Nonadiabatic spin torque investigated using thermally activated magnetic domain wall dynamics.

Using transmission electron microscopy, we investigate the thermally activated motion of domain walls (DWs) between two positions in Permalloy (Ni80Fe20) nanowires at room temperature. We show that this purely thermal motion is well described by an Arrhenius law, allowing for a description of the DW as a quasiparticle in a one-dimensional potential landscape. By injecting small currents, the potential is modified, allowing for the determination of the nonadiabatic spin torque: ßt=0.010±0.004 for a transverse DW and ßv=0.073±0.026 for a vortex DW. The larger value is attributed to the higher magnetization gradients present.

Blood transfusion and immunomodulation: a possible mechanism.

To induce an immunogenic response in vivo, an antigen-presenting (stimulator) cell must present both antigen-specific (class II MHC) and an accessory signal to the CD4 T cell. Failure to express the accessory signal has been shown in vitro to induce a state of specific unresponsiveness (anergy) in the T cell. We have shown that although stimulator cells in blood continue to express class II MHC molecules during refrigerated storage, their ability to present the accessory signal diminishes, reaching zero in all units tested by about 13 days. This implies that blood in excess of 2 weeks old should not alloimmunize but could induce some degree of immunosuppression. UV-B irradiation and, to a lesser extent, gamma-irradiation, were also shown to inhibit expression of the accessory signal by stimulator cells in blood.

Toxic effects of alkyl-lysophospholipids on human bone marrow and de novo leukaemias. A short overview.

Alkyl-lysophospholipids (ALPs) are reported to have an antineoplastic activity against leukaemic cells. We have tested some halogen-containing ALPs from the Central Institute of Molecular Biology (H. Brachwitz) in comparison with racemic 1-ostadecyl-2-methyl-glycero-3-phosphocholine (ET-18-OCH3) (P.G. Munder, Max-Planck-Institut für Immunobiologie, Freiburg, FRG). We found freshly dissolved ALPs to be very toxic both to human bone marrow and to leukaemic cells of patients. ALP-incubation before cryopreservation is more toxic to bone marrow (but not to AML blasts) than after cryopreservation. All experiments to test the selectivity and to establish a purging protocol should be done using 1, remission marrow including a cryopreservation step and 2, blasts of de novo leukaemias instead of cell as sensitive as HL 60 to ALP-incubation. We found direct toxicity of ALPs to be not suitable for purging lines of bone marrow from patients in remission.

Autologous bone marrow transplantation (ABMT) using unpurged marrow as intensification for first complete remission in acute leukaemia (AL).

In order to assess the clinical advantage of autologous bone marrow transplantation (ABMT) without ex vivo purging, the results in 26 patients (10 AML, 16 ALL) in 1. CR were analyzed retrospectively. All patients received 3 consolidation cycles "in-vivo purging" before marrow harvesting. Beside relapses infections and cardiac failure were the most frequent complications. After 1 to 12.5 months 11 cases relapsed with a higher probability in patients who had a longer period of induction and between CR and ABMT. 12 patients became relapse-free survivors 6 to 53 months after ABMT with a stable plateau after 12.5 months for 8 patients. In conclusion, ABMT following "in-vivo purging" as the strongest one-step postremission therapy in patients with acute leukaemias may be a way for better long-term results in these patients.

[Testing of acute myeloid leukemia of humans using monoclonal antibodies BL-DR, BL-M/G, BL-T2 and BL-Ig-L/1]. / Testung von akuten myeloischen Leukämien des Menschen mittels der monoklonalen Antikörper BL-DR, BL-M/G, BL-T2 und BL-Ig-L/1.

The leukemic blasts of 22 patients with acute myelocytic and myelomonocytic leukemia were tested by indirect immunofluorescence with the monoclonal antibodies BL-DR (directed against HLA-DR-antigens), BL-M/G (react with both granulocytes and monocytes), BL-T2 (pan-T-lymphocyte-antibody CD 5), and BL-Ig-L/1 (anti-light-chains-antibody). The leukemic blasts showed no crossreaction with BL-DR and BL-Ig-L/1. Both the antibodies BL-DR and BL-M/G reacted mainly with the acute myelomonocytic leukemias FAB M4 and only seldom with the acute myelocytic leukemias FAB M1, M2, and M3. The antibodies BL-DR and BL-M/G are able to confirm the diagnosis of acute myelomonocytic leukemia and to classify some previously unclassifiable leukemias.

[The value of cell cultures in leukemias, aplastic anemias and bone marrow transplantations]. / Zur klinischen Wertigkeit von Zellkulturen bei Leukämien, aplastischen Anämien und Knochenmarktransplantationen.

In a survey different methods of culture are represented for the purpose of identifying and quantifying haemopoietic stem cells (CFU-GEMM, CFU-GM, CFU-E/BFU-E) in human bone-marrow or peripheral blood respectively. On the basis of findings from international medical literature their validity is explained in the diagnostics and prognosis of some haematological diseases, such as acute and chronic myeloic leukemia, aplastic anemia, preleukemia. Special attention is given to their significance within bone-marrow transplantation. Their importance in evaluating transplantations after their preceding in-vitro manipulation as to the separation of rest tumour and T-cells is particularly referred to.

[Preservation of Coombs' serum in liquid nitrogen]. / Lagerung von Coombs-Serum in flüssigem Stickstoff.

Experiments with Coombs-sera as raw and usable sera having different levels of titre were carried out in order to examine their stability in fluid nitrogen. Therewith, significant differences concerning the storing stability did not appear. Generally seen two third of the sera retained their initial titres at the end of one year in store.