Recombinant interleukin-4 enhances the chemiluminescent oxidative burst of murine peritoneal macrophages.

We evaluated the effects of murine recombinant interleukin-4 (rIL-4) on murine peritoneal macrophages. We showed a marked, dose-dependent stimulation of respiratory oxidative burst by IL-4 in peptone-elicited murine peritoneal macrophages. This effect was abolished by a neutralizing monoclonal antibody (mAb) to rIL-4 confirming that the enhanced chemiluminescence was due to IL-4. In contrast, rIL-4 depressed the respiratory oxidative burst of a transformed murine macrophage cell line, J774, in a dose-dependent mAb-reversible manner.

The effects of nerve growth factor and ganglioside GM1 on the anti-proliferative activity of cocaine in PC12 cells.

The anti-proliferative activity of cocaine was determined in PC12 phenochromocytoma cells. The effects of nerve growth factor (NGF) and ganglioside GM1 (GM1) on the toxicity of this stimulant of abuse was examined over a period of 72 h. Cocaine (40 microM-320 microM) exhibited a dose-dependent inhibition of cellular proliferation as determined by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) reduction. While NGF (100 ng/ml) and GM1 (100 microM) alone partially reversed the cocaine-induced inhibition of proliferation, the combination of NGF and GM1 afforded additional protection that was greater than that of either agent individually.

Lucigenin chemiluminescence as a probe for measuring reactive oxygen species production in Escherichia coli.

Addition of oxygen to whole cells of Escherichia coli suspended in the presence of the chemiluminescent probe bis-N-methylacridinium nitrate (lucigenin) resulted in a light emission increase of 200% of control. Addition of air to cells showed a chemiluminescent response far less than the response to oxygen. The redox cycling agents paraquat and menadione, which are known to increase intracellular production of O2- and H2O2, were also found to cause a measurable increase in lucigenin chemiluminescence in E. coli cells when added at concentrations of 1 and 0.1 mM, respectively. The oxygen-induced chemiluminescent response was not suppressed by extracellularly added superoxide dismutase or catalase. Further, the lucigenin-dependent chemiluminescent response of aerobically grown E. coli to oxygen was significantly greater than that of cells grown anaerobically. Heat-killed cells showed no increase in chemiluminescence on the addition of either oxygen, paraquat, or menadione. These results show that lucigenin may be used as a chemiluminescent probe to demonstrate continuous intracellular production of reactive oxygen metabolites in E. coli.

Phagocytic cell chemiluminescence using different zymosan preparations.

This study compared the effectiveness of opsonized and unopsonized zymosan prepared in our laboratories with a commercially available opsonized preparation used for induction of luminol-dependent oxidative burst in phagocytic cells. The production of chemiluminescence (CL) by human whole blood, isolated human neutrophils, normal BALB c mouse splenocytes, and an immortal BALB c mouse macrophage cell line (J774A.1) was tested in an automated luminometer. Recombinant murine or human interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS) were used as priming agents in some of the experiments. With human leukocytes and normal mouse spleen cells the laboratory-prepared zymosans (regardless of opsonization) induced equal or significantly greater CL than did the commercially prepared zymosan. In addition, greatly increased CL was evident with IFN-gamma- and LPS-primed neutrophils tested with our zymosans compared with the commercial preparation. These results suggest that effective zymosans capable of inducing strong, reproducible CL responses from several different phagocytic cell populations can be readily made in the laboratory.

Modeling drug-melanin interaction with theoretical linear solvation energy relationships.

The affinity of drugs and other xenobiotic agents for melanin is a well-known phenomenon, often occurring with serious physiological consequences. For example, the interaction of anti-psychotic drugs with neuromelanin may play a pivotal role in the induction of extrapyramidal movement disorders associated with the chronic administration of phenothiazine and other neuroleptic agents. Little, however, is known about the complete nature of melanin-drug binding and the impact of these interactions on the physico-chemical properties of melanin. Data, such as binding affinities, can be analyzed using recently developed computational methods that combine mathematical models of chemical structure with statistical analysis. In particular, theoretical linear solvation energy relationships provide a convenient model for understanding and predicting biological, chemical, and physical properties. By using this modeling technique, drug-melanin binding of a set of 16 compounds has been analyzed with correlation analysis and a set of theoretical molecular parameters in order to better understand and characterize drug-melanin interactions. The resulting correlation equation supports a charge transfer model for drug-melanin complex formation and can also be used to estimate binding constants for related compounds.

Modulation of chemiluminescence in a murine macrophage cell line by neuroendocrine hormones.

This study determined the effects of neuropeptides and neuroendocrine hormones at the cellular level of the immune response using a murine macrophage cell line, J774, which exhibits a chemiluminescent oxidative burst upon acute stimulation with zymosan. We report that the zymosan-triggered oxidative burst of J774 cells can be modulated by the opioid peptides beta-endorphin (beta-END) and dynorphin A (DYN) in a naloxone-reversible fashion. Norepinephrine (NE) also modulated chemiluminescence (CL) emission of J774 cells, with dose-dependent suppression of CL dependent upon co-incubation with gamma-interferon (gamma-INF). Without gamma-INF co-incubation, NE shared with the opioid peptides beta-END and DYN the ability to modulate oxidative burst, producing an inverted-U dose response. These data indicate that J774 cells may be useful for explaining some mechanisms through which the neuroendocrine system interacts with the immune system.

Effects of the interaction between ferric iron and L-dopa melanin on T1 and T2 relaxation times determined by magnetic resonance imaging.

T1 and T2 relaxation times of agar phantoms containing L-dopa melanin and Fe3+ were measured under MRI conditions. Fe3+ shortened T1 and T2 relaxation times. Melanin influenced relaxation times only in the presence of Fe3+; thus, contrast in MR images of the basal ganglia may depend upon levels of both paramagnetic iron and neuromelanin.