Publications by authors named "J Robert Harkness"

276 Publications

Diurnal changes in perineuronal nets and parvalbumin neurons in the rat medial prefrontal cortex.

Brain Struct Funct 2021 Feb 14. Epub 2021 Feb 14.

Department of Integrative Physiology and Neuroscience, Washington State University Vancouver, Washington, 98686, USA.

Perineuronal nets (PNNs) surrounding fast-spiking, parvalbumin (PV) interneurons provide excitatory:inhibitory balance, which is impaired in several disorders associated with altered diurnal rhythms, yet few studies have examined diurnal rhythms of PNNs or PV cells. We measured the intensity and number of PV cells and PNNs labeled with Wisteria floribunda agglutinin (WFA) and also the oxidative stress marker 8-oxo-deoxyguanosine (8-oxo-dG) in rat prelimbic medial prefrontal cortex (mPFC) at Zeitgeber times (ZT) ZT0 (lights-on, inactive phase), ZT6 (mid-inactive phase), ZT12 (lights-off, active phase), and ZT18 (mid-active phase). Relative to ZT0, the intensities of PNN and PV labeling were increased in the dark (active) phase compared with the light (inactive) phase. The intensity of 8-oxo-dG was decreased from ZT0 at all times (ZT6,12,18). We also measured GAD 65/67 and vGLUT1 puncta apposed to PV cells with and without PNNs. There were more excitatory puncta on PV cells with PNNs at ZT18 vs. ZT6, but no changes in PV cells without PNNs and no changes in inhibitory puncta. Whole-cell slice recordings in fast-spiking (PV) cells with PNNs showed an increased ratio of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor:N-methyl-D-aspartate receptor (AMPA: NMDA) at ZT18 vs. ZT6. The number of PV cells and PV/PNN cells containing orthodenticle homeobox 2 (OTX2), which maintains PNNs, showed a strong trend toward an increase from ZT6 to ZT18. Diurnal fluctuations in PNNs and PV cells are expected to alter cortical excitatory:inhibitory balance and provide new insights into treatments for diseases impacted by disturbances in sleep and circadian rhythms.
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http://dx.doi.org/10.1007/s00429-021-02229-4DOI Listing
February 2021

Early B-cell Factor 3-Related Genetic Disease Can Mimic Urofacial Syndrome.

Kidney Int Rep 2020 Oct 14;5(10):1823-1827. Epub 2020 Jul 14.

Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester, UK.

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http://dx.doi.org/10.1016/j.ekir.2020.07.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7569699PMC
October 2020

Endocrine disrupting activities and geochemistry of water resources associated with unconventional oil and gas activity.

Sci Total Environ 2020 Dec 8;748:142236. Epub 2020 Sep 8.

Department of Obstetrics, Gynecology and Women's Health, University of Missouri, Columbia, MO 65211, USA. Electronic address:

The rise of hydraulic fracturing and unconventional oil and gas (UOG) exploration in the United States has increased public concerns for water contamination induced from hydraulic fracturing fluids and associated wastewater spills. Herein, we collected surface and groundwater samples across Garfield County, Colorado, a drilling-dense region, and measured endocrine bioactivities, geochemical tracers of UOG wastewater, UOG-related organic contaminants in surface water, and evaluated UOG drilling production (weighted well scores, nearby well count, reported spills) surrounding sites. Elevated antagonist activities for the estrogen, androgen, progesterone, and glucocorticoid receptors were detected in surface water and associated with nearby shale gas well counts and density. The elevated endocrine activities were observed in surface water associated with medium and high UOG production (weighted UOG well score-based groups). These bioactivities were generally not associated with reported spills nearby, and often did not exhibit geochemical profiles associated with UOG wastewater from this region. Our results suggest the potential for releases of low-saline hydraulic fracturing fluids or chemicals used in other aspects of UOG production, similar to the chemistry of the local water, and dissimilar from defined spills of post-injection wastewater. Notably, water collected from certain medium and high UOG production sites exhibited bioactivities well above the levels known to impact the health of aquatic organisms, suggesting that further research to assess potential endocrine activities of UOG operations is warranted.
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http://dx.doi.org/10.1016/j.scitotenv.2020.142236DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7772064PMC
December 2020

Transcatheter mitral valve in ring, hazards of long anterior mitral leaflet and 3-dimensional rings.

Catheter Cardiovasc Interv 2021 Feb 31;97(2):353-358. Epub 2020 Aug 31.

Intermountain Heart Institute, Salt Lake City, Utah.

Objectives: The purpose of this study was to define anterior mitral leaflet (AML) length and mitral ring characteristics associated with LVOT obstruction and PVL following MViR.

Background: Transcatheter Mitral Valve in Ring (MViR) procedural complications including parvalvular leak (PVL) and left ventricular outflow tract (LVOT) obstruction are frequent.

Methods: Clinical records, computer tomographic scans (CTs) and echocardiograms of consecutive MViR patients were retrospectively reviewed for anterior mitral leaflet length, CT-simulated neoLVOT, and aortomitral angle among patients with and without MViR-induced LVOT obstruction. Acute and 1-year outcomes are described.

Results: Twenty-two patients underwent MViR. Technical success was achieved in 13/22 (57.1%) patients, limited by paravalvular regurgitation requiring second transcatheter heart valves (THVs) in seven patients. Second valves were needed in 6/11 (54.5%) patients with 3-dimensional rings but 1/11 (9.1%, p = .06) of patients with planar rings. Procedure success at 30 days was achieved in 20/22 (90.9%) patients. There were no procedural, in-hospital, or 30-day deaths. Two patients developed significant LVOT obstruction, one managed with urgent surgery and one with elective alcohol septal ablation. Anterior mitral leaflets were longer among the two patients with LVOT obstruction than the 20 patients who did not develop LVOT obstruction when measured by TEE (30 mm vs. 21 mm, p = .009) or by CT (29 mm vs. 22 mm, p = .026).

Conclusions: AML >25 mm increases the risk of MViR induced LVOT obstruction. PVL is common, particularly in 3-dimensional rings which can be managed with a second THV.
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http://dx.doi.org/10.1002/ccd.29232DOI Listing
February 2021

Concomitant marked decline in prevalence of SARS-CoV-2 and other respiratory viruses among symptomatic patients following public health interventions in Australia: data from St Vincent's Hospital and associated screening clinics, Sydney, NSW.

Clin Infect Dis 2020 Aug 25. Epub 2020 Aug 25.

St Vincent's Hospital, Sydney, Australia.

Our Australian hospital tested almost 22,000 symptomatic people over 11 weeks for SARS-CoV-2 in a multiplex PCR assay. Following travel bans and physical distancing, SARS-CoV-2 and other respiratory viruses diagnoses fell dramatically. Increasing rhinovirus diagnoses as social control measures were relaxed may indirectly indicate an elevated risk of COVID-19 resurgence.
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http://dx.doi.org/10.1093/cid/ciaa1256DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7499558PMC
August 2020

Cocaine memory reactivation induces functional adaptations within parvalbumin interneurons in the rat medial prefrontal cortex.

Addict Biol 2020 Aug 4:e12947. Epub 2020 Aug 4.

Neuroscience Graduate Program, University of Wyoming, Laramie, Wyoming, USA.

Substance use disorder is a complex disease created in part by maladaptive learning and memory mechanisms following repeated drug use. Exposure to drug-associated stimuli engages prefrontal cortex circuits, and dysfunction of the medial prefrontal cortex (mPFC) is thought to underlie drug-seeking behaviors. Growing evidence supports a role for parvalbumin containing fast-spiking interneurons (FSI) in modulating prefrontal cortical microcircuit activity by influencing the balance of excitation and inhibition, which can influence learning and memory processes. Most parvalbumin FSIs within layer V of the prelimbic mPFC are surrounded by specialized extracellular matrix structures called perineuronal nets (PNN). Previous work by our group found that cocaine exposure altered PNN-surrounded FSI function, and pharmacological removal of PNNs reduced cocaine-seeking behavior. However, the role of FSIs and associated constituents (parvalbumin and PNNs) in cocaine-related memories was not previously explored and is still unknown. Here, we found that reactivation of a cocaine conditioned place preference memory produced changes in cortical PNN-surrounded parvalbumin FSIs, including decreased parvalbumin intensity, increased parvalbumin cell axis diameter, decreased intrinsic excitability, and increased excitatory synaptic input. Further investigation of intrinsic properties revealed changes in the interspike interval, membrane capacitance, and afterhyperpolarization recovery time. Changes in these specific properties suggest an increase in potassium-mediated currents, which was validated with additional electrophysiological analysis. Collectively, our results indicate that cocaine memory reactivation induces functional adaptations in PNN-surrounded parvalbumin neurons, which likely alters cortical output to promote cocaine-seeking behavior.
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http://dx.doi.org/10.1111/adb.12947DOI Listing
August 2020

A close shave? Performance of P2/N95 respirators in healthcare workers with facial hair: results of the BEARDS (BEnchmarking Adequate Respiratory DefenceS) study.

J Hosp Infect 2020 Apr 21;104(4):529-533. Epub 2020 Jan 21.

St Vincent's Hospital, Sydney, Australia. Electronic address:

P2/N95 filtering face piece respirators (FFRs) protect healthcare workers (HCWs) from airborne infections. This study assessed the impact of facial hair on quantitative respirator fit in 105 male HCWs, of whom 38 were clean shaven, and assessed the prevalence of male facial hair at the study facility. Only 34 (32%) male HCWs overall achieved an adequate FFR fit, including 47% of clean-shaven men. No full-bearded HCWs achieved a fit. Adequate respirator fit decreased significantly with increasing facial hair (P<0.01 for trend). Facial hair was present on 49% of male employees. This study supports quantitative fit testing prior to P2/N95 respirator use.
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http://dx.doi.org/10.1016/j.jhin.2020.01.006DOI Listing
April 2020

Transcatheter Aortic Valve-in-Valve Replacement for Degenerated Stentless Bioprosthetic Aortic Valves: Results of a Multicenter Retrospective Analysis.

JACC Cardiovasc Interv 2019 07;12(13):1217-1226

Intermountain Heart Institute, Salt Lake City, Utah. Electronic address:

Objectives: The purpose of this study was to evaluate the safety and efficacy of valve-in-valve (ViV) transcatheter aortic valve replacement (TAVR) for stentless bioprosthetic aortic valves (SBAVs) and to identify predictors of adverse events.

Background: ViV TAVR in SBAVs is associated with unique technical challenges and risks.

Methods: Clinical records and computer tomographic scans were retrospectively reviewed for procedural complications, predictors of coronary obstruction, mortality, and echocardiographic results.

Results: Among 66 SBAV patients undergoing ViV TAVR, mortality was 2 of 66 patients (3.0%) at 30 days and 5 of 52 patients (9.6%) at 1 year. At 1 year, left ventricular end-systolic dimension was decreased versus baseline (median [interquartile range (IQR)]: 3.0 [2.6 to 3.6] cm vs. 3.7 [3.2 to 4.4] cm; p < 0.001). Coronary occlusion in 6 of 66 procedures (9.1%) resulted in myocardial infarction in 2 of 66 procedures (3.0%). Predictors of coronary occlusion included subcoronary implant technique compared with full root replacement (6 of 31, 19.4% vs. 0 of 28, 0%; p = 0.01), short simulated radial valve-to-coronary distance (median [IQR]: 3.4 [0.0 to 4.6] mm vs. 4.6 [3.2 to 6.2] mm; p = 0.016), and low coronary height (7.8 [5.8 to 10.0] mm vs. 11.6 [8.7 to 13.9] mm; p = 0.003). Coronary arteries originated <10 mm above the valve leaflets in 34 of 97 unobstructed coronary arteries (35.1%).

Conclusions: TAVR in SBAVs is frequently associated with high-risk coronary anatomy but can be performed with a low risk of death and myocardial infarction, resulting in favorable ventricular remodeling. A subcoronary surgical approach is associated with an increased risk of coronary obstruction.
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http://dx.doi.org/10.1016/j.jcin.2019.05.022DOI Listing
July 2019

Evaluation of the EasyScreen Protozoan Detection Kit for the diagnosis of Entamoeba histolytica.

Pathology 2019 Jun 7;51(4):426-428. Epub 2019 May 7.

Division of Microbiology, Sydpath, St Vincent's Hospital, Darlinghurst, NSW, Australia.

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http://dx.doi.org/10.1016/j.pathol.2019.01.012DOI Listing
June 2019

Origin of Flowback and Produced Waters from Sichuan Basin, China.

Environ Sci Technol 2018 12 26;52(24):14519-14527. Epub 2018 Nov 26.

Nicholas School of the Environment , Duke University , Durham , North Carolina 27708 , United States.

Shale gas extraction through hydraulic fracturing and horizontal drilling is increasing in China, particularly in Sichuan Basin. Production of unconventional shale gas with minimal environmental effects requires adequate management of wastewater from flowback and produced water (FP water) that is coextracted with natural gas. Here we present, for the first time, inorganic chemistry and multiple isotope (oxygen, hydrogen, boron, strontium, radium) data for FP water from 13 shale gas wells from the Lower Silurian Longmaxi Formation in the Weiyuan gas field, as well as produced waters from 35 conventional gas wells from underlying (Sinian, Cambrian) and overlying (Permian, Triassic) formations in Sichuan Basin. The chemical and isotope data indicate that the formation waters in Sichuan Basin originated from relics of different stages of evaporated seawater modified by water-rock interactions. The FP water from shale gas wells derives from blending of injected hydraulic fracturing water and entrapped saline (Cl ∼ 50,000 mg/L) formation water. Variations in the chemistry, δO, δB, and Sr/Sr of FP water over time indicate that the mixing between the two sources varies with time, with a contribution of 75% (first 6 months) to 20% (>year) of the injected hydraulic fracturing water in the blend that compose the FP water. Mass-balance calculation suggests that the returned hydraulic fracturing water consisted of 28-49% of the volume of the injected hydraulic fracturing water, about a year after the initial hydraulic fracturing. We show differential mobilization of Na, B, Sr, and Li from the shale rocks during early stages of operation, which resulted in higher Na/Cl, B/Cl, Li/Cl, and Sr/Sr and lower δB of the FP water during early stages of FP water formation relative to the original saline formation water recorded in late stages FP water. This study provides a geochemical framework for characterization of formation waters from different geological strata, and thus the ability to distinguish between different sources of oil and gas wastewater in Sichuan Basin.
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http://dx.doi.org/10.1021/acs.est.8b04345DOI Listing
December 2018

Sleep disruption elevates oxidative stress in parvalbumin-positive cells of the rat cerebral cortex.

Sleep 2019 01;42(1)

Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Spokane, WA.

We used a novel automated sleep disruption (SD) apparatus to determine the impact of SD on sleep and molecular markers of oxidative stress in parvalbumin (PV) neurons in the rat prefrontal cortex (PFC). Rats were subjected to two 6 hr SD sessions from zeitgeber time (ZT) 0 to ZT6, one by the gentle handling method and the other by an automated agitator running the length of the rat's home cage floor (a novel SD method). The same rats were later subjected to a 12 hr SD session from ZT0 to ZT12. Sleep was disrupted with both methods, although rats slept less during gentle handling than during the automated condition. Immediately after both SD sessions, rats displayed compensatory sleep characterized by elevated slow-wave activity. We measured in the prelimbic prefrontal cortex (prelimbic PFC; 6 and 12 hr SD) and orbital frontal cortex (12 hr SD) the intensity of the oxidative stress marker, 8-oxo-2'-deoxyguanosine (8-oxo-dG) as well as the staining intensity of PV and the PV cell-associated perineuronal net marker, Wisteria floribunda agglutinin (WFA). In the prelimbic PFC, 6 hr SD increased the intensity of 8-oxo-dG, PV, and WFA. After 12 hr SD, the intensity of 8-oxo-dG was elevated in all neurons. PV intensity was elevated only in neurons colabeled with 8-oxo-dG or WFA, and no changes were found in WFA intensity. We conclude that in association with SD-induced sleep drive, PV neurons in the prelimbic PFC exhibit oxidative stress.
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http://dx.doi.org/10.1093/sleep/zsy201DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6335871PMC
January 2019

Consumption of a High-Fat Diet Alters Perineuronal Nets in the Prefrontal Cortex.

Neural Plast 2018 23;2018:2108373. Epub 2018 Apr 23.

Neuroscience Program, University of Wyoming, Laramie, WY 82071, USA.

A key factor in the development of obesity is the overconsumption of fatty foods, which, in addition to facilitating weight gain, alters neuronal structures within brain reward circuitry. Our previous work demonstrates that sustained consumption of a high-fat diet (HFD) attenuates spine density in the prefrontal cortex (PFC). Whether HFD promotes structural adaptation among inhibitory cells of the PFC is presently unknown. One structure of interest is the perineuronal net (PNN), a specialized extracellular matrix surrounding, primarily, parvalbumin-containing GABAergic interneurons. PNNs contribute to synaptic stabilization, protect against oxidative stress, regulate the ionic microenvironment within cells, and modulate regional excitatory output. To examine diet-induced changes in PNNs, we maintained rats on one of three dietary conditions for 21 days: ad libitum chow, ad libitum 60% high fat (HF-AL), or limited-access calorically matched high fat (HF-CM), which produced no significant change in weight gain or adiposity with respect to chow controls. The PNN "number" and intensity were then quantified in the prelimbic (PL-PFC), infralimbic (IL-PFC), and ventral orbitofrontal cortex (OFC) using agglutinin (WFA). Our results demonstrated that fat exposure, independent of weight gain, induced a robust decrease in the PNN intensity in the PL-PFC and OFC and a decrease in the PNN number in the OFC.
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http://dx.doi.org/10.1155/2018/2108373DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5937429PMC
December 2018

Hydrocarbon-Rich Groundwater above Shale-Gas Formations: A Karoo Basin Case Study.

Ground Water 2018 03 6;56(2):204-224. Epub 2018 Feb 6.

Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708.

Horizontal drilling and hydraulic fracturing have enhanced unconventional hydrocarbon recovery but raised environmental concerns related to water quality. Because most basins targeted for shale-gas development in the USA have histories of both active and legacy petroleum extraction, confusion about the hydrogeological context of naturally occurring methane in shallow aquifers overlying shales remains. The Karoo Basin, located in South Africa, provides a near-pristine setting to evaluate these processes, without a history of conventional or unconventional energy extraction. We conducted a comprehensive pre-industrial evaluation of water quality and gas geochemistry in 22 groundwater samples across the Karoo Basin, including dissolved ions, water isotopes, hydrocarbon molecular and isotopic composition, and noble gases. Methane-rich samples were associated with high-salinity, NaCl-type groundwater and elevated levels of ethane, He, and other noble gases produced by radioactive decay. This endmember displayed less negative δ C-CH and evidence of mixing between thermogenic natural gases and hydrogenotrophic methane. Atmospheric noble gases in the methane-rich samples record a history of fractionation during gas-phase migration from source rocks to shallow aquifers. Conversely, methane-poor samples have a paucity of ethane and He, near saturation levels of atmospheric noble gases, and more negative δ C-CH ; methane in these samples is biogenic and produced by a mixture of hydrogenotrophic and acetoclastic sources. These geochemical observations are consistent with other basins targeted for unconventional energy extraction in the USA and contribute to a growing data base of naturally occurring methane in shallow aquifers globally, which provide a framework for evaluating environmental concerns related to unconventional energy development (e.g., stray gas).
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http://dx.doi.org/10.1111/gwat.12637DOI Listing
March 2018

Pre-drill Groundwater Geochemistry in the Karoo Basin, South Africa.

Ground Water 2018 03 30;56(2):187-203. Epub 2018 Jan 30.

Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708.

Enhanced production of unconventional hydrocarbons in the United States has driven interest in natural gas development globally, but simultaneously raised concerns regarding water quantity and quality impacts associated with hydrocarbon extraction. We conducted a pre-development assessment of groundwater geochemistry in the critically water-restricted Karoo Basin, South Africa. Twenty-two springs and groundwater samples were analyzed for major dissolved ions, trace elements, water stable isotopes, strontium and boron isotopes, hydrocarbons and helium composition. The data revealed three end-members: a deep, saline groundwater with a sodium-chloride composition, an old, deep freshwater with a sodium-bicarbonate-chloride composition and a shallow, calcium-bicarbonate freshwater. In a few cases, we identified direct mixing of the deep saline water and shallow groundwater. Stable water isotopes indicate that the shallow groundwater was controlled by evaporation in arid conditions, while the saline waters were diluted by apparently fossil meteoric water originated under wetter climatic conditions. These geochemical and isotopic data, in combination with elevated helium levels, suggest that exogenous fluids are the source of the saline groundwater and originated from remnant seawater prior to dilution by old meteoric water combined with further modification by water-rock interactions. Samples with elevated methane concentrations (>14 ccSTP/kg) were strongly associated with the sodium-chloride water located near dolerite intrusions, which likely provide a preferential pathway for vertical migration of deeply sourced hydrocarbon-rich saline waters to the surface. This pre-drill evaluation indicates that the natural migration of methane- and salt-rich waters provides a source of geogenic contamination to shallow aquifers prior to shale gas development in the Karoo Basin.
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http://dx.doi.org/10.1111/gwat.12635DOI Listing
March 2018

Manganese redox buffering limits arsenic release from contaminated sediments, Union Lake, New Jersey.

Appl Geochem 2017 Feb 11;77:24-30. Epub 2016 Oct 11.

Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964.

The sediments of Union Lake in Southern New Jersey are contaminated with arsenic released from the Vineland Chemical Company Superfund site 11 km upstream. Seasonal anoxia has been shown to release arsenic from sediments to similar lakes; this process was hypothesized as a major arsenic source to Union Lake. Data indicate, however, that releases of arsenic to bottom waters from the sediments or from pore waters within the sediments are relatively minor: bottom water arsenic concentrations reached ~30 ppb (~12 μM) at most, representing <13% of the dissolved arsenic content of the lake. Manganese concentrations increase more quickly and to higher levels than arsenic and iron concentrations; maximum [Mn]= ~13 ppm (~250 μM), maximum [Fe] = ~6 ppm (~120 μM). Incubation experiments support the hypothesis that manganese acts as a redox buffer and prevents large arsenic releases. Under the observed conditions, little of the arsenic in the water column is from contaminated sediment. This study also suggests that arsenic release from sediment to lake water may be more important in lakes that remain anoxic more continuously.
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http://dx.doi.org/10.1016/j.apgeochem.2016.10.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5726284PMC
February 2017

Naturally Occurring versus Anthropogenic Sources of Elevated Molybdenum in Groundwater: Evidence for Geogenic Contamination from Southeast Wisconsin, United States.

Environ Sci Technol 2017 Nov 19;51(21):12190-12199. Epub 2017 Oct 19.

Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States.

Molybdenum (Mo) is an essential trace nutrient but has negative health effects at high concentrations. Groundwater typically has low Mo (<2 μg/L), and elevated levels are associated with anthropogenic contamination, although geogenic sources have also been reported. Coal combustion residues (CCRs) are enriched in Mo, and thus present a potential anthropogenic contamination source. Here, we use diagnostic geochemical tracers combined with groundwater residence time indicators to investigate the sources of Mo in drinking-water wells from shallow aquifers in a region of widespread CCR disposal in southeastern Wisconsin. Samples from drinking-water wells were collected in areas near and away from known CCR disposal sites, and analyzed for Mo and inorganic geochemistry indicators, including boron and strontium isotope ratios, along with groundwater tritium-helium and radiogenic He in-growth age-dating techniques. Mo concentrations ranged from <1 to 149 μg/L. Concentrations exceeding the U.S. Environmental Protection Agency health advisory of 40 μg/L were found in deeper, older groundwater (mean residence time >300 y). The B (δB = 22.9 ± 3.5‰) and Sr (Sr/Sr = 0.70923 ± 0.00024) isotope ratios were not consistent with the expected isotope fingerprints of CCRs, but rather mimic the compositions of local lithologies. The isotope signatures combined with mean groundwater residence times of more than 300 years for groundwater with high Mo concentrations support a geogenic source of Mo to the groundwater, rather than CCR-induced contamination. This study demonstrates the utility of a multi-isotope approach to distinguish between fossil fuel-related and natural sources of groundwater contamination.
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http://dx.doi.org/10.1021/acs.est.7b03716DOI Listing
November 2017

A standardized and automated method of perineuronal net analysis using agglutinin staining intensity.

IBRO Rep 2016 Dec;1:54-60

Department of Integrative Physiology and Neuroscience, Washington State University, Vancouver, WA, 98686.

Perineuronal nets (PNNs) are aggregations of extracellular matrix molecules that are critical for plasticity. Their altered development or changes during adulthood appear to contribute to a wide range of diseases/disorders of the brain. An increasing number of studies examining the contribution of PNN to various behaviors and types of plasticity have analyzed the fluorescence intensity of agglutinin (WFA) as an indirect measure of the maturity of PNNs, with brighter WFA staining corresponding to a more mature PNN and dim WFA staining corresponding to an immature PNN. However, a clearly-defined and unified method for assessing the intensity of PNNs is critical to allow us to make comparisons across studies and to advance our understanding of how PNN plasticity contributes to normal brain function and brain disease states. Here we examined methods of PNN intensity quantification and demonstrate that creating a region of interest around each PNN and subtracting appropriate background is a viable method for PNN intensity quantification that can be automated. This method produces less variability and bias across experiments compared to other published analyses, and this method increases reproducibility and reliability of PNN intensity measures, which is critical for comparisons across studies in this emerging field.
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http://dx.doi.org/10.1016/j.ibror.2016.10.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5507617PMC
December 2016

Detection of Dientamoeba fragilis in animal faeces using species specific real time PCR assay.

Vet Parasitol 2016 Aug 20;227:42-7. Epub 2016 Jul 20.

Department of Microbiology, SydPath, St. Vincent's Hospital, Victoria St, Darlinghurst, N.S.W, Australia; School of Life Sciences, University of Technology, Sydney, Ultimo, N.S.W, Australia. Electronic address:

Dientamoeba fragilis is a potentially pathogenic, enteric, protozoan parasite with a worldwide distribution. While clinical case reports and prevalence studies appear regularly in the scientific literature, little attention has been paid to this parasite's biology, life cycle, host range, and possible transmission routes. Overall, these aspects of Dientamoeba biology remain poorly understood at best. In this study, a total of 420 animal samples, collected from Australia, were surveyed for the presence of Dientamoeba fragilis using PCR. Several PCR assays were evaluated for sensitivity and specificity. Two previously published PCR methods demonstrated cross reactivity with other trichomonads commonly found in animal samples. Only one assay exhibited excellent specificity. Using this assay D. fragilis was detected from one dog and one cat sample. This is the first report of D. fragilis from these animals and highlights the role companion animals may play in D. fragilis transmission. This study demonstrated that some published D. fragilis molecular assays cross react with other closely related trichomonads and consequently are not suitable for animal prevalence studies.
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http://dx.doi.org/10.1016/j.vetpar.2016.07.025DOI Listing
August 2016

Evidence for Coal Ash Ponds Leaking in the Southeastern United States.

Environ Sci Technol 2016 06 10;50(12):6583-92. Epub 2016 Jun 10.

Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States.

Coal combustion residuals (CCRs), the largest industrial waste in the United States, are mainly stored in surface impoundments and landfills. Here, we examine the geochemistry of seeps and surface water from seven sites and shallow groundwater from 15 sites in five states (Tennessee, Kentucky, Georgia, Virginia, and North Carolina) to evaluate possible leaking from coal ash ponds. The assessment for groundwater impacts at the 14 sites in North Carolina was based on state-archived monitoring well data. Boron and strontium exceeded background values of 100 and 150 μg/L, respectively, at all sites, and the high concentrations were associated with low δ(11)B (-9‰ to +8‰) and radiogenic (87)Sr/(86)Sr (0.7070 to 0.7120) isotopic fingerprints that are characteristic of coal ash at all but one site. Concentrations of CCR contaminants, including SO4, Ca, Mn, Fe, Se, As, Mo, and V above background levels, were also identified at all sites, but contamination levels above drinking water and ecological standards were observed in 10 out of 24 samples of impacted surface water. Out of 165 monitoring wells, 65 were impacted with high B levels and 49 had high CCR-contaminant levels. Distinct isotope fingerprints, combined with elevated levels of CCR tracers, provide strong evidence for the leaking of coal ash ponds to adjacent surface water and shallow groundwater. Given the large number of coal ash impoundments throughout the United States, the systematic evidence for leaking of coal ash ponds shown in this study highlights potential environmental risks from unlined coal ash ponds.
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http://dx.doi.org/10.1021/acs.est.6b01727DOI Listing
June 2016

Angiostrongylus cantonensis: a review of its distribution, molecular biology and clinical significance as a human pathogen.

Parasitology 2016 08 26;143(9):1087-118. Epub 2016 May 26.

Department of Microbiology,SydPath, St. Vincent's Hospital,Victoria St.,Darlinghurst,NSW,Australia.

Angiostrongylus cantonensis is a metastrongyloid nematode found widely in the Asia-Pacific region, and the aetiological agent of angiostrongyliasis; a disease characterized by eosinophilic meningitis. Rattus rats are definitive hosts of A. cantonensis, while intermediate hosts include terrestrial and aquatic molluscs. Humans are dead-end hosts that usually become infected upon ingestion of infected molluscs. A presumptive diagnosis is often made based on clinical features, a history of mollusc consumption, eosinophilic pleocytosis in cerebral spinal fluid, and advanced imaging such as computed tomography. Serological tests are available for angiostrongyliasis, though many tests are still under development. While there is no treatment consensus, therapy often includes a combination of anthelmintics and corticosteroids. Angiostrongyliasis is relatively rare, but is often associated with morbidity and sometimes mortality. Recent reports suggest the parasites' range is increasing, leading to fatalities in regions previously considered Angiostrongylus-free, and sometimes, delayed diagnosis in newly invaded regions. Increased awareness of angiostrongyliasis would facilitate rapid diagnosis and improved clinical outcomes. This paper summarizes knowledge on the parasites' life cycle, clinical aspects and epidemiology. The molecular biology of Angiostrongylus spp. is also discussed. Attention is paid to the significance of angiostrongyliasis in Australia, given the recent severe cases reported from the Sydney region.
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http://dx.doi.org/10.1017/S0031182016000652DOI Listing
August 2016

Brine Spills Associated with Unconventional Oil Development in North Dakota.

Environ Sci Technol 2016 05 27;50(10):5389-97. Epub 2016 Apr 27.

Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States.

The rapid rise of unconventional oil production during the past decade in the Bakken region of North Dakota raises concerns related to water contamination associated with the accidental release of oil and gas wastewater to the environment. Here, we characterize the major and trace element chemistry and isotopic ratios ((87)Sr/(86)Sr, δ(18)O, δ(2)H) of surface waters (n = 29) in areas impacted by oil and gas wastewater spills in the Bakken region of North Dakota. We establish geochemical and isotopic tracers that can identify Bakken brine spills in the environment. In addition to elevated concentrations of dissolved salts (Na, Cl, Br), spill waters also consisted of elevated concentrations of other contaminants (Se, V, Pb, NH4) compared to background waters, and soil and sediment in spill sites had elevated total radium activities ((228)Ra + (226)Ra) relative to background, indicating accumulation of Ra in impacted soil and sediment. We observed that inorganic contamination associated with brine spills in North Dakota is remarkably persistent, with elevated levels of contaminants observed in spills sites up to 4 years following the spill events.
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http://dx.doi.org/10.1021/acs.est.5b06349DOI Listing
May 2016

Genetic Polymorphisms Affect Mouse and Human Trace Amine-Associated Receptor 1 Function.

PLoS One 2016 31;11(3):e0152581. Epub 2016 Mar 31.

Veterans Affairs Portland Health Care System, Portland, Oregon, United States of America.

Methamphetamine (MA) and neurotransmitter precursors and metabolites such as tyramine, octopamine, and β-phenethylamine stimulate the G protein-coupled trace amine-associated receptor 1 (TAAR1). TAAR1 has been implicated in human conditions including obesity, schizophrenia, depression, fibromyalgia, migraine, and addiction. Additionally TAAR1 is expressed on lymphocytes and astrocytes involved in inflammation and response to infection. In brain, TAAR1 stimulation reduces synaptic dopamine availability and alters glutamatergic function. TAAR1 is also expressed at low levels in heart, and may regulate cardiovascular tone. Taar1 knockout mice orally self-administer more MA than wild type and are insensitive to its aversive effects. DBA/2J (D2) mice express a non-synonymous single nucleotide polymorphism (SNP) in Taar1 that does not respond to MA, and D2 mice are predisposed to high MA intake, compared to C57BL/6 (B6) mice. Here we demonstrate that endogenous agonists stimulate the recombinant B6 mouse TAAR1, but do not activate the D2 mouse receptor. Progeny of the B6XD2 (BxD) family of recombinant inbred (RI) strains have been used to characterize the genetic etiology of diseases, but contrary to expectations, BXDs derived 30-40 years ago express only the functional B6 Taar1 allele whereas some more recently derived BXD RI strains express the D2 allele. Data indicate that the D2 mutation arose subsequent to derivation of the original RIs. Finally, we demonstrate that SNPs in human TAAR1 alter its function, resulting in expressed, but functional, sub-functional and non-functional receptors. Our findings are important for identifying a predisposition to human diseases, as well as for developing personalized treatment options.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0152581PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4816557PMC
August 2016

Spontaneous Subclavian Vein Thrombosis in a Healthy Adolescent Cheerleader: A Case of Paget-Schroetter Syndrome.

Pediatr Emerg Care 2017 Oct;33(10):e92-e94

From the *Division of General Pediatrics, The Children's Hospital of Philadelphia, Philadelphia; †Department of Pediatrics, Grand View Hospital, Sellersville; ‡Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania; and §Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA.

We present the case of a healthy 13-year-old female adolescent who developed acute progressive swelling and pain in her right upper extremity that was secondary to an acute deep venous thrombosis of her right subclavian vein. Dynamic imaging revealed subclavian vein compression at the junction of the first rib and proximal third of the clavicle consistent with Paget-Schroetter syndrome, also known as effort-related thrombosis. The compressive etiology of her thrombus was most likely related to her cheerleading activity, in which she served as the pyramid base. The patient received multimodal therapy including anticoagulation, mechanical and site-directed thrombolysis, and a first rib resection. This case illustrates that frontline providers should have a high index of suspicion for an upper extremity thrombosis in pediatric patients who present with unilateral arm swelling.
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http://dx.doi.org/10.1097/PEC.0000000000000646DOI Listing
October 2017

Descriptive epidemiology of infectious gastrointestinal illnesses in Sydney, Australia, 2007-2010.

Western Pac Surveill Response J 2015 Oct-Dec;6(4):7-16. Epub 2015 Oct 6.

The iThree Institute and School of Medical and Molecular Biosciences, University of Technology, Sydney, New South Wales, Australia .

Objective: There is a lack of information about the prevalence of gastrointestinal illnesses in Australia. Current disease surveillance systems capture only a few pathogens. The aim of this study is to describe the epidemiology of infectious gastrointestinal illnesses in Sydney, Australia.

Methods: A retrospective cross-sectional study of patients with gastrointestinal symptoms who visited tertiary public hospitals in Sydney was conducted between 2007 and 2010. Patients with diarrhoea or loose stools with an enteric pathogen detected were identified. Demographic, clinical and potential risk factor data were collected from their medical records. Measures of association, descriptive and inferential statistics were analysed.

Results: In total, 1722 patients were included in this study. Campylobacter (22.0%) and Clostridium difficile (19.2%) were the most frequently detected pathogens. Stratified analysis showed that rotavirus (22.4%), norovirus (20.7%) and adenovirus (18.1%) mainly affected children under 5 years; older children (5-12 years) were frequently infected with Campylobacter spp. (29.8%) and non-typhoid Salmonella spp. (24.4%); infections with C. difficile increased with age.Campylobacter and non-typhoid Salmonella spp. showed increased incidence in summer months (December to February), while rotavirus infections peaked in the cooler months (June to November).

Discussion: This study revealed that gastrointestinal illness remains a major public health issue in Sydney. Improvement of current disease surveillance and prevention and control measures are required. This study emphasizes the importance of laboratory diagnosis of enteric infections and the need for better clinical data collection to improve management of disease risk factors in the community.
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http://dx.doi.org/10.5365/WPSAR.2015.6.2.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4712528PMC
October 2016

Alcaligenes faecalis Cellulitis After a Dog Bite: Case Report and Literature Review.

Pediatr Emerg Care 2017 Jul;33(7):497-498

From the Division of General Pediatrics, The Children's Hospital of Philadelphia; and the Department of Pediatrics, Grand View Hospital, Sellersville, Philadelphia, PA.

Alcaligenes faecalis is a gram-negative organism that is commonly found in the environment and may also be a part of normal fecal flora in humans. Although various infections with this bacteria have been described in the pediatric population, it has not been previously identified in infections as the pathogen after a dog bite. A case of a 19-month-old boy is presented with a cellulitis secondary to a dog bite, which failed oral antibiotic therapy, and progressed to worsening fever and swelling. The patient ultimately required hospitalization, intravenous antibiotics, and incision and drainage. The wound culture grew A. faecalis, whose identity was confirmed through recombinant DNA sequence analysis. Although it has been identified in cat bite wounds, A. faecalis has not been cited in the literature before in an infection after a dog bite.
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http://dx.doi.org/10.1097/PEC.0000000000000645DOI Listing
July 2017

Extended exposure to environmental cues, but not to sucrose, reduces sucrose cue reactivity in rats.

Learn Behav 2016 Mar;44(1):59-66

Western Washington University, Bellingham, WA, USA.

In the present study, we examined the effects of extinction of sucrose-predictive contextual cues and/or sucrose satiation on the expression of sucrose cue reactivity in a rat model of relapse. Context extinction was imposed by housing rats in their home cage or in the operant conditioning chamber for 17 h prior to testing. For sucrose satiation, rats were allowed unlimited access to water or sucrose for 17 h prior to testing. Cue reactivity was assessed after either one (Day 1) or 30 (Day 30) days of forced abstinence from sucrose self-administration. An abstinence-dependent increase in sucrose cue reactivity was observed in all conditions ("incubation of craving"). Context extinction dramatically reduced lever responding on both Day 1 and Day 30. Sucrose satiation had no significant effect on cue reactivity in any condition. These results demonstrate that the context in which self-administration occurs maintains a powerful influence over cue reactivity, even after extended forced abstinence. In contrast, the primary reinforcer has little control over cue reactivity. These findings highlight the important role of conditioned contextual cues in driving relapse behavior.
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http://dx.doi.org/10.3758/s13420-015-0190-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4713387PMC
March 2016

The Prevalence of Angiostrongylus cantonensis/mackerrasae Complex in Molluscs from the Sydney Region.

PLoS One 2015 22;10(5):e0128128. Epub 2015 May 22.

Department of Microbiology, SydPath, St. Vincent's Hospital, Victoria St, Darlinghurst, NSW, Australia.

Angiostrongylus cantonensis and Angiostrongylus mackerrasae are metastrongyloid nematodes that infect various rat species. Terrestrial and aquatic molluscs are intermediate hosts of these worms while humans and dogs are accidental hosts. Angiostrongylus cantonensis is the major cause of angiostrongyliasis, a disease characterised by eosinophilic meningitis. Although both A. cantonensis and A. mackerrasae are found in Australia, A. cantonensis appears to account for most infections in humans and animals. Due to the occurrence of several severe clinical cases in Sydney and Brisbane, the need for epidemiological studies on angiostrongyliasis in this region has become apparent. In the present study, a conventional PCR and a TaqMan assay were compared for their ability to amplify Angiostrongylus DNA from DNA extracted from molluscs. The TaqMan assay was more sensitive, capable of detecting the DNA equivalent to one hundredth of a nematode larva. Therefore, the TaqMan assay was used to screen molluscs (n=500) of 14 species collected from the Sydney region. Angiostrongylus DNA was detected in 2 of the 14 mollusc species; Cornu aspersum [14/312 (4.5%)], and Bradybaenia similaris [1/10 (10%)], which are non-native terrestrial snails commonly found in urban habitats. The prevalence of Angiostrongylus spp. was 3.0% ± 0.8% (CI 95%). Additionally, experimentally infected Austropeplea lessoni snails shed A. cantonensis larvae in their mucus, implicating mucus as a source of infection. This is the first Australian study to survey molluscs using real-time PCR and confirms that the garden snail, C. aspersum, is a common intermediate host for Angiostrongylus spp. in Sydney.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0128128PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4441457PMC
April 2016

In Vitro Antimicrobial Susceptibility Patterns of Blastocystis.

Antimicrob Agents Chemother 2015 Aug 18;59(8):4417-23. Epub 2015 May 18.

Department of Microbiology, St. Vincent's Hospital, Darlinghurst, NSW, Australia.

Blastocystis is the most common human enteric protist with controversial clinical significance. Metronidazole is considered a first-line treatment for Blastocystis infection; however, there has been increasing evidence for the lack of efficacy of this treatment. Treatment failure has been reported in several clinical cases, and recent in vitro studies have suggested the occurrence of metronidazole-resistant strains. In this study, we tested 12 Blastocystis isolates from 4 common Blastocystis subtypes (ST1, ST3, ST4, and ST8) against 12 commonly used antimicrobials (metronidazole, paromomycin, ornidazole, albendazole, ivermectin, trimethoprim-sulfamethoxazole [TMP-SMX], furazolidone, nitazoxanide, secnidazole, fluconazole, nystatin, and itraconazole) at 10 different concentrations in vitro. It was found that each subtype showed little sensitivity to the commonly used metronidazole, paromomycin, and triple therapy (furazolidone, nitazoxanide, and secnidazole). This study highlights the efficacy of other potential drug treatments, including trimethoprim-sulfamethoxazole and ivermectin, and suggests that current treatment regimens be revised.
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http://dx.doi.org/10.1128/AAC.04832-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4505275PMC
August 2015

Non-susceptibility to ceftaroline in healthcare-associated multiresistant MRSA in Eastern Australia.

J Antimicrob Chemother 2015 Aug 14;70(8):2413-4. Epub 2015 May 14.

Department of HIV, Immunology and Infectious Diseases, St Vincent's Hospital, Darlinghurst, Sydney, Australia Sydney Clinical School, Faculty of Medicine, University of Sydney, Sydney, Australia

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http://dx.doi.org/10.1093/jac/dkv124DOI Listing
August 2015