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Biomedical subjects

R Louis

Publications and source records attributed to R Louis.

At least 55 records · Page 3Linked to original sources
PubMed1997

Usefulness of induced sputum analysis in pulmonary diseases.

In this study, we analysed the cellular component of induced sputum in healthy control subjects (n = 30), asthmatics (n = 44), patients suffering from COPD (n = 15), pulmonary tuberculosis (PTB) (n = 14) and healthy steel workers (HSW) (n = 14). Sputum was induced by inhalation of hypertonic saline (NaCl 5%) for 20 min. When compared to the healthy control group, all the disease groups as well as the one of healthy steelworkers exhibited significantly higher total sputum cell counts. Analysis of the differential cell counts showed that there was a significant increase in % eosinophils in asthmatics, in % neutrophils in COPD, asthmatics, tuberculosis and healthy steelworkers and in % lymphocytes in pulmonary tuberculosis. Our study illustrates the feasibility and the possible clinical application of induced sputum analysis in several pulmonary diseases and shows how this technique could be useful in assessing airway inflammatory processes in subjects exposed to industrial pollutants.

Administration, Inhalation↗
PubMed1997

Correlation between bronchoalveolar lavage (BAL) fluid cell lysate histamine content and BAL fluid eosinophil count in atopic and nonatopic asthmatics.

We have compared the bronchoalveolar lavage fluid (BAL) cellular composition and the BAL cell lysate histamine content (fluorometric assay) in 28 stable mild to moderate asthmatics (atopic n = 18 and intrinsic n = 10) and 11 control subjects. When compared to control subjects, the whole group of asthmatics had a higher proportion of BAL eosinophils (p < 0.01) and metachromatic cells (p < 0.05). The BAL cell lysate histamine was increased in atopic (p < 0.05) and intrinsic asthmatics (p < 0.05) in comparison with control subjects. In the whole group of asthmatics, the BAL cell lysate histamine content correlated with the percentage of BAL eosinophils (r = 0.58, p < 0.01). This relationship was significant in both atopic (r = 0.48, p < 0.05) and intrinsic (r = 0.70, p < 0.05) asthmatics. For the whole group of asthmatics, both the BAL cell lysate histamine and the percentage of BAL eosinophils inversely correlated with the percent predicted FEV1 (r = -0.42, p < 0.05; r = -0.51, p < 0.05). We conclude that an increased BAL cell lysate histamine content correlates with airway eosinophilic infiltration and lung function impairment in mild to moderate atopic and intrinsic asthmatics. This suggests that BAL mast cells play a key role in recruiting eosinophils in the airways of asthmatics irrespective of the presence of an atopic status.

Adult↗
PubMed1997

Cell infiltration, ICAM-1 expression, and eosinophil chemotactic activity in asthmatic sputum.

We have applied the technique of sputum induction by hypertonic saline in asthmatics and nonatopic control subjects to study an array of indices of airway inflammation believed to be relevant to asthma pathogenesis. Compatible with a central role for eosinophils and mast cells in asthma, sputum of asthmatic subjects contained increased numbers of eosinophils and levels of eosinophil cationic protein (ECP) and mast cell tryptase. Eosinophil numbers, and ECP and histamine levels correlated with the degree of methacholine airways responsiveness, and ECP, tryptase, and histamine correlated with raised concentrations of albumin. Using the micro-Boyden chamber technique eosinophil chemotactic activity was identified only in the sputum from asthmatics. The correlation between the raised levels of total IgA, IL-8/IgA complexes, and tryptase and the degree of sputum eosinophilia and ECP levels, suggests possible mechanisms for eosinophil chemotaxis and activation in asthma. Row cytometric analysis of sputum lymphocytes showed an increase in CD4+ T cells and T cells expressing intercellular adhesion molecule-1 (ICAM-1) in asthma which, together with the finding of raised levels of soluble ICAM-1 in the sputum, indicates upregulation of this adhesion molecule. Finally, the proportion of CD16+ natural killer (NK) cells was reduced in the sputum of asthmatics. These observations highlight the importance of the airway inflammation in causing asthma and further confirm the usefulness of sputum induction as a tool in asthma research.

Adult↗
PubMed1996

Blood mononuclear cells mobilization and cytokines secretion during prolonged exercises.

This study was designed to compare the effects of three prolonged exercises varying in their intensity and duration, on blood mononuclear cell mobilization and cytokine secretion (IL1(1)-IL(2)). Seven healthy subjects underwent three effort trials (45 % VO(2)max during 4 h - 60% VO(2)max during 3 h - 75 % VO(2)max during 2 h) at one-month intervals. Blood samples were drawn before, different times during exercise and also after exercise. Prolonged exercises induced a transient increase in blood mononuclear cells which occurred across all intensity levels. We also observed a significant increase in plasma IL(1) level during exercise which correlates with the exercise intensity. The mean IL(1) level increased up to 2.5 times after the three proposed exercises (p <0.05). Plasma IL(2) level decreased at the end of prolonged exercises irrespective of the exercise intensity. No correlation was observed between blood mononuclear count and cytokine determination. Our data suggest that blood mononuclear cells mobilization is associated but not correlated with alterations of cytokine levels.

Adult↗
PubMed1995

Regulation of histamine release from human bronchoalveolar lavage mast cells by stem cell factor in several respiratory diseases.

We investigated the effects of stem cell factor (SCF) on histamine release (HR) from human bronchoalveolar lavage (BAL) mast cells. BAL cells were recovered from lavage performed in patients undergoing clinical bronchoscopy. SCF (0.02-20 ng/ml), which is by itself a poor secretagogue (mean +/- SEM HR: 3.7 +/- 0.9%; n = 27), strongly enhanced HR induced by anti-IgE in a concentration-related manner. Significant potentiation began at 0.2 ng/ml (30 +/- 10%; p < 0.05; n = 12) and reached a plateau at 2 ng/ml (40 +/- 10%; P < 0.01 at 2 ng/ml and 45 +/- 10%; P < 0.01 at 20 ng/ml; n = 12). In contrast, SCF failed to enhance HR induced by calcium ionophore A23187. Among the BAL cell samples initially unresponsive to anti-IgE (55% of samples), 36% (10/28) were converted to responders if the cells were shortly preincubated with SCF. In 25% of samples (7/27), SCF (20 ng/ml) caused direct HR of 10 +/- 2.1%. The mast cells which released histamine when challenged with SCF also secreted higher levels of histamine in response to anti-IgE and calcium ionophore than those nonresponsive to SCF. While interleukin (IL)-3 and IL-5 (20 ng/ml) were unable to modulate immunologic HR, GM-CSF (20 ng/ml) produced significant potentiation (P < 0.05), which was, however, smaller than that observed with SCF.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗
PubMed1995

Increased frequency of bronchial hyperresponsiveness in patients with inflammatory bowel disease.

Although bronchopulmonary manifestations are rare in inflammatory bowel disease (IBD), subclinical abnormalities have been described in up to 50% of cases. The pathophysiology of these abnormalities remains unknown. However, a latent inflammation of the bronchial mucosa secondary to the inflammation of the intestinal mucosa has been suggested. This subclinical inflammation may lead to increased bronchial responsiveness. We studied the bronchial responsiveness in 38 inflammatory bowel disease (IBD) patients, using the methacholine test. Bronchial hyperresponsiveness was defined by a PC20M < 16 mg/ml. Twenty-four healthy controls were also studied. There was no significant difference in baseline FEV1 between IBD patients and controls. However, there was a significantly greater fall in FEV1 in the IBD patients at the concentrations of methacholine tested. The frequency of bronchial hyperresponsiveness was significantly higher in the IBD population (45%) than in controls (17%; P < 0.03). Atopy, defined by skin test, was more common in IBD patients (42%) than in controls (21%). Even when only nonatopic subjects were considered, the frequency of bronchial hyperresponsiveness was significantly higher in IBD patients (41%) than in controls (5%; P < 0.02). Thus, subclinical bronchial hyperresponsiveness is common in IBD, and may be considered a further extraintestinal manifestation.

Adolescent↗
PubMed1995

Changes in bronchial responsiveness, circulating leucocytes and ex vivo cytokine production by blood monocytes after PAF inhalation in allergic asthmatics.

We investigated the effects of inhaled platelet-activating factor (PAF) on methacholine bronchial responsiveness, circulating leucocyte counts, and ex vivo tumour necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) production from blood monocytes in eight allergic asthmatics. Bronchial responsiveness was defined as the provocative concentration of methacholine causing a 20% decrease in forced expiratory volume in one second (PC20). Circulating leucocytes were counted by means of an automatic haemocytometer, and cytokines were measured with specific immunoassays. The different variables were measured before and 4, 24, 48, 72 and 168 h after a PAF (225 micrograms), a lyso-PAF (225 micrograms) and a saline bronchial challenge. When compared with lyso-PAF and saline, inhalation of PAF resulted in a significant decrease in PC20 over a period of one week. Two falls in bronchial responsiveness were identified, the first by 4 h and the second beginning 48 h and reaching a maximum by 168 h. The increases in spontaneous TNF alpha and IL-1 production which occurred during the week after both PAF, lyso-PAF and saline, did not differ significantly. Likewise, the changes in circulating neutrophil counts, characterized by a transient rise by 4 h after PAF and lyso-PAF but not saline, followed by a fall by 24 h and a persistent decrease until 168 h, were not significantly different after PAF, lyso-PAF and saline. On the other hand, in comparison with lyso-PAF and saline, inhaled PAF caused a significant protracted augmentation in circulating eosinophil counts, which was maximal by 48 h but did not correlate with the delayed decline in PC20.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1994

Potentiation of histamine release from human leucocytes by PAF.

Studies on the effects of PAF on histamine release from human leucocytes have yielded conflicting results. We therefore investigated the effects of PAF on leucocytic histamine release (HR) focusing on direct as well as on modulating effects. Peripheral blood leucocytes of normal and atopic subjects were incubated with PAF, anti-IgE and FMP for 30 min at 37 degrees C, and histamine was measured fluorometrically. Unlike anti-IgE (1/2000) and FMP (10(-5) M) which caused histamine release (HR) of 34 +/- 7% and 31 +/- 8%, respectively, PAF by itself (10(-11)-10(-5) M) failed to induce any significant HR from human leucocytes (< 3%) in normal (n = 14) and atopic subjects (n = 6). Nevertheless, in normals as well as atopics, PAF, but not lyso-PAF, enhanced anti-IgE (1/2000) and FMP (10(-5) M)-induced HR in a concentration-related manner. Maximal potentiation of histamine release caused by FMP and anti-IgE was achieved with PAF (10(-7)) (mean +/- SEM: 26 +/- 5%, n = 5, p < 0.01) and PAF (10(-5)) (mean +/- SEM: 20 +/- 7%, n = 7, p < 0.05), respectively. This potentiation was suppressed by WEB2086 (10(-5) M), a specific PAF antagonist. The time course of the enhancing effect produced by PAF was dependent on the type of secretagogue. The enhancement was nearly maximal when PAF and FMP were added simultaneously to the leucocytes, whereas a preincubation of 20 min with PAF was required to get maximal enhancement with anti-IgE. The enhancing activity of PAF on HR induced by both anti-IgE and FMP was reversed by washing the cells after preincubation. While PAF enhancement of FMP-induced HR persisted on mononuclear cell fraction containing basophils, that of anti-IgE-induced HR was considerably reduced under these conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗