Biomedical subjects
Publications and source records attributed to F Braye.
BACKGROUND: Injuries by airbags are seen more frequently as more vehicles are equipped. CASE REPORTS: 7 cases of burns by airbags are reported. Most of burns are second degree lesions located on upper extremity and trunk. DISCUSSION: Lots of components are implicated in airbag deployment. So, three types of burn are described: thermal, chemical and friction. The treatment is simple. But, omission could be potentially dangerous, especially alkali chemical keratitis.
Thousands of patients receive human tissue grafts every year. Developments in cell and tissue engineering have also increased considerably the number of available products of human origin. France has very strict regulations, in part stimulated by problems of public health and ethics that have emerged in recent years and also in part as a result of a report by the 'Inspection Générale des Affaires Sociales' on the removal and grafting of human tissues in May 1993. These have resulted in two laws on bio-ethics being passed, in July 1994, that are the basis of current legislation and represent the first steps in differentiating between organs and tissues or cells. Henceforth, the French legal framework covering tissues and cells of human origin has been increased to include a large number of legislative texts and regulations. The fundamental ethical principles that are consent, free donation, anonymity, no publicity and respect for public health have become a major ethical imperative that applies to all products originating from the human body including tissue and cells. In addition, specific provisions have been made covering: removal (conditions for removal and system for authorization); conservation, transformation, distribution, packaging, import and export of tissues and cells; and tissue and cell grafts. Finally, penal and administrative sanctions have been foreseen where there is non-compliance with these regulations.
In 1975, serial subculture of human keratinocytes was first described. Clinical application of this discovery was made possible after the preparation of these cells into epithelial sheets. In 1981, the earliest application of cultured autologous epithelia was made for the treatment of extensive third-degree burns. Although the most important advantage is the large surface area obtained from a relatively small biopsy of healthy skin from the patient, a disadvantage is the delay, which is too long, especially for the treatment of extensive deep burns. This delay leads to denutrition and infection of the burn wounds, which in turn risks the life of the patient and jeopardizes the engraftment of the cultures. More recently, allogenic cultured epidermis, obtained more quickly from donor skin, has been described in the treatment of leg ulcers, repair of skin donor site harvested for split thickness autograft, dermatological diseases and in second-degree burns, although limited to certain areas. In this last case, grafted cells act by stimulation of epithelialisation from the adnexal appendages. To be able rapidly to treat patients suffering extensive and deep second-degree burns, a bank of allogenic keratinocytes has been created, with due attention to safety and security. The paper demonstrates the advantages of using allogenic keratinocytes in the first phase of treatment of a 97% deep second-degree burn patient awaiting autologous cultured keratinocytes. The time required for complete healing achieved using such a strategy is compared with the results obtained after treatment using autologous sheets of two patients burnt on 80% and 82% of their total body area. The treatment of these two latter patients is relatively long and complicated by potentially lethal problems. In the 97% burnt patient, however, the clinical course is shorter and without complication. Moreover, autologous and allogenic cultured epithelia give good aesthetic results, without the mesh aspect obtained with a split-thickness autograft, and also without the discomfort for the patient of removing a sample of skin. Deep second-degree burns are an application of choice for the cultured epithelia, as the presence of the dermis avoids retractions responsible for functional complications usually observed in third-degree burns where dermis is absent. Because of the safety of the bank of allogenic keratinocytes, the treatment of extensive and deep second-degree burns has become safer and faster, with better functional and aesthetic results.
Elastic fibers form a complex network that contributes to the elasticity of connective tissues. Alterations in the elastic fiber network are involved in several disease affecting organs in which compliance of the connective tissue is essential: skin, main vasculature, lung, joints, muscle, and ligament. The aim of our work was to study the deposition, maturation, and organization of elastic fiber components in a dermal equivalent model consisting of collagen-GAG-chitosan seeded with fibroblasts. The influence of keratinocytes was studied in parallel, thus constituting a skin equivalent model. These models were examined by transmission electron microscopy (TEM) and by immunohistochemistry to determine the staining patterns of fibrillin-1 and elastin proteins representative of the microfibrillar framework and of the elastic fibers, respectively. After 2 mo of fibroblast culture in the dermal equivalent, elastin was undetectable, whereas fibrillin-1 staining was weak and microfibrils were infrequently observed by TEM. In the skin equivalent, fibrillin-1 and elastin were detected by immunostaining 15 d after epidermization and TEM revealed the typical structure and organization of the elastic network in the dermis, with elastin deposition on the microfibrillar scaffold. This in vitro skin equivalent model is to our knowledge the first in which elastic fibers have been detected, thus demonstrating the influence of keratinocytes on the maturation and organization of the elastic network.
This is a retrospective study of the combination of widely meshed autograft and autologous cultured keratinocytes. We used this method faced with the lack of allogenic skin, as an alternate to the Cuono method. Twelve children suffering extensive burn injury (deep burns of 60%+/-16 of the total body surface) underwent this grafting procedure. The surgical treatment consisted of an early surgical excision, with an immediate coverage by autografts as much as possible. When cultured epithelium was available, a large mesh autograft was applied and covered with cultured epidermis sheets during the same operative procedure. The rate of take was of 84% (+/- 12). No secondary graft loss was observed. This means of coverage appeared reliable and resistant. On average, this method allowed the epidermization of 30% (+/-9) of the total body surface of the children. The average hospital stay of the children was 64+/-20 days. All the children recovered to lead a normal life. The school delay after rehabilitation is one year. This technique is an alternative to Cuono's method when allografts are missing. The combination of autograft and autologous cultured epidermis sheets appeared more effective than one of these techniques applied alone, as if the suggested coupling induced a synergy.
Based on their experience in the reconstruction of burn sequelae acquired over the last decade in India and Africa, the authors try to define a number of elements applicable to every case and in every country: the importance of preparation of missions in the foreign country and in France, concerning material and all team personnel; the particular conditions of anaesthesia-intensive care; surgical criteria of efficacy, rapidity, simplicity and reproducibility. Full-thickness skin grafts and reliable local or regional flaps are the preferred techniques. The authors consider that there is no place for expansion prostheses and microsurgical free flaps in this setting.
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Osseointegration of porous calcium phosphate ceramics evolves in several stages once implanted. Histologic analysis has often been used to evaluate the mechanism of integration of this material. Histologic parameters can be completed by physical analysis to obtain a semiquantitative evaluation of the osseointegration process. The histologic observation of hydroxyapatite (HA)-ceramic-containing bone sections was associated with proton-induced X-ray emission (PIXE) analysis and the results obtained by both methods were compared. Porous HA-ceramic cylinders were implanted in cortical bone of sheep femurs for periods ranging from 2 to 36 weeks. Thick sections of the implant containing bone were made at the end of the implantation period. A scanning line with two proton impacts 0.5 mm apart was plotted from the edges of cortical bone across the implanted ceramic and the X-rays produced were determined. Calcium, phosphorus, zinc, strontium, and iron contents were measured. Following PIXE analysis, the sections were surface-stained and observed under a light microscope to define the osseointegration index. Two regions of the curves were identified for each element characterizing either the bone tissue or the ceramic. Zinc and strontium present in the bone tissue but absent from the ceramics appeared after the 8th and the 12th implantation weeks, respectively. Iron present in the implant decreased with time, and calcium and phosphorus contents tended to be the same at the end of the implantation period in both curve regions. Histologic observation showed that immature bone invaded the pores of the outer layer of the ceramic as early as 2 weeks after implantation. Ceramics were totally osseointegrated 20 weeks after implantation. Osseointegration was apparently still evolving as judged by the PIXE method when histologic integration was considered complete.
The osseointegration of porous calcium phosphate ceramics once implanted evolves in several stages. The mechanism of integration of such material usually is evaluated by histologic analysis. The trace elements present in bone can be detected in the ceramic and help to provide a semiquantitative evaluation of osseointegration. Two different methods of microanalysis, energy-dispersive spectrometry (EDS) and proton induced x-emission (PIXE) were used in this study to determine the appearance of trace elements (Zn, Sr, and Fe) present in bone at the implantation site containing the ceramic. Porous HA-ceramic cylinders were implanted in the cortical bone of sheep femurs for periods ranging from 2 to 36 weeks. Thick sections of the implant-containing bone were made at the end of the implantation period. A scanning line with proton or electron impacts 0.5 mm apart was plotted from the edges of the cortical bone across the implanted ceramic and the resulting x-ray spectra were determined. Following EDS analysis, the sections were surface-stained, observed under a light microscope, and the pore volume occupied by bone tissue was measured. The spectra obtained by PIXE method showed two regions for each element characterising either the bone tissue or the ceramic. Zinc and strontium present in the bone tissue, but absent from the ceramic, appeared 8 and 12 weeks after implantation, respectively. The concentration of iron present in the implant decreased with time. EDS showed no significant level of either element in the bone or the ceramic. Histologic observation revealed that immature bone invaded the pores of the outer layer of the ceramic as early as 2 weeks after implantation. The ceramics were totally osseointegrated 20 weeks after implantation, although ceramic degradation continued for longer. In this experiment, the PIXE method was apparently sufficiently sensitive for monitoring the amount of trace element appearing in bone-implanted material.
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We describe a method for fixation of condylar fractures using a Kirschner pin. A retromandibular approach is used. This protocol was evaluated in 12 consecutive patients.
Substituting the tissue of human organs with biomaterials is problematic. However, its importance and relevance justify all the efforts made. An interdisciplinary approach is required. We report on our study of a product for bone substitution. Coral is a natural product, the interest of which we have already demonstrated in our previous work. Following sterilization, natural coral was implanted in sheep femurs. We regularly extracted the implants from the femurs to study the kinetics of elemental mineral transformation of the bone substitutes. For the first time ever, and thanks to the PIXE method (particles induced X-ray emission), we were able to measure the concentration of mineral elements at different time intervals after implantation over a whole cross-section. We found a discontinuity of the mineral elements (Ca, P, Sr, Zn, Fe) at the interface between the implant and the receiver. This shows that the osseous attack is not global but, on the contrary, centripetal. Moreover, the fit of the concentration time course indicates that the kinetics of ossification are different for each atomic element and characterize a distinct biological phenomenon. Our analyses confirm the biocompatibility and the ossification of the implanted coral.
The Abbe-Estlander flap is a full-thickness lip-switch flap rotated from mid lower lip to fill defects of the upper lip. In 1872, Estlander emphasized the importance of this flap. Abbe, in 1898, was the first to switch a lower lip flap into the upper lip for a cleft deformity. The lip-switch flap is an arterialized flap, based on the constant inferior labial artery. This flap is widely used to repair the defects from cancer and traumatism or in repair of the cleft lip deformities.
Exposure of the Achilles tendon may be secondary to injury, trophic ulceration or surgical management of Achilles tendon rupture. We used peroneus brevis (PB) and flexor hallucis longus (FHL) muscle flaps to cover the Achilles tendon. The muscular portion of these muscles extends very distally, allowing their transposition to the Achilles region. PB and FHL are narrow (about 4 centimeters); the use of both muscles increases their possibilities of coverage. We used PB alone in one case and both muscles in four cases. In every case we obtained a good functional and cosmetic result. Various fascio-cutaneous flaps have been described for the reconstruction of the Achilles region. When there is an infection, muscle flaps are preferable to fascio-cutaneous flaps because they provide well vascularized tissue. We consequently suggest the use of PB and FHL to cover the Achilles tendon when it has been exposed for a long time or when it is infected. It seems especially indicated when skin necrosis occurs after surgical management of Achilles tendon rupture.
Coral and hydroxyapatite may be used as substitution biomaterials for bone grafts. In this work, we extracted the implants from the femora to study the kinetics of elementary mineral transformation of the osseous substitutes. The use of physical analysis methods such as PIXE (particle-induced X-ray emission) shows that coral and hydroxyapatite, after their implantation in vivo, reach a mineral composition comparable with that of bone. For the first time we have measured the concentration of mineral elements, at different time intervals after implantation, along a cross-section. The distribution according to mineral elements (Ca, P, Sr, Zn, Fe) in the implant, in the receiver site and also at the interface, showed that the kinetics of coral resorption was faster than that of hydroxyapatite; in the same way, the osseous attack was not global but, rather, centripetal.
Moebius syndrome is a congenital bilateral palsy of the sixth and seventh cranial nerves. It results a total absence of facial expression and a severe strabismus. Social life is greatly disturbed. Other anomalies may be associated, especially other cranial palsies and Poland syndrome. The etiology of this syndrome isn't clearly established. Stem necrosis secondary to a vascular deficiency is often admitted. We report two observations. We emphasize the importance of a complete maxillo-facial treatment including maxillo-mandibular anomaly. Both patient underwent orthognathic surgery. The first one for class II and the second for class III anomaly. One patient underwent a facial reanimation by temporal muscle transfer. Orthognathic surgery must be realized prior to facial reanimation. A correction of the strabismus is possible. Moebius syndrome is a rare (200 observations) but very severe malformation. Maxillofacial surgery is able to improve the morphological and relational aspect of Moebius syndrome.
Because of the potential severity of their residual deformities, burn injuries in infants justify an early management in specialized centres when they cover more than 5% of body surface and in every case when hands, face, or external genitalia are concerned. Cooling with cold water is the first aid treatment to be performed as early as possible after the injury. The treatment in specialized centres must be both general and surgical. General treatment includes fluid and electrolyte therapy, temperature control, appropriate nutrition and pain suppression. Pain suppression is a major part of the treatment and morphine must be largely used. Surgical treatment starts as soon as the patient arrives in the centre and is eventually performed under general anesthesia: all the burned areas are covered with occlusive dressings. Infections are prevented by systematic cultures and adjusted antibiotic therapy. A vigorous rehabilitation program must be instituted as soon as possible: massages, compressive clothes, splints, physical therapy, plastic surgery. Primary prevention by sustained parental education is important in order to reduce the frequency of burn injuries in infants.