Transcatheter arterial embolization with N-butyl cyanoacrylate for postoperative hemorrhage treatment following pancreatoduodenectomy.

PURPOSE: Postoperative hemorrhage (PPH) is a severe complication of pancreatoduodenectomy (PD) with a mortality rate of 5-20.2% and mortality due to hemorrhage of 11-58%. Transcatheter arterial embolization (TAE) has been widely recommended for PPH, however, TAE with N-butyl cyanoacrylate (NBCA) for PPH treatment has been reported rarely. Therefore, this study aimed to evaluate the safety and efficacy of TAE with NBCA for PPH treatment following PD. METHODS: This retrospective study included 14 male patients (mean age, 60.93 ± 10.97 years) with postoperative hemorrhage following PD treated with TAE using NBCA as the main embolic agent from October 2019 to February 2022. The clinical data, technical and success rate, and complications were analyzed. RESULTS: Among the 14 patients who underwent TAE, the technical and clinical success rates were 100 and 85.71%, respectively. Angiography revealed contrast extravasation in 12 cases and a pseudoaneurysm in 3 cases. One patient developed a serious infection and died 2 days after the TAE. CONCLUSION: TAE with NBCA for PPH treatment following PD, especially for massive hemorrhage caused by a pancreatic fistula, biliary fistula, or inflammatory corrosion, can result in rapid and effective hemostasis with high safety.

Long-term outcomes of transarterial embolization with lipiodol-bleomycin emulsion plus polyvinyl alcohol particles versus the particles alone for large symptomatic focal nodular hyperplasia: a propensity score-matched analysis.

OBJECTIVES: To compare the efficacy of transarterial embolization (TAE) with polyvinyl alcohol (PVA) particles alone and lipiodol-bleomycin emulsion (LBE) plus PVA particles for patients with unresectable large symptomatic focal nodular hyperplasia (FNH). METHODS: We performed a retrospective analysis of patients who underwent TAE either with PVA particles alone (group A, n = 46) or LBE plus PVA particles (group B, n = 35) for large (≥ 7 cm) symptomatic FNH between January 2002 and February 2019. Propensity score matching (PSM) (1:1) was performed to adjust for potential baseline confounders. Technical success, adverse events (AEs), symptom relief, and changes in the lesion size after TAE were evaluated. Statistical analysis included Wilcoxon rank sum test and χ2 test. RESULTS: After PSM, no significant differences in baseline characteristics were found between the groups (31 in group A and 31 in group B, with a mean age of 31 years). Technical success was achieved in all patients (100%), without major AEs in both groups. Complete resolution of the abdominal symptoms was reported in 77.4% in group A and 100% in group B (p = 0.037) during a mean follow-up period of 72 months; complete resolution (CR) of the FNH rate was significantly higher in group B than in group A (93.6% vs. 67.7%; p = 0.019). CONCLUSION: Compared with the use PVA particles alone, TAE with LBE plus PVA particles in the treatment of patients with large symptomatic FNH had a significantly higher rates of CR of the FNH and complete relief of the symptoms. KEY POINTS: • Transarterial embolization (TAE) with lipiodol-bleomycin emulsion (LBE) plus PVA particles for the large symptomatic FNH yielded better results than with PVA particles alone, in terms of complete resolution of FNH lesions (93.6% vs 67.7%) and complete relief of the abdominal symptoms (100% vs 77.4%) during a mean follow-up period of 72 months (38-170 months). • No major complications were recorded in both groups, and no significant difference in the incidence of postembolization syndrome were observed between the two groups.

Lipid-specific interactions determine the organization and dynamics of membrane-active peptide melittin.

The cell membranes of different cells deviate significantly in lipid compositions and thus provide varying biological environments to modulate the diffusion, organization and the resultant function of biomacromolecules. However, the detailed modulation mechanism remains elusive especially in consideration of the current overuse of the simplified membrane models such as the pure phosphatidylcholine (PC) membrane. In this work, with the typical membrane-active peptide melittin, we demonstrated that a more complicated membrane environment, such as the bacterial (IME) or plasma membrane (PM), would significantly change the organization and dynamics of melittin, by using molecular dynamics simulations as a "computational microscope". It was found that in these membrane systems, adding melittin would cause a varying degree of reduction in the lateral diffusion of lipids due to the different assembly states of peptides. Melittin tended to aggregate to oligomers in the pure PC membrane, mostly as a tetramer or trimer, while in IME or PM, its degree of oligomerization was significantly reduced. More surprisingly, melittin displayed a strong affinity with ganglioside GM3 in PM, leading to the formation of melittin-GM3 nanoclusters, which hindered its diffusion and further oligomerization. Additionally, small changes in the residue sequence of melittin could modulate the degree or structure of the peptide oligomer. Our work provides a typical example of a study on the organization and dynamics of pore-forming peptides in specific membrane environments and has great significance on the optimization of peptide sequences and the design of helix bundles in the membrane for target biological function.

Single-cell analysis reveals the relevance of foot-and-mouth disease virus persistence to emopamil-binding protein gene expression in host cells.

Foot-and-mouth disease virus (FMDV) infects host cells in either an acute or persistent manner. In this study, we examined the relevance of the establishment of FMDV persistence to the expression of the emopamil-binding protein (EBP) gene in 231 individual persistently infected baby hamster kidney (BHK-21) cells after passages 28, 38, and 68 (PI28, PI38, and PI68). At PI28, the stage at which persistent infection of FDMV becomes unstable, the percentage of cells carrying FMDV was 66.7%, while 80.2% of cells were EBP positive. Additionally, in 55.6% of the EBP-positive cells at PI28, EBP expression was upregulated approximately 149.9% compared to uninfected BHK-21 cells. This was the highest expression level among all cell passages measured. Interestingly, in a parallel experiment, the average EBP expression level in the whole cell population at PI28 was only slightly higher (108.2%) than that in uninfected BHK-21 cells. At PI38, 98.7% of the cells were positive for FMDV 3D (an RNA-dependent RNA polymerase enzyme gene), and its maximum expression level observed at this passage. The expression level of EBP in 78.2% of the total cells, however, was reduced significantly. At PI68, 95.8% of the cells were 3D positive, and the expression of both the EBP and 3D genes were at the lowest levels of all the passages. Our studies using single cells yielded data that are otherwise inaccessible a using whole cell population. These results suggest that the establishment of persistent infection by FMDV is a dynamic process that results from the continuous adaptation and coevolution of viruses and cells to reach an equilibrium.

Reduced graphene oxide directed self-assembly of phospholipid monolayers in liquid and gel phases.

The response of cell membranes to the local physical environment significantly determines many biological processes and the practical applications of biomaterials. A better understanding of the dynamic assembly and environmental response of lipid membranes can help understand these processes and design novel nanomaterials for biomedical applications. The present work demonstrates the directed assembly of lipid monolayers, in both liquid and gel phases, on the surface of a monolayered reduced graphene oxide (rGO). The results from atomic force microscopy indicate that the hydrophobic aromatic plane and the defect holes due to reduction of GO sheets, along with the phase state and planar surface pressure of lipids, corporately determine the morphology and lateral structure of the assembled lipid monolayers. The DOPC molecules, in liquid phase, probably spread over the rGO surface with their tails associating closely with the hydrophobic aromatic plane, and accumulate to form circles of high area surrounding the defect holes on rGO sheets. However, the DPPC molecules, in gel phase, prefer to form a layer of continuous membrane covering the whole rGO sheet including defect holes. The strong association between rGO sheets and lipid tails further influences the melting behavior of lipids. This work reveals a dramatic effect of the local structure and surface property of rGO sheets on the substrate-directed assembly and subsequent phase behavior of the supported lipid membranes.

Expression of porcine Mx1 with FMDV IRES enhances the antiviral activity against foot-and-mouth disease virus in PK-15 cells.

Foot-and-mouth disease virus (FMDV) is the most contagious pathogen in cloven-hoofed (two-toed) animals. Due to the rapid replication and spread of FMDV, novel therapeutic strategies are greatly needed to reduce or block FMDV shedding in cases of disease outbreak. Here, we generated an IRES-Mx1 construct in which the internal ribosome entry site (IRES) of FMDV was inserted between the promoter and open reading frame (ORF) of porcine myxovirus resistance protein 1 (poMx1). This construct provides more powerful protection against FMDV infection than the IRES-IFN construct that was previously generated by our group. The results indicate that this IRES-Mx1 construct was able to express poMx1 12 h after transfection and induce a robust immune response. In contrast to the control, the proliferation of virus in transfected cells was significantly inhibited, as evaluated by morphology monitoring, real-time RT-PCR, virus titration and Western blot. In addition, we also found that the antiviral activity in cells transfected with pc-IRES-Mx1 was abolished when the JAK/STAT pathway was repressed, which indicates that the antiviral mechanism of poMx1 is JAK/STAT pathway dependent. Taken together, our data suggest that the antiviral activity of poMx1 is possibly produced by affecting the host cells themselves, instead of interacting with the virus directly. The new construct reported here could be used as a novel effective therapy against FMDV infection.

Vesicle deposition and subsequent membrane-melittin interactions on different substrates: a QCM-D experiment.

Quartz crystal microbalance with dissipation (QCM-D) technique is one of the most effective methods to monitor the dynamic behaviors of a layer on a solid surface. Moreover, it has been reported recently that it is able to provide a fingerprint for the peptide-membrane interactions. In this work, QCM-D technique combined with computer simulations was employed to investigate the deposition and transformation of vesicles, as well as the subsequent membrane-melittin interactions on different substrates. A range of substrate surfaces, i.e. naked SiO2 without or with Au/polyelectrolyte coating, were produced. The nature of the substrate determined whether the adsorbed vesicles were present as a high-quality supported bilayer or an assembled vesicle matrix, which consequently influenced the membrane-melittin interactions. It was indicated by the related computer simulations that the lipid packing state of the membrane was a key factor to determine the mechanism of membrane-peptide interactions. Furthermore, this work might be a good example of the application of QCM-D for the exploration of membrane-active peptides.

Influence of surface chemistry on particle internalization into giant unilamellar vesicles.

Cellular uptake of materials plays a key role in their biomedical applications. In this work, based on the cell-mimic giant unilamellar vesicles (GUVs) and a novel type of microscale materials consisting of stimuli-responsive poly(N-isopropylacrylamide) microgel particles and the incorporated lipids, the influence of particle surface chemistry, including hydrophobic/hydrophilic property and lipid decorations, on the adsorption and consequent internalization of particles into GUVs was investigated. It is found that the decoration of particle surface with lipids facilitates the adsorption of particles on GUV membrane. After that, the hydrophobic property of particle surface further triggers the internalization of particles into GUVs. These results demonstrate the importance of surface properties of particles on their interactions with lipid membranes and are helpful to the understanding of cellular uptake mechanism.

Outcomes of transarterial embolization for large symptomatic focal nodular hyperplasia in 17 pediatric patients.

BACKGROUND: To evaluate the safety and the long-term outcomes of transarterial embolization (TAE) with lipiodol-bleomycin emulsion (LBE) plus N-Butyl cyanoacrylate (NBCA) in the treatment of children with large symptomatic focal nodular hyperplasia (FNH). METHODS: This is a retrospective case serial study. Children (aged <18 years) with FNH were treated. Indications for TAE were patients who were presenting with FNH related abdominal pain and the maximum diameter of FNH is more than 7 cm, and who were not candidates for surgical treatment. Technical success, adverse events, symptoms relief rate, and changes in the lesion size after TAE were evaluated. RESULTS: Between January 2003 and February 2018, 17 pediatric patients were included. Technical success was achieved in all patients. Mean follow-up was 67.5 months. All patients had complete resolution of abdominal symptom. The mean largest diameter of the lesions decreased from 10.5 cm to 1.9 cm (P < 0.01). The mean volume reduction rate was 96.9%. The complete resolution of the FNH was observed in 16 patients. No further therapy was needed for all patients. CONCLUSIONS: TAE with LBE plus NBCA appears to be a safe and effective treatment in pediatric patients with large symptomatic FNH. It could be considered as the first-line treatment for symptomatic large FNH.

Membrane-Specific Binding of 4 nm Lipid Nanoparticles Mediated by an Entropy-Driven Interaction Mechanism.

Lipid nanoparticles (LNPs) are a leading biomimetic drug delivery platform due to their distinctive advantages and highly tunable formulations. A mechanistic understanding of the interaction between LNPs and cell membranes is essential for developing the cell-targeted carriers for precision medicine. Here the interactions between sub 10 nm cationic LNPs (cLNPs; e.g., 4 nm in size) and varying model cell membranes are systematically investigated using molecular dynamics simulations. We find that the membrane-binding behavior of cLNPs is governed by a two-step mechanism that is initiated by direct contact followed by a more crucial lipid exchange (dissociation of cLNP's coating lipids and subsequent flip and intercalation into the membrane). Importantly, our simulations demonstrate that the membrane binding of cLNPs is an entropy-driven process, which thus enables cLNPs to differentiate between membranes having different lipid compositions (e.g., the outer and inner membranes of bacteria vs the red blood cell membranes). Accordingly, the possible strategies to drive the membrane-targeting behaviors of cLNPs, which mainly depend on the entropy change in the complicated entropy-enthalpy competition of the cLNP-membrane interaction process, are investigated. Our work unveils the molecular mechanism underlying the membrane selectivity of cLNPs and provides useful hints to develop cLNPs as membrane-targeting agents for precision medicine.

A real-time and in-situ monitoring of the molecular interactions between drug carrier polymers and a phospholipid membrane.

The dynamic interactions between drug carrier molecules and a cell membrane can not be ignored in their clinical use. Here a simple, label-free and non-invasive approach, photo-voltage transient method, combined with the atomic force microscopy, dynamic giant unilamellar vesicle leakage assay and cytotoxicity method, was employed for a real-time monitoring of the interaction process. Two representative polymer molecules, polyoxyethylene (35) lauryl ether (Brij35) and polyvinylpyrrolidone (PVPk30), were taken as examples to interact with a phospholipid bilayer membrane in a low ionic strength and neutral pH condition. Brij35 demonstrated an adsorption-accumulation-permeabilization dominated process under the modulation of polymer concentration in the solution. In contrast, PVPk30 performed a dynamic balance between adsorption-desorption of the molecules and/or permeabilization-resealing of the membrane. Such difference explains the high and low cytotoxicity of them, respectively, in the living cell tests. Briefly, through combining the photo-voltage approach with conventional fluorescent microscopy method, this work demonstrates new ideas on the time and membrane actions of polymer surfactants which should be taken into account for their biomedical applications.

Correlation between Single-Molecule Dynamics and Biological Functions of Antimicrobial Peptide Melittin.

Many fundamental biological processes occur on cell membranes, and a typical example is the membrane permeabilization by peptides for an antimicrobial purpose. Previous studies of the underlying mechanism mostly focus on structural changes of membranes and peptides during their interactions. Herein, from a new perspective of single-molecule dynamics, the real-time three-dimensional motions of individual phospholipid and peptide molecules were monitored, and specifically, their correlation with the membrane poration function of melittin, a most representative natural antimicrobial peptide, was studied. We found that the adsorption and accumulation of melittin on the membrane surface significantly sped up the lateral diffusion of lipids surrounding the peptides, which in turn facilitated the peptide insertion at such heterogeneous regions. A unique "U"-bending pathway of melittin during membrane insertion and the ultimate formation of toroidal pores with dynamical translocations of peptides and lipids with several metastable states between the two leaflets of bilayer were observed.

[Effect of impact direction on the cushion property of mouthguards: a finite element analysis].

PURPOSE: The aim of this study was to evaluate the cushion property of mouthguards when the impact object came from different directions. METHODS: A 3D finite element model of upper central incisor, periodontal ligament and alveolar bone was developed based on cone-beam CT (CBCT) images of a plastic teeth model. The mouthguards were modeled in 5 different thickness (T: 0, 1.5, 3, 4.5 and 6 mm) and a nonlinear dynamic impact analysis, in which the finite element models were collided by a steel ball from different directions (D: angles between the impact direction and the long axis of tooth were 30°, 60°, 90°, 120°, respectively), was performed. The stress cushion efficiency was calculated. RESULTS: The stress cushion efficiency of the mouthguards varied with different thicknesses and impact directions. When T=1.5 mm and 3 mm, the stress cushion efficiency was minimal as D=60° and maximal as D=120°. However, when T=4.5 mm and 6 mm, the stress cushion efficiency was minimal as D=90° and maximal as D=30°. Moreover, the stress cushion efficiency of mouthguards improved with the increasing thickness in each impact direction. CONCLUSIONS: The impact direction affects the stress cushion efficiency of mouthguards, which however is influenced by the thickness of mouthguards.

Controlled drug loading and release of a stimuli-responsive lipogel consisting of poly(N-isopropylacrylamide) particles and lipids.

Environmentally responsive materials are attractive for advance biomedicine applications such as controlled drug delivery and gene therapies. Recently, we have introduced the fabrication of a novel type of stimuli-sensitive lipogel composite consisting of poly(N-isopropylacrylamide) (pNIPAM) microgel particles and lipids. In this study, we demonstrated the temperature-triggered drug release behavior and the tunable drug loading and release capacities of the lipogel. At room temperature (22 °C), no calcein was released from the lipogel over time. At body temperature (37 °C), the release process was significantly promoted; lipids in the lipogel acted as drug holders on the pNIPAM scaffold carrier and prolonged the calcein release process from 10 min to 2 h. Furthermore, the loading and release of calcein could be effectively controlled by modulating the relative amount of lipids incorporated in the lipogel, which can be realized by the salt-induced lipid release of the lipogel.

Expression of exogenous IFN-alpha by bypassing the translation block protects cells against FMDV infection.

Foot-and-mouth disease virus (FMDV) is the most contagious pathogen of cloven-hoofed animals. Previous studies have demonstrated that type I interferons [alpha/beta interferons (IFN-alpha/betas)] can suppress FMDV replication and spread. Conversely, FMDV can also inhibit IFN-alpha expression in infected cells by blocking cap-dependent translation. To overcome the blockade on IFN-alpha mRNA translation during FMDV infection, we generated an IRES-IFN construct that carries FMDV's internal ribosome entry site (IRES) cDNA sequence between the promoter and porcine IFN-alpha gene. ELISA assays indicated that expression of IFN-alpha regulated by wild-type IRES increased to 125% of pre-infection level after infection for 24h, but the expression of IFN-alpha regulated by nonfunctional IRES mutants were only approximately 50% of pre-infection level. Correspondingly, the former could suppress the replication of FMDV to 20% of the latter and protect cells against FMDV for a longer time. Therefore, these findings provide a new strategy to anti-FMDV therapy.