S3-Guideline non-traumatic adult femoral head necrosis.

INTRODUCTION: The treatment of adult non-traumatic avascular necrosis of the femoral head (AVN; N-ANFH) within an estimated incidence of 5000-7000 cases per annum in Germany remains a challenge. Risk factors include steroids, alcohol abuse, chemotherapy and immunosuppressive medication, but a genetic predisposition has been suggested. Early diagnosis of this often bilateral disease process is essential for successful conservative or joint preserving surgical management. In this review, we present the update German consensus S3 guideline "diagnosis and management for N-ANFH" as a concise summary. MATERIALS AND METHODS: This systematic review is based on the published literature from January 1, 1970 to April 31, 2013 (German and English language). Inclusion criteria were systematic reviews, meta-analyses and relevant peer review publications. We identified a total of 3715 related publications, of which 422 were suitable according to the SIGN criteria, but only 159 fulfilled our inclusion criteria. RESULTS AND CONCLUSIONS: Clinical suspicion of N-ANFH mandates radiographic evaluation. If radiographs are normal MRI scans are recommended, which should be evaluated according to the ARCO-classification. Differential diagnoses include transient osteoporosis, bone bruise, insufficiency fracture and destructive arthropathy. Untreated, subchondral fractures commonly occur within 2 years, during which the risk for contralateral involvement is high-thereafter unlikely. Conservative management with Ilomedin and Alendronat can be tried, but other pharmacological or physical treatments are inappropriate. No specific joint preserving procedure can be recommended, but core decompression should be considered in early stages if necrosis is <30 %. In ARCO stages IIIc or IV total hip arthroplasty (THA) should be contemplated, which offers similar outcome compared to osteoarthritis. Young age is the main risk factor for higher revision rates after THA for N-ANFH.

[Osteomalacia and vitamin D deficiency]. / Osteomalazie und Vitamin-D-Hypovitaminose.

BACKGROUND: Vitamin D and calcium deficiency has a higher incidence in the orthopedic-trauma surgery patient population than generally supposed. In the long term this can result in osteomalacia, a form of altered bone mineralization in adults, in which the cartilaginous, non-calcified osteoid does not mature to hard bone. AIM: The current value of vitamin D and its importance for bones and other body cells are demonstrated. RESULTS: The causes of vitamin D deficiency are insufficient sunlight exposure, a lack of vitamin D3 and calcium, malabsorption, and rare alterations of VDR signaling and phosphate metabolism. The main symptoms are bone pain, fatigue fractures, muscular cramps, muscle pain, and gait disorders, with an increased incidence of falls in the elderly. Osteopathies induced by pharmaceuticals, tumors, rheumatism or osteoporosis have to be considered as the main differential diagnoses. CONCLUSIONS: In addition to the recording of symptoms and medical imaging, the diagnosis of osteomalacia should be ensured by laboratory parameters. Adequate treatment consists of the high-dose intake of vitamin D3 and the replacement of phosphate if deficient. Vitamin D is one of the important hormone-like vitamins and is required in all human cells. Deficiency of vitamin D has far-reaching consequences not only for bone, but also for other organ systems.

Integrated functional and spatial profiling of tumour immune responses induced by immunotherapy: the iPROFILER platform.

BACKGROUND: Cancer immunotherapy elicits functional activation and changes in immune cell distribution in cancer. Tumour heterogeneity is a reason for treatment failure but is difficult to capture in experimental settings. This proof-of-principle study describes the integrated functional and digital spatial profiling platform iPROFILER to capture in-situ immune activation patterns with high precision. MATERIALS AND METHODS: iPROFILER combines an algorithm-based image analysis approach for spatial profiling with functional analyses of patient-derived tumour fragments (PDTFs). This study utilized a folate receptor 1 (FOLR1)xCD3 bispecific antibody in dual-affinity re-targeting (DART) format as a tool for inducing T-cell responses in patient tumour samples, and an in-depth investigation of the immune perturbations induced in the tumour microenvironment was performed. RESULTS: Ex-vivo DART stimulation induces upregulation of multiple activation markers in CD4+ and CD8+ T-cell populations and secretion of pro-inflammatory cytokines in FOLR1-positive tumour specimens. This response was reduced or absent in tissue samples that did not express FOLR1. Immunological responses were driven by a strong induction of interferon gamma (IFNγ) and IFNγ-induced chemokines suggestive of activation of cytotoxic or Th1-like T cells. Ex-vivo DART treatment led to a numerical increase in effector T cells and an upregulation of immune activation markers in the tumour microenvironment as captured by digital image analysis. Analysis of immune activation in tumour and stromal regions further supported the potential of the platform to measure local differences in cell-type-specific activation patterns. CONCLUSIONS: iPROFILER effectively combines functional and spatial readouts to investigate immune responses ex vivo in human tumour samples.

Cell adhesion molecules NgCAM and axonin-1 form heterodimers in the neuronal membrane and cooperate in neurite outgrowth promotion.

The axonal surface glycoproteins neuronglia cell adhesion molecule (NgCAM) and axonin-1 promote cell-cell adhesion, neurite outgrowth and fasciculation, and are involved in growth cone guidance. A direct binding between NgCAM and axonin-1 has been demonstrated using isolated molecules conjugated to the surface of fluorescent microspheres. By expressing NgCAM and axonin-1 in myeloma cells and performing cell aggregation assays, we found that NgCAM and axonin-1 cannot bind when present on the surface of different cells. In contrast, the cocapping of axonin-1 upon antibody-induced capping of NgCAM on the surface of CV-1 cells coexpressing NgCAM and axonin-1 and the selective chemical cross-linking of the two molecules in low density cultures of dorsal root ganglia neurons indicated a specific and direct binding of axonin-1 and Ng-CAM in the plane of the same membrane. Suppression of the axonin-1 translation by antisense oligonucleotides prevented neurite outgrowth in dissociated dorsal root ganglia neurons cultured on an NgCAM substratum, indicating that neurite outgrowth on NgCAM substratum requires axonin-1. Based on these and previous results, which implicated NgCAM as the neuronal receptor involved in neurite outgrowth on NgCAM substratum, we concluded that neurite outgrowth on an NgCAM substratum depends on two essential interactions of growth cone NgCAM: a trans-interaction with substratum NgCAM and a cis-interaction with axonin-1 residing in the same growth cone membrane.

Neurite fasciculation mediated by complexes of axonin-1 and Ng cell adhesion molecule.

Neural cell adhesion molecules composed of immunoglobulin and fibronectin type III-like domains have been implicated in cell adhesion, neurite outgrowth, and fasciculation. Axonin-1 and Ng cell adhesion molecule (NgCAM), two molecules with predominantly axonal expression exhibit homophilic interactions across the extracellular space (axonin- 1/axonin-1 and NgCAM/NgCAM) and a heterophilic interaction (axonin-1-NgCAM) that occurs exclusively in the plane of the same membrane (cis-interaction). Using domain deletion mutants we localized the NgCAM homophilic binding in the Ig domains 1-4 whereas heterophilic binding to axonin-1 was localized in the Ig domains 2-4 and the third FnIII domain. The NgCAM-NgCAM interaction could be established simultaneously with the axonin-1-NgCAM interaction. In contrast, the axonin-1-NgCAM interaction excluded axonin-1/axonin-1 binding. These results and the examination of the coclustering of axonin-1 and NgCAM at cell contacts, suggest that intercellular contact is mediated by a symmetric axonin-12/NgCAM2 tetramer, in which homophilic NgCAM binding across the extracellular space occurs simultaneously with a cis-heterophilic interaction of axonin-1 and NgCAM. The enhanced neurite fasciculation after overexpression of NgCAM by adenoviral vectors indicates that NgCAM is the limiting component for the formation of the axonin-12/NgCAM2 complexes and, thus, neurite fasciculation in DRG neurons.

A direct interaction of axonin-1 with NgCAM-related cell adhesion molecule (NrCAM) results in guidance, but not growth of commissural axons.

An interaction of growth cone axonin-1 with the floor-plate NgCAM-related cell adhesion molecule (NrCAM) was shown to play a crucial role in commissural axon guidance across the midline of the spinal cord. We now provide evidence that axonin-1 mediates a guidance signal without promoting axon elongation. In an in vitro assay, commissural axons grew preferentially on stripes coated with a mixture of NrCAM and NgCAM. This preference was abolished in the presence of anti-axonin-1 antibodies without a decrease in neurite length. Consistent with these findings, commissural axons in vivo only fail to extend along the longitudinal axis when both NrCAM and NgCAM interactions, but not when axonin-1 and NrCAM or axonin-1 and NgCAM interactions, are perturbed. Thus, we conclude that axonin-1 is involved in guidance of commissural axons without promoting their growth.

Proposal for a histopathological consensus classification of the periprosthetic interface membrane.

AIMS: The introduction of clearly defined histopathological criteria for a standardised evaluation of the periprosthetic membrane, which can appear in cases of total joint arthroplasty revision surgery. METHODS: Based on histomorphological criteria, four types of periprosthetic membrane were defined: wear particle induced type (detection of foreign body particles; macrophages and multinucleated giant cells occupy at least 20% of the area; type I); infectious type (granulation tissue with neutrophilic granulocytes, plasma cells and few, if any, wear particles; type II); combined type (aspects of type I and type II occur simultaneously; type III); and indeterminate type (neither criteria for type I nor type II are fulfilled; type IV). The periprosthetic membranes of 370 patients (217 women, 153 men; mean age 67.6 years, mean period until revision surgery 7.4 years) were analysed according to the defined criteria. RESULTS: Frequency of histopathological membrane types was: type I 54.3%, type II 19.7%, type III 5.4%, type IV 15.4%, and not assessable 5.1%. The mean period between primary arthroplasty and revision surgery was 10.1 years for type I, 3.2 years for type II, 4.5 years for type III and 5.4 years for type IV. The correlation between histopathological and microbiological diagnosis was high (89.7%), and the inter-observer reproducibility sufficient (85%). CONCLUSION: The classification proposed enables standardised typing of periprosthetic membranes and may serve as a tool for further research on the pathogenesis of the loosening of total joint replacement. The study highlights the importance of non-infectious, non-particle induced loosening of prosthetic devices in orthopaedic surgery (membrane type IV), which was observed in 15.4% of patients.

WITHDRAWN: Immunohistochemical localization of Ih channel HCN3 in the rat brain.

Ahead of Print article withdrawn by publisher

Phage display of combinatorial antibody libraries.

The selection of antibodies from combinatorial libraries displayed on the surface of filamentous phage has become an important methodology for the generation of reagent, diagnostic, and therapeutic molecules and for the study of natural immune responses. Using this technique, antibody genes have been cloned from multiple species or expressed directly from large man-made repertoires of antibody-encoding genes. Recent studies demonstrate that the technique allows for the in vitro evolution of antibodies to create molecules whose affinity for antigen exceeds that observed in nature.

[S3 Guideline. Part 1: Diagnosis and Differential Diagnosis of Non-Traumatic Adult Femoral Head Necrosis]. / S3-Leitline. Teil 1: Diagnostik und Differenzialdiagnostik der atraumatischen Femurkopfnekrose (aFKN) des Erwachsenen.

Non-traumatic femoral head necrosis (FHN) is primarily a disease of the middle-aged adult. Early diagnosis, at a time with lacking or minimal clinical symptoms, is mandatory to consider conservative therapy or joint preserving operations as a therapeutic option. The new German S3 guideline about diagnosis and therapy of FHN is a cooperative effort of five professional medical societies, overall headed by the Deutsche Gesellschaft für Orthopädie und Orthopädische Chirurgie (DGOOC). This review (part I/III) cites and explains the statements of the S3 guideline as agreed on the use of imaging methods for diagnosis of FHN. A diagnostic algorithm is presented. FHN clinically has to be considered in case of equivocal pain of a hip joint with a minimum of 6 weeks duration, when risk factors can be revealed, groin pain at clinical investigation, limping, pain or limitation of movement in case of load, and no obvious differential diagnoses. Is an FHN clinically suspected, primarily radiographs of the pelvis ap and a Lauenstein projection of the hip involved should be carried out. When the radiographs are normal, an MRI of the hips should follow routinely. MRI allows the diagnosis of FNH with high accuracy. Furthermore, MRI reveals the site and the size of the necrotic area involved and evaluates the integrity of the joint surface and subchondral fractures. When ARCO stage II (ARCO: Association Research Circulation Osseous) is diagnosed and MRI does not allow one to determine the joint surface with certainty, a CT of the hip joints should be performed. The S3 guideline explains and recommends the use of the ARCO classification. Although, this classification of 1993 is still largely based on radiographs, the pragmatic use of an "extended" version seems reasonable. Today, classical radiographic criteria like impression of the joint surface and subchondral fractures ("crescent sign") are better to be evaluated by MRI, in cases of subtle findings MRI is even surpassed by CT. The extent of the necrosis in the femoral head as well as the size of the surface area involved is best revealed with MRI. Additionally, in the era of cross sectional imaging a stage "0" seems obsolete. The guideline also addresses practically important considerations about the differential diagnosis of misleading MRI findings. This especially holds true for bone marrow oedema in the femoral head which may be misinterpreted. The differentiating features between FHN, transient bone marrow oedema and destructive arthropathy are discussed.

[S3 Guideline. Part 3: Non-Traumatic Avascular Necrosis in Adults - Surgical Treatment of Atraumatic Avascular Femoral Head Necrosis in Adults]. / S3-Leitlinie. Teil 3: Atraumatische Femurkopfnekrose des Erwachsenen - Operative Therapie der atraumatischen Femurkopfnekrose des Erwachsenen.

The present article describes the guidelines for the surgical treatment of atraumatic avascular necrosis (aFKN). These include joint preserving and joint replacement procedures. As part of the targeted literature, 43 publications were included and evaluated to assess the surgical treatment. According to the GRADE and SIGN criteria level of evidence (LoE), grade of recommendation (EC) and expert consensus (EK) were listed for each statement and question. The analysed studies have shown that up to ARCO stage III, joint-preserving surgery can be performed. A particular joint-preserving surgery currently cannot be recommended as preferred method. The selection of the method depends on the extent of necrosis. Core decompression performed in stage ARCO I (reversible early stage) or stage ARCO II (irreversible early stage) with medial or central necrosis with an area of less than 30 % of the femoral head shows better results than conservative therapy. In ARCO stage III with infraction of the femoral head, the core decompression can be used for a short-term pain relief. For ARCO stage IIIC or stage IV core decompression should not be performed. In these cases, the indication for implantation of a total hip replacement should be checked. Additional therapeutic procedures (e.g., osteotomies) and innovative treatment options (advanced core decompression, autologous bone marrow, bone grafting, etc.) can be discussed in the individual case. In elective hip replacement complications and revision rates have been clearly declining for decades. In the case of an underlying aFKN, however, previous joint-preserving surgery (osteotomies and grafts in particular) can complicate the implantation of a THA significantly. However, the implant life seems to be dependent on the aetiology. Higher revision rates for avascular necrosis are particularly expected in sickle cell disease, Gaucher disease, or kidney transplantation patients. Furthermore, the relatively young age of the patient with avascular necrosis should be seen as the main risk factor for higher revision rate. The results after resurfacing (today with known restricted indications) and cemented as well as cementless THA in aFKN are comparable for the appropriate indication to those in coxarthrosis or other diagnoses. Regardless of the underlying disease endoprosthetic treatment in aFKN leads to good results. Both cemented and cementless fixation techniques can be recommended.

[S3 guideline. Part 2: Non-Traumatic Avascular Femoral Head Necrosis in Adults - Untreated Course and Conservative Treatment]. / S3-Leitlinie. Teil 2: Atraumatische Femurkopfnekrose des Erwachsenen - unbehandelter Verlauf und konservative Behandlung.

BACKGROUND: In Germany there are 5000 to 7000 new cases of atraumatic avascular necrosis of the femoral head in adults per year. It occurs mostly in middle age. An increased frequency of idiopathic cases can be observed. Chemotherapy, corticoids and kidney transplants are frequently associated with the disease. In most cases the disease occurs on both sides. Early diagnosis is of particular importance, since in early stages it is most likely to avoid late damage with joint destruction. Whereas previously the temporary operational joint preservation and subsequent joint replacement were often the only option of treatment, conservative and joint-preserving measures today play an increasing role. MATERIAL AND METHODS: After the AWMF guidelines for S3 guideline clinical questions were formulated. Over the period from 01/01/1970 to 31/05/2013 a literature search was conducted. Systematic reviews, metaanalyses, original papers and clinical trials of all designs were evaluated. There were a total of 3715 references, of which 422 for the assessment regarding SIGN were eligible and finally 180 were in accord with the defined inclusion and exclusion criteria. For the untreated course and the assessment of conservative measures, a total of 42 references was suitable. In formulating the recommendations the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system was used, which distinguishes A "shall", B "should" and 0 "can". RESULTS AND CONCLUSION: If left untreated, the aFKN within 2 years leads to a subchondral fracture and subsequent collapse. After the diagnosis of femoral head necrosis, the risk of a disease of the opposite side is high within the next 2 years, then unlikely. The sole conservative treatment brings no benefit for the treatment of atraumatic avascular necrosis in the adult. Although it improves function, less pain can be obtained, and surgical intervention can be delayed, the progression is not stopped. Conservative treatment must therefore always be part of the overall treatment. In ARCO stage I to II Iloprost may be considered as a pharmacological approach to reduce the pain and the bone marrow oedema. This also applies to alendronate. Since this is an off-label use, and thus a therapeutic trial, an appropriate patient education must take place. For the use of anticoagulants and statins, there is no recommendation. Also the hyperbaric oxygen therapy, shock waves and pulsating electromagnetic fields or electrical stimulation cannot be recommended.

Tumor antigen ROR1 targeted drug delivery mediated selective leukemic but not normal B-cell cytotoxicity in chronic lymphocytic leukemia.

Selective cytotoxicity to cancer cells without compromising their normal counterparts pose a huge challenge for traditional drug design. Here we developed a tumor antigen-targeted delivery of immunonanoparticle carrying a novel non-immunosuppressive FTY720 derivative OSU-2S with potent cytotoxicity against leukemic B cells. OSU-2S induces activation of protein phosphatase 2A (PP2A), phosphorylation and nuclear translocation of SHP1(S591) and deregulation of multiple cellular processes in chronic lymphocytic leukemia (CLL) resulting in potent cytotoxicity. To preclude OSU-2S-mediated effects on these ubiquitous phosphatases in unintended cells and avoid potential adverse effects, we developed an OSU-2S-targeted delivery of immunonanoparticles (2A2-OSU-2S-ILP), that mediated selective cytotoxicity of CLL but not normal B cells through targeting receptor tyrosine kinase ROR1 expressed in leukemic but not normal B cells. Developing a novel spontaneous CLL mouse model expressing human ROR1 (hROR1) in all leukemic B cells, we demonstrate the therapeutic benefit of enhanced survival with 2A2-OSU-2S-ILP in vivo. The newly developed non-immunosuppressive OSU-2S, its delivery using human CLL directed immunonanoparticles and the novel transgenic (Tg) mouse model of CLL that expresses hROR1 exclusively in leukemic B cell surface are highly innovative and can be applied to CLL and other ROR1+ malignancies including mantle cell lymphoma and acute lymphoblastic leukemia.

Methods for the generation of chicken monoclonal antibody fragments by phage display.

Phage display has become an important approach for the preparation of monoclonal antibodies from both immune and nonimmune sources. This approach allows for the rapid selection of monoclonal antibodies without the restraints of the conventional hybridoma approach. Although antibodies to a wide variety of antigens have been selected using phage display, some highly conserved mammalian antigens have proven to be less immunogenic in mammalian animals commonly used for immunization. In order to optimize methods for constructing chicken immunoglobulin phage display libraries in the pComb3 system, we have immunized chickens with the hapten fluorescein, and generated combinatorial antibody libraries from spleen and bone marrow RNA. Herein we present methods for the isolation of scFv, diabody and Fab fragment libraries from chickens. Chicken Fab fragment libraries are constructed using human constant regions, facilitating detection with readily available reagents as well as humanization. Analysis of the selected V-genes revealed that gene conversion events were more extensive in light-chain variable region genes as compared to heavy-chain variable region genes. In addition, we present a new variant of the pComb3 phage display vector system.

[Anomalous course and anomalous division of the median nerve in the distal forearm]. / Ungewöhnlicher Verlauf und ungewöhnliche Teilung des N. medianus am distalen Unterarm.

An anatomic variation of the median nerve is demonstrated in a female patient suffering from carpal tunnel syndrome subsequent to a distal radius fracture with malalignment and reflex sympathetic dystrophy. The median nerve coursed anterior to the superficial flexor tendons from proximal ulnar toward the distal radial region of the distal forearm, giving off an ulnar branch just 2.5 cm proximal to the flexor retinaculum. This case proves that in the distal forearm, branches of the median nerve can be found both radial and ulnar to the midline.

[TNF-alpha secretion by human macrophage-like cells in response to wear particles and its modification by drugs]. / TNF alpha-Sekretion durch Abriebpartikel im humanen Makrophagenmodell und deren Modulation durch Medikamente.

UNLABELLED: Tumour necrosis factor (TNF) is considered to be the initiator protein of particle disease leading to aseptic loosening of endoprostheses. The aim of the present study was to investigate the TNF response of the macrophage-like cells (MLC) to the periprosthetic particles typically found during revision surgery. For this purpose, particles of polyethylene (PE), pure titanium (Ti), chromium (Cr), cobalt (Co), alumina ceramic (Al2O3) and zirconium dioxide (ZrO2) were used. Additionally, the therapeutic effect of non-steroidal and steroidal drugs, biphosphonates and pentoxyfylline on PE particles was investigated with the aim of differentiating drugs with, from those without, a positive effect on aseptic loosening. METHOD: In an established macrophage model (Rader et al. 1999), THP1 cells (human monocytic cell line) were differentiated over a period of five days in the presence of vitamin D3 and GM-CSF in macrophage-like cells (MLC). To obtain a TNF profile of the different materials, 10(6) MLC were incubated with each of a range of different particle concentrations. For drug testing purposes 80 x 10(8) PE particles, which evoked a maximum TNF response, were applied together with increasing drug concentrations in the same manner. The supernatant was then investigated for TNF secretion using ELISA. RESULTS: It was found that the greatest TNF response was provoked by Co and PE particles, and was 25 and 23 times as high, respectively, in comparison with control. The smallest TNF secretion was seen with Al2O3 (4 x control) and ZrO2 (5 x control). At the recommended dose, non-steroidal anti-inflammatory drugs (NSAIDs) produced no decrease in TNF secretion. The biphosphonates, etidronate and ibendronate significantly reduced the TNF response of the PE-stimulated macrophages (by 1/7 and 1/5, respectively). Therapeutic doses of pentoxyfylline also led to a decrease of 1/5 in maximum TNF release. CONCLUSION: Ceramic articulating surfaces are superior to metal/metal or PE/PE matings in terms of the biological effects of their wear particles. At therapeutic doses, NSAIDs have no beneficial effect on the process of aseptic loosening. Certain biphosphonates and pentoxyfylline have a positive effect on aseptic loosening.

[Standardized testing of bone implant surfaces with an osteoblast cell culture cyste. III. PVD hard coatings and Ti6Al4V]. / Standardisierte Testung von Skelett-Implantatoberflächen mit einem Osteoblasten-Zellkultursystem. III. PVD-Hartstoffbeschichtungen und Ti6Al4V.

The effect of titanium-based PVD coatings and a titanium alloy on the proliferation and differentiation of osteoblasts was investigated using a standardised cell culture system. Human fetal osteoblasts (hFOB 1.19) were cultured on titanium-niobium-nitride ([Ti,Nb]N), titanium-niobium-oxy-nitride coatings ([Ti,Nb]ON) and titanium-aluminium-vanadium alloy (Ti6Al4V) for 17 days. Cell culture polystyrene (PS) was used as reference. For the assessment of proliferation, the numbers and viability of the cells were determined, while alkaline phosphatase activity, collagen I and osteocalcin synthesis served as differentiation parameters. On the basis of the cell culture experiments, a cytotoxic effect of the materials can be excluded. In comparison with the other test surfaces, [Ti,Nb]N showed greater cell proliferation. The [Ti,Nb]N coating was associated with the highest level of osteocalcin production, while all other differentiation parameters were identical on all three surfaces. The test system described reveals the influence of PVD coatings on the osteoblast differentiation cycle. The higher oxygen content of the [Ti,Nb]ON surface does not appear to have any positive impact on cell proliferation. The excellent biocompatibility of the PVD coatings is confirmed by in vivo findings. The possible use of these materials in the fields of osteosynthesis and articular surfaces is still under discussion.

[Standardized tests of bone implant surfaces with an osteoblast cell culture system. I. Orthopedic standard materials]. / Standardisiertes Testen von Skelett-Implantatoberflächen mit einem Osteoblasten-Zellkultursystem. I. Orthopädische Standardmaterialien.

The effect of standard orthopaedic materials on proliferation and differentiation of osteoblasts was examined using a standardised cell culture system. Osteoblasts hFOB 1.19 were cultured on stainless steel (SS), a chromium-cobalt-molybdenum alloy (CrCoMb) and commercially pure titanium (cpTi) for 12 days. Cell culture polystyrene (PS) was used as a reference. Cell numbers and cell viability were used as parameters of proliferation. Cell differentiation was assessed using alkaline phosphatase activity, collagen I and osteocalcin production. The parameters of proliferation showed earlier maximum values on PS and cpTi, while proliferation was delayed on SS and CrCoMb. The highest values of differentiation were found on cpTi. The development of alkaline phosphatase activity showed two peaks reflecting apoptosis and redifferentiation. The cell culture system hFOB 1.19 is thus suitable for revealing differences in proliferation and differentiation of osteoblasts on standard orthopaedic materials. The results correlate with previous in vivo findings. Using this system, the dynamic effect of the material surface on the differentiation process of osteoblasts can be demonstrated.

[Standardized testing of bone implant surfaces with an osteoblast cell culture system. II. Titanium surfaces of different degrees of roughness]. / Standardisiertes Testen von Skelett-Implantatoberflächen mit einem Osteoblasten-Zellkultursystem. II. Titanoberflächen unterschiedlicher Rauhigkeit.

The effect of titanium surfaces with different degrees of roughness on osteoblast proliferation and differentiation was investigated using a standardised cell culture system. Human foetal osteoblasts (hFOB 1.19) were cultured on polished (Ti pol), sandblasted (Ti sb) and sandblasted/heat treated (Ti sb-ht) titanium surfaces for 17 days. Cell culture quality polystyrene (Ps) was used as a control. Cell number and viability were determined for assessment of proliferation. Alkaline phosphatase activity, collagen I and osteocalcin production were measured as parameters for osteoblast differentiation. In the early phase, higher proliferation values were measured on Ti pol. However, on Ti sb and Ti sb-ht higher proliferation was found in the late phase. The activity of the early differentiation marker alkaline phosphatase was higher on Ti pol. No differences were seen for the late differentiation parameters collagen I and osteocalcin. The test system permits the influence of the surface structure on the dynamics of the osteoblast development cycle to be determined. The larger surface area of rough materials leads to an initially delayed, but then prolonged cell proliferation. This model correlates with recent in vivo findings, and confirms the use of rough surfaces for implants in direct contact with bone, even at the cellular level.

[Cytotoxicity study of high gold content Degutan surfaces of various degrees of roughness with fibroblasts (BALB 3T3) and osteoblasts (hFOB 1.19)]. / Zytotoxizitätsuntersuchung von hochgoldhaltigen Degutan-Oberflächen unterschiedlicher Rauhigkeit mit Fibroblasten (BALB 3T3) und Osteoblasten (hFOB 1.19).

The cytotoxicity of Degutan surfaces with different degrees of roughness, and the effect of surface structures on osteoblast proliferation and differentiation, was investigated with standardised cell culture systems. Fibroblast cell lines (BALB/3T3) and osteoblast cell lines (hFOB 1.19) were used. The number and variability of the cells were determined for assessment of proliferation and alkaline phosphatase activity, collagen I and osteocalcin production were used as parameters for differentiation. In the early phase, the largest numbers of cells and greatest proliferation were measured on polished Degutan surfaces. In the late phase, however, larger numbers of cells and a greater degree of proliferation were to be seen on sandblasted and sandblasted/heat-treated Degutan surfaces. No differences were found for collagen I, osteocalcin production or alkaline phosphatase activity. Neither the osteoblasts nor the fibroblasts revealed a toxic effect of Degutan. The results for osteoblast differentiation correlate with recent studies on identical structured titanium surfaces. In view of the immeasurable amount of ion release, Degutan may be considered an ideal model for an inert material surface.