Diagnosis and Management of Grain-Induced Asthma

Grain-induced asthma is a frequent occupational allergic disease mainly caused by inhalation of cereal flour or powder. The main professions affected are bakers, confectioners, pastry factory workers, millers, farmers, and cereal handlers. This disorder is usually due to an IgE-mediated allergic response to inhalation of cereal flour proteins. The major causative allergens of grain-related asthma are proteins derived from wheat, rye and barley flour, although baking additives, such as fungal α-amylase are also important. This review deals with the current diagnosis and treatment of grain-induced asthma, emphasizing the role of cereal allergens as molecular tools to enhance diagnosis and management of this disorder. Asthma-like symptoms caused by endotoxin exposure among grain workers are beyond the scope of this review. Progress is being made in the characterization of grain and bakery allergens, particularly cereal-derived allergens, as well as in the standardization of allergy tests. Salt-soluble proteins (albumins plus globulins), particularly members of the α-amylase/trypsin inhibitor family, thioredoxins, peroxidase, lipid transfer protein and other soluble enzymes show the strongest IgE reactivities in wheat flour. In addition, prolamins (not extractable by salt solutions) have also been claimed as potential allergens. However, the large variability of IgE-binding patterns of cereal proteins among patients with grain-induced asthma, together with the great differences in the concentrations of potential allergens observed in commercial cereal extracts used for diagnosis, highlight the necessity to standardize and improve the diagnostic tools. Removal from exposure to the offending agents is the cornerstone of the management of grain-induced asthma. The availability of purified allergens should be very helpful for a more refined diagnosis, and new immunomodulatory treatments, including allergen immunotherapy and biological drugs, should aid in the management of patients with this disorder.

One Hundred Years of Grain Omics: Identifying the Glutens That Feed the World.

Glutens, the storage proteins in wheat grains, are a major source of protein in human nutrition. The protein composition of wheat has therefore been an important focus of cereal research. Proteomic tools have been used to describe the genetic diversity of wheat germplasms from different origins at the level of polymorphisms in alleles encoding glutenin and gliadin, the two main proteins of gluten. More recently, proteomics has been used to understand the impact of specific gluten proteins on wheat quality. Here we review the impact of proteomics on the study of gluten proteins as it has evolved from fractionation and electrophoretic techniques to advanced mass spectrometry. In the postgenome era, proteomics is proving to be essential in the effort to identify and understand the interactions between different gluten proteins. This is helping to fill in gaps in our knowledge of how the technological quality of wheat is determined by the interaction between genotype and environment. We also collate information on the various storage protein alleles identified and their prevalence, which makes it possible to infer the effects of wheat selection on grain protein content. We conclude by reviewing the more recent use of transgenesis aimed at improving the quality of gluten.

On the Controversy About the Presence of Grain Boundary Sliding in Mg AZ31

Highly-textured, rolled AZ31 sheet material shows a significant drop in the plastic anisotropy (r-value; r=εw/εt) in tension between 25°C and 200°C. This behavior was initially explained as a result of the increased activity of non-basal slip with increased temperature. Other authors suggested, however, that the mechanism resp onsible for this phenomenon was the activation of grain boundary sliding (GBS). Here, in-situ ten sile tests have been carried out in an SEM at various temperatures in order to obtain further evi dence of the role of GBS during moderate to high temperature deformation of Mg alloys, which remains highly controversial.

Influence of grain size and compaction of different solid fuels on the layer ignition temperature

The results obtained from these analyses provide some clarifications about the thermal behaviour of the products and also enough information to design some prevention measurements in these facilities to avoid or at least minimize the risk of ignition of a dust layer.

Desynchronization of cells on the developmental path triggers the formation of spiral waves of cAMP during Dictyostelium aggregation

Whereas it is relatively easy to account for the formation of concentric (target) waves of cAMP in the course of Dictyostelium discoideum aggregation after starvation, the origin of spiral waves remains obscure. We investigate a physiologically plausible mechanism for the spontaneous formation of spiral waves of cAMP in D. discoideum. The scenario relies on the developmental path associated with the continuous changes in the activity of enzymes such as adenylate cyclase and phosphodiesterase observed during the hours that follow starvation. These changes bring the cells successively from a nonexcitable state to an excitable state in which they relay suprathreshold cAMP pulses, and then to autonomous oscillations of cAMP, before the system returns to an excitable state. By analyzing a model for cAMP signaling based on receptor desensitization, we show that the desynchronization of cells on this developmental path triggers the formation of fully developed spirals of cAMP. Developmental paths that do not correspond to the sequence of dynamic transitions no relay-relay-oscillations-relay are less able or fail to give rise to the formation of spirals.

Visual stimuli induce waves of electrical activity in turtle cortex

The computations involved in the processing of a visual scene invariably involve the interactions among neurons throughout all of visual cortex. One hypothesis is that the timing of neuronal activity, as well as the amplitude of activity, provides a means to encode features of objects. The experimental data from studies on cat [Gray, C. M., Konig, P., Engel, A. K. & Singer, W. (1989) Nature (London) 338, 334–337] support a view in which only synchronous (no phase lags) activity carries information about the visual scene. In contrast, theoretical studies suggest, on the one hand, the utility of multiple phases within a population of neurons as a means to encode independent visual features and, on the other hand, the likely existence of timing differences solely on the basis of network dynamics. Here we use widefield imaging in conjunction with voltage-sensitive dyes to record electrical activity from the virtually intact, unanesthetized turtle brain. Our data consist of single-trial measurements. We analyze our data in the frequency domain to isolate coherent events that lie in different frequency bands. Low frequency oscillations (<5 Hz) are seen in both ongoing activity and activity induced by visual stimuli. These oscillations propagate parallel to the afferent input. Higher frequency activity, with spectral peaks near 10 and 20 Hz, is seen solely in response to stimulation. This activity consists of plane waves and spiral-like waves, as well as more complex patterns. The plane waves have an average phase gradient of ≈π/2 radians/mm and propagate orthogonally to the low frequency waves. Our results show that large-scale differences in neuronal timing are present and persistent during visual processing.

Three-dimensional scroll waves of cAMP could direct cell movement and gene expression in Dictyostelium slugs.

Complex three-dimensional waves of excitation can explain the observed cell movement pattern in Dictyostelium slugs. Here we show that these three-dimensional waves can be produced by a realistic model for the cAMP relay system [Martiel, J. L. & Goldbeter, A. (1987) Biophys J. 52, 807-828]. The conversion of scroll waves in the prestalk zone of the slug into planar wave fronts in the prespore zone can result from a smaller fraction of relaying cells in the prespore zone. Further, we show that the cAMP concentrations to which cells in a slug are exposed over time display a simple pattern, despite the complex spatial geometry of the waves. This cAMP distribution agrees well with observed patterns of cAMP-regulated cell type-specific gene expression. The core of the spiral, which is a region of low cAMP concentration, might direct expression of stalk-specific genes during culmination.

Distribution of grain size and clay minerals in surface sediments of the Kara Sea (Fig 4, 5)

In this paper, we summarize data on terrigenous sediment supply in the Kara Sea and its accumulation and spatial and temporal variability during Holocene times. Sedimentological, organic-geochemical, and micropaleontological proxies determined in surface sediments allow to characterize the modern (riverine) terrigenous sediment input. AMS-14C dated sediment cores from the Ob and Yenisei estuaries and the adjacent inner Kara Sea were investigated to determine the terrigenous sediment fluxes and their relationship to paleoenvironmental changes. The variability of sediment fluxes during Holocene times is related to the post-glacial sea-level rise and changes in river discharge and coastal erosion input. Whereas during the late/middle Holocene most of the terrigenous sediments were deposited in the estuaries and the areas directly off the estuaries, huge amounts of sediments accumulated on the Kara Sea shelf farther north during the early Holocene before about 9 cal kyr BP. The maximum accumulation at that time is related to the lowered sea level, increased coastal erosion, and increased river discharge. Based on sediment thickness charts, echograph profiles and sediment core data, we estimate an average Holocene (0-11 cal kyr BP) annual accumulation of 194,106 t/yr of total sediment for the whole Kara Sea. Based on late Holocene (modern) sediment accumulation in the estuaries, probably 12,106 t/yr of riverine suspended matter (i.e. about 30% of the input) may escape the marginal filter on a geological time scale and is transported onto the open Kara Sea shelf. The high-resolution magnetic susceptibility record of a Yenisei core suggests a short-term variability in Siberian climate and river discharge on a frequency of 300-700 yr. This variability may reflect natural cyclic climate variations to be seen in context with the interannual and interdecadal environmental changes recorded in the High Northern Latitudes over the last decades, such as the NAO/AO pattern. A major decrease in MS values starting near 2.5 cal kyr BP, being more pronounced during the last about 2 cal kyr BP, correlates with a cooling trend over Greenland as indicated in the GISP-2 Ice Core, extended sea-ice cover in the North Atlantic, and advances of glaciers in western Norway. Our still preliminary interpretation of the MS variability has to be proven by further MS records from additional cores as well as other high-resolution multi-proxy Arctic climate records.