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Biomedical subjects

M Drouet

Publications and source records attributed to M Drouet.

At least 55 records · Page 3Linked to original sources
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

[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

Modification of HLA expression on peripheral lymphocytes and monocytes during aging.

Immunosenescence involves modifications of humoral and cellular immunity. Here we report the analysis of human leukocyte antigen (HLA) expression on T lymphocytes, B lymphocytes and monocytes of 58 healthy subjects aged 23-95 years old. Using a double staining immunofluorescence and flow cytometry analysis, we have determined the percentages of cells expressing HLA class-I and HLA-DR antigens. The number of antigenic sites expressed per cell were evaluated for HLA-ABCw, HLA-A, HLA-B, HLA-DR locus with a flow cytometry quantification technique. With advancing age, we observed: (i) a significant decrease of the percentage of T cells and B cells expressing HLA-A products; (ii) a decrease of the number of HLA class-I antigenic sites expressed per cell on the three populations tested, predominantly on B cells and in a locus-dependent fashion; (iii) a decrease of the number of HLA-DR molecules expressed per T cell, although the percentage of T cells expressing DR products was increased; (iv) a significant diminution of the percentage of B cells expressing HLA-DR molecules, without changes of the number of HLA-DR antigenic sites per cells. These changes in HLA expression with increasing age could contribute to the decreased level of immunologic responsiveness observed with ageing and contribute to the modification of antigen recognition.

Adult↗
PubMed1998

Functional studies of maturing myeloid cells during ex vivo expansion for treatment of aplasia: feasibility of ex vivo expansion from cryopreserved bone marrow cell samples.

Ex vivo expanded CD34+ progenitor cells from fresh or cryopreserved primate bone marrow, induced to granulocytic differentiation with growth factors, were investigated to determine whether myeloid cells produced in liquid cultures have the normal biologic functions needed for the treatment of patients with neutropenia following high-dose chemotherapy or therapeutic or accidental radiation exposure. Human and simian (baboons or macaques) CD34+ cells were cultured with granulocyte-colony stimulating factor (G-CSF), stem cell factor (SCF), interleukin-1 (IL-1), IL-3, and IL-6, and assessed at 14 days of culture for their capacity to respond to different functional tests. Immunostaining revealed that human ex vivo expanded cells contained myeloperoxydase (MPO, 82% +/- 8%) and lactoferrin (LF, 30% +/- 6%) in their granules. Maturation of cultured cells was associated with stimulated chemotactic responsiveness and respiratory burst activity (superoxide anion and hydrogen peroxide production) in expansions from human, baboon, and macaque CD34+ progenitor cells. Mature cells obtained from ex vivo expansion of selected cryopreserved human bone marrow CD34+ cells presented reduced but significant functional activities (chemotactic responsiveness and hydrogen peroxide production) when compared with human peripheral blood neutrophils. The validation of nonhuman primate ex vivo expansion systems may permit their use as models of irradiation. The feasibility of ex vivo expansion from cryopreserved bone marrow cell samples may offer considerable opportunity for banking bone marrow for autologous transfusion.

Anemia, Aplastic↗
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

[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

[Importance of the urinary leukotriene E4 level. Preliminary study].

Post-anesthesia anaphylactic reactions or those seen during drug provocation tests with a systemic clinical reaction may be confirmed by the sequential release into blood of plasma histamine, tryptase and leukotriene C4 and into urine of urinary methylhistamine and leukotriene E4.

Acetaminophen↗
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

[Latex allergy. Risk factors in anesthesiology].

Epidemiological studies show an increasing frequency of the responsibility of latex in allergy accidents during operations (1). The frequency of the responsibility of latex in the anaesthetic medium develops moreover in parallel with the frequency of latex allergy generally (in the professional and non-professional fields).

Allergens↗
PubMed1997

Membrane isoforms of human immunoglobulins of the A1 and A2 isotypes: structural and functional study.

As for IgM, human IgA occurs either as soluble molecules in plasma and various other body fluids, or as membrane-bound molecules on differentiated B cells, where they are part of the B-cell receptor for antigen (BCR). We studied the structure of transcripts encoding the membrane-anchored alpha-chain of the human BCR alpha, which may be present in two different forms resulting from alternate splicing of the alpha-chain mRNA (type I or type II). The ratio of type I versus type II did not vary upon stimulation of a B-cell line with various cytokines. Rather, it differed strikingly in cells expressing either the IgA1 or IgA2 isotype of the BCR alpha, with virtually no type II alpha-chain in the latter. Co-modulation experiments also yielded different results for both isotypes, since they demonstrated a physical association of both membrane (m)IgA1 and mIgA2 with CD79b, the beta component of the BCR Ig alpha/Ig beta heterodimer, but only of mIgA1 with CD19. Whatever the isotype, the BCR of the IgA class was able to carry out signal transduction upon cross-linking by specific monoclonal antibodies but, in contrast to mIgM, it relied mainly on the entry of extracellular Ca2+ rather than on the release of intracellular stocks.

Alternative Splicing↗
PubMed1997

[Does the pork/cat syndrome constitute a predisposition to heparin allergy?].

Observations are reported of two heparin-allergic patients (in one case, urticaria and in the other urticaria and asthma). These two patients show a curious association of the pork/cat syndrome, previously described (1, 2), that is an association of sensitivity to cat epithelia and pork meat. Since the heparins used nowadays are of porcine origin, the question is raised of a possible causal link that may exist between these 2 allergies. It seems that the possibility of association of these two allergies is much more likely than chance encounter.

Adult↗
PubMed1997

[Contribution of flow cytometry to allergologic diagnosis].

The technique of Flow Cytometry for activation of basophils (TAB), expressed as the marker CD63, is at present one of the pathways of research applied to drug allergy. In this work are reported the results of TAB of Pneumoallergens and Hymenoptera venoms. TAB can define better than total IgE the atopy of the subject: in effect the fluorescence of the basophils is emphasized in comparison with non-atopic subjects. This hypothesis has been confirmed by a study of three groups of subjects. With regard to drug allergy, it is important to study patients in whom the observations have been documented very objectively by clinical history and positive skin tests to the drug, compared with a negative reference to the same drug. So, TAB has been shown to be very useful in diagnosis of allergy to certain drugs, such as the Myorelaxants.

Allergens↗