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Background: Tissue engineering has the potential to repair cartilage structures in middle-aged and elderly patients using their own "aged" cartilage tissue as a source of reparative chondrocytes. However, most studies on tissue-engineered cartilage have used chondrocytes from postfetal or very young donors. The authors hypothesized that articular chondrocytes isolated from old animals could produce neocartilage in vivo as well as articular chondrocytes from young donors., Methods: Articular chondrocytes from 8-year-old sheep (old donors) and 3- to 6-month-old sheep (young donors) were isolated. Cells were mixed in fibrin gel polymer at 40 x 10 cells/ml until polymerization. Cell-polymer constructs were implanted into the subcutaneous tissue of nude mice and harvested at 7 and 12 weeks., Results: Samples and native articular cartilage controls were examined histologically and assessed biochemically for total DNA, glycosaminoglycan, and hydroxyproline content. Histological analysis showed that samples made with chondrocytes from old donors accumulated basophilic extracellular matrix and sulfated glycosaminoglycans around the cells in a manner similar to that seen in samples made with chondrocytes from young donors at 7 and 12 weeks. Biochemical analysis revealed that DNA, glycosaminoglycan, and hydroxyproline content increased in chondrocytes from old donors over time in a pattern similar to that seen with chondrocytes from young donors., Conclusions: This study demonstrates that chondrocytes from old donors can be rejuvenated and can produce neocartilage just as chondrocytes from young donors do when encapsulated in fibrin gel polymer in vivo. This study suggests that middle-aged and elderly patients could benefit from cartilage tissue-engineering repair using their own "aged" articular cartilage as a source of reparative chondrocytes.

Trabecular bone is a material of choice for reconstruction after trauma and tumor resection and for correction of congenital defects. Autologous bone grafts are available in limited shapes and sizes; significant donor site morbidity is another major disadvantage to this approach. To overcome these limitations, we used a tissue engineering approach to create bone replacements in vitro, combining bone-marrow-derived differentiated mesenchymal stem cells (MSCs) suspended in hydrogels and 3-dimensionally printed (3DP) porous scaffolds made of beta-tricalcium-phosphate (beta-TCP). The scaffolds provided support for the formation of bone tissue in collagen I, fibrin, alginate, and pluronic F127 hydrogels during culturing in oscillating and rotating dynamic conditions. Histological evaluation including toluidine blue, alkaline phosphatase, and von Kossa staining was done at 1, 2, 4, and 6 weeks. Radiographic evaluation and high-resolution volumetric CT (VCT) scanning, expression of bone-specific genes and biomechanical compression testing were performed at 6 weeks. Both culture conditions resulted in similar bone tissue formation. Histologically collagen I and fibrin hydrogels specimens had superior bone tissue, although radiopacities were detected only in collagen I samples. VCT scan revealed density values in all but the Pluronic F127 samples, with Houndsfield unit values comparable to native bone in collagen I and fibrin glue samples. Expression of bone-specific genes was significantly higher in the collagen I samples. Pluronic F127 hydrogel did not support formation of bone tissue. All samples cultured in dynamic oscillating conditions had slightly higher mechanical strength than under rotating conditions. Bone tissue can be successfully formed in vitro using constructs comprised of collagen I hydrogel, MSCs, and porous beta-TCP scaffolds.

Articular chondrocytes can synthesize new cartilaginous matrix in vivo that forms functional bonds with native cartilage. Other sources of chondrocytes may have a similar ability to form new cartilage with healing capacity. This study evaluates the ability of various chondrocyte sources to produce new cartilaginous matrix in vivo and to form functional bonds with native cartilage. Disks of articular cartilage and articular, auricular, and costal chondrocytes were harvested from swine. Articular, auricular, or costal chondrocytes suspended in fibrin glue (experimental), or fibrin glue alone (control), were placed between disks of articular cartilage, forming trilayer constructs, and implanted subcutaneously into nude mice for 6 and 12 weeks. Specimens were evaluated for neocartilage production and integration into native cartilage with histological and biomechanical analysis. New matrix was formed in all experimental samples, consisting mostly of neocartilage integrating with the cartilage disks. Control samples developed fibrous tissue without evidence of neocartilage. Ultimate tensile strength values for experimental samples were significantly increased (p < 0.05) from 6 to 12 weeks, and at 12 weeks they were significantly greater (p < 0.05) than those of controls. We conclude that articular, auricular, and costal chondrocytes have a similar ability to produce new cartilaginous matrix in vivo that forms mechanically functional bonds with native cartilage.

Severe crush injuries with avulsion require specific treatment strategies. Usually we find complete loss of soft tissue, nerves and vessels, where only tendons and parts of the phalanges are preserved. Primary reconstructive procedures are usually not possible due to the complexity of the injury with severely destroyed structures. Bone shortening should be avoided in order to maintain finger length and motion. Therefore, emergency soft-tissue coverage represents the first step. Later, sensibility and mechanical stability of the skin should be restored. In our clinic, seven patients with this injury pattern were treated. Three cases involved four finger crush-avulsion injuries. In all cases, we performed a primary soft-tissue coverage with a pedicled flap. In a second session, the skin areas of the first web space of both feet were transplanted as neurovascular flaps. With this strategy, a useful hand function could be restored. The functional results are described and advantages and disadvantages of various techniques discussed.

In a cross-sectional study dating from april 94 to march 96 we have investigated length and weight of 2610 girls and 2865 boys (age 4-18 years) at nursery schools and schools in Saarland. Thus we could provide first normative data for this region of Germany. Compared with data that have been collected between 1968 and 1989 at Dortmund, Bonn, Hamm and Jena, we found an increase in height of 2 cm for girls and boys aged 15-18 years. Apart from this finding, no further differences have been observed. Compared with international data, 18-year-old females and males in Saarland show large body heights: their average heights were 169 and 182 cm, respectively. Unfortunately, body weight of children of the Saarland is high, too. Children in Saarland were on average 1.5-6.6 kg heavier than those of the Dortmund study or other international studies. Studies have revealed that, according to the ECOG criteria, people of the Saarland are more obese than in other European countries. As a consequence of our study we request an institution for auxology to be founded which enables immediate reaction. This not only implies medical view points but also practical aspects of daily life (e.g. height of chairs or tables at schools). It is important to note that no changes have been made so far. Standards for height and weight should be updated every ten years. This should be a collaborative task between public health services and pediatric endocrinologists.

This study aimed to set up current reference charts of anthropometric data in the Saarland. Only national and international data were available to be compared but no former Saarland charts could be found. In the period between 1994 and 1995 we investigated children of 3 to 11 years in a cross-sectional study. Therefore we measured body height, weight, circumferences, skinfolds and bioelectrical impedance (BIA). No significant gender differences were found for body height and weight. Boys of all groups of age showed bigger abdominal circumferences than girls of the same age. On the other hand upper-arm and calf-girth of younger girls were larger than that from boys. In higher age groups circumferences become rather equal. The skinfolds of Saarland girls are thicker than those of boys. The urban rural comparison indicated no significant differences. Nor was any social divergence found among the aforementioned parameters. Regarding height Saarland children are seen to be similar or somewhat shorter than those examined in national or international studies. By the way, in higher percentiles the children in our study were heavier. Thus high BMI values of our study are bigger compared with former studies. According to the definition of obesity by the ECOG almost 20 to 30% of our children are obese. The older children become the higher is the percentage of obesity. Comparing girls and boys, bioelectrical impedance shows higher values for girls. In higher age classes resistance levels gets smaller, in boys more so than in girls. Body fat estimated by a formula based on BIA test parameters yielded negative values. So we propose the use of sex- and age-specific raw charts of BIA test parameters.