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Biomedical subjects

C Pecquet

Publications and source records attributed to C Pecquet.

At least 19 recordsLinked to original sources
PubMed2006

The Src tyrosine kinase Hck is required for Tel-Abl- but not for Tel-Jak2-induced cell transformation.

Tel-Abl and Tel-Jak2 are fusion proteins associated with human haematologic neoplasms. They possess constitutive tyrosine kinase activity and activate common downstream signalling pathways like Stat-5, PI3-K/Akt, Ras/MapK and NF-kappaB. In this study, we showed the specific requirement of Src family members for the Tel-Abl-mediated cell growth, activation of Stat5, PI3-K/Akt and Ras/MapK while dispensable for Tel-Jak2. Hck was found strongly phosphorylated in Tel-Abl-expressing Ba/F3 cells and sensitive to imatinib mesylate treatment, providing evidence that Hck is a target of Tel-Abl tyrosine kinase activity. Overexpression of a kinase dead form of Hck inhibits the proliferation of Ba/F3 cells expressing Tel-Abl as the phosphorylation of Akt and Erk1/2. These results argue for an important role of Hck in Tel-Abl oncogenic signalling.

Benzamides↗
PubMed2005

Head and neck atopic dermatitis and malassezia-furfur-specific IgE antibodies.

BACKGROUND: Atopic dermatitis of the head and neck (HNAD) has been recognized as a separate entity. Malassezia furfur, a lipophilic yeast, is considered to be a pathogenic allergen in this form of atopic dermatitis. OBJECTIVE: The purpose of this study was to determine the level of IgE anti-M.-furfur antibodies and their relation to the severity of the disease. METHODS: IgE anti-M.-furfur antibodies were assayed in 106 patients with HNAD. Controls included 25 patients with non-HNAD, 20 with nonatopic dermatitis and 16 with seborrheic dermatitis (including 4 with AIDS). RESULTS: There was a highly significant correlation between the level of anti-M.-furfur IgE and clinical severity. Furthermore, there was a significant but smaller correlation between total IgE and clinical severity. In patients with HNAD, total IgE was higher amongst men. CONCLUSION: IgE anti-M.-furfur antibodies are a good and specific marker for HNAD. IgE M. furfur levels are strongly correlated with the severity of the disease.

Adolescent↗
PubMed2003

[Chronic urticaria, thyroiditis and autologous serum test].

INTRODUCTION: The autoimmune nature of certain forms of chronic urticaria remains debatable. Aim of the study. To find a correlation in terms of autoimmune pattern between chronic urticaria and thyroiditis using the autologous serum test and the search for anti-thyroid antibodies. PATIENTS AND METHODS: Study in a single center of 59 patients having consulted for urticaria that had progressed for more than six weeks and without precise etiology. An autologous serum test was conducted and anti-thyroid autoantibodies were searched for in the serum stored after the test. RESULTS: Out of 59 patients, 51 had an interpretable autologous serum test and 57 underwent research for anti-thyroid antibodies. Twelve patients out 57 (21 p.cent) exhibited one or more types of positive (n=10) or borderline (n=2) anti-thyroid antibodies, and eight out of 12 (66.6 p.cent) had a known thyroid disease before the onset of urticaria. The systematic blood test permitted the discovery of 4 cases of unknown anti-thyroid antibodies. The symptoms regressed in two of these patients without any specific treatment, one patient was treated with L thyroxin for hyperthyroidism without any improvement in the symptoms and one other patient had normal thyroid function. Among these 12 patients, 11 underwent autologous serum tests, but only 3 of them exhibited clearly positive results and one was doubtful. CONCLUSIONS: Within the limits of this study, we found a 21 p.cent rate of patients with chronic urticaria exhibiting one or more anti-thyroid antibodies. The positivity of the autologous serum test does not appear to be related with autoimmune thyroid disorders.

Adolescent↗
PubMed2002

An epidemic of allergic contact dermatitis due to epilating products.

Over a period of 19 months, 33 cases of acute allergic contact dermatitis from Veet epilating waxes and/or the accompanying tissue (Reckitt Benckiser, Massy, France) were observed in France and Belgium. The lesions started on the legs and spread to other parts of the body, especially the face, and were sometimes so severe that hospitalization and/or systemic corticosteroids were required. Primary sensitization occurred as early as after the first application in several patients. Patch tests were performed in 26 of the patients and produced strong positive reactions to the tissue (25 times) and/or the wax (13 times). The allergenic culprits in the wax were modified-colophonium derivatives (colophonium in the standard series testing negatively in all except 4 patients), while methoxy PEG-22/dodecyl glycol copolymer and to a lesser degree lauryl alcohol turned out to be the main causal allergens in the tissue.

Adolescent↗
PubMed2002

[Anisakis simplex and immediate hypersensitivity reactions].

BACKGROUND: Anisakis simplex is one of the nematode worms that parasitize sea mammals. When its larvae are accidentally ingested by humans, they can infect the host, resulting in anisakiasis manifested by digestive symptoms, or they may cause an allergic reaction, which in some cases may be severe. CASE REPORTS: We report three cases of acute urticaria associated with abdominal pain, and hypotension in two of them, starting two to six hours after ingestion of raw fish. The diagnosis of an allergic reaction caused by Anisakis simplex was based on the clinical histories and positive tests for anisakis-specific IgE. DISCUSSION: In patients with acute urticaria associated with abdominal symptoms, a history of ingestion of raw fish in the preceeding hours is evocative of gastro-allergic anisakiasis. In association with symptomatic treatment, gastrointestinal endoscopy allows the larvae to be visualized and removed, which may relieve the symptoms and provide a diagnosis before the results of skin testing and serological assay are known.

Adult↗
PubMed2000

[Allergic risk of aprotinin].

OBJECTIVE: To analyse the risk of anaphylactic reaction with the administration of aprotinin, either by i.v. route or as a biological sealant application and to propose updated guidelines in accordance with current data of the literature. DATA SOURCES: Search in the Medline data base of articles in French, English and German, published since 1960, using following key words: aprotinin, allergy, anaphylaxis. STUDY SELECTION: All categories of articles on this topic have been selected. DATA EXTRACTION: Articles have been analysed for history, incidence and mechanisms of anaphylactic reactions, symptomatology, factors of risk, diagnosis and precautions of use. DATA SYNTHESIS: Aprotinin is widely used for decreasing preoperative bleeding, especially in cardiac and orthopaedic surgery. This heterologue protein can cause anaphylactic reactions in 0.5 to 5.8% of patients, depending of the inclusion criteria. They are mediated by IgG and IgE antibodies. Aprotinin has also a direct, non specific, histaminoliberation effect. The clinical presentation includes various degrees of severity, up to cardiac arrest. Documented factors of risk are a previous parotinin administration, 15 days to 6 months before, and intolerance to beef meat, white of egg, cheese and milk. The immediate biological diagnosis is obtained on assessing the degranulation of basophiles (histamine) and mastocytes (tryptase), as well as the concentration of anti-aprotinin antibodies (RAST IgE), with a test of inhibition. The secondary assessment, six weeks later, includes prick-tests and intradermoreactions if the former are negative. The mean precaution consists to search factors of risk at preanaesthetic assessment. The predictive value of systematic prick-tests has not yet been validated. Anti H1 and anti H2 premedication is inefficient. A test dose can trigger a severe reaction. CONCLUSION: Considering a significant anaphylactic risk, aprotinin administration becomes only licit after a careful evaluation of the benefit-risk ratio.

Anaphylaxis↗
PubMed2000

[Anaphylactic reactions to aprotinin: intradermal diagnostic tests] .

A 66-year-old patient, undergoing heart surgery, developed an anaphylactic reaction following the first administration of a test-dose of aprotinin. Skin tests were performed six months later. Prick-tests with 10(-2) and 10(-1) aprotinin dilutions were negative but intradermal reaction with a 10(-3) dilution was clearly positive. The level of aprotinin specific IgE was high, both in the serum obtained before surgery and in the one sampled on the day of the testing. As no reaction was observed during the tests, skin-testing and specific IgE appear to be an interesting alternative to a potentially dangerous test-dose, but they both need further evaluation.

Aged↗
PubMed1999

Validation of a flow cytometric assay detecting in vitro basophil activation for the diagnosis of muscle relaxant allergy.

BACKGROUND: Anaphylactic reactions during anesthesia are mainly the result of muscle-relaxant (MR) drugs. Skin tests, serologic detection of specific IgE, and in vitro leukocyte histamine release are used to investigate MR allergy. OBJECTIVE: We describe a new assay that is based on the detection by flow cytometry of the altered expression of plasma membrane molecules of MR-activated basophils. METHODS: For this assay, which we have named the BASIC assay, basophils are incubated in vitro with MR, after which they are fixed and then triple labeled with fluorescein-conjugated anti-CD63, tandem dye R-phycoerythrin-cyanin 5.1 conjugated anti-CD45, and R-phycoerythrin conjugated anti-IgE. The resulting B asophils' A ltered S urface I mmunofluorescence is detected by flow C ytometry (BASIC). RESULTS: Forty-one patients who had an allergic reaction during general anesthesia and 23 control subjects without such a history were studied. All included subjects' basophils were tested in the BASIC assay with at least 4 MR: suxamethonium, gallamine, vecuronium, and pancuronium. After reaction of the basophils of the MR-allergic patients with MRs, increased surface expression of CD63 and CD45 and decreased expression of IgE were detected. Increased expression of CD63 was observed most frequently and it was stronger than the alteration of the 2 other markers. Cross-reactivity between MRs commonly occurred. MRs diluted 10(-1) activate the basophils of the control subjects, suggesting that at relatively high concentrations MRs are also nonspecific basophil activators. CONCLUSION: In the diagnosis of MR allergy, the BASIC assay has a good specificity but a low sensitivity, and it correlates strongly with skin test results. It is currently appraised for the diagnosis of anaphylactic reaction induced by other classes of drugs.

Adult↗
PubMed1995

Flow cytometric monitoring of allergen induced basophil activation.

Human basophils express many clustered differentiation antigens (CD), including CD45; however, none are specific for these cells. In a previous study, we described a two-color immunofluorescence procedure, employing antibodies to CD45 and IgE for the cytometric evaluation of basophils. In the present work, we show that when sensitized basophils are stimulated by allergenic preparations, they demonstrate an upregulation of CD45 as well as a decrease in anti-IgE binding. Since CD45 antigen modulation was observed with all aeroallergens tested and the decrease in IgE expression varied with allergenic preparations, the measurement of CD45 upregulation was used to evaluate basophil activation. Using this approach, reproducible results were observed when atopic patients were tested at different time intervals. In addition, we show that the upregulation of CD45 on allergen stimulated basophils is a very rapid phenomenon that is observed after a few minutes and that this rapid flow cytometric method can also be used for investigations on nonallergenic mediators of basophil stimulation such as calcium ionophores.

Adult↗
PubMed1993

Flow cytometric evaluation of human basophils.

The expression of CD45 and IgE cell surface antigens on human leucocytes was studied by flow cytometry. More than 80% of sorted cells that expressed low CD45 (CD45dim) and high IgE (IgEbright) antigen site density were identified as basophils. Immunomagnetic depletion of the CD45dim-IgEbright cell subset by a biotin-coupled anti-IgE antibody and streptavidin-coated magnetic beads was greater than 90%, and more than 80% of cells binding significant numbers of beads exhibited the morphological characteristics of basophils. Interestingly, when the cell staining was performed in the presence of calcium and magnesium, we observed a significant increase of CD45 and an equivalent decrease of IgE cell surface expression, as well as an IgE concentration dependent diminution of the number of CD45dim-IgEbright cells.

Antibodies, Anti-Idiotypic↗