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Biomedical subjects

G Maccauro

Publications and source records attributed to G Maccauro.

17 recordsLinked to original sources
PubMed2007

Methotrexate-added acrylic cement: biological and physical properties.

BACKGROUND: Previous reports have demonstrated the suitability of adding different chemotherapeutic drugs to acrylic cement for the treatment of bone metastases. The best results so far have been obtained with methotrexate (MTX) for which diffusion from the implanted cement has been demonstrated both in vitro and in vivo. In this study the suitability of adding MTX to acrylic cement as local adjuvant chemotherapy was investigated. METHODS: Using an in vitro model of human breast cancer cells we demonstrated that the drug is eluted in an active form able to exert a cytotoxic effect over a long period of time. The use of different concentrations of drug on the kinetic of elution and on the mechanical properties of cement was also evaluated. RESULTS: The results obtained suggest that the release of MTX is higher at the beginning and progressively decreases over time being affected by the concentration of drug used. Our results also demonstrated that the addition and the subsequent elution of MTX does not alter the compressive properties of the cement. CONCLUSION: These findings confirm the suitability of MTX-supplemented cement and support its use as an effective aid for the management of bone metastases requiring surgical curettage and acrylic cement implantation for structural support.

Antineoplastic Agents↗
PubMed2006

A particular solution in the treatment of primitive neoplasms of the distal third of the tibia. Presentation of a clinical case and review of the literature.

Primitive malignant neoplasms affecting the distal third of the tibia are altogether rare, and their treatment is considerably controversial. The authors describe the diagnostic procedure and a particular surgical strategy of limb salvage in a case of malignant fibrous histiocytoma located at the distal third of the tibia, in particular pointing out the difficulties in restoring the continuity of the skeletal tissues and of the muscle, and with a review of the relevant literature.

Bone Neoplasms↗
PubMed2006

On the fracture of a zirconia ball head.

Y-TZP ball heads were introduced into the market in 1985. Since then these components have had wide diffusion in hip replacements, due to their good mechanical performance and reliability. Namely, only a few papers were published up to year 2000 reporting failures of Y-TZP ball heads. The worldwide recall in August 2001 of some Y-TZP batches changed this situation. This paper analyse the material of a ceramic ball head that fractured in vivo 34 months after surgery. The retrieved fragments were submitted for visual inspection, fractographic analysis by optical microscopy, X-ray diffractometry, and FEG-SEM ceramography analysis. The results obtained show that the hydrothermal stability of the material had only a secondary role in the fracture. The literature reporting on failures of THR making use of Y-TZP ball heads is discussed.

Biocompatible Materials↗
PubMed2004

Fracture of a Y-TZP ceramic femoral head. Analysis of a fault.

We studied factors contributing to the initiation of fracture and failure of a zirconia ceramic femoral head. The materials retrieved during a revision total hip replacement were submitted to either visual, stereomicroscopic and scanning electron microscopy (SEM) or SEM and energy-dispersive X-ray analysis. X-ray diffraction was performed in order to investigate the extent of tetragonal to monoclinic phase transition. Histological examination was performed on the periprosthetic tissues. The results showed that failure was due to the propagation during clinical use of defects which may have been introduced into the material during the processing of the ceramic, rather than those intrinsic to zirconia. The literature relating to previous failures of zirconia components is reviewed.

Ceramics↗
PubMed2003

A very rare localization of metastatic lung carcinoma to the interosseous membrane.

INTRODUCTION: Soft tissue is a rare localization of carcinoma metastasis. Skeletal muscle is considered the most frequent site. The aim of this paper is to report a very rare localization of soft-tissue metastasis of lung adenocarcinoma in the lower leg interosseous membrane, surgically treated at our department. MATERIALS AND METHODS: A 66-year-old man with a history of lung adenocarcinoma was admitted to our department because he complained of a pain resistant to drugs that had persisted for 1 month. Imaging showed that the lesion was unique, localized in the interosseous membrane, with a distal margin more than 2 cm above the ankle platform. A distal fibula resection, including the tumour and a reconstruction according to Capanna type A2 was performed. RESULTS: At the 6 months follow-up, the patient was walking without external support. CONCLUSION: Surgery is not the treatment of choice for soft-tissue metastases, but it may be recommended when the lesion is unique and inducing a pain resistant to anti-inflammatory drugs.

Adenocarcinoma↗
PubMed2003

Acrylic cement added with antiblastics in the treatment of bone metastases. Ultrastructural and in vitro analysis.

An increased long-term survival of patients with alignant tumours also increases the possibility of the development of skeletal metastases and pathological fractures. The management of bone metastases includes the removal of gross disease and the administration of local adjuvants. We have investigated the possibility of adding antiblastic drugs to acrylic cement. Cylinders of acrylic cement were manufactured containing three different antiblastic drugs, methotrexate, cisplatin and doxorubicin. We performed in vitro analysis on MCF-7 human breast cancer cells in order to evaluate the biological effect of the mixtures and surface analysis of the acrylic cement-cisplatin cylinders using energy-dispersive x-ray analysis (EDAX). All drugs were released in an active form from the cement. Each drug had a different effect on cell viability. Doxorubicin had the greatest effect on breast cancer cells. Surface analysis showed that antiblastic drugs were present in the form of granules. These results confirm the potential of antiblastic-loaded cement as a possible adjuvant in the local treatment of bone metastases. Further studies should be undertaken to determine whether the release of antiblastic drugs from cement is elution or if they are only released from the surface.

Antineoplastic Agents↗
PubMed2000

Surface analysis of a femoral stem after failed total hip replacement.

We analysed the surface of a Ti alloy femoral stem in a cementless total hip replacement with early failure. A specific protocol consisting of non destructive and destructive tests was used in the evaluation of the retrieved stem. The tests confirmed that implant fretting due to bone abrasion constitutes an early phase of loosening.

Aged↗
PubMed1999

Bilateral acetabular fracture without trauma.

In the absence of trauma fracture of the acetabulum is an extremely rare injury. We describe a 70 year old man who spontaneously developed fractures in both acetabulae due to bony insufficiency. It was successfully treated by bilateral total hip replacement.

Acetabulum↗
PubMed1999

Zirconia as a ceramic biomaterial.

Zirconia ceramics have several advantages over other ceramic materials, due to the transformation toughening mechanisms operating in their microstructure that can give to components made out of them, very interesting mechanical properties. The research on the use of zirconia ceramics as biomaterials started about twenty years ago, and now zirconia (Y-YZP) is in clinical use in THR, but developments are in progress for application in other medical devices. Recent developments have concentrated on the chemistry of precursors, in forming and sintering processes, and on surface finish of components. Today's main applications of zirconia ceramics is in THR ball heads. This review takes into account the main results achieved up to now, and is focused on the role that microstructural characteristics play on the TZP ceramics behaviour in ball heads, namely mechanical properties and their stability, wear of the UHMWPE paired to TZP, and their influence on biocompatibility.

Animals↗
PubMed1999

In vitro evaluation of the mutagenic and carcinogenic power of high purity zirconia ceramic.

Tetragonal zirconia polycrystal (TZP) is a new interesting ceramic for the manufacture of medical devices. Its wide use in orthopedic and odontoiatric implants was limited till now by the high chemical and radiochemical impurities of the raw materials. Purification processes now available allow to obtain high purity ceramic grade powders suitable for TZP ceramics manufacture, even if their possible mutagenic and transforming effects are still unclear. The aim of this work is to study in vitro the mutagenic and oncogenic effects of a new zirconia ceramic stabilized by yttria (Y-TZP). This ceramic was sintered from high purity powders obtained by a process developed under a project carried out within the Brite EuRam programme. For comparison, ceramics made from unpurified zirconia powder were also tested. Fibroblasts irradiated by a linear accelerator were used as positive control. The results obtained show that Y-TZP ceramic does not elicit either mutagenic or transforming effect on C3H/10T(1/2) (10T(1/2)) cells and demonstrate that ceramic from high purity powders can be considered suitable for biomedical applications from the point of view of the effects of its radioactive impurity content.

Animals↗
PubMed1999

Analysis of a failed alumina THR ball head.

The favourable properties, on which is based the successful history of the use of alumina in orthopaedic surgery, are due to the tough control made by manufacturers on the whole process from raw materials purity to the quality controls. The minimum requirements of a medical grade alumina are stated from 1981 in ISO 6474 standard. Nevertheless, due to the voluntary character of standards, and lack of national and international laws, it was possible in the past to introduce into the market materials with characteristics not in compliance with the standard ISO 6474. A THR implanted on a fifty years old patient was revised three years after implantation, due to the failure of the alumina ball head. To understand the causes of such an early failure, the fragments of the retrieved ball head were submitted to a series of non destructive and destructive controls. The results show that the poor quality of the design and manufacture of the implant was the origin of the failure.

Aluminum Oxide↗
PubMed1998

Y-TZP ceramics for artificial joint replacements.

Due to their excellent mechanical properties, Yttria-stabilized Tetragonal Zirconia Polycrystal ceramics (Y-TZP) are used in ball heads for Total Hip Replacements. It is known that Y-TZP materials may show strength degradation due to ageing or to hydrothermal treatment. Also high wear of UHMWPE sockets coupled to steam sterilized Y-TZP ball heads after a short implantation period was recently reported. This effect may be related to ball head surface phase transformation, due to corrosive attack. The aim of this study is the evaluation of Y-TZP ceramics stability. Y-TZP made out of Yttria coated powders were aged at 140 degrees C under 0.2 MPa water pressure, in Ringer's solution at 37 degrees C, in NZW rabbits. Samples made out Yttria coated powders show lower strength degradation than samples made out coprecipitated powders, and UHMWPE discs coupled to Y-TZP rings made out coated powders do not show increase in wear after repeated sterilization cycles of the ceramic rings.

Animals↗
PubMed1997

Massive osteolysis induced by high molecular weight polyethylene wear debris.

We investigated the mechanism by which particulate wear debris of polyethylene may induce bone resorption using an in vivo model. Two uncemented total hip prostheses, in which the socket was directly in contact with acetabular bone, were selected because there was massive bone loss around the implant. A thick synovium-like layer was found at the polyethylene-bone interface during revision operations. Samples were examined by transmitted and polarised light microscopy, and by transmission electron microscopy. This study demonstrates that polyethylene wear products alone can cause massive osteolysis by triggering the formation of foreign body granuloma at the bone-implant interface.

Female↗
PubMed1994

Fracture callus in osteopetrosis.

The histologic features of bone callus after a traumatic fracture in a patient with osteopetrosis are presented. The fracture callus develops in stages that are apparently normal. The tissue is initially rich in bone-forming cells and vessels. One year later, however, unlike mature osteopetrotic bone, the tissue shows no Haversian organization.

Adult↗
PubMedDate not supplied

Bone metastasis in hepatocellular carcinoma. A report of five cases and a review of the literature.

Hepatocarcinoma occurs frequently throughout the world. Bone metastases are rare although incidence has increased because of progress in diagnosis and treatment. The authors report 5 cases of bone metastases and review the literature. The spine is the most frequent localization of bone metastases. Radiotherapy is the treatment of choice for this lesion. Surgery should be used to prevent and treat complications such as nerve compression and pathologic fracture, only if the coagulative pattern and the conditions of the patient allow it. The authors recommend the use of long intramedullary nailing when localization of the disease is in the femur, with prophylactic stabilization of the neck in diaphyseal metastasis.

Carcinoma, Hepatocellular↗