Activation of nervous system development genes in bone marrow derived mesenchymal stem cells following spaceflight exposure.

Stalled cell division in precursor bone cells and reduced osteoblast function are considered responsible for the microgravity-induced bone loss observed during spaceflight. However, underlying molecular mechanisms remain unraveled. Having overcome technological difficulties associated with flying cells in a space mission, we present the first report on the behavior of the potentially osteogenic murine bone marrow stromal cells (BMSC) in a 3D culture system, flown inside the KUBIK aboard space mission ISS 12S (Soyuz TMA-8 + Increment 13) from March 30 to April 8, 2006 (experiment "Stroma-2").

Heterogeneity of clonal development in chronic myeloproliferative disorders.

Recent reports have suggested a previously unexpected variability in the expression of the dominant neoplastic clone in myeloproliferative disorders (MPD). We evaluated 49 female patients with MPD and informative at the X-linked androgen receptor (AR) locus to establish the X chromosome inactivation pattern of hemopoietic cells. Whereas in chronic myelogenous leukemia (CML) the granulocytes (PMN) were uniformly of monoclonal origin, a striking heterogeneity of clonal development was found in PMN from patients with other MPD, with up to 50% of them expressing a polyclonal pattern of X inactivation.

X chromosome inactivation patterns in normal females.

Since one of the two X chromosomes is randomly inactivated at an early stage of female embryonic development, X-linked markers have been used to study the origin and development of various neoplastic disorders in affected heterozygous women; clonality assays have provided a useful tool to the understanding of the mechanisms underlying the development of neoplasia. Recently, a technique of clonal analysis has been devised that takes advantage of a highly polymorphic short tandem repeat within the X-linked human androgen receptor (AR) gene, resulting in a heterozygosity rate approaching 90%. The rapid expansion of the number of women now suitable for X inactivation analysis has however given rise to new controversies, one of the more troublesome being the possibility of a modification of the pattern of X- chromosome inactivation pattern in blood cells of elderly women.