An Evaluation of the Occurrence of Micronuclei and other Nuclear Abnormalities in Fishes from the Great Lakes Basin, United States

Biological markers (biomarkers) sensitive to genotoxic and mutagenic contamination in fishes are widely used to identify contamination in the aquatic environment. The fish tumors or other deformities biological use impairment (BUI) occurs at 18 of the 30 areas of concern (AOC) located in the Great Lakes basin within the United States. As each AOC evaluates this specific BUI for possible delisting, biomarkers sensitive to both genotoxic and mutagenic chemicals can be integrated as a possible criterion for delisting. The micronucleus assay identifies genotoxic contamination by observing the presence of a micronucleus (MN), along with a primary nucleus within the cellular body. Nuclear abnormalities (NA) such as notching, lobes, blebbing, and binucleation are observed from the nuclear membrane and are indicators for mutagenic contamination. The micronucleus assay was incorporated to assess genotoxic and mutagenic contamination among sites, species, and season from fish collected from 8 AOC\u27s, as well as 1 non-AOC site during the spring and fall, 2011. Micronuclei and/or NA were observed at all sites. Micronuclei were observed at differing occurrence rates among species. Brown bullhead (Ameiurus nebulosus ) expressed MN at a lower rate when compared to either largemouth bass (Micropterus salmoides) or smallmouth bass ( Micropterus dolomieu). White sucker (Catostomus commersoni ) express MN at a lower rate when compared to smallmouth bass. Nuclear abnormalities rates exactly followed these trends. Brown bullhead tended to express MN and NA at a lower rate during the fall as compared to individuals collected in the spring. Largemouth bass tended to express MN and NA at a higher rate during the spring. Moving forward, this apparent site and species effect should be considered when evaluating genotoxic and mutagenic contamination

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

An Examination of Cyanotoxins and Environmental Estrogens in the Middle and Upper Potomac River Watershed, USA

The Potomac River is a large tributary of the Chesapeake Bay. Large fish die-offs were reported in the Potomac watershed (specifically the South Branch of the Potomac) in 2002 and 2005, as well as smaller episodic events in recent years which have no clear correlation to any one pathogen or contaminant. Although a variety of pathogens have been identified (such as trematodes, myxozoans, Aeromonas hydrophila, A. salmonicida, Flavobacterium columnare , and largemouth bass virus) in recent die-offs of smallmouth bass Micropterus dolomieu, no clear cause has been derived. Additionally, reproductive endpoints were reported in smallmouth bass and likely associated with instream estrogenic compounds. There has been increasing support for estrogenic compounds associated with agricultural runoff as one of the causes. However, there are little data on the contribution from primary producers such as cyanobacteria. Harmful algal blooms are of increasing concern to human health worldwide and their effects on the aquatic community within the South Branch Potomac watershed is largely unknown. To address knowledge gaps associated with fish health in the South Branch Potomac watershed, an assessment of the temporal and spatial distribution of algal toxins and environmental estrogens was required. This dissertation addresses: 1) the spatial and temporal distribution of cyanobacterial toxins in water, periphyton, and fish tissue; 2) the transcriptional response of smallmouth bass hepatocytes and leukocytes challenged with the cyanobacterial toxin microcystin-LR; 3) the spatial and temporal distribution of environmental estrogens in water and periphyton and their association with phytoestrogen presence and cyanobacterial toxins; and 4) an assessment of reporter interference in water and periphyton samples

Linking Patterns in Endocrine-Disrupting Compounds to Storm Discharge and Yoy Smb Health in the Upper Juniata River Watershed

Population declines and disease incidence in smallmouth bass (Micropterus dolomieu) in the Susquehanna River basin have been linked to endocrine-disrupting compounds (EDCs) as a likely causative agent. Nothing is known about this link in the upper Juniat

Micronuclei and Other Erythrocyte Nuclear Abnormalities in Fishes from the Great Lakes Basin,USA

Biological markers (biomarkers) sensitive to genotoxic and mutagenic contamination in fishes are widely used to identify exposure effects in aquatic environments. The micronucleus assay was incorporated into a suite of indicators to assess exposure to genotoxic and mutagenic contamination at five Great Lakes Areas of Concern (AOCs), as well as one non-AOC (reference) site. The assay allowed enumeration of micronuclei as well as other nuclear abnormalities for both site and species comparisons. Erythrocyte abnormality data was also compared to skin and liver tumor prevalence and hepatic transcript abundance. Erythrocyte abnormalities were observed at all sites with variable occurrence and severity among sites and species. Benthic-oriented brown bullhead (Ameiurus nebulosus) and white sucker (Catostomus commersonii) expressed lower rates of erythrocyte abnormalities, but higher rates of skin and liver neoplasms, when compared to pelagicoriented largemouth bass (Micropterus salmoides) or smallmouth bass (Micropterus dolomieu) at the same site. The reduced erythrocyte abnormalities, increased transcript abundance associated with Phase I and II toxicant responsive pathways, and increased neoplastic lesions among benthic-oriented taxa may indicate the development of contaminant resistance of these species to more acute effects

Temporal and spatial variation in endocrine disrupting compounds and young-of-theyear smallmouth bass health in the upper Juniata River system

Over a 2-year time frame in summer 2016 and 2017, we quantified the dynamics of endocrine disrupting compounds (EDCs) in the upper Juniata River system. EDCs have been implicated as a likely cause of declines in recruitment and thus adult smallmouth bass (SMB) populations in the lower Juniata and Susquehanna Rivers since 2005. We studied the mainstem of the upper Juniata River (near Mapleton), and 5 other major tributaries in the drainage system. Specifically, we quantified EDC levels (estradiol equivalents, EEQ in ng/L) across a range of flow types at 9 different sites and subsequently looked at how these hydrologic conditions (e.g., peak storm flows vs. ascending flow, vs. base flows, etc.) and landscape characteristics among sites may explain the variation in EDCs. In addition, we measured EDC levels along a continuum of the Juniata River downstream of a waste water treatment plant to quantify decay patterns once entering water. Finally, at each site we collected information on young-of-the-year (YOY) SMB condition and diet. We used non-lethal gastric lavage techniques to extract diet contents and sacrificed a subset of individuals to estimate efficiency. EDC concentrations varied widely within sites at the same time, within sites at different times, among sites, and between years, but levels thus far in our surveys have not surpassed 1 ng/L, a threshold considered to be a concern for fish health. Initial analyses indicate that river discharge and flow characteristics related to storm runoff cannot explain variation in EDCs, nor have we identified landscape characteristics at 2 spatial scales that can explain variation. Thus far, we could not detect a trend in EDC concentrations downstream of the waste water treatment plant. In 2016, YOY SMB were numerous and were in excellent health, but were nearly absence during the same time in 2017. Most individuals contained at least some prey items, which on average consisted of about half aquatic prey and half terrestrial or neustonic prey. Rusty crayfish diet lacked resemblance to diet in YOY SMB. After gastric lavage, only a few fish were found to have some stomach contents remaining when dissected in the lab. Furthermore, nearly all YOY SMB fully recovered from field lavage experiences. Our study has identified levels of EDCs in the upper Juniata River systems that should be considered important for addressing ecological health in the broader Susquehanna River basin. Advancing our understanding of the dynamics of these emerging contaminants and their potential effects on smallmouth bass will require tracking and measuring specific compounds. We found gastric lavage to be a safe and effective technique to study YOY SMB feeding ecology without having to kill numerous individuals of this popular gamefish

Variability in Endocrine-Disrupting Compounds in the Upper Juniata River System

Population declines and disease incidence in smallmouth bass (Micropterus dolomieu) in the Susquehanna River basin have been linked to endocrine-disrupting compounds (EDCs) as a likely causative agent. Nothing is known about EDC dynamics in the upper Juniata River basin, and specifically how EDC patterns may vary with hydrologic conditions and landscape characteristics. We sampled water in the mainstem of the Juniata River and at 5 major tributaries across a range of discharges (e.g., peak storm flows, descending flows, base flows, etc.) and landscape characteristics over a 2-year time frame during the summers of 2016 and 2017. Samples were analyzed for EDCs measured as total estradiol equivalents (EEQ, ng/L). We also collected information on pH, dissolved oxygen, temperature, specific conductance, and total dissolved solids during each sampling event to identify possible connections between hydrologic conditions and variation in EDC concentrations. We found extremely high spatial and temporal variation in EDCs concentrations. Concentrations varied highly within sites at the same time, within sites at different times, among sites, and between years, but levels thus far have not surpassed the 1 ng/L threshold considered to be a concern for fish health. Thus far, we could not detect a trend in EDC concentrations along a continuum of the Juniata River downstream of the waste water treatment plant. Additionally, our current analyses cannot link variation in EDC concentrations to discharge, simple water quality measurements, or landuse/landcover at 2 spatial scales, but early indications suggest that EDCs are present in quantities that should be considered important for addressing ecological health in the broader Susquehanna River basin

Hepatic Gene Expression Profiling of American Kestrels (<i>Falco sparverius</i>) Exposed In Ovo to Three Alternative Brominated Flame Retardants

A number of brominated flame retardants (BFRs) have been reported to interfere with the thyroid signaling pathway and cause oxidative stress in birds, yet the underlying shifts in gene expression associated with these effects remain poorly understood. In this study, we measured hepatic transcriptional responses of 31 genes in American kestrel (Falco sparverius) hatchlings following in ovo exposure to one of three high-volume alternative BFRs: 1,2-bis(2,4,6-tribromophenoxy) ethane (BTPBE), bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH), or 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB). Hatchling kestrels exhibited shifts in the expression of genes related to oxidative stress (CYP, GSTA, SOD, and GPX1), thyroid hormone metabolism and transport (DIO1, DIO2, and TTR), lipid and protein metabolism (PPAR, HMGCR, FAB1, and LPL), and cytokine-mediated inflammation (TLR3, IL18, IRF7, STAT3, RACK1, and CEBPB). Male and female hatchlings differed in which genes were differentially expressed, as well as the direction of the effect (up- vs. downregulation). These results build upon our previous findings of increased oxidative stress and disrupted thyroid signaling pathway in the same hatchlings. Furthermore, our results indicate that inflammatory responses appear to occur in female hatchlings exposed to BTBPE and EHTBB in ovo. Gene expression analysis revealed multiple affected pathways, adding to the growing evidence that sublethal physiological effects are complex and are a concern for birds exposed to BTBPE, EHTBB, or TBPH in ovo