Observational study of respiratory syncytial virus-associated hospitalizations and use of palivizumab in premature infants aged 29-32 weeks.
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Antibodies, Monoclonal↗
Biomedical subjects
W D Müller
Publications and source records attributed to W D Müller.
Procalcitonin and interleukin-6 in the diagnosis of early-onset sepsis of the neonate.
UNLABELLED: The reliability of procalcitonin (PCT) and interleukin-6 (IL-6) was determined and compared with that of C-reactive protein (CRP) in the diagnosis of early-onset sepsis of the neonate within the first 12 h of life. ROC analysis of values of 41 neonates with blood-cultures-positive and clinical sepsis compared with those of 27 uninfected neonates revealed sensitivities for PCT (> or = 6 ng/mL), IL-6 (> or = 60 pg/mL), and CRP (> or = 2.5 mg/L) of 77%, 54%, and 69% and specificities of 91%, 100% and 96%, respectively. Sensitivity of CRP at > or = 8 mg/L was 49% (p = 0.012 compared to PCT). CONCLUSION: PCT was the most sensitive diagnostic parameter in the diagnosis of early-onset sepsis within 12 h of life.
Birth Weight↗
[Blueberry muffin baby: the pathogenesis of cutaneous extramedullary hematopoiesis].
Two neonates exhibited the clinical picture of the "blueberry muffin baby" at delivery. The integument manifested petechiae and purpuric magenta-colored macules, papules, and plaques, as well as blueberry-colored ecchymoses. These findings led to the diagnosis of a connatal cytomegalovirus infection and fetal erythroblastosis, respectively. The hemorrhagic-purpuric looking skin lesions reflected extramedullary hematopoiesis with ultrastructural study disclosing evidence of both erythro- and granulopoietic lineage. For the first time, we were able to demonstrate that complexes of red cells in various stages of maturation can occur in the skin, similarly to the erythroblastic islands of the bone marrow. In the pathogenesis of extramedullary hematopoiesis, mechanisms underlying the reconstitution of blood cells must be considered. These may reactivate hematopoiesis in organs where it previously occurred in embryonic and fetal life. Possible causative factors may be great compensatory demand, deficient replacement, or loss or dysfunction of corpuscular blood elements. This would explain the occurrence of this disease entity in conjunction with etiologically completely heterogeneous systemic diseases.
Cytomegalovirus Infections↗
Plaque formation on surface modified dental implants. An in vitro study.
Bacterial adhesion on titanium implant surfaces has a strong influence on healing and long-term outcome of dental implants. Parameters like surface roughness and chemical composition of the implant surface were found to have a significant impact on plaque formation. The purpose of this study was to evaluate the influence of two physical hard coatings on bacterial adhesion in comparison with control surfaces of equivalent roughness. Two members of the oral microflora, Streptococcus mutans and Streptococcus sanguis were used. Commercially pure titanium discs were modified using four different surface treatments: physical vapour deposition (PVD) with either titanium nitride (TiN) or zirconium nitride (ZrN), thermal oxidation and structuring with laser radiation. Polished titanium surfaces were used as controls. Surface topography was examined by SEM and estimation of surface roughness was done using a contact stylus profilometer. Contact angle measurements were carried out to calculate surface energy. Titanium discs were incubated in the respective bacterial cell suspension for one hour and single colonies formed by adhering bacteria were counted by fluorescence microscopy. Contact angle measurements showed no significant differences between the surface modifications. The surface roughness (Ra) of all surfaces examined was between 0.14 and 1.00 microm. A significant reduction of the number of adherent bacteria was observed on inherently stable titanium hard materials such as TiN and ZrN and thermically oxidated titanium surfaces compared to polished titanium. In conclusion, physical modification of titanium implant surfaces such as coating with TiN or ZrN may reduce bacterial adherence and hence improve clinical results.
Bacterial Adhesion↗
Scanning electron microscopical analysis of laser-treated titanium implant surfaces--a comparative study.
Design and surface qualities of titanium implants are of vital importance for long-term stability following implantation. Four different implant surfaces treated individually were analyzed with special attention focused on laser surface treatment. Surfaces with machine roughness, titanium spray coating, treated by aluminum oxide and treated by laser were examined individually. Evaluation of the surface was carried out by electron microscope examination and mechanical profilometry. The EDS analysis determined the degree of contamination of the implant surface. Electron microscope examination showed that the titanium plasma spray as well as the laser-treated implants have optimum surface qualities: a secondary and tertiary structure with micro-roughness of 10 mm and roughness ranging from 0.5 to 4 mm. The least contamination was found for machine rough surfaces as well as those treated by laser. The other implants showed contamination corresponding to the method of surface treatment. In summary the optimal surface structure with the least contamination was found for the laser-treated titanium surface. Similar surface purity was found for the machine rough surfaces. An optimal structure was also achieved by the titanium plasma spray method, however, at the cost of surface purity.
Aluminum Oxide↗
"Allergen engineering": variants of the timothy grass pollen allergen Phl p 5b with reduced IgE-binding capacity but conserved T cell reactivity.
One problem of conventional allergen-specific immunotherapy is the risk of anaphylactic reactions. A new approach to make immunotherapy safer and more efficient might be the application of engineered allergens with reduced IgE-binding capacity but retained T cell reactivity. Using overlapping dodeca-peptides, the dominant T cell epitopes of the timothy grass pollen allergen Phl p 5b were identified. By site-directed mutagenesis outside these regions, point and deletion mutants were generated. Allergen variants were analyzed for IgE-binding capacity with sera of different grass pollen allergic patients by Western blotting, Dot blotting, and EAST inhibition test, and for histamine releasing capacity with peripheral blood basophils from different patients. The deletion mutants revealed significantly reduced IgE reactivity and histamine releasing capacity, compared with the wild-type Phl p 5b. Furthermore, in vivo skin prick tests showed that the deletion mutants had a significantly lower potency to induce cutaneous reactions than the wild-type Phl p 5b. On the other hand, T cell clones and T cell lines from different allergic patients showed comparable proliferation after stimulation with allergen variants and wild-type Phl p 5b. Considering their reduced anaphylactogenic potential together with their conserved T cell reactivity, the engineered allergens could be important tools for efficient and safe allergen-specific immunotherapy.
Allergens↗
In situ localization of a high molecular weight cross-reactive allergen in pollen and plant-derived food by immunogold electron microscopy.
BACKGROUND: A high molecular weight (60 kd) allergen has been recently identified as a cross-reactive moiety in pollen and plant-derived food. While the cross-reactive allergen has been characterized by immunochemical techniques, little is known concerning its biologic properties. OBJECTIVE: In this investigation we studied the in situ localization of the 60 kd cross-reactive allergen in tree, grass, and weed pollen, as well as in plant-derived food (apple and celery). METHODS: A monoclonal antibody (3A4) that was raised against the major mugwort pollen allergen, Art v 1, was used to demonstrate the presence of related allergens in nitrocellulose-blotted pollen and plant-food extracts. The tissue localization of the cross-reactive allergen was investigated by immunogold electron microscopy. RESULTS: Monoclonal antibody 3A4 recognized IgE epitopes of the 60 kd mugwort allergen and cross-reacted with moieties of comparable molecular weights in birch and timothy grass pollen, as well as in apple and celery extracts. In pollen and plant-derived food the allergen could be localized intracellularly in ribosome-rich areas in the mitochondria and the nucleus. No labeling was observed in the pollen or cell walls or in organelles that are engaged in storage (e.g., starch granules and lipid particles). CONCLUSION: Tree, grass, and weed pollen, as well as plant-derived foods, contain a high molecular weight Art v 1-cross-reactive allergen that maps to similar cell compartments.
Allergens↗
Detection and quantification of group 4 allergens in grass pollen extracts using monoclonal antibodies.
BACKGROUND: Grass pollen extracts are complex mixtures consisting of different major allergenic and non-allergenic components. Phl p 4 is an important allergen, because more than 75% of grass pollen allergic patients produce specific IgE antibodies against group 4 allergens. OBJECTIVE: This study was designed to investigate the specificity of monoclonal antibodies (MoAbs) produced against Phl p 4 and to verify the presence of group 4-like proteins in different grass pollen. Furthermore the usefulness of MoAbs for quantification of group 4 allergens was studied. METHODS: Group 4 analogues were investigated by immunoblotting and ELISA inhibition using three MoAbs. The specificity of antibodies was studied using isolated group 1 and group 5 allergens. Quantification of group 4 allergen was achieved by a two-site solid-phase ELISA. Phl p 4 was purified from whole pollen extract by chromatographic or electrophoretic techniques and used as standard. RESULTS: The MoAbs studied bound strongly to proteins from timothy grass pollen extract at a mw of 55 kDa and a pI of 9.0-9.3. Phl p 4 homologes with similar mw were detected in Dactylis glomerata, Festuca pratensis, Holcus lanatus, Poa pratensis, Lolium perenne. Epitope mapping showed that all three MoAb recognized unrelated regions on Phl p 4. A two-site binding ELISA using MoAbs was developed for determination of Phl p 4 in Phleum pratense extracts. The method was able to evaluate group 4 in mass units with a working range between 150 and 2000 ng/mL. The absolute amounts of group 4 in extracts of several grasses varied considerably but was always-less than 1% of the total protein. CONCLUSION: Group 4 homologes are present in the various grass extracts but to different extents. The group 4 ELISA could be very useful as a additional tool for providing information concerning the composition of grass pollen extracts.
Allergens↗
Mapping of T-cell epitopes of Phl p 5: evidence for crossreacting and non-crossreacting T-cell epitopes within Phl p 5 isoallergens.
BACKGROUND: Group 5 allergens represent major grass pollen allergens because of their high sensitization indices. The identification of T-cell epitopes of these allergens is a prerequisite for the design of immunotherapeutic strategies based on peptide vaccination or modified allergens with conserved T-cell epitopes. OBJECTIVE: This study was undertaken to determine T-cell epitopes on Phl p 5 major pollen allergen of timothy grass (Phleumn pratense). METHODS: T-cell lines (TCLs) and T-cell clones (TCCs), specific to Phl p 5, were established from the peripheral blood of 18 patients allergic to grass pollen. All TCCs were mapped for epitope specificities using 178 overlapping dodecapeptides representing the primary structures of two isoforms of Phl p 5 (Phl p 5a and Phl p 5b). Phenotype and cytokine production profiles of TCCs were tested. Selected TCCs were analysed for HLA class II restriction. RESULTS: A total of 82 TCCs were isolated. All TCCs displayed the helper cell (TH) phenotype. Their reactivity with two recombinant expressed isoforms of Phl p 5a and Phl p 5b was heterogeneous. The epitope specificity of the TCCs was then revealed. Nineteen T-cell epitopes could be identified on Phl p 5. Eighty-one percent of mapped TCCs recognized three T-cell reactive regions on the Phl p 5 allergen. Some TCCs were reactive with isoepitopes presenting on Phl p 5a as well as Phl p 5b. Allergen-specific stimulation induced a TH0-like type of cytokine production in 25 of 50 TCCs. Almost all TCCs secreted high concentrations of interleukin-13. CONCLUSION: Phl p 5, a major grass pollen allergen, contains several T-cell epitopes. Some epitope regions were recognized by several patients. Epitope recognition pattern could not be correlated with special HLA class II haplotypes. T-cell stimulating isoepitopes were found at corresponding regions of Phl p 5a and Phl p 5b isoforms.
Adult↗
Novel bradykinin signalling events in PC-12 cells: stimulation of the cAMP pathway leads to cAMP-mediated translocation of protein kinase Cepsilon.
In the rat pheochromocytoma cell line PC-12, bradykinin (BK) stimulated phosphatidylinositol hydrolysis by 4-5-fold and, additionally, intracellular cAMP accumulation by approx. 1.6-fold. EC50 values for BK were 3 nM and 2 nM respectively. The BK-induced increase in cAMP accumulation was paralleled by a 1.6-fold increase in protein kinase A (PKA) activity. The time course of BK-stimulated inositol phosphate formation was rapid (t1/2<1 min), whereas the BK-induced cAMP accumulation was lagging (t1/2 approx. 6 min). The effect of BK on the cAMP pathway was independent of pertussis toxin, excluding an indirect stimulation of adenylate cyclase via betagamma-complexes from Gi or Go proteins. Two different protein kinase C (PKC) inhibitors, bisindolylmaleimide and Ro 31-820, failed to prevent BK-induced cAMP accumulation, and exclude PKC as mediator of BK action on adenylate cyclase. In contrast, the stimulatory effect of BK on cAMP accumulation was completely abolished by two calmodulin antagonists, chlorpromazine and ophiobolin, suggesting an indirect, Ca2+/calmodulin-mediated effect of BK on the cAMP pathway. In addition, exposure of PC-12 cells to BK resulted in a translocation of the PKC isoforms alpha, delta, epsilon and zeta displaying different kinetics. The BK-induced translocations of the PCDs alpha and delta were rapid and biphasic, whereas the PKCs epsilon and zeta revealed a slower and slightly transient translocation in response to BK. The BK-elicited translocation of PKCepsilon, but not that of the PKCs alpha, delta and zeta, was prevented by two different inhibitors of adenylate cyclase, 2',5'-dideoxyadenosine and MDL-12,330A, as well as the PKA inhibitor adenosine 3':5'-monophosphothioate. These findings suggest that the BK-induced translocation of novel (n)PKCepsilon is mediated via the cAMP pathway. Since nPKCepsilon appears to regulate neurite outgrowth in PC-12 cells [Hundke, McMahon, Dadgar and Messing (1995) J. Biol. Chem. 270, 30134-30140] our results provide evidence for a novel signalling mechanism that might be involved in BK-induced neuronal differentiation of PC-12 cels.
Adenylate Cyclase Toxin↗
[Improving the design of an alloplastic epithelialized tracheal prosthesis].
Replacement of the tracheal conduit remains an unresolved problem. The microporous material expanded polytetrafluorethylene (ePTFE) is suitable for tracheal reconstruction. The aim of our study was to improve the limited mechanical properties of this material by incorporating reinforcement elements and to examine the influence of these elements on host incorporation and epithelialization. In so dours ePTFE prostheses were reinforced with lonomer cement and porous high density polyethylene (pHDPE) rings and implanted into the neck muscle of miniature pigs. One of these prostheses was epithelialized by a cell seeding technique and was thus placed into a tracheal defect. Results were examined grossly by endoscopy and than by light and scanning electron microscopy. The shapes of both types of prostheses showed a high stability. The reinforcement elements did not impair bioincorporation or the ability to epithelialize. In vivo interposition of an incorporated and epithelialized prosthesis to a host led to cell differentiation. The improved biomechanical properties of the prostheses waid and the reproducible formation of epitheliums are important advances in the solution of effectively correcting tracheal defects.
Animals↗
Application of reversed-phase high-performance liquid chromatography in the purification of major allergens from grass pollen.
Group 1 and 5 allergens of different grasses possess similar physicochemical parameters (molecular weight, pI) and therefore separation with conventional chromatographic methods (gel filtration, ion exchange chromatography) is difficult or impossible to achieve. In this paper we describe the isolation of biologically active group 1 and 5 allergens from extracts of Lolium perenne and Phleum pratense by means of reverse phase chromatography on HPLC. The chromatograms showed very different retention times for group 1 (Rt 19.1-20.5 min) and group 5 (Rt 24.3-26.3 min) containing fractions. In addition, this technique is suitable for the separation of group 5 allergens into 5a and 5b subgroups and for the estimation of the amounts of allergen (groups 1 and 5) in the different extracts.
Allergens↗
Characterization of Phl p 4, a major timothy grass (Phleum pratense) pollen allergen.
BACKGROUND: Group 4 grass pollen allergens represent glycoproteins with a molecular weight of 50 to 60 kd, which are present in many grass species. Almost 75% of patients allergic to grass pollen display IgE reactivity to group 4 allergens, which hence can be regarded as major grass pollen allergens. OBJECTIVE: In this study attempts were made to obtain information regarding the immunologic properties, localization, and occurrence of Phl p 4 and related allergens. METHODS: Phl p 4 was detected in timothy grass pollen extracts by immunoblotting with serum IgE and monoclonal antibodies and was localized in pollen by immunoelectron microscopy. A peptide sequence from Phl p 4 was obtained by amino acid sequencing. The resistance of Phl p 4 against trypsin was analyzed after trypsin treatment of timothy grass pollen extracts with serum IgE and monoclonal antibodies. Cross-reactivities between Phl p 4 and Amb a 1, the major allergen of ragweed, were studied by using monoclonal antibodies and by IgE- inhibition studies. RESULTS: Phl p 4 was characterized as a trypsin-resistant major timothy grass pollen allergen. By immunoelectron microscopy Phl p 4 was localized in the exine, cytoplasm, and amyloplast of timothy grass pollen. significant sequence similarities of a Phl p 4 10 amino acid peptide with Amb a 1, the major ragweed allergen, could be found. The immunologic similarity of Phl p 4 and Amb a 1 was confirmed by cross-reactivity of monoclonal antibodies and patients' IgE. CONCLUSION: Phl p 4 represents a trypsin-resistant major timothy grass pollen allergen with immunologic similarities to the major ragweed allergen Amb a 1 and therefore must be considered an important cross-reactive component in grass pollen and weed pollen allergy.
Allergens↗
Identification of a 60 kd cross-reactive allergen in pollen and plant-derived food.
BACKGROUND: Cross-reactive IgE antibodies were found to be responsible for allergic reactions in patients allergic to pollen on ingestion of food (oral allergy syndrome). So far, the major birch pollen allergen Bet v 1 and birch profilin (Bet v 2) were identified as relevant cross-reactive allergens. OBJECTIVE: In this study we attempted to identify additional cross-reactive plant allergens, which could be responsible for food intolerance in patients allergic to pollen. METHODS: Monoclonal antibodies specific for the major mugwort pollen allergen, Art v 1, representing a 60 kd glycoprotein, were used to detect cross-reactive allergens in other pollens and plant-derived food. The amino acid compositions of the cross-reactive structures were determined, and their resistance against trypsin treatment was investigated. In addition, IgE immunoblot inhibitions were done with the 60 kd mugwort pollen allergen. RESULTS: Monoclonal antibodies specific for the major mugwort pollen allergen, Art v 1, cross-reacted with proteins of comparable molecular weight in fruit and vegetables. Preadsorption of patients' sera with the 60 kd mugwort allergen led to a reduction of IgE binding to components of a similar molecular weight present in different pollen (birch, timothy grass), fruit (apple, peanuts), and vegetable (celery) extracts and reduced IgE binding to apple, kiwi, and celery as determined by RAST inhibitions. CONCLUSION: A cross-reactive plant panallergen, possibly identical to the major mugwort pollen allergen, Art v 1, is described. The allergen represents a protein of approximately 60 kd present in various pollen and plant foods; which is distinct from Bet v 1 and profilin and hence may represent a novel cross-reactive allergen in the oral allergy syndrome.
Allergens↗
Group 5 allergens of timothy grass (Phl p 5) bear cross-reacting T cell epitopes with group 1 allergens of rye grass (Lol p 1).
Selected human T cell clones reactive with group 5 allergens of timothy grass (Phl p 5) were cross-stimulated in specific proliferation assays with group 1 allergens of rye grass (Lol p 1). Such interspecies cross-reactivities result obviously from structural motifs presented on defined Phl p 5 fragments as shown with recombinant Phl p 5 products.
Allergens↗
Purification and characterization of the major allergen from apple and its allergenic cross-reactivity with Bet v 1.
The major allergen from apple extract was concentrated by anion exchange chromatography and further purified by reverse-phase HPLC. A distinct peak with a high degree of homogeneity was obtained. The isolated protein has a MW of 18 kD and specific IgE-binding capacity (immunoblotting, IgE-binding inhibition). N-terminal amino acid analyses of the allergen allowed 37 cleavages and showed 67.6% identity to Bet v 1, the major allergen of birch pollen. Enzyme immunoassay inhibition studies with serum of birch/apple-allergic patients showed that besides cross-reacting structures to Bet v 1, apple-specific IgE antibodies could exist. Monoclonal antibodies (mAbs) were raised against the 18-kD allergen from apple and characterized by means of immunoblotting and ELISA. Only three of the eight studied mAbs reacted with Bet v 1.
Allergens↗
A two-site monoclonal antibody ELISA for the quantification of group V allergens in grass extracts.
A two-site solid-phase enzymimmunoassay was used for the quantification of group V allergen in grass pollen extracts in mass units. The assay is based on the monoclonal antibodies (MoAbs), 1D11 and 3B2 which recognize different epitopes on the standard Phl p V. The MoAb-ELISA is very sensitive (15-100 ng/ml Phl p V) and highly specific for group V allergens. Six pollen extracts of different grasses demonstrated parallel binding curves. The group V content ranged between 73 and 673 micrograms/ml in the extracts. The International Standard of Phleum pratense (IS 82/520) contains 400 micrograms/ml Phl p V. A good correlation was observed between the group V content and RAST inhibition, with the exception of Poa pratensis.
Allergens↗
Analysis of human T cell clones reactive with group V grass pollen allergens.
Twenty-seven T cell clones (TCC) reactive with group V allergens of Phleum pratense (Phlp V) were established from the peripheral blood of 3 patients allergic to grass pollen. Twenty-four TCC showed the helper cell phenotype CD3+, CD4+, CD8-; the remaining clones were CD3+CD4-CD8+. T cell recognition of Phlp V was exclusively HLA-DR restricted. Many of the Phlp V reactive TCC (19 of 27; 70%) were stimulated additionally by other group V allergens isolated from Lolium perenne, Poa pratensis, and Dactylis glomerata. These data indicate the existence of cross-reacting T cell epitopes among group V allergens of different grasses. The Phlp V triggered cytokine production demonstrated in 13 out of 24 CD4+ TCC a Th2-like pattern (high interleukin 4/gamma-interferon ratios) suggesting group V allergens as important targets of grass pollen specific IgE.
Adult↗