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Biomedical subjects

A Sudanese

Publications and source records attributed to A Sudanese.

At least 19 recordsLinked to original sources
PubMed2000

Cytokines and osteolysis around total hip prostheses.

The aim of this work is to assess the correlation between the osteolysis around the prosthesis and the presence of cytokines favouring inflammation in the tissues at the interface between loosened prosthesis and bone. In this study, twenty-nine patients that underwent revision surgery were examined. Bioptic samples were collected at the interface between bone and implant both at the stem and socket level. Semiquantitative immunohistochemistry was performed to detect interleukin 1 alpha, interleukin 1 beta, interleukin 6 and tumour necrosis factor, cytokines that directly cause bone resorption and indirectly induce synthesis of other bone resorbing cytokines. Wear particles were identified and quantified by light microscopy. Radiographic evidence for osteolysis was scored by the Engh and Bobyn score. In tissues collected at the interface, the percentage of cells positive to IL1, IL6 and particularly to TNF increased in relation to the tissues collected at the interface with stable components. The cells occurring in the new capsule do not secrete cytokines in quantities that can be related to severity of wear. Cemented prostheses showed higher incidence of severe osteolysis, and higher levels of cytokines. It can be concluded that TNF, and to a lesser extent IL1 and IL6, are positively related to the severity of osteolysis around the prosthesis and therefore a pharmacological treatment can be hypothesized with anti-inflammatory or anti-cytokine drugs in order to limit or to avoid prosthesis loosening.

Adult↗
PubMed2000

Evaluation of radiolucency condition in total hip arthroplasty: a statistical comparison of the diagnostic capability of digitised image vs. conventional X-ray film.

This work analyses the diagnostic capability of radiographic images taken from patients with total hip arthroplasty and visualised on monitor. Images were obtained with digital acquisition of conventional X-ray films. The investigated pathology is the absence of direct contact between bone and prosthesis (radiolucency). Three senior orthopaedists defined the diagnostic "truth" on well-defined regions of interest on 22 conventional X-ray films of total hip arthroplasty, obtaining a total of 110 reference ratings. Films were digitised by use of an X-ray scanner. Four readers evaluated the X-ray images, applying conventional and monitor visualisation. To show any difference between ratings on film and ratings on monitor a sensitivity, specificity and accuracy study jointly with a receiver operating characteristics (ROC) study were performed for each reader and for all combined readings. The intra-observer reproducibility of the radiographic protocol was equal to 87% and the inter-observer one was in the range 85-92%. The sensitivity, specificity and accuracy study together with the ROC analysis did not show significant differences between the two evaluation modes. The evaluation of radiolucency from digitised X-ray films visualised on a monitor resulted statistically comparable with the conventional evaluation on X-ray films.

Diagnosis, Computer-Assisted↗
PubMed2000

Apoptosis in peri-implant tissue.

The authors examined 54 biopsies taken from the tissue surrounding loosened hip joint prostheses. In situ apoptotic cell identification was performed by the detection of single- and double-stranded DNA breaks that occurred in the early stages of apoptosis. Both types of breaks can be revealed by labeling the free 3'-OH termini with modified nucleotides (fluoresceine-dUTP) in an enzymatic reaction catalyzed by terminal deoxynucleotidyl transferase (TdT). Results were correlated with the presence of wear debris in the tissue and with the use of bone cement for prosthesis fixation. Apoptotic cells were present in a higher percentage in tissue sections where metal particles were present (24% apoptotic cells) if compared to areas where no wear (6%), or plastic wear (2.8%) or ceramic wear (1.5%) was observed. Apoptosis is neither related to bone cement, nor to the time it takes for the implant to fail. Cell death by apoptosis may be important in implants which release metal ions by corrosion or wear and may have been underestimated up to now, as it is a 'clean' way of cell death, leading to limited damage in the surrounding tissues.

Acetabulum↗
PubMed2000

Expression of the CD69 activation antigen on lymphocytes of patients with hip prosthesis.

The aim of the study was to evaluate the sensitization to metals in patients with Co-Cr hip prosthesis. Peripheral blood mononuclear cells (PBMC) were collected from 14 healthy donors and three groups of patients: 10 candidates for primary total joint replacements, 11 patients with well-fixed implant and 13 patients with aseptic loosening of the hip prosthesis. PBMCs were cultured with the metal ions employed for implant manufacturing and the expression of CD69 activation antigen on CD3/T lymphocytes was detected by flow cytometry. Chromium extract increased significantly the expression of CD3/CD69 phenotype in patients with loosening of hip prosthesis. The chromium-induced 'activation index' was higher in patients with loosening of hip prosthesis than in healthy donors and in pre-implant patients. The cobalt-stimulated PBMC of patients with either well-fixed or loosened prosthesis had an 'activation index' significantly higher than healthy donors. The activation index values were used to graduate the PBMC-response as 'normal' (> or = 0.9 and < 2), 'low' (< 0.9) and 'high' (> or = 2): an high-activation index was observed only in chromium-exposed PBMC of patients with prosthesis. Our data show that chromium released from orthopedic implants could be responsible for the lymphocyte sensitization and flow cytometry is an easy and reliable method for monitoring the hypersensitivity state in patients with metal prostheses. Activated lymphocytes in the peri-implant tissue are likely to elicit a localized immune response and contribute to maintain the inflammatory process evolving in the implant failure.

Aged↗
PubMed1999

Cytokine release in mononuclear cells of patients with Co-Cr hip prosthesis.

The aim of this study was the evaluation of the release of bone-resorbing cytokines in peripheral blood mononuclear cells (PBMC) of patients with aseptic loosening of Co-Cr hip prostheses. TNF-alpha, IL-6, and GM-CSF were measured in both unstimulated and PHA-stimulated PBMC, and in PBMC cultured in the presence of chromium and cobalt extracts. Blood samples from healthy donors were used as controls. Serum samples of both patients and healthy donors were tested to determine the concentration of metal ions. The proportion of lymphocyte, monocyte and lympocyte subpopulation in cultured PBMC did not differ in patients and the control group. In unstimulated PBMC the release of TNF was significantly higher in patients than in the control group, while IL-6 was significantly decreased and no change was observed for GM-CSF. When the PBMC were challenged with chromium extract, all the 'index of cytokine release' resulted higher in patients than in the control group; cobalt extract increased both the TNF and GM-CSF index, but not the index of IL-6 release. Metal concentrations in serum from patients were significantly increased and correlated with the TNF release in PBMC stimulated with both metal extract. Our results suggest that a CoCr-implant releases a large amount of metal ions which could mediate the priming or the renewal of a cell-mediated hypersensitivity reaction. The prevalence of circulating lymphocytes responsible for the delayed hypersensitivity, namely Thl, would justify both the significant increase of TNF and the significant decrease of IL6 in unstimulated PBMC of patients, as well as the significant increase of the 'index of cytokine release' after the challenge with metal ions.

Adult↗
PubMed1999

Wear debris and cytokine production in the interface membrane of loosened prostheses.

In this study, thirty-nine patients were examined. All of them suffered from hip joint prostheses loosening and underwent revision surgery. Bioptic samples were collected at the interface between bone and implant either at the stem or cotyle level. Immunohistochemistry was performed to detect IL-1alpha, IL-1beta, IL-6 and TNF, cytokines that directly cause bone resorption and indirectly induce synthesis of other bone resorbing cytokines. Quantitative analysis of the positive cells and correlation with clinical data was performed. It resulted that there is a great variability in positive cells for cytokines according to the harvest site; anyway, cytokines tend to be higher in patients carrying a joint prosthesis with polyethylene acetabular component and it is associated with plastic wear particles, even though there is no direct correlation between wear amount and cytokine levels. There is a statistically significant negative correlation between metal wear and a cytokine (IL-6); cytokines levels do not depend on the implant time to failure and do not correlate with pain score. As expected, cytokines levels tend to be lower in subjects being treated with non-steroidal antiinflammatory drugs. It can be concluded that plastic wear is the factor inducing the highest cytokine levels in the tissues around the prosthesis at the interface; cytokines that are an indicator of osteolysis risk.

Adult↗
PubMed1998

Bone-resorbing cytokines in serum of patients with aseptic loosening of hip prostheses.

Our aim was to determine if the serum levels of bone-resorbing cytokines (IL-1beta, TNF-alpha, IL-6, GM-CSF) are altered in patients with aseptic loosening of a total hip prosthesis, and if such levels are influenced by the type of implant. We determined cytokine levels in sera from 35 patients before revision for failed total hip arthroplasty and compared them with those in 25 healthy donors. We also assessed the soluble receptor of interleukin-2 (sIL-2r) in serum as an indication of a specific immune reaction against the implant. Our findings showed that the sIL-2r and TNF-alpha serum level did not change. The IL-6 level was not significantly altered, but was higher in patients with TiAIV prostheses than in those with a CrCoMo implant and in patients with cemented prostheses. The IL-1beta level was found to be higher in those with a TiAIV cemented prosthesis than in the control group (p=0.0001) and other groups of patients (p=0.003 v uncemented TiAIV, p=0.01 v cemented CrCoMo, p=0.001 v uncemented CrCoMo). The GM-CSF level significantly increased in patients compared with healthy subjects (p=0.008), and it was higher in those with cemented than with uncemented implants (p=0.01). Only patients with cementless CrCoMo prostheses had levels of GM-CSF similar to those of the control group. The highest GM-CSF concentrations were observed in patients treated with non-steroidal anti-inflammatory drugs (NSAIDs) in the last months before revision (p=0.04). In addition, when massive osteolysis was observed, the level of GM-CSF tended to decrease to that of the control group.

Acetabulum↗
PubMed1994

Cytotoxicity testing of cyanoacrylates using direct contact assay on cell cultures.

The use of a tissue adhesive for surgical procedures has prompted a large number of clinical and experimental studies. Alkyl-2-cyanoacrylate esters constitute a family of adhesives with good mechanical properties but their biological compatibility has to be assessed. In this study the cytotoxicity of three commercially available cyanoacrylates and one of unknown composition has been determined. The first part of the study deals with direct contact testing procedures using L 929 cells challenged with drops of adhesives: cell morphology, cell growth and bacterial growth inhibition were assayed. Testing methods included cell viability assay using vital dyes, cell growth measurement using crystal violet staining uptake and bacterial growth assay using S. aureus growth inhibition. All the cyanoacrylate adhesives tested were found to be cytotoxic and to inhibit cell proliferation: differences between the cyanoacrylates were found.

Adhesives↗
PubMed1994

Toxicity of cyanoacrylates in vitro using extract dilution assay on cell cultures.

Comparative cytotoxicity testing of four cyanoacrylate adhesives suggested for orthopaedic applications was performed. These substances were placed in complete culture medium with serum and the resulting extraction fluids were tested on L 929 cells and human lymphocytes. Testing procedures include cell morphology assessment using light microscopy and vital dyes, cell counting using a computer-assisted image analysis system, cell growth measurement using total protein content assay and cell viability assessment using the MTT method. Quantitation of the toxicity of the degradation products released by cyanoacrylates in the extracts was achieved and differences in the cytopathic effect related to the chemical composition of the cyanoacrylates were found. A toxicity rating of the assayed cyanoacrylate adhesives was obtained as follows (in order of increasing toxicity): BCA < xCA < ECAg < ECAl.

Adhesives↗
PubMed1994

Bone demineralization induced by cementless alumina-coated femoral stems.

The biologic compatibility of ceramic materials has been widely demonstrated, and alumina (Al2O3) has been used extensively in clinical applications for nearly 20 years. The authors examined the behavior of bone tissue adjacent to the alumina coating in eight cementless hip prosthetic stems that appeared radiologically stable and were explanted because of pain. Histologic evaluation demonstrated the presence of a consistent layer of decalcified bone tissue in continuity with and parallel to the prosthetic interface. Based on laboratory findings, the authors attribute this demineralization phenomenon to a high local concentration of aluminum ions with metabolic bone disease, which is histologically comparable to the osteomalacic osteodystrophy described in dialysis patients. These findings must be carefully considered given the potential long-term implications for alumina-coated implants.

Aged↗
PubMed1994

Incidence of intraoperative femoral fracture. Straight-stemmed versus anatomic cementless total hip arthroplasty.

The authors report the incidence of intraoperative femoral fractures (16 cases) occurring during the course of 395 cementless total hip arthroplasties performed at the Rizzoli Orthopaedic Institute between November, 1980 and June, 1991. The straight stem (Lord prosthesis) caused an intraoperative fracture in 18% of the cases, whereas the anatomic stem (An.C.A.) caused a fracture in only 1.5% of the cases. An intraoperative fracture occurred in 13% of patients with osteoporosis and only in 1.4% of those with normal mineralization of the proximal femur. Seven cases required circlage wiring; one was treated with interfragmentary screws (in the diaphysis). The remaining patients were treated with casting or delayed weight-bearing. Fifteen fractures consolidated within an average of 10 weeks. One case treated with circlage wiring and screws resulted in a nonunion. After 7 months, internal fixation with a plate and screws was performed with consolidation 5 months later. All stems were radiographically stable at an average follow-up of 40 months.

Female↗
PubMed1993

Digital dynamic range expansion applied to X-ray densitometric analysis of total hip replacement.

Due to the presence of the stiff prosthetic stem fitted in the medullary canal during total hip replacement, the surrounding cortex of the femur changes its density over time. This bone remodelling takes place with every type of total hip prosthesis; however, its intensity may vary between prostheses and patients. In the worst cases this process can lead to the late failure of the implant. To monitor such bone density evolution, we are developing a tailored Computer-aided Densitometric Image Analysis system (the major part of this our system uses an 8-bit commercial hardware with 256 levels of grey). The equivalent dynamic range of an X-ray picture is about 10 bits. In this paper we present a method to overcome these hardware limitations by improving the software. Using a double-exposure acquisition it is possible to build a 9-bit image that is good enough for most applications involving bone density measurement.

Absorptiometry, Photon↗
PubMed1993

Morphometric and microanalytical analyses of alumina wear particles in hip prostheses.

We analysed tissues harvested during 24 retrievals of hip joint prostheses, with one or both articular components made of alumina. We describe the morphology of wear particles, measure their size and analyse their chemical composition. We relate histopathological aspects to the parameters that characterize ceramic wear particles, and notice that tissue reaction relates to the physical aspect and amount of wear debris and does not necessarily depend on their chemical composition.

Aluminum Oxide↗
PubMed1993

A software simulation of tibial fracture reduction with external fixator.

In modern orthopaedic practice, circular external fixators are frequently preferred to plaster cast for various reasons. The realignment of the two fractured bone segments is usually performed under a continuous fluoroscopy checking which involves a long radiation exposure time for both patients and surgeon. In order to overcome this problem, a computer controlled external fixator is under development. One relevant problem which this project faced in its initial stage was the difficulty to define in geometrical terms the manual reduction trajectory normally adopted by the surgeon. Basically it was a typical problem of empirical knowledge transfer from the surgeon to the engineer. Thus, it was necessary to create a common ground where the two experts could carry out the necessary analyses in order to define an empirical algorithm capable of suggesting a correction trajectory. The problem was solved by developing a simulation program called S.E.R.F. (Simulation Environment of a Robotic Fixator) provided with an extremely powerful graphic output, able to visualize the whole reduction trajectory from any viewpoint in space. The authors suggest the use of this kind of tool every time the techno-clinical information exchange is a critical issue.

Algorithms↗
PubMed1993

The role of surgical therapy in patients with nonmetastatic Ewing's sarcoma of the limbs.

Of 131 patients with primary Ewing's sarcoma (ES) with extremity locations, treated between April 1972 and May 1987, 13 had amputation; 56 had a local resection with 31 (55%) requiring radiation therapy (RT) as an adjuvant to local therapy. Sixty-two of 131 patients (47%) had RT only. Local recurrences were reported in 5% of patients treated with surgery alone, 1% of the group treated with surgery and radiation therapy, 24% of patients treated with radiation therapy alone (46% for cesium-radiation therapy, and 12% with cobalt-radiation therapy).

Adolescent↗
PubMed1992

Microradiographic and histochemical evaluation of mineralization inhibition at the bone-alumina interface.

Microradiographic and histochemical tests were used to examine the behaviour of the bone tissue close to the alumina coating in cementless hip prostheses which were radiologically stable and explanted because of pain. The presence was detected of a decalcification stripe of the bone tissue with a thickness of about 300 microns, parallel to the prosthesis profile and in appearance not influenced by the roughness of the surface. This phenomenon was attributed to the presence of aluminium ions similarly to what happens in osteomalacic osteodystrophy in nephropathic dialysed patients. It was concluded that the phenomenon must be carefully considered because, in the long term, it could cause failure in the alumina coating.

Aluminum↗
PubMed1990

Ewing's sarcoma of the pelvis.

Two hundred and thirty-nine patients with Ewing's sarcoma were treated at our institution between 1972 and 1987: 42 of these had lesions in the pelvis, 29 were in the wing of the ilium or involved the sacroiliac joint (type I), 5 were periacetabular (type II), and 8 were in the anterior pelvic arch (type III). Radiotherapy alone was used for the primary lesion in 11 cases, adjuvant chemotherapy in 20 and a neoadjuvant protocol in 22. The overall disease-free survival at a mean follow up of 34 months was 19%. There was no difference in survival related to age or the site in the pelvis, none in disease-free survival with adjuvant and neoadjuvant chemotherapy, or in the incidence of local recurrence and metastases in these two groups. Similarly, there was no difference in disease-free survival between operative treatment, with or without radiotherapy, and radiotherapy alone. There was a slight trend towards better local control of the disease in the former group compared to the latter, although this difference was not statistically significant. Our conclusion is that treatment needs to be planned for each individual patient.

Adolescent↗