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Biomedical subjects

D Mainard

Publications and source records attributed to D Mainard.

At least 19 recordsLinked to original sources
PubMed2003

Cartilage repair using new polysaccharidic biomaterials: macroscopic, histological and biochemical approaches in a rat model of cartilage defect.

OBJECTIVE: The present study aims at evaluating, in a rat model of cartilage defect, the potential of various polymers as filling and repair biomaterials. The macroscopic and histological observations are compared to biochemical parameters in order to appreciate the pertinence of the latter as suitable criteria in tissue engineering. METHODS: A hydrogel, consisting of hyaluronic acid (HA), covalently substituted by hydrophobic alkyl chains (HA12, HA18) and an alginate sponge, alone (Asp) or combined with HA (AHAsp) or combined with HA and chondrocytes (HYBsp) were evaluated. Cartilage lesions were drilled in femoral trochlea of rats. The analyses were performed on trochlea as well as on patella and condyles. RESULTS: Repairs achieved with hydrogels had a similar macroscopic appearance than those afforded by AHAsp and HYBsp. Best macroscopic and histological scores were obtained with HA18 and HYBsp in comparison with alginate group (P< 0.01 and P< 0.02 respectively). Biochemical evaluations confirmed the presence of similar amounts of proteoglycans in the repaired zones and in the controls, though with different DeltadiC4S/DeltadiC6S ratios and enhanced HA levels. CONCLUSIONS: Hydrogels or sponges proved to be colonized by cells synthesizing a matrix with a high HA content. The matrix obtained eventually turns hyaline and takes over the scaffold. The addition of HA and/or chondrocytes to Asp significantly improves the macroscopic and histological scores (P< 0.05 and P< 0.02 respectively). However, biochemical parameters are significantly different of those evaluated in native cartilage. The present study shows that only biochemical parameters allow to discriminate between various biomaterials in tissue engineering and are essential informations which should be taken into account in addition to macroscopic and histological observations.

Alginates↗
PubMed2002

Beta-tricalcium phosphate ceramic as a bone substitute in orthopaedic surgery.

Synthetic beta-tricalcium phosphate ceramic (Biosorb, S.B.M., Lourdes, France) was used as a bone substitute in 110 patients whose mean age was 48 (14-83) years. There was a wide spectrum of indications, and the material was used alone in 86, combined with a corticocancellous bone autograft in 22, and combined with a corticocancellous allograft in two. The patients were assessed clinically and radiographically. Incorporation of the ceramic was excellent in 30, good in 51, and fair in 26. There were no poor results. In three patients the implanted material was removed because of infection. Incorporation was good or excellent in about 75% of all 110 patients. We consider beta-tricalcium phosphate ceramic to be the substitute of choice for medium-sized bone defects.

Adolescent↗
PubMed2002

Modified shoelace technique for delayed primary closure of the thigh after acute compartment syndrome.

The authors report a case of acute compartment syndrome in the thigh in a 19-year-old man with multiple injuries including fracture of the femoral diaphysis. Decompressive fasciotomy was performed emergently. Complete progressive closure of the wound without split-thickness skin grafting was achieved using a modified shoelace technique: sutures were run inside wide drains placed in contact with the muscles and were then tightened over the skin. These drains enlarged the contact area between sutures and muscles, preventing damage to muscles.

Acute Disease↗
PubMed2002

Polydactyly of the foot. Literature review and case presentations.

Polydactyly is a fairly common congenital condition of the foot and is characterized literally by supernumerary toes (digit or metatarsal). The frequency of polydactyly varies widely among populations. It may be an isolated condition or part of a congenital syndrome. Polydactyly is generally classified into three major groups: medial ray (preaxial), central ray and lateral ray (postaxial). The duplication may appear at the distal and middle phalanges or at the whole digit and metatarsal. The complexity of the deformity ranges from a simple soft-tissue problem to a completely developed accessory ray. Careful clinical and radiographic evaluation should be made prior to treatment to achieve good functional and cosmetic results. Most cases are treated during childhood before walking age. Adult cases are more rare, and surgical management of the deformity is still debated. Nevertheless, surgery can be performed at any age as in our series with good results.

Adult↗
PubMed2001

15-Deoxy-delta12,14-PGJ2, but not troglitazone, modulates IL-1beta effects in human chondrocytes by inhibiting NF-kappaB and AP-1 activation pathways.

The activation of peroxisome proliferator-activated receptor gamma (PPARgamma) has been shown to inhibit the production and the effects of proinflammatory cytokines. Since interleukin-1beta (IL-1beta) directly mediates cartilage degradation in osteoarthritis, we investigated the capability of PPARgamma ligands to modulate IL-1beta effects on human chondrocytes. RT-PCR and Western blot analysis revealed that PPARgamma expression was decreased by IL-1beta. 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2), in contrast to troglitazone, was highly potent to counteract IL-1beta-induced cyclooxygenase-2 and inductible nitric oxide synthase expression, NO production and the decrease in proteoglycan synthesis. Western blot and gel-shift analyses demonstrated that 15d-PGJ2 inhibited NF-kappaB activation, while troglitazone was ineffective. Although 15d-PGJ2 attenuated activator protein-1 binding on the DNA, it potentiated c-jun migration in the nucleus. The absence or the low effect of troglitazone suggests that 15d-PGJ2 action in human chondrocytes is mainly PPARgamma-independent.

Active Transport, Cell Nucleus↗
PubMed2001

Sodium alginate sponges with or without sodium hyaluronate: in vitro engineering of cartilage.

Studies are underway to design biosystems containing embedded chondrocytes to fill osteochondral defects and to produce a tissue close to native cartilage. In the present report, a new alginate three-dimensional support for chondrocyte culture is described. A sodium alginate solution, with or without hyaluronic acid (HA), was freeze-dried to obtain large-porosity sponges. This formulation was compared with a hydrogel of the same composition. In the sponge formulation, macroscopic and microscopic studies demonstrated the formation of a macroporous network (average pore size, 174 microm) associated with a microporous one (average pore size, 250 nm). Histological and biochemical studies showed that, when loaded with HA, the sponge provides an adapted environment for proteoglycan and collagen synthesis by chondrocytes. Cytoskeleton organization was studied by three-dimensional fluorescence microscopy (CellScan EPR). Chondrocytes exhibit a marked spherical shape with a nonoriented and sparse actin microfilament network. Type II collagen was detected in both types of sponges (with or without HA) using immunohistochemistry. In conclusion, the sponge formulation affords new perspectives with respect to the in vitro production of "artificial" cartilage. Furthermore, the presence of hyaluronate within the alginate sponge mimics a functional environment, suitable for the production by embedded chondrocytes of an extracellular matrix.

Alginates↗
PubMed2000

The structure of the cartilaginous end-plates in elder people.

Low back pain is the leading cause of work-related disability. Degeneration of the intervertebral disc (IVD), the boundaries of which with age-related changes remain obscure, is considered to be its most important cause. The cartilaginous end-plate (CEP) is the anatomic boundary of the IVD. Since the latter is avascular in adults, the CEP is supposed to play a key role in the metabolism of the IVD. Consequently, it has been postulated that the decrease in permeability of the CEP is the main cause of degeneration of the disc. However, the permeability depends at least partially on the morphologic state of the CEP. Little is known about the age-related changes of the CEP compared to those of the IVD. The objectives of the study were to examine the CEP at different ages, to classify the age-related changes in both the CEP and IVD, and to compare them. The intervertebral discs of the five levels of ten human lumbar spines were collected from cadavers aged from 47 to 78 years, and studied macroscopically and microscopically. Morphologic features of the CEP (thickness, IVD/CEP length ratio, degree of calcification, marrow contacts, CEP-VB and CEP-IVD separations) were measured. Morphologic grades were assigned for both the CEP and the IVD. No significant differences were found with regard to these features in the different age-groups. On the other hand, no significant correlation was found between the morphologic grade of the CEP and that of the IVD, suggesting that the importance of the CEP in disc degeneration may be debatable.

Aged↗
PubMed2000

[Filling of bone defects with tricalcium phosphate beta in traumatology].

AIM OF STUDY: Synthetic bone substitutes like calcium phosphate ceramics have been used in orthopaedic surgery for several years. The aim of this study was to assess the results of the use of tricalcium phosphate beta for filling bone defects in trauma cases. PATIENTS AND METHOD: beta tricalcium phosphate was used in 24 trauma cases. The GESTO classification (Association pour l'étude des Greffes et Substituts Tissulaires en Orthopédie) and a qualitative scale were used to estimate the integration. RESULTS: With a mean follow-up of 20 months, integration was excellent in 41.2%, good in 29.2% and moderate in 17.4%. No fibrous encapsulation was observed around the implants in any case. Sepsis occurred in 3 cases with open fractures. CONCLUSION: beta-Tricalcium phosphate seems in our experience to be an excellent bone substitute for filling bone defects in trauma cases.

Adult↗
PubMed2000

Influence of trauma induced by judo practice on postural control.

Although high-level sports develop specific physiological and sensorimotor abilities involved in balance control, they also increase the risk of injuries. The influence on postural control of lower limb trauma induced by judo practice was examined in healthy and previously injured judoists (PIJ). During static and dynamic tests, performed with or without vision, PIJ achieved the best performances in maintaining proper balance, except for those with the most severe antecedents of trauma. The severity of the pathology appeared to be the most important parameter prejudicial to balance control while the location, frequency and diversity of trauma had only a modest impact. This shows that PIJ develop excellent sensory and cognitive adaptation abilities to constraints involving new patterns of compensation and of body scheme.

Adaptation, Physiological↗
PubMed2000

The role of 3D-microscopy in the study of chondrocyte-matrix interaction (alginate bead or sponge, rat femoral head cap, human osteoarthritic cartilage) and pharmacological application.

The potentialities of a new non-invasive optical scanning microscopy technique were evaluated through 3D analysis of chondrocyte-matrix interactions. Five different 2D or 3D culture systems were used: (1) MonoLayer (ML) of human chondrosarcoma cell line; (2) rat or human chondrocytes encapsulated in Alginate Bead (AB); (3) human chondrocytes encapsulated in Alginate Sponge (AS); (4) Rat Femoral Head Cap (RFHC); (5) slices of knee human Osteoarthritic Cartilage (HOAC). Chondrocytes ML, AB, RFHC were incubated for 24 h in vitro in the presence of recombinant human interleukin1-beta (rhIL1-beta) and the effects on cytoskeleton organisation (F-actin filament), Focal Adhesion Kinase (FAK) expression (tyrosine kinase), collagenase B expression (metalloprotease) were studied. Furthermore, the production of intracellular IL1-beta by LPS- or rhIL1-beta-stimulated chondrocytes was shown to be partly suppressed by rhein (active metabolite of diacerhein) in all culture systems. This high resolution light microscopy gave complementary information that could be important for a better understanding of the interaction of chondrocytes with the extracellular matrix in a variety of culture devices.

Actins↗
PubMed2000

[Quality of life assessment one year after total hip or knee arthroplasty].

PURPOSE OF THE STUDY: The development of quality of life (QOL) instruments has made it possible to obtain an objective assessment of the impact of surgical procedures taking into consideration the physical, psychological and social aspects of the patient's everyday activities. The aim of this work was to evaluate the short-term and long-term course of QOL after total hip arthroplasty (THA) and total knee arthroplasty (TKA). MATERIALS AND METHODS: This study included a prospective multicentric cohort of patients with a first intention indication for degenerative bone and joint disease. Clinical assessment was obtained preoperatively and 6 weeks, 6 months and 12 months postoperatively. The Merle d'Aubigné and Harris scores were determined for THA and the Hospital Special Surgery score for TKA. Clinical data (pain, walking distance), and QOL scores [French version of the Nottingham Health Profile (NHP) and the French version of the Arthritis Impact Measurement Scale 2 (AIMS2)] were also obtained. RESULTS: One hundred twenty-three patients had a THA (mean age 62 years) and 60 had a TKA (mean age 68 years). Preoperative clinical features were those commonly found in these populations. For THA, the 6-week, 6-month and 1-year assessments showed an improvement (2.7 and 2.8 points on the 0 to 10 NHP). For TKA, improvement came later and was less significant with 0.8, 1.8 and 1.5 point improvements. The AIMS 2 did not appear to be perfectly adapted to measure this dimension. Improvement in pain came earlier and was greater for THA than for TKA on all measurement scales. For THA, psychological capacity improved by 0.7, 1.4 and 1.5 points on the 0 to 10 AIMS 2 at 6 weeks, 6 months and 12 months respectively. For TKA, improvement was to the same order with 1.1 and 1.2 point improvements at 6 weeks and 6 months respectively. DISCUSSION: These findings confirm the clear improvement in QOL after THA and TKA, mainly due to physical and psychological dimensions. The QOL measurements allow comparisons with other surgical procedures in other fields. They provide supplementary information, notably concerning pain and are particularly useful in orthopedic surgery. The questionnaires are generally well accepted by the patients, particularly short self-administered questionnaires. They provide useful information on the efficacy of THA and TKA in terms of human and social costs and open new perspectives for analysis of prognostic factors for optimal QOL of operated patients.

Activities of Daily Living↗
PubMed1998

Separation and quantification by ion-association capillary zone electrophoresis of unsaturated disaccharide units of chondroitin sulfates and oligosaccharides derived from hyaluronan.

An analytical method has been developed for assay of unsaturated disaccharides of chondroitin sulfates and of oligosaccharides (tetra- and hexasaccharides) of hyaluronan, using ion-association capillary zone electrophoresis. Samples were applied at the anode (the usual polarity), using a borate buffer modified by an ion-pairing reagent, tetrabutylammonium (TBA) phosphate, and the effect of the concentration of the ion-pairing reagent on various electrophoretic parameters (electroosmotic flow, electrophoretic mobility of products, capacity factors) was observed. Increasing concentrations of the reagent led to a decrease of zeta potential, probably due to specific adsorption of the quaternary ammonium ion onto the capillary wall. The authors propose a mechanism of separation, in which anionic borate complexes are formed and interact with TBA ion inside the capillary tube. The capillary electrophoretic system described is potentially a powerful method for specific measurement of the concentrations in joint tissues of chondroitin 4-sulfate, chondroitin 6-sulfate, and hyaluronan, whose relative abundances may vary in various diseases or after local treatments with, for example, antiinflammatory drugs, chondroprotective agents, or orthopedic implants.

Chondroitin Sulfates↗
PubMed1998

Amyloid and non-amyloid carpal tunnel syndrome in patients receiving chronic renal dialysis.

OBJECTIVE: To determine the prevalence of amyloid deposits among patients with carpal tunnel syndrome (CTS) receiving dialysis, and to investigate the factors associated with amyloid and non-amyloid CTS. METHODS: Subjects for this prospective study were dialysis patients who underwent surgery for CTS in the same surgical unit between 1989 and 1997. CTS was diagnosed from clinical and electromyographic (EMG) findings. Systematic standard radiographs and laboratory data were also obtained. Surgical investigations included systematic macroscopic examination and biopsy of the epineurium, flexor retinaculum, synovium, and flexor tendon sheaths. Samples were stained for amyloid and examined by plain and polarized light microscopy, immunohistochemistry, and electron microscopy. RESULTS: Forty-one samples from 30 patients (11 bilateral cases) were examined. Amyloid deposits were found in 26 samples from 18 patients (7 M, 11 F). Fifteen samples from 12 patients (3 M, 9 F) showed no amyloid deposits. Amyloid CTS was statistically significantly associated with arthralgia and longterm dialysis [mean 13.3 (range 5.5-23) vs 7.5 yrs (range 3 mo-14 yrs)] in non-amyloid CTS. Flexor tenosynovitis and carpal bone erosion occurred more frequently in amyloid CTS. There were no statistically significant differences between the 2 groups in clinical, laboratory or EMG findings, type of dialysis membrane, or frequency of ipsilateral fistula. Only amyloid CTS was recurrent. CONCLUSION: Amyloid deposits were confirmed microscopically in 63.4% of patients. The relatively large number of cases of non-amyloid CTS without signs of dialysis associated arthropathy suggests that CTS is not a satisfactory criterion for diagnosis of dialysis arthropathy or beta2-microglobulin amyloidosis unless the presence of amyloid has been confirmed or duration of dialysis treatment has been at least 15 years.

Adult↗
PubMed1997

[Flatfoot].

The flat foot is a very frequent cause of consultation in podology. The lesion is rapidly fixed, and osteoarthrosis appears. The diagnosis is clinical. A podoscopic and radiographic examination is necessary to appreciate the evolutivity of the deformity. The treatment is almost conservative: the wearing of orthesis is often sufficient. The indications of the surgery are rare; sometimes it is possible to do plastic techniques (in particular on the posterior tibial tendon) but, when the foot is painful, the osteoarthrosis is present and it is necessary to do arthrodesis, in particular in the talonavicular joint.

Adolescent↗
PubMed1997

[Current treatment of static deformities of the great toe].

The modern techniques of treatment of the hallux valgus are founded on the biomechanic and permit to give again a good function of the big toe. The authors prefer the osseous methods and specially the phalangeal and metatarsal osteotomies. It is necessary also to do a lateral release of the metatarsophalangeal joint and an exostosectomy. The late results are good.

Adult↗