High doses of cytosine arabinoside (HD-Ara-C) as reinforcement during remission of acute myeloid leukemia

High doses of Cytosine-arabinoside (Ara-C) (1 to 3gm/m2 every 12 hours during 48 hours) were administered monthly to 5 acute myeloid leukemia patients during complete remissions subsequent to relapses and reinduction treatment. Plasma Ara-C was measured using a radioimmunoassay and exhibited kinetics compatible with a bi- or tri- compartimental model. Tolerance was good, with mainly gastrointestinal toxicity and somnolence. The duration of remissions was relatively long, taking into account that these were second or third remissions.

The presence within single K-562 cells of erythropoietic and granulopoietic differentiation markers

The continuous cell line K-562, derived from a patient with CML in blast crisis, was examined for markers of granulopoietic (My-1) and erythropoietic (spectrin) differentiation, using specific antibodies detected by indirect immunofluorescence. Both markers were seen, and in 10%--30% of cells, both were present in the same cells. In contrast, the continuous leukemic line HL-60 and KGI contained My-1 only. Controls consisted of colonies in culture containing both granulopoietic and erythropoietic cells (CFU-GEMM). In these, My-1 was seen only in granulopoietic cells and spectrin in erythropoietic cells. The suggestion is advanced that genes coding for differentiation markers are expressed abnormally in K-562.

Granulopoietic differentiation in AML blasts in culture

A newly described monoclonal antibody detected an antigen (My-1) that is expressed on the cell surface during normal granulopoietic differentiation. The kinetics of expression of My-1 and NASD chloracetate esterase were studied during the formation in culture of blast colonies and normal granulopoietic colonies. My-1-positive cells increased during blast colony formation in 6 of 9 experiments, while NASD esterase-positive cells decreased. In contrast, in normal granulopoiesis in culture both markers increased coherently. We suggest that components of granulopoietic differentiation programs are expressed abnormally during blast colony formation in culture.

[Glucocorticoid receptors and leukemia (author's transl)]

Attempts made to establish a correlation between the level of glucocorticoid receptors in leucocytes of leukemic patients and any parameter of steroid sensitivity in vitro have been unsuccessful in most of the cases. These results are in part linked to the marked heterogeneity of the populations studied. In addition, differences of glucocorticoid receptors between circulating leucocytes and bone marrow cells suggest that examination of circulating cells does not accurately reflect the behaviour of the real target cell of glucocorticoid therapy.

Insulin receptors in acute and chronic lymphoid leukaemias

Normal lymphocytes lack insulin receptors. The binding of this hormone was studied in twelve patients with acute lymphoblastic leukaemia (ALL) and fourteen patients with chronic lymphocytic leukaemia (CLL). Lymphoblasts from ALL have been found to possess hormone receptors with properties identical to those of the known target cells for insulin: specificity, pH and temperature dependence, and ligand-induced increase in dissociation rate. All patients with ALL displayed insulin receptors on their lymphoblasts. The null-type cells possessed higher numbers of binding sites than the T-type cells, without overlapping of the values. In the fourteen patients with CLL, eight had low levels of insulin receptors on their lymphocytes while six showed a complete lack of such binding sites. Our results suggest that measurement of insulin binding might be a useful non-immunological marker for the classification of human leukaemias.

Heterogeneity of the in vitro responses to glucocorticoids in acute leukemia

In leukocyte population freshly isolated from the blood of 26 patients with acute leukemia, we have measured several parameters including glucocorticoid receptors, nucleoside incorporation, percentage of cells in S phase, and steroid-induced cell lysis. In addition, in some cases, the short-term response to steroid therapy was determined. Although, in all the patients studied, leukocytes were found to contain glucocorticoid receptors, we failed to demonstrate any correlation between the level of binding sites and the in vitro or in vivo response to glucocorticoids. This absence of correlation could be in part explained by the marked heterogeneity of the steroid response demonstrated in leukocyte subpopulations. It appears, however, that the degree of steroid action in vitro as well as the extent of spontaneous and dexamethasone-induced cell death may be related to the number of cells in the S phase of the cell cycle.

Ultrastructural localization of peroxidases in 'undifferentiated' blasts during the blast crisis of chronic granulocytic leukaemia

Twelve cases of Philadelphia chromosome positive chronic granulocytic leukaemia (CGL) in blast transformation have been investigated using ultrastructural peroxidase detection. In all cases, the leukaemic blasts were negative for myeloperoxidase on the basis of standard cytochemistry. In nine cases a variable proportion of blasts contained peroxidase activity detectable only by electron microscopy, permitting definition of their myeloid nature. By their distinct characteristics and localization, different peroxidase activities were recognized. Thus, several types of blasts were identified: megakaryoblasts (MKB), basophil promyelocytes (BPM), myeloid blasts with small granules containing peroxidase (MyB), and proerythroblasts (ProE). MKB were predominant in two cases and present in four cases, mixed with other myeloid blasts. BPM were abundant in one case and present in seven cases. MyB were identified as a majority in four cases. Three cases remained without any peroxidase. It is concluded that ultrastructural detection of peroxidases is of value for the identification of early myeloid blasts. Their high incidence and the simultaneous presence of several myeloid precursors suggest that during the blast crisis the target cell is frequently a pluripotent myeloid stem cell.

T-lymphocyte colonies in the lymphoproliferative disorders

Human lymphocytes from peripheral blood, bone marrow spleen and lymph nodes were cultured. Continuous phytoheamagglutinin (PHA) stimulation was used, first during a 24 h liquid preincubation, then during a 5 day culture in methylcellulose. In normal donors a rapid colony formation took place, with a mean of 124+/-82 colonies per 1 times 10(5) preincubated lymphocytes. Cells from such colonies were studied by cytology, scanning electron microscopy and rosette formation techniques; arguments favour the hypothesis that these could be T lymphocytes. Neither granulocytes nor macrophages could be grown, and no lymphoid colony formation occurred without PHA stimulation. The same technique was applied to patients with various lymphoproliferative disorders. Significant colony suppression was observed in nearly every case of chronic lymphatic leukaemia; the number of colonies was reduced in some patients with acute lymphatic leukaemia, lymphosarcoma, dysglobulinaemia and Hodgkin's disease. This lymphoid culture method should be applied to a larger number of patients to determine whether it has a classification value and/or prognostic significance. When colonies were grown in pathological states, rosette formation was identical to that of normal donors; colony formation could be due to persisting normal lymphocytes.

[Degree of granularity of the atrial cardiocytes. Morphometric study in rats subjected to different types of water and sodium load (author's transl)]

Morphometric analysis was applied to the evaluation of the atrial cardiocytes specific granules, in rats subjected to different types of water and sodium load. In control animals, the right atrium is more granulated than the left one and the interauricular septum. Ipsilateral atrium and auricle have the same index of granularity. Five types of water and sodium load were tested - I. Full water restriction - II. Sodium restriction with normal water intake - III. Controls - IV. Sodium overloading - V. Sodium and Doca overloading. From groups I to V, the index of granularity decreases progressively. The same phenomenon does not appear in the left atrium, except for the group II (sodium restriction) whose index is higher (p less than 0.001) than in the other groups. These data are not incompatible with the existence of a relationship between the presence of atrial specific granules and the atrial volosensitivity. An analogy between these cells and the myopithelioid cells of the juxtaglomerular apparatus is then suggested.