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Biomedical subjects

M Misasi

Publications and source records attributed to M Misasi.

At least 19 recordsLinked to original sources
PubMed1996

The synovial-like membrane at the bone interface in loose total hip replacements contains high levels of extracellular group II phospholipase A2.

Progressive lysis of bone in loose total hip replacement has been ascribed to the capacity of the synovial-like membrane present at the bone interface to produce prostaglandin E2 and cytokines such as tumor necrosis factor (TNF alpha). Phospholipase A2 (PLA2) produces rate limiting precursor i.e. arachidonic acid in the biosynthesis of various types of biologically active lipids including prostaglandins. It has been shown that extracellular human group II phospholipase A2 is present in large amount in synovial fluid of patients with synovitis and that the expression of this enzyme is under the control of cytokines such as TNF alpha. Furthermore, the human extracellular enzyme has been also shown to induce in an experimental animal model to cause disruption of a synovial like membrane without increasing prostaglandin production. Here we have evaluated PLA2 and TNF alpha levels in the supernatant of homogenate of the synovial-like membrane present at the bone interface retrieved from six patients with a loose non septic failed total hip replacement. In all the membranes examined were found high levels of both TNF alpha (856 +/- 211 units/ml) and extracellular phospholipase A2 (2616 +/- 862 ng/ml). These findings suggest that extracellular PLA2 may play a major role in the process that cause disruption of the membrane at the bone-prosthesis interface.

Bone and Bones↗
PubMed1991

Ultrastructure of periprosthetic Dacron knee ligament tissue. Two cases of ruptured anterior cruciate ligament reconstruction.

Light- and electron-microscopic investigations were performed on two failed Dacron ligaments that had been removed from 2 patients shortly after failure of the implant 2-3 years after reconstruction of the anterior cruciate ligament. Two different cell populations and matrices were correlated with closeness to the Dacron threads. Fibroblasts surrounded by connective tissue with collagen fibrils were located far from the Dacron threads. Roundish cells, appearing to be myofibroblasts surrounded by a more lax connective tissue and elastic fibers, were found close to the Dacron threads. The presence of myofibroblasts and the matrix differentiation could be attributed to the different mechanical forces acting on the Dacron and on the connective tissue because of their different coefficients of elasticity. The sparse occurrence of inflammatory cells in the synovial membrane and in the connective tissue surrounding the Dacron supports the biologic inertness of this artificial material. However, the repair tissue was not structured to resist tension stresses.

Adult↗
PubMed1991

Skeletal changes in thalassemia major.

The authors clinically and radiographically examined 72 patients with homozygous beta thalassemia. The clinical data were compared to the degree of osteoporosis calculated by Singh's method. The results indicate a high incidence of skeletal changes in patients with thalassemia, including lower limb-length discrepancy (16.6%), upper limb-length discrepancy (5.5%), axial deviation of the limbs (8.3%), osteochondrosis (2.7%), and osteopenia (25%). Based on their observations, the authors identify skeletal changes of adulthood (osteopenia) and childhood (limb-length discrepancy, axial deviation, osteochondrosis). The authors hypothesize that osteoporotic changes are caused principally by hyperplasia of the bone marrow, which widens the medullary space and increases intramedullary pressure, leading eventually to osteoporosis.

Adolescent↗
PubMed1991

Ultrastructural aspects of human nonunion.

A histological study on the tissue of nonunion of tibias of two young patients was performed to evaluate the ability of cells to start the mineralization of the matrix. The observations can be summarized as follows: 1) Tissue vessels often appear occluded by thrombotic material; 2) Fibroblasts and chondrocytes found in the nonunion tissue seemed normal, with a good secretion apparatus; 3) The cell membranes were able to produce matrix vesicles; 4) Matrix vesicles and cell membrane looked positive to ALPase reaction, 5) Hydroxyapatite crystals could be observed in the cell matrix or inside matrix vesicles. It may be concluded that cells populating nonunion tissue are well equipped to induct the mineralization of the matrix, but the absence of a blood supply, enough to bring them a normal calcium amount, is the real reason for the nonunion.

Adolescent↗
PubMed1990

[Variations in the rate of erythrocyte sedimentation in the postoperative orthopedic and traumatologic course and their clinical significance].

The authors report their results on E.S.R. variations within the first month post-surgery in 38 traumatologic and orthopaedic patients, to evaluate the time of normalization and its attendibility in case of infection. Normalization was found within the first month postoperatively, without significant differences between orthopaedic and traumatologic patients. They think that the E.S.R. becomes significant on the control of postoperative subacute infection after the third postoperative day and propose E.S.R. evaluation after this period.

Adolescent↗
PubMed1990

[Posterior osteosynthesis in C1-C2 instability].

This is a retrospective study of 8 cases of instability of the C1-C2 segment caused by R.A. or non-union and treated by posterior stabilization with wire loops and bone grafts. The authors reported good results in patients with mild recent neurological involvement and/or radiographic instability of the segment (posterior subluxation of the dens greater than 1/3 of the A-P diameter of C1 or tilting of the dens greater than 30 degrees). The death of a patient with non-union of the dens and severe neurological involvement due to respiratory palsy leads the authors to regard severe long-term neurological involvement (quadriparesis) a contraindication for this type of procedure.

Adult↗
PubMedDate not supplied

Superior thoracic outlet syndrome.

The authors discuss Superior Thoracic Outlet Syndrome (STOS), which is characterized by aspecific symptomatology. However, some tests may be used to reveal the specificity of the disease. In the past, treatment was often followed by recurrence of the disease. In the last ten years, the Roos operation has been used with a high success rate.

Adult↗
PubMedDate not supplied

The diagnosis of lumbar stenosis.

The diagnosis of stenosis of the lumbar spinal canal is essentially based on clinical and radiographic examination. While clinical signs of involvement of the bone structure are few, neurological ones, however aspecific, may be detected (pluriradicular irritation, neurogenic claudication). Neurological instrumental tests (EMG, evoked potentials, etc.) are not of considerable aid to diagnosis. Radiographic examination, CT and MRI, are essential to prognosis and therapy.

Diagnosis, Differential↗
PubMedDate not supplied

Osteoporosis in patients affected with thalassemia. Our experience.

The authors examine 72 patients affected with homozygous B-thalassemia; The study was conducted by clinical-hematological and radiologic examination. The Singh method is used to compare clinical data with the degree of osteoporosis. The results indicate that there is a high frequency of osteoporotic abnormalities in thalassemia. The authors postulate that osteoporotic lesions are principally caused by hyperplasia of the marrow, the overactive bone marrow widening the medullary space and the increased intramedullary pressure causing osteoporosis.

Adolescent↗