The myelodysplastic syndromes (MDS) are disorders in which the abnormalities are thought to be confined to cells of the myeloid series. However, examination of peripheral blood from 56 patients with MDS showed that the majority had low lymphocyte counts. In a detailed study of 2 5 patients, using OKT3, OKT4 and OKT8 monoclonal antisera together with SRBC rosettes, it was shown that there is a consistent and significant reduction in peripheral blood T lymphocytes. This decrease was primarily confined to the OKT4-defined helper subpopulation. There is a consequent relative increase in the OKT8-defined subset but in absolute numbers however, suppressor cells are reduced compared to normal particularly in those patients with lymphopenia. No correlations between T cell abnormalities and the different morphological groups of MDS were found. The possible implications of the reversed helper/suppressor ratio in the pathogenesis of MDS are discussed.
Absolute T cell counts and the relative distributions of antibody-defined helper and cytotoxic/ suppressor T lymphocytes are reported in 26 patients with chronic idiopathic thrombocytopenic purpura (ITP). T cell numbers are generally normal in ITP and alterations in relative helper (OKT4 positive) and suppressor (OKT8 positive) T cell numbers show no consistent patterns, although 35 % of the cases examined showed inverted distributions. The combined percentages of helper and suppressor T cells consistently exceeded 100 % in ITP indicating the presence of increased OKT4+8+ cells in these patients. A cell population, previously defined as SRBC positive and OKT3 negative, was found in the normal group and in ITP patients following splenectomy but was absent in those patients with intact spleens.The role of these changes in the pathogenesis of ITP is discussed.
The myelodysplastic syndromes (MDS) are disorders in which the abnormalities are thought to be confined to cells of the myeloid series. However, examination of peripheral blood from 56 patients with MDS showed that the majority had low lymphocyte counts. In a detailed study of 25 patients, using OKT3, OKT4 and OKT8 monoclonal antisera together with SRBC rosettes, it was shown that there is a consistent and significant reduction in peripheral blood T lymphocytes. This decrease was primarily confined to the OKT4-defined helper subpopulation. There is a consequent relative increase in the OKT8-defined subset but in absolute numbers however, suppressor cells are reduced compared to normal particularly in those patients with lymphopenia. No correlations between T cell abnormalities and the different morphological groups of MDS were found. The possible implications of the reversed helper/suppressor ratio in the pathogenesis of MDS are discussed.
A description of the anisotropy of elastic and nonlinear acoustic properties of dense (95% of theoretical), highly textured, sinter-forged, ceramic Bi~Sr2CaCu208+~(Bi-2:2:1:2)high-T, superconductors is provided from measurements of the velocities of longitudinal and shear ultrasonic waves as functions of temperature and hydrostatic pressure. A high proportion of the grains are aligned preferentially with the c axis along the forging direction in this material, while it is essentially isotropic in the plane normal to the forging axis. A complete set of the elastic stiffness tensor components has been determined as a function of temperature from 10 to 290 K, treating this material as if it had cylindrical symmetry. The results are used to compute the orientation dependences of the Young's modulus and Poisson's ratio which are compared with those estimated for single crystal Bi-2:2:1:2.The main finding is a marked anisotropy of the elastic stiffness moduli and their dependences on pressure. The elastic and nonlinear acoustic properties of the textured and single-crystal Bi-2:2:1:2comply with the behavior expected for a layerlike material with rather weak interlayer binding forces: C» ) C33 the linear compressibility and thermal expansion along to the c axis, i.e. , normal to the layers, being substantially larger than in the ab plane. The hydrostatic pressure derivative (BC33/BP)p -p(=21.3) of the elastic stiffness tensor component, which corresponds to a longitudinal wave propagated along the c axis, is larger than that (BC»/BP)p=o(=15. 1), for such a wave propagated in the ab plane. The anisotropies of the linear compression and the acoustic mode Griineisen parameters are also typical of a layerlike material.
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