Cynomolgus monkey's choroid reference database derived from hybrid deep learning optical coherence tomography segmentation.

Cynomolgus monkeys exhibit human-like features, such as a fovea, so they are often used in non-clinical research. Nevertheless, little is known about the natural variation of the choroidal thickness in relation to origin and sex. A combination of deep learning and a deterministic computer vision algorithm was applied for automatic segmentation of foveolar optical coherence tomography images in cynomolgus monkeys. The main evaluation parameters were choroidal thickness and surface area directed from the deepest point on OCT images within the fovea, marked as the nulla with regard to sex and origin. Reference choroid landmarks were set underneath the nulla and at 500 µm intervals laterally up to a distance of 2000 µm nasally and temporally, complemented by a sub-analysis of the central bouquet of cones. 203 animals contributed 374 eyes for a reference choroid database. The overall average central choroidal thickness was 193 µm with a coefficient of variation of 7.8%, and the overall mean surface area of the central bouquet temporally was 19,335 µm2 and nasally was 19,283 µm2. The choroidal thickness of the fovea appears relatively homogeneous between the sexes and the studied origins. However, considerable natural variation has been observed, which needs to be appreciated

Intravital Two-Photon Microscopy of Immune Cell Dynamics in Corneal Lymphatic Vessels

BACKGROUND: The role of lymphatic vessels in tissue and organ transplantation as well as in tumor growth and metastasis has drawn great attention in recent years. METHODOLOGY/PRINCIPAL FINDINGS: We now developed a novel method using non-invasive two-photon microscopy to simultaneously visualize and track specifically stained lymphatic vessels and autofluorescent adjacent tissues such as collagen fibrils, blood vessels and immune cells in the mouse model of corneal neovascularization in vivo. The mouse cornea serves as an ideal tissue for this technique due to its easy accessibility and its inducible and modifiable state of pathological hem- and lymphvascularization. Neovascularization was induced by suture placement in corneas of Balb/C mice. Two weeks after treatment, lymphatic vessels were stained intravital by intrastromal injection of a fluorescently labeled LYVE-1 antibody and the corneas were evaluated in vivo by two-photon microscopy (TPM). Intravital TPM was performed at 710 nm and 826 nm excitation wavelengths to detect immunofluorescence and tissue autofluorescence using a custom made animal holder. Corneas were then harvested, fixed and analyzed by histology. Time lapse imaging demonstrated the first in vivo evidence of immune cell migration into lymphatic vessels and luminal transport of individual cells. Cells immigrated within 1-5.5 min into the vessel lumen. Mean velocities of intrastromal corneal immune cells were around 9 µm/min and therefore comparable to those of T-cells and macrophages in other mucosal surfaces. CONCLUSIONS: To our knowledge we here demonstrate for the first time the intravital real-time transmigration of immune cells into lymphatic vessels. Overall this study demonstrates the valuable use of intravital autofluorescence two-photon microscopy in the model of suture-induced corneal vascularizations to study interactions of immune and subsequently tumor cells with lymphatic vessels under close as possible physiological conditions

Unraveling the deep learning gearbox in optical coherence tomography image segmentation towards explainable artificial intelligence

Machine learning has greatly facilitated the analysis of medical data, while the internal operations usually remain intransparent. To better comprehend these opaque procedures, a convolutional neural network for optical coherence tomography image segmentation was enhanced with a Traceable Relevance Explainability (T-REX) technique. The proposed application was based on three components: ground truth generation by multiple graders, calculation of Hamming distances among graders and the machine learning algorithm, as well as a smart data visualization ('neural recording'). An overall average variability of 1.75% between the human graders and the algorithm was found, slightly minor to 2.02% among human graders. The ambiguity in ground truth had noteworthy impact on machine learning results, which could be visualized. The convolutional neural network balanced between graders and allowed for modifiable predictions dependent on the compartment. Using the proposed T-REX setup, machine learning processes could be rendered more transparent and understandable, possibly leading to optimized applications

Stromal transcriptional profiles reveal hierarchies of anatomical site, serum response and disease and identify disease specific pathways

Synovial fibroblasts in persistent inflammatory arthritis have been suggested to have parallels with cancer growth and wound healing, both of which involve a stereotypical serum response programme. We tested the hypothesis that a serum response programme can be used to classify diseased tissues, and investigated the serum response programme in fibroblasts from multiple anatomical sites and two diseases. To test our hypothesis we utilized a bioinformatics approach to explore a publicly available microarray dataset including rheumatoid arthritis (RA), osteoarthritis (OA) and normal synovial tissue, then extended those findings in a new microarray dataset representing matched synovial, bone marrow and skin fibroblasts cultured from RA and OA patients undergoing arthroplasty. The classical fibroblast serum response programme discretely classified RA, OA and normal synovial tissues. Analysis of low and high serum treated fibroblast microarray data revealed a hierarchy of control, with anatomical site the most powerful classifier followed by response to serum and then disease. In contrast to skin and bone marrow fibroblasts, exposure of synovial fibroblasts to serum led to convergence of RA and OA expression profiles. Pathway analysis revealed three inter-linked gene networks characterising OA synovial fibroblasts: Cell remodelling through insulin-like growth factors, differentiation and angiogenesis through -3 integrin, and regulation of apoptosis through CD44. We have demonstrated that Fibroblast serum response signatures define disease at the tissue level, and that an OA specific, serum dependent repression of genes involved in cell adhesion, extracellular matrix remodelling and apoptosis is a critical discriminator between cultured OA and RA synovial fibroblasts

Tracking the evolutionary history of Cortinarius species in section Calochroi, with transoceanic disjunct distributions

<p>Abstract</p> <p>Background</p> <p><it>Cortinarius </it>species in section <it>Calochroi </it>display local, clinal and circumboreal patterns of distribution across the Northern Hemisphere where these ectomycorrhizal fungi occur with host trees throughout their geographical range within a continent, or have disjunct intercontinental distributions, the origins of which are not understood. We inferred evolutionary histories of four species, 1) <it>C</it>. <it>arcuatorum</it>, 2) <it>C. aureofulvus</it>, 3) <it>C</it>. <it>elegantior </it>and 4) <it>C. napus</it>, from populations distributed throughout the Old World, and portions of the New World (Central- and North America) based on genetic variation of 154 haplotype internal transcribed spacer (ITS) sequences from 83 population samples. By describing the population structure of these species across their geographical distribution, we attempt to identify their historical migration and patterns of diversification.</p> <p>Results</p> <p>Models of population structure from nested clade, demographic and coalescent-based analyses revealed genetically differentiated and geographically structured haplotypes in <it>C</it>. <it>arcuatorum </it>and <it>C</it>. <it>elegantior</it>, while <it>C</it>. <it>aureofulvus </it>showed considerably less population structure and <it>C. napus </it>lacked sufficient genetic differentiation to resolve any population structure. Disjunct populations within <it>C</it>. <it>arcuatorum, C. aureofulvus </it>and <it>C</it>. <it>elegantior </it>show little or no morphological differentiation, whereas in <it>C. napus </it>there is a high level of homoplasy and phenotypic plasticity for veil and lamellae colour. The ITS sequences of the type specimens of <it>C. albobrunnoides </it>and <it>C. albobrunnoides </it>var. <it>violaceovelatus </it>were identical to one another and are treated as one species with a wider range of geographic distribution under <it>C. napus</it>.</p> <p>Conclusions</p> <p>Our results indicate that each of the <it>Calochroi </it>species has undergone a relatively independent evolutionary history, hypothesised as follows: 1) a widely distributed ancestral population of <it>C</it>. <it>arcuatorum </it>diverged into distinctive sympatric populations in the New World; 2) two divergent lineages in <it>C</it>. <it>elegantior </it>gave rise to the New World and Old World haplotypes, respectively; and 3) the low levels of genetic divergence within <it>C</it>. <it>aureofulvus </it>and <it>C</it>. <it>napus </it>may be the result of more recent demographic population expansions. The scenario of migration via the Bering Land Bridge provides the most probable explanation for contemporaneous disjunct geographic distributions of these species, but it does not offer an explanation for the low degree of genetic divergence between populations of <it>C. aureofulvus </it>and <it>C. napus</it>. Our findings are mostly consistent with the designation of New World allopatric populations as separate species from the European counterpart species <it>C. arcuatorum </it>and <it>C. elegantior</it>. We propose the synonymy of <it>C. albobrunnoides</it>, <it>C. albobrunnoides </it>var. <it>violaceovelatus </it>and <it>C. subpurpureophyllus </it>var. <it>sulphureovelatus </it>with <it>C. napus</it>. The results also reinforce previous observations that linked <it>C. arcuatorum </it>and <it>C. aureofulvus </it>displaying distributions in parts of North America and Europe. Interpretations of the population structure of these fungi suggest that host tree history has heavily influenced their modern distributions; however, the complex issues related to co-migration of these fungi with their tree hosts remain unclear at this time.</p

25th annual computational neuroscience meeting: CNS-2016

The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

Charakterisierung von Geruchsstoffen in Klebstoffen

Adhesives are an indispensable material for joining different materials. Without adhesives, modern industry would not be able to produce such a large number of products. Adhesives are mostly synthetic, however natural ones, such as resins or casein, are also used. Since adhesives are often associated with unpleasant odors and little is known about the odor-causing compounds, this work deals with the elucidation of the odorants in adhesives. In the first study, various acrylate-based adhesives were screened for odor active substances by means of gas chromatography-olfactometry (GC-O) and their identification by gas chromatography-mass spectrometry/olfactometry (GC-MS/O). In this way, a variety of odorants could be elucidated, which have previously not been reported in the literature as odor-active substances in adhesives. Besides odorous monomers associated with the adhesives, additional trace components with potent smell properties could be identified as odor causing substances. In the second part of this work, four elastic therapeutic tapes, which were marked by a pronounced off-odor, were examined. These tapes contained an acrylic adhesive for the adhesion to the skin. Based on a series of GC analyses, more than 30 odor-active substances could be identified. Here, 2-ethyl-1-hexanol could be elucidated as one of the most potent odorants responsible for the off-odor. This substance is well-known as a degradation product of a monomer of acrylic adhesives. To put the relative smell contribution of these substances into relation to each other, 2-ethyl-1-hexanol and a series of other substances were quantified. In the third part of the work, waxes with different manufacturing processes were investigated, due to the fact that hot-melt adhesives contain a large amount of synthetic waxes and play an important economic role in the field of adhesive manufacturing. In this case, different analytical approaches were administered, namely a solvent extraction as well as a thermal desorption of the odorous fraction followed by GC-MS/O analysis. In this way, a release of the odorants during the melting of an adhesive could be simulated. In addition to the odorants identified by solvent extraction, it was also possible to identify more highly volatile substances. This thermal desorption showed to be a fast and effective method for the identification of odors emanating during a melting process. Acrylate-based products such as adhesives or paints have different compositions, potentially leading to a multitude of by-products, namely acrylate derivatives. As studies on real samples indicated a series of such by-products, different esters of acrylic acid were systematically iv synthesized and examined with regard to their odor properties, such as smell character and odor thresholds in the fourth part of this work. In addition, chromatographic and spectrometric data were compiled. Structural analogues containing acrylate moieties were found to exhibit olfactory similarities with known odorants lacking this specific structural feature. This allows elaborating structural features that are representative for specific smell impressions. Moreover, such data support future identification of unknown compounds.Klebstoffe stellen in der heutigen Zeit einen unabdingbaren Werkstoff für das Fügen unterschiedlicher Materialien dar. Ohne diese wäre die moderne Industrie nicht in der Lage eine Vielzahl ihrer Produkte zu erzeugen. Bei den verwendeten Klebstoffen handelt es sich zumeist um synthetisch hergestellt Produkte, wobei auch natürliche Rohstoffe, wie beispielsweise Harze oder Casein, zum Einsatz kommen. Da Klebstoffe häufig mit einem unangenehmen Geruch verbunden sind und wenig über die geruchsverursachenden Verbindungen bekannt ist, befasste sich diese Arbeit mit der Aufklärung der in Klebstoffen enthaltenen Geruchsstoffe. In einer ersten Studie wurden verschiedene Acrylat-basierte Klebstoffe einem Screening auf geruchsaktive Substanzen mittels Gaschromatographie-Olfaktometrie (GC-O) unterzogen, sowie deren Identifizierung durch Gaschromatographie-Massenspektrometrie/Olfaktometrie (GC-MS/O) durchgeführt. Auf diese Weise konnte eine Vielzahl von Geruchsstoffen aufgeklärt werden, welche in der Literatur noch nicht als geruchsaktive Substanzen in Klebstoffen bekannt waren. Neben geruchspotenten Monomeren der Klebstoffe konnten insbesondere Spurenkomponenten als geruchsverursachend aufgeklärt werden. Im zweiten Teil dieser Arbeit wurden vier durch einen Fehlgeruch auffällige, kinesiologische Tapes untersucht. Diese enthielten für die Haftung auf der Haut einen Acrylatklebstoff. Mittels verschiedenen gaschromatographisch-olfaktometrischen Analysen konnten über 30 geruchsaktive Substanzen identifiziert werden. Hierbei wurde 2-Ethyl-1-hexanol als einer der potentesten Geruchsstoffe, ursächlich für den Fehlgeruch, aufgeklärt. Diese Substanz war bereits als Abbauprodukt eines Monomers von Acrylatklebstoffen bekannt und wurde zur Objektivierung ihres Beitrags, neben anderen Geruchsstoffen, einer Quantifizierung unterzogen. Im dritten Teil der Arbeit wurden verschieden hergestellte Wachse untersucht, da Hotmelt-Klebstoffe einen großen Anteil an synthetischen Wachsen enthalten und somit als Basisrohstoffe im Bereich klebender Komponenten von hoher wirtschaftlicher Bedeutung sind. Hierbei wurde, neben einer Lösungsmittelextraktion, eine Thermodesorption mit anschließender GC-MS/O Analyse durchgeführt. Auf diese Weise konnte eine Freisetzung der Geruchsstoffe während des Schmelzens eines Klebstoffes simuliert werden. Hierbei konnten, neben den durch Lösungsmittelextraktion identifizierten Geruchsstoffen, auch leichter flüchtige Substanzen identifiziert werden. Es konnte somit gezeigt werden, dass die vi Thermodesorption eine schnelle und effektive Methode für die Identifizierung der Geruchsstoffe während eines Schmelzprozesses darstellt. Da Acrylat–basierte Produkte, wie Klebstoffe oder Farben, unterschiedliche Zusammensetzungen haben und damit viele Nebenprodukte auftreten können, wurden im vierten Teil der Arbeit unterschiedliche Ester der Acrylsäure synthetisiert und auf geruchsspezifische Eigenschaften, wie Geruchsqualitäten und Geruchsschwellenwerte, sowie chromatographische und spektrometrische Eigenschaften untersucht. Hierbei wurde gezeigt, dass Strukturanaloga bekannter Geruchsstoffe mit ähnlichen Geruchseigenschaften beschrieben werden konnten. Eine zukünftige Identifizierung unbekannter Verbindungen wird auf Basis derartiger sensorischer und analytischer Daten wesentlich erleichtert

Identification and quantification of glue-like off-odors in elastic therapeutic tapes

Elastic therapeutic tapes are an important tool in the field of physical therapy and medicine. These tapes contain types of adhesive. However, sensory evaluations revealed the release of pronounced and irritating odors of the tapes. Negative odors were, amongst others, reported in elastic therapeutic tapes containing acrylic adhesives. In this study, the odor of four different tape samples was evaluated applying a descriptive analysis approach carried out by a trained sensory panel. Afterwards, the volatile compounds were recovered from the samples by solvent extraction and isolated by solvent-assisted flavor evaporation (SAFE). The obtained distillates were subsequently analyzed by gas chromatography-olfactometry (GC-O) and two-dimensional GC-O coupled with mass spectrometry (2D-GC-MS/O). To determine the most potent odorants in the distillates, odor extract dilution analyses (OEDA) were carried out. Thirty-one odorants were successfully identified using this approach, which were all described for the first time as odorants in tapes. Amongst the set of volatiles, unsaturated and saturated aldehydes were present, eliciting fatty, soapy, and citrus-like odor impressions, as well as a range of glue-like, moldy, and fruity smelling odor-active volatiles, such as 2-ethyl-1-hexanol, butyl benzoate, and 3-phenyltoluene. Based on their relative intensities, the concentrations of the glue-like smelling substances were determined: 2-ethyl-1-hexanol, present in all samples, was determined with concentrations ranging from 10 to 200 mg/kg in the investigated tapes

Sensory characterization and identification of odorous constituents in acrylic adhesives

Most products in our surroundings contain adhesives, including acrylic adhesives which are used in many industry sectors. Some of these adhesives contain solvents that produce strong odors, but even adhesives which are produced without solvents can emit intensive or pungent odors. In the latter case, the odor may arise from monomers in the adhesive product, from manufacturing by-products or from degradation products. Here we analyzed several acrylic, methacrylic and benzyl acrylic adhesives to identify representative odorous contaminants. The volatile fraction of the products was extracted and isolated by solvent-assisted flavor evaporation (SAFE), then analyzed via high-resolution gas chromatography olfactometry (HRGC-O), HRGC-mass spectrometry (HRGC-MS/O) and two-dimensional HRGC-MS/O. Aroma extract dilution analysis was carried out to determine the most prominent odorants. Using this targeted odorant-analytical approach, we identified 27 odorous substances representing diverse classes of molecules, including phenols with leather-like, horse stable-like or medicinal odors, acrylates eliciting glue-like, moldy and fruity impressions, and different esters with honey-like or effervescent tablet-like smells. These results show that the odor of acrylic adhesives results from a mixture of different odorants that cannot generally be traced back to the main constituents of the product but are rather likely to stem from impurities and trace side products and other contaminants

Zweidimensionale GC-MS/Olfaktometrie in der analytischen Sensorik

Klebstoffe werden häufig mit unangenehmen Gerüchen verbunden und können sich negativ auf die Qualität von Produkten ebenso wie auf die Qualität der Raumluft auswirken. Bereits während der Produktion können diese Geruchsstoffe freigesetzt werden und zu einer Geruchsbelastung am Arbeitsplatz führen. Dieser teils unangenehme Geruch ist jedoch bisher weitgehend unerforscht. Im Fraunhofer-Institut für Verfahrenstechnik und Verpackung IVV werden diese Gerüche des Alltags identifiziert und ihre Entstehung aufgeklärt. Damit Strategien zur Vermeidung dieser Gerüche entwickelt werden können, ist es nötig die geruchsaktiven Substanzen molekular zu erfassen