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  • 1
    Electronic Resource
    Electronic Resource
    Knorpelknochentransplantation versus autogene Chondrocytentransplantation Eine prospektive vergleichende klinische Studie (2000)
    Springer
    Der Chirurg 71 (2000), S. 1090-1097 
    Details
    ISSN: 1433-0385
    Keywords: Schlüsselwörter: Gelenkknorpeldefekt ; autologe Chondrocytentransplantationen ; autogene osteochondrale Transplantationen ; Knorpelbiologie. ; Keywords: Full-thickness cartilage defect ; Autologous chondrocyte transplantation ; Autologous osteochondral transplantation ; Cartilage biology.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract. Introduction: The treatment of full-thickness cartilage defects still represents a problem that has not yet been solved satisfactorily. Current methods used to cover defects in the knee joint are osteochondral cylinder transplantation (OCT) and autologous chondrocyte transplantation (ACT). Methods: With a prospective clinical investigation, at the time being with 2-year results, we have examined ACT in comparison to OCT in 20 patients with regard to clinical and histomorphological (histology, immunohistochemistry, RES) outcome. Results: We found equally good results with both methods in Lysholm, Meyers and Tegner Activity Scores. Histomorphologic evaluation of biopsies obtained by arthroscopy after ACT showed a defect filling in all cases, mainly with fibrous cartilage, while localized areas of hyalinelike regenerative cartilage were documented near the base.We did not see any histomorphologically visible change in the transplants after OCT. Conclusion: At the time we prefer OCT instead of ACT given the correct indication.
    Notes: Zusammenfassung. Einleitung: Die Behandlung tiefreichender Knorpelschäden stellt nach wie vor ein noch nicht zufriedenstellend gelöstes Problem dar. Aktuelle Methoden zur Defektdeckung am Kniegelenk sind die osteochondrale Zylindertransplantation (OCT) und die autogene Chondrocytentransplantation (ACT). Methoden: Im Rahmen einer prospektiv angelegten klinischen Untersuchung mit derzeit 2 Jahresergebnissen haben wir die ACT im Vergleich zur OCT bei jeweils 20 Patienten hinsichtlich des klinischen und histomorphologischen (Histologie, Immunhistochemie, RES ) Outcome überprüft. Ergebnisse: Hierbei fand sich bei beiden Methoden im Lysholm-, Meyers- sowie dem Tegner-Aktivitäts-Score ein gleich gutes Ergebnis. Die histomorphologische Auswertung der arthroskopisch gewonnenen Biopsierate nach ACT zeigten eine Defektfüllung vornehmlich mit Faserknorpel, wobei basisnah sich begrenzte Areale hyalinähnlicher Knorpelregenerate nachweisen ließen. Eine histomorphologisch erkennbare Veränderung der Transplantate nach OCT sahen wir nicht. Schlußfolgerung: Die OCT wird derzeit von uns der ACT bei korrekter Indikationsstellung vorgezogen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001040051184
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of single-dose versus fractionated irradiation on the suppression of heterotopic bone formation – an animal model-based follow-up study in rats (2000)
    Springer
    Archives of orthopaedic and trauma surgery 120 (2000), S. 575-581 
    Details
    ISSN: 1434-3916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The histological and enzymatic effects of single-dose irradiation of 7 Gray (Gy) versus fractionated irradiation of 5 × 2 Gy on the suppression of heterotopic ossification were examined over a period of 60 days in adult male Wistar rats (n = 57). The standardized osteogenesis model system in rats [9, 10, 11, 16, 19] was used for this purpose. The course of developing ossifications was documented quantitatively and qualitatively by means of quantitative computed tomography/osteodensitometry and digital luminescence radiography. Assessment of the activities of the enzymes alkaline and acid phosphatase throughout the experiment as well as characterization of the isoenzyme of alkaline phosphatase (AP) in connection with histological observations displayed a metaplasia of the ingrowing connective tissue into bone-typical cells during osteoinduction. Thus, the increase of AP is the first sign of a functional transformation of mesenchymal stem cells into chondroid bone cells. The increase in the acid phosphatase level with a maximum of acitivity between the 15th and 30th day (according to the respective treatment group) is highly suggestive of a remodeling process paralleling incipient chondroclast and osteoclast activity. In the animal groups undergoing irradiation, the above-mentioned increase of enzymes occurred after a delay. Furthermore, the maximum values observed were lower than those in the group not undergoing irradiation. Both findings were more manifest in the animal group which underwent 5 × 2 Gy of radiation than in the group which underwent single-dose irradiation of 7 Gy. Radiation suppresses matrix-induced osteogenesis. The histological and enzymatic course of this process was unchanged in the animals which did not undergo irradiation. However, it was quantitatively reduced and accompanied by a retardation of osteogenesis. Both effects were again reduced with fractionated irradiation of 5 × 2 Gy, which is theoretically dose-equivalent to a 1 × 7 Gy application. Histological examinations revealed damage to the migratory, proliferating mesenchymal stem cell population by irradiation doses which had relatively small effects on preosteoblasts, osteoblasts, chondroblasts and other specialized cell forms. Therefore, it may be concluded that the smaller degree of heterotopic ossification in the irradiated groups was due to damage of and a decrease in the number of mesenchymal stem cells at the implant site. Our results stress the necessity of instituting postoperative irradiation therapy as early as possible to prevent heterotopic ossification. In view of experimentally proven better effects, fractionated irradiation has to be preferred to a dose-equivalent single-dose radiation, especially considering the fewer side-effects noted with fractionated irradiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004020000178
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  • 3
    Electronic Resource
    Electronic Resource
    Bone morphogenetic protein: a review (1991)
    Springer
    International orthopaedics 15 (1991), S. 169-177 
    Details
    ISSN: 1432-5195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Le potentiel ostéogénique de l'os et de la matrice osseuse a été longtemps caractérisé uniquement par ses effets biologiques et les paramètres qui l'influencent. Récemment la capacité ostéo-inductrice de la matrice osseuse a été définie chimiquement par l'identification d'une protéine osseuse morphogènétique (POM) et des facteurs ostéogéniques de différents types ont été individualisés. L'état actuel de l'isolement, de la purification, et de la caractérisation de ces facteurs est résumé dans cette mise au point. On y rapporte les aspects généraux de l'isolement et de l'appréciation des préparations de POM ainsi que les résultats de l'application d'implants de POM, y compris en clinique.
    Notes: Summary The osteogenic potential of bone and bone matrix has been characterised only by its biological effects and the parameters influencing it. Recently, the osteoinductive ability of bone matrix had been defined chemically by the description of a bone morphogenetic protein (BMP), and the parameters of osteogenic factors from different species have now been recognised. The current state of isolation, purification and characterisation of these factors is summarised in this review. General aspects of the isolation and testing of BMP preparations, and the results of orthotopic application of BMP implants, including clinical cases, are reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00179720
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