Regulation of macrophage inflammatory protein-1 alpha expression and function by endogenous interleukin-10 in a model of acute inflammation.

In this study we have determined the role of endogenous interleukin (IL)-10 on leucocyte recruitment and production of the CC chemokine macrophage inflammatory protein-1alpha (MIP-1alpha) in a murine model of acute inflammation. Intraperitoneal injection of zymosan produced a dose-dependent cellular infiltration which was concomitant with MIP-1alpha release in the lavage fluids. Release of this chemokine had a functional role since treatment of mice with a specific anti-MIP-1alpha antibody reduced both neutrophil and monocyte accumulation into the peritoneal cavity.

Role of resident peritoneal macrophages and mast cells in chemokine production and neutrophil migration in acute inflammation: evidence for an inhibitory loop involving endogenous IL-10.

The roles played by resident macrophages (Mphi) and mast cells (MCs) in polymorphonuclear leukocyte (PMN) accumulation and chemokine production within the mouse peritoneal cavity in response to administration of zymosan (0.2 and 1 mg), LPS (1 mg/kg), and thioglycolate (0.5 ml of a 3% suspension) were investigated.

Role of inducible nitric oxide synthase in the regulation of neutrophil migration in zymosan-induced inflammation.

In the present study, by comparing the responses in wild-type mice and mice lacking the inducible (or type 2) nitric oxide synthase (iNOS), we investigated the role played by iNOS in the regulation of polymorphonuclear granulocyte (PMN) accumulation and chemokine production in the mouse peritoneal cavity in response to administration of zymosan (0.2 mg). Zymosan injection induced the production of nitric oxide, and triggered a time-dependent PMN immigration into the peritoneal cavity.

Crucial role of apopain in the peroxynitrite-induced apoptotic DNA fragmentation.

Peroxynitrite, a cytotoxic oxidant formed in the reaction of superoxide and nitric oxide is known to cause programmed cell death. However, the mechanisms of peroxynitrite-induced apoptosis are poorly defined. The present study was designed to characterize the molecular mechanisms by which peroxynitrite induces apoptosis in HL-60 cells, with special emphasis on the role of caspases.

Oxidation, tyrosine nitration and cytostasis induction in the absence of inducible nitric oxide synthase.

In the present study, we evaluated the impact of the lack of the gene for inducible nitric oxide synthase (iNOS) on oxidation, tyrosine nitration and cytotoxicity reactions triggered by immunostimulation. In mice injected with E. coli endotoxin (bacterial lipopolysaccharide, LPS, 50 mg/kg i.

Interaction of the alpha-2 adrenergic- and opioid receptor with the cGMP system in the mouse cerebellum.

The alpha-2 adrenergic agonist dexmedetomidine (Dex), 3-300 microg/kg, i.p., decreased cerebellar cGMP in a dose-dependent manner.

Suppression of macrophage inflammatory protein (MIP)-1alpha production and collagen-induced arthritis by adenosine receptor agonists.

1. Ligands of the various adenosine receptor subtypes modulate the production of pro-and anti-inflammatory cytokines. Here we evaluated the effect of adenosine and various ligands of the adenosine receptor subtypes (A1, A2, A3) on the chemokine macrophage inflammatory protein (MIP) 1alpha production in immunostimulated RAW macrophages in vitro.

NADPH diaphorase-positive dendritic profiles in rat thymus are discrete from autofluorescent cells, immunoreactive for inducible nitric oxide synthase, and show strain-specific abundance differences.

Predisposition to autoimmune disorder in Lewis rats has been associated with abnormal hypothalamic regulation of circulating steroids, leading to inadequate suppression of T helper 1 (Th1) cell-mediated inflammatory reactions. In addition, autoimmune syndromes can be triggered within formerly resistant animals, following damage to the negative selection process of the thymus. A contribution to the autoimmune-susceptible phenotype may therefore derive from the status of thymic tolerance.

Peroxynitrite-induced thymocyte apoptosis: the role of caspases and poly (ADP-ribose) synthetase (PARS) activation.

The mechanisms by which immature thymocyte apoptosis is induced during negative selection are poorly defined. Reports demonstrated that cross-linking of T-cell receptor leads to stromal cell activation, expression of inducible nitric oxide synthase (iNOS) and, subsequently, to thymocyte apoptosis. Therefore we examined, whether NO directly or indirectly, through peroxynitrite formation, causes thymocyte apoptosis.

Poly(ADP-ribose) synthetase activation mediates mitochondrial injury during oxidant-induced cell death.

Reactive oxidant species are important mediators of tissue injury in shock, inflammation, and reperfusion injury. The actions of a number of these oxidants (e.g.

NADPH diaphorase histochemistry detects inducible nitric oxide synthetase activity in the thymus of naive and staphylococcal enterotoxin B-stimulated mice.

Here we examined the changes in NADPH diaphorase (NADPHd) and inducible nitric oxide synthetase (iNOS) positivity in the medulla of the mouse thymus in response to treatment with the superantigen, Staphylococcal enterotoxin B (SEB). A few NADPHd+ and iNOS+ cells scattered in the medulla were detected in the thymi of naive mice. SEB induced the appearance of a large number of NADPHd+- and iNOS-immunoreactive cells in the thymic medulla.

Melatonin inhibits expression of the inducible isoform of nitric oxide synthase in murine macrophages: role of inhibition of NFkappaB activation.

The role of melatonin as an immunomodulator is well established. Recent reports showed that melatonin exerts protective effects in septic and hemorrhagic shock and in inflammation. The expression of the inducible isoform of nitric oxide synthase (iNOS) makes an important contribution to the pathophysiology of shock and inflammation.

The crucial role of IL-10 in the suppression of the immunological response in mice exposed to staphylococcal enterotoxin B.

Staphylococcal enterotoxin B (SEB), a bacterial superantigen, activates the immune system resulting in a burst of pro- and anti-inflammatory cytokines. A central anti-inflammatory mediator in this process is IL-10. Using IL-10-deficient C57BL/6 (IL-10 KO) mice, we studied the role of endogenous IL-10 in the regulation of the immune response to SEB.

Protection against peroxynitrite-induced fibroblast injury and arthritis development by inhibition of poly(ADP-ribose) synthase.

Peroxynitrite, a cytotoxic oxidant formed from nitric oxide (NO) and superoxide, induces DNA strand breakage, which activates the nuclear enzyme poly(ADP-ribose) synthase (PARS; EC 2.4.2.

Effect of disopyramide on potassium currents in rabbit ventricular myocytes.

The effects of disopyramide (1-30 microM) on the 4-aminopyridine sensitive transient outward current (I(to)), on the rapid component of the delayed rectifier potassium current (I(Kr)) and on the inward rectifier potassium current (I(kl)) were studied in single rabbit ventricular myocytes at 35 degrees C by applying the whole-cell configuration of the patch clamp technique. Disopyramide significantly decreased the amplitude of I(to) (from 1510 +/- 122 pA at control to 1015 +/- 21 pA after 30 microM disopyramide at +50 mV; n = 5). This effect was not voltage- or use-dependent.

Alpha-2 adrenoceptor agonists decrease cyclic guanosine 3',5'-monophosphate in the mouse brain.

Background: In the central nervous system neurotransmitters, drugs or conditions that excite increase cyclic guanosine 3',5'-monophosphate (cGMP), an effect mediated by the neuromodulator nitric oxide, whereas those that sedate decrease cGMP. Volatile anesthetics were shown to decrease cerebellar cGMP, an effect that correlates with their anesthetic and anticonvulsant effect. Because alpha-2 adrenoceptor agonists have anesthetic properties, the role of the nitric oxide-cGMP pathway in the action of the alpha-2 adrenoceptor agonists clonidine and dexmedetomidine was investigated.

Determination of cocaine, norcocaine, benzoylecgonine and ecgonine methyl ester in rat plasma by high-performance liquid chromatography with ultraviolet detection.

An isocratic high-performance liquid chromatographic method with ultraviolet detection at 235 nm is described for the determination of cocaine and its metabolites benzoylecgonine, norcocaine and ecgonine methyl ester in rat plasma, collected during toxicity studies. Following simultaneous solid-phase extraction of all analytes and the internal standard tropacocaine, cocaine, benzoylecgonine and norcocaine were separated on a C18 column. Ecgonine methyl ester and cocaine were separated on coupled cyanopropyl and silica columns, following derivatization of ecgonine methyl ester to p-fluorococaine.

Strain differences in the cytotoxic activity and TNF production of murine macrophages stimulated by lentinan.

The effect of lentinan, a glucan type immunomodulatory polysaccharide was studied on the antitumor cytotoxicity and on the TNF secretion of peritoneal macrophages in inbred H-2 congeneic mouse strains under in vivo and in vitro conditions. The cytotoxic activity and TNF secretion of murine macrophages was found to be elevated by lentinan in vitro and in vivo conditions. The effectiveness of lentinan to induce cytotoxicity and TNF secretion was highly influenced by the genotype of the host.

Cardiac electrophysiological effects of levosimendan, a new calcium sensitizer.

1. The conventional microelectrode and the patch-clamp techniques were used to study the electrophysiological effects of levosimendan, a new calcium-sensitizing cardiotonic drug, in cardiac ventricular muscle. 2.

Comparison of the chronic and acute effects of amiodarone on the calcium and potassium currents in rabbit isolated cardiac myocytes.

1. The acute and chronic effects of amiodarone were studied on the transmembrane ionic currents in rabbit single ventricular myocytes at 35 degrees C by applying the whole-cell configuration of the patch-clamp technique. 2.

The cellular electrophysiological effects of tedisamil in human atrial and ventricular fibers.

The cellular electrophysiological effects of 1 microM tedisamil (KC 8857) were studied in human atrial and ventricular fibers. Conventional microelectrode technique was applied to record the transmembrane action potentials at stimulation frequency of 100 per min and 37 degrees C. Tedisamil lengthened action potential duration (APD) more in atrial than in ventricular muscle fibers; prolongation of APD90 was 28.

Comparison of the effects of restacorin and flecainide on various cardiac transmembrane potassium currents.

The effect of restacorin (5 microM) and flecainide (5 microM) on the transmembrane ionic currents was compared in dog and rabbit ventricular muscle by applying the conventional microelectrode and patch-clamp techniques. Neither restacorin nor flecainide influenced significantly the ATP-sensitive and inward rectifier potassium currents. Flecainide moderately decreased the amplitude of the transient outward current while restacorin did not change this current.

Lethal toxicity from equimolar infusions of cocaine and cocaine metabolites in conscious and anesthetized rats.

We compared the lethal toxicity of cocaine with that of three of its metabolites to determine the contribution of these metabolites to the lethal potential from cocaine infusion. Equimolar quantities of cocaine, norcocaine, benzoylecgonine, and ecgonine methyl ester were infused in conscious rats to determine onset of convulsions and respiratory arrest. In addition, the convulsive and respiratory toxicity for cocaine and norcocaine were evaluated in anesthetized rats and their circulatory toxicity in anesthetized and ventilated rats.