Économie et géographie de l’agriculture

Joseph Klatzmann, directeur d’études Les pièges de la statistique L’enseignement a porté, comme les années précédentes, sur les pièges de la statistique, de toutes natures et dans tous les domaines. La méthode a consisté à faire réfléchir les étudiants sur des exemples trouvés dans des journaux, des articles ou des ouvrages. Un cas typique d’erreur grossière est celui du titre d’article faux parce qu’on a voulu le raccourcir : « la productivité a diminué dans l’industrie » au lieu de « le tau..

Économie et géographie de l’agriculture

Joseph Klatzmann, directeur d’études Les pièges de la statistique Pour attirer l’attention des étudiants sur les très nombreux problèmes d’interprétation des statistiques, on les fait réfléchir sur des exemples réels, tirés principalement de la presse, d’ouvrages et d’autres médias. Dans la première période, les exemples soumis à la réflexion des étudiants ont été classés en fonction des différents types de pièges ; dans la deuxième, ils l’ont été par matières : démographie, économie, etc. Un..

Économie et géographie de l’agriculture

Joseph Klatzmann, directeur d’études Les pièges de la statistique Un moyen efficace (il y en a aussi d’autres) d’informer les étudiants de tous les pièges dont ils doivent se méfier en lisant des données statistiques est de les faire réfléchir sur des articles de presse et des extraits d’ouvrages. Cette analyse a aussi pour but d’attirer leur attention sur les précautions à prendre lorsqu’ils doivent eux-mêmes présenter des statistiques. Voici quelques exemples des problèmes qui ont été discu..

Statistique appliquée

Jacques Sapir et Joseph Klatzmann, directeurs d’étudesRené Padieu, École des mines et Michel Louis Lévy, INSEE Compte rendu non communiqué

Contribution of Intrinsic Reactivity of the HIV-1 Envelope Glycoproteins to CD4-Independent Infection and Global Inhibitor Sensitivity

Human immunodeficiency virus (HIV-1) enters cells following sequential activation of the high-potential-energy viral envelope glycoprotein trimer by target cell CD4 and coreceptor. HIV-1 variants differ in their requirements for CD4; viruses that can infect coreceptor-expressing cells that lack CD4 have been generated in the laboratory. These CD4-independent HIV-1 variants are sensitive to neutralization by multiple antibodies that recognize different envelope glycoprotein epitopes. The mechanisms underlying CD4 independence, global sensitivity to neutralization and the association between them are still unclear. By studying HIV-1 variants that differ in requirements for CD4, we investigated the contribution of CD4 binding to virus entry. CD4 engagement exposes the coreceptor-binding site and increases the “intrinsic reactivity” of the envelope glycoproteins; intrinsic reactivity describes the propensity of the envelope glycoproteins to negotiate transitions to lower-energy states upon stimulation. Coreceptor-binding site exposure and increased intrinsic reactivity promote formation/exposure of the HR1 coiled coil on the gp41 transmembrane glycoprotein and allow virus entry upon coreceptor binding. Intrinsic reactivity also dictates the global sensitivity of HIV-1 to perturbations such as exposure to cold and the binding of antibodies and small molecules. Accordingly, CD4 independence of HIV-1 was accompanied by increased susceptibility to inactivation by these factors. We investigated the role of intrinsic reactivity in determining the sensitivity of primary HIV-1 isolates to inhibition. Relative to the more common neutralization-resistant (“Tier 2-like”) viruses, globally sensitive (“Tier 1”) viruses exhibited increased intrinsic reactivity, i.e., were inactivated more efficiently by cold exposure or by a given level of antibody binding to the envelope glycoprotein trimer. Virus sensitivity to neutralization was dictated both by the efficiency of inhibitor/antibody binding to the envelope glycoprotein trimer and by envelope glycoprotein reactivity to the inhibitor/antibody binding event. Quantitative differences in intrinsic reactivity contribute to HIV-1 strain variability in global susceptibility to neutralization and explain the long-observed relationship between increased inhibitor sensitivity and decreased entry requirements for target cell CD4

Progress in gene therapy for neurological disorders

Diseases of the nervous system have devastating effects and are widely distributed among the population, being especially prevalent in the elderly. These diseases are often caused by inherited genetic mutations that result in abnormal nervous system development, neurodegeneration, or impaired neuronal function. Other causes of neurological diseases include genetic and epigenetic changes induced by environmental insults, injury, disease-related events or inflammatory processes. Standard medical and surgical practice has not proved effective in curing or treating these diseases, and appropriate pharmaceuticals do not exist or are insufficient to slow disease progression. Gene therapy is emerging as a powerful approach with potential to treat and even cure some of the most common diseases of the nervous system. Gene therapy for neurological diseases has been made possible through progress in understanding the underlying disease mechanisms, particularly those involving sensory neurons, and also by improvement of gene vector design, therapeutic gene selection, and methods of delivery. Progress in the field has renewed our optimism for gene therapy as a treatment modality that can be used by neurologists, ophthalmologists and neurosurgeons. In this Review, we describe the promising gene therapy strategies that have the potential to treat patients with neurological diseases and discuss prospects for future development of gene therapy

Présentation

Klatzmann Joseph. Présentation. In: Économie rurale. N°144, 1981. pp. 3-4

M. Konopnicki, E. Ben-Rafaël et P. Rambaud, Le Nouveau Kibboutz

Klatzmann Joseph. M. Konopnicki, E. Ben-Rafaël et P. Rambaud, Le Nouveau Kibboutz . In: Annales de Géographie, t. 91, n°506, 1982. pp. 519-521