ABSTRACT
We have investigated the charge ordering (CO) in magnetite below the Verwey transition. A new set of half-integer and mixed-integer superlattice reflections of the low-temperature phase have been studied by x-ray resonant scattering. None of these reflections show features characteristic of CO. We demonstrate the absence of CO along the c axis with the periodicity of either the cubic lattice q=(001) or the doubled cubic lattice q=(001/2). This result suggests that the Verwey transition is caused by strong electron-phonon interaction instead of an electronic ordering on the octahedral Fe atoms.
ABSTRACT
BACKGROUND: Although IFN-beta is 30-40% homologous with IFN-alpha, its intrinsic biological properties are not identical. Compared with IFN-alpha, IFN-beta exerts greater in vitro antiproliferative activity on many cell lines, stimulates peripheral blood stem cells of hairy-cell leukemia (HCL) patients to differentiate to erythroid burst forming cells, has higher specific type I IFN receptor affinity and modulates the expression of class II histocompatibility antigens. IFN-beta would, therefore, be expected to have a greater, or at least similar, antitumor activity as that of the various types of IFN-alpha. METHODS: We have treated 12 patients affected by HCL with IFN-beta and have investigated the biological and immunological changes induced by such treatment. RESULTS: A rise in beta 2-microglobulin and neopterin values throughout IFN-beta therapy was documented in most patients. An increase in NK activity was observed only in clinical responders whose CD57+/CD16+ cell ratio dropped below baseline. There was also a modulation in IFN-gamma synthesis that was dependent on baseline levels and in line with the clinical response. IFN-beta provoked a reduction in CD3+ and CD4+ cell subsets in patients with WBC greater than or equal to 10.0 x 10(9)/1 and greater than or equal to 50% circulating HCs, an expansion in absolute number of CD3+ and CD8+ cell fractions and a slight rise in the absolute values of CD2+ and CD4+ cell subpopulations in patients with WBC less than or equal to 5.0 x 10(9)/1 and less than or equal to 50% circulating HCs. There was no correlation between either the IFN-beta induced increase in beta 2-M or Np levels and clinical response. Most immunological parameters improved or normalized later during the course of IFN-beta treatment, when pathological-hematological signs of disease remission were already evident. CONCLUSIONS: The relevance of the IFN-beta induced changes as well as that of the IFN-alpha induced biological effects in the clinical control of HCL remain unclear.