Phorbol myristate acetate PMA

Experiments were conducted in which purified trichloroethylene (1 mg in acetone) was applied to the shaved backs of female ICR/Ha Swiss mice (Van Duuren et al. 1979). In an initiation-promotion study, a single application of trichloroethylene was followed by repeated application of phorbol myristate acetate (PMA) promoter. In a second study, mice were treated with trichloroethylene three times per week without a promoter. No significant tumor incidences were observed in these studies. Doses used in these studies were well below the maximum tolerated dose, which is often not reached in dermal studies. 

The phorbolester phorbol myristate acetate (PMA), which directly activates protein kinase C by bypassing receptor-coupled G-proteins, is the most potent stimulus that produces reactive oxygen species in human eosinophils. This sug-... 

In the classic model of initiation and promotion, conventional tumor promoters (CTP) inhibit the intracellular mechanisms that can eliminate the nascent clone, facilitate accumulation of the mutations necessary for full malignant transformation, or disrupt intercellular signaling [15], A classic example of a CTP is 12-O-tetradecanoylphorbol- l 3-acetate (TPA, also referred to as phorbol myristate acetate, PMA). The mechanisms proposed for CTP that are relevant for the tumor types associated with immunosuppression, such as nonmelanoma skin tumors and lymphomas, are listed in Table 27.3. The table is limited to mechanisms of promotion and does not include tumor initiation mechanisms, namely those that directly or indirectly damage DNA (e.g., free radicals mediated by metabolism of ethanol) [16] or are mechanisms of neovasularization (e.g., angiogenesis in response to UV-A and B) [17], The table also excludes mechanisms of CTP that have only been studied in the context of irrelevant tumors, such as TCDD in hepatocarcinogenesis [18],... 

Human neutrophils were exposed to the tumor promoter phorbol myristate acetate (PMA, 100 nM). After a steady state of metabolism had been achieved, the cell suspension was homogenized and, after centrifugation, membrane and supernatant fractions were collected. Membrane and supernatant fractions were also prepared from cells that had not been exposed to PMA. Samples of both homogenates (i.e., prior to centrifugation) were also collected. The fractions were then assayed for the presence of protein kinase C. After the protein kinase C assay was performed the following data were obtained ... 

In normal healthy individuals, the spontaneous reduction of NBT dye by neutrophils is very low (less than 10% of the cells are positive). A low basal NBT response is an important negative control during the performance of any NBT test, as it monitors the non-stimulatory nature of the test reagents and procedure. Stimulated NBT tests are carried out as a positive control. By deliberately stimulating cells with specific stimulating agents, such as phorbol myristate acetate (PMA) one can activate cells from normal individuals to reduce NBT in a dose-responsive manner. 

Phorbol myristate acetate (PMA) ibrinogen gamma chain dodecapeptide (H12)... 

Buddlejasaponin FV and sandrosaponin I present a potent in vivo antiinflamatory effect on mouse ear edema induced by phorbol myristate acetate (PMA). The effects of these compounds on swelling and other inflamatory parameters are described. In screening... 

Recently, we have reported the in vivo and in vitro anti-inflammatory activity of two saikosaponins isolated from B. rigidum, budlejasaponin IV and sandrosaponin I, in order to establish the possible real value of these kinds of compounds as anti-inflammatory agents [44]. We showed that saikosaponins inhibited the mouse ear edema induced by topical administration of phorbol myristate acetate (PMA). Saikosaponins, at a dose of 1 mg/ear, significantly inhibited swelling and were as potent as the reference drug indomethacin at 3 mg/ear. These findings were supported by vascular permeability analysis [Table 10 and Fig. (4)]. 

Control of cytokine release by CD8 T cells shares some features with CD4 T cells, although there is no direct correlation between CD8 subsets and ThI and Th2 cell subsets. Mouse CD8 spleen cells cultured with IL-2, IL-4 and anti-CD3 antibodies produce large amounts of IL-4 (Seder et al., 1992). Rat CD8" T cells cultured with Con A, IL-2, IL-4 and anti-IFN7 generate increased amounts of IL-4 and IU5 mRNA when restimulated with phorbol myristate acetate (PMA) and ionomycin (Noble, MacAry and Kemeny, 1995). However, in contrast to Th2 cells, most alloreac-... 

The scavenging effect of berbamine on active oxygen radicals was studied via a spintrapping technique and a chemiluminescence (CL) method in phorbol myristate acetate (PMA) stimulated polymorphonuclear leukocytes (PMN) and in four-cell superoxide (02+) or hydroxyl radical (OH ) generating systems. The alkaloid (0.1-0.3 mM) effectively reduced active oxygen radicals in PMA-stimulated PMN, but had no obvious effect on oxygen consumption during the respiratory burst of PMN (as measured with spin probe oxymetry). In addition, berbamine (0.3 mM) inhibited the CL response of PMA-stimulated PMN, and quenched 02 in the xanthine/xanthine oxidase and irradiation riboflavin systems, as well as OH in the Fenton... 

Yet, whether l,25(OH)2D3 is an inducer of Th2 T cell responses remains controversial because l,25(OH)2D3 may also suppress IL-4 if present during the process of in vitro polarization of naive CD62L+ CD4+ T cells [130]. This may explain why 1,25 (OH)2D3 does not exclusively inhibit Thl-mediated diseases but also has beneficial effects in a Th2-dependent allergic asthma model (our own unpublished data). Moreover, l,25(OH)2D3 and its analog EB1089 are potent suppressors of IgE secretion from B cells activated with anti-CD40 and IL-4 [39]. Also, Thl, Th2 as well as ThO T cells are clearly susceptible to l,25(OH)2D3, since it inhibits phorbol myristate acetate (PMA)/ionomycin-induced proliferation of all three types of purified CD4+ T cells [38],... 

Alkaloids isolated from an unidentified colonial zoanthid have also exhibited interesting biological activities. Zoanthamine (5), zoanthenamine (6), zoanthamide (7), and 28-deoxyzoanthenamine (8) possess inhibitory activity in the phorbol myristate acetate (PMA)-induced mouse ear inflammation assay, as well as analgesic activity (22). Zoanthamine (5) also exhibited strong nematicidal activity against the root-knot nematode (Meloidogyne javanica) and antibacterial activity (41). 

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