bluuebunny/crossref_metadata_2025_split huggingface dataset:
Asthma among secondary schoolchildren in relation to the school environment
Authors: SMEDJE G. , NORBÄCK D. , EDLING C. 
Published: April 2006

SummaryBackground
Poor indoor air quality has been suggested to be related to the increase in the prevalence of asthma that has occurred in the western world, especially among children and young persons. Apart from the home, school is the most important indoor environment for children.Objectives
The aims were to study the prevalence of current asthma among secondary pupils and its relationship to the school environment, but also to personal factors and domestic exposures.Methods
Data on asthmatic symptoms, other health aspects, and domestic exposures were gathered using a questionnaire which was sent to 762 pupils in the seventh form (13–14 years old) in 11 randomly chosen schools in the county of Uppsala in Sweden. Pupils answering‘yes’ to having had asthma diagnosed by a physician, and having had recent asthma attacks, or who used asthma medication were defined as having current asthma. Data on exposures at school were gathered by measurements in 28 classrooms. The relationship between asthma and exposures was analysed by multiple logistic regression.Results
The questionnaire was completed by 627 (82%). Current asthma was found among 40 pupils (6.4%). Current asthma was more common in those who had an atopic disposition, or food allergy, or who had attended a day care centre for several years. Controlling for these factors, current asthma was related to several factors in the school environment. There were more pupils with current asthma in schools that were larger, had more open shelves, lower room temperature, higher relative air humidity, higher concentrations of formaldehyde or other volatile organic compounds, viable moulds or bacteria or more cat allergen in the settled dust.Conclusions
Although the pupils attended school for a minor part of their time, our study indicates that the quality of the school environment is of importance and may affect asthmatic symptoms.
Immunotherapy vs inhaled budesonide in bronchial asthma: an open, parallel, comparative trial
Authors: SHAIKH W. A. 
Published: April 2006

SummaryBackground
Budesonide, an inhaled corticosteroid and specific immunotherapy, are both routinely used in the treatment of bronchial asthma. However, there are as yet, no studies comparing the effects of budesonide vs immunotherapy.Objective
The aim of this study is to compare the effects of budesonide with immunotherapy in patients having perennial asthma.Methods
This study is an open, parallel, comparative trial, in which 51 young patients were administered either immunotherapy or budesonide for 1 year and their global symptom scores and FEV1, values assessed. Both treatments were abruptly discontinued after 12 months and the effects of cessation analysed.Results
The use of budesonide resulted in a faster and more striking improvement during the first few months as compared to immunotherapy, with an even more rapid decline in benefits on cessation of budesonide. Immunotherapy on the other hand, resulted in slow but steady improvement which did not decline as rapidly as budesonide on cessation.Conclusion
Although this was an open trial, it could be concluded that relief with inhaled corticosteroids in bronchial asthma is more rapid than immunotherapy; however the decline in benefit on cessation of inhaled cortieosteroid is even more rapid, a phenomenon not seen with immunotherapy.
Characterization of allergens in Apiaceae spices: anise, fennel, coriander and cumin
Authors: JENSEN‐JAROLIM E. , LEITNER A. , HIRSCHWEHR R. , KRAET D. , WÜTHRICH B. , SCHEINER O. , GRAF J. , EBNER C. 
Published: April 2006

SummaryBackground
Symptoms elicited by IgEmediated food allergy range from mild local to severe systemic reactions. Allergens in spices are particularly dangerous due to their hidden presence in many dishes.Objectives and Methods
According to clinical observations, mugwort and birch pollen allergy, and hypersensitivity to spices are frequently associated, but the crossreacting compounds were not defined so far. We tested sera of 15 patients who experienced adverse reactions to spiced food and characterized their IgE‐binding patterns on anise, fennel, coriander and cumin extracts through immunoblot and inhibition experiments.Results
The use of anti‐Bet v 1 (MoAb) and anti‐profilin (rabbit) antibodies revealed the presence of crossreacting allergens in the tested spice extracts. Inhibition experiments showed that IgE‐binding to allergens in Apiaceae spices could be blocked by preincubation of sera with rBet v I or rBet v 2 (birch profilin). Moreover, we detected crossreacting allergenic molecules in the molecular weight range of 60kDa. IgE‐binding to spice allergens occurred only with sera of 10/15 (66%) patients with allergy to pollen (birch, niugwort) and/or celeriac. In five out of 15 (33%) patients with a history of adverse reaction to spices, but without pollen and celeriac allergy, no IgE‐binding to any spice protein could be demonstrated. It is possible that these clinical reactions could bo elicited by other types of hypersensitivity (Type II. IIII, IV), however, as spices contain highly reactive substances, the symptoms may most likely be classified as food‐intolerant.Conclusions
Bet v 1‐ and profilin‐related allergens may, besides higher molecular weight allergenic molecules, be responsible for Type I allergy to anise, fennel, coriander or cumin, members of the Apiaceae.
Comparison of a radioallergosorbent (RAST) inhibition method and a monoclonal enzyme linked immunosorbent assay (ELISA) for aeroallergen measurement
Authors: RENSTRÖM A. , GORDON S. , LARSSON P. H. , TEE R. D. , TAYLOR A. J. NEWMAN , MALMBERG P. 
Published: April 2006

SummaryBackground
Mouse and rat urinary proteins are potent occupational allergens for exposed personnel. Methods of measuring airborne allergens differ greatly, and reported levels of allergens vary considerably between laboratories.Objectives
To compare the values obtained using two different methods of allergen detection.Methods
Air samples were collected in rat rooms in Sweden and the United Kingdom at 2 L/min on to polytetrafluoroethylene (PTFE) filters and extracted in buffer containing 0.5% v/v Tween 20. Airborne rat urinary allergen (RUA) was measured in all samples by both RAST inhibition using a polyclonal human serum pool (UK) and a two monoclonal antibody sandwich ELISA employing antibodies specific for Rat n 1.02 (α2u‐globulin) (Sweden).Results
The two methods gave values which were correlated (r2 log values = 0.72, P < 0.0001), but differed by several orders of magnitude (median [range] ratio of RAST inhibition/ELISA = 316 [7‐2680]. There was a systematic bias; as the absolute values increased, the difference in the measurements increased. The rat urine standards used were antigenically similar.Conclusions
A large contrast in RUA values obtained from the two assays was observed in this study. This may be primarily due to methodological differences, but variations in antibody specificities or composition of allergenic epitopes in the air samples may contribute. The results demonstrate that standardization of methods and antibodies is necessary before interlaboratory comparisons can be made.
Association between inflammation and epithelial damage‐restitution processes in allergic airways in vivo
Authors: ERJEFÄLT J. S. , KORSGREN M. , NILSSON M. C. , SUNDLER F. , PERSSON C. G. A. 
Published: April 2006

SummaryBackground
Associations between allergen challenge‐induced sites of epithelial damage and the distribution of leucocytes and extravasated plasma remain unexplored.Objective
To study neutrophils, eosinophils, and fibrinogen at allergen challenge‐induced patchy epithelial damage‐restitution sites in guinea‐pig trachea.Methods
After local challenge tracheal tissue (cryo sections and whole‐mounts) and lumen (selective tracheal lavage) were examined at 1, 5, and 24 h. Eosinophils, neutrophils and fibrinogen were identified by histochemistry.Results
Neutrophils increased markedly in tracheal lavage fluids and in tissue and were strongly associated with the challenge‐induced epithelial craters of damage‐restitution. At 1 and 24 h eosinophils were increased in the tracheal lumen whereas the surrounding tissue displayed a reversed pattern. Gels rich in fibrinogen, neutrophils, and eosinophils were present in epithelial crater areas, protruding into the lumen. Clusters of free eosinophil granules, Cfegs, released through lysis of eosinophils, and neutrophils with long cytoplasmatic protrusions abounded in these crater areas.Conclusions
The present findings provide important new insights into allergic airways where sites of epithelial damage‐restitution processes emerge as the major loci for eosinophil, neutrophil, and plasma protein activities, the latter likely causing leukocyte adhesion and activation in vivo. The disttibution of eosinophils in this study suggests roles of these cells both in airway mucosa and in regional lymph nodes. Based on the present study we also propose that lysis of eosinophils and Cfegs generation are a major paradigm for activation of these cells in vivo.
Sapwood water storage: its contribution to transpiration and effect upon water conductance through the stems of old‐growth Douglas‐fir
Authors: WARING R. H. , RUNNING S. W. 
Published: April 2006

Abstract Enough water is stored in the sapwood of large Douglas‐fir to significantly contribute to transpiration. Sapwood water content falls through the season, causing the wood's conductivity to fall. This leads to low leafwater potentials, stomatal closure, and reduced photosynthesis by the trees.The amount of water stored in the sapwood of Douglasfir 50‐60 m tall, growing in the Cascade Mountains of Oregon, was estimated periodically over two seasons from measurements of sapwood relative water content (Rs). The relationship between Rs and volume of water contained in the sapwood was determined in the laboratory, and an equation describing the variation of relative conductivity (K) with Rs was derived from the literature. Stomatal conductance (ks) and leaf water potentials were measured in the field.The relative conductivity of the sapwood was calculated from estimates of the flow rate through the tree and differences in water potential between dawn and the time of comparison. Flow rate was assumed to equal transpiration rate, calculated from the Penman‐Monteith equation using measured ks values. A sixfold decrease in K during the summer was attributed to changes in Rs. The maximum observed diurnal variation in K would require a change in RS estimated at 25%.About 270 m3 ha−1 (27 mm) of water were stored in sapwood, and 75% of that was in the stemwood. Withdrawal from this store reached 1.7 mm day−1 on clear days after cloudy or rainy weather. Recharge could be almost as fast (up to 1.6 mm day−1) after rain, but was very slow if the foliage remained wet.
Dawn signal as a rhythmical timer for the seasonal adaptive variation of CAM: a model
Authors: MOREL C. , QUEIROZ O. 
Published: April 2006

Abstract Photoperiodism, known to control the level of CAM in different types of CAM plants (e.g. Kalanchoe blossfeldiana, Bryophyllum daigremontianum), would act as a reliable timer for seasonal coherent adaptation. Two different endogenous rhythms (malic enzyme activity, PEP carboxylase capacity) appear to be separately coupled to dawn and dusk, respectively, thus achieving time‐compartmentation of CAM; this feature suggests involvement of an ‘internal coincidence’ type of clock mechanism.Persistence in continuous darkness of the rhythm of malic enzyme activity (measured by label incorporation into pyruvate or by CO2 output) establishes its endogenous character and shows that light is not necessary for malate decarboxylation. The role of the dawn signal would be to entrain the CAM system, i.e. to phase the endogenous rhythm of malic enzyme activity correctly to local time. The possibility of an effect of the phase of the PEP carboxylase rhythm on the phase of the decarboxylation rhythm is ruled out by the presence of the intermediary malate storage step. Phase responses to red and to far‐red show that phytochrome is involved in rephasing the rhythm of malic enzyme activity.The relative position of dusk affords a ‘measurement’ of the season by the CAM system entrained by dawn. According to the dusk‐dawn interval, the level of PEP carboxylase capacity (amount of active enzyme) is modified, resulting in changes of CAM level (high activity under short days).
Light dark modulation of glycogen phosphorylase activity in the blue‐green alga, Anacystis nidulans
Authors: LEHMANN M. , WÖBER G. 
Published: April 2006

Abstract The photoautotrophic procaryote, Anacystis nidulans, accumulates glycogen as a carbon reserve during illumination and nitrogen limitation. Glycogen phosphorylase participates in the mobilization of the polysaccharide in a dark period and was found to be a point of regulatory control of glycogen degradation. Specific enzyme activity of non‐dividing cells increased twofold upon transfer from light to dark and decreased again upon re‐illumination. This dark stimulation of enzyme activity was not inhibited by either rifampicin or chloramphenicol, whereas a light‐induced decrease was abolished by DCMU, an inhibitor of photosynthetic electron transport. Deactivation of glycogen phosphorylase could be simulated by dithiothreitol in vitro. A spheroplast lysate either with or without chromatophores and a partially purified glycogen‐enzyme complex responded to dithiothreitol.These results are compatible with an interpretation in terms of redox changes taking place with the enzyme in an activation/deactivation cycle. The inactive form maintained in a reduced state by photosynthetic electron transport is thought to be converted into an active form in the dark.
Dissociation of H + extrusion from K+ uptake by means of lipophilic cations
Authors: BELLANDO M. , TROTTA A. , BONETTI A. , COLOMBO R. , LADO P. , MARRE E. 
Published: April 2006

Abstract Dissociation of active H+ extrusion (−ΔH+) from K+ uptake in pea and maize root segments was attempted by substituting K+ in the incubation medium with lipophilic cations assumed to enter the cell by passive, non‐specific, permeation through the lipid component of the plasmalemma. Among the compounds tested, tributylbenzylammonium significantly stimulated −ΔH+ in the absence of other monovalent cations in the medium. This effect was much more evident when the experiment was carried out in the presence of fusicoccin, which strongly stimulates proton extrusion and monovalent cation uptake, and hyperpolarizes the trans‐membrane electric potential in these materials. Also the lipophilic cations tetraphenylphosphonium, dimethyldibenzylammonium and hexylguanidine markedly stimulated FC‐promoted −ΔH+. Octylguanidine at a low concentration induced an early stimulation followed by a strong inhibition of −ΔH+. A complete lack of additivity was observed between the effects of lipophilic cations and that of K+ on H+ extrusion. Lipophilic cations severely inhibited K+ uptake.These data are interpreted as supporting the view of an electric, rather than a chemical, (namely, involving the same carrier system) nature of the coupling of active H+ extrusion with K+ influx.
Effect of ethylene on auxin transport and metabolism in midrib sections in relation to leaf abscission of woody plants
Authors: RIOV J. , GOREN R. 
Published: April 2006

Abstract The relationship between ethylene‐induced leaf abscission and ethylene‐induced inhibition of auxin transport in midrib sections of the leaf blade of Citrus sinensis L. Osbeck, Populus deltoides Bart, and Eucalyptus camaldulensis Dehn. was studied. These species differed greatly in their abscission response to ethylene. The kinetic trend of abscission resembled that of the inhibition of auxin transport in all three species. It is suggested that one of the main actions of ethylene in the leaf blade is to inhibit auxin transport in the veinal tissues, thus reducing the amount of auxin transported from the leaf blade to the abscission zone.Ethylene inhibited transport of both IAA (indole‐3‐acetic acid) and NAA (α‐naphthaleneacetic acid) in the midrib sections. However, while ethylene enhanced the conjugation of IAA with aspartic acid and glucose in the apical (absorbing) segment of the midrib sections, it had little effect on the conjugation of NAA. The data indicate that auxin destruction through conjugation does not play a major role in the inhibition of auxin transport by ethylene.
The role of calcium in buffering soils
Authors: BACHE B. W. 
Published: April 2006

Abstract. Calcium is the soluble cation that occurs in largest amount in most soils. It does not take part directly in the proton transfer reactions involved in pH‐buffering, but it provides the cation charge balance for these reactions. It is also the complementary cation in formulations of chemical potential for many other ions in soils. The presence of free calcium carbonate in calcareous soils. The presence of free calcium carbonate in calcareous soils ensures a very high soil buffer capacity; dAB/dpH ≃ 1000 Eq. m−3.In acid mineral soils, dissolution and precipitation of aluminium ions contribute to the buffering processes, but most of the buffering in non‐calcareous soils is caused by specific ion adsorption at variable‐charge sites, in particular those associated with the dissociation of humus acids. Typical buffer capacity values of non‐calcareous soils vary from 10 Eq. m−3 for sandy soils to 100 Eq. m−3 for peats. The pH changes associated with buffering are produced by leaching of calcium from soil, or by adding calcium to soil in liming materials.
Calcium and plant action potentials
Authors: BEILBY M. J. 
Published: April 2006

Abstract. Under normal conditions the action potential in Characeae is dependent on the presence of both Cl− and Ca2+. Cl− seems to play a straightforward part as a transient depolarizing flow. The role of Ca2+, however, is emerging as an increasingly complex one: there are Ca2+ concentration changes in the cytoplasm, as well as transient Ca2+ currents across the plasmalemma and possibly the tonoplast. In most Characeae Ca2+ is necessary for the Cl− channel to function, and it is also involved in the cessation of the cytoplasmic streaming observed at the time of excitation.The function of Ca2+ at the time of the action potential is being revealed by experimental techniques of increasing sophistication. The development of these methods and possible associated artefacts are considered.
The dual role of oxygen in avocado fruit respiration: Kinetic analysis and computer modelling of diffusion‐affected respiratory oxygen isotherms
Authors: TUCKER M. L. , LATIES G. G. 
Published: April 2006

Abstract. Oxygen plays a dual role in affecting the rate of respiration of avocado fruit (Persea americana Mill, cv. Hass). The respiration rate v. oxygen concentration curve for steady state avocado fruit respiration is biphasic. The curve becomes monophasic, however, when measured under conditions of rapidly changing oxygen concentration in a closed circulating system. The results are interpreted as indicating that oxygen at relatively high concentrations modulates respiration independent of its interaction with the terminal oxidase—presumably cytochrome oxidase.A computer model is presented which takes into account the effect of diffusion barriers on the kinetics of oxygen utilization as a function of concentration in avocado fruit. The model is used to make predictions concerning the apparent Km of the terminal oxidase or oxidases in avocado fruit. It is concluded that the apparent Km of the terminal oxidase of uninhibited avocado fruit is that of cytochrome oxidase, and that the alternative, cyanide‐resistant oxidase of avocado fruit does not contribute appreciably to the uninhibited respiration of preclimacteric or climacteric avocado fruit.
Partitioning stomatal and non‐stomatal limitations to photosynthesis
Authors: JONES H. G. 
Published: April 2006

Abstract. Plant scientists concerned both with crop improvement and with understanding the control mechanisms of complex processes such as photosynthesis need to identify those processes that are most important in restricting the overall rate and to quantify the relative importance of different components. The techniques that have been used for quantifying the relative importance of component processes in limiting net assimilation rate are reviewed and related to a fundamental definition based on sensitivity analysis. It is concluded that many methods currently in use, including standard resistance analysis, frequently give very misleading answers.In addition, possible methods for apportioning the contributions of different component processes to observed changes in net photosynthetic rate (for example after stress) are also reviewed and compared against a fundamental approach based on sensitivity analysis. Unfortunately, the detailed time course of changes in mesophyll and stomatal properties that is required for application of the basic sensitivity analysis is seldom likely to be available, so that it is usually necessary to adopt an approximate method. The standard approximation that is recommended for calculating the contributions of different component processes to a change in assimilation rate, involves measurements at the initial and final states only. The various methods discussed in this paper are compared using published photosynthetic data for a range of species.
Physical, chemical and biological characteristics* of CO2 gas flux across the air‐water interface
Authors: SMITH S. V. 
Published: April 2006

Abstract Carbon dioxide gas flux across the air‐water interface is most often treated as a ‘simple’ physical process, primarily responding to wind speed and water temperature. Available experimental data yield an exponential regression equation relating wind speed to the thickness of a stagnant boundary film through which gas diffuses to or from the water. Flux of CO2 is influenced by CO2 hydration reactions in the stagnant boundary layer. High pH and a thick stagnant boundary layer favour chemical enhancement of the CO2 gas flux.The rate of CO2 flux reflects the sum of net organic metabolism plus CaCO3 reactions. Some interesting gas‐flux constraints on the rate of net organic carbon production and on global geochemical cycling of CaCO3 emerge. At high pH (circa 10), the maximum net organic carbon production which can be supported by CO2 flux across the air‐water interface is about 0.06 mol C m&2 d&1. On a global scale, organic C, not atmospheric C, appears to account for the ‘CO2’ term in the classical CaCO3 dissolution‐precipitation reaction.
Cations stimulate proton pumping in Catharanthus roseus cells: implication of a redox system?
Authors: BELKOURA M. , RANJEVA R. , MARIGO G. 
Published: April 2006

Abstract During growth, cultured Catharanthus oseus cells produce a transient acidification of the culture medium that may be controlled by cations. The removal of divalent ions from the medium by the chelator EGTA resulted in an inhibition of this acidification. Conversely, acidification can be stimulated by the addition of Ca2+, Mg2+ and La3+ in the basal medium.This acidification process and the proton‐linked redox pump previously described (Marigo & Belkoura, 1985) respond in a similar manner to cations. These two systems, which are both inhibited by the Ca2+ ‐calmodulin antagonist calmidazolium, could be regulated by the Ca2+‐calmodulin complex. By using ionic surfactant (CP+, SDS−) it was demonstrated that the net surface charge of the plasmalemma plays a role in the activation of the two pumping processes. These results are interpreted to indicate that a transmembrane redox system could provide the energy for electrogenic proton extrusion.