bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of Fatty Acid Metabolites in the Differentiation of the Human Monocyte-Like Cell Line U937
Authors: Bomalaski John S , Freundlich Bruce , Steiner Sheldon , Clark Mike A 
Published: January 2018

Abstract
The human monocyte cell line, U937, can be induced to terminally differentiate into macrophage-like cells when treated with gamma-interferon. However, if these cells were treated with gamma-interferon and esculetin, an inhibitor of the lipoxygenase pathway, or BW755C, an inhibitor of both the lipoxygenase and the cyclooxygenase pathways, a marked inhibition in cellular differentiation occurred. In contrast, inhibitors of only the cyclooxygenase pathway had no effect on differentiation. These studies suggest a role for lipoxygenase products of arachidonic acid in the differentiation of the human U937 cell line. Arachidonic acid utilized in the production of eicosanoids is derived from phospholipids by the action of phospholipase A2 and phospholipase C. When U937 cells were cultured in medium supplemented with gamma-interferon, there was a striking increase in the level of phosphatidylcholine and phosphatidylethanolamine-specific phospholipase A2 activities and phosphatidylinositol-specific phospholipase C activity as compared to control cells. Morever, although there was not a significant difference in the incorporation of labeled arachidonic acid or linoleic acid into the major phospholipids of differentiated U937 cells as compared to undifferentiated control cells, there was a marked increase in the relative amount of the labeled arachidonic acid released from the differentiated cells as lipoxygenase products compared to cyclooxygenase products. These data suggest that lipoxygenase products may be essential in the differentiation process of U937 cells and that enhanced phospholipase enzyme activities that occur during differentiation help explain how arachidonic acid becomes available to form lipoxygenase products.
Biochemical and Pharmacologic Characterization of a Phosphatidylinositol-Specific Phospholipase C in Rat Neutrophils
Authors: Mackin William M , Stevens Theresa M 
Published: January 2018

Abstract
The phosphatidylinositol (PI)-specific phospholipase C (PLC) activity contained in sonicates of casein-elicited (4-6 hr) rat neutrophils has been identified and characterized. With phosphatidylinositol (PI) as the substrate, PLC activity is found both in the supernate and pellet of a 100,000g spin of the neutrophil sonicate. Further fractionation of the crude sonicate by centrifugation on discontinuous sucrose gradients indicates that the PLC activity is predominantly cytosolic with lesser amounts of activity found in the plasma membrane and granule enriched fractions. Hydrolysis of PI by the sonicate PLC is linear for 15-20 min at 37° and also with respect to the amount of sonicate protein added. The enzyme shows selectivity for PI with little, if any, hydrolytic activity towards other phospholipids such as phosphatidylethanolamine (PE), phosphatidylserine (PS), or phosphatidylcholine (PC). The PLC activity has a pH optimum of 5.5-6.0, is enhanced 1.5-3-fold by the addition of deoxycholate, and is Ca+ + dependent. Kinetic analysis of the PLC hydrolysis of PI yields an apparent Km of 240 ± 85 μM and a Vmax of 34.3 ± 17.0 nmol/min/mg protein (n = 3). Similarly, when phosphatidylinositol 4,5 bisphosphate (PIP2) is used as substrate, an apparent Km of 109 ± 66 μM and a Vmax of 14.3 ± 10.4 nmol/min/mg (n = 3) protein is obtained. These data suggest that PIP2 may be a slightly better substrate for the PMN PLC relative to PI. Finally, a variety of drugs previously reported to inhibit platelet PLC activity in vitro were tested for their ability to inhibit rat PMN PLC. Of the compounds tested, none were potent (i.e., IC50 values 100 μM) inhibitors of the PMN PLC.
Functional and Biochemical Properties of Rat Kupffer Cells and Peritoneal Macrophages
Authors: Laskin Debra L , Sirak Andrea A , Pilaro Anne M , Laskin Jeffrey D 
Published: January 2018

Abstract
Functional and biochemical techniques were used to further characterize heterogeneity between rat Kupffer cells and peritoneal macrophages. Both macrophage cell types were found to phagocytize antibody coated sheep red blood cells in a time-dependent manner. However, Kupffer cells were two to three times more phagocytic than were peritoneal macrophages. In contrast, the peritoneal cells released significantly more superoxide anion in response to the complement cleavage product, C5a and the phorbol ester tumor promoter, 12-0-tetradecanoyl-phorbol-13-acetate, and produced more hydrogen peroxide than did the liver macrophages. Both cell types responded chemotactically to C5a. These results suggest that macrophages may develop specialized functions depending on the needs of their local environment. Using one and two dimensional SDS-polyacrylamide gel electrophoresis, we also compared the production of newly synthesized proteins by Kupffer cells and peritoneal macrophages. In general, the macrophages were found to produce similar types and numbers of proteins with some exceptions. These included proteins that were unique to peritoneal macrophages and other proteins observed only in Kupffer cells. The production of these proteins in liver macrophages did not appear to correlate with levels of functional activation, but may be more related to the tissue origin of the cells.
Induction of Continuous I-A Expression by Murine Peritoneal Macrophages: Lack of Correlation With T Cell Responses of Bcgr and Bcgs Mice
Authors: Kwasniewski Michael N , Zwilling Bruce S 
Published: January 2018

Abstract
The induction of continuous I-A expression by L3T4 and Lyt2 lymphocyte subpopulations from Bcgr and Bcgs mice was compared. We found that the induction of continuous I-A expression was independent of the Bcg geneotype of the T cells. T cells from congenie Begs BALB/c mice and C.D2Bcgr mice could not induce continuous I-A expression in vitro and were deficient in their ability to produce IFN-gamma in vitro. In contrast, T cells from other strains of Bcgr and Bcgs mice could induce continuous I-A expression. Both recombinant IL-2 and IL-4 acted synergistically with low levels of IFN-gamma to induce continuous I-A expression by macrophages from Bcgr mice.
Maintenance of Peritoneal Macrophages in the Steady State
Authors: Melnicoff Meryle J , Horan Paul K , Breslin Elizabeth W , Morahan Page S 
Published: January 2018

Abstract
Resident peritoneal macrophages (Mø) were labeled in situ by intraperitoneal (i.p.) injection of the green fluorescent cell tracking dye PKH-1. After immunofluorescence staining with Mø specific monoclonal antibodies (Mabs) and phycoerythrin (PE) second antibody, the resident Mø were labeled with both the green dye and red Mab label, while recruited Mø were labeled only with the red Mab tag. These populations were distinguished by two-color flow cytometry.
PKH-1 labeled resident peritoneal Mø were followed for 1-49 days in mice that received no further treatment (steady state). Dye labeled Mø were still detectable after 49 days in vivo, although their green fluorescence intensity had decreased steadily over time. The decrease in dye intensity was limited to Mø, as the fluorescence intensity of PKH-1 labeled peritoneal lymphocytes did not change.
Resident Mø populations were clearly separated from recruited Mø by the intensity of their staining with PKH-1 for up to 28 days. No decrease in the number of resident (dye labeled) peritoneal Mø was observed over 1-28 days. These data indicate that resident peritoneal Mø were not replaced by recruited blood monocytes in the steady state.
Photoreversal of the Ultraviolet Radiation-Induced Disappearance of ATPase-Positive Langerhans Cells in the Epidermis of Monodelphis domestica
Authors: LeVee G J , Applegate L A , Ley R D 
Published: January 2018

Abstract
The present study was undertaken to explore the possible causes of ultraviolet radiation (UVR)-induced disappearance of ATPase-positive, epidermal Langerhans cells (LC). Monodelphis domestica was used because it has the capacity for photoreactivation of UVR-induced pyrimidine dimers in epidermal DNA. Single, 330 J/m2 (ears) or 500 J/m2 (back) UVR exposures (FS-40 sunlamps) reduced the numbers of ATPase-positive epidermal LC in M. domestica ears to ~15% of those in unirradiated ears and ~37% of those in unirradiated dorsal skin. Immediate 90-minute exposures to photoreactivating light (PRL, 320–400 nm) post-UVR reversed the effects of the UVR, resulting in ATPase-positive LC numbers not being significantly different from controls. Exposure to PRL immediately proceeding UVR did not prevent ATPase-positive LC disappearance. The photoreactivation of UVR-induced ATPase-positive LC disappearance indicates that DNA damage (pyrimidine dimers) is involved in the loss of ATPase-positive LC.
Staphylococcus aureus Tetrapeptide With High Chemotactic Potency and Efficacy for Human Leukocytes
Authors: Rot Antal , Henderson Louis E , Sowder Raymond , Leonard Edward J 
Published: January 2018

Abstract
A chemotactic tetrapeptide from culture fluids of Staphylococcus aureus was purified to homogeneity by reverse-phase high-pressure liquid chromatography. The peptide comprises equimolar methionine, leucine, isoleucine, and phenylalanine. It inhibited binding of fluoresceinated fMet-Leu-Phe-Lys to human monocytes, which showed that it interacted with the formyl-methionyl peptide receptor and suggested that it was a formyl-methionyl peptide. Based on a comparison of dose-response curves for inhibition of fluoresceinated fMet-Leu-Phe-Lys binding, the relative affinity of the peptide for the receptor was comparable to that of fMet-Leu-Phe-Lys. At optimal concentrations, chemotactic efficacy (percentage of monocytes migrating to the attractant) was 53 ± 4%, in contrast to 36 ± 3% for the reference attractant fMet-Leu-Phe. Since approximately 60% of human monocytes have formyl-peptide receptors, the bacterial peptide is capable of attracting all receptor-bearing monocytes.
Macrophage Subset Repopulation in the Spleen: Differential Kinetics After Liposome-Mediated Elimination
Authors: van Rooijen Nico , Kors Nel , Kraal Georg 
Published: January 2018

Abstract
Different macrophage subsets can be discriminated in the well defined compartments of the mouse spleen by specialized functions and the presence of specific surface determinants. Red pulp macrophages, marginal zone macrophages, and marginal metallophilic macrophages are eliminated simultaneously within 24 hr by a single injection with liposome-entrapped dichloromethylene diphosphonate (DMDP). After such elimination, these subsets show a striking difference in their kinetics of reappearance: Red pulp macrophages are back in normal numbers after 1 week, the marginal metallophilic macrophages take 2 weeks to regain fully their position at the border of the marginal zone and periarteriolar lymphocyte sheath, but it takes over 1 month for complete reappearance of the marginal zone macrophages. Marginal zone lymphocytes, also affected by treatment with the liposome-entrapped drug, reappeared in the marginal zone within 2 weeks, indicating that marginal zone macrophages are not required for their localization and/or retention there. Approximately 2 weeks after treatment, all cells in the spleen have returned to normal numbers with the exception of marginal zone macrophages, which can be found only sporadically at that time. The results indicate that these macrophage subpopulations must have different precursor requirements. The differential reappearance of the macrophages creates the possibility of studying lineage analysis and will help to unravel the precise function of the marginal zone macrophages and marginal metallophilic macrophages in particular.
Confocal Scanning Fluorescence Microscopy: A New Method for Phagocytosis Research
Authors: Hook Gregory R , Odeyale Charles O 
Published: January 2018

Abstract
An important new method for phagocytosis research, confocal scanning fluorescence light microscopy (CSFM), is demonstrated using fluorescent microspheres ingested by murine macrophages. CSFM, in combination with Nomarski differential interference contrast microscopy (DIC). can resolve microspheres inside cells from microspheres attached to the surface of cells. Further, combined CSFM and DIC images can quantitate phagocytosis by individual cells aggregated together. No other method offers these capabilities. A comparison of CSFM and conventional epifluorescence light microscopy (EFM) images shows that CSFM produces significantly higher-resolution images of microspheres than EFM, primarily because CSFM excludes the out-of-focus light artifacts of EFM.
Macrophage Activation for Cytolysis of Virally Infected Target Cells
Authors: LeBlanc Paul A 
Published: January 2018

Abstract
Bone-marrow-culture-derived macrophages killed virally infected cells but not uninfected cells. This activity could be enhanced by preexposure of the macrophages to lipopolysaccharide (LPS), and/or purified interferons. The ability to kill virally infected targets was not restricted to a single cell type or virus. Comparing the ability of activators to induce activity against virally infected targets or tumor (P815) targets, it was found that much lower levels of LPS or α/β-interferon were able to induce cytolytic activity for virally infected cells than were needed for tumor targets. Further, while the antitumor activity did not change significantly with an increase in the time of exposure to activating stimuli from 4 to 24 h, the activity against virally infected cells decreased dramatically with the longer exposure to stimuli.
Receptor-Mediated Endocytosis of Carcinoembryonic Antigen by Rat Alveolar Macrophages In Vitro
Authors: Toth Carol Ann , Rapoza Alan , Zamcheck Norman , Steele Glenn , Thomas Peter 
Published: January 2018

Abstract
Uptake of carcinoembryonic antigen (CEA) by isolated rat alveolar cells was time, temperature, and concentration dependent (Kuptake, = 2.4 × 10-7M). Pretreatment of the alveolar cells with colchicine inhibited internalization of CEA. Uptake of 125Mabeled CEA by alveolar cells required divalent cations and was inhibited by cold CEA and nonspecific cross-reacting antigen (NCA). The carbohydrate portion of CEA was modified by neuraminidase treatment and Smith degradation. The modified glycoproteins inhibited endocytosis by the alveolar macrophages, thus excluding nonreducing terminal carbohydrate residues as the recognition site of the receptor. Endocytosis of CEA was independent of native protein conformation since performlc acid oxidized CEA and glycopeptides produced by pepsin digestion were inhibitory. Rat alveolar macrophages bound CEA with similar specificity to that of rat Kupffer cells. Alveolar macrophages, unlike Kupffer cells, did not rapidly exocytose the internalized CEA. Neither P388D1, a macrophage-like murine cell line, nor murine peritoneal exudate cells were capable of endocytosing CEA in vitro.
Induction of Proteins in Interferon-α- and Interferon-γ-Treated Polymorphonuclear Leukocytes
Authors: Rubin Berish Y , Anderson Sylvia L , Lunn Ruth M , Smith Larry J 
Published: January 2018

Abstract
Interferon-γ (IFN-γ) treatment of polymorphonuclear leukocytes (PMNs) results in an activation of their functions. Studying the IFN responsiveness of PMNs and using antibodies to the IFN-induced proteins, we have observed the ability of IFN-α to stimulate the production of the IFN-induced 67,000 and 56,000 dalton proteins and the ability of IFN-γ to induce the synthesis of the 67,000, 56,000, and 42,000 dalton proteins. The induction of these proteins is dependent on de novo RNA synthesis, as its induction is inhibited if the IFNs and actinomycin D are added to the cells simultaneously. The results of this study confirm the ability of PMNs to carry out gene activation and demonstrate the ability of PMNs to respond to both IFN-α and IFN-γ.
Transglutaminase Levels and Immunologic Functions of BCG-Elicited Mouse Peritoneal Macrophages Isolated by Centrifugal Elutriation
Authors: Khera Vimlarani , Mehta Kapil 
Published: January 2018

Abstract
BCG-elicited mouse peritoneal macrophages were separated into three subpopulations by counterflow centrifugal elutriation. The three subpopulations were characterized on the basis of the level of a protein cross-linking enzyme, tissue transglutaminase. Subpopulation-3 consisted of large cells (&gt;95% esterase positive and &gt;90% viable) and had at least a fivefold higher transglutaminase activity (35 ± 6 nmol/hr/mg) as compared to macrophages in subpopulation-1 (6 ± 2 nmol/hr/mg) and at least a threefold higher enzyme activity as compared to subpopulation-2 (11 ± 2 nmol/hr/mg). Subpopulation-3 also showed sevenfold higher phagocytosis of IgG-coated sheep red blood cells. The three subpopulations showed no difference in their ability to kill Listeria monocytogenes as determined by [3H]-thymidine release. Subpopulations-2 and -3 caused 90% inhibition of murine adenocarcinoma (EMT-6) tumor cell growth in the presence or absence of lipopolysaccharide. Subpopulation-1 had a poor ability to inhibit EMT-6 cell growth (29 ± 12%). However, in the presence of lipopolysaccharide, this activity increased by at least threefold (92 ± 7%). The three subpopulations showed no significant difference in their cytolytic activity against murine mastocytoma (P815) target cells in the presence or absence of lipopolysaccharide. These results suggest that tissue transglutaminase may have no significant role in bactericidal, tumoricidal, or tumoristatic function of macrophages; however, it might have some role in promoting the Fc-receptor-mediated phagocytic function of the macrophages.
Differential Induction of Macrophage GSIB4-Binding Activity
Authors: Tabor Dale R , Larry Cynthia H , Jacobs Richard F 
Published: January 2018

Abstract
Activated macrophages display a terminal galactopyranosyl group on their membrane surface that binds the lectin Griffonia simplicifolia–IB4 (GSIB4). Using FITC-conjugated GSIB4, we examined the induction and subsequent expression of this corresponding marker on peritoneal macrophages from normal (NMO) and LPS-treated (LPS MO) mice. Although the percentage of fresh LPS MO explants that bound GSIB4 was always higher when compared to the NMO counterparts, marker expression on the latter was readily enhanced by cufturing the cells in vitro either alone or with stimuli. Moreover, we found that an increase in this activity was promoted by either nonspecific phagocytosis of latex beads, or γ-interferon (γ-IFN) treatment. Further investigation showed that a prerequisite sequence of signal delivery to the macrophages was associated with maximal expression of the GSIB4 binding. When γ-IFN treatment preceded latex bead ingestion, maximum GSIB4 binding occurred. Data obtained from using short-term (1 hr) and long-term (24 hr) exposure to latex beads showed that metabolic processing of induction signals was required to enhance the response over time. This yielded better GSIB4-binding activity when responses to these pulses were analyzed in freshly explanted macrophages.
The overall results of this study demonstrated that macrophage binding of GSIB4 was differentially associated with stimuli induction. Moreover, select signals in the form of soluble mediators, or the mechanical events characteristic of internalization were capable of eliciting an increase in the percentage of macrophages that were positive for binding GSIB4. Thus, the enhanced affinity for binding this lectin may serve as a useful marker to determine the magnitude of macrophage responsiveness when these cells are examined following their exposure to different stimuli.
Differential Release of Mediators From Human Basophils: Differences in Arachidonic Acid Metabolism Following Activation by Unrelated Stimuli
Authors: Warner Jane A , Peters Stephen P , Lichtenstein Lawrence M , Hubbard Walter , Yancey Kim B , Stevenson Henry C , Miller Paul J , MacGlashan Donald W 
Published: January 2018

Abstract
We have examined the release of histamine and LTC4 from purified human basophils challenged with several different stimuli, both physiological and nonphysiological. Basophils (n=16) challenged with 0.1 μg/ml anti-IgE released 38±4% of their available histamine and 39±12 ng LTC4/109 basophils within 15-30 min. F-Met peptide (n=8) caused the release of 54±8% histamine and 42±25 ng LTC4/106 basophils within a period of 2-6 min. C5a caused the release of 22±3% histamine from selected donors but failed to initiate any LTC4 release unless combined with D2O or 5 mM extracellular calcium. The two nonphysiological stimuli A23187 and TPA caused extensive histamine release, 67±8 and 82±11%, respectively, and while A23187 initiated a large and rapid release of leukotriene, TPA failed to release any LTC4 even when combined with D2O or 2-5 mM extracellular calcium. Increased concentrations of extracellular calcium enhanced anti-IgE and f-Met peptide induced release of LTC4 but inhibited the A23187 induced release of leukotriene. A single peak of immunoreactive leukotriene C4 that comigrated with the authentic standard was identified using HPLC followed by radioimmunoassay. No LTD4 or LTE4 could be detected. Purified human basophils incubated with 0.2 μM [3H]AA incorporated 290 pmol/106 cells, or 32±5% of the available label within 60 min. The [3H]AA was taken principally into the phospholipids (73±5%), with 20±3% as neutral lipid, and only 5±2% remaining as the free acid. Three phospholipid subclasses, phosphatidylcholine, PC (24±2%), phosphatidylinositol, PI (22±1%), and phosphatidytethanolamine, PE (15±3%), accounted for the majority of the incorporated [3H]AA while the remainder of the phospholipids accounted for less than 5% of the total cpm. HPLC analysis of the lipid mediators released during stimulation with 0.1 μg/ml anti-IgE revealed [3H]LTC4 (2.4±1.0%), [3H]5HETE (1.0±0.1%), unmetabollzed [3H]AA (91±2%), and an unidentified peak (3.4±1.4%). The unknown metabolite eluted with the prostaglandins, was inhibited by indomethacin, and appeared to have a relatively high specific activity. It may thus represent an artifact of the labeling procedure rather than a novel basophil-derived prostaglandin.
Change of Membrane Fluidity of Rat Neutrophils Accompanying Escherichia coli Inoculation
Authors: Masuda Midori , Komiyama Yutaka , Nishikado Hiroyuki , Kuriki Hideki , Egawa Hiroshi , Murata Kenjiro 
Published: January 2018

Abstract
Membrane fluidity of rat neutrophils was studied following Escherichia coli inoculation, and characteristic changes were observed. Membrane fluidity was assessed by the excimer-forming lipid technique using pyrenedecanoic acid and flow cytometry and expressed as the fluorescence intensity ratios of excimer and monomer pyrenedecanoic acid (lE/LM ratio). High lE/lM ratios indicated high membrane fluidity. The IE/Im ratio of rat neutrophils (0.50 ± 0.048) increased after E. coli inoculation, reaching a maximum of almost 1.00 after 10-20 min and then returning to its starting value. Intravenous injection of heat-killed E.coli or E. coli-conditioned culture supernatants into rats induced a rapid increase of lE/lM ratios, which returned to initial levels after 20 min. The effect on membrane fluidity of in vitro neutrophil incubation with E. coli, heat-killed E. coli, or E. coli conditioned culture supernatants was similar to that observed in vivo. Addition of 5 mM ethylenediaminetetraacetic acid (EDTA) did not affect neutrophil membrane fluidity. Addition of either 5 μg/ml cytochalasin B or 10-5 M colchicine did not directly affect neutrophil membrane fluidity but did block the change observed following incubation with bacteria.