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Biomedical subjects

L Sedel

Publications and source records attributed to L Sedel.

At least 37 records · Page 2Linked to original sources
PubMed2002

[Intracardial migration of a bullet: diagnosis and management].

Venous pellet embolism to the cardia after shotgun wound is a very rare occurrence. Number and size of pellets, at the impact make this migration easier; embolism is asymptomatic and may occur 15 years after the injury. Many problems must be mentioned: mechanics of entry into the heart (own velocity, venous flow), topographic diagnosis (chest X-ray, transthoracic, transoesophageal ultrasound and CT-scan), local outcomes of this projectile (local erosion, clot, endocarditis), destination of a new migration (pulmonary embolism, left heart), indications of extraction, supervision. Extraction musn't be systematic, but only in the event of a patent foramen ovale with a risk of systemic embolism, which clinical outcomes are most serious or in the event of complications. The authors report on a 22 years old patient observation whose treatment was abstention and supervision.

Adult↗
PubMed2001

In vivo tracking of bone marrow fibroblasts with fluorescent carbocyanine dye.

Recent advances in the field of tissue engineering have culminated in new tissue substitutes that combine a biomaterial and precursor cells. The effectiveness of these materials is generally assessed in animals, but few studies explore the fate of the transplanted cells in vivo, despite its paramount importance for understanding the function of the engineered tissues. Current methods that use reporter genes or chimeric animals are not always well suited to solving tissue-engineering problems. We therefore developed a new method for irreversible labeling of cells to track their fate in vivo. We used a fluorescent lipophilic probe, CM-Dil, that avidly binds to the cell membrane. Human bone marrow stromal fibroblasts could be labeled with 20 microM CM-Dil in 30 min. The CM-Dil was not cytotoxic and did not affect cell proliferation in vitro. Cells could be monitored for up to 30 days when placed in a coral scaffold and implanted intramuscularly or in a bony site. However, the fluorescence intensity decreased roughly in parallel with the number of cell divisions. This fact needs to be taken into account during the design and interpretation of experiments. We believe that this technique is also of interest for other cell types.

Bone Marrow Cells↗
PubMed2001

[Bone substitutes].

Explore the source record for details and available documents.

Biocompatible Materials↗
PubMed2001

Long-term in vivo bioactivity and degradability of bulk sol-gel bioactive glasses.

Melt-derived bioactive glasses have been used with success in various clinical applications for over 10 years. Recently, particles of sol-gel-derived bioactive glasses with an initial high specific surface area have been shown to exhibit excellent osteoconductive properties as well as significant degradability. In this work, we explored the long-term in vivo bioactivity and degradability of bulk sol-gel-derived glasses in a rabbit model. Two sol-gel compositions (58S and 77S Bioglass) were used. Bulk 45S5 Bioglass was used as a control. Both sol-gel-derived glasses demonstrated osteoconductive properties similar to 45S5 Bioglass. In addition, absorbability was observed for both sol-gel-derived glasses starting after 12 weeks of implantation. Total absorption reached 40% after 52 weeks. No degradation could be measured in the case of bulk 45S5 melt-derived Bioglass within 1 year of implantation. The degradation process was highly time dependent, as demonstrated by regression analysis. New bone formation was found to fill in areas that had been resorbed, similar to bone remodeling. This absorbability can be assumed to be at least partially related to an osteoclastic resorption as viable osteoclasts-like cells were found to be in direct contact with the glass surfaces.

Absorbable Implants↗
PubMed2001

Prevention of wear and osteolysis: alumina-on-alumina bearing.

Alumina-on-alumina bearings in total hip replacement have been used for 30 years. Excellent tribologic properties and extra low debris generation could, in theory, provide an answer to osteolysis. A review of the authors' experience with alumina-on-alumina bearings showed that, except in a few bearings that had been loose for a long time, osteolysis was not a problem. Although the cemented titanium stem and the alumina-on-alumina couple were not a problem, fixation of the socket had to be improved. To improve the socket fixation system and to avoid the use of a cemented titanium stem that may have created problems in the long-term, a new design was introduced in 1997. The current authors present the preliminary results of the first 96 hips with cementless fully-coated hydroxyapatite titanium alloy stems and sockets, 32-mm alumina femoral head, and alumina liner, both held with a Morse taper. Ninety-six consecutive hips in 89 patients (57 males, 32 females) with a median age of 46 years (range, 14-72 years) were analyzed. One socket was revised at 4 months because of poor primary stability in a patient with a severe acetabular fracture. One patient experienced a traumatic fracture of the implanted femur 3 weeks after surgery. The mean followup was 16 months (range, 4-38 months). One patient died from rupture of an aneurysm. Ninety-three hips in 86 patients were assessed regarding the clinical and radiologic ratings. Two patients (two hips) were interviewed by telephone. The Merle d'Aubigné rating system was 18 in 65 hips (59 patients), 17 in 25 hips (25 patients), and 16 in three hips (three patients) mainly related to a previous disability including limp, sciatic palsy, or stiffness. Examination of 93 available radiographs revealed no ostelolysis, no radiolucent lines at the last examination, and no subsidence. The level of excellent results, even in this young population, and lack of osteolysis and wear are encouraging, even if the followup is too short to allow any conclusions to be made.

Adolescent↗
PubMed2001

Hydroxyapatite-coated versus grit-blasted femoral stems. a prospective, randomised study using EBRA-FCA.

We have carried out a prospective, randomised study designed to compare the long-term stability of the stem of cementless femoral implants with differing surface configurations. A total of 50 hips (46 patients) was randomised into two groups, according to whether the medullary stem had been grit blasted (GB) or coated with hydroxyapatite (HA). Both femoral prostheses were of the same geometrical design. We used Ein Bild Roentgen Analyse femoral component analysis (EBRA-FCA) to assess the stability of the stem. The mean follow-up was for 8.66 years. The mean migration of the stem was 1.26 mm in the HA group compared with 2.57 mm in the GB group (Mann-Whitney U test, p = 0.04). A mixed model ANOVA showed that the development of subsidence was statistically different in the two groups during the first 24 months. After this subsidence increased in both groups with no difference between them. Our results indicate that, with the same design of stem, HA coating enhanced the stability of the femoral stem when compared with GB stems.

Adult↗
PubMed2001

Comparative analysis of two different types of alumina-alumina hip prosthesis retrieved for aseptic loosening.

We compared and quantified the modes of failure and patterns of wear of 11 Mittelmeier and 11 Ceraver-Ostal retrieved alumina-alumina hip prostheses with reference to the corresponding clinical and radiological histories. Macroscopic wear was assessed using a three-dimensional co-ordinate measuring machine. Talysurf contacting profilometry was used to measure surface roughness on a microscopic scale and SEM to determine mechanisms of wear at the submicron level. The components were classified into one of three categories of wear: low (no visible/measurable wear), stripe (elliptical wear stripe on the heads and larger worn areas on the cups) and severe (macroscopic wear, large volumes of material lost). Overall, the volumetric wear of the alumina-alumina prostheses was substantially less than the widely used metal and ceramic-on-polyethylene combinations. By identifying and eliminating the factors which accelerate wear, it is expected that the lifetime of these devices can be further increased.

Adolescent↗
PubMed2000

Behavior of human osteoblastic cells on stoichiometric hydroxyapatite and type A carbonate apatite: role of surface energy.

To determine the role of physicochemical characteristics of the surface of dense ceramics on osteoconduction, we studied the proliferation and differentiation of human trabecular (HT) osteoblastic cells, extracellular collagenous matrix production, and biologic apatite formation on stoichiometric hydroxyapatite (HA) and type A carbonate apatite (CA). The surface physicochemical characteristics (composition, roughness) of HA and CA carefully were determined by Fourier-transformed infrared, X-ray photoelectron, and Raman spectroscopies, and by FTIR microscopy, before and after cell culture. On both HA and CA substrates, HT cells attached, proliferated, and differentiated. Cell proliferation did not differ on HA and CA. However, the initial cell attachment and spreading of HT cells were much lower on CA compared to HA. Physicochemical and biologic analyses showed that collagenous synthesis by HT cells after 6 weeks of culture also was lower on CA than on HA. Quantitative histologic analysis confirmed that the collagenous matrix production was lower on CA than on HA. Measurement of wettability showed that the polar interaction energy with water was significantly lower on CA than on HA. The lower cell attachment and collagen production on CA compared to HA clearly were related to the low affinity of HT cells for the CA surface. This study shows that the surface energy of the biomaterial greatly influences the initial cell attachment and spreading of human osteoblastic cells at the surface and affects collagenous matrix deposition on the biomaterial. This suggests that the enhancement of polar components of the surface of dense biomaterials may improve osteoblastic cell attachment and, thereby, osteoconduction.

Apatites↗
PubMed2000

Bioactivity of sol-gel bioactive glass coated alumina implants.

Alumina on alumina total hip arthroplasty has been in use for more than 25 years with encouraging results. However, an improvement of the alumina/bone interface still is required. The objective of this study was to investigate the in vitro and in vivo osteoconductive properties of sol-gel bioactive glass coated alumina implants. Two sol-gel glass compositions (58S Bioglass(R) and 77S Bioglass(R)) were used as coatings on alumina substrates and implanted in a rabbit model. The 58S sol-gel coating was employed in two configurations, single (A58S1) and double layer (A58S2). SEM analysis after one week in simulated body fluid revealed small crystals assumed to represent the initial phase of hydroxyapatite formation, whereas no clear conclusion could be drawn from Fourier transform infrared spectroscopy data. The percentage of bone in direct contact was greater for coated implants when compared to bulk alumina implants (p <0.001). In the case of A58S1 implants, bone percentage significantly increased from 45.1% after 3 weeks up to 87. 8% after 24 weeks of implantation (p = 0.0004). The presence of osteoid tissue, related to an aluminum release from the alumina substrates, was greatly diminished when compared to melt-derived glass-coated alumina implants.

Aluminum Oxide↗
PubMed2000

Ceramic/ceramic total hip arthroplasty.

Alumina-on-alumina total hip arthroplasty has been used for 30 years, mainly in Europe. The theoretical advantages of this combination are represented by its remarkable sliding characteristics, its very low wear debris generation, and its sufficient fracture toughness. These advantages are achieved if the material is properly controlled with high density, high purity, and small grains. The authors summarize the results obtained with ceramic/ceramic total hip arthroplasty. Information is provided about in vivo behavior regarding wear debris characterization and quantification, and histological tissue examinations for inflammatory reactions, which were not encountered except when alumina debris was mixed with metal or cement. Modification of socket fixation resulted in improved clinical outcomes. With a press-fit metal shell and an alumina liner utilized for 10 years, the results are excellent especially in a young and active population. Alumina-on-alumina seems at the moment to be one of the best choices when a total hip arthroplasty has to be performed in young and active patients.

Aluminum Oxide↗
PubMed2000

Tissue-engineered bone regeneration.

Bone lesions above a critical size become scarred rather than regenerated, leading to nonunion. We have attempted to obtain a greater degree of regeneration by using a resorbable scaffold with regeneration-competent cells to recreate an embryonic environment in injured adult tissues, and thus improve clinical outcome. We have used a combination of a coral scaffold with in vitro-expanded marrow stromal cells (MSC) to increase osteogenesis more than that obtained with the scaffold alone or the scaffold plus fresh bone marrow. The efficiency of the various combinations was assessed in a large segmental defect model in sheep. The tissue-engineered artificial bone underwent morphogenesis leading to complete recorticalization and the formation of a medullary canal with mature lamellar cortical bone in the most favorable cases. Clinical union never occurred when the defects were left empty or filled with the scaffold alone. In contrast, clinical union was obtained in three out of seven operated limbs when the defects were filled with the tissue-engineered bone.

Animals↗
PubMed2000

Evolution of alumina-on-alumina implants: a review.

The use of alumina-on-alumina sliding surfaces for total hip replacement is becoming increasingly popular. The author has reviewed the 30-year history of this material. Technical aspects such as the quality of the material, quality of the design, and the risk of fracture are presented. The clinical results observed by the author are summarized with additional references to the results of other surgeons. The overall conclusion is that this material is very safe if all the quality requirements are met. The extremely low generation of wear debris and the excellent biologic tolerance of the material impart a long lifetime to the implant in young and active patients.

Aluminum Oxide↗
PubMed2000

Alumina-on-alumina total hip prostheses in patients 40 years of age or younger.

To avoid the consequences of polyethylene wear in a high-risk population, 128 alumina-on-alumina total hip arthroplasties have been done in 104 consecutive patients. The maximum age of patients was 40 years. The main preoperative diagnoses were osteonecrosis and sequellae of congenital hip dislocation (71% of the hips). The same titanium alloy cemented stem was implanted in all of the hips. Four types of alumina acetabular component fixations were used: a cemented plain alumina socket (41 hips), a screw-in ring with an alumina insert (22 hips), a press-fit plain alumina socket (32 hips), and a press-fit titanium metal back with an alumina insert (33 hips). Eight patients (11 hips) died during the followup period. Sixteen revisions have been documented, 12 for acetabular aseptic loosening, three for bipolar loosening (two of which were septic), and one for unexplained pain. Eighty-eight hips in 74 patients have been followed up radiologically for 2 to 22 years. Wear was unmeasurable. Four additional sockets showed definite migration. The respective survival rates after 7 years were 94.1% for the cemented cup, 88.8% for the screw-in ring, 95.1% for cementless press-fit plain alumina socket and 94.3% for the metal-back press-fit component. The 10-year survival rate was 90.4% for the cemented socket and 88.8% for the screw-in ring. The 15-year survival rate was 78.9% for the cemented socket. Grafting was the only prognostic factor, with a survival rate of 62.6% after 10 years for the hips with a bone graft and of 90.1% for hips without a graft. The alumina-on-alumina bearing surfaces seem to be a valuable alternative to the standard metal-on-polyethylene system for young patients. However, an improvement in socket fixation is required to lengthen the life span of the prosthesis to match the life expectancy of this demanding population.

Adolescent↗
PubMed2000

Wear of alumina-on-alumina total hip arthroplasties at a mean 11-year followup.

The surface topography of 11 alumina-on-alumina hip arthroplasties retrieved for aseptic loosening at a mean 11-year followup was investigated. Macroscopic wear was assessed using a coordinate measuring machine. Microscopic wear features were evaluated by Talysurf analysis. Scanning electron microscopy was used to look at the alumina microstructure. Components were classified into three groups: (1) low wear with no sign of wear and average arithmetic roughness values below 0.05 microm; (2) stripe wear with a visible oblong worn area on the femoral heads and penetration rates below 10 microm/year; and (3) severe wear with a visible loss of material on both components, showing total roughness values as much as 4 microm and maximum penetrations higher than 150 microm. Alumina quality assessed by grain size measurements and porosity percentages improved progressively from 1977 to 1988. This resulted in a correlated decrease of the microscopic wear magnitude. However, on a macroscopic scale, factors responsible for either a load increase (weight, young age, and male gender) or impairment in the load distribution over the component surfaces (large grain size, nonoptimal initial cup inclination, and cup migration and/or tilting) increased the penetration rates.

Adolescent↗
PubMed2000

Press-fit metal-backed alumina sockets: a minimum 5-year followup study.

Two hundred thirty-four consecutive alumina-on-alumina hip replacements using a press-fit metal-backed socket, performed on 214 patients (98 women, 116 men) have been reviewed. These included 201 primary procedures and 33 revision procedures. The median age of the patients at the time of surgery was 62 years (range, 21-83 years). Fourteen patients (16 hips) died from unrelated causes. Eleven patients (11 hips) underwent a total hip arthroplasty revision for recurrent dislocation (one hip), deep infection (two hips), fracture of alumina femoral head (one hip), persistent hip pain (one hip) and aseptic loosening (six hips). The survival rate after 9 years was 93.4% when revision of the prosthesis was considered the end point, and 97.4% if revision of the prosthesis for aseptic loosening was considered the end point. Results were assessed in the surviving patients with a minimal 5-year followup (170 patients, 184 hips). At the median followup of 7.8 years, the average Merle d'Aubigné and Postel score had improved from 11.9- to 17.7. Results were graded as excellent in 148 hips (80.5%), very good in 31 hips (17%), good in two hips (1%), and fair in three hips (1.5%). Radiologic data were documented for 134 patients (143 hips). Three sockets (2%) had a complete and nonprogressive radiolucent line less than 1-mm thick, one stem (0.7%) had lucencies involving five zones, and two stems (1.4%) had isolated femoral osteolysis. Neither component migration nor acetabular osteolysis were detected. A press-fit metal-backed socket may offer a good solution for alumina socket fixation when combined with a careful surgical technique of implantation.

Adult↗