The Proteoglycan Biglycan Modulates Platelet Adhesion and Thrombus Formation in a GPVI-Dependent Manner

Background: Vascular injury induces the exposure of subendothelial extracellular matrix (ECM) important to serve as substrate for platelets to adhere to the injured vessel wall to avoid massive blood loss. Different ECM proteins are known to initiate platelet adhesion and activation. In atherosclerotic mice, the small, leucine-rich proteoglycan biglycan is important for the regulation of thrombin activity via heparin cofactor II. However, nothing is known about the role of biglycan for hemostasis and thrombosis under nonatherosclerotic conditions. Methods: The role of biglycan for platelet adhesion and thrombus formation was investigated using a recombinant protein and biglycan knockout mice. Results: The present study identified biglycan as important ECM protein for the adhesion and activation of platelets, and the formation of three-dimensional thrombi under flow conditions. Platelet adhesion to immobilized biglycan induces the reorganization of the platelet cytoskeleton. Mechanistically, biglycan binds and activates the major collagen receptor glycoprotein (GP)VI, because reduced platelet adhesion to recombinant biglycan was observed when GPVI was blocked and enhanced tyrosine phosphorylation in a GPVI-dependent manner was observed when platelets were stimulated with biglycan. In vivo, the deficiency of biglycan resulted in reduced platelet adhesion to the injured carotid artery and prolonged bleeding times. Conclusions: Loss of biglycan in the vessel wall of mice but not in platelets led to reduced platelet adhesion at the injured carotid artery and prolonged bleeding times, suggesting a crucial role for biglycan as ECM protein that binds and activates platelets via GPVI upon vessel injury.     

Inability of unpacked gooseneck liners to stop the sample liquid after injection with band formation (fast autosampler) into hot GC injectors

With the introduction of the fast autosampler, the rules on how to perform splitless injection should have been revisited: the fast autosampler releases the sample liquid as a band that is no longer nebulized by solvent vapors as in previous injection techniques. In empty gooseneck liners, the sample liquid is shot to the bottom of the injector and jumps around in a largely uncontrolled manner. Visual experiments showed that the liquid is partially rejected. Another portion passes by the column inlet into the column attachment region, while the last part may directly enter the column. The impact on chromatography was investigated by using a mixture of n-alkanes: the higher boiling components passing by the column entrance into the zone of the column attachment were largely lost, i.e., were discriminated against the volatile components. It was concluded that empty gooseneck liners are not suitable for injection by fast autosamplers.     

Acrylamide in a fried potato dish (rösti) from restaurants in Zurich,Switzerland

Rösti, a fried potato product, is a large contributor to acrylamide exposure locally in Switzerland. A survey of 55 dishes prepared by 51 restaurants in the city of Zurich showed that the average rösti contained 702 µg/kg acrylamide. By analysing the content of reducing sugars in the potatoes used for frying, it is shown that with simple measures, the exposure to acrylamide could easily be reduced by factor 2 or more, while even improving the culinary experience. Though rösti is a typical dish in the German-speaking areas in Switzerland, the result may be of general interest for fried potato products which are popular in large areas of Central Europe.     

Detection of desterolized sunflower oil in olive oil through isomerized Δ7-sterols

Adulteration of expensive edible oils, such as olive oil, often involves desterolized oils in order to render the adulteration undetectable. Sunflower oil contains characteristic Δ7-sterols, which are readily removed upon strong bleaching. It is shown that these Δ7-sterols do not primarily dehydrate (as do Δ5-sterols), but isomerize to Δ8(14)- and Δ14-sterols. These compounds can be analysed by LC on silica gel or GC on capillary columns with stationary phases of intermediate to high polarity.     

Food contamination by hydrocarbons from packaging materials determined by coupled LC-GC

Summary Paraffins from raw extracts of foods and packing materials were isolated by LC and directly transferred to GC, applying concurrent eluent evaporation and a loop-type interface. Paraffins from various packing materials have been characterized: sisal bags, cardboard boxes, plastic films, wax-coated paper and cardboard as well as paraffin coatings. Important food contamination was found for sisal bags, cardboard boxes, and waxcoated paper/cardboard. Contamination by paraffin coatings on cheese was surprisingly small.

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Verunreinigung von Lebensmitteln mit Kohlenwasserstoffen aus Verpackungsmaterialien und Nachweis mittels gekoppelter LC-GC

Zusammenfassung Die Paraffinfraktion aus rohen Extrakten von Lebensmitteln und Verpackungsmaterialen wurde mittels LC isoliert und durch simultane Abdampfung direkt in den GC transferiert. Typische Paraffinmuster verschiedener Verpackungsmaterialien (Sisalsäcke, Karton, Plastikfolien, Wachspapier und Paraffin) werden charakterisiert. Starke Verunreinigungen der Lebensmittel wurden bei Sisalsäcken, Kartonschachteln, Wachspapieren und Wachskarton gefunden. Die Verunreinigung von Käse durch eine Schicht Paraffin war vergleichbar gering.

     

Mineral oil contents in paper and board recycled to paperboard for food packaging

Types of paper and board fed into the recycling process to manufacture paperboard for food packaging were analysed for saturated and aromatic mineral oil hydrocarbons. The focus was on the hydrocarbons eluted from gas chromatography before n‐C₂₄, as these are relevant for migration into dry foods via the gas phase at ambient temperature. Newspapers and leaflets printed by similar techniques were identified as the predominant sources of mineral oil, whereas office paper, books and corrugated board were the starting materials of lowest mineral oil content. Paperboard produced from the latter sources would contain about five times less mineral oil than the average observed today, but the migration into food could still exceed the limit derived from the available acceptable daily intake by a factor of up to 20. On average, European newspapers produced by offset printing contained 4.1 g/kg <C₂₄ mineral oil with 21% aromatic hydrocarbons. One out of four Japanese newspapers only contained 430 mg/kg <C₂₄ saturated and less than 15 mg/kg aromatic hydrocarbons. However, the maximum migration from paperboard exclusively produced from such newspaper would still far exceed the limit. Copyright © 2010 John Wiley & Sons, Ltd.     

Taped Barrier Test for Internal Bags Used in Boxes of Recycled Paperboard: The Role of the Paperboard and Its Consequence for the Test

Internal bags with a functional barrier are a promising solution to render recycled paperboard acceptable for food packaging. Producers and users of such bags as well as control authorities need a tool to evaluate whether a bag satisfies the requirements of safety. In the previously proposed methods, the criterion focused on the permeability of the barrier layer. This neglected the influence of absorption or adsorption of the substances in the paperboard and the plastic of the bag. To take these contributions into account, it was proposed to change the criterion and use the percentage of the amount of (surrogate) substances in the recycled paperboard that passes into the food. This paper explains this, in particular how the method better reflects the reality in a pack of food. Firstly, donors should be prepared from recycled paperboard, as the behaviour differs from that of paper. Secondly, absorption into the paperboard seems to be a slow process. It was noted that freshly added surrogate substances were easily extracted by methyl tert‐butyl ether, but the extraction yield decreased during storage over some weeks. To catch this reality of the substances in the paperboard, donors need to be conditioned before use. Finally, absorption in the paperboard may depend on the concentration, which prompted a further reduction of the amounts of the surrogate substances used for testing. It turned out that usually the hydrocarbon (C17) determines the barrier efficiency; triethyl citrate is no longer used, as it was never a relevant surrogate. Copyright © 2016 John Wiley & Sons, Ltd.     

The Detection of Adulteration with Desterolized Oils

Edible oils are desterolized in order to render them “undetectable” when admixed to other oils. Such frauds remain, however, detectable by the olefinic degradation products of the sterols: the degradation products approximately have the composition of the sterols they originate from. Presence of campestatriene (degraded brassicasterol) reveals the presence of desterolized rapeseed oil. The ratio of the degradation products of sitosterol and campesterol is a sensitive indicator for desterolized sunflower, soybean, palm, or grapeseed oil in oils of low campesterol content, such as olive and walnut oil. Analyses were performed by on-line coupled LC-GC.