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  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 1131-1139 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Current-voltage characteristics, Josephson radiation spectra, and critical current versus magnetic-field dependences were measured in epitaxial, c-axis YBa2Cu3O7 step-edge Josephson junctions (SEJs) on SrTiO3 and LaAlO3 substrates with various step angles α. The results were correlated with microstructural data to determine the origin of the observed weak-link behavior. It was shown that on steps with α(approximately-greater-than)45° the SEJ is a series connection of two weak links unambiguously correlated with the occurrence of two 90° tilt grain boundaries. On steep steps, α≥70°, the boundary at the upper step edge has, on average, the (103) symmetry, while the lower one is predominantly of the basal-plane-faced (010)(001) type. Correspondingly, one link is weaker than the other, with the weaker link originating on the (010)(001) boundary. However, others have shown that analogous grain boundaries in planar (103) and biepitaxial a-axis/c-axis films do not exhibit a strong magnetic-field dependence of critical current, which is characteristic of a weak link. Hence, it is proposed that the weak-link behavior of boundaries on step edges originates from their defect structure. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 1960-1962 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have developed a microwave circuit using ten parallel-biased high-temperature superconductor Josephson junctions to demonstrate phase-locking for applications such as oscillators, mixers, and detectors. The basic cell consists of two Josephson junctions enclosed in a microstrip resonator, which provides voltage-locking and low dynamic resistance in the current–voltage characteristic. Partial synchronization of the ten junctions was observed up to 45 K and up to 1 THz. The implications of this design for power and radiation linewidth will be discussed. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 51 (1996), S. 0 
    ISSN: 1398-9995
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: In recent years, it has been possible to demonstrate mediator release into the nasal secretion after nasal allergen challenge in patients with allergic rhinitis. Using the nasal provocation model, we determined whether the mediator release was altered in immunotherapy-treated patients. Seventeen grass-pollen-allergic patients were examined under controlled, reproducible conditions. Serial challenges with increasing doses of grass pollen produced increasing numbers of clinical symptoms and release of mediators such as kinins, TAME-esterase activity, and histamine. Ten patients received a semidepot perennial grass-pollen extract for 4 years. Seven patients served as controls and did not receive immunotherapy during the observation period. Data from the group of patients receiving immunotherapy over the first year already showed a partially significant decline in the maximal mediator release after nasal allergen challenges compared to the results of pretreated challenges, whereas controls did not show any significant changes. Nasal allergen challenges after termination of 4 years' immunotherapy significantly modified the mediator release compared to pretreatment values (TAME-esterase activity P〈0.05, kinins P〈0.01, and histamine P〈0.01). Decrease of mediator release paralleled the symptom-medication scores and quantitative skin prick test. Finally, we could demonstrate a significant correlation between specific IgG increase and mediator decrease in the treated group.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 47 (1992), S. 0 
    ISSN: 1398-9995
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The aim of the present study was to compare yellow jacket venom extracts from two different companies and to compare skin prick test (SPT) with intradermal test (IDT). IDT and SPT with yellow jacket venom (ALK and Pharmacia Reless®) were performed on 54 yellow jacket allergic patients and 44 symptom-free volunteers. Venom was diluted to 300, 100, 10 and 1 μ/ml for SPT and 100, 10−1, 10−2, 10−3 and 10−4μ/ml for IDT, according to the manufacturers’instructions. Skin tests were performed on both forearms. Both extracts showed approximately the same relationship between sensitivity and specificity, but the Pharmacia Reless yellow jacket venom extract showed a 5–10 fold higher biological activity in both SPT and IDT. Thus yellow jacket venoms of ALK and Pharmacia Reless are not comparable in allergen activity at the same venom concentrations. Using extracts from the same company, SPT and IDT were comparable with regard to sensitivity and specificity at an allergen concentration 1000 times higher for SPT than for IDT.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1398-9995
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Histamine release (HR) studies were performed in 40 birch pollen-allergic patients (positive case history, positive SPT, positive birch pollen-specific serum IgE: RAST ≤ 3) with (n= 20, A) and without (n= 20, B) fruit hypersensitivity, and 10 nonatopic volunteers (C). Several fruit allergens were used and characterized by protein determination and immunoblot techniques. Dose-dependent HR (apple peel = apple pulp〉 peach = cherry) was demonstrated in both allergic groups, but to a higher extent in patients with fruit allergy (P 〈 0.01). Increased basophil sensitivity to birch pollen was found in the group with fruit allergy (P 〈 0.001). Strong correlations between the mediator response induced by several fruits indicate common allergens within the extracts. We conclude that fruit-related symptoms require not only high specific serum IgE, but a strong cellular sensitization to birch pollen allergens together with an increased cellular reactivity to fruit allergens.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 33 (1978), S. 0 
    ISSN: 1398-9995
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: In 57 patients with house dust allergy and 20 controls protease inhibitor concentrations in nasal secretions were measured before and after antigen challenge. A correlation was found between low inhibitor levels and long duration of disease. Furthermore, significant differences of inhibitor concentrations could be demonstrated between patients with strong or moderate reactions to antigen provocation, and between patients with isolated rhinitis or a combination of rhinitis and bronchial asthma. The clinical significance of the results will be discussed with special regard to different biochemical mechanisms in the pathophysiology of seasonal and perennial immediate-type rhinitis.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1398-9995
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: We investigated 10 sensitized and 10 nonsensitized workers from a pharmaceutic factory who had been exposed to powdered trypsin, chymotrypsin, bromclain, papain, amylase, and lipase. Ten nonallergic subjects served as a control group. Titrated skin prick tests (SPT), RAST, and immunoblot studies were performed with all six enzymes. SPT reactivity revealed multiple sensitizations to proteolytic enzymes, i.e., papain (specifically sensitized/total number of sensitizations: 9/10), trypsin (8/10), chymotrypsin (8/10), and bromelain (7/10) and appeared to be more frequent and more pronounced than sensitizations to amylase (3/10) or lipase (3/10). The low molecular weight of proteolytic enzymes (20–30 kDa) and their biologic activity might facilitate mucosal penetration more easily and thus - compared to amylase and lipase - permit an immune response and induction of allergic hypersensitivity. Immunoblot studies demonstrated IgG-binding bands in both SPT-positive and -negative workers, indicating exposure to the enzymes, but not in 10 unexposed control subjects. IgE-binding bands of the enzymes were detected only in workers with a positive SPT reaction and/or a positive RAST result. IgG bands were more frequent and the IgG/IgE ratio was increased in workers without allergic complaints compared to symptomatic workers. This might indicate that high levels of specific IgG antibodies to enzymes arc associated with an immune response lacking allergic manifestations in spite of IgE-mediated sensitizations to the enzymes. Atopic subjects were at greater risk of developing IgE-mediated sensitization (7/10) and allergic symptoms to enzymes (5/7). However, even without risk of atopy, IgE-mediated hypersensitivity occurred in a few subjects (3/13) exposed to enzymes by inhalation for prolonged periods of time.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 47 (1992), S. 0 
    ISSN: 1398-9995
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Determination of specific IgE by RAST is a well-established method in the diagnosis of immediate allergic reactions. In this study, we have compared the RAST with the ImmunoCAP, a novel test system which is based on a new type of solid phase. A total of 123 sera from 111 insect venom-allergic patients (74% female) were investigated. All patients had their diagnosis confirmed on the basis of their history and skin tests with insect venom. The patients’ age showed a mean ± S of 44.2 ± 14.6 years. The total serum IgE levels ranged from 4-1712 kU/1, with a median of 108 kU/1. The results of specific IgE, as determined by RAST and CAP, showed a significantly higher sensitivity, by almost one class, with the CAP compared with the RAST system. The quotient of specific IgE to total IgE, determined with the CAP system, could not be shown to be an expression of sensitization, compared with the severity of sting reactions (Müller classification (16)). A conversion factor for vespid venom RAST to CAP was calculated from the present data by subtracting the RAST from the CAP values. The mean delta value ± SD was found to be 0.9 ± 0.65, with a range from −0.8 to 2.7 and a median of 0.9. The data clearly show the differences between RAST and CAP-RAST classes, indicating that the CAP-system has a higher sensitivity and that patients with a low level sensitization are missed by the RAST method.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 40 (1994), S. 0 
    ISSN: 1365-3083
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: A new method for the measurement of allergen-specific IgD (as-IgD) was developed by modifying the ImmunoCAP assay (Pharmacia), and amplification of the signal with a goat anti-human/rabbit antigoat detection system. The assay was sensitive enough to measure as-IgD in serum samples. The specificity of the assay was examined using inhibition tests with excess corresponding and non-corresponding allergens. For the different allergens inhibition rates between 56% (house dust mite) and 88% (cat) could be achieved. Non-corresponding allergens did not inhibit the as-IgD binding. Total IgE and allergen-specific IgE (as-IgE) was measured using the ImmunoCAP system. Total IgD was measured using a sandwich ELISA. As-IgD was measured in serum samples from 51 atopic and 2.1 non-atopic subjects, and the correlation with as-IgE was examined. As-IgD was detected in both atopies and non-atopies but at higher levels in atopies. As-IgD against birch pollen and timothy pollen allergen was found to be increased in atopies with IgE directed against these allergens compared to atopies without IgE against these allergens (P 〈0.02 and P 〈0.03). As-IgD against birch pollen allergen was higher in atopies with IgE specific to this allergen than in non-atopies (P 〈0.02). In contrast to total IgE and total IgD, significant correlations were observed between as-IgD and as-IgE against timothy pollen (r= 0.34, P 〈0.04), birch pollen (r= 0.38, P 〈0.05) and cat dander allergen (r= 0.52, P 〈0.01). The observed correlations between as-IgD and IgE suggest that IgD and IgE may be similarly regulated, and thus the measurement of as-IgD may give further insight into the regulation of IgE.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1365-2222
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background Recent studies have shown that neurotrophins are produced by and can act on several immune-inflammatory cells. The origin of circulating as well as local neurotrophins is unknown.Objectives The aim of this study was to assess whether eosinophils of allergic and non-allergic donors produce, store and release the neurotrophic factors NGF, BDNF and NT-3.Methods Eosinophils were purified by negative immunoselection (purity 〉 96%) from allergic asthmatics and non-allergic donors (25 to 53 years). The presence of mRNA for neurotrophic factors was evaluated by reverse transcription PCR. Specificity was demonstrated by cloning products and sequencing. Stored NGF, BDNF and NT-3 was demonstrated by Western-blotting and flow cytometry. Eosinophils were incubated and supernatants were collected for measurement of neurotrophic factors after cell stimulation with PAF. Neurotrophin content in eosinophil lysates was determined by ELISA.Results Eosinophils demonstrate mRNA for neurotrophins. Proteins were detectable by Western blot and FACS analysis. Neurotrophins were found in the eosinophil lysates at different amounts comparing allergic and non-allergic donors. Cell stimulation with PAF (10-8–10-5 M) after priming with GM-CSF leads to a dose-dependant release of NGF and BDNF.Conclusions Eosinophils store, produce and release NGF, BDNF and NT-3. They are a possible source of elevated neurotrophin levels found in allergy and asthma.
    Materialart: Digitale Medien
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