Fatal Course of Cutaneous Cholesterol Embolization Syndrome: A Case Report.

Cholesterol embolization syndrome is an increasing but underestimated problem after endovascular intervention or after the start of thrombolytic therapies. Embolies from the aortic wall involves abdominal organs and the skin of the lower extremities or buttocks. In our case a progressive ulceration and necroses occurs spontaneously. Endovascular treatment of the lower extremities was successful for a short period. Due to the progression of necrosis, both legs were amputated. Biopsies were taken from the skin were initially no directions to the diagnosis of Cholesterol embolization syndrome. After a second elliptical excision biopsy the diagnosis of cholesterol embolization syndrome was confirmed. Because the rapid progression of skin necroses despite the treatment of prednisone, patient died due to sepsis and renal failure. This case shows when arterial revascularization is performed and progression in skin necrosis occurs despite optimal arterial vascular status the diagnosis CES should be considered and treated in an early state of disease.

3D alveolar in vitro model based on epithelialized biomimetically curved culture membranes.

There is increasing evidence that surface curvature at a near-cell-scale influences cell behaviour. Epithelial or endothelial cells lining small acinar or tubular body lumens, as those of the alveoli or blood vessels, experience such highly curved surfaces. In contrast, the most commonly used culture substrates for in vitro modelling of these human tissue barriers, ion track-etched membranes, offer only flat surfaces. Here, we propose a more realistic culture environment for alveolar cells based on biomimetically curved track-etched membranes, preserving the mainly spherical geometry of the cells' native microenvironment. The curved membranes were created by a combination of three-dimensional (3D) micro film (thermo)forming and ion track technology. We could successfully demonstrate the formation, the growth and a first characterization of confluent layers of lung epithelial cell lines and primary alveolar epithelial cells on membranes shaped into an array of hemispherical microwells. Besides their application in submerged culture, we could also demonstrate the compatibility of the bioinspired membranes for air-exposed culture. We observed a distinct cellular response to membrane curvature. Cells (or cell layers) on the curved membranes reveal significant differences compared to cells on flat membranes concerning membrane epithelialization, areal cell density of the formed epithelial layers, their cross-sectional morphology, and proliferation and apoptosis rates, and the same tight barrier function as on the flat membranes. The presented 3D membrane technology might pave the way for more predictive barrier in vitro models in future.

Quantification of [18F]afatinib using PET/CT in NSCLC patients: a feasibility study.

INTRODUCTION: Only a subgroup of non-small cell lung cancer (NSCLC) patients benefit from treatment using epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) such as afatinib. Tumour uptake of [18F]afatinib using positron emission tomography (PET) may identify those patients that respond to afatinib therapy. Therefore, the aim of this study was to find the optimal tracer kinetic model for quantification of [18F]afatinib uptake in NSCLC tumours. METHODS: [18F]Afatinib PET scans were performed in 10 NSCLC patients. The first patient was scanned for the purpose of dosimetry. Subsequent patients underwent a 20-min dynamic [15O]H2O PET scan (370 MBq) followed by a dynamic [18F]afatinib PET scan (342 ± 24 MBq) of 60 or 90 min. Using the Akaike information criterion (AIC), three pharmacokinetic plasma input models were evaluated with both metabolite-corrected sampler-based input and image-derived (IDIF) input functions in combination with discrete blood samples. Correlation analysis of arterial on-line sampling versus IDIF was performed. In addition, perfusion dependency and simplified measures were assessed. RESULTS: Ten patients were included. The injected activity of [18F]afatinib was 341 ± 37 MBq. Fifteen tumours could be identified in the field of view of the scanner. Based on AIC, tumour kinetics were best described using an irreversible two-tissue compartment model and a metabolite-corrected sampler-based input function (Akaike 50%). Correlation of plasma-based input functions with metabolite-corrected IDIF was very strong (r2 = 0.93). The preferred simplified uptake parameter was the tumour-to-blood ratio over the 60- to 90-min time interval (TBR60-90). Tumour uptake of [18F]afatinib was independent of perfusion. CONCLUSION: The preferred pharmacokinetic model for quantifying [18F]afatinib uptake in NSCLC tumours was the 2T3K_vb model. TBR60-90 showed excellent correlation with this model and is the best candidate simplified method. TRIAL REGISTRATION: https://eudract.ema.europa.eu/ nr 2012-002849-38.

Whole body PD-1 and PD-L1 positron emission tomography in patients with non-small-cell lung cancer.

PD-L1 immunohistochemistry correlates only moderately with patient survival and response to PD-(L)1 treatment. Heterogeneity of tumor PD-L1 expression might limit the predictive value of small biopsies. Here we show that tumor PD-L1 and PD-1 expression can be quantified non-invasively using PET-CT in patients with non-small-cell lung cancer. Whole body PD-(L)1 PET-CT reveals significant tumor tracer uptake heterogeneity both between patients, as well as within patients between different tumor lesions.

[Nurses to be preferred over physicians in elderly care?] / Liever verpleegkundige in ouderenzorg dan arts?

A thorough systematic literature review comparing care for the elderly provided by physicians and nurses with that provided by physicians alone finds a modest advantage for the first. The conclusion is that 'Physician substitution in healthcare for the aging population may achieve at least as good patient outcomes and process of care outcomes compared with care provided by physicians'. On closer inspection, the selected studies compare multidisciplinary care programmes including nursing staff with monodisciplinary physician care. The modest advantage found for the multidisciplinary programmes can be seen as support for the prevailing consensus that this is the way to go, but the conclusion that this is support for the substitution of physicians lacks evidence. Focus on cost-effectiveness and/or the wish to accentuate the important role of highly trained nursing experts in modern care for older people may have affected the interpretation of the data.

Delivery systems for the treatment of degenerated intervertebral discs.

The intervertebral disc (IVD) is the most avascular and acellular tissue in the body and therefore prone to degeneration. During IVD degeneration, the balance between anabolic and catabolic processes in the disc is deregulated, amongst others leading to alteration of extracellular matrix production, abnormal enzyme activities and production of pro-inflammatory substances like cytokines. The established treatment strategy for IVD degeneration consists of physiotherapy, pain medication by drug therapy and if necessary surgery. This approach, however, has shown limited success. Alternative strategies to increase and prolong the effects of bioactive agents and to reverse the process of IVD degeneration include the use of delivery systems for drugs, proteins, cells and genes. In view of the specific anatomy and physiology of the IVD and depending on the strategy of the therapy, different delivery systems have been developed which are reviewed in this article.

Laboratory diagnosis of paraneoplastic pemphigus.

BACKGROUND: Paraneoplastic pemphigus (PNP) is a multiorgan disease characterized by antibodies against plakins, desmogleins and the α2-macroglobulin-like-1 (A2ML1) protein, in association with an underlying neoplasm. Accurate diagnosis relies on the demonstration of these autoantibodies in serum. OBJECTIVES: To evaluate the value of different laboratory techniques in the serological diagnosis of PNP. METHODS: We performed immunoblotting, envoplakin (EP) enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence (IIF) on rat bladder, radioactive immunoprecipitation and a nonradioactive combined immunoprecipitation-immunoblot assay. Additional assays included BP180 ELISA and BP230 ELISA. We included the sera of 19 patients with PNP and 40 control subjects. RESULTS: The sensitivities were 63% for anti-EP ELISA, 74% for rat bladder IIF, 89% for immunoblotting, 95% for radioactive immunoprecipitation and 100% for nonradioactive immunoprecipitation. Specificities ranged from 86% to 100%. The BP180 and BP230 ELISAs had low sensitivity and specificity for PNP. The combination of rat bladder IIF and immunoblot showed 100% sensitivity and specificity. The analysis of sequential PNP sera showed that antibody titres may decrease over time, possibly resulting in negative outcomes for EP ELISA and rat bladder IIF studies. CONCLUSIONS: The detection of autoantibodies against EP and periplakin, or A2ML1 by immunoprecipitation is most sensitive for PNP. The combination of rat bladder IIF and immunoblotting is equally sensitive and highly specific, and represents an alternative valuable and relatively easy approach for the serological diagnosis of PNP.

Corrugated round fibers to improve cell adhesion and proliferation in tissue engineering scaffolds.

Optimal cell interaction with biomaterial scaffolds is one of the important requirements for the development of successful in vitro tissue-engineered tissues. Fast, efficient and spatially uniform cell adhesion can improve the clinical potential of engineered tissue. Three-dimensional (3-D) solid free form fabrication is one widely used scaffold fabrication technique today. By means of deposition of polymer fibers, scaffolds with various porosity, 3-D architecture and mechanical properties can be prepared. These scaffolds consist mostly of solid round fibers. In this study, it was hypothesized that a corrugated fiber morphology enhances cell adhesion and proliferation and therefore leads to the development of successful in vitro tissue-engineered constructs. Corrugated round fibers were prepared and characterized by extruding poly(ethylene oxide terephthalate)-co-poly(butylene terephthalate) (300PEOT55PBT45) block co-polymer through specially designed silicon wafer inserts. Corrugated round fibers with 6 and 10 grooves on the fiber surface were compared with solid round fibers of various diameters. The culture of mouse pre-myoblast (C2C12) cells on all fibers was studied under static and dynamic conditions by means of scanning electron microscopy, cell staining and DNA quantification. After 7days of culturing under static conditions, the DNA content on the corrugated round fibers was approximately twice as high as that on the solid round fibers. Moreover, under dynamic culture conditions, the cells on the corrugated round fibers seemed to experience lower mechanical forces and therefore adhered better than on the solid round fibers. The results of this study show that the surface architecture of fibers in a tissue engineering scaffold can be used as a tool to improve the performance of the scaffold in terms of cell adhesion and proliferation.

Tissue engineering of small-diameter vascular grafts: a literature review.

For the treatment of cardiovascular disease, functional arterial blood vessel prostheses with an inner diameter less than 6 mm are needed. This article gives an overview of the preparation of such vascular grafts by means of tissue engineering.

Shear stress induces a transient and VEGFR-2-dependent decrease in the motion of injected particles in endothelial cells.

Vascular endothelial cells form the inner lining of all blood vessels and play a central role in vessel physiology and disease. Endothelial cells are highly responsive to the mechanical stimulus of fluid shear stress that is exerted by blood flowing over their surface. In this study, the immediate micromechanical response of endothelial cells to physiological shear stress was characterized by tracking of ballistically injected, sub-micron, fluorescent particles. It was found that the mean squared displacement (MSD) of the particles decreases by a factor 1.5 within 10 min after the onset of shear stress. This decrease in particle motion is transient, since the MSD returns to control values within 15-30 min after the onset of shear. The immediate micromechanical stiffening is dependent on activation of the vascular endothelial growth factor receptor (VEGFR)-2, because inhibition of the receptor abrogates the micromechanical response. This work shows that the cytoskeleton is actively involved in the acute, functional response of endothelial cells to shear stress.

The nucleation kinetics of ZnO nanoparticles from ZnCl2 in ethanol solutions.

The first stages of the synthesis of ZnO nanoparticles by forced hydrolysis of ZnCl2 with NaOH and water in ethanol have been investigated using UV-Vis spectrophotometry. At sufficiently low water concentrations, focusing of the nanoparticle size distribution was observed during the nucleation and growth phase, followed by a defocusing phase when coarsening becomes significant. During nucleation and growth, only the smaller particles grow while the larger particles have an essentially zero growth rate, indicating that the growth rate decreases rapidly with particle size. As the average particle size remains nearly constant in this regime, the absorbance increase with time can be used to determine the nucleation rate. The nucleation rate was found to depend on both the water concentration and the reactant concentrations. The results are discussed in terms of a mechanism where water determines the precursor formation kinetics thus controlling the nucleation rate.

Analyzing shear stress-induced alignment of actin filaments in endothelial cells with a microfluidic assay.

The physiology of vascular endothelial cells is strongly affected by fluid shear stress on their surface. In this study, a microfluidic assay was employed to analyze the alignment of actin filaments in endothelial cells in response to shear stress. When cells were cultured in microfluidic channels and subjected to shear stress, the alignment of filaments in the channel direction was significantly higher than in static cultures. By adding inhibitory drugs, the roles of several signaling proteins in the process of alignment were determined. Thus, it is shown how microfluidic technology can be employed to provide a mechanistic insight into cell physiology.

Effective seeding of smooth muscle cells into tubular poly(trimethylene carbonate) scaffolds for vascular tissue engineering.

Porous tubular poly(trimethylene carbonate) (PTMC) scaffolds for vascular tissue engineering, with an inner diameter of 3 mm and a wall thickness of 1 mm, were prepared by means of dip-coating and subsequent leaching of NaCl particles. The scaffolds, with an average pore size of 110 µm and a porosity of 85%, showed a smooth muscle cell (SMC) seeding efficiency of only 10%. To increase the efficiency of cell seeding, these scaffolds were coated with a microporous PTMC outer layer with a thickness of 0.1-0.4 mm, an average pore size of 28 µm, and a porosity of 65%. Coating of the scaffolds with the microporous outer layer did not influence the inner pore structure or the mechanical properties of the scaffolds to a significant extent. The intrinsic permeability of the scaffolds decreased from 60 × 10(-10) m(2) to approximately 5 × 10(-10) m(2) after coating with the microporous outer layer. The latter value is still relatively high indicating that these scaffolds may facilitate sufficient diffusion of nutrients and waste products during cell culturing. The efficiency of SMC seeding determined after 24 h cell adhesion in the scaffolds increased from less than 10% to 43% after coating with the microporous outer layer. The cells were homogeneously distributed in the scaffolds and cell numbers increased 60% during culturing for 7 days under stationary conditions. It is concluded that coating of porous tubular PTMC scaffolds with a microporous PTMC outer layer facilitates effective cell seeding in these scaffolds.

Flow cytometric analysis of the uptake of low-density lipoprotein by endothelial cells in microfluidic channels.

Acceptance of microfluidic technology in everyday laboratory practice by biologists is still low. One of the reasons for this is that the technology combines poorly with standard cell biological and biochemical analysis tools. Flow cytometry is an example of a conventional analytical tool that is considered to be incompatible with microfluidic technology and its inherent small sample sizes. In this study, it is shown that properly designed microfluidic devices contain cell populations that are large enough to be analyzed by flow cytometry. To illustrate this, the uptake of fluorescent human low-density lipoprotein (LDL) by human endothelial cells that were cultured in a microfluidic channel was analyzed. It was found that the uptake of LDL by the cells increased linearly over time. Moreover, the uptake decreased when cells were pretreated with fluid shear stress inside the microfluidic devices. This study shows that microfluidic technology can be combined with conventional flow cytometry, while retaining the advantages of working with microfluidics such as low reagent use and dynamic cell culture conditions. This approach of combining microfluidic technology with conventional laboratory tools may contribute to greater acceptance of microfluidic devices in biological research.

Flexible and elastic porous poly(trimethylene carbonate) structures for use in vascular tissue engineering.

Biocompatible and elastic porous tubular structures based on poly(1,3-trimethylene carbonate), PTMC, were developed as scaffolds for tissue engineering of small-diameter blood vessels. High-molecular-weight PTMC (M(n) = 4.37 x 10(5)) was cross-linked by gamma-irradiation in an inert nitrogen atmosphere. The resulting networks (50-70% gel content) were elastic and creep resistant. The PTMC materials were highly biocompatible as determined by cell adhesion and proliferation studies using various relevant cell types (human umbilical vein endothelial cells (HUVECs), smooth muscle cells (SMCs) and mesenchymal stem cells (MSCs)). Dimensionally stable tubular scaffolds with an interconnected pore network were prepared by particulate leaching. Different cross-linked porous PTMC specimens with average pore sizes ranging between 55 and 116 microm, and porosities ranging from 59% to 83% were prepared. These scaffolds were highly compliant and flexible, with high elongations at break. Furthermore, their resistance to creep was excellent and under cyclic loading conditions (20 deformation cycles to 30% elongation) no permanent deformation occurred. Seeding of SMCs into the wall of the tubular structures was done by carefully perfusing cell suspensions with syringes from the lumen through the wall. The cells were then cultured for 7 days. Upon proliferation of the SMCs, the formed blood vessel constructs had excellent mechanical properties. Their radial tensile strengths had increased from 0.23 to 0.78 MPa, which is close to those of natural blood vessels.

Microfluidic technology in vascular research.

Vascular cell biology is an area of research with great biomedical relevance. Vascular dysfunction is involved in major diseases such as atherosclerosis, diabetes, and cancer. However, when studying vascular cell biology in the laboratory, it is difficult to mimic the dynamic, three-dimensional microenvironment that is found in vivo. Microfluidic technology offers unique possibilities to overcome this difficulty. In this review, an overview of the recent applications of microfluidic technology in the field of vascular biological research will be given. Examples of how microfluidics can be used to generate shear stresses, growth factor gradients, cocultures, and migration assays will be provided. The use of microfluidic devices in studying three-dimensional models of vascular tissue will be discussed. It is concluded that microfluidic technology offers great possibilities to systematically study vascular cell biology with setups that more closely mimic the in vivo situation than those that are generated with conventional methods.

How do long-term development and periodical changes of river-floodplain systems affect the fate of contaminants? Results from European rivers.

In many densely populated areas, riverine floodplains have been strongly impacted and degraded by river channelization and flood protection dikes. Floodplains act as buffers for flood water and as filters for nutrients and pollutants carried with river water and sediment from upstream source areas. Based on results of the EU-funded "AquaTerra" project (2004-2009), we analyze changes in the dynamics of European river-floodplain systems over different temporal scales and assess their effects on contaminant behaviour and ecosystem functioning. We find that human-induced changes in the hydrologic regime of rivers have direct and severe consequences on nutrient cycling and contaminant retention in adjacent floodplains. We point out the complex interactions of contaminants with nutrient availability and other physico-chemical characteristics (pH, organic matter) in determining ecotoxicity and habitat quality, and draw conclusions for improved floodplain management.