[Under the epidermis, the dermis, or how to interpret skin cultures?]. / Sous l'épiderme, le derme ou comment comprendre les cultures de peau?

After a brief review of the three basic principles of reconstruction of the skin (structure, antigenicity and function), the author presents the various skin culture techniques, tissue by tissue. He explains the main methods of reconstruction of natural or artificial dermal tissue and epidermal structures, and finally the in vitro simultaneous reconstruction of both tissues, dermis and epidermis; only this last technique can really be called "skin culture".

[Reconstruction of the nose in deep extensive facial burns]. / La reconstruction du nez dans les brûlures pan-faciales profondes.

The nose is in the medial portion of the face and is frequently injured in trauma of this area. Due to its situation its structure and shape, and its essential function, this organ is particularly exposed in the case of facial burns. These injuries, are usually associated with larger injuries, and frequently with systemic problems, such as respiratory problems. The authors describe nasal burns in the larger context of facial burns, and summarize recent data on this topic. They then recall the fascinating story of rhinopoiesis through the ages. The third part is devoted to their personal approach to reconstruction of the nose in severe panfacial burns, using a forehead flap with one or several tissue expanders.

Advantages of early burn excision and grafting in the treatment of burn injuries of the anterior cervical region.

Excision and grafting in deep partial and full skin thickness burns of the anterior cervical region in a series of 40 patients treated between 1982 and 1992 is reported. The advantages of surgical management of deep burns in this region in a single staged operation have proved its efficacy compared to the severe sequelae which appear when the standard conservation treatment is used. A comparative study of two groups of patients treated either by early excision and grafting (n = 19/40), or by delayed excision and grafting (n = 21/40) demonstrated the advantages of elective early excision and grafting with respect to: length of hospital care, complications and their severity, and surgical repair.

[Experimental study on a skin substitute. Artificial dermis epidermised by human keratinocytes]. / Etude expérimentale d'une substitut cutané. Derme artificiel épidermisé par des kératinocytes humains.

In patients with third-degree burns, plastic surgeons must meet emergent requirements for skin coverage. Conventional autografts do not provide enough substance to cover these patients, hence the interest of skin substitutes. The aim of our work is to achieve epidermization of an artificial dermis with a technique of culture of human keratocytes, thus producing in vitro a dermoepidermal skin substitute akin to normal skin, and to implant it in nude mice. Human keratocytes are grown in a definite medium (MCDB 153) on an artificial dermis based on type I and III collagen and glycosaminoglycans, and cross-linked with chitosan. Human keratocytes from thin skin were seeded on the artificial dermis after a last passage in culture fials. Cell density and the number of days in vitro were varied on patches of artificial dermis. After culture, the patches were transferred on nude mice. These were sacrificed on the 7th or 14th day. Cell recolonization of the artificial dermis was then studied, as well as the growth of the epidermis on deep-frozen histologic sections. Primary cultures on an artificial dermis did not show production of a satisfactory epidermis. In some animals grafted with artificial dermis epidermized in a secondary culture, we observed a structure similar to that of normal skin. This work allowed outlining the problems to slove and contemplating the solutions required to develop a total artificial skin.

[Kinetics and physiopathology of immune depression following severe burns. Experimental study. Benefits of early excision. Role of prostaglandins]. / Cinétique et physiopathologie de la dépression immunitaire après brûlure grave. Etude expérimentale. Bénéfice de l'excision précoce. Rôle des prostaglandines.

The data obtained in a rat model supports the following conclusions. There is a period of normal immune responsiveness surrounding day 6, in spite of peaks of immunosuppression before and after that time. The spleen in burned animals is hypertrophic. This is due to its role as a filter (necrotic particles seen in macrophages) and as a "germ reservoir" (spleen culture studies). Impairment of immune function in spleen cells is important since, before day 6, there is an inhibition of antibody production with no alteration in lymphocyte transformation. After day 6, both functions are impaired. Most important to the clinical treatment of burns, all of these phenomena are diminished or abolished by early removal of the burned tissue. The profile of immune depression in burned rats therefore seems to show two stages: before and after day 6. During the first stage, stress and prostaglandins from burned skin are probably the cause of immune depression: during the second stage burn toxins and prostaglandins from the spleen cells are probably the cause.

[Development of non-cellular dermis: a step towards a total artificial skin]. / Mise au point d'un derme acellulaire: un pas vers la peau artificielle totale.

In large cutaneous defects due to severe burns, dermal mesenchyme healing has to be controlled in order to avoid granulation tissue that rapidly leads to important contractures and hypertrophic scars. We report a study about the use of an artificial dermis made of human collagen (I and III) and several glycosaminoglycans. This artificial dermis was grafted on Sprague-Dawley rats after a 9 cm2 skin excision on the back. An identical control area was made just under it, on the same animal. The animals were killed on day 2, 7, 14, 21, 30 and different parameters were studied: clinical study, bacteriological study, histopathological appearance, scanning and transmission electron microscopy, immunological study, physical parameters, UV absorption. Direct and indirect cytotoxicity tests, performed on cell cultures showed no change in the morphology and of the growth of the keratinocytes or of the fibroblasts. A biocompatibility study showed on the early days (day 2, 7, 14) that adherence of artificial dermis to the underlying tissue was good. There was virtually no bacterial colonization. Ultrastructural study showed an important cellular colonization, with an inflammatory appearance at the beginning. After a while, fibroblasts appeared, with synthesis of neocollagen fibers as early as the second week. Histological study showed neovessels in the artificial dermis. Later (day 21, 30) the inflammation was less severe and the amount of endogenous collagen increased.(ABSTRACT TRUNCATED AT 250 WORDS)

[Metastatic Darier-Ferrand dermatofibrosarcoma. Review of the literature apropos of a case]. / Dermatofibrosarcome de Darier-Ferrand métastasé. Revue de la littérature à propos d'un cas.

We report the case of a 56-year old male patient with pulmonary, abdominal and pelvic metastases from a dermatofibrosarcoma (DFS) which had developed 23 years previously in the right scapulo-humeral region and had recurred twice after the first excision, in 1983. Surgery was only performed once. The most remarkable feature of the disease was the progressive transformation, with each recurrence, of a typical DFS into a poorly differentiated and highly malignant tumour, about as active as a fibrosarcoma. A review of the literature yielded 31 cases of histologically proven metastatic DFS. Although the actual incidence of metastases is difficult to determine with accuracy, their frequency may be estimated at 3 p. 100 (most probably a maximum figure). The disease spreads mostly through the blood, but also sometimes through the blood and lymph. However, since lymphatic involvement is rare the usefulness of lymph node excision is extremely doubtful. Pulmonary lesions are the most frequent ones, but various other organs may be affected, although this seldom applies to the liver. Following a first excision, metastases occur within 6 years on average (range: 1 to 33 years). This mean delay is superior to the mean follow-up period for most of the important series without metastases. The histopathological picture is usually one of typical DFS but in some cases, including ours, it is much less typical and may even be frankly malignant. A few reports mention the presence of histiocytic infiltrates associated with the fibroblasts. The prognosis in patients with metastases is particularly poor: in most of the cases reported the patient died within the year following the discovery of metastatic lesions. The very high progressivity of the secondary lesions contrasts with the slow course of the primary tumour. None of the treatments tried (surgery, radiotherapy, chemotherapy) has resulted in a significant prolongation of life. No correlation can be established between the occurrence of metastases and the following parameters taken together: patient's age and sex, tim elapsed between the appearance of the tumour and the date of exicision, and histological features of the initial tumour. The development and number of recurrences seems to be the most significant predictive factor as regards the risk of metastasis. The noxious role of incomplete and/or repeated surgery creating vascular breaks, disrupting the defense barriers and encouraging malignancy in some cases has been mentioned by most authors; it emphasizes the value of the widest possible initial surgery.(ABSTRACT TRUNCATED AT 400 WORDS)

Immunity of the burned patient. An overview.

The study of mortality in severe burns shows very clearly that most patients die because of septic problems. Surgery and intensive care in burn patients are actually well established, but the fight against infection and septicemia is still difficult. The risk arises due to poor host defence, leading to an unfair struggle and very often ending in death. Today it has become necessary for every burn surgeon and plastic surgeon to understand why this immune depression occurs and how it can be prevented or treated.

The beneficial effect of early excision on clinical response and thymic activity after burn injury.

Catabolic response and immunodepression were studied in guinea pigs with scald burns that were excised on day 1 postburn and those that were scald burned but unexcised. Weight gain returned to normal by day 6 in the excised group but remained depressed in burned but unexcised animals whose wounds were untreated, or in unexcised animals whose wounds were treated by topical silver sulfadiazine. Thymic DNA synthesis returned to normal by day 6 in the excised group but remained depressed in the unexcised group. Plasma and thymic-free cortisol returned to normal by day 6 in the excised group but remained markedly elevated in the burned, unexcised animals. These studies indicate early excision and early wound closure reduce the catabolic response and immunodepression of guinea pigs following burn injury.

Severity and prognosis after early excisions from one to twenty percent of the body surface area.

The authors review 101 small and medium early excisions with immediate grafting. They study several parameters concerning the severity of the burn, the time and the duration of the surgical procedure, the blood losses, the effect on the protidemia during the shock period, the duration of the hospital care, the septicemic risk, the mortality, and the functional and cosmetic results. They come to the conclusion that, under 15% of the body surface area, early excision can be done at one single operation with hardly any risk, and that it is better to perform it as soon as possible (before 12 hours if possible). With a good splinting and a daily rehabilitation, the cosmetic and functional results are very satisfactory.

[Early respiratory involvement in burns. Mechanism and prognostic significance]. / L'atteinte respiratoire précoce chez le brulé. Mécanisme et signification pronostique.

A retrospective study, on 87 flame burn patients, of arterial Pa02, chest X-ray and lactic dehydrogenase isoenzyme III revealed the very early onset (before the 24th hour) of severe respiratory problems. This involvement, with a severe prognostic significance, appears to be much more closely related to the extent of the cutaneous burn than to the inhalation of fumes or vapours, and seems to fall into the more general category of "post-aggression lung".

Action of cholecystokinin and caerulein on the rabbit sphincter of Oddi.

The action of cholecystokinin (CCK) and caerulein upon the rabbit sphincter of Oddi was investigated by electromyography, manometry and measuring of the flow. Intravenous injection of CCK resulted in a marked rise of the sphincter activity with a maximum at the 1st min and return to the basal level at the 10th min. Injection of increasing doses of hormone showed that the effect was proportional to the logarithm of the dose. The same results were obtained with caerulein. Parallely, CCK provoked a rise of the biliary pressure also proportional to the logarithm of the dose and a reduction to the biliary flow. The discrepancies between these results and some other experiments are discussed. It is concluded that, in the rabbit, CCK increases the activity of the sphincter of Oddi.