Transcriptome analysis of the synergistic mechanisms between two strains of potato virus Y in Solanum tuberosum L

Many viruses employ a process known as superinfection exclusion (SIE) to block subsequent entry or replication of the same or closely related viruses in the cells they occupy. SIE is also referred to as Cross-protection refers to the situation where a host plant infected by a mild strain of a virus or viroid gains immunity against a more severe strain closely related to the initial infectant. The mechanisms underlying cross-protection are not fully understood. In this study, we performed a comparative transcriptomic analysis of potato (Solanum tuberosum L.) leaves. The strains PVYN-Wi-HLJ-BDH-2 and PVYNTN-NW-INM-W-369-12 are henceforth designated as BDH and 369, respectively. In total, 806 differentially expressed genes (DEGs) were detected between the Control and JZ (preinfected with BDH and challenge with 369) treatment. Gene Ontology (GO) analysis showed that the response to external biological stimulation, signal transduction, kinase, immunity, redox pathways were significantly enriched. Among these pathways, we identified numerous differentially expressed metabolites related to virus infection. Moreover, our data also identified a small set of genes that likely play important roles in the establishment of cross-protection. Specifically, we observed significant differential expression of the A1-II gamma-like gene, elongation factor 1-alpha-like gene, and subtilisin-like protease StSBT1.7 gene, with StSBT1.7 being the most significant in our transcriptome data. These genes can stimulate the expression of defense plant genes, induce plant chemical defense, and participate in the induction of trauma and pathogenic bacteria. Our findings provided insights into the mechanisms underlying the ability of mild viruses to protect host plants against subsequent closely related virus infection in Solanum tuberosum L.

[Clinicopathological features and HER2 expression of metaplastic squamous cell carcinoma of the breast]

Objective: To investigate the clinicopathological features and HER2 expression of metaplastic squamous cell carcinoma (MSCC) of the breast. Methods: A total of 47 MSCC cases diagnosed in the Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China from January 2010 to December 2021 were reviewed. The clinical information (including the follow-up data of HER2 positive patients) and pathological features were collected and analyzed. Results: All of the patients were female. Among the 47 cases, 25 were pure squamous cell carcinoma (PSCC) and 22 were mixed metaplastic carcinoma with squamous cell component (MMSC). The median age of the patients was 54 years (range, 29-84 years). The maximum diameter of the mass ranged from 0.8 to 10.0 cm, with a mean value of 3.3 cm, 85.7% (24/28) of the cases were smaller than 5 cm, and only 4 cases were larger than or equal to 5 cm. 89.5% of the MMSC presented with a solid mass. Cystic changes were more commonly found in the PSCC group (50%, P<0.05) than the MMSC group. 36.7% (11/30) of the patients had lymph node metastasis at the time of diagnosis. The squamous cell carcinoma component in all cases showed diffuse or patchy expression of p63, p40 and CK5/6. 55.3% (26/47) of the cases showed triple-negative phenotype. Among the 7 HER2-positive patients, 6 were MMSC group, which had a significantly higher rate of HER2-positivity than that in the PSCC group (1 case). In 1 MMSC case, immunohistochemistry showed HER2 2+in the invasive ductal carcinoma component and HER2 negativity (0) in the squamous cell carcinoma component, but HER2 FISH was negative in invasive ductal carcinoma and positive in squamous cell carcinoma component. Six HER2-positive MSCC patients received anti-HER2-targeted therapy, including two patients who received neoadjuvant chemotherapy combined with anti-HER2-targeted therapy before surgery. One patient achieved pathological complete remission, while the other achieved partial remission (the residual tumors were squamous cell carcinoma components). After 9-26 months of follow-up, four patients had no disease progression, two patients developed pulmonary metastases, and one patient showed local recurrence. Conclusions: MSCC is a group of heterogeneous diseases. PSCC and MMSC may be two different entities. Most of the MSCC are triple-negative and HER2 positivity is more commonly seen in MMSC with invasive ductal carcinoma component. Some HER2-positive MSCC patients can achieve complete remission or long-term progression-free survival after receiving anti-HER2 targeted therapy, but the squamous cell carcinoma component may be less sensitive to targeted therapy than the invasive ductal carcinoma component.

Anaerobiosis modulation of two phytoglobins in barley (Hordeum vulgare L.), and their regulation by gibberellin and abscisic acid in aleurone cells

The transcript levels of the phytoglobin (Pgb) genes Pgb1 and Pgb3, and the protein content of Pgb1 were responsive to anaerobiosis in several tissues of barley (Hordeum vulgare L.). Oxygen deficiency induced the level of both Pgb transcripts and protein in aleurone layers and coleoptiles, as well as up-regulated both Pgb1 and Pgb3 in leaves, apexes and more strongly in roots of barley seedlings. In O₂-depleted aleurone cells the induction of the Pgb transcript-protein pair was reversed by re-supplying O₂. Based on this observation, it is suggested that Pgb1 and Pgb3 are inducible in all tissues. In aleurone cells, gibberellic acid (GA) induced Pgb1 and Pgb3 together with α-amylase, whereas abscisic acid (ABA) eliminated the GA stimulating effects on both α-amylase and Pgb1 and Pgb3 expression. While GA had no effects on alcohol dehydrogenase (Adh1, Adh2 and Adh3) transcripts, ABA induced all three Adh genes. It is concluded that Pgb and α-amylase in seeds are regulated reciprocally with the ethanolic fermentation pathway, and that Pgb induction is mediated by GA. Nitric oxide turnover and scavenging mediated by Pgb represents an important alternative to fermentation under anoxia.

Potato Virus Y Strain N-Wi Offers Cross-Protection in Potato Against Strain NTN-NW by Superior Competition

Potato virus Y (PVY) is one of the most economically important pathogens of potato. PVY exhibits different phenotypes in dissimilar potato cultivars. Previously, we observed that two recombinant isolates, PVY^N-Wi-HLJ-BDH-2 (BDH) and PVY^NTN-NW(SYR-II)-INM-W-369-12 (369), exhibited different virulence levels in potato cultivar Kexin 13 despite high genome sequence identity. Indeed, 369 induced severe necrosis and plant death in severe cases in Kexin 13 and severe mosaic in cultivar Yanshu 8, whereas BDH caused mainly mosaic symptoms on the plants of both cultivars. We hypothesized that preinfection of plants with BDH could cross-protect them from 369 infection, and not vice versa. Challenge inoculation, either by mechanical wounding or through grafting, with 369 on plants that were preinfected with BDH did not augment the symptom expression in both cultivars. Reverse transcription quantitative PCR analysis showed that, after challenge inoculation with 369, the titer of the isolate on BDH-preinfected plants remained at a low level (about 3 × 10⁴ copy/µl) during the tested time course (0 h to 30 days). In contrast, in plants that were preinoculated with buffer (mock) and challenge inoculated with 369, the titer of 369 increased continuously until reaching its highest level of about 2 × 10⁷ (Yanshu 8) and about 4 × 10⁸ (Kexin 13) during the time course. Surprisingly, in plants that were preinfected with 369 and challenge inoculated with BDH, the accumulation of BDH reached nearly the same level as that in plants that were preinoculated with buffer and challenge inoculated with BDH. Taken together, these results suggest that PVY^N-Wi mediated cross-protection against PVY^NTN-NW(SYR-II) by superior competition and better fitness.

[Investigation on occupational hazard factors in teaching and research places of a university]

Objective: To investigate and monitor the occupational hazards in the Teaching and Research Laboratory (hereinafter referred to as the place) of a university, so as to provide basis for the occupational health work in the university. Methods: November 2014, 46 places in a university were selected by stratified random sampling, and the occupational health risk factors were investigated. Results: Indoor temperature, humidity, sulfur dioxide, nitrogen dioxide, carbon monoxide and carbon dioxide were detected in 21 sites, xylene and hydrofluoric acid were detected in 6 sites, and colony count was detected in 18 sites, the power frequency electric field intensity was measured in 23 places, and the x-ray radiation dose was measured in 4 places. Noise was measured at 21 sites, with 7 sites exceeding the standards accounting for 33.3% (7/21) ; 21 sites were detected for illumination and 10 sites for nonconformity accounting for 47.6% (10/21) ; 10 sites for Microwave Radiation and 3 sites exceeding the standards accounting for 30% (3/10) ; and 25 sites were detected for outdoor air volume and air velocity, the percentage of unqualified was 72% (18/25) in 18 sites, among which the wind velocity was statistically significant in teaching, research and experimental sites (P=0.010) . Conclusion: The occupational hazards in the teaching and research places of a university should be paid attention to, and the engineering protection and personal protection should be strengthened in the experiment.

Global Screening and Functional Identification of Major HSPs Involved in PVY Infection in Potato

HSP40 (also known as DnaJ), HSP70, and HSP90 are major heat shock protein (HSP) families that play critical roles in plant growth and development and stress adaption. Recently, several members of the three HSP families were reported to be widely involved in the plant host-virus interactions. However, their global expression profiles and core members recruited by viruses are largely unknown. In this study, a total of 89 StDnaJs were identified from a genome-wide survey, and their classification, phylogenetic relationships, chromosomal locations, and gene duplication events were further analyzed. Together with 20 StHSP70s and 7 StHSP90s previously identified in the potato genome, the global expression patterns of the members in 3 HSP families were investigated in 2 potato cultivars during Potato virus Y (PVY) infection using RNA-seq data. Of them, 16 genes (including 8 StDnaJs, 6 StHSP70s, and 2 StHSP90s) were significantly up- or downregulated. Further analysis using qRT-PCR demonstrated that 7 of the 16 genes (StDnaJ06, StDnaJ17, StDnaJ21, StDnaJ63, StHSP70-6, StHSP70-19, and StHSP90.5) were remarkably upregulated in the potato cultivar 'Eshu 3' after PVY infection, implying their potential roles in the potato-PVY compatible interaction. Subsequent virus-induced gene silencing (VIGS) assays showed that silencing of the homologous genes of StDnaJ17, StDnaJ21, StHSP70-6, and StHSP90.5 in Nicotiana. benthamiana plants dramatically reduced the accumulation of PVY, which indicated the four genes may function as susceptibility factors in PVY infection. This study provides candidate genes for exploring the mechanism of potato-PVY compatible interaction and benefits breeding work aiming to produce new cultivars with the ability to grow healthily under PVY infection.

Comparison of Mineral Oil, Insecticidal, and Biopesticide Spraying Regimes for Reducing Spread of Three Potato virus Y Strains in Potato Crops

In-field management of Potato virus Y (PVY) faces challenges caused by the changing availability and environmental acceptability of chemical agents to control aphid vectors of the virus and by proliferation of PVY strains with different symptoms and rates of spread. From 2018 to 2020, foliar spray treatments were compared in field experiments in New Brunswick, Canada, to measure effectiveness at reducing spread of PVY^O, PVY^N:O, and PVY^NTN strains. Mineral oil, insecticide, combined oil and insecticide spray, and a biopesticide (i.e., LifeGard WG) were compared. Insecticide-only and mineral oil-only treatments were not effective, but several combined oil and insecticide treatments and biopesticide treatments significantly reduced PVY spread. The biopesticide was proportionately more effective with recombinant PVY^N:O and PVY^NTN strains, possibly by exciting the plant's hypersensitive resistance response, caused naturally only in cultivar 'Goldrush' by PVY^O. Pesticide residue analysis showed that mineral oil increased the retention of pyrethroid insecticide in the potato foliage longer than with insecticide applied alone, which may explain the beneficial synergistic effect of combined sprays for reducing PVY spread. Tuber yields were generally unchanged in chemical insecticide treatments but were slightly lower in biopesticide treatment. The cost per PVY treatment was competitive across all effective treatments, including biopesticide; however, there was some revenue loss from lower yield with the biopesticide. This biopesticide is certified organic, however, and thus a small premium on the price for organic production could offset this yield deficit.

Susceptibility factor StEXA1 interacts with StnCBP to facilitate potato virus Y accumulation through the stress granule-dependent RNA regulatory pathway in potato

Plant viruses recruit multiple host factors for translation, replication, and movement in the infection process. The loss-of-function mutation of the susceptibility genes will lead to the loss of susceptibility to viruses, which is referred to as 'recessive resistance'. Essential for potexvirus Accumulation 1 (EXA1) has been identified as a susceptibility gene required for potexvirus, lolavirus, and bacterial and oomycete pathogens. In this study, EXA1 knockdown in potato (StEXA1) was found to confer novel resistance to potato virus Y (PVY, potyvirus) in a strain-specific manner. It significantly compromised PVY^O accumulation but not PVY^N:O and PVY^NTN. Further analysis revealed that StEXA1 is associated with the HC-Pro of PVY through a member of eIF4Es (StnCBP). HC-Pro^O and HC-Pro^N, two HC-Pro proteins from PVY^O and PVY^N, exhibited strong and weak interactions with StnCBP, respectively, due to their different spatial conformation. Moreover, the accumulation of PVY^O was mainly dependent on the stress granules (SGs) induced by StEXA1 and StnCBP, whereas PVY^N:O and PVY^NTN could induce SGs by HC-Pro^N independently through an unknown mechanism. These results could explain why StEXA1 or StnCBP knockdown conferred resistance to PVY^O but not to PVY^N:O and PVY^NTN. In summary, our results for the first time demonstrate that EXA1 can act as a susceptibility gene for PVY infection. Finally, a hypothetical model was proposed for understanding the mechanism by which StEXA1 interacts with StnCBP to facilitate PVY accumulation in potato through the SG-dependent RNA regulatory pathway.

Nociceptor Neurons Magnify Host Responses to Aggravate Periodontitis

Periodontitis is a highly prevalent chronic inflammatory disease that progressively destroys the structures supporting teeth, leading to tooth loss. Periodontal tissue is innervated by abundant pain-sensing primary afferents expressing neuropeptides and transient receptor potential vanilloid 1 (TRPV1). However, the roles of nociceptive nerves in periodontitis and bone destruction are controversial. The placement of ligature around the maxillary second molar or the oral inoculation of pathogenic bacteria induced alveolar bone destruction in mice. Chemical ablation of nociceptive neurons in the trigeminal ganglia achieved by intraganglionic injection of resiniferatoxin decreased bone loss in mouse models of experimental periodontitis. Consistently, ablation of nociceptive neurons decreased the number of osteoclasts in alveolar bone under periodontitis. The roles of nociceptors were also determined by the functional inhibition of TRPV1-expressing trigeminal afferents using an inhibitory designer receptor exclusively activated by designer drugs (DREADD) receptor. Noninvasive chemogenetic functional silencing of TRPV1-expressing trigeminal afferents not only decreased induction but also reduced the progression of bone loss in periodontitis. The infiltration of leukocytes and neutrophils to the periodontium increased at the site of ligature, which was accompanied by increased amount of proinflammatory cytokines, such as receptor activator of nuclear factor κΒ ligand, tumor necrosis factor, and interleukin 1β. The extents of increase in immune cell infiltration and cytokines were significantly lower in mice with nociceptor ablation. In contrast, the ablation of nociceptors did not alter the periodontal microbiome under the conditions of control and periodontitis. Altogether, these results indicate that TRPV1-expressing afferents increase bone destruction in periodontitis by promoting hyperactive host responses in the periodontium. We suggest that specific targeting of neuroimmune and neuroskeletal regulation can offer promising therapeutic targets for periodontitis supplementing conventional treatments.

Extreme Resistance to Potato Virus A in Potato Cultivar Barbara is Independently Mediated by Ra and Rysto

Potato virus A (PVA) and potato virus Y (PVY) are two members of genus Potyvirus infecting potato crops worldwide. Host resistance offers an economical and effective means for the control or management of these viruses. In this study, 20 potato clones were screened for their resistance against PVA and PVY by mechanical or graft inoculation assay, and were explored for the relationship between extreme resistance genes Ra and Ry by the detection of molecular markers linked to Ry_adg, Ry_sto, and Ry_chc. Six clones, including Barbara, Jizhangshu 8, Longshu 7, Longshu 8, M6, and Solara, were found to be extremely resistant to both PVA and PVY; three clones (AC142, Eshu 3, and Shepody) were deemed to be extremely resistant to PVA but susceptible to PVY. To further reveal the inheritance of the extreme resistance (ER) against PVA, a tetraploid F₁ population of Barbara × F58050 (susceptible to both PVY and PVA) and a tetraploid BC₁ population of BF145 (a PVA-resistant but PVY-susceptible progeny of Barbara × F58050) × F58050 were obtained. Phenotyping of the F₁ and BC₁ populations by graft inoculation with PVA showed segregation ratios of 3:1 and 1:1 (resistant:susceptible), respectively. These results suggest that two independent loci control ER against PVA in Barbara: one confers ER to both PVA and PVY and the other confers ER to PVA only. The deduced genotype of Barbara is RyryryryRararara.

Development of High-Resolution DNA Melting Analysis for Simultaneous Detection of Potato Mop-Top Virus and Its Vector, Spongospora subterranea, in Soil

In this study, a set of duplex reverse transcription PCR (RT-PCR)-mediated high-resolution DNA melting (HRM) analyses for simultaneous detection of potato mop-virus (PMTV) and its protist vector, Spongospora subterranea f. sp. subterranea (Sss), was developed. The infestation of soil by PMTV was detected with a tobacco-based baiting system. Total RNA extracted from the soil led to successful RT-PCR gel electrophoresis detection of both PMTV and Sss. To facilitate more efficient detection, newly designed primer pairs for PMTV RNA species (i.e., RNA-Rep, RNA-CP, and RNA-TGB) were analyzed together with the existing Sss primers via real-time RT-PCR. The resulting amplicons exhibited melting profiles that could be readily differentiated. Under duplex RT-PCR format, all PMTV and Sss primer combinations led to successful detection of respective PMTV RNA species and Sss in the samples by HRM analyses. When the duplex HRM assay was applied to soil samples collected from six fields at four different sites in New Brunswick, Canada, positive detection of PMTV or Sss was found in 63 to 100% samples collected from fields in which PMTV-infected tubers had been observed. In contrast, the samples from fields where neither PMTV- nor Sss-infected tubers had been observed resulted in negative detection by the assay. Bait tobacco bioassay for PMTV and Sss produced similar results. Of the soil samples collected from PMTV-infested fields, 63 to 83% and 100% led to PMTV and Sss infections in the bait tobacco plants, respectively, whereas no PMTV- or Sss-infected plants were obtained from soil samples collected from PMTV- and Sss-free fields.

Totally endoscopic sublay (TES) repair for lateral abdominal wall hernias: technique and first results

BACKGROUND

The optimal surgical treatment for lateral hernias of the abdominal wall remains unclear. The presented prospective study assesses for the first time in detail the clinical value of a totally endoscopic sublay (TES) technique for the repair of these hernias.

METHODS

Twenty-four consecutive patients with a lateral abdominal wall hernia underwent TES repair. This technique is naturally combined with a transversus abdominis release maneuver to create a sufficient retromuscular/preperitoneal space that can accommodate, if necessary, a giant prosthetic mesh.

RESULTS

The operations were successful in all but one patient who required open conversion because of dense intestinal adhesion. The mean defect width was 6.7 ± 3.9 cm. The mean defect area was 78.0 ± 102.4 cm² (range 4-500 cm²). The mean mesh size used was 330.2 ± 165.4 cm² (range 108-900 cm²). The mean operative time was 170.2 ± 73.8 min (range, 60-360 min). The mean visual analog scale score for pain at rest on the first day was 2.5 (range 1-4). The average postoperative stay was 3.4 days (range 2-7 days). No serious complications (Dindo-Clavien Grade 2-4) were seen within a mean follow-up period of 13.3 months.

CONCLUSIONS

A totally endoscopic technique (TES) for the treatment of lateral hernias is described. The technique revealed to be reliable, safe and cost-effective. The first results are promising, but larger studies with longer follow-up periods are recommended to determine the real clinical value.

Retroperitoneal totally endoscopic prosthetic repair of primary lumbar hernia

PURPOSE

A primary lumbar hernia is a rare entity that requires surgical management, but the preferred technique has not been established. We herein describe a standardized and reproducible retroperitoneal totally endoscopic prosthetic (TEP) repair technique for primary lumbar hernias.

METHODS

Ten adult patients with primary lumbar hernias underwent retroperitoneal TEP repair from February 2019 to July 2020. A sufficient retroperitoneal space was established to accommodate a non-coated polypropylene mesh to reinforce the weakened flank area, and hernia content reduction and defect closure were then performed. The patients' clinical data were prospectively collected and analyzed.

RESULTS

Nine patients had a primary superior lumbar hernia and one patient had a primary diffuse lumbar hernia. All operations were successfully performed without serious intraoperative complications. The mean defect area was 6.4 ± 2.8 cm² (range 4-12 cm²), and the mean mesh area was 144.6 cm² (range 130-180 cm²). The average operative time (skin to skin) was 49.0 ± 5.7 min (range 40-60 min), and intraoperative bleeding was minimal. The mean visual analog pain scale score at rest on the first postoperative day was 2.2 (range 2-3). The average length of postoperative stay was 1.5 days (range 1-2 days). No serious postoperative complications occurred. No recurrence, chronic pain, or mesh infection occurred during a mean follow-up period of 7.5 months.

CONCLUSIONS

The retroperitoneal TEP repair for primary lumbar hernias is safe, efficient, and reproducible. Anti-adhesive coated meshes and fixation tackers are not required, making this a cost-effective procedure that is worthy of recommendation.

Quasi-oracle estimation of heterogeneous treatment effects

Flexible estimation of heterogeneous treatment effects lies at the heart of many statistical applications, such as personalized medicine and optimal resource allocation. In this article we develop a general class of two-step algorithms for heterogeneous treatment effect estimation in observational studies. First, we estimate marginal effects and treatment propensities to form an objective function that isolates the causal component of the signal. Then, we optimize this data-adaptive objective function. The proposed approach has several advantages over existing methods. From a practical perspective, our method is flexible and easy to use: in both steps, any loss-minimization method can be employed, such as penalized regression, deep neural networks, or boosting; moreover, these methods can be fine-tuned by cross-validation. Meanwhile, in the case of penalized kernel regression, we show that our method has a quasi-oracle property. Even when the pilot estimates for marginal effects and treatment propensities are not particularly accurate, we achieve the same error bounds as an oracle with prior knowledge of these two nuisance components. We implement variants of our approach based on penalized regression, kernel ridge regression, and boosting in a variety of simulation set-ups, and observe promising performance relative to existing baselines.

[Pathological changes of the spleen in ten patients with coronavirus disease 2019(COVID-19) by postmortem needle autopsy]

Objective: To study the pathological changes of the spleen in patients with COVID-19 and to analyze the relationship between the weakened immune system and splenic lesions. Methods: Postmortem needle autopsies from the spleen were carried out on 10 patients who died from COVID-19 in Wuhan. Routine hematoxylin and eosin (HE) staining was used to observe the pathological changes. The changes of lymphocytes were studied further with immunohistochemistry.RT-PCR was used to detect 2019-nCoV RNA in the spleen. In addition,the Epstein-Barr virus (EBV) was detected by in situ hybridization, and coronavirus particles were detected by transmission electron microscopy in 2 cases. Results: There were 7 males and 3 females, with an average age of 68.3 years.Of the 10 cases, 4 had cancer history and another 4 had other underlying diseases respectively.Cough, fever, malaise and dyspnea were the main clinical symptoms.The time from onset to death was 15-45 days.Ten cases patients had normal or slight increase in peripheral blood leukocyte count in the early stage of the disease, 6 cases had significant increase before death. Five patients' peripheral blood lymphocyte count decreased in the early stage of the disease, and 10 patients' peripheral blood lymphocyte count decreased significantly before the disease progressed or died. Seven cases were treated with corticosteroid (methylprednisolone ≤40 mg/d, not more than 5 days). Histopathological examination showed that the cell composition of the spleen decreased, white pulp atrophied at different levels, meanwhile lymphoid follicles decreased or absent;in addition, the ratio of red pulp to white pulp increased with varying degrees. In 7 cases, more neutrophil infiltration was found, and in 5 cases, scattered plasma cell infiltration was found. Macrophage proliferation and hemophagocytic phenomena in a few cells were found in a case. Meanwhile, necrosis and lymphocyte apoptosis were detected in 2 cases, small artery thrombosis and spleen infarction in 1 case, and fungal infection in 1 case. The results of immunohistochemistry showed that the T and B lymphocyte components of the spleen in all cases decreased in varying degrees. CD20(+) B cells were found to accumulate in the lymphoid sheath around the splenic artery in 8 cases. However, CD20 and CD21 immunostaining in 2 cases showed that the number of white pulp was almost normal, and splenic nodules were atrophic. CD3(+), CD4(+) and CD8(+)T cells were decreased. In 9 cases,CD68(+) macrophages were no significant changes in the distribution and quantity. While more CD68(+) cells were found in the medullary sinuses of 1 case (related to fungal infection). Few CD56(+) cells were found. EBV was negative by in situ hybridization. RT-PCR was used to detect the nucleic acid of 2019-nCoV. One of 10 cases was positive, 39 years old,who was the youngest patient in this group, and the other 9 cases were negative. Coronavirus particles were found in the cytoplasm of macrophage under electron microscope in 2 cases. Conclusions: The death of COVID-19 occurs mainly in the elderly, and some cases have no underlying diseases. Spleen may be one of the organs directly attacked by the virus in some patients who died from COVID-19. T and B lymphocyte in the spleen decrease in varying degrees, lymphoid follicles are atrophied, decreased or absent, and the number of NK cells do not change significantly. And the pathological changes of the spleen are not related to the use of low dose corticosteroid, which may be related to the direct attack of virus and the attack of immune system on its own tissues.

OP0246 MIR-214-3P PROTECTS AGAINST OSTEOARTHRITIS BY DIRECTLY TARGETING NF-ĸB PATHWAY

Background:

Osteoarthritis (OA) is a degenerative disease associated with changes in the articular cartilage and bone, severely affecting patients’ mobility and quality of life. Multiple factors including mechanical stress, metabolic alteration and inflammatory mediators are involved in the complex pathogenesis of OA[1]. Interventions targeting these pathogenic factors may contribute to the treatment of OA. MiRNAs are single strand non-coding small RNAs, which are regulated in chondrogenesis and OA[2,3]. Recent studies demonstrated that miRNAs are involved in the regulation of NF-κB signaling pathway by different mechanisms[4]. These interactions suggest that NF-κB related miRNAs may be used as potential biomarkers and drug therapeutic targets in clinical treatment of OA. However, the relationship between miR-214-3p and NF-κB pathway remains poorly understood in OA.

Objectives:

This study aimed to test the expression and biological function of miR-214-3p in OA, and explore its mechanism in osteoarthritic chondrocytes.

Methods:

Articular primary chondrocytes were isolated from human cartilage samples, which were acquired from patients with end-stage knee OA at the time of total knee replacement surgery (n = 27), according to protocols approved by the Ethic Committee of Zhujiang Hospital. Real time PCR (RT-PCR) and in situ hybridization (ISH) were used to detect the expression of miR-214-3p in OA and non-OA cartilage tissues. Interference of miR-214-3p was conducted using inhibitor, while overexpression of miR-214-3p was performed with mimics. Metabolism of extracellular matrix was detected by RT-PCR, western blotting and immunofluorescence in vitro. Flow cytometry were conducted to determine cell apoptosis. A luciferase reporter assay, was used to evaluate the interaction between miR-214-3p and its downstream target. Human chondrocytes were cotransfected with miR-214-3p and the IKBKB-overexpressing plasmid to confirm the interaction between miR-214-3p and NF-ĸB pathway. For in vivo studies, experimental OA was induced in 12-week-old male C57BL/6J mice by destabilization of the medial meniscus (DMM) surgery with miR-214-3p agomir intra-articular (IA) injection (once weekly for 12 days) or by IA injection (once weekly for 12 days) of miR-214-3p antiagomir. Mice were sacrificed 10 weeks after the first IA injection, and subjected to histological analyses.

Results:

MiR-214-3p was significantly reduced in human OA cartilage. The decreased expression of miR-214-3p in the OA cartilage tissues was directly associated with excessive apoptosis and imbalance between anabolic and catabolic factors of ECM. Mechanistically, we determined that miR-214-3p directly targeted IKBKB/IKK-b and thereby suppressed the activation of NF-ĸB pathway. IKBKB overexpression attenuated the inhibitory effect of miR-214-3p on NF-ĸB pathway. Furthermore, inhibition of miR-214-3p in mice joints triggered spontaneous cartilage loss and OA development, while IA injection of miRNA-214-3p agomir alleviated OA in the DMM mouse model.

Conclusion:

Our results reveal an important role of miR-214-3p in OA progression. MiR-214-3p was down-regulated while IKBKB was upregulated in OA. MiR-214-3p inhibits the NF-kB signaling pathway and suppresses the progression of OA through targeting IKBKB. Thus, miR-214-3p maybe a therapeutic target for OA.

References:

[1]Glyn-Jones S, Palmer AJR, Agricola R, Price AJ, Vincent TL, Weinans H, Carr AJ:Osteoarthritis.The Lancet2015,386(9991):376-387.

[2]Nugent M:MicroRNAs: exploring new horizons in osteoarthritis.Osteoarthritis and cartilage2016,24(4):573-580.

[3]Vicente R, Noel D, Pers YM, Apparailly F, Jorgensen C:Deregulation and therapeutic potential of microRNAs in arthritic diseases.Nature reviews Rheumatology2016,12(4):211-220.

[4]Xu B, Li YY, Ma J, Pei FX:Roles of microRNA and signaling pathway in osteoarthritis pathogenesis.Journal of Zhejiang University Science B2016,17(3):200-208.

Disclosure of Interests:

None declared

Single-site laparoscopic percutaneous extraperitoneal closure (SLPEC) of hernia sac high ligation using an ordinary taper needle: a novel technique for pediatric inguinal hernia

PURPOSE

Laparoscopic high ligation of the internal inguinal ring is an alternative procedure for treatment of pediatric inguinal hernia (PIH), with a major trend toward increasing use of extracorporeal knotting and decreasing use of working ports. We have utilized this laparoscopic technique to treat the entire spectrum of PIH (including incarcerated cases) for more than 17 years, and the technique continues to evolve and improve. We herein report our latest modification of this minimally invasive technique, namely single-site laparoscopic percutaneous extraperitoneal closure (SLPEC) of hernia sac high ligation using an ordinary taper needle, and evaluate its safety and efficacy.

METHODS

From July 2016 to July 2019, 790 children with indirect PIH were treated by laparoscopic surgery. All patients underwent high ligation surgery with a modified single-site laparoscopic technique mainly performed by extracorporeal suturing with an ordinary closed-eye taper needle (1/2 arc 11 × 34). The clinical data were retrospectively analyzed.

RESULTS

All surgeries were successful without serious complications. A contralateral patent processus vaginalis (CPPV) was found intraoperatively and subsequently repaired in 190 patients (25.4%). The mean operative time was 15 min (8-25 min) for 557 unilateral hernias and 21 min (14-36 min) for 233 bilateral hernias. The mean postoperative stay was 20 h. Minor complications occurred in five patients (0.63%) and were managed properly, with no major impact on the final outcomes. No recurrence was noted in the patients who were followed up for 6-42 months. No obvious scar was present postoperatively.

CONCLUSION

Modified SLPEC of hernia sac high ligation using an ordinary taper needle for repair of indirect PIH is a safe, reliable, and minimally invasive procedure with satisfactory outcome, with no special device being needed. It is easy to learn and perform and is worthy of popularization in the clinical setting.

Genetic diversity of strawberry mild yellow edge virus from eastern Canada

Strawberry mild yellow edge virus (SMYEV) is a member of the genus Potexvirus, family Alphaflexiviridae. It is one of the most common pathogenic viruses infecting cultivated strawberries worldwide. In this study, we investigated the genetic diversity of SMYEV in strawberry fields that were severely affected by strawberry decline disease in the eastern Canadian provinces of New Brunswick, Nova Scotia, Prince Edward Island and Quebec. A total of 134 SMYEV coat protein (CP) gene sequences, representing 85 nucleic acid haplotypes, were identified in 56 field samples. A highly divergent SMYEV population was found in all four provinces, but there was little genetic differentiation among the populations, and moreover, the Canadian SMYEV isolates formed a unique dissimilar, genetically divergent population group when compared to those reported in other countries. Phylogenetic analysis revealed three new SMYEV subclades that consisted mainly of Canadian variants and were composed of 76 sequence haplotypes (76/85, 88%). Mixed infections by different SMYEV variants were observed in 38 samples (38/56, 68%). Evolutionary analysis suggested that the SMYEV strains in eastern Canada possibly originated outside of Canada but adapted to conditions in the region through genetic mutations.

Potato Tuber Necrosis Induced by Alfalfa Mosaic Virus Depends on Potato Cultivar Rather Than on Virus Strain

Alfalfa mosaic virus (AMV) was identified as the causal agent of internal tuber necrosis in the potato cultivar Innovator in New Brunswick, Canada. Further pathological characterization of the isolate (designated as isolate CaM) was performed on six potato cultivars and one breeding clone. Upon mechanical inoculation, four cultivars (Innovator, Yukon Gold, Rochdale Gold-Dorée, and Shepody) showed needle-sized necrotic spots and increasing calico symptoms on new leaves, whereas the remaining cultivars only developed calico symptoms on new leaves. All tubers of CaM-infected Innovator and Shepody plants developed sporadic internal necrotic spots, as did ca. 23 and 8% tubers of CaM-infected Yukon Gold and Rochdale Gold-Dorée, respectively. Sequence analysis of the CP gene of CaM with AMV isolates from potato, all presumed belonging to the "non-necrotic" strain and retrieved from GenBank, indicated that CaM shared >97.1% sequence identity with all but four Egyptian isolates. At the complete genome level, phylogenetic analysis of all available sequences demonstrated that RNA 1 and RNA 3 can be grouped into three major clades each, whereas RNA 2 can be clustered into two clades. CaM and Ca175-1, an AMV isolate that was deemed non-necrotic in a previous study, had different phylogenetic clade patterns, indicating different RNA 1-RNA 2-RNA 3 haplotypes: IA-I-IB (CaM) versus Ca175-1 (IB-II-IA). Despite the difference in haplotype composition, CaM and Ca175-1 induced similar levels of internal necrosis in tubers of Innovator and its parent Shepody. The results suggest that the internal necrosis in AMV-infected tubers depends on potato cultivar rather than on AMV strain/haplotype, and CaM is just a "regular" isolate of AMV.

Rapid and sensitive detection of potato virus Y by isothermal reverse transcription-recombinase polymerase amplification assay in potato

In this study, an isothermal reverse transcription-recombinase polymerase amplification (RT-RPA) assay was developed for the efficient and accurate detection of potato virus Y (PVY) under isothermal conditions. This RT-RPA assay was more efficient than the conventional reverse transcription-polymerase chain reaction (RT-PCR) assay as the amplification reaction can be completed in less than 20 min. Moreover, unlike PCR that requires a thermocycler to carry out the DNA amplification through specific temperature phases, RPA assay could be performed under an isothermal condition at a temperature ranging from 25 to 40 °C. A simple instrumentation such as a heating block or a water bath or even anon-instrumental condition such as human hands or a benchtop inside/outside a room during the summer could satisfy the temperature requirement of RPA. The sensitivity of this assay was equivalent to that of the conventional RT-PCR, and the virus can be detected in a minimum of 2 pg of total RNA extracted from the PVY infected potato leaf tissues. The efficacy of the newly developed RT-RPA was then evaluated using field potato leaf and dormancy-broken sprout samples upon enzyme-linked immunosorbent assay (ELISA) screening. Of the 164 PVY-ELISA-positive samples, RT-RPA detected 157 whereas simplex RT-PCR detected 160 and multiplex RT-PCR detected 154. Of the 74 randomly selected PVY-ELISA-negative samples, RT-RPA, simplex RT-PCR and multiplex RT-PCR led to 1, 1 and 0 positive detections, receptively. Overall, RT-RPA and the two RT-PCR assays as well as ELISA exhibited an agreement of 96.6-98.7%, thus demonstrating the suitability of RT-RPA for large scale detection of PVY, irrespective of the strain type of the virus.

Proliferation of Recombinant PVY Strains in Two Potato-Producing Regions of Canada, and Symptom Expression in 30 Important Potato Varieties with Different PVY Strains

Potato virus Y (PVY) exists as several strains with distinct symptomology and tuber yield effects in different potato varieties. Recently, new recombinant strains have proliferated and dominated local populations around the world. In this study, PVY^O, PVY^N:O, PVY^N-Wi, and PVY^NTN strains were tracked across Canada from 2014 to 2017, showing rapid evolution of populations away from the traditionally dominant PVY^O to recombinants PVY^N-Wi (western Canada) and PVY^NTN (eastern Canada). Simultaneously, 30 potato varieties were inoculated with PVY^O, PVY^N:O, and PVY^NTN in controlled greenhouse experiments. Foliar symptoms of primary (mechanical inoculation mimicking aphid infection) and secondary (tuber seedborne) infection were cataloged, and tuber yield measured. On average, and generally similar in primary and secondary infection, symptom expression and yield reduction were most severe with PVY^O, followed by PVY^N:O and PVY^NTN. Strong mosaic symptoms were most commonly expressed with PVY^O infection, and only seen with PVY^N:O or PVY^NTN in 15 and 3 varieties, respectively. Across variety-strain combinations, yield reduction was correlated with symptom severity, most strongly in PVY^O-infected plants (e.g., AC Chaleur, Beljade, Envol, Norland, and Pacific Russet), and four varieties exhibited tuber necrotic ringspot disease with PVY^NTN (AC Chaleur, Envol, Pacific Russet, and Yukon Gold).

Molecular Evolutionary Analysis of Potato Virus Y Infecting Potato Based on the VPg Gene

Potato virus Y (PVY) is an important plant pathogen infecting solanaceous crops, causing significant losses to global potato and tobacco production. Some aspects of the plant pathology and molecular biology of PVY have been studied intensively, but the evolutionary dynamics of this virus are poorly understood. Here, we performed a comprehensive set of rigorous evolutionary analyses using 177 nucleotide sequences of the viral genome linked protein (VPg) gene, which interacts with the plant eukaryotic translation initiation factor 4E (eIF4E). Our Bayesian analysis reveals that the VPg gene of PVY has been evolving at a rate of 5.60 × 10^–4 subs/site/year (95% credibility interval 3.35 × 10^–4–8.17 × 10^–4), which is equivalent to those of other plant-infecting RNA viruses. We identified different evolutionary constraints on the two clades of PVY, clade N and clade O, whose diverge time were estimated at the year 1861 CE (95% credibility interval 1750–1948 CE). We also found that genetic variations were correlated with geographic regions, suggesting that the evolution of this pathogen is strongly affected by geographical associated factors. Taken together, the results of our study have potential implications for the control strategies of PVY.

Genetic Diversity of Potato virus Y in Potato Production Areas in Northeast China

In 2011-2014, ELISA or nucleic acid spot hybridization (NASH) testing for common potato viruses or Potato spindle tuber viroid (PSTVd) was performed on 500 leaf samples collected in potato fields in the northeast provinces Heilongjiang and Inner Mongolia, China. The results revealed that 38.4% (Heilongjiang) and 27.7% (Inner Mongolia) were positive for Potato virus Y (PVY). To unveil the strain composition and population structure of PVY in the region, the multiplex RT-PCR described by Chikh-Ali et al. was performed on all of the ELISA-PVY-positive samples. Of the 158 samples whose PVY strain scenarios could be determined, PVY^NTN-NW-SYR-II and PVY^N-Wi were the most abundant strains, occurring in 58.9 and 47.5% samples, followed by PVY^NTN-NW-SYR-I (31.0%), PVY^N:O (19.6%), Eu-PVY^NTN (7.6%), NA-PVY^N (1.3%), and PVY^O (0.6%). In the 84 single-strain-infected samples, PVY^N-Wi accounted for 41.7%, PVY^NTN-NW-SYR-II for 40.5%, PVY^NTN-NW-SYR-I for 14.3%, and PVY^N:O and Eu-PVY^NTN for 3.6% each. Seven isolates representing PVY^NTN-NW-SYR-I (HLJ-6-1 and HLJ-9-4), PVY^NTN-NW-SYR-II (INM-W-369-12 and SC-1-1-2), PVY^N:O (HLJ-30-2), and PVY^N-Wi (HLJ-BDH-2 and HLJ-C-429) were sequenced and analyzed molecularly. Whereas the sequence identities for isolates belonging to the same strain group were >98.5%, they fell for isolates belonging to different strain groups to 92.7-98.1% at the genome level and 96.1-98.4% at the polyprotein level. Interestingly, the exact location of the recombination events varied among isolates within a strain group. Phylogenetic analysis of all 42 full length PVY sequences from China indicated that most clustered to various recombinant groups, despite the fact that the PVY isolates were isolated from at least five host species. Pathological analysis of four isolates representing PVY^N:O, PVY^N-Wi, PVY^NTN-NW-SYR-I, and PVY^NTN-NW-SYR-II revealed that the PVY^NTN-NW-SYR-II isolate incited the most severe symptoms on potato cultivar Kexin 13, followed by PVY^NTN-NW-SYR-I, PVY^N:O and PVY^N-Wi. The PVY^NTN-NW-SYR-I and PVY^NTN-NW-SYR-II isolates also caused necrotic ringspots on the tubers of Kexin 13, indicating their ability to induce the potato tuber necrotic ringspot disease in potato.

Association of Fruit and Vegetable Intake and Frailty among Chinese Elders: A Cross-Sectional Study in Three Cities

OBJECTIVES

To examine the association of FVI and frailty in Chinese elders.

DESIGN

A sectional study was conducted in three cities (Shanghai, Zhengzhou, and Baoji) in China from June 2017 to June 2018.

PARTICIPANTS

A total of 5699 participants from 49 districts were included in the current study by two-stage sampling methods.

MEASUREMENTS

Frailty was measured by a validated Chinese version of the FRAIL scale. FVI per day was measured by two single questions.

RESULTS

The sample proportion with sufficient fruit intake was 36.7%, and 44.7% reported sufficient vegetable intake. The sample proportions that were robust, pre-frail, and frail were 43.6%, 38.3%, and 18.1%, respectively. Compared with low FVI, after including covariates, the odds ratio (OR) of frailty was 0.84 (95% CI: 0.73-0.97) for moderate fruit intake and 0.81 (95% CI: 0.70-0.94) for enough fruit intake; the OR of frailty was 0.83 (95% CI: 0.68-0.91) for moderate vegetable intake and 0.77 (95% CI: 0.64-0.93) for enough vegetable intake.

CONCLUSION

High FVI was negatively associated with the OR of frailty in Chinese elders. This finding implies it is important to promote FVI among adults to prevent frailty.

[HER2 status in gastric adenocarcinoma of Chinese: a multicenter study of 40 842 patients]

Objective: To investigation HER2 status in gastric adenocarcinoma of Chinese and contributing factors to the HER2 expression. Methods: HER2 status of 40 842 gastric adenocarcinomas and clinical data were retrospectively collected from 23 hospitals dated from 2013 to 2016. The association between HER2 positivity and clinicopathologic features was analyzed. Results: Of the 40 842 patients the median age was 62 years, the male female ratio was 2.6∶1.0. The rate of HER2 positivity was 8.8% (3 577/40 842). HER2 expression was related to the tissue type, tumor location, Lauren classification and tumor differentiation (P values: 0.009, 0.001, <0.01 and <0.01, respectively). Different HER2 expression status was observed between primary and recurrent tumors in 7.6% (48/635) cases. The rates of HER2 positivity ranged from 2% to 10% among different institutions. The rates of HER2 FISH amplification were dramatically different among the 23 hospitals (0-100%) with an average rate of 10% (810/8 156) in patients with HER2 IHC 2+ . Conclusions: HER2 expression is associated with clinicopathologic characteristics. HER2 re-assessment of tumor tissue and use of in situ hybridization techniques increase HER2 positivity. The current retrospective study should reflect the HER2 status in gastric adenocarcinoma of Chinese patients.

Epithelial Cdc42 Deletion Induced Enamel Organ Defects and Cystogenesis

Cdc42, a Rho family small GTPase, regulates cytoskeleton organization, vesicle trafficking, and other cellular processes in development and homeostasis. However, Cdc42's roles in prenatal tooth development remain elusive. Here, we investigated Cdc42 functions in mouse enamel organ. Cdc42 showed highly dynamic temporospatial patterns in the developing enamel organ, with robust expression in the outer enamel epithelium, stellate reticulum (SR), and stratum intermedium layers. Strikingly, epithelium-specific Cdc42 deletion resulted in cystic lesions in the enamel organ. Cystic lesions were first noted at embryonic day 15.5 and progressively enlarged during gestation. At birth, cystic lesions occupied the bulk of the entire enamel organ, with intracystic erythrocyte accumulation. Ameloblast differentiation was retarded upon epithelial Cdc42 deletion. Apoptosis occurred in the Cdc42 mutant enamel organ prior to and synchronously with cystogenesis. Transmission electron microscopy examination showed disrupted actin assemblies, aberrant desmosomes, and significantly fewer cell junctions in the SR cells of Cdc42 mutants than littermate controls. Autophagosomes were present in the SR cells of Cdc42 mutants relative to the virtual absence of autophagosome in the SR cells of littermate controls. Epithelium-specific Cdc42 deletion attenuated Wnt/β-catenin and Shh signaling in dental epithelium and induced aberrant Sox2 expression in the secondary enamel knot. These findings suggest that excessive cell death and disrupted cell-cell connections may be among multiple factors responsible for the observed cystic lesions in Cdc42 mutant enamel organs. Taken together, Cdc42 exerts multidimensional and pivotal roles in enamel organ development and is particularly required for cell survival and tooth morphogenesis.

Abdominal wall reconstruction following resection of large abdominal aggressive neoplasms using tensor fascia lata flap with or without mesh reinforcement

PURPOSE

Abdominal wall defects caused by neoplasms with large extended resection defects remain a challenging problem. Autologous flaps, meshes, and component separation techniques are effective in reconstructing these defects. We retrospectively reviewed and assessed the success of reconstruction using tensor fascia lata flap with or without meshes.

METHODS

18 patients with abdominal wall neoplasms were identified during the period from 2007 to 2016. A retrospective review of office charts and hospital records was performed.

RESULTS

A total of 18 patients received corresponding treatment according to the degree of defects, with a mean age of 53.89 ± 14.56 years old, a mean body mass index (BMI) of 22.89 ± 4.09 kg/m², and a mean American Society of Anesthesiologist (ASA) score of 2.18 ± 0.75. Operative details included the mean defect size (303.44 ± 175.67 cm²), the mean mesh size (265.92 ± 227.99 cm²), and the mean operative time (382.33 ± 180.38 min). Postoperative wound complications were identified in 7 (39%) patients, including incisional infection, edema and thrombus. Neoplasm recurrence was observed in 2 (13%) primary neoplasms patients. No hernias were present in any patient.

CONCLUSIONS

Abdominal wall defects caused by neoplasms should be repaired by autologous flaps combined with or without mesh reinforcement. Most type I defects should be primary sutured; type II or III defects should be repaired well by flaps, with or without mesh; if the incision is infected or contaminated, biological mesh or flaps are the best choice.

High Resolution DNA Melting Assays for Detection of Rx1 and Rx2 for High-Throughput Marker-Assisted Selection for Extreme Resistance to Potato virus X in Tetraploid Potato

Assessment of the existing PCR-gel electrophoresis-based methods for detection of Rx1 and Rx2, the genes that independently control extreme resistance (ER) to Potato virus X (PVX), indicated that the 5Rx1F/5Rx1R primer pair led to reliable detection of Rx1, whereas the 106Rx2F/106Rx2R primer pair detected Rx2 despite some nonspecific reactions in potato clones/cultivars without Rx2. However, the methodology is time consuming and does not differentiate the absence of Rx1/Rx2 from a failed PCR reaction. A newly designed primer pair that targets Rx1 and Rx2 as well as rx1 and rx2 produced an amplicon for all alleles. When the primer pair was combined with 5Rx1F/5Rx1R, respective amplicons were produced, although they were not distinguishable by regular agarose gel electrophoresis. When subjected to a high-resolution DNA melting (HRM) assay, two distinct melting profiles for Rx1 and rx1, respectively, were detected. Triplex PCR-gel electrophoresis and -HRM assay for detection of Rx1, Rx2, and rx1/rx2 were also performed. The efficacy of the HRM assays were validated in potato cultivars/clones with known phenotypes, indicating its potential for high-throughput selection of potato clones/cultivars carrying Rx1 or Rx2. Duplex PCR-HRM assays of over 600 progeny from 12 crosses involving various parents correctly detected the presence or absence of Rx1 in each progeny, allowing accurate prediction of the phenotype. Progeny that tested positive for Rx1 by HRM exhibited ER to PVX whereas progeny that tested negative for Rx1 were susceptible to PVX infection. The genotype of each parent and the possible presence of Nx in two Rx1-possessing parents are also discussed.

Sequence identification, serological reactivity and family genetics of a novel HLA allele, HLA-A*26:82

HLA-A*26:82 was identified by sequence-based typing and showed the serological specificity of A26.

Evaluation of attenuation correction in cardiac PET using PET/MR

BACKGROUND

Simultaneous acquisition Positron emission tomography/magnetic resonance (PET/MR) is a new technology that has potential as a tool both in research and clinical diagnosis. However, cardiac PET acquisition has not yet been validated using MR imaging for attenuation correction (AC). The goal of this study is to evaluate the feasibility of PET imaging using a standard 2-point Dixon volume interpolated breathhold examination (VIBE) MR sequence for AC.

METHODS AND RESULTS

Evaluation was performed in both phantom and patient data. A chest phantom containing heart, lungs, and a lesion insert was scanned by both PET/MR and PET/CT. In addition, 30 patients underwent whole-body 18F-fluorodeoxyglucose PET/CT followed by simultaneous cardiac PET/MR. Phantom study showed 3% reduction of activity values in the myocardium due to the non-inclusion of the phased array coil in the AC. In patient scans, average standardized uptake values (SUVs) obtained by PET/CT and PET/MR showed no significant difference (n = 30, 4.6 ± 3.5 vs 4.7 ± 2.8, P = 0.47). There was excellent per patient correlation between the values acquired by PET/CT and PET/MR (R 2 = 0.97).

CONCLUSIONS

Myocardial SUVs PET imaging using MR for AC shows excellent correlation with myocardial SUVs obtained by standard PET/CT imaging. The 2-point Dixon VIBE MR technique can be used for AC in simultaneous PET/MR data acquisition.

Strawberry vein banding virus isolates in eastern Canada are molecularly divergent from other isolates

The complete sequence of a strawberry vein banding virus (SVBV) isolate collected in Nova Scotia, Canada, and designated NS8, was determined. The 7,856-nucleotide circular double-stranded DNA genome contains seven open-reading frames (ORFs), which is consistent with other SVBV isolates and other members of the genus Caulimovirus. Comparison of NS8 with other whole-genome sequences retrieved from databases revealed that NS8 shares the highest sequence similarity (96.5% identity) with isolate China (accession number HE681085) and the lowest (88.3% identity) with clone pSVBV-E3 (accession number X97304). Despite the overall high sequence similarity between NS8 and China, the coat protein encoding ORF IV of NS8 shares only 90.9% sequence identity with the China isolate. Phylogenetic analysis at the complete-genome level placed NS8 and all Chinese isolates in one clade and clone pSVBV-E3 in a separate clade. Interestingly, phylogenetic analysis of all available ORF IV sequences, including those retrieved from databases and newly sequenced samples in this study from Canada, revealed three distinct clades. All Canadian isolates grouped together as one clade, pSVBV-E3 and several others from Europe, Egypt and the USA grouped as a second clade, and isolates from China formed a third clade. These results demonstrate that SVBV is more divergent than previously reported.

Development and Validation of High-Resolution Melting Markers Derived from Rysto STS Markers for High-Throughput Marker-Assisted Selection of Potato Carrying Rysto

Sequence analysis of the chromosome region harboring the sequence-tagged site (STS) markers YES3-3A and YES3-3B for Ry_sto, a gene responsible for extreme resistance to Potato virus Y (PVY) in potato, was performed in tetraploid potato 'Barbara' (Rrrr) and 'AC Chaleur' (rrrr) as well as their progeny selections. Three and two sequence variants were identified in Barbara resistant (R) selections and AC Chaleur susceptible (S) selections, respectively. Further analysis indicates that the variant with a 21-nucleotide (nt) deletion is likely the chromosome copy harboring the STS markers. Two primer pairs, one targeting the region containing a 20-nt deletion and the other targeting the region anchoring the YES3-3A reverse primer, were designed. As anticipated, pair one produced two visible fragments in Barbara-R bulk and one visible fragment in AC Chaleur-S bulk; pair two produced one visible fragment in all samples. When subjected to high-resolution melting (HRM) analysis, two distinct melting profiles for R and S samples were observed. Analysis of 147 progeny of Barbara × AC Chaleur revealed 72 and 75 progeny with R and S melting profiles, respectively, which was consistent with YES3-3A and YES3-3B assays and phenotyping analysis, thus demonstrating the potential of HRM profiles as novel molecular markers for Ry_sto. The efficacy of the newly developed HRM markers for high-throughput marker-assisted selection for Ry_sto-conferred resistance to PVY was validated further with three populations involving Barbara as the R parent.

RT-PCR Differentiation, Molecular and Pathological Characterization of Andean and Ordinary Strains of Potato virus S in Potatoes in China

A survey of potatoes in a field in Hubei, China, for common potato viruses revealed that Potato virus S (PVS) was the most abundant virus. To unveil the strain identity of the virus, primers specific to the ordinary and/or Andean strains of PVS (i.e., PVS^O and PVS^A) were designed. RT-PCR using these primers successfully detected PVS^O and PVS^A in the samples. Sequence analysis of the amplicons confirmed the correctness of the RT-PCR assay. Two isolates, PVS HB24 and PVS HB7, representing PVS^O and PVS^A, respectively, were chosen for molecular and biological characterization. Both isolates contained a genome of 8,453 nt in length with six open reading frames. They shared a sequence identity of 79.5% at the complete genome sequence level. Phylogenetic analysis placed PVS HB24 and PVS HB7 to PVS^O and PVS^A clades, respectively. PVS HB24 induced chlorotic local lesions on the inoculated leaves but no visible symptom on the upper uninoculated leaves of Chenopodium quinoa after mechanical inoculation, whereas PVS HB7 induced both local and systemic symptoms on C. quinoa. ELISA and RT-PCR confirmed that PVS HB7 infected C. quinoa systemically whereas PVS HB24 failed to do so. Both isolates infected potato cv. Shepody and Solanum chacoense asymptomatically, but did not infect Nicotiana occidentalis and N. tobaccum cv. Samsun.

Pioglitazone Enhances the Beneficial Effects of Glucocorticoids in Experimental Nephrotic Syndrome

Glucocorticoids are the primary therapy for nephrotic syndrome (NS), but have serious side effects and are ineffective in ~20-50% of patients. Thiazolidinediones have recently been suggested to be renoprotective, and to modulate podocyte glucocorticoid-mediated nuclear receptor signaling. We hypothesized that thiazolidinediones could enhance glucocorticoid efficacy in NS. We found that puromycin aminonucleoside-induced proteinuria in rats was significantly reduced by both high-dose glucocorticoids (79%) and pioglitazone (61%), but not low-dose glucocorticoids (25%). Remarkably, pioglitazone + low-dose glucocorticoids also reduced proteinuria (63%) comparably to high-dose glucocorticoids, whereas pioglitazone + high-dose glucocorticoids reduced proteinuria to almost control levels (97%). Molecular analysis revealed that both glucocorticoids and pioglitazone enhanced glomerular synaptopodin and nephrin expression, and reduced COX-2 expression, after injury. Furthermore, the glomerular phosphorylation of glucocorticoid receptor and Akt, but not PPARγ, correlated with treatment-induced reductions in proteinuria. Notably, clinical translation of these findings to a child with refractory NS by the addition of pioglitazone to the treatment correlated with marked reductions in both proteinuria (80%) and overall immunosuppression (64%). These findings together suggest that repurposing pioglitazone could potentially enhance the proteinuria-reducing effects of glucocorticoids during NS treatment.

Host recovery and reduced virus level in the upper leaves after Potato virus Y infection occur in tobacco and tomato but not in potato plants

In this study, the recovery phenomenon following infection with Potato virus Y (PVY) was investigated in tobacco (Nicotiana tobaccum), tomato (Solanum lycopersicum) and potato (Solanum tuberosum) plants. In tobacco plants, infection of severe strains of PVY (PVYN or PVYN:O) induced conspicuous vein clearing and leaf deformation in the first three leaves above the inoculated leaves, but much milder symptoms in the upper leaves. The recovery phenotype was not obvious in tobacco plants infected with PVY strain that induce mild symptoms (PVYO). However, regardless of the virus strains, reduction in PVY RNA levels was similarly observed in the upper leaves of these plants. Removal of the first three leaves above the inoculated leaves interfered with the occurrence of recovery, suggesting that the signal(s) mediating the recovery is likely generated in these leaves. In PVYN or PVYN:O but not in PVYO-infected tobacco plants, the expression of PR-1a transcripts were correlated with the accumulation level of PVY RNA. Reduced level of PVY RNA in the upper leaves was also observed in infected tomato plants, whereas such phenomenon was not observed in potato plants. PVY-derived small RNAs were detected in both tobacco and potato plants and their accumulation levels were correlated with PVY RNA levels. Our results demonstrate that the recovery phenotype following PVY infection is host-specific and not necessarily associated with the expression of PR-1a and generation of PVY small RNAs.

RT-PCR and real-time RT-PCR methods for the detection of potato virus Y in potato leaves and tubers

Potato virus Y (PVY) is a major threat to potato crops around the world. It is an RNA virus of the family Potyviridae, exhibiting many different strains that cause a range of symptoms in potato. ELISA detection of viral proteins has traditionally been used to quantify virus incidence in a crop or seed lot. ELISA, however, cannot reliably detect the virus directly in dormant tubers, requiring several weeks of sprouting tubers to produce detectable levels of virus. Nor can ELISA fully discriminate between the wide range of strains of the virus. Several techniques for directly detecting the viral RNA have been developed which allow rapid detection of PVY in leaf or tuber tissue, and that can be used to easily distinguish between different strains of the virus. Described in this chapter are several protocols for the extraction of RNA from leaf and tuber tissues, and three detection methods based upon reverse-transcription-PCR (RT-PCR). First described is a traditional two-step protocol with separate reverse transcription of viral RNA into cDNA, then PCR to amplify the viral cDNA fragment. Second described is a one-step RT-PCR protocol combining the cDNA production and PCR in one tube and one step, which greatly reduces material and labor costs for PVY detection. The third protocol is a real-time RT-PCR procedure which not only saves on labor but also allows for more precise quantification of PVY titre. The three protocols are described in detail, and accompanied with a discussion of their relative advantages, costs, and possibilities for cost-saving modifications. While these techniques have primarily been developed for large-scale screening of many samples for determining viral incidence in commercial fields or seed lots, they are also amenable to use in smaller-scale research applications.

Molecular characterization of a Chinese isolate of potato virus A (PVA) and evidence of a genome recombination event between PVA variants at the 3'-proximal end of the genome

Potato plants that exhibited mosaic symptoms were collected in Xiangxi, Hunan province, China. Multiplex RT-PCR screening for common viruses revealed the presence of potato virus A (PVA) in these samples. ELISA with virus-specific antibodies confirmed infection by PVA in the plants. Rod-shaped virions of ~750 nm in length and ~13 nm in width were observed by transmission electron microscopy. One virus isolate (designated PVA-Hunan) was subjected to molecular characterization. The viral genome consisted of 9,567 nucleotides, excluding the poly(A) tail, and encoded a polyprotein of 3,059 amino acids. A second characteristic potyvirus open reading frame (ORF), pretty interesting Potyviridae ORF (pipo), was located at nucleotides 2,834-3,139. The isolate shared 84% to 98% and 93% to 99% sequence identity with other PVA isolates at the nucleotide and amino acid level, respectively. Phylogenetic analysis demonstrated that, within the PVA group, PVA-Hunan clustered most closely with the Finnish isolate Her, then with isolates 143, U, Ali, M and B11. The isolate TamMV stood alone at a separate branch. However, scanning of complete genome sequences using SimPlot revealed 99%-sequence identity between PVA-Hunan and TamMV in the 3'-proximal end of the genome (~nt 9,160 to the 3'end) and a 50%-94% (average~83%) identity upstream of nt 9,160. In contrast, 98% identity between PVA-Hunan and isolates M and B11 was detected for nucleotides 1 to ~9,160, but only ~94% for the 3'-proximal region, suggesting a genome recombination event (RE) at nt 9,133. The recombination breakpoint also was identified by the Recombination Detection Program (RDP). The RE was further confirmed by analysis of the CP gene, where the apparent RE was located.

Effects of Crop Management Practices on Current-Season Spread of Potato virus Y

The current-season spread of Potato virus Y (PVY) was monitored in 19 fields under various management practices in New Brunswick, Canada, through the 2011 and 2012 growing seasons. The focus of this study was to evaluate the role of seedborne PVY inoculum, aphid vector abundance, and the numbers, timing, and types of insecticide and mineral oil sprays, and to confirm the reliability and forecasting capacity of midseason PVY testing. In each field, 100 to 110 virus-free plants were identified shortly after emergence and were assessed four times from early July to early September (after top-kill) with enzyme-linked immunosorbent assay (ELISA) and reverse-transcription polymerase chain reaction (RT-PCR) to track PVY spread. In addition, tubers harvested during development in August and after top-kill were grown-out in the greenhouse for ELISA testing. PVY spread to selected virus-free plants varied widely, ranging from 0 to 76.2% across all studied fields. Of the 19 fields over two seasons, 10 fields were planted with no detectable seedborne PVY, and they showed 0 to 8.7% (mean 2.9%) PVY spread by harvest. The remaining nine study fields with 0.9 to 5.8% seedborne PVY showed 1 to 76.2% (mean 15.2%) PVY spread by harvest. PVY spread was detected in most fields during midseason testing with ELISA and RT-PCR; all tests correlated well with final PVY rates after top-kill, though RT-PCR detection in developing tubers was most sensitive and correlated. Logistic regression modeling was used to identify major factors in PVY spread, including seedborne PVY, early-season aphid abundance, and the numbers of insecticide and mineral oil sprays. The best-fitting model, constructed using these factors as well as a measurement of July PVY incidence (ELISA_July), strongly explained PVY spread by harvest, with the most significant management factor being the number of mineral oil sprays supplemented with insecticide used during the growing season. A similar model fitted without the ELISA_July did not adequately predict ultimate PVY spread. The analysis suggests that mineral oil alone was effective at lowering PVY spread, and more effective when combined with insecticide, particularly when used early in the season. No evidence was found for differences in PVY spread across the eight cultivars used or across the range of mineral oil application rates, whereas some evidence was found for differences in the effectiveness of different insecticide types.

Effects of pulsed Nd:YAG laser on tensile bond strength and caries resistance of human enamel

This study aims to evaluate the effects of pulsed Nd:YAG laser on the tensile bond strength (TBS) of resin to human enamel and caries resistance of human enamel. A total of 201 human premolars were used in this in vitro study. A flat enamel surface greater than 4 × 4 mm in area was prepared on each specimen using a low-speed cutting machine under a water coolant. Twenty-one specimens were divided into seven groups for morphology observations with no treatment, 35% phosphoric acid etching (30 seconds), and laser irradiation (30 seconds) of pulsed Nd:YAG laser with five different laser-parameter combinations. Another 100 specimens were used for TBS testing. They were embedded in self-cured acrylic resin and randomly divided into 10 groups. After enamel surface pretreatments according to the group design, resin was applied. The TBS values were tested using a universal testing machine. The other 80 specimens were randomly divided into eight groups for acid resistance evaluation. Scanning electron microscope (SEM) results showed that the enamel surfaces treated with 1.5 W/20 Hz and 2.0 W/20 Hz showed more etching-like appearance than those with other laser-parameter combinations. The laser-parameter combinations of 1.5 W/15 Hz and 1.5 W/20 Hz were found to be efficient for the TBS test. The mean TBS value of 14.45 ± 1.67 MPa in the laser irradiated group was significantly higher than that in the untreated group (3.48 ± 0.35 MPa) but lower than that in the 35% phosphoric acid group (21.50 ± 3.02 MPa). The highest mean TBS value of 26.64 ± 5.22 MPa was identified in the combination group (laser irradiation and then acid etching). Acid resistance evaluation showed that the pulsed Nd:YAG laser was efficient in preventing enamel demineralization. The SEM results of the fractured enamel surfaces, resin/enamel interfaces, and demineralization depths were consistent with those of the TBS test and the acid resistance evaluation. Pulsed Nd:YAG laser as an enamel surface pretreatment method presents a potential clinical application, especially for the caries-susceptible population or individuals with recently bleached teeth.