Continuous flow delivery system for the perfusion of scaffold-based 3D cultures.

The paper-based culture platform developed by Whitesides readily incorporates tissue-like structures into laboratories with established workflows that rely on monolayer cultures. Cell-laden hydrogels are deposited in these porous scaffolds with micropipettes; these scaffolds support the thin gel slabs, allowing them to be evaluated individually or stacked into thick constructs. The paper-based culture platform has inspired many basic and translational studies, each exploring how readily accessible materials can generate complex structures that mimic aspects of tissues in vivo. Many of these examples have relied on static culture conditions, which result in diffusion-limited environments and cells experiencing pericellular hypoxia. Perfusion-based systems can alleviate pericellular hypoxia and other cell stresses by continually exposing the cells to fresh medium. These perfusion systems are common in microfluidic and organ-on-chip devices supporting cells as monolayer cultures or as 3D constructs. Here, we introduce a continuous flow delivery system, which uses parts readily produced with 3D printing to provide a self-contained culture platform in which cells in paper or other scaffolds are exposed to fresh (flowing) medium. We demonstrate the utility of this device with examples of cells maintained in single cell-laden scaffolds, stacks of cell-laden scaffolds, and scaffolds that contain monolayers of endothelial cells. These demonstrations highlight some possible experimental questions that can be enabled with readily accessible culture materials and a perfusion-based device that can be readily fabricated.

Characterization and transmission of plasmid-mediated multidrug resistance in foodborne Vibrio parahaemolyticus.

Objectives: The purpose of this study was to determine the structural features and transferability of the multidrug-resistance (MDR) plasmid, and resistance phenotypes for the tested antimicrobials in foodborne Vibrio parahaemolyticus. Methods: Plasmids were isolated from a V. parahaemolyticus strain of seafood origin, then sequenced using the Illumina NovaSeq 6000 and PacBio Sequel II sequencing platforms to obtain the complete genome data. Characterization of the MDR plasmid pVP52-1, including determination of antimicrobial resistance genes (ARGs), plasmid incompatibility groups, and transferability, was carried out. Results: V. parahaemolyticus strain NJIFDCVp52 contained two circular chromosomes and two circular plasmids (pVP52-1 and pVP52-2). Plasmid typing indicated that pVP52-1 belonged to the incompatibility group IncA/C2 and the sequence type pST3. pVP52-1 carried 12 different ARGs, an IS110-composite transposon consisting of aac(6')-Ib-cr, qnrVC1, aac(6')-Ib, dfrA14, and the IS26-mphA-IS6100 unit flanked by inverted sequences of IS5075 and IS4321. pVP52-2 carried no ARGs. A plasmid elimination assay showed that only pVP52-1 and its ARGs were lost, the loss of resistance to several antimicrobials, causing a change from the ampicillin-ampicillin/sulbactam-cefazolin-cefoxitin-ceftazidime-cefotaxime-imipenem-trimethoprim/sulfamethoxazole resistance pattern to the ampicillin resistance pattern. In accordance, a conjugation transfer assay showed that only pVP52-1 and its ARGs were horizontally transferred, leading to increased antimicrobial resistance in Escherichia coli strain EC600, causing a change from the ampicillin-nalidixic acid resistance pattern to the ampicillin-ampicillin/sulbactam-cefazolin-cefoxitin-ceftazidime-cefotaxime-imipenem-nalidixic acid-chloramphenicol-tetracycline-trimethoprim/sulfamethoxazole-azithromycin resistance pattern. Further transferability experiments revealed that pVP52-1 could be transferred to other enterobacterial strains of E. coli and Salmonella. Discussion: This study emphasizes the urgent need for continued surveillance of resistance plasmids and changes in antimicrobial resistance profiles among the V. parahaemolyticus population.

Supported gel slab scaffolds as a three-dimensional cell-based assay platform.

Cell-based assays are heavily relied on in the drug discovery pipeline, quickly pairing down large compound libraries to a manageable number of drug candidates for further characterization and evaluation. Monolayer cultures in which cells are deposited onto the bottom of well plates are the workhorse of many of these screens despite continued evidence of their inability to predict in vivo responses. Three-dimensional (3D) culture platforms can generate tissue-like environments with more representative cellular phenotypes than monolayers but have proven challenging to incorporate into already-developed workflows. Scaffold-based approaches are a tractable means of generating tissue-like environments, supporting cell-laden gels whose preparation is analogous to depositing cells in a well plate. Here, we describe supported gel slab (SGS) scaffolds prepared from commercially available materials, an adhesive spray, and a laser cutter. These cell-containing scaffolds can readily fit into well plates, providing a format compatible with current liquid handlers and analytical instrumentation. The scaffolds enable the evaluation of cellular responses in individual or stacked structures, which contain extracellular matrix-rich microenvironments. With a series of demonstrations, we highlight the utility of the readily assembled SGS scaffolds to quantify cellular responses. These readouts include confocal microscopy, quantifying cellular invasion in Transwell-like and stacked formats, generating multilayered spheroid-on-demand structures capable of providing spatially resolved maps of drug responses, and identifying potential chemotherapies in a screening application.

Multi-omics and single cell characterization of cancer immunosenescence landscape.

Cellular senescence (CS) is closely related to tumor progression. However, the studies about CS genes across human cancers have not explored the relationship between cancer senescence signature and telomere length. Additionally, single-cell analyses have not revealed the evolutionary trends of malignant cells and immune cells at the CS level. We defined a CS-associated signature, called "senescence signature", and found that patients with higher senescence signature had worse prognosis. Higher senescence signature was related to older age, higher genomic instability, longer telomeres, increased lymphocytic infiltration, higher pro-tumor immune infiltrates (Treg cells and MDSCs), and could predict responses to immune checkpoint inhibitor therapy. Single-cell analysis further reveals malignant cells and immune cells share a consistent evolutionary trend at the CS level. MAPK signaling pathway and apoptotic processes may play a key role in CS, and senescence signature may effectively predict sensitivity of MEK1/2 inhibitors, ERK1/2 inhibitors and BCL-2 family inhibitors. We also developed a new CS prediction model of cancer survival and established a portal website to apply this model ( https://bio-pub.shinyapps.io/cs_nomo/ ).

A Systematic Hierarchical Virtual Screening Model for RhlR Inhibitors Based on PCA, Pharmacophore, Docking, and Molecular Dynamics.

RhlR plays a key role in the quorum sensing of Pseudomonas aeruginosa. The current structure-activity relationship (SAR) studies of RhlR inhibitors mainly focus on elucidating the functional groups. Based on a systematic review of previous research on RhlR inhibitors, this study aims to establish a systematic, hierarchical screening model for RhlR inhibitors. We initially established a database and utilized principal component analysis (PCA) to categorize the inhibitors into two classes. Based on the training set, pharmacophore models were established to elucidate the structural characteristics of ligands. Subsequently, molecular docking, molecular dynamics simulations, and the calculation of binding free energy and strain energy were performed to validate the crucial interactions between ligands and receptors. Then, the screening criteria for RhlR inhibitors were established hierarchically based on ligand structure characteristics, ligand-receptor interaction, and receptor affinity. Test sets were finally employed to validate the hierarchical virtual screening model by comparing it with the current SAR studies of RhlR inhibitors. The hierarchical screening model was confirmed to possess higher accuracy and a true positive rate, which holds promise for subsequent screening and the discovery of active RhlR inhibitors.

Two C-terminal isoforms of Aplysia tachykinin-related peptide receptors exhibit phosphorylation-dependent and phosphorylation-independent desensitization mechanisms.

Diversity, a hallmark of G protein-coupled receptor (GPCR) signaling, partly stems from alternative splicing of a single gene generating more than one isoform for a receptor. Additionally, receptor responses to ligands can be attenuated by desensitization upon prolonged or repeated ligand exposure. Both phenomena have been demonstrated and exemplified by the deuterostome tachykinin signaling system, although the role of phosphorylation in desensitization remains a subject of debate. Here, we describe the signaling system for tachykinin-related peptides (TKRPs) in a protostome, mollusk Aplysia. We cloned the Aplysia TKRP precursor, which encodes three TKRPs (apTKRP-1, apTKRP-2a, and apTKRP-2b) containing the FXGXR-amide motif. In situ hybridization and immunohistochemistry showed predominant expression of TKRP mRNA and peptide in the cerebral ganglia. TKRPs and their posttranslational modifications were observed in extracts of central nervous system ganglia using mass spectrometry. We identified two Aplysia TKRP receptors (apTKRPRs), named apTKRPR-A and apTKRPR-B. These receptors are two isoforms generated through alternative splicing of the same gene and differ only in their intracellular C termini. Structure-activity relationship analysis of apTKRP-2b revealed that both C-terminal amidation and conserved residues of the ligand are critical for receptor activation. C-terminal truncates and mutants of apTKRPRs suggested that there is a C-terminal phosphorylation-independent desensitization for both receptors. Moreover, apTKRPR-B also exhibits phosphorylation-dependent desensitization through the phosphorylation of C-terminal Ser/Thr residues. This comprehensive characterization of the Aplysia TKRP signaling system underscores the evolutionary conservation of the TKRP and TK signaling systems, while highlighting the intricacies of receptor regulation through alternative splicing and differential desensitization mechanisms.

Doughnut-shaped bimetallic Cu-Zn-MOF with peroxidase-like activity for colorimetric detection of glucose and antibacterial applications.

Metal-organic frameworks (MOFs), especially bimetallic MOFs, have attracted widespread attention for simulating the structure and function of natural enzymes. In this study, different morphologies of bimetallic Cu-Zn-MOF with different peroxidase (POD)-like activities were prepared by simply controlling the molar ratio of Cu2+ and Zn2+. Among them, the doughnut-shaped Cu9-Zn1-MOF exhibited the largest POD-like activity. Cu9-Zn1-MOF was combined with glucose oxidase to construct a sensitive and selective glucose colorimetric biosensor with a linear detection range of 10-300 µM and a detection limit of 7.1 µm. Furthermore, Cu9-Zn1-MOF can efficiently convert hydrogen peroxide (H2O2) into hydroxyl radicals that effectively kill both gram-negative and gram-positive bacteria at low H2O2 level. The results of this study may promote the synthesis of bimetallic MOFs and broaden their applications in the biomedical field.

Environmentally Relevant Concentrations of Tetracycline Promote Horizontal Transfer of Antimicrobial Resistance Genes via Plasmid-Mediated Conjugation.

The ubiquitous presence of antimicrobial-resistant organisms and antimicrobial resistance genes (ARGs) constitutes a major threat to global public safety. Tetracycline (TET) is a common antimicrobial agent that inhibits bacterial growth and is frequently detected in aquatic environments. Although TET may display coselection for resistance, limited knowledge is available on whether and how it might influence plasmid-mediated conjugation. Subinhibitory concentrations (3.9-250 ng/mL) of TET promoted horizontal gene transfer (HGT) via the mobilizable plasmid pVP52-1 from the donor Vibrio parahaemolyticus NJIFDCVp52 to the recipient Escherichia coli EC600 by 1.47- to 3.19-fold. The transcription levels of tetracycline resistance genes [tetA, tetR(A)], conjugation-related genes (traA, traD), outer membrane protein genes (ompA, ompK, ompV), reactive oxygen species (ROS)-related genes (oxyR, rpoS), autoinducer-2 (AI-2) synthesis gene (luxS), and SOS-related genes (lexA, recA) in the donor and recipient were significantly increased. Furthermore, the overproduced intracellular ROS generation and increased cell membrane permeability under TET exposure stimulated the conjugative transfer of ARGs. Overall, this study provides important insights into the contributions of TET to the spread of antimicrobial resistance.

The associations of maternal liver biomarkers in early pregnancy with the risk of gestational diabetes mellitus: a prospective cohort study and Mendelian randomization analysis.

Background: Associations of liver function with the risk of gestational diabetes mellitus (GDM) remain unclear. This study aimed to examine the relationship and the potential causality between maternal liver biomarkers and the risk of subsequent GDM, as well as to evaluate the interaction between liver biomarkers and lipids on GDM risk. Methods: In an ongoing Zhoushan Pregnant Women Cohort, pregnant women who finished the first prenatal follow-up record, underwent liver function tests in early pregnancy, and completed the GDM screening were included in this study. Logistic regression models were used to investigate the association, and the inverse-variance weighted method supplemented with other methods of two-sample Mendelian randomization (MR) analysis was applied to deduce the causality. Results: Among 9,148 pregnant women, 1,668 (18.2%) developed GDM. In general, the highest quartile of liver function index (LFI), including ALT, AST, GGT, ALP, and hepatic steatosis index, was significantly associated with an increased risk of GDM (OR ranging from 1.29 to 3.15), especially an elevated risk of abnormal postprandial blood glucose level. Moreover, the causal link between ALT and GDM was confirmed by the MR analysis (OR=1.28, 95%CI:1.05-1.54). A significant interaction between AST/ALT and TG on GDM risk was observed (P interaction = 0.026). Conclusion: Elevated levels of LFI in early pregnancy were remarkably associated with an increased risk of GDM in our prospective cohort. Besides, a positive causal link between ALT and GDM was suggested.

Reactive Oxygen Species Modulate Th17/Treg Balance in Chlamydia psittaci Pneumonia via NLRP3/IL-1ß/Caspase-1 Pathway Differentiation.

Chlamydia psittaci pneumonia (CPP) is a lung disease caused by the infection with the Chla-mydia psittaci bacterium, which can lead to severe acute respiratory distress syndrome and systemic symptoms. This study explored the specific mechanisms underlying the impact of reactive oxygen species (ROS) on the Th17/Treg balance in CPP. The levels of ROS and the differentiation ratio of Th17/Treg in the peripheral blood of healthy individuals and CPP patients were measured using ELISA and flow cytometry, respectively. The association between the ROS levels and Th17/Treg was assessed using Pearson correlation analysis. The ROS levels and the Th17/Treg ratio were measured in CD4+ T cells following H2O2 treatment and NLRP3 inhibition. The effects of H2O2 treatment and NLRP3 inhibition on the NLRP3/IL-1ß/caspase-1 pathway were observed using immunoblotting. Compared to the healthy group, the CPP group exhibited increased levels of ROS in the peripheral blood, an elevated ratio of Th17 differentiation, and a decreased ratio of Treg differentiation. ROS levels were positively correlated with the Th17 cell proportion but negatively correlated with the Treg cell proportion. The ROS levels and NLRP3/IL-1ß/caspase-1 expression were up-regulated in CD4+ T cells after H2O2 treatment. Furthermore, there was an increase in Th17 differentiation and a decrease in Treg differentiation. Conversely, the NLRP3/IL-1ß/caspase-1 pathway inhibition reversed the effects of H2O2 treatment, with no significant change in the ROS levels. ROS regulates the Th17/Treg balance in CPP, possibly through the NLRP3/IL-1ß/caspase-1 pathway. This study provides a new perspective on the development of immunotherapy for CPP.

Associations of maternal liver biomarkers in the first trimester with the risk of hypertensive disorders of pregnancy.

This study aimed to evaluate the association between maternal liver biomarkers in early pregnancy and the risk of hypertensive disorders of pregnancy (HDP), as well as to evaluate interaction between liver enzymes and BMI on the development of HDP. Pregnant women in our study were recruited from the Zhoushan Pregnant Women Cohort. Participants who had their first prenatal follow-up and the blood pressure follow-up records, and measured liver biomarkers in the first trimester were eligible for inclusion in the study. A total of 10,610 pregnant women were included in the analysis, and 305 (2.87%) developed the HDP. There were positive associations between AST, GGT, ALP, HSI and SBP, as well as between ALT, GGT, ALP, HSI and DBP. In addition, AST/ALT level was negatively associated with DBP. The highest quartile of GGT, ALP, AST/ALT and HSI were significantly associated with 1.71-fold (95% Cl: 1.23-2.41), 1.53-fold (95% Cl: 1.10-2.14), 0.62-fold (95% Cl: 0.43-0.90) and 1.67-fold (95% Cl: 1.05-2.67) increased risk of HDP, respectively. There was no significant association between ALT, AST and HDP. These associations remained consistent in pregnant women with liver enzymes within the clinical reference range. Besides, we found an interaction between GGT and BMI (Pinteraction = 0.013) in the development of HDP. In summary, the level of GGT, ALP, AST/ALT and HSI were associated with the subsequent risk of HDP, even within the clinical reference range. And there was an interaction between liver biomarkers and BMI in the development of HDP. Our study showed the level of GGT, ALP, AST/ALT and HSI were associated with the subsequent risk of HDP. And there was an interaction between GGT and BMI in the risk of HDP.

Breastfeeding, Gestational Diabetes Mellitus, Size at Birth and Overweight/Obesity in Early Childhood.

Background: Breastfeeding appears to reduce the risk of childhood overweight/obesity. However, it remains unclear whether this protective effect persists among high-risk populations. This study aims to investigate the association of breastfeeding with the risk of overweight/obesity in early childhood and whether this association is altered by gestational diabetes mellitus (GDM) or size at birth. Methods: Feeding practices during the first 12 months of age and weight and length at 12-36 months of age were collected. Full breastfeeding includes exclusive and predominant breastfeeding. Children with body mass index (BMI) values greater than 1 standard deviation from the mean of sex- and age-specific BMI were classified as overweight/obese. Multiple generalized estimating equations models were applied to analyze the associations of full breastfeeding duration with overweight/obesity risk. Results: Among all participants (n = 9329), infants with a longer full-breastfeeding duration had a reduced risk of overweight/obesity in early childhood compared with those breastfed for less than one month. Infants exposed to GDM and those born large for gestational age (LGA) had a higher risk of overweight/obesity in early childhood. Among infants of mothers with GDM (n = 1748), infants with full breastfeeding for greater than 6 months (aOR: 0.58; 95% CI: 0.44, 0.78) showed a decreased risk of overweight/obesity in early childhood compared with those breastfed for less than one month. Among LGA infants (n = 1279), infants with full breastfeeding for 3-5 months (aOR: 0.66; 95% CI: 0.57, 0.76) and greater than 6 months (aOR: 0.70; 95% CI: 0.56, 0.88) showed a decreased risk of overweight/obesity in early childhood. Similar results were observed among LGA infants of mothers with GDM. Conclusions: Initiating and prolonging breastfeeding would reduce the risk of overweight/obesity in early childhood, and LGA infants and infants born to mothers with GDM would experience greater benefits.

Effect of iron saturation of bovine lactoferrin on the inhibition of hepatitis B virus in vitro.

Background: Hepatitis B virus (HBV) infection poses a major public health problem worldwide. Bovine lactoferrin (bLf) is a natural product that can inhibit HBV, but the effect of iron saturation on its resistance to HBV is unknown. Aims: The purpose of this study is to investigate the impact of iron saturation of bLf against HBV. Methods: HepG2 cells were cultured in DMEM high glucose containing 10% inactivated fetal calf serum, at 37 °C, in 5% CO2. MTT method was used to detect the cytotoxicity of bLf to HepG2 cells. Apo-bLf and holo-bLf were prepared from bLf. Iron saturation of these proteins was determined by atomic absorption spectrophotometry. Non-cytotoxic concentrations of candidate proteins were used in anti-HBV tests. Fluorescent quantitative polymerase chain reaction was used to detect HBV-DNA. Results: The TC50 and TC0of bLf were 54.570 mg/ml and 1.997 mg/ml, respectively. The iron saturation of bLf, apo-bLf and holo-bLf were 10.29%, 8.42% and 85.32%, respectively. In this study, four non-cytotoxic concentrations of candidate proteins (1.5, 1.0, 0.5, and 0.1 mg/ml, respectively) were used to inhibit HBV in HepG2 cells. The results showed that 1.5 mg/ml bLf and 0.1 mg/ml holo-bLf effectively impaired the HBV-DNA amplification in HBV-infected HepG2 cells (P < 0.05). However, apo-bLf, and Fe3+ did not show the anti-HBV effects. Conclusion: A total of 1.5 mg/ml bLf and 0.1 mg/ml holo-bLf could inhibit HBV-DNA in HepG2 cells. Complete bLf structure, appropriate concentration and iron saturation of bLf are necessary conditions for anti-HBV effects.

Association of systemic chronic inflammation during pregnancy in different periods and its trajectories with preterm birth.

PROBLEM: Systemic chronic inflammation (SCI) is a prevalent characteristic observed in various diseases originating from different tissues, while the association of SCI with preterm birth (PTB) remains uncertain. This study aimed to analyze the association between a nonspecific biomarker of SCI and PTB, while also exploring the trajectories of SCI in pregnant women at risk of PTB. METHOD OF STUDY: The study used data from the Electronic Medical Record System (EMRS) of a hospital in Zhejiang, China and 9226 pregnant women were included. The duration of pregnancy was categorized into four distinct periods: the first, early-second, late-second, and third trimester. Latent class trajectory modeling (LCTM) was used to identify the trajectories of SCI during pregnancy. RESULTS: The elevated WBC counts in the late-second (OR = 1.14, 95% CI: 1.06-1.23) and third (OR = 1.16, 95% CI: 1.09-1.24) trimester were both positively associated with an evaluated risk of PTB. Moreover, significant dose-response relationships were observed. There were three distinct SCI trajectories found: progressing SCI (2.89%), high SCI (7.13%), and low SCI (89.98%). Pregnant women with progressive SCI had the highest risk of PTB (OR = 3.03, 95% CI: 1.47-6.25). CONCLUSIONS: In conclusion, elevated SCI after 23 weeks was a risk factor for PTB in healthy women, even if the SCI indicator was within normal range. Pregnant women with progressive SCI during pregnancy had the highest risk of PTB.

Patient-Controlled Subcutaneous Analgesia with Hydromorphone versus Oral Oxycontin for Opioid Titration of Cancer Pain: A Prospective Multicenter Randomized Trial.

Background: Studies have shown that oral oxycontin tablets can be used for opioid titration. The European Society for Medical Oncology (ESMO) guidelines for adult cancer pain recommend opioid titration through the parenteral route, usually the intravenous or subcutaneous route. Patient-controlled subcutaneous analgesia (PCSA) with hydromorphone needs further evaluation for opioid titration. This prospective multicenter study was designed to compare the efficacy and safety of hydromorphone PCSA with oral oxycontin tablets for opioid titration of cancer pain. Patients and Methods: Eligible patients with cancer pain were randomly assigned in a 1:1 ratio to the PCSA group or the oxycontin group for dose titration. Different titration methods were given in both groups depending on whether the patient had an opioid tolerance. The primary endpoint of this study was time to successful titration (TST). Results: A total of 256 patients completed this study. The PCSA group had a significantly lower TST compared with the oxycontin group (median [95% confidence interval (CI)], 5.5[95% CI:2.5-11.5] hours vs.16.0 [95% CI:11.5-22.5] hours; p<0.001). The frequency (median; interquartile) of breakthrough pain (Btp) over 24 hours was significantly lower in the PCSA group (2.5;2.0-3.5) than in the oxycontin group.(3.0; 2.5-4.5) (p=0.04). The pain was evaluated by numeric rating scale (NRS) score at 12 hours after the start of titration. The pain score (median; interquartile) was significantly lower in the PCSA versus the oxycontin group (2.5;1.5-3.0) vs 4.5;3.0-6.0) (p=0.02). The equivalent dose of oral morphine (EDOM) for a successful titration was similar in both groups (p=0.29), but there was a significant improvement in quality of life (QoL) in both groups (p=0.03). No between-group difference in the incidence of opioid-related adverse effects was observed (p=0.32). Conclusion: Compared with oral oxycontin tablet, the use of PCSA with hydromorphone achieved a shorter titration duration for patients with cancer pain (p<0.001), without significantly increasing adverse events (p=0.32).

Generation of rat forebrain tissues in mice.

Interspecies blastocyst complementation (IBC) provides a unique platform to study development and holds the potential to overcome worldwide organ shortages. Despite recent successes, brain tissue has not been achieved through IBC. Here, we developed an optimized IBC strategy based on C-CRISPR, which facilitated rapid screening of candidate genes and identified that Hesx1 deficiency supported the generation of rat forebrain tissue in mice via IBC. Xenogeneic rat forebrain tissues in adult mice were structurally and functionally intact. Cross-species comparative analyses revealed that rat forebrain tissues developed at the same pace as the mouse host but maintained rat-like transcriptome profiles. The chimeric rate of rat cells gradually decreased as development progressed, suggesting xenogeneic barriers during mid-to-late pre-natal development. Interspecies forebrain complementation opens the door for studying evolutionarily conserved and divergent mechanisms underlying brain development and cognitive function. The C-CRISPR-based IBC strategy holds great potential to broaden the study and application of interspecies organogenesis.

Multidimensional Criteria for Virtual Screening of PqsR Inhibitors Based on Pharmacophore, Docking, and Molecular Dynamics.

Pseudomonas aeruginosa is a clinically challenging pathogen due to its high resistance to antibiotics. Quorum sensing inhibitors (QSIs) have been proposed as a promising strategy to overcome this resistance by interfering with the bacterial communication system. Among the potential targets of QSIs, PqsR is a key regulator of quorum sensing in Pseudomonas aeruginosa. However, the current research on PqsR inhibitors is limited by the lack of diversity in the chemical structures and the screening methods. Therefore, this study aims to develop a multidimensional screening model for PqsR inhibitors based on both ligand- and receptor-based approaches. First, a pharmacophore model was constructed from a training set of PqsR inhibitors to identify the essential features and spatial arrangement for the activity. Then, molecular docking and dynamics simulations were performed to explore the core interactions between PqsR inhibitors and their receptor. The results indicate that an effective PqsR inhibitor should possess two aromatic rings, one hydrogen bond acceptor, and two hydrophobic groups and should form strong interactions with the following four amino acid residues: TYR_258, ILE_236, LEU_208, and GLN_194. Moreover, the docking score and the binding free energy should be lower than -8 kcal/mol and -40 kcal/mol, respectively. Finally, the validity of the multidimensional screening model was confirmed by a test set of PqsR inhibitors, which showed a higher accuracy than the existing screening methods based on single characteristics. This multidimensional screening model would be a useful tool for the discovery and optimization of PqsR inhibitors in the future.

Inhaled endotoxin induces a systemic neutrophil response without affecting cardiovascular measures in a randomized cross-over exposure study.

OBJECTIVE: The gram-negative bacterial cell wall component endotoxin (lipopolysaccharide, LPS) is a key component of particulate matter (PM). PM exposure is associated with cardiovascular morbidity and mortality. However, the contribution of individual components of PM to acute and chronic cardiovascular measures is not clear. This study examines whether systemic inflammation induced by LPS inhalation causes acute changes in cardiovascular physiology measures. MATERIALS AND METHODS: In this double blinded, placebo-controlled crossover study, fifteen adult volunteers underwent inhalation exposure to 20,000 EU Clinical Center Reference Endotoxin (CCRE). Peripheral blood and induced sputum neutrophils were obtained at baseline and six hours post-exposure. Blood pressure, measures of left ventricular function (ejection fraction (LVEF) and global longitudinal strain (LVGLS)), and indices of endothelial function (flow mediated dilation (FMD) and velocity time integral during hyperemia (VTIhyp)) were measured before and after treatment. Wilcoxon sign-rank tests and linear mixed models were used for statistical analysis. RESULTS: In comparison with normal saline, LPS inhalation resulted in significant increases in peripheral blood and sputum neutrophils but was not associated with significant alterations in blood pressure, LVGLS, LVEF, FMD, or VTIhyp. DISCUSSION AND CONCLUSIONS: In healthy adults, systemic inflammation after LPS inhalation was not associated with acute changes in cardiovascular physiology. Larger studies are needed to investigate the effects of other PM components on inflammation induced cardiovascular dysfunction.

Drug-loaded lipid nanoparticles improve the removal rates of the Staphylococcus aureus biofilm.

Biofilms of the foodborne pathogen Staphylococcus aureus show improved resistance to antibiotics and are difficult to eliminate. To enhance antibacteria and biofilm dispersion via extracellular matrix diffusion, a new lipid nanoparticle was prepared, which employed a mixture of phospholipids and a 0.8% surfactin shell. In the lipid nanoparticle, 31.56 µg mL-1 of erythromycin was encapsulated. The lipid nanoparticle size was approximately 52 nm and the zeta-potential was -67 mV, which was measured using a Marvin laser particle size analyzer. In addition, lipid nanoparticles significantly dispersed the biofilms of S. aureus W1, CICC22942, and CICC 10788 on the surface of stainless steel, reducing the total viable count of bacteria in the biofilms by 103 CFU mL-1 . In addition, the lipid nanoparticle can remove polysaccharides and protein components from the biofilm matrix. The results of laser confocal microscopy showed that the lipid nanoparticles effectively killed residual bacteria in the biofilms. Thus, to thoroughly eliminate biofilms on material surfaces in food factories to avoid repeated contamination, drug-lipid nanoparticles present a suitable method to achieve this.

Massive hemoptysis in pregnancy treated by ECMO combined with electronic bronchoscopy: A case report.

Background: Massive hemoptysis during pregnancy is very rare. Dieulafoy's disease is one of the causes of massive hemoptysis. There are few reports of ECMO use to treat massive hemoptysis during pregnancy. Findings: We report for the first time a patient with Dieulafoy's disease diagnosed at 29 weeks of pregnancy. The patient's hemoptysis occurred rapidly with large volumes. The bleeding amount reached 500 ml within half an hour, with the development of asphyxia and respiratory and cardiac arrest due to a blood clot blocking the airway. After successful cardiopulmonary resuscitation, the ventilator could not maintain effective ventilation. Emergency establishment of VV-ECMO was performed to maintain oxygen, and hemostasis was successfully achieved by performing bronchial artery embolization twice. We successfully cleaned blood clots in the airway four times by freezing and using a foreign body retrieval basket with an electronic bronchoscope. At the same time, small and smooth nodular lesions were found under bronchoscopy, and blood vessels with a diameter of 1.5 mm were found under Doppler mode with an ultrasonic bronchoscope, which was consistent with a diagnosis of Dieulafoy's disease. VV-ECMO was successfully stopped on the 3rd day of the disease course, tracheal intubation was successfully removed on the 5th day of the disease course, and the patient was discharged with no complications on the 16th day of the disease course.