Evaluation of the in vitro differential protein adsorption patterns of didanosine-loaded nanostructured lipid carriers (NLCs) for potential targeting to the brain

The preferential in vitro adsorption of apolipoprotein E (Apo E) onto the surface of colloidal drug carriers may be used as a strategy to evaluate the in vivo potential for such systems to transport drugs to the brain. The aim of this research was to investigate the in vitro protein adsorption patterns of didanosine-loaded nanostructured lipid carriers (DDI-NLCs), using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), in order to establish the potential for NLCs to deliver DDI to the brain. NLC formulations were manufactured using high-pressure homogenization using a lipid matrix consisting of a mixture of Precirol® ATO 5 and Transcutol® HP. The 2-D PAGE analysis revealed that NLCs in formulations stabilized using Solutol® HS 15 alone or with a ternary surfactant system consisting of Solutol® HS 15, Tween® 80, and Lutrol® F68, preferentially adsorbed proteins, such as Apo E. Particles stabilized with Tween® 80 and Lutrol® F68 did not adsorb Apo E in these studies, which could be related to the relatively large particle size and hence small surface area observed for these NLCs. These findings have revealed that DDI-loaded NLCs may have the potential to deliver DDI to the brain in vivo and, in addition, to Tween® 80, which has already been shown to have the ability to facilitate the targeting of colloidal drug delivery systems to the brain. Solutol® HS 15–stabilized nanoparticles may also achieve a similar purpose

The F0F1-ATP Synthase Complex Contains Novel Subunits and Is Essential for Procyclic Trypanosoma brucei

The mitochondrial F0F1 ATP synthase is an essential multi-subunit protein complex in the vast majority of eukaryotes but little is known about its composition and role in Trypanosoma brucei, an early diverged eukaryotic pathogen. We purified the F0F1 ATP synthase by a combination of affinity purification, immunoprecipitation and blue-native gel electrophoresis and characterized its composition and function. We identified 22 proteins of which five are related to F1 subunits, three to F0 subunits, and 14 which have no obvious homology to proteins outside the kinetoplastids. RNAi silencing of expression of the F1 α subunit or either of the two novel proteins showed that they are each essential for the viability of procyclic (insect stage) cells and are important for the structural integrity of the F0F1-ATP synthase complex. We also observed a dramatic decrease in ATP production by oxidative phosphorylation after silencing expression of each of these proteins while substrate phosphorylation was not severely affected. Our procyclic T. brucei cells were sensitive to the ATP synthase inhibitor oligomycin even in the presence of glucose contrary to earlier reports. Hence, the two novel proteins appear essential for the structural organization of the functional complex and regulation of mitochondrial energy generation in these organisms is more complicated than previously thought

Protein Adsorption Patterns and Analysis on IV Nanoemulsions—The Key Factor Determining the Organ Distribution

Intravenous nanoemulsions have been on the market for parenteral nutrition since the 1950s; meanwhile, they have also been used successfully for IV drug delivery. To be well tolerable, the emulsions should avoid uptake by the MPS cells of the body; for drug delivery, they should be target-specific. The organ distribution is determined by the proteins adsorbing them after injection from the blood (protein adsorption pattern), typically analyzed by two-dimensional polyacrylamide gel electrophoresis, 2-D PAGE. The article reviews the 2-D PAGE method, the analytical problems to be faced and the knowledge available on how the composition of emulsions affects the protein adsorption patterns, e.g., the composition of the oil phase, stabilizer layer and drug incorporation into the interface or oil core. Data were re-evaluated and compared, and the implications for the in vivo distribution are discussed. Major results are that the interfacial composition of the stabilizer layer is the main determining factor and that this composition can be modulated by simple processes. Drug incorporation affects the pattern depending on the localization of the drug (oil core versus interface). The data situation regarding in vivo effects is very limited; mainly, it has to be referred to in the in vivo data of polymeric nanoparticles. As a conclusion, determination of the protein adsorption patterns can accelerate IV nanoemulsion formulation development regarding optimized organ distribution and related pharmacokinetics

In vitro protein adsorption studies on nevirapine nanosuspensions for HIV/AIDS chemotherapy

Nevirapine is a poorly water-soluble antiretroviral drug. Intravenous nevirapine nanosuspensions (NS) (457 ± 10 nm) were prepared by high-pressure homogenization. NS were surface modified by stabilizer adsorption, e.g., serum albumin, polysaccharide and polyethylene glycol (PEG) 1000. The NS were characterized for mean particle size, particle size distribution and polydispersity index. The targeting potential of the nonmodified and three surface-modified NS to the mononuclear phagocytic system (MPS) cells that serve as potent viral reservoirs was assessed by in vitro protein adsorption studies using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). The adsorption patterns were qualitatively identical, but showed quantitative differences. The relatively adsorbed high amounts of immunoglobulins indicate uptake by liver and spleen, observed quantitative differences (e.g., the amount of dysopsonin albumin and apolipoproteins) can modulate the organ distribution. Controlled in vitro optimization of the protein adsorption by surface modification of the nanocrystals can reduce the number of animals required for in vivo studies and accelerate development of targeted nanoparticles

MONITORING AND DEFORMATION ANALYSIS OF GROYNES USING TLS AT THE RIVER ELBE

To enter the Port of Hamburg, one of Europe’s busiest ports all vessels need to navigate around 145 km along the Elbe river, a tide influenced navigation channel. To protect the Elbe shoreline from erosion and to channel the waterway groynes (rigid hydraulic structures) have been built along the river. In the past years since ca. 2001 there has been a large increase in damage of groynes structural integrity at parts of the German waterways. The reason for this was determined in the ever growing size of container vessels passing by and inducing long periodical primary waves which have such a force that they erode the groynes rock structure. To analyse and improve the groynes structural resistance for vessel-induced long periodical wave loads an in-situ study is carried out at Juelssand, located at the Elbe river estuary. Over a period of two years the change of the geometrical structure of two different groyne shapes is monitored automatically by utilising two terrestrial laser scanners mounted in protective housings, located each on a 12 m high platform. The self-contained monitoring systems perform scanning of the two groynes one to two times a day at low tide, as the structures are fully submerged at high tide. The long-periodical wave loads are also determined using pressure sensors in each groyne. To correlate the captured data with vessel events and analyse the effects, vessel related parameters are recorded utilizing the Automatic Identification System (AIS). This paper describes the automated processes for the data acquisition and focusses on the deformation that is calculated using current, extended and new algorithms of the Point Cloud Library. It shows the process chain from the acquisition of raw scan files from an elevated station to the filtering of point cloud, the registration, the calculation of pointwise changes and the aggregation to a grid for later correlation with ship parameters. When working outdoor in all kinds of weather conditions, the processes and equipment need to be robust and account for various cases and situations. This is especially applicable for the algorithms, which need to be adaptable to different scenarios like wet surfaces or snow and unwelcome objects ranging from flotsam to birds sitting on the groyne. At the current stage of the research, deformation in the magnitude of a couple of decimetres is observable. The orientation and location of the deformation is on the seaward side and corresponds to the lower distance of vessels leaving the harbour

The interaction of CO and Li at a Ru(001) surface - a thermal desorption study

The interaction of carbon monoxide with the alkali metal lithium is studied on the single crystal substrate ruthenium surface Ru(0 0 1). The exceptionally strong interaction between CO and Li is investigated under various CO and Li coverages. Temperature programmed desorption spectroscopy shows the shift of the low coverage CO desorption peak (theta (CO) < 0.05) from its initial desorption temperature at 520-840 K when the lithium coverage is increased from zero to 1/3 of a mono-layer. Above that, the CO desorption temperature does no longer shift, but the desorption is concentrated in a single sharp Li/CO codesorption feature. Even stronger interaction of CO and Li is seen on a gold covered Ru surface (Au/Ru(0 0 1)). Au blocks the adsorption of CO. In the presence of Li however CO adsorbs readily. The uptake is roughly half that of the bare Ru surface and the thermal desorption occurs only above 900 K with the strong codesorption feature of Li and CO at 1080 K. The formation of a Au/Li alloy on the Ru substrate is confirmed. (C) 2001 Elsevier Science B.V. All rights reserved