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Biomedical subjects

F de Blay

Publications and source records attributed to F de Blay.

At least 37 records · Page 2Linked to original sources
PubMed2001

Urticaria and rhinitis to shrubs of Ficus benjamina and breadfruit in a banana-allergic road worker: evidence for a cross-sensitization between Moracea, banana and latex.

BACKGROUND: We report the case of a road worker with a food allergy to banana, who developed urticaria and rhinitis when cutting shrubs of Ficus benjamina and breadfruit. He did not develop an allergy to latex of Hevea brasiliensis. RESULTS: Sensitization to latex of F. benjamina, H. brasiliensis, breadfruit and banana was demonstrated using skin tests and specific IgE measurements. RAST inhibitions procedures showed that specific IgE to breadfruit latex cross-reacted more strongly with latex of H. brasiliensis and banana than with latex of F. benjamina with the same extract. CONCLUSION: Given the wide distribution of Moracea trees in tropical regions, sensitization to latex of H. brasiliensis and banana could be a consequence of sensitization to Moracea members; F. benjamina does not seem to be the only Moracea responsible for cross-allergy with latex and fruit. Consequently, it seems interesting to test other members of the Moracea family in patients sensitized to latex of H. brasiliensis and banana. Sensitization to breadfruit could be a risk factor for sensitization to latex of H. brasiliensis.

Adult↗
PubMed2001

[Mites and their allergens: identification and extermination methods].

Mite allergens are the main allergens in indoor environment. Using different means of assessing exposure to house dust mites (Acarex-test, major allergen (Der p 1 + Der f 1, Der p 2 + Der f 2), content measured by ELISA) has allowed better identification of mite reservoirs and allergens in patients' homes. House dust mite control measures are based on the knowledge of factors contributing to mite development, especially indoor relative humidity. Mite allergen avoidance strategies include 3 different methods: avoidance of mite producing allergens, elimination of mite reservoirs, especially textile reservoirs, dwellings designed so as to inhibit mite proliferation. Only controlled trials can estimate patients' compliance with proposed avoidance measures. Avoidance protocols should be adjusted to each individual by medical indoor environment counselors in order to optimize mite allergen reduction.

Allergens↗
PubMed2000

Anaphylactic shock during endodontic treatment due to allergy to formaldehyde in a root canal sealant.

A 41-yr-old patient experienced an anaphylactic shock reaction caused by formaldehyde in a root canal sealant during endodontic treatment. The clinical events, positive skin tests, and a high level of immunoglobin E to formalin RAST (class 4) suggest the involvement of immunoglobin E-dependent mechanisms toward formaldehyde. This very infrequent observation in endodontic therapy focuses attention on the different pathological manifestations related to formalin, their mechanisms, and the prevention possibilities in dentistry.

Adult↗
PubMed2000

[Elimination of airborne allergens from the household environment].

Exposure to allergens could be either a risk factor of sensitization and nonspecific hyperresponsiveness in genetically predisposed patients or a risk of onset of asthma attack in certain allergic asthma. During the past 20 years, in western countries the houses have become higher and the number of furred pets have increased and have been more kept inside the house which makes probable that exposure to indoor aeroallergen has increased. The development of new methods of allergen measurements allows a more precise identification of allergen source and reservoirs, an assessment of allergen exposure and a monitoring of allergen eviction methods. Concerning mite allergens, controlled studies which showed a clinical efficacy are those with a global mite eviction and at least a 6 months follow-up for cat and dog allergens, high efficiency-filters air cleaners or vacuum-cleaners are able to reduce airborne cat or dog allergen levels. According to the increasing number of papers about allergen eviction, it seems logical to propose allergen eviction as "first line treatment" of allergic asthma. In the future, it would be interesting to develop biological markers to identify more accurately patients who have a clinical improvement after allergen eviction.

Adolescent↗
PubMed1999

Repeated inhalation of low doses of cat allergen that do not induce clinical symptoms increases bronchial hyperresponsiveness and eosinophil cationic protein levels.

The aim of this study was to investigate whether repeated exposure to subclinical doses of cat allergens, not inducing asthma symptoms, could affect eosinophil cationic protein (ECP) levels in bronchoalveolar lavage (BAL) or in peripheral blood, without the appearance of clinical symptoms. Twelve patients with mild asthma, all sensitized to cats and not exposed to cat allergen at home, underwent a series of inhalations of cat allergen or placebo for 8 days over 2 weeks. A methacholine challenge was performed before and after the allergen and saline exposures, and BAL and blood were sampled for ECP measurements and eosinophil counts. No patients experienced asthma symptoms. However, PD20 methacholine (geometric mean) decreased significantly from 263 microg before to 126 microg after inhalation of allergen. Inhalation of saline did not induce any significant change in PD20. The change in log PD20 before and after cat allergen exposure was statistically different from the change in log PD20 before and after saline. Median ECP levels in BAL and serum increased significantly after allergen exposure, from 0.8 to 3.1 microg/l (p<0.02) and from 15.9 to 31.4 microg/l (p<0.05), respectively. No change was observed after saline inhalations. The change in BAL and serum ECP levels was statistically significant compared to that in the control group. The number of eosinophils did not change, however, nor did IL-5 and RANTES levels in BAL and serum. In conclusion, our results show that (1) exposure of asthma patients to repeated low doses of allergen, which did not provoke any clinical symptoms, is capable of inducing a local eosinophil activation associated with an increase in nonspecific bronchial hyperresponsiveness and (2) the increase in serum ECP levels due to eosinophil activation precedes the occurrence of asthma symptoms and may thus be a marker of allergen exposure in allergic asthma.

Administration, Inhalation↗
PubMed1999

[Domestic pollution (other than tobacco)].

Pollution of the air of the interior of premises are generally less understood than exterior town atmospheric pollution. Now the time spent at home is considerable, around 80%. Aerocontaminants are of chemical, biological or particulate nature. Amongst asthmatics, internal NO2 is capable of producing an asthmatic crisis, perhaps by a direct effect of the pollutant and perhaps by potentiation of the bronchial response to the allergen. COV and formaldehyde may have a bronchial effect on asthmatics, at significant levels that are rarely found in a domestic environment. Endotoxins present in domestic dust may also be a serious co-factor in asthmatics who are allergic to mites. Concerning allergens, identification and quantification of immunodominant proteins of the principal pneumoallergens of the internal environment has emphasized the great diversity of levels, and given a comparison of the link between the level of allergen in the air and dust, and the development of the sensitization of a predisposed subject. Measurement of the aerodynamic behaviour of pneumoallergens has led to a better understanding of the physiology of allergic asthma. Nevertheless it is appropriate to follow the work that tries to assess the relative importance of each of these factors, both in allergic sensitization and in the clinical response to the allergen. Understanding the respective roles played by the different domestic pollutants should allow an improvement in diagnosis and treatment of pathologies that are linked to the domestic environment.

Adolescent↗
PubMed1999

[Exploration of respiratory allergies and prevention].

Respiratory allergies are found in more than 50% of the asthmatics. Allergen sources and their secondary reservoirs are better known. The different methods of exploration of allergic asthma consist of clinical history, skin tests, and in vitro tests particularly measurement of specific serum IgE. Specific challenge tests are realized with nebulized allergenic extracts as well as in the realistic manner with substances in occupational environment. It is equally important to evaluate the allergenic environment, especially by simple but informative techniques such as the Acarex test for mites. The eviction methods are the same for primary prevention (to prevent sensitization) as well as for the secondary prevention (to reduce the disease exacerbation in the patients already sensitized). The eviction methods mainly concern the allergens of mites, domestic animals, cockroaches and the molds.

Allergens↗
PubMed1999

Skin testing with wild-type recombinant birch pollen allergens and hypoallergenic modified molecules.

UNLABELLED: Our aim was to compare the allergenic activity of wild type rBet v 1 with recombinant Bet v 1 derivatives (rBet v 1 fragments, dimer and trimer) with potentially reduced anaphylactic activity by skin testing in a French population. METHODS: Among the 36 birch pollen allergic patients included in the study, 29 were tested by skin prick testing and 30 by intradermal injections with purified monosubstances: rBet v 1 fragments (F1: aa1-74 and F2: aa75-160), Bet v 1 dimer and trimer. Intradermal tests were performed by the endpoint intradermal titration method. Tests were performed over a period of 6 months (before, during and after birch pollen season). RESULTS: All patients showed lower reactivity with the modified rBet v 1 allergens, both in skin prick- and intradermal tests. In 25 and 23 out of 29 patients the lowest concentration of fragment 1 and 2 respectively, resulting in a positive prick test was 100 fold higher than the lowest concentration of monomer resulting in a positive prick test. For dimer it was 100 fold or more in 25 out of 29 patients, and for trimer it was 100 fold or superior in 26 out of 29 patients. By intradermal testing, the end point concentration was 160 fold higher for trimer than for monomer in 24 patients and 40 fold higher in 5 patients. For the 2 fragments the end point concentration was 160 fold higher in 20 out of 22 patients. CONCLUSION: rBet v 1 fragments and trimer may represent candidate molecules for immunotherapy of birch pollen allergy with reduced risk of anaphylactic side effects.

Allergens↗
PubMed1998

Effects of various vacuum cleaners on the airborne content of major cat allergen (Fel d 1).

BACKGROUND: It has been shown that a vacuum cleaner (VC) can increase airborne cat allergen levels. This study aimed to compare the degree of leakage of airborne Fel d 1 levels among five different VCs, both under laboratory conditions and in an apartment with cats. METHODS: Three of the VCs were marketed as antiallergic: a HEPA filter VC (VC A), a water impingement and HEPA filter VC (VC B), and a foam fabric filter VC (VC C). The other two were standard VCs: VC D and VC E. VCs were tested in a 20 m3, airtight, experimental room and in a 53 m3 living room in an apartment with three cats. Air was sampled with a glass-fiber filter and an impinger at 20 l/min for 30 min before, during, and after vacuuming. Airborne Fel d 1 was measured with a two-site monoclonal ELISA assay. RESULTS: In the experimental room, no airborne Fel d 1 level was measured before using the VCs. After introducing a dust sample containing Fel d 1 in the VCs, we found that VCs A, B, and E did not provoke any increase in airborne Fel d 1. In contrast, VCs C and D significantly increased airborne Fel d 1 levels (GM: 4.9 and 5.3 ng/m3, respectively). In the apartment, all VCs induced an increase in airborne Fel d 1, which was carried by particles greater than 5 microm. However, VCs C and D provoked significantly greater increases in airborne Fel d 1 than VCs A, B, and E (P=0.0001). CONCLUSIONS: Our results suggest that: 1) The two VCs with leakage in the experimental room had greater leakages in the apartment. 2) In the apartment with cats, all VCs provoked increases in airborne Fel d 1, primarily carried by large particles. 3) Given the increased marketing of "antiallergic" VCs, further studies are needed to standardize methods for testing airborne allergen leakage by VCs.

Air Pollutants↗
PubMed1998

Up- and down-regulation by glucocorticoids of the constitutive expression of the mast cell growth factor stem cell factor by human lung fibroblasts in culture.

Stem cell factor (SCF) is a major mast cell growth factor that promotes differentiation and chemotaxis of mast cells and inhibits their apoptosis. SCF therefore may be involved in diseases associated with an increased number of tissue mast cells such as asthma, for which the major treatment is glucocorticoids. In this study, we evaluated the effect of the glucocorticoid budesonide on the constitutive expression of SCF by human lung fibroblasts in primary culture. Budesonide (0.1 microM) induced a time-dependent biphasic effect on SCF mRNA and protein production. A short treatment (2.5-10 hr) induced an inhibition of SCF protein accumulation (-58% at 2.5 hr) and mRNA expression (-69% at 2.5 hr), associated with an accelerated decay of SCF mRNA and with a decrease in SCF gene transcription observed by nuclear run-on assay. Longer treatment (24-72 hr) led to increases in SCF protein accumulation (+64% at 48 hr) and mRNA expression (+125% at 24 hr) as a consequence of transcriptional activation. Similar effects of a decrease followed by an increase in SCF production were observed using another glucocorticoid, dexamethasone. Overall, our results show that glucocorticoids potently regulate SCF expression in human lung fibroblasts, successively decreasing and increasing SCF mRNA levels according to treatment duration. Such time-dependent modulation of SCF levels may explain some current discrepant findings about the effects of glucocorticoids on SCF production and may have functional consequences during glucocorticoid treatment, such as asthma therapy.

Budesonide↗
PubMed1998

[Asthma and household chemical pollutants (with the exception of tobacco)].

The relationship between allergens in a domestic environment and asthma has been extensively studied and it is only recently that studies have suggested the possibility of the role of chemical pollutants in the internal environment in the genesis of asthma. The pollutants studied are oxides of nitrogen (nitrogen dioxide NO2), volatile organic components (COV), formaldehyde, ozone (O3) and sulphur dioxide (SO2). The level of nitrogen dioxide in the interior of houses may be greater than those met outside. Normal values are 400 mcg per metre3 per hour and 150 mcg per metre3 in twenty four hours. In asthmatics challenge test to nitrogen dioxide and epidemiological studies suggest that internal nitrogen dioxide is capable of provoking asthmatic crises either by a direct pollutant effect or by potentialising the allergenic crises either by a direct pollutant effect or by potentialising the allergenic response of the bronchi. COV and formaldehyde are liberated by urea formaldehyde foams and by chipboard furniture. The levels of COV and formaldehyde inside a house may be up to 10 times higher than those outside. COV and formaldehyde perhaps would have an effect on the bronchi in asthmatics at significant levels which are rarely found in the domestic environment. Ozone is an external pollutant. However, from 5-80% of the external concentrations may be found inside some locations. Thus, in certain conditions which are relatively rare, the interior concentrations of dwelling places may attain levels which are capable of inducing, in healthy subjects who are sensitive to ozone, a drop in the FEV1. As regards asthmatics, only experimental work has been able to show any bronchospastic effect of ozone, either by a direct effect on the bronchi or by the potentiation of a bronchial response to allergens. It would be convenient to perform some epidemiological studies to determine if there is a relationship between exposure to ozone internally and to bronchial changes. The concentrations of SO2 inside houses increases when coal is burnt. The levels provoking a bronchial reaction are much greater than those found inside houses. The data and the literature which is mostly recent seems to stress the role of NO2 ozone and SO2 as a factor which might favour asthmatic crises induced by allergens in atopic subjects. However, other studies will be necessary to confirm the initial data.

Adult↗
PubMed1998

Serum eosinophil cationic protein measurements in the management of perennial and periodic asthma: a prospective study.

We performed a prospective study in order: 1) to determine whether a correlation could be found between serum eosinophil cationic protein (ECP) levels and clinical and functional status in perennial asthmatics during a 5 month prospective study; and 2) to evaluate the relationship between allergic exposure and ECP levels in periodic asthmatics. Two groups of asthmatic patients were selected: a group of acutely ill perennial asthmatics and a group of periodic asthmatics. The acutely ill perennial asthmatics (n=22, mean age=39.4 yrs) were included on the basis of hospitalization for acute asthma. At the end of the hospitalization, there was a 5 month follow-up of clinical, functional and medication scores, as well as eosinophil counts and ECP levels. The periodic asthmatic group was composed of asthmatics sensitized to birch and tree pollens (n=10, mean age=33.8 yrs). The same measurement were performed on this group, before, during and after the pollen season. Under corticosteroid treatment in the acutely ill patients, there was a significant decrease in serum ECP levels between the first day of hospitalization and the day of discharge (mean: 23.2 microg x L(-1) and 9.5 microg x L(-1), respectively; p=0.006). No correlation was found between the clinical status, functional status and serum ECP levels during the 5 month follow-up. A significant increase in ECP levels was found in periodic asthmatics during the pollen season. Our results suggest that serum eosinophil cationic protein is a useful marker of allergen exposure and of acute asthma treatment. This could be of importance in the prevention and follow-up of allergic asthma; the value of serum eosinophil cationic protein measurements in the day-to-day management of adult asthmatics needs to be further clarified.

Acute Disease↗
PubMed1998

[Experimental studies of the effects of atmospheric pollutants].

Experimental studies in man are an indispensable complement to epidemiological studies and experimental studies on animals. They aim at understanding the mechanisms of action of the main pollutants and at knowing their thresholds of triggering of the acute effects on the respiratory system. The studies made in man involve controlled exposure to different atmospheric pollutants, with measurement of the functional respiratory repercussions, studies of modification of the cells in broncho-alveolar lavage, as well as experimental protocols that combine inhalation of allergen and exposure to atmospheric pollutants by allergic subjects. The main results that are available are reported to distinguish those from normal subjects and those who are allergic. More recent protocols are based on exposure to concentrations that are close to atmospheric concentrations or those that are met in work places. The main data in the literature are reported in this journal and concern SO2 acid aerosols, dioxides of nitrogen, ozone and diesel particles. Pathogenic hypotheses concerning the undesirable effects of atmospheric pollutants on the respiratory system are considered.

Aerosols↗
PubMed1997

Dust and airborne exposure to allergens derived from cockroach (Blattella germanica) in low-cost public housing in Strasbourg (France).

BACKGROUND: Although a strong association between allergy to cockroach (CR) and asthma has been observed in the United States and Asia, there are little data about the extent of exposure to CR allergen in Europe. OBJECTIVE: To determine the levels of CR allergens in dust samples from apartments in Strasbourg and to determine the concentration and size of CR allergens in the air. METHODS: Nine apartments in a public housing complex were chosen on the basis of visual evidence of CR infestation. Levels of CR allergens (Bla g 1 and Bla g 2) in kitchen and mattress dust samples were measured by immunoassay with the use of monoclonal antibodies. Air was sampled for 3 to 8 hours in the kitchen under undisturbed conditions, during artificial disturbance, and during normal domestic activity by using an impinger and a parallel glass fiber filter and at flow rates of 2 to 20 L/min. Airborne CR and mite allergens were measured concurrently in the bedroom of one apartment before, during, and after artificial disturbance. RESULTS: High levels of Bla g 1 and Bla g 2 were found in kitchen dust from the nine apartments (geometric means of 3919 U/gm [range 530 to 14306 U/gm] and 497 U/gm [range 73 to 1946 U/gm], respectively). Under undisturbed conditions, airborne CR allergens were not detectable in any of the apartments. During vigorous artificial disturbance, Bla g 1 and Bla g 2 were detectable in air samples from seven apartments (geometric means of 4.5 U/m3 [range 0.7 to 17.2 U/m3] and 1.0 U/m3 [range 0.4 to 3.4 U/m3], respectively). Both allergens were predominantly collected on the first stage of the impinger, and 76% to 80% of the airborne allergen was associated with particles greater than 10 microns in diameter. The levels were significantly higher than those collected on the second or third stages of the impinger (p < 0.001). A comparison of the levels of mite and CR allergens showed that the airborne properties of these allergens were similar, that is, measurable only during disturbance and not detectable 30 minutes after disturbance. CONCLUSION: Levels of CR allergen in low-cost public housing in Strasbourg can be as high as or higher than the levels measured in towns in the United States. CR allergens become airborne during disturbance and are primarily associated with particles greater than 10 microns in diameter. Patients with asthma living in urban areas of Europe in housing prone to CR infestation should be evaluated for sensitization and exposure to CR allergens.

Air Pollution, Indoor↗
PubMed1997

Post-traumatic pleural effusion: demonstration of local complement consumption.

The present case report describes a 27-year-old patient who presented with post-traumatic pleural effusion. Analysis of the pleural fluid showed hypereosinophilia (990 mm-3), a decreased level of total complement, and decreased levels of C3 and C4 fractions (less than 50% of normal serum levels), indicating a local consumption mechanism for complement. Complement serum levels (CH50, C3, C4) were normal. All other aetiologic possibilities were eliminated. This case suggests that the immunopathological mechanism of post-traumatic pleural effusion may involve activation of the classical pathway of complement and a recruitment of inflammatory cells such as eosinophils.

Adult↗
PubMed1997

Invasive pulmonary aspergillosis with cerebromeningeal involvement after short-term intravenous corticosteroid therapy in a patient with asthma.

The present case report describes a case of invasive pulmonary aspergillosis with cerebromeningeal invasion in an asthmatic non-immunocompromised patient. This fatal complication occurred despite early anti-fungal antibiotherapy after a 2-week course of intravenous corticosteroid therapy for treatment of an exacerbated asthma. Diagnostic and therapeutic procedures are discussed.

Aged↗