Nitric oxide (NO) produced by inducible NO synthase (iNOS, NOS-2) is an important component of the macrophage-mediated immune defense toward numerous pathogens. Murine macrophages produce NO after cytokine activation, whereas, under similar conditions, human macrophages produce low levels or no NO at all. Although human macrophages can express iNOS mRNA and protein on activation, whether they p...

In a previous study, we demonstrated that bufalin, which is an active principle of Chinese medicine, chan'su, caused apoptosis in human leukemia U937 cells by anomalous activation of mitogen-activated protein kinase (MAPK) via the signaling pathway of Ras, Raf-1, and MAPK kinase-1. Here, we report the effect of overexpression of bcl-2 in U937 cells on the signaling pathway of apoptosis that is ...

In a previous study, we demonstrated that bufalin, which is an active principle of Chinese medicine, chan'su, caused apoptosis in human leu kemla U937 cells by anomalous activation of mitogen-activated protein kinase (MAPK) via the signaling pathway of Ras, Raf-1, and MAPK kinase-1. Here, we report the effect ofoverexpression ofbcl-2 in U937 cells on the signaling pathway of apoptosis that Is i...

Pipoxolan HCl (5,5-diphenyl-2-(2'-piperidino-ethyl)-1,3-dioxolane-4-one hydrochloride) is a compound containing a dioxolan moiety that was reported to induce apoptosis in cancer cells. In this study, we investigated the anti-leukemia effects of pipoxolan on U937 leukemia cells both in vivo and in vitro. Cell viability, reactive oxygen species (ROS) production, mitochondrial membrane potential, ...

The human immunodeficiency virus (HIV) Vpr protein plays a critical role in AIDS pathogenesis, especially by allowing viral replication within nondividing cells such as mononuclear phagocytes. Most of the data obtained so far have been in experiments with endogenous Vpr protein; therefore the effects of extracellular Vpr protein remain largely unknown. We used synthetic Vpr protein to activate ...

Aleutian mink disease parvovirus (ADV) infects macrophages in adult mink. The virulent ADV-Utah I strain, but not the cell culture-adapted ADV-G strain, infects mink peritoneal macrophage cultures and the human macrophage cell line U937 in vitro. However, preincubation of ADV-G with ADV-infected mink serum enhanced its infectivity for U937 cells. the enhancing activity was present in the protei...

Microglia- and macrophage-induced neuronal death may underlie a number of neurodegenerative diseases. The effects of factors secreted by monocytic cells were studied on glutamatergic synaptic transmission between cultured rat hippocampal neurons. Conditioned media from differentiated human U937 cells was collected after 24 h and applied to neurons (0.5%-30% dilution). Unactivated U937 cells spo...

Cdk9 is the catalytic subunit of TAK (cyclinT1/P-TEFb), a cellular protein kinase that mediates human immunodeficiency virus type 1 (HIV-1) Tat transcriptional activation function. To examine Cdk9 function in cells relevant to HIV-1 infection, we used a murine leukemia virus retrovirus vector to transduce and overexpress the cDNA of a dominant negative mutant Cdk9 protein (Cdk9-dn) in Jurkat T ...

beta-glucan receptors, with ligand specificity for yeast and fungal carbohydrate polymers, have been studied as phagocytic receptors of human monocytes. To characterize their structure, binding studies were carried out with human U937 cells and a rabbit IgG anti-Id that recognizes epitopes on monocyte beta-glucan receptors. Unstimulated U937 cells specifically bound large amounts of the anti-Id...

It has previously been reported that murine macrophages can respond chemotactically and mitogenically to the serine proteinase thrombin. There is a similar response in these macrophages to catalytically inactivated thrombin or to peptide fragments of the thrombin B-chain [Bar-Shavit, Kahn, Mann and Wilner (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 976-980]. However, the existence of a non-proteol...