Biomedical subjects
Publications and source records attributed to F Petit.
Vacuum-Assisted Closure (VAC) technique has been used in the treatment of acute and chronic wounds. The authors report a case of large thoracic defect, where the VAC was used to cover an exposed Gore Tex prosthesis after the failure of a latissimus dorsi flap. The VAC managed to save the Gore Tex prosthesis before a delayed reconstruction.
The authors report the case of a complex defect of the penis in children. Vacuum-Assisted Closure therapy as been shown to be very effective in enhancing wound debridement and the rate of granulation tissue formation. Complete closure of this complex wounds was obtained with a bilateral scrotal flap.
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Hand and composite tissue allotransplantation (CTA) holds great potential for reconstructive surgery but its development is currently limited by the side-effects of the immunosuppressive drugs. Induction of specific tolerance, a situation where the recipient does not mount an immune response against the allograft but remains fully immunocompetent, holds exciting promise. Generation of mixed hematopoietic chimerism by infusing the recipient with donor bone marrow cells has been shown to induce tolerance without chronic immunosuppression. Genetic matching of the donor and the recipient is another option for transplanting composite tissues with only an initial course of immunosuppression. Experiments demonstrated long-term survival of musculoskeletal allografts between MHC-matched miniature swine. Finally, new immunosuppressive agents with a more targeted action will reduce side-effects and may prevent the development of chronic rejection. Skin-specific immunosuppression is particularly useful for limb transplants since skin, regarded as the most antigenic component, is easily accessible to topical or irradiation therapies.
By combining molecular biology and biochemical approaches, the dynamics of sulfate-reducing microorganisms (SRM) was investigated in the sediments of the Seine estuary (France). Both intertidal mixing-zone and freshwater mudflats were sampled during a 1-year period; the quantification of SRM was realized by using competitive polymerase chain reaction (PCR) based on dsrAB gene amplification, previously described by Leloup et al. (2004), and sulfate reduction rate (SRR) was determined via the SO4(2-) radiotracer method. Throughout the year, abundance of dsrAB genes and SRR were predominantly high in the top 15 cm of the sediment. A seasonal dynamic was observed; a predominance of activity was noted during the early summer, and seems to be mainly controlled by physical-chemical parameters (temperature and dissolved organic carbon concentration) and topographic evolution of the mudflat (erosion/deposit erosion).
UNLABELLED: Breast implant surgery is now regulated by health laws, which stopped concerns and debates about the safety of the implants in the 90'. After a 6 years ban, silicone gel-filled implants have been allowed by the Afssaps (a national health agency) in 2001, for use in France. The comeback of the silicone gel implants has been a breakthrough in the breast implant market. GOALS OF THE STUDY: Our goal was to assess breast implant use in France, from 1995 til 2004, a time of deep turmoil for breast implant surgery due to new regulations. METHODS: All manufacturers have been requested to participate in the study and send their confidential data regarding the number and type of implants sold yearly, from 1995 to 2004. RESULTS: Breast implant sales rose by 53% in 2001, and increase by +383% from 1995 to 2004. The total number of breast implants sold in 2004 reached about 61 800. Following the lift on their ban, silicon gel-filled implants became immediately first-choice implants (they represented 72% in 2001 and more than 97% of all implants sold in 2004); saline filled implants are now rarely used. Textured envelopes are more often used (they represented 73 to 97% between 1995 and 2004), and smooth envelopes represented about 15%. CONCLUSION: Health agencies in France and Europe would benefit from a better knowledge of the use and follow-up of breast implants. These are plastic surgeon' or scientific society' responsibilities. A national breast implant registry may be a useful tool to gather information, to improve long-term follow-up and to provide better care to women concerned themselves with breast implant surgery.
The deep inferior epigastric perforator flap (DIEP) is a variation of the transverse rectus abdominis myocutaneous flap (TRAM). This flap was used as a pedicled flap to reconstruct the pelvis and thigh region after resection for cancer (four cases). Various flaps have been described for covering theses tissue defects but we prefer this perforator flap for its many advantages. This flap is very reliable and generates minimal functional sequelae on donor site. This flap is useful to cover soft tissue defects after vascular and oncologic surgery, a situation that was rarely reported to our knowledge.
We described a colorimetric method to determine the biochemical phenotype of wild-type and mutated cytomegalovirus (HCMV) DNA polymerases by measuring the incorporation of digoxigenin-labelled nucleotides into the growing DNA chain. Mutations V715M and E756K, which are known to confer foscarnet-resistance, were used as controls. Mutation N495K and a combination of changes K415R and S291P, both observed in foscarnet-resistant isolates, were studied. The mutations were introduced by site-directed mutagenesis into wild-type gene UL54 cloned in an expression vector and then polymerases were synthesised by using a commercially available coupled transcription-translation system. The polymerase activity was measured with and without foscarnet. The activity of polymerases containing the V715M or E756K mutations was inhibited by foscarnet at concentrations 70- and 30-fold higher than that of wild-type polymerase, respectively. Change N495K and combination of K415R and S291P, induced a five- and ten-fold decrease in susceptibility to foscarnet, respectively. The results of this non-radioactive assay were consistent with those obtained with the conventional radioactive assay. Therefore, this novel phenotypic method could be useful for the characterisation of mutations that confer HCMV resistance to foscarnet.
Composite tissue allotransplantation is an emerging practice in the field of reconstructive surgery. Although still restricted to patients with major physical defects, it could be more widely practiced in the close future. The broadening of reconstructive surgery with "tissue reconstitution" depends on the functional results from the first hand allografts and from progress in immunotherapy. The mastery of microsurgery is a fundamental prerequisite to this activity and its development. Plastic surgeons will soon have to conceive, define, and master innovative surgical procedures for tissue restoration by microsurgical allotransplantation.
Tumors of salivary glands arise mainly from the parotid gland. Magnetic Resonance Imaging (MRI) is mandatory not only to localize precisely the tumor within the gland but also to differentiate between benign and malignant neoplasms, in competition with cytology in fine-needle aspiration biopsy. Tumors without risk of transformation, such as adenolymphoma, are not systematically operated on. Indications of roentgenotherapy and irradiation volumes depend on histologic type, localisation and size of the tumor.
Pathogenic human immunodeficiency virus (HIV)/Simian immunodeficiency virus (SIV) infection is associated with increased T-cell apoptosis. In marked contrast to HIV infection in humans and SIV infection in macaques, the SIV infection of natural host species is typically nonpathogenic despite high levels of viral replication. In these nonpathogenic primate models, no observation of T-cell apoptosis was observed, suggesting that either SIV is less capable of directly inducing apoptosis in natural hosts (likely as a result of coevolution/coadaptation with the host) or, alternatively, that the indirect T-cell apoptosis plays the key role in determining the HIV-associated T-cell depletion and progression to acquired immune deficiency syndrome (AIDS). Understanding the molecular and cellular mechanisms responsible for the disease-free equilibrium in natural hosts for SIV infection, including those determining the absence of high levels of T-cell apoptosis, is likely to provide important clues regarding the mechanisms of AIDS pathogenesis in humans.
The authors describe a new position of the patient that enables the surgeon to perform a bilateral and synchronous mammaplasty, without switching sides. The patient is first raised in the sitting position, then the thigh and leg holders of the operating table are spread out to a 45-60 degrees angle. The surgeon stands in between the thighs, where he faces the chest and can operate on the breasts. The entire operation is performed by the surgeon, approaching both breasts simultaneously without the need for switching positions. The direct and central access, along with the continuing visual control of the shaping, turns the operation into a simple and faster one with better control of the cosmetic result.
Eleven patients with glycogen storage disease type Ib (GSD Ib) were studied. Using a combination of single-strand conformation polymorphism (SSCP) analysis, restriction enzyme digestion and direct sequencing, we were able to identify 21/22 mutant alleles comprising 12 different mutations in the glucose-6-phosphate translocase gene (G6PT). Among these, one is a novel mutation of G6PT: 855T>C (L229P).
CD4+ T-cell death is a crucial feature of AIDS pathogenesis, but the mechanisms involved remain unclear. Here, we present in vitro findings that identify a novel process of HIV1 mediated killing of bystander CD4+ T cells, which does not require productive infection of these cells but depends on the presence of neighboring dying cells. X4-tropic HIV1 strains, which use CD4 and CXCR4 as receptors for cell entry, caused death of unstimulated noncycling primary CD4+ T cells only if the viruses were produced by dying, productively infected T cells, but not by living, chronically infected T cells or by living HIV1-transfected HeLa cells. Inducing cell death in HIV1-transfected HeLa cells was sufficient to obtain viruses that caused CD4+ T-cell death. The addition of supernatants from dying control cells, including primary T cells, allowed viruses produced by living HIV1-transfected cells to cause CD4+ T-cell death. CD4+ T-cell killing required HIV1 fusion and/or entry into these cells, but neither HIV1 envelope-mediated CD4 or CXCR4 signaling nor the presence of the HIV1 Nef protein in the viral particles. Supernatants from dying control cells contained CD95 ligand (CD95L), and antibody-mediated neutralization of CD95L prevented these supernatants from complementing HIV1 in inducing CD4+ T-cell death. Our in vitro findings suggest that the very extent of cell death induced in vivo during HIV1 infection by either virus cytopathic effects or immune activation may by itself provide an amplification loop in AIDS pathogenesis. More generally, they provide a paradigm for pathogen-mediated killing processes in which the extent of cell death occurring in the microenvironment might drive the capacity of the pathogen to induce further cell death.
Communication using images proves to be the superior way to persuade audiences. Thus, in cosmetic surgery, images are widely used to inform and to lure consumers. The superpower of visual communication is being bolstered by viewers' credulity, who never call into question the authenticity of photos as long as those photos are credible. Colorful digital images are broadcasted among scientific meetings, displayed in medical offices, and posted on the Internet. They generate a virtual world where cosmetic surgery is idealized: plastic surgeons are talented and handsome, operations are successful, and complications do not occur. We consider that digital imaging and the Internet should serve as a means to provide information that will ultimately strengthen the surgeon-patient relationship.
PURPOSE: Apoptosis during HIV infection has been evoked for ten years. The role of apoptosis during HIV infection have be confirmed by several authors but the exact relationships between viral replication, apoptosis and lymphocyte depletion remain to be clarified. CURRENT KNOWLEDGE AND KEY POINTS: HIV may induce apoptosis of infected but also of uninfected bystander CD4+ lymphocytes. Those two types of HIV induced apoptosis lie on different pathways. While Fas and FasL are involved in apoptosis of bystander cells, mitochondrial pathway is required for apoptosis of infected cells. Cytokines but also anti HIV drugs may modulate HIV-induced lymphocyte apoptosis. Morever while protease inhibitor influence HIV replication and then secondary apotosis of infected cells, they can also interfere with spontaneous apoptosis of lymphocyte beside the context of HIV infection. FUTURES AND PROJECTS: Apoptosis is thought to be one of the mechanism involved in CD4 T lymphocyte cell death during HIV infection. However relationships between apoptosis and HIV replication may be more complex. In fact it has been recently reported that while HIV replication induced lymphocyte apoptosis, apoptosis may in turn induced HIV replication in a loop amplification pathway
Studies of human immunodeficiency virus (HIV) and nonhuman primate models of pathogenic and nonpathogenic simian immunodeficiency virus (SIV) infections have suggested that enhanced ex vivo CD4 T-cell death is a feature of pathogenic infection in vivo. However, the relative contributions of the extrinsic and intrinsic pathways to programmed T-cell death in SIV infection have not been studied. We report here that the spontaneous death rate of CD4+ T cells from pathogenic SIVmac251-infected rhesus macaques ex vivo is correlated with CD4 T-cell depletion and plasma viral load in vivo. CD4+ T cells from SIVmac251-infected macaques showed upregulation of the death ligand (CD95L) and of the proapoptotic proteins Bim and Bak, but not of Bax. Both CD4+ and CD8+ T cells from SIVmac251-infected macaques underwent caspase-dependent death following CD95 ligation. The spontaneous death of CD4+ and CD8+ T cells was not prevented by a decoy CD95 receptor or by a broad-spectrum caspase inhibitor (zVAD-fmk), suggesting that this form of cell death is independent of CD95/CD95L interaction and caspase activation. IL-2 and IL-15 prevented the spontaneous death of CD4+ and CD8+ T cells, whereas IL-10 prevented only CD8 T-cell death and IL-7 had no effect on T-cell death. Our results indicate that caspase-dependent and caspase-independent pathways are involved in the death of T cells in pathogenic SIVmac251-infected primates.
Tissue allotransplantation is defined by the transfer of tissues harvested from a cadaveric donor (in a brain dead condition) and revascularized to a recipient subject. This is based on the mastery of microsurgical techniques and on the induction of a therapeutic immunosuppression for the recipient. The first allografts (flexor tendon systems, knees and femoral diaphysis, hands, nerves, larynx) opened the field of composite tissue allotransplantation (C.T.A.) in reconstructive surgery. Immunosuppressive agents are now efficient enough to prevent the rejection of the allografts. The first patients operated on did not suffer from major or irreversible complications, but some potential side-effects of the immunosuppression remain an obstacle to the development of allografts in reconstructive surgery. The early functional results of the allografts are encouraging but their long term evolution remains uncertain. Some immunological (the chronic rejection) or psychological (the refusal of the graft and of its constraints) phenomenon might curtail the functional, aesthetic and psychological result. Currently considered as an extreme solution to exceptional indications, C.T.A. represents a tremendous hope for the future of reconstructive surgery.