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At least 1,153 records · Page 64Linked to original sources
PubMed1986

Standardized extracts, trees.

Sensitization to pollen from wind-pollinated trees causes significant allergy problems during springtime. The magnitude of prevalence is comparable with and, in some areas, even higher than grass pollen allergy. The symptom periods are often prolonged by cross-reactivity among species and sometimes families as well as by simultaneous sensitivity to several trees, pollinating at different times. There is a need for standardized extracts to improve diagnostic precision and treatment efficacy. A substantial amount of immunochemical data on the allergens from Betulaceae species, particularly Betula (birches), are available. Relevant methods to quantitatively and qualitatively measure the allergens of birch pollen extracts are clearly reproducible in laboratories around the world. By international collaboration, such work has generated an IS that has been accepted by the IUIS Subcommittee on Allergen Standardization. The IS is a yardstick for authorities, manufacturers, and researchers that is carefully specified in terms of 1 major and a few intermediate allergens, and also of total biologic activity by RAST inhibition. A meaningful declaration of biologic activity in vivo is awaited. As yet, only a few clinical trials have been undertaken with standardized tree pollen extracts. These are, however, highly interesting, particularly those that now have started with an oral route of administration.

Administration, Oral↗
PubMed1986

A study on airborne allergenic pollen content in the atmosphere of Ascoli Piceno.

The results of 4 years (1981-1984) of monitoring airborne pollen concentration, using a volumetric trap, in the atmosphere of Ascoli Piceno (central Italy) are reported. Pollen production wasn't constant during the studied years, showing in 1982 and 1984 a very high concentration in comparison to 1981 and 1983. This is due to a dry period from April to June in 1982 and from June to July in 1984. We found that the most important allergenic pollen is Gramineae with a principal period of pollination occurring from April to July. After Gramineae, Parietaria plays an allergenic role frequently in association with the pollen of Olea, which is the most important allergenic pollen of all the trees in this area. From August to October we observed the pollination of mugwort, which was found in small quantities but nevertheless an offender in localized cases of pollinosis in Ascoli Piceno.

Humans↗
PubMedDate not supplied

The pollen calendar of Siena (Central Italy).

The atmospheric pollen count at Siena was carried out for 4 years (1978-1981) to determine the average quantity of airborn pollen and the families, genera or species which contribute to such pollen dispersal. The pollination period stretches from February to mid October. The highest pollination period is from May to July when the most important pollen producers are Poaceae, Urticaceae, Pinus, Quercus, Oleaceae and Castanea sativa. Also in March there are high pollen production values due to Cupressaceae, Corylaceae, Alnus and Ulmus.

Italy↗
PubMedDate not supplied

IgG4 blocking effect on the release of antigen-specific histamine.

We evaluated the biological effect of IgG4 antibodies in pollinosis. We studied the ability of IgG4 to mediate histamine release by measuring anti-IgG4 in pollinic patients without previous immunotherapy. We also evaluated the modifications that sera rich in specific IgG4 and IgG itself exert upon antigen-specific histamine release. According to our results, stimulation with anti-IgG4 did not induce histamine release, as opposed to stimulation with anti-IgE, which induced histamine release in all the cases studied. On the other hand, hyperimmune sera from pollinic subjects under immunotherapy and with high levels of specific IgG4 significantly inhibited the release of antigen-specific histamine from basophils of untreated patients. After isolating IgG4 by means of affinity chromatography, preincubation of this fraction with the allergen gave rise to a significant reduction in histamine release compared to preincubation of the antigen with normal sera.

Antigens↗
PubMedDate not supplied

Local intranasal immunotherapy with allergen in powder in atopic patients sensitive to Parietaria officinalis pollen.

Local Intranasal Immunotherapy (LII) is a new approach to the treatment of allergic rhinitis due to the pollen of Parietaria officinalis. The aim of this study was to verify the usefulness of LII and to determine the proper doses. Twenty adult patients all presenting a sensitization to the pollen of Parietaria officinalis were randomly divided into two groups: 15 received the treatment and five were the control group. Treatment started before the beginning of the pollinic season of Parietaria officinalis and continued during the season. The extract used was an active extract of macronized powder Parietaria officinalis pollen in increasing doses. Doses were determined periodically with specific nasal provocation tests. Results in the treated group compared to the control group were statistically significant if one considers the increase in threshold sensitivity in the nasal provocation test, the diminution of clinical symptomatology and the quantity of drug required to control symptoms in the treated group. The side effects were few; it was only in one case that the treatment had to be interrupted. LII for allergic rhinitis due to the pollen of Parietaria officinalis seems an effective and practicable method even during the pollinic season.

Administration, Intranasal↗
PubMed1994

[Concentration of pollen dust in the atmosphere of Poland].

The main allergic disorders of the upper airways are the airborne pollens of various plants. In order to determine the concentration of plant pollens in the atmosphere of Poland in the years 1989-1991 studies were carried out determining pollen counts in 21 locations throughout Poland. Four main periods of pollination were observed: 1) early spring (trees, shrubs); 2) late spring (trees); 3) early summer (grass, hay); 4) summer and early autumn (combined plants). In northern Poland and the mountain regions beginning of pollination is 15-20 days later than in western Poland and is seen approximately 10-15 days later than in central Poland. The Polish pollen counts were compared with the data from Netherlands and Italy.

Air Pollutants↗
PubMed1993

Temperature influence on differentiation and release of hazel pollen.

The aim of the present work was to identify the classic phenological stages, and to understand its relation to catkin differentiation and growth, and its consequences for the start of pollination. Phenological observations and an aeropalynological survey on Corylus avellana, which is an example of an economically and allergologically interesting arboreal plant, were carried out during 1991-1992. The comparison between the different phenological phases and the aeropalynological data, showed that the pollen trap recorded hazel-pollen presence in the atmosphere immediately after the pollen release from the orchard. The start of catkin elongation in late winter, after the chilling requirement has been fulfilled, could be used to indicate the beginning of heat accumulation necessary for pollination.

Air↗
PubMed1993

Comparison of gramineae and ragweed pollen counts measured by Hirst's and Cour's traps.

The aim of this study is to appreciate what conclusions may be drawn from the comparison between two different methods for pollen count determination in clinical allergology. In Lyon (France), two pollen collectors are set up in two places separated by ten kilometers, as the crow flies. The Hirst-type trap is on the roof of the Pasteur Institute in the town; the Cour's trap (French Association for Ragweed Study), is located at the meteorological station in the country at the east of the town. In the Rhône-Alpes region, pollinosis is essentially due to Poacae and Ambrosia elatior. The weekly data have been recorded during three years. The results of the two categories of herbaceous plants are not comparable, except as regards the date at which the pollen season commenced. Graminae pollination (GP) commences between 20th April and 6th of May. Ragweed pollination (RP) accurately commences 5th and 6th of August! Differences in the fluctuations of peak concentrations of GP from one trap to the other can be imputed to the collectors, the site where these are located, the method used to process the data, the herbaceous weeds themselves. RPC (the dates of the peaks) are closer and more coherent. Lastly, in allergological practice, the Jacques Dechamp's rule, to only emply with the A.F.E.D.A. trap, is a hardy aid used to predict the week of the all-important peak pollen concentrations of G and R.

Air↗
PubMed1996

[Serum eosinophil cationic protein in children with allergic and nonallergic inflammation].

Serum eosinophil cationic protein (ECP) levels increase in inflammation processes with activation of eosinophils. We studied serum ECP in (I) 32 pollinic children without symptoms, in June and October and (II) 10 children with acute asthma crisis. As control groups we included (III) 25 children sent to the hospital with suspected allergic diseases in which an IgE mediated process could be ruled out; (IV) 34 coeliac patients; (V) 15 children with cystic fibrosis and (VI) 48 normal children. The pollinic children had increased figures of ECP in June (21.2 +/- 9.2 micrograms/L) compared to normal controls (p < 0.001) and they continued to have high levels in October (13.5 +/- 9.2 micrograms/L, p < 0.05). The patients with very high ECP (> 20 micrograms/K), in spite of being asymptomatic, showed a negative correlation between ECP/peak-flow (p: 0.038). In addition, in these patients the ECP also had a negative correlation with the recovery of bronchospasm from June to October (p: 0.024). Some asthmatic children also had high ECP, but the results were too heterogeneous to draw any conclusions, possibly due to the drugs received. The ECP was independent of age and sex. It not correlated with serum IgE, nevertheless, in non-atopic patients it did correlate with blood eosinophilia (p < 0.005). In coeliac and cystic fibrosis patients, we did not find ECP to be increased. In conclusion, serum ECP increases in some allergic patients and suspected allergy, but not in all cases. It does not increase in other chronic mucosal inflammations, such as coeliac or cystic fibrosis. It correlates with bronchospasms and would have some value in predicting short-term evolution.

Adolescent↗
PubMed2026

Spatial inheritance patterns across maize ears are associated with alleles that reduce pollen fitness.

Often, more pollen grains land on recipient flowers than there are ovules to fertilize. Consequently, the haploid male gametophyte engages in post-pollination competition, one way that pollen genotype can influence inheritance. The maize (Zea mays subsp. mays L.) inflorescence (ear), with its elongated stigma and style structures (silks), has a conspicuous spatial heterogeneity, with longer silks at the base of the ear than at the apex. To evaluate the hypothesis that alleles with reduced pollen fitness influence the spatial distribution of progeny genotypes along the ear, we developed an updated phenotyping platform that maps fluorescently marked mutant (Ds-GFP) kernel phenotypes on the ear via an implementation of the Faster R-CNN machine vision model (EarVision.v2) and a statistical pipeline that evaluates the relationship between kernel position and transmission ratio (EarScape). Our dataset (1384 ears) represents 58 Ds-GFP insertion alleles. None of the 48 alleles with Mendelian inheritance showed any significant spatial trend. In contrast, 50% of alleles with a pollen-specific transmission defect (5/10) exhibited significant spatial effects. An insertional mutant of the gene encoding a putative actin-binding protein, base-to-apex gradient1* (bag1*), is associated with decreased mutant transmission at the ear base relative to the apex. Surprisingly, a mutant allele of another pollen-expressed gene (Zm00001eb236740) generates the opposite trend, decreased mutant transmission toward the ear apex; and two mutant alleles of the sperm cell attachment factor gamete expressed2 (gex2) can produce ears with transmission highest at both base and apex. We conclude that pollen fitness mutants cause unexpectedly diverse spatial patterns of progeny genotypes.

Zea mays↗
PubMed1997

Potentiation of fentanyl suppression of the jaw-opening reflex by transcranial electrical stimulation.

Stinus et al. [L. Stinus, M. Auriacombe, J. Tignol, A. Limoge, M. Le Moal, Transcranial electrical stimulation with high frequency intermittent current (Limoge's) potentiates opiate-induced analgesia: blind studies, Pain, 42 (1990) 351-363.] observed that transcranial electrical stimulation (TCES) with high-frequency intermittent current potentiated opiate-induced analgesia using the tail-flick test. In unanesthetized, chronic preparations, electrical stimulation (0.5 Hz) of the lower incisor pulp of rats elicits a short-(6 ms) and a long-latency (12-18 ms) jaw-opening reflex (JOR) without any evidence of aversive behavior [J. Azerad, F. Fuentes, I. Lendais, A. Limoge, B. Pollin, Methods for selective tooth pulp stimulation in acute and chronic preparations in rats, J. Physiol., 406 (1988) 3P.]. Fentanyl increases thresholds of both reflexes and transiently suppresses the long-latency JOR. We then decided to look at the influence of TCES on both drug-induced mean of maximal threshold variation (MMTV) and duration of JOR suppression period. These parameters have been investigated in 43 Wistar rats with or without TCES administered for 3 h before the drug injection and throughout the testing period. TCES alone has no effect. In contrast, it significantly increases the duration of the reflex suppression period (149 +/- 5% vs. control, P < 0.001) while fentanyl-increased reflex thresholds remain unchanged. The fentanyl-induced JOR suppression period returns to the control values 2 days later. When a second 3-h TCES session is delivered 2 or 4 days after the first TCES session, a similar increase of this suppression period is observed. Moreover, 2 days after a second TCES session, an increase of the duration of the fentanyl-induced JOR suppression period is systematically observed. In contrast, a 6-h TCES session never induces such effects. These results confirm a potentiating effect of TCES on opioid action and demonstrate the value of repeated TCES sessions.

Analgesics, Opioid↗
PubMed2025

Quantifying genetic and genotypic gain gaps in Eucalyptus: the hidden cost of ignoring inbreeding and dominance.

Understanding the mating system of Eucalyptus species is necessary to accurately estimate genetic parameters and improve breeding programs. Eucalyptus species often exhibit mixed mating systems, leading to complex relationships among progenies. Traditional tree breeding programs that assume a half-sibling relationship for open-pollinated (OP) trials may overestimate genetic gains by neglecting the effects of inbreeding and dominance. This study focuses on Eucalyptus pellita, a species with a mixed mating system, to quantify the impact of selfing and dominance on breeding strategies. We simulated OP trial growth data for 100 randomly selected families in a randomized complete block design, using published estimated parameters for diameter at breast height (DBH). Our analysis indicated that marker-based models, particularly those incorporating dominance effects, provide more accurate genetic parameter estimates and larger predicted genetic gains than pedigree-based models. These results reveal pronounced genetic and genotypic gain gaps when traditional models are employed, underscoring the imperative for integrating dominance-informed genomic selection strategies. Thus, our study provides essential guidance for optimizing breeding programs to sustainably enhance productivity and genetic quality in Eucalyptus plantations.

Eucalyptus↗
PubMed2024

Variable resource allocation pattern, biased sex-ratio, and extent of sexual dimorphism in subdioecious Hippophae rhamnoides.

Evolutionary maintenance of dioecy is a complex phenomenon and varies by species and underlying pathways. Also, different sexes may exhibit variable resource allocation (RA) patterns among the vegetative and reproductive functions. Such differences are reflected in the extent of sexual dimorphism. Though rarely pursued, investigation on plant species harbouring intermediate sexual phenotypes may reveal useful information on the strategy pertaining to sex-ratios and evolutionary pathways. We studied H. rhamnoides ssp. turkestanica, a subdioecious species with polygamomonoecious (PGM) plants, in western Himalaya. The species naturally inhabits a wide range of habitats ranging from river deltas to hill slopes. These attributes of the species are conducive to test the influence of abiotic factors on sexual dimorphism, and RA strategy among different sexes. The study demonstrates sexual dimorphism in vegetative and reproductive traits. The sexual dimorphism index, aligned the traits like height, number of branches, flower production, and dry-weight of flowers with males while others including fresh-weight of leaves, number of thorns, fruit production were significantly associated with females. The difference in RA pattern is more pronounced in reproductive traits of the male and female plants, while in the PGM plants the traits overlap. In general, habitat conditions did not influence either the extent of sexual dimorphism or RA pattern. However, it seems to influence secondary sex-ratio as females show their significant association with soil moisture. Our findings on sexual dimorphism and RA pattern supports attributes of wind-pollination in the species. The observed extent of sexual dimorphism in the species reiterates limited genomic differences among the sexes and the ongoing evolution of dioecy via monoecy in the species. The dynamics of RA in the species appears to be independent of resource availability in the habitats as the species grows in a resource-limited and extreme environment.

Hippophae↗
PubMed1997

Cranial shape in fruit, nectar, and exudate feeders: implications for interpreting the fossil record.

At least 29 species of fossil primates have been referred to fruit, nectar, and/or exudate feeding dietary niches. Many studies have detailed the morphological correlates of fruit feeding in comparison to insectivory and folivory. In contrast, few studies have sought to differentiate the morphological correlates of fruit feeding from those of nectar and exudate feeding. This study investigates the differences between fruit, nectar, and exudate feeders using 22 cranial and dentary shape variables representing 28 species of living marsupials, bats, and primates. Discriminant function analysis is used to investigate the differences between these dietary categories using both the complete data set and a reduced data set composed of variables that might reasonably be available from fragmentary fossil material. The success rates of post-hoc classifications are 94 and 88%, respectively. These results demonstrate that it is possible to discriminate among fruit, nectar, and exudate feeders among fossil taxa with a reasonable degree of certainty using the data and techniques outlined here. Nectar feeders exhibit a unique combination of features that are associated with reduced masticatory strength and their role as pollination agents. Exudate feeder skulls and dentaries exhibit a combination of features that reflect the high stresses encountered by the anterior dentition through bark gouging behavior. Fruit feeders are morphologically diverse, exhibiting cranial and mandibular shape values that overlap with both nectar and exudate feeders. It is suggested that this diversity reflects the variety of physical properties represented among fruits, and the tendency for individual frugivore species to specialize on particular fruits.

Animals↗
PubMed2000

Time measurement and the control of flowering in plants.

Many plants are adapted to flower at particular times of year, to ensure optimal pollination and seed maturation. In these plants flowering is controlled by environmental signals that reflect the changing seasons, particularly daylength and temperature. The response to daylength varies, so that plants isolated at higher latitudes tend to flower in response to long daylengths of spring and summer, while plants from lower latitudes avoid the extreme heat of summer by responding to short days. Such responses require a mechanism for measuring time, and the circadian clock that regulates daily rhythms in behaviour also acts as the timer in the measurement of daylength. Plants from high latitudes often also show an extreme response to temperature called vernalisation in which flowering is repressed until the plant is exposed to winter temperatures for an extended time. Genetic approaches in Arabidopsis have identified a number of genes that control vernalisation and daylength responses. These genes are described and models presented for how daylength might regulate flowering by controlling their expression by the circadian clock. BioEssays 22:38-47, 2000.

Acclimatization↗
PubMed2000

A flavonoid sulfate antigen activates human alphabeta CD8+ Th2 lymphocytes in pollen allergy.

Cellular immune responses are initiated when T lymphocytes expressing alphabeta TCR recognize peptide antigens bound to MHC molecules or, less frequently, double-stranded glycolipid antigens bound to CD1 molecules. In the allergy to Parietaria judaica, human alphabeta CD8+ Th2 lymphocytes react to a non-peptide pollinic antigen presented by B cells. The environmental allergen was purified and identified as a new flavonoid pigment: 2'-O-sulfate, 6-O-betaD-glucuronopyranosyl, 2',5,6-trihydroxy-isoflavone. Its specific recognition by alphabeta CD8+ Th2 T cells (1) depends upon an MHC- and CD1-independent presentation mediated by B cells, (2) is determined by the flavonoid carbohydrate and sulfate groups and (3) leads to positive skin prick test in allergic patients. Hence, an unusual mode of aromatic sulfated antigen recognition by alphabeta CD8+ Th2 T lymphocytes might underlie the cellular mediation of human allergy to plant allergens.

Allergens↗
PubMed1992

Roles for secondary metabolites in plants.

More than about 20,000 secondary metabolites have now been identified and their isolation and characterization continues at an undiminishing rate. Although the production of most secondary metabolites is under genetic control, in relatively few cases have convincing arguments been put forward to rationalize their occurrence in terms of primary metabolic functions. Whatever the initial reason for their evolution, secondary metabolites are now an essential part of the armamentaria used by plants in the battle to survive and propagate, to the extent where the expenditure of energy, photosynthate and nutrients for their production can be demonstrated to be 'cost effective' for that. Their role may centre on defence of the producer against predators (herbivores), pathogens or competitors, on aid to pollination or seed dispersal, or on protection against or adaptation to extrinsic abiotic factors, or on combinations of these functions. Various examples are given in support of this argument.

Alleles↗
PubMed2004

Floral zygomorphy, the recurring evolution of a successful trait.

The flowers of the primitive angiosperm plants were radially symmetrical (actinomorphic). Flowers with bilateral symmetry (zygomorphic) evolved in several clades independently as an adaptation to specialized methods of pollination and played an important role in the diversification of flowering plants. In the model species Antirrhinum majus (snapdragon), the related genes CYCLOIDEA (CYC) and DICHOTOMA (DICH) are key in the development of this trait. This raises the question of whether they played a role in the evolution of floral bilateral symmetry. To address this, the evolution of CYC in relation to the evolution of zygomorphy is being investigated. Phylogenetic and functional analyses of CYC-like genes are being carried out in groups either closely related to Antirhinum or in families where zygomorphy evolved as an independent event. In addition, the origin of zygomorphy is being studied by comparing the function of CYC-like genes in species with zygomorphic flowers with their function in species with radially symmetrical flowers.

Biological Evolution↗