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Biomedical subjects

D Martini

Publications and source records attributed to D Martini.

30 records · Page 2Linked to original sources
PubMed1994

Ultrastructure of heat-deproteinated compact bone.

Heat-deproteinated bone (calcined bone) is a natural candidate for an osteoreproductive biomaterial. Ultrastructural investigation has pointed out an important aspect of the preparation technique. Treatment of bone at temperatures exceeding 500 degrees C causes complete disruption of the tissue architecture and the reorganization of the mineral phase into tightly packed, dense crystals. At 500 degrees C or less the structure and distribution of the mineral phase remain unaffected, so that cross-banded 'shadows' of collagen fibrils are still readily observable, although collagen is no longer present in the samples. By its excellent structural preservation and natural porosity, low-temperature calcined bone seems to be a promising alternative for osteoreproduction.

Animals↗
PubMedDate not supplied

Surgical management of exertional compartment syndrome of the lower leg. Long-term followup.

Forty-six limbs in 28 patients were surgically treated for exertional compartment syndrome. One group of 16 patients (26 limbs) underwent a fasciotomy for exertional anterior compartment syndrome (Group 1). A second group of 12 patients (20 limbs) underwent a fasciotomy for exertional deep posterior compartment syndrome (Group 2). Patients in Group 2 experienced symptoms for a significantly longer time than those in Group 1:16 versus 6.8 months (P < 0.01). All three of the pressure measurements used in this study (resting pressure, 1 minute after exercise, and 5 minutes after exercise) were significantly higher in both groups than in normal controls (P < 0.01). The 1 minute after exercise values were significantly higher in Group 1 (mean, 36.5) than in Group 2 (mean, 29.1) (P < 0.01). In Group 1, 25 of 26 limbs (96%) had excellent results. In Group 2, 13 of 20 limbs (65%) had satisfactory results (5 excellent and 8 good) and 7 (35%) had unsatisfactory results (4 fair and 3 poor). Those patients who had an unsatisfactory outcome did so within 6 months. Patients in Group 1 had a significantly higher rate of satisfactory results than those in Group 2 (P < 0.05).

Adolescent↗
PubMedDate not supplied

Peri-implant medullary cisternae at the interface of bone-smooth surface titanium endosseous implant.

A histological and ultrastructural study was carried out on the spongy bone response to smooth titanium oral implant surfaces. The samples obtained both from monkeys and from patients at various times from the implant insertion revealed that the bone-implant integration developed through different morphological aspects. The implant surface appeared in contact with medullary lacunae, as well as with osteoid tissue or directly with bone matrix. The complementary ultrastructural techniques employed have shown that the medullary lacunae appeared as wide and flattened cisternae delimited by a continuous single layer of flattened cells forming a thin lamina adhering to the implant and an endosteal lamina facing the bone surface. For their position and flattened shape we named them peri-implant medullary cisternae. The presence of blood vessels, reticular cells and myeloid cells in their lumen suggested that these peri-implant medullary cisternae were functional sites of new bone formation.

Animals↗
PubMedDate not supplied

Structure and ultrastructure of the bone/ligament junction.

The tibial insertion of the patellar ligament of rat was investigated at light microscopy, scanning electron microscopy and transmission electron microscopy. Until the point of insertion, the patellar ligament showed the typical structure of a tendon. In proximity to the insertion, the ligament increased in diameter and was gradually infiltrated by a different, cartilage-like matrix. Its tenocytes became progressively rounded and displayed some characteristics of chondrocytes. Tendon fibres crossed this fibrocartilage and arrived well beyond the mineralization front. Finally, they appeared to interweave with the tibial diaphysis bone. These fibres were always distinct from the interposed extracellular matrix and exhibited a different pattern of mineralization from the matrix. Our observations indicate that fibrocartilage does not supersede tendon but merely infiltrates it. Thus, the tendon does not splay during articular movement and the tensile stress is redistributed across the insertion area by increasing the mechanical coupling among adjacent fibres. At the same time, this mechanism provides a structural, uninterrupted connection from tendon to bone which is consistent with the biomechanical requirements it has to withstand.

Animals↗