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R L Berkow

Publications and source records attributed to R L Berkow.

At least 37 records · Page 2Linked to original sources
PubMed1988

Biochemical mechanisms involved in the priming of neutrophils by tumor necrosis factor.

Preincubation of human neutrophils with recombinant tumor necrosis factor alpha has previously been shown by us to enhance superoxide production of neutrophils in response to the chemotactic peptide formyl-methionyl-leucyl-phenylalanine, and the phorbol ester, phorbol myristate acetate. In this study, we further investigate the biochemical basis for this enhancement. We found that in neutrophils, TNF by itself does not induce: (1) an influx of sodium, (2) an alteration in activity or translocation of the calcium and phospholipid dependent protein kinase (C-kinase), or (3) a release of arachidonic acid from preloaded cells. TNF did, however, induce a time- and concentration-dependent increase in the phosphorylation of several neutrophil proteins, with the most dramatic concentration dependent increase in a 64,000 Da protein. Finally, the enhancement of O2 production by pretreatment of neutrophils with TNF was found to be independent of a pertussis toxin-sensitive guanine nucleotide regulatory protein.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1988

Chronic granulomatous disease due to a defect in the cytosolic factor required for nicotinamide adenine dinucleotide phosphate oxidase activation.

The superoxide-generating enzyme of human neutrophils, NADPH oxidase, is present in a dormant state in unstimulated neutrophils. It can be converted to an active form in a cell-free system if both the plasma membrane and cytosol fractions are incubated together in the presence of arachidonic acid. This system was used to determine the nature of the biochemical defect in seven patients with the autosomal recessive, cytochrome b-positive form of chronic granulomatous disease (CGD). A severe deficiency in the cytosol factor was identified in each patient. The defective activity was not caused by the presence of an inhibitor, nor could it be restored to normal by combining cytosol fractions from different patients. In contrast, the membrane fractions from all seven patients contained normal levels of NADPH oxidase when activated in the presence of control cytosol. Of family members tested (obligate heterozygotes for this disorder), seven of eight had intermediate levels of cytosol factor activity. The respiratory burst defect in this form of CGD is caused by an abnormality in the cytosolic factor required for NADPH oxidase activation.

Cytochrome b Group↗
PubMed1988

Cell culture studies and oncogene expression in juvenile chronic myelogenous leukemia.

Juvenile chronic myelogenous leukemia (JCML) may be distinguished from adult CML based upon in vitro cell growth characteristics. We studied four untreated children with JCML and report additional unique findings. Peripheral blood (PB) and bone marrow (BM) cells were grown in soft agar. Without exogenous colony-stimulating activity (CSA) there was exuberant "spontaneous" colony formation in both PB and BM cultures. In the absence of exogenous stimulus, PB colony morphology was predominantly, but not exclusively, monocyte/macrophage. When PB was depleted of adherent cells, "spontaneous" colony formation was nearly completely abrogated. Cultures were also performed in the presence of various sources of CSA including giant cell tumor-conditioned medium (GCT-CM), a melanoma cell line-CM (LD1-CM), human placenta-CM (HPCM), and normal PB mononuclear cell (PBMC) feeder layers. Colony formation was typically increased with HPCM and PBMC, whereas in two patients GCT-CM and LD1-CM failed to stimulate additional colony growth when compared to cultures without exogenous CSA and, in fact, appeared to inhibit baseline "spontaneous" growth. The morphology of colonies in the presence of exogenous stimuli was highly variable. Because of the recent association between the c-fms protooncogene product and the receptor for the monocyte growth factor CSF-1, we analyzed the PB cells from two JCML patients for c-fms expression. Although expressed, c-fms levels were less than that in an adult with Ph1-positive CML in chronic phase. These studies indicate that in JCML, there are dramatic increases in both PB and BM colony-forming cells and that "spontaneous" growth is dependent on an accessory adherent cell fraction. Furthermore, patterns of responsiveness to various sources of CSA suggest that the colony-forming cells may not be a uniform population of malignant cells.

Animals↗
PubMed1987

Enhancement of neutrophil superoxide production by preincubation with recombinant human tumor necrosis factor.

Tumor necrosis factor (TNF) is a 17,000-Da protein which is produced by mononuclear cells upon exposure to endotoxin. Increases in adherence, phagocytosis, hydrogen peroxide release, and lysozyme secretion have been demonstrated after prolonged incubation of human neutrophils with TNF. In this study, the ability of highly purified recombinant human TNF to modulate neutrophil responses to soluble stimuli was evaluated. Tumor necrosis factor alone (0.1 to 10,000 units/ml) failed to induce neutrophil superoxide anion (O2-) production, granule release, or aggregation when incubated for up to 25 min at 37 degrees C. TNF did, however, stimulate a significant time-, dose-, and temperature-dependent increase in neutrophil F-actin content. Although exposure of neutrophils to TNF alone caused no superoxide anion production, it enhanced the O2- production in response to the chemotactic peptide, f-methionyl-leucyl-phenylalanine (FMLP) or the tumor promotor, phorbol myristate acetate, by as much as 278%. The enhancement was time-, dose-, and temperature-dependent and was due to a more rapid initial rate of O2- production. The TNF enhancement of FMLP-induced O2- production was blocked when an anti-TNF monoclonal antibody 241-1H11, is present during the preincubation period. TNF preincubation also enhanced FMLP-induced lysozyme release, but had no effect on aggregation and actin polymerization by FMLP. The kinetics of NADPH oxidase activation by arachidonic acid was unaltered by TNF. These results indicate that brief exposures to recombinant human TNF are able to enhance or prime the neutrophil oxidative burst in response to a second stimulus.

Actins↗
PubMed1987

Specific binding of phorbol esters to nuclei of human promyelocytic leukemia cells.

In this report, we demonstrate that HL-60 nuclei isolated in calcium but not EGTA containing buffers specifically bind PE and express approximately 37,000 receptor sites/nucleus. Nuclear phorbol ester binding is lost by isolation in the absence of calcium, but can be repleted by the addition of partially purified protein kinase C and calcium. When HL-60 cells are treated with bryostatin 1, a compound which activates protein kinase C in a similar fashion to phorbol esters but does not induce differentiation of HL-60 cells, and nuclei are isolated in the presence of EGTA, these nuclei continue to bind phorbol esters. These experiments suggest that HL-60 nuclei bind PE in vitro, and that compounds that activate protein kinase C may increase nuclear binding of PE in situ.

Caenorhabditis elegans Proteins↗
PubMed1987

Functional analysis of the marginating pool of human polymorphonuclear leukocytes.

The intravascular pool of human polymorphonuclear leukocytes (PMN) is composed of one compartment which is circulating and another that is marginated to the vascular endothelium. Administration of B-adrenergic agonists leads to a rapid demargination with an increase in the circulating PMN pool. The marginating PMN has previously been stated to represent an older PMN based on a higher cytochemical alkaline phosphatase activity. With the understanding that circulating PMN are heterogeneous with respect to function and size we undertook the present study to evaluate the contribution of the marginating PMN to functional and volume-dependent heterogeneity. We found that PMN isolated 7 min after epinephrine administration, presumably enriched by marginating PMN, were not different in volume, biochemically measured alkaline phosphatase activity, stimulated superoxide anion release, degranulation, or phagocytosis. These data suggest that the circulating and marginating pools of PMN are interchangeable and that the marginating PMN are not enriched by a particular subpopulation of PMN.

Alkaline Phosphatase↗
PubMed1987

The effect of a protein kinase C inhibitor, H-7, on human neutrophil oxidative burst and degranulation.

The role of C-kinase in the activation of human polymorphonuclear leukocytes has been examined using H-7, a recently described C-kinase inhibitor. We found that H-7 will inhibit PMN superoxide anion release in response to the tumor promotor phorbol myristate acetate and the calcium ionophore A23187. In contrast, no inhibition by H-7 was seen for PMN superoxide release stimulated by the chemotactic peptide FMLP. H-7 did not inhibit PMN NADPH oxidase activity or PMN degranulation by any stimulant, but it reversed a phorbol ester-induced inhibition of granule release by FMLP. The results show that H-7 differentially affects the PMN functional events of secretion and superoxide release and suggests that an H-7 inhibitable C-kinase is not involved in chemotactic peptide induced activation of PMN and may not regulate stimulus induced PMN degranulation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1987

Volume dependent polymorphonuclear leukocytes fractions isolated by counterflow centrifugal elutriation: PMN volume does not correlate with PMN age.

We have previously reported that human peripheral blood polymorphonuclear leukocytes can be separated into at least six volume dependent fractions using counterflow centrifugal elutriation (CCE). Larger volume was shown to correlate with increased superoxide release with either the chemotactic peptide F-met-leu-phe (FMLP) or the tumor promotor phorbol myristate acetate (PMA). To help explain these findings we have examined volume dependent PMN fractions (VDPF) for PMN functions felt to be correlated to PMN age, ie, alkaline phosphatase activity, phagocytosis of opsonized particles, adherence to plastic, and directed movement to FMLP and zymosan activated serum. PMN alkaline phosphatase activity was found to be low in the smallest PMNs, increasing in the PMNs of intermediate size, and then decreasing again in the largest PMN functions. A similar relationship was noted for PMN phagocytic activity. No significant difference among VDPF in adherence to plastic or chemotaxis was found. Furthermore, no difference among VDPF was seen for receptor number or binding affinity of the ligands FMLP or phorbol dibutyrate. Total cellular activity of the NADPH dependent oxidase was, however, 200% greater in the largest compared to the smallest VDPF. Because of the lack of consistent correlation between "age" related PMN function and PMN volume, it is unlikely that PMN volume represents a manifestation of PMN age. It is likely that the increased oxidase activity seen among larger VDPF accounts for the more rapid oxidative burst previously noted.

Adult↗
PubMed1987

Dissociation of human neutrophil activation events by prolonged treatment with amiloride.

Human polymorphonuclear leukocytes (PMNs) can be stimulated to release granule contents and to produce superoxide anion. These functional responses are associated with cellular alkalinization and influx of Na+ in exchange for H+. Amiloride is a potassium-sparing diuretic that will inhibit stimulus-induced Na+-H+ exchange and prevent an increase in cell pH. Amiloride has been shown to inhibit a number of protein kinases including the calcium phospholipid-dependent protein kinase. Because PMA, which binds and activates C-kinase, is a potent stimulus of the PMN, this study was undertaken to investigate the effect of prolonged incubation of PMNs with amiloride on PMN stimulation by the chemotactic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP), the calcium ionophore A23187, opsonized zymosan particles, and the tumor promoter phorbol myristate acetate (PMA). Our results demonstrate that amiloride inhibits superoxide anion production by FMLP, A23187, and opsonized zymosan by causing a slower rate of release and lower maximal release without altering lag time. In contrast, amiloride, despite an inhibition of 22Na+ influx, did not affect superoxide anion production stimulated by PMA. PMN degranulation, phagocytosis, arachidonic acid release, and early influx of calcium were unaffected by preincubation with amiloride. These data suggest that PMN superoxide release induced by FMLP, A23187, and opsonized zymosan is likely modulated by amiloride-sensitive Na+-H+ exchange; and phorbol ester-induced superoxide anion release and degranulation by any stimulant do not appear to be modulated by inhibition of an amiloride-sensitive Na+-H+ exchange.

Amiloride↗
PubMed1987

Tyrosine kinase and phosphotyrosine phosphatase activity in human promyelocytic leukemia cells and human polymorphonuclear leukocytes.

Although an increase in protein phosphorylation on tyrosine was first noted as a result of cell transformation or the application of growth factors to cells, recent reports have shown high levels of tyrosine kinases in nondividing tissues. For that reason, we have investigated whether normal human polymorphonuclear leukocytes (PMN) contain tyrosine kinase and phosphatase activity. Using a copolymer of glutamine: tyrosine as a substrate for the phosphotransferase reaction, we have demonstrated that PMN contain a cytosolic tyrosine kinase activity that elutes as a single peak from Sephacryl S-200 chromatography and has a molecular weight of 70 kilodaltons. Human promyelocytic leukemia cells (HL-60), contain a similar activity (as demonstrated by column chromatography), with only 25% of the activity found in PMN. This cytosolic tyrosine kinase can phosphorylate angiotensin II and a fragment of the src protein containing tyrosine 416, which suggests a similar substrate specificity to other tyrosine-phosphorylating protein kinases. In addition, we have demonstrated that PMN have double the amount of phosphotyrosine phosphatase (PTPase) activity of that found in HL-60 cells. This enzyme has a Km of 0.932 mmol/L and a Vmax of 0.355 mumol inorganic phosphate released/mg protein/min, which is similar to other cellular PTPase. Activation of PMN with f-Met-Leu-Phe and phorbol esters causes a slight but statistically significant drop in PMN PTPase activity. These results suggest that terminally differentiated myeloid cells have high tyrosine kinase and phosphatase activity, which may play a role in stimulus response coupling in the mature PMN.

Cell Line↗
PubMed1986

Bryostatin, an activator of the calcium phospholipid-dependent protein kinase, blocks phorbol ester-induced differentiation of human promyelocytic leukemia cells HL-60.

Phorbol esters bind to and activate a calcium phospholipid-dependent protein kinase (C kinase). Some researchers believe that activation of C kinase is necessary for the induction of phorbol ester biologic effects. Our research indicates that bryostatin, a macrocyclic lactone that binds to the phorbol ester receptor in human polymorphonuclear leukocytes, also binds to this receptor in the human promyelocytic leukemia cell line, HL-60. Bryostatin activates partially purified C kinase from HL-60 cells in vitro, and when applied to HL-60 cells in vivo, it decreases measurable cytoplasmic C kinase activity. Unlike the phorbol esters, bryostatin is unable to induce a macrophage-like differentiation of HL-60 cells; however, bryostatin, in a dose-dependent fashion, blocks phorbol ester-induced differentiation of HL-60 cells and, if applied within 48 hr of phorbol esters, halts further differentiation. These results suggest that activation of the C kinase by some agents is not sufficient for induction of HL-60 cell differentiation and imply that some of the biologic effects of phorbol esters may occur through a more complex mechanism than previously thought.

Binding, Competitive↗
PubMed1986

Purification and functional evaluation of mature neutrophils from human bone marrow.

Human myeloid maturation proceeds within the bone marrow and results in a mature neutrophil that is released into the peripheral circulation. Previous reports have indicated that neutrophils from bone marrow demonstrate decreased adherence, impaired phagocytosis, and decreased nitroblue tetrazolium dye reduction when stimulated. Due to lack of a suitable method for isolating purified bone marrow neutrophils, these studies have been performed by microscopic techniques. We now report a method for isolating 1 X 10(8) neutrophils [bands plus polymorphonuclear leukocytes (PMNs)] from 10 mL of bone marrow aspirate sample. By means of a discontinuous Percoll-gradient centrifugation through densities of 1.085, 1.095, and 1.10 g/mL a leukocyte-rich suspension of bone marrow can be separated into three leukocyte layers. By combining the lower two leukocyte layers (M2/3), a population of neutrophils consisting of 26% bands and 63% PMNs is seen. When compared with peripheral blood PMNs, these bone marrow neutrophils had a lower alkaline phosphatase activity, decreased ingestion of Oil Red O-coated particles, impaired superoxide release on stimulation with the chemotactic peptide Fmet-leu-phe (FMLP) or the tumor promotor phorbol myristate acetate (PMA), and less activity of the NADPH-dependent oxidase. These results indicate that morphologically mature neutrophilic cells within the bone marrow exist in a still functionally immature state.

Alkaline Phosphatase↗
PubMed1985

Bryostatin, a non-phorbol macrocyclic lactone, activates intact human polymorphonuclear leukocytes and binds to the phorbol ester receptor.

Bryostatin, is an antineoplastic agent with activity in both solid and liquid tumors. When added to tissue culture cells this agent shares a number of similarities with phorbol esters. In this report, we evaluate Bryostatin's effect on human polymorphonuclear leukocytes. Bryostatin stimulates the release of specific granules with a parallel dose response curve to phorbol 12-myristate 13-acetate (PMA), but induces release of superoxide at a significantly slower rate than PMA. Competition experiments demonstrate that Bryostatin, although sharing little structural similarity with PMA, can bind to the PMA receptor. In addition, both Bryostatin and PMA stimulate the phosphorylation of almost identical proteins in intact PMNs. These experiments suggest that Bryostatin may activate PMNs by binding to the PMA receptor, which is currently felt to be the calcium, phospholipid-dependent protein kinase.

Binding, Competitive↗
PubMed1985

Volume-dependent human blood polymorphonuclear leukocyte heterogeneity demonstrated with counterflow centrifugal elutriation.

Human peripheral blood polymorphonuclear leukocytes (PMNs) have recently been recognized as a heterogeneous population of cells. Consideration has not been given to the possibility that size may be an additional physical characteristic demonstrating heterogeneity. Using counterflow centrifugal elutriation, we have demonstrated that PMNs can be isolated into at least six volume-dependent fractions. A positive correlation exists for PMN size and superoxide anion release upon stimulation with f-Met-Leu-Phe or phorbol myristate acetate. Total granule contents were also noted to be greater in larger PMN fractions, with a constant percent of release upon stimulation. The implications of these findings are discussed.

Cell Separation↗
PubMed1985

Glycoprotein-180 deficiency: genetics and abnormal neutrophil activation.

Neutrophil function was studied in a patient with polymorphonuclear leukocyte (PMN) glycoprotein-180 deficiency and in her parents. PMNs of the patient had abnormal chemotaxis, phagocytosis, adherence, surface charge, and membrane-associated events of activation. Selective defects to C3b, immunoglobulin G (IgG), phorbol myristate acetate (PMA) and N-formyl-methionyl-leucyl-phenylalanine (FMLP) are described, although C3b receptor density was normal. The parents were found to have abnormal adherence to nylon-wool fibers, abnormal transmembrane potential depolarization with PMA, and reduced amounts of glycoprotein-180 in their PMNs. These studies provide further evidence that the oxidative burst has several different pathways for activation. They demonstrate that the absence of a single PMN surface glycoprotein is associated with a broad spectrum of PMN functional abnormalities. Finally, the observations made in the parents support an autosomal recessive mode of inheritance.

Blood Protein Disorders↗
PubMed1984

Comparative responses of human polymorphonuclear leukocytes obtained by counterflow centrifugal elutriation and Ficoll-Hypaque density centrifugation. II. Membrane potential changes, membrane receptor analysis, membrane fluidity, and analysis of the effects of the preparative techniques.

Standard preparative techniques for human polymorphonuclear leukocytes involves the sequential exposure of the PMN to dextran, Ficoll-Hypaque (FH) gradient centrifugation, and hypotonic stress. Counterflow centrifugal elutriation (CCE) allows isolation of PMN from whole blood without exposure to these potentially toxic substances. We have previously reported that PMN isolated by CCE release more superoxide on stimulation than do PMN isolated by standard techniques (FH PMN). In this report, we extend these observations and show that CCE and FH PMN have similar binding kinetics for the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) and similar membrane fluidity. CCE PMN, however, were noted to have a more marked membrane depolarization on stimulation with FMLP than FH PMN. We show that exposure of purified CCE PMN to dextran increases their superoxide release on stimulation, as well as the available FMLP binding sites. Exposure of FH PMN to elutriation buffer increased their superoxide release on stimulation. It was also noted that both CCE and FH PMN re-exposed to FH increased available binding sites for FMLP. The possible reasons for these findings are discussed.

Adult↗