Synergism between erythropoietin and interleukin-3 in the induction of hematopoietic stem cell proliferation and erythroid burst colony formation

The influence of recombinant erythropoietin (Ep) and interleukin-3 (IL- 3) on the proliferation and differentiation of murine hematopoietic stem and progenitor cells was investigated in serum-deprived cultures. The differentiation of progenitor cells, purified by collecting blast cell colonies from spleen cell cultures of 5-fluorouracil-treated mice, was evaluated by scoring the number and type of colonies appearing after eight days in semisolid culture. IL-3 induced the formation of both erythroid and granulocyte-macrophage colonies in a concentration- dependent fashion, the plateau being reached at 300 U/mL. However, concentrations of IL-3 alone that had little or no effect (less than or equal to 10 U/mL) induced maximal numbers of erythroid bursts in the presence of Ep (1.5 IU/mL). In the presence of Ep alone, no colonies were seen. Proliferation of quiescent hematopoietic stem cells, purified by cell sorting and evaluated by spleen colony assay (CFU-S), was investigated by measuring the total cell number and CFU-S content and the DNA histogram at 20 and 48 hours of liquid culture. Almost no cells or CFU-S survived 20 hours of incubation without the addition of IL-3. The presence of either IL-3 (400 U/mL) or the combination of EP and IL-3 (10 U/mL), supported the maintenance of nearly 40% of sorted CFU-S for 48 hours. Approximately 10% of these cells were in the S phase of the cell cycle at 20 hours and an increase in the total cell number per culture, but not in the CFU-S content, was detected at 48 hours. These data indicate that IL-3 exerts a differentiative and proliferative effect on early stem and progenitor cells, which is concentration dependent. At IL-3 concentrations, which had little or no activity alone, Ep acted synergistically to induce both proliferation of stem cells and differentiation of erythroid progenitors.     

MR imaging of laser-tissue interactions

A new application of magnetic resonance (MR) imaging to map the spatial and temporal distribution of the effects of Nd:YAG lasers on tissues was studied. The temperature dependence of MR relaxation mechanisms and the high sensitivity of MR to changes in the mobility and distribution of tissue water make it particularly suitable for the demonstration and control of thermal energy deposition in tissues. In heterogeneous tissues, MR imaging does not follow changing temperatures directly because even in the case of reversible thermal interactions, there is a hysteresis in the dynamic relationship between MR signal intensity and temperature. Appropriate matching of the laser and MR pulse sequences can, however, optimize the detection of relatively small laser energy deposition, and reversible and irreversible tissue changes can be distinguished. There is a potential for the integration of MR imaging and lasers for three-dimensional control and monitoring of laser-tissue interactions.     

Atheromatous extracranial carotid arteries: CT evaluation correlated with arteriography and pathologic examination

Dynamic, rapid sequence, axial computed tomography (CT) was employed to evaluate the extracranial common and internal carotid arteries in 17 patients with clinical histories suggesting recent or remote ischemia in the territory supplied by the internal carotid artery. The CT findings were correlated with arteriographic observations and with gross and histologic evaluations of endarterectomy specimens. Areas of arterial wall thickening were evaluated on CT scans with regard to both degree of thickening and radiographic density (attenuation). The degree of vessel wall thickening secondary to atheromatous plaque demonstrated on CT scans corresponded closely to the severity of luminal compromise seen on arteriograms. Isodense or mildly hypodense focal mural thickening noted on CT scans of seven endarterectomy specimens proved to be primarily fibrotic (simple) atheromatous plaque on gross and histologic examination. Areas of markedly lucent focal mural thickening on CT scans of 11 specimens all demonstrated varying amounts of subintimal hemorrhage within loosely arranged and rather acellular (complex) atheromatous plaques on pathologic examination. While arteriography provides information regarding the status of the arterial lumen, CT offers the potential of accurate characterization of pathologic changes in the wall of the extracranial carotid arteries in patients with symptoms of cerebral ischemia.     

Mice lacking both macrophage- and granulocyte-macrophage colony- stimulating factor have macrophages and coexistent osteopetrosis and severe lung disease

Mice deficient in granulocyte-macrophage colony-stimulating factor (GM- CSF) and macrophage colony-stimulating factor (M-CSF, CSF-1) were generated by interbreeding GM-CSF-deficient mice generated by gene targeting (genotype GM-/-) with M-CSF-deficient osteopetrotic mice (genotype M-/-, op/op). Mice deficient in both GM-CSF and M-CSF (genotype GM-/-M-/-) are viable and have coexistent features corresponding to mice deficient in either factor alone. Like M-CSF- deficient mice, they have osteopetrosis and are toothless because of failure of incisor eruption. Like GM-CSF-deficient mice, they have a characteristic alveolar-proteinosis-like lung pathology, but it is more severe than that of GM-CSF-deficient mice and is often fatal. In particular, in GM-/-M-/- mice the accumulation of lipo-proteinaceous alveolar material is more marked, and bacterial pneumonic infections are more prevalent and more extensive, particularly involving Gram- negative bacteria. Neutrophilia consistently accompanies pulmonary infections, and some older GM-/-M-/- mice have polycythemia. Survival of GM-/-M-/- mice is significantly reduced compared with mice deficient in either factor alone, and all GM-/-M-/- mice have broncho- or lobar- pneumonia at death. These observations indicate that in vivo, M-CSF is involved in modulating the consequences of GM-CSF deficiency in the lung. Interestingly, GM-/-M-/- mice have circulating monocytes at levels comparable with those in M-CSF-deficient mice and the diseased lungs of all GM-/-M-/- mice contain numerous phagocytically active macrophages, indicating that in addition to GM-CSF and M-CSF, other factors can be used for macrophage production and function in vivo.     

Studies of the role of cellular immunity and angiogenetic changes in the pathogenesis of circumscribed scleroderma

The studies were performed in 48 patients with morphea and included evaluation of 1) antinuclear antibodies 2) lymphocyte induced angiogenesis 3) natural killer (NK) cell activity and 4) T cell subpopulations in peripheral blood. The presence of antinuclear antibodies was found in 44.4% (8/18) patients with scleroderma linearis and in 21% (4/19) patients with morphea disseminata. Lymphocyte induced angiogenesis was increased in 41.5% (17/41) morphea patients, mainly in cases with pronounced vascular changes. The E rosette forming test showed a decreased percentage of active rosette forming cells (ARFC) and total rosette forming cells (TRFC) in peripheral blood and the NK cell activity was lowered in patients with morphea. These results obtained in patients with morphea show some similarities and differences in comparison to cellular immunity disturbances in patients with systemic scleroderma.     

Studies of the mechanism of disorders of the natural killer cell activity in patients with systemic scleroderma

The NK activity of peripheral blood mononuclear cells (PBMC) was evaluated in 90 patients with various subsets of systemic scleroderma (SSc). The NK activity, as performed with K-562 as target cell, was found to be significantly lowered in patients with diffuse scleroderma, but did not differ from the healthy control in patients with acrosclerosis. The lowest values in the NK activity assay were obtained in patients with most extensive skin involvement and severe internal organ changes. The NK activity of healthy donors' PBMC was significantly decreased by addition of SSc patients PBMC (50:1) to the cytotoxicity assay, but was not influenced by the patients sera.