[Association of nutritional status with clinical outcomes of stroke patients with acute anterior circulation large vessel occlusion after emergency endovascular treatment]

OBJECTIVE

To explore the influence of nutritional status on 90-day functional outcomes of stroke patients with acute large vessel occlusion in the anterior circulation after endovascular treatment (EVT).

METHODS

We retrospectively analyzed the baseline, laboratory, surgical and 90-day follow-up data of patients with stroke resulting from acute large vessel occlusion in the anterior circulation, who underwent emergency endovascular treatment in our hospital from July, 2015 to December, 2020. A favorable outcome was defined as a modified Rankin scale score ≤2 at 90 days. Univariate and multivariate regression analyses were performed to explore the relationship between nutritional status and 90-day functional outcomes of the patients.

RESULTS

A total of 459 patients (mean age of 68.29±11.21 years, including 260 males) were enrolled in this study. According to their prognostic nutritional index (PNI), the patients were divided into normal nutrition group (392 cases, 85.4%), moderate malnutrition group (44 cases, 9.6%), and severe malnutrition group (23 cases, 5.0%). Univariate analysis showed that the patients with good clinical outcomes had a lower proportion of malnutrition with a younger age, a lower rate of diabetes, lower baseline blood pressure, lower baseline NIHSS score, higher baseline ASPECT score, and higher rates of good collateral circulation and complete vascular recanalization. Multivariate analysis showed that in addition to age, diabetes, baseline systolic blood pressure, successful recanalization, baseline ASPECT score, baseline NIHSS score and collateral circulation, a greater PNI was a protective factor for a good 90-day outcome of patients after EVT (moderate vs severe: OR=0.245, 95% CI: 0.066-0.908, P=0.035; normal vs severe: OR=0.185, 95% CI: 0.059-0.581, P=0.004).

CONCLUSION

Nutritional status an important factor affecting the 90-day outcomes after EVT of stroke patients with acute large vessel occlusion in the anterior circulation.

[Determination of chlorobenzene metabolite-p-chlorophenol in urine by solid phase extraction-gas chromatography]

Objective: A method to determine chlorobenzene metabolite-p-chlorophenol in urine by solid phase extraction-gas chromatography was established. Methods: In May 2021, the urine sample was hydrolyzed at 100 ℃ for 1.5 h with 2 ml concentrated hydrochloric acid. After cooling and filtering, the sample was enriched and purified by Oasis(®)MAX 6cc SPE column. Drip washing with 0.01 mol/L hydrochloric acid solution and elution with acetonitrile, the eluent was volumized to 5 ml with acetonitrile and determined by gas chromatography, and quantify by standard curve method. Results: Calibration curve of the method was linear within the range of 1.61-80.30 μg/ml and showed good linearity with r=0.9997, the regression equation was y=1.51602x-0.10234. The determination limit was 0.17 μg/ml, and the limit of quantitation was 0.55 μg/ml. Recovery rates were between 89.3%-104.4%, the relative standard deviation (RSD) of intra-day measurements ranged from 4.3% to 6.7%, and the RSD of inter-day measurements ranged from 4.5% to 6.7%. Conclusion: This method could optimize sample pretreatment, and eliminate the interference of impurities, which is sensitive, efficient and accurate for the determination of chlorobenzene metabolite-p-chlorophenol in urine.

[Cardiovascular biomarkers improve precise risk assessment for cardiovascular diseases]

Cardiovascular diseases (CVD) is an urgent threat to Chinese. It is of primary importance to assess risk for cardiovascular diseases. However, there are some limitations about traditional tools for CVD risk assessment. Recently, numbers of clinical trials demonstrated that CVD risk assessments based on cardiovascular biomarkers would significantly improve sensitivity and specificity of prediction. The comment review the limitations of traditional tools for CVD risk assessment, the application value of novel tools and advances of cardiovascular biomarkers in CVD prediction. It is benefit for precise stratification and management of general population during risk stage. Archieving the strategic goal of"Healthy China"would be promising soon.

Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M_{⊙} and 1.0  M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200]  Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M_{⊙}<m_{PBH}<1.0  M_{⊙} is f_{PBH}≡Ω_{PBH}/Ω_{DM}≲6%. This improves existing constraints on primordial black hole abundance by a factor of ∼3. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_{min}=1  M_{⊙}, where f_{DBH}≡Ω_{DBH}/Ω_{DM}≲0.003%. These are the first constraints placed on dissipative dark models by subsolar-mass analyses.

Physical activity patterns, genetic susceptibility, and risk of hip/knee osteoarthritis: a prospective cohort study based on the UK Biobank

OBJECTIVES

The effect of physical activity on hip/knee osteoarthritis (OA) and how it varies by genetic susceptibility to OA remains inconclusive.

METHODS

In a cohort study of UK Biobank, 436,166 OA-free participants were recruited in 2006-2010 and followed for knee/hip OA until the end of 2020. 28 physical activity-related items were collected at baseline. Cox regression was used to estimate associations between physical activity behaviors, as well as major activity patterns (i.e., significant principal components[PCs] identified by principal component analysis), and risk of OA, adjusting for multiple confounders. We further stratified the analyses by polygenic risk score (PRS) for OA to examine the impact of genetic susceptibility to OA on the studied association.

RESULTS

During a mean follow-up of 11.15 years, 13,227 hip and 21,119 knee OA cases were identified. 19, out of 28, studied items showed associations with increased OA risk. Compared with low adherence group(<1^st tertile of PC score for each pattern), individuals with high adherence to five identified patterns were associated with increased risk of OA. The moderate adherence to "strenuous sports"(HR = 0.93, 95%CI: 0.89-0.97) and "walking for pleasure"(HR = 0.93, 95%CI: 0.89-0.98) patterns was associated with reduced OA. Similar risk patterns were obtained in the stratified analysis by PRS levels for OA.

CONCLUSION

High intensity of most activity patterns were associated with increased OA. However, a protective effect was suggested for moderate adherence to patterns of "strenuous sports" and "walking for pleasure" that consistent across different genetic susceptibilities, underscoring the potential benefits of moderate-intensity physical activity on OA.

[Preliminary evaluation on the efficacy of emergency transcatheter aortic valve replacement: a multicenter study]

Objectives: To explore the efficacy and safety of emergency transcatheter aortic valve replacement (TAVR). Methods: Data of patients who underwent emergency TAVR in eight centers, namely Fuwai Hospital, Wuhan Asia Heart Hospital, Xijing Hospital, Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology, Guangdong Provincial People's Hospital, Zhongshan Hospital Affiliated to Fudan University, the First Affiliated Hospital of Zhengzhou University, the Second Xiangya Hospital of Central South University, between May 2017 and December 2020 were retrospectively analyzed. The use of mechanical circulatory support system (MCS) and the results of laboratory tests (N-terminal B-type natriuretic peptide (NT-proBNP)) and echocardiography (mean aortic valve cross valve pressure difference and left ventricular ejection fraction) before and after operation were collected. The primary endpoint was all-cause death, and the secondary endpoints were stroke, major bleeding, major vascular complications, myocardial infarction, permanent pacemaker implantation, and acute renal injury. Device success was caculated, which refered to absence of procedural mortality and correct positioning of a single prosthetic heart valve into the proper anatomical location and intended performance of the prosthetic heart valve (mean aortic valve gradient<20 mmHg(1 mmHg=0.133 kPa) or peak velocity<3 m/s, with no moderate or severe prosthetic valve regurgitation). Kaplan-Meier survival curve was used to estimate the survival rate of patients during follow-up. Results: This study included 48 patients. The age was (72.5±8.1) years, and 34 patients were males (70.8%). Device success rate was 91.7% (44/48). The mean aortic valve transvalvular pressure was significantly decreased after operation ((12.3±6.4)mmHg vs. (60.2±23.8)mmHg, P<0.000 1). Left ventricular ejection fraction was significantly increased ((41.5±11.7)% vs. (31.0±11.3)%, P<0.000 1). NT-proBNP significantly decreased (3 492.0 (1 638.8, 7 165.5) ng/L vs. 12 418.5 (6 693.8, 35 000.0) ng/L, P<0.000 1). In-hospital all-cause mortality was 8.3% (4/48). During hospitalization, the rate of stroke was 2.1% (1/48), major bleeding was 6.3% (3/48), major vascular complications was 10.4% (5/48), myocardial infarction was 4.2% (2/48), permanent pacemaker implantation was 6.3% (3/48), and the rate of acute renal injury was 12.5% (6/48). MCS was used in 20 patients (41.7%). The median follow-up time was 196 days. During the follow-up, one patient died (due to systemic metastasis of pancreatic cancer), two cases suffered new myocardial infarction and one case received permanent pacemaker implantation. The survival rate of 30 days, 1 year and 2 years after the operation were 91.7% (44/48), 89.6% (43/48), 89.6% (43/48), respectively. Conclusion: Emergency TAVR may be a safe and effective treatment for patients with severe decompensated aortic valve stenosis.

[Single center experience of transcatheter aortic valve replacement with a simplified operative protocol]

Objective: To summarize the single center experience of transcatheter aortic valve replacement (TAVR) with a simplified operative protocol. Methods: Consecutive patients who underwent transfemoral TAVR (TF-TAVR) from July 2020 to December 2020 in Fuwai Hospital were retrospectively analyzed. We compared the baseline characteristic, procedure information, 30-day follow-up outcomes of the patients who underwent TF-TAVR without the simplified operative protocol (routine group) or with the simplified operative protocol (simplified protocol group). Results: 93 patients were collected, 42 patients belonging to routine group, 51 patients belonging to simplified protocol group. In simplified protocol group, there were 51 patients planned to use ultrasound-guided femoral access puncture, procedure was successful in all 51 patients (100%). There were 49 patients planned to use the radial artery as the secondary access, procedure was successful in 45 patients (92%). There were 48 patients planned to use the strategy of avoidance of urinary catheter, this strategy was achieved in 35 patients (73%). There were 12 patients planned to use the left ventricular guidewire to pace, procedure was successful in 11 patients (92%). There were no differences in baseline characteristics, major clinical endpoints and 30-day follow-up outcomes between the two groups. Meanwhile, the procedure time ((62.5±17.9)min vs. (78.3±16.7)min, P<0.001), operation room time ((133.7±25.1)min vs. (159.2±42.6)min, P<0.001), X-ray exposure time ((17.2±6.5)min vs. (20.2±7.7)min, P=0.027) were significantly shorten in simplified protocol group compared with the routine group. Conclusion: Our study results indicate that the simplified operative protocol of TF-TAVR is as effective and safe as the routine operative protocol, meanwhile using the simplified operative protocol can significantly increase the operative efficiency of TF-TAVR.

[Comparison of efficacy and safety between new oral anticoagulants and traditional anticoagulants in patients with liver cirrhosis requiring anticoagulant therapy]

Objective: To compare the advantages and disadvantages of new oral anticoagulants (NOACs) with traditional anticoagulants, in an attempt to evaluate their efficacy and safety in patients with liver cirrhosis requiring anticoagulant therapy. Methods: Relevant literatures were searched from PubMed, Embase, Cochrane Library, HowNet, Wanfang, VIP and other databases by computer retrieval. The literatures quality was evaluated by NOS. The extracted data were meta-analyzed by RevMan5.3 software. Results: A total of seven studies were included, including one randomized controlled trial and six retrospective cohort studies with a total of 3042 cases. Among them, 1677 and 1365 cases used NOACs and traditional anticoagulants. Meta-analysis results showed that compared with the traditional anticoagulant group, the NOACs group had a lower incidence of massive hemorrhage [OR=0.56, 95%CI (0.37-0.85), P＜0.01] and a higher thrombotic recanalization rate [OR=7.77, 95%CI (3.48~17.34), P＜0.01], and the difference was statistically significant, while there were no statistically significant differences between the two groups in comparison to all-cause bleeding rates [OR=0.72, 95%CI (0.13-3.91), P=0.07], all-cause mortality [OR=0.72, 95%CI (0.25-2.07), P=0.54], recurrent embolism and stroke rates [OR=0.90, 95%CI (0.59-1.39), and P=0.64]. Conclusion: Compared with traditional anticoagulants, NOACs have higher safety and better efficacy in the treatment of patients with liver cirrhosis, but it has not been widely used in China. Therefore, large-scale randomized controlled trials and prospective studies are further needed to confirm it in the future.

Assembly of Ultralong Hydroxyapatite Nanowires into Enamel-like Materials

To develop dental restorative materials with enamel-like structures, ultralong hydroxyapatite (HA) nanowires were synthesized by a hydrothermal method, followed by functionalization with 3-methacryloxypropyltrimethoxysilane (KH-570). The mixture of HA nanowires, KH-570, and light initiator was stirred and centrifuged. The precipitate was vacuum filtered to remove excessive KH-570 and then pressured under cold isostatic pressing (10 MPa × 24 h). Finally, the block was polymerized by lighting. Scanning electron microscopy and transmission electron microscopy showed that HA nanowires with aspect ratios >1,000 were assembled into enamel rod-like microstructures and evenly dispersed in the polymerized KH-570 silane matrix to form enamel-like structures. Thermogravimetric analysis demonstrated that the content of HA nanowires reached 72 wt% in the composite. The enamel-like composite showed a similar hardness, frictional property, and acid-etching property to those of enamel and a comparable or even better diametral tensile strength and compressive strength than some commercial composite resins in mechanical tests in vitro. In addition, the enamel-like composite had good cytocompatibility. Such enamel-like composites may have the potential to be used in biomimetic tooth restorations in the future.

POS0102 GLOBAL CHARACTERIZATION OF SALIVARY GLANDS IMMUNE MICROENVIRONMENT IN PRIMARY SJÖGREN’S SYNDROME BY SINGLE-CELL SEQUENCING

Background

Primary Sjögren’s syndrome (pSS) is a heterogeneous, chronic, complex systemic autoimmune disease. The hallmark symptom of the disease is exocrinopathy, chiefly salivary and lachrymal glands, which often results in dryness of the mouth and eyes. As of today, although a lot of genetic and epigenetic studies have reveal the complexity of pSS to a certain extent, but the knowledge of existing pSS disease heterogeneity is still limited and the immune mechanisms of salivary glands (SG) injury have been challenging to clarify.

Objectives

Single-cell RNA sequencing (scRNA-seq) is a powerful tool capable of defining cell types and states on the basis of their individual transcriptome in a given sample from health and disease. To characterize the salivary glands immune microenvironment of patients with pSS, we performed droplet-based single cell mRNA sequencing (scRNA-seq) (10X Genomics) to provide a deeper insight into the cellular and molecular characteristics of salivary glands from pSS patients.

Methods

11 patients and 5 non-pSS controls were recruited from the The First Affiliated Hospital of USTC. The non-pSS were subjects who had experienced subjective symptoms of dryness, but no not meet any of the classification criteria of pSS. The clinical characteristics and laboratory findings of enrolled patients were also collected. After resection, salivary glands tissue samples were obtained after labial gland biopsy, rapidly digested to a single-cell suspension and subjected to scRNA-seq using the 10X platform. After rigorous quality control (QC) definition, low-quality cells were filtered. Following gene expression normalization for read depth and mitochondrial read count, we applied principle component analysis on genes variably expressed across all 72,853 cell.

Results

A total of 72,853 cells were obtained from all salivary glands samples. Our results revealed 12 major unique cell populations of salivary glands cell, including T cells, B cells, plasma cells, epithelial cells, myoepithelial cells, endothelial cells, myofibroblast, pericytes, melanocytes, fibroblast, myeloid cells and a cluster of unknown cells. As expected, lymphocytes (T and B cell populations) were significant increase in the salivary glands of patients with pSS. For further subsets analysis, we identify 41 subsets, including novel subpopulations in cell types hitherto considered to be homogeneous, as well as transcription factors underlying their heterogeneity. Strikingly, we found that differentially expressed genes (DEGs) that myoepithelial cells uniquely downregulated in pSS patients were involved in regeneration, stem cell population maintenance, cell division, and epithelial cell proliferation. This indicated an impaired stem cell property and regeneration capacity of myoepithelial cells in the SG of pSS patients which may result in the reduction of normal epithelial cells differentiation and proliferation. Our results identified three distinct endothelial subtypes according to the differentially expressed cell markers. ACKR1+ endothelial cells were expanded in the SG of pSS patients which may enhance Leukocyte transendothelial migration. A clear interferon response was observed in most celltypes. We also found a significantly expand PD-1hiCXCR5–CD4+T peripheral helper (Tph), GZMK+CD8+ T cells and a patient-specific fibroblasts in pSS patients. Cellular interaction analysis of SG revealed a strong interaction between epithelial cells and immune cells from pSS patients through CD74-MIF, MIF-TNFRSF14 and HLA-C-FAM3C receptor/ ligand pairs. Chemokine receptors CXCR4 were broadly expressed in SG immune cells implying a potentially central role in cell trafficking.

Conclusion

This resource provides deeper insights into pSS salivary glands immune microenvironment that will be helpful in understanding of the disease heterogeneity and advancing pSS therapy.

Disclosure of Interests

None declared

Dual Functions of MDP Monomer with De- and Remineralizing Ability

Methacryloyloxydecyl dihydrogen phosphate (MDP) has been speculated to induce mineralization, but there has been no convincing evidence of its ability to induce intrafibrillar mineralization. Polymers play a critical role in biomimetic mineralization as stabilizers/inducers of amorphous precursors. Hence, MDP-induced biomimetic mineralization without polymer additives has not been fully verified or elucidated. By combining 3-dimensional stochastic optical reconstruction microscopy, surface zeta potentials, contact angle measurements, inductively coupled plasma-optical emission spectroscopy, transmission electron microscopy, atomic force microscopy, and Fourier transform infrared spectroscopy with circular dichroism, we show that amphiphilic MDP can not only demineralize dentin by releasing protons as an acidic functional monomer but also infiltrate collagen fibrils (including dentin collagen), unwind the triple helical structure by breaking hydrogen bonds, and finally immobilize within collagen. MDP-bound collagen functions as a huge collagenous phosphoprotein (HCPP), in contrast to chemical phosphorylation modifications. HCPP can induce biomimetic mineralization itself without polymer additives by alternatively attracting calcium and phosphate through electrostatic attraction. Therefore, we herein propose the dual functions of amphiphilic MDP monomer with de- and remineralizing ability. MDP in the free state can demineralize dentin substrates by releasing protons, whereas MDP in the collagen-bound state as HCPP can induce intrafibrillar mineralization. The dual functions of MDP monomer with de- and remineralization properties might create a new epoch in adhesive dentistry and preventive dentistry.

Total bone mineral density is inversely associated with stroke: a family osteoporosis cohort study in rural China

BACKGROUND

The relationship of osteoporosis and stroke is still not fully clarified. Apart from the well-known risk factors for stroke, bone mineral density (BMD) has gained more interest in recent years.

AIM

To further elucidate the relationship between BMD and stroke risk, a prospective cohort study in the Chinese rural population was conducted.

DESIGN

Retrospective analysis of a family osteoporosis cohort.

METHODS

Our subjects were selected from an osteoporosis cohort conducted in Anqing, China. All participants underwent a questionnaire assessment, clinical examinations and laboratory assessments. During the follow-up period, the number of people who had a stroke was recorded. Generalized estimating equation regression analysis was performed to determine the significance of the association between BMD and stroke.

RESULTS

A total of 17868 people were included. A two-way interaction test of sex and BMD on stroke was significant (P = 0.002). There was a significant difference in BMD and stroke morbidity in the male group (P = 0.003). When BMD was assessed as quartiles and the lowest quartile was used as reference, a significantly lower risk for stroke was observed in Q2-4. Notably, no significant difference was observed in female participants with adjusted odds ratio (P > 0.05). The P-value for interaction was calculated. The body mass index (P = 0.014) and waist-to-hip ratio (P = 0.027) were found to be significantly associated with BMD and stroke risk in female participants.

CONCLUSIONS

In Chinese rural areas, total BMD may negatively correlated with stroke, especially in men.

Treatment-related adverse events as predictive biomarkers of efficacy in patients with advanced neuroendocrine tumors treated with surufatinib: results from two phase III studies

Background

No validated biomarkers currently exist for predicting the efficacy outcomes in patients with neuroendocrine tumors (NETs) treated with antiangiogenic therapy. We aimed to evaluate the association between treatment-related adverse events (TRAEs) and efficacy outcomes of surufatinib in patients with advanced NET.

Patients and methods

We included patients with NET treated with surufatinib in two multicenter, randomized, double-blind, placebo-controlled, phase III trials (SANET-p and SANET-ep) in this study. The main exposure was the presence of any of the TRAEs including hypertension, proteinuria, and hemorrhage in the first 4 weeks of surufatinib treatment. The primary outcome of the study was investigator-assessed progression-free survival (PFS). PFS outcomes were estimated using the Kaplan–Meier method with the log-rank test. Hazard ratios (HRs) were calculated by using univariable and multivariable Cox proportional hazard regression models. Blinded independent image review committee (BIIRC) assessments and 4-week landmark analysis were also performed as supportive evaluations.

Results

During the study period, a total of 242 patients treated with surufatinib were included in the analysis, and 164 (68%) patients had at least one of hypertension, proteinuria, and hemorrhage in the first 4 weeks of treatment. The presence of TRAEs in the first 4 weeks was associated with prolonged median PFS [11.1 versus 9.2 months; HR 0.67, 95% confidence interval (CI) 0.47-0.97; P = 0.036]. In multivariable Cox regression analysis, the presence of TRAEs was also significantly associated with longer PFS (HR 0.65, 95% CI 0.44-0.97; P = 0.035). Similar results were obtained in the BIIRC assessments and 4-week landmark analysis.

Conclusions

Treatment-related hypertension, proteinuria, and hemorrhage could be potential biomarkers to predict antitumor efficacy of surufatinib in patients with advanced NET. Future prospective studies are needed to validate the findings.

Trial registration

ClinicalTrials.govNCT02589821; https://clinicaltrials.gov/ct2/show/NCT02589821 and ClinicalTrials.gov NCT02588170; https://clinicaltrials.gov/ct2/show/NCT02588170

•

Treatment-related hypertension, proteinuria, or hemorrhage is associated with longer survival in NETs.

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The association is confirmed by the BIIRC assessments and 4-week landmark analysis.

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TRAEs can be biomarkers to predict antitumor efficacy in patients with NET.

[Initial clinical experience of left bundle branch pacing after transcatheter aortic valve implantation]

Objective: To investigate the efficacy and safety of left bundle branch pacing(LBBP) in patients after transcatheter aortic valve implantation (TAVI). Methods: This is a retrospective study. A total of 35 patients underwent TAVI and received pacemaker implantation from January 2018 to December 2020 in Beijing Fuwai Hospital were enrolled. Patients were divided into LBBP group (n=12) and right ventricular apex pacing (RVAP) group (n=23) according to the pacing position. The success rate of operation in LBBP group was calculated, and the occurrence of complications were observed, and the parameters of pacemaker were measured on the 3rd day and 1, 3 and 6 months after operation. The N-terminal pro-B-type natriuretic peptide (NT-proBNP), echocardiographic and ECG indexes were compared between the two groups on the 3rd day and 1, 3, and 6 months after pacemaker implantation. Result: A total of 35 patients were included, The age was (76.4±7.7) years, including 19 males (54.3%). The procedure time ((86.58±17.10)min vs. (68.74±9.18)min, P<0.001) and fluoroscopy duration ((20.08±4.44)min vs. (17.00±2.26)min, P<0.001) were significantly longer in LBBP group compared with RVAP group. The operation success rate of LBBP group was 11/12. There was no serious operation related complications such as pneumothorax, hemothorax, electrode dislocation, infection, and lower limb bleeding. The patients were followed up for 7.43 (5.21, 9.84) months. The programmed parameters of pacemaker were in the ideal range and stable during follow-up. At 3 and 6 months after operation, the left ventricular ejection fraction in LBBP group was higher than that in RVAP Group (at 3 months: (60.75±2.89)% vs. (57.35±3.33)%, P=0.004; at 6 months: (63.17±3.33)% vs. (56.17±3.97)%, P<0.001), NT-proBNP values was lower in LBBP group than that in RVAP Group (at 3 months: 822 (607, 1 150)ng/L vs. 1 052 (902, 1 536)ng/L, P=0.006; at 6 months: 440 (330,679)ng/L vs. 783 (588, 1 023)ng/L, P=0.001). At 1, 3 and 6 months after operation, the QRS duration was shorter in LBBP group than that in RVAP group (1 month: 99 (97, 107)ms vs. 126(124, 130)ms, P<0.001; 3 months: 98(96, 105)ms vs. 129(128, 133)ms, P<0.001; 6 months: 96(94, 104)ms vs. 130(128, 132)ms, P<0.001). Conclusions: For patients with permanent pacemaker indications after TAVI, LBBP is feasible, safe and reliable. It could improve the cardiac function in the short term, the long-term effect of LBBP needs to be further observed.

Digital guides to facilitate retained root removal and simultaneous implant placement

The aim of this study was to report the use of digital guides to locate impacted residual roots (IRR) (location guide) and to simultaneously insert dental implants (surgical guide). This case series included five patients. The IRR was first removed through a lateral window approach using the digital location guide, then the implant was placed simultaneously with the implant surgical guide. Definitive restorations were completed after a 6-month healing period. An average of 13.0 ± 3.1 minutes was required to locate the IRR. The implant stability quotient (ISQ) was obtained during surgery and before digital coping using a non-invasive resonance frequency measurement. The average ISQ during surgery for the five dental implants was 60.2 ± 6.3, and the value increased to 66.6 ± 4.8 before final restoration. The average deviations at the implant neck and root apex were 0.48 ± 0.25 mm and 0.74 ± 0.46 mm, respectively. The average angular deviation was 3.5 ± 1.4°. Bone resorption at the implant neck was a mean 0.072 ± 0.041 mm before final restoration. All implants functioned well at 1 year after final restoration. The application of surgical guides in the extraction of IRR enabled crestal bone preservation and simultaneous implant placement.

RNA interference in Pardosa pseudoannulata, an important predatory enemy against several insect pests, through ingestion of dsRNA-expressing Escherichia coli

RNA interference is an important technology for gene functional research in many organisms. The pond wolf spider (Pardosa pseudoannulata) is an important natural enemy of rice field pests. To facilitate large-scale gene functional research in this spider species and others, we developed an RNA interference (RNAi) method via ingestion of bacteria expressing dsRNA. The dsRNA targeting a cytochrome P450 monooxygenase (cyp41g2) was expressed in Escherichia coli HT115 (DE3). And then the bacterial suspension was fed to 14-20 days old spiderlings. The mRNA abundance of the target gene was significantly reduced after 3-day's ingestion of bacteria expressing dsRNA, and between day 5 and 7, RNAi efficiency remained stable. Thus, we selected 5 days as the optimum interference time. Furthermore, the bacteria resuspension containing 20 ng/μl dsRNA was selected as the optimum concentration. To evaluate the applicability of this method, three other genes with different tissue expression pattern were also selected as targets. And the mRNA abundance of all the four target genes was significantly reduced with RNAi efficiency between 66.0% and up to 86.9%. The results demonstrated that the oral delivery of bacteria expressing dsRNA would be an effective RNAi method for the gene functional study in P. pseudoannulata.

[Mage-D1 binding to activated p75NTR positively regulates mineralization of rat ectomesenchymal stem cells in vitro]

OBJECTIVE

To detect the binding of Mage-D1 with activated p75NTR and explore their role in regulating mineralization of ectomesenchymal stem cells (EMSCs).

METHODS

EMSCs were isolated from the tooth germs of embryonic SD rats (19.5 days of gestation) by tissue explant culture and were identified for surface markers using flow cytometry. The cultured cells were divided into blank control group, 100 ng/mL nerve growth factor (NGF) stimulation group, and lentivirus-mediated Mage-D1 interference (SH-Mage-D1) group. Proximity ligation assay was used to detect the binding of Mage-D1 with activated p75NTR in the EMSCs, and the binding strength was compared among the 3 groups. Alizarin red staining and ALP staining were used to observe mineralization of the induced cells. The expressions of ALP, Runx2, OCN, BSP, OPN, Msx1 and Dlx1 at both the mRNA and protein levels were detected using RT-PCR and Western blotting.

RESULTS

The isolated EMSCs expressed high levels of cell surface markers CD44, CD90, CD29, CD146, and CD105 with a low expression of CD45. The results of proximity ligation assay showed that the binding of Mage-D1 with activated p75NTR in the cells increased over time, and the binding strength was significantly greater in NFG-treated cells than in the cells in the other two groups (P < 0.05). Alizarin red staining and ALP staining of the induced cells showed that the changes in the mineralization nodules were consistent with those of ALP activity. The cells treated with 100 ng/mL NGF exhibited significantly increased expressions of ALP, Runx2, OCN, BSP, OPN, Col1, Msx1 and Dlx1 as compared with the cells in the other two groups (P < 0.05).

CONCLUSION

Mage-D1 directly binds to activated p75NTR in embryonic rat EMSCs to positively regulate the mineralization of the EMSCs.

[Activation of mir-30a-wnt/β-catenin signaling pathway upregulates cathepsin K expression to promote cementogenic differentiation of periodontal ligament stem cells]

OBJECTIVE

To explore the role of cathepsin K (CTSK) regulated by mir-30a-wnt/β-catenin signaling pathway in cementogenic differentiation of periodontal ligament stem cells (PDLSCs).

METHODS

Human PDLSCs isolated by limiting dilution culture were induced by enamel matrix protein derivative (EMD) for differentiation into cementoblast-like cells. MicroRNA chip technique was employed to screen the differentially expressed microRNAs in the cells during induced differentiation. The effect of inhibiting miR-30a on CTSK expression in the induced cells was examined using RT-PCR and Western blotting. Ceramic scaffolds coated with PDLSCs treated with EMD and transfected with the miR-30a inhibitor or a lentiviral vector for CTSK overexpression were prepared and implanted subcutaneously in nude mice, and 8 weeks later the cellular expressions of cementoblast markers CAP and CEMP-1 were detected with immunohistochemistry to verify whether CTSK participate in cementogenic differentiation of PDLSCs. The role of wnt signaling pathway in miR-30a-mediated regulation of CTSK expression was explored by examining CTSK protein expressions after blocking wnt signaling in PDLSCs.

RESULTS

In PDLSCs with EMD-induced differentiation into cementoblast-like cells, multiple microRNAs exhibited differential expressions; and among them, miR-30a was specifically and significantly up-regulated (P < 0.05). Up-regulation of miR-30a obviously increased the expression of CTSK (P < 0.05) and promoted PDLSCs to form cementum-like tissues with high expressions of CAP and CEMP-1. The regulatory effect of miR-30a on CTSK expression was obviously attenuated after inhibiting wnt/β-catenin signaling pathway.

CONCLUSION

EMD induces cementogenic differentiation of PDLSCs possibly by up-regulating the expression of miR-30a, which further activates the wnt/β-catenin signaling pathway to enhance the expression of CTSK.

Erythrocytes induce vascular dysfunction in COVID-19

Background

Vascular injury has been implicated as a major cause of clinical complications in patients with coronavirus disease 2019 (COVID-19). Autopsy studies have revealed destruction of the endothelial cell lining, which might explain cardiovascular alterations arising from the infection. However, data demonstrating endothelial dysfunction during ongoing infection are sparse, and the underlying mechanisms are still largely unknown. Red blood cells (RBCs) are affected by COVID-19 with alterations in their structure and function, possibly contributing to vascular injury via increased oxidative stress.

Purpose

To determine the presence of endothelial dysfunction in patients with COVID-19 and to explore the RBC as a possible mediator of such dysfunction.

Methods

The study was performed on 17 patients hospitalized for moderate COVID-19 infection and age- and sex-matched healthy subjects. Inclusion criteria of the COVID-19 patients were PCR-verified SARS-CoV2 infection, pulmonary infiltrates on x-ray, oxygen demand during hospital stay and ≤ one cardiovascular co-morbidity. Microvascular endothelial function in vivo was assessed with a pulse amplitude tonometry device on each index finger at baseline and during reactive hyperemia and expressed as reactive hyperemia index (RHI). RBCs from COVID-19 patients (C19-RBCs) and healthy subjects (H-RBCs) were incubated with isolated rat aortic segments for evaluation of endothelium-dependent and -independent relaxation.

Results

COVID-19 patients displayed profound impairment in endothelial function in vivo with RHI 1.56 (1.30–1.81, median and interquartile range) compared to healthy subjects 2.36 (1.97–2.79, p&lt;0.001). C19-RBCs induced severe impairment in both endothelium-dependent (27% maximal relaxation) and -independent relaxations (54%) compared to H-RBCs (67% and 95% relaxation, respectively). Further, C19-RBCs induced upregulation of vascular arginase 1 (∼2 fold increase compared to H-RBCs) and markers of oxidative stress (∼6 fold). Consequently, inhibition of vascular arginase or superoxide attenuated the impairment in endothelial function induced by C19-RBCs. C19-RBCs were characterized by increased production of reactive oxygen species (∼1.4 fold) and reduced export of the nitric oxide metabolite nitrate. Following pre-incubation with interferon-γ, but not interleukin-6 or tumor necrosis factor-α, H-RBCs induced impairment in endothelial function.

Conclusions

This study demonstrates the presence of marked endothelial dysfunction in an otherwise mainly healthy patient group hospitalized for COVID-19, and clearly implicates a central role of the RBC as a mediator of endothelial injury through enhancement of reactive oxygen species and arginase. These data shed light on a new pathological mechanism underlying vascular dysfunction in COVID-19 patients and may lay the foundation for future therapeutic developments.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swedish Heart and Lung foundationSwedish Research Council

Attenuated cardiac post-ischemic injury and endothelial dysfunction by stimulation of soluble guanylyl cyclase in red blood cells from patients with type 2 diabetes

Background

Reduced bioavailability of nitric oxide (NO) contributes to ischemic heart disease in type 2 diabetes (T2D). Red blood cells (RBCs) are known to produce NO bioactivity and to contain a functional soluble guanylyl cyclase (sGC) that is activated by NO. Recent studies revealed that RBCs from patients with T2D exacerbates ischemia-reperfusion (I/R) injury and induces endothelial dysfunction via a mechanism that is dependent on reduced export of NO bioactivity from RBCs. It remains unknown whether stimulation of sGC in RBCs from patients with T2D protects against myocardial I/R injury and endothelial dysfunction.

Purpose

To test the hypothesis that stimulation of sGC in RBCs from T2D patients protects against myocardial I/R injury and improves endothelial function.

Methods

RBCs collected from T2D patients and healthy subjects were incubated with vehicle or the sGC stimulator CYR715 before being administered to isolated Langendorff-perfused rat hearts subjected to 25 min global ischemia and 60 min reperfusion. Left ventricular developed pressure (LVDP) and infarct size were determined. In addition, isolated rat aortic rings were incubated with RBCs subsequent determination of endothelium-dependent relaxation (EDR).

Results

Administration of RBCs from T2D patients impaired post-ischemic recovery of LVDP and induced endothelial dysfunction in comparison with RBCs from healthy subjects (P&lt;0.001). Pre-incubation of RBCs from patients with T2D with CYR715 prior to administration to the isolated heart enhanced the recovery of LVDP (Fig.1A), reduced infarct size (Fig.1B), and attenuated endothelial dysfunction (Fig.1C). CYR715 did not induce cardioprotection in the absence of RBCs. The sGC inhibitor ODQ did not significantly affect cardiac recovery per se but totally abolished the protective effect of CYR715 (Fig.1A).

Conclusions

Stimulation of sGC in RBCs from patients with T2D protects against cardiac I/R injury and prevents development of endothelial dysfunction. Stimulation of the NO-sGC pathway in RBCs appears to be an attractive therapeutic strategy to prevent cardiovascular injury in T2D.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swedish Heart and Lung Foundation, the Swedish Research Council

Soft-Dielectron Excess in Proton-Proton Collisions at sqrt[s]=13 TeV

A measurement of dielectron production in proton-proton (pp) collisions at sqrt[s]=13  TeV, recorded with the ALICE detector at the CERN LHC, is presented in this Letter. The data set was recorded with a reduced magnetic solenoid field. This enables the investigation of a kinematic domain at low dielectron (ee) invariant mass m_{ee} and pair transverse momentum p_{T,ee} that was previously inaccessible at the LHC. The cross section for dielectron production is studied as a function of m_{ee}, p_{T,ee}, and event multiplicity dN_{ch}/dη. The expected dielectron rate from hadron decays, called hadronic cocktail, utilizes a parametrization of the measured η/π^{0} ratio in pp and proton-nucleus collisions, assuming that this ratio shows no strong dependence on collision energy at low transverse momentum. Comparison of the measured dielectron yield to the hadronic cocktail at 0.15<m_{ee}<0.6  GeV/c^{2} and for p_{T,ee}<0.4  GeV/c indicates an enhancement of soft dielectrons, reminiscent of the "anomalous" soft-photon and soft-dilepton excess in hadron-hadron collisions reported by several experiments under different experimental conditions. The enhancement factor over the hadronic cocktail amounts to 1.61±0.13(stat)±0.17(syst,data)±0.34(syst,cocktail) in the ALICE acceptance. Acceptance-corrected excess spectra in m_{ee} and p_{T,ee} are extracted and compared with calculations of dielectron production from hadronic bremsstrahlung and thermal radiation within a hadronic many-body approach.

Characterization of serum adiponectin and leptin in healthy perinatal dairy cows or cows with ketosis, and their effectson ketosis involved indices

We investigated changes in concentrations of ADP (adiponectin), LEP (leptin), BHBA (beta-hydroxybutyric acid), NEFA (non-esterified fatty acid), Glucose (Glu) and INS (insulin) in serum of healthy perinatal dairy cows and cows with ketosis. Twenty-one healthy cows and seventeen cows with ketosis from a herd of a total 60 Holstein cows (near dry period i.e. 56 days antepartum) were selected. Blood was collected through the tail vein every 7 days, from 56 day antepartum to 56 day postpartum. Serum ADP, LEP, BHBA, NEFA, Glu, and INS concentrations were determined, and ketosis was diagnosed through serum BHBA (≥1.2 mmol/L). We showed the concentration of serum adipokines and energy balancing indices were stable during antepar- tum period. However, ADP concentration increased while LEP decreased, and there were a significant increase in cows with ketosis compared to that of in healthy cows. Serum BHBA and NEFA concentrations increased significantly at first, and then gradually decreased in both healthy cows and cows with ketosis. However, cows with ketosis showed higher concentrations of BHBA and NEFA which restored later. The serum concentration of Glu in both healthy dairy cows and cows with ketosis showed a decreasing trend. INS concentration in healthy cows was decreased while it was increased in cows with ketosis. The results reflect the extent of hypo- glycemia and lipid mobilization postpartum, suggest IR exists in cows with ketosis while serum ADP and LEP might play roles in the development of ketosis.

Selective optogenetic stimulation of glutamatergic, but not GABAergic, vestibular nuclei neurons induces immediate and reversible postural imbalance in mice

Glutamatergic and GABAergic neurons represent the neural components of the medial vestibular nuclei. We assessed the functional role of glutamatergic and GABAergic neuronal pathways arising from the vestibular nuclei (VN) in the maintenance of gait and balance by optogenetically stimulating the VN in VGluT2-cre and GAD2-cre mice. We demonstrate that glutamatergic, but not GABAergic VN neuronal subpopulation is responsible for immediate and strong posturo-locomotor deficits, comparable to unilateral vestibular deafferentation models. During optogenetic stimulation, the support surface dramatically increased in VN^VGluT2+ mice, and rapidly fell back to baseline after stimulation, whilst it remained unchanged during similar stimulation of VN^GAD2+ mice. This effect persisted when vestibular tactilo kinesthesic plantar inputs were removed. Posturo-locomotor alterations evoked in VN^VGluT2+ animals were still present immediately after stimulation, while they disappeared 1 h later. Overall, these results indicate a fundamental role for VN^VGluT2+ neurons in balance and posturo-locomotor functions, but not for VN^GAD2+ neurons, in this specific context. This new optogenetic approach will be useful to characterize the role of the different VN neuronal populations involved in vestibular physiology and pathophysiology.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Adaptive ensemble perception tracking

Recently, tracking models based on bounding box regression (such as region proposal networks), built on the Siamese network, have attracted much attention. Despite their promising performance, these trackers are less effective in perceiving the target information in the following two aspects. First, existing regression models cannot take a global view of a large-scale target since the effective receptive field of a neuron is too small to cover the target with a large scale. Second, the neurons with a fixed receptive field (RF) size in these models cannot adapt to the scale and aspect ratio changes of the target. In this paper, we propose an adaptive ensemble perception tracking framework to address these issues. Specifically, we first construct a per-pixel prediction model, which predicts the target state at each pixel of the correlated feature. On top of the per-pixel prediction model, we then develop a confidence-guided ensemble prediction mechanism. The ensemble mechanism adaptively fuses the predictions of multiple pixels with the guidance of confidence maps, which enlarges the perception range and enhances the adaptive perception ability at the object-level. In addition, we introduce a receptive field adaption model to enhance the adaptive perception ability at the neuron-level, which adjusts the RF by adaptively integrating the features with different RFs. Extensive experimental results on the VOT2018, VOT2016, UAV123, LaSOT, and TC128 datasets demonstrate that the proposed algorithm performs favorably against the state-of-the-art methods in terms of accuracy and speed.

POS0280 ASSOCIATION OF COMPLEMENTARY AND ALTERNATIVE MEDICINE USE WITH KNEE SYMPTOMS AND KNEE STRUCTURAL CHANGES OVER 2.6 YEARS: A POPULATION-BASED COHORT STUDY OF TASMANIAN OLDER ADULTS

Background:

There is increasing use of complementary and alternative medicines (CAMs) alone or as an adjuvant therapy to conventional palliative medicines.1 However, there remains clinical uncertainty about the benefit of CAMs in the management of osteoarthritis in older population.

Objectives:

To describe the association between CAM use (alone or in combination with conventional analgesics) with knee symptoms and structural changes amongst a representative sample of Tasmanian older adults.

Methods:

A total of 1,099 participants were selected from the Tasmania Older Adult Cohort Study (TASOAC), an ongoing prospective population-based study. Exposure to CAM and conventional medications was classified into four categories according to the national drug code directory: 2 CAM only, conventional analgesics only, both CAM and conventional analgesics, and neither CAMs nor conventional analgesics. Knee pain was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and a 1.5-T MRI of the right knee was performed at baseline and follow-up (around 2.6 years). Longitudinal associations were assessed using mixed effect linear models.

Results:

At baseline, participants‘ mean age was 63, 86.5% (n=951) reported any medication use. The prevalence of CAM use was 35.0% and of conventional analgesics was 58.6%. Over follow-up, the analgesic only group had a significant increase in WOMAC pain, function, and stiffness scores compared to those who took neither CAMs nor conventional analgesics. There was a statistically significant femoral cartilage volume loss across all four groups, and no statistical difference was found between participants who takes both CAMs and analgesics group and the reference group, but participant in the CAM only or the analgesics only groups loss statistically significant more femoral cartilage volume than the reference group (Table 1).

Table 1.

Association of change in clinical knee symptoms and knee structural changes over 2.6 years with different medications groups.

Mean change for reference group*Change for each category, coefficient (95% confident intervals)CAMsBothAnalgesicsReference group*No. of participants327128257387327WOMAC pain (5-50)-0.95 (-1.42, -0.48)0.04 (-0.85, 0.93)0.32 (-0.4, 1.04)0.78 (0.13, 1.43)RefWOMAC function (17-170)-3.09 (-4.52, -1.67)1.02 (-1.7, 3.73)1.39 (-0.81, 3.59)2.32 (0.33, 4.31)RefWOMAC stiffness (2-20)-0.39 (-0.62, -0.17)0.15 (-0.28, 0.58)0.35 (0, 0.7)0.40 (0.09, 0.72)RefFemoral cartilage volume (mL)-187.98 (-228.79, -147.18)-113.81 (-192.60, -35.03)-1.92 (-65.00, 61.17)-127.19 (-186.31, -68.06)Ref

*Reference group=participants taken neither CAMs nor conventional analgesics

Conclusion:

CAM use alone or in combination with conventional analgesics may associate with slower progression of knee pain. Conclusive evidence on the longitudinal benefits of CAM in the management of osteoarthritis among older adults warrants more studies.

References:

[1]Steel A, McIntyre E, Harnett J, et al. Complementary medicine use in the Australian population: Results of a nationally-representative cross-sectional survey. Sci Rep 2018;8:17325.

[2]National Center for Health Statistics. Long-term Care Drug Database System: Drugs by NDC Class Code, Drug Code and Name 2007 Available from: https://www.cdc.gov/nchs/data/nnhsd/DrugsbyNDCClass3.pdf [accessed date: 2020 23 December].

The data were fitted using mixed effect linear models, which were constructed by entering baseline medication group, phase, the interaction between medication group and phase, covariates (baseline age, sex, body mass index [BMI], baseline value of outcome), the interaction between the covariates and phase, random intercept, and random slope on phase (time).

Disclosure of Interests:

None declared

[Left ventricular guidewire pacing during transcatheter aortic valve replacement]

Objective: To investigate the safety and efficacy of left ventricular guidewire pacing during transcatheter aortic valve replacement (TAVR). Methods: This is a retrospective study. Thirteen patients, who underwent TAVR with left ventricular guidewire pacing from October 2019 to December 2019 in Fuwai Hospital, were included. Clinical data and operational procedure data of the patients were collected. Changes in blood pressure and electrocardiogram were observed during operations. Ascending aorta angiography was performed to evaluate the regurgitation of aortic valve after valve implantion. The incidence of major adverse cardiac events during hospitalization and at 3-months after discharge was recorded. Results: There were 7 male and 6 female patients in this cohort,and age was (73.8±8.3) years old. Among the 13 patients, 9 were tricuspid aortic valves, 3 were bicuspid aortic valves, and 1 was degenerated bioprosthetic surgical aortic valve. TAVR were successfully performed in all of the 13 cases using pacing through the left ventricular guidewire. During balloon dilation, the blood pressure decreased to below 60 mmHg (1 mmHg=0.133 kPa) after 180 beats/min pacing, and the valve release process was smooth and the position was stable. The results of aortography showed that there was no regurgitation in 7 cases, mild regurgitation in 5 cases and moderate regurgitation in 1 case. Three patients required temporary pacing during the procedure due to complete heart block, among whom 1 patient was implanted with permanent pacemaker during hospitalization, and the other 2 patients recovered within 24 hours after operation. In another case, there was no significant change of electrocardiogram during the operation, and complete heart block occurred 10 days after the operation, and treated with permanent pacemaker. The other 10 patients began to carry out bedside activities and rehabilitation training 24 hours after operation. There was no death, myocardial infarction, stroke and other major adverse cardiac events during hospitalization and at 3-month follow-up after discharge. Conclusion: Left ventricular guidewire pacing is a safe and effective strategy for TAVR.

Deep learning analysis of the primary tumour and the prediction of lymph node metastases in gastric cancer

BACKGROUND

Lymph node metastasis (LNM) in gastric cancer is a prognostic factor and has implications for the extent of lymph node dissection. The lymphatic drainage of the stomach involves multiple nodal stations with different risks of metastases. The aim of this study was to develop a deep learning system for predicting LNMs in multiple nodal stations based on preoperative CT images in patients with gastric cancer.

METHODS

Preoperative CT images from patients who underwent gastrectomy with lymph node dissection at two medical centres were analysed retrospectively. Using a discovery patient cohort, a system of deep convolutional neural networks was developed to predict pathologically confirmed LNMs at 11 regional nodal stations. To gain understanding about the networks' prediction ability, gradient-weighted class activation mapping for visualization was assessed. The performance was tested in an external cohort of patients by analysis of area under the receiver operating characteristic (ROC) curves (AUC), sensitivity and specificity.

RESULTS

The discovery and external cohorts included 1172 and 527 patients respectively. The deep learning system demonstrated excellent prediction accuracy in the external validation cohort, with a median AUC of 0·876 (range 0·856-0·893), sensitivity of 0·743 (0·551-0·859) and specificity of 0·936 (0·672-0·966) for 11 nodal stations. The imaging models substantially outperformed clinicopathological variables for predicting LNMs (median AUC 0·652, range 0·571-0·763). By visualizing nearly 19 000 subnetworks, imaging features related to intratumoral heterogeneity and the invasive front were found to be most useful for predicting LNMs.

CONCLUSION

A deep learning system for the prediction of LNMs was developed based on preoperative CT images of gastric cancer. The models require further validation but may be used to inform prognosis and guide individualized surgical treatment.

A resonance suppression method in platform style inertial reference unit via particle swarm optimization notch filter

With the development of laser communication, remote sensing imaging, and other technologies, an inertial reference unit (IRU) plays an essential part in the line-of-sight (LOS) stabilization system used for acquiring, pointing, and tracking targets. The IRU provides a stable reference beam to realize accurate LOS pointing under external disturbances. Compared with the frame style IRU, the platform style IRU (PIRU) can achieve a higher bandwidth and better precision. However, mechanical resonance is introduced by a flexure hinge inevitably in the PIRU, which affects the performance of the LOS stabilization system. In this paper, an open-loop dynamic model of PIRU is established. Identification experiments are carried out with results indicating a 28.7 dB resonance peak at 27.07 Hz in the x axis and a 30.3 dB resonance peak at 26.59 Hz in the y axis. An asymmetric notch filter is used to suppress the resonance peak to achieve a higher control bandwidth. A fitness function is designed to represent the effect of resonance suppression. A particle swarm optimization algorithm is used to search for an optimal solution of the fitness function to obtain the parameters of the asymmetric notch filter. Experimental results show that the resonance peak is reduced by 97.88% and the system bandwidth reaches 159.31 Hz.