Biomedical subjects

B Chretien-Marquet

Publications and source records attributed to B Chretien-Marquet.

6 recordsLinked to original sources

PubMed1999

Description of cutaneous excision and suture using a mathematical model.

Mathematical models are being developed at a fast rate in industry thanks to computer technology; they are used to simulate motion and deformation over time to test materials and objects in a virtual manner. These modeling techniques are being developed in medicine, but they remain, at this time, in the domain of biomechanical research. We report a mathematical model for cutaneous excision and suture, which we have used to predict the deformations and tensions that result when using four different forms of excision. The results are expressed in numerical and graphic form. The results obtained corresponded with our experience in dermatologic surgery. Uses and limits of this model are discussed.

Biomechanical Phenomena↗

PubMed1999

ICAM-3 and E-selectin endothelial cell expression differentiate two phases of angiogenesis in infantile hemangiomas.

Cellular adhesion molecules are newly identified mediators of angiogenesis. Infantile hemangiomas, characterized in the early stages by a proliferation of poorly differentiated vessels followed in the late stages by a vascular differentiation and regression of the tumor, represent an interesting model to study angiogenesis. We studied by immunohistochemistry the distribution of HLA-DR and three adhesion molecules ICAM-3, E-selectin and VCAM-1 on endothelial cells in different stages of vessel differentiation in infantile hemangiomas. We found high levels of ICAM-3 expression on proliferating vessels, while its expression was low or undetectable on well differentiated vessels. A different set of E-selectin antibodies showed a more heterogenous pattern of distribution and VCAM-1 antigens were found in both proliferating and differentiated vessels. HLA-DR expression on endothelial cells was inversely correlated to the vascular differentiation. Our results are consistent with the hypothesis that ICAM-3 plays a role in the early stages of vessel formation. Our results also suggest that variation of E-selectin and HLA-DR expression may be related either to vessel differentiation or may reflect the acquisition of an activated endothelial cell status.

Antigens, CD↗

PubMed1998

Advantage of the presence of living dermal fibroblasts within in vitro reconstructed skin for grafting in humans.

Methods for serial cultivation of human keratinocytes can provide large quantities of epidermal cells, which have the potential of restoring the vital barrier function of the epidermis in extensive skin defects such as burns. To investigate the value of combining an epidermis with a dermal component, fibroblasts originated from the superficial dermis were used to seed a collagen lattice as described by E. Bell (dermal equivalent). Beginning in 1981, we grafted 18 patients (burns and giant nevi) using 35 grafts 10 x 10 cm in size. In the course of this work, the original technique was modified and improved as experience was gained. We began by using small skin biopsy samples as a source of keratinocytes cultured on a dermal equivalent before grafting in a one-step procedure, but this gave poor cosmetic results, because of a nonhomogeneous epidermalization. We then chose to cover the graft bed using a two-step procedure. The first step consisted of grafting a dermal equivalent to provide a dermal fibroblast-seeded substrate for subsequent in vivo epidermalization by cultured epidermal sheets. Whatever the epidermalization technique used, a living dermal equivalent applied to the graft bed was found to reduce pain, to provide good hemostasis, and to improve the mechanical and cosmetic properties of the graft. A normal undulating dermal-epidermal junction reappeared by 3 to 4 months after grafting and elastic fibers were detectable 6 to 9 months after grafting. As a result of the biosynthesis of these products, the suppleness (e.g., elasticity) of the grafts was closer to that of normal skin than the cicatricial skin usually obtained with epidermal sheets grafted without the presence of living dermal cells. This rapid improvement of the mechanical properties of the graft could be attributed to the presence of fibroblasts cultured from the dermis and seeded into the collagen matrix.

Adult↗

PubMed1997

Staphylococcal necrotizing fasciitis in the mammary region in childhood: a report of five cases.

OBJECTIVE: Necrotizing fasciitis is a highly lethal soft tissue infection rarely reported in childhood. The initiating site is usually a local trauma or a surgical wound. We observed five cases of necrotizing fasciitis the initiating site for which was the mammary region and discuss their management. STUDY DESIGN: We describe these five patients and review the clinical characteristics of their presentation. RESULTS: Staphylococcal necrotizing fasciitis was observed in the mammary region in all five cases. Four children were newborn infants with a mammitis preceding the onset of necrotizing fasciitis. Surgical débridement was done only after the fourth day from onset of illness. All children were discharged in good condition after 1 month. Two have been followed until puberty, with destruction of the mammary gland in one case and good development in the other one. CONCLUSION: Mammitis may be the initiating event for necrotizing fasciitis in neonates. Necrotizing fasciitis is a life-threatening disease; patients require early intensive care, parenteral antibiotic therapy, and surgical débridement. In a few instances surgery can be carefully delayed until the necrotic area is more delineated if the condition is diagnosed early during disease evolution and appropriate treatment is instituted in intensive care units.

Anti-Bacterial Agents↗

PubMed1996

[Giant congenital blue nevus of the scalp].

INTRODUCTION: Blue nevi are small acquired melanocytic tumors. Two clinical forms are described, a fibrous form and a cellular form. Giant nevi are exceptional. CASE REPORT: We describe a patient with a giant blue nevus of the scalp. In addition to this congenital, noninvasive tumor the patient presented numerous cutaneous melanocytic nevi. The main lesion was removed by surgical exeresis followed later with reconstruction plasty. The histological examination of the surgical specimen showed an infiltrating blue cell nevi. After a 4-year follow-up, there has been no recurrence and no metastasis. DISCUSSION: There have been 11 cases of giant blue nevi reported in the literature. All were congenital lesions with polymorphous clinical and histological aspects. Fibrous forms are noninvasive and cellular forms have a potential for local invasion, whether shortly after birth or later with invasion of muscles, bone and meninges without intracerebral extension. Congenital blue nevi require early surgical exeresis.

Child, Preschool↗

PubMed1995

Rapid intraoperative distension using isotonic saline solution.

Rapid intraoperative expansion can provide a solution to certain losses of cutaneous substance. In some cases where this method proves useful, I have been able to obtain interesting results by using distension with saline. I would like to show the importance of this operating technique, as well as its limits and advantages.

Adolescent↗