Biomedical subjects

B Le Bon

Publications and source records attributed to B Le Bon.

5 recordsLinked to original sources

PubMed1992

Inflammatory response to acute inhalation of endotoxin in asthmatic patients.

Inhalation of 20 micrograms endotoxins (from the membrane of Gram-negative bacteria) has been reported to induce a bronchial obstructive response in asthmatic subjects. The aim of the present study was to evaluate in asthmatic patients the possibility of an inflammatory response to inhaled endotoxins. Eight patients with mild asthma were submitted to bronchial challenge tests, in a single-blind trial, on Day 1 with control solution and on Day 7 with 20 micrograms endotoxin of Escherichia coli (026:B6). Local inflammatory response was indirectly evaluated by the degree of bronchial hyperresponsiveness (BHR) expressed as PD20 FEV1 histamine (the dose of histamine inducing a 20% decrease in FEV1) at 0, 6, 24, and 48 h and 7 days. Systemic inflammation was investigated by sequential blood determinations of total (and differential) white cells, complement anaphylatoxin C5a, interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), and C-reactive protein (CRP). A significant (p < 0.01) bronchial obstructive response was demonstrable 45 min after lipopolysaccharide (LPS) inhalation, lasting 5 h. Comparing the level of BHR after control inhalation, a significant (p < 0.05) increase in BHR was shown 6 h after LPS, partially normalized at 24 and 48 h. A short peak in TNF-alpha at 60 min (p < 0.05) and an increase in total white blood cells (p < 0.01) and neutrophil polymorphonuclear neutrophils at 360 min (p < 0.05) and of CRP at 24 and 48 h (p < 0.05 and p < 0.01) were significant. The other blood parameters did not change significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗

PubMed1992

[Pneumopathy secondary to the improper use of a dust-removing spray].

We report the case of a 24 year-old woman who presented constitutional symptoms with dyspnoea on exertion accompanied by an interstitial pneumonitis in both lower lobes. The history revealed an excessive use of household dust-away cleansing spray. The diagnosis was established by bronchoalveolar lavage associated with appropriate steining. The early diagnosis is critical because of the progression to fibrosis and the risk of cancerisation.

Adult↗

PubMed1991

Domestic endotoxin exposure and clinical severity of asthma.

Endotoxins are potent pro-inflammatory substances present in several natural environments and in commercial house dust extracts. To investigate the possible effect of chronic endotoxin exposure on asthma, 28 patients with perennial chronic asthma (20 allergic to house dust mite and eight intrinsic asthmatics) were evaluated during a 4-month period (lung function, clinical and immunological criteria). At the same time, two house dust samples were collected from each patient's home to determine total house dust weight (mg/m2), endotoxin concentration and house dust mite antigen content (evaluated indirectly by guanine content with HPLC method). The mean (+/- s.d.) endotoxin concentration, as measured by quantitative Limulus assay was 2.59 (+/- 3.41) ng/mg house dust, ranging from 0.12 to 20 ng/mg. The mean guanine content was 0.13 (+/- 0.16) mg/100 mg house dust. There was no correlation between endotoxin and house dust mite concentrations. Patients were compared according to the low or high grade exposure to dust, endotoxins and guanine. Compared with patients with low grade (less than or equal to 5.6 ng/ml) exposure, subjects exposed to high endotoxin concentrations (greater than 5.6 ng/ml) showed a significant increase in dyspnea (median 2.6 vs 3.3; P less than 0.05) and treatment (median 14 vs 44.3; P less than 0.01) scores, oral corticosteroid (median 0.0 vs 13.5 mg/24 hr; P less than 0.01) and beta 2-mimetics (median four vs eight puffs/day; P less than 0.01) intake, and a significant decrease in FEV1/FVC (median 84.5 vs 67% of predicted value; P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Effect of endotoxin contamination on the antigenic skin test response.

Bacterial lipopolysaccharides (LPS), the major part of endotoxin, are proinflammatory substances present in the natural environment. Lipopolysaccharides enhance allergen-induced histamine release from human basophils of allergic subjects. The aim of this study was to assess the LPS activity on the allergy skin test response. Twenty patients allergic to house dust mite (HDM) underwent skin prick tests with LPS (E coli 026: B6 serotype) at concentrations of 1, 10, 100 micrograms/mL, with HDM extracts at different dilutions, and with solutions of LPS mixed with HDM. Endotoxin alone did not induce any immediate skin response; LPS had a synergistic effect on the HDM skin response both in terms of flare [27.4 +/- 2.8 mm, 26.6 +/- 3.3 mm, 28.1 +/- 2.5 mm versus 20.7 +/- 3.6 mm, respectively in presence of LPS 1 (P less than .02), 10 (P less than .05), 100 (P less than .01) micrograms/mL] and wheal response [6.4 +/- 1.0 mm, in presence of LPS 100 micrograms/mL versus 4.9 +/- 1.1 mm in absence of LPS (P less than .05)]. On the other hand, a possible LPS synergistic action on the histamine skin response was evaluated in ten normal subjects but the results were not significant. These findings show that LPS increases the allergy skin response probably due to a mechanism including a potentiation of the IgE receptor activation rather than an increase of the skin response to the release mediators.

Adult↗

PubMed1990

Caustic intoxication.

After a retrospective study of 17 cases of caustic intoxication in the intensive care unit, the epidemiologic, pathophysiologic, clinic and therapeutic aspects are reviewed. The following procedure is suggested: early endoscopies, abstention of any gastric lavage, corticosteroids and empiric antibiotic therapy and the most early possible introduction of a parenteral nutrition.

Adolescent↗