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Biomedical subjects

P Chanez

Publications and source records attributed to P Chanez.

At least 127 records · Page 7Linked to original sources
PubMed1995

Stimulation of dispersed nasal polyp cells by hyperosmolar solutions.

It has been suggested that hyperosmolarity may be one of the stimuli that provoke exercise-induced asthma and rhinitis. We investigated whether changes in osmolarity could result in increased levels of mediator release from nasal cells. Cells were dispersed from nasal polyps by enzymatic digestion and were incubated for 15 minutes with solutions of varying osmolarity obtained by the addition of mannitol to Hanks' balanced salt solution. After incubation was performed, cell supernatants were removed, and the release of 15-hydroxyeicosatetraenoic acid, prostaglandin2 leukotriene B4, and fibronectin was measured. Lactate dehydrogenase was measured to assess cell viability. Epithelial cells made up 40% to 60% of cells and mononuclear cells 40% to 65%. At 900 mOsm/kg H2O, which has been suggested as the osmolarity of the fluid lining the airways during exercise, we observed a significant increase (Wilcoxon W test) in the release of 15-hydroxyeicosatetraenoic acid (p < 0.008), leukotriene B4 (p < 0.008), and prostaglandin2 (p < 0.008), but no significant increase in the release of fibronectin was seen. No significant increase was seen between lactate dehydrogenase and 15-hydroxyeicosatetraenoic acid release, suggesting that the increase in mediator levels was not caused by cell death. These results show that hyperosmolar solutions can induce activation of nasal cells, which may at least partly explain rhinitis caused by exercise.

Adolescent↗
PubMed1995

Blood monocytes of untreated asthmatics exhibit some features of tissue macrophages.

Airway macrophages are activated in asthmatic subjects. Peripheral blood monocytes from these subjects present some functional features of activation, but their membrane markers are not known. Recently a new subtype of blood monocytes, CD14+/CD16+, has been identified which possesses the characteristics of tissue macrophages. A study was carried out on nine normal subjects and 11 untreated asthmatics having variable severities of the disease to examine the phenotypic characteristics of monocytes. CD14, CD16, HLA-DR, CD11a, CD11b, CD44 and CD54 were studied using double fluorescence flow cytometry since these antigens have been defined in the CD14+/CD16+ monocytes. The functional activation of monocytes was examined using the release of superoxide anion. The co-expression of CD14 and CD16 by monocytes in terms of percentage and mean fluorescence intensity was significantly higher in asthmatics (P < 0.002 and P < 0.0001, respectively, Mann-Whitney U-test). There was no difference for the other membrane markers between asthmatics and normal subjects. Superoxide anion release was significantly increased in asthmatic subjects (P < 0.01). This study shows that most blood monocytes of asthmatics are CD14+/CD16+ and are likely to present features of tissue macrophages.

Adult↗
PubMed1995

Platelet-derived growth factor in asthma.

Platelet-derived growth factor (PDGF) controls cellular growth, migration, and differentiation. It is secreted by various cell types, including macrophages, and participates in tissue repair and epithelial regeneration. PDGF may therefore be involved in airway remodeling in asthma. This study compared the immunoreactivity of PDGF and its receptors (R alpha and R beta) in bronchial biopsies and the levels of PDGF in bronchoalveolar lavage (BAL) fluid of asthmatics and control subjects. Bronchial biopsies were done in a subsegmental bronchus of 11 asthmatics and 11 control subjects by flexible bronchoscope. PDGF AA and BB, and PDGF receptors R alpha and R beta were studied with monoclonal antibodies and revealed by immunoperoxidase staining. The percentage of subjects presenting positive staining with PDGFs and its receptors was studied in the epithelium and submucosa. PDGF AA, AB, and BB were measured in BAL fluid of 18 asthmatics and 10 controls by specific ELISA. In biopsies, there was no significant difference between asthmatics and controls for PDGF AA, BB, PDGF-R alpha and R beta (Fisher's exact test and Bonferroni's correction). Moreover, the levels of PDGF, AA, AB, and BB were similar in asthmatics and controls. This study does not support a role for PDGF in the repair processes of asthma.

Adolescent↗
PubMed1995

Increased expression of heat shock protein 70 on airway cells in asthma and chronic bronchitis.

Heat shock proteins (HSPs) appear to be involved in inflammation. Because asthma is an inflammatory disease, HSPs may be expressed. We studied the expression of HSP-70 by immunohistochemistry using the alkaline-phosphatase anti-alkaline phosphatase technique on epithelial cells and alveolar macrophages (AMs) from 19 patients with asthma, eight patients with chronic bronchitis (CB), and 13 control subjects and in bronchial biopsies from 15 asthmatics, 15 CB patients, and nine control subjects. The specificity of the antibody was confirmed by Western blotting on heated AM. The specificity of the immunostaining was confirmed by inhibition experiments. The expression of HSPs in the asthmatics in comparison with the CB patients and control subjects was significantly increased on epithelial cells (P < 0.002 and P < 0.007, respectively) and AMs (P < 0.0004 and P < 0.0002, respectively) and was significantly correlated with the severity of asthma (P < 0.005 for AMs) and the percentage of eosinophils in bronchoalveolar lavage fluid (P < 0.004). In biopsies from the asthmatics but not from the CB patients or control subjects, a positive staining for HSP-70 was observed on epithelium, mononuclear cells, and basement membrane and was correlated with the severity of asthma (P < 0.0005, P < 0.002, and P < 0.007, respectively). This study demonstrates that bronchial inflammation in asthma but not in CB may be linked to the production of HSPs.

Adult↗
PubMed1994

Heterogeneous spontaneous and interleukin-4-induced nitric oxide production by human monocytes.

The generation of nitric oxide by human monocytes has long been a subject of controversy because of the difficulty of rationalizing this production. In this work we evaluated the capacity of human monocytes to produce nitric oxide (NO) as measured by nitrite (NO2-) release. Resting unstimulated monocytes (2 x 10(6) cells/ml) were found to produce significant amounts of NO2- after 8 to 12 days in culture. This production appeared to be highly heterogeneous. Indeed, approximately, 75% of monocytes from the different donors produced up to 10 microM NO2- and were considered low producers; the last 25% produced higher amounts of NO2- (from 10 to 110 microM) and were considered high producers. In any case the spontaneous production of NO2- by monocytes was overcome in the presence of 1 mM N omega-monomethyl-L-arginine (LNMMA). This inhibitory effect was reversed in the presence of an excess of L-arginine (5 mM), indicating that this process is effectively dependent on L-arginine metabolism. Because interleukin-4 (IL-4) is considered an important NO-regulatory cytokine, its regulatory effect on this spontaneous production of NO was also evaluated. In the presence of a defined dose of IL-4 (1 to 100 ng/ml) the spontaneous production of the high-producing population of monocytes was abrogated, whereas IL-4 stimulated the production by the low-producing population of monocytes, which was suppressed in the presence of LNMMA. The present data indicate that NO production by human monocytes is heterogeneous and that IL-4 can be a potent inducer or inhibitor of this production, suggesting a variability in the activation state of these cells.

Arginine↗
PubMed1994

Modulation by interleukin-4 of cytokine release from mononuclear phagocytes in asthma.

BACKGROUND: Interleukin (IL)-4 is involved in IgE upregulation and downregulates cytokine release by mononuclear phagocytes. Mononuclear cells release greater amounts of IL-1, tumor necrosis factor-alpha, and IL-6 in patients with asthma than in control subjects, but the effect of IL-4 on cells from patients with asthma is unknown. The effects of IL-4 on the release of IL-1, tumor necrosis factor-alpha, and IL-6 by monocytes and alveolar macrophages were compared in 19 patients with asthma and 18 control subjects. METHODS: The release of IL-1, tumor necrosis factor-alpha, and IL-6 from unstimulated and lipopolysaccharide stimulated monocytes and alveolar macrophages was measured by ELISA. The effect of 30 U of IL-4 on the release of these cytokines was studied. RESULTS: Lipopolysaccharide-stimulated monocytes released significantly fewer cytokines in patients with asthma than in control subjects. IL-4 significantly inhibited cytokine release by monocytes of both groups. Unstimulated alveolar macrophages from patients with asthma released more cytokines than those of control subjects. Lipopolysaccharide induced a significantly greater increase in cytokine release in alveolar macrophages of control subjects in comparison with asthmatic subjects. IL-4 abolished the release of cytokines in alveolar macrophages from control subjects and had a minimal inhibitory effect on alveolar macrophages from patients with asthma. CONCLUSIONS: Alveolar macrophages from patients with asthma are hyperreactive but less prone to lipopolysaccharide stimulation and IL-4-downregulation than those from normal subjects.

Adolescent↗
PubMed1994

Release of cytokines by blood monocytes during strenuous exercise.

During strenuous exercise in endurance athletes, monocytes are activated and there is an acute inflammation and hypoxemia possibly due to lesional pulmonary edema. IL-6 and TNF-alpha released by monocytes may be implicated in the acute phase of lesional pulmonary edema. A study was carried out to determine whether TNF-alpha and IL-6 are released during strenuous exercise, and, if adrenalin released during exercise alters their generation. Ten young and six master athletes underwent an incremental exercise test. Arterial blood was drawn at rest, at the end of the exercise, and 20 minutes afterwards. Monocytes were isolated and incubated for 18 hours in the presence or absence of adrenalin. Il-6 and TNF-alpha were measured in monocyte supernatants. The spontaneous release of IL-6 or TNF-alpha was increased in young athletes when compared to older subjects. The spontaneous release of TNF-alpha was increased, but not significantly, by exercise and there was no correlation between the release of IL-6 and TNF-alpha and lung function measured during hypoxemia. Adrenalin inhibited the release of IL-6 or TNF-alpha. Correlations were observed between the in vitro release of IL-6 or TNF-alpha and age, VO2max, maximal ventilation and maximal power output of the subjects.

Adult↗
PubMed1994

Quantification and localization of HLA-DR and intercellular adhesion molecule-1 (ICAM-1) molecules on bronchial epithelial cells of asthmatics using confocal microscopy.

An increased expression of HLA-DR and ICAM-1 molecules on bronchial epithelial cells has been observed in asthmatic patients. The aim of this study was to evaluate the localization and to quantify the spontaneous expression of HLA-DR and ICAM-1 on bronchial epithelial cells recovered by bronchial brushing of nine asthmatics and nine controls. Epithelial cells constituted over 95% of cells recovered as shown using an anti-cytokeratin MoAb. Expression of HLA-DR and ICAM-1 was studied using indirect immunofluorescence and confocal microscopy. The intensity of fluorescence of epithelial cells expressing HLA-DR and ICAM-1 was significantly (P < 0.003) increased in asthmatics. In asthmatics, but not in controls, the expression of both molecules was localized in the cytoplasm on the apicolateral portions of the cells. This study shows an up-regulation in the expression of HLA-DR and ICAM-1 molecules by bronchial epithelial cells from asthmatics and a localization of these molecules within the cell.

Adult↗
PubMed1994

Modulation of phenotypic and functional properties of normal human mononuclear phagocytes by granulocyte-macrophage colony-stimulating factor.

In asthma, alveolar macrophages (AMs) are hyperreactive releasing large amounts of mediators and expressing high levels of surface markers. Granulocyte-macrophage colony-stimulating factor (GM-CSF) upregulates monocytes and AMs, and may be involved in the hyperreactivity of AMs. The effects of GM-CSF were tested on monocytes and AMs from normal subjects by examining the expression of factors thought to be upregulated in asthma. After various incubation times of GM-CSF, the expression of CD23 and beta 2-integrins (CD11a, CD11b, CD11c) was studied by FACS and the release of sCD23 was measured by ELISA. The priming and stimulatory effects of GM-CSF were tested on monocytes and AMs and the release of leukotriene B4 (LTB4) was measured by ELISA. GM-CSF induced the expression of CD11c and CD23 and the release of sCD23. GM-CSF primed and stimulated monocytes and AMs to release LTB4. The effects of GM-CSF may explain partly the hyperreactivity of AMs in asthma.

Adult↗
PubMed1994

Cell proliferation in the bronchial mucosa of asthmatics and chronic bronchitics.

In chronic inflammatory diseases, cells are recruited but may also derive from local proliferation. In normal bronchial epithelium, under 5% of cells are in cycle but in asthma and chronic bronchitis, proliferation may occur. Cycling cells can be identified by immunohistochemistry using PC10 monoclonal antibody (Proliferating Cell Nuclear Antigen, PCNA). We enumerated PCNA-positive cells (labeling index = LI) in bronchial biopsies of 11 healthy non-smokers (HNS), seven healthy smokers (HS), 30 non-smoking asthmatics (NSA), six smoking asthmatics (SA) and 18 chronic bronchitics (CB). Twenty non-small cell lung cancer patients were used as positive control subjects. Ciliated and secretory cells were PCNA-negative. Basal cells were PCNA-positive in one of the 11 HNS (LI = 0.18 +/- 0.60), none of the seven HS, two of the 30 NSA (LI = 0.05 +/- 0.20), two of the six SA (LI = 2.4 +/- 4.3) and 11 of the 18 CB (LI = 12 +/- 20). In smokers, PCNA positivity correlated with tobacco consumption (Rho = 0.62, p < 0.0008) and in patients with chronic bronchitis, with the degree of metaplasia (tau = 0.815, p < 0.0001). The submucosa of most subjects showed no PCNA immunoreactivity. These findings suggest that the bronchial mucosa of nonsmokers is not hyperproliferative, even in asthmatics. Tobacco smoking increases PCNA immunoreactivity, possibly leading to the metaplasia of chronic bronchitis.

Adolescent↗
PubMed1994

Phenotypic and functional modulation of normal human alveolar macrophages by histamine.

Alveolar macrophages (AM) play a regulatory role in asthma. AM from asthmatics are activated, release increased amounts of cytokines, and express higher levels of the low affinity receptor for IgE (Fc epsilon RIIb/CD23b) and receptors for adhesion molecules. The bronchial microenvironment may modulate the phenotypic and functional characteristics of AM. On AM from normal subjects, the effects of histamine were studied on the expression of adhesion molecules (LFA-1, ICAM-1) and CD23b as well as on the release of fibronectin. The expression of LFA-1, ICAM-1, and CD23b was examined by immunocytochemistry using the alkaline phosphatase-anti-alkaline phosphatase technique. The expression of CD23b mRNA was studied by in situ hybridization. The release of fibronectin was measured by enzyme immunoassay. We found that histamine induced in a dose- and time-dependent fashion a significant increase of AM expressing the three membrane markers and a significant increase in the release of fibronectin. The maximum effect of histamine was observed after an incubation of 12 to 24 h and a dose of 1 microM. The histamine effects were specific, since they were significantly inhibited by an H1-blocker, pyrilamine, used at a concentration of 10 microM. The effect of an H2-blocker (ranitidine, concentration of 10 microM) was inconstant. Cycloheximide blocked the histamine effects, suggesting that it requires protein synthesis for its action. This study provides an in vitro model of cellular interaction between mast cells and AM, which might be relevant in the airway inflammation in asthma.

Adult↗
PubMed1994

Enhancement of reactive oxygen species formation in stable and unstable asthmatic patients.

There is increasing evidence to suggest that human blood polymorphonuclear neutrophils (PMNs) and monocytes play an important role in the inflammatory processes of asthma. In asthmatic patients, PMNs and monocytes were shown to be activated more than in healthy subjects. We investigated the capacity of these two cell populations to generate reactive oxygen species (ROS) in stable and unstable asthmatic patients. The two populations of asthmatic patients were identified by asthma activity, as expressed by clinical events occurring within 2 weeks prior to the study. Oxygen species formation was analysed for isolated purified PMNs and monocytes (Mos) by chemiluminescence (CL) using lucigenin and luminol as luminescent probes. CL was determined on nonstimulated and on phorbol myristate acetate (PMA)-stimulated cells. The stimulatability coefficient (PMA-stimulated/nonstimulated cell ratio) of each cell population was then calculated. Resting PMNs and Mos generated significantly greater amounts of ROS in stable asthmatic patients, and much more in unstable asthmatic patients, as compared to healthy subjects, both in lucigenin and luminol enhanced CL. Non O2.- ROS production from PMA-stimulated PMNs and Mos was identical in unstable asthmatic patients and in healthy subjects, whereas a significant decrease was observed in stable asthmatic patients, as assessed by luminol enhanced CL. PMA-stimulated cells showed no difference in O2.- generation, as assessed by lucigenin enhanced CL. However, the stimulatability coefficient of all asthmatic patients was always significantly lower than that of healthy subjects. These results suggest that there are differences in priming and stimulation of Ros production from PMNs and Mos between stable and unstable asthmatic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Acridines↗
PubMed1994

Low-affinity receptor for IgE on human bronchial epithelial cells in asthma.

Bronchial epithelial cells are activated in asthma but the mechanisms underlying this activation are poorly understood. We tested the possibility that bronchial epithelial cells recovered by brushing from 15 asthmatic and 11 control subjects may be activated by an IgE-dependent mechanism. The expression of the low-affinity IgE receptor (CD23) was studied by immunocytochemistry using the alkaline phosphatase anti-alkaline phosphatase technique and immunofluorescence using confocal microscopy. Four of eight allergic asthmatic patients and none of the seven non-allergic asthmatic or control subjects had a positive expression of CD23. The functional activity of CD23 was examined in the cells recovered from these subjects by stimulating them with IgE/anti-IgE. 15-HETE was not released but endothelin was released in the three or four asthmatic patients who had a positive expression of CD23. None of the other subjects released any endothelin. This study suggests that bronchial epithelial cells of asthmatic patients may be directly activated by an IgE-mediated mechanism.

Adult↗
PubMed1994

[Mechanisms of bronchial hyperreactivity. Role of the epithelium].

Bronchial epithelial cells are present all along the airways. They play a role of barrier and protect the airways against inhaled pollutants. However it is known to day that they could play an active role, through synthesis and release of mediators which modulate the airway muscles, the epithelium permeability and the vascular tone. Shedding of the epithelium is a constant feature of the asthmatic airways as can be observed directly on the bronchial biopsies and indirectly through and increased number of epithelial cells in the bronchoalveolar lavage fluid. The epithelial shedding is well correlated to the bronchial hyperreactivity. In vitro, bronchial epithelial cells release higher quantities of 15 HETE, endothelin and PGE2 in asthmatics than in normal control subjects. They express HLA-DR and ICAM-1 in higher quantities in asthmatic patients. Bronchial epithelial cells might play an important role in inflammatory lesions which are observed in asthmatic patients. They could be a good target for new therapeutic approaches in asthma.

Animals↗