Comparison of three commercially available buffy coat pooling sets for the preparation of platelet concentrates

Background: A disposable set for platelet concentrate (PC) preparation by the buffy coat method allows pooling of buffy coats, centrifugation and cell separation with in-line leucocyte filtration. This study compares three commercially available pooling sets in combination with INTERCEPT pathogen inactivation (PI). Materials and methods: Sets for pooling of buffy coats were from Fresenius Kabi (FRE), Macopharma (MAC) and Terumo BCT (TER). Platelet yield, recovery and concentration were compared before and after PI (n = 20). Platelet quality was assessed by annexin V binding, P-selectin expression and PAC1 binding. Results: The TER pooling set had the highest platelet yield (539 044 x 10(11)) compared with MAC (453 +/- 077) and FRE (456 +/- 051) prior to PI. This was the result of a significantly higher platelet concentration in the TER storage bag (141 +/- 012 x 10(6)/L) compared with MAC (118 +/- 019) and FRE (128 +/- 015). However, the TER platelet content decreased by 156% after PI, yielding 455 +/- 047 x 10(11) platelets compared with smaller reductions at 95% for MAC (410 +/- 069) and 44% for FRE (436 +/- 052). None of the individual PC contained >10(6) leucocytes. The pH in TER PC was lower compared with MAC and FRE caused by a higher lactic acid production rate. Consequently, PAC1 binding after TRAP activation was lowest for TER PC on day 6. P-selectin and annexin V were not different between suppliers. Conclusion: This study demonstrates the added value of evaluating the entire component production process when introducing a new consumable. This study helped to inform a decision on what pooling set is ideally suited for routine implementation taking into account PI

Auf den Spuren großer Naturforscher

Paris, die Hauptstadt der Französischen Republik, Sitz des Staatspräsidenten, der Regierung und der beiden Kammern des französischen Parlaments mit über zwei Millionen Einwohnern hat nicht nur für Kunstinteressierte kulturhistorisch einiges zu bieten, sonderrn eignet sich auch für eine Exkursion mit biologischem bzw. naturhistorischem Hintergrund. Von den zahlreichen Entdeckungsmöglichkeiten seien nachfolgend zwei Beispiele herausgegriffen, die einen „Kurztripp“ an die Seine bei jeder Witterung zu einem Naturerlebnis machen können

Polarization Modulation Using Wave Plates to Enhance Foveal Fixation Detection in Retinal Birefringence Scanning for Pediatric Vision Screening Purposes

To enhance foveal fixation detection while bypassing the deleterious effects of corneal birefringence in binocular retinal birefringence scanning (RBS) for pediatric vision screening purposes, a new RBS design was developed incorporating a double-pass spinning half wave plate (HWP) combined with a fixed double-pass retarder into the optical system. The spinning HWP enables essential differential polarization detection with only one detector, easing constraints on optical alignment and electronic balancing, and together with a fixed wave plate, this differential RBS signal can be detected essentially independent of various corneal retardances and azimuths. Utilizing the measured corneal birefringence from a dataset of 300 human eyes, an algorithm was developed in MATLAB for optimizing the properties of both wave plates to statistically maximize the RBS signal, while having the greatest independence from left and right eye corneal birefringence. Foveal fixation detection was optimized with the HWP spun 9/16 as fast as the circular scan, with the fixed retarder having a retardance of 45 degrees and fast axis at 90 degrees. Combined with bull's-eye focus detection, this computeroptimized RBS design promises to provide an effective screening instrument for automatic identification of infants at risk for amblyopia, the leading cause of vision loss in childhood

IgCAMs redundantly control axon navigation in Caenorhabditis elegans

<p>Abstract</p> <p>Background</p> <p>Cell adhesion molecules of the immunoglobulin superfamily (IgCAMs) form one of the largest and most diverse families of adhesion molecules and receptors in the nervous system. Many members of this family mediate contact and communication among neurons during development. The <it>Caenorhabditis elegans </it>genome contains a comparatively small number of IgCAMs, most of which are evolutionarily conserved and found across all animal phyla. Only some of these have been functionally characterized so far.</p> <p>Results</p> <p>We systematically analyzed previously uncharacterized IgCAMs in <it>C. elegans</it>. Green fluorescent protein reporter constructs of 12 IgCAMs revealed that expression generally is not confined to a single tissue and that all tissues express at least one of the IgCAMs. Most IgCAMs were expressed in neurons. Within the nervous system significant overlap in expression was found in central components of the motor circuit, in particular the command interneurons, ventral cord motoneurons as well as motoneurons innervating head muscles. Sensory neurons are underrepresented among the cells expressing these IgCAMs. We isolated mutations for eight of the genes showing neuronal expression. Phenotypic analysis of single mutants revealed limited neuronal defects, in particular axon navigation defects in some of the mutants. Systematic genetic interaction studies uncovered two cases of functional overlap among three and four genes, respectively. A strain combining mutations in all eight genes is viable and shows no additional defects in the neurons that were analyzed, suggesting that genetic interactions among those genes are limited.</p> <p>Conclusion</p> <p>Genetic interactions involving multiple IgCAMs affecting axon outgrowth demonstrate functional overlap among IgCAMs during nervous system development.</p

Lauschangriff auf Rabenvögel

Krähen gelten als unheimlich schlau und äußerst intelligent und haben sich deshalb als Modelle der Kognitionsforschung längst etabliert. Die erstaunlichen Gedächtnisleistungen sind sprichwörtlich. Lange hatten viele Forscher geglaubt, dass nur Menschen ein episodisches Gedächtnis besitzen, sich also an einzelne Erlebnisse erinnern können, etwa ein schönes Abendessen mit Freunden oder aber eine Situation, die sie als bedrohlich empfunden haben. Dass Kolkraben (Corvus corax) auf Alarmrufe von anderen Rabenvögeln reagieren, selbst wenn diese unbekannt sind, belegt, dass sie sich auch sehr gut interspezifisch – also über Artgrenzen hinweg – über solche „Erlebnisse“ verständigen können

Matrix approach of Full-Field OCT for volumetric imaging of an opaque human cornea

Optical microscopy offers the possibility to image biological tissue with a diffraction limited resolution (~µm). However, the heterogeneity of biological tissues can strongly affect light propagation at large depths by distorting the initial wavefront. Large and short range fluctuations of the refractive index can induce aberration and multiple scattering, respectively. Inspired by a recent work [1], we have developed a matrix approach to Full-Field Optical Coherence Tomography (FF-OCT) to push back the fundamental limit of aberrations and multiple scattering. Here, we report on the application of this approach to the imaging of the human cornea and the quantitative measurement of the corneal transparency. Please click Additional Files below to see the full abstract

Eye Movements, Strabismus, Amblyopia, and Neuro-Ophthalmology Vertical Vergence Adaptation Produces an Objective Vertical Deviation That Changes With Head Tilt

PURPOSE. To document the cyclovertical ocular motor mechanism used for vertical fusion in healthy subjects, and to explore whether vertical vergence training in healthy individuals can produce objectively confirmed vertical deviations that change with head tilt, revealing a basic mechanism that can produce a pattern of misalignment in an otherwise normal ocular motor system that is similar to superior oblique muscle paresis (SOP). METHODS. Seven subjects with normal orthoptic examinations were adapted to vertical image disparities using our tilting haploscopic eye-tracking apparatus presenting concentric circle targets without torsional cues. Static eye positions were recorded with head straight and when tilted 45 degrees to the left and right, during both binocular and monocular viewing. RESULTS. Vertical fusional vergence was accompanied by a cycloversion, with the downwardmoving eye intorting and the upward-moving eye extorting, implicating primary involvement of the oblique extraocular muscles. After adaptation to the slowly increasing vertical target separation, all subjects developed a temporary vertical deviation in the straight ahead position that increased with head tilt to one side and decreased with head tilt to the other side. CONCLUSIONS. These results not only show that head-tilt-dependent changes in vertical deviation are not necessarily pathognomonic for SOP, but also, and more importantly, suggest mechanisms that can mimic SOP and suggest a possible role for vertical vergence training in reducing deviations and thus the amount of head tilt required for fusion. Ultimately, vertical vergence training may provide an adjunct or alternative to extraocular muscle surgery in selected cases

In vivo imaging through the entire thickness of human cornea by full-field optical coherence tomography

Despite obvious improvements in visualization of the in vivo cornea through the faster imaging speeds and higher axial resolutions, cellular imaging stays unresolvable task for OCT, as en face viewing with a high lateral resolution is required. The latter is possible with FFOCT, a method that relies on a camera, moderate numerical aperture (NA) objectives and an incoherent light source to provide en face images with a micrometer-level resolution. Recently, we for the first time demonstrated the ability of FFOCT to capture images from the in vivo human cornea1. In the current paper we present an extensive study of appearance of healthy in vivo human corneas under FFOCT examination. En face corneal images with a micrometer-level resolution were obtained from the three healthy subjects. For each subject it was possible to acquire images through the entire corneal depth and visualize the epithelium structures, Bowman's layer, sub-basal nerve plexus (SNP) fibers, anterior, middle and posterior stroma, endothelial cells with nuclei. Dimensions and densities of the structures visible with FFOCT, are in agreement with those seen by other cornea imaging methods. Cellular-level details in the images obtained together with the relatively large field-of-view (FOV) and contactless way of imaging make this device a promising candidate for becoming a new tool in ophthalmological diagnostics

Modeling and minimizing interference from corneal birefringence in retinal birefringence scanning for foveal fixation detection

Utilizing the measured corneal birefringence from a data set of 150 eyes of 75 human subjects, an algorithm and related computer program, based on Müller-Stokes matrix calculus, were developed in MATLAB for assessing the influence of corneal birefringence on retinal birefringence scanning (RBS) and for converging upon an optical/mechanical design using wave plates (“wave-plate-enhanced RBS”) that allows foveal fixation detection essentially independently of corneal birefringence. The RBS computer model, and in particular the optimization algorithm, were verified with experimental human data using an available monocular RBS-based eye fixation monitor. Fixation detection using wave-plate-enhanced RBS is adaptable to less cooperative subjects, including young children at risk for developing amblyopia