Delivery of Suramin as an Antiviral Agent through Liposomal Systems

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No cupid, just an arrow : a penetrating injury into the interventricular septum

BackgroundPenetrating cardiac injuries are rare but often fatal, with 16-55% mortality. We report a patient who suffered a non-fatal occupational cardiac injury.Case presentationA 47-year-old man was operating an ironworker machine. A thin 3-cm metal fragment catapulted from the machine piercing the chest wall and the right ventricular outflow tract (RVOT), burrowing into the interventricular septum (IVS). The patient remained hemodynamically stable and walked to the nearest hospital. ECG-gated computed tomography revealed the exact location of the fragment within the IVS, allowing for detailed preoperative planning. The fragment was removed through a sternotomy and an incision through the RVOT. The postoperative course was uneventful.ConclusionsThis case underscores the value of detailed preoperative imaging and the wide spectrum of clinical scenarios of penetrating cardiac injuries.Peer reviewe

ATP requirements and small interfering RNA structure in the RNA interference pathway

We examined the role of ATP in the RNA interference (RNAi) pathway. Our data reveal two ATP-dependent steps and suggest that the RNAi reaction comprises at least four sequential steps: ATP-dependent processing of double-stranded RNA into small interfering RNAs (siRNAs), incorporation of siRNAs into an inactive approximately 360 kDa protein/RNA complex, ATP-dependent unwinding of the siRNA duplex to generate an active complex, and ATP-independent recognition and cleavage of the RNA target. Furthermore, ATP is used to maintain 5\u27 phosphates on siRNAs. A 5\u27 phosphate on the target-complementary strand of the siRNA duplex is required for siRNA function, suggesting that cells check the authenticity of siRNAs and license only bona fide siRNAs to direct target RNA destruction

Protein Fibrillar Hydrogels for three-Dimensional Tissue Engineering

Protein self-assembly into highly ordered fibrillar aggregates has attracted increasing attention over recent years, due primarily to its association with disease states such as Alzheimer's. More recently, however, research has focused on understanding the generic behavior of protein self-assembly where fibrillation is typically induced under harsh conditions of low pH and/or high temperature. Moreover the inherent properties of these fibrils, including their nanoscale dimension, environmental responsiveness, and biological compatibility, are attracting substantial interest for exploiting these fibrils for the creation of new materials. Here we will show how protein fibrils can be formed under physiological conditions and their subsequent gelation driven using the ionic strength of cell culture media while simultaneously incorporating cells homogeneously throughout the gel network. The fibrillar and elastic nature of the gel have been confirmed using cryo-transmission electron microscopy and oscillatory rheology, respectively; while cell culture work shows that our hydrogels promote cell spreading, attachment, and proliferation in three dimensions

Self-Assembled Structures in Diblock Copolymers with Hydrogen-Bonded Amphiphilic Plasticizing Compounds

Hydrogen-bonding amphiphilic low molecular weight plasticizing compounds to one block of diblock copolymers to form supramolecular comblike blocks leads to hierarchical self-assembly at the block copolymer (long) and amphiphile (short) length scales, in which lamellar-in-lamellar order and the related phase transitions have previously been shown to allow thermal switching of electrical and optical properties. In this work other hierarchies and phase transitions are systematically searched, a particular interest being hierarchies containing gyroid structures and the related order-order transitions. Polymeric supramolecular comb-coil diblock copolymers consisting of a polystyrene (PS) coillike block and a supramolecular comblike block based on poly(4-vinylpyridine) (P4VP) are used, where the pyridines are either directly hydrogen bonded with 3-pentadecylphenol (PDP), i.e., PS-block-P4VP(PDP)1.0, or first protonated with methanesulfonic acid (MSA) and then hydrogen bonded to PDP, i.e., PS-block-P4VP(MSA)1.0(PDP)1.0. In this way the comblike block can be noncharged or charged. The morphologies were determined using transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) at different temperatures. In the case of PS-block-P4VP(PDP)1.0, all classical diblock copolymer morphologies were observed at room temperature, where the P4VP(PDP)1.0 domains contain an additional lamellar structure due to the supramolecular comblike blocks. Here we report novel gyroid and hexagonal perforated layer morphologies, i.e., where the PS and P4VP(PDP)1.0 blocks form gyroid or hexagonal perforated layer order and the P4VP(PDP)1.0 domains have an internal lamellar order. Heating past ca. T = 60 °C causes an order-disorder transition within the P4VP(PDP)1.0 domains. Further heating leads to gradually reduced hydrogen bonding strength, and importantly PDP becomes soluble in PS at T > ca. 120 °C. At such temperatures PDP is found in both the P4VP and PS domains, thus leading to changes in the relative volume fractions of the domains, which in turn leads to order-order transitions. In PS-block-P4VP(MSA)1.0(PDP)1.0, typically lamellar and cylindrical block copolymeric structures were observed, where there was an additional internal lamellar order within the P4VP(MSA)1.0(PDP)1.0 domains. Coincidentally, an order-disorder transition within the P4VP(MSA)1.0(PDP)1.0 domains takes place at T = ca. 125 °C. Above that temperature, PDP is in both PS and P4VP(MSA)1.0 domains, but most interestingly at ca. T > 175 °C PDP becomes a nonsolvent for P4VP(MSA)1.0 and it is therefore expelled to predominantly to the PS domains. This manifests as an order-order transition. All samples exhibit at least two thermoreversible order-order transitions, and some of them show even five consecutive self-assembled phases as a function of temperature. Besides being amphiphilic, PDP can also be regarded as a plasticizer, i.e., relatively nonvolatile solvent, for the P4VP, PS, and P4VP(MSA)1.0 with characteristic phase behaviors. This, in combination with the comb-coil diblock copolymer composition and the reversibility of the hydrogen bonding, enables to achieve thermoreversible transition sequences that are not easily accessible only by changing the Flory-Huggins interaction parameter χ by temperature, for example transitions from a lamellar to spherical structure. The combination of phase behaviors of self-assembly and polymer/plasticizer mixtures allows new structural hierarchies and phase transitions that may lead to new types of responsive materials.

Functional Porous Structures Based on the Pyrolysis of Cured Templates of Block Copolymer and Phenolic Resin

Porous materials with controlled pore size and large surface area (see Figure) have been prepared by crosslinking phenolic resin in the presence of a self-assembled block-copolymer template, followed by pyrolysis. Many phenolic hydroxyl groups remain at the matrix and pore walls, which can be used for selective and efficient absorption or further functionalization

Efficacy and safety of the Lotus Valve System for treatment of patients with severe aortic valve stenosis and intermediate surgical risk: Results from the Nordic Lotus-TAVR registry

Peer reviewe

Towards Internal Structuring of Electrospun Fibers by Hierarchical Self-Assembly of Polymeric Comb-Shaped Supramolecules

Polystyrene-block-poly(4-vinylpyridine) with nominally one pentadecylphenol molecule hydrogen-bonded to each pyridine group has been electrospun, leading to fibers with a hierarchical, structure-within-structure morphology (see Figure). An internal structure on the nanometer length scale exists within a structure on the tens-of-manometers length scale. Internal porosity can be obtained by selective removal of the amphiphile