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Biomedical subjects

A Sabbah

Publications and source records attributed to A Sabbah.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Basophil activation test using flow cytometry in Hymenoptera venom allergy].

The basophil activation test (TAB) clearly shows evidence to Hymenoptera venoms. Comparison of the TAB value with the clinical history allows fixation of a threshold that will anticipate the type of clinical reaction by the TAB value. For the technique of TAB 3 dilutions are used. The basophil activation values produce a threshold for each dilution. For the first dilution the threshold is 50% activation: below this threshold, 70% of patients would have a local or systemic reaction and above this threshold, 70% of patients would have a systemic allergic reaction.

Adult↗
PubMed1999

[Level of histamine in supernatants from the basophil activation test: applications to hymenoptera allergy and drug allergy--preliminary study].

Histamine Release technic consists in calculating histamine liberated by blood cells in touch with an allergen. To this day, this method is only used in Hymenoptera venom allergy diagnosis. The principle of this study is to measure histamine released by activated basophils in surnageons of Basophil Activation Test (BAT) for different allergens: Hymenoptera venoms: Bee, White Faced Hornet, Vespula Wasp. Drugs: Cefaperos, Clamoxyl, Alfatil, Rapifen, Diprivan, Nesdonal, Mivacron. A threshold of positivity (amplification factor in comparison with the control) is determined for these two classes of allergens: 45 for Hymenoptera venoms and 9 for drugs. These results, compared to the other diagnosis technics (Histamine Release, Basophil Activation Test, Prick Tests) discloses very high correlation rates in each case. This method seems to be a reliable method for Hymenoptera venom allergy diagnosis and for drugs allergy diagnosis too. However, this study is based on a few number of patients, so a significant statistic conclusion can't be expressed but it opens an interesting way of research.

Basophil Degranulation Test↗
PubMed1999

[Non-allergic rhinitis or intrinsic rhinitis? Unusual features of nickel allergy].

The clinical expression of nickel is known for its great diversity, from classical contact eczema to rhinitis, including work-related allergy, and by secondary hyperthermia to a metallic heart valve. Very often, hypersensitivity which may be of type I or type IV is secondary to contact of the hapten with sensitive cells, however some authors have reported the possibility of reactivation of lesions, especially dermatological (urticaria-eczema) by tests of oral ingestion. However, review of the literature does not mention the possibility of O.R.L. problems of the rhinitis type, from rhinosinusitis following ingestion of nickel and the two clinical cases that we report that involve one child of 11 years and one patient of 59 years, both of whom presented a serious rhinitis with a tendency to surperinfection, developing to perennial, where a patch-test to nickel was strongly positive, and who have seen an improvement in their clinical problems with a strict diet without this hapten. This confirms that the need is eventually physiopathological and suggests the necessity to search systematically for a possibility of hypersensitivity to haptens by the patch test technique in rhinitis that is labelled "non-allergic", by a negative reaginic history to pneumoallergens and trophallergens.

Adrenal Cortex Hormones↗
PubMed1999

[Chronic urticaria caused by cow's milk allergy: immediate or delayed allergy? (apropos of a case)].

Chronic urticaria has multiple etiologies, amongst them food allergy, which is not the most frequent. We report a clinical case of chronic urticaria due to cow milk, where paradoxically the responsibility of the food was shown by an epidermo test when the prick test was negative. Development confirmed the responsibility of cow milk. We discuss the mechanisms that relate chronic urticaria to delayed hypersensitivity.

Adult↗
PubMed1999

[Membrane stabilizers (chromones and ketotifen)].

The drugs called "Membrane stabilisers" are composed of cromones (sodium cromoglycate and nedocromil) and Ketotifen. They inhibit the degranulation of mastocytes by a membrane stabilising effect. Ketotifen is distinguished from the cromones by a conjoint antihistamine effect. Nowadays, the indications are for prophylactic treatment of allergic asthma, rhinitis and allergic conjunctivitis and the manifestations of food allergy. Therapeutic efficacy seems to be good in intermittent or mildly persistent asthma, especially in children or young subjects. Secondary effects are rare and generally benign, with reduced contra-indications.

Animals↗
PubMed1999

[Anti-histamines].

The use of anti-histamines remains the therapy of choice for the ensemble of allergic pathologies with a reaginic mechanism. Knowledge of the metabolism of histamine gives an understanding of a number of allergic symptoms and also clarifies the mechanism of action of the anti-histamines. Many molecules are appearing on the market, each with a more precise action on the specific H1 receptors and also carrying other pharmacological specificities of better and better study. Observance of contra-indications, in particular cardio-vascular, allows their use without reserve, whilst knowing that there are always problems of specific tolerance, that are variable from one individual to another, specially on drowsiness. The importance of stopping anti-histamines must be remembered, every time that this is possible, before making an allergic diagnosis by skin tests.

Animals↗
PubMed1999

[Corticosteroids].

The corticosteroids or glucocorticoids have a preponderant place in the treatment of allergic manifestations. They are used to ward of the inflammatory process triggered and auto-maintained by some mediators (histamine, tryptase, leucotrienes, prostaglandin, ECP, MBP ...) that are released by some cells (mastocytes, basophils, eosinophils ...) during the contest of antigen--antigen receptor site. It is essential to understand the mechanism of action of the glucocorticoids as well as their secondary effects to adapt prescriptions better.

Adrenal Cortex Hormones↗
PubMed1999

[Apropos of the evaluation and validation of in vitro tests for measurement of specific IgE].

The performances of the reagents for IN VITRO TESTS in Allergy, are very variable, in spite of the existence of registration procedures as well as those of national quality control. Most of the discrepancies have their origin in the choice of technologies used by the manufacturers (reaction support, raw materials, calibration, vigour of the process of execution). It follows from this that the characteristics must be understood and the limitations appreciated of the tests that are used, as well as their interpretation. Of such information that is accessible in the records of the National Control of Quality of the Medicines Agency, as well as in the studies that are done with the aim of evaluating analytical and/or clinical performance of available tests (this work is a review of the performances of most of the tests sold in France today). It stands out that the best borders on very mediocre and that it is indispensable, like the planned nomenclature of the medical biological consultations, to take into consideration the technique used to obtain a result for interpretation of the latter.

Allergens↗
PubMed1999

[The wasp/mosquito syndrome].

The authors describe for the first time the Wasp/Mosquito syndrome. The allergenic cross-reactivity between Vespula wasp venom and mosquito extract and the reverse rest objectively on several criteria. The frequency of the association between sensibilization to Vespula wasp venom and mosquito: In 10 subjects who had specific IgE to Vespula wasp venom 3 also had mosquito-specific IgE (30%), but out of 11 subjects with positive mosquito-specific IgE 10 also were positive with Vespula wasp venom specific IgE (about 91%). Three observations were documented showing a clinical and biological relationship between sensitisation to mosquito and wasp venom. A first patient had an anaphylactic reaction after a dozen mosquito bites. The allergy assessment confirmed sensitisation to the mosquitos, but also to Vespides (wasp, hornet) venoms. A second patient had an anaphylactic reaction after a wasp sting in 1997. From that date, he had local reactions, indeed loco-regional, to mosquito bites. The allergy assessment confirmed the double sensibilization to mosquito and wasp venom. Finally, a third patient at first had local reactions, also loco-regional, to mosquito bites, then two systemic reactions after mosquito bites. A first allergy assessment, made exclusively to hymenoptera venoms (not to mosquitos), showed a sensitivity to wasp venom and the patient, by mistake, was desensitised to wasp venom, which did not prevent recurrence after mosquito bites. After a second time, the allergy assessment for hymenoptera and mosquito, confirmed a double sensitisation (mosquito and Vespula wasp). Indirect criteria such as parallel increase in specific IgEs to Vespula wasp venom and mosquito in a patient who was desensitised only to mosquito and who had not been re-stung by wasps. Finally on direct criteria, such as: The inhibition technique by CAP RAST, which was positive in two ways: Vespula wasp--specific IgE was inhibited by mosquito extract, and vice versa. Electrophoresis, which showed a protein common to Vespula wasp venom and mosquito extract of M.W. of the order or 42KD and isoelectric point between 4.5 and 5. An immunoblot study identified this common protein with a M.W. of 44KD which is the same as hyaluronidase.

Adult↗
PubMed1999

[Allergy to sunscreens].

Introduced in the 1930s, the sun filters (chemical screens) are very widely used as they are contained in photo-protective creams and in many other cosmetics. Allergy to sun filters seems to be rare in the general population (< 2%), but more frequent in populations which are suspected of photo-dermatosis (2 to 25%). It is composed of contact allergies, but also photo contact allergies in 45 to 85% of cases. Photo-biological exploration is comprised of application of photopatches and thus is necessary together with epidermotests. Crossed allergies, though rare, may be seen between filters, but also with substances that have a close chemical structure. Treatment such as prevention, if photo-protection is necessary, rest in discarding the causal filter and use of non-allergenic mineral screens.

4-Aminobenzoic Acid↗
PubMed1999

[Chronic urticaria in sports horses].

Chronic urticaria in otherwise healthy sport horses, generally has an origin in a food allergy, accompanied by a facultative latent enteritis. Etiological diagnosis may be made by skin tests that permit a following targeted avoidance.

Animal Feed↗
PubMed1999

[Anaphylaxis caused by a mosquito: 2 case reports].

Allergy to mosquitoes that produces anaphylaxis is very exceptional. We present two observations of anaphylaxis to mosquitoes with good correlation between the clinical history and the immunological indications of which the basophil activation test proved to be effective. The many allergens of mosquitoes are contained in the juices and salivary glands and their molecular weights are between 22 and 95 kD. Specific immunotherapy, which uses whole body extracts of mosquito, gives good results of protection that induces excellent tolerance and has very good efficacy.

Adult↗
PubMed1998

Analysis of anti-IgE and allergen induced human basophil activation by flow cytometry. Comparison with histamine release.

OBJECTIVE AND DESIGN: On the basis of flow cytometric methods previously described for the analysis of human basophil activation, we present here a bi-color anti-IgE FITC, anti CD63 PE method and the correlation with histamine release. MATERIALS AND SUBJECTS: Subjects allergic to grass pollen were selected by their clinical history, skin tests and specific IgE. METHODS: Basophils gated in the lymphocyte region of the side scatter (SSC)/forward scatter (FSC) pattern were selected by their high IgE epitope density. Percentage of cells expressing CD63 marker, upregulated on activated basophil membrane, was calculated by the cytometer. Histamine released into the supernatants was measured by RIA. RESULTS: In these conditions, flow cytometric analysis of blood leukocytes showed that the selected cells had the phenotype CD14-, CD19-, CD45+, IgE++ and CD63- or + which is related to human basophil phenotype, the isotype controls being negative. The use of an anti-CD41 FITC antibody also showed the presence of aggregated platelets on the basophil membrane, CD63 antigen being, however, expressed by basophils themselves and not by platelets. Moreover, no statistical difference was observed between histamine release and flow cytometry after passive sensitization of blood donor leukocytes. CONCLUSION: Flow cytometry, as a popular method often used in the immunology and haematology departments of clinical laboratories may represent a new alternative for allergy diagnosis and basophil pharmacology.

Allergens↗
PubMed1998

Azelastine eye drops in the treatment of seasonal allergic conjunctivitis or rhinoconjunctivitis in young children.

In a randomised, multicentre study, the effect of azelastine eye drops (n = 51 patients) was compared in a double-blind manner with placebo eye drops (n = 30 patients) and in an open manner with levocabastine eye drops (n = 32 patients) during a 14-day treatment period involving 113 children (aged 4 to 12 years) suffering from seasonal allergic conjunctivitis/rhinoconjunctivitis. The primary variable was the response rate defined as the number of patients showing an improvement after three days of treatment of at least three score points, from a minimum baseline score of six, in the main ocular symptoms of itching, conjunctival redness and lacrimation (each assessed on a four-point scale). Patients discontinuing due to inefficacy were regarded as non-responders. The mean response rate in the azelastine eye drops group (74%) was significantly higher (p < 0.01) than that in the placebo group (39%) and comparable with that in the levocabastine group. The response rates assessed by the patients in their diaries were very similar. Significant differences (p < 0.01) for azelastine compared with placebo were observed on days 3 and 14 in the mean sum scores for the three main symptoms and for a total of eight eye symptoms. The overall assessment of efficacy confirmed the superiority of both active treatments compared with placebo. Adverse drug reactions were reported in 23% of placebo-, 35% of azelastine- and 38% of levocabastine-treated patients. These were mainly local irritant effects. Overall tolerability was assessed as very good or good in 80%, 84% and 91% of placebo-, azelastine- and levocabastine-treated patients, respectively. Azelastine eye drops are effective and well-tolerated in children with seasonal allergic conjunctivitis.

Child↗
PubMed1998

[Testing basophil activation by flow cytometry in the diagnosis of allergy to hymenopteran venom].

Diagnosis of allergy to hymenoptera venom must be precise and depends on indisputable bio-clinical criteria, because of specific immunotherapy for indications such as systemic and/or anaphylactic reactions. Until nowadays, diagnosis was by specific IgE, histamine release and skin tests, most often done for the venoms of wasp, honey bee and hornet at the same time since, in 7-8 cases in 10 the patients had not identified the responsible insect. Basophil activation test (TAB) by Flux cytometry and measurement of leukotriene C4 (LTC4) are new techniques of great reliability. The work shows the correlations between the different immunobiological parameters by reference to TAB by CAF and measurement of LTC4. When the overall results for mixed venoms or those for single venoms are considered, the correlations between TAB, LTC4 and the other parameters are highly significant. It can now be considered objectively that TAB by CTF and measurement of LCT4 are the two highest-performing techniques for diagnosis of hymenoptera venom allergy and so validates them.

Basophils↗
PubMed1998

[Evaluation of the quality of 2 techniques for measuring IgE: the Pharmacia CAP System (Pharmacia & Upjohn Diagnostics) and Alastat (DPC-France)].

The reliability of results given by specific IgE dosages technology is conditioned by the quality of the technology used. Analytical comparison of two techniques (Pharmacia CAP System and Alastat-DPC) shows important behaviour differences in the evaluation of the precision/reproducibility of results and in dilution tests. The Pharmacia CAP System demonstrates qualities comparable to those awaited from any immunodiagnostic test. The Alastat techniques shows high imprecision and the dilution tests make us wonder about calibration and/or ability of the support used to fix all epitopes.

Allergens↗
PubMed1998

[Gelatin allergy].

Allergy to the gelatin used as a plasma filler product has not been recognised until now. Methods used have not been validated but are composed of specific serum IgE, skin tests and histamine release by leucotrienes. The clinical observation that we report has the merit of showing the reality of an allergy that is dependent on plasma filler products due to development of a protocol which includes firstly, during anaphylactic shock, measurement of the mediators of immediate hypersensitivity and secondly, after the clinical accident, test of the activation of basophils by flow cytometry (TAB) and measurement of leucotrienes.

Aged↗