Cytochemical reaction for cationic proteins as a marker of primary granules during development in chick heterophilis.

The ammoniacal silver reaction (ASR) for cationic proteins was used as a cytochemical marker for the primary or A granules in the cytoplasm of developing heterophils of chick bone marrow. The presence of the electron-dense particulate reaction product of silver, which is localized in the fully formed rod-shaped A granules, provides a marker by which the A granules could be distinguished from the B granules of similar size and by which the formation and maturation of both granule types could be followed through the developmental stages. Progressive developmental stages were ascertained on the basis of decreasing cell size, increasing condensation and margination of the chromatin, and the number and morphology of the granules; the stages were divided into promyelocyte, myelocyte, metamyelocyte and heterophil. During the promyelocyte stage, the first appearance of the electron-dense, membrane-bound, spherical granules (0.3--1.0 micrometer in diameter) is observed in the vicinity of an extensive Golgi complex. They occur in a cytoplasm containing rough-surfaced endoplasmic reticulum, ribosomal clusters, centrioles, mitochondria, microtubules, as well as the membranes, saccules, vesicles and vacuoles of the Golgi complex. These granules are considered as primary but their presence as the only granule type appears very brief. The ASR reaction product is first detected on the surface of these primary granules in late promyelocytes or myelocytes. The secondary or B granule, devoid of reaction for cationic protein at all stages, appears as a condensing vacuole in promyelocytes, but after some A granules are already present. The vacuole contents condense to form the B granules which are 0.1--0.6 micrometer in diameter, often oval-shaped, and contain a loose filamentous material surrounded by a membrane. Tertiary C granules or lysosomes appear during the myelocyte stage as dense core vesicles (0.1--0.2 micrometer in diameter) negative for cationic protein.     

Development ot the granule population in heterophil granulocytes from rat bone marrow

Summary The development of the heterophil granulocyte in the bone marrow of the rat is described, and an electron-microscopical analysis of the changes in the cytoplasm as well as in the granule population in several stages of maturation is reported. Three types of granule originate in consecutive stages of heterophil maturation. Granules with an internal fine structure (nucleated granules) are the first to be formed, i.e., in early promyelocytes; azurophil granules are formed in late promyelocytes; and specific granules appear in myelocytes. Quantitative analysis showed that the granule population in mature cells, i.e., about 160 granules per electron micrograph, is composed of roughly 14% nucleated granules, 10% azurophil granules, and 76% specific granules. Three cell stages were observed in mitosis: the early promyelocyte, the late promyelocyte, and the myelocyte. Granule counts in non-dividing cells confirmed the occurrence of mitosis in the late promyelocyte and myelocyte.     

Investigation of granulocytopoietic kinetics by microdensitometric evaluation of primary granule naphthol-AS-D-chloroacetate esterase activity

Using a scanning microscope photometer we determined quantitatively the enzymecytochemical reaction product for naphthol-AS-D-chloroacetate esterase in neutrophilic granulocytes and their precursors in man. Evaluation of neutrophilic cells from three healthy donors resulted in a logarithm-normal distribution. After subdivision of these cells in their morphologically defined maturational stages no statistically bimodal distribution was shown within the single cell groups. Myelocytes showed twice the amount of the polymorphonuclear neutrophil absorption values. The highest promyelocyte obsorptions were double the values of the myelocyte absorptions. The standard deviation of the absorbance obtained with promyelocytes (which encompass cells already producing granules up to cells reaching their maximal granule content) was significantly higher than the standard deviation of the myelocytes. As already known, primary granules are only synthesized at the promyelocyte stage and - according to the present knowledge - their chloracylesterase and peroxidase activities are not lost during further maturation. Consequently, our results indicate that only enzyme-rich, late promyelocytes undergo mitosis transforming into myelocytes. Correspondingly, their absorption value was halved. Since the absorbance from myelocytes to polymorphonuclears is again halved, myelocytes divide only once. Metamyelocyte absorptions in part correspond to that of myelocytes. This indicates that no distinction can be made between myelocytes with mitotic capacity and "true" if only the size and the nuclear shape are considered metamyelocytes which are not longer capable of undergoing mitosis.     

The influence of histamine on precursors of granulocytic leukocytes in murine bone marrow

The effect of histamine on granulocytic progenitor cells in murine bone marrow was studied in vitro. When bone marrow cells were cultured for three days with the drug, 10(-8) M to 10(-5) M of histamine stimulated differentiation and proliferation of myeloid precursor cells. Subsequently, the number of descendant cells, such as metamyelocytes and neutrophils, increased dose-dependently. Co-existence of equimolar H2 blockers such as cimetidine and ranitidine completely suppressed this effect of histamine, though this was not the case with an H1 blocker/histamine combination. Significant increase in 3H-thymidine incorporation was observed almost exclusively in myeloblasts, promyelocytes and myelocytes after exposure to histamine at concentrations higher than 10(-8) M. Also, selective incorporation of 3H-histamine into bone marrow cells was observed in myeloblasts and promyelocytes, but histamine incorporation was not influenced by the presence of either of histamine agonists or antagonists. While histamine, via H2 receptors, selectively increased the number of granulocytic colony forming units in culture (CFU-C), it had no such effect on macrophage colonies. Considering these findings, it was concluded that histamine promotes proliferation and differentiation of granulocytic myeloid cells via 1) H2 receptors in the CFU-C stage and 2) histamine receptors which are neither H1 nor H2 in the stages of myeloblast and promyelocyte differentiation.     

Identification of normal and leukemic granulocytic cells with merocyanine 540

After fixation in a modified Bouin's solution, the acid dye merocyanine 540 stained granules in granulocytic cells intensely. In immature granulocytes, such as promyelocytes and myelocytes, granules stained pink to violet. In some leukemic myeloblasts, promyelocytes and monocytes, granules also stained deep pink to violet. In more mature granulocytes, such as metamyelocytes, bands, and neutrophils, granules stained bright red to orange. In eosinophils and basophils, granules stained deep red. Granules of the type described were not visualized in normal plasma cells, lymphocytes, monocytes, or megakaryocytes. In normoblasts, cytoplasm stained diffusely red. Cytoplasmic staining in erythroblasts became darker as the cell matured, probably reflecting hemoglobin content. Used as a single agent stain, merocyanine 540 may be useful in distinguishing normal and leukemic granulocytic cells from other types of blood cells.     

Identification of the avian myeloblastosis virus genome. I. Identification of restriction endonuclease fragments associated with acute myeloblastic leukemia.

The proviral DNA of chicken peripheral blood leukemic myeloblasts was analyzed by restriction endonuclease digestion and Southern blotting. Two restriction endonuclease-generated fragments, an EcoRI 2.2-megadalton (Md) and a HindIII 2.6-Md fragment, were present upon enzyme cleavage of all leukemic myeloblast DNA preparations in addition to endogenous or helper-specific fragments. Neither of these fragments was derived from viral DNA of the two known myeloblastosis-associated viruses (MAV-1 and MAV-2). In contrast, DNA similarly treated from the erythrocytes of leukemic chickens showed only small amounts of the two avian myeloblastosis virus-specific fragments, whereas the helper virus-specific fragments were present in the amount seen in MAV-producing chicken embryo fibroblasts. The appearance of the EcoRI 2.2-Md and HindIII 2.6-Md specific fragments in all leukemic myeloblast DNA preparations indicates they are presumably part of the leukemogenic genome that must be present to induce acute myeloblastic leukemia.     

Transmembrane potential responses during HL-60 promyelocyte differentiation

Myeloid cells, including granulocytes and monocyte/macrophages, are important in disease-associated inflammatory reactions. These cells come from a common progenitor, the promyelocyte. The human promyelocytic cell line, HL-60, can be induced to terminally differentiate into granulocytes or monocyte/macrophages in a controlled fashion providing a model to study various aspects of myelomonocytic differentiation. The expression of several ion channels is controlled in HL-60 cells in a differentiation specific pattern. The purpose of this study was to determine if lineage-specific ion channel expression during HL-60 differentiation resulted in differences in functional responses to external stimuli. This was investigated by examining transmembrane potential responses in HL-60 promyelocytes, HL-60-derived polymorphonuclear cells (PMNs), and monocytes to various stimuli using the transmembrane potential sensitive dye, diSBAC₂-(3). Exposure of HL-60 promyelocytes to ionomycin or ATP produced a membrane hyperpolarization. Studies using ion substitutions and ion channel blockers indicate that the hyperpolarization was mediated by K_Ca channels. During HL-60 promyelocyte differentiation to PMNs, the membrane potential response to ionomycin and ATP shifted from a hyperpolarization to a depolarization over 7 days. Conversely, HL-60-derived monocytes exhibited a membrane hyperpolarization in response to ionomycin and ATP. HL-60-derived monocytes also exhibit a Cl⁻ conductance specifically induced by ATP. Lineage-specific expression of ion channels during HL-60 cell differentiation is important in determining the transmembrane potential response of these cells. This may be translated into functional responses of various myelomonocytic cells during disease-associated inflammatory reactions. © 1996 Wiley-Liss, Inc.     

Parameterization of in Vivo Leukemic Cell Populations

A quantitative mathematical formalism which was previously introduced has been utilized to obtain the cell kinetic parameters which characterize the in vivo leukemic myeloblast cell populations in two patients studied by Clarkson and his coworkers. The principal tentative conclusions are: (a) all cells which are actively proliferating must enter the resting state following cell division; (b) about 90% of the cells are in the resting state; (c) the generation time of the cells in the active state is about 25 hr and is essentially the same as the generation time of normal myeloblast cells.     

A lineage-specific Ca(2+)-activated K+ conductance in HL-60 cells.

Cells of the human promyelocytic cell line HL-60 can be controllably induced to terminally differentiate into either granulocytes or monocyte/macrophages. HL-60 promyelocytes and terminally differentiated macrophages express a K(+)-selective ion channel which is activated by intracellular free Ca2+ concentrations above 10(-7) M. Because of its voltage independence, this channel can be distinguished from the voltage- and Ca(2+)-activated family of outward-rectifying channels. The channel is selective for K+ against Na+ and is blocked by Ba2+, thus it may be similar to the Ca(2+)-activated K+ channel previously described in human macrophages. In its sensitivity to block by charybdotoxin, this channel also resembles a Ca(2+)-activated K+ channel of lymphocytes, which plays a role in activation-dependent hyperpolarization. In contrast to promyelocytes and macrophages, functional expression of the Ca(2+)-activated K+ channel is suppressed to nearly undetectable levels in granulocytes derived from HL-60 cells by retinoic acid-induced differentiation. These data suggest that signals which produce elevation of intracellular Ca2+ will hyperpolarize promyelocytes and differentiated macrophages by activating this conductance; however, signals which elevate free Ca2+ in granulocytes must act on other effectors, which may produce a different final influence on membrane potential.     

ImageStream promyelocytic leukemia protein immunolocalization: in search of promyelocytic leukemia cells

Acute promyelocytic leukemia (APL) is a hematological emergency in which a rapid diagnosis is essential for early administration of appropriate therapy, including all-trans retinoic acid before the onset of fatal coagulopathy. Currently, the following methodologies are widely used for rapid initial diagnosis of APL: 1) identification of hypergranular leukemic promyelocytes by using classical morphology; 2) identification of cells with diffuse promyelocytic leukemia (PML) protein distribution by immunofluorescence microscopy; 3) evidence of aberrant promyelocyte surface immunophenotype by conventional flow cytometry (FCM). Here, we show a method for immunofluorescent detection of PML localization using ImageStream FCM. This technique provides objective per-cell quantitative image analysis for statistically large sample sizes, enabling precise and operator-independent PML pattern recognition even in electronic and real dilution experiments up to 10% of APL cellular presence. Therefore, we evidence that this method could be helpful for rapid and objective initial diagnosis and the prompt initiation of APL treatment.     

Identification of Normal and Leukemic Granulocytic Cells with Merocyanine 540

After fixation in a modified Bouin's solution, the acid dye merocyanine 540 stained granules in granulocytic cells intensely. In immature granulocytes, such as promyelocytes and myelocytes, granules stained pink to violet. In some leukemic myeloblasts, promyelocytos and monocytes, granules also stained deep pink to violet. In more mature granulocytes, such as metamyelocytes, bands, and neutrophils, granules stained bright red to orange. In eosinophils and basophils, granules stained deep red. Granules of the type described were not visualized in normal plasma cells, lymphocytes, monocytes, or megakaryocytes. In normoblasts, cytoplasm stained diffusely red. Cytoplasmic staining in crythroblasts became darker as the cell matured, probably reflecting hemoglobin content. Used as a single a p t stain, merocyanine 540 may be useful in distinguishing normal and leukemic granulocytic cells from other types of blood cells.     

On the nucleolar size and density in human early granulocytic progenitors, myeloblasts

Human myeloblasts were studied in bone marrow of patients suffering from chronic phase of chronic myeloid leukaemia to provide more information on the nucleolar diameter in these early granulocytic progenitors. These cells are a convenient model for such study since the number of myeloblasts in diagnostic bone marrow smears of investigated patients is larger than in not-leukemic persons because of the increased granulopoiesis. The nucleolar diameter was measured in myeloblasts after various cytochemical procedures such as methods for visualisation of RNA, DNA and proteins of AgNORs using digitized images and image processing. The results clearly demonstrated that values of the nucleolar diameter depended on the procedures used for visualising nucleoli. It seems to be also clear that a close relationship exists between the diameter of nucleoli and their number since the larger the number of nucleoli per cell the smaller their mean size. However, one of multiple nucleoli present in the nucleus is usually significantly larger. Moreover, the possibility exists that the variability of nucleolar diameter of leukemic myeloblasts and thus the heterogeneity of these cells might depend on various stages of the cell cycle as supported by nucleolar measurements on aging leukemic myeloblasts (K 562 cells) in vitro. Since the staining density of small and large nucleoli did not differ substantially after staining for RNA, it seems to be likely that the nucleolar size is directly related to the total RNA content in myeloblasts. In addition, karyometry combined with RNA cytochemistry still appears to be an useful tool to study nucleoli at the single cell level.     

Vav1 is a crucial molecule in monocytic/macrophagic differentiation of myeloid leukemia-derived cells

Vav1 is a critical signal transducer for both the development and function of normal hematopoietic cells, in which it regulates the acquisition of maturation-related properties, including adhesion, motility, and phagocytosis. Vav1 is also important for the agonist-induced maturation of acute promyelocytic leukemia (APL)-derived promyelocytes, in which it promotes the acquisition of a mature phenotype by playing multiple functions at both cytoplasmic and nuclear levels. We investigated the possible role of Vav1 in the differentiation of leukemic precursors to monocytes/macrophages. Tumoral promyelocytes in which Vav1 was negatively modulated were induced to differentiate into monocytes/macrophages with phorbol-12-myristate-13-acetate (PMA) and monitored for their maturation-related properties. We found that Vav1 was crucial for the phenotypical differentiation of tumoral myeloid precursors to monocytes/macrophages, in terms of CD11b expression, adhesion capability and cell morphology. Confocal analysis revealed that Vav1 may synergize with actin in modulating nuclear morphology of PMA-treated adherent cells. Our data indicate that, in tumoral promyelocytes, Vav1 is a component of lineage-specific transduction machineries that can be recruited by various differentiating agents. Since Vav1 plays a central role in the completion of the differentiation program of leukemic promyelocytes along diverse hematopoietic lineages, it can be considered a common target for developing new therapeutic strategies for the various subtypes of myeloid leukemias.     

Cytochemistry of the acute leukaemias

Summary The use of the Romanowsky staining technique, Sudan Black B, the periodic acid-Schiff reaction and methods for revealing peroxidase, acid and alkaline phosphatases and butyrate, acetate or chloroacetate esterases for identifying and discriminating subvarieties of acute leukaemia at the light microscope level is reviewed and the results of their application in a recent study of the first 720 cases admitted to the Medical Research Council's 8th Acute Myeloid Leukaemia trial summarized. The distribution of varieties of acute myeloid leukaemia and the relevance of age and cytochemical findings to clinical prognosis is presented. Identification of the predominant primitive cell—myeloblast, promyelocyte, monoblast, and others—appears to have little prognostic significance. In fact, the presence of periodic acid-Schiff positive erythroblasts is a bad prognostic sign.The association of certain cytochemical findings with the 15;17 translocation and acute promyelocytic leukaemia, especially the patterns of esterase positivity in Auer rods and the Sudan Black, peroxidase, periodic acid-Schiff and esterase findings characteristic of the 8;21 translocation are illustrated. Cytochemical features helpful in distinguishing acute megakaryoblastic leukaemia, notably the periodic acid-Schiff reaction, differential esterase reactivities and 5-nucleotidase, are discussed and illustrated.Brief reference is made to the cytochemical differentiation of lymphoblastic leukaemias. Details of a technical method for the demonstration of 5-nucleotidase are given.     

Ribonucleotide sequence homology among avian oncornaviruses.

RNA sequence relatedness among avian RNA tumor virus genomes was analyzed by inhibition of DNA-RNA hybrid formation between 3H-labeled 35S viral RNA and an excess of leukemic or normal chicken cell DNA with increasing concentrations of unlabeled 35S viral RNA. The avian viruses tested were Rous associated virus (RAV)-3, avian myeloblastosis virus (AMV), RAV-60, RAV-61, and B-77 sarcoma virus. Hybridization of 3H-labeled 35S AMV RNA with DNA from normal chicken cells was inhibited by unlabeled 35S RAV-0 RNA as effeciently (100%) as by unlabeled AMV RNA. Hybridization between 3H-labeled 35S AMV RNA and DNA from leukemic chicken myeloblasts induced by AMV was suppressed 100 and 68% by unlabeled 35S RNA from AMV and RAV-0, respectively. Hybridization between 3H-labeled RAV-0 and leukemic chicken myeloblast DNA was inhibited 100 and 67% by unlabeled 35S RNA from RAV-0 and AMV, respectively. It appears therefore that the AMV and RAV-0 genomes are 67 to 70% homologous and that AMV hybridizes to RAV-0 like sequences in normal chicken DNA. Hybridization between AMV RNA and leukemic chicken DNA was inhibited 40% by RNA from RAV-60 or RAV-61 and 50% by B-77 RNA. Hybridization between RAV-0 RNA and leukemic chicken DNA was inhibited 80% by RAV-60 or RAV-61 and 70% by B-77 RNA. Hybridization between 3H-labeled 35S RNA from RAV-60 or RAV-61 and leukemic chicken myeloblast DNA was reduced equally by RNA from RAV-60, RAV-61, AMV or RAV-0; this suggests that RNA from RAV-60 and RAV-61 hybridizes with virus-specific sequences in leukemic DNA which are shared by AMV, RAV-0, RAV-60, and RAV-61 RNA'S. Hybridization between 3H-labeled 35S RNA from RAV-61 and normal pheasant DNA was inhibited 100% by homologous viral RNA, 22 TO 26% BY RNA from AMV or RAV-0, and 30 to 33% by RNA from RAV-60 or B-77. Nearly complete inhibition of hybricization between RAV-0 RNA and leukemic chicken DNA by a mixture of AMV and B-77 35S RNAs indicates that the RNA sequences shared by B-77 virus and RAV-0. It appears that different avian RNA tumor virus genomes have from 50 to 80% homology in nucleotide sequences and that the degree of hybridization between normal chicken cell DNA and a given viral RNA can be predicted from the homology that exists between the viral RNA tested and RAV-0 RNA.     

Identification of the avian myeloblastosis virus genome. II. Restriction endonuclease analysis of DNA from lambda proviral recombinants and leukemic myeoblast clones.

Two lambda proviral DNA recombinants were characterized with a number of restriction endonucleases. One recombinant contained a complete presumptive avian myeloblastosis virus (AMV) provirus flanked by cellular sequences on either side, and the second recombinant contained 85% of a myeloblastosis-associated virus type 1 (MAV-1)-like provirus with cellular sequences adjacent to the 5' end of the provirus. Comparing the restriction maps for the proviral DNAs contained in each lambda hybrid showed that the putative AMV and MAV-1-like genomes shared identical enzyme sites for 3.6 megadaltons beginning at the 5' termini of the proviruses with respect to viral RNA. Two enzyme sites near the 3'-end of the MAV-1-like provirus were not present in the putative AMV genome. We also examined a number of leukemic myeloblast clones for proviral content and cell-provirus integration sites. The presumptive AMV provirus was present in all the leukemic myeloblast clones regardless of the endogenous proviral content of the target cells or the AMV pseudotype used for conversion. Multiple cellular sites were suitable for integration of the putative AMV genome and the helper genomes. The proviral genomes were all integrated colinearly with respect to linear viral DNA.     

A simple model of a steady state differentiating cell system

A simple theoretical model is hypothesized to describe the steady state behavior of a differentiating cell system as exemplified by blood cells. The cell system consists of several morphologically distinguishable cell classes which develop sequentially. Each cell class except the last one is mitotically capable. Mitosis is assumed to be either heteromorphogenic, homomorphogenic, or asymmetric. Some algebraic equations are derived which are conservation equations describing the flux of cells from one class to another. The theoretical considerations have been applied to some experimental observations in humans concerning neutrophil production, particularly in reference to relative cell numbers and mitotic fractions of the myeloblast, promyelocyte, and myelocyte cell classes. These observations are utilized to help determine the values of the parameters which characterize the model. Among these parameters are the generation times of the various cell classes, and the predicted values of the generation times are found to be in excellent agreement with observed grain-count halving times. However, the predicted mitotic times are in disagreement with their observed values.