Gunther O. Hofmann

Assessment of oxygen radicals during kidney transplantation — effect of radical scavenger

Abstract  In the present study, levels of free oxygen radicals, generated in the very early period of re‐perfusion during human kidney transplantation, were assessed by determination of malondialdehyde (MDA) levels using a high‐pressure liquid chromatography (HPLC) method. Renal blood samples were obtained during reperfusion by in‐traoperative cannulation of the renal vein. Simultaneously, systemic MDA levels were determined. Furthermore, local and systemic levels of interleukin 6 (IL‐6), tumor necrosis factor (TNF) receptors, p55 and p75, and vitamin E were measured. In a second group of patients, 500 mg of ascorbic acid were given prior to reperfusion. Renal MDA levels in the control group were always higher compared to systemic levels. IL‐6 showed a marked increase shortly after reperfusion in the renal blood. In the scavenger group there was a diminution of these effects. TNF receptor levels and vitamin E remained largely unchanged. The results of this pilot study demonstrated clinically the moderate production of reactive oxygen species and the liberation of IL‐6 shortly after reperfusion of human transplanted kidneys. Furthermore, the modulating effect of a radical scavenger on these effects was shown.

Early infiltration of renal allografts with 27E10-positive macrophages and graft outcome

Abstract Recently, we have demonstrated that acute cellular rejection is correlated with a massive infiltration of 27E10‐positive macrophages. To examine the distribution of macrophage differentiation markers in the infiltrate in the very early post‐transplantation period, two biopsies were taken intraoperatively, approximately 3 h following reperfusion, in each of 16 renal transplant recipients. One biopsy was taken for conventional histology and the other biopsy was snap‐frozen. The sections were stained using an ABC indirect immunoperoxidase technique. A panel of monoclonal antibodies against three macrophage differentiation markers (27E10, 25 F 9 and RM3/1) was used to stain the sections. Using the early inflammation macrophage marker 27E10, there was an unexpected strong staining in 3 out of 16 biopsies. This severe infiltration of 27E10‐positive macrophages with 10–20 macrophages per high power field (compared to 0–2 in others) was correlated in all cases with a poor outcome of the graft. All seven kidneys with no 27E10‐positive infiltration showed a good function 6 weeks post‐transplantation. The other macrophage markers, 25 F 9 and RM3/1, showed a less marked correlation with graft outcome. In conclusion, a massive infiltration of renal allografts with 27E10‐positive macrophages 1 h post‐transplantation may be a very early predictor of poor graft outcome.

Positive donor and negative recipient cytomegalovirus status is a detrimental factor for long‐term renal allograft survival

Abstract In 524 allogeneic cadaveric kidney transplants, the impact of cytomegalovirus (CMV) donor/recipient status on the incidence of CMV infection, CMV disease, early and long‐term graft, and patient survival have been analyzed with respect to rejection episodes. Most CMV infections (59%) and diseases (17%) were found in CMV‐negative recipients of CMV‐positive kidneys. The 1‐year function rate of CMV‐positive kidneys (75%) dropped about 10% below that of CMV‐negative organs (85%), and in the case of CMV‐negative recipients an additional graft loss of more than 10% happened within the 4th and 5th years (5‐year graft survival pos./neg.: 56%). This detrimental effect was exaggerated if it coincided with antibody‐treated rejection episodes.

Biomechanical investigation of uniplanar and biplanar cuts in openingwedge high tibial osteotomy

This study was aimed to determine the biomechanical properties of uniplanar tranversial (UPO) and biplanar, three-dimensional (BPO) osteotomy in medial opening wedge high tibial osteotomy (HTO) in a comparable Sawbone model. Third generation tibial Sawbones were osteotomized in a standardized manner and fixed with an angle-stable, spacer containing plate. Axial stiffness after one and twenty loading cycles (range 50 to 1000 N) was registered as well as displacement within the osteotomy gap and load at failure. After one loading cycle no differences between BPO (n=5) and UPO (n=5) specimens were evaluated. The undergoing of 20 loading cycles caused a significant loss of stiffness. After the cycles BPO specimen had a stiffness of 1755.9 ± 129.2 N/mm. The stiffness in UPO specimen was 1018.5 ± 15.5 N/mm. The difference between the groups was significant. The mean maximum load at failure in UPO specimens was 2633.1 ± 229.4 N. Specimens after BPO had a significant higher maximum load at failure of 4554.8 ± 342.8 N. In BPO specimens the failure always was caused by an infraction in the lateral cortex, whereas in UPO the failure was caused in two-times by an additional dorsal dislocation of the tibial head. This study was undertaken to evaluate the biomechanical properties of a UPO and BPO in medial wedge osteotomy. The results offer a significant advantage for the BPO regarding to axial stiffness under cyclic loading as well as resistance against load to failure. References [1] Bergenudd H,Sahlstrom A,Sanzen L. Total knee arthroplasty after failed proximal tibial valgus osteotomy. J Arthroplasty 1997; 12: 635-638. [2] Coventry MB. Osteotomy of the upper portion of the tibia for degenerative arthritis of the knee. J Bone Joint Surg Am 1965; 47: 984-990. [3] Insall JN,Joseph DM,Msika C. High tibial osteotomy for varus gonarthrosis. A long-term follow-up study. J Bone Joint Surg Am 1984; 66: 1040-1048. [4] Klinger HM,Lorenz F,Harer T. Open wedge tibial osteotomy by hemicallotasis for medial compartment osteoarthritis. Arch Orthop Trauma Surg 2001; 121: 245-247. [5] Koshino T,Murase T,Takagi T,Saito T. New bone formation around porous hydroxyapatite wedge implanted in opening wedge high tibial osteotomy in patients with osteoarthritis. ORIGINAL ARBEITEN Gunter Spahn: Biomechanical investigation of uniplanar cuts in opening-wedge high tibial osteotomy Width the dorsal osteotomy gap [mm] under a load of 1000 N After 1 cycle After 20 cycles

Die tibiotalare und tibiotalokalkaneare Marknagelarthrodese

Es sind vielfältige Osteosynthesetechniken für die tibiotalare und tibiotalokalkaneare Arthrodese (TTKA) beschrieben. Neben Schraubenwerden überwiegend Platten-, Fixateur externeund Marknageltechniken verwendet [7,8,33,36]. Die Kompression, die stabile Osteosynthese, die korrekte Achseinstellung des Rückfußes und die Aneinanderlagerung gut durchbluteter Knochenflächen werden als wesentliche Prinzipien angesehen [7,17,27,31]. Bereits Küntscher beschrieb 1962 die geschlossene retrograde TTKA mit konischem Marknagel ohne Verriegelung [19]. Mittlerweile liegen spezielle Marknägel mit angepassten Verriegelungsoptionen und mit optionalem Kompressionsmechanismus vor. Mann et al. wiesen eine signifikant verbesserte Rotationssteifigkeit für retrograde Marknägel mit einer Verriegelungsschraube entlang der Kalkaneuslängsachse verglichen mit einer konventionellen transversalen Verriegelungsschraube nach [22]. Berson et al. konnten die relevante Kompression der Gelenkflächen durch einen Marknagel mit Kompressionsmechanismus zeigen [5]. Es ist zu mutmaßen, dass die Kompression der Arthrodesenfläche durch einen Marknagel [2] wie auch die Kompression bei anderen Osteosynthesen in der Frakturund Pseudarthrosenbehandlung einen relevanten Einfluss Autoren: Thomas Mückley, Stefan Eichhorn , Erwin Steinhauser, Konrad Hoffmeier, Geert von Oldenburg, Claudia Beimel, Volker Bühren, Gunther O. Hofmann

Überbrückung langstreckiger Knochen- und Gelenkdefekte durch allogene vaskularisierte Transplantate

Three patients with large osseous defects following trauma and infection received vascularized allogeneic femoral diaphyses and five patients vascularized allogeneic total knee joints. From the surgical aspect these transplantations are technically feasible. The remaining problems are of immunological nature; at least in patients with allogeneic synovial joints, lifelong immunosuppression seems to be currently unavoidable.