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Purpose: Bone block augmentation from the iliac crest can be used for reconstruction of the osteochondral unit to restore the underlying subchondral bone upon restoration of the cartilaginous layer via matrix-induced chondrocyte transplantation. To critically understand the successful restoration of the defect, biomechanical and histological analysis of the implanted bone blocks is required. The aim of the study was to analyse the ability of the bone block technique to restore huge bone defects by mimicking the physiological subchondral zone.Methods: The experiments were performed using lateral femoral condyles and iliac crest bone grafts from the same cadavers (n = 6) preserved using the Thiel method. CT scans were made to evaluate bone pathology. Bone mineral density of all specimens was evaluated in the femoral head prior to testing. A series of tests were conducted for each pair of specimens. A static compression test was performed using an electro dynamic testing machine with maximal strength and failure behavior analyzed. Biomechanical tests were performed in the medial-lateral direction for iliac crest and for femoral condyles with and without removal of the cartilage layer. Histological analysis was performed on decalcified specimens for comparison of the condyle at lesion site and the graft.Results: No significant difference in failure load could be found for iliac crest (53.3-180.5 N) and femoral condyle samples upon cartilage removal (38.5-175.1 N) (n.s.). The femoral condyles with an intact cartilage layer showed significantly higher loads (118.3-260.4N) compared to the other groups indicating that native or regenerated cartilage can further increase the failure load (p < 0.05). Bone mineral density significantly influenced failure load in all study groups (p < 0.05). Histological similarity of the cancellous bone in the femoral condyle and in the iliac crest was observed. However, within the subchondral zone, there was a higher density of sponge like organized trabeculae in the bone samples from the iliac crest. Tide mark was only detected at the osteochondral interface in femoral condyles.Conclusion: This study demonstrated that, bone blocks derived from the iliac crest allow a biomechanical appropriate and stable restoration of huge bony defects by resembling the subchondral zone of the femoral condyle. Therefore, bone augmentation from the iliac crest combined with matrix-induced autologous chondrocyte transplantation seems to be a reasonable method to treat these challenging injuries. [ABSTRACT FROM AUTHOR]

This study examined the effects of low intensity pulsed ultrasound (LIPUS) on human bone marrow-derived mesenchymal stem cells undergoing chondrogenic differentiation. Aggregates of mesenchymal stem cells and mesenchymal stem cells seeded in three dimensional matrices were cultured in a defined chondrogenic medium and subjected to LIPUS for the first 7 days of culture. At 1, 7, 14 and 21 days, samples were harvested for histology, immunohistochemistry, RT-PCR, and quantitative DNA and matrix macromolecule analysis. Cell aggregates with daily treatment for 20 minutes showed no significant differences for proteoglycan and collagen content during chondrogenic differentiation. However ultrasound application for 40 minutes daily resulted in a statistically significant increase of the proteoglycan and collagen content after 21 days in culture. Aggregates treated for 20 minutes daily showed decreased expression of chondrogenic genes at all time points. In contrast, 40 minutes of daily treatment of aggregates resulted in a significant increase of chondrogenic marker genes after an initial decrease at day 7 with time in culture. Ultrasound treated cell-scaffold constructs showed a significant increase of chondrogenic marker gene expression and extracellular matrix deposition. This study indicates that LIPUS can be used to enhance the chondrogenesis of mesenchymal stem cells in cell aggregates and cell-scaffold constructs. We have found a dependency on the specific treatment parameters. We hypothesize that LIPUS can be used for an improved in vitro preparation of optimized tissue engineering implants for cartilage repair. Furthermore this non-invasive method could also be of potential use in vivo for regenerative therapy of cartilage in the future. [ABSTRACT FROM AUTHOR]

Articular cartilage possesses little capacity for endogenous repair after having been damaged by disease or trauma. Various surgical procedures depending on ingrowth of mesenchymal stem cells into the defects showed repair with fibrocartilage which is of minor quality and less resistant against physical forces. New treatment options using Tissue Engineering strategies for cartilage repair showed intriguing results. Human mesenchymal stem cells (MSC) isolated from bone marrow are becoming increasingly recognized for their potential to generate different cell types and thereby function effectively in vitro or in vivo in tissue repair. Incorporation of MSCs in suitable tissue engineering scaffolds and culture in chondrogenic medium can produce cartilage-like tissue. MSCs can be harvested from bone marrow by a small puncture of the iliac crest of patients. In contrast to chondral based repair this small procedure creates no additional harvest defect in the knee joints of the patient. Numerous publications show the beneficial influence of mechanobiological conditioning (e.g. mechanical compression, hydrostatic pressure, osmotic, shear, ultrasound) on the chondrogenic differentiation of dedifferentiated chondrocytes. In contrast to chondrocytes and cartilage explants there are few studies that examine the influence of mechanobiological stress on mesenchymal progenitor cells undergoing chondrogenesis. Using an in vitro aggregate culture system enhanced chondrogenesis of mesenchymal progenitor cells, detected by an increased extracellular matrix deposition of collagen and aggrecan, could be shown under repeated cyclic hydrostatic pressure. Similar results, with an increase in chondrogenic differentiation of mesenchymal progenitor cells could be detected, when the cells were loaded in three-dimensional matrices and subjected to cyclic, compressive load or low-intensity pulsed ultrasound. This review will summarize the current state of knowledge in the field of mechanobiological conditioning of mesenchymal stem cells and its possible clinical application. [ABSTRACT FROM AUTHOR]

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The localization of the neural cell adhesion molecule L1 in the male urogenital tract (including seminal vesicles and prostate) of the mouse and bull was investigated using immunocytochemical and immunochemical methods in order to better understand the function of this glycoprotein in non-neural tissues. L1 antibodies labeled non-myelinated nerves in all portions of the urogenital tract investigated. However, L1 immunoreactivity was also found between epithelial cells of several regions of the urogenital system including epididymal tail, deferent duct, ejaculatory duct and seminal vesicles. Some L1 immunoreactivity was also demonstrated between epithelial cells of murine urinary bladder and urethra. The specificity of the immunoreaction was verified by western blots. There was no correlation between L1 expression and proliferating activity as revealed by double immunocytochemistry using various markers of cell proliferation. This unexpected expression of L1 in nonneural tissue is mainly restricted to non-proliferating epithelia of those portions of the urogenital tract that are derived from the Wolffian duct. It is suggested that L1 in these epithelia could enhance the mechanical resistance and reduce transepithelial permeability. [ABSTRACT FROM AUTHOR]

Copyright of Langenbecks Archiv fuer Chirurgie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Microangiographic investigation of the glenoid labrum of the dog shows a rich vascular supply to the labrum except for its free edge. The vessels originate predominantly from the shoulder joint capsule and periosteum of the scapula neck. Several anastomoses to the glenoid vessels were demonstrated. This rich vascularization provides a good environment for surgical repair of traumatically detached parts of the labrum. [ABSTRACT FROM AUTHOR]

Copyright of Langenbeck's Archives of Surgery is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Langenbecks Archiv fuer Chirurgie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Langenbecks Archiv fuer Chirurgie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Langenbeck's Archives of Surgery is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)