Bombesin, calcium homeostasis and tumour growth.

Bombesin and its analogues are a family of naturally occurring neuropeptides with potent mitogenic activity. The ability of this agent to induce Ca2+ transients is likely to be relevant in this context, but it is not yet clear whether the effect of bombesin on cell growth is directly and exclusively related to its capacity to increase cytoplasmic Ca2+ levels. The present study investigates the affect of bombesin on cytoplasmic Ca2+ concentrations in human tumour cells of different origin: lung adenocarcinoma, lung adenocarcinoma with properties of alveolar epithelial cells (A549 cell line), mesothelioma and uterine carcinoma (HeLa cell line). Furthermore, the ability of bombesin to promote the in vitro growth of the same cells has been analysed. This agent was able to induce a transient rise in cytoplasmic Ca2+ levels in tumour cells from all lines. In lung adenocarcinoma cells, but not in the other tumour cells, bombesin produced Ca2+ transients followed by a moderate but sustained elevation of Ca2+ levels. The effects of bombesin on tumour cell cytoplasmic Ca2+ levels were compared to those of other agents, i.e. adenosine diphosphate (ADP), collagen or thrombin, which have been reported to induce Ca2+ transients in tumour cells. Bombesin and ADP increased cytoplasmic Ca2+ levels in all cell lines, while collagen and thrombin gave rise to higher transients, but were effective only in some tumour cells and not in others. Furthermore, bombesin was able to stimulate in vitro growth of all the tumour cells, except for the A549 cells, in which this agent induced a slightly lower increase in cytoplasmic Ca2+ concentration. These data may aid a better understanding of the complex relationship between the Ca2+ mobilizing and mitogenic activities of bombesin and may be of general interest when considering the biological effects of growth-stimulating factors.

Urinary levels of bombesin-related peptides in a population sample from northern Italy: potential role in the pathogenesis of chronic obstructive pulmonary disease.

Bombesin-related peptides (BRP) are present in the lung and have various biological functions, including modulation of lung maturation. Many recent studies have suggested that BRP have a pathogenic role in airway wall remodeling in chronic obstructive pulmonary disease. The aim of this cross-sectional survey was to evaluate the distribution of urinary BRP excretion as a indirect marker of pulmonary BRP production and to assess the prevalence of smoking, chronic respiratory symptoms, chronic obstructive pulmonary disease, and asthma in a population sample from northern Italy. Associations between urinary BRP excretion and several respiratory and nonrespiratory variables were also evaluated. The only variable tested that was significantly predictive of high urinary levels of BRP was the presence of respiratory symptoms. In contrast to previous studies, smoking per se was not significantly associated with urinary BRP levels.

Bombesin enhances monocyte and macrophage activities: possible role in the modulation of local pulmonary defenses in chronic bronchitis.

Increased lung levels of bombesin-related peptides (BRPs) have been described in smokers and in patients with chronic obstructive pulmonary diseases (COPDs). Moreover, previous studies have shown that BRPs are endowed with immunoregulatory activities. The aim of the present study was to assess the in vitro influence of synthetic bombesin on the activity of mononuclear phagocytes obtained from healthy donors and from COPD patients. Bombesin significantly enhanced in vitro phagocytosis of monocytes and alveolar macrophages in both groups of subjects, restoring deficient phagocytosis in a group of COPD patients. Moreover, bombesin stimulated superoxide anion production and interleukin-8 release by peripheral monocytes.

Effects of 3'-hydroxyfarrerol (IdB 1031), a novel flavonoid agent, on phagocyte products.

The novel flavonoid compound 3'-hydroxyfarrerol (IdB 1031) was tested in a number of in vitro experiments in order to ascertain its effects on some functions and products of human phagocytes. We found that IdB 1031 did not depress neutrophil phagocytosis and chemotaxis, whereas at a concentration of 10(-4) M it significantly (p < 0.05) reduced the fMLP-triggered neutrophil production of superoxide anion. At the same concentration, the compound decreased the release of neutrophil elastase and myeloperoxidase from neutrophils (p < 0.05). We also found evidence that IdB 1031 is a non competitive, reversible inhibitor of human neutrophil elastase (Ki 200 microns). Finally, IdB 1031 at the concentration of 10(-5) M significantly reduced the release of tumor necrosis factor-alpha and interleukin-8 from monocytes (p < 0.05). We conclude that, in spite of the moderate activity displayed by IdB 1031, these findings add to our current knowledge on the spectrum of the antiinflammatory activities of flavonoids.

Cefodizime modulates in vitro tumor necrosis factor-alpha, interleukin-6 and interleukin-8 release from human peripheral monocytes.

Among third-generation cephalosporins, cefodizime (CFDZ) has shown to modulate many functions of the host defense system against infections. The aim of the present study was to assess the in vitro CFDZ-dependent modulation of interleukin (IL)-6, tumor necrosis factor-alpha (TNF-alpha) and IL-8 release from lipopolysaccharide (LPS)-stimulated human peripheral mononuclear cells (MNCs). Two other third-generation cephalosporins: ceftriaxone (CFX) and ceftazidime (CFT), were also tested under the same experimental conditions. At concentrations ranging from 200 to 50 micrograms/ml, CFDZ significantly decreased TNF-alpha and IL-6 release from maximally (LPS 1 microgram/ml) stimulated MNCs (42% inhibition of TNF-alpha release with 100 micrograms/ml of CFDZ). On the other hand, CFDZ revealed a marked stimulatory effect on IL-8 release (200 micrograms/ml of CFDZ induced 51.5% enhancement of IL-8 release). On the contrary, both CFX and CFT failed to exert any significant effect on TNF-alpha, IL-6 or IL-8 release.

In vitro effect of bombesin-related peptides on the procoagulant activity of alveolar macrophages.

Bombesin-related peptides (BRP) are present in the lung during foetal life and are mitogenic for normal bronchial epithelial cells, pulmonary fibroblasts, and small-cell lung carcinoma cell lines. Increased levels of BRP have been described in the adult lung of cigarette smokers and in smoking related lung diseases. BRP have also been involved in the network of neuroimmune interactions, having been shown to modulate the phagocytic function of monocytes and alveolar macrophages. BRP have recently been shown to modulate the release of procoagulant activity (PCA) by human monocytes and alveolar macrophages after a 24 h culture. The aim of this study was to evaluate the effect of bombesin on cell-associated PCA of alveolar macrophages (AMs) obtained from asymptomatic subjects. In basal conditions, AMs were found to possess a low procoagulant activity, that was not affected by their preincubation (4 h at 37 degrees C) with phorbol myristate acetate (1 microgram-mL-1). On the contrary, endotoxin (lipopolysaccharide (LPS)) induced a significant increase of procoagulant activity of macrophages when used at a concentration of 1 microgram.mL-1, in the same experimental conditions; whilst a lower (1 ng.mL-1) concentration of LPS nonsignificantly enhanced cell-associated PCA. Treatment of AMs with synthetic bombesin (BN) alone (10(-6) to 10(-10) M) did not enhance cell-associated PCA, whilst a significant effect was seen when BN was added to the lower concentration of LPS (BN 10(-6) M+LPS 1 ng.mL-1: 12.6 U.10(-6) cells; LPS alone 1 ng.mL-1: 7.8 U.10(-6) cells).(ABSTRACT TRUNCATED AT 250 WORDS)

Interactions of P 1507, a new antioxidant agent, with phagocyte functions.

Toxic oxygen free radicals are believed to play a role in the pathogenesis of a number of respiratory diseases. In particular, pulmonary emphysema may occur because of the oxidative impairment of alpha 1-proteinase inhibitor (alpha 1-PI). We report in vitro data on a new thiol agent, P 1507 [N-5-(thioxo-L-prolyl)-L-cysteine], obtained in a series of experiments designed in view of its therapeutic potential in these clinical conditions. We found that P 1507 at the concentration of 5 x 10(-6) M was able to almost fully abolish the PMA-triggered PMN-induced oxidative impairment of alpha 1-PI. Protection may be due to the radical scavenger ability of P 1507, that markedly reduced superoxide anion production from PMNs. We also found that P 1507 did not significantly impair other defence mechanisms of PMNs (i.e. phagocytosis, chemotaxis and bactericidal activity). The release of cytokines (TNF-alpha, IL-6 and IL-8) from monocytes was not altered in the presence of P 1507. We conclude that the compound P 1507 may be considered for treatment of clinical conditions characterized by overload of oxidants, on the basis of its ability in preventing the oxidative damage of alpha 1-PI and of a lack of unwanted inhibitory effects towards defence mechanisms of phagocytes.

Effect of interferon alpha, interferon gamma and tumor necrosis factor on the procoagulant activity of human cancer cells.

BACKGROUND: It is not known whether the different cytokines may influence the procoagulant activity of cancer cells; the purpose of this study was to investigate the effect of interferon alpha, interferon gamma and tumor necrosis factor on the procoagulation capacity of human cancer cells cultured "in vitro" or isolated from tumor tissues. METHODS: "In vitro" cultured tumor cell lines were derived from a patient with malignant mesothelioma and a patient with lung adenocarcinoma. Cells isolated from 6 carcinomas of different origin were also investigated. The procoagulant activity of the cells before and after treatment with the cytokines was expressed as RBT U/10(5) cells or RVV U/10(5) cells. RESULTS: Short-term incubation of tumor cells cultured "in vitro" with cytokines did not modify their procoagulant activity; after longer incubation however, interferon alpha induced a significant increase in the procoagulant activity of mesothelioma cells, while interferon gamma induced and increase in the procoagulant activity of lung adenocarcinoma cells. Furthermore, short-term incubation of cells isolated from tumor tissues with interferon gamma or tumor necrosis factor resulted in a significant increase of procoagulant activity, while interferon alpha had no effect. CONCLUSIONS: Altogether, these data demonstrate that the cytokines may influence the expression of the different procoagulant activities of tumor cells.

Role of bronchial and bronchoalveolar lavage in chronic obstructive lung disease.

The authors review the role of bronchoalveolar and bronchial lavage in chronic obstructive lung disease patients. Only a few papers were published in the last ten years on this matter. In addition, data are incomplete and often conflicting, mainly because of the limited number of patients sampled and of non-standardized techniques of analysis. However, both bronchoalveolar and bronchial lavage are likely to be useful research tools to understand the pathophysiologic mechanisms underlying chronic obstructive lung disease.

Proaggregating and procoagulant activities of human mesothelioma tumor cells at different stages of "in vitro" culture.

BACKGROUND: The mechanisms of the interactions between tumor cells and the hemostatic system are not completely understood; the purpose of this study was to elucidate whether tumor cells grown "in vitro" express the same proaggregating and procoagulant activities as cells isolated from tumor tissues, and whether the activities of such cultures are constant and consistent over time. METHODS: Tumor cells were collected and cultured from the pleural fluid of a 71-year-old patient with a sarcomatous malignant mesothelioma. Platelet aggregating activity was studied by adding tumor cells to platelet rich plasma or to washed, aequorin-loaded platelets. The procoagulant activity of the tumor cells was measured by the one-stage recalcification time of different humans plasma substrates. RESULTS: Cells harvested after 4 culture passages possessed low, ADP-dependent platelet aggregating activity, while those studied after 16 or 40 passages activated platelets through the production of thrombin. In the washed platelet system and in the presence of trace amounts of platelet poor plasma, the difference in the aggregating activity of various tumor cell populations was more evident. Normal mesothelial cells did not induce platelet aggregation. Procoagulant activity (tissue factor-like) was low in normal mesothelial cells and in tumor cells after 4 passages, and it was about 10 times higher in tumor cells after 16 or 40 passages. CONCLUSIONS: Results obtained with tumor cells cultured "in vitro" should be considered with caution because their effects are different from those of freshly isolated cells and may not be constant in the different culture passages.