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  • 1
    Electronic Resource
    Electronic Resource
    Diamond deposition by chemical vapor deposition process: Study of the bias enhanced nucleation step (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 1870-1880 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In the case of diamond films synthesized by the microwave plasma assisted chemical vapor deposition technique (MPCVD), the bias enhanced nucleation (BEN) step has been developed to avoid the scratching pretreatment and to palliate the low nucleation density of diamond crystals on the most common substrate used: pristine single silicon substrates. This treatment that occurs before the diamond growth step often consists in the application of a negative bias voltage of the substrate/substrate holder system, which is electrically insulated from the reactor wall. In the case of the MPCVD process, this bias induces a complex superposition of two cold discharges: the microwave and the bias discharges. Unfortunately, this complex configuration leads to inhomogeneous deposits in terms of quality, nucleation rate, and thickness. Furthermore, the reproducibility of the BEN step is generally poor in terms of diamond deposits and electrical BEN parameters. In order to better understand and overcome this pretreatment step, we have studied the temporal and spatial evolution of the bias discharge according to diamond propagation (in terms of kinetic and geometrical effects) and its electron emission, the nature and the shape of the substrate holder (in terms of aging and point effects). We have shown that the presence of the bias plasma is necessary. Based on this observation, we propose a phenomenological mechanism to explain the heterogeneous deposit and the poor reproducibility. Our results with a MPCVD reactor confirm the proposed model and some experimental modifications allow us to obtain homogeneous diamond films elaborated with reproducible electrical parameters. This work would permit the synthesis of a large area of highly oriented films obtained by BEN on single silicon substrates. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.368314
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  • 2
    Electronic Resource
    Electronic Resource
    Use of CD63 expression as a marker of in vitro basophil activation and leukotriene determination in metamizol allergic patients (2003)
    Oxford, UK : Munksgaard International Publishers
    Allergy 58 (2003), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: We assessed the reliability of basophil activation test (FAST) and sulphidoleukotriene production (CAST) in the in vitro diagnosis of allergy to metamizol, evaluating its sensitivity and specificity.Methods: Twenty-six patients allergic to metamizol and 30 control individuals were studied. Skin tests with metamizol, FAST, and CAST were performed.Results: FAST sensitivity was 42.3% and specificity 100%. The PPV of FAST is 100% and the NPV 99.4%. The likelihood ratio for a positive value cannot be calculated because the specificity is 100% and the likelihood ratio for a negative value is 0.58. CAST sensitivity was 52%, and specificity 90%. The PPV of the test is 5% and the NPV 99.5%. The likelihood ratio for a positive result was 5.2 and that for a negative result 0.53. FAST detects a larger number of cases when patients are studied within the first 6 months after the clinical reaction (χ = 4.2, P = 0.04) than later. Together with skin tests, FAST allowed detection of 69.2% patients allergic to metamizol, the same as CAST 76%. The joint use of the three techniques allowed identification of 76.9% of cases.Conclusions: FAST and CAST are useful for the diagnosis of allergy to pyrazolones. Its usefulness clearly increases when recent reactions are studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1398-9995.2003.00096.x
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  • 3
    Electronic Resource
    Electronic Resource
    Variations of serum eosinophil cationic protein and tryptase, measured in serum and saliva, during the course of immediate allergic reactions to foods (2001)
    Copenhagen : Munksgaard International Publishers
    Allergy 56 (2001), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: Subjective complaints and reactions after placebo administration during food challenges (FC) may make their outcome difficult to interpret. We determined serum ECP and tryptase as tryptase in saliva during FC, looking for markers to support challenge outcomes. Methods: Twelve patients with systemic reactions after food intake and nine presenting oral allergy syndrome (OAS) underwent skin tests; total and specific IgE determination; double-blind, placebo-controlled FC (DBPCFC); and open challenges. Blood samples were collected before and 1, 2, and 5 h after challenge and saliva before and 5, 30, and 60 min after challenge. ECP and tryptase were quantified by ImmunoCAP (Pharmacia-Upjohn, Sweden). Serum tryptase of 〉10 µg/l was considered positive. Results: After positive DBPCFC (n=8), ECP rose significantly (P〈0.05) at 1-h – 16.03 (12.8) μg/l (mean [standard deviation]) – and 2-h intervals – 17.56 (10.7) μg/l – compared to basal level of 9 (6.4) μg/l. After negative DBPCFC (n=6), ECP increased from basal 9.63 (3.9) μg/l to 24.84 (14.17) μg/l at the 2-h time point. There were nonsignificant differences in ECP between patients with positive and negative FC. Two patients with positive challenge showed a tryptase level of 〉10 µg/l and only one patient with OAS showed 5.6 µg/l of tryptase 5 min after FC. Conclusions: ECP and tryptase in serum and saliva were not useful markers for FC outcomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1398-9995.2001.056006568.x
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  • 4
    Electronic Resource
    Electronic Resource
    Allergen-induced basophil activation: CD63 cell expression detected by flow cytometry in patients allergic to Dermatophagoides pteronyssinus and Lolium perenne (2001)
    Oxford, UK : Blackwell Science, Ltd
    Clinical & experimental allergy 31 (2001), S. 0 
    Details
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background In this study, we determined by flow cytometry the percentage of basophils activated after in vitro stimulation by allergens and expressing the CD63 marker. The diagnostic reliability of the technique was assessed as well as its correlation with other in vitro diagnostic parameters.Methods Fifty-three patients suffering from asthma and/or allergic rhinitis following sensitization to Dermatophagoides pteronyssinus and 51 patients sensitized to Lolium perenne were investigated. Twenty-four atopic patients not sensitive to these allergens and 38 healthy subjects were also selected as controls. The basophil activation test determines the percentage of basophils which express CD63 as an activation marker, by means of flow cytometry, after in vitro stimulation with allergen, using double labelling with monoclonal antibody anti-CD63–PE and anti-IgE–FITC.Results No differences in basal values (non-activated control) were found between sensitized patients, atopic controls and healthy controls. On the other hand, sensitized patients showed a significantly higher percentage of activated basophils after stimulation by allergens in vitro than both control groups (P 〈 0.001). We found a significant correlation between skin tests and basophil activation tests (r = 0.72, P 〈 0.001). We also found a positive and significant correlation between basophil activation tests and histamine release tests (r = 0.80, P 〈 0.001), allergen-specific sulphidoleukotriene production (r = 0.7, P 〈 0.001) and the occurrence of serum allergen-specific IgE (r = 0.71, P 〈 0.001).Conclusion The basophil activation test is a highly reliable technique in the diagnosis of allergy to inhalant allergens. The sensitivity of the basophil activation test was 93.3%, and its specificity 98.4%, when using a cut-off point of 15% activated basophils as positive result.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2222.2001.01122.x
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  • 5
    Electronic Resource
    Electronic Resource
    CD63 expression by flow cytometry in the in vitro diagnosis of allergy to omeprazole (2003)
    Oxford, UK : Munksgaard International Publishers
    Allergy 58 (2003), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1398-9995.2003.00155.x
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  • 6
    Electronic Resource
    Electronic Resource
    Serum eosinophil peroxidase (EPO) levels in asthmatic patients (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 52 (1997), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Eosinophil granular proteins are a useful eosinophilic activation marker in asthmatic patients. In this study, the eosinophil peroxidase (EPO) levels were assessed in different stages of bronchial asthma, in 123 patients suffering from asthma, classified as mild (n=49), moderate (n=49), and severe (n=25), according to the International Consensus Report on Diagnosis and Treatment of Asthma, as well as in 27 healthy controls, with the aim of evaluating the importance of this protein as a severity marker in bronchial asthma, and its possible correlation with parameters such as anamnesis, respiratory function tests, and peripheral blood eosinophil count, and also with some allergologic diagnostic tests, both in vivo and in vitro. The geometric mean serum level of EPO was 9.3±11.3 ng/ml (median±SD) in controls, and 28±37.8 ng/ml in the asthmatic patients. Depending on the asthma severity, the EPO levels were 25±30.5; 29±37.1, and 41 ±47.3 ng/ml in mild, moderate, and severe asthmatics, respectively, being the significant differences between the group of patients with mild and severe asthma (P〈0.001). The number of eosinophils (eos) in peripheral blood was 157±20 eos/mm3 in the controls, 334+35 eos/mm3 in mild asthmatics, 510 ±87 eos/mm3 in moderate asthmatics, and 658±72 eos/mm3 in severe asthmatics, with significant differences between all the groups (from P〈0.05 to P〈0.001). Both the serum levels of EPO and the number of eosinophils were greater in patients with active asthma than in patients with inactive asthma (P〈0.001). Significant negative correlations (P 〈 0.001) were found between serum levels of EPO and FEY, (rs= 0.30), MEF25-75 (rs= -0.33), and MEF50 (rs= -0.34), and a good positive correlation (rs= 0.80, P〈0.001) was found between EPO levels and the number of eosinophils in peripheral blood. We also found a significant positive correlation between eosinophil number and clinical score (rs= 0.54, P〈0.001) and between EPO levels and the mentioned score (rs= 0.46, P〈0.001).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1398-9995.1997.tb01021.x
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