Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pollen”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1981

Time and intensity of first pollen contacts and risk of subsequent pollen allergies.

We find that the risks of immediate hypersensitivity to grass and mugwort pollens, as measured by a skin test, are positively correlated with the intensity of the first pollen season encountered in infancy. However, only indirect measures of the intensity of the pollen seasons (weather factors and vegetative growth of grasses) were available for the regression analysis performed. The risks were also dependent on the month of birth, maximal risk for both grass and mugwort pollen sensitivity being associated with birth in April-May. The results support an earlier suggestion that pollen contacts during the first 6 months of life increase the risk of pollen allergy for 20 years or more. We estimate that the elimination of early pollen contacts could have reduced the prevalence of immediate hypersensitivity to grass and mugwort pollens by approximately 20% each in the age group 0-19 years.

Adolescent↗
PubMed1987

Nasal challenge with pollen grains, skin-prick tests and specific IgE in patients with grass pollen allergy.

Nasal challenges with pollen grains are as close as possible to natural pollen exposure, but they are not well documented in grass pollen allergy. Forty-four grass pollen allergic patients and ten non-allergic volunteers were tested by means of nasal challenge, quantitative skin-prick tests with a standardized orchard grass pollen extract and serum-specific IgE. Nasal challenges were performed with lactose and increasing concentrations of orchard grass pollen grains (15-3645 grains, three-fold increase). The test was considered to be positive when a symptom score over 5 was obtained, since this score had been previously correlated with the release of PGD2 in nasal secretions. All control subjects and 3/44 patients had a negative challenge. The number of orchard pollen grains required to elicit a positive challenge was 332 +/- 440 (range: 15-1215 grains) and the distribution was Gaussian. This number is higher than expected according to pollen calendars performed during the season, but owing to the priming effect of the nasal mucosa by allergens it is compatible to natural exposure. The correlation between nasal provocation tests and skin-prick test end-points was significant (P less than 0.005, Spearman rank test). Conversely there was no correlation between nasal challenge or skin-prick test end-point and serum-specific IgE.

Adolescent↗
PubMed1996

Serological and skin-test diagnosis of birch pollen allergy with recombinant Bet v I, the major birch pollen allergen.

BACKGROUND: Type I allergy represents a severe health problem in industrialized countries where up to 20% of the population suffer from allergic rhinitis, conjunctivitis and allergic asthma bronchiale and in severe cases from anaphylaxis, leading to death. OBJECTIVE: The aim of this study was to evaluate recombinant Bet v I, the major birch pollen allergen for in vivo and in vitro diagnosis of birch pollen allergy. METHODS: A group of 51 birch pollen allergic patients and eight non-allergic control individuals were tested for birch pollen allergy by skin-prick and intradermal testing, comparing commercial birch pollen extracts with recombinant Bet v I. Quantitative and qualitative serological testing was done with natural and recombinant allergens by radioallergosorbent test (RAST), enzyme-linked immunosorbent assay (ELISA) and immunoblotting. RESULTS: Recombinant Bet v I allowed accurate in vivo and in vitro diagnosis of tree pollen allergy in 49/51 patients tested. No false positive results were obtained in any in vitro assay system (ELISA, Western blot) or by skin testing (skin-prick, intradermal test) with recombinant Bet v I. CONCLUSION: Our results document that recombinant Bet v I produced in bacterial expression systems allows accurate in vitro and in vivo diagnosis of birch pollen allergy in > 95% of birch pollen allergic patients.

Adult↗
PubMed1991

Pollen sensitization and allergy in children depend on the pollen load.

We investigated the influence of grass and birch pollen load on specific IgE response, skin prick test reactivity, and manifest allergic disorders of the eyes and respiratory tract. The study population was two groups of 200 children each, matched in sex and age, who were domiciled in areas with high and low pollen load, respectively. In the children from the area with high pollen load, the grass pollen load was 1.7 times higher than in the other and only specific IgE to grass pollen was found to be present more frequently (23.5% as against 12.5%; P less than 0.01). In the same area, the birch pollen load was 2.8 times higher, which caused specific IgE in 10.5% as against 3.5% of the other group (P less than 0.01) as well as positive skin prick test in 9.0% as against 3.5% (P less than 0.05). Reports of subjective complaints were rare among the group with high pollen load but the total number did not amount to a statistically significant increase. There was no difference between the two groups concerning sensitization and allergy to house dust mite. This suggests that the influence of the pollen load is strongest on the development of specific IgE, and less on skin test reactivity and manifest allergies.

Air Pollutants↗
PubMed2004

Maternal pollen allergy may be more important than birch pollen exposure during pregnancy for atopic airway disease in the child.

In 1993 extremely high levels of birch pollen were recorded in Stockholm, Sweden. We investigated the effects of this exposure on sensitization and development of atopic airway disease in children. The aim of this study was to assess the influence of maternal birch sensitization and symptoms of pollen allergy, as well as exposure to birch pollen during pregnancy, on sensitization and development of atopic airway disease in children. A total of 387 children with atopic heredity (70% had atopic mothers) and born in Stockholm 1993 or 1994 were investigated at age 4.5-5 yr. The children were examined and skin prick tested with inhalant and food allergens. IgE-antibodies against birch pollen and recombinant birch pollen allergen were analyzed in serum. The same tests were performed on the mothers. Children of mothers with symptoms of pollen allergy more often showed symptoms of rhinoconjunctivitis at age 4.5-5, after both high dose [Odds ratio (OR) 5.3; 95% confidence interval (CI): 2.0-13.7] and low dose (OR 4.0; 95% CI: 1.5-10.9) exposure to birch pollen during pregnancy. Similar tendencies were noted for children of mothers sensitized to birch, where stronger effects were suggested in boys (OR 3.8; 95% CI: 1.3-11.5) than in girls (OR 1.2; 95% CI: 0.2-5.5) in the high-dose exposed group. For asthma symptoms and sensitization to birch in the children the results were less consistent. It may be concluded that, maternal pollen allergy seems to have a stronger influence on the development of rhinoconjunctivitis in children with a family history of atopy than the degree of allergen exposure during pregnancy.

Allergens↗
PubMed2005

Bet v 1-specific IgA increases during the pollen season but not after a single allergen challenge in children with birch pollen-induced intermittent allergic rhinitis.

Allergen-specific immunoglobulins of the Immunoglobulin A (IgA) type have been found in the nasal fluid of patients with allergic rhinitis. IgA may play a protective role, but there are also data which show that allergen-specific IgA can induce eosinophil degranulation. The aim of this study was to quantitate Bet v 1-specific IgA in relation to total IgA in the nasal fluid of children with birch pollen-induced intermittent allergic rhinitis and healthy controls, after allergen challenge and during the natural pollen season. Eosinophil cationic protein (ECP), Bet v 1-specific IgA and total IgA were analyzed in nasal fluids from 30 children with birch pollen-induced intermittent allergic rhinitis and 30 healthy controls. Samples were taken before the pollen season, after challenge with birch pollen and during the pollen season, before and after treatment with nasal steroids. During the pollen season, but not after nasal allergen challenge, Bet v 1-specific IgA increased in relation to total IgA in children with allergic rhinitis. No change was found in the healthy controls. The ratio of Bet v 1-specific IgA to total IgA increased from 0.1 x 10(-3) (median) to 0.5 x 10(-3) in the allergic children, p < 0.001. No change was seen after treatment with nasal steroids, although symptoms, ECP and eosinophils were reduced. In conclusion, allergen-specific IgA in relation to total IgA increases in nasal fluids during the pollen season in allergic children but not in healthy controls. These findings are compatible with the hypothesis that allergen-specific IgA plays a role in the allergic inflammation and further studies are needed to clarify the functional role of these allergen-specific antibodies.

Adolescent↗
PubMed1994

Modification of concentration-response curves to inhaled methacholine after the pollen season in subjects with pollen induced rhinitis.

BACKGROUND: The effect of cessation of exposure to pollen on the concentration-response curves to inhaled methacholine was investigated. METHODS: Methacholine inhalation challenges (up to 200 mg/ml) were performed in 13 non-asthmatic patients with grass and/or Parietaria pollen-induced rhinitis during the pollen season, and one and four months after it. Concentration-response curves were characterised by their PC20, position, and plateau. RESULTS: Geometric mean methacholine PC20 increased from 6.4 mg/ml during the pollen season to 28.2 mg/ml and 54.9 mg/ml one and four months after the end of season, respectively. The mean (SE) level of the plateau decreased from 30.5 (4.3%) in the pollen season to 23.3 (3.7)% and 20.1 (3.3)% one and four months after the end of pollen season, respectively. Although the methacholine concentration that produced 50% of the maximal response increased from 2.9 mg/ml to 4.3 mg/ml and 6.0 mg/ml, the differences were not significant. CONCLUSIONS: In non-asthmatic patients with pollen-induced rhinitis cessation of exposure to pollen is associated with significant modifications in the methacholine threshold value and level of plateau, and with a small shift in the concentration-response curves to the right.

Adult↗
PubMed1998

Seasonal variations in T-lymphocyte response to grass pollen allergens from pollen-allergic patients and healthy controls.

Previous studies have demonstrated the presence of grass pollen-specific T cells in grass pollen-allergic patients (GPA) as well as nonallergic subjects (NA). In order to elucidate a possible seasonal variation in proliferation and cytokine production of peripheral blood mononuclear cells (PBMC), PBMC from 13 GPA and 11 NA were stimulated with extracts of Phleum pratense and tetanus toxoid before and during two grass pollen seasons. IL-4, IL-5 and interferon-gamma were determined by ELISAs. PBMC from GPA demonstrated a decreased proliferative response to grass pollen allergens during the pollen season as compared to NA (p < 0.05), but no difference was found in the response to tetanus toxoid. Cells from GPA produced higher amounts of IL-4 and IL-5 than NA (p < 0.05) and the seasonal variation in GPA proliferation was paralleled by the grass pollen-induced production of both IL-4 and IL-5 (p < 0.05). We conclude that during the grass pollen season PBMC from GPA have a reduced ability to proliferate and to produce Th2-type cytokines. This may be due to seasonal migration of the grass pollen-specific T cells from the blood to the tissues of primary allergen exposure.

Adult↗
PubMed1985

Pollen-stigma interaction in Brassica. III. Hydration of the pollen grains.

A method is described by which the changes in shape that accompany hydration of Brassica pollen grains may be rapidly measured. Using this technique it has proved possible to chart the small amount of hydration that takes place on anthesis, in addition to the response of pollen to a range of relative humidities in vitro and in vivo. Such measurements, together with pollen transfer experiments, indicate that under normal field conditions self-pollen undergoes a brief period of hydration followed by some loss of water and that, in the course of this hydration, many pollen grains are inhibited from further growth. Raised levels of atmospheric water cause a variety of responses in self-pollen, ranging from tube growth through the pistil to the ovary, to tubes inhibited at the stigmatic surface, accompanied by the formation of callose. Surprisingly, compatible cross-pollen is also affected by high humidity, often developing extended tubes that are incapable of penetrating the stigmatic cuticle. The development of stigmatic callose is also stimulated by these tubes, as also occurs when other members of the Cruciferae are induced to germinate on Brassica stigmas by high levels of atmospheric water. This formation of callose in response to challenge by all types of pollen tube suggests models for the self-incompatibility response in Brassica that involve a direct linkage between S (incompatibility) gene products and the formation of callose may require some reexamination. Close study of the operation of the self-incompatibility system in a number of individuals has revealed all aspects of the response to be heavily dependent on the particular S genes possessed by the plant.

Brassica↗
PubMed2001

N-linked oligosaccharides of glycoproteins from Ginkgo biloba pollen, an allergenic pollen.

The pollen of Ginkgo biloba is one of the allergens that cause pollen allergy symptoms. The plant complex type N-glycans bearing beta1-2 xylose and/or alpha1-3 fucose residue(s) linked to glycoallergens have been considered to be critical epitopes in various immune reactions. In this report, the structures of N-glycans of total glycoproteins prepared from Ginkgo biloba pollens were analyzed to confirm whether such plant complex type N-glycans occur in the pollen glycoproteins. The glycoproteins were extracted by SDS-Tris buffer. N-Glycans liberated from the pollen glycoprotein mixture by hydrazinolysis were labeled with 2-aminopyridine and the resulting pyridylaminated (PA-)N-glycans were purified by a combination of size-fractionation HPLC and reversed-phase HPLC. The structures of the PA-sugar chains were analyzed by a combination of two-dimensional sugar chain mapping, IS-MS, and MS/MS. The plant complex type structures (GlcNAc2Man3Xyl1Fuc1GlcNAc2 (31%), GlcNAc2Man3Xyl1GlcNAc2 (5%), Man3Xyl1Fuc1GlcNAc2 (13%), GlcNAc1Man3Xyl1Fuc1GlcNAc2 (8%), and GlcNAc1Man3Xyl1GlcNAc2 (17%)) have been found among the N-glycans of the glycoproteins of Ginkgo biloba pollen, which might be candidates for the epitopes involved in Ginkgo pollen allergy. The remaining 26% of the total pollen N-glycans have the typical high-mannose type structures: Man8GlcNAc2 (11%) and Man6GlcNAc2 (15%).

Allergens↗
PubMed2002

Identification of an allergen related to Phl p 4, a major timothy grass pollen allergen, in pollens, vegetables, and fruits by immunogold electron microscopy.

Group 4 grass pollen allergens represent 60 kDa glycoproteins recognized by 70% of patients sensitive to these pollens. An antiserum against purified Phl p 4 from timothy grass pollen was used to investigate various pollens, fruits, and vegetables for Phl p 4-related allergens by immunogold electron microscopy. In timothy grass, mugwort, and birch pollens, allergens were located in the wall, and in timothy grass and birch pollens additionally in the cytoplasm. In peanut, apple, celery root, and carrot root, only cytoplasmic areas were labeled. Group 4-related allergens thus occur in pollens of unrelated plants and in plant food and may therefore contribute to crossreactivities in patients allergic to various pollens and plant food.

Allergens↗
PubMed2001

Immunoblot studies in birch pollen-allergic patients with and without fruit hypersensitivity: part I: antibody pattern for birch pollen extract.

About 40-70% of birch pollen allergic patients show allergic symptoms after ingesting or handling raw fruits. Several investigations have indicated a partial immunological identity between birch pollen and stone fruit. To further clarify this association, we investigated 59 patients with allergic symptoms (conjunctivitis, rhinitis, and asthma during the birch pollen season) and 18 nonatopic controls by skin prick test (SPT) and RAST with birch pollen, fresh apple, cherry, and peach as well as freshly prepared fruit extracts. According to a questionnaire dealing with symptoms after ingestion of raw fruits, the subjects were divided into groups with (35 FH+) and without (24 FH-) fruit hypersensitivity. IgE, IgG, IgG1, IgG4, IgA, and IgM binding patterns to birch pollen extracts were performed with 33 sera (12 FH+, 11 FH-, and 10 nonatopic controls) using the immunoblot-technique. Patients with FH+ expressed a significantly stronger sensitization to birch pollen than patients without FH-, as measured by RAST and SPT. Native fruits induced stronger SPT reactions than fruit extracts, and patients with FH+ showed a significantly higher skin index with all fruits and fruit extracts tested. Specific IgE, IgG, IgG1, IgG4, IgM and IgA to birch pollen extracts could be detected by immunoblot in all groups, albeit with different frequencies and intensities. From this data we conclude that fruit hypersensitivity is related more to the 17 kd and 67-85 kd than to the 26-28 kd or 36 kd protein bands of the birch pollen extract. The relationship of specific IgE > IgG > IgM to a single protein band seems to be associated with the development of symptomatic type I allergy.

Adolescent↗
PubMed2004

Airborne plane-tree (Platanus hispanica) pollen distribution in the city of Córdoba, South-western Spain, and possible implications on pollen allergy.

Plane-trees are widely grown in Spain as ornaments. This taxon releases large amounts of pollen into the air and this pollen type seems to have proved implications on pollinosis. The aim of this study was to analyse airborne Platanus pollen content in the air of C6rdoba (South-western Spain) over the last 10 years, and its distribution in different areas of the city, as well as to consider possible implications regarding pollen allergies. Results revealed that Platanus pollen concentrations have been at their highest over the last 5 years. Within the city, the lowest pollen concentrations were in Northern areas of the city. Nevertheless, concentrations high enough to be of risk are reached over the whole city. All the patients studied presented symptoms during the Platanus pollen season. We can therefore conclude that plane pollen presents a risk for the whole city although symptoms are more intense and persistent in districts with a higher number of plane-trees. Platanus allergy is a particular problem for city-dwellers, where these trees are commonly used as ornamentals.

Adolescent↗
PubMedDate not supplied

[Regional and extra-local pollen in tundra pollen samples].

Patterns of pollen spectra formation in the tundra zone of Eurasia were considered. Changes in total pollen concentration were traced in subfossil pollen samples of the tundra zone. The data on subfossil pollen spectra were used to evaluate the proportion between local and regional plus extra-local components of tundra pollen samples as well as the changes in concentration of pollen of Scots and Siberian stone pines as well as of tree and shrub birches. The diameter of dwarf birch pollen was determined in different tundra subzones of Western Siberia. The role of extra-local and regional pollen was considered for all vegetation subzones of tundra.

Pollen↗
PubMed1987

[Results of skin tests with pollen extracts of fruit trees in patients with pollen allergy].

As there have recently been increasing publications on the correlation between tree pollen allergy and fruit allergy, we asked ourselves wether this might be caused by the parallel pollen times of Fagales trees and Rosales trees in our Central European climate. Accordingly, we tested 92 patients positively suffering from Fagales tree pollen allergy with the following Rosales tree pollen extracts: apple, cherry, plum, apricote, almande. 16 out of these patients showed reactions to Fagales pollen but not to Rosales pollen. All the other 76 patients revealed reactions to both the tested pollen extracts. Since these results show our thesis to be false, we have to assume a related (minor) antigen of both tree pollen groups.

Adult↗
PubMed2004

Antisense phenotypes reveal a role for SHY, a pollen-specific leucine-rich repeat protein, in pollen tube growth.

SHY, a pollen-specific gene identified in a screen for genes upregulated at pollen germination, encodes a leucine-rich repeat (LRR) protein that is predicted to be secreted. To test if SHY plays an important role during pollen germination, we generated transgenic plants expressing an antisense (AS) copy of the SHY cDNA in pollen. Primary transformants exhibited poor seed set, but homozygous lines could be identified. In these lines, nearly all pollen tubes failed to reach the ovules; tube growth was arrested at the apex of the ovary and the pollen tubes exhibited abnormal callose deposits throughout the tube and in the tips. We show that a SHY::eGFP fusion protein is targeted to the cell wall. The structure of the SHY protein is nearly identical to other extracellular matrix glycoproteins that are composed of LRRs, such as the polygalacturonase inhibitor proteins (PGIP) of plants. PGIPs may function as defense proteins by inhibiting fungal endo-polygalacturonases, but enzyme assays with extracts of AS-SHY pollen do not support such an inhibitor role for SHY. The tomato ortholog of SHY interacts with a tomato receptor kinase (LePRK2) in yeast two-hybrid and pull-down assays; this, and the AS-SHY phenotypes, suggest instead that SHY might function in a signal transduction pathway mediating pollen tube growth.

Amino Acid Sequence↗
PubMed2001

Do pollen donors with fastest-growing pollen tubes sire the best offspring in an anemophilous tree, Betula pendula (Betulaceae)?

The relationship between pollen and progeny performance has been a subject of many studies but the evidence for pollen-tube growth rate as an indicator of progeny fitness is equivocal. We used an anemophilous tree, Betula pendula, to examine the relationship between pollen-tube growth rate and seed and seedling performance. We crossed nine maternal plants with pollen from six pollen donors in a clonal B. pendula seed orchard, measured the pollen-tube growth rates for every cross, and analyzed the performance of the resulting seeds and seedlings. The only significant positive correlation was found between pollen-tube growth rate and seed mass when we controlled for seed number per inflorescence. Using seed mass as a covariate, we found that only maternal parent had a significant effect on the number of seeds per inflorescence, the percentage of germinable and embryonic seeds, and early seedling growth. Both maternal and paternal parents had significant effects on seedling height after 85 d of growth. These results are in concordance with the general view that maternal effects are usually most apparent in seed characters and during early plant growth. This study does not provide strong evidence for the theory of pollen-tube growth rate as an indicator of progeny quality.

Journal Article↗
PubMed2006

Proteomics identification of differentially expressed proteins associated with pollen germination and tube growth reveals characteristics of germinated Oryza sativa pollen.

Mature pollen from most plant species is metabolically quiescent; however, after pollination, it germinates quickly and gives rise to a pollen tube to transport sperms into the embryo sac. Because methods for collecting a large amount of in vitro germinated pollen grains for transcriptomics and proteomics studies from model plants of Arabidopsis and rice are not available, molecular information about the germination developmental process is lacking. Here we describe a method for obtaining a large quantity of in vitro germinating rice pollen for proteomics study. Two-dimensional electrophoresis of approximately 2300 protein spots revealed 186 that were differentially expressed in mature and germinated pollen. Most showed a changed level of expression, and only 66 appeared to be specific to developmental stages. Furthermore 160 differentially expressed protein spots were identified on mass spectrometry to match 120 diverse protein species. These proteins involve different cellular and metabolic processes with obvious functional skew toward wall metabolism, protein synthesis and degradation, cytoskeleton dynamics, and carbohydrate/energy metabolism. Wall metabolism-related proteins are prominently featured in the differentially expressed proteins and the pollen proteome as compared with rice sporophytic proteomes. Our study also revealed multiple isoforms and differential expression patterns between isoforms of a protein. These results provide novel insights into pollen function specialization.

Electrophoresis, Gel, Two-Dimensional↗