The N-formyl methionyl peptide, formyl-methionyl-leucyl phenylalanine (fMLF) increases the lateral diffusion of complement receptor 1 (CR1/CD35) in human neutrophils; a causative role for oxidative metabolites?

1996 ◽  
Vol 16 (5) ◽  
pp. 391-404 ◽  
Author(s):  
Birgitta J. Rasmusson ◽  
Jean-Louis Carpentier ◽  
Jean-Pierre Paccaud ◽  
Karl-Eric Magnusson
Keyword(s):  
Diffusion Constant ◽  
Lateral Diffusion ◽  
Free Radical Scavenger ◽  
Human Neutrophils ◽  
Radical Scavenger ◽  
Complement Receptor ◽  
Causative Role ◽  
Oxidative Metabolites ◽  
Mobile Fraction

The effects of the N-formyl methionyl peptide, formyl-methionyl-leucyl phenylalanine (fMLF) on the lateral mobility of the complement receptor type 1 (CR1/CD35) in glass-adherent human neutrophils were investigated, using fluorescence recovery after photobleaching (FRAP) and confocal microscopy (CSLM). It was found that addition of 0.1–1 μM fMLF increased the diffusion constant (D) of CR1/CD35 to 167–278% of controls. No effect was observed on the receptor distribution or the mobile fraction of receptors. The effect of fMLF on the lateral diffusion of CR1/CD35 could be totally inhibited by addition of pertussis toxin (PT, 250 ng/ml) or of the free radical scavenger enzymes superoxide dismutase (SOD, 2000 U/ml) and catalase (CAT, 200 U/ml), added together the results show that oxidative metabolites produced by neutrophils in response to fMLF can modulate CR1/CD35 diffusion, and indicate a regulatory role for oxygen radicals in phagocytosis.

scholarly journals Isolation and Characterization of Complement Receptor Type 1 (CR1) Storage Vesicles From Human Neutrophils Using Antibodies to the Cytoplasmic Tail of CR1

Blood ◽  
1997 ◽  
Vol 89 (12) ◽  
pp. 4555-4565 ◽  
Author(s):  
Anoopa Kumar ◽  
Erica Wetzler ◽  
Melvin Berger
Keyword(s):  
Indirect Evidence ◽  
Cytoplasmic Tail ◽  
Receptor Type ◽  
Human Neutrophils ◽  
Complement Receptor ◽  
Complement Receptor Type ◽  
Isolation And Characterization ◽  
Storage Vesicles ◽  
Complement Receptor Type 1

Abstract Neutrophil (PMN) activation is associated with increased surface expression of several membrane proteins that are translocated from intracellular pools. Indirect evidence suggests that the intracellular storage pools of complement receptor type 1 (CR1) in resting PMN are distinct from traditional granules and may be the secretory vesicles in which albumin is also stored, but it is not known if this compartment is homogeneous or heterogeneous. To isolate and characterize the CR1-containing vesicles, we used antibodies against unique sequences in the cytoplasmic tail of CR1. Affinity-purified IgG was used to adsorb CR1 storage vesicles from the light membrane fraction (γ-band) of nitrogen cavitates of resting PMN. The immunoadsorbent could quantitatively remove the CR1-containing vesicles, whereas control adsorbents with nonimmune IgG showed no specific binding of CR1. Immunoblots of specifically isolated vesicles also showed enrichment of albumin, decay-accelerating factor, FcγRIII, and CR3; whereas HLA class I was not detectable in these vesicles. Enzyme assay of specifically isolated vesicles after treatment with Triton X-100 showed that these vesicles contained most of the cells' latent alkaline phosphatase. An additional population of vesicles containing albumin, but not CR1, and that did not bind to anti-CR1 adsorbent was also identified. Immunoelectron microscopy showed that the specifically isolated vesicles had mean diameters of 0.086 to 0.1 μm and stained positive for CR1 and albumin. These results indicate that CR1 storage vesicles can be isolated with antibodies against the cytoplasmic tail of CR1 and show that these vesicles also contain albumin as well as glycosyl-phosphatidyl inositol-anchored proteins. These results are most compatible with the hypothesis that CR1-containing vesicles have arisen by endocytic retrieval of proteins that had been on the plasma membrane.

scholarly journals A Salen-Manganese Catalytic Free Radical Scavenger Inhibits Type 1 Diabetes and Islet Allograft Rejection

Diabetes ◽  
2004 ◽  
Vol 53 (10) ◽  
pp. 2574-2580 ◽  
Author(s):  
A. P. Olcott ◽  
G. Tocco ◽  
J. Tian ◽  
D. Zekzer ◽  
J. Fukuto ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Free Radical ◽  
Allograft Rejection ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Islet Allograft

Characterization of leukotriene B3: comparison of its biological activities with leukotriene B4 and leukotriene B5 in complement receptor enhancement, lysozyme release and chemotaxis of human neutrophils

1988 ◽  
Vol 74 (5) ◽  
pp. 467-475 ◽  
Author(s):  
Tak H. Lee ◽  
Tariq Sethi ◽  
Attilio E. G. Crea ◽  
Wilfried Peters ◽  
Jonathan P. Arm ◽  
...  
Keyword(s):  
Partial Agonist ◽  
Biological Activities ◽  
Leukotriene B4 ◽  
Human Neutrophils ◽  
Nuclear Magnetic Resonance Analysis ◽  
Complement Receptor ◽  
Resonance Analysis ◽  
Type 3

1. Leukotriene (LT) B3 was prepared by total chemical synthesis and its identity was confirmed by nuclear magnetic resonance analysis and proton homonuclear plot of connectivities and chemical shift assignments. The effects of LTB3 on complement receptor enhancement, chemotaxis and lysozyme release in human neutrophils (PMN) were compared with those of LTB4 and LTB5. 2. LTB3 and LTB4 elicited a virtually identical dose- and time-dependent enhancement in complement receptors type 1 (CR1) and type 3 (CR3) and release of lysozyme. LTB5 was approximately 100 times less potent than LTB4 in enhancing CR1 and CR3, whereas it was 10000 times less potent than LTB4 in releasing lysozyme from human PMN. 3. LTB3 and LTB5 were respectively 5- and 100-fold less potent than LTB4 in eliciting chemotaxis. 4. These findings indicate that the pro-inflammatory potential of LTB3 and LTB4 are similar, whereas LTB5 is substantially less potent as an inflammatory mediator. 5. The finding that LTB5 is a weak and partial agonist relative to LTB3 and LTB4 could be due to the rigidity of the C-17–C-18 double bond in LTB5. This may interfere with the active site specificity of LTB5 to a substantial extent. 6. One approach to the development of antagonists to the LTB4 receptor may be to establish a rigid structure in the C-17–C-18 region of the LTB4 molecule.

Melatonin reduces high levels of lipid peroxidation induced by potassium iodate in porcine thyroid

2019 ◽  
pp. 1-7 ◽  
Author(s):  
Paulina Iwan ◽  
Jan Stepniak ◽  
Malgorzata Karbownik-Lewinska
Keyword(s):  
Lipid Peroxidation ◽  
Oxidative Damage ◽  
Membrane Lipids ◽  
Chemical Properties ◽  
Iodine Concentration ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Protective Effects ◽  
Potassium Iodate ◽  
Hormone Synthesis

Abstract. Iodine is essential for thyroid hormone synthesis. Under normal iodine supply, calculated physiological iodine concentration in the thyroid is approx. 9 mM. Either potassium iodide (KI) or potassium iodate (KIO3) are used in iodine prophylaxis. KI is confirmed as absolutely safe. KIO3 possesses chemical properties suggesting its potential toxicity. Melatonin (N-acetyl-5-methoxytryptamine) is an effective antioxidant and free radical scavenger. Study aims: to evaluate potential protective effects of melatonin against oxidative damage to membrane lipids (lipid peroxidation, LPO) induced by KI or KIO3 in porcine thyroid. Homogenates of twenty four (24) thyroids were incubated in presence of either KI or KIO3 without/with melatonin (5 mM). As melatonin was not effective against KI-induced LPO, in the next step only KIO3 was used. Homogenates were incubated in presence of KIO3 (200; 100; 50; 25; 20; 15; 10; 7.5; 5.0; 2.5; 1.25 mM) without/with melatonin or 17ß-estradiol. Five experiments were performed with different concentrations of melatonin (5.0; 2.5; 1.25; 1.0; 0.625 mM) and one with 17ß-estradiol (1.0 mM). Malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA) concentration (LPO index) was measured spectrophotometrically. KIO3 increased LPO with the strongest damaging effect (MDA + 4-HDA level: ≈1.28 nmol/mg protein, p < 0.05) revealed at concentrations of around 15 mM, thus corresponding to physiological iodine concentrations in the thyroid. Melatonin reduced LPO (MDA + 4-HDA levels: from ≈0.97 to ≈0,76 and from ≈0,64 to ≈0,49 nmol/mg protein, p < 0.05) induced by KIO3 at concentrations of 10 mM or 7.5 mM. Conclusion: Melatonin can reduce very strong oxidative damage to membrane lipids caused by KIO3 used in doses resulting in physiological iodine concentrations in the thyroid.

OPTIMASI KONDISI EKSTRAKSI SENYAWA AKTIF ANTIOKSIDAN DARI BIJI ANGGUR

2019 ◽  
Vol 3 (2) ◽  
pp. 35
Author(s):  
Kartini Kartini ◽  
Azminah Azminah
Keyword(s):  
Free Radical ◽  
Optimum Condition ◽  
Active Compound ◽  
Grape Seed ◽  
Free Radical Scavenger ◽  
Water Bath ◽  
Radical Scavenger ◽  
Optimum Conditions ◽  
Ethanolic Solution ◽  
Reduced Pressure

In order to prepare standardized extract, optimization of extraction conditions of grape seed has been done. These conditions are type of menstrum (50, 70 and 96% of ethanolic solution), length of extraction (1, 2 and 4 hours) also method of evaporation (reduced pressure and opened air). Activity on free radical scavenger used as parameters to determine optimum conditions. Based on EC50 (concentration which scavenge 50% amount of free radical) can be concluded that optimum condition for extracting antioxidant active compound from grape seed are 70% ethanolic solution as menstrum, length of extraction 1 hour and evaporation on opened air use water bath.

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