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Muller F.-J.,Zentrum fur Integrative Psychiatrie | Schuldt B.M.,RWTH Aachen | Williams R.,Sanford Burnham Institute for Medical Research | Mason D.,Independent Consultant | And 11 more authors.
Nature Methods | Year: 2011

Pluripotent stem cells (PSCs) are defined by their potential to generate all cell types of an organism. The standard assay for pluripotency of mouse PSCs is cell transmission through the germline, but for human PSCs researchers depend on indirect methods such as differentiation into teratomas in immunodeficient mice. Here we report PluriTest, a robust open-access bioinformatic assay of pluripotency in human cells based on their gene expression profiles. © 2011 Nature America, Inc. All rights reserved.

Becker T.,University of Lubeck | Becker T.,Fraunhofer Research Institution for Marine Biotechnology | Madany A.,University of Lubeck
Methods of Information in Medicine | Year: 2012

Objectives: The cultivation of adherently growing cell populations is a major task in the field of adult stem cell production used for drug discovery and in the field of regenerative medicine. To assess the quality of a cell population, a crucial event is the mitotic cell division: the precise knowledge of these events enables the reconstruction of lineages and accurate pro - liferation curves as well as a detailed analysis of cell cycles. To serve in an autonomous cell farming framework, such a detector requires to work reliably and unsupervised. adapts to the 3 phases of cell growth (lag, log and stationary phase). As a concurrent model, we compared ML with kernel SVMs using linear, quadratic and Gaussian kernel functions. All approaches are evaluated for their ability to distinguish between mitotic and nonmitotic events. The large, publicly available benchmark data CeTReS (reference data set A with > 240,000 segmented cells, > 2,000 mitotic events) is used for this evaluation. Results: The adaptive (unsupervised) ML approach clearly outperforms previously published non-adaptive approaches and the linear SVM. Furthermore, it robustly reaches a performance comparable to quadratic and Gaussian SVM. Conclusions: The proposed simple and label free adaptive variant might be the method of choice when it comes to autonomous cell farming. Hereby, it is essential to have reliable and unsupervised mitosis detection that covers all phases of cell growth. © Schattauer 2012.

Mehnert J.M.,Fraunhofer Research Institution for Marine Biotechnology
Cellular Physiology and Biochemistry | Year: 2014

Background/Aims: The treatment of peripheral nerve lesions still represents a clinical challenge. Several approaches such as novel biomaterials for nerve guides, addition of growth factors or cellular supplements moved in the focus of research. Especially the application of autologous stem cells is highly promising for future applications. Human sweat gland derived stem cells (hSGSCs) represent an easy accessible source of autologous adult stem cells and did already show a beneficial effect in dermal wound healing. Methods: In this study, the effect of hSGSCs on neurite outgrowth of primary adult or prenatal Dorsal root ganglia (DRG) neurons was analysed in an indirect co-culture model. Additionally, direct co-cultures with hSGSCs as a feeder layer were performed. Results: Adult and prenatal DRG neurons showed increased neurite outgrowth after 24 h co-culture with hSGSCs. The outgrowth increased significantly by the factors 5.6 and 2.6 respectively. Direct co-cultures revealed neurite alignment along the hSGSCs orientation. Conclusion: The paracrine influence of hSGSCs on neurite outgrowth, but also their ability to operate as a feeder layer with guidance properties shows great potential for future applications in peripheral nerve regeneration. © 2014 S. Karger AG, Basel Copyright © 2014, S. Karger AG. All rights reserved.

Rakers S.,Fraunhofer Research Institution for Marine Biotechnology | Niklasson L.,Gothenburg University | Steinhagen D.,Leibniz University of Hanover | Kruse C.,Fraunhofer Research Institution for Marine Biotechnology | And 4 more authors.
Journal of Investigative Dermatology | Year: 2013

Mammalian and fish skin share protective activities against environments that are rich in infectious agents. Fish epidermis is endowed with an extrinsic barrier consisting of a mucus layer and antimicrobial peptides (AMPs). These operate together as a protective chemical shield. As these AMPs are evolutionarily well preserved and also found in higher vertebrate skin (including human epidermis), fish skin offers a unique opportunity to study the origins of innate antimicrobial defense systems. Furthermore, the broad spectrum of fish mucus antimicrobial activities renders piscine AMPs interesting to investigative dermatology, as these may become exploitable for various indications in clinical dermatology. Therefore, this article aims at casting light on fish mucus, the evolutionary relationship between human and fish AMPs, and the latter's antibacterial, antifungal, and even antiviral activities. Moreover, we develop dermatological lessons from, and sketch potential future clinical applications of, fish mucus and piscine AMPs. © 2013 The Society for Investigative Dermatology.

Danner S.,Fraunhofer Research Institution for Marine Biotechnology | Benzin H.,Fraunhofer Research Institution for Marine Biotechnology | Vollbrandt T.,University of Lubeck | Oder J.,Fraunhofer Research Institution for Marine Biotechnology | And 2 more authors.
International Journal of Cell Biology | Year: 2013

With the increasing relevance of cell-based therapies, there is a demand for cell-labeling techniques for in vitro and in vivo studies. For the reasonable tracking of transplanted stem cells in animal models, the usage of quantum dots (QDs) for sensitive cellular imaging has major advances. QDs could be delivered to the cytoplasm of the cells providing intense and stable fluorescence. Although QDs are emerging as favourable nanoparticles for bioimaging, substantial investigations are still required to consider their application for adult stem cells. Therefore, rat pancreatic stem cells (PSCs) were labeled with different concentrations of CdSe quantum dots (Qtracker 605 nanocrystals). The QD labeled PSCs showed normal proliferation and their usual spontaneous differentiation potential in vitro. The labeling of the cell population was concentration dependent, with increasing cell load from 5 nM QDs to 20 nM QDs. With time-lapse microscopy, we observed that the transmission of the QD particles during cell divisions was random, appearing as equal or unequal transmission to daughter cells. We report here that QDs offered an efficient and nontoxic way to label pancreatic stem cells without genetic modifications. In summary, QD nanocrystals are a promising tool for stem cell labeling and facilitate tracking of transplanted cells in animal models. © 2013 S. Danner et al.

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