scGAAC: A graph attention autoencoder for clustering single-cell RNA-sequencing data.

Single-cell RNA-sequencing (scRNA-seq) enables the investigation of intricate mechanisms governing cell heterogeneity and diversity. Clustering analysis remains a pivotal tool in scRNA-seq for discerning cell types. However, persistent challenges arise from noise, high dimensionality, and dropout in single-cell data. Despite the proliferation of scRNA-seq clustering methods, these often focus on extracting representations from individual cell expression data, neglecting potential intercellular relationships. To overcome this limitation, we introduce scGAAC, a novel clustering method based on an attention-based graph convolutional autoencoder. By leveraging structural information between cells through a graph attention autoencoder, scGAAC uncovers latent relationships while extracting representation information from single-cell gene expression patterns. An attention fusion module amalgamates the learned features of the graph attention autoencoder and the autoencoder through attention weights. Ultimately, a self-supervised learning policy guides model optimization. scGAAC, a hypothesis-free framework, performs better on four real scRNA-seq datasets than most state-of-the-art methods. The scGAAC implementation is publicly available on Github at: https://github.com/labiip/scGAAC.

Integrated analysis reveals critical cisplatin-resistance regulators E2F7 contributed to tumor progression and metastasis in lung adenocarcinoma.

BACKGROUND: Drug resistance poses a significant challenge in cancer treatment, particularly as a leading cause of therapy failure. Cisplatin, the primary drug for lung adenocarcinoma (LUAD) chemotherapy, shows effective treatment outcomes. However, the development of resistance against cisplatin is a major obstacle. Therefore, identifying genes resistant to cisplatin and adopting personalized treatment could significantly improve patient outcomes. METHODS: By examining transcriptome data of cisplatin-resistant LUAD cells from the GEO database, 181 genes associated with cisplatin resistance were identified. Using univariate regression analysis, random forest and multivariate regression analyses, two prognostic genes, E2F7 and FAM83A, were identified. This study developed a prognostic model utilizing E2F7 and FAM83A as key indicators. The Cell Counting Kit 8 assay, Transwell assay, and flow cytometry were used to detect the effects of E2F7 on the proliferation, migration, invasiveness and apoptosis of A549/PC9 cells. Western blotting was used to determine the effect of E2F7 on AKT/mTOR signaling pathway. RESULTS: This study has pinpointed two crucial genes associated with cisplatin resistance, E2F7 and FAM83A, and developed a comprehensive model to assist in the diagnosis, prognosis, and evaluation of relapse risk in LUAD. Analysis revealed that patients at higher risk, according to these genetic markers, had elevated levels of immune checkpoints (PD-L1 and PD-L2). The prognostic and diagnosis values of E2F7 and FAM83A were further confirmed in clinical data. Furthermore, inhibiting E2F7 in lung cancer cells markedly reduced their proliferation, migration, invasion, and increased apoptosis. In vivo experiments corroborated these findings, showing reduced tumor growth and lung metastasis upon E2F7 suppression in lung cancer models. CONCLUSION: Our study affirms the prognostic value of a model based on two DEGs, offering a reliable method for predicting the success of tumor immunotherapy in patients with LUAD. The diagnostic and predictive model based on these genes demonstrates excellent performance. In vitro, reducing E2F7 levels shows antitumor effects by blocking LUAD growth and progression. Further investigation into the molecular mechanisms has highlighted E2F7's effect on the AKT/mTOR signaling pathway, underscoring its therapeutic potential. In the era of personalized medicine, this DEG-based model promises to guide clinical practice.

Enrichment and Selection of Particles through Parallel Induced-Charge Electro-osmotic Streaming for Detection of Low-Abundance Nanoparticles and Targeted Microalgae.

Manipulation of micro- and nanoscale objects is an essential procedure in many detection and sensing applications, including disease diagnosis and environmental monitoring. Induced-charge electro-osmotic (ICEO) vortices present excellent advantages in the enrichment and selection of micro/nanoscale particles for downstream detection due to gentle conditions and contactless operation, but the application of this method is currently constrained by the throughput. Double-layer charging at the ends of bipolar electrodes can maintain a continuous flow of electric current in the fluidically isolated channels, which provides a feasible method to manipulate particles using parallel ICEO vortices, promoting throughput of particle manipulation without compromising efficiency and overcoming the complicated ohmic contact of electrodes. Encouraged by these, we put forward a novel method with parallel ICEO vortices to manipulate micro/nanoscale samples for downstream detection. First, we study the extension regulation of the low-frequency electric field and mediating effect of the open BPEs on the extended electric field and characterize electric equilibrium states of microparticles and their voltage dependence. Afterward, we leverage this method to enrich nanoparticles for detection of low-abundance nanoparticles with about 20- and 40-fold fluorescence intensities by integrating with a simple fiber-optic sensor. Furthermore, this technique is engineered for the selection of targeted microalgae to continuously detect their proliferation behaviors by combining with a homemade electrical impedance spectroscopy device. This method can reinforce the throughput of ICEO vortices and enables it to integrate with simple and economical sensors to accomplish disease diagnosis and environmental monitoring.

Evaluation of resazurin microplate method for rapid detection of vancomycin and linezolid resistance in Enterococcus faecalis and Enterococcus faecium clinical isolates.

BACKGROUND: Vancomycin and linezolid resistance among enterococci is an increasing problem due to a lack of alternative antibiotics. Early identification of vancomycin-resistant and linezolid-resistant strains can help prevent the spread of resistance to these antibiotics. Hence, early, rapid and accurate detection of vancomycin and linezolid resistance is critical. OBJECTIVES: The resazurin microplate method (RMM) was developed for detecting vancomycin and linezolid susceptibility among Enterococcus faecalis (E. faecalis) and Enterococcus faecium (E. faecium) clinical isolates, and its performance was further evaluated. METHODS: A total of 209 non-duplicate clinical isolates and three strains from the faeces of domestic animals, including 142 E. faecalis (71 linezolid non-susceptible and 71 linezolid susceptible) and 70 E. faecium (23 vancomycin non-susceptible, 23 vancomycin susceptible, 12 linezolid non-susceptible and 12 linezolid susceptible), were tested using RMM. RESULTS: The susceptibility of E. faecium to vancomycin was detected within 5 h, with high susceptibility (23/23) and specificity (23/23). The susceptibility of E. faecalis and E. faecium to linezolid was detected within 4 h, with specificities of 98.59% and 100% and susceptibilities of 94.37% and 58.33% for E. faecalis and E. faecium, respectively. CONCLUSIONS: RMM had a good positive predictive value for the detection of vancomycin-non-susceptible E. faecium and linezolid-non-susceptible E. faecalis. It thus has the potential to become an alternative method for the rapid screening of these resistant pathogens in clinical practice.

Effect of chlorogenic acid on the quorum-sensing system of clinically isolated multidrug-resistant Pseudomonas aeruginosa.

AIMS: Quorum sensing (QS) is the intercellular communication used by bacteria to regulate collective behaviour. QS regulates the production of virulence factors in many bacterial species and is considered to be an attractive target for reducing bacterial pathogenicity. Chlorogenic acid (CA) is abundant in vegetables, fruits, and traditional Chinese medicine, and has multiple activities. This study aimed to investigate the QS quenching activity of CA against clinically isolated multidrug-resistant Pseudomonas aeruginosa. METHODS AND RESULTS: The results showed that CA inhibited the mobility of bacteria, reduced the production of pyocyanin, and inhibited the activity of elastase. Furthermore, crystal violet staining and scanning electron microscope experiments showed that CA inhibited the formation of multidrug-resistant P. aeruginosa biofilm. CA at or below the concentration of 2560 µg/mL exerted negligible cytotoxicity to RAW264.7 cells. The study also examined the expression of QS-related genes, including lasI, lasR, rhlI, rhlR, pqsA, and pqsR in P. aeruginosa and found that the expression of these genes was down-regulated under CA treatment. CONCLUSIONS: The study showed that CA could be used as an anti-virulence factor for treating clinical P. aeruginosa infection. SIGNIFICANCE AND IMPACT OF STUDY: For the first time, this study took clinically isolated multidrug-resistant P. aeruginosa as the experimental object, and suggested that CA might be an effective antimicrobial compound targeting QS in treating P. aeruginosa infection, thus providing a new therapeutic direction for treating bacterial infection and effectively alleviating bacterial resistance.

The prevalence and functional characteristics of CrpP-like in Pseudomonas aeruginosa isolates from China.

Modifying enzyme-CrpP and its variants reduced the MICs of fluoroquinolones in Pseudomonas aeruginosa. This study investigated the dissemination and functional characteristics of CrpP-like in P. aeruginosa from China. The positive rate of crpP-like genes in 228 P. aeruginosa was 25.4% (58/228), and 6 new crpP-like genes were determined. Transformation experiments showed that CrpP-like had a low effect on CIP and LEV susceptibility. The genetic of crpP-positive was diverse. Furthermore, the mean expression level of crpP was no statistical difference between fluoroquinolone-susceptible and -resistant group (P > 0.05). CrpP-like may not play a significant role in fluoroquinolone resistance in P. aeruginosa.

Improving mass-univariate analysis of neuroimaging data by modelling important unknown covariates: Application to Epigenome-Wide Association Studies.

Statistical inference on neuroimaging data is often conducted using a mass-univariate model, equivalent to fitting a linear model at every voxel with a known set of covariates. Due to the large number of linear models, it is challenging to check if the selection of covariates is appropriate and to modify this selection adequately. The use of standard diagnostics, such as residual plotting, is clearly not practical for neuroimaging data. However, the selection of covariates is crucial for linear regression to ensure valid statistical inference. In particular, the mean model of regression needs to be reasonably well specified. Unfortunately, this issue is often overlooked in the field of neuroimaging. This study aims to adopt the existing Confounder Adjusted Testing and Estimation (CATE) approach and to extend it for use with neuroimaging data. We propose a modification of CATE that can yield valid statistical inferences using Principal Component Analysis (PCA) estimators instead of Maximum Likelihood (ML) estimators. We then propose a non-parametric hypothesis testing procedure that can improve upon parametric testing. Monte Carlo simulations show that the modification of CATE allows for more accurate modelling of neuroimaging data and can in turn yield a better control of False Positive Rate (FPR) and Family-Wise Error Rate (FWER). We demonstrate its application to an Epigenome-Wide Association Study (EWAS) on neonatal brain imaging and umbilical cord DNA methylation data obtained as part of a longitudinal cohort study. Software for this CATE study is freely available at http://www.bioeng.nus.edu.sg/cfa/Imaging_Genetics2.html.

Ultrathin Cell-Membrane-Mimic Phosphorylcholine Polymer Film Coating Enables Large Improvements for In†Vivo Electrochemical Detection.

Resisting biomolecule adsorption onto the surface of brain-implanted microelectrodes is a key issue for in vivo monitoring of neurochemicals. Herein, we demonstrate that an ultrathin cell-membrane-mimic film of ethylenedioxythiophene tailored with zwitterionic phosphorylcholine (EDOT-PC) electropolymerized onto the surface of a carbon fiber microelectrode (CFE) not only resists protein adsorption but also maintains the sensitivity and time response for in vivo monitoring of dopamine (DA). As a consequence, the as-prepared PEDOT-PC/CFEs could be used as a new reliable platform for tracking DA in vivo and would help understand the physiological and pathological functions of DA.

Diversity of sugar acceptor of glycosyltransferase 1 from Bacillus cereus and its application for glucoside synthesis.

Glycosyltransferase 1 from Bacillus cereus (BcGT1) catalyzes the transfer of a glucosyl moiety from uridine diphosphate glucose (UDP-glucose) to various acceptors; it was expressed and characterized. The specificity of acceptors was found to be broad: more than 20 compounds classified into O-, S-, and N-linkage glucosides can be prepared with BcGT1 catalysis. Based on this work, we conclude that the corresponding acceptors of these compounds must possess the following features: (1) the acceptors must contain at least one aromatic or fused-aromatic or heteroaromatic ring; (2) the reactive hydroxyl or sulfhydryl or amino group can attach either on the aromatic ring or on its aliphatic side chain; and (3) the acceptors can be a primary, secondary, or even a tertiary amine. Four representative acceptors-fluorescein methyl ester, 17-ß-estradiol, 7-mercapto-4-methylcoumarin, and 6-benzylaminopurine-were chosen as a candidate acceptor for O-, S-, and N-glucosidation, respectively. These enzymatic products were purified and the structures were confirmed with mass and NMR spectra. As all isolated glucosides are ß-anomers, BcGT1 is confirmed to be an inverting enzyme. This study not only demonstrates the substrate promiscuity of BcGT1 but also showed the great application prospect of this enzyme in bioconversion of valuable bioactive molecules.

Interaction between common variants of FTO and MC4R is associated with risk of PCOS.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a common and complex endocrine-metabolic disease. One of the well-documented characteristics of PCOS is obesity or overweightness. It is possible to be genetically predisposed to becoming obese or overweight, and several potentially causative single nucleotide polymorphisms (SNPs), such as rs9939609 (A/T) in the fat mass, and obesity-associated gene (FTO) and rs17782313 (T/C) in the melanocortin-4 receptor gene (MC4R), have been investigated. Further investigation of association between obesity-associated SNPs and PCOS susceptibility will contribute to a better understanding of the disease. METHODS: In the present study, we enrolled 733 patients with PCOS and 892 control subjects. The common variants FTO rs9939609 and MC4R rs17782313 were genotyped and their relationship with obesity-related traits was evaluated. RESULTS: Rs9939609 and rs17782313 are associated with PCOS and obesity-related traits and profiles. The association found between PCOS and FTO rs9939609 (p=0.0302) was attenuated after adjustment for BMI (p=0.187). MC4R rs17782313 did not confer an increased risk for PCOS (p=0.368) even after adjustments (p=0.715). Interestingly, the interaction of FTO and MC4R polymorphisms was more significantly associated with PCOS (p=0.031, adjusted for age and BMI). The FTO variant rs9939609 is associated with Chinese women with PCOS; however, this association is affected by BMI. CONCLUSIONS: The combined pathogenic effect of FTO and MC4R polymorphisms indicates a direct role of the interaction between FTO and MC4R polymorphisms in the development of PCOS.

Speciation Analysis of Labile and Total Silver(I) in Nanosilver Dispersions and Environmental Waters by Hollow Fiber Supported Liquid Membrane Extraction.

Hollow fiber supported liquid membrane (HFSLM) extraction was coupled with ICP-MS for speciation analysis of labile Ag(I) and total Ag(I) in dispersions of silver nanoparticles (AgNPs) and environmental waters. Ag(I) in aqueous samples was extracted into the HFSLM of 5%(m/v) tri-n-octylphosphine oxide in n-undecane, and stripped in the acceptor of 10 mM Na2S2O3 and 1 mM Cu(NO3)2 prepared in 5 mM NaH2PO4-Na2HPO4 buffer (pH 7.5). Negligible depletion and exhaustive extraction were conducted under static and 250 rpm shaking to extract the labile Ag(I) and total Ag(I), respectively. The extraction equilibration was reached in 8 h for both extraction modes. The extraction efficiency and detection limit were (2.97 ± 0.25)% and 0.1 µg/L for labile Ag(I), and (82.3 ± 2.0)% and 0.5 µg/L for total Ag(I) detection, respectively. The proposed method was applied to determine labile Ag(I) and total Ag(I) in different sized AgNP dispersions and real environmental waters, with spiked recoveries of total Ag(I) in the range of 74.0-98.1%. With the capability of distinguishing labile and total Ag(I), our method offers a new approach for evaluating the bioavailability and understanding the fate and toxicity of AgNPs in aquatic systems.

[Association of polymorphism in the promoter region of PCA3 gene with risk of prosate cancer].

OBJECTIVE: To investigate the polymorphism in the promoter region of PCA3 gene and its relationship with risk of prostate cancer (PCa). METHODS: The promoter region of PCA3 gene of the DNA of peripheral blood mononuclear cells was detected by sequence analysis in the 186 PCa and 141 BPH patients and 135 healthy control individuals. If the samples were detected with polymorphism of insection/deletion, clone sequence analysis was used with pBS-T carrier to verify it. RESULTS: There were 5 polymorphisms. TAAA repeat times: 4, 5, 6, 7, 8, and 8 genotypes (TAAA 4/5, TAAA 4/6, TAAA 5/5, TAAA 5/6, TAAA 5/7, TAAA 5/8, TAAA 6/6, and TAAA 6/7) were detected in the promoter region of PCA3 gene. The eight genotypes were divided into three groups: ≤10TAAA, 11TAAA, ≥12TAAA. Unconditional logistic regression analysis models were used to analyze the relationship between different genotypes and cancer risks adjusted by sex and age. The type 11TAAA and ≥12TAAA was associated with higher relative risk for prostate cancer than the group ≤10TAAA [OR=1.74, 95% CI=1.06-2.87 (for type 11TAAA); OR=5.63, 95% CI=1.85-17.19 (for type ≥12TAAA)]. In the 186 PCa patients, there was 62.4% allele of PCA3 gene with AG/CA mutation found in the promoter 18-19 bp region of PCA3 gene and it had a close relation with the development of prostate cancer. CONCLUSIONS: Short tandem repeats are found in the promoter region of the PCA3 gene in PCa patients, and the increase of TAAA repeat sequences highly enhance the relative risk of prostate cancer development. The occurrence of such STR might be related to the mutations in their upstream loci.

N1-guanyl-1,7-diaminoheptane sensitizes bladder cancer cells to doxorubicin by preventing epithelial-mesenchymal transition through inhibition of eukaryotic translation initiation factor 5A2 activation.

Drug resistance greatly reduces the efficacy of doxorubicin-based chemotherapy in bladder cancer treatment; however, the underlying mechanisms are poorly understood. We aimed to investigate whether N1-guanyl-1,7-diaminoheptane (GC7), which inhibits eukaryotic translation initiation factor 5A2 (eIF5A2) activation, exerts synergistic cytotoxicity with doxorubicin in bladder cancer, and whether eIF5A2 is involved in chemoresistance to doxorubicin-based bladder cancer treatment. BIU-87, J82, and UM-UC-3 bladder cancer cells were transfected with eIF5A2 siRNA or negative control siRNA before incubation with doxorubicin alone or doxorubicin plus GC7 for 48 h. Doxorubicin cytotoxicity was enhanced by GC7 in BIU-87, J82, and UM-UC-3 cells. It significantly inhibited activity of eIF5A2, suppressed doxorubicin-induced epithelial-mesenchymal transition in BIU-87 cells, and promoted mesenchymal-epithelial transition in J82 and UM-UC-3 cells. Knockdown of eIF5A2 sensitized bladder cancer cells to doxorubicin, prevented doxorubicin-induced EMT in BIU-87 cells, and encouraged mesenchymal-epithelial transition in J82 and UM-UC-3 cells. Combination therapy with GC7 may enhance the therapeutic efficacy of doxorubicin in bladder cancer by inhibiting eIF5A2 activation and preventing epithelial-mesenchymal transition.

Long noncoding RNA PCA3 gene promoter region is related to the risk of prostate cancer on Chinese males.

INTRODUCTION: Long noncoding RNA prostate cancer gene antigen 3 (PCA3) is one of the most prostate cancer-specific genes at present. Consequently, the prostate-specific expression and the sharp up-regulation of PCA3 RNA in prostate cancer suggest a unique transcriptional regulation, which possibly can be attributed to promoter polymorphism. In this study, we investigated a short tandem repeat (STR) polymorphism of TAAA in the promoter region of PCA3 gene found in our previous study in prostate cancer (PCa) patients and benign prostatic hypertrophy (BPH) patients, aiming to evaluate the association between the STR and increased risk for PCa. MATERIAL AND METHODS: 120 PCa cases and 120 benign prostatic hypertrophy (BPH) cases were identified among participants. The region encompassing the TAAA repeat was amplified with a specific primer set we designed and screened by PCR-based cloning and sequencing in paired peripheral blood leukocytes and prostate tissues. Genotype-specific risks were estimated as odds ratios (ORs) associated with 95% confidence intervals (CIs) and adjusted for age by means of unconditional logistic regression. RESULTS: 5 PCA3 TAAA STR polymorphisms and 8 genotypes were found in both peripheral blood leukocytes and prostate tissues, the carriers with more TAAA repeats were associated with increased risk for PCa than individuals having less TAAA repeats. Interestingly, 18 (15.0%) of 120 PCa patients had more (TAAA)n repeats in prostate tissues than that in peripheral blood leukocytes, and 3 (2.5%) of 120 had less (TAAA)n repeats in prostate tissues. CONCLUSIONS: The results of this study suggest that short tandem repeat polymorphism of TAAA in the promoter region of PCA3 gene is a risk-increasing factor for prostate cancer in the Chinese population. In addition to the hereditary factor, the insertion mutation of (TAAA)n in a local tissue maybe another mechanism of the onset of PCa.

Highly dynamic PVP-coated silver nanoparticles in aquatic environments: chemical and morphology change induced by oxidation of Ag(0) and reduction of Ag(+).

The fast growing and abundant use of silver nanoparticles (AgNPs) in commercial products alerts us to be cautious of their unknown health and environmental risks. Because of the inherent redox instability of silver, AgNPs are highly dynamic in the aquatic system, and the cycle of chemical oxidation of AgNPs to release Ag(+) and reconstitution to form AgNPs is expected to occur in aquatic environments. This study investigated how inevitable environmentally relevant factors like sunlight, dissolved organic matter (DOM), pH, Ca(2+)/Mg(2+), Cl(-), and S(2-) individually or in combination affect the chemical transformation of AgNPs. It was demonstrated that simulated sunlight induced the aggregation of AgNPs, causing particle fusion or self-assembly to form larger structures and aggregates. Meanwhile, AgNPs were significantly stabilized by DOM, indicating that AgNPs may exist as single particles and be suspended in natural water for a long time or delivered far distances. Dissolution (ion release) kinetics of AgNPs in sunlit DOM-rich water showed that dissolved Ag concentration increased gradually first and then suddenly decreased with external light irradiation, along with the regeneration of new tiny AgNPs. pH variation and addition of Ca(2+) and Mg(2+) within environmental levels did not affect the tendency, showing that this phenomenon was general in real aquatic systems. Given that a great number of studies have proven the toxicity of dissolved Ag (commonly regarded as the source of AgNP toxicity) to many aquatic organisms, our finding that the effect of DOM and sunlight on AgNP dissolution can regulate AgNP toxicity under these conditions is important. The fact that the release of Ag(+) and regeneration of AgNPs could both happen in sunlit DOM-rich water implies that previous results of toxicity studies gained by focusing on the original nature of AgNPs should be reconsidered and highlights the necessity to monitor the fate and toxicity of AgNPs under more environmentally relevant conditions.

Dielectrophoretic characterization and selection of non-spherical flagellate algae in parallel channels with right-angle bipolar electrodes.

Non-spherical flagellate algae play an increasingly significant role in handling problematic issues as versatile biological micro/nanorobots and resources of valuable bioproducts. However, the commensalism of flagellate algae with distinct structures and constituents causes considerable difficulties in their further biological utilization. Therefore, it is imperative to develop a novel method to realize high-efficiency selection of non-spherical flagellate algae in a non-invasive manner. Enthused by these, we proposed a novel method to accomplish the selection of flagellate algae based on the numerical and experimental investigation of dielectrophoretic characterizations of flagellate algae. Firstly, an arbitrary Lagrangian-Eulerian method was utilized to study the electro-orientation and dielectrophoretic assembly process of spindle-shaped and ellipsoid-shaped cells in a uniform electric field. Secondly, we studied the equilibrium state of spherical, ellipsoid-shaped, and spindle-shaped cells under positive DEP forces actuated by right-angle bipolar electrodes. Thirdly, we investigated the dielectrophoretic assembly and escape processes of the non-spherical flagellate algae in continuous flow to explore their influences on the selection. Fourthly, freshwater flagellate algae (Euglena, H. pluvialis, and C. reinhardtii) and marine ones (Euglena, Dunaliella salina, and Platymonas) were separated to validate the feasibility and adaptability of this method. Finally, this approach was engineered in the selection of Euglena cells with high viability and motility. This method presents immense prospects in the selection of pure non-spherical flagellate algae with high motility for chronic wound healing, bio-micromotor construction, and decontamination with advantages of no sheath, strong reliability, and shape-insensitivity.

Local risk factors for one-year dental implant loss and late loss in 287 failed implants caused by peri-implantitis or infection after prosthesis loading: a retrospective study.

The purpose of this paper was to retrospectively assess the local factors that are likely to be associated with the risks for one-year dental implant loss.A retrospective study was designed and implemented. The sample consisted of patients who underwent an implant loss or removal caused by peri-implantitis or infection after prosthesis loading. The chi-squared test and generalised estimating equations (GEE) were used to explore the potential risk factors for one-year implant loss. A total of 279 patients with 287 failed implants were enrolled in this study. Immediate implant placement exhibited a 3.373 (95% CI: 1.652 to 6.886) significantly increased risk to experience one-year implant loss than early and late implant placement (p = 0.001). In addition, implants loaded during a healing period fewer than two months after implant placement were at 18.139 (95% CI: 8.925 to 36.866) significantly higher risk of one-year implant loss when compared with those that loaded within more than two months after implant placement (p < 0.001). Smokers were 1.866 (OR = 1.866,95% CI: 0.993 to 3.510) times as high risk for one-year implant loss as non-smokers, but there were no significant statistical differences (p = 0.053). Immediate implant placement and early implant loading were considered risk factors for one-year implant loss.

Azomycin Orchestrate Colistin-Resistant Enterobacter cloacae Complex's Colistin Resistance Reversal In Vitro and In Vivo.

The Enterobacter cloacae complex (ECC) is a group of nosocomial pathogens that pose a challenge in clinical treatment due to its intrinsic resistance and the ability to rapidly acquire resistance. Colistin was reconsidered as a last-resort antibiotic for combating multidrug-resistant ECC. However, the persistent emergence of colistin-resistant (COL-R) pathogens impedes its clinical efficacy, and novel treatment options are urgently needed. We propose that azomycin, in combination with colistin, restores the susceptibility of COL-R ECC to colistin in vivo and in vitro. Results from the checkerboard susceptibility, time-killing, and live/dead bacterial cell viability tests showed strong synergistic antibacterial activity in vitro. Animal infection models suggested that azomycin-colistin enhanced the survival rate of infected Galleria mellonella and reduced the bacterial load in the thighs of infected mice, highlighting its superior in vivo synergistic antibacterial activity. Crystal violet staining and scanning electron microscopy unveiled the in vitro synergistic antibiofilm effects of azomycin-colistin. The safety of azomycin and azomycin-colistin at experimental concentrations was confirmed through cytotoxicity tests and an erythrocyte hemolysis test. Azomycin-colistin stimulated the production of reactive oxygen species in COL-R ECC and inhibited the PhoPQ two-component system to combat bacterial growth. Thus, azomycin is feasible as a colistin adjuvant against COL-R ECC infection.

PAM-1: an antimicrobial peptide with promise against ceftazidime-avibactam resistant Escherichia coli infection.

Introduction: Antibiotic misuse and overuse have led to the emergence of carbapenem-resistant bacteria. The global spread of resistance to the novel antibiotic combination ceftazidime-avibactam (CZA) is becoming a severe problem. Antimicrobial peptide PAM-1 offers a novel approach for treating infections caused by antibiotic-resistant bacteria. This study explores its antibacterial and anti-biofilm activities and mechanisms against CZA-resistant Escherichia. Coli (E. coli), evaluating its stability and biosafety as well. Methods: The broth microdilution method, growth curve analysis, crystal violet staining, scanning electron microscopy, and propidium iodide staining/N-phenyl-1-naphthylamine uptake experiments were performed to explore the antibacterial action and potential mechanism of PAM-1 against CZA-resistant E. coli. The biosafety in diverse environments of PAM-1 was evaluated by red blood cell hemolysis, and cytotoxicity tests. Its stability was further assessed under different temperatures, serum concentrations, and ionic conditions using the broth microdilution method to determine its minimum inhibitory concentration (MIC). Galleria mellonella infection model and RT-qPCR were used to investigate the in vivo antibacterial and anti-inflammatory effects. Results and discussion: In vitro antibacterial experiments demonstrated that the MICs of PAM-1 ranged from 2 to 8 µg/mL, with its effectiveness sustained for a duration of 24 h. PAM-1 exhibited significant antibiofilm activities against CZA-resistant E. coli (p < 0.05). Furthermore, Membrane permeability test revealed that PAM-1 may exert its antibacterial effect by disrupting membrane integrity by forming transmembrane pores (p < 0.05). Red blood cell hemolysis and cytotoxicity tests revealed that PAM-1 exerts no adverse effects at experimental concentrations (p < 0.05). Moreover, stability tests revealed its effectiveness in serum and at room temperature. The Galleria mellonella infection model revealed that PAM-1 can significantly improve the survival rate of Galleria mellonella (>50%)for in vivo treatment. Lastly, RT-qPCR revealed that PAM-1 downregulates the expression of inflammatory cytokines (p < 0.05). Overall, our study findings highlight the potential of PAM-1 as a therapeutic agent for CZA-resistant E. coli infections, offering new avenues for research and alternative antimicrobial therapy strategies.

Microfluidic impedance cytometry with flat-end cylindrical electrodes for accurate and fast analysis of marine microalgae.

Marine microalgae play an increasingly significant role in addressing the issues of environmental monitoring and disease treatment, making the analysis of marine microalgae at the single-cell level an essential technique. For this, we put forward accurate and fast microfluidic impedance cytometry to analyze microalgal cells by assembling two cylindrical electrodes and microchannels to form a three-dimensional detection zone. Firstly, we established a mathematical model of microalgal cell detection based on Maxwell's mixture theory and numerically investigated the effects of the electrode gap, microalgal positions, and ion concentrations of the solution on detection to optimize detection conditions. Secondly, 80 µm stainless steel wires were used to construct flat-ended cylindrical electrodes and were then inserted into two collinear channels fabricated using standard photolithography techniques to form a spatially uniform electric field to promote the detection throughput and sensitivity. Thirdly, based on the validation of this method, we measured the impedance of living Euglena and Haematococcus pluvialis to study parametric influences, including ion concentration, cell density and electrode gap. The throughput of this method was also investigated, which reached 1800 cells per s in the detection of Haematococcus pluvialis. Fourthly, we analyzed live and dead Euglena to prove the ability of this method to detect the physiological status of cells and obtained impedances of 124.3 Ω and 31.0 Ω with proportions of 15.9% and 84.1%, respectively. Finally, this method was engineered for the analysis of marine microalgae, measuring living Euglena with an impedance of 159.61 Ω accounting for 3.9%, dead Euglena with an impedance of 36.43 Ω accounting for 10.1% and Oocystis sp. with an impedance of 55.00 Ω accounting for about 81.0%. This method could provide a reliable tool to analyze marine microalgae for monitoring the marine environment and treatment of diseases owing to its outstanding advantages of low cost, high throughput and high corrosion resistance.