Background There is mounting evidence to suggest the involvement of the immune system by means of activation by metal ions released via biocorrosion, in the pathophysiologic mechanisms of aseptic loosening of orthopedic implants. However, the detailed mechanisms of how metal ions become antigenic and are presented to T-lymphocytes, in addition to how the local inflammatory response is driven, remain to be investigated. Methods Human T-lymphocytes were cultured in the presence of a variety of metal ions before investigating functional and phenotypic changes using flow cytometric analysis. Additionally, human monocyte-derived dendritic cells (mDC) loaded with metal ions were used as antigen-presenting cells and incubated with naive T-lymphocytes with the aim of generating titanium-specific T-lymphocytes. Results Using an autologous in vitro model, with mDC treated with Titanium (IV), we were able to induce Titanium (IV)-specific T-lymphocytes. These T-lymphocytes responded in a dose-related manner to Titanium (IV), while they did not cross-react with Titanium (III) or other metal ions, indicating that the new antigenic peptide complexes formed by Titanium (IV) are highly specific. Conclusion This study showed that mDC exposed to Titanium (IV) are able to induce the generation of Titanium (IV)-specific T-lymphocytes, demonstrating the strong and specific antigenicity of Titanium (IV) ions released by biocorrosion.

Metal implants have become essential thera- peutic tools in cranial, dental, orthopaedic and cardiovascular surgery. In most cases, the implants are well tolerated. How- ever, short term orthopaedic implant loosening and failure happens in 3-80% of patients, depending on implant material, location and precondition. Especially inflamed tissues like rheumatoid arthritic joints have been shown to have increased implant failure. However, the mechanisms of implant loosen- ing are still not well understood. This study investigated cellu- lar and immune-related mechanisms that may play a role in aseptic implant loosening. A human in vitro model has been used for this study. The interaction between metal surfaces or metal ions and immune cells or bone cells was investigated. Cell culture, immune fluo- rescence and electron microscopy, functional tests, flow cy- tometry and molecular methods were applied. The results indicate that metal surfaces made of stainless steel, aluminum or titanium are corroded by human osteo- clasts (bone resorbing cells) in vitro. The released ions are taken up by the osteoclasts and immune cells, which are af- fected in various ways, including induction of metal sensitivity reactions and enhanced activation of osteoclasts. We can conclude that human osteoclasts are able to corrode metal implants and release metal ions, which have then various effects on immune cells and possible on different organs and the whole organism.

Background: Severe brain trauma leads to an activation of the immune system. To this date, neither the exact perturbation of the specific immune reaction induced by the traumatic brain injury (TBI), nor the interactions leading to the infiltration of peripheral immune cells into the brain are fully understood.Patients and methods: Serum was collected from 17 patients with TBI and a long bone fracture, 24 patients with an isolated long bone fracture and from healthy individuals. The effect of the serum on normal human monocytes and T-lymphocytes was tested in vitro by assessing proliferation and expression of surface markers, chemokine receptors and cytokines.Results: Serum collected from patients with a TBI and a long bone fracture increased the expression of the chemokine receptor CCR4 in monocytes when compared to patients with an isolated long bone fracture. Extending this comparison to T-lymphocytes, the serum from TBI patients induced lower proliferation rates and decreased expression of the pro-inflammatory cytokine TNF-alpha, while simultaneously increasing the secretion of immune-modulatory cytokines (IL-4, IL-10 and TGF-beta) (p < 0.05).Conclusion: Patients with a TBI release currently unknown soluble factors into the circulating blood that up regulate expression of chemokine receptor CCR4 in peripheral blood monocytes whilst concurrently inducing expression of immunosuppressive cytokines by activated T-lymphocytes. (C) 2009 Elsevier Ltd. All rights reserved.

We adapt the cognitively-oriented morphology acquisition model proposed in (Chan 2008) to perform morphological analysis, extending its concept of base-derived relationships to allow multi-step derivations and adding features required for robustness on noisy corpora. This results in a rule-based morphological analyzer which attains an F-score of 58.48% in English and 33.61% in German in the Morpho Challenge 2009 Competition 1 evaluation. The learner’s performance shows that acquisition models can effectively be used in text-processing tasks traditionally dominated by statistical approaches.

Vanadium is a heavy metal that has no known biological role in humans. However, increasing exposure through advances in medical applications – orthodontic/orthopedic metal implants, vanadium-containing drugs and environmental exposure have raised questions on the influence of vanadium on the immune system. As initiators of the adaptive immune response, dendritic cells (DC) are responsible for the differentiation of effector T-lymphocytes and the resulting immune reactivity. This study assessed the differences in immune reactivity towards various vanadium compounds and investigated the influence of vanadium (III), (IV), and (V) ions on peripheral blood monocytes (PBMC) and DC. Exposure to vanadium (III) and (IV) concentrations above 125 µM reduced the proliferation of lymphocytes. Mitochondrial DC activity was reduced in the presence of low concentrations of vanadium. Flow cytometry analysis of cell surface molecules showed slight alterations of MHC class II (antigen presenting molecule) and reduction of CD54 (adhesion molecule) with increasing vanadium concentrations. Secreted cytokines and chemokines produced by DC were measured through a cytometric bead assay, which showed no significant difference after exposure to various vanadium ions. Finally, the ability of vanadium-treated DC to interact with lymphocytes was measured through proliferation of allogenic non-adherent PBMC and showed retention of proliferative capacity. These results indicate that vanadium exerts a weak influence on the maturation and function of DC, which suggests that alterations in immune reactivity by vanadium is mediated directly on effector lymphocytes.

We develop an unsupervised algorithm for morphological acquisition to investigate the relationship between linguistic representation, data statistics, and learning algorithms. We model the phenomenon that children acquire the morphological inflections of a language monotonically by introducing an algorithm that uses a bootstrapped, frequency-driven learning procedure to acquire rules monotonically. The algorithm learns a morphological grammar in terms of a Base and Transforms representation, a simple rule-based model of morphology. When tested on corpora of child-directed speech in English from CHILDES (MacWhinney in The CHILDES-Project: Tools for analyzing talk. Erlbaum, Hillsdale, 2000 ), the algorithm learns the most salient rules of English morphology and the order of acquisition is similar to that of children as observed by Brown (A first language: the early stages. Harvard University Press, Cambridge, 1973 ). Investigations of statistical distributions in corpora reveal that the algorithm is able to acquire morphological grammars due to its exploitation of Zipfian distributions in morphology through type-frequency statistics. These investigations suggest that the computation and frequency-driven selection of discrete morphological rules may be important factors in children’s acquisition of basic inflectional morphological systems.

The Asymmetric Threat Response and Analysis Program (ATRAP) is a software system for intelligence fusion, visualization, reasoning, and prediction. ATRAP consists of a set of tools for annotating and automatically extracting entities and relationships from documents, visualizing this information in relational, geographic, and temporal dimensions, and determining future courses of action of adversaries by creating situational threat templates and applying customized prediction algorithms. In this paper, we first describe the task of analyzing data in intelligence reports, and then provide an overview of major system components: the Text Highlighter tool, the ThoughtSpace™ visualization environment, and the Template Builder and prediction tool. Subsequently, we describe linguistic characteristics of intelligence reports, and describe ATRAP's named entity recognition system.

There is increasing evidence that titanium ions are released from orthopedic implants by biocorrosion. The aim of this study was to investigate titanium uptake by human T‐lymphocytes and its effects on phenotype and proliferation. Freshly isolated human nonadherent peripheral blood mononuclear cells (NA‐PBMC), were exposed to TiCl4 [Ti(IV)]. Bioavailability and distribution of Ti(IV) in T‐lymphocytes was determined by energy‐filtered electron microscopy (EFTEM). The effects of Ti(IV) challenge on nonactivated and PHA‐activated cells were assessed by flow cytometric analysis of surface markers, RANK‐L production, and proliferation assays. EFTEM colocalized Ti(IV) with phosphorus in the nucleus, ribosomes, cytoplasmic membranes, and the surface membrane of T‐lymphocytes. Ti(IV) increased significantly the expression of CD69, CCR4, and RANK‐L in a concentration‐dependent manner. Titanium enters T‐lymphocytes through a currently unknown mechanism and binds to phosphorus‐rich cell structures. Titanium influences phenotype and function of T‐lymphocytes, resulting in activation of a CD69+ and CCR4+ T‐lymphocyte population and secretion of RANK‐L. These results strongly suggest the involvement of titanium ions challenged T‐lymphocytes in the complex pathophysiological mechanisms of aseptic loosening of orthopedic implants. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:341–347, 2010

Cadosch, Dieter MD, PhDc; Sutanto, Michael; Chan, Erwin; Gautschi, Oliver P.; Decurtins, Marco; Simmen, Hans-Peter; Filgueira, Luis Author Information

Orthopaedic metal implants composed of titanium are routinely used in bone fracture repair and for joint replacement therapies. A considerable fraction of implant recipients are unable to benefit due to implant failure resulting from aseptic loosening, while others may experience cutaneous sensitivity to titanium after implantation. An adaptive immune reactivity towards titanium ions, originating from the biocorrosion of the implants, could play a role. As an initiator of the adaptive immune response, dendritic cells (DC) were studied for uptake and characteristics after titanium exposure. Energy filtered transmission electron microscopy showed uptake of titanium(iv) (Ti(iv)) ions by DCsin vitro and co-localisation with phosphorus-rich cell structures of the DC membranes (phospholipids), cytoplasm (ribosomes and phosphorylated proteins) and the nucleus (DNA). DC maturation and function were investigated by measuring cell surface marker expression by flow cytometry. After exposure, DCs showed a decrease in MHC class II (HLA-DR), co-stimulatory molecules (CD40, CD80 & CD86) and chemokine receptors (CCR) 6 and CCR7 but an increase in CCR4 after Ti(iv) treatment. However, Ti(iv) treated DCs had an increased stimulatory capacity towards allogenic lymphocytes. A Ti(iv) concentration dependant increase of IL-12p70 was observed amidst decrease of the other measured cytokines (TGF-β1 and TGF-β2). Hence, Ti(iv) alters DC properties, resulting in an enhanced T lymphocyte reactivity and deviation towards a Th1 type immune response. This effect may be responsible for the inflammatory side effects of titanium implants seen in patients.

There is increasing evidence that titanium (Ti) ions are released from orthopedic implants, with concentrations in the range of 1 microM in tissue and blood, and may play a role in aseptic loosening of orthopedic implants. This study investigated whether Ti(IV) ions induce differentiation of monocytic osteoclast precursors into osteo-resorptive multinucleated cells and influence the activation and function of in vitro generated osteoclasts. Human monocytes and in vitro generated osteoclasts were exposed to 1 microM Ti(IV) ions for 10 days. Thereafter, osteoclast differentiation, activation, and function were evaluated. Transcription of specific osteoclastic genes was measured using quantitative reverse transcription polymerase chain reactions, which showed increased expression of tartrate-resistant acid phosphatase (TRAP) in approximately 20% of Ti(IV)-treated monocytes. Detection and quantification of intracellular TRAP activity using ELF97 as a fluorescent substrate revealed a significant increase of TRAP-positive cells in Ti(IV)-treated monocytes. Additionally, as demonstrated on dentin slide cultures, Ti(IV)-treated monocytes became functional bone resorbing cells, significantly increasing their osteo-resorptive activity to similar levels as osteoclasts in vitro. These results suggest that Ti(IV) ions released by biocorrosion from orthopedic implants induce differentiation of monocytes toward mature, functional osteoclasts, which may well contribute the pathomechanism of aseptic loosening.

There is increasing evidence that titanium (Ti(IV)) ions are released from orthopedic implants and play a role in aseptic loosening. This study aimed to investigate whether titanium induces expression of chemokines and cytokines that are important in osteoclastogenesis in human osteoclasts and osteoblasts. Incubation of those cells with 1 muM Ti(IV) significantly upregulated expression of CCL17/TARC and CCL22/MDC, RANK-L, M-CSF and pro-inflammatory cytokines as determined by quantitative real-time PCR and ELISA assays. Additionally, flow cytometry was used to show Ti(IV) related increased expression of CCR4, the cognate receptor for CCL17 and CCL22 in challenged osteoclast precursors. These results strongly suggest that Ti(IV) ions play a role in the recruitment of osteoclast precursors to the bone-implant interface by increasing CCL17 and CCL22 expression and by upregulating their cognate receptor. Moreover the increased expression of RANK-L and M-CSF by osteoblasts together with increased levels of pro-inflammatory cytokines may enhance osteoclast differentiation and activity, and subsequently contribute to the pathomechanism of aseptic loosening.

We use the Base and Transforms Model proposed by Chan [1] as the core of a morphological analyzer, extending its concept of base-derived relationships to allow multi-step derivations and adding a number of features required for robustness on larger corpora. The result is a rule-based morphological analyzer, attaining an F-score of 58.48% in English and 33.61% in German in the Morphochallenge 2009 Competition 1 evaluation.

Most metals in contact with biological systems undergo corrosion by an electrochemical process. This study investigated whether human osteoclasts (OC) are able to grow on stainless steel (SS) and directly corrode the metal alloy leading to the formation of corresponding metal ions, which may cause inflammatory reactions and activate the immune system. Scanning electron microscopy analysis demonstrated long-term viable OC cultures and evident resorption features on the surface of SS discs on which OC were cultured for 21 days. The findings were confirmed by atomic emission spectrometry investigations showing significantly increased levels of chromium, nickel, and manganese in the supernatant of OC cultures. Furthermore, significant levels of pro-inflammatory cytokines IL-1beta, IL-6, and TNF-alpha, which are considered to be major mediators of osteolysis, were revealed in the same cultures by cytometric bead array analysis. Within the present study, it was shown that human osteoclast precursors are able to grow and differentiate towards mature OC on SS. The mature cells are able to directly corrode the metal surface and release corresponding metal ions, which induce the secretion of pro-inflammatory cytokines that are known to enhance osteoclast differentiation, activation, and survival. Enhanced corrosion and the subsequently released metal ions may therefore result in enhanced osteolytic lesions in the peri-prosthetic bone, contributing to the aseptic loosening of the implant.

Metal implants are essential therapeutic tools for the treatment of bone fractures and joint replacements. The metals and metal alloys used in contemporary orthopedic and trauma surgery are well tolerated by the majority of patients. However, complications resulting from inflammatory and immune reactions to metal implants have been well documented. This review briefly discusses the different mechanisms of metal implant corrosion in the human body, which lead to the release of significant levels of metal ions into the peri-implant tissues and the systemic blood circulation. Additionally, this article reviews the effects of the released ions on bone metabolism and the immune system and discusses their involvement in the pathophysiological mechanisms of aseptic loosening and metal hypersensitivity in patients with metal implants.

Cadosch, Dieter MD, PhDc; Chan, Erwin PhDc; Gautschi, Oliver P. MD; Simmen, Hans-Peter MD; Filgueira, Luis MD Author Information

Titanium is increasingly used for implanted bio‐medical devices, including bone fracture treatment and joint replacement therapies. Bio‐corrosion of implants and accumulation of titanium in immune cells, lymph nodes and spleen has been reported. Inflammatory reactions against titanium implants have been reported in up to 15% of cases. However, little is known about the effect of titanium on immune cells. The aim of this study was to investigate the effect of Ti(IV) ions (1 to100μM) on human T‐lymphocytes, freshly isolated from buffy coats or peripheral venous blood of healthy individuals (n=10). No toxic effect was detected in viability assays for the applied titanium concentrations. Using energy filtered transmission electron microscopy, uptake and accumulation of titanium in T‐lymphocytes was documented. Titanium induced cell proliferation (BrdU incorporation assays) in a concentration dependent manner in 40% of the tested individuals. Cytokine measurement in the culture supernatants revealed increased IL‐6 and TNFα production at 12.5μM titanium concentration. Measurement of surface marker expression with flow cytometry showed increased expression of CD3, CD4, CD45 and the chemokine receptor CCR4.This study indicates that titanium affects human T‐lymphocytes by enhancing their inflammatory properties.