346. Die bedeutung von stenosen an gefä\verzweigungen. eine experimentelle untersuchung an der femoralisgabel unter besonderer berücksichtigung der indikation zur profundaplastik

Zusammenfassung In einem pulsatil mit Kochsalz durchströmten Modell der Femoralisgabel wurden Flussmessungen und Druckgradienten für Flussmengen von 170 bis 860 ml/min bei peripheren Widerständen von 232 bis 25 792 dyn s cm^–5 über dem Superficialis- und Profundaabgang bei Stenosen von 1 cm Länge und Querschnittsverminderungen von 0% bis 100% gemessen. Bei grossen Flussmengen (800–860 ml/min) und kleinem peripheren Widerstand (<640 dyn s cm^–5) lag die kritische Stenose am Profundaabgang bei 4,1 mm Durchmesser, für hohe periphere Widerstände (> 5 072 dyn s cm^–5) bei 2,6 mm; bei kleinen Flussmengen (<400 ml/min) betrug der kritische Durchmesser 1,8 mm. Der nicht stenosierte Profundaabgang stellte für keine der Versuchsbedingungen ein strömungsdynamisches Hindernis dar.     

Fusion of bone marrow-derived stem cells with cardiomyocytes in a heterologous in vitro model.

OBJECTIVE: Recent studies have demonstrated that transplanted bone marrow-derived stem cells (BMCs) possess a broad differentiation potential and are able to form new cardiomyocytes. However, the identity of BMCs as true cardiomyocytes is still ambiguous. Therefore, we investigated the fate of transplanted fluorescence labeled BMCs and cardiomyocytes in co-culture. METHODS: For cell tracking we used two different fluorescent probes, Vybrant/DiO and Vybrant/DiI. BMCs were taken from human sternal marrow, purified using a Ficoll-gradient-centrifugation, treated with 5-azacytidine and stained with Vybrant/DiO. Furthermore, isolated spontaneous beating cardiomyocytes of neonatal rats (CM) were labeled with Vybrant/DiI. Thereafter, the BMCs were transplanted into CM-cultures and investigated on day 1, 4, 7, 14 and 28 using two-color fluorescence phenotyping by laser-scanning-cytometry (LSC). Two-color positive cells were harvested by patch-clamp technique and beta-MHC mRNA expression was analyzed by single-cell PCR. RESULTS: Two different morphological phenotypes were observed by LSC. First, isolated DiO labeled BMCs without contact or with direct cell contact to DiI labeled CMs. Second, some BMCs and CMs were double positive for DiO/DiI spontaneously forming hybrids. This population increased by 18% from day 1 to 4 and decreased only slightly until day 28. Additionally, few two-color positive cell formations expressed both human and rat specific beta-MHC mRNA as well as only human beta-MHC mRNA indicating that cell-fusion and transdifferentiation has occurred. CONCLUSION: These observations provide in vitro evidence for spontaneous cell fusion and transdifferentiation of BMCs in co-culture, raising the possibility that the observed phenomenons may contribute to development or maintenance of these cell types.     

Veränderungen des operativen Krankenguts

Die Anaesthesiologie - Die Veränderung der Altersstruktur der Bevölkerung der Industrieländer führte zu einer Verschiebung der zu behandelnden (Alters-)Erkrankungen gleichzeitig...     

A new bioassay including a small scale hepatocyte bioreactor for hepato-mediated toxicity testing in a target cell line

New approaches for in vitro testing of hepato-mediated toxicity are undertaken to offer alternatives to in vivo animal testing. The described bioassay for hepato-mediated toxicity testing is based on a small scale hepatocyte-bioreactor with pig hepatocytes connected to a silicon sensor based microphysiometer system for monitoring of the extracellular acidification rate (EAR) of cells and the microphysiometer alone. EAR represents the metabolic activity of tested cells (hepatocytes and ZR 751 cells) under the influence of perfused media, compared to controls, which were set to 100%. Cyclophosphamide (CYCL), whose cytostatic effect is dependent on CYP 450 biotransformation was used as a model substrate. CYCL showed decrease of EAR in hepatocytes, but not in ZR 751 cells. Bioreactor supernatant including CYCL was pumped into the microphysiometer and EARs of the target ZR 751 cell line were recorded. After 7 h of bioreactor supernatant perfusion the ZR 751 cell line showed an EAR decrease of 18.68% +/- 10.18, as compared to controls (bioreactor supernatant from the identical set-up without CYCL). Thus the presented model of hepato-activated toxicity showed an EAR decrease in the ZR 751 cell line that reflected the toxic activation of CYCL by the bioreactor. This new bioassay serves as an example of future applications for hepatocyte bioreactors in automated toxicity testing devices, e.g. in preclinical drug studies or evaluation of hepato-mediated toxicity, not depending on cell destruction or further assays.     

DNA in human glioblastomas. A flow-fluorescence cytometrical examination of 96 tumors

The Flow-Fluorescence Cytometric Method (FCM) was applied to investigate the DNA content and the ploidy outlines of each of 96 glioblastomas. No specific DNA pattern was detected, possibly because of the tangle morphology of these variable tumors. Due to their capricious growth the DNA distribution proved to fluctuate greatly. Thus, the series, arranged according to increased PI (proliferation index) values, exhibited a wide spread within a total range from 7.1–97.15% (mean 39.3%) PI. A threefold subdivision of main types (I–III) appears to be of practical use for clinical prognostic assessment: diploid tumors with a PI range up to 10% (N=7) are followed by abnormal chiefly tretra- and hyper-tetraploid tumors up to PI values about 30% (N=21). The third category includes cases showing excessive aneuploidy combined more and more with polyploidy and valid stemlines, up to the PI maximum of about 97 rel.% (N=68). Thus, in 89 tumors clear pathological changes of DNA content can be decoded; of these 68 (76.4%) express a considerable aneuploidy and polyploidy respectively.Dedicated to Prof. Dr. HJ Bauer for his 75th birthday, March 31, 1989     

Pulmonary graft function after long-term preservation of non-heart-beating donor lungs

BACKGROUND: Critical organ shortage in lung transplantation could be attenuated by the use of non-heart-beating donor (NHBD) lungs. In addition, prolonged ischemic tolerance of the organs would contribute to the alleviation of organ shortage. The aim of this study was to investigate pulmonary graft function of NHBD lungs after long-term hypothermic storage. METHODS: Twelve native-bred pigs (bodyweight 20 to 30 kg) underwent left lung allotransplantation. In the heart-beating donor (HBD) group, lungs were harvested immediately after cardiac arrest. In the NHBD group, lungs were subjected to a warm ischemic period of 90 minutes before harvesting. After a total ischemic time of 19 hours, pulmonary grafts in both groups were reperfused and pulmonary graft function was assessed. All values were compared with a sham-operated control group. RESULTS: Pulmonary graft function in the HBD group was excellent. In the NHBD group, pulmonary gas exchange was impaired, but still provided good graft function compared with the excellent graft function in the HBD group. Pulmonary vascular resistance was even lower in the NHBD group. In the NHBD group, calculated intrapulmonary shunt fraction (Qs/Qt) was significantly increased compared with the sham-group. Histologic alteration and wet-to-dry ratio did not differ significantly between the HBD and NHBD group. CONCLUSIONS: We conclude that NHBD lungs (90 minutes of warm ischemic time) have the potential to alleviate organ shortage in lung transplantation even after an extended total ischemic time.     

Extended stereotactic brain biopsy in suspected primary central nervous system angiitis: good diagnostic accuracy and high safety

Journal of Neurology - To evaluate the diagnostic accuracy and safety of extended stereotactic brain biopsy (ESBB) in a single center cohort with suspected primary angiitis of the central nervous...     

Characterization of synovial fluid from periprosthetic infection in revision total joint arthroplasty by single-molecule microscopy

Periprosthetic joint infection is among the most common and severe complications in total joint arthroplasty. Today, a combination of different methods is used for diagnosis because no single method with sufficient sensitivity and specificity is available. In this study, we explored the usability of single-molecule microscopy to characterize synovial fluid samples from periprosthetic joint infections. Patients (n = 27) that needed revision arthroplasty underwent the routine diagnostic procedures for periprosthetic joint infection of the University Hospital in Bonn. Additionally, the diffusion rate of two probes, dextran and hyaluronan, was measured in small volumes of periprosthetic synovial fluid samples using single-molecule microscopy. To evaluate the suitability of single-molecule microscopy to detect PJI the AUC for both markers was calculated. The diffusion rate of hyaluronan in periprosthetic synovial fluid from patients with septic loosening was faster than in samples from patients with aseptic loosening. Single-molecule microscopy showed excellent diagnostic performance, with an area under the receiver operating characteristic curve of 0.93, and allowed the detection of periprosthetic joint infection in patients that would be challenging to diagnose with current methods. For the first time, single-molecule microscopy was used to detect periprosthetic joint infection. Our results are encouraging to study the value of single-molecule microscopy in a larger patient cohort. The speed and accuracy of single-molecule microscopy can be used to further characterize synovial fluid, potentially allowing intraoperative diagnosis of periprosthetic joint infections in the future.