Biodistribution of a Nonpeptidic Fluorescent Endothelin a Receptor Imaging Probe

Biodistribution studies are essential for understanding the biologic behavior of novel fluorochrome-based molecular imaging agents. In this study, the biodistribution of a recently developed fluorescent imaging probe with high affinity to the endothelin A (ET A ) receptor was evaluated by fluorescence reflectance imaging (FRI). CD-1 mice were injected with 2 nmol of the probe intravenously and sacrificed at various time points. Tissue samples of the heart, spleen, lung, kidneys, liver, brain, and muscle were removed and imaged by FRI. Initially, the signal intensity (SI) was highest in lung, kidney, and liver tissue, followed by the heart, whereas spleen, muscle, and brain showed the lowest SI. In the kidneys, the SI decreased rapidly. In the heart, an initial SI increase was observed, followed by SI attenuation, whereas in the lung, the SI steadily increased. Competition experiments showed a significant ( p #x003C; .005) degree of specific binding in the heart, with a reduction in SI of > 50%. In conclusion, FRI allows us to perform biodistribution studies of novel fluorescent tracers. The developed imaging probe can be exploited to image ET A receptor expression ideally 30 minutes to 3 hours after injection

Effect of round goby (Neogobius melanostomus) invasion on blue mussel (Mytilus edulis trossulus) population and winter diet of the long-tailed duck (Clangula hyemalis)

The invasive round goby has established a viable population within 9 years of its first introduction to Lithuanian coastal waters (SE Baltic Sea). During its expansion phase, abundances increased 23-fold, which led to the near complete eradication of its main prey, the blue mussel, at < 20 m depth. The round goby population showed a stabilizing trend after blue mussel biomass was depleted; however, their abundance has not declined. The round goby feeds efficiently on newly settled mollusks, causing a severe constraint for blue mussel recovery. Changes in blue mussel availability and size structure induced a dietary shift in wintering long-tailed duck towards fish prey. An energetically dense food source sustains a good body condition in long-tailed ducks, however the change in trophic position (from 3.1 to 4.3 trophic level) suggests the potential for a reduction in their carrying capacity. Results from this study also show that coastal habitats with low and unpredictable population dynamics of blue mussel become less attractive wintering sites for long-tailed duck in the Baltic Sea. We also document a cascading effect of invasive species in the food web