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Search Results: 1 - 10 of 3139 matches for " Christina Allmeling "
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Schwann Cell Metabolic Activity in Various Short-Term Holding Conditions: Implications for Improved Nerve Graft Viability
Insa Janssen,Kerstin Reimers,Christina Allmeling,Stella Matthes,Peter M. Vogt,Christine Radtke
International Journal of Otolaryngology , 2012, DOI: 10.1155/2012/742183
Abstract: Strategies for improvement of nerve regeneration and optimal conditions to prevent Schwann cell (SC) loss within a nerve transplant procedure are critical. The purpose of this study was to examine SC viability, which plays an important role in peripheral nerve regeneration, under various incubation conditions up to three hours. To address this issue, Schwann cell metabolic activity was determined using different independent test methods. The following experimental conditions were compared: SCs prepared from nerves were incubated in (1) isotonic saline solution (2) Dulbecco's modified Eagles medium as used for cell culturing, (3) Hannover bioreactor medium, and (4) Leibovitz's medium. SC metabolic activity of excised rat sciatic nerve was determined at 4°C, 18°C, and 37°C over 3 hrs. The results indicate that SC activity was optimized by the usage of Leibovitz's medium or HBRM at 37°C. Greater SC viability at the time of surgical nerve grafting could contribute to improved axonal regeneration and remyelination after nerve transplantation, and thus more successful functional recovery.
Schwann Cell Metabolic Activity in Various Short-Term Holding Conditions: Implications for Improved Nerve Graft Viability
Insa Janssen,Kerstin Reimers,Christina Allmeling,Stella Matthes,Peter M. Vogt,Christine Radtke
International Journal of Otolaryngology , 2012, DOI: 10.1155/2012/742183
Abstract: Strategies for improvement of nerve regeneration and optimal conditions to prevent Schwann cell (SC) loss within a nerve transplant procedure are critical. The purpose of this study was to examine SC viability, which plays an important role in peripheral nerve regeneration, under various incubation conditions up to three hours. To address this issue, Schwann cell metabolic activity was determined using different independent test methods. The following experimental conditions were compared: SCs prepared from nerves were incubated in (1) isotonic saline solution (2) Dulbecco's modified Eagles medium as used for cell culturing, (3) Hannover bioreactor medium, and (4) Leibovitz's medium. SC metabolic activity of excised rat sciatic nerve was determined at 4°C, 18°C, and 37°C over 3?hrs. The results indicate that SC activity was optimized by the usage of Leibovitz's medium or HBRM at 37°C. Greater SC viability at the time of surgical nerve grafting could contribute to improved axonal regeneration and remyelination after nerve transplantation, and thus more successful functional recovery. 1. Introduction Axonal regeneration and remyelination after peripheral nerve injury can be robust with significant functional recovery in contrast to the central nervous system where long white matter tract regeneration is absent or minimal [1]. After peripheral nerve transection, for example, after tumor resection, Wallerian degeneration characterized by macrophage infiltration, axonal membrane digestion, and retraction and proliferation of SCs occurs in the distal nerve segment [2]. The detached SCs from the degenerating axons upregulate the expression of nerve growth factor (NGF) and its low-affinity receptor p75NGFR [3]. For a period of time these SCs are activated [4] and provide trophic support for regeneration. Regeneration occurs from the proximal stump by axonal sprouting and elongation and continues into the distal stump or nerve transplant [5]. The status of a nerve transplant is critical for successful nerve regeneration. While nerve regeneration through Schwann-cell-enriched basal lamina tubes can reestablish connections with peripheral targets such as skin and muscle, a number of issues, such as navigation of axons across a complex nerve injury site where scarring can occur and appropriate targeting to peripheral end structures are major clinical concerns [6]. Although local endogenous SCs play an important role in regeneration of peripheral nerve, transplantation of additional Schwann cells into a lesion site was shown to assist this regenerative process [7,
Interactions between Spider Silk and Cells – NIH/3T3 Fibroblasts Seeded on Miniature Weaving Frames
Joern W. Kuhbier,Christina Allmeling,Kerstin Reimers,Anja Hillmer,Cornelia Kasper,Bjoern Menger,Gudrun Brandes,Merlin Guggenheim,Peter M. Vogt
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0012032
Abstract: Several materials have been used for tissue engineering purposes, since the ideal matrix depends on the desired tissue. Silk biomaterials have come to focus due to their great mechanical properties. As untreated silkworm silk has been found to be quite immunogenic, an alternative could be spider silk. Not only does it own unique mechanical properties, its biocompatibility has been shown already in vivo. In our study, we used native spider dragline silk which is known as the strongest fibre in nature.
Expression of TNF-related apoptosis-inducing ligand (TRAIL) in keratinocytes mediates apoptotic cell death in allogenic T cells
Kerstin Reimers, Christine Radtke, Claudia Y Choi, Christina Allmeling, Susanne Kall, Paul Kiefer, Thomas Muehlberger, Peter M Vogt
Annals of Surgical Innovation and Research , 2009, DOI: 10.1186/1750-1164-3-13
Abstract: Members of the TNF ligand family control and conduct numerous immunological and inflammation-related reactions. The Fas-FasL system and its associated mechanism of activation-induced cell death play an important role for the maintenance of hemostasis of the lymphoid system and the induction of immune tolerance [1]. The TNF-related apoptosis-inducing ligand (TRAIL) was identified as a homologue of the Fas-ligand (FasL) [2]. Yet, in contrast to FasL, TRAIL expression has been demonstrated in various tissues and organs [2-4], as the expression pattern of TRAIL receptors allows a subtle observation of apoptotic reactions. Until now, five different receptors for TRAIL have been described and all belong to the TNF receptor family. The receptors TRAIL-R1/DR4, TRAIL-R2/DR5, TRAIL-R3/DcR1 and TRAIL-R4/DcR2 exhibit a considerably homologous sequence of their extracellular domain and bind TRAIL as the only known ligand. The soluble receptor osteoprotegerin (OPG) belongs to a different sub-family and binds the ligand RANKL/OPGL as well. Following ligand binding and activation of cytoplasmatic death domains, TRAIL-R1 and TRAIL-R2 start series of signals for apoptosis [4,5], whereas the decoy receptors do not transmit death signals. The ratio of expression of DR4/DR5 and decoy receptors by a tumor cell will determine its sensibility for TRAIL-induced apoptosis [2,4]. An important function of TRAIL is the regulation of the immune response being involved in controlling the extent of the activated lymhocyte reaction [6]. Interactions between TRAIL and lymphocytes can create so-called immune-privileged sites, e.g. the placenta [7].The use of TRAIL for the induction of tolerance against allogenic transplants should be considered in burn medicine. The therapy of massive burn injuries is highly complex and can result in grave personal and socio-economic consequences. The therapeutic gold standard is the early resection of necrotic tissue and subsequent wound coverage with autologous ski
Bundles of Spider Silk, Braided into Sutures, Resist Basic Cyclic Tests: Potential Use for Flexor Tendon Repair
Kathleen Hennecke, Joern Redeker, Joern W. Kuhbier, Sarah Strauss, Christina Allmeling, Cornelia Kasper, Kerstin Reimers, Peter M. Vogt
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061100
Abstract: Repair success for injuries to the flexor tendon in the hand is often limited by the in vivo behaviour of the suture used for repair. Common problems associated with the choice of suture material include increased risk of infection, foreign body reactions, and inappropriate mechanical responses, particularly decreases in mechanical properties over time. Improved suture materials are therefore needed. As high-performance materials with excellent tensile strength, spider silk fibres are an extremely promising candidate for use in surgical sutures. However, the mechanical behaviour of sutures comprised of individual silk fibres braided together has not been thoroughly investigated. In the present study, we characterise the maximum tensile strength, stress, strain, elastic modulus, and fatigue response of silk sutures produced using different braiding methods to investigate the influence of braiding on the tensile properties of the sutures. The mechanical properties of conventional surgical sutures are also characterised to assess whether silk offers any advantages over conventional suture materials. The results demonstrate that braiding single spider silk fibres together produces strong sutures with excellent fatigue behaviour; the braided silk sutures exhibited tensile strengths comparable to those of conventional sutures and no loss of strength over 1000 fatigue cycles. In addition, the braiding technique had a significant influence on the tensile properties of the braided silk sutures. These results suggest that braided spider silk could be suitable for use as sutures in flexor tendon repair, providing similar tensile behaviour and improved fatigue properties compared with conventional suture materials.
Artificial Skin – Culturing of Different Skin Cell Lines for Generating an Artificial Skin Substitute on Cross-Weaved Spider Silk Fibres
Hanna Wendt,Anja Hillmer,Kerstin Reimers,Joern W. Kuhbier,Franziska Sch?fer-Nolte,Christina Allmeling,Cornelia Kasper,Peter M. Vogt
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0021833
Abstract: In the field of Plastic Reconstructive Surgery the development of new innovative matrices for skin repair is in urgent need. The ideal biomaterial should promote attachment, proliferation and growth of cells. Additionally, it should degrade in an appropriate time period without releasing harmful substances, but not exert a pathological immune response. Spider dragline silk from Nephila spp meets these demands to a large extent.
Spider Silk Constructs Enhance Axonal Regeneration and Remyelination in Long Nerve Defects in Sheep
Christine Radtke,Christina Allmeling,Karl-Heinz Waldmann,Kerstin Reimers,Kerstin Thies,Henning C. Schenk,Anja Hillmer,Merlin Guggenheim,Gudrun Brandes,Peter M. Vogt
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0016990
Abstract: Surgical reapposition of peripheral nerve results in some axonal regeneration and functional recovery, but the clinical outcome in long distance nerve defects is disappointing and research continues to utilize further interventional approaches to optimize functional recovery. We describe the use of nerve constructs consisting of decellularized vein grafts filled with spider silk fibers as a guiding material to bridge a 6.0 cm tibial nerve defect in adult sheep.
What Reasons Might the Other One Have?—Perspective Taking to Reduce Psychological Reactance in Individualists and Collectivists  [PDF]
Christina Steindl, Eva Jonas
Psychology (PSYCH) , 2012, DOI: 10.4236/psych.2012.312A170
Abstract:

Previous research has demonstrated a considerable amount of negative consequences resulting from psychological reactance. The purpose of this study was to explore opportunities to reduce the amount of reactance. Using the method of perspective taking as an intervention, the current study of 196 Austrians and 198 Filipinos examined whether reactance could be reduced and whether individualists and collectivists differ concerning reactance and their perspective taking abilities. Our results indicated that participants who took the perspective of the person who threatened them experienced less reactance than participants who did not take this approach. This was the case for people from both cultural backgrounds. Nevertheless, comparisons among the two cultural groups yielded different reactions to restrictions. This indicates that individualists are more sensitive to a self-experienced restriction than collectivists, but less sensitive to a restriction of another person. Consequently, we consider culture to be a crucial determinant in predicting the amount of reactance.

Current Treatment of DCIS  [PDF]
Christina Choy, Kefah Mokbel
Journal of Cancer Therapy (JCT) , 2014, DOI: 10.4236/jct.2014.52022
Abstract:

Abstract: Ductal carcinoma in-situ DCIS is a heterogeneous entity in breast neoplasm with unpredictable biological behavior. This poses challenge in the management of DCIS. Various trials on DCIS have shown good outcome with integral treatment of adequate surgery, radiotherapy and hormonal therapy. Identification of subgroup of DCIS for radiotherapy and hormonal therapy could improve recurrence rate, contralateral tumours incidence and perhaps overall survival. Various risk score calculations could help to direct radiotherapy and hormonal treatment verses surgery alone and to avoid over treatment. Oncotype DX assay could be a new way of risk calculation to direct types of DCIS treatment. The recent increased use of MRI could increase the detection of DCIS and a more accurate extent of disease estimation. This article is a summary of major literatures and major trials result for DCIS.

Influences on the Marking of Examinations  [PDF]
Christina Bermeitinger, Benjamin Unger
Psychology (PSYCH) , 2014, DOI: 10.4236/psych.2014.52014
Abstract:

In the present work, we examined a phenomenon highly relevant in the educational field for assessing or judging performance, that is, the question how the second examiner’s marking is influenced by the evaluation of the first examiner. This phenomenon is known as anchoring in cognitive psychology. In general, in anchoring effects numeric information (i.e., the anchor) pulls estimations or judgments towards the anchor. One domain which is highly important in real life has been investigated only occasionally, that is, the marking of examinations. In three experiments, participants were asked to evaluate a written assignment. The mark (either good or bad) of a ficticious first examiner was used as the anchor. We found clear anchoring effects that were unaffected by feedback in a preceding task (positive, neutral, negative) or the expert status of the presumed first examiner. We discussed the problems related to this effect.

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