The secretion of tumour necrosis factor-alpha (TNFalpha), interleukin-1alpha (IL-alpha) and interleukin-6 (IL-6) by a human astrocytoma cell fine was studied 1 h, 3 h, 6 h and 24 h after infection with tachyzoites from three Toxoplasma gondii strains (virulent, RH; cystogentc, 76K and Prugniaud strains). The astrocytoma cell fine constitutively secreted TNFalpha and IL-6, but no IL-1alpha. A po...

Phorbol esters, which activate protein kinase C, modulate vasoconstrictor-induced tension in vascular smooth muscle. We examined the effects of phorbol esters (phorbol 12,13-dibutyrate [PDBu] and 12-O-tetradecanoylphorbol 13-acetate [TPA]) on receptor agonist (serotonin [5-HT] and arginine vasopressin [AVP])-, high K(+)-, and caffeine-induced contractions in rings of rat aorta and a small (seco...

We have used a permeabilized cell assay and a synthetic peptide substrate (KRTLRR) to specifically monitor the activity of protein kinase C in PC12 cells preincubated with nerve growth factor (NGF), epidermal growth factor (EGF), or phorbol esters. Pretreatment of PC12 cells with 1 PM 12-0-tetradecanoylphorbo1 13-acetate or 1 I.~M phorbol dibutyrate stimulated the rate of KRTLRR peptide phospho...

The members of the chimaerin family of Rac-GTPase-activating proteins possess a single C1 domain with high homology to those present in protein kinase C (PKC) isozymes. This domain in PKCs is involved in phorbol ester and diacylglycerol (DAG) binding. We previously have demonstrated that one of the chimaerin isoforms, beta2-chimaerin, binds phorbol esters with high affinity. In this study we an...

We have studied the expression of mRNA encoding adenosine deaminase (ADA; EC 3.5.4.4), purine nucleoside phosphorylase (PNP; EC 2.4.2.1), and terminal deoxynucleotidyltransferase (TdT; EC 2.7.7.31) in different leukemic cell lines of Band T-cell lineage. Incubation of leukemic cells in the presence of the phorbol esters, 12-O-tetradecanoylphorbol-13-acetate or phorbol 12,13-dibutyrate, resulted...

The conversion of determined adipoblasts to fully differentiated adipocytes requires appropriate environmental conditions. A strict dependence on cell confluence and a facilitation by glucocorticoid hormones have previously been described. We have found that agents that are capable of activating protein kinase C, such as basic fibroblast growth factor and phorbol esters, inhibit the differentia...

A number of characteristics of phorbol ester-mediated mouse skin tumor promotion indicate that cell selection is the underlying biological process. Studies in vivo and in cultured mouse epidermal cells suggest that selection is based on heterogeneous responses of subpopulations of basal cells which can be induced to proliferate or differentiate in response to promoter exposure. Retinoids are ef...

PURPOSE Phorbol esters have been shown to have a profound influence on cellular activity in many cell types. The purpose of this study was to examine the influence of phorbol esters on the function and structure of corneal endothelial cells. METHODS Corneas were placed under a specular microscope, and the endothelium was superfused with glutathione bicarbonate Ringer's solution (GBR); with GB...

Phorbol esters are potent inducers of macrophage-like differentiation in the HL-60 promyelocytic leukemia cell line. The sequence of events by which they bring about this transition is poorly understood. However, it is known that phorbol esters bind to the surface membrane of HL-60 cells and to various other cells as well. Our studies were directed toward determining the biologic importance of ...