Leertechnologie in de lage landen

Op het terrein van onderwijs en ICT investeren onderwijsinstellingen, bedrijven, brancheorganisaties en overheden in het bewerkstelligen van leertechnologie-afspraken. Het doel van die gezamenlijke inspanning is om het onderwijs te kunnen verbeteren en efficiënter te maken. Gedeelde opvattingen, vastgelegd in specificaties en standaarden, maken uitwisseling van gegevens mogelijk tussen uiteenlopende systemen. Dat biedt grote kansen voor onderwijsvernieuwing. Basisgegevens hoeven slechts op één plek onderhouden te worden, maar zijn toch voor iedere instelling bruikbaar: eenmaal gemaakte lesmaterialen kunnen in verschillende leeromgevingen worden ingezet, studenten kunnen zich flexibel inschrijven voor cursussen aan verschillende instellingen terwijl hun studievoortgang zonder probleem wordt geregistreerd. Deze processen zijn essentiële voorwaarden voor een duurzame ontwikkeling van e-learning in de Lage Landen. Als samenwerkingsorganisatie voor het hoger onderwijs in Nederland neemt SURF deel aan de mars naar standaardisatie binnen de leertechnologie. De SURF SiX expertisegroep, een Special Interest Group van SURF, onderneemt activiteiten om realisatie en gebruik van leertechnologie-afspraken te bevorderen die voor het Nederlandse hoger onderwijs bruikbaar en nuttig zijn en die blijvende aansluiting van Nederland bij internationale e-learningontwikkelingen garanderen. Met dit boek geeft SURF SiX een brede groep onderwijsontwikkelaars en geïnformeerde eindgebruikers inzicht in de huidige Nederlandse situatie op het gebied van leertechnologie-afspraken. Daarnaast wil dit boek laten zien dat leertechnologiespecificaties en standaarden meerwaarde hebben.Stichting Sur

Characterization of PR-10 genes from eight Betula species and detection of Bet v 1 isoforms in birch pollen

<p>Abstract</p> <p>Background</p> <p>Bet v 1 is an important cause of hay fever in northern Europe. Bet v 1 isoforms from the European white birch <it>(Betula pendula) </it>have been investigated extensively, but the allergenic potency of other birch species is unknown. The presence of Bet v 1 and closely related PR-10 genes in the genome was established by amplification and sequencing of alleles from eight birch species that represent the four subgenera within the genus <it>Betula</it>. Q-TOF LC-MS^Ewas applied to identify which PR-10/Bet v 1 genes are actually expressed in pollen and to determine the relative abundances of individual isoforms in the pollen proteome.</p> <p>Results</p> <p>All examined birch species contained several PR-10 genes. In total, 134 unique sequences were recovered. Sequences were attributed to different genes or pseudogenes that were, in turn, ordered into seven subfamilies. Five subfamilies were common to all birch species. Genes of two subfamilies were expressed in pollen, while each birch species expressed a mixture of isoforms with at least four different isoforms. Isoforms that were similar to isoforms with a high IgE-reactivity (Bet v 1a = PR-10.01A01) were abundant in all species except <it>B. lenta</it>, while the hypoallergenic isoform Bet v 1d (= PR-10.01B01) was only found in <it>B. pendula </it>and its closest relatives.</p> <p>Conclusion</p> <p>Q-TOF LC-MS^Eallows efficient screening of Bet v 1 isoforms by determining the presence and relative abundance of these isoforms in pollen. <it>B. pendula </it>contains a Bet v 1-mixture in which isoforms with a high and low IgE-reactivity are both abundant. With the possible exception of <it>B. lenta</it>, isoforms identical or very similar to those with a high IgE-reactivity were found in the pollen proteome of all examined birch species. Consequently, these species are also predicted to be allergenic with regard to Bet v 1 related allergies.</p

IgE Cross-Reactivity of Cashew Nut Allergens

Background: Allergic sensitisation towards cashew nut often happens without a clear history of eating cashew nut. IgE cross-reactivity between cashew and pistachio nut is well described; however, the ability of cashew nut-specific IgE to cross-react to common tree nut species and other Anacardiaceae, like mango, pink peppercorn, or sumac is largely unknown. Objectives: Cashew nut allergic individuals may cross-react to foods that are phylogenetically related to cashew. We aimed to determine IgE cross-sensitisation and cross-reactivity profiles in cashew nut-sensitised subjects, towards botanically related proteins of other Anacardiaceae family members and related tree nut species. Method: Sera from children with a suspected cashew nut allergy (n = 56) were assessed for IgE sensitisation to common tree nuts, mango, pink peppercorn, and sumac using dot blot technique. Allergen cross-reactivity patterns between Anacardiaceae species were subsequently examined by SDS-PAGE and immunoblot inhibition, and IgE-reactive allergens were identified by LC-MS/MS. Results: From the 56 subjects analysed, 36 were positive on dot blot for cashew nut (63%). Of these, 50% were mono-sensitised to cashew nuts, 19% were co-sensitised to Anacardiaceae species, and 31% were co-sensitised to tree nuts. Subjects co-sensitised to Anacardiaceae species displayed a different allergen recognition pattern than subjects sensitised to common tree nuts. In pink peppercorn, putative albumin- and legumin-type seed storage proteins were found to cross-react with serum of cashew nut-sensitised subjects in vitro. In addition, a putative luminal binding protein was identified, which, among others, may be involved in cross-reactivity between several Anacardiaceae species. Conclusions: Results demonstrate the in vitro presence of IgE cross-sensitisation in children towards multiple Anacardiaceae species. In this study, putative novel allergens were identified in cashew, pistachio, and pink peppercorn, which may pose factors that underlie the observed cross-sensitivity to these species. The clinical relevance of this widespread cross-sensitisation is unknown.</p

Effect of starch-based biomaterials on the in vitro proliferation and viability of osteoblast-like cells

The cytotoxicity of starch-based polymers was investigated using different methodologies. Poly-L-lactic acid (PLLA) was used as a control for comparison purposes. Extracts of four different starch-based blends (corn starch and ethylene vinyl alcohol (SEVA-C), corn starch and cellulose acetate (SCA), corn starch and polycaprolactone (SPCL) and starch and poly-lactic acid (SPLA70) were prepared in culture medium and their toxicity was analysed. Osteoblast-like cells (SaOs-2) were incubated with the extracts and cell viability was assessed using the MTT test and a lactate dehydrogenase (LDH) assay. In addition DNA and total protein were quantified in order to evaluate cell proliferation. Cells were also cultured in direct contact with the polymers for 3 and 7 days and observed in light and scanning electron microscopy (SEM). LDH and DNA quantification revealed to be the most sensitive tests to assess respectively cell viability and cell proliferation after incubation with starch-based materials and PLLA. SCA was the starch blend with higher cytotoxicity index although similar to PLLA polymer. Cell adhesion tests confirmed the worst performance of the blend of starch with cellulose acetate but also showed that SPCL does not perform as well as it could be expected. All the other materials were shown to present a comparable behaviour in terms of cell adhesion showing slight differences in morphology that seem to disappear for longer culture times. The results of this study suggest that not only the extract of the materials but also their three-dimensional form has to be biologically tested in order to analyse material-associated parameters that are not possible to consider within the degradation extract. In this study, the majority of the starch-based biomaterials presented very promising results in terms of cytotoxicity, comparable to the currently used biodegradable PLLA which might lead the biocompatibility evaluation of those novel biomaterials to other studies.Fundação para a Ciência e a Tecnologia (FCT

Presence of celiac disease epitopes in modern and old hexaploid wheat varieties: wheat breeding may have contributed to increased prevalence of celiac disease

Gluten proteins from wheat can induce celiac disease (CD) in genetically susceptible individuals. Specific gluten peptides can be presented by antigen presenting cells to gluten-sensitive T-cell lymphocytes leading to CD. During the last decades, a significant increase has been observed in the prevalence of CD. This may partly be attributed to an increase in awareness and to improved diagnostic techniques, but increased wheat and gluten consumption is also considered a major cause. To analyze whether wheat breeding contributed to the increase of the prevalence of CD, we have compared the genetic diversity of gluten proteins for the presence of two CD epitopes (Glia-α9 and Glia-α20) in 36 modern European wheat varieties and in 50 landraces representing the wheat varieties grown up to around a century ago. Glia-α9 is a major (immunodominant) epitope that is recognized by the majority of CD patients. The minor Glia-α20 was included as a technical reference. Overall, the presence of the Glia-α9 epitope was higher in the modern varieties, whereas the presence of the Glia-α20 epitope was lower, as compared to the landraces. This suggests that modern wheat breeding practices may have led to an increased exposure to CD epitopes. On the other hand, some modern varieties and landraces have been identified that have relatively low contents of both epitopes. Such selected lines may serve as a start to breed wheat for the introduction of ‘low CD toxic’ as a new breeding trait. Large-scale culture and consumption of such varieties would considerably aid in decreasing the prevalence of CD