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  • 1
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Experimental dermatology 9 (2000), S. 0 
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: We have analysed the consequences of liposome mediated gene transfer into human primary epidermal keratinocytes and compared non-Epstein–Barr Virus (EBV) and EBV based expression vectors that carry the genes encoding human Growth Hormone (hGH) or Enhanced Green Fluorescent Protein (EGFP). Different kinetics between the non-EBV and EBV based vectors were revealed upon subcultivation of hGH transfected keratinocytes. The keratinocytes transfected with non-EBV based vector showed a rapid reduction in hGH production. Although the EBV based vector resulted in more stable expression, this was also reduced over time. Chromatin inactivation by deacetylation was investigated by treatment with sodium butyrate and found not to be the reason for the decreasing expression. Keratinocytes divided into subpopulations enriched for either stem cells or transit amplifying cells, based on β1-integrin expression and function, do not differ significantly with respect to susceptibility to productive transfection. However, when the keratinocytes were transfected with the EGFP gene and sorted live by FACS into EGFP negative and positive populations, only the negative cells were capable of forming significant numbers of colonies. This is consistent with the observation that the ability to incorporate BrdU was dramatically reduced in the EGFP expressing population within 24–48 h post transfection indicating an almost complete cell cycle arrest. p53 levels were unaffected by the procedures, and the keratinocyte cell line HaCat, mutated in both p53 alleles, also shows a marked reduction in clonogenic potency upon transfection. There was a slight increase of TUNEL positive apoptotic nuclei in the positive population at early time points. However, the apoptotic index was still very low. When we measured the frequency of involucrin expressing cells, we found an increase in the productively transfected population over time indicating an initiation of terminal differentiation. In contrast to the transfected cultures, keratinocytes that were transduced using a retroviral vector showed no decrease in colony forming efficiency. In conclusion we find that transgene expressing cells from transfected cultures of epidermal keratinocytes undergo cell cycle arrest and initiate terminal differentiation by mechanisms which are independent of p53 levels.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Science Ltd/Inc.
    Scandinavian journal of immunology 59 (2004), S. 0 
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In our laboratory, we have developed a database system, which we believe is of immediate interest to the general scientific community. The database represents a computer-based replacement for the laboratory notebooks used in the majority of research laboratories worldwide. In addition, the database provides an effective tool for organizing and managing laboratory information at all levels, spanning from managing and revising standard operating procedures and producing documentation of research activities to keeping track of data and conclusions. Using the commercially available database toolkit software FileMaker Pro, we have developed a relational database solution for management of laboratory information. The system consists of a hierarchy of five interrelated databases, each pertaining to a separate type of information, namely, overall project information, information relating to individual experiment setups, documentation of daily research activity, generated data and descriptions of standard operating procedures. Like other databases, each individual database consists of a number of records, each comprised of a set of fields in which information is entered. In each record, a certain field is reserved to specify the relation of the record to a record in another database at a higher level. Thus, the database is essentially five databases linked by a hierarchy of one-to-many relations, organizing information in a folder-like structure. Importantly, the database system allows multiple users to access and edit records simultaneously, and the data entered in one database immediately becomes accessible through the other databases. The limitations of laboratory notebooks are apparent when looking for information, which is dispersed throughout one or more notebooks, or possibly on loose sheets of paper or printouts ‘somewhere’. The often complicated process of gathering laboratory data or results when writing grant applications or research papers is made considerably easier with the database system. Thus, the database solution presented should be broadly attractive to researchers, irrespective of their scientific discipline.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden , USA : Blackwell Science Ltd
    Scandinavian journal of immunology 59 (2004), S. 0 
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Flow cytometric measurement of intracellular cytokines in T cells exposed to antigen is a widely used method for quantification of an antigen-specific T-cell response. As the frequency of antigen-specific T cells is often very low, any improvement in signal to noise ratio is of great importance. Thus, in this study, the ability of antigen-pulsed dendritic cells (DCs) to increase the number of antigen-specific, interferon-γ (IFN-γ)-producing CD4+ T cells measurable both in fresh peripheral blood and in reconstituted frozen blood mononuclear cell (MNC) samples was evaluated. Cytomegalovirus (CMV) was used as antigen in a 10 h assay, using cells from both CMV-seropositive and -seronegative donors. When reconstituted frozen samples were analysed, the general response towards CMV lysate in CMV-seropositive donors was 23–86% lower compared to the corresponding fresh blood samples. Antigen-pulsed DCs could not improve the sensitivity of the intracellular cytokine-detection assay when fresh peripheral blood samples were used. Interestingly, however, the addition of CMV lysate-pulsed DCs to cryopreserved MNC samples substantially increased the frequency of specifically induced IFN-γ-producing cells to a level comparable to the frequency found in the corresponding fresh blood samples.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European food research and technology 210 (1999), S. 114-118 
    ISSN: 1438-2385
    Keywords: Key words Glazing ; Freeze-stable ; Bake stable ; Differential scanning calorimetry ; Glass transition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  A freeze- and bake-stable glazing for pastry has been developed based on an optimization procedure in which starches and carrageenans as thickening agents were combined with sugar alcohols and sodium tripolyphosphate. Instrumental gloss measurement on test biscuits showed that glazing consisting of 3% ι-carrageenan and 15% sorbitol (w/w) had maximal gloss. This was confirmed on pastry products. In contrast to glazing based on mannitol, no crystallization problems were encountered for this glazing, for which differential scanning calorimetry showed that some water freezes at –3  °C followed by freezing of supercooled encapsulated water at –20  °C and by a glass transition at –61  °C. During normal frozen storage of preglazed, nonbaked pastry, the glazing is thus in a nonstable rubbery state with a limited resistance to water migration and ice crystal formation, which can be substantially improved by storage at temperatures below –61  °C.
    Type of Medium: Electronic Resource
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