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Akbani R.,University of Texas M. D. Anderson Cancer Center | Becker K.-F.,TU Munich | Carragher N.,University of Edinburgh | Goldstein T.,University of California at Santa Cruz | And 10 more authors.
Molecular and Cellular Proteomics | Year: 2014

Reverse phase protein array (RPPA) technology introduced a miniaturized "antigen-down" or "dot-blot" immunoassay suitable for quantifying the relative, semi-quantitative or quantitative (if a well-accepted reference standard exists) abundance of total protein levels and post-translational modifications across a variety of biological samples including cultured cells, tissues, and body fluids. The recent evolution of RPPA combined with more sophisticated sample handling, optical detection, quality control, and better quality affinity reagents provides exquisite sensitivity and high sample throughput at a reasonable cost per sample. This facilitates large-scale multiplex analysis of multiple post-translational markers across samples from in vitro, preclinical, or clinical samples. The technical power of RPPA is stimulating the application and widespread adoption of RPPA methods within academic, clinical, and industrial research laboratories. Advances in RPPA technology now offer scientists the opportunity to quantify protein analytes with high precision, sensitivity, throughput, and robustness. As a result, adopters of RPPA technology have recognized critical success factors for useful and maximum exploitation of RPPA technologies, including the following: • preservation and optimization of pre-analytical sample quality, • application of validated high-affinity and specific antibody (or other protein affinity) detection reagents, • dedicated informatics solutions to ensure accurate and robust quantification of protein analytes, and • quality-assured procedures and data analysis workflows compatible with application within regulated clinical environments. In 2011, 2012, and 2013, the first three Global RPPA workshops were held in the United States, Europe, and Japan, respectively. These workshops provided an opportunity for RPPA laboratories, vendors, and users to share and discuss results, the latest technology platforms, best practices, and future challenges and opportunities. The outcomes of the workshops included a number of key opportunities to advance the RPPA field and provide added benefit to existing and future participants in the RPPA research community. The purpose of this report is to share and disseminate, as a community, current knowledge and future directions of the RPPA technology. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc. Source

Elmlinger M.W.,Nycomed International Management GmbH | Kriebel M.,Natural and Medical science Institute | Ziegler D.,Heinrich Heine University Dusseldorf | Ziegler D.,University Hospital
NeuroMolecular Medicine | Year: 2011

The recently described therapeutic benefits of the hemodialysate actovegin on neuropathic symptoms in diabetic patients with symptomatic polyneuropathy suggest a neuroprotective activity of the drug. To elucidate the possible cellular mechanism of the pharmacological effects of actovegin, we investigated its effects on cultured primary rat neurons in vitro. Primary neurons were cultured for up to 10 days in the presence of increasing doses of actovegin (0.3-1,000 mg/l). Total cell number, dendrite length and the number of excitatory synapses, i.e., the amount of the synaptic V-Glut1 protein, were measured by immunocytochemistry followed by fluorescence microscopy. The apoptotic level in neurons after induction of apoptosis by amyloid peptide Aβ 25-35 was assessed by the level of activated caspase-3. In addition, the capability of the neurons to diminish oxidative stress was assessed by measuring the cellular level of reactive oxygen species ROS in the presence of actovegin. Actovegin treatment yielded an increased maintenance of neuronal cells and total number of synapses and could lower the level of activated caspase-3 in a dose-dependent manner. Dendrite lengths were not significantly affected. In addition, actovegin reduced the cellular level of ROS in cultured neurons. The cellular effects observed suggest neuroprotective and anti-oxidative effects of the drug Actovegin®, which could at least partially explain its therapeutic benefits. © The Author(s) 2011. Source

Zeitler R.,Max Planck Institute of Biochemistry | Fromherz P.,Max Planck Institute of Biochemistry | Zeck G.,Natural and Medical science Institute
Applied Physics Letters | Year: 2011

Neuroprosthetic devices rely on a tight contact between electrodes and neurons in the interfaced tissue. A simple method to probe the contact properties in a non-invasive way would be highly attractive. Here we show for retinal tissue that crucial electrical properties of the interface can be extracted from the voltage noise that is recorded with an array of capacitive sensors. The monitoring of the interface properties, which are either interpreted as variable local conductivities or as a cleft of varying distance, allows assessment of the long-term efficiency of neuroprosthetic devices. © 2011 American Institute of Physics. Source

Dieckmann A.,Nycomed GmbH | Kriebel M.,Natural and Medical science Institute | Andriambeloson E.,Neurofit SAS | Ziegler D.,Heinrich Heine University Dusseldorf | Elmlinger M.,Nycomed International Management GmbH
Experimental and Clinical Endocrinology and Diabetes | Year: 2012

Background: Diabetic neuropathy is one of the most severe complications of diabetes, affecting approximately one-third of diabetic patients. We investigated the potential neuroprotective effect of Actovegin®, a deproteinized hemoderivative of calf blood, in an animal model of diabetic neuropathy. Methods: A single intravenous injection of streptozotocin (STZ, 55 mg/kg) was used to induce experimental diabetes in male Sprague-Dawley rats. Actovegin® (200 or 600 mg/kg) was administered intraperitoneally from day 11 to day 40 post-STZ exposure. N-acetylcysteine (NAC) was used as a positive control and was added to drinking water (0.2 g/l) from day 2 until day 40. Measurements to assess efficacy included sensory nerve conduction velocity (SNCV), intraepidermal nerve fiber density (IENFD), and poly(ADP-ribose) content. Results: A decrease (35%) in sensory nerve conduction velocity (SNCV) was seen in STZ-induced diabetic rats from day 10 post-STZ administration and persisted at days 25 and 39. At study completion (day 41), a decrease (32%) in intraepidermal nerve fiber density (IENFD) was found in hind-paw skin biopsies from STZ-rats. Reduced SNCV and IENFD were significantly ameliorated by both doses of Actovegin®. Moreover, 600 mg/kg Actovegin® markedly decreased poly(ADP-ribose) polymerase (PARP) activity in sciatic nerves from STZ-diabetic rats as assessed by poly(ADP-ribose) content. Conclusion: Actovegin® improved several parameters of experimental diabetic neuropathy via mechanisms involving suppression of PARP activation, providing a rationale for treatment of this disease in humans. © 2012 Georg Thieme Verlag KG Stuttgart New York. Source

Fuchsberger K.,Natural and Medical science Institute | Goff A.L.,University of Trieste | Gambazzi L.,Ecole Polytechnique Federale de Lausanne | Toma F.M.,University of Trieste | And 4 more authors.
Small | Year: 2011

A facile method is proposed for the deposition of multiwalled carbon nanotube (MWCNT) layers onto microelectrode arrays by means of a microcontact printing technique, leading to the fabrication of MEAs characterized by well defined electrical and morphological properties. Using polydimethyl siloxane stamps, produced from different mold designs, a flexibility of printing is achieved that provides access to microscale, nanostructured electrodes. The thickness of MWCNT layers can be exactly predetermined by evaluating the concentration of the MWCNT solution employed in the process. The electrode morphology is further characterized using laser scanning and scanning electron microscopy. Next, by means of impedance spectroscopy analysis, the MWCNT-electrode contact resistance and MWCNT film resistance is measured, while electrochemical impedance spectroscopy is used to estimate the obtained electrode-electrolyte interface. Structural and electrochemical properties make these electrodes suitable for electrical stimulation and recording of neurons and electrochemical detection of dopamine. MWCNT-functionalized electrodes show the ability to detect micromolar amounts of dopamine with a sensitivity of 19 nA μm-1. In combination with their biosensing properties, preliminary electrophysiological measurements show that MWCNT microelectrodes have recording properties superior to those of commercial TiN microelectrodes when detecting neuronal electrical activity under long-term cell-culture conditions. MWCNT-functionalized microelectrode arrays fabricated by microcontact printing represent a versatile and multipurpose platform for cell-culture monitoring. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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