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Biomedical subjects

E Razin

Publications and source records attributed to E Razin.

At least 55 records · Page 3Linked to original sources

Thrombin-mast cell interactions. Binding and cell activation.

Activation of mouse bone marrow-derived mast cells (BMMC) by thrombin (0.05-0.5 U/million cells) resulted in a concentration-dependent release of histamine, which levelled off by 0.1 U thrombin. Rat peritoneal mast cells (RMC) were not stimulated by thrombin, though in control experiments, both types of mast cells degranulated upon exposure to IgE-antigen. Pretreatment of thrombin with 0.2 mM diisopropylfluorophosphate (DFP), a specific serine protease inhibitor, resulted in 90% loss of thrombin degranulation and coagulant activity. Fluorescently labelled thrombin (FITC-thrombin) specifically bound to the BMMC surface, as measured by fluorescence cytometry. Pre-exposure of the BMMC to 20-fold excess of unlabelled thrombin prior to incubation with FITC-thrombin, prevented the binding of the labelled-thrombin to the cells. Incubation of thrombin with DFP or with antithrombin III (AT-III) resulted in losses of procoagulant and of BMMC degranulatory activities. DFP treatment of FITC-thrombin had no effect on the binding of the labelled enzyme to the cell surface. However, preincubation of the FITC-thrombin with AT-III prevented thrombin binding to the BMMC. Thus, the binding and the catalytic regions of the thrombin molecule are operationally distinct from one another. Kinetic analysis of the BMMC exposed to 0.5 U thrombin revealed a transient rise in intracellular cAMP, which peaked by 15 sec and was not measurable after 1 min. This suggests that differential activation of mast cells can occur at sites of tissue injury.

Animals↗

Thrombin-induced degranulation of cultured bone marrow-derived mast cells: effect on calcium uptake.

The role of calcium in the mechanism of thrombin activation of bone marrow-derived mast cells (BMMC) was explored by measuring the changes in the uptake of 45Ca2+ into quiescent BMMC and into cells stimulated by thrombin or by IgE-antigen. The results indicate that activation of BMMC by either thrombin or IgE-antigen is Ca2+-dependent. One million BMMC, activated by 0.05-5 U thrombin, accumulated 45Ca2+ in a concentration-dependent manner, which levelled off at around 1 U thrombin. Extracellular 45Ca2+ uptake of thrombin-stimulated cells is saturable within 90 seconds and corresponds to the kinetics of histamine release, whereas that of IgE-antigen exposed cells continues unabated for over 5 min. The pattern of 45Ca2+ uptake of IgE-sensitized BMMC exposed to thrombin suggests that the pro-stimulatory locus of thrombin action on the surface membrane is distinct from that of IgE.

Animals↗

Activation of the 5-lipoxygenase pathway in E-mast cells by peanut agglutinin.

Mouse E-mast cells were differentiated and grown by culturing bone marrow cells in medium containing WEHI-3-conditioned medium. These cells possess surface receptors to the following agglutinins: peanut (PNA), concanavalin A (Con A), and soybean (Sb). One to 200 micrograms of PNA/10(6) E-mast cells selectively stimulated the generation of leukotriene C4 (LTC4) in the absence of beta-hexosaminidase release. Exposure of 10(6) E-mast cells to 1 to 200 micrograms Con A or Sb had no effect either on preformed mediator release or on the generation of leukotrienes. LTC4 was quantitated by integrated UV absorbance after resolution by reverse phase high pressure liquid chromatography. The optimum release of LTC4 (13.2 ng/10(6) cells) was achieved by 50 micrograms of PNA/10(6) cells. The response is characterized by the inhibition by excess amounts of PNA. The amount of LTC4 generated during optimal PNA stimulation is lower than the amount produced after stimulation by IgE-antigen or by calcium ionophore A23187 (19.8 ng and 148 ng, respectively). The release of LTC4 began within 5 min after PNA stimulation, and reached a plateau within 45 to 60 min at 37 degrees C. This kinetic pattern is similar to that observed after calcium ionophore A23187 stimulation of these cells. The results suggest that PNA is capable of selectively activating the 5-lipoxygenation of arachidonic acid without affecting beta-hexosaminidase secretion. Apparently, separate biochemical events may serve to mobilize each class of mediators.

Animals↗

Interleukin 3: A differentiation and growth factor for the mouse mast cell that contains chondroitin sulfate E proteoglycan.

Mouse mast cells were differentiated and grown by culturing bone marrow cells in medium containing 2 X 10(-10) M purified interleukin 3 (IL 3). The cells obtained were similar in ultrastructure, membrane antigen phenotype, proteoglycan type, and lipid products generated upon immunologic activation to mast cells differentiated in culture by WEHI-3-conditioned medium (WEHI-3-CM) and by concanavalin A (Con A) splenocyte-conditioned medium. Phenotypically, these cells expressed IgE receptors and H-2 antigens and were recognized by a monoclonal antibody (B23.1) that did not react with mouse serosal heparin-containing mast cells. The classic phenotypic markers of mouse T cells or macrophages were not detected. The mouse mast cells differentiated with IL 3 as well as those differentiated in WEHI-3-CM incorporated [35S]sulfate into a nonheparin proteoglycan of 150,000 to 200,000 m.w. Most of the 35S-labeled macromolecules were degraded by chondroitinase ABC to yield only two disaccharides, which co-chromatographed on ascending thin layer chromatography with delta Di-4S and delta Di-diSE; thus, the proteoglycan in these cells is composed of chondroitin sulfate E glycosaminoglycans. After sensitization with monoclonal IgE, washing, and antigen activation, the IL 3 differentiated cells released the preformed mediator beta-hexosaminidase and generated and released two major classes of lipid mediators. The quantities of leukotriene C4 (LTC4), leukotriene B4 (LTB4), and platelet-activating factor (PAF-acether) generated/10(6) cells were 17, 3.0, and 3.1 ng, respectively. The ratio of these three lipid mediators was similar to that obtained from mast cells differentiated in WEHI-3-CM and in Con A-conditioned medium. Thus, T cell-derived IL 3 is the component present in the conditioned media that is required for differentiation and growth of the subclass of mast cells containing chondroitin sulfate E proteoglycan, designated E-MC. The IL 3-dependent E-MC may represent the in vitro counterpart of the T-cell-dependent mucosal mast cell, suggesting in turn that the production of LTC4 and LTB4 and of PAF-acether may play a role in adaptive intestinal immunity to helminthic parasites.

Animals↗

Thrombin-induced degranulation of cultured bone marrow-derived mast cells.

This study was undertaken to determine if a plasma protease such as thrombin, a highly specific procoagulant enzyme that has numerous effects on platelets, endothelial cells, and smooth muscle cells, could mediate mast cell activation processes. Our results indicate that at near physiologic levels, thrombin can rapidly trigger mast cell degranulation without activating the 5-lipoxygenase system.

Animals↗

An analysis of the relationship between 5-lipoxygenase product generation and the secretion of preformed mediators from mouse bone marrow-derived mast cells.

The quantitative relationships between the secretion of a granule-associated mediator, beta-hexosaminidase, and the oxidative metabolism of arachidonic acid by the 5-lipoxygenase pathway were analyzed for a homogeneous population of T cell-dependent, bone marrow-derived, murine mast cells. The mast cells were either sensitized with a monoclonal IgE and challenged with specific antigen, or to bypass a transmembrane signal, were stimulated with calcium ionophore A23187. The released products of the 5-lipoxygenase pathway were quantitated by integrated ultraviolet absorbance after resolution by reverse phase-high performance liquid chromatography in the case of 5-hydroxy-eicosatetraenoic acid (5-HETE), and by separate radioimmunoassays for leukotriene C4 (LTC4) and leukotriene B4 (LTB4). The activation-release response of the cells was perturbated by the introduction of three pharmacologic agents, each directed to different steps in the 5-lipoxygenase pathway of arachidonic acid metabolism, and the action of each agent was determined for separate cell samples while present and after its removal by washing. 5,6-Dehydroarachidonic acid (5,6-DHA), an irreversible inhibitor of 5-lipoxygenase, prevented formation of 5-HETE from exogenous [14C]arachidonic acid and from membrane-derived arachidonic acid in a dose-related fashion when sensitized mast cells, preincubated with drug, were washed before antigen activation. Release of 5-HETE, LTC4, and LTB4 was inhibited by 5,6-DHA in a corresponding dose-related fashion, with a minimal preincubation period of 1 to 5 min before the cells were washed and subjected to antigen-dependent activation. In contrast, the inhibitory effect of 5,6-DHA on beta-hexosaminidase release was lost after three washes and was not evident after one wash unless the preincubation period was extended to 15 min. The capacity of 5,6-DHA to prevent leukotriene generation without altering beta-hexosaminidase release was also observed with ionophore-activated mast cells. Preincubation of sensitized cells with diethylcarbamazine (DEC), followed by a wash before antigen-dependent activation, produced inhibition of leukotriene generation, no effect on beta-hexosaminidase release, and augmentation of 5-HETE release at the maximum dose studied; thus, DEC interrupts the pathway distal to the formation of 5-hydroperoxy-eicosatetraenoic acid (5-HPETE) from arachidonic acid by 5-lipoxygenase. Preincubation of sensitized cells with incremental amounts of the prostacyclin analog U-60,257, followed by washing and antigen challenge, inhibited LTC4 release without altering the release of LTB4 or beta-hexosaminidase.(ABSTRACT TRUNCATED AT 400 WORDS)

8,11,14-Eicosatrienoic Acid↗

Inhibition of proliferation of mouse T cell-dependent bone marrow-derived mast cells by rat serum does not change their unique phenotype.

Both mouse and rat sera have been found to inhibit proliferation in vitro of interleukin 3-dependent chondroitin sulfate E proteoglycan-containing mouse bone marrow-derived mast cells (BMMC), as assessed by quantitation of 3H-labeled thymidine incorporation into DNA, cell cycle analysis, and cell number. Rat serum (9%) inhibited 3H-labeled thymidine incorporation within 60 min of exposure in a culture medium composed of 1% fetal calf serum (FCS) and 16% concanavalin A splenocyte-conditioned medium. The anti-proliferative effect of rat serum did not alter cell viability for 17 hr of subsequent culture, was dose related, with a maximal effect at 7% rat serum, and was reversible. Cytofluorographic analysis of relative DNA content per cell revealed that the proportion of cells in the S + G2 + M phases of the cell cycle was decreased in cells treated with 9% rat serum compared with cells cultured in either 1% or 10% FCS. These rat serum-treated BMMC exhibited no change in plasma membrane antigen phenotype as assessed by 15 monoclonal antibodies, and continued to synthesize chondroitin sulfate E proteoglycan. When sensitized with monoclonal IgE antibody, washed, and challenged with specific antigen, the rat serum-treated BMMC released the preformed secretory granule-associated mediators beta-hexosaminidase and histamine, and the newly generated lipid mediators leukotriene C4 (LTC4) and leukotriene B4 (LTB4) in amounts comparable to BMMC cultured in 10% FCS. Thus, the unique cell surface phenotype, the presence of chondroitin sulfate E proteoglycan rather than heparin proteoglycan, and the generation of LTC4 and LTB4 in a ratio of approximately 6:1 upon perturbation of the IgE receptor are distinctive characteristics of the interleukin 3-dependent mouse BMMC subclass, and not a functional consequence of the rapid proliferation of the cell.

Animals↗

Cloned mouse mast cells derived from immunized lymph node cells and from foetal liver cells exhibit characteristics of bone marrow-derived mast cells containing chondroitin sulphate E proteoglycan.

Cloned mouse mast cells which were T cell growth-dependent were derived both from immunized lymph node and from foetal liver, and were found to be morphologically and biochemically similar to mast cells previously differentiated in vitro from mouse bone marrow (BMMC). These two T cell growth-dependent mouse mast cell clones were identical to the BMMC in their preferential synthesis of chondroitin sulphate E proteoglycan rather than heparin proteoglycan. The hydrodynamic size of the cell-associated proteoglycan from each of the three mast cell sources was 150,000-250,000 mol. wt.; and that of the covalently bound glycosaminoglycans was 13,000-25,000 mol. wt. Chondroitinase ABC digestion of the [35S]proteoglycans from both cloned mast cells, as well as the BMMC, yielded only two disaccharides which comigrated on ascending thin layer chromatography with delta Di-4S and delta Di-diSE standards, respectively. Quantification of the radioactivity in the enzyme digests revealed that one-sixth to one-half of the resulting disaccharides were disulphated, similar to that found in BMMC containing chondroitin sulphate E. When sensitized with monoclonal IgE, washed, and subsequently challenged with specific antigen, each of the two cloned mast cells generated more than 100 ng of leukotriene C4 (LTC4)/10(6) cells, but only 3-12 ng leukotriene B4 (LTB4)/10(6) cells, characteristics also observed for the BMMC. Based upon these observations, it is concluded that the cloned mast cells from lymph node and liver and the bone marrow-derived mast cell belong to a distinct subclass of mast cells. These mast cells have been designated E-mast cells (E-MC) in order to distinguish them from heparin-containing mast cells (H-MC).

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IgE-mediated release of leukotriene C4, chondroitin sulfate E proteoglycan, beta-hexosaminidase, and histamine from cultured bone marrow-derived mouse mast cells.

Mouse bone marrow-derived mast cells differentiated in vitro and sensitized with monoclonal IgE respond to antigen-initiated activation with the release of histamine, beta-hexosaminidase, chondroitin sulfate E proteoglycan, and leukotriene C4 (LTC4). The chondroitin sulfate E nature of the glycosaminoglycan side chain was established by demonstrating that the chondroitinase ABC disaccharide digestion products were composed of equal quantities of 4-sulfated and 4,6-disulfated N-acetyl-galactosamine. The single immunoreactive sulfidopeptide leukotriene, released and quantitated with a class-specific antibody, was identified as LTC4 by its retention time on reverse-phase high-performance liquid chromatography and by its specific spasmogenic activity on the guinea pig ileum. The release of the preformed mediators, as well as of LTC4, was related in a dose-response fashion to the concentration of monoclonal IgE used during the sensitization step and to the concentration of specific antigen used to initiate the activation-secretion response. The optimal concentrations of IgE for sensitization and of antigen for challenge were the same for the release of preformed mediators and of LTC4. In addition, the time courses of their release were superimposable, with a plateau at 5 min after antigen challenge. The release of three preformed mediators and of LTC4 after fixation of IgE, washing of the sensitized cells, and antigen challenge unequivocally indicates a bone marrow-derived mast cell origin for these products. Linear regression analyses of the net percent release of beta-hexosaminidase to histamine and of 35S-chondroitin sulfate E to beta-hexosaminidase yielded straight lines that intersected at the origin, which indicates that the three preformed mediators are localized in the secretory granules of the bone marrow-derived mast cells. The concomitant generation of 23 ng of LTC4/10(6) sensitized bone marrow-derived mast cells represents the first example of IgE-dependent release of substantial amounts of LTC4, a component of slow reacting substance of anaphylaxis, from a mast cell population of greater than 95% purity. The IgE-dependent generation of LTC4, rather than prostaglandin D2, by the chondroitin sulfate E proteoglycan-containing bone marrow-derived mast cells contrasts with the predominant generation of prostaglandin D2 by heparin proteoglycan-containing mast cells. These differences together support the existence of two phenotypically different mast cell subclasses.

Animals↗

Immunologic and ionophore-induced generation of leukotriene B4 from mouse bone marrow-derived mast cells.

Mouse bone marrow-derived mast cells differentiated in vitro and sensitized with monoclonal IgE respond to antigen-initiated activation-secretion with the generation of leukotriene B4 (LTB4), a highly potent chemotactic factor. The antigen-initiated net percent release of the secretory granule marker beta-hexosaminidase and the generation of immunoreactive LTB4 and of immunoreactive leukotriene C4 (LTC4) were not diminished by washing the cells before challenge, indicating that interaction of the antigen occurred with the IgE fixed on cell membranes and was not due to phagocytosis of immune complexes formed in the fluid phase. The parallel dose-response relationship for the antigen-induced release of the performed mediator and the generation of both leukotrienes along with the superimposable time courses of their extracellular appearance indicate the origin of these mediators from a common cell type with IgE receptors. Resolution by reverse phase-high performance liquid chromatography (RP-HPLC) of the leukotrienes released from unsensitized cells by ionophore A23187 and from sensitized cells by the specific antigen revealed that the generation of LTB4 was accompanied by the production of the two diastereoisomers of 6-trans-LTB4, which were not immunoreactive. The immunoreactive LTB4 eluted from RP-HPLC at the same retention time as synthetic LTB4 was present in similar nanogram quantities when measured by either radioimmunoassay or integrated absorbance at 269 nm and exhibited a chemotactic activity for human neutrophils on a weight basis comparable to that of synthetic LTB4. The overall recoveries after RP-HPLC of immunoreactive LTB4 released from ionophore A23187-activated, bone marrow-derived mast cells and of added tritiated synthetic LTB4 in separate experiments with ionophore-activated cells were comparable and greater than 78%. The maximum generation of LTB4 by ionophore A23187-activated cells of 7.9 +/- 2.5 ng/10(6) cells (mean +/- SD), occurring at 40 min, was greater than the maximum generation of 4.5 +/- 0.8 ng/10(6) cells, with immunologic stimulation occurring 5 min after antigen challenge of sensitized cells. The initial rate of LTB4 generation after perturbation of the IgE-Fc receptors, however, exceeded that following ionophore A23187 stimulation and may represent one important variable in establishing a significant chemotactic gradient.

Animals↗

Antigen-initiated release of platelet-activating factor (PAF-acether) from mouse bone marrow-derived mast cells sensitized with monoclonal IgE.

Mouse bone marrow mast cells sensitized with monoclonal IgE and activated with specific antigen released 2.8 +/- 0.5 ng of platelet-activating factor (1-0-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine) (PAF-acether)/ 10(6) cells. The PAF-acether was identified by its ability to aggregate fully aspirin-treated washed rabbit platelets in the presence of an adenosine diphosphate (ADP)-scavenger complex, by its co-chromatography with [3H]-labeled semi-synthetic PAF-acether and synthetic 1-0-octadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine, and by its inactivation by phospholipases A2, C, and D and not by lipase A1. The antigen-initiated release of PAF-acether, leukotriene C4 (LTC4), and leukotriene B4 (LTB4), and the secretion of the granule marker beta-hexosaminidase were not diminished by washing the cells before challenge, indicating that they were due to the interaction of antigen with the IgE fixed on the cell membrane and not to phagocytosis of immune complexes formed in the fluid phase. The parallel antigen-induced dose-response relationship, along with the superimposable time-course of the extracellular appearance, of beta-hexosaminidase, PAF-acether, and both leukotrienes indicated that the origin of these diverse mediators was from a common cell type with IgE-Fc receptors. Ethanol extraction of antigen-stimulated bone marrow-derived mast cells revealed the early transient appearance of a cell-associated platelet-aggregating activity, the action of which on platelets, like PAF-acether, was independent of ADP and arachidonic acid metabolism. The cell-associated activity contained a novel product that eluted at 13 min during high performance liquid chromatography (HPLC) (solvent hexane:n-propanol:water, 46:46:8), permitting resolution from PAF-acether and lyso-PAF-acether (1-O-alkyl-sn-glyceryl-3-phosphorylcholine), which eluted at 29 min and 30 min, respectively. The cell-associated material, which differs from lyso-PAF-acether, the putative precursor of PAF-acether, in being active in the bioassay on platelets may represent a newly recognized intermediate in the generation of PAF-acether. As the transiently present cell-associated intermediate has not been previously recognized, its detection may depend upon the relatively unique properties of the bone marrow-derived mast cell system in which IgE-dependent activation leading to product generation is complete within 5 min.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Culture from mouse bone marrow of a subclass of mast cells possessing a distinct chondroitin sulfate proteoglycan with glycosaminoglycans rich in N-acetylgalactosamine-4,6-disulfate.

A differentiated population of cells with metachromatically staining granules and surface IgE receptors was obtained from mouse bone marrow cultured for 2 weeks in the presence of conditioned medium derived from concanavalin A-stimulated splenocytes. The cells were found to incorporate large amounts of [35S]sulfate into an intracellular 35S-labeled proteoglycan of Mr approximately 200,000 containing a maximum of seven glycosaminoglycan side chains (Mr = 25,000). After chondroitinase ABC treatment of density gradient-purified [3H] serine-labeled proteoglycan, the resulting core was Mr approximately 26,000 as assessed by gel filtration. Two-dimensional cellulose acetate electrophoresis of beta-eliminated 35S-labeled glycosaminoglycan revealed a single type of glycosaminoglycan that migrated at the position of oversulfated chondroitin sulfate E from squid cartilage. Chondroitinase ABC degradation of the 35S-labeled glycosaminoglycan yielded two cleavage products in approximately equal molar amounts which co-migrated in both descending paper chromatography and high voltage paper electrophoresis with a monosulfated disaccharide, 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose, and a disulfated disaccharide, 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-4-6-di-O-sulfo-D-galactose. The release of some free [35S]sulfate from the oversulfated disaccharide with either chondro-4-sulfatase or chondro-6-sulfatase and the complete desulfation by their combined action established that the oversulfated disaccharide contained N-acetylgalactosamine-4,6-disulfate. The 35S]labeled proteoglycan of these unique IgE receptor-bearing and histamine-containing cells, therefore, is composed of chondroitin sulfate E rather than heparin glycosaminoglycan, and thus is the first identification of such an intracellular localized proteoglycan in a mammalian cell.

Acetylgalactosamine↗

Indomethacin modulates plasma membrane-associated properties of macrophages.

Changes in the plasma membrane of macrophages treated with indomethacin were investigated. A significant decrease in the binding of IgG was observed with indomethacin-treated cells, as compared to the control group. Electron microscopic examination did not show any significant morphological differences between the indomethacin treated macrophages and the controls. It was found, however, that indomethacin treatment resulted in a drastic increase in the binding capacity of the cell membrane to cationized ferritin. It is suggested that indomethacin may have a modulating effect on the macrophage plasma membrane.

Animals↗

Generation of leukotriene C4 from a subclass of mast cells differentiated in vitro from mouse bone marrow.

Bone marrow-derived mast cells, differentiated in vitro, demonstrate surface IgE, receptors and contain histamine in metachromatic granules, which are composed of chondroitin sulfate E proteoglycan rather than heparin proteoglycan. Activation of this subclass of mast cells with calcium ionophore A23187 resulted in generation of immunoreactive C-6-sulfidopeptide leukotriene in a dose- and time-dependent fashion. Isolation of immunoreactive C-6-sulfldopeptide leukotriene by reverse-phase high-performance liquid chromatography (RP-HPLC) revealed a retention time and a specific biologic activity identical to those of synthetic leukotriene C4 (LTC4). Neither radiolabeled nor immunoreactive conversion products of [3H]LTC4/LTC4 were recognized during RP-HPLC resolution of the supernatants. The failure of fresh bone marrow cultures to generate C-6-sulfidopeptide leukotriene in response to ionophore indicates that leukotriene generation is dependent upon cellular differentiation into a mast cell population. The amount of LTC4 generated during optimal ionophore stimulation, 90.9 +/- 7.5 ng per 10(6) cells, contrasts with the relatively low amounts of C-6-sulfidopeptide leukotriene generated by the conventional heparin-containing rat mast cells or mouse mastocytoma cells.

Animals↗

Studies on the exocytosis of cultured mast cells derived from mouse bone marrow.

Mast cells were obtained from mouse bone marrow cells cultured for 14 days in medium derived from Concanavalin A (Con A) stimulated mouse spleen cells. Upon passive sensitization of the cultured cells with immunoglobulin E (IgE), histamine release from mast cells was approximately 200% above control within 1 min of incubation with anti-IgE. The calcium inonophore A 23187 also evoked a concentration-dependent (10(-8) M to 6 x 10(-7) M) histamine release following a 6 min incubation. Transmission electron microscopy (TEM) demonstrated that the secretory granules of the cultured cells have a peripheral crystalline pattern, like that previously demonstrated for mast cells. Scanning electron microscopy (SEM) illustrated spherical cells with surfaces traversed by many ridge-like folds. Intragranular fusion, following exposure of the IgE-bearing cells to anti-IgE, led to accumulation of the granules into channels which, on study with both transmission and scanning electron microscopy, appeared to be associated with the cell surface.

Animals↗

Effects of indomethacin treatment of human peripheral blood monocytes.

Indomethacin treatment (3-8 daily doses of 100 mg) to patients resulted in an increased level of peripheral blood monocytes, as compared to the initial values measured in each individual subject before taking the drug. Normal levels were resumed after the treatment stopped. The idea that these observations were related to the drug treatment per se and not superimposed by the arthritis was verified by the fact that similar results were obtained in healthy volunteers taking this drug.

Adult↗

Effects of indomethacin on hematopoiesis in mice.

The effect of indomethacin treatment on hematopoiesis in mice was examined. Twenty-four hours following the onset of treatment there was 3-fold increase in bone marrow non-specific esterase positive cells (NEPC) as compared to the initial level. Two days later a two-fold increase in spleen and peritoneal NEPC was observed. In all the organs examined, NEPC returned to its basal level after cessation of treatment. The increase in number of NEPC was accompanied by an elevation in CSF production. The effect of indomethacin on peripheral blood cells was also determined. A significant decrease in hematocrit level was found following the treatment. In addition, it was further found that following the drug treatment there was a significant reduction of erythrocyte number and hemoglobin levels.

Animals↗