Filtering impacts of larval and sessile zebra mussels (Dreissena polymorpha) in western Lake Erie

We assessed the feeding biology of veliger larvae of the introduced zebra mussel (Dreissena polymorpha Pallas) in laboratory experiments using inert microspheres as food analogues. Mean clearance rate on 2.87-μm beads ranged between 247 and 420 μL veliger-1 day-1. Clearance rate was unrelated to bead concentration up to 100 beads μL-1, but was positively correlated with veliger shell length. Clearance rates of Dreissena veligers are within the range of those reported for marine bivalve veligers of similar size and for herbivorous Great Lakes microzooplankton, but are orders of magnitude lower than those of settled, conspecific adults. The impact of settled zebra mussel grazing activities on phytoplankton stocks may be up to 1162 times greater than that exerted by veliger populations in western Lake Erie. Based on 1990 size-frequency distributions and associated literature-derived clearance rates, reef-associated Dreissena populations in western Lake Erie (mean depth ∼7 m) possess a tremendous potential to filter the water column (up to 132 m3 m-2 day-1) and redirect energy from pelagic to benthic foodwebs. Preliminary analyses indicate that chlorophyll a concentration is strongly depleted (\u3c1 μg L-1) above Dreissena beds in western Lake Erie. © 1992 Springer-Verlag

First-in-man mesenchymal stem cells for radiation-induced xerostomia (MESRIX): study protocol for a randomized controlled trial

BACKGROUND: Salivary gland hypofunction and xerostomia are major complications following radiotherapy for head and neck cancer and may lead to debilitating oral disorders and impaired quality of life. Currently, only symptomatic treatment is available. However, mesenchymal stem cell (MSC) therapy has shown promising results in preclinical studies. Objectives are to assess safety and efficacy in a first-in-man trial on adipose-derived MSC therapy (ASC) for radiation-induced xerostomia. METHODS: This is a single-center, phase I/II, randomized, placebo-controlled, double-blinded clinical trial. A total of 30 patients are randomized in a 1:1 ratio to receive ultrasound-guided, administered ASC or placebo to the submandibular glands. The primary outcome is change in unstimulated whole salivary flow rate. The secondary outcomes are safety, efficacy, change in quality of life, qualitative and quantitative measurements of saliva, as well as submandibular gland size, vascularization, fibrosis, and secretory tissue evaluation based on contrast-induced magnetic resonance imaging (MRI) and core-needle samples. The assessments are performed at baseline (1 month prior to treatment) and 1 and 4 months following investigational intervention. DISCUSSION: The trial is the first attempt to evaluate the safety and efficacy of adipose-derived MSCs (ASCs) in patients with radiation-induced xerostomia. The results may provide evidence for the effectiveness of ASC in patients with salivary gland hypofunction and xerostomia and deliver valuable information for the design of subsequent trials. TRIAL REGISTRATION: EudraCT, Identifier: 2014-004349-29. Registered on 1 April 2015. ClinicalTrials.gov, Identifier: NCT02513238. First received on 2 July 2015. The trial is prospectively registered. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13063-017-1856-0) contains supplementary material, which is available to authorized users

Competition in natural populations of Daphnia

I investigated the competitive relationships between two species of Daphnia, D. galeata and D. cucullata, and their interspecific hybrid. The term hemispecific competition was introduced to describe competition between parental species and hybrids. In eutrophic Tjeukemeer both parental species were found to compete with the hybrid, whereas competition between D. galeata and D. cucullata seemed limited. Although the effect of competition on life history traits of daphnids may be profound, the influence of the competitors on the seasonal dynamics of the Daphnia species seems limited. [KEYWORDS: COEXISTENCE, HYBRID, COMPETITION, DAPHNIA, HEMISPECIFIC]