Tumorigenesis and metastasis of neoplastic Kaposi's sarcoma cell line in immunodeficient mice blocked by a human pregnancy hormone

KAPOSI'S sarcoma (KS) occurs more often in men than in women and HIV-l-associated KS has a high occurrence in homosexual men (over 30%). Most cultures of KS tumours yield cells with properties of hyperplastic (not malignant) endothelial cells under the control of several cytokines 1á€-7. The role of HIV-1 may be in promoting high levels of some cytokines and providing stimulation to angiogenesis by the HIV-1 Tat protein8, which synergizes with basic fibroblast growth factor in promoting these effects9. Here we describe an immortalized AIDS-KS cell line (KS Y-l) and show that these cells produce malignant metastatic tumours in nude mice and are killed in vitro and in vivo (apparently by apoptosis) by a pregnancy hormone, the β-chain of human chorionic gonadotropin. Similarly, chorionic gonadotropin kills KS SLK, cells from another neoplastic cell line (established from a non-HIV-associated KS)10, as well as the hyper plastic KS cells from clinical specimens grown in short-term culture, but does not kill normal endothelial cells. These results provide evidence that KS can evolve into a malignancy and have implications for the hormonal treatment of this tumour. © 1995 Nature Publishing Group.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Migrations et diasporas méditerranéennes (Xe-XVIe siècles)

La Méditerranée a été de tout temps zone de brassage. La période médiévale a vu s'y déployer bien des migrations, proches par leurs caractères des grands déplacements humains de l'époque contemporaine : flux et reflux des marchands italiens allant s'installer dans les comptoirs d'outre-mer, migrations forcées des Arméniens créant un nouveau foyer en Cilicie, ou des juifs espagnols cherchant refuge dans l'empire ottoman après le décret d'expulsion de 1492, migrations économiques d'Albanais, de Coumans, de Syriens, de Bulgares, ou de gens de guerre pour qui ne comptent que l'aventure et l'appât du gain. Les motivations sont multiples, de même que les itinéraires empruntés. Migrations et diasporas, à l'origine de la création de colonies et de comptoirs, révèlent un système de valeurs et montrent comment les groupements humains assurent la continuité et le renouvellement de leurs propres structures, tout en s'adaptant aux changements imposés par la conjoncture. Le monde méditerranéen fut et demeure le lieu de profonds bouleversements humains que seule une différence d'échelle sépare aujourd'hui de ceux d'hier. Saisir ceux-ci dans leur complexité aide à mieux comprendre le monde contemporain

A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log10 increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence