Synthetic molecular switches driven by DNA-modifying enzymes

Taking inspiration from natural systems, in which molecular switches are ubiquitous in the biochemistry regulatory network, we aim to design and construct synthetic molecular switches driven by DNA-modifying enzymes, such as DNA polymerase and nicking endonuclease. The enzymatic treatments on our synthetic DNA constructs controllably switch ON or OFF the sticky end cohesion and in turn cascade to the structural association or disassociation. Here we showcase the concept in multiple DNA nanostructure systems with robust assembly/disassembly performance. The switch mechanisms are first illustrated in minimalist systems with a few DNA strands. Then the ON/OFF switches are realized in complex DNA lattice and origami systems with designated morphological changes responsive to the specific enzymatic treatments.

Active learning prediction and experimental confirmation of atomic structure and thermophysical properties for liquid Hf_{76}W_{24} refractory alloy

The determination of liquid atomic structure and thermophysical properties is essential for investigating the physical characteristics and phase transitions of refractory alloys. However, due to the stringent experimental requirements and underdeveloped interatomic potentials, acquiring such information through experimentation or simulation remains challenging. Here, an active learning method incorporating a deep neural network was established to generate the interatomic potential of the Hf_{76}W_{24} refractory alloy. Then the achieved potential was applied to investigate the liquid atomic structure and thermophysical properties of this alloy over a wide temperature range. The simulation results revealed the distinctive bonding preferences among atoms, that is, Hf atoms exhibited a strong tendency for conspecific bonding, while W atoms preferred to form an interspecific bonding. The analysis of short-range order (SRO) in the liquid alloy revealed a significant proportion of icosahedral (ICO) and distorted ICO structures, which even exceeded 30% in the undercooled state. As temperature decreased, SRO structures demonstrated an increase in larger coordination number (CN) clusters and a decrease in smaller CNs. The alterations of the atomic structure indicated that the liquid alloy becomes more ordered, densely packed, and energetically favorable with decreasing temperature, consistent with the obtained fact: Both density and surface tension increase linearly. The simulated thermophysical properties were close to experimental values with minor deviations of 2.8% for density and 3.4% for surface tension. The consistency of the thermophysical properties further attested to the accuracy and reliability of active learning simulation.

Impacts of pregnancy and menopause on COVID-19 severity: a systematic review and meta-analysis of 4.6 million women

BACKGROUND

Corona Virus Disease 2019 (COVID-19) pandemic is still a public health emergency of international concern. However, whether pregnancy and menopause impact the severity of COVID-19 remain unclear.

AIM

This study is performed to investigate the truth.

DESIGN

Study appraisal and synthesis follows PRISMA guideline. Meta-analysis is performed in random-effects model.

METHODS

PubMed, Embase, Cochrane database, Central, CINAHL, ClinicalTrials.gov, WHO COVID-19 database and WHO-ICTRP are searched until 28 March 2023.

RESULTS

In total, 57 studies (4 640 275 COVID-19 women) were analyzed. Pregnant women were at a lower risk of severe COVID-19, intensive care unit (ICU) admission and disease mortality compared to those nonpregnant women with comparable comorbidities. In contrast, pregnant women with more prepregnancy comorbidities were at a higher risk of severe COVID-19, ICU admission and invasive mechanical ventilation (IMV). In addition, pregnant women with pregnancy complications had a significantly increased risk of severe COVID-19 and ICU admission. Menopause increased COVID-19 severity, IMV requirement and disease mortality. Hormone replacement therapy inhibited COVID-19 severity in postmenopausal women. Premenopausal and postmenopausal women had a lower chance of severe illness than age-matched men. The impact of pregnancy on COVID-19 severity was significant in Americans and Caucasians, whereas the effect of menopause on COVID-19 severity was only significant in Chinese.

CONCLUSIONS

Pregnancy and menopause are protective and risk factors for severe COVID-19, respectively. The protective role of pregnancy on COVID-19 is minimal and could be counteracted or masked by prepregnancy or pregnancy comorbidities. The administration of estrogen and progesterone may prevent severe COVID-19.

Mass spectrometry-based metabolic profiling for identification of biomarkers related to footpad dermatitis in ducks

1. A new assessment method for duck footpad dermatitis (FPD) evaluation was developed, combining visual and histological characters using the images and sections of 400 ducks' feet at 340 d of age. All ducks were graded as G0 (healthy), G1 (mild), G2 (moderate) and G3 (severe) according to the degree of FPD.2. To reveal the potential biomarkers in serum related to duck FPD, non-targeted metabolomics and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were used to explore differential metabolites in each group.3. There were 57, 91 and 210 annotated differential metabolites in groups G1, G2 and G3 compared with G0, which meant that the severity of FPD increased in line with the number of metabolites. Four metabolites, L-phenylalanine, L-arginine, L-leucine and L-lysine, were considered potential biomarkers related to FPD.4. KEGG enrichment analysis showed that the FPD was mainly involved in glycolysis, the tricarboxylic acid (TCA) cycle, the pentose phosphate pathway and amino acid metabolism. These are related to production metabolism and can affect the physiological activities of ducks, which might explain the decrease in production performance.

Enzymatic Assembly of DNA Nanostructures and Fragments with Sequence Overlaps

Homologous recombination, an evolutionarily conserved DNA double-strand break repair pathway to protect genome stability, has long been exploited for the in vivo and in vitro assembly of multiple DNA duplex fragments in molecular cloning. Whether such methods can also be applied in the self-assembly of DNA nanostructures remains underexplored. Here, we report an enzymatic approach for the self-assembly of high-order DNA constructs with overlapping segments. In our system, a DNA polymerase with exonuclease activity was introduced to produce ssDNA overhangs for specific sticky end cohesion, and as many as 25 DNA structural units were designed to be hierarchically assembled. Using this approach, we successfully constructed a variety of high-order DNA nanostructures, including tubes and extended oligomers, from homogeneous assembly and custom multimers from heterogeneous assembly. Our strategy expands the construction toolbox of complex DNA nanostructures and highlights the potential to enhance the assembly of duplex fragments in molecular cloning.

Controllable dynamics of complex DNA nanostructures

In the past four decades, a variety of self-assembly design frameworks have led to the construction of versatile DNA nanostructures with increasing complexity and controllability. The controllable dynamics of DNA nanostructures has garnered much interest and emerged as a powerful tool for conducting sophisticated tasks at the molecular level. In this minireview, we summarized the controllable reconfigurations of complex DNA nanostructures induced by nucleic acid strands, environmental stimuli and enzymatic treatments. We also envisioned that with the optimization of response time, sensitivity and specificity, dynamic DNA nanostructures have great promise in applications ranging from nanorobotics to life sciences.

[Association of greenness exposure with waist circumference and central obesity in Chinese adults aged 65 years and over]

Objective: To examine the association of greenness exposure with waist circumference (WC) and central obesity in older adults in China. Methods: Based on the cross-sectional data from the Chinese Longitudinal Healthy Longevity Survey in 2017-2018, 14 056 participants aged 65 years and over were included. Demographic characteristics, lifestyle, WC, and other information were collected through a questionnaire and physical examination. Based on the satellite monitoring data of moderate-resolution imaging spectroradiometer (MODIS) provided by NASA, the annual mean of normalized difference vegetation index (NDVI) within a radius of 1 000 meters was obtained as the measurement value of greenness exposure. Multivariate linear regression model, multivariate logistic regression model, and restricted cubic splines (RCS) model were used to analyze the association and dose-response relationship between greenness exposure and WC and central obesity in older adults in China. Results: A total of 14 056 participants were enrolled with a median age of 84.0 years [IQR: 75.0-94.0 years]. About 45.0% (6 330) of them were male and 48.6% (5 853) were illiterate. There were 10 964 (78.0%) participants from rural. The mean of WC was (84.4±10.8) cm. Central obesity accounted for 60.2% (8 465), and the NDVI range was (-0.06, 0.78). After adjusting for confounding factors, the multivariate linear regression model showed that the change value of WC in the urban group [β (95%CI):-0.49 (-0.93, -0.06)] was smaller than that in the rural [-0.78 (-0.98, -0.58)] for every 0.1 unit increase in NDVI (Pinteraction=0.022). Compared with the Q1 group in NDVI, WC of Q2 and Q3 groups in rural decreased, and the β (95%CI) values were-1.74 (-2.5, -0.98) and-2.78 (-3.55, -2.00), respectively. The multivariate logistic regression model showed that after adjusting for confounding factors, the risk of central obesity decreased for urban and rural older adults with an increase of 0.1 unit in NDVI, and the OR (95%CI) values were 0.87 (0.80, 0.95) and 0.86 (0.82, 0.89), respectively (Pinteraction=0.284). Compared with the Q1 group in NDVI, the risk of central obesity in the Q2 and Q3 groups in rural was lower, and the OR (95%CI) values were 0.68 (0.58, 0.80) and 0.57 (0.49, 0.68), respectively. The results of the multivariate regression model with RCS showed that there was a non-linear association of NDVI with WC (Pnonlinear=0.006) and central obesity (Pnonlinear=0.025). Conclusion: Greenness exposure is negatively associated with WC and central obesity in older adults in China.

Mesojunction-Based Design Paradigm of Structural DNA Nanotechnology

Mesojunctions were introduced as a basic type of crossover configuration in the early development of structural DNA nanotechnology. However, the investigations of self-assembly from multiple mesojunction complexes have been overlooked in comparison to their counterparts based on regular junctions. In this work, we designed standardized component strands for the construction of complex mesojunction lattices. Three typical mesojunction configurations with three and four arms were showcased in the self-assembly of 1-, 2-, and 3-dimensional lattices constructed from both a scaffold-free tiling approach and a scaffolded origami approach.

[Current status and future prospects of robotic surgical system in radical gastrectomy for gastric cancer]

Robotic gastrectomy (RG) has always been a hot topic in the field of minimally invasive surgery for gastric cancer. More and more studies have confirmed that short- and long-term outcomes of RG are similar to those of laparoscopic gastrectomy. Robotic surgical systems have more advantages in specific regional lymph node dissection. More delicate operation can reduce intraoperative blood loss and the incidence of postoperative complications. Robotic surgical systems are also more ergonomically designed. However, there are also some problems such as high surgical cost, lack of tactile feedback and prolonged total operation time. In the future, robotic surgical system may be further developed in the direction of miniaturization, intelligence and modularity. At the same time, the robotic surgical system deeply integrated with artificial intelligence technology may realize the automation of some operation steps to some extent.

Design of Orthogonal DNA Sticky-End Cohesion Based on Configuration-Specific Molecular Recognition

In sticky-end cohesion, sequence complementarity is the key to design specific recognition among many DNA nanostructure units. The binding orthogonality usually arises from sticky-end pairs of different sequences. Instead of creating orthogonal species of sticky-end bonds based on sequence complementarity, we restricted the sticky-end sequence diversity down to the fixed C-G pair and explored orthogonal recognition of the synthetic DNA constructs based solely on the configurational match. From our comprehensive investigations of 2D tessellation and 3D crystallization, we demonstrated the new configuration-specific sticky-end cohesion to program specific and precise molecular recognition of synthetic structural units for high-order DNA self-assembly.

Reconfiguration of DNA nanostructures induced by enzymatic ligation treatment

Enzymatic ligation is a popular method in DNA nanotechnology for structural enforcement. When employed as stability switch for chosen components, ligation can be applied to induce DNA nanostructure reconfiguration. In this study, we investigate the reinforcement effect of ligation on addressable DNA nanostructures assembled entirely from short synthetic strands as the basis of structural reconfiguration. A careful calibration of ligation efficiency is performed on structures with programmable nicks. Systematic investigation using comparative agarose gel electrophoresis enables quantitative assessment of enhanced survivability with ligation treatment on a number of unique structures. The solid ligation performance sets up the foundation for the ligation-based structural reconfiguration. With the capability of switching base pairing status between permanent and transient (ON and OFF) by a simple round of enzymatic treatment, ligation induced reconfiguration can be engineered for DNA nanostructures accordingly.

Controllable assembly of synthetic constructs with programmable ternary DNA interaction

Compared with the dual binding components in a binary interaction, the third component of a ternary interaction often serves as modulator or regulator in biochemical processes. Here, we presented a programmable ternary interaction strategy based on the natural DNA triplex structure. With the DNA triplex-based ternary interaction, we have successfully demonstrated controllable hierarchical assemblies from nanometer scale synthetic DNA nanostructure units to micrometer scale live bacteria. A selective signaling system responsive to orthogonal nucleic acid signals via ternary interaction was also demonstrated. This assembly method could further enrich the diversified design schemes of DNA nanotechnology.

A narrative review of tissue-resident memory T cells and their role in immune surveillance and COVID-19

Most effector T cells will undergo programmed apoptosis after an immune response and some of them may become memory T cells. According to the distribution and functional status, the memory T cells can be divided into effector central memory T cells (TCM), effector memory T cells (TEM) and tissue-resident memory T cells (TRM) cells. TRM cells, including CD4+ TRM and CD8+ TRM cells, colonize various barrier surfaces and are no longer involved in lymphocyte recycling, closely monitored for local perturbations in homeostasis throughout the body as a critical component of the first defense line. When pathogenic microorganisms invade the body, TRM cells can quickly produce a defense response to initiate innate immunity and adaptive immunity by producing cytokines or killer molecules to resist viral and bacterial infections. In addition, TRM cells are also involved in cancer surveillance and play an essential role in maintaining cancer-immune equilibrium. The high frequency of TRM cells in tumor tissues often means favorable survival for patients. The latest research proves that TRM cells also play an important role in vaccine development and pathological features of COVID-19. This article will summarize the biological functions of TRM cells and aims at providing references for further research on their mechanism and for targeting the best treatment of clinical disease.

Acoustic manipulation dynamics of levitated particle with screw-shaped reflecting surface

Existing single-axis acoustic levitation devices with an axisymmetric reflector can manipulate particles in a variety of ways. However, the mechanism by which particles are suspended in a single-axis acoustic levitator with a non-axisymmetric reflector remains poorly understood. This work addresses this issue by proposing a novel single-axis ultrasonic levitator design that includes a flat plane emitter and a screw-plane reflector. The node positions of the standing wave formed in this levitator were predicted by calculating the Gor'kov potential according to a numerical model. The analysis results demonstrate that the nodes were distributed off-axis and their positions varied in a spiral manner when changing the distance between the emitter and reflector. Corresponding experiments based on the proposed design were also conducted, and the results indicated that the distance changes between the emitter and reflector could induce some spiral trajectories of a polyethylene-foam particle placed in the ultrasonic field. Moreover, the trajectory of the suspended particle was found to distribute along a conical surface centered on the central axis of this device. This work provides a new approach for ultrasonic particle manipulation by changing the geometry of the reflector.

[A nomogram for predicting lymph node metastasis in early gastric cancer]

Objective: To explore the independent risk factors of lymph node metastasis (LNM) in early gastric cancer, and to use nomogram to construct a prediction model for above LNM. Methods: A retrospective cohort study was conducted. Inclusion criteria: (1) primary early gastric cancer as stage pT1 confirmed by postoperative pathology; (2) complete clinicopathological data. Exclusion criteria: (1) patients with advanced gastric cancer, stump gastric cancer or history of gastrectomy; (2) early gastric cancer patients confirmed by pathology after neoadjuvant chemotherapy; (3) other types of gastric tumors, such as lymphoma, neuroendocrine tumor, stromal tumor, etc.; (4) primary tumors of other organs with gastric metastasis. According to the above criteria, 1633 patients with early gastric cancer who underwent radical gastrectomy at the Department of General Surgery of the Chinese PLA General Hospital First Medical Center from December 2005 to December 2020 were enrolled as training set, meanwhile 239 patients with early gastric cancer who underwent gastrectomy at the Department of General Surgery of the Chinese PLA General Hospital Fourth Medical Center from December 2015 to December 2020 were enrolled as external validation set. Risk factors of LNM in early gastric cancer were identified by using univariate and multivariate logistic regression analyses. A nomogram prediction model was established with significant factors screened by multivariate analysis. Area under the receiver operating characteristic curve (AUC) was used for assessing the predictive value of the model. Calibration curve was drawn for external validation. Results: Among 1633 patients in training set, the mean number of retrieved lymph nodes was 20 (13-28), and 209 patients (12.8%) had lymph node metastasis. Univariate analysis showed that gender, resection range, tumor location, tumor morphology, lymph node clearance, vascular invasion, lymphatic cancer thrombus, tumor length, tumor differentiation, microscopic presence of signet ring cells and depth of tumor invasion were associated with LNM (all P<0.05). Multivariate analysis revealed that females, tumor morphology as ulcer type, vascular invasion, lymphatic cancer thrombus, tumor length≥3 cm, deeper invasion of mucosa, and poor differentiation were independent risk factors for LNM in early gastric cancers (all P<0.05). Receiver operating characteristic curve indicated that AUC of training set was 0.818 (95%CI: 0.790-0.847) and AUC of external validation set was 0.765 (95%CI: 0.688-0.843). The calibration curve showed that the LNM probability predicted by nomogram was consistent with the actual situation (C-index: 0.818 in training set and 0.765 in external validation set). Conclusions: Females, tumor morphology as ulcer type, vascular invasion, lymphatic cancer thrombus, tumor length≥3 cm, deeper invasion of mucosa and poor differentiation are independent risk factors for LNM of early gastric cancer. The establishment of a nomogram prediction model for LNM in early gastric cancer has great diagnostic value and can provide reference for treatment selection.

[Analysis of influence factors for short-term recurrence of retroperitoneal liposarcoma after complete resection]

Objective: To examine the influence factors of short-term recurrence after complete surgical resection of retroperitoneal liposarcoma. Methods: The clinicopathological data of retroperitoneal liposarcoma at Department of General Surgery, the First Medical Center, People's Liberation Army General Hospital from January 1, 2000 to January 31, 2020 were retrospectively analyzed. There were 60 males and 31 females, aged (52.1±9.9) years (range: 30 to 84 years). Tumor recurrence within 12 months after complete resection was defined as short-term recurrence, and tumor recurrence more than 12 months was defined as non-short-term recurrence. The t test, rank-sum test, χ² test and Fisher exact test were conducted for inter-group comparison. Logistic regression analysis was used to analyze the independent influence factors for the short-term recurrence of retroperitoneal liposarcoma after complete resection. The Kaplan-Meier curve was used to calculate the recurrence-free survival, and the Log-rank test was adopted for the comparison between the groups. Results: The univariate analysis results showed that irregular tumor morphology, multiple pathological subtypes, pathological scores>3, and multiple primary tumors are influence factors for short-term recurrence after complete resection of retroperitoneal liposarcoma (χ²: 4.422 to 7.773, all P<0.05). Regression analysis of the above risk factors showed that multiple primary tumors was the independent risk factor (OR=2.918, 95%CI: 1.127 to 7.556, P=0.027). In the short-term recurrence group, Kaplan-Meier curve analysis showed that patients with multiple primary tumors had a shorter median recurrence time than patients with unifocal tumor (6 months vs. 9 months, P=0.028). Conclusions: Multiple primary tumor is an independent risk factor for short-term recurrence after complete resection of retroperitoneal liposarcoma. It suggests that the frequency of follow-up after surgery should be increased for such patients.

Reconfigurable Two-Dimensional DNA Lattices: Static and Dynamic Angle Control

Branched DNA motifs serve as the basic construction elements for all synthetic DNA nanostructures. However, precise control of branching orientation remains a key challenge to further heighten the overall structural order. In this study, we use two strategies to control the branching orientation. The first one is based on immobile Holliday junctions which employ specific nucleotide sequences at the branch points which dictate their orientation. The second strategy is to use angle-enforcing struts to fix the branching orientation with flexible spacers at the branch points. We have also demonstrated that the branching orientation control can be achieved dynamically, either by canonical Watson-Crick base pairing or non-canonical nucleobase interactions (e.g., i-motif and G-quadruplex). With precise angle control and feedback from the chemical environment, these results will enable novel DNA nanomechanical sensing devices, and precisely-ordered three-dimensional architectures.

Monochromatic Fluorescent Barcodes Hierarchically Assembled from Modular DNA Origami Nanorods

With the rapid advancement of fluorescence microscopy, there is a growing interest in the multiplexed detection and identification of various bioanalytes (e.g., nucleic acids and proteins) for efficient sample processing and analysis. We introduce in this work a simple and robust method to provide combinations for micrometer-scale fluorescent DNA barcodes of hierarchically assembled DNA origami superstructures for multiplexed molecular probing. In addition to optically resolvable dots, we placed fluorescent loci on adjacent origami within the diffraction limit of each other, rendering them as unresolvable bars of measurable lengths. We created a basic set of barcodes and trained a machine learning algorithm to process and identify individual barcodes from raw images with high accuracy. Moreover, we demonstrated that the number of combinations can be increased exponentially by generating longer barcodes, by controlling the number of incorporated fluorophores to create multiple levels of fluorescence intensity, and by employing super-resolution imaging. To showcase the readiness of the barcodes for applications, we used our barcodes to capture and identify target nucleic acid sequences and for simultaneous multiplexed characterization of binding kinetics of several orthogonal complementary nucleic acids.

Rational Design of Allosteric Nanodevices Based on DNA Triple Helix

Inspired by allosteric regulation of natural molecules, we present a rational design scheme to build synthetic nucleic acid allosteric nanodevices. The clearly specified conformational states of switches obtained from systematic screening and analyses make the ON-OFF transition clear-cut and quantification ready. Under the rational design scheme, we have developed a series of DNA switches with triplex-forming oligos as allosteric modulators and implemented designated allosteric transitions, allosteric coregulation, and reaction pathway control. In conjunction with toehold-mediated strand displacement, our design scheme has also been applied to synthetic nucleic acid computing including a set of logic operations and complex algorithm.

[Analysis of seven cases of multiple myeloma with initial manifestation of bleeding]

A retrospective analysis of 7 patients of multiple myeloma (MM) with initial manifestation of bleeding and coagulation abnormalities were performed. Clinical manifestations, laboratory and imaging examinations were collected. The activity of coagulation factors was measured before the treatment. Single factor X deficiency was seen in one patient. Two cases had factor Ⅶ deficiency, while four other patients had multiple factor deficiency. The time from onset of symptoms to diagnosis ranged from 2 to 10 months. After anti-MM treatment started and plasma or coagulation factors were transfused, the prolonged coagulation time returned to normal from 28-84 days. Most of these patients presented large, deep and multiple sites of hematoma, which caused concerns of bone marrow puncture and may direct to other differential diagnoses. This is helpful to improve physicians' understanding of the special clinical characteristics in MM patients.

[Evaluation of basic laparoscopic training under 5A teaching mode]

Objective: To evaluate the rationality and effectiveness of basic laparoscopic training under 5A teaching mode. Methods: A prospective randomized controlled study was conducted. The teaching records of 70 trainees who received basic laparoscopic traning at the Laparoscopic Surgical Training Base in Chinese PLA General Hospital from July to December 2019 were analyzed. All the trainees participating in the laparoscopy training had obtained the national practicing physician certificates, including 12 junior physicians of our center, 9 intermediate physicians of our center, 19 advanced physicians, 13 postgraduate students, 8 doctoral students, and 9 surgical standardized training physicians. A random number table method was used to divide all the trainees into two groups: the traditional teaching group or the 5A teaching group (35 people in each group). In the traditional teaching group, the training of 4 modules of " precise beans, quincuncial piles, ring positioning and knot-tying suture" modules according to a fixed sequence and schedule was carried out. Each module had a learning time of 8 hours. In the 5A teaching group, the training started from five dimensions of analysis, aim, accomplishment, appraise and advance. Before conducting each stage of training, the actual operation ability of the trainees was tested, each class hour was designed individually, accurate teaching was conducted to the trainees, the ability of the trainees was evaluated dynamically, and the previous steps were cycled periodically based on class hours. The operating time and pass rate of trainees of two groups in the basic operation module of laparoscopy were statistically analyzed, and a hierarchical analysis of related influencing factors was conducted. Results: The time of above modules before training in the 5A teaching group and the traditional teaching group was similar (all P>0.05). After definitive training, the time required for trainees in 5A teaching group and traditional teaching group to complete the 4 modules was shortened to varying degrees. Compared to traditional teaching group, 5A teaching group spent less time in completing each project [precise beans: (63.2±10.1) seconds vs. (83.6±18.7) seconds, quincuncial piles: (56.2±7.3) seconds vs. (101.4±31.7) seconds, ring positioning: (84.2±13.7) seconds vs. (127.3±28.5) seconds, knot-tying suture: (263.2±41.8) seconds vs.(428.8±95.2) seconds, all P<0.05], and had higher pass rates [precise beans: 97.1% (34/35) vs. 80.0% (28/35), quincuncial piles: 91.4% (32/35) vs.71.4% (25/35), ring positioning: 100.0% (35/35) vs. 82.9% (29/35), knot-tying suture: 77.1% (27/35) vs. 60.0% (21/35), all P<0.05]. Among the junior trainees (junior physicians of our center, postgraduate students, doctoral students, and standardized surgical training physicians) and intermediate trainees (intermediate physicians of our center and advanced physicians), the 5A teaching group completed 3 modules (quincuncial piles, ring positioning and knot-tying suture) faster than the traditional teaching group [junior trainees: quincuncial piles (76.4±12.4) seconds vs. (139.8±41.6) seconds, ring positioning (92.2±20.5) seconds vs. (131.3±28.4) seconds, knot-tying suture (293.8±66.7) seconds vs. (444.3±103.3) seconds; intermediate trainees: quincuncial piles (51.4±5.9) seconds vs. (94.7±8.6) seconds, ring positioning (63.9±13.5) seconds vs. (87.5±18.6) seconds, knot-tying suture (210.1±35.6) seconds vs. (367.5±54.9) seconds, all P<0.05]. Conclusion: 5A teaching mode can acheive better training results compared with the traditional teaching mode in basic laparoscopic training, and is worthy of further popularization and application.

[Effect of stable overexpression of XAF1 gene on biological characteristics of ovarian cancer A2780 cells]

OBJECTIVE

To construct an ovarian cancer cell line stably overexpressing XAF1 gene and observe the effects of XAF1 gene overexpression on proliferation, apoptosis, cell cycle and sensitivity to paclitaxel of the cells.

OBJECTIVE

Ovarian cancer A2780 cells were transfected with the plasmids pcDNA3.1(+) or pcDNA3.1(+)-XAF1, and the cells stably Over expressing XAF1 (A2780/XAF1 cells) were screened using G418. Cell clone formation assay and CCK8 assay were used to evaluate the changes in proliferation and paclitaxel sensitivity of the transfected cells, and cell cycle and apoptosis of the cells were analyzed using flow cytometry.

OBJECTIVE

We successfully obtained A2780/XAF1 cells stably overexpressing XAF1, which exhibited no significant changes in cell morphology. Compared with the negative control cells (A2780/NC), A2780/XAF1 cells had lowered clone formation ability (P=0.0016) and attenuated proliferative activity on the first (P=0.009) and third (P=0.0035) days after cell adherence with also a significantly increased percentage of cells in G2-M phase (P < 0.001). A2780/XAF1 cells showed significantly higher apoptosis rates than A2780/NC cells in the absence of apoptotic stimulation, in serum-free culture or following paclitaxel induction (P < 0.001). The proliferative activity of A2780/XAF1 cells was significantly lower than that of A2780/NC cells after exposure to different paclitaxel concentrations (P < 0.001). The half inhibitory concentration of paclitaxel was significantly lower in A2780/XAF1 than in A2780/NC cells.

OBJECTIVE

Overexpression of XAF1 significantly inhibits the proliferation, induces cell cycle arrest, promotes apoptosis, and increases paclitaxel sensitivity in ovarian cancer cells.

AB0280 THE INFLUENCE OF TARGET THERAPY AS WELL AS GLUCOCORTICOIDS TAPERING ON DISEASE FLARE IN SYSTEMIC LUPUS ERYTHEMATOSUS: RESULTS FROM A PROSPECTIVE CHINESE COHORT

Background:

Treat-to-target in systemic lupus erythematosus (SLE) has been proposed for 7 years and several recommendations were developed [1]. In these recommendations, prevention of flares should be a realistic target. Meanwhile, ‘remission’ or ‘low disease activity’ was recommended as the treatment target and minimizing glucocorticoids (GC) dose or withdrawal if possible was suggested in the maintenance treatment. However, would target therapy and GC tapering/withdrawal influence disease flare?

Objectives:

To investigate the frequency and determinants of disease flare, especially the influence of target therapy as well as GC tapering on flare in Chinese lupus patients.

Methods:

The baseline and follow-up data of all consecutive patients in a prospective longitudinal lupus cohort from January 2017 to June 2020 were collected. The lupus low disease activity state (LLDAS) was defined as in Golder et al., 2019[2]. The criteria for remission were from DORIS definitions [3]. Flare was assessed using the SELENA-SLEDAI flare index [4].

Results:

We enrolled 185 patients with disease duration at recruitment of 2.3 (0.8–7.7) years. During the 26.2 (12.5-34.5) months of follow-up, 73 (39.5%) patients experienced 95 flares, including 70 mild/moderate and 25 severe flares. The incidence of flare per patient-year was 0.27. Kaplan-Meier analyses showed that compared with those who never achieved LLDAS or DORIS, the patients who achieved the target at least once had a higher flare free survival rate; meanwhile, the patients with prednisone withdrawn had significantly lower flare free rate compared with those with small dose of GC maintained (≤7.5mg/d) (Figure 1A), but among the patients with different prednisone maintain doses (7.5~5mg, 5~2.5mg, and ≤2.5mg) there was not significant difference (Figure 1B). Cox regression analysis showed that younger age at disease onset and lower Complement 3 (C3) level at recruitment were independent risk factors for flare and achieving LLDAS or DORIS ≥50% of visits was independent protective factor (Table 1).

Conclusion:

In this Chinese prospective SLE cohort, age at disease onset, C3 level at recruitment and therapeutic target achieving influenced disease flare independently and significantly. GC tapering in appropriate patients and with appropriate pace did not increase the flare rate, but prednisone withdrawal may induce more disease exacerbation, which needs to be confirmed by large prospective studies.

References:

[1]Van Vollenhoven R F, et al. Treat-to-target in systemic lupus erythematosus: recommendations from an international task force. Ann Rheum Dis, 2014. 73(6): 958-967

[2]Golder, V., et al. Lupus low disease activity state as a treatment endpoint for systemic lupus erythematosus: a prospective validation study. The Lancet Rheumatology, 2019. 1(2): p. e95-e102.

[3]van Vollenhoven R, et al. A framework for remission in SLE: consensus findings from a large international task force on definitions of remission in SLE (DORIS). Ann Rheum Dis. 2017. 76(3): 554–561.

[4]Petri M, et al. Classification and definition of major flares in SLE clinical trials. Lupus. 1999. 8(8): 685-691.

Table 1.

Determinants of disease flare by multivariate Cox regression analyses

Model 1(LLDAS) ΔModel 2(RONT) ΔModel 3(Complete RONT) ΔHR95%CIP valueHR95%CIP valueHR95%CIP valueAge at disease onset (years)†0.970.95-0.990.0040.970.95-0.990.0030.970.95-0.990.003Anti-dsDNA positive at recruitment1.340.82-2.180.2171.120.68-1.850.6491.190.73-1.960.486C3 (mg/L) at recruitment0.9980.997-0.9990.0040.9980.997-0.9990.0070.9980.997-1.0000.010Minimum prednisone dose during follow- up (mg/d)0.980.90-1.080.7161.010.94-1.080.7471.040.97-1.110.243Therapeutic target achieved≥50% of observationsΔ0.600.39-0.940.0010.540.34-0.870.0110.680.51-0.920.011

Δ In the three hazard models, the different target achievement status were included respectively.

RONT: Clinical remission on treatment; Complete RONT: Complete remission on treatment.

Disclosure of Interests:

None declared

[A novel classification and strategy choice of digestive tract reconstruction procedures after function-preserving gastrectomy for early gastric caner]

Function-preserving gastrectomy (FPG) can be regarded as a concrete embodiment of precise treatment for early gastric cancer. Digestive tract reconstruction plays an important role in FPG. The aims of reconstruction mainly include the preservation of normal digestive tract and digestive function, the reconstruction of pivotal anatomical structure, and the consequent improvement of postoperative quality of life. We establish a new classification of digestive tract reconstruction based on the different role of digestive tract reconstructions in FPG for early gastric cancer, meanwhile we briefly summarize current progress and elucidate surgical indications. We hope that it can provide theoretical reference for surgeons to choose the appropriate procedure of digestive tract reconstruction after FPG.

[Risk factors of postoperative complication after total gastrectomy in advanced gastric cancer patients receiving neoadjuvant chemotherapy]

Objective: At present, there are few studies focusing on the factors short-term complications after total gastrectomy in patients with advanced gastric cancer receiving neoadjuvant chemotherapy (NACT). The purpose of this study is to provide a reference for clinical prevention of complications in these patients. Methods: A retrospective case-control study was conducted. Case inclusion criteria: (1) clinical stage II-III gastric cancer diagnosed by preoperative gastroscopy, pathology, abdominal CT, EUS or PET-CT; (2) evaluated suitable for NACT by MDT discussion; (3) no previous history of other malignant tumors and no concurrent tumor; (4) undergoing total gastrectomy+ D2 lymphadenectomy after NACT. Exclusion criteria: (1) age <18 or >80 years old; (2) severe concurrent diseases, and ASA classification>grade III; (3) stump gastric cancer or history of gastric surgery; (4) incomplete clinicopathological data. According to the above criteria, clinicopathological data of 140 advanced gastric cancer patients who underwent total gastrectomy after NACT in Chinese PLA General Hospital between June 2012 and June 2019 were collected, including 109 males and 31 females with mean age of (56.9±11.4) years and body mass indey (BMI) of (23.3±3.1) kg/m(2). Logistic analysis was used to analyze the relationship between postoperative complication and clinicopathological data. Factors in univariate analysis with P<0.05 were included in the multivariate analysis. Results: Postoperative complications (Clavien-Dindo classification ≥ II) occurred in 35 cases (25.0%) and severe complications (Clavien-Dindo classification ≥ IIIa) occurred in 4 cases (2.9%), including 1 case of esophago-jejunal anastomotic leakage, 1 case of vena cava thrombosis, 1 case of pleural effusion, 1 case of septic shock during perioperative days resulting in death. Univariate analysis showed that BMI (P=0.011), cycle of NACT (P=0.027), tumor diameter (P=0.021), and vascular invasion (P=0.033) were associated with postoperative complication within 30 days, while open/laparoscopic total gastrectomy were not associated with postoperative complication (P=0.926). Multivariate analysis revealed that BMI ≥ 25 kg/m(2) (OR=3.294, 95% CI: 1.343-8.079, P=0.009) and < 4 cycles of NACT (OR=2.922, 95% CI: 1.217-7.016, P=0.016) were independent risk factors for postoperative complication. The 3-year overall survival rates of patients with or without complication were 54.4% and 64.0%, respectively (P=0.395), and 3-year disease-free survival rates were 47.4% and 52.9%, respectively (P=0.587). Conclusions: Higher BMI and fewer cycles of NACT are independent risk factors of postoperative complication in advanced gastric cancer patients undergoing total gastrectomy after NACT. No obvious association is found between postoperative complication and surgical approaches.

[Analysis of clinicopathologic characteristics of gastric cancer patients undergoing gastrectomy based on a single-center gastric cancer database with above 10 000 cases]

Objective: The storage of medical data has been digitized in China, but a unified and structured model has not yet been established. The standardized collection, analysis and sorting of tumor clinical data is the foundation of improving the standard of tumor diagnosis and treatment. Therefore, establishing a database platform of gastric cancer (GC) is an urgent need to integrate data resources and improve the level of diagnosis and treatment. The population economics indexes of GC patients in the last 20 years are analyzed in a single-center GC database. The medical records were structured by natural language processing technology. Authors aim to investigate the clinical pathological characteristics, staging and survival of the GC patients with gastrectomy. Method: A retrospective cohort study was carried out. Clinicopatological data of patients receiving surgical treatment from 2000 to 2019 were retrospectively collected. According to the gastric cancer TNM staging guidelines from the Union for International Cancer Control and the American Joint Committee on Cancer (UICC/AJCC) 8th edition, the structured gastric cancer clinicopathological data were re-evaluated and interpreted. The Kaplan-Meier method and the log-rank test were used to compare survival rate among different groups of patients with complete follow-up data of 2010-2016. Results: Clinicopathological data of 13 492 GC patients were enrolled. The ratio of men to women in the whole group was 3.25:1.00, including 10 320 men with average onset age of 59.68 years, which was basically stable in recent 20 years, and 3172 women with average onset age of 55.93 years, which presented a trend of average increasement of 0.17 year per year. The average hospitalization duration for GC patients showed a decreasing trend year by year, which was 13.87 days in 2019. Average hospitalization cost for GC patients was increasing year by year, with a peak of 83 600 CNY in 2017 and 75 400 CNY in 2019. By natural language identification and exclusion criteria screening, a total of 7218 GC patients obtained structured clinicopathological information. Analysis on clinicopathological characteristics of 3626 GC patients in the last 5 years showed that the average diameter of tumor was (4.44±2.61) cm; the average number of harvested lymph node was 24.30±13.29; the proportion of surgical methods were as following: open surgery in 1398 cases (38.55%), laparoscopic surgery in 1856 cases (51.19%) and robotic surgery in 372 cases (10.26%). The postoperative pathological stage was as following: IA in 658 cases (18.15%), IB in 318 cases (8.77%), IIA in 559 cases (15.42%), IIB in 543 (14.98%), III A in 632 (17.43%), III B in 612 cases (16.88%), III C in 276 cases (7.61%), and IV in 28 cases (0.77%). Complete follow-up data of 3431 patients from 2010 to 2016 were presented. The 1-, 3- and 5-year survival rates were 82%, 69% and 60%, respectively for the whole group. The 1-, 3- and 5-year survival rates for patients undergoing laparoscopic surgery were 83%, 70% and 64%, respectively, and for those undergoing open surgery were 81%, 67% and 56%, respectively, and the difference between the two groups was not statistically significant (P=0.109). The 5-year survival rate of GC patients with different AJCC stages was as following: 88% in IA, 77% in IB, 70% in II A, 62% in II B, 44% in III A, 32% in III B, 22% in III C, and 17% in IV. Conclusion: This study provides basic data for the establishment of comprehensive diagnosis and treatment model of multicenter, shedding light on the improvement of comprehensive treatment of GC in China.

Caspofungin combined with TMP/SMZ as a first-line therapy for moderate-to-severe PCP in patients with human immunodeficiency virus infection

OBJECTIVES

The effectiveness of trimethoprim/sulfamethoxazole (TMP/SMZ) for pneumocystis pneumonia (PCP) is limited with adverse events. Caspofungin, by inhibiting the cyst form of Pneumocystis jirovecii, may be an alternative therapy for PCP. However, the availability of clinical data about caspofungin combined with TMP/SMZ in the treatment of PCP in HIV-infected patients is limited. Thus, we aimed to examine the clinical effectiveness and safety of caspofungin combined with TMP/SMZ as a first-line therapy for moderate-to-severe PCP in HIV-infected patients.

METHODS

From January 2017 to December 2019, data of HIV-infected patients with moderate-to-severe PCP who received either TMP/SMZ alone or caspofungin combined with TMP/SMZ as first-line therapy were retrospectively reviewed to assess the effectiveness and safety of each regimen. The Kaplan-Meier curve and log-rank test were used for survival analysis.

RESULTS

A total of 278 patients met the criteria. The overall positive response rate of PCP treatment was 48.92%, and the overall all-cause in-hospital mortality rate was 33.09%. Patients who received combination therapy consisting of caspofungin and TMP/SMZ had a better positive response rate (59.44% vs. 37.78%, P < 0.001) and lower all-cause in-hospital mortality rate (24.48% vs. 42.22%, P = 0.003). Also, patients who received combination therapy had higher survival rate during a hospital stay (75.52% vs. 57.78%, P = 0.004), and those who received longer combination therapy were more likely to have higher survival rate (P = 0.042). We found that age (P = 0.019), CD4 cell count (P = 0.001) and therapeutic regimen (P = 0.002) were significant risk factors for all-cause in-hospital mortality rate in univariate analysis. In multivariate analysis, only CD4 cell count and therapeutic regimen were statistically significant factors associated with all-cause in-hospital mortality rate. Patients with a CD4 count of > 30 cells/µL and patients who received combination therapy consisting of caspofungin and TMP/SMZ were more likely to survive from PCP (P = 0.011 and P = 0.002, respectively). There were no additional severe adverse events caused by adding caspofungin.

CONCLUSIONS

For HIV-infected patients with moderate-to-severe PCP, combination therapy with caspofungin and TMP/SMZ is an effective and promising first-line therapy with no greater number of adverse events compared with TMP/SMZ monotherapy. Patients who received caspofungin had better positive response rates and lower all-cause in-hospital mortality rates. Also, we recommend early initiation of caspofungin.

Defining heart disease risk for death in COVID-19 infection

BACKGROUND

Cardiovascular disease (CVD) was in common in coronavirus disease 2019 (COVID-19) patients and associated with unfavorable outcomes. We aimed to compare the clinical observations and outcomes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients with or without CVD.

METHODS

Patients with laboratory-confirmed SARS-CoV-2 infection were clinically evaluated at Wuhan Seventh People's Hospital, Wuhan, China, from 23 January to 14 March 2020. Demographic data, laboratory findings, comorbidities, treatments and outcomes were collected and analyzed in COVID-19 patients with and without CVD.

RESULTS

Among 596 patients with COVID-19, 215 (36.1%) of them with CVD. Compared with patients without CVD, these patients were significantly older (66 vs. 52 years) and had higher proportion of men (52.5% vs. 43.8%). Complications in the course of disease were more common in patients with CVD, included acute respiratory distress syndrome (22.8% vs. 8.1%), malignant arrhythmias (3.7% vs. 1.0%) including ventricular tachycardia/ventricular fibrillation, acute coagulopathy(7.9% vs. 1.8%) and acute kidney injury (11.6% vs. 3.4%). The rate of glucocorticoid therapy (36.7% vs. 25.5%), Vitamin C (23.3% vs. 11.8%), mechanical ventilation (21.9% vs. 7.6%), intensive care unit admission (12.6% vs. 3.7%) and mortality (16.7% vs. 4.7%) were higher in patients with CVD (both P < 0.05). The multivariable Cox regression models showed that older age (≥65 years old) (HR 3.165, 95% CI 1.722-5.817) and patients with CVD (HR 2.166, 95% CI 1.189-3.948) were independent risk factors for death.

CONCLUSIONS

CVD are independent risk factors for COVID-19 patients. COVID-19 patients with CVD were more severe and had higher mortality rate, early intervention and vigilance should be taken.

Allostery of DNA nanostructures controlled by enzymatic modifications

Allostery is comprehensively studied for natural macromolecules, such as proteins and nucleic acids. Here, we present controllable allostery of synthetic DNA nanostructure–enzyme systems. Rational designs of the synthetic allosteric systems are based on an in-depth understanding of allosteric sites with several types of strand placements, whose varying stacking strengths determine the local conformation and ultimately lead to a gradient level of allosteric transition. When enzymes in a molecular cloning toolbox such as DNA polymerase, exonuclease and ligase are applied to treat the allosteric sites, the resulting local conformational changes propagate through the entire structure for a global allosteric transition.

[Surgical selection and metastatic warning of splenic lymph node dissection in advanced gastric cancer radical surgery: a prospective, single-center, randomized controlled trial]

Objective: To investigate the surgical options for splenic lymph node dissection in patients with advanced gastric cancer undergoing radical total gastrectomy, and to evaluate the sentinel effect of No. 4s lymph node on splenic lymph node metastasis. Methods: A prospective, single-center, randomized and controlled study was carried out (Trial registration, No.NCT02980861). Enrollment criteria: (1) >18 years old and <65 years old; (2) gastric adenocarcinoma locating in the proximal or corpus; (3) preoperative clinical staging as cT2-4aN0-3M0; (4) D2 radical total gastrectomy feasible judged before operation; (5) physical ability score 0 to 1; (6) I to III of ASA classification. Pregnant or lactating women, patients with severe mental illness or previous history of upper abdominal surgery, those suffered from other malignant tumors in the past 5 years, or heart and lung system diseases judged to affect surgery before operation, those receiving preoperative chemotherapy, radiotherapy or targeted therapies, and distant metastases being found during surgery were excluded. According to above criteria, 222 patients at The First Medical Center of Chinese PLA General Hospital from December 2016 to December 2017 were enrolled prospectively and were randomly divided into the laparoscopic splenic hilar lymph node dissection group (laparoscopic group, n=114) and the open splenic hilar lymph node dissection group (open group, n=108). The result of rapid frozen immunohistochemistry of harvested No.4s lymph nodes was used to evaluate the sensitivity and specificity of sentinel effect on splenic hilar lymph node metastasis. The surgical parameters, postoperative recovery parameters, and complication rates were compared between the two groups. Results: There were 80 males and 34 females in the lapascopic group with a mean age of (56.1±10.2) years, and 69 males and 39 females in the open group with a mean age of (58.4±10.9) years. There were no significant differences in baseline data between the two groups (all P>0.05). Total blood loss was less in the laparoscopic group [(96.3±82.4) ml vs. (116.6±101.9) ml, t=1.124, P<0.001], and the amount of bleeding from the splenic hilar lymph nodes dissected was also less than that in the open group [(25.3±17.8) ml vs. (59.5±36.4) ml, t=1.172, P<0.001]. However, the operation time, the time of splenic hilar lymph node, the number of lymph node dissected and number of splenic hilar lymph node dissected were not significantly different between the two groups (all P>0.05). As compared to the open group, the laparoscopic group had shorter time to the first flatus [(1.3±1.2) days vs. (1.6±1.5) days, t=1.665, P=0.021], shorter time to fluid diet [(4.6±1.4) days vs. (4.9 ± 1.6) days, t=1.436, P=0.007], shorter time to remove nasogastric tube [(3.9±2.6) days vs. (4.3±2.4) days, t=0.687, P<0.001] and shorter hospital stay [(10.3±6.6) days vs. (12.1±7.2) days, t=0.697, P<0.001]. Complication rate was 14.0% (16/114) and (12.0%) ((1)3/108) in the laparoscopic group and the open group, respectively, without significant difference (χ(2)=6.723, P=0.331). The sensitivity of the No. 4s lymph node for the prediction of splenic hilar lymph node metastasis reached 89.5%, and the specificity reached 99.6%. Conclusions: Laparoscopic technique is safe and feasible in the treatment of splenic hilar lymph node dissection in advanced gastric cancer. The No.4s lymph node examination has good sentinel effect on predicting the metastasis of splenic hilar lymph nodes.

Using chemical fractionation and speciation to describe uptake of technetium, iodine and selenium by Agrostis capillaris and Lolium perenne

To understand the dynamic mechanisms governing soil-to-plant transfer of selenium (Se), technetium-99 (⁹⁹Tc) and iodine (I), a pot experiment was undertaken using 30 contrasting soils after spiking with ⁷⁷Se, ⁹⁹Tc and ¹²⁹I, and incubating for 2.5 years. Two grass species (Agrostis capillaris and Lolium perenne) were grown under controlled conditions for 4 months with 3 cuts at approximately monthly intervals. Native (soil-derived) ⁷⁸Se and¹²⁷I, as well as spiked ⁷⁷Se, ⁹⁹Tc and ¹²⁹I, were assayed in soil and plants by ICP-MS. The grasses exhibited similar behaviour with respect to uptake of all three elements. The greatest uptake observed was for ⁹⁹Tc, followed by ⁷⁷Se, with least uptake of ¹²⁹I, reflecting the transformations and interactions with soil of the three isotopes. Unlike soil-derived Se and I, the available pools of ⁷⁷Se, ⁹⁹Tc and ¹²⁹I were substantially depleted by plant uptake across the three cuts with lower concentrations observed in plant tissues in each subsequent cut. Comparison between total plant offtake and various soil species suggested that ⁷⁷SeO₄^2-, ⁹⁹TcO₄^- and ¹²⁹IO₃^-, in soluble and adsorbed fractions were the most likely plant-available species. A greater ratio of ¹²⁷I/¹²⁹I in the soil solid phase compared to the solution phase confirmed incomplete mixing of spiked ¹²⁹I with native ¹²⁷I in the soil, despite the extended incubation period, leading to poor buffering of the spiked available pools. Compared to traditional expressions of soil-plant transfer factor (TF_total), a transfer factor (TF_available) expressed using volumetric concentrations of speciated 'available' fractions of each element showed little variation with soil properties.

Addressable DNA nanotubes with repetitive components

Extended DNA nanostructures have already been constructed in a repetitive arrangement from millions of building blocks, many more than currently feasible with even the gold standard of addressable self-assembled structures. In order to construct addressable DNA nanostructures with more building blocks, it is desirable to arrange the addressable components repetitively. Accordingly, the overall size of the structure can be multiplied by the level of repetition in the addressable strands. In this study, we present a nanotube system that combines two seemingly conflicting features: addressability and repetitiveness. Based on an understanding of the tubulation resulting from the intrinsic curvature of the components, we produce DNA nanotubes with addressability available along the axial direction of the self-assembled tubes, which are also programmably repetitive along the lateral direction.

LncRNA SNHG7 promotes the proliferation of esophageal cancer cells and inhibits its apoptosis

OBJECTIVE

Our research studied the expression of long noncoding RNA (lncRNA) SNHG7 in esophageal cancer cells and tissues. The effect of lncRNA SNHG7 on proliferation and apoptosis of esophageal cancer cells has been discussed.

PATIENTS AND METHODS

Si-SNHG7 was transfected into esophageal cancer cells, and qRT-PCR was performed to detect the expression of lncRNA SNHG7 in esophageal cancer cells and tissues. The effect of SNHG7 on the proliferation of esophageal cancer cells was measured by CCK8 assay and plate cloning assay, respectively. Flow cytometry was used to detect the effect of SNHG7 on the cell cycle and apoptosis rate of esophageal cancer cells. Changes in expression of downstream protein p15 and p16 after si-SNHG7 intervention were analyzed by qRT-PCR and Western blot.

RESULTS

QRT-PCR showed that the expression of SNHG7 in esophageal cancer tissues and cells was significantly up-regulated. After the si-SNHG7 intervention, the proliferation of esophageal cancer cells was inhibited, the apoptosis rate increased, and the cell cycle was blocked in G1-G0 phase. QRT-PCR and Western blot showed that, after the si-SNHG7 intervention, the expression of p15 and p16 increased significantly.

CONCLUSIONS

The expression of SNHG7 in the tissues and cells of esophageal cancer is significantly up-regulated. SNHG7 can partly promote the development of esophageal cancer by regulating the expression of p15 and p16.

Long non-coding RNA DUXAP8 regulates proliferation and invasion of esophageal squamous cell cancer

OBJECTIVE

The purpose of this research was to detect the expression of long non-coding RNA DUXAP8 in esophageal cancer, and to explore its underlying mechanism in the development of esophageal squamous cell carcinoma (ESCC).

PATIENTS AND METHODS

We collected 78 pairs of esophageal cancer tissues and normal adjacent tissues. The mRNA level of DUXAP8 in these esophageal cancer tissues and corresponding adjacent tissues was detected by quantitative Real-time polymerase chain reaction (qRT-PCR). The relationship between DUXAP8 expression and the prognosis of esophageal cancer was analyzed. Small interfering RNA (siRNA) was applied to reduce the expression of DUXAP8 in ESCC cell lines (TE-1 and KYSE520). Meanwhile, the specific effect of DUXAP8 on the biological functions of ESCC cells was analyzed by CCK-8 assay (cell counting kit-8), colony formation assay and transwell assay, respectively. Furthermore, the regulatory effect of DUXAP8 on Wnt/β-catenin pathway was detected by Western blot.

RESULTS

DUXAP8 was overexpressed in ESCC tissues than that of normal adjacent tissues. DUXAP8 expression was positively correlated to tumor stage and lymph node metastasis, whereas negatively correlated to the survival rate of ESCC patients. Cell proliferation, colony formation and invasion abilities were significantly decreased after knockdown of DUXAP8 in ESCC cells. Western blot results showed that DUXAP8 could regulate the occurrence of ESCC via Wnt/β-catenin pathway.

CONCLUSIONS

DUXAP8 expression was significantly correlated with tumor stage, lymph node metastasis and poor prognosis of ESCC patients. DUXAP8 may promote the occurrence of ESCC via Wnt/β-catenin pathway.

Nitrogen-aeration tuned ultrasonic synthesis of SiO2@PNIPAm nanoparticles and preparation of temperature responsive Pickering emulsion

Ultrasonic synthesis has shown great potential applications in preparing varieties of nanostructured materials. However, fabrication of nanomaterials with tunable structures and desirable properties is still challenging because of the instability and nonuniform distribution of cavitation effect in liquid phase. In this study, a novel aeration tuned ultrasonic synthesis approach is proposed for optimizing the cavitation effect in both time and space scales and fabricating SiO₂@PNIPAm NPs. By alternation of ultrasonication and N₂ aeration, more and more gas bubbles are formed in the reaction liquid, and the collapse of those bubbles is further enhanced by the reactants of solid SiO₂ and intermediate functionalized SiO₂ NPs. As a result, SiO₂@PNIPAm NPs with various grafting ratios are successfully synthesized simply by changing the number of ultrasonic synthesis cycle. The SiO₂@PNIPAm NPs are subsequently used as stabilizer to form Pickering emulsions with different temperature response. This work provides a potential facile sonochemical synthesis method with high efficiency in obtaining inorganic/organic NPs of well determined structures.

DNA nanostructures from double-C-shaped motifs with controllable twist and curvature

We demonstrate twist and curvature engineering in DNA nanostructures from the scaffold-free approach. The DNA 'LEGO' bricks adopted in this study are double-C-shaped motifs, and extended nanostructures are constructed to visualize the structural details of twist or curvature. By systematically deleting and inserting base pairs at certain domains of the component motifs, we are able to study various levels of the twist and curvature of the resulting nanostructures comprehensively.

Self-Assembly of Wireframe DNA Nanostructures from Junction Motifs

Wireframe frameworks have been investigated for the construction of complex nanostructures from a scaffolded DNA origami approach; however, a similar framework is yet to be fully explored in a scaffold-free "LEGO" approach. Herein, we describe a general design scheme to construct wireframe DNA nanostructures entirely from short synthetic strands. A typical edge of the resulting structures in this study is composed of two parallel duplexes with crossovers on both ends, and three, four, or five edges radiate out from a certain vertex. By using such a self-assembly scheme, we produced planar lattices and polyhedral objects.