Magnesium and iron contents of leukemic lymphocytes in acute leukemias and hemolytic anemia

In this study, magnesium and iron concentrations were measured in lymphocytes from patients with acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), and hemolytic anemia (HA) before and after chemotherapy treatment. The results were compared with those of control subjects. Magnesium concentrations were significantly lower in the patient groups, compared with control values. However, no significant differences, except in the HA group, were found among magnesium concentrations of the patient groups them-selves. Iron level values were at physiological range in all groups. Similarly, no statistically significant differences were found between lymphocyte magnesium concentrations before and after chemotherapy treatment in the patient groups. Fe⁺³ values were higher in the ALL and HA groups with respect to the group before chemotherapy.     

A distinct beta-hexosaminidase isoenzyme separated from human leukemic lymphocytes and myelocytes

The beta-hexosaminidase (EC 3.2.1.30) isoenzymes were separated on the basis of their carbohydrate moieties by an affinity chromatography using immobilized phenylboronate. Normal lymphocytes and granulocytes contain two major forms of beta-hexosaminidase, acute lymphoblastic, acute myeloblastic, chronic lymphocytic and chronic myelocytic leukemic cells contain an extra, distinct isoenzyme of beta-hexosaminidase. This extra isoenzyme may be a marker for the leukemic conversion of hematopoietic tissue.     

Deoxycytidylate deaminase activity in non-stimulated and phytohemagglutinin-stimulated human lymphocytes,and in leukemic cells

Deoxycytidylate deaminase isolated from normal human lymphocytes and from mononuclear leucocytes from patients with acute lymphoblastic leukemia, chronic lymphocytic leukemia and acute monocytic leukemia has been characterized in regard to the substrate, dAMP and the allosteric regulators dCTP and dTTP. The enzymes exhibited sigmoidal initial velocity versus dCMP concentration whereas in the presence of the activator, dCTP, Michaelis-Menten kinetics were obtained.At saturating substrate concentrations dTTP acted as an allosteric inhibitor of the enzyme isolated from non-stimulated as well as from stimulated lymphocytes. However, the enzymes isolated from the leukemic cells had lost the allosteric regulation by dTTP.At low substrate concentrations the competitive inhibitor, dAMP, activated all the enzymes. This activation was abolished in the presence of dCTP which indicates that dAMP might be involved in the regulation of dCMP deaminase activity and thus influence the dCTP and dTTP pools under physiological conditions.Abbreviations dCMP deaminase deoxycytidylate deaminase - PHA Phytohemagglutinin - ALL acute lymphoblastic leukemia - CLL chronic lymphocytic leukemia - AMOL acute monocytic leukemia - WBC white blood cells     

Magnesium restriction induces granulocytic differentiation and expression of P27Kip1 in human leukemic HL-60 cells

When cultured in Mg restricted medium, human leukemic HL-60 cells develop morphological and functional granulocytic differentiation. In 0.03 mM Mg, cells display the distinctive features of differentiation, without appreciable inhibition of proliferation. In 0.01 mM Mg, cells show terminal differentiation, accompanied by clear inhibition of proliferation. Such cells accumulate in the G0/G1 phase and subsequently die via apoptosis, similar to HL-60 cells that have been induced to differentiate by DMSO. These phenotypic changes are associated with a marked increase in the expression level of the cyclin dependent kinase inhibitor p27^Kip1. Cyclin E expression is also slightly increased in Mg restricted cells, whereas no changes are observed in the expression level of cyclin D1. We also show that during differentiation cell total Mg decreases, whereas [Mg²⁺]_i increases in both Mg-depleted and DMSO-treated cells. These data suggest that the maturation process is paralleled by a redistribution of intracellular Mg, leading to a shift from the bound to the free form. These changes could modulate the kinetics of Mg-dependent enzyme(s) that are involved in the control of the differentiation pathway. We propose that this model may represent an useful tool for the study of the mechanisms of cell differentiation and related events, such as aging and death. J. Cell. Biochem. 70:313–322, 1998. © 1998 Wiley-Liss, Inc.     

Ganglioside composition of normal and leukemic bovine lymphocytes

The ganglioside composition of bovine peripheral lymphocytes was shown to change sharply under lymphoid leukemia. In normal lymph, lymph nodes, spleen and blood lymphocytes the major ganglioside is N-glycolylhematoside, whereas in calf thymus lymphocytes appreciable amounts of more polar components (GM1- and GD1a-like gangliosides) were found. In leukemic lymphocytes isolated from the same tissues the hematoside content is decreased, while the amount of more polar gangliosides is increased. Possible causes of the altered ganglioside pattern in leukemic lymphocytes are discussed.     

Magnesium homeostasis: Mechanisms and inherited disorders

Mechanisms of magnesium homeostasis intensively studied over the last 10–15 years by means of pathophysiological and molecular genetic approaches have been considered. Impairments of magnesium homeostasis causes the development of magnesium-deficient states, which have been found in many common diseases (diabetes mellitus, cardiovascular diseases, chronic fatigue syndrome, alcoholism, psychiatric and neurologic diseases, etc.), stress condition, effects of some environmental factors as well as therapy with some drugs. Special attention is paid to familial hypomagnesemias caused by genetic defects of magnesium transport systems. The review considers clinical and biochemical characteristics of twelve familial disorders including mechanisms of their development. Deeper understanding of mechanisms of regulation of magnesium homeostasis will results in the development of new approaches in diagnostics, prophylaxis and treatment of magnesium-deficient conditions.     

Antigenic expression of B-cell chronic lymphocytic leukemic lymphocytes

A flow cytometric analysis of lymphocytes in B-cell chronic lymphocytic leukemia (B-CLL) samples and in monocyte-depleted and T-cell-depleted normal peripheral blood (B-PBL) samples was undertaken using 129 reagents from the blind panel (BP) and 72 reagents from the cluster designation (CD) panel obtained from the Fourth International Leucocyte Differentiation Conference and Workshop, B-Cell Section. After determining the average mean channel fluorescence and the average percentage of positive cells for the B-CLL and the normal B-PBL preparations, a combined ratio and difference analysis was performed for each monoclonal antibody reactivity. This analysis confirmed the intense expression of class II antigens on B-CLL and the preferential expression of CD19, CD20, CD23 and CD24 antigens. In addition, three new clustered and three new unclustered antigens were also preferentially expressed on B-CLL lymphocytes. Cluster analysis of these differences suggests the existence of at least three overlapping immunophenotypic subpopulations, composed of CD19, CD20, CD21, CD22, CD23, CD24, CD75, CD76 and CDw78.     

Intramitochondrial rodlet-like inclusions in human leukemic lymphocytes.

Some mitochondria in leukemic cells in two of nine investigated patients with chronic lymphocytic leukemia and in one patient with morphologically less usual form of this disease contained unusual rodlet-like inclusion bodies. These structures were always present in the matrix of frequently dilatated intercristal spaces. The width of rodlet-like inclusions ranged between 10 and 20 nm, their maximal length was 114 nm. All observed rodlet-like inclusion bodies appeared to be composed of fine filaments 2...3 nm in width and resembled the DNA containing structures in mitochondria of few other cell types. In mitochondria of leukemic cells, however, these inclusions represent a further structural abnormality.     

Internalization of low-density-lipoprotein-specific receptors in leukemic guinea pig lymphocytes

Leukemic guinea pig lymphocytes (L2C) have ten times as many low-density lipoprotein (LDL) receptors as healthy lymphocytes, but LDL accounts for only 38% of the cholesterol in L2C cells, compared to more than 95% in normal cells. Our data show that LDL fails to regulate cholesterol biosynthesis and that there is a defect in LDL internalization and receptor turnover in L2C cells. We also demonstrate that the degradation of LDL is not a limiting process. By discriminating between binding and internalization, we show that internalization in L2C is much slower than in normal cells and that the decrease in metabolism is related to the slow turnover of the LDL receptors.     

Observations on prostaglandins in normal and leukemic human lymphocytes

Prostaglandins E (PGE) and F2 alpha (PGF2 alpha) were measured in lymphocytes of normal subjects, children with acute lymphocytic leukemia (ALL), and adults with chronic lymphocytic leukemia (CLL). In ALL lymphocytes PGE increased from a normal value of 25 pgrams to 270 pgrams/10(6) cells, and PGF 2 alpha increased from a normal value of 31 pgrams to 482 pgrams/10(6) cells. In CLL lymphocytes, levels of PGE and PGF2 alpha were normal or low. When normal lymphocytes were stimulated with phytohemagglutinin (PHA), the level of PGE and PGF2 alpha fluctuated, followed by corresponding changes in the level of cyclic nucleotides. In cultured ALL lymphocytes, the level of PGE remained high, while cyclic 3':5'-adenosine monophosphate (c-AMP) level was constantly low, and the initial level of PGF2 alpha fluctuated in relation to similar oscillations of cyclic 3':5'-guanosine monophosphate (c-GMP). These values were lower, although not significantly, when ALL lymphocytes were stimulated with PHA. When CLL lymphocytes were stimulated with PHA, the level of PGE remained low (20 pgrams), as did that of c-AMP. The level of PGF2 alpha, after a brief initial increase (130 pgrams), returned to and remained at a lower level (60 pgrams) while the level of c-GMP was persistently high. These results suggest: (1) prostaglandins may indirectly influence the cell cycle, possibly through modulation of cyclase activity and levels of cyclic nucleotides; and (2) some derangement of this regulatory mechanism may be present in leukemic lymphocytes.     

Magnesium requirement of some of the principal rumen cellulolytic bacteria

Information available on the role of Mg for growth and cellulose degradation by rumen bacteria is both limited and inconsistent. In this study, the Mg requirements for two strains each of the cellulolytic rumen species Fibrobacter succinogenes (A3c and S85), Ruminococcus albus (7 and 8) and Ruminococcus flavefaciens (B34b and C94) were investigated. Maximum growth, rate of growth and lag time were all measured using a complete factorial design, 2(3)×6; factors were: strains (2), within species (3) and Mg concentrations (6). R. flavefaciens was the only species that did not grow when Mg was singly deleted from the media, and both strains exhibited a linear growth response to increasing Mg concentrations (P<0.001). The requirement for R. flavefaciens B34b was estimated as 0.54 mM; whereas the requirement for R. flavefaciens C94 was >0.82 as there was no plateau in growth. Although not an absolute requirement for growth, strains of the two other species of cellulolytic bacteria all responded to increasing Mg concentrations. For F. succinogenes S85, R. albus 7 and R. albus 8, their requirement estimated from maximum growth was 0.56, 0.52 and 0.51, respectively. A requirement for F. succinogenes A3c could not be calculated because there was no solution for contrasts. Whether R. flavefaciens had a Mg requirement for cellulose degradation was determined in NH₃-free cellulose media, using a 2×4 factorial design, 2 strains and 4 treatments. Both strains of R. flavefaciens were found to have an absolute Mg requirement for cellulose degradation. Based on reported concentrations of Mg in the rumen, 1.0 to 10.1 mM, it seems unlikely that an in vivo deficiency of this element would occur.     

Synthesis of nuclear lipids in L2C leukemic lymphocytes

We previously reported that propiconazole strongly inhibits cholesterol synthesis, but not cell division in a stimulated cell, the human lymphocyte cultured with phytohemagglutinin, showing that newly synthesized cholesterol is not necessary for cell division. In this study we labeled the L2C leukemic guinea pig lymphocyte, a naturally stimulated cell, with [2-14C]acetate, and compared the composition of newly synthesized lipids isolated from nuclei and whole cells (or microsomes). We observed that the proportion of cholesterol in labeled non-saponifiable lipids extracted from nuclei was lower than in non-saponifiable lipids isolated from whole cells, whereas the proportion of squalene and polar lipids was higher. By analyzing total lipid extracts, the polar lipids were identified as alkylglycerols, and the above mentioned distribution of constituents was confirmed. The identification of alkylglycerols was also supported by the comparison of radioactive lipid composition after labeling cells with three different lipid precursors: [2-14C]mevalonate, [2-14C]acetate and [2-14C]stearate. When cells were labeled in the presence of dodecylimidazole, the percentage of squalene and alkylglycerols decreased in nuclear lipids, but was not altered when cells were cultured in the presence of propiconazole, a cholesterol synthesis inhibitor which does not affect cell division of human stimulated lymphocytes. We have shown that dodecylimidazole inhibited alkylglycerol biosynthesis and squalene uptake by the nucleus, suggesting that these compounds could play a role in the regulation of cell division.     

Short-term culture of myeloid leukemic cells allows efficient transduction by adenoviral vectors

BACKGROUND: Ex vivo gene therapy of acute myeloid leukemia (AML) requires efficient transduction of leukemic cells. Recombinant adenovirus has been reported to be a poorly efficient vector in leukemic cells. We investigated leukemic cell culture as a possible method of improving the efficacy of this vector. METHODS: Leukemic cell lines and primary cultured AML cells were incubated with adenoviral vectors carrying GFP, LacZ, or IL-12 cDNA. Transduction efficiency was evaluated by measuring adenoviral genome copy number and transgene expression in leukemic cells. The expression of the coxsackie/adenovirus receptor (CAR), CD29, CD49e, and CD51/61 was measured, as was the effect of blocking integrin on adenoviral transduction. RESULTS: Increasing the multiplicity of infection (MOI) to 300 plaque-forming units per cell enhanced transduction of leukemic cell lines and to a lesser degree of AML cells. Analysis of adenoviral genome copy per cell showed only a partial correlation between gene transfer efficiency and transgene expression. Culture of AML cells for 3 days prior to adenoviral transduction increased both adenoviral copy number per cell and the percentage of transgene-expressing cells. CD29, CD49e, and CD51/61 but not CAR expression increased in cultured AML cells between days 0 and 3 and integrin-blocking experiments showed inhibition of transduction in two of four AML samples tested. CONCLUSIONS: Efficient ex vivo gene transfer in primary cultured AML cells can be achieved by short-term culture of leukemic cells prior to gene transfer with adenoviral vectors at a high MOI. This effect appears to be at least partially mediated by enhanced integrin expression.     

Magnesium profile in autism

The aim of the present study was to determine and compare plasma and erythrocyte concentrations of magnesium in 12 autistic children (10 boys, 2 girls), 17 children with other autistic spectrum disorders (14 boys, 3 girls), 5 girls with classic Rett syndrome, and 14 normal children (7 boys, 7 girls) of the same age. No differences in intracellular Mg were found between controls and pathological subjects; however, autistic children and children with other autistic spectrum disorders had significantly lower plasma concentrations of Mg than normal subjects (p=0.013 and p=0.02, respectively). Although our study population was small, we conclude that children with autistic spectrum disorders require special dietary management. If these cases are diagnosed at an early stage, they can be helped through diet.     

Observations on prostaglandins in normal and leukemic human lymphocytes

Prostaglandins E (PGE) and F₂ (PGF₂) were measured in lymphocytes of normal subjects, children with acute lymphocytic leukemia (ALL), and adults with chronic lymphocytic leukemia (CLL). In ALL lymphocytes PGE increased from a normal value of 25 pgrams to 270 pgrams/10⁶ cells, and PGF₂ increased from a normal value of 31 pgrams to 482 pgrams/10⁶ cells. In CLL lymphocytes, levels of PGE and PGF₂ were normal or low. When normal lymphocytes were stimulated with phytohemagglutinin (PHA), the level of PGE and PGF₂ fluctuated, followed by corresponding changes in the level of cyclic nucleotides. In cultured ALL lymphocytes, the level of PGE remained high, while cyclic 3′:5′-adenosine monophosphate (c-AMP) level was constantly low, and the initial high level of PGF₂ fluctuated in relation to similar oscillations of cyclic 3′:5′-guanosine monophosphate (c-GMP). These values were lower, although not significantly, when ALL lymphocytes were stimulated with PHA. When CLL lymphocytes were stimulated with PHA, the level of PGE remained low (20 pgrams), as did that of c-AMP. The level of PGF₂, after a brief initial increase (130 pgrams), returned to and remained at a lower level (60 pgrams) while the level of c-GMP was persistently high. These results suggest: (1) prostaglandins may indirectly influence the cell cycle, possibly through modulation of cyclase activity and levels of cyclic nucleotides; and (2) some derangement of this regulatory mechanism may be present in leukemic lymphocytes.     

Performance Improvement of Magnesium Sulfur Batteries with Modified Non‐Nucleophilic Electrolytes

The combination of a magnesium anode with a sulfur cathode is one of the most promising electrochemical couples because of its advantages of good safety, low cost, and a high theoretical energy density. However, magnesium sulfur batteries are still in a very early stage of research and development, and the discovery of suitable electrolytes is the key challenge for further improvement. Here, a new preparation method for non‐nucleophilic electrolyte solutions using a two‐step reaction in one‐pot is presented, which provides a feasible way to optimize the physiochemical properties of the electrolyte for the application in magnesium sulfur batteries. The first use of modified electrolytes in glymes and binary solvents of glyme and ionic liquid shows beneficial effects on the performance of magnesium sulfur batteries. New insights into the reaction mechanism of electrochemical conversion between magnesium and sulfur are also investigated.     

LDL-mediated targeting of liposomes to leukemic lymphocytes in vitro.

We describe a method for the covalent coupling of low-density lipoproteins (LDL) to the surface of small unilamellar vesicles, and the delivery of the liposome content to leukemic L2C lymphocytes in vitro. We demonstrate the stability of the linkage between LDL and liposomes, the preservation of vesicle integrity and the affinity of the LDL for their specific receptors after the coupling reaction. Hygromycin B, an impermeant inhibitor of protein synthesis, was encapsulated in the targeted liposomes, and delivered into the cytoplasm of leukemic L2C lymphocytes by the LDL pathway, as demonstrated by the lethal effect on cells measured by 51chromium-release assay.