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Biomedical subjects

P Ghezzi

Publications and source records attributed to P Ghezzi.

At least 127 records · Page 7Linked to original sources
PubMed1990

Interleukin 1-induced augmentation of experimental metastases from a human melanoma in nude mice.

This study has examined the effect of the cytokine interleukin 1 (IL-1) on metastasis formation by the human melanoma A375M in nude mice. We have found that human recombinant IL-1 beta (a single injection greater than 0.01 micrograms per mouse i.v. given before tumor cells) induced an augmentation of experimental lung metastases from the A375M tumor cells in nude mice. This effect was rapidly induced and reversible within 24 h after IL-1 injection. A similar effect was induced by human recombinant IL-1 alpha and human recombinant tumor necrosis factor, but not by human recombinant interleukin 6. 5-[125I]odo-2'-deoxyuridine-radiolabeled A375M tumor cells injected i.v. remained at a higher level in the lungs of nude mice receiving IL-1 than in control mice. In addition, IL-1 injected 1 h, but not 24 h, after tumor cells enhanced lung colonization as well, thus suggesting an effect of IL-1 on the vascular transit of tumor cells. These findings may explain the observation of enhanced secondary localization of tumor cells at inflammatory sites and suggest that modulation of secondary spread should be carefully considered when assessing the ability of this cytokine to complement cytoreductive therapies.

Animals↗
PubMed1990

Intracerebroventricular injection of interleukin 1 induces high circulating levels of interleukin 6.

IL-1 is known to have a central role in the induction of acute-phase response, and some of its activities (including induction of some acute-phase proteins) were reported to be mediated by an induction of IL-6. Administration to rats of 200 ng of human rIL-1 by intracerebroventricular injection resulted in a more marked induction of circulating IL-6 than the same dose of IL-1 administered systemically (intravenously or intraperitoneally). Induction of serum IL-6 by centrally administered IL-1 was also observed in hypophysectomized or adrenalectomized rats, suggesting that activation of the hypothalamus-pituitary-adrenal axis is not essential for this effect of IL-1. IL-6 induction was also observed after pretreatment with indomethacin, indicating that the effect was dissociated from the pyrogenic activity of IL-1. Induction of IL-6 by a central action could represent a novel pathway in IL-1-induced acute-phase response.

Adrenalectomy↗
PubMed1990

IL-1 induces IL-1. IV. IFN-gamma suppresses IL-1 but not lipopolysaccharide-induced transcription of IL-1.

IL-1 induces its own gene expression in human PBMC, in cultured smooth muscle and in endothelial cells. IL-1-induced IL-1 may be part of a self-amplification or an autocrine growth factor in a variety of responses, and thus the endogenous regulation of IL-1 production likely contributes to the outcome of immunologic or inflammatory responses. In the present study, IFN-gamma consistently increased LPS-induced IL-1, but reduced the total amount of IL-1-induced IL-1 from PBMC. This reduction was observed in populations of adherent cells and cells selected with anti-Leu M3 antibody. On a molar basis, IFN-gamma and IFN-alpha 2 were equally effective in reducing IL-1-induced IL-1 synthesis. In PBMC of 24 human subjects, IFN-gamma also reduced PMA-induced IL-1 synthesis (67% decrease, p less than 0.001). The augmentation of LPS-stimulated IL-1 by IFN-gamma was observed only when added at the same time as LPS, but IFN-gamma could be added 6 h after stimulation with IL-1 and still suppress IL-1 production. LPS-induced mRNA for IL-1 beta was modestly enhanced by IFN-gamma whereas mRNA levels for TNF were markedly increased. In contrast, IFN-gamma suppressed mRNA accumulation for IL-beta after stimulation with IL-1 alpha by 60 to 95%. The addition of IFN-gamma 30 min before stimulation of PBMC with IL-1 suppressed IL-1 beta mRNA for up to 30 h. The half-life of IL-1 beta mRNA of approximately 2 h was not influenced by IFN-gamma. Thus, IFN-gamma reduces IL-1-induced IL-1 synthesis by suppressing IL-1-induced transcription, whereas the same concentrations of IFN-gamma augment LPS-induced IL-1 production by increasing transcription.

Cell Adhesion↗
PubMed1990

Ambroxol inhibits interleukin 1 and tumor necrosis factor production in human mononuclear cells.

We have studied the effect of Ambroxol on the production of Interleukin-1 (IL-1) and Tumor Necrosis Factor (TNF) in human mononuclear cells (MNC). For this purpose MNC were cultured for 24 h in the presence of endotoxin and different doses of Ambroxol. The results indicate that Ambroxol markedly inhibited IL-1 and TNF production at doses of 10-100 microgram ml, without any apparent toxicity.

Ambroxol↗
PubMed1990

Purification and characterization of mouse liver xanthine oxidase.

Xanthine oxidase (EC 1.1.3.22) is purified to homogeneity from mouse liver after induction with bacterial lipopolysaccharide. The enzyme has an apparent molecular weight of 300,000 in its native state and it is suggested to be constituted of two identical subunits of Mr 150,000 each. The isoelectric point is 6.7 and the apparent Km value for xanthine is 3.4 microM. The amino acid composition of mouse xanthine oxidase is quite similar to that of Drosophila xanthine dehydrogenase.

Amino Acids↗
PubMed1990

Interleukin-1 induces tumor necrosis factor (TNF) in human peripheral blood mononuclear cells in vitro and a circulating TNF-like activity in rabbits.

Recombinant human interleukin-1 (IL-1), injected into rabbits, induces the synthesis of endogenous IL-1. Also, IL-1 induces its own gene expression and synthesis in human peripheral blood mononuclear cells (PBMC). In this study, tumor necrosis factor-alpha (TNF-alpha) production by PBMC of 40 individuals stimulated with IL-1 alpha or IL-1 beta was determined by specific radioimmunoassay (RIA). After 3 h of PBMC incubation with IL-1, TNF-alpha mRNA was detected. IL-1 alpha stimulated both IL-1 beta and TNF-alpha, but there was no correlation in the amount of TNF-alpha or IL-1 beta synthesized in the PBMC of 29 individuals. IL-1-stimulated adherent cells produced approximately 50% more TNF-alpha than did unfractionated PBMC. Coincubation with interferon-gamma (IFN-gamma) did not change the amount of IL-1-induced TNF-alpha, whereas in the same culture IFN-gamma inhibited (greater than 70%) IL-1-induced IL-1 production. Endogenous pyrogen and TNF-like activity were detected in the sera of rabbits 3.5 h after injection of either IL-1 alpha or -1 beta. These studies demonstrate that IL-1 induced TNF-alpha production in vivo and in vitro.

Animals↗
PubMed1990

Interleukin 1, a prototypic pleiotropic lymphokine.

Interleukin 1 (IL-1) is an endogenous mediator produced by monocytes/macrophages, endothelial cells and other cell types. It was originally identified as the main endogenous pyrogen. It was later found that IL-1 was identical to other factors that had been defined leukocytic endogenous mediator, lymphocyte activating factor. It is now clear that IL-1 has two main aspects. On one side it is an immunostimulatory molecule and on the other side is a mediator of shock and inflammation. As an immunostimulating molecule, IL-1 is a potential immuno-modulating drug, while with respect to its proinflammatory action it might be important to identify antagonists or inhibitors that could be useful in the therapy of chronic inflammatory diseases.

Adjuvants, Immunologic↗
PubMed1989

Protective effect of chlorpromazine against the lethality of interleukin 1 in adrenalectomized or actinomycin D-sensitized mice.

Interleukin 1 (IL-1) and Tumor Necrosis Factor (TNF) are thought to play a key role in septic shock and inflammation. We have tested the effect of dexamethasone (DEX) and chlorpromazine (CPZ) on the lethal effect of IL-1, TNF and endotoxin. Two different experimental models were used to sensitize mice to the lethal effect of IL-1: adrenalectomy and pretreatment with actinomycin D. CPZ (4 mg/kg) was found to protect mice against IL-1 and endotoxin toxicity in all cases, while DEX had a protective effect only in adrenalectomized mice. In contrast to its protective effect against IL-1 and endotoxin, CPZ did not protect mice against TNF. These findings might be useful in the analysis of the differences in the actions of IL-1 and TNF in vivo, and in the development of new drugs preventing their toxicity.

Adrenalectomy↗
PubMed1989

Dexamethasone modulation of in vivo effects of endotoxin, tumor necrosis factor, and interleukin-1 on liver cytochrome P-450, plasma fibrinogen, and serum iron.

Treatment of mice with endotoxin (lipopolysaccharide, LPS) and the two LPS-induced monokines, tumor necrosis factor (TNF) and interleukin-1 (IL-1), caused a depression of liver cytochrome P-450 and related drug-metabolizing enzymes, as well as other acute-phase changes including increase in plasma fibrinogen levels and hypoferremia. However, only IL-1, not TNF or LPS, depressed cytochrome P-450 in cultured hepatocytes, suggesting that the effect of TNF in vivo might be mediated by a second mediator. TNF- or LPS-stimulated monocytes released a factor capable of depressing cytochrome P-450 in cultured hepatocytes. This factor was inhibited by anti-IL-1 antiserum, and its synthesis, like that of IL-1, was inhibited by dexamethasone (DEX). Pretreatment of mice with DEX protected against the depression of liver cytochrome P-450 by LPS or TNF but not by IL-1, suggesting that IL-1 directly depresses cytochrome P-450 and that DEX acts by inhibiting IL-1 synthesis in vivo induced by LPS or TNF. However, DEX did not inhibit two other effects of LPS and TNF in vivo: increase of plasma fibrinogen levels and decrease of plasma iron, suggesting that these might not be mediated by IL-1. Therefore, the effect of DEX in vivo, although supporting the hypothesis that depression of liver cytochrome P-450 by LPS and TNF is mediated by IL-1, indicates the existence of IL-1-independent pathways in the acute-phase response.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1989

In vitro inhibition of human polymorphonuclear cell function by cloricromene.

Cloricromene, a coumarin derivative with antiaggregating and vasodilating properties, was tested in vitro on polymorphonuclear cell (PMN) adhesion to the endothelium, superoxide anion generation and chemotaxis. PMN adhesion was measured using cultured human umbilical vein endothelial cells (EC) either untreated or previously activated with interleukin-1 (IL-1). Cloricromene (5-50 microM) induced dose-related inhibition of PMN adhesion to untreated and IL-1 treated EC. Cloricromene also inhibited PMN superoxide generation induced by the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or by N-formyl-methionyl-leucyl-phenylalanine (FMLP). PMN and monocyte chemotaxis was evaluated by a modification of the Boyden chamber technique. Cloricromene inhibited both types of cell motility induced by FMLP in a concentration-dependent fashion. The major cloricromene metabolite (cloricromene acid) had no effect on any of the biological parameters studied up to a concentration of 500 microM. HPLC measurement showed that cloricromene accumulated in PMN within a few minutes and levels of the drug were still high after 60 min. In contrast its acid metabolite was not taken up in a significant amount during incubation periods up to 60 min. We conclude that cloricromene inhibits a series of PMN activities in vitro. This effect might be of pharmacological interest in view of the role of PMN activation in different pathophysiological conditions.

Cell Adhesion↗
PubMed1989

Protection against pulmonary oxygen toxicity by interleukin-1 and tumor necrosis factor: role of antioxidant enzymes and effect of cyclooxygenase inhibitors.

Rats injected with interleukin-1 (10 micrograms) and tumor necrosis factor (10 micrograms) and then exposed continuously to hyperoxia (greater than 99% O2, 1 atm) survived longer, had increased lung reduced/oxidized glutathione ratios, smaller pleural effusions, less pulmonary hypertension and improved arterial blood gases. The percentage of animals surviving for 72 hours in hyperoxia increased from 8% to 94%. Although relatively small increases in glutathione redox cycle enzymes occurred four and sixteen hours following cytokine injection, dramatic increases in all major antioxidant enzymes including superoxide dismutase, glucose-6-phosphate dehydrogenase, glutathione reductase, glutathione peroxidase, and catalase had occurred following 72 hours of exposure to hyperoxia. The protective effect of IL-1 + TNF against lethal pulmonary O2 toxicity could be partially inhibited by pre-injection of lysine acetylsalicylate or, less effectively, of ibuprofen. Recent studies have suggested that both IL-1 and TNF can induce manganese (mitochondrial) superoxide dismutase mRNA and protein synthesis in a variety of cell types. Preliminary studies suggest that IL-1 alone, in ample dosage, can provide protection against lethal pulmonary O2 toxicity. Future studies should be directed toward identification of acute phase changes in lung antioxidant enzymes, surfactant proteins and/or lipid components, enzymes needed for synthesis of surfactant phospholipids, and/or other protective proteins. Additional work also needs to be done in identifying the lung cell types in which early enzyme induction occurs. These studies should provide a better understanding of mechanisms whereby protection against pulmonary O2 toxicity can occur. An understanding of the molecular mechanisms inducing protective proteins should lead to more precise pharmacologic control of these processes.

Animals↗
PubMed1989

Cytokines increase rat lung antioxidant enzymes during exposure to hyperoxia.

Pretreatment with the combination of tumor necrosis factor/cachectin (TNF/C) and interleukin 1 (IL-1) increased glucose-6-phosphate dehydrogenase (G6PDH), glutathione reductase (GR), glutathione peroxidase (GPX), catalase (CAT), and superoxide dismutase (SOD) activities in lungs of rats continuously exposed to hyperoxia for 72 h, a time when all untreated rats had already died. Pretreatment with TNF/C and IL-1 also increased, albeit slightly, lung G6PDH and GR activities of rats exposed to hyperoxia for 4 or 16 h. By comparison, no differences occurred in lung antioxidant enzyme activities of TNF/C and IL-1- or saline-pretreated rats exposed to hyperoxia for 36 or 52 h; the latter is a time just before untreated rats began to succumb during exposure to hyperoxia. The results raise the possibility that TNF/C and IL-1 treatment can increase lung antioxidant enzyme activities and that increased lung antioxidant enzymes may contribute to the increased survival of TNF/C and IL-1-pretreated rats in hyperoxia for greater than 72 h.

Animals↗
PubMed1989

Interferons as inhibitors of interleukin 1 induced interleukin 1 synthesis.

IL-1 induces its own gene expression in cultured smooth muscle and endothelial cells and in human PBMC. IL-1-induced IL-1 may be part of a self-amplification or autocrine event in inflammation. In the present study IFN gamma consistently increased LPS-induced IL-1, but reduced the total amount of IL-1-induced IL-1 from PBMC. On a molar basis, IFN gamma and IFN alpha 2 were equally effective. IL-6 also reduced IL-1 induced IL-1 but was approximately 300-fold less potent than the two interferons. The augmentation of LPS-stimulated IL-1 by IFN gamma was observed only when added at the same time as LPS, but IFN gamma could be added several hours after stimulation with IL-1 and still suppress IL-1 production. LPS-induced mRNA for IL-1 beta at 4 hours was enhanced by IFN gamma whereas IL-1-induced IL-1 beta mRNA was reduced by 70% in the presence of IFN gamma and this reduction was not due to increase degradation of IL-1 beta mRNA. These results suggest that in inflammatory tissues where IL-1 self amplification of its own gene expression is part of the pathological process, interferons may act to inhibit this cycle.

Humans↗
PubMed1989

Tumor necrosis factor induces glomerular damage in the rabbit.

Tumor necrosis factor (TNF) is a polypeptide hormone produced by activated macrophages detectable in the circulation of experimental animals given endotoxin. Recent evidence strongly suggests that many of the deleterious effects of endotoxin in experimental animals are mediated by TNF. Because endotoxemia in experimental animals and humans is associated with glomerular damage the present investigation was designed to establish whether TNF directly induces glomerular functional and structural changes. Twenty-three rabbits were given human recombinant TNF at the doses of 0.08, 0.8, and 8.0 micrograms/kg/h as a continuous 5-hour intravenous infusion. Animals were killed at the end of the infusion. All rabbits given 0.8 and 8.0 micrograms/kg/h TNF developed anemia (Ht value decrease at 5 hours: 0.8 microgram/kg/h, 15%; 8.0 micrograms/kg/h, 16%); leukopenia (leukocyte count decrease at 5 hours: 0.8 micrograms/kg/h, 47%; 8.0 micrograms/kg/h, 59%); thrombocytopenia (platelet count decrease at 5 hours; 0.8 micrograms/kg/h, 45%; 8.0 micrograms/kg/h, 57%). Rabbits given 8.0 micrograms/kg/h also had renal failure (serum creatinine from 1.02 +/- 0.15 to 1.64 +/- 0.34 mg/dl). By light microscopy only occasional polymorphonuclear leukocytes in the glomerular capillaries were detectable in rabbits infused with 0.08 micrograms/kg/h TNF, whereas with 0.8 micrograms/kg/h TNF the presence of inflammatory cells in the glomerular capillaries was the prominent finding. With 8.0 micrograms/kg/h TNF beside leukocyte accumulation, fibrin was detected in the glomerular capillary lumens of two of eight animals. Electron microscopy found dose-dependent glomerular endothelial cell damage in animals given TNF with fibrinlike material in the capillary lumens. Glomerular changes induced by TNF were remarkably similar to those previously found in animals given endotoxin. Thus, TNF is likely to be the mediator of endotoxin-induced glomerular damage and can be regarded as a new mediator of macrophage-dependent damage in glomerulonephritis.

6-Ketoprostaglandin F1 alpha↗
PubMed1988

IL-1 induces IL-1. III. Specific inhibition of IL-1 production by IFN-gamma.

IL-1 possesses several biologic properties, some of which are associated with chronic inflammatory diseases. We have recently shown that IL-1 induces its own gene expression and, in the present studies, we have examined the effect of IFN-gamma on IL-1-induced IL-1 production. Whereas IFN-gamma increases the total amount of IL-1 (extracellular and cell-associated) produced after endotoxin stimulation of human PBMC, in the same cultures, IL-1-induced IL-1 production was markedly (greater than 70%) reduced in the presence of IFN-gamma. We observed this inhibition in the PBMC from over 40 human donors by employing non-cross-reacting RIA for either IL-1 beta or IL-1 alpha. IFN-gamma inhibited IL-1 beta-induced IL-1 alpha as well as IL-1 alpha-induced IL-1 beta production; furthermore, this inhibitory effect of IFN-gamma was unaffected by indomethacin. The ability of 100 U/ml of IFN-gamma to inhibit IL-1-induced IL-1 production was comparable to that accomplished by 10(-7) M dexamethasone. In contrast to its effect on IL-1 production from PBMC, IFN-gamma had no effect on the proliferative responses of T cells to IL-1. We conclude that IFN-gamma down-regulates synthesis of total IL-1-induced IL-1 production but up-regulates endotoxin-induced IL-1 production. These studies may explain the ameliorating effects of IFN-gamma in experimental models of IL-1-induced bone and cartilage degradation, in peritoneal fibrosis, and in patients with diseases associated with increased IL-1 production.

Dexamethasone↗
PubMed1988

Adrenalectomy sensitizes mice to the lethal effects of interleukin 1 and tumor necrosis factor.

To clarify the possible role of TNF and IL-1 in endotoxic shock, the lethality of rTNF (human and murine) and IL-1 in adrenalectomized mice was studied. Adrenalectomy, which has long been known to increase the susceptibility to endotoxin, rendered mice susceptible to TNF and IL-1 in terms of mortality. The lethality of endotoxin, TNF, or IL-1 was totally prevented by pretreatment with dexamethasone (minimal effective dose, 0.3 mg/Kg) but not by ibuprofen (10 mg/Kg).

Adrenal Cortex↗
PubMed1988

Induction of indoleamine dioxygenase by interferon in mice: a study with different recombinant interferons and various cytokines.

Since it is important the availability of a specific marker for interferon induction in vivo, we investigated the effect of different recombinant interferons and various cytokines on indoleamine 2,3-dioxygenase activity. Although with different magnitude, recombinant interferon-alpha A/D (Bgl II) hybrid, interferon-gamma and tumor necrosis factor, all increase the activity of this enzyme, whereas interleukin-1, recombinant interferon-alpha A and interferon-alpha D do not induce this activity in mice lung tissue. Dexamethasone is able to inhibit indoleamine 2,3-dioxygenase induction by lipopolysaccharide or by interferon-alpha A/D but it fails to prevent the induction by interferon-gamma.

Animals↗