Locomotion of human bone marrow and peripheral blood leukocytes is associated with maturational stage and altered in malignancy.

Using high-resolution phase contrast time-lapse microcinematography, slow movements (0.8-2.0 microns/minute) of human myeloblasts, monoblasts, and megakaryocytes can be recorded. Upon maturation to promyelocytes, motility is lost until cells have reached the stage of metamyelocytes (0.4 microns/minute). Motility increases sharply following maturation into segmented neutrophils (20.4 microns/minute). Monocytes and promonocytes display a mean track velocity of 7.1 microns/minute. The distribution of lymphocyte velocities is not bell-shaped but shows three maxima of 2.1 microns/minute, 7.8 microns/minute, and 18.4 microns/minute. Atypical lymphocytes from patients with infectious mononucleosis belong to the fast group, whereas lymphocytes activated in vitro by mitogens belong to the slow group. Red blood cell precursors from normal human bone marrow do not move actively. In contrast, erythroleukemic blasts show a motility comparable to normal myeloblasts. Similarly, acute promyelocytic leukemia cells move at 6.7 microns/minute, while their normal counterparts are sessile. Increased motility is also observed in blast cells from a variety of acute myelogenous and lymphoblastic leukemias.     

4-Amino-4-deoxy-l-arabinose in LPS of enterobacterial R-mutants and its possible role for their polymyxin reactivity

Abstract The content of 4-amino-4-deoxy- l -arabinopyranose ( l -Arap4N) and the phosphate substitution pattern of the LPS of various strains from Salmonella minnesota, Yersinia enterocolitica and Proteus mirabilis was determined by GC/MS, HPLC and ³¹P-NMR. These data allowed us to examine the possible role of these components for the polymyxin B-binding capacity of LPS and for the minimal inhibiting concentration (MIC) and the minimal bactericidal concentration (MBC) of polymyxins B and E towards the respective R-mutants. Contrary to other investigated Re-, Rd- and Rc-mutants of S. minnesota , strain R595 (Re-mutant) showed about a 90% substitution of the ester-linked phosphate-group with l -Arap4N, whereas the l -Arap4N content of the other S. minnesota strains amounted to 17–25%. Neither the binding capacity of LPS to polymyxin B, determined by a bioassay, nor the MIC- and MBC-values of the R-mutants were significantly affected by this alteration. Similar results were obtained after using the temperature-dependent changes in the l -Ara p4N-content and phosphate substitution pattern of Y. enterocolitica 75R . In order to explore the relevant polymyxin B binding site, lipid A samples with or without substitution of their ester-linked phosphate group were prepared and subjected to the polymyxin-binding assay. The results obtained so far indicated that the inner core bound l -Arap4N, detected in all resistant strains investigated, may play a decisive role in the decreased binding of polymyxin B, responsible for the bacterial resistance towards polymyxin(s).