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Biomedical subjects

S Hassoun

Publications and source records attributed to S Hassoun.

At least 19 recordsLinked to original sources
PubMed2000

Development of perfluorocarbon tracer technology for underground leak location.

A method has been developed for the atmospheric sampling and analysis of four perfluorocarbon tracer (PFT) compounds simultaneously at the parts per trillion (ppt) level. PFTs were pre-concentrated using adsorbent tube air sampling. Analysis was achieved by thermal desorption (TD) and gas chromatography (GC) with electron capture detection (ECD). Efficient separation of the PFTs from the other sample constituents was achieved by use of a capillary porous layer open tubular (PLOT) GC column without the need to cool the GC oven to sub-ambient temperatures using liquid coolants (M. de Bortoli and E. Pecchio, J. High Resolut. Chromatogr., 1985, 8, 422) or for a catalytic destruction step to remove interferents (T. W. D'Ottavio, R. W. Goodrich and R. N. Dietz, Environ. Sci. Technol., 1986, 20, 100). Results from test field trials with two volatile PFTs that were buried to simulate an underground leaking cable were successful. The PFTs were detected above ground level to pinpoint the leak position. The highest tracer concentrations were detected within 1 m of the simulated leak positions 2 days after tracer burial. The developed technology was applied to an oil leaking high voltage electricity cable. One PFT was added to the cable oil which enabled detection of the oil leak to within 3 m. The reported method has many advantages over currently used leak detection methods and could, in the future, be applied to the detection of underground leaks in a variety of cables and pipes.

Chromatography, Gas↗
PubMed2000

[The wasp-mosquito syndrome: extension of cross-allergenicity to the horsefly].

The crossed allergenicity between wasp venom and mosquito extract was shown during recent work based on clinical observations and correlation studies between different biological parameters, indicating an IgE-dependent biological mechanism. A common protein was identified by Immunoblot. From observation of one of our patients involved in this work, we examined the possibility of the extension of crossed reactivity between wasp, mosquito and horsefly. In effect, our patient presented an anaphylactic reaction with neurological complications from attack on the central grey nucleus, shown by IRM; the immunological study showed a common protein between wasp venom and the total extracts of mosquito and horsefly.

Adult↗
PubMed1999

A catalogue of urban hydrocarbons for the city of Leeds: atmospheric monitoring of volatile organic compounds by thermal desorption-gas chromatography.

A method has been developed for the speciation and quantitative determination of hydrocarbons in urban air in the city of Leeds. Hydrocarbons were pre-concentrated by adsorbent tube air sampling and analyzed using thermal desorption and gas chromatography with flame ionization detection and structural confirmation by mass spectrometric detection. While automated volatile organic compound (VOC) analyzers produced data for a maximum of about 30 compounds simultaneously, with the method described here, a total of 68 C6-C12 hydrocarbons were measured simultaneously in one analysis at parts per billion (ppb) levels. Several monitoring surveys were performed, one during the winter of 1993 and the other in the summer of 1994, at a number of sites to investigate the levels of VOCs identified in the urban air of Leeds.

Absorption↗
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

[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

[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

[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

[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↗
PubMed1998

[Postoperative allergic complications: the role of the anesthetist in conducting the immuno-allergic investigation].

When peri-anaesthesia anaphylactic and/or anaphylactoid reactions occur, anaesthetist is the first investigator: the quality of immuno-allergological investigations depends on these initial investigational procedures. We have used sample kits for several years in order to make easier the immediate investigation. From retrospective analysis of the allergic complications which happened in 1997, the importance of these sample kits as well as the anaesthetist's part in the immuno-allergological management are examined. Nine observations were itemized (0.047%): 3 generalized erythema observations (grade I), in which atracurium was incriminated twice, and propacetamol once; 2 observations of grade II, in which vecuronium (elevated tryptase) and atracurium were incriminated; 4 anaphylactic shocks, in which three neuromuscular blocking drugs (suxamethonium, vecuronium and pancuronium), and one antibiotic (cloxacilline) were incriminated. The use of sample kits allowed an early diagnosis approach, confirmed by skin tests. Diagnosis should be thought closely between anaesthetists and immunologists for investigations.

Adolescent↗
PubMed1998

[Allergic immunobiology and anesthesiology].

A protocol has been produced for the study of anaphylactic accidents that occur post-operatively that allows definition of the anaphylactic origin, and so reactions that are mediated by IgE in post-operative accidents. This protocol occurs in two stages, the first is done in the minutes and hours that follow the anaphylactic accident, and the second a month or 6 weeks afterwards. At first, we evaluate the sequential study of the liberation of the mediators of anaphylaxis, plasma histamine, serum tryptase, urinary methylhistamine and, more recently, leucotriene E4. The second study is devoted to reactions that are mediated by IgE, essentially, specific serum IgE, tests of activation of basophils by flow cytometry, measurement of leucotriene C4 and skin tests. A study on 16 subjects has evaluated and validated the protocol and shown a significant level of correspondence of results between the sequential measurement of mediators on one hand and on the other the search for IgE-mediated reactions every time that there was an anaphylactic reaction.

Adolescent↗
PubMed1998

[Predictive value of the allergologic profile in anesthesia and resuscitation].

The allergic history to anaesthetics in general and especially to synthetic myorelaxants, poses few etiological diagnostic problems in practice, because of on one hand the excellent collaboration between Anesthetists and Allergologists in the CHU at Angers and on the other because of the great sensitivity of skin testing. Why then have a predictive history for myorelaxants? The results of a study at the CHU at Angers on 15 patients showed sensitivity to anaesthetics in general (myorelaxants 86%, Diprivan) and/or an antibiotic, latex were very encouraging. One 15 new general anaesthetics a single minor incident was seen: the 15 patients had benefited from a predictive history.

Adolescent↗
PubMed1998

[Importance of realistic tests for drug allergy: apropos of a clinical case].

Drug allergy is the most difficult area in Allergology because: Clinical polymorphism and specially physiopathology (IgE-dependent hypersensibility reaction, cyclo-oxygenase inhibitor, etc.). Feeble specificity and sensitivity in the basic immunoallergic investigation (Skin tests, specific IgE). Very frequently his necessitates recourse to REALISTIC TESTS of drug re-introduction under clinical and biological surveillance (HSI mediators: histamine/tryptase/urinary methyl histamine) to produce a diagnosis.

Adult↗
PubMed1997

[Physiopathology of food allergy].

Food allergy is defined by a mixture of digestive and or extra-digestive clinical symptoms, "rhinitis, asthma, eczema, etc" secondary to contact with a food and/or a preservative and/or addition to the immune system of the organism, with its origin in an excessive humoral and/or cellular response, called HYPERSENSITIVITY. For this to occur, food allergy needs conjunction of several parameters. Predisposing factors Genetics, with facility to produce IgE. Reduction of the defences of the digestive system. Usual foods

Digestive System↗
PubMed1997

[Allergy to mosquitoes and use of new immunobiological parameters].

With regard to an observation of anaphylaxis after a mosquito bite, we have shown by new immunobiological parameters and clinical investigations: Skin tests, specific IgE, Tests of Activation of basophils by flow cytometry (on basophils and total blood) and measurement of Leucotriene LTC4, the objective reality of the mechanism of IgE-dependent hypersensitivity (HS). This observation is correlated with rare work in support of true IgE-mediated allergy to mosquito 9 authors having used skin tests, PK in 1984 and immunoblot.

Adult↗
PubMed1997

[Food allergy: definition--physiopathology].

Food allergy is defined by a mixture of digestive and or extra-digestive clinical symptoms, "rhinitis, asthma, eczema, etc" secondary to contact with a food and/or a preservative and/or addition to the immune system of the organism, with its origin in an excessive humoral and/or cellular response, called HYPERSENSITIVITY. For this to occur, food allergy needs conjunction of several parameters. Predisposing factors Genetics, with facility to produce IgE. Reduction of the defences of the digestive system. Usual foods.

Digestive System↗