Discrete Organic Phosphorus Signatures are Evident in Pollutant Sources within a Lake Erie Tributary.

Phosphorus loads are strongly associated with the severity of harmful algal blooms in Lake Erie, a Great Lake situated between the United States and Canada. Inorganic and total phosphorus measurements have historically been used to estimate nonpoint and point source contributions, from contributing watersheds with organic phosphorus often neglected. Here, we used ultrahigh resolution mass spectrometry to characterize the dissolved organic matter and specifically dissolved organic phosphorus composition of several nutrient pollutant source materials and aqueous samples in a Lake Erie tributary. We detected between 23 and 313 organic phosphorus formulas across our samples, with manure samples having greater abundance of phosphorus- and nitrogen containing compounds compared to other samples. Manures also were enriched in lipids and protein-like compounds. The greatest similarities were observed between the Sandusky River and wastewater treatment plant effluent (WWTP), or the Sandusky River and agricultural edge of field samples. These sample pairs shared 84% of organic compounds and 59-73% of P-containing organic compounds, respectively. This similarity suggests that agricultural and/or WWTP sources dominate the supply of organic phosphorus compounds to the river. We identify formulas shared between the river and pollutant sources that could serve as possible markers of source contamination in the tributary.

Presumed primary cardiac mast cell tumor, pericardial effusion, and arrhythmia in a dog.

A 13-year-old female spayed border collie cross presented for pericardial effusion, arrhythmia, and a suspected cardiac mass. Echocardiogram revealed severe thickening and hypokinesis of the interventricular septum with a heterogenous, cavitated myocardium, concerning for neoplasia. Electrocardiogram revealed predominantly accelerated idioventricular rhythm with frequent periods of nonsustained ventricular tachycardia. Occasional prolonged PR intervals terminating in an aberrantly conducted QRS complex were present. These beats were postulated to represent either first-degree atrioventricular block with aberrant QRS conduction or atrioventricular dissociation. Cytology of the pericardial effusion revealed atypical, suspected neoplastic, mast cells. The patient was euthanized, and postmortem examination confirmed full-thickness infiltration of the interventricular septum by a mast cell tumor, with metastasis to the tracheobronchial lymph node and spleen. Given the anatomic location of the mass, the observed atrioventricular nodal conduction delay may represent neoplastic infiltration of the atrioventricular node. Neoplastic infiltration of the ventricle was suspected to cause the accelerated idioventricular rhythm and ventricular tachycardia. To the authors' knowledge, this is the first reported case of a primary cardiac mast cell tumor causing arrhythmia and pericardial effusion in a dog.

Recommended guidelines for submission, trimming, margin evaluation, and reporting of tumor biopsy specimens in veterinary surgical pathology.

Neoplastic diseases are typically diagnosed by biopsy and histopathological evaluation. The pathology report is key in determining prognosis, therapeutic decisions, and overall case management and therefore requires diagnostic accuracy, completeness, and clarity. Successful management relies on collaboration between clinical veterinarians, oncologists, and pathologists. To date there has been no standardized approach or guideline for the submission, trimming, margin evaluation, or reporting of neoplastic biopsy specimens in veterinary medicine. To address this issue, a committee consisting of veterinary pathologists and oncologists was established under the auspices of the American College of Veterinary Pathologists Oncology Committee. These consensus guidelines were subsequently reviewed and endorsed by a large international group of veterinary pathologists. These recommended guidelines are not mandated but rather exist to help clinicians and veterinary pathologists optimally handle neoplastic biopsy samples. Many of these guidelines represent the collective experience of the committee members and consensus group when assessing neoplastic lesions from veterinary patients but have not met the rigors of definitive scientific study and investigation. These questions of technique, analysis, and evaluation should be put through formal scrutiny in rigorous clinical studies in the near future so that more definitive guidelines can be derived.

Influence of Carbon and Microbial Community Priming on the Attenuation of Uranium in a Contaminated Floodplain Aquifer.

The capacity for subsurface sediments to sequester radionuclide contaminants, such as uranium (U), and retain them after bioremediation efforts are completed is critical to the long-term stewardship of re-mediated sites. In U bioremediation strategies, carbon amendment stimulates bioreduction of U(VI) to U(IV), immobilizing it within the sediments. Sediments enriched in natural organic matter are naturally capable of sequestering significant U, but may serve as sources to the aquifer, contributing to plume persistence. Two types of organic-rich sediments were compared to better understand U release mechanisms. Sediments that were artificially primed for U removal were retrieved from an area previously biostimulated while detrital-rich sediments were collected from a location never subject to amendment. Batch incubations demonstrated that primed sediments rapidly removed uranium from the groundwater, whereas naturally reduced sediments released a sizeable portion of U before U(VI)-reduction commenced. Column experiments confirmed that U release persisted for 65 pore volumes in naturally reduced sediments, demonstrating their sink-source behavior. Acetate addition to primed sediments shifted the microbial community from sulfate-reducing bacteria within Desulfobacteraceae to the iron-reducing Geobacteraceae and Firmicutes, associated with efficient U(VI) removal and retention, respectively. In contrast, Geobacteraceae communities in naturally reduced sediments were replaced by sequences with similarity to Pseudomonas spp. during U release, while U(VI) removal only occurred with enrichment of Firmicutes. These investigations stress the importance of characterizing zones with heterogeneous carbon pools at U-contaminated sites prior to the determination of a remedial strategy to identify areas, which may contribute to long-term sourcing of the contaminants.