Das Recht des Staates zur postmortalen Organentnahme

Ohne Zusammenfassung     

Perforated colorectal neoplasms: correlation of clinical, contrast enema, and CT examinations

Results of clinical, contrast enema (CE), and computed tomographic (CT) examinations in 39 patients with perforated colorectal neoplasms were retrospectively reviewed. Twenty patients were toxemic at initial presentation, but in only four patients was the diagnosis of perforated colorectal neoplasm initially suspected clinically. CE study was performed in 22 patients and enabled the diagnosis of perforated neoplasm in 11 cases, neoplasm alone in eight, and neither neoplasm nor perforation in three. CT was performed in 38 patients and enabled the diagnosis of perforated neoplasm in 36; pericolic phlegmon but no mass lesion was evident in two. In 16 patients, CT also demonstrated metastatic disease. Because of its reliability in establishing the diagnosis and staging the extent of the inflammatory and neoplastic disease, CT is indicated in cases of suspected or proved perforated colorectal neoplasm and in cases in which CE study findings are indeterminate or suggestive of perforated neoplasm.     

Zur Lehre von den Zwangsvorstellungen

Ohne Zusammenfassung     

Frequent ongoing T-cell receptor rearrangements in childhood B- precursor acute lymphoblastic leukemia: implications for monitoring minimal residual disease

Crosslineage T-cell receptor delta (TCR delta) rearrangements are widely used as tumor markers for the follow up of minimal residual disease in childhood B-precursor acute lymphoblastic leukemia (ALL) by polymerase chain reaction (PCR). The major drawback of this approach is the risk of false-negative results due to clonal evolution. We investigated the stability of V delta 2D delta 3 rearrangements in a group of 56 childhood B-precursor ALL patients by PCR and Southern blot analysis. At the PCR level, V delta 2D delta 3-to-J alpha rearranged subclones (one pathway for secondary TCR delta recombination) were demonstrated in 85.2% of V delta 2D delta 3-positive patients tested, which showed that small subclones are present in the large majority of patients despite apparently monoclonal TCR delta Southern blot patterns. Sequence analysis of V delta 2D delta 3J alpha rearrangements showed a biased J alpha gene usage, with HAPO5 and J alpha F in 26 of 32 and 6 of 32 clones, respectively. Comparison of V delta 2D delta 3 rearrangement status between diagnosis and first relapse showed differences in seven of eight patients studied. In contrast, from first relapse onward, no clonal changes were observed in six patients studied. To investigate the occurrence of crosslineage TCR delta rearrangements in normal B and T cells, fluorescence-activated cell sorter-sorted peripheral blood CD19+/CD3- and CD19-/CD3+ cell populations from three healthy donors were analyzed. V delta 2D delta 3 rearrangements were detected at low frequencies in both B and T cells, which suggests that V delta 2-to-D delta 3 joining also occurs during normal B-cell differentiation. A model for crosslineage TCR delta rearrangements in B-precursor ALL is deduced that explains the observed clonal changes between diagnosis and relapse and is compatible with multistep leukemogenesis of B-precursor ALL.     

Identification of endothelial and mesothelial cells in human omental tissue and in omentum-derived cultured cells by specific cell markers.

Human omental tissue has been used as a source for the isolation and cultivation of microvascular endothelial cells, but also for mesothelial cells. Since both cell types have several morphologic and functional features in common, concerns were raised whether endothelial cells can be separated from mesothelial cells by the methods described for the isolation of microvascular endothelial cells. In the present study, endothelial cells were identified in the capillaries of native human omentum by several endothelial-cell specific markers. von Willebrand factor was demonstrated by polyclonal and monoclonal antibodies, a lectin-specific ligand by Ulex europaeus I, and an endothelial-cell specific surface epitope by the monoclonal antibody, PAL-E. These markers were not found positive with mesothelial cells of native omentum. Mesothelial cells were identified by monoclonal antibodies against the intermediate filaments, cytokeratin and vimentin. After having demonstrated the specificity of the methods for the distinction between endothelial and mesothelial cells within native omentum, these methods were applied to omentum-derived cells previously claimed to be microvascular endothelial cells. These cultured cells proved to be negative for von Willebrand factor, Ulex europaeus I ligand and PAL-E epitope. In contrast to this, the cultivated cells stained positive to cytokeratin and vimentin. Furthermore, it was shown by immunoprecipitation studies that omentum-derived cells did not synthesize and secrete vWF, indicating the nonendothelial nature of these cells. Finally, electron microscopy demonstrated microvilli on the surface of cultivated omentum-derived cells indicative for the mesothelial origin of these cells. The data presented demonstrate that the cells obtained using the previously published methods for the isolation and cultivation of "microvascular endothelial cells" from omental tissue are of mesothelial and not of endothelial origin. Thus, a great number of data obtained with this type of omentum-derived cells thought to be microvascular endothelial cells need re-evaluation.     

White Matter Fiber Tracking Computation Based on Diffusion Tensor Imaging for Clinical Applications

Fiber tracking allows the in vivo reconstruction of human brain white matter fiber trajectories based on magnetic resonance diffusion tensor imaging (MR-DTI), but its application in the clinical routine is still in its infancy. In this study, we present a new software for fiber tracking, developed on top of a general-purpose DICOM (digital imaging and communications in medicine) framework, which can be easily integrated into existing picture archiving and communication system (PACS) of radiological institutions. Images combining anatomical information and the localization of different fiber tract trajectories can be encoded and exported in DICOM and Analyze formats, which are valuable resources in the clinical applications of this method. Fiber tracking was implemented based on existing line propagation algorithms, but it includes a heuristic for fiber crossings in the case of disk-shaped diffusion tensors. We successfully performed fiber tracking on MR-DTI data sets from 26 patients with different types of brain lesions affecting the corticospinal tracts. In all cases, the trajectories of the central spinal tract (pyramidal tract) were reconstructed and could be applied at the planning phase of the surgery as well as in intraoperative neuronavigation.