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1.
J Biomed Mater Res B Appl Biomater ; 107(4): 1246-1253, 2019 05.
Article in English | MEDLINE | ID: mdl-30261124

ABSTRACT

Total joint replacement is one of the most successful procedures in orthopedic surgery today. However, metal implant materials undergo wear and corrosion processes. Generated particles and ions can cause a variety of cellular reactions. Cobalt-containing alloys are used frequently in implant materials. Some studies suggest that cobalt exhibits potential cytotoxic effects, for example, via generation of reactive oxygen species (ROS). To further elucidate the effects of cobalt on human cells, we determined cell viability and cytosolic and mitochondrial superoxide formation after incubation of either ions or particles with different cells. MM-6 and Jurkat cell lines were treated for 24, 48 and 72 h with either CoCrMo particles or cobalt ions (supplied as CoCl2 ). A total of 24 h exposure of both forms of cobalt did not induce cell death using terminal deoxynucleotidyl transferase (TUNEL) and trypan blue assay. Interestingly, the formation of superoxide (O2.- ) is evoked mainly by ionic CoCl2 but not cobalt particles. Cobalt alloy particles are likely to even suppress O2.- formation in mitochondria in both used cell lines. Furthermore, we did not observe any effect of cobalt particles on O2.- formation in peripheral blood mononuclear cells (PBMCs) from healthy donors. We also found that the O2- formation by CoCl2 within mitochondria is a generalized effect for all cell types used, while the formation of superoxide in cytosolic compartment is cell-type dependent. In summary, our data suggest that cobalt ions specifically induce the formation of O2.- , whereas the cobalt particles were better tolerated. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1246-1253, 2019.


Subject(s)
Alloys/pharmacology , Arthroplasty, Replacement, Hip , Cobalt/pharmacology , Hip Prosthesis , Leukocytes, Mononuclear/immunology , Superoxides/immunology , Humans , Jurkat Cells
2.
J Biomed Mater Res A ; 104(1): 136-44, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26255872

ABSTRACT

In this work, we characterize integrin CD11c (αXß2) expression in periprosthetic tissues of 45 hip revisions. Tissues were retrieved from 23 ceramic-on-ultra-high molecular weight polyethylene (UHMWPE), 20 metal-on-UHMWPE, and 2 metal-on-metal total hip arthroplasties (THAs). Capsular tissue retrieved during primary THA from 19 patients served as controls. We identified a system to identify important immunohistochemical markers that are expressed in aseptic loosening. We focused on CD11c, CD68 and CD14. We observed that the CD11c molecule possesses four different cellular patterns in the periprosthetic tissues. Three of them are associated with the occurrence of UHMWPE abrasive material. Double staining with CD14 and CD68 was used for a more detailed analysis of the CD11c expressing cells. We observed that all forms of CD11c positive cells are CD68 positive however, only two forms of CD11c expressing cells are positive for CD14. Providing cellular diversity of CD11c expression in periprosthetic tissue, our results provide a contribution toward the further understanding of different cellular mechanisms to foreign body material.


Subject(s)
Arthroplasty, Replacement, Hip , CD11c Antigen/metabolism , Prosthesis Failure , Adult , Aged , Aged, 80 and over , Antigens, CD/metabolism , Antigens, Differentiation, Myelomonocytic/metabolism , Arthroplasty, Replacement, Hip/adverse effects , Female , Humans , Immunohistochemistry , Lipopolysaccharide Receptors/metabolism , Male , Metals/adverse effects , Middle Aged , Prosthesis-Related Infections/etiology
3.
J Biomed Mater Res A ; 101(11): 3320-6, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23529961

ABSTRACT

Large-diameter metal-on-metal (MoM) bearings evolved from the success of hip resurfacing. These implants were used in revision surgery in cases with well-fixed acetabular cups but loose or failed femoral stems, to avoid cup revision. Early data showed low rates of dislocation and potentially low wear profiles due to better fluid film lubrication. The risk of impingement was also thought to be low due to the increased head-neck ratio. Subsequently large-diameter MoM heads gained popularity in primary hip replacement. Recent data has emerged on the unacceptably high revision rates among patients with large-diameter MoM total hip arthroplasties (THAs), high blood levels of metal ions, and adverse tissue reactions. The head-neck (cone-taper) modular interface probably represents the weak link in large metal heads that have been used on conventional tapers. Increased torque of the large head, micromotion, and instability at the cone-taper interface, synergistic interactions between corrosion and wear, edge loading, low clearance, and psoas impingement are the likely causes for early failure of these prostheses.


Subject(s)
Arthroplasty, Replacement, Hip/adverse effects , Metal-on-Metal Joint Prostheses/adverse effects , Orthopedics/history , Prosthesis Design , History, 20th Century , Humans , Ions , Prosthesis Failure
4.
Clin Orthop Relat Res ; 470(11): 3101-8, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22864616

ABSTRACT

BACKGROUND: Metal-on-metal (MoM) THAs have reduced wear rates compared with metal-on-polyethylene. However, elevated serum metal ion levels and pseudotumors have been reported in large MoM articulations. QUESTIONS/PURPOSES: We therefore determined (1) if corrosion occurred at the cone/taper interface leading to instability in patients with large-diameter THAs; (2) how patients presented clinically and radiographically; (3) if adverse periprosthetic tissue reactions occurred; (4) whether metal was released from the implants into the periprosthetic tissues; and (5) if head size correlated with metal release. METHODS: We reviewed 114 patients who had revisions of large-diameter head MoM articulations. Mean time of implantation was 46 months. To identify adverse reactions and particle load, tissues were stained by hematoxylin and eosin and CD3/CD20/CD68 antibodies. Periprosthetic tissues were analyzed for metal content and distribution in different regions. Electrochemical reactions between the stem and adapter were investigated by a minicell electrode. RESULTS: Electrochemical studies on the stem and the head adapter showed a risk for galvanic corrosion. Ninety-four percent of patients had instability at the cone/taper interface. All patients presented with early clinical symptoms; 59 patients had radiographic signs of loosening. One hundred four patients had foreign body reactions and necrosis. The largest amounts of metal released were titanium or iron. We found no correlation between head size and metal ion release. CONCLUSIONS: These findings suggest that in modular cone/taper connections, friction of the MoM articulations may cause failure of the cone/taper interface leading to galvanic corrosion and loosening. It is unclear whether the design of this MoM system provides sufficient stability at the taper.


Subject(s)
Biocompatible Materials , Hip Prosthesis/adverse effects , Joint Instability/etiology , Metals , Prosthesis Failure , Adult , Aged , Aged, 80 and over , Arthroplasty, Replacement, Hip , Female , Hip Joint/diagnostic imaging , Humans , Joint Instability/surgery , Male , Metals/adverse effects , Metals/analysis , Middle Aged , Radiography , Retrospective Studies
5.
PLoS One ; 7(3): e31391, 2012.
Article in English | MEDLINE | ID: mdl-22412835

ABSTRACT

Efficient adaptive immune responses require the localization of T lymphocytes in secondary lymphoid organs and inflamed tissues. To achieve correct localization of T lymphocytes, the migration of these cells is initiated and directed by adhesion molecules and chemokines. It has recently been shown that the inhibitory surface molecule CD152 (CTLA-4) initiates Th cell migration, but the molecular mechanism underlying this effect remains to be elucidated. Using CD4 T lymphocytes derived from OVA-specific TCR transgenic CD152-deficient and CD152-competent mice, we demonstrate that chemokine-triggered signal transduction is differentially regulated by CD152 via phosphoinositide 3-kinase (PI3K)-dependent activation of protein kinase B (PKB/Akt). In the presence of CD152 signaling, the chemoattractant CCL4 selectively induces the full activation of Akt via phosphorylation at threonine 308 and serine 473 in pro-inflammatory Th lymphocytes expressing the cognate chemokine receptor CCR5. Akt signals lead to cytoskeleton rearrangements, which are indispensable for migration. Therefore, this novel Akt-modulating function of CD152 signals affecting T cell migration demonstrates that boosting CD152 or its down-stream signal transduction could aid therapies aimed at sensitizing T lymphocytes for optimal migration, thus contributing to a precise and effective immune response.


Subject(s)
CTLA-4 Antigen/metabolism , Chemotaxis, Leukocyte/immunology , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction , Th1 Cells/enzymology , Th1 Cells/immunology , Animals , CTLA-4 Antigen/genetics , Enzyme Activation/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Receptors, CCR/metabolism , Receptors, CCR5/metabolism , T-Lymphocytes/immunology , T-Lymphocytes/metabolism
6.
Int J Legal Med ; 122(1): 67-71, 2008 Jan.
Article in English | MEDLINE | ID: mdl-17273877

ABSTRACT

Intron 40 of the von Willebrand factor (vWF) gene exhibits a highly variable region of about 0.65 kb, which contains 5 juxtaposed STRs. We sequenced 0.65 kb amplicons from 68 chromosomes and found 2 frequent indel polymorphisms and 5 SNPs. The 68 chromosomes investigated here presented a total of 47 different haplotypes. Regarding the SNP allele distribution in our sample, we arranged our results of the vWF intron 40 into a system of 3 haplotypes, i.e. haplotypes a, b and c. Our review may be valuable in further optimising vWF typing in forensic applications and in avoiding pitfalls. Further attempts to develop sophisticated techniques may soon enable haplotyping using autosomale STR clusters.


Subject(s)
Introns/genetics , Polymorphism, Genetic , von Willebrand Factor/genetics , Haplotypes , Humans , Polymerase Chain Reaction , Sequence Analysis, DNA , Tandem Repeat Sequences
7.
Pathol Res Pract ; 203(4): 245-9, 2007.
Article in English | MEDLINE | ID: mdl-17317032

ABSTRACT

Expression of the transforming growth factor-beta (TGF-beta) protein family in the peripheral nervous system is well established, but the role of their cognate receptors TGF-beta receptor type 1 (R1) and type 2 (R2) has been less well studied. TGF-beta plays an essential role in Schwann cell proliferation and differentiation, and is involved in neurotrophic effects of several neurotrophic substances. TGF-beta is also expressed in benign peripheral nervous system tumors such as vestibular schwannomas. In the present study, we aimed to detect TGF-beta R1 and R2 in a total of 40 sporadic vestibular schwannomas using immunohistochemistry, and correlated the findings to essential clinicopathologic data. TGF-beta, TGF-beta R1, and TGF-beta R2 mRNA was further analyzed by RT-PCR in six vestibular schwannomas. TGF-beta R1 immunoexpression was found in about 95% of the tumors. TGF-beta R1 was equally present in Antoni A and Antoni B areas of the tumors. TGF-beta R2 was found immunohistochemically in 77%. In addition, all tumors showed strong expression of TGF-beta. No correlation between TGF-beta R1 or R2 expression and clinicopathologic parameters such as age, sex, clinical symptoms, growth pattern, and proliferation acitivity as measured by Ki-67 (MIB-1) staining was found. Moreover, all schwannomas studied contained TGF-beta, TGF-beta R1, and TGF-beta R2 mRNA. Therefore, the TGF-beta/TGF-beta R1 and -R2 system is present in human schwannomas, but its biologic role for tumor development and growth remains unclear.


Subject(s)
Cranial Nerve Neoplasms/metabolism , Neurilemmoma/metabolism , Receptors, Transforming Growth Factor beta/biosynthesis , Vestibulocochlear Nerve Diseases/metabolism , Cranial Nerve Neoplasms/pathology , Humans , Immunohistochemistry , Neurilemmoma/pathology , RNA, Messenger/analysis , Reverse Transcriptase Polymerase Chain Reaction , Vestibulocochlear Nerve Diseases/pathology
8.
Biochem Biophys Res Commun ; 331(1): 86-92, 2005 May 27.
Article in English | MEDLINE | ID: mdl-15845362

ABSTRACT

The reasons for overexpression of the oncogene pituitary tumor transforming gene (PTTG) in tumors are still not fully understood. A possible influence of the insulin-like growth factor I (Igf-I) may be of interest, since enhanced Igf-I signalling was reported in various human tumors. We examined the influence of Igf-I and insulin on PTTG expression in human astrocytoma cells in comparison to proliferating non-neoplastic rat embryonal astrocytes. PTTG mRNA expression and protein levels were increased in malignant astrocytes treated with Igf-I or insulin, whereas in rat embryonic astrocytes PTTG expression and protein levels increased only when cells were exposed to Igf-I. Enhanced transcription did not occur after treatment with inhibitors of phosphoinositol-3-kinase (PI3K) and mitogen-activated protein kinase (MAPK), blocking the two basic signalling pathways of Igf-I and insulin. In addition to this transcriptional regulation, both kinases directly bind to PTTG, suggesting a second regulatory route by phosphorylation. However, the interaction of endogenous PTTG with MAPK and PI3K, as well as PTTG phosphorylation were independent from Igf-I or insulin. The latter results were also found in human testis, which contains high PTTG levels as well as in nonneoplastic astrocytes. This suggest, that PI3K and MAPK signalling is involved in PTTG regulation not only in malignant astrocytomas but also in non-tumorous cells.


Subject(s)
Astrocytes/metabolism , Astrocytoma/metabolism , Insulin-Like Growth Factor I/pharmacology , Insulin/pharmacology , Neoplasm Proteins/biosynthesis , Up-Regulation , Animals , Astrocytes/enzymology , Astrocytoma/enzymology , Astrocytoma/genetics , Cell Line, Tumor , Cells, Cultured , Enzyme Inhibitors/pharmacology , Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors , Extracellular Signal-Regulated MAP Kinases/metabolism , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Phosphoinositide-3 Kinase Inhibitors , RNA, Messenger/biosynthesis , Rats , Securin , Serine/metabolism
9.
J Neurochem ; 80(1): 149-57, 2002 Jan.
Article in English | MEDLINE | ID: mdl-11796753

ABSTRACT

The second beta-like subunit (SBD) is a putative structural subunit of Drosophila melanogaster nicotinic acetylcholine receptors (nAChRs). Here we have produced specific antibodies against SBD to study, which other nAChR subunits can co-assemble with SBD in receptor complexes of the Drosophila nervous system. Immunohistochemical studies in the adult optic lobe revealed that SBD has a distribution similar to that of the alpha-subunit ALS in the synaptic neuropil. The subunits ALS, D(alpha)2 and SBD can be co-purified by alpha-bungarotoxin affinity chromatography. Moreover, anti-SBD antibodies co-precipitate ALS and D(alpha)2 and, vice versa, ALS and D(alpha)2 antibodies co-immunoprecipitate SBD protein. Two-step immunoaffinity chromatography with immobilized antibodies against ALS and D(alpha)2 revealed the existence of nAChR complexes that include ALS, D(alpha)2 and SBD as integral components. Interestingly, the genes encoding these three subunits appear to be directly linked in the Drosophila genome at region 96 A of the third chromosome. In addition, SBD appears to be a component of a different receptor complex, which includes the ARD protein as an additional beta-subunit, but neither ALS nor D(alpha)2 nor the third alpha-subunit D(alpha)3. These findings suggest a considerable complexity of the Drosophila nicotinic receptor system.


Subject(s)
Drosophila melanogaster/genetics , Drosophila melanogaster/metabolism , Genetic Linkage , Receptor Aggregation/physiology , Receptors, Nicotinic/genetics , Receptors, Nicotinic/physiology , Animals , Chromatography, Affinity , Genome , Immunologic Techniques , Precipitin Tests , Protein Isoforms/genetics , Protein Isoforms/physiology
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