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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neurology 74 (1922), S. 248-250 
    ISSN: 1432-1459
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0827
    Keywords: Key words: Heterotopic osteoblast-like cells — Colony formation — Differentiation — Alkaline phosphatase — Osteocalcin.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. In this study, a characterization of human bone-forming cells responsible for heterotopic ossification was carried out in vitro. The biological and biochemical cell characteristics of the heterotopic osteoblast-like (HOB) cells were compared with those of orthotopic osteoblast-like (OB) cells from normal bone and stromal bone marrow cells believed to contain a subpopulation of osteogenic precursor cells. We found that HOB's from the spongiosa of heterotopic ossification required less time until the beginning of migration and the achievement of confluence in vitro compared with OBs from femoral shaft spongiosa. The fraction of mitotically active cells assessed by a clonogenic assay was higher as well in HOB cells. The in vitro studies of mitogenesis and the efficiency of colony formation of osteogenic cells indicate that with increasing differentiation and relative age they become more dependent on growth factors in the medium, otherwise the morphology of osteoblast-like cells changes and they pass irreversibly into the postmitotic stage of the cell cycle. The activity of the alkaline phosphatase is distinctly higher in the HOB than in the OB cells, HOB cells exhibit a lower level of osteocalcin expression compared with OB cells. No significant difference was found between OB and HOB cells in the amount of procollagen of type I sequestered by the cells. After 30 days, HOB and OB cells formed a mineralized matrix on exposure to 2 mM β-glycerophosphate. Since HOBs were isolated from heterotopic bone that had developed within 3–6 months after hip surgery, the differences in cellular behavior compared with OBs may be attributed to the relatively young age of HOB cells.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International orthopaedics 15 (1991), S. 169-177 
    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
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  • 4
    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
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  • 5
    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
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Der Orthopäde 27 (1998), S. 80-88 
    ISSN: 1433-0431
    Keywords: Key words Demineralized bone matrix (DBM) • Bone formation • Fluorescence histology • Hydroxylapatite • Histomorphometry • Mini pigs ; Schlüsselwörter Demineralisierte Bone-Matrix • Knochenneubildung • Fluoreszenzhistologie • Hydroxylapatitkeramik • Histomorphometrie • Minischwein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Das Hauptziel dieser Arbeit war es, in vergleichenden Untersuchungen am Minischwein die Stimulation der Knochenheilung im ersatzstarken Lager durch demineralisierte „bone-matrix-chips“ (DBM) sowie DBM-Gel (Grafton) gegen die knöcherne Integration einer Hydroxylapatitkeramik (Endobon) zu untersuchen. Folgende Ergebnisse konnten erzielt werden: 1. Allogene DBM in Chips- und in Gelform hatte keine osteostimulative Wirkungen auf die Knochenheilung im ersatzstarkem Lager. Nach 12 Wochen war der Defekt bei beiden Applikationsarten der DBM noch nicht knöchern durchbaut. 2. Der Knocheneinwuchs bis zum 35. Tag bei der Pressfit-implantierten HA-Keramik Endobon war nur randständig, während nach 12 Wochen die Keramik vollständig knöchern durchbaut war. Es kam zu einem engen Keramikknochenverbund. 3. Diese Ergebnisse im Rahmen der vorliegenden tierexperimentellen Untersuchung konnten durch eine zeitgerechte Dynamik der Knochenneu- und -umbildungen anhand von histologischen Fluoreszenzübersichten ermittelt werden. Die zeitliche Bestimmung der Knocheneinheilrate wurde durch tägliche Markierung der Tiere mit fluoreszierenden Farbstoffen ermöglicht.
    Notes: Summary The aim of this study was to evaluate the bone stimulation forced by Demineralized Bone Matrix (DBM)-Chips and – Gel in comparison to the bone –ingrowth into a porous hydroxylapatite ceramic (Endobon) in mini pigs. The following results were obtained: 1. DBM-Chips and DBM-Gel did not stimulate bone healing when filled into cancellous bone defects. The defect did not heal within 12 weeks. 2. Up to 35 days the least amount of new bone formation was observed within porous hydroxylapatite ceramic. Up to 12 weeks completly bone ingrowth in to the ceramic has been seen with close bonding between new formed bone and the ceramic trabeculae. 3. By continuous labelling with fluorochromes the new bone formation could be analysed by fluorescence microscopy and the dynamics could be related to time after implantation.
    Type of Medium: Electronic Resource
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