scholarly journals Bacterial lipopolysaccharides prime macrophages for enhanced release of arachidonic acid metabolites.

1986 ◽  
Vol 164 (1) ◽  
pp. 165-179 ◽  
Author(s):  
A A Aderem ◽  
D S Cohen ◽  
S D Wright ◽  
Z A Cohn
Keyword(s):  
Arachidonic Acid ◽  
Peritoneal Macrophages ◽  
Lag Phase ◽  
Maximal Concentration ◽  
Latex Beads ◽  
Primed State ◽  
Acid Metabolites ◽  
Bacterial Lipopolysaccharides ◽  
Time Required ◽  
Kinetics Of

Preincubation of resident peritoneal macrophages with 10-100 ng/ml LPS for 60 min resulted in the cells becoming primed for enhanced (three-to eightfold higher) arachidonic acid (20:4) secretion in response to a variety of triggers. The half-maximal concentration of LPS required for priming was 10 ng/ml irrespective of whether the trigger was particulate (examples: zymosan or immune complexes) or soluble (such as PMA or A23187). Similarly, the time required for half-maximal priming of macrophages was 20 min irrespective of which trigger was used. The primed state persisted for at least 30 h. LPS-priming of macrophages also affected the kinetics of 20:4 metabolite secretion. The lag phase characteristically observed when 20:4 secretion is triggered was reduced in LPS-primed cells. Furthermore, LPS-primed cells secreted 20:4 metabolites when challenged with latex beads, while unprimed cells did not. These data suggest that stimuli such as zymosan, which elicit 20:4 secretion in macrophages, promote two signals, a priming signal and a triggering signal. LPS is capable of establishing the priming signal but not the triggering signal, while latex promotes the triggering signal but is unable to prime the cells for 20:4 release. LPS did not effect the profile of 20:4 metabolites secreted in response to any of the triggers, nor did it effect the profile of products synthesized from exogenously added 20:4, suggesting that it did not regulate the 20:4 cascade at the level of either the cyclooxygenase or lipoxygenase pathways. Macrophages respond to LPS without the intervention of T lymphocytes, since the macrophages from nude mice could be primed for enhanced 20:4 secretion.

scholarly journals Regulation of arachidonic acid metabolites in macrophages.

1980 ◽  
Vol 152 (2) ◽  
pp. 324-335 ◽  
Author(s):  
W A Scott ◽  
J M Zrike ◽  
A L Hamill ◽  
J Kempe ◽  
Z A Cohn
Keyword(s):  
Arachidonic Acid ◽  
Time Course ◽  
Quantitative Measure ◽  
Detailed Examination ◽  
Peritoneal Macrophages ◽  
Continuous Exposure ◽  
Mole Percent ◽  
Acid Metabolites ◽  
Kinetics Of

The lipids of mouse peritoneal macrophages contain high levels (25 mole percent) of esterified arachidonic acid (20:4). Following in vitro exposure to unopsonized zymosan, these cells synthesize and release oxygenated products of 20:4. Maximal levels of zymosan ingestion promote the release of 40-50% of the 20:4 content of cultures without loss of viabilitiy. Release of radiolabel from macrophages prelabeled with [3H]20:4 provides a quantitative measure for the synthesis of 20:4-derived products. Approximately 67% of the released 20:4 is recovered as prostaglandins (PG) (51% PGE and 16% 6-oxo-PGF1 alpha) and the remainder as apolar products tentatively identified as hydroxy-eicosatetraenoic acids. The kinetics of synthesis are comparable for both sets of products. A detailed examination of PGE synthesis indicated the PGE levels rise in parallel with phagocytosis during a continuous exposure of macrophages to zymosan. The concentration of particles determines the initial rate of PGE release, but the time-course of synthesis is finite (approximately 60 min), regardless of the zymosan dose. These observations are compatible with the notion that phagocytosis results in a burst of PG synthesis, the size of which is determined by the phagocytic stimulus. This is supported by the finding that secondary challenges of zymosan promote new rounds of PG synthesis by macrophages.

scholarly journals Biosynthesis of paf-acether. Paf-acether but not leukotriene C4 production is impaired in cultured macrophages

1989 ◽  
Vol 263 (1) ◽  
pp. 165-171 ◽  
Author(s):  
A Dulioust ◽  
E Vivier ◽  
N Meslier ◽  
R Roubin ◽  
I Haye-Legrand ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Nordihydroguaiaretic Acid ◽  
Peritoneal Macrophages ◽  
Adherent Cells ◽  
Leukotriene C4 ◽  
Intact Cells ◽  
Arachidonic Acid Metabolites ◽  
Acid Metabolites ◽  
C4 Production ◽  
Mouse Peritoneal Macrophages

After adherence for 24 or 48 h mouse peritoneal macrophages, upon a zymosan challenge, synthesized 114 +/- 55 and 82 +/- 31 pmol of paf-acether (paf)/mg of protein respectively, as compared with 513 +/- 195 pmol of paf/mg of protein in 2 h-adherent macrophages (means +/- S.D., n = 10). By contrast, 24 h- and 48 h-adherent macrophages exposed to zymosan produced more leukotriene C4 (2.7 +/- 1.1 and 1.4 +/- 0.2 nmol/mg of protein respectively, n = 5) than did 2 h-adherent macrophages (0.5 +/- 0.2 nmol/mg of protein, n = 5). Paf production was not altered when 2 h- and 24 h-adherent cells were cultured and/or stimulated in the presence of 5 microM-indomethacin, 10 microM-nordihydroguaiaretic acid or 100 microM-BW755C as compared with untreated cells. These results indirectly exclude the regulation of paf production by arachidonic acid metabolites. We investigated the efficiency of the enzymic steps which govern paf synthesis. We showed that the anabolic process was not impaired since (1) the amounts of alkylacylglycerophosphocholine and lyso-paf were similar in 2 h-, 24 h- and 48 h-adherent macrophages; (2) adding synthetic lyso-paf or acetyl-CoA to intact cells did not increase paf production in zymosan-stimulated 24 h- and 48 h-adherent macrophages; (3) the basal level of acetyltransferase was comparable in 2 h-, 24 h- and 48 h-adherent macrophages and in all cases was increased by 2-3 times upon zymosan challenge. We also showed that impaired paf production in 24 h- and 48 h-cultured macrophages was not due to the nature of the stimulus used to induce its synthesis.

scholarly journals Secretion of leukotriene C and other arachidonic acid metabolites by macrophages challenged with immunoglobulin E immune complexes.

1982 ◽  
Vol 156 (4) ◽  
pp. 1077-1086 ◽  
Author(s):  
C A Rouzer ◽  
W A Scott ◽  
A L Hamill ◽  
F T Liu ◽  
D H Katz ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Immune Complexes ◽  
Immunoglobulin E ◽  
Major Product ◽  
Cell Protein ◽  
Latex Beads ◽  
Arachidonic Acid Metabolites ◽  
Acid Metabolites

Resident mouse peritoneal macrophages release the slow-reacting substance leukotriene C (LTC) on exposure to particulate IgE immune complexes. Because these cells lose their responsiveness to an IgE stimulus after 4 h in culture, maximum release of 20:4 metabolites is observed before this time. However, a similar diminution in 20:4 metabolism was not observed with a zymosan stimulus. Freshly explanted cells are deficient in intracellular glutathione (GSH) (12.4 +/- 0.4 pmol/micrograms cell protein), but GSH increases to a steady state value of 30-35 pmol/micrograms of cell protein between 3 and 9 h of culture. Because GSH is required for the synthesis of LTC and prostaglandin (PG)E2, cultures challenged immediately after explanation have a diminished capacity to synthesize these 20:4 metabolites and release prostacyclin as the major product. By 4-5 h in culture, macrophages form significant amounts of LTC and PGE2. Under optimum conditions of maximum responsiveness to an IgE stimulus and GSH content (after 4 h of culture), macrophages challenged with latex beads coated with IgE immune complexes synthesize 1.0 +/- 0.3 pmol of LTC/microgram cell protein (60 +/- 18 pmol/10(6) cells) in addition to prostacyclin (8.2 +/- 0.8 pmol/micrograms cell protein) and PGE2 (4.7 +/- 1.5 pmol/micrograms cell protein). These amounts are quantitatively similar to the arachidonic acid metabolites produced by macrophages challenged with IgG immune complex-coated latex beads or zymosan. These data demonstrate that macrophages produce large quantities of LTC and other 20:4 metabolites in response to particle-bound IgE and antigen, provided that the appropriate in vitro conditions are met. The macrophage might, therefore, be a major source of slow-reacting substance and other 20:4 metabolites generated during IgE-mediated reactions in vivo.

Video-microscopic measurement of cell-substratum traction forces generated by locomoting keratocytes

1993 ◽  
Vol 51 ◽  
pp. 188-189
Author(s):  
Tim Oliver ◽  
Michelle Leonard ◽  
Juliet Lee ◽  
Akira Ishihara ◽  
Ken Jacobson
Keyword(s):  
Silicone Rubber ◽  
Molecular Motors ◽  
Video Frame ◽  
Traction Forces ◽  
Cell Traction Forces ◽  
Latex Beads ◽  
Cell Traction ◽  
Local Cell ◽  
Microscopic Measurement ◽  
Kinetics Of

We are using video-enhanced light microscopy to investigate the pattern and magnitude of forces that fish keratocytes exert on flexible silicone rubber substrata. Our goal is a clearer understanding of the way molecular motors acting through the cytoskeleton co-ordinate their efforts into locomotion at cell velocities up to 1 μm/sec. Cell traction forces were previously observed as wrinkles(Fig.l) in strong silicone rubber films by Harris.(l) These forces are now measureable by two independant means.In the first of these assays, weakly crosslinked films are made, into which latex beads have been embedded.(Fig.2) These films report local cell-mediated traction forces as bead displacements in the plane of the film(Fig.3), which recover when the applied force is released. Calibrated flexible glass microneedles are then used to reproduce the translation of individual beads. We estimate the force required to distort these films to be 0.5 mdyne/μm of bead movement. Video-frame analysis of bead trajectories is providing data on the relative localisation, dissipation and kinetics of traction forces.

Dose-Response Aggregometry in Maternal/Neonatal Platelets

1988 ◽  
Vol 60 (02) ◽  
pp. 314-318 ◽  
Author(s):  
A M A Gader ◽  
H Bahakim ◽  
F A Jabbar ◽  
A L Lambourne ◽  
T H Gaafar ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Dose Response ◽  
Lag Phase ◽  
Phase Slope ◽  
Multiple Doses ◽  
Nonpregnant Adult ◽  
Aggregation Of Platelets

SummaryThe aggregation of platelets collected from maternal/neonatal pairs (n = 240) at the time of childbirth, was studied in response to multiple doses of ADP, collagen, arachidonic acid and ristocetin. Similar responses were obtained from healthy nonpregnant adult controls for comparison. The lag phase, slope of the aggregation curves as well as maximum aggregation (MA%) were recorded and analysed. Neonatal and adult platelets exhibited more enhanced responses to decreasing doses of ADP, arachidonic acid and ristocetin, than maternal platelets. These enhanced responses were exhibited more consistantly in the slopes of the aggregation curves than in MA%. Although neonatal platelets have shown longer lag phase in their responses to collagen, the rate of the aggregation reaction was significantly faster than maternal platelets, with no differences in MA%. These results contradict many previous reports suggesting impaired aggregation responses of neonatal platelets to these agonist. The possible reasons for these contradictions were discussed.

Prothrombin Evaluation as Obtained by Kinetics Studies of Antigen-Antibody Reaction in a Laser Nephelometer

1984 ◽  
Vol 52 (01) ◽  
pp. 015-018 ◽  
Author(s):  
A Girolami ◽  
A Sticchi ◽  
R Melizzi ◽  
L Saggin ◽  
G Ruzza
Keyword(s):  
Liver Cirrhosis ◽  
Cirrhotic Patient ◽  
Maximum Rate ◽  
Serum Proteins ◽  
Clotting Factors ◽  
Kinetics Studies ◽  
Maximum Value ◽  
Time Required ◽  
Antigen Antibody ◽  
Kinetics Of

SummaryLaser nephelometry is a technique which allows the evaluation of the concentration of several serum proteins and clotting factors. By means of this technique it is also possible to study the kinetics of the reaction between antigen and antibody. We studied the kinetics of the reaction between prothrombin and an antiprothrombin antiserum using several prothrombins namely: Prothrombin Padua, prothrombin Molise, which are two congenital dysprothrombinemias, cirrhotic, coumarin or normal prothrombins. Different behaviors in the kinetics of the reactions were shown even when the concentration of prothrombins was about the same in all plasma tested. These differences were analyzed by means of a computer (Apple II 48 RAM) programmed to solve four unknown equations (Rodbard’s equation). From the data so obtained one can see that when voltages at the beginning and at the end of the reaction are in all cases about the same, a clear difference in the time required to reach half the maximum value of the voltage can still be demonstrated. This parameter, which is expressed in minutes, is longer in coumarin and prothrombin Molise than in controls. On the contrary it is shorter in prothrombin Padua and has about the same value of controls in the cirrhotic patient. Moreover the time at which the maximum rate is obtained is longer in coumarin and prothrombin Molise than in controls and shorter in liver cirrhosis and prothrombin Padua. In conclusion data obtained show that coumarin prothrombin behaves in a different way from cirrhotic prothrombin and also that there is a different behaviour between the two congenital dysprothrombinemias.

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