Manfred Köller

Publications of Manfred Köller

• Regenerate augmentation with bone marrow concentrate after traumatic bone loss.

  Authors: Jan Gessmann, Manfred Köller, Holger Godry, Thomas Armin Schildhauer, Dominik Seybold

  Orthopedic reviews. 01/2012; 4(1):e14.

  Distraction osteogenesis after post-traumatic segmental bone loss of the tibia is a complex and time-consuming procedure that is often complicated due to prolonged consolidation or completeDistraction osteogenesis after post-traumatic segmental bone loss of the tibia is a complex and time-consuming procedure that is often complicated due to prolonged consolidation or complete insufficiency of the regenerate. The aim of this feasibility study was to investigate the potential of bone marrow aspiration concentrate (BMAC) for percutaneous regenerate augmentation to accelerate bony consolidation of the regenerate. Eight patients (age 22-64) with an average posttraumatic bone defect of 82.4 mm and concomitant risk factors (nicotine abuse, soft-tissue defects, obesity and/or circulatory disorders) were treated with a modified Ilizarov external frame using an intramedullary cable transportation system. At the end of the distraction phase, each patient was treated with a percutaneously injection of autologous BMAC into the centre of the regenerate. The concentration factor was analysed using flow cytometry. The mean follow up after frame removal was 10 (4-15) months. With a mean healing index (HI) of 36.9 d/cm, bony consolidation of the regenerate was achieved in all eight cases. The mean concentration factor of the bone marrow aspirate was 4.6 (SD 1.23). No further operations concerning the regenerate were needed and no adverse effects were observed with the BMAC procedure. This procedure can be used for augmentation of the regenerate in cases of segmental bone transport. Further studies with a larger number of patients and control groups are needed to evaluate a possible higher success rate and accelerating effects on regenerate healing.

• Osteogenic differentiation of human mesenchymal stromal cells is promoted by a leukocytes containing fibrin matrix.

  Authors: Dominik Seybold, Thomas A Schildhauer, Jan Gessmann, Gert Muhr, Manfred Köller, Bernd Roetman

  Langenbeck's archives of surgery / Deutsche Gesellschaft für Chirurgie. 08/2010; 395(6):719-26.

  Mesenchymal stem cells (multipotent human mesenchymal stromal cells, MSC) are currently the most promising cell type for regenerative medicine. For a clinical approach, it is necessary to develop andMesenchymal stem cells (multipotent human mesenchymal stromal cells, MSC) are currently the most promising cell type for regenerative medicine. For a clinical approach, it is necessary to develop and establish methods for expansion, differentiation, and delivery. A completely autologous plasma clot containing peripheral blood mononuclear cells (PBMC) was tested for the osteopromotive activity towards expanded human mesenchymal stem cells in vitro. The plasma clot was prepared from anticoagulated blood plasma after addition of isolated leukocytes and calcium chloride. Plasma clots after the gelation were added to subconfluently growing MSC or used in a transwell system. Cell proliferation, the activity of alkaline phosphatase, the release of osteoprotegerin, C-terminal procollagen peptide, as well as osteocalcin, the analysis of matrix mineralization as well as bone nodule formation were analyzed up to 3 weeks. In contrast to plasma clots with no exogenously added leukocytes, the presence of PBMC within the plasma clot significantly promoted osteogenic differentiation of MSC correlated to the time period of incubation. Proliferation of MSC was decreased at maximal mineralization time points. In addition, the osteopromotive activity was identified as soluble factor/factors by transwell assay system. There was a decrease in osteoprotegerin when the cells were cultured in the presence of plasma clots compared to control cell cultures without plasma clots. The osteocalcin expression was continuously higher after culture in the presence of plasma clots and significantly higher after 2- and 3-week after culture in the presence of leukocyte-containing plasma clots compared to 1-week cell culture. Differences in the concentration of the C-terminal procollagen peptide were not measured. The direct inoculation of an autologous mononuclear cell fraction (which contains leukocytes and MSC), e.g., isolated from a bone marrow aspirate or a different source into an autologous plasma gel, may be a further new strategy for bone fracture therapy.

• Microvascular response to calcium phosphate bone substitutes: an intravital microscopy analysis.

  Authors: Bernd Roetman, Andrej Ring, Stefan Langer, Thomas A Schildhauer, Gert Muhr, Manfred Köller

  Langenbeck's archives of surgery / Deutsche Gesellschaft für Chirurgie. 03/2010; 395(8):1147-55.

  The purpose was to evaluate inflammatory and microcirculatory reactions after implantation of various calcium phosphate bone substitutes in an in vivo model. Calcium phosphate-based bone substitutesThe purpose was to evaluate inflammatory and microcirculatory reactions after implantation of various calcium phosphate bone substitutes in an in vivo model. Calcium phosphate-based bone substitutes were implanted in dorsal skinfold chambers of mice. Intravital fluorescence microscopy was performed to measure inflammatory and microcirculatory reactions based on functional vessel density (FVD), capillary leakage, and relative white blood cell velocity (rWBCV). An increase of FVD was observed in all groups and the capillary leakage grew with a level of significance (p < 0.001). The fraction of rolling and sticking leukocytes (rWBCV) was highest at the beginning of the trial and decreased during the course. There are differences in microvascular soft tissue reactions between various calcium phosphate bone substitutes, but inflammatory reactions were moderate, and the results revealed no reasons which explain the sporadic failure of the tested substances under clinical conditions.

• Generation of novel single-chain antibodies by phage-display technology to direct imaging agents highly selective to pancreatic {beta}- or {alpha}-cells in vivo.

  Authors: Sandra Ueberberg, Juris J Meier, Carmen Waengler, Wolfgang Schechinger, Johannes W Dietrich, Andrea Tannapfel, Inge Schmitz, Ralf Schirrmacher, Manfred Köller, Harald H Klein, Stephan Schneider

  Diabetes. 08/2009;

  Objective: Non-invasive determination of pancreatic beta-cell mass in vivo has been hampered by the lack of suitable beta-cell specific imaging agents. This report outlines an approach for theObjective: Non-invasive determination of pancreatic beta-cell mass in vivo has been hampered by the lack of suitable beta-cell specific imaging agents. This report outlines an approach for the development of novel ligands homing selectively to islet-cells in vivo. Research Design and Methods: In order to generate agents specifically binding to pancreatic islets, a phage-library was screened for single-chain-antibodies (SCAs) on rat islets using two different approaches: (1) The library was injected into rats in vivo, and islets were isolated after a circulation time of 5 minutes. (2) Pancreatic islets were directly isolated, and the library was panned in the islets in vitro. Subsequently, the identified SCAs were extensively characterized in vitro and in vivo. Results: We report the generation of SCAs that bind highly selective to either beta- or alpha-cells. These SCAs are internalised by target cells, disappear rapidly from the vasculature and exert no toxicity in vivo. Specific binding to beta- or alpha-cells was detected in cell-lines in vitro, in rats in vivo, and in human tissue in situ. Electron microscopy demonstrated binding of SCAs to the endoplasmatic reticulum and the secretory granules. Finally, in a biodistribution study the labeling intensity derived from [(125)I]-labeled SCAs after i.v. administration in rats strongly predicted the beta-cell mass and was inversely related to the glucose excursions during an intraperitoneal glucose tolerance test. Conclusions: Our data provide strong evidence that the presented SCAs are highly specific for pancreatic beta-cells and enable imaging and quantification in vivo.

• [In Process Citation]

  Authors: Jörg Hauser, Christopher D Krüger, Helmut Halfmann, Peter Awakowicz, Manfred Köller, Stefan A Esenwein

  Biomedizinische Technik. Biomedical engineering. 02/2009; 54(2):98-106.

  Abstract Background: Plasma treatment leads to a significant change of surface free energy of medical implant materials. These changes strongly influence protein and cell adhesion on the materialAbstract Background: Plasma treatment leads to a significant change of surface free energy of medical implant materials. These changes strongly influence protein and cell adhesion on the material surface. The aim of the study was to quantify the plasma-induced surface changes and to analyse whether the change of treatment parameters, such as pressure, gas mixture, energy and treatment time, influences the surface free energy of the implant materials. To improve the biocompatibility of the surfaces, polyamino acid coating experiments were performed. Materials and methods: Three different metal implant materials (X2CrNiMo18-15-3, Ti6Al4V, Ti6Al7Nb) were treated with a double-inductively coupled low-pressure plasma. The influence of treatment parameter variation on the surface free energy was evaluated by drop shape analysis. The plasma treated and non-treated materials were incubated in collagen I solution. Afterwards, the coatings were analysed by electron microscopy in terms of structure and adhesion. Results: Drop shape analysis revealed that plasma treatment leads to a significant increase of surface free energy in all groups. Long plasma treatment times and low treatment pressures lead to a significant (p<0.05) extension of the detectable surface free energy increase. Coating experiments showed that only on plasma-treated samples solid and adherent collagen layers could be achieved.

• Elevated Systemic Interleukin-18 in Multiple Injured Patients Is Not Related to Clinical Outcome.

  Authors: Bernd Roetman, Christian Schinkel, Mark Wick, Thomas Frangen, Gert Muhr, Manfred Köller

  Journal of interferon & cytokine research : the official journal of the International Society for Interferon and Cytokine Research. 10/2008;

  Interleukin-18 (IL-18) is a pleiotropic proinflammatory cytokine with the ability to induce interferon-gamma production in T-helper cells type 1 and natural killer cells. To investigate the role ofInterleukin-18 (IL-18) is a pleiotropic proinflammatory cytokine with the ability to induce interferon-gamma production in T-helper cells type 1 and natural killer cells. To investigate the role of IL-18 after severe trauma we measured plasma levels of IL-18 in 229 multiple injured patients [mean age of 39 +/- 16 (range 11-81) years, injury severity score (ISS) of 31 +/- 10 (range 16-66) points; 55 women and 174 men] and correlated these with demographics, clinical course, and routine laboratory parameters. IL-18 plasma levels were significantly increased in polytraumatized patients compared to healthy donors (p < 0.001). Survivors presented significantly (p < 0.05) higher IL-18 plasma median values (n = 193, median 98 pg/mL) compared to nonsurvivors (n = 36, median 63 pg/mL). Patients >60 years old (n = 35) had significantly lower plasma levels of IL-18 (median 45 pg/mL) compared to younger ones (n = 194, median 92 pg/mL). In the subgroup of nonsurvivors (n = 12) elderly patients had the lowest plasma levels of IL-18 (median 45 pg/mL). Patients with an ISS >25 had significant higher IL-18 plasma levels compared to the group with an ISS </=25 (p < 0.001). Our data demonstrate elevated plasma levels of IL-18 after severe trauma.

• [A double inductively coupled low-pressure plasma for sterilization of medical implant materials].

  Authors: Jörg Hauser, Helmut Halfmann, Peter Awakowicz, Manfred Köller, Stefan A Esenwein

  Biomedizinische Technik. Biomedical engineering. 08/2008; 53(4):199-203.

  The potential of plasma treatment in medicine is only slowly gaining acceptance. Inactivation of germs through exposure to UV radiation produced by plasma discharges and sterilization of medicalThe potential of plasma treatment in medicine is only slowly gaining acceptance. Inactivation of germs through exposure to UV radiation produced by plasma discharges and sterilization of medical implant devices and instruments is one possible application of this technique. In addition, due to the manifold possibilities of coating through plasma processes, quick sterilization-coating combinations of medical implant devices are possible. To analyze the effectiveness of this sterilization process on different material surfaces, three different alloys (X2CrNiMo18-15-3, Ti6Al7Nb and Ti6Al4V) and one thermoplastic material (ultra-high molecular weight polyethylene, UHMWPE), commonly used in medical implant devices, were examined in the presented study. After spraying Bacillus atrophaeus spores (10(6) CFU) on the surfaces of four different implant materials tested in this study (X2CrNiMo18-15-3, UHMWPE, Ti6Al7Nb and Ti6Al4V), it was demonstrated in each of four gas mixtures used (Ar, Ar:O2, Ar:H2 and Ar:N2) that due to the application of inductively coupled low-pressure plasma technique, plain medical implant materials can be sterilized rapidly, and can be protective and efficient.

• Systemic IL-17 after severe injuries.

  Authors: Thomas M Frangen, Denise Bogdanski, Christian Schinkel, Bernd Roetman, Thomas Kälicke, Gert Muhr, Manfred Köller

  Shock (Augusta, Ga.). 05/2008; 29(4):462-7.

  IL-17 is a cytokine produced by a newly identified T-cell subpopulation (THl7/THIL-17). It is a central mediator in inflammatory processes that connects T-cell stimulation with neutrophilIL-17 is a cytokine produced by a newly identified T-cell subpopulation (THl7/THIL-17). It is a central mediator in inflammatory processes that connects T-cell stimulation with neutrophil mobilization. The role of IL-17 in the immune dysfunction after polytrauma is still not clarified. In a retrospective study, the systemic concentration of IL-17 and IL-6 of 71 polytraumatized patients were analyzed daily by enzyme-linked immunosorbent assay. The patients' collective consist of 55 men and 16 women (43 +/- 16 years; injury severity score, 33 +/- 13). In only 6% of the patients, an increase in systemic IL-17 was detected. In most patients (94%), no systemic IL-17 was detectable or the IL-17 concentrations in plasma were in the range of the healthy donor group. To identify a possible role of systemic IL-17 in the posttraumatic phase, the patients were divided into two groups. Group A (47 men, 15 women) consists of patients with IL-17 concentrations in the range of normal healthy donors. Group B (8 men, 1 woman) consists of patients with elevated (>45 pg ml(-1) on at least 3 consecutive days) systemic IL-17 concentrations. Three patients in group B showed highly increased systemic IL-17 concentrations (median, >200 pg mL(-1)). These patients were male and showed all blunt chest and abdominal trauma with lung contusion and pneumohemothorax. However, there was no conformity in other injury patterns, injury severity score, age, outcome, intensive care period, or clinical complications. After a period of 4 years, we were able to obtain a new blood sample from one patient with high IL-17 level. The systemic IL-17 value of this former patient was now less than the detection limit. However, stimulation of peripheral blood mononuclear cells from thlise patient revealed elevated numbers of cells with the capacity to produce IL-17 as determined by enzyme-linked immuno spot assay and flow cytometry compared with peripheral blood mononuclear cells obtained from current polytrauma patients and healthy donors. In conclusion, IL-17 is not suitable as a pathophysiological or predictive marker after polytrauma. Whether highly increased systemic IL-17 concentrations detected in single patients are due to individually increased numbers of TH17 cells as we have demonstrated with one rerecruited patient has to be further analyzed.

• Local application of basic fibroblast growth factor increases the risk of local infection after trauma: an in-vitro and in-vivo study in rats.

  Authors: Thomas Kälicke, Manfred Köller, Thomas Manfred Frangen, Urs Schlegel, Oliver Sprutacz, Gert Printzen, Gert Muhr, Stephan Arens

  Acta orthopaedica. 03/2007; 78(1):63-73.

  INTRODUCTION: Local application of growth factors to stimulate wound and fracture healing is attracting increasing interest. We studied the effect of local application of a potent angiogenic growthINTRODUCTION: Local application of growth factors to stimulate wound and fracture healing is attracting increasing interest. We studied the effect of local application of a potent angiogenic growth factor, basic fibroblast growth factor (bFGF), on resistance to local infection after soft tissue trauma. METHODS: For in-vitro and in-vivo experiments, we used recombinant human bFGF. The in-vitro investigations were performed by isolation of human leukocyte fractions, cytokine analysis, phagocytosis assay, flow cytometry, and LDH assay. For the in-vivo investigation, a paired comparison of infection rates was carried out on Sprague-Dawley rats after standardized, closed soft tissue trauma and local, percutaneous bacterial inoculation of different concentrations of Staphylococcus aureus (2 x 10(4) to 2 x 10(7) colony-forming units (cfu)). The lower leg was treated with 1, 10 or 100 ng bFGF (16 animals for each concentration) and without bFGF (16 animals). RESULTS: Cytotoxic reactions due to the concentrations of bFGF used could be excluded in the in-vitro tests since incubations of isolated peripheral blood mononuclear cells (PBMCs) with increasing concentrations of bFGF for 24 h did not lead to an increase in the release of lactate dehydrogenase in the culture supernatants compared to corresponding control incubations without any bFGF added. A significant increase in cytokine release was observed after the co-incubation of PBMCs with 100 or 200 ng of the same bFGF that was used for the animal experiments. Furthermore, the capacity of phagocytes in whole blood to phagocytose bacteria was suppressed in the presence of 100 ng exogenously added bFGF. We found continuously reduced granulocytic phagocytosis in FGF-supplemented blood compared to non-supplemented blood. In the in-vivo investigation, the infection rate for the group without bFGF was 0.25. In the groups with 1, 10 and 100 ng bFGF, the infection rates were 0.5, 0.7 and 0.8, respectively. A dose-dependent increase in infection rate was observed after local application of bFGF, compared to the untreated control group. The difference in infection rates for the groups in which 10 and 100 ng bFGF was used, relative to the group without bFGF, was statistically significant. INTERPRETATION: If these initial results are confirmed for other potent angiogenic growth factors, then the local use of growth factors for stimulation of wound and bone healing--a main focus of current research in traumatology--will have to be reconsidered and preceded with a strict evaluation of the risks and benefits.

• Bacterial adherence to tantalum versus commonly used orthopedic metallic implant materials.

  Authors: Thomas A Schildhauer, Bruce Robie, Gert Muhr, Manfred Köller

  Journal of orthopaedic trauma. 08/2006; 20(7):476-84.

  OBJECTIVES: Evaluation of bacterial adhesion to pure tantalum and tantalum-coated stainless steel versus commercially pure titanium, titanium alloy (Ti-6Al-4V), and grit-blasted and polishedOBJECTIVES: Evaluation of bacterial adhesion to pure tantalum and tantalum-coated stainless steel versus commercially pure titanium, titanium alloy (Ti-6Al-4V), and grit-blasted and polished stainless steel. DESIGN: Experimental in vitro cell culture study using Staphylococcus aureus and Staphylococcus epidermidis to evaluate qualitatively and quantitatively bacterial adherence to metallic implants. METHODS: A bacterial adhesion assay was performed by culturing S. aureus (ATCC 6538) and S. epidermidis (clinical isolate) for one hour with tantalum, tantalum-coated stainless steel, titanium, titanium alloy, grit-blasted and polished stainless steel metallic implant discs. Adhered living and dead bacteria were stained using a 2-color fluorescence assay. Adherence was then quantitatively evaluated by fluorescence microscopy and digital image processing. Qualitative adherence of the bacteria was analyzed with a scanning electron microscope. The quantitative data were related to the implant surface roughness (Pa-value) as measured by confocal laser scanning microscopy. RESULTS: Bacterial adherence of S. aureus varied significantly (p = 0.0035) with the type of metallic implant. Pure tantalum presented with significantly (p < 0.05) lower S. aureus adhesion compared to titanium alloy, polished stainless steel, and tantalum-coated stainless steel. Furthermore, pure tantalum had a lower, though not significantly, adhesion than commercially pure titanium and grit-blasted stainless steel. Additionally, there was a significantly higher S. aureus adherence to titanium alloy than to commercially pure titanium (p = 0.014). S. epidermidis adherence was not significantly different among the tested materials. There was no statistically significant correlation between bacterial adherence and surface roughness of the tested implants. CONCLUSIONS: Pure tantalum presents with a lower or similar S. aureus and S. epidermidis adhesion when compared with commonly used materials in orthopedic implants. CLINICAL IMPLICATION: Because bacterial adhesion is an important predisposing factor in the development of clinical implant infection, tantalum may offer benefits as an adjunct or alternative material compared with current materials commonly used for orthopedic implants.

• Effect on infection resistance of a local antiseptic and antibiotic coating on osteosynthesis implants: an in vitro and in vivo study.

  Authors: Thomas Kälicke, Jörg Schierholz, Urs Schlegel, Thomas Manfred Frangen, Manfred Köller, Gert Printzen, Dominik Seybold, Stefan Klöckner, Gert Muhr, Stephan Arens

  Journal of orthopaedic research : official publication of the Orthopaedic Research Society. 08/2006; 24(8):1622-40.

  The purpose of this study was to acquire information about the effect of an antibacterial and biodegradable poly-L-lactide (PLLA) coated titanium plate osteosynthesis on local infection resistance.The purpose of this study was to acquire information about the effect of an antibacterial and biodegradable poly-L-lactide (PLLA) coated titanium plate osteosynthesis on local infection resistance. For our in vitro and in vivo experiments, we used six-hole AO DC minifragment titanium plates. The implants were coated with biodegradable, semiamorphous PLLA (coating about 30 microm thick). This acted as a carrier substance to which either antibiotics or antiseptics were added. The antibiotic we applied was a combination of Rifampicin and fusidic acid; the antiseptic was a combination of Octenidin and Irgasan. This produced the following groups: Group I: six-hole AO DC minifragment titanium plate without PLLA; Group II: six-hole AO DC minifragment titanium plate with PLLA without antibiotics/antiseptics; Group III: six-hole AO DC minifragment titanium plate with PLLA + 3% Rifampicin and 7% fusidic acid; Group IV: six-hole AO DC minifragment titanium plate with PLLA + 2% Octenidin and 8% Irgasan. In vitro, we investigated the degradation and the release of the PLLA coating over a period of 6 weeks, the bactericidal efficacy of antibiotics/antiseptics after their release from the coating and the bacterial adhesion of Staphylococcus aureus to the implants. In vivo, we compared the infection rates in white New Zealand rabbits after titanium plate osteosynthesis of the tibia with or without antibacterial coating after local percutaneous bacterial inoculations at different concentrations (2 x 10(5)-2 x 10(8)): The plate, the contaminated soft tissues and the underlying bone were removed under sterile conditions after 28 days and quantitatively evaluated for bacterial growth. A stepwise experimental design with an "up-and-down" dosage technique was used to adjust the bacterial challenge in the area of the ID50 (50% infection dose). Statistical evaluation of the differences between the infection rates of both groups was performed using the two-sided Fisher exact test (p < 0.05). Over a period of 6 weeks, a continuous degradation of the PLLA coating of 13%, on average, was seen in vitro in 0.9% NaCl solution. The elution tests on titanium implants with antibiotic or antiseptic coatings produced average release values of 60% of the incorporated antibiotic or 62% of the incorporated antiseptic within the first 60 min. This was followed by a much slower, but nevertheless continuous, release of the incorporated antibiotic and antiseptic over days and weeks. At the end of the test period of 42 days, 20% of the incorporated antibiotic and 15% of the incorporated antiseptic had not yet been released from the coating. The antibacterial effect of the antibiotic/antiseptic is not lost by integrating it into the PLLA coating. The overall infection rate in the in vivo investigation was 50%. For Groups I and II the infection rate was both 83% (10 of 12 animals). In Groups III and IV with antibacterial coating, the infection rate was both 17% (2 of 12 animals). The ID50 in the antibacterial coated Groups III and IV was recorded as 1 x 10(8) CFU, whereas the ID50 values in the Groups I and II without antibacterial coating were a hundred times lower at 1 x 10(6) CFU, respectively. The difference between the groups with and without antibacterial coating was statistically significant (p = 0.033). Using an antibacterial biodegradable PLLA coating on titanium plates, a significant reduction of infection rate in an in vitro and in vivo investigation could be demonstrated. For the first time, to our knowledge, we were able to show, under standardized and reproducible conditions, that an antiseptic coating leads to the same reduction in infection rate as an antibiotic coating. Taking the problem of antibiotic-induced bacterial resistance into consideration, we thus regard the antiseptic coating, which shows the same level of effectiveness, as advantageous.

• Morphological characterization and in vitro biocompatibility of a porous nickel-titanium alloy.

  Authors: Oleg Prymak, Denise Bogdanski, Manfred Köller, Stefan A Esenwein, Gert Muhr, Felix Beckmann, Tilmann Donath, Michel Assad, Matthias Epple

  Biomaterials. 10/2005; 26(29):5801-7.

  Disks consisting of macroporous nickel-titanium alloy (NiTi, Nitinol, Actipore) are used as implants in clinical surgery, e.g. for fixation of spinal dysfunctions. The morphological properties wereDisks consisting of macroporous nickel-titanium alloy (NiTi, Nitinol, Actipore) are used as implants in clinical surgery, e.g. for fixation of spinal dysfunctions. The morphological properties were studied by scanning electron microscopy (SEM) and by synchrotron radiation-based microtomography (SRmuCT). The composition was studied by X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and energy-dispersive X-ray spectroscopy (EDX). The mechanical properties were studied with temperature-dependent dynamical mechanical analysis (DMA). Studies on the biocompatibility were performed by co-incubation of porous NiTi samples with isolated peripheral blood leukocyte fractions (polymorphonuclear neutrophil granulocytes, PMN; peripheral blood mononuclear leukocytes, PBMC) in comparison with control cultures without NiTi samples. The cell adherence to the NiTi surface was analyzed by fluorescence microscopy and scanning electron microscopy. The activation of adherent leukocytes was analyzed by measurement of the released cytokines using enzyme-linked immunosorbent assay (ELISA). The cytokine response of PMN (analyzed by the release of IL-1ra and IL-8) was not significantly different between cell cultures with or without NiTi. There was a significant increase in the release of IL-1ra (p<0.001), IL-6 (p<0.05), and IL-8 (p<0.05) from PBMC in the presence of NiTi samples. In contrast, the release of TNF-alpha by PBMC was not significantly elevated in the presence of NiTi. IL-2 was released from PBMC only in the range of the lower detection limit in all cell cultures. The material, clearly macroporous with an interconnecting porosity, consists of NiTi (martensite; monoclinic, and austenite; cubic) with small impurities of NiTi2 and possibly NiC(x). The material is not superelastic upon manual compression and shows a good biocompatibility.

• Analysis of systemic interleukin-11 after major trauma.

  Authors: Christian Schinkel, Marc Wick, Gert Muhr, Manfred Köller

  Shock (Augusta, Ga.). 02/2005; 23(1):30-4.

  Recent data have shown that anti-inflammatory responses to major injury occur immediately after trauma. Interleukin 11 (IL-11), a member of the IL-6 family, is a pleiotropic cytokine withRecent data have shown that anti-inflammatory responses to major injury occur immediately after trauma. Interleukin 11 (IL-11), a member of the IL-6 family, is a pleiotropic cytokine with hematopoietic, osteotrophic, and mucosa protective properties, as well as anti-inflammatory functions. IL-11 inhibits synthesis of proinflammatory cytokines, promotes a Th2-type immune response, and improves outcome after shock and sepsis in different animal models. To further investigate the role of IL-11 in the human posttraumatic immune response, we measured plasma levels of IL-11 in 216 multiple-injured patients (mean age of 40 +/- 16 [range 11-81] years; Injury Severity Score [ISS] of 31 +/- 11 [range 16-66] points; 52 women and 164 men) after injury and correlated this with demographics, clinical course, and other laboratory parameters. IL-11 was significantly elevated in polytraumatized patients compared with healthy donors (P <0.0001). The time course of IL-11 in surviving patients was an initial increase after trauma with a decrease during the first 4 weeks, whereas nonsurvivors (n=34) had a significant increase later after injury (4 weeks). IL-11 was significantly higher after abdominal trauma and in men. No correlation between systemic IL-11 and ISS or age was detected. IL-11 correlated significantly with other pro- and anti-inflammatory cytokines such as IL-18. Our data demonstrate elevated levels of systemic IL-11 after multiple injuries; however, the role of a posttraumatic increase of IL-11 has to be further analyzed. In contrast to IL-6, IL-11 in plasma does not correlate with trauma severity and seems to have no clinical relevance to outcome prediction after trauma.

• Inhibition of PMN apoptosis after adherence to dip-coated calcium phosphate surfaces on a NiTi shape memory alloy.

  Authors: Denise Bogdanski, Stefan A Esenwein, Oleg Prymak, Matthias Epple, Gert Muhr, Manfred Köller

  Biomaterials. 09/2004; 25(19):4627-32.

  Nickel-titanium shape-memory alloys (NiTi-SMA) were coated with calcium phosphate by dipping in oversaturated calcium phosphate solution (CaP-coating). Polymorphonuclear neutrophil granulocytes (PMN)Nickel-titanium shape-memory alloys (NiTi-SMA) were coated with calcium phosphate by dipping in oversaturated calcium phosphate solution (CaP-coating). Polymorphonuclear neutrophil granulocytes (PMN) belong to the first cells which will adhere to implant materials. We analyzed the apoptosis of isolated human PMN after cell culture on non-coated and CaP-coated NiTi-SMA by light and scanning electron microscopy (cell morphology) and by flow cytometry (DNA-fragmentation). In contrast to PMN adherent to non-coated NiTi-SMA, the apoptosis of PMN adherent CaP-coated samples was inhibited. Cell culture media obtained from cultured leukocytes with CaP-coatings (conditioned media, CM) were able to transfer the apoptosis inhibiting activities to freshly isolated PMN. There was a significant (p<0.01) increase in GM-CSF, IL-8, IL-6, and TNF-alpha within CM obtained from coated versus non-coated NiTi-SMA as was determined by ELISA.

• Linezolid penetration into bone and joint tissues infected with methicillin-resistant staphylococci.

  Authors: Friedrich Kutscha-Lissberg, Ute Hebler, Gert Muhr, Manfred Köller

  Antimicrobial agents and chemotherapy. 01/2004; 47(12):3964-6.

  Penetration of linezolid into bone and joint tissues was studied by high-performance liquid chromatography in 13 patients suffering from implant-associated infections with methicillin-resistantPenetration of linezolid into bone and joint tissues was studied by high-performance liquid chromatography in 13 patients suffering from implant-associated infections with methicillin-resistant staphylococci. Mean concentrations of linezolid in infected tissues were greater than 10 mg/liter in a sampling time range of 35 to 124 min after administration of the preoperative dose, except in bone specimens, where they reached 3.9 +/- 2.0 mg/liter.

• Calcium phosphate coating of nickel-titanium shape-memory alloys. Coating procedure and adherence of leukocytes and platelets.

  Authors: Jongsik Choi, Denise Bogdanski, Manfred Köller, Stefan A Esenwein, Dietmar Müller, Gert Muhr, Matthias Epple

  Biomaterials. 10/2003; 24(21):3689-96.

  Nickel-titanium shape-memory alloys (NiTi-SMA) were coated with calcium phosphate by dipping in oversaturated calcium phosphate solution. The layer thickness (typically 5-20 micrometer) can be variedNickel-titanium shape-memory alloys (NiTi-SMA) were coated with calcium phosphate by dipping in oversaturated calcium phosphate solution. The layer thickness (typically 5-20 micrometer) can be varied by choice of the immersion time. The porous nature of the layer of microcrystals makes it mechanically stable enough to withstand both the shape-memory transition upon cooling and heating and also strong bending of the material (superelastic effect). This layer may improve the biocompatibility of NiTi-SMA, particulary for osteosynthetic devices by creating a more physiological surface and by restricting a potential nickel release. The adherence of human leukocytes (peripheral blood mononuclear cells and polymorphonuclear neutrophil granulocytes) and platelets to the calcium phosphate layer was analyzed in vitro. In comparison to non-coated NiTi-SMA, leukocytes and platelets showed a significantly increased adhesion to the coated NiTi-SMA.

• Cytokines and erythropoietin in the blood of patients with erythroblastemia.

  Authors: Axel Stachon, Karsten Eisenblätter, Manfred Köller, Tim Holland-Letz, Michael Krieg

  Acta haematologica. 02/2003; 110(4):204-6.

• Easy assessment of the biocompatibility of Ni-Ti alloys by in vitro cell culture experiments on a functionally graded Ni-NiTi-Ti material.

  Authors: Denise Bogdanski, Manfred Köller, Dietmar Müller, Gert Muhr, Martin Bram, Hans Peter Buchkremer, Detlev Stöver, Jongsik Choi, Matthias Epple

  Biomaterials. 01/2003; 23(23):4549-55.

  The biocompatibility of nickel-titanium alloys was investigated by single-culture experiments on functionally graded samples with a stepwise change in composition from pure nickel to pure titanium,The biocompatibility of nickel-titanium alloys was investigated by single-culture experiments on functionally graded samples with a stepwise change in composition from pure nickel to pure titanium, including an Ni-Ti shape memory alloy for a 50:50 mixture. This approach permitted a considerable decrease of experimental resources by simultaneously studying a full variation of composition. The results indicate a good biocompatibility for a nickel content up to about 50%. The cells used in the biocompatibility studies comprised osteoblast-like osteosarcoma cells (SAOS-2, MG-63), primary human osteoblasts (HOB), and murine fibroblasts (3T3).

• Morphological characterization and in vitro biocompatibility of a porous nickel–titanium alloy

  Authors: Oleg Prymak, Denise Bogdanski, Manfred Köller, Stefan A. Esenwein, Gert Muhr, Felix Beckmann, Tilmann Donath, Michel Assad, Matthias Epple

  Biomaterials.

  Disks consisting of macroporous nickel–titanium alloy (NiTi, Nitinol®, Actipore®) are used as implants in clinical surgery, e.g. for fixation of spinal dysfunctions. The morphological properties wereDisks consisting of macroporous nickel–titanium alloy (NiTi, Nitinol®, Actipore®) are used as implants in clinical surgery, e.g. for fixation of spinal dysfunctions. The morphological properties were studied by scanning electron microscopy (SEM) and by synchrotron radiation-based microtomography (SRμCT). The composition was studied by X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and energy-dispersive X-ray spectroscopy (EDX). The mechanical properties were studied with temperature-dependent dynamical mechanical analysis (DMA). Studies on the biocompatibility were performed by co-incubation of porous NiTi samples with isolated peripheral blood leukocyte fractions (polymorphonuclear neutrophil granulocytes, PMN; peripheral blood mononuclear leukocytes, PBMC) in comparison with control cultures without NiTi samples. The cell adherence to the NiTi surface was analyzed by fluorescence microscopy and scanning electron microscopy. The activation of adherent leukocytes was analyzed by measurement of the released cytokines using enzyme-linked immunosorbent assay (ELISA). The cytokine response of PMN (analyzed by the release of IL-1ra and IL-8) was not significantly different between cell cultures with or without NiTi. There was a significant increase in the release of IL-1ra (p<0.001), IL-6 (p<0.05), and IL-8 (p<0.05) from PBMC in the presence of NiTi samples. In contrast, the release of TNF-α by PBMC was not significantly elevated in the presence of NiTi. IL-2 was released from PBMC only in the range of the lower detection limit in all cell cultures. The material, clearly macroporous with an interconnecting porosity, consists of NiTi (martensite; monoclinic, and austenite; cubic) with small impurities of NiTi2 and possibly NiCx. The material is not superelastic upon manual compression and shows a good biocompatibility.

• Sterilization of heat-sensitive silicone implant material by low-pressure gas plasma.

  Authors: Joerg Hauser, Stefan-Alexander Esenwein, Peter Awakowicz, Hans-Ulrich Steinau, Manfred Köller, Helmut Halfmann

  Biomedical instrumentation & technology / Association for the Advancement of Medical Instrumentation. 45(1):75-9.

  In recent years, plasma treatment of medical devices and implant materials has gained more and more acceptance. Inactivation of microorganisms by exposure to ultraviolet (UV) radiation produced byIn recent years, plasma treatment of medical devices and implant materials has gained more and more acceptance. Inactivation of microorganisms by exposure to ultraviolet (UV) radiation produced by plasma discharges and sterilization of medical implants and instruments is one possible application of this technique. The aim of this study was to evaluate the effectiveness of this sterilization technique on silicone implant material. Bacillus atrophaeus spores (10(6) colony-forming units [CFUs]) were sprayed on the surfaces of 12 silicone implant material samples. Four plasma sets with different gas mixtures (argon [Ar], argon-oxygen [Ar:O(2)], argon-hydrogen [Ar:H(2)] and argon-nitrogen [Ar:N(2)]) were tested for their antimicrobial properties. Post-sterilization mechanical testing of the implant material was performed in order to evaluate possible plasma-induced structural damage. The inductively coupled low-pressure plasma technique can achieve fast and efficient sterilization of silicone implant material without adverse materials effects. All four gas mixtures led to a significant spore reduction, and no structural damage to the implant material could be observed.