.32–0.83]) and HF (OR 0.58 [0.38–0.86]).

The increased risk of stroke/SE in asymptomatic AF was associated with paroxysmal AF (Figure 1; P interaction=0.028).

Conclusion

In this large Middle East cohort, asymptomatic AF was common, less likely hospitalized but associated with unfavorable prognosis. When AF was asymptomatic, the paroxysmal subtype had a greater association with stroke/SE.

Adjusted odds ratio of clinical outcomes

Funding Acknowledgement

Type of funding source: None

Effects of medium chain fatty acids as a mitigation or prevention strategy against porcine epidemic diarrhea virus in swine feed

Feed has been shown to be a vector for viral transmission. Four experiments were conducted to: 1) determine if medium chain fatty acids (MCFA) are effective mitigants when applied to feed both pre- and post-porcine epidemic diarrhea virus (PEDV) inoculation measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR), 2) evaluate varying levels and combinations of MCFA measured by qRT-PCR, and 3) evaluate selected treatments in bioassay to determine infectivity. In exp. 1, treatments were arranged in a 2 × 2 + 1 factorial with main effects of treatment (0.3% commercial formaldehyde [CF] product, Sal CURB [Kemin Industries, Inc.; Des Moines, IA], or 1% MCFA blend (Blend) of 1:1:1 C6:C8:C10 [PMI, Arden Hills, MN]) and timing of application (pre- or post-inoculation with PEDV) plus a positive control (PC; feed inoculated with PEDV and no treatment). All combinations of treatment and timing decreased detectable PEDV compared with the PC (P < 0.05). Pre-inoculation treatment elicited decreased magnitude of PEDV detection (cycle threshold value) compared with post-inoculation (P = 0.009). Magnitude of PEDV detection was decreased for CF compared with Blend (P < 0.0001). In exp. 2, pre-inoculation treatments consisted of: 1) PC, 2) 0.3% CF, 3 to 5) 0.125% to 0.33% C6:0, 6 to 8) 0.125% to 0.33% C8:0, 9 to 11) 0.125% to 0.33% C10:0, and 12 to 15) 0.125% to 0.66% C5:0. Treating feed with 0.33% C8:0 resulted in decreased (P < 0.05) PEDV detection compared with all other treatments. Increasing concentration of each individual MCFA decreased PEDV detectability (P < 0.042). In exp. 3, pre-inoculation treatments consisted of: 1) PC, 2) 0.3% CF, 3 to 7) 0.25% to 1% Blend, 8 to 10) 0.125% to 0.33% C6:0 + C8:0, 11 to 13) 0.125% to 0.33% C6:0 + C10:0, and 14 to 16) 0.125% to 0.33% C8:0 + C10:0. Treating feed with CF, 0.5% Blend, 0.75% Blend, 1% Blend, all levels of C6:0+C8:0, 0.25% C6:0 + 0.25% C10:0, 0.33% C6:0 + 0.33% C10:0, 0.25% C8:0 + 0.25% C10:0, or 0.33% C8:0 + 0.33% C10:0 elicited decreased detection of PEDV compared with PC (P < 0.05). Increasing concentration of each MCFA combination decreased PEDV detectability (linear, P < 0.012). In exp. 4, feed was treated pre-inoculation with: 1) no treatment (PC), 2) 0.3% CF, 3) 0.5% Blend, or 4) 0.3% C8:0 and analyzed via qRT-PCR and bioassay. Adding 0.5% Blend or 0.3% C8:0 resulted in decreased PEDV compared with PC and only PC resulted in a positive bioassay. Therefore, MCFA can decrease detection of PEDV in feed. Further, inclusion of lower levels of MCFA than previously evaluated are effective against PEDV.

Development of a differential multiplex real-time PCR assay for porcine circovirus type 2 (PCV2) genotypes PCV2a, PCV2b and PCV2d

•

A multiplex real-time PCR (mqPCR) is developed for PCV2a, 2b, and 2d differentiations.

•

Sequencing of 74 strains confirmed genotyping results generated by the mqPCR.

•

The mqPCR did not detect any non-target swine pathogens included in this study.

•

This genotyping assay is recommended following a general PCV2 diagnostic testing.

A multiplex quantitative real-time polymerase chain reaction (mqPCR) assay was developed and validated for detection and differentiation of porcine circovirus type 2 (PCV2) genotypes, PCV2a, PCV2b and PCV2d. Single nucleotide polymorphism in primers or probes was deployed for different genotype detections, while conserved sequence in the 3' end of a primer and in the middle of a probe was used for the targeted genotype. In silico analysis of 2601 PCV2 ORF2 sequences showed that the predicted strain coverage of the assay was 93.4 % (409/438) for PCV2a, 95.1 % (1161/1221) for PCV2b and 93.6 % (882/942) for PCV2d strains. The PCR amplification efficiencies were 94.5 %, 100.2 %, and 99.2 % for PCV2a, PCV2b and PCV2d, respectively, with correlation coefficients >0.995 for all genotypes. The limits of detection (LOD) were 1.58 × 10⁻⁴ TCID50/mL for PCV2a, 5.62 × 10⁻⁴ TCID50/mL for PCV2b, and 3.16 × 10⁻³ TCID50/mL for PCV2d. Sanger sequencing of 74 randomly selected PCV2 positive clinical samples confirmed the genotypes of strains identified by the mqPCR. Validation with clinical samples co-positive for target and non-target pathogens demonstrated that the mqPCR assay specifically detected targeted viruses without cross reacting to each other or to other common porcine viruses.

Long noncoding RNA LINC00473 indicates a poor prognosis of breast cancer and accelerates tumor carcinogenesis by competing endogenous sponging miR-497

OBJECTIVE

Long noncoding RNA LINC00473 (LINC00473) has been reported to be involved in the progression of several tumors. Our present study was conducted to study the potential roles and mechanism of long noncoding RNA LINC00473 (LINC00473) on cells proliferation, migration, invasion, and apoptosis of breast cancer (BC).

PATIENTS AND METHODS

RT-PCR was applied for the analysis of LINC00473 in BC cell lines and tissues samples. The correlations between the LINC00473 levels and clinicopathological parameters were investigated. Kaplan-Meier methods and Cox proportional hazards regression models were explored to reveal potential associations of LINC00473 levels with overall survival of BC patients. The effect of LINC00473 on tumor behavior was evaluated by colony formation, Cell Counting Kit-8, EdU assays, flow-cytometric analysis, wound healing assays and transwell assays. Interactions between LINC00473 and miR-497 were determined using a luciferase reporter assay and RT-PCR assays.

RESULTS

Upregulation of the expression of LINC00473 was found in BC samples and cell lines, in comparison with non-tumor breast tissues and human breast epithelial cells. High expression of LINC00473 was correlated with lymph node metastasis, clinical stage, and poorer outcome in BC patients. Multivariate logistic regression assays further showed LINC00473 as an independent prognostic factor in BC. Lost-of-function assays revealed that knockdown of LINC00473 resulted in the suppression of tumor cell proliferation, promotion of cells apoptosis, inhibition of cells metastasis. Bioinformatics analysis and luciferase reporter assays revealed LINC00473 bonds to miR-497. Further RT-PCR revealed that knockdown of LINC00473 suppressed the expressions of miR-497 in BC cells.

CONCLUSIONS

Our data revealed that LINC00473 acted as a tumor promoter in BC and LINC00473/miR-497 axis may be a novel therapeutic strategy for this tumor.

Development of a bead-based assay for detection and differentiation of field strains and four vaccine strains of type 2 porcine reproductive and respiratory syndrome virus (PRRSV-2) in the USA

Porcine reproductive and respiratory syndrome (PRRS) remains one of the most economically devastating diseases in swine population in the United States of America. Due to high mutation rate of the PRRS virus (PRRSV) genome, it is difficult to develop an accurate diagnostic assay with high strain coverage. Differentiation of field strains from the four vaccines that have been used in the USA, namely Ingelvac PRRS MLV, Ingelvac ATP, Fostera PRRS and Prime Pac PRRS, adds an additional challenge. It is difficult to use current real-time PCR systems to detect and differentiate the field strains from the vaccine strains. Luminex xTAG technology allows us to detect more molecular targets in a single reaction with a cost similar to a single real-time PCR reaction. By analysing all available 678 type 2 PRRSV (PRRSV-2) complete genome sequences, including the 4 vaccine strains, two pairs of detection primers were designed targeting the conserved regions of ORF4-ORF7, with strain coverage of 98.8% (670/678) based on in silico analysis. The virus strains sharing ≥98% identity of the complete genomes with the vaccine strains were considered vaccine or vaccine-like strains. One pair of primers for each vaccine strain were designed targeting the nsp2 region. In silico analysis showed the assay matched 94.7% (54/57) of Ingelvac PRRS^® MLV (MLV) strain and the MLV-like strains, and 100% of the other three vaccine strains. Analytical sensitivity of the Luminex assay was one to two logs lower than that of the reverse transcription real-time PCR assay. Evaluated with 417 PRRSV-2 positive clinical samples, 95% were detected by the Luminex assay. Compared to ORF5 sequencing results, the Luminex assay detected 92.4% (73/79) of MLV strains, 78.3% (18/23) of Fostera strains and 50% (2/4) of ATP strains. None of the 472 samples were the Prime Pac strain tested by either ORF5 sequencing or the Luminex assay.

Polymerase Chain Reaction-Based Prevalence of Serogroups of Escherichia coli Known to Carry Shiga Toxin Genes in Feces of Finisher Pigs

Shiga toxin-producing Escherichia coli (STEC) are major foodborne pathogens and seven serogroups, O26, O45, O103, O111, O121, O145, and O157, that account for the majority of the STEC-associated illness in humans. Similar to cattle, swine also harbor STEC and shed them in the feces and can be a source of human STEC infections. Information on the prevalence of STEC in swine feces is limited. Therefore, our objective was to utilize polymerase chain reaction (PCR) assays to determine prevalence of major virulence genes and serogroups of STEC. Fecal samples (n = 598), collected from finisher pigs within 3 weeks before marketing in 10 pig flows located in 8 states, were included in the study. Samples enriched in E. coli broth were subjected to a real-time PCR assay targeting three virulence genes, Shiga toxin 1 (stx1), Shiga toxin 2 (stx2), and intimin (eae), which encode for Shiga toxins 1 and 2, and intimin, respectively. A novel PCR assay was designed and validated to detect serogroups, O8, O20, O59, O86, O91, O100, O120, and O174, previously reported to be commonly present in swine feces. In addition, enriched fecal samples positive for Shiga toxin genes were subjected to a multiplex PCR assay targeting O26, O45, O103, O104, O111, O121, O145, and O157 serogroups implicated in human clinical infections. Of the 598 fecal samples tested by real-time PCR, 25.9%, 65.1%, and 67% were positive for stx1, stx2, and eae, respectively. The novel eight-plex PCR assay indicated the predominant prevalence of O8 (88.6%), O86 (35.5%), O174 (24.1%), O100 (20.2%), and O91 (15.6%) serogroups. Among the seven serogroups relevant to human infections, three serogroups, O121 (17.6%), O157 (14%), and O26 (11%) were predominant. PCR-based detection indicated high prevalence of Shiga toxin genes and serogroups that are known to carry Shiga toxin genes, including serogroups commonly prevalent in cattle feces and implicated in human infections and in edema disease in swine.

Multiplex PCR Assays for the Detection of One Hundred and Thirty Seven Serogroups of Shiga Toxin-Producing Escherichia coli Associated With Cattle

Escherichia coli carrying prophage with genes that encode for Shiga toxins are categorized as Shiga toxin-producing E. coli (STEC) pathotype. Illnesses caused by STEC in humans, which are often foodborne, range from mild to bloody diarrhea with life-threatening complications of renal failure and hemolytic uremic syndrome and even death, particularly in children. As many as 158 of the total 187 serogroups of E. coli are known to carry Shiga toxin genes, which makes STEC a major pathotype of E. coli. Seven STEC serogroups, called top-7, which include O26, O45, O103, O111, O121, O145, and O157, are responsible for the majority of the STEC-associated human illnesses. The STEC serogroups, other than the top-7, called “non-top-7” have also been associated with human illnesses, more often as sporadic infections. Ruminants, particularly cattle, are principal reservoirs of STEC and harbor the organisms in the hindgut and shed in the feces, which serves as a major source of food and water contaminations. A number of studies have reported on the fecal prevalence of top-7 STEC in cattle feces. However, there is paucity of data on the prevalence of non-top-7 STEC serogroups in cattle feces, generally because of lack of validated detection methods. The objective of our study was to develop and validate 14 sets of multiplex PCR (mPCR) assays targeting serogroup-specific genes to detect 137 non-top-7 STEC serogroups previously reported to be present in cattle feces. Each assay included 7–12 serogroups and primers were designed to amplify the target genes with distinct amplicon sizes for each serogroup that can be readily identified within each assay. The assays were validated with 460 strains of known serogroups. The multiplex PCR assays designed in our study can be readily adapted by most laboratories for rapid identification of strains belonging to the non-top-7 STEC serogroups associated with cattle.

Influence of an InGaN superlattice pre-layer on the performance of semi-polar (11-22) green LEDs grown on silicon

It is well-known that it is crucial to insert either a single InGaN underlayer or an InGaN superlattice (SLS) structure (both with low InN content) as a pre-layer prior to the growth of InGaN/GaN multiple quantum wells (MQWs) served as an active region for a light-emitting diode (LED). So far, this growth scheme has achieved a great success in the growth of III-nitride LEDs on c-plane substrates, but has not yet been applied in the growth of any other orientated III-nitride LEDs. In this paper, we have applied this growth scheme in the growth of semi-polar (11–22) green LEDs, and have investigated the impact of the SLS pre-layer on the optical performance of semi-polar (11–22) green LEDs grown on patterned (113) silicon substrates. Our results demonstrate that the semi-polar LEDs with the SLS pre-layer exhibit an improvement in both internal quantum efficiency and light output, which is similar to their c-plane counterparts. However, the performance improvement is not so significant as in the c-plane case. This is because the SLS pre-layer also introduces extra misfit dislocations for the semi-polar, but not the c-plane case, which act as non-radiative recombination centres.