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Repair Strategies (repair + strategy)
Selected AbstractsThe Art of Repair in Surgical Hair Restoration Part I: Basic Repair StrategiesDERMATOLOGIC SURGERY, Issue 9 2002Robert M. Bernstein MD background. An increasingly important part of many hair restoration practices is the correction of hair transplants that were performed using older, outdated methods, or the correction of hair transplants that have left disfiguring results. The skill and judgment involved in these repair procedures often exceed those needed to operate on patients who have had no prior surgery. The use of small grafts alone does not protect the patient from poor work. Errors in surgical and aesthetic judgment, performing procedures on noncandidate patients, and the failure to communicate successfully with patients about realistic expectations remain major problems. objective. This two-part series presents new insights into repair strategies and expands upon several techniques previously described in the hair restoration literature. The focus is on creative aesthetic solutions to solve the supply/demand limitations inherent in most repairs. This article is written to serve as a guide for surgeons who perform repairs in their daily practices. methods. The repairs are performed by excision with reimplantation and/or by camouflage. Follicular unit transplantation is used for the restorative aspects of the procedure. results. Using punch or linear excision techniques allows the surgeon to relocate poorly planted grafts to areas that are more appropriate. In special situations, removal of grafts without reimplantation can be accomplished using lasers or electrolysis. The key elements of camouflage include creating a deep zone of follicular units, angling grafts in their natural direction, and using forward and side weighting of grafts to increase the appearance of fullness. The available donor supply is limited by hair density, scalp laxity, and scar placement. conclusion. Presented with significant cosmetic problems and severely limited donor reserves, the surgeon performing restorative hair transplantation work faces distinct challenges. Meticulous surgical techniques and optimal utilization of a limited hair supply will enable the surgeon to achieve the best possible cosmetic results for patients requiring repairs. [source] The morphological development of neurons derived from EGF- and FGF-2-driven human CNS precursors depends on their site of integration in the neonatal rat brainEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2000Anne E. Rosser Abstract Neural precursor cells derived from the developing human brain were expanded in vitro under the influence of fibroblast growth factor-2 (FGF-2) and epidermal growth hormone (EGF), and were then transplanted into different regions of the neonatal rat brain. Four weeks later neurons were seen to have developed from human embryonic precursors, using a human-specific antibody to tau (htau). There were morphological differences between implanted neurons developing in the hippocampus, striatum and neocortex, which were confirmed by cell volume measurements, although no specific neurochemical phenotypes were identified. Htau-positive fibres were seen to project extensively along fibre pathways appropriate for the site of neuronal integration. This study demonstrates that, following cell division in vitro, neurons differentiating from human precursor cell populations retain the ability to respond appropriately to regional determinants present in the neonatal rat brain. This is important for the application of such cells in CNS repair strategies, in particular neural transplantation. [source] Lack of oxygen in articular cartilage: consequences for chondrocyte biologyINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 2 2010Jérôme E. Lafont Summary Controlling the chondrocytes phenotype remains a major issue for cartilage repair strategies. These cells are crucial for the biomechanical properties and cartilage integrity because they are responsible of the secretion of a specific matrix. But chondrocyte dedifferentiation is frequently observed in cartilage pathology as well as in tissue culture, making their study more difficult. Given that normal articular cartilage is hypoxic, chondrocytes have a specific and adapted response to low oxygen environment. While huge progress has been performed on deciphering intracellular hypoxia signalling the last few years, nothing was known about the particular case of the chondrocyte biology in response to hypoxia. Recent findings in this growing field showed crucial influence of the hypoxia signalling on chondrocytes physiology and raised new potential targets to repair cartilage and maintain tissue integrity. This review will thus focus on describing hypoxia-mediated chondrocyte function in the native articular cartilage. [source] Cambium cell stimulation from surgical release of the periosteumJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2003Timothy M. Simon An autograft of periosteal tissue containing cambium cells has potential to become chondrogenic or osteogenic depending on the regeneration repair strategies. The potential number of harvestable cambium cells diminishes with age. Other factors may be associated with a reduction in the number or variable yields of cambium cells including harvest technique, harvest site location, and the time interval from harvest to implantation. Attempts to increase the number of cambium cells have included improvements in harvesting and handling technique, and expansion of the cells in tissue culture. An ,in situ" stimulation and proliferation technique would offer the potential for increasing the number of cambium cells in a cost-effective manner for transplantation without the need for expansion in tissue culture. The hypothesis tested was that surgical release of the periosteum and its deep inner underlying cambium layer by sharply incising through the superficial periosteal fibrous layer down to and scoring the cortical bone surface would increase the number of cambium cells that could be harvested at a later time period. Two techniques for periosteal release were used to stimulate a proliferation of the underlying cambium layer and increase the cambium cells for harvest in skeletally mature goats: (1) sharply scoring all four-sides of the tissue test site perimeter, and (2) sharply scoring only two sides of the tissue test site. The two-sided and four-sided release scoring of the periosteum induced stimulatory responses in the number of cambium cells. In addition, a marked increase in mRNA expression for BMP-2 (p < 0.001) was observed within 24 h and remained elevated over baseline values for up to 96 h after this stimulation to the cambium layer. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Two-dimensional failure modeling with minimal repairNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 3 2004J. Baik In this paper, we discuss two-dimensional failure modeling for a system where degradation is due to age and usage. We extend the concept of minimal repair for the one-dimensional case to the two-dimensional case and characterize the failures over a two-dimensional region under minimal repair. An application of this important result to a manufacturer's servicing costs for a two-dimensional warranty policy is given and we compare the minimal repair strategy with the strategy of replacement of failure. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004. [source] | |||||||||||||