Detection algorithm for the validation of human cell lines.

Cell lines are an important tool in understanding all aspects of cancer growth, development, metastasis and tumor cell death. There has been a dramatic increase in the number of cell lines and diversity of the cancers they represent; however, misidentification and cross-contamination of cell lines can lead to erroneous conclusions. One method that has gained favor for authenticating cell lines is the use of short tandem repeats (STR) to generate a unique DNA profile. The challenge in validating cell lines is the requirement to compare the large number of existing STR profiles against cell lines of interest, particularly when considering that the profiles of many cell lines have drifted over time and original samples are not available. We report here methods that analyze the variations and the proportional changes extracted from tetra-nucleotide repeat regions in the STR analysis. This technique allows a paired match between a target cell line and a reference database of cell lines to find cell lines that match within a user designated percentage cut-off quality matrix. Our method accounts for DNA instability and can suggest whether the target cell lines are misidentified or unstable.

Comparison of two different matrix-based autologous chondrocyte transplantation systems: 1 year follow-up results.

PURPOSE: The treatment of full-thickness cartilage defects of the knee is a common problem in orthopaedic surgery. Autologous chondrocyte transplantation (ACT) is one of the few reliable treatment options of cartilage defects with good long-term outcomes. The improvement of ACT led to the matrix-based ACT (MACT). The purpose of the study was to compare two different commercially available MACT systems. METHODS: Eleven patients with a cartilage defect of the knee were treated with the MACI(®) system and another nine patients with the CaRes(®) implant. The patients were prospectively followed and re-examined after one year. RESULTS: One year after surgery all but one patient have significantly improved in their clinical outcome. Both types of MACT revealed similar results in terms of increase in level of activity, pain relief and knee function. CONCLUSION: The study showed that MACT is a good therapeutic option for full-size defects of the femoral condyle. The MACI(®) implant seems to be easier to handle which is reflected by smaller incisions and a shorter operation time.

[Endosteal reaction in the region surrounding the stem of a cement-free prosthesis. An early radiological sign of imminent fracture of the femoral shaft?]. / Endostale Reaktion im Schaftbereich einer zementfreien Prothese. Ein radiologisches Frühzeichen einer drohenden Femurschaftfraktur?

Periprosthetic fractures are familiar complications after total hip arthroplasty and have often been reported in the literature. The most frequent localization of such fractures is the middle third of the shaft. In the case described here a minor trauma resulted in a periprosthetic fracture with fracture of the femur and of the femoral component of a Lord prosthesis. A radiograph taken prior to trauma showed an endosteal reaction at the level at which the fracture later occurred. This might have been an indication that the stem of the prosthesis was already broken; had this radiological sign been correctly interpreted, it is possible that the fracture could have been avoided.

Epidemiology of posterior cruciate ligament injuries.

BACKGROUND: The epidemiology of posterior cruciate ligament (PCL) injuries has not been well clarified. Isolated and combined PCL injuries are a frequently missed diagnosis. A better understanding of typical injury mechanisms may help in more accurate diagnosis of these injuries. METHODS: In this study the epidemiology of PCL insufficiency in 494 patients was retrospectively analysed. Stress-radiography was used to quantify posterior tibial displacement. RESULTS: The mean age at the time of injury was 27.5+/-9.9 years. Traffic accidents (45%) and athletic injuries (40%) were the most common injury causes. Motorcycle accidents (28%) and soccer-related injuries (25%) accounted for the main specific injury causes. The most common injury mechanisms were dashboard injuries (35%) and falls on the flexed knee with the foot in plantar flexion (24%). The mean side-to-side difference of posterior tibial displacement on posterior stress-radiographs in 90 degrees of flexion was 13.4+/-4.7 mm. According to the posterior displacement values, 232 (47%) patients had isolated PCL ruptures, while 262 (53%) patients with a posterior displacement of >12 mm were classified as having a combined posterior instability. There were significantly more combined PCL lesions due to vehicular trauma as compared with athletic trauma ( p<0.0001). CONCLUSIONS: In many PCL lesions, initiation of an adequate treatment regimen is delayed despite typical injury mechanisms and symptoms. In the future, a better understanding of the epidemiology of PCL injuries should enable us to diagnose the injury more reliably through a detailed history and a thorough physical and radiographic examination in the acute setting.

Determination of main and minor components of silicon based materials by a combustion with elemental fluorine. Separation of gaseous fluorination products by carrier gas distillation and gas mass spectrometry

For the determination of main and minor components in silicon-based ceramic powders, a decomposition by a combustion with elemental fluorine and separation of the volatile fluorination products by a carrier-gas distillation with a subsequent detection by quadrupole mass spectrometry is described. The necessity and success of the separation step is demonstrated for the determination of boron as a minor constituent in SiC, where the spectral interferences of silicon on the boron signals are decreased considerably. The method developed is shown to be directly applicable to determination of silicon in Si3N4, SiC, and SiO2. The determination of nitrogen in Si3N4 requires additional effort, to separate nitrogen from the excess of fluorine. For the determination of boron, a complete mobilization of BF3 is assured by the presence of an adequate amount of GeF4. Analysis results obtained with different types of calibration show a precision of 30 microg for boron at the milligram-per-gram level and a precision between 0.5 and 2% (m/m) for the main components, silicon and nitrogen. Within these standard deviations, the results agree well with the values expected from the stoichiometry, with the results for silicon and boron obtained by wet chemical decomposition and slurry techniques in combination with ICP-OES and with the results for nitrogen obtained by carrier gas heat extraction.