[Preliminary clinical experience of the novel transcatheter aortic valve system Prizvalve® for the treatment of severe aortic stenosis]

Objective: To evaluate the safety and efficacy of transcatheter aortic valve implantation (TAVI) with the novel Prizvalve^® system in treating severe aortic stenosis. Methods: This is a single-center, prospective, single-arm, observational study. A total of 11 patients with severe aortic stenosis with high risk or inappropriate for conventional surgical aortic valve replacement (SAVR) were included, and TAVI was achieved with the Prizvalve^® system between March 2021 and May 2021 in West China Hospital. Transthoracic echocardiography (TTE) was performed immediately after prosthesis implantation to evaluate mean transaortic gradient and maximal transaortic velocity. The device success rate was calculated, which was defined as (1) the device being delivered via the access, deployed, implanted and withdrawn, (2) mean transaortic gradient<20 mmHg (1 mmHg=0.133 kPa) or a maximal transaortic velocity<3 m/s post TAVI, and without severe aortic regurgitation or paravalvular leak post TAVI. TTE was performed at 30 days after the surgery, and all-cause mortality as well as the major cardiovascular adverse events (including acute myocardial infarction, disabling hemorrhagic or ischemic stroke) up to 30 days post TAVI were analyzed. Results: The age of 11 included patients were (78.1±6.3) years, with 8 males. A total of 10 patients were with NYHA functional class Ⅲ or Ⅳ. Devices were delivered via the access, deployed, implanted and withdrawn successfully in all patients. Post-implant mean transaortic gradient was (7.55±4.08) mmHg and maximal transaortic velocity was (1.78±0.44) m/s, and both decreased significantly as compared to baseline levels (both P<0.05). No severe aortic regurgitation or paravalvular leak was observed post TAVI. Device success was achieved in all the 11 patients. No patient died or experienced major cardiovascular adverse events up to 30 days post TAVI. Mean transaortic gradient was (9.45±5.07) mmHg and maximal transaortic velocity was (2.05±0.42) m/s at 30 days post TAVI, which were similar as the values measured immediately post TAVI (both P>0.05). Conclusions: TAVI with the Prizvalve^® system is a feasible and relatively safe procedure for patients with severe aortic stenosis and at high risk or inappropriate for SAVR. Further clinical studies could be launched to obtain more clinical experience with Prizvalve^® system.

Key factors determining competitions between double-stranded RNAs in Tribolium castaneum

Combinatorial delivery of different double-stranded RNAs (dsRNAs) can result in competitive inhibition in insect pests and remains one of the obstacles in the way of future applications of the RNA interference (RNAi)-based pest control. In this study, we attempted to discover the basic competition characteristics between dsRNAs and provided insight into the solutions of competitive inhibition. RNAi sensitive insect species Tribolium castaneum were treated, and competitions between dsRNA fragments influencing the effectiveness of RNAi response could be measured. A chimeric dsRNA strategy for conjugating different dsRNA fragments into a single molecule and a nanoparticle carbon quantum dots-mediated dsRNA delivery were confirmed as efficient methods to knock down multiple target genes simultaneously. Furthermore, in vitro assays were conducted for determining the accumulation speed of serially diluted and incubated dsRNA in the midgut tissues. Our data showed that the accumulation of dsRNAs of different treated amounts was 0.25 μg ≈ 0.5 μg > 1 μg ≥ 2 μg > 4 μg, indicating that accumulation speed would be affected by treated dsRNA. Overall, our results strongly suggest that endocytic components influencing cellular uptake might be oversaturated when an excess amount of dsRNAs were treated, thereby causing competitive inhibition of target genes.

[Research advances on the biomechanical micro- environment facilitated wound repair through the regulation of cell migration]

Biomechanical microenvironment refers to a variety of mechanical signals in the extracellular mechanical microenvironment, which will change correspondingly with time and space. It plays an important role in histological changes such as cell migration, proliferation, and differentiation, and can further affect wound healing. Wound healing is a complex pathophysiological process, and one of the important factors that affects wound healing is whether the cells can efficiently and quickly migrate to the wound center or not. Previous studies have shown that biomechanical microenvironment can not only induce the directional migration of cells, but also improve the migration rate of cells. In the complex natural environment, cells adopt various migration patterns and are dominated by special patterns such as local myosin contractility and extracellular microenvironment. In addition to overcoming the extracellular barrier, cells also need to interact with neighboring cells and tissue through local physical and mechanical forces and signals to complete migration and thus accelerate wound healing. Therefore, in recent years, scholars at home and abroad have been actively developing biological materials based on improving biomechanical microenvironment in order to further promote cell migration and thus accelerate wound healing. This paper reviews the recent research advances on the role of biomechanical environment in wound healing promotion via the regulating of cell migration and the development of related biomaterials.

[The stability and repeatability of radiomics features based on lung diffusion-weighted imaging]

Objective: To evaluate the feasibility, robustness and reproducibility of radiomics features derived from lung diffusion-weighted imaging (DWI). Methods: Thirty patients with pulmonary nodules/masses who underwent magnetic resonance imaging examination in the Department of Radiology, the First Affiliated Hospital of Guangzhou Medical University, from January 4 2019 to May 5 2019, including 16 males and 14 females, aged from 27 to 69 (57±11) years, were prospectively collected. Planar echo imaging (EPI) -DWI and fast spin-echo (TSE) -DWI scans were performed under free-breathing conditions. Each scan was repeated at an interval of 5 minutes, and the corresponding apparent diffusion coefficient (ADC) maps were reconstructed. Each DWI and ADC sequence (a total of eight groups of images) were manually segmented by two radiologists, and a total of 396 radiomics features in 6 categories were extracted from each group of images. Consistency correlation coefficient (CCC) and dynamic range (DR) were used to evaluate the robustness of features between two scans, and stable features were defined as both CCC values and DR values ≥0.85. Intra-observer and interobserver reproducibility were evaluated by intra-group correlation coefficient (ICC), and ICC values≥0.75 was considered to be good reproducibility. Results: Regardless of EPI or TSE technique, the number of robust features extracted fromDWI (TSE: n=197, EPI: n=169) were higher than that of the corresponding ADC (TSE: n=126, EPI: n=148). The proportion of robust features of TSE-DWI、EPI-DWI、TSE-ADC、EPI-ADC was 49.7% (197/396), 42.7% (169/396), 31.8% (126/396) and 37.4% (148/396), respectively. Of the 396 features, 54 (13.6%) of them demonstrated great robustness (CCC and DR≥0.85) and interobserver and interobserver reproducibility (ICC≥0.75) across all sequences. Conclusions: Radiomics features derived from lung DWI showed robustness and reproducibility. Different sequences and different feature clusters have different proportions of stable features, and some features have good robustness and reproducibility between different scans, different observers, and even different sequences.

Experimental and Theoretical Study of the Ultrafast Dynamics of a Ni2 Dy2 -Compound in DMF After UV/Vis Photoexcitation

We present a combined experimental and theoretical study of the ultrafast transient absorption spectroscopy results of a {Ni₂Dy₂}‐compound in DMF, which can be considered as a prototypic molecule for single molecule magnets. We apply state‐of‐the‐art ab initio quantum chemistry to quantitatively describe the optical properties of an inorganic complex system comprising ten atoms to form the chromophoric unit, which is further stabilized by surrounding ligands. Two different basis sets are used for the calculations to specifically identify two dominant peaks in the ground state. Furthermore, we theoretically propagate the compound's correlated many‐body wavefunction under the influence of a laser pulse as well as relaxation processes and compare against the time‐resolved absorption spectra. The experimental data can be described with a time constant of several hundreds of femtoseconds attributed to vibrational relaxation and trapping into states localized within the band gap. A second time constant is ascribed to the excited state while trap states show lifetimes on a longer timescale. The theoretical propagation is performed with the density‐matrix formalism and the Lindblad superoperator, which couples the system to a thermal bath, allowing us to extract relaxation times from first principles.

Ckip-1 Mediates P. gingivalis-Suppressed Cementoblast Mineralization

Porphyromonas gingivalis is responsible for the destruction of cementum in patients with periodontitis and periapical periodontitis. However, research about the effects of P. gingivalis on cementoblast mineralization and the underlying mechanism is still lacking. Casein kinase 2 interacting protein 1 (Ckip-1) is a scaffold protein that interacts with various proteins and signals to regulate different cell functions, such as cell morphology, apoptosis, and differentiation. In this study, we verified the suppressive effects of P. gingivalis and lipopolysaccharide (Pg-LPS) on OCCM-30 mineralization. We also showed that Ckip-1 gradually decreased during OCCM-30 mineralization but increased with the aggravation of Pg-induced inflammation. However, it remained unchanged when cells were stimulated with Pg-LPS, regardless of the concentration and incubation time. Then, more cellular cementum and enhanced Osterix expression were observed in Ckip-1 knockout mice when compared with the wild-type mice. Meanwhile, Ckip-1 silencing significantly enhanced cementoblast mineralization with or without P. gingivalis-associated inflammation. The trend was opposite when Ckip-1 was overexpressed. Finally, we found that the p38, Akt, and Wnt pathways were activated, while the Erk1/2 pathway was inhibited when Ckip-1 was silenced. The opposite results were also observed in the Ckip-1 overexpression group. Furthermore, we proved that cell mineralization was weakened when p38, Akt inhibitors were applied and strengthened when the Erk1/2 pathway was inhibited. In summary, Ckip-1 is upregulated underP. gingivalis-induced inflammation and negatively regulates cementoblast mineralization partially through mitogen-activated protein kinases and Akt signaling pathways, which may contribute to the restoration of cementum destroyed by P. gingivalis.

[Analysing pathogenic bacterial spectrum and drug resistance of bloodstream infection in patients with allogeneic hematopoietic stem cell transplantation]

Objective: To elucidate the clinical characteristics of bloodstream infection in patients with allogeneic hematopoietic stem cell transplantation (allo-HSCT) in our hospital and improves the survival of transplant patients with bloodstream infection. Methods: Two hundred and ten patients with allo-HSCT from the Department of Hematology were retrospectively analyzed between October 2014 and September 2019. Pathogen distribution, drug resistance, risk factors, and outcomes were investigated in 49 allo-HSCT patients with bloodstream infections. Results: Forty-nine of 210 patients with allo-HSCT had bloodstream infection, and 59 pathogenic microorganisms were identified, mainly Gram-negative bacteria (67.8%) , of which E. coli had the highest incidence (23.7%) , CRO accounted for 42.5%, and Grampositive bacteria accounted for 23.7% (without vancomycin or linezolid-resistant strain) . Additionally, fungi accounted for 8.5%. Univariate analysis suggested that the risk factors of bloodstream infection were gender, pretransplant disease status, and conditioning regimen. In contrast, multivariate analysis showed that bloodstream infection was mainly related to conditioning regimens. Further grouping results showed that 77.6% of patients with neutropenia had bloodstream infections, and 22.4% of patients with non-neutropenia had bloodstream infections; 81.0% of patients with active infections before transplantation had bloodstream infections, while bloodstream infection occurred in 16.9% of patients without active infection. Survival analysis showed that long-term survival of patients with bloodstream infection is shorter than that of patients without bloodstream infection and long-term survival of patients with CRO infection is shorter than that of patients without CRO infection. The survival of patients with neutropenia longer than 14 d is shorter than that of patients with neutropenia shorter than 14 d. Furthermore, there is no correlation between whether there is an active infection before transplantation and whether they are in a neutropenic state at the time of infection and survival. Conclusion: Our results suggest that effective prevention of bloodstream infections from drug-resistant bacteria, particularly CRO, shortening the duration of neutropenia, eradication of potential infections before transplantation, and patient-adaptive conditioning could reduce transplant-related mortality and improve prognosis.

Bystander cardiopulmonary resuscitation and automated external defibrillator use after out-of-hospital cardiac arrest: uncovering differences in care and survival across the urban-rural spectrum

Background

Despite regional variation in survival following out-of-hospital cardiac arrest (OHCA), few studies have investigated urban-rural differences in the provision of care and outcomes after OHCA. To better understand the role of pre-hospital care across the urban-rural spectrum, we compared the effects of bystander cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) use on survival after OHCA between geographical settings.

Methods

This retrospective study (2013–2019) used all adult, non-traumatic, and treated OHCAs registered in the Cardiac Arrest Registry to Enhance Survival. The urban/rural status of arrest locations were classified at the census tract level as urban, suburban, large rural, small town, or rural, using the Rural-Urban Commuting Area classification system (Figure). Bystander interventions were grouped into three categories, including no bystander intervention, bystander CPR alone, and bystander AED use (with CPR). The primary outcome of interest was survival to hospital discharge with good neurological outcome. Multivariable logistic regression models were developed to assess the association between bystander interventions and survival with good neurological outcome by urban/rural status, adjusting for relevant covariates.

Results

A total of 325,281 patients were included. Bystander CPR alone occurred most often in rural areas (50.8%), and least often in urban areas (35.4%). Bystander AED use varied by urban/rural status (1.7%-2.9%), with large rural (2.9%) and rural areas (2.4%) reporting the highest rates. Survival to hospital discharge with good neurological outcome differed for urban (8.1%), suburban (7.7%), large rural (9.1%), small town (7.1%), and rural areas (6.1%). In all areas, patients who received bystander AED use or bystander CPR alone were more likely to achieve survival with good neurological outcome than patients who received no bystander intervention. The effect of bystander AED use on survival was stronger than bystander CPR alone in urban, suburban, and rural areas (no overlap of confidence bands), whereas no significant differences between these two bystander intervention groups were observed in large rural areas or small towns (overlap of confidence bands) (Table).

Conclusions

Bystander CPR and AED use are critical components of the response to OHCA across the urban-rural spectrum. The relative impact of bystander interventions on survival varied based on the geographical location of arrests, despite adjusting for numerous potential confounding variables, such as response time. It is possible that unmeasured factors, such as time from collapse to bystander intervention, patient factors, AED accessibility, and CPR quality are contributing to these observed differences. Future research is needed to better understand the response to OHCA across the urban-rural spectrum, which may inform policies for community-specific emergency protocols and planning.

Funding Acknowledgement

Type of funding sources: None.

Lysophosphatidic acid receptor 6 regulated by miR-27a-3p attenuates tumor proliferation in breast cancer

Purpose

Lysophosphatidic acid (LPA) is a bioactive molecule which participates in many physical and pathological processes. Although LPA receptor 6 (LPAR6), the last identified LPA receptor, has been reported to have diverse effects in multiple cancers, including breast cancer, its effects and functioning mechanisms are not fully known.

Methods

Multiple public databases were used to investigate the mRNA expression of LPAR6, its prognostic value, and potential mechanisms in breast cancer. Western blotting was performed to validate the differential expression of LPAR6 in breast cancer tissues and their adjacent tissues. Furthermore, in vitro experiments were used to explore the effects of LPAR6 on breast cancer. Additionally, TargetScan and miRWalk were used to identify potential upstream regulating miRNAs and validated the relationship between miR-27a-3p and LPAR6 via real-time polymerase chain reaction and an in vitro rescue assay.

Results

LPAR6 was significantly downregulated in breast cancer at transcriptional and translational levels. Decreased LPAR6 expression in breast cancer is significantly correlated with poor overall survival, disease-free survival, and distal metastasis-free survival, particularly for hormone receptor-positive patients, regardless of lymph node metastatic status. In vitro gain and loss-of-function assays indicated that LPAR6 attenuated breast cancer cell proliferation. The analyses of TCGA and METABRIC datasets revealed that LPAR6 may regulate the cell cycle signal pathway. Furthermore, the expression of LPAR6 could be positively regulated by miR-27a-3p. The knockdown of miR-27a-3p increased cell proliferation, and ectopic expression of LPAR6 could partly rescue this phenotype.

Conclusion

LPAR6 acts as a tumor suppressor in breast cancer and is positively regulated by miR-27a-3p.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12094-021-02704-8.

[Epidemiological investigation and analysis of etiological characteristics of infection on 3 067 hospitalized pediatric patients with burns]

Objective: To investigate the epidemiological characteristics and etiological distribution of infection on 3 067 hospitalized pediatric patients with burns, and explore the prevention and treatment strategy of pediatric burns. Methods: A cross-sectional survey was conducted. An analysis was performed on the data of 3 067 hospitalized pediatric patients with burns who met the inclusion criteria and were admitted to the First Affiliated Hospital of Army Medical University (the Third Military Medical University) from January 2012 to December 2020, including gender, age, causative factors, locations and severities of burns, seasons of accidents, and the type, source of tissue or body fluid, and drug resistance of pathogenic bacteria. API bacterial identification batten and automatic microbial identification system were applied for pathogen identification. Drug sensitivities of top 3 consistent ratio pathogen identifed were tested with minimum inhibitory concentration and disk diffusion method. WHONET 5.6 software was applied to analyze the data. Results: There were 3 067 hospitalized pediatric patients with burns, including 1 768 boys and 1 299 girls. The majority of pediatric burn patients were >1 and ≤4 years, accounting for 72.9% (2 236/3 067), and the minority of pediatric burn patients were >8 and ≤12 years, accounting for 4.9% (150/3 067). Moderate burns and severe burns of pediatric burn patients accounted for the majority parts, and the proportions of the two were close. The top cause of pediatric burns was scald, accounting for 81.6% (2504/3 067). Extremities were the most common burn sites in that of entire 3 254. The most pediatric burns occurred in winter, accounting for 29.4% (903/3 067). A total of 1 018 strains of pathogenic bacteria were collected from pediatric burn patients, all of which were non-repeated isolates. The pathogens with top five consistent ratio were Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacter cloacae, and Escherichia coli, among which Staphylococcus aureus ranked the first every year. The pathogens were mainly isolated from the wound exudate, accounting for 81.34% (828/1 018). Staphylococcus aureus from 2012 to 2020 showed no resistance to vancomycin, linezolid or teicoplanin while Staphylococcus aureus isolated in 2019 was 100% resistant to macrolides, penicillin, aminoglycosides, and quinolones. Pseudomonas aeruginosa was not resistant to polymyxin B. Acinetobacter baumannii showed a high rate of drug resistance to most antibiotics. Conclusions: Among the pediatric burn patients admitted to the First Affiliated Hospital of Army Medical University (the Third Military Medical University) from 2012 to 2020, the majority are male children aged >1 and ≤4 years with moderate burns. Scalds are the leading cause; and extremities are the common burn sites; and the most pediatric burns occurre in winter. Staphylococcus aureus from wound exudate is the primary pathogen of burn wound infections in pediatric patients.

High dose insulin promotes the proliferation of vascular smooth muscle cells via AP-1/SM-α pathway

Proliferation of vascular smooth muscle cells (VSMCs) participates in multiple cardiovascular disorders, while the mechanism remains unclear. This study aims to investigate the effects of insulin on VSMC. Insulin was used to stimulate rat VSMCs, and the effects on cell cycle and proliferation were subsequently analyzed using flow cytometry. Furthermore, AP-1 and SM-α overexpression vectors were constructed and transfected into VSMCs. AP-1 and SM-α were inhibited by SR11302 and SM-α siRNA, respectively. The mRNA and protein expression levels were subsequently detected using the reversetranscription quantitative polymerase chain reaction and western blotting, respectively. AP-1 and SM-α gene promoter binding sites were determined using luciferase and chromatin immunoprecipitation assays. As a result, we found that high dose of insulin promoted proliferation of VSMCs and increased the percentage of cells in the S phase by downregulating AP-1. AP-1 was identified to bind to the SM-α gene promoter at locus 2-177 to upregulate SM-α gene expression. Inhibition of AP-1 led to the decrease of SM-α expression. Overexpression of SM-α directly suppressed proliferation of VSMCs, while knocking it down promoted the process. Therefore, this study revealed that insulin downregulated the expression of the SM-α gene by inhibiting AP-1, which in turn facilitated proliferation of VSMCs.

Transcript level is a key factor affecting RNAi efficiency

Efficiency is the basis for the application of RNA interference (RNAi) technology. Actually, RNAi efficiency varies greatly among insect species, tissues and genes. Previous efforts have revealed the mechanisms for variation among insect species and tissues. Here, we investigated the reason for variable efficiency among the target genes in the same insect. First, we tested the genes sampled randomly from Tribolium castaneum, Locusta migratoria and Drosophila S2 cells for both their expression levels and sensitivity to RNAi. The results indicated that the genes with higher expression levels were more sensitive to RNAi. Statistical analysis showed that the correlation coefficients between transcript levels and knockdown efficiencies were 0.8036 (n = 90), 0.7255 (n = 18) and 0.9505 (n = 13), respectively in T. castaneum, L. migratoria and Drosophila S2 cells. Subsequently, ten genes with varied expression level in different tissues (midgut and carcass without midgut) of T. castaneum were tested. The results indicated that the higher knockdown efficiency was always obtained in the tissue where the target gene expressed higher. In addition, three genes were tested in different developmental stages, larvae and pupae of T. castaneum. The results found that when the expression level increased after insect pupation, these genes became more sensitive to RNAi. Thus, all the proofs support unanimously that transcript level is a key factor affecting RNAi sensitivity. This finding allows for a better understanding of the RNAi efficiency variation and lead to effective or efficient use of RNAi technology.

Evaluation of candidate reference genes for gene expression analysis in the brassica leaf beetle, Phaedon brassicae (Coleoptera: Chrysomelidae)

The brassica leaf beetle Phaedon brassicae is a notorious defoliator of cruciferous vegetables. However, few molecular studies of this pest have been conducted due to limited sequence data. Recently, RNA sequencing has offered a powerful platform to generate numerous transcriptomic data, which require RT-qPCR to validate target gene expression. The selection of reliable reference genes to normalize RT-qPCR data is a prerequisite for gene expression analysis. In the present study, the expression stabilities of eight candidate reference genes under biotic conditions (development stages and various tissues) and abiotic perturbations (thermal stress and pesticide exposure) were evaluated using four different statistical algorithms. The optimal suites of reference genes were recommended for the respective experimental conditions. For tissue expression analysis, RPL32 and EF-1α were recommended as the suitable reference genes. RPL19 and TBP were the optimal reference genes across different developmental stages. RPL32 and TBP were identified as the most suitable references for thermal stress. Furthermore, RPL32 and RPL19 were ranked as the best references for insecticide exposure. This work provides a systematic exploration of the optimal reference genes for the respective experimental conditions, and our findings would facilitate molecular studies of P. brassicae.