Search results for "Phorbol"
showing 10 items of 131 documents
Deep venous thrombosis: Behaviour of the polymorphonuclear leukocyte integrin pattern at baseline and after in vitro activation
2005
In a group of 18 subjects with acute deep venous thrombosis (DVT), evidenced by clinical examination and echo-color-Doppler, we examined the phenotypical expression of the polymorphonuclear leukocyte (PMN) beta2-integrins (CD11a, CD11b, CD11c, CD18), obtained by using a flow cytofluorimeter. The evaluation was performed before and after in vitro activation (prolonged for 5 and 15 minutes) with 4-phorbol 12-myristate 13-acetate (PMA) and N-formyl-methionyl-leucyl-phenylalanine (fMLP). In DVT subjects, at baseline, the phenotypical expression of CD11b was decreased and that of CD11c was increased when compared with normal controls; no difference was found in CD11a and CD18 expression. In norm…
Polymorphonuclear leukocyte membrane fluidity before and after activation in subjects with insulin resistance.
2000
The aim of this research was the evaluation of polymorphonuclear leukocyte (PMN) membrane fluidity in subjects with insulin resistance. Insulin sensitivity, in fact, may be influenced by plasma membrane fluidity. We enrolled 19 subjects with insulin resistance previously demonstrated during an euglycemic hyperinsulinemic clamp. PMN membrane fluidity was studied by labeling intact cells with the fluorescent probe 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene and calculating the fluorescence polarization degree. The measurement was made before and after incubation of PMNs with two activating agents: 4-phorbol 12-myristate 13-acetate (PMA) and N-formyl-methionyl-leucyl-phenylalanine (…
Stimulus-Dependent Increased Generation of Oxygen Intermediates in Monocytes and Polymorphonuclear Leukocytes in Psoriasis
1985
Based on recent findings indicating increased respiratory burst activity of monocytes (M phi) and polymorphonuclear leukocytes (PMN) in psoriasis upon stimulation with zymosan particles, we examined the question of whether incubation with various stimuli always results in augmented oxidative metabolism in psoriatic phagocytes. We compared M phi and PMN isolated from the peripheral blood of 12 patients with psoriasis and 12 control individuals. We measured the generation of oxygen intermediates of resting and stimulated M phi and PMN by luminol-enhanced chemiluminescence. The stimulants applied were: (1) aggregated immunoglobulin (aggIg), (2) zymosan, (3) zymosan opsonized with autologous se…
Diabetes mellitus: Polymorphonuclear leukocyte (PMN) filtration parameters and PMN membrane fluidity after chemotactic activation
1999
Abstract The goal of this research was to determine leukocyte rheology at baseline and after chemotactic activation in type I and type II diabetics. In 19 normal subjects, 21 type I diabetics, and 16 type II diabetics at baseline and after in vitro chemotactic activation (prolonged for 5 and 15 minutes) with two stimulating agents (4-phorbol 12-myristate 13-acetate [PMA] and N -formyl-methionyl-leucyl-phenylalanine [fMLP]), we evaluated polymorphonuclear (PMN) filtration parameters (using a St. George filtrometer [Carri-Med, Dorking, UK] and considering the initial relative flow rate [IRFR] and the concentration of clogging particles [CP]) and PMN membrane fluidity (obtained by marking PMNs…
Activation of classical protein kinase C decreases transport via systems y+and y+L
2007
Activation of protein kinase C (PKC) downregulates the human cationic amino acid transporters hCAT-1 (SLC7A1) and hCAT-3 (SLC7A3) (Rotmann A, Strand D, Martiné U, Closs EI. J Biol Chem 279: 54185–54192, 2004; Rotmann A, Vekony N, Gassner D, Niegisch G, Strand D, Martine U, Closs EI. Biochem J 395: 117–123, 2006). However, others found that PKC increased arginine transport in various mammalian cell types, suggesting that the expression of different arginine transporters might be responsible for the opposite PKC effects. We thus investigated the consequence of PKC activation by phorbol-12-myristate-13-acetate (PMA) in various human cell lines expressing leucine-insensitive system y+[hCAT-1, h…
Inhibitory effects of N-acetylcysteine on superoxide anion generation in human polymorphonuclear leukocytes.
1997
Abstract It has been suggested that reactive oxygen species released by activated polymorphonuclear leukocytes (PMN) in man is one mechanism of tissue injury. Therapeutic action aimed at increasing antioxidant defence mechanisms is still a clinical challenge. This study examines the activity of N-acetylcysteine, a known antioxidant, in the protection of PMN exposed in-vitro to the chemoattractant peptide fMet-Leu-Phe (FMLP), the protein kinase C activator phorbol myristate acetate or the lipid peroxidation promoter t-butyl hydroperoxide. FMLP (3–300 nm) and phorbol myristate acetate (160 pm–160 nm) induced concentration-related superoxide anion generation. Pre-treatment with N-acetylcystein…
Effect of selected triterpenoids on chronic dermal inflammation.
1997
The activity of four natural triterpenoids on a 12-O-tetradecanoylphorbol-13-acetate multiple-dose model of skin chronic inflammation was studied. Erythrodiol and ursolic acid were significantly effective. The most important features concerning structure-activity relationship and previous data on the effect of these triterpenoids on other inflammatory conditions are discussed.
Modulation of COX, LOX and NFκB activities by Xanthium spinosum L. root extract and ziniolide.
2012
Xanthium spinosum L. (Asteraceae) is a medicinal weed distributed worldwide. Many of its diverse ethnopharmacological uses - namely diarrhoea, inflammation, liver disorders, snake bite and fever - are linked - at least in part - to an uncontrolled release of arachidonic acid metabolites. The crude extract of X. spinosum roots from Jordanian origin dose-dependently inhibited the 5-LOX (IC50 is approximately equal to 10 μg/mL), COX-1(IC50 is approximately equal to 50 μg/mL), and 12-LOX (IC50 is approximately equal to 170 μg/mL) enzymatic pathways in intact pro-inflammatory cells. A direct activity at the level of PLA2 is not probable, but the extract induced the synthesis of the anti-inflamma…
Zanhasaponins A and B, Antiphospholipase A2 Saponins from an Antiinflammatory Extract of Zanha africana Root Bark
1997
A MeOH extract from Z. africana was examined for topical antiinflammatory activity and proved to be active against arachidonic acid (AA) acute edema, 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced chronic inflammation, and oxazolone delayed-type hypersensitivity in mice. The extract also showed significant inhibitory activity of Naja naja phospholipase A2 when a polarographic method was used. Two oleanane-type triterpene saponins, zanhasaponins A (1) and B (2), and the cyclitol pinitol (4), isolated from the extract, were active as inhibitors of PLA2. A further saponin, zanhasaponin C (3) was inactive in this assay.
Different response of TH1 cells for stimulation with anti-CD3 antibodies.
1990
In this report, evidence is provided for a further subdivision of CD4+ T helper cell lines. The earlier definition of the TH1 and TH2 subtypes was confirmed by their differential response to interleukin (IL) 1. An additional subdivision of the TH1 subset was revealed when TH1 cell lines were costimulated with anti-CD3 antibodies and IL2. The IL2-induced proliferation of three of the resulting TH1 lines was blocked by anti-CD3 antibodies. By contrast, no such block was observed in a fourth TH1 cell line. In all four lines anti-CD3 triggering caused production of IL2. The block of proliferation was reversed neither by antigen-presenting cells nor by phorbol 12-myristate 13-acetate, a protein …