Ultrasons focalisés de forte intensité pour la thérapie transcrânienne du cerveau

A novel MR-guided brain therapy device operating at 1 MHz has been designed and constructed. The system has been installed and tested in a clinical 1.5 T Philips Achieva MRI. Skull bone distortions induced on the ultrasonic beam are corrected using the concept of time reversal focusing. Prior to the treatment, a 3D CT scan of the patient head is performed and used as entry parameters for three-dimensional finite differences simulations that compute the propagation of the wave field through the human skull. The simulated phase distortions are then used as inputs for transcranial corrections. Temperature elevations during the treatment are imaged using MRI thermometry thus ensuring the control and safety of this therapeutic approach. First experiments are performed on four human cadavers and the promising results allow us to envision a first clinical investigation of this therapeutic approach in a near future. First targeted applications correspond to the non-invasive treatment of brain metastases and neurologic disorders such as the essential tremor.     

Un estimateur de distributions ajusté pour une aide à la décision de la neutralité génétique des populations

The estimate of the neutrality of a population is often made from a single measurement based on simulations of random patterns. Disputed cases pose a problem regarding the decision-making about the neutrality of the study population. We propose in this paper to provide assistance to the decision of this problem by coupling a genetically neutral populations simulator to a fast adjusted non-parametric estimator of simulated distributions. The choice of the Epanechnikov kernel for the non-parametric method of estimating the kernel allows an analytical approach of the optimal bandwidth, which leads to an improvement in the complexity and therefore a gain in computing time. The fast and reliable estimation of simulated distributions allows to assess the credibility of the decisions about the neutrality of these populations. These results are illustrated by two Tunisian populations whose neutrality is not genetically determined.     

Développement d’un système de navigation guidé par l’image,pour la chirurgie de l’épaule : chirurgie augmentée de l’épaule

This study concerns the general problem of the treatment of shoulder degenerative or traumatic lesions, based on total or partial joint replacement (shoulder arthroplasty). With baby boomers, increasingly complaining of shoulder pain, the number of shoulder arthroplasties increased by 15% each year. This surgical procedure is very difficult and limited to the expert centers. The two main challenges for this surgery are the minimal surgical incision and the limited access to the operated structures. Moreover, the success of such procedure is related to optimal prosthesis positioning. So far, the existing optimization and guiding systems are now very limited, which is no longer acceptable. Some mechanical systems may enhance the prosthetic components orientation but do not ensure an implant positioning taking into account the bone stock because it is not visible during the surgery. Only the preoperative evaluation on CT images could enhance the final gesture. To meet strong demand and meet the limitations of current solutions, we propose innovative approaches to build a navigation system easy to use and fully automatic for shoulder surgery.     

L’analyse métabolomique par spectrométrie de masse: un nouvel outil pour la biochimie clinique ?

Metabolomics (large scale analysis of small organic compounds) becomes a promising tool in biological exploration. This tool is able to identify modifications in biofluids occurring as a consequence of a pathogenic process. It’ll be shown how to carry out metabolomic analysis as well as the technological progress in this field. Concrete applications will be commented and the principal limitations will also be discussed. These limitations have to be overcome in order obtain data usable by biologists and medical doctors.     

Les hétérochronies du développement : un outil pour l'étude de la variabilité et des relations phylétiques ?: Exemple de Nigericeras,Ammonitina du Crétacé supérieur africain

Ontogenetic heterochronies: a tool to study both variability and phyletic relationships? Example: Nigericeras, Ammonitina of the african Upper Cretaceous. The Nigericeras gadeni ontogenesis (Saharian Upper Cretaceous) is characterized by three ornamental stages: multi-tuberculate inner-whorls, ombilical bi-tuberculate medium-whorls, then finally smooth adult stage. Ontogenetic Heterochonies account for their adult variability, which extends between both paedomorphic (thick/ornamented) morphotype, and peramorphic (thin/smooth) morphotype. That species may take root in the older Pseudocalycoceras. A peramorphocline characterizes the evolution of these ammonites and their younger relatives, leading to different Nigerian and Nigerien, highly compressed taxa. Such morphologies seem to be related to shallow-water palaeo-environments. The general transgressive context leads to the progressive scarcity of their supposed ecological niches. To cite this article: P. Courville, C. Crônier, C. R. Palevol 2 (2003).     

Préserver la fertilité chez les adolescents traités pour un cancer. Le point de vue du psycho-oncologue

The question of fertility is a major concern for young adults successfully treated for cancer, which is why semen preservation should be proposed to all adolescent boys prior to treatment of a cancer. This proposal is part of the oncologist’s approach to prevent sequelae. To ensure that semen cryopreservation is conducted under good conditions and is accepted by the adolescent, it is important to have a good understanding of the psychopathology and behaviour of adolescents with cancer: their preoccupation with their body, their appearance, their sexuality, their relationships to their peers and to their parents, their value and narcissism, their identity. This helps the clinician to understand and overcome the various reasons for their difficulty (and to lessen the painful feeling of failure) or their reticence to perform semen cryopreservation: paralysed by the diagnosis of cancer, sexual inhibition, lack of understanding and ignorance, pessimism concerning outcome, incapacity to project into the future, poor relationship with parents, discredit of parenthood, fear of transmitting the cancer, etc. A good understanding of these elements can avoid an excessively rapid acceptance of a superficial opposition to this procedure that the patient could subsequently regret. Closer collaboration should be developed between oncology-haematology departments and CECOS units to provide suitable information material to adolescents, to improve the understanding of the specific psychology of adolescents, and to understand the parents’ positions.     

Phénoménologie de la subjectivité : Tatossian et la clinique psychiatrique

The human sciences are now celebrating the return of the Subject. However, as a form of resistance to science, the issue of subjectivity justifies a methodological resort to a phenomenological posture. This posture consists in “seeing” and “showing” the experience of foundations. In Arthur Tatossian’s distinction between Subject and subjectivity, the Subject carries out the synthesis of forms in which the subjectivity expresses and alienates itself. These forms include: the Self, the consciousness, the inner mind, etc. Subjectivity is what makes the Subject possible. Subjectivity is time, space, the body and the Other, and is shaped by time into a living present, by space into a common place, by the body into flesh, and by the Other as alterity. In psychiatric disorders, the patient fails to be a Subject. Whoever he or she is, a Self without subjectivity, as with a melancholic or a maniac, or subjectivity without Self, as with a schizophrenic, the issue of human identity arises. The central problem of the human condition, which is at the heart of psychiatric disorders, is the challenge of being a Self while retaining a degree of subjectivity. This in turn merges with another central problem: that of freedom. Subjectivity is the other face of freedom because it is the power to create meaning.     

Joseph-Pierre Pétrequin (1809–1876): chirurgien, anatomiste, historien de la médecine, fondateur de la Faculté médicale lyonnaise et son procédé chirurgical original pour la cure de la gangrène de la verge

Pétrequin was an outstanding anatomist, surgeon, medical historian, and founder of the Lyon School of Medicine. This article describes his scientific contribution with particular emphasis on his original surgical procedure for the treatment of penile gangrene.