Biomedical subjects
Publications and source records attributed to S Sintzoff.
This work describes the composition, organisation, metabolism, biomechanical and physiologic properties of normal cartilage. The initial involution process, of biochemical nature, preceding by far the morphological changes is described as well as the degenerative, inflammatory and traumatic pathogenesis. The modern cartilage imaging techniques are described with emphasis on MRI.
Magnetic resonance imaging (MRI) of an irreducible knee dislocation can help physicians evaluate associated bone and ligamentous lesions. However, caution should be taken when interpreting the images because the capsuloligamentous interposition seen in irreducible knee dislocations may be misdiagnosed as a meniscal lesion.
The diagnosis of reflex sympathetic dystrophy (RSD) relies on clinical evaluation, scintigraphy or MR imaging, and routine radiographs. Because RSD has variable manifestations with a strong psychogenic overlap, it is desirable to have a noninvasive test to determine the presence of RSD to allow for appropriate treatment. MR imaging allows a differential diagnosis between RSD and other bone lesions. It proves to be a reliable technique in showing and characterizing RSD better than radiographic examination and radionuclide study.
A review of the normal anatomy, developmental abnormalities, traumas and disorders affecting the facet joints is provided, with a recall of the major imaging modalities.
BOP (biocompatible osteoconductive polymer) is a material proposed for osteosyntheses and for filling of bone defects in orthopaedics, neurosurgery and stomatology. It is a composite made of a copolymer of N-vinylpyrrolidone and methylmethacrylate, of polyamide-6 fibers and of calcium gluconate. The histological investigation includes the study of 30 intact rabbit femurs instrumented with a BOP rod, as well as the study of organs of the reticuloendothelial system. The currently available results show the absence of toxicity on hematopoietic tissue. Zones of osteoblastic activity surround the rods, coupled with an osteoclastic reaction which may result in the partial fragmentation of the polyamide fibers and its incorporation in the newly formed bone. We also observed the encapsulation of the material. The biomechanical approach investigated the mechanical properties of the material in bending and in shear. The radiological aspects of the investigation consisted of computerized axial tomography of the implanted femurs to measure density at the bone-implant interface.
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To attest the validity of magnetic resonance imaging (MRI) to evaluate the pathophysiology in nontraumatic osteonecrosis (ON) of the femoral head, we attempted to correlate the different MRI patterns with the histology in cases of early stages. We used not only the T1 and T2 pulse sequences, but also the T1 sequence after gadolinium-DTPA to demonstrate the presence of vascularization. Studying 24 core biopsies from 16 hips (9 patients), we explored the MRI presentations that corresponded to the main histologic findings of the different trabecular bone and bone marrow conditions. Histologic findings including trabecular bone necrosis and bone marrow necrosis represented by amorphous eosinophilic debris presented a low T1 signal intensity without enhancement after intravenous gadolinium injection and a low T2 signal intensity. Trabecular bone necrosis associated with mummified fat cells presented a normal T1 and T2 signal intensity. Trabecular bone necrosis with fibrosis filling the intertrabecular spaces had a low T1 signal intensity that was enhanced by gadolinium and had an intermediate T2 signal intensity. Bands of fibrosis without trabecular bone as seen in fracture zones showed a low T1 signal intensity that was enhanced by gadolinium with a high T2 signal intensity. Thickened trabecular bone with fibrosis as found in creeping substitution areas had also a low T1 signal enhanced by gadolinium, but the T2 signal intensity was low. Farther from the necrotic area, despite normal trabecular bone, we found some patchy necrosis of the bone marrow without any modification of the normal T1 and T2 MRI patterns.(ABSTRACT TRUNCATED AT 250 WORDS)
A 45-year-old woman developed signs of meningeal irritation after myelography with iohexol. Her condition improved very quickly (after antibiotic treatment). Rapid improvement, absence of pathogenic organisms in the pre-treatment CSF culture, the level of CSF pleocytosis and protein were in favor of chemical meningitis.
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