Biomedical subjects

Birgit Wagner

Publications and source records attributed to Birgit Wagner.

7 recordsLinked to original sources

PubMed2006

Effects of established allergen sensitization on immune and airway responses after secondary allergen sensitization.

BACKGROUND: Spreading of sensitization with clinical manifestation of allergy is often observed in atopic individuals. OBJECTIVE: To investigate the effects of an established primary allergen sensitization on immune responses and airway inflammation/reactivity on secondary allergen sensitization and airway challenges in a murine model. METHODS: Balb/c mice were primarily sensitized intraperitoneally with ovalbumin or PBS, followed by systemic sensitization and airway challenges with latex extract as a secondary, unrelated allergen. Purely sham-sensitized animals were included as controls. In a second set of experiments, the primary and secondary allergens were switched. RESULTS: Sensitization with ovalbumin before sensitization with latex resulted in increased production of total and latex-specific (Hev b 3-specific) IgE and IgG(1), and enhanced secretion of T(H)2-cytokines by spleen mononuclear cells cultured with mitogen compared with single latex-sensitized mice. Furthermore, airway challenges of double-sensitized mice (ovalbumin + latex) with latex caused a significant increase in airway reactivity compared with purely latex-sensitized and challenged animals. These effects were dependent on dosing and timing of the primary sensitization in relation to the secondary sensitization and independent of the primary allergen used. CONCLUSION: Primary sensitization boosted systemic T(H)2 immune responses and enhanced the development of airway reactivity after sensitization and airway challenges with a secondary, unrelated allergen. This effect of consecutive priming was dependent on the strength of the primary sensitization but independent of the allergen used. The results explain the increased susceptibility toward sensitization spreading in atopic individuals. CLINICAL IMPLICATIONS: Because sensitization spreading is facilitated by primary sensitization, early prevention measurements or immunotherapy should be considered at this stage of monosensitization.

Allergens↗

PubMed2006

Internet-based cognitive-behavioral therapy for complicated grief: a randomized controlled trial.

The present study investigates the efficacy of an Internet-based cognitive-behavioral therapy program for bereaved people suffering complicated grief. The program combines established methods of psychotherapy with new technology--therapists and patients communicated exclusively by e-mail. Bereaved individuals diagnosed with complicated grief (n = 55) were randomly assigned to either the treatment group or a waiting list control condition. The 5-week intervention consisted of three modules: (1) exposure to bereavement cues; (2) cognitive reappraisal; and (3) integration and restoration. The Impact of Event Scale (IES), a failure to adapt scale, and the depression and anxiety subscales of the Brief Symptom Inventory (BSI) were used to assess treatment outcomes. Participants in the treatment group (n = 26) improved significantly relative to participants in the waiting condition on symptoms of intrusion, avoidance, maladaptive behavior, and general psychopathology, and showed a large treatment effect. Follow-up results show that this improvement was maintained after 3 months.

Adaptation, Psychological↗

PubMed2005

Morphological changes of the posterior airway space after tongue base suspension.

OBJECTIVES/HYPOTHESIS: The objectives were 1) to demonstrate the efficacy of tongue base suspension with the Repose System in modifying the posterior airway space on the basis of morphological changes in the retrolingual space and 2) to determine the implications of this procedure for the treatment of obstructive sleep apnea syndrome on polysomnographic and psychometric data. STUDY DESIGN: A prospective, nonrandomized study. METHODS: Polysomnography was performed before as well as 3 and 12 months after surgery in patients undergoing tongue base suspension using the Repose System. To identify morphological changes in the posterior airway space, lateral cephalometric radiography and videoendoscopy of the pharynx were performed preoperatively and postoperatively. Twenty-eight male patients with obstructive sleep apnea syndrome were included in the study. A suspension suture anchored intraorally at the mandible was passed submucosally in the body of the tongue, with suture tightness adjusted individually. RESULTS: The posterior airway space was widened by at least 2 mm in 60% of cases. Daytime sleepiness improved subjectively in 67% of patients, and the respiratory disturbance index improved postoperatively in 55%. The correlation between posterior airway space widening and the improvements in daytime sleepiness and respiratory disturbance index was not significant. CONCLUSION: Surgical intervention in obstructive sleep apnea syndrome with the Repose System does not result in permanent anatomical change in the posterior airway space.

Bone Screws↗

PubMed2004

Expression of the B subunit of the heat-labile enterotoxin of Escherichia coli in tobacco mosaic virus-infected Nicotiana benthamiana plants and its characterization as mucosal immunogen and adjuvant.

We have produced biologically active recombinant (r) LTB, the nontoxic B subunit of heat-labile toxin (LT) of Escherichia coli in tobacco mosaic virus (TMV)-infected Nicotiana benthamiana plants. We amplified the LTB encoding sequence with its leader and introduced a hexahistidyl tag and an endoplasmic reticulum retention signal. The resulting product was ligated into a TMV-based plant viral expression vector that was used for the generation of recombinant viral RNA. Eighty-nine percent of N. benthamiana plants inoculated with the recombinant viral RNA were systemically infected as determined by anti-TMV enzyme-linked immunosorbent assay (ELISA) experiments. The rLTB monomer was identified by LT-specific as well as by histidyl-tag-specific immunoblots. rLTB from plant extracts of TMV-infected N. benthamiana leaves was purified to give 75 microg rLTB pentamers per gram fresh plant material and was capable of binding G(M)1 ganglioside. The immunogenicity of the plant-produced rLTB was tested in mice and showed that intranasal application of rLTB (15 microg per mouse) induced LTB-specific IgG1 antibodies. To prove its adjuvanticity, rLTB was intranasally co-administered with the Hevea latex allergen Hev b 3, leading to allergen-specific IgG1 and IgG2a antibody production. The fact that intranasal application of rLTB and Hev b 3 prior to systemic challenge with the allergen enhanced the Th2 responses at the humoral and cellular level indicated that rLTB promoted immune responses that were naturally induced by the antigen/allergen. In conclusion, these results indicate that the plant viral expression system is suitable for the rapid large-scale production of biologically active LTB with strong mucosal adjuvant capacity.

Adjuvants, Immunologic↗

PubMed2004

Plant virus expression systems for transient production of recombinant allergens in Nicotiana benthamiana.

In recent years, several studies have demonstrated the use of autonomously replicating plant viruses as vehicles to express a variety of therapeutic molecules of pharmaceutical interest. Plant virus vectors for expression of heterologous proteins in plants represent an attractive biotechnological tool to complement the conventional production of recombinant proteins in bacterial, fungal, or mammalian cells. Virus vectors are advantageous when high levels of gene expression are desired within a short time, although the instability of the foreign genes in the viral genome may present problems. Similar levels of foreign protein production in transgenic plants often are unattainable, in some cases because of the toxicity of the foreign protein. Now virus-based vectors are for the first time investigated as a means of producing recombinant allergens in plants. Several plant virus vectors have been developed for the expression of foreign proteins. Here, we describe the utilization of tobacco mosaic virus- and potato virus X-based vectors for the transient expression of plant allergens in Nicotiana benthamiana plants. One approach involves the inoculation of tobacco plants with infectious RNA transcribed in vitro from a cDNA copy of the recombinant viral genome. Another approach utilizes the transfection of whole plants from wounds inoculated with Agrobacterium tumefaciens containing cDNA copies of recombinant plus-sense RNA viruses.

Allergens↗

PubMed2003

Plant-based heterologous expression of Mal d 2, a thaumatin-like protein and allergen of apple (Malus domestica), and its characterization as an antifungal protein.

Mal d 2 is a thaumatin-like protein and important allergen of apple fruits that is associated with IgE-mediated symptoms in apple allergic individuals. We obtained a full-length cDNA clone of Mal d 2 from RNA isolated from ripe apple (Malus domestica cv. Golden Delicious). The cDNA's open reading frame encodes a protein of 246 amino acid residues including a signal peptide of 24 residues and two putative glycosylation sites. The deduced amino acid sequence of the mature Mal d 2 protein results in a predicted molecular mass of 23,210.9Da and a calculated pI of 4.55. Sequence comparisons and molecular modeling place Mal d 2 among those pathogenesis-related thaumatin-like proteins that contain a conserved acidic cleft. In order to ensure the correct formation of the protein's eight conserved disulfide bridges we expressed Mal d 2 in Nicotiana benthamiana plants by the use of a tobacco mosaic viral vector. Transfected N.benthamiana plants accumulated Mal d 2 to levels of at least 2% of total soluble protein. MALDI-TOF mass spectrometric analyses of the recombinant Mal d 2 and its proteolytic fragments showed that the apple-specific leader peptide was correctly cleaved off by the host plant and that the mature recombinant protein was intact and not glycosylated. Purified recombinant Mal d 2 displayed the ability to bind IgE from apple-allergic individuals equivalent to natural Mal d 2. In addition, the recombinant thaumatin-like Mal d 2 exhibited antifungal activity against Fusarium oxysporum and Penicillium expansum, implying a function in plant defense against fungal pathogens.

Allergens↗

PubMed2003

Expression of allergens in E. coli and plants--benefits and drawbacks.

Recombinant allergens are quickly becoming the reagents of choice for diagnosis and therapy of type I allergic diseases. Consequently, the different methods for the production of recombinant proteins that are available today are of great interest to allergologists. Without doubt, bacterial expression will continue to play a pivotal role. In addition, plant-based expression systems will be needed to overcome problems inherent in the E. coli systems and to allow the production of glycoallergens or allergens of more complex folding.

Allergens↗