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Biomedical subjects

Eleftherios Tsiridis

Publications and source records attributed to Eleftherios Tsiridis.

At least 19 recordsLinked to original sources
PubMed2007

"Pseudosarcoma" in a pregnant woman.

BACKGROUND: Intravascular fasciitis (IVF) is a rare benign condition characterised by reactive myofibroblastic proliferation arising from the superficial or deep fascia and involving arteries and/or veins. It is a distinct variant of the more common condition of nodular fasciitis, which possesses similar clinical and histological features to IVF, but lacks vascular invasion. A thorough review of the literature revealed 26 reported cases of IVF. CASE PRESENTATION: We report a case of IVF in a 16-week pregnant lady affecting the hypothenar eminence of the hand associated with the ulnar artery. CONCLUSION: The characteristic involvement of muscular arteries and veins by reactive myofibroblastic proliferation in IVF suggests a malignant component and often leads to an inappropriate diagnosis for this benign condition. We propose that hormone-related changes associated with pregnancy may play an important role in the aetiopathogenesis of this myofibroblastic lesion.

Adult↗
PubMed2006

Transcriptomics and proteomics: advancing the understanding of genetic basis of fracture healing.

Fracture healing is a complex physiological post-natal process, which involves the coordination of several different cell types. Exploring the orchestration of events and the simultaneous activation of osteogenesis and chondrogenesis that recapitulates mammalian embryological skeletal development seems to be not only sophisticated but also challenging. A large number of genes involved in the above process are known, but many more remain to be discovered. The functional characterisation of these genes promises to elucidate the repair process as well as skeletal abnormalities and aging. We here review the current knowledge on early and late gene expression during fracture healing, the genes so far associated with osteoblast and osteoclast differentiation, the BMP antagonists, and the Wnts signalling pathway.

Bone Morphogenetic Proteins↗
PubMed2006

The role of inhibitory molecules in fracture healing.

The balance between all the signalling molecules involved in bone formation with their inhibitors and most importantly between BMPs and their antagonists is critical determinant of osteogenesis, and therefore of skeletal development, fracture repair, and bone remodelling. The main identified inhibitory molecules of the osteogenic lineage, either from studies during embryonic development or from in vitro and in vivo studies are presented in the herein study. Potential treatments using these molecules either alone or in combination with BMPs to control the bone growth and overgrowth are already under investigation aiming in treatments that mimic as much as possible the natural process of bone generation in various situations including fracture healing, osteoporosis, and osteoarthritis and other metabolic disorders, in order to more closely resemble the original tissue.

Animals↗
PubMed2006

Gene therapy in orthopaedics.

Impressive advances in our knowledge of the molecular genetic basis of skeletal disorders and fracture healing have led to the development of novel therapeutics based on ectopic expression of one or more genes in patient cells that can influence repair or regenerative processes in bone. Gene therapy is an attractive new approach to the treatment of bone disorders. Orthopaedics has become one of the most promising areas of research into gene therapy. This is because many potential orthopaedic targets for gene therapy, unlike traditional targets such as cancer and severe genetic disorders, neither present difficult delivery problems nor require prolonged periods of gene expression. Gene therapy offers new possibilities for the clinical management of orthopaedic conditions that are difficult to treat by traditional surgical or medical means. Impaired bone healing, need for extensive bone formation, cartilage repair and metabolic bone diseases are all conditions where alterations of the signalling peptides involved may provide cure or improvement. In orthopaedic oncology, gene therapy may achieve induction of tumour necrosis and increased tumour sensitivity to chemotherapy. An increasing amount of evidence indicates that gene transfer can aid the repair of articular cartilage, menisci, intervertebral disks, ligaments and tendons. These developments have the potential to transform many areas of musculoskeletal care, leading to treatments that are less invasive, more effective and less expensive than existing modalities.

Animals↗
PubMed2006

A novel ex vivo culture system for studying bone repair.

Repair of large bony defects still remains a challenge for surgeons. Hydroxyapatite (HA) is well known for its biocompatibility and osseoconduction properties in the osseous environment. In this study the biofunctionality of a newly developed scaffold comprising of collagen and HA, with variable macropores was examined. The biological response was evaluated using primary human osteoblast cells (HOBs). Cell infiltration, proliferation and differentiation were assessed. The results showed that HOBs were able to migrate from the collagen into the HA pores with greater cell migration and infiltration observed in those scaffolds with larger pores. Furthermore, it was shown that Alkaline Phosphatase, a differentiation marker for HOBs was enhanced as the average macropore size increased. This in vitro model provides a more relevant method of testing the biofunctionality and migration ability of cells at a trauma site following implantation in bone and cartilage.

Bone Diseases↗
PubMed2006

Enhancing the osteoinductive properties of hydroxyapatite by the addition of human mesenchymal stem cells, and recombinant human osteogenic protein-1 (BMP-7) in vitro.

Hydroxyapatite (HA) has been widely used as a bone graft substitute. In this study, we investigated whether the addition of osteogenic protein-1 (OP-1) further enhanced the weak osteoinductive properties of hydroxyapatite when loaded with human mesenchymal stem cells (h-MSCs). Over a 14 day period, cell proliferation in both groups was assessed qualitatively using SEM and quantitatively using alamar blue assay. Cell differentiation was also evaluated by measurement of ALP activity, which was expressed against total DNA. HA/MSC loaded with OP-1 demonstrated a statistically significant increase (p<0.001) in cell proliferation at all time points in comparison to unloaded samples. ALP activity per DNA was also significantly enhanced (p<0.001) in loaded samples when compared to unloaded controls. SEM demonstrated increased cellular attachment and proliferation into HA pores at all time points in the loaded samples. Our study suggests that the osteoinductive potential of HA can be improved in vitro by the combined incorporation of MSCs and OP-1.

Adult↗
PubMed2006

In vitro evaluation of the direct effect of estradiol on human osteoblasts (HOB) and human mesenchymal stem cells (h-MSCs).

Estrogen may increase the proliferation of osteoblasts depending upon their differentiation stage. Our objective was to test the hypothesis that estradiol could stimulate the proliferation of primary human osteoblast (HOB) cells or human mesenchymal stem cells (h-MSCs). To test this hypothesis, we investigated two synthetic estradiol preparations: (a) a commercially available one (in clinical use) whose effect was evaluated using MTT assay, trypan blue cell counts and total protein assays; (b) a novel synthetic preparation (not in clinical use) using Alamar Blue assays and scanning electron microscopy (SEM). Commercial estradiol increased HOB proliferation in a concentration-dependant manner between 1 nM and 8 nM reaching significance at a concentration of 8 nM (p<0.001). Small doses of 1 nM and 2 nM increased h-MSC proliferation (p<0.001) but higher doses had no effect. All novel synthetic estradiol preparations decreased HOB proliferation (p<0.001) whereas no direct effect was observed on h-MSCs. Commercial estradiol appears to induce proliferation of HOBs, although its effects on h-MSCs appears to be highly dose-dependent and requires further investigation.

Adult↗
PubMed2005

Current concepts of molecular aspects of bone healing.

Fracture healing is a complex physiological process. It involves the coordinated participation of haematopoietic and immune cells within the bone marrow in conjunction with vascular and skeletal cell precursors, including mesenchymal stem cells (MSCs) that are recruited from the surrounding tissues and the circulation. Multiple factors regulate this cascade of molecular events by affecting different sites in the osteoblast and chondroblast lineage through various processes such as migration, proliferation, chemotaxis, differentiation, inhibition, and extracellular protein synthesis. An understanding of the fracture healing cellular and molecular pathways is not only critical for the future advancement of fracture treatment, but it may also be informative to our further understanding of the mechanisms of skeletal growth and repair as well as the mechanisms of aging.

Animals↗
PubMed2005

Bone substitutes: an update.

Autograft is considered ideal for grafting procedures, providing osteoinductive growth factors, osteogenic cells, and an osteoconductive scaffold. Limitations, however, exist regarding donor site morbidity and graft availability. Allograft on the other hand, posses the risk of disease transmission. Synthetic graft substitutes lack osteoinductive or osteogenic properties. Composite grafts combine scaffolding properties with biological elements to stimulate cell proliferation and differentiation and eventually osteogenesis. We present here an overview of bone grafts and graft substitutes available for clinical applications.

Bone Cements↗
PubMed2005

Dynamic compression plates for Vancouver type B periprosthetic femoral fractures: a 3-year follow-up of 18 cases.

BACKGROUND: There is no consensus on the best surgical treatment of periprosthetic femoral fractures. We report our experience with a dynamic compression plate. PATIENTS AND METHODS: We reviewed the results of 18 periprosthetic femoral fractures treated with open reduction and internal fixation using the dynamic compression plate (DCP). There were 7 Vancouver type B1, 2 type B2 and 9 type B3 fractures. 16 cases had previously undergone at least one revision procedure. In addition to a DCP plate, all B2 and B3 fractures were revised to cemented prostheses, and all B3 fractures were revised with impaction grafting. Mean follow-up was 39 months. RESULTS: The mean healing time for those 11 cases that united was 13 months. One B1-type and one B3-type fracture with plate fracture within 8 months of surgery failed to heal. Furthermore, one B1-type fracture and one B2-type fracture failed and developed nonunion. 3 patients died, from causes not related to surgery, within 8 months after surgery without signs of healing. INTERPRETATION: Open reduction and internal fixation using DCPs seems to be a valid method for the treatment of postoperative periprosthetic femoral fractures with stable stem in place. If the stem is unstable, we suggest that DCPs may be used in association with femoral revision using a long stem. In cases with stable stem (B1), we are inclined to agree with other authors that additional fixation using an extramedullary cortical strut graft may be necessary to improve stability and promote final healing.

Adult↗
PubMed2005

Through-the-nail technique.

Ipsilateral fractures of the neck of the femur and the femoral shaft are uncommon injuries and they present considerable challenge as the concurrent survival of the femoral head and union of the femoral shaft fracture is of paramount importance. We present a young male patient who sustained a Garden IV fracture of the neck of his right femur following a road traffic accident, with the fracture being adjacent to an ipsilateral intramedullary nail inserted 10 years previously for a midshaft femoral fracture; the nail was broken, with its proximal fragment lying behind the greater trochanter. The patient was operated on within 6 hours from the injury. An attempt was made to remove the nail but this was abandoned as warring iatrogenic bone loss was encountered, due to the proximity of the fracture to the nail entry point. Instead, three cancellous lag-screws were inserted to fix the fracture in a triangular fashion. Two screws placed posteriorly behind the nail, and one anterior screw through the nail.

Adult↗
PubMed2004

Revision total elbow arthroplasty with impaction allografting and uncemented partially hydroxyapatite-coated custom-made prostheses.

Total elbow arthroplasty has become a relatively common procedure in the last decade, and the number of primary total elbow replacements performed is likely to continue to increase as the population ages. The incidence of technically demanding prosthesis revisions involving complex problems such as major bone loss is therefore expected to increase. We report 3 cases of total elbow revision arthroplasty, all of which represented patients with severe bone loss. They were all treated using the impaction allografting technique and uncemented custom-made semiconstrained prostheses partially coated with hydroxyapatite manufactured at the bioengineering department of our institution.

Aged↗
PubMed2003

Dall-Miles plates for periprosthetic femoral fractures. A critical review of 16 cases.

Fourteen patients with 16 periprosthetic femoral fractures around hip replacement were treated with Dall-Miles plates between June 1996 and February 2000. There were 10 Vancouver B3, three B1 and three type C fractures. In addition to a Dall-Miles plate, two of the fractures (one B3 and one C type) were also stabilised with one strut graft and nine B3 fractures were revised with impaction grafting. Of the three B1 fractures treated with plates, two failed through fracture of the plate. A further two patients with B3 fractures treated with plates also failed with fracture of the plate. Failure of these plates occurred within 6 months of surgery. All non-unions and fixation failures in this series were in cases where the femoral component did not bypass the most distal fracture line by at least two cortical diameters. The Dall-Miles plates and cable system alone is insufficient for the treatment for periprosthetic femoral fractures. It must be supplemented with additional intramedullary or extramedullary fixation.

Aged↗
PubMed2003

The management of periprosthetic femoral fractures around hip replacements.

Periprosthetic femoral fractures are increasing in frequency and in complexity. They occur intra-operatively, or post-operatively, when they are frequently associated with loosening, with or without osteolysis. Periprosthetic femoral fractures usually occur at low energy levels, either after falls or spontaneously during activities of daily living. At present, the Vancouver classification system probably comes closest to the ideal, as it considers the fracture configuration, the stability of the implant and the quality of the bone stock. When the stem is stable, open reduction and internal fixation is suggested. Several authors have used strut grafts for the treatment of periprosthetic femoral fractures, with good results. If the stem is loose, or revision is indicated for other reasons, it is generally advisable to by-pass the most distal fracture line with a longer stem prosthesis by at least two femoral diameters. Augmentation of this intra-medullary fixation with an external cortical strut to improve rotational stability and/or internally with impaction allografting to compensate for bone defects is also advisable. Vigilant post-operative clinical and radiological assessment following total hip replacement should identify those with recurrent dislocation, loosening, subsidence and osteolysis. These patients are at greatest risk of developing femoral periprosthetic fractures.

Arthroplasty, Replacement, Hip↗