Permeability of the salmon (Oncorhynchus tshawytscha) posterior intestine in vivo to two hydrophilic markers

This study characterised the permeability of the salmonid posterior intestine in vivo, to two hydrophilic markers of different molecular weight, both in the presence and absence of sodium deoxycholate (SDA), and determined the influence of mucosal secretions. The posterior intestine of chinook salmon was cannulated with a balloon catheter and the lumen infused with a solution of fluorescein and ¹⁴C-mannitol. In treated fish, the solution also contained 5.0 mmol · l⁻¹ SDA. Blood samples from the dorsal aorta were taken at regular time intervals over 3 h. Clearances and volumes of distribution were assessed by intravenous administration of the markers to another group of fish. In the absence of SDA, low permeabilities were recorded for both markers; however, permeabilities for both were significantly greater in the treated groups. Both solutes had volumes of distribution similar to values reported elsewhere. Metabolism of fluorescein by the liver resulted in its plasma clearance. In contrast, elimination of mannitol was negligible during the study period, probably due to the lowered glomerular filtration rates observed in sea water adapted fish. Compared to in vitro investigations, in vivo mucus secretions were significantly lower and solute delivery across the epithelium was higher. Results from these in vivo investigations have implications for the oral delivery of peptides to salmonids. Accepted: 6 August 1998     

Restoration scenario planning at a Spanish quarry can be informed by assessing ecosystem services

We carried out an ecosystem service (ES) assessment at Soto de Pajares, a 400 ha active gravel quarry site located close to protected areas in the southeast of the Community of Madrid, Spain. The currently approved restoration plan is for quarry‐made excavations to be restored back to agricultural land. However, the site has been identified as being important for nature, so different restoration strategies should be considered. To better understand how these compare in terms of ES provision, which had not previously been done at mineral extraction sites in Spain, we used an established toolkit: the Toolkit for Ecosystem Service Site‐based Assessments (TESSA). We compared the agriculture‐focused restoration plan and two nature‐focused alternative scenarios, one without public access (conservation scenario) and the other with public access (compromise scenario). Monetary estimations of the value of agricultural production, climate change mitigation, and recreation were calculated in three scenarios. Results indicated that the compromise scenario provided the greatest annual value (€91,409), mainly due to its potential visitors, surpassing both agricultural (€68,504) and conservation (€48,556) scenarios. Considering the higher costs associated with restoring sites to agricultural production, nature conservation may be an attractive option for extraction companies. The use of TESSA at this site has provided valuable information to quarry managers to help guide their decision‐making.     

Collagen Can Selectively Trigger a Platelet Secretory Phenotype via Glycoprotein VI

Platelets are not only central actors of hemostasis and thrombosis but also of other processes including inflammation, angiogenesis, and tissue regeneration. Accumulating evidence indicates that these “non classical” functions of platelets do not necessarily rely on their well-known ability to form thrombi upon activation. This suggests the existence of non-thrombotic alternative states of platelets activation. We investigated this possibility through dose-response analysis of thrombin- and collagen-induced changes in platelet phenotype, with regards to morphological and functional markers of platelet activation including shape change, aggregation, P-selectin and phosphatidylserine surface expression, integrin activation, and release of soluble factors. We show that collagen at low dose (0.25 µg/mL) selectively triggers a platelet secretory phenotype characterized by the release of dense- and alpha granule-derived soluble factors without causing any of the other major platelet changes that usually accompany thrombus formation. Using a blocking antibody to glycoprotein VI (GPVI), we further show that this response is mediated by GPVI. Taken together, our results show that platelet activation goes beyond the mechanisms leading to platelet aggregation and also includes alternative platelet phenotypes that might contribute to their thrombus-independent functions.