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H Breiteneder

Publications and source records attributed to H Breiteneder.

At least 73 records · Page 4Linked to original sources
PubMed1998

Characterization of allergens in plant-derived spices: Apiaceae spices, pepper (Piperaceae), and paprika (bell peppers, Solanaceae).

Allergens in spices from the botanic families Apiaceae, Piperaceae, and Solanaceae were characterized. IgE-immunoblotting and IgE-inhibition experiments revealed broad cross-reactivity among spices and to pollen-derived proteins. Moreover, monoclonal antibodies raised against cross-reactive pollen allergens (profilin, Bet v 1) detected homologous proteins in almost every spice source analyzed. It can be concluded that allergy to spices rarely represents an autonomous sensitization, but is rather a consequence of pollen allergy on the basis of immunologic cross-reactivity.

Allergens↗
PubMed1998

Biochemical characterization of Pru a 2, a 23-kD thaumatin-like protein representing a potential major allergen in cherry (Prunus avium).

BACKGROUND: The prevalence of allergy to fruits and vegetables increased with pollinosis over the last 10 years. So far, clusters of hypersensitivity have been established and corroborated by the molecular characterization of individual cross-reacting allergens. Several case studies demonstrated the existence of allergic reactions to fruits of the subfamily Prunoideae (apricots, cherries, plums and peaches). Here, we present the characterization of a major allergen in cherry. METHODS: Characterization was performed using IgE immunoblotting and immunoblot inhibition, N-terminal sequencing, mass spectroscopy analysis and PCR-based cDNA cloning. RESULTS: A 23-kD protein was identified as IgE-binding component. As all cherry-extract-reactive sera displayed IgE-binding to this band, it was designated a major allergen from Prunus avium (Pru a 2). Sequencing the corresponding cDNA identified Pru a 2 as a thaumatin-like protein belonging to the group 5 of pathogenesis-related proteins. CONCLUSIONS: A thaumatin-like protein in cherry has been identified as a major allergen (Pru a 2). Homologous proteins from the thaumatin family share sequence similarities and should therefore be checked for the capability to elicit an IgE-mediated allergic reaction.

Allergens↗
PubMed1998

Molecular and immunological characteristics of latex allergens.

Natural rubber latex proteins are a well-recognized cause of type-I allergic reactions that increasingly afflict health-care workers, housekeeping personnel, and other persons using latex gloves or latex products. More than a dozen individual latex allergens have been identified of which eight have received an international nomenclature designation. To study the biochemical and immunological properties in detail, it is desirable to clone and express each of these allergens. Proteins that are involved in rubber synthesis are most likely confined to latex whereas other enzymes, such as chitinases or glucanases, are also present in fruits and may account for the symptoms observed in the latex-fruit syndrome. The available data on the molecular characterization of latex allergens presented here illustrate the importance of this research in the production of better diagnostic tests and, perhaps, tools for immunotherapy.

Allergens↗
PubMed1998

Bell peppers (Capsicum annuum) express allergens (profilin, pathogenesis-related protein P23 and Bet v 1) depending on the horticultural strain.

BACKGROUND: Little is known about the role of bell peppers in food allergy. We collected sera from 11 patients with food allergy to bell peppers to analyze bell pepper extracts for allergen composition. METHODS: Proteins of mature fruits of eight horticultural strains of bell peppers were extracted and tested with patients' sera for IgE binding and with monoclonal and polyclonal antibodies in immunoblot. RESULTS: Profilin was detected in bell pepper extracts by an anti-celery profilin antibody. It showed high IgE binding activity in all extracts, which could be inhibited by recombinant birch pollen profilin. Anti-birch pollen monoclonal antibody BIP3, directed against birch pollen proteins between 30 and 69 kD, bound to bell pepper antigens of comparable molecular weights. A homologue of the major birch pollen allergen Bet v 1 was detected in four of eight horticultural strains of bell peppers, and was shown to bind IgE in 1 of the 11 patients. A 23-kD allergen of bell peppers was shown to correspond to the 23-kD major paprika allergen by IgE absorption experiments. Its N-terminal sequence showed 100% identity to P23 from tomatoes. CONCLUSION: The appearance of profilin in all and Bet v 1 in 50% of the tested horticultural strains indicates that bell peppers have to be considered potentially dangerous for Bet v 1- and profilin-sensitized patients. Moreover, in 4 of 8 horticultural strains of bell peppers a homologue of the osmotin-like protein P23 from tomatoes is responsible for substantial IgE binding. Contact with Bet v 1 and P23 homologues in bell peppers can therefore be minimized by avoidance of the respective horticultural strains.

Adult↗
PubMed1998

Transdermal penetration of diclofenac after multiple epicutaneous administration.

OBJECTIVE: To test whether therapeutic diclofenac concentrations are attained in skeletal muscle tissue beneath the application site of an epicutaneously administered diclofenac foam formulation. METHODS: Diclofenac foam (5%) was administered epicutaneously at the thigh 80 mg/200 cm2 twice daily for a period of 7 days in healthy volunteers (n=12). On Day 8, 2 microdialysis probes were inserted into skeletal muscle tissue beneath the application site and an 80 mg dose was administered epicutaneously. Concentration versus time profiles in plasma and skeletal muscle were followed for 10 hours. RESULTS: Concentration versus time profiles were obtained for plasma and interstitial muscle fluid in all experiments. Mean Cmax in plasma was 18.75+/-4.97 ng/ml. Corresponding interstitial concentrations in skeletal muscle were significantly higher, 219.68+/-66.36 ng/ml (p=0.01). Plasma concentrations were not correlated to tissue concentrations (r=-0.08). CONCLUSION: There is significant direct penetration of diclofenac into skeletal muscle following multiple epicutaneous administration. However, the concentration attained in individual subjects is not predictable and may be strongly influenced by individual skin properties.

Administration, Cutaneous↗
PubMed1997

Genomic characterization of members of the Bet v 1 family: genes coding for allergens and pathogenesis-related proteins share intron positions.

Bet v 1, the major birch pollen allergen, is a member of a multigene family; a number of isoforms and homologous proteins from closely related species (alder, hazel and hornbeam) has been isolated and their cDNAs cloned and characterized. Genomic clones coding for Bet v 1 and homologues from apple and hazel were isolated and sequenced. Some of these clones contained intervening sequences. The exon-intron formation is highly conserved throughout this family of pathogenesis-related proteins in dicot plants and is also found in Aopr1 (Asparagus officinalis), a monocol species. Phylogenetic analysis suggested a possible common origin of the intron position in these homologous proteins at codon 62 in various families of flowering plants, including Fagaceae, Rosaceae and Apiaceae. This conserved 'proto-splice site' may point to a structure/function relationship. A conserved sequence motif (P-loop) was also found in all members of this protein family. Moreover, there is a certain degree of sequence similarity among the proteins derived from various species throughout the dicots and the only monocot examined. This fact is reflected by cross-reactivity from monoclonal and polyclonal antibodies raised against Bet v 1.

Allergens↗
PubMed1997

The effect of systemic nitric oxide-synthase inhibition on ocular fundus pulsations in man.

There is experimental evidence that endothelium derived nitric oxide is involved in the regulation of ocular vascular tone. The purpose of this study was to investigate the effects of NO-synthase inhibition by N-monomethyl-L-arginine (L-NMMA) on ocular fundus pulsations in young healthy volunteers. Three milligrams per kilograms L-NMMA were administered i.v. over 5 minutes. Protocol 1: Measurements of blood pressure, pulse rate, fundus pulsation amplitude, NO-exhalation, and cardiac output were performed at baseline and 10, 30, 60, 90, 150, and 300 minutes after L-NMMA infusion (n = 8). Fundus pulsation amplitude, which has been shown to estimate the pulsatile component of the choroidal blood flow, was recorded with a recently developed laser interferometer. Protocol 2: Measurements of blood pressure, pulse rate, fundus pulsation amplitude, NO-exhalation, and blood flow velocity in the ophthalmic artery were performed in a randomized, placebo controlled cross over study (n = 10). Ten minutes after L-NMMA administration fundus pulsation amplitude decreased by 23 +/- 2% (protocol 1) and 19 +/- 1% (protocol 2, P < 0.01 each), cardiac output by 12 +/- 2% (P < 0.01), and exhaled NO by 55 +/- 6% (protocol 1) and 41 +/- 6% (protocol 2, P < 0.01 each). All parameters returned to baseline values within the 300 minutes observation period, with a faster recovery of fundus pulsation amplitude than of cardiac output and exhaled NO. Blood pressure, pulse rate, and ophthalmic artery blood flow velocity showed only minor changes during and after administration of L-NMMA. Our results suggest that systemic NO-synthase inhibition reduces pulsatile choroidal and most likely total choroidal blood flow in humans. The recovery of vascular tone in choroidal vessels seems to be different from the cardiovascular response. Our findings indicate that reduced fundus pulsations after L-NMMA are caused by systemic factors as well as by local reactions of the choroidal vasculature.

Adult↗
PubMed1997

The potential of Betv1 homologues, a nuclear multigene family, as phylogenetic markers in flowering plants.

Betv1 homologues are a ubiquitous group of genes in flowering plants encoding a class of highly conserved defense-related proteins and containing open reading frames from 465 to 480 bp. Betv1-like genes consist of two exons interrupted by an intron of 76-359 bp, with the intron position highly conserved. The pairwise p distance ranged from 0 to 0.583 among flowering plants. Within plant families, the ranges of the p distance were 0-0.403, 0-0.253, and 0.011-0.369, for Apiaceae, Betulaceae, and Fabaceae, respectively. The most striking feature of the betv1 gene phylogeny was that the multiple sequences from each plant family formed a monophyletic group and sequences from each species were generally more similar to each other than those from other species. The almost exclusive paralogous relationships of genes from the same species suggested that the genes of the multigene family underwent strong concerted evolution. Phylogenies of Betulaceae and Fabaceae inferred from betv1 gene trees were generally congruent with those based on morphology and other molecules. Betv1 homologues constitute potential phylogenetic markers at the intrafamilial level or among closely related families in flowering plants.

Base Sequence↗
PubMed1997

High-level expression and purification of the major birch pollen allergen, Bet v 1.

Bet v 1, the single major allergen from birch pollen, shares IgE epitopes with all major tree pollen allergens from closely related species such as alder, hazel, hornbeam, beech, and European chestnut. Because of high sequence homologies among these allergens and the well-studied cross-reactivities on B cell epitopes, Bet v 1 is a representative model protein which can be used for in vitro studies. The cDNA coding for Bet v 1, the single major allergen from birch pollen, was cloned into the T7-based Escherichia coli expression system pMW 175/BL21(DE3) and synthesized as a nonfusion protein. In contrast to other E. coli systems (e.g., pKK233-2/JM105), this system produces high levels of readily extractable proteins corresponding to 5-10% of E. coli total protein, the percentage varying with culture conditions. The overall yield was 8-10 mg of purified recombinant protein per liter of culture medium. The recombinant allergen was purified by several steps, including ion-exchange and hydrophobic interaction chromatography. The purified recombinant allergen showed identical immunological properties with the respective natural counterpart. The use of recombinant allergens of high purity is expected to result in more accurate diagnostic procedures, but possibly also in a superior immunotherapy of Type I allergic diseases when compared with methods using crude allergen extracts containing various amounts of allergen concentrations.

Allergens↗
PubMed1997

Effects of antiglaucoma drugs on ocular hemodynamics in healthy volunteers.

BACKGROUND AND PURPOSE: There is evidence that ocular blood flow plays a critical role in the clinical course of glaucoma. Hence a reduction in ocular blood flow due to topical antiglaucoma treatment should be avoided. The purpose of this study was to characterize the effect of antiglaucoma drugs on ocular hemodynamics. METHODS: In a double-blind, placebo-controlled, randomized crossover study, we investigated the effects of single topical doses of five beta-blocking agents (befunolol, betaxolol, levobunolol, metipranolol, and timolol), two adrenergic agents (clonidine and dipivefrin [INN, dipivefrine]), and a parasympathomimetic agent (pilocarpine) on ocular and systemic hemodynamics in healthy subjects (n = 10). Fundus pulsation amplitudes in the macula and the optic disc were measured to characterize pulsatile choroidal and optic disc blood flow, respectively. Moreover, central retinal and ophthalmic artery blood flow velocities were measured by Doppler ultrasound. RESULTS: Befunolol, metipranolol, timolol, clonidine, and dipivefrin reduced fundus pulsations in the macula and the optic disc (-9% to -14% versus baseline). In contrast, betaxolol, levobunolol, and pilocarpine had no effect on fundus pulsations. Antiglaucoma drugs had no effect on either blood flow velocities in the central retinal or the ophthalmic artery or systemic hemodynamics. CONCLUSIONS: Our results indicate that befunolol, metipranolol, timolol, clonidine, and dipivefrin reduce choroidal and optic disc blood flow. This could be caused by drug diffusion to the choroid, which may cause vasoconstriction. Ocular blood flow reduction was not observed with betaxolol, levobunolol, or pilocarpine. The lack of effect of all drugs under study on central retinal blood flow velocity might partially be the result of autoregulative mechanisms. Because optic nerve head blood flow likely plays a critical role in the clinical course of glaucoma, the use of antiglaucoma drugs, which reduce blood flow, should be reconsidered.

Adrenergic Agents↗
PubMed1997

Recombinant Bet v 1, the major birch pollen allergen, induces hypersensitivity reactions equal to those induced by natural Bet v 1 in the airways of patients allergic to tree pollen.

BACKGROUND: Atopic allergens produced by recombinant DNA methods are promising tools for diagnosis and therapy of Type I allergy. To evaluate the immunologic properties of these molecules, it is necessary to compare them with natural allergens in vitro and in vivo. OBJECTIVE: The study was carried out to determine whether the potency of recombinant Bet v 1 (rBet v 1) is comparable to that of natural Bet v 1 (nBet v 1) in inducing allergic reactions in the nose and bronchi. METHODS: Thirteen patients allergic to birch pollen with bronchial asthma and/or rhinitis were investigated. Skin prick tests and nasal and bronchial challenges were performed with rBet v 1 and nBet v 1. RESULTS: In patients allergic to birch pollen, both allergens induced comparable skin reactions. In subjects with rhinitis rBet v 1 was equally potent in inducing nasal reactions (mean PD(+60)NR +/- SD, 10.48 +/- 17.42 microg vs 7.98 +/- 8.9 microg, p > 0.05). In patients with asthma, rBet v 1 was equally potent in inducing bronchial reactions (PD20 FEV1, 0.81 +/- 1.74 microg vs 0.62 +/- 1.44 microg, p > 0.05) as nBet v 1. CONCLUSION: No significant differences were observed between natural and recombinant allergen. We conclude that allergens produced by recombinant techniques can induce typical allergic reactions in important target organs of Type I allergy: the nose and bronchi.

Adult↗
PubMed1997

Cell surface characterization of T lymphocytes and allergen-specific T cell clones: correlation of CD26 expression with T(H1) subsets.

To evaluate the possibility of using surface molecules as markers for human T helper cell subsets, we studied the expression of surface molecules on T cell clones (TCCs) specific for the major birch pollen allergen, Bet v 1. No difference in the expression of the respective receptors for interferon-gamma (IFN-gamma), IL-4, IL-6, or IL-10 could be detected on T(H) subsets, nor did CD25 expression (IL-2R alpha-chain) differ significantly. However, high expression of CD26 antigen (dipeptidyl peptidase IV) correlated with a T(H1)/T(H0)-like phenotype, whereas T(H2)-like clones displayed a lower expression of CD26 antigen. Comparing cytokine production and CD26 expression simultaneously, we found a correlation between the IL-4/IFN-gamma ratio and the density of CD26 per cell. We could show that the amount of IL-4 secretion, and not of IFN-gamma secretion, was responsible for this correlation. To evaluate whether CD26 antigen expression is regulated by stimuli inducing a T(H1)- or T(H2)-like phenotype, peripheral blood mononuclear cells (PBMC) were cultured in the presence of IL-4, IFN-gamma, and IL-12, respectively. Incubation with IL-4 led to T cells with a T(H2)-like cytokine pattern and a significantly lower expression of CD26; IFN-gamma and IL-12 led to a T(H1) shift associated with an increased expression of CD26 on CD4+ T cells. By means of intracellular cytokine detection we analyzed expression of CD26 on CD4+ PBMC stimulated to produce IFN-gamma or IL-4 on a single cell level. All activated, cytokine-producing CD4+ T cells expressed CD26, but the increase in CD26 expression was higher in cells producing IFN-gamma. These data suggest that regulation of CD26 cell surface expression correlates with the production of T(H1)-like cytokines.

Allergens↗
PubMed1997

Characterization of angiotensin-II effects on cerebral and ocular circulation by noninvasive methods.

AIMS: The role of the renin-angiotensin-system (RAS) in the cerebral and ocular circulation is still a matter of controversy. In vitro and animal data lead to partially contradicting results. However, direct investigation of locally generated angiotensin II (Ang II) in humans is not possible in vivo. Hence, we hypothesised that it might be possible to characterize local effects of Ang II by comparing systemic and local haemodynamic parameters during exogenous Ang II infusion. METHODS: In a placebo-controlled, double-blind, two-way cross over study blood flow velocities in the middle cerebral and the ophthalmic artery and ocular fundus pulsations were measured during stepwise increasing doses of Ang II in 10 healthy subjects. Blood flow velocities were assessed by Doppler sonography, fundus pulsation amplitudes (FPA), which estimate local pulsatile ocular blood flow were measured by laser interferometry. Additionally, systemic blood pressure and pulse rate were measured. RESULTS: Ang II dose-dependently decreased resistive index (RI) and increased mean flow velocities (MFV) in both arteries. Fundus pulsation amplitude was dose-dependently decreased by Ang II, whereas mean arterial pressure (MAP) was significantly increased. Pulse pressure amplitude (PPA) was not affected by Ang II administration. There was a high degree of correlation between changes in RIs and the analogously calculated PPA/systolic blood pressure during Ang II infusion, which indicates that the changes in RI after Ang II administration can be attributed to changes in systemic haemodynamics. Calculation of total local ocular blood flow from fundus pulsation amplitudes and changes in flow pulsatility in the ophthalmic artery further argue against significant blood flow changes after Ang II administration. CONCLUSIONS: Interpretation of data from Doppler sonography and laser interferometry must be done very carefully when concomitant changes in systemic haemodynamics occur. RI cannot necessarily be taken as an index of distal vascular resistance in these cases and changes in MFV can be caused by changes in vessel diameter or in blood flow. Moreover, FPA cannot be taken as a measure of ocular blood flow if no additional data on flow pulsatility are available. The combination of our systemic and local haemodynamic data indicates that cerebral and ocular circulation are comparably insensitive to changes in local Ang II concentrations. Fundus pulsation and blood flow velocity measurements indicate that neither choroidal nor optic nerve head blood flow are significantly affected by administration of Ang II.

Adult↗
PubMed1997

Cisplatin-induced renal effects and thromboxane A2 receptor blockade.

The aim of this study was to evaluate the renal protective effect of linotroban, a thromboxane A2 receptor antagonist, in 25 patients with malignant tumours scheduled for cisplatin therapy. Cisplatin was administered 1 h after the start of a 24-h continuous infusion of linotroban or placebo. Glomerular filtration rate and effective renal plasma flow were measured. Infusions of cisplatin decreased glomerular filtration rate by 17 +/- 25 mL min-1 (P = 0.049 vs. baseline) and effective renal plasma flow by 94 +/- 150 mL min-1 (P = 0.049 vs. baseline) in the placebo group. In the linotroban group a decrease in glomerular filtration rate by 11 +/- 18 mL min-1 (P = 0.050 vs. baseline) and in effective renal plasma flow by 26 +/- 63 mL min-1 (P = 0.2 vs. baseline) was noted. However, no difference was noted between groups in response to treatment. Our findings indicate that linotroban may not be useful for prevention of cisplatin's acute nephrotoxic effects.

Adult↗
PubMed1997

Nitric oxide and ocular blood flow in patients with IDDM.

Endothelial dysfunction has been implicated in the pathogenesis of diabetic vascular disorders such as diabetic retinopathy. We hypothesized that either local endogenous nitric oxide (NO) synthesis or local reactivity to endogenous NO might be impaired in patients with IDDM and that this may contribute to the development of diabetic retinopathy. Ten otherwise healthy patients with long-standing IDDM and ten healthy control subjects were studied according to an open randomized two-way cross-over design. Subjects received intravenous infusions of either N(G)-monomethyl-L-arginine, an inhibitor of NO-synthase, or L-arginine, the precursor of NO synthesis, on two separate study days. Ocular hemodynamics were assessed by laser interferometric measurement of fundus pulsations and Doppler sonographic measurement of blood flow velocity in the ophthalmic artery. N(G)-monomethyl-L-arginine decreased fundus pulsations and blood flow velocity in the ophthalmic artery and increased blood pressure in healthy subjects. The responses to NO-synthase inhibition were significantly less in diabetic subjects. In contrast, L-arginine caused a comparable increase in fundus pulsations and decrease in blood pressure in both cohorts. These results indicate that systemic and ocular hemodynamic reactivity to NO-synthase inhibition is reduced in patients with long-standing IDDM, compared with healthy control subjects. Thus, this study indicates that either NO-synthase activity is increased or NO sensitivity is decreased in patients with IDDM and supports the concept of an involvement of the L-arginine-NO system in the pathophysiology of diabetic retinopathy.

Adult↗
PubMed1996

Single human T cells stimulated in the absence of feeder cells transcribe interleukin-2 and undergo long-term clonal growth in response to defined monoclonal antibodies and cytokine stimulation.

The two-signal model of T-cell activation postulates that T lymphocytes require at least two distinct signals for activation. This model has been established with bulk cultures of T cells in which T-cell-T-cell interaction can occur, possibly delivering further unrecognized costimulatory signals. The signal requirements of single T cells for the induction of clonal cell growth or the transcription of cytokines would best be studied in a cell cloning system in the absence of feeder cells; however, such an experimental system has not been reported so far. In this study, we report the long-term cloning of human resting peripheral blood CD4+CD45RO- T cells under feeder cell-free conditions in response to CD3 and CD28 stimulation in the presence of exogenous interleukin-2 (IL-2). Cloning efficiency ranged from 40% to 60% depending on the presence of additional cytokines IL-1 and IL-6. Single-call polymerase chain reaction showed that transcription of IL-2 occurred in cells stimulated through CD3 plus CD28 alone. T cells grown in response to CD3 plus CD28 plus IL-2 stimulation produced both IL-4 and interferon-gamma (IFN-gamma) on restimulation (Th0 cells) and could be functionally differentiated into Th1- or Th2-type cells by the addition of IFN-gamma or IL-4, respectively, during cell cloning. These data show on the single-cell level a two-signal model of T- cell activation for the transcription of IL-2. In addition, these experiments show that IFN-gamma and IL-4 exert their T-cell-differentiating effects directly on the T cell without any further need for antigen-presenting cells. Together, our experiments show the feasability of a defined long-term clonal cell culture system to study the growth and differentiation of human T lymphocytes.

Antibodies, Monoclonal↗