Solitary pedunculated multicystic viral plaque associated with canine papillomavirus 18 in a British Bulldog.

A pedunculated exophytic mass developed on the rump of a dog. Fine-needle aspiration revealed keratin debris suggestive of a follicular tumor. However, histology revealed a pigmented viral plaque that contained numerous keratin-filled cystic cavities. Canine papillomavirus 18 DNA sequences were detected in the lesion. Viral plaques are typically multiple sessile lesions of dogs. A viral plaque appearing as a solitary exophytic keratin-filled mass has not been reported previously, to our knowledge. The novel clinical findings in this case expand the ways that viral plaques may appear in dogs. In addition, the histologic findings represent a novel pathologic entity of dogs. Given that canine viral plaques can be progressive, and dogs typically develop numerous plaques, it is important to differentiate between a viral plaque and a hair follicle tumor.

Bioaccumulation kinetics and internal distribution of the fission products radiocaesium and radiostrontium in an estuarine crab.

Crab has been designated by the ICRP as one of twelve reference/model organisms for understanding the impacts of radionuclide releases on the biosphere. However, radionuclide-crab interaction data are sparse compared with other reference organisms (e.g. deer, earthworm). This study used an estuarine crab (Paragrapsus laevis) to investigate the contribution of water, diet and sediment sources to radionuclide (134Cs and 85Sr) bioaccumulation kinetics using live-animal radiotracing. The distribution of each radionuclide within the crab tissues was determined using dissection, whole-body autoradiography and synchrotron X-ray Fluorescence Microscopy (XFM). When moulting occurred during exposure, it caused significant increases in 85Sr bioaccumulation and efflux of 134Cs under constant aqueous exposure. Dietary assimilation efficiencies were determined as 55 ± 1% for 134Cs and 49 ± 3% for 85Sr. 85Sr concentrated in gonads more than other organs, resulting in proportionally greater radiation dose to the reproductive organs and requires further investigation. 134Cs was found in most soft tissues and was closely associated with S and K. Biodynamic modelling suggested that diet accounted for 90-97% of whole-body 137Cs, while water accounted for 59-81% of 90Sr. Our new data on crab, as a representative invertebrate, improves understanding of the impacts of planned or accidental releases of fission radionuclides on marine ecology.

Initial data on adsorption of Cs and Sr to the surfaces of microplastics with biofilm.

The adsorption of radiocesium and radiostrontium onto a range of natural materials has been well quantified, but not for the new media of environmental plastics, which may have enhanced adsorption due to surface-weathering and development of biofilms. Microplastic samples were deployed in freshwater, estuarine and marine conditions, then characterised using infrared spectroscopy to document changes to the plastic surface (vs interior). Synchrotron elemental mapping data revealed surfaces that were well-covered by accumulation of reactive water solutes and sulphur, but, in contrast, had highly discrete coverage of elements such as Fe and Ti, indicating adhered mineral/clay-associated agglomerates that may increase overall adsorption capacity. Plastics that had been deployed for nearly five months adsorbed radionuclides in both freshwater and estuarine conditions with the highest Kd for cesium (Cs) in freshwater (80 ml g-1) and lowest for strontium (Sr) in estuarine conditions (5 ml g-1). The degree of Cs and Sr adsorption onto plastics appears to be approximately 2-3 orders of magnitude lower than for sediment reference values. While lower than for sediments, adsorption occurred on all samples and may indicate a significant radionuclide reservoir, given that plastics are relatively buoyant and mobile in water regimes, and are increasing in global aquatic systems.