124 results on '"WA Thompson"'
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2. The Analysis of the Spacing of Animals, with an Example Based on Oystercatchers During the Tidal Cycle
- Author
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J. D. Goss-Custard, WA Thompson, Alasdair I. Houston, Anthony L. Moody, and B De Bruijn
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Haematopus ostralegus ,biology ,Ecology ,Food item ,Geometry ,Radius ,Residual ,biology.organism_classification ,Avoidance behaviour ,Tidal cycle ,Spatial ecology ,Common spatial pattern ,Animal Science and Zoology ,Ecology, Evolution, Behavior and Systematics ,Mathematics - Abstract
1. Methods of analysing the spatial patterns of birds are reviewed. Few methods have sought to explain an observed spatial pattern in terms of the behavioural responses between conspecifics. The spacing of oystercatchers, Haematopus ostralegus L., feeding on a mussel bed is investigated using a model of one possible response. 2. The model assumes that each individual avoids all other individuals within a certain distance, the hard-core radius, and has no interaction with other individuals beyond this distance. 3. The positions of the oystercatchers are obtained from a set of photographs. Each photograph is transformed to a plan view, and the resulting set of plan views is assembled to give the spatial pattern of birds on the mussel bed. The observed spatial pattern is summarized by means of the distribution of nearest-neighbour distances. 4. The behaviour of the birds is modelled by placing non-overlapping particles of a given radius within the region of the mussel bed occupied by the birds. The distribution of nearest-neighbour distances for the particles is obtained by simulation. The best-fitting particle radius is that which minimizes the residual error between the observed and simulated distributions of nearest-neighbour distances. 5. Statistical analyses show that avoidance behaviour, as measured by the best-fitting particle radius, decreases during the low-water period. We interpret this result in terms of the changing value of a food item to an individual through time.
- Published
- 1997
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3. The Use of a Time and Energy Budget Model of a Parent Bird to Investigate Limits to Fledging Mass in the Thick-Billed Murre
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Alasdair I Houston, WA Thompson, and AJ Gaston
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Fishery ,Thick-billed murre ,Energy expenditure ,Ecology ,Fledge ,Foraging ,Maximum size ,Nest site ,Biology ,Energy budget ,Constraint (mathematics) ,Ecology, Evolution, Behavior and Systematics - Abstract
1. We develop a general model to show how the energy delivered by a parent bird to its young may be limited by either time constraints or energy constraints acting on the parent. The model gives explicit equations for each constraint. 2. We illustrate the model using data from the Thick-billed Murre, which raises a single chick. The chick leaves the nest site at less than one third of the adult mass and unable to fly. Although this behaviour has been discussed in terms of adaptations to foraging constraints that operate on the breeding adults, these constraints have hitherto not been examined in detail. 3. We show that the maximum size of chick depends strongly on the distance that a parent must travel on a foraging trip. When the round-trip distance is more than 100 km, the Thick-billed Murre is unlikely to be able to raise the chick's fledging mass above 65% of the adult mass, and hence is unable to adopt a semi-praecocial chick-rearing strategy. 4. Our results suggest that if the parent bird is limited by energy expenditure then the time spent brooding does not have much of an effect on maximum chick size.
- Published
- 1996
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4. Least-squares estimation of diet composition from n-alkanes in herbage and faeces using matrix mathematics
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WA Thompson, RW Mayes, JA Newman, and PD Penning
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N alkanes ,business.industry ,Monogastric ,Diet composition ,Biology ,Least squares ,Biotechnology ,Fodder ,Systems research ,Simultaneous equations ,Statistics ,General Agricultural and Biological Sciences ,business ,Feces - Abstract
It is possible to estimate diet composition from an analysis of n-alkanes in the faeces of ruminant animals. For instance, to estimate the proportion of two species in a diet, two equations are constructed using the known concentrations of two different n-alkanes in the herbage and in the animal's faeces. These two equations are solved for the two unknown quantities of the diet components. Two problems exist with this method. First, it is often the case that we have estimated concentrations of more than two different n-alkanes. This can lead to a problem in deciding which two n-alkanes to use to construct the simultaneous equations. The choice of this pair of n-alkanes is arbitrary in its selection and wasteful of other useful information. The second problem is that sometimes the solution to the simultaneous equations yields nonsensical answers, such as a negative proportion of one species in the diet. In addition to making it difficult to estimate dietary proportions, estimating digestibility becomes impossible. In this paper, we present a technique which provides an estimate of the dietary proportions. This estimate uses information on all the n-alkanes available, and it has a very desirable property of being a least squares estimate. We also present a method for determining the least squares estimate subject to the constraint that all proportions must be non-negative. We provide examples for estimating the proportions of grass and clover in the diet of sheep and the digestibility of those diets.
- Published
- 1995
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5. Photosynthetic Response to Light and Nutrients in Sun-Tolerant and Shade-Tolerant Rainforest Trees. I. Growth, Leaf Anatomy and Nutrient Content
- Author
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PE Kriedemann, IE Craig, and WA Thompson
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Forest floor ,Ecophysiology ,Argyrodendron ,biology ,Flindersia brayleyana ,Plant Science ,Anatomy ,Argyrodendron trifoliolatum ,biology.organism_classification ,Agronomy and Crop Science ,Shade tolerance ,Flindersia ,Toona - Abstract
Seedling trees of Argyrodendron sp., A. trifoliolaturn, Flindersia brayleyana and Toona australis were grown for c. 180 days under one of three light regimes with either of two nutrient levels (6 treatments in all). Light regimes spanned the range of environmental conditions which these species would normally experience in northern Queensland rainforest: deep shade (1.3 mol quanta m-2 day-1, equivalent to forest floor), moderate light (5.6 mol quanta m-2 day-1, comparable to midcanopy), and strong light (23 mol quanta m-2 day-1, matching daily irradiance of exposed crowns). Long-term shade tolerance in Argyrodendron sp. and A. trifoliolaturn was associated with limited responses in growth and leaf anatomy to low light and nutrients. Starch accumulation in leaves under all treatments, and especially low nutrients, implied that supply of photoassimilate exceeded demand. Such a conservative carbon economy, plus the accumulation of stem P reserves, even in a weak light environment, is consistent with a protracted existence as part of a forest floor community. By contrast, shade-intolerant Toona is an early successional species and lacks such adaptive features. Instead, light and nutrients had a strong interactive effect on growth. Flindersia, with a broad tolerance to sun and shade, was intermediate in growth response and leaf adjustment, which is consistent with its success across a wide size range of forest gaps.
- Published
- 1992
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6. Photosynthetic Response to Light and Nutrients in Sun-Tolerant and Shade-Tolerant Rainforest Trees. II. Leaf Gas Exchange and Component Processes of Photosynthesis
- Author
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WA Thompson, LK Huang, and PE Kriedemann
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Specific leaf area ,Flindersia brayleyana ,Plant Science ,Argyrodendron trifoliolatum ,Biology ,Photosynthesis ,biology.organism_classification ,Horticulture ,Compensation point ,Botany ,Agronomy and Crop Science ,Chlorophyll fluorescence ,Shade tolerance ,Toona - Abstract
Species with contrasting shade tolerance were grown under three light by two nutrient treatments. Gas exchange by intact leaves, leaf disk O2 evolution and chlorophyll fluorescence were measured. In shade-tolerant evergreen species (Argyrodendron sp., A. trifoliolatum and Flindersia brayleyana) photosynthetic activity of seedlings in air at light saturation (A) was lower under weak (30 pmol quanta m-2 day-1 ), compared with medium (130) or strong light (535). In Toona australis, a shade-intolerant and deciduous tree, A was reduced 44% from strong to weak light treatment on high nutrients (71 mg N L-1 nutrient solution). Nevertheless, nitrogen-use efficiency for leaf photosynthesis was highest in Toona under all growing conditions and, with higher specific leaf area, probably contributes towards fast occupancy of sites which underlies early succession in this species. All species made photosynthetic and respiratory adjustments from strong to medium to weak light, which resulted in a lower light compensation point (Q0). Such adjustments were accentuated by low nutrient supply (1.0 mg N L-1 nutrient solution) and were especially pronounced for shade-intolerant Toona. Reduced Q0 in Toona was accompanied by lower A and light saturation point (QA). Both species of Argyrodendron showed no decrease in QA despite reduction in Q0 under weak light.Contrary to expectation, photosynthetic responses to light × nutrient treatments did not correlate with degree of shade tolerance accorded each species by rainforest ecologists.
- Published
- 1992
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7. Growth and Photosynthetic Response to Light and Nutrients of Flindersia brayleyana F. Muell., A Rainforest Tree With Broad Tolerance to Sun and Shade
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GC Stocker, WA Thompson, and PE Kriedemann
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Photoinhibition ,biology ,Flindersia brayleyana ,Plant Science ,Photosynthesis ,biology.organism_classification ,Photosynthetic capacity ,Flindersia ,Horticulture ,chemistry.chemical_compound ,Compensation point ,chemistry ,Chlorophyll ,Botany ,Acacia aulacocarpa ,Agronomy and Crop Science - Abstract
Seed from four species of rainforest trees with widely contrasting sunlight requirements for growth and development were sown within disturbance gaps amidst mature forest on the Herberton Range in North Queensland. Observations on seedling persistence plus comparative growth of young trees of Acacia aulacocarpa, Toona australis, Flindersia brayleyana and Darlingia darlingiana (species ranked according to adaptation from full sun to deep shade) confirmed a broad tolerance of Flindersia to sunlight under all conditions, from wide to narrow gaps (minimum 0.6% full sun equivalent). Photosynthetic attributes which underlie such broad tolerance were subsequently inferred from single leaf gas exchange, plus foliar analyses of nitrogen, phosphorus and chlorophyll on tree seedlings held for 180 days under two nutrient × three irradiance levels adjusted to represent natural irradiance incident upon the forest floor (low), mid-canopy (medium) and emergent crowns (high irradiance treatment). Medium irradiance plus high nutrients proved optimal for leaf expansion, chlorophyll content and photosynthesis in air. Growth under low irradiance was characterised by thinner leaf palisade tissue, lower rates of dark respiration, increased leaf chlorophyll per unit nitrogen and lower light compensation point for photosynthesis. Such leaves retained a relatively high photosynthetic capacity despite these other shade-leaf attributes. High irradiance plus low nutrients proved supraoptimal for leaf expansion and expression of photosynthetic activity. Chronic photoinhibition appeared to prevail because apparent quantum yield was reduced, while photosynthetic processes on a nitrogen basis were substantially impaired. Nitrogen use efficiency, as inferred from leaf chlorophyll content, light saturated CO2 assimilation rate, electron transport rate and carboxylation rate on a nitrogen basis declined with increasing growth irradiance. Some ecological implications for the establishment and growth of these rainforest tree species in disturbance gaps are discussed.
- Published
- 1988
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8. Zygotic Exposure to Venlafaxine Disrupts the Circadian Locomotor Activity Behaviour in Zebrafish Larvae.
- Author
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Thompson WA and Vijayan MM
- Subjects
- Animals, Zebrafish Proteins metabolism, Zebrafish Proteins genetics, Zygote drug effects, Zygote metabolism, Motor Activity drug effects, Melatonin pharmacology, Zebrafish embryology, Venlafaxine Hydrochloride pharmacology, Venlafaxine Hydrochloride toxicity, Larva drug effects, Locomotion drug effects, Circadian Rhythm drug effects
- Abstract
The antidepressant venlafaxine, a selective serotonin and norepinephrine reuptake inhibitor, is commonly prescribed to treat major depressive disorder and is found at high concentrations in the aquatic environment. Concerns have been raised related to the health of aquatic organisms in response to this nontargeted pharmaceutical exposure. For instance, we previously demonstrated that exposure to venlafaxine perturbs neurodevelopment, leading to behavioural alterations in zebrafish (Danio rerio). We also observed disruption in serotonin expression in the pineal and raphe, regions critical in regulating circadian rhythms, leading us to hypothesize that zygotic exposure to venlafaxine disrupts the circadian locomotor rhythm in larval zebrafish. To test this, we microinjected zebrafish embryos with venlafaxine (1 or 10 ng) and recorded the locomotor activity in 5-day-old larvae over a 24-h period. Venlafaxine deposition reduced larval locomotor activity during the light phase, but not during the dark phase of the diurnal cycle. The melatonin levels were higher in the dark compared to during the light photoperiod and this was not affected by embryonic venlafaxine deposition. Venlafaxine exposure also did not affect the transcript abundance of clock genes, including clock1a, bmal2, cry1a and per2, which showed a clear day/night rhythmicity. A notable finding was that exposure to luzindole, a melatonin receptor antagonist, decreased the locomotor activity in the control group in light, whereas the activity was higher in larvae raised from the venlafaxine-deposited embryos. Overall, zygotic exposure to venlafaxine disrupts the locomotor activity of larval zebrafish fish during the day, demonstrating the capacity of antidepressants to disrupt the circadian rhythms in behaviour. Our results suggest that disruption in melatonin signalling may be playing a role in the venlafaxine impact on circadian behaviour, but further investigation is required to elucidate the possible mechanisms in larval zebrafish., (© 2024 The Author(s). Journal of Pineal Research published by John Wiley & Sons Ltd.)
- Published
- 2024
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9. Exposure to Total Suspended Solids (TSS) Impacts Gill Structure and Function in Adult Zebrafish.
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Montoya XC, Thompson WA, Smith CM, Wilson JM, and Vijayan MM
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- Animals, Sodium-Potassium-Exchanging ATPase metabolism, Zebrafish physiology, Gills drug effects, Water Pollutants, Chemical toxicity
- Abstract
Total suspended solids (TSS) are a major contributor of anthropogenic impacts to aquatic systems. TSS exposure have been shown to affect the function of gills, but the mode of action is unclear. Zebrafish (Danio rerio) is emerging as an excellent model for mechanistic toxicology, and as there are no baseline studies on TSS effects in zebrafish gills, we tested the hypothesis that environmental concentrations of TSS damages gill structure and function in this species. Adult zebrafish were exposed to either 0, 10, 100, 500, 1000, or 2000 mg/L TSS for 4 days to assess the gill morphology. The minimal concentration that affected the gill structure was further tested for the distribution of key ion transporters, including Na
+ /K+ - ATPase (NKA) and vacuolar-type H+ -ATPase (VHA), using confocal microscopy. Our results reveal that TSS concentration as low as 100 mg/L alters the morphology of gills, including greater filament thickness, lamellae thickness, and epithelial lifting. This was also associated with a reduction in NKA immunoreactive (IR) cell count and intensity in the 100 mg/L TSS group, while there was neither a change in the VHA-IR cell count or expression nor the transcript abundance of atp6v1a and atp1a1a4 in the gills. Markers of stress response in these animals, including levels of cortisol, glucose, lactate, and glycogen were not altered after 4 days of TSS exposure. Overall, environmentally relevant concentrations of TSS can damage the gill structure and function in zebrafish and has the potential to enhance the toxicity of contaminants acting via the gills., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)- Published
- 2024
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10. Excess feeding increases adipogenesis but lowers leptin transcript abundance in zebrafish larvae.
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Thompson WA, Rajeswari JJ, Holloway AC, and Vijayan MM
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- Animals, Leptin genetics, Leptin metabolism, Larva genetics, PPAR gamma genetics, PPAR gamma metabolism, Lipids, Adipogenesis genetics, Zebrafish metabolism
- Abstract
Although fish exposed to municipal wastewater effluents (MWWE) show higher lipid accumulation, whether this is due to adipogenesis is unclear. The objective here was to identify molecular markers of adipogenesis in zebrafish (Danio rerio) larvae for use as high throughput screening tools for environmental contaminants, including obesogens in MWWE. Zebrafish larvae were fed a commercial diet at a maintenance level (5 % body mass) or in excess (25 or 50 % body mass) from day 6 to 30 days post-fertilization (dpf) to stimulate adipogenesis. We monitored fat accumulation and markers of lipid metabolism, including peroxisome proliferator-activated receptor γ (ppar γ), fatty acid synthase (fas), ELOVL fatty acid elongase 2 (elovl2), diacylglycerol O-acyltransferase 2 (dgat2), leptin (lepa and lepb), leptin receptor (lepr), and lipoprotein lipase (lpl). Excess feeding led to a higher growth rate, protein content and an increase in igf1 transcript abundance. Also, these larvae had higher triglyceride levels and accumulated lipids droplets in the abdominal cavity and viscera. The molecular markers of adipogenesis, including fas, elovl2, and dgat2, were upregulated, while the transcript abundance of lpl, a lipolytic gene, was transiently lower due to excess feeding. The increased adiposity seen at 30 dpf due to excess feeding coincided with a lower lep but not lepr transcript abundance in zebrafish. Our results demonstrate that excess feeding alters the developmental programming of key genes involved in lipid homeostasis, leading to excess lipid accumulation in zebrafish larvae. Overall, fas, elovl2, lpl, and dgat2, but not lep or ppar γ, have the potential to be biomarkers of adipogenesis in zebrafish larvae., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)
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- 2024
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11. Effect of elevated embryonic incubation temperature on the temperature preference of juvenile lake ( Coregonus clupeaformis ) and round whitefish ( Prosopium cylindraceum ).
- Author
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Harman A, Mahoney H, Thompson WA, Fuzzen MLM, Aggarwal B, Laframboise L, Boreham DR, Manzon RG, Somers CM, and Wilson JY
- Abstract
Anthropogenic impacts can lead to increased temperatures in freshwater environments through thermal effluent and climate change. Thermal preference of aquatic organisms can be modulated by abiotic and biotic factors including environmental temperature. Whether increased temperature during embryogenesis can lead to long-term alterations in thermal preference has not been explicitly tested in native freshwater species. Lake ( Coregonus clupeaformis ) and round ( Prosopium cylindraceum ) whitefish were incubated at natural and elevated temperatures until hatching, following which, all groups were moved to common garden conditions (15°C) during the post-hatching stage. Temperature preference was determined at 8 months (Lake whitefish only) and 12 months of age (both species) using a shuttle box system. Round whitefish preferred a cooler temperature when incubated at 2 and 6°C compared with 0.5°C. Lake whitefish had similar temperature preferences regardless of age, weight and incubation temperature. These results reveal that temperature preference in freshwater fish can be programmed during early development, and that round whitefish may be more sensitive to incubation temperature. This study highlights the effects that small increases in temperature caused by anthropogenic impacts may have on cold-adapted freshwater fish., Competing Interests: D.R.B. received funding from Bruce Power and held a position of Bruce Power Chair in Radiation and Health at the Northern Ontario School of Medicine., (© The Author(s) 2023. Published by Oxford University Press and the Society for Experimental Biology.)
- Published
- 2023
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12. Highly selective CO 2 photoreduction to CO on MOF-derived TiO 2 .
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Garvin M, Thompson WA, Tan JZY, Kampouri S, Ireland CP, Smit B, Brookfield A, Collison D, Negahdar L, Beale AM, Maroto-Valer MM, McIntosh RD, and Garcia S
- Abstract
Metal-Organic Framework (MOF)-derived TiO
2 , synthesised through the calcination of MIL-125-NH2 , is investigated for its potential as a CO2 photoreduction catalyst. The effect of the reaction parameters: irradiance, temperature and partial pressure of water was investigated. Using a two-level design of experiments, we were able to evaluate the influence of each parameter and their potential interactions on the reaction products, specifically the production of CO and CH4 . It was found that, for the explored range, the only statistically significant parameter is temperature, with an increase in temperature being correlated to enhanced production of both CO and CH4 . Over the range of experimental settings explored, the MOF-derived TiO2 displays high selectivity towards CO (98%), with only a small amount of CH4 (2%) being produced. This is notable when compared to other state-of-the-art TiO2 based CO2 photoreduction catalysts, which often showcase lower selectivity. The MOF-derived TiO2 was found to have a peak production rate of 8.9 × 10-4 μmol cm-2 h-1 (2.6 μmol g-1 h-1 ) and 2.6 × 10-5 μmol cm-2 h-1 (0.10 μmol g-1 h-1 ) for CO and CH4 , respectively. A comparison is made to commercial TiO2 , P25 (Degussa), which was shown to have a similar activity towards CO production, 3.4 × 10-3 μmol cm-2 h-1 (5.9 μmol g-1 h-1 ), but a lower selectivity preference for CO (3 : 1 CH4 : CO) than the MOF-derived TiO2 material developed here. This paper showcases the potential for MIL-125-NH2 derived TiO2 to be further developed as a highly selective CO2 photoreduction catalyst for CO production., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2023
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13. Rationed and satiated growth hormone transgenic Coho Salmon (Oncorhynchus kisutch) show tissue specific differences in energy stores.
- Author
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Thompson WA, Lau GY, Richards JG, and Devlin RH
- Abstract
Growth hormone transgenic coho salmon experience increased growth rates, driven primarily through elevated feed intake and feed conversion. However, neuropeptides that signal appetite stimulation have been shown to exhibit variable responses across fed states, suggesting a more complex system mediating growth in these fish. Studies have proposed that growth hormone may have a modulatory role on the energy reserves of fish, possibly through AMP-activated protein kinase (AMPK) activation. AMPK, an energy sensor in cells, has previously been shown to be upregulated in growth hormone transgenic salmon when compared to wild type, however, whether this effect is seen across fed states is unknown. Here, we tested the hypothesis that growth hormone induces an energetic deficit in metabolic tissues, leading to constitutive AMPK activation in growth hormone transgenic salmon. This study compared AMPK activity, ATP, and glycogen, of the liver, heart, and muscle of wild-type, and growth hormone transgenic salmon either fed to satiation or a wild-type ration. The results suggest that white muscle ATP levels in growth hormone salmon are elevated in satiation and rationed conditions. In the liver, growth hormone transgenic salmon fed a rationed wild-type diet experience reductions in ATP level and glycogen. In none of the tissues examined, did AMPK activity change. Taken together, these results indicate that growth hormone transgenic salmon experience metabolic duress when not fed to satiation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)
- Published
- 2023
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14. Antidepressants as Endocrine Disrupting Compounds in Fish.
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Thompson WA and Vijayan MM
- Subjects
- Animals, Antidepressive Agents adverse effects, Endocrine System, Fishes, Endocrine Disruptors adverse effects, Water Pollutants, Chemical toxicity
- Abstract
As antidepressant usage by the global population continues to increase, their persistent detection in aquatic habitats from municipal wastewater effluent release has led to concerns of possible impacts on non-target organisms, including fish. These pharmaceuticals have been marketed as mood-altering drugs, specifically targeting the monoaminergic signaling in the brain of humans. However, the monoaminergic systems are highly conserved and involved in the modulation of a multitude of endocrine functions in vertebrates. While most studies exploring possible impact of antidepressants on fish have focused on behavioural perturbations, a smaller spotlight has been placed on the endocrine functions, especially related to reproduction, growth, and the stress response. The purpose of this review is to highlight the possible role of antidepressants as endocrine disruptors in fish. While studies linking the effects of environmentally relevant levels of antidepressant on the endocrine system in fish are sparse, the emerging evidence suggests that early-life exposure to these compounds have the potential to alter the developmental programming of the endocrine system, which could persist as long-term and multigenerational effects in teleosts., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Thompson and Vijayan.)
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- 2022
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15. Sex-Specific and Long-Term Impacts of Early-Life Venlafaxine Exposure in Zebrafish.
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Thompson WA, Shvartsburd Z, and Vijayan MM
- Abstract
Venlafaxine, a selective serotonin and norepinephrine reuptake inhibitor, is a widely prescribed antidepressant that is detected in municipal wastewater effluents at µg/L concentrations. It has been shown to impact the early life stages of fish, including neurodevelopment and behaviour in larvae, but whether such early exposures have longer-term consequences are far from clear. Here, we sought to determine whether zygotic deposition of venlafaxine, mimicking a maternal transfer scenario, disturbs the metabolic rate and behavioural performance using zebrafish ( Danio rerio ). This was tested using freshly fertilized embryos (1-4 cell stage) microinjected with either 0, 1 or 10 ng of venlafaxine and raised to either juvenile (60 days post-fertilization) or adult (10-12 months post-fertilization). Zygotic venlafaxine exposure led to a reduction in the active metabolic rate and aerobic scope, but this was only observed in female fish. On the other hand, the total distance travelled in an open field assessment was greater at the highest concentration of venlafaxine only in the adult males. At the juvenile stage, behavioural assessments demonstrated that venlafaxine exposure may increase boldness-including hyperactivity, lower thigmotaxis, and a reduction in the distance to a novel object. Taken together, these results demonstrate that zygotic venlafaxine exposure may impact developmental programming in a sex-specific manner in fish.
- Published
- 2022
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16. The antidepressant venlafaxine perturbs cardiac development and function in larval zebrafish.
- Author
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Thompson WA, Shvartsburd Z, and Vijayan MM
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- Animals, Antidepressive Agents toxicity, Embryo, Nonmammalian, Heart, Larva, Venlafaxine Hydrochloride toxicity, Water Pollutants, Chemical toxicity, Zebrafish
- Abstract
Venlafaxine, a selective serotonin and norepinephrine reuptake inhibitor, is a highly prescribed antidepressant and is detected at µg/L concentrations in waterways receiving municipal wastewater effluents. We previously showed that early-life venlafaxine exposure disrupted the normal development of the nervous system and reduces larval activity in zebrafish (Danio rerio). However, it is unclear whether the reduced swimming activity may be associated with impaired cardiac function. Here we tested the hypothesis that zygotic exposure to venlafaxine impacts the development and function of the larval zebrafish heart. Venlafaxine (0, 1 or 10 ng) was administered by microinjection into freshly fertilized zebrafish embryos (1-4 cell stage) to assess heart development and function during early-life stages. Venlafaxine deposition in the zygote led to precocious development of the embryo heart, including the timing of the first heartbeat, increased heart size, and a higher heart rate at 24- and 48-hours post-fertilization (hpf). Also, waterborne exposure to environmental levels of this antidepressant during early development increased the heart rate at 48 hpf of zebrafish larvae mimicking the zygotic deposition. The venlafaxine-induced higher heart rate in the embryos was abolished in the presence of NAN-190, an antagonist of the 5HT
1A receptor. Also, heart rate dropped below control levels in the 10 ng, but not 1 ng venlafaxine group at 72 and 96 hpf. An acute stressor reduced the venlafaxine-induced heart rate at 48 hpf but did not affect the already reduced heart rate at 72 and 96 hpf in the 10 ng venlafaxine group. Our results suggest that the higher heart rate in the venlafaxine group may be due to an enhanced serotonin stimulation of the 5HT1A receptor. Taken together, early-life venlafaxine exposure disrupts cardiac development and has the potential to compromise the cardiovascular performance of larval zebrafish., (Copyright © 2021 Elsevier B.V. All rights reserved.)- Published
- 2022
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17. Venlafaxine deposition in the zygote disrupts the endocrine control of growth in juvenile zebrafish.
- Author
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Thompson WA and Vijayan MM
- Subjects
- Animals, Larva, Venlafaxine Hydrochloride toxicity, Zygote, Water Pollutants, Chemical toxicity, Zebrafish
- Abstract
The antidepressant venlafaxine can be found at levels nearing μg/L in waterways receiving municipal wastewater effluent, exposing non-target organisms, such as fish, to this chemical. We showed previously that zygotic exposure to venlafaxine alters neurodevelopment and behaviour in zebrafish (Danio rerio) larvae. Here, we tested the hypothesis that the zygotic deposition of venlafaxine disrupts endocrine pathways related to growth in zebrafish. This was carried out by microinjecting embryos (1-4 cell stage) with either 0, 1, or 10 ng venlafaxine. Zygotic venlafaxine deposition reduced the growth of fish after 30 days post-fertilization. Specific growth rate was particularly impacted by 1 ng venlafaxine. This growth retardation corresponded with the disruption of endocrine pathways involved in growth and metabolism. Venlafaxine exposed embryos displayed reduced transcript abundance of key genes involved in anabolic hormone action. Early-life venlafaxine exposure also reduced whole-body insulin and glucose content in juveniles. Target-tissue glucose uptake measurements indicated that high venlafaxine deposition preferentially increased glucose uptake to the brain. Zygotic venlafaxine did not affect feed intake nor altered the transcript abundance of key feeding-related peptides. Taken together, zygotic venlafaxine deposition compromises zebrafish growth by disrupting multiple endocrine pathways, and this study has identified key markers for potential use in risk assessment., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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18. Zygotic exposure to venlafaxine disrupts cortisol stress axis activity in multiple generations of zebrafish.
- Author
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Thompson WA and Vijayan MM
- Subjects
- Animals, Female, Larva, Stress, Physiological, Venlafaxine Hydrochloride toxicity, Hydrocortisone, Zebrafish
- Abstract
Ubiquitous use of antidepressants has resulted in increased concentrations of these pharmaceuticals in waterways receiving municipal wastewater effluent. Amongst these, venlafaxine, a selective serotonin and norepinephrine reuptake inhibitor, is commonly found at concentrations surpassing 1 ppb in surface waters. We recently showed that the deposition of venlafaxine in zebrafish (Danio rerio) embryos impacts neural development in the hypothalamus, suggesting the possibility of neuroendocrine disruptions due to this antidepressant. Here, we tested the hypothesis that early developmental exposure to venlafaxine disrupts the long-term functioning of the hypothalamus-pituitary-interrenal (HPI) axis in zebrafish. Embryos (1-4 cell stage) were injected with either 0, 1, or 10 ng venlafaxine, and the ontogeny of cortisol content, as well as changes in cortisol levels following a stressor in larvae and adults were assessed across 3 generations. Zygotic venlafaxine exposure did not affect the ontogeny of cortisol production, but there was a disruption in the cortisol response to stressor exposure, which was also evident in multiple generations. In the F
0 generation, venlafaxine exposure did not affect cortisol levels in response to stressor exposure in larvae, but adult females, and not males, showed an attenuated cortisol response compared to control fish. This reduction in cortisol levels in the females was rescued by stimulation with adrenocorticotropic hormone, suggesting that the disruption was at the level of the hypothalamus-pituitary axis. Venlafaxine-mediated disruption in HPI axis functioning was also evident in the F1 and F2 generations, including impaired cortisol responses to a stressor in adult female and larval fish, respectively. Taken together, our results suggest that venlafaxine is an endocrine disruptor, and early developmental exposure to this antidepressant may have long-term and generational consequences on cortisol stress axis activity in zebrafish., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)- Published
- 2021
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19. Emerging and Historical Contaminants Detected in Desert Rodents Collected Near a Low-Level Radioactive Waste Site.
- Author
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Cleary RS, Karnjanapiboonwong A, Thompson WA, Lasee SJ, Subbiah S, Kauble RK, Andraski BJ, and Anderson TA
- Subjects
- Animals, Ecosystem, Environmental Monitoring, Rodentia, Polychlorinated Biphenyls analysis, Radioactive Waste
- Abstract
In an effort to determine contaminant presence, concentrations, and movement from a low-level radioactive waste (LLRW) burial disposal site to ecosystems in the surrounding area, a study was developed to assess concentrations of per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), and tritium. To complete this assessment small mammals, vegetation, soil, and insect samples were collected from areas within and adjacent to the Beatty, Nevada, LLRW site and from a reference area located approximately 3 km south of the LLRW site. Samples underwent analysis via liquid chromatography tandem mass spectrometry, gas chromatography mass spectrometry, or scintillation spectroscopy depending on the analyte of interest. Small mammal tissues showed maximum concentrations of over 1700 ng/g for PFAS, 1600 ng/g for PCBs, and 10 000 Bq/kg for tritium. The primary contaminants found in soil samples were PCBs, with maximum concentrations exceeding 25 ng/g. Trace amounts of PFAS were also detected in soils and insects. Only qualitative data were obtained from vegetation samples because of the complex matrix of the dominant plant species (creosote bush; Larrea tridentata [Sessé & Moc. ex DC.] Coville). Overall, these data indicate the presence of various anthropogenic contaminants in the ecosystem surrounding the LLRW area, but additional analyses are necessary to confirm the sources and migration pathways of PFAS and PCBs in this hyperarid environment. Environ Toxicol Chem 2021;40:727-734. © 2020 SETAC., (© 2020 SETAC.)
- Published
- 2021
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20. Zygotic Venlafaxine Exposure Impacts Behavioral Programming by Disrupting Brain Serotonin in Zebrafish.
- Author
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Thompson WA and Vijayan MM
- Subjects
- Animals, Brain, Serotonin, Venlafaxine Hydrochloride toxicity, Water Pollutants, Chemical toxicity, Zebrafish
- Abstract
The antidepressant venlafaxine, a selective serotonin and norepinephrine reuptake inhibitor, is present in surface waters downstream of wastewater treatment plants. We previously showed that zygotic venlafaxine deposition alters larval behavior in zebrafish ( Danio rerio ), but the mechanisms were unknown. Here we tested the hypothesis that venlafaxine disrupts central serotonergic development, leading to impaired behavioral responses in zebrafish larvae. This was tested by microinjecting embryos with venlafaxine immediately after fertilization and performing spatial distribution of serotonin immunoreactivity, as well as characterizing target genes involved in serotonin turnover in the zebrafish brain. We provide evidence that venlafaxine exposure reduces serotonin immunoreactivity and tyrosine hydroxylase-positive cell populations in specific larval brain regions, and this corresponded with reduced larval activity observed in the drug-exposed group. Lowered serotonin was not due to either reduced synthesis or increased breakdown capacity. However, co-injection of serotonin alongside venlafaxine in embryos recovered brain serotonin immunoreactivity, tyrosine hydroxylase-positive cell populations, and rescued venlafaxine-mediated behavioral changes. Overall, our results demonstrate for the first time that early life exposure to venlafaxine perturbs brain development, which may be due to reduced serotonin, leading to altered larval behavior in zebrafish.
- Published
- 2020
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21. Environmental levels of venlafaxine impact larval behavioural performance in fathead minnows.
- Author
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Thompson WA and Vijayan MM
- Subjects
- Alberta, Animals, Larva drug effects, Wastewater, Antidepressive Agents toxicity, Cyprinidae physiology, Venlafaxine Hydrochloride toxicity, Water Pollutants, Chemical toxicity
- Abstract
Venlafaxine, a selective serotonin and norepinephrine reuptake inhibitor, is one of the most abundant antidepressants in municipal wastewater effluents (MWWE). The early life stages are particularly sensitive to contaminant exposure, but few studies have examined whether persistent exposure to venlafaxine impart adverse developmental outcomes. The fathead minnow (Pimephales promelas) is a widely used model for ecotoxicological studies, and this fish is native to Alberta, Canada. We tested the hypothesis that environmental levels of venlafaxine compromises early developmental behavioural performances in fathead minnows. Embryos were exposed to waterborne venlafaxine at either 0, 0.06, 0.33, 0.66, 1.37 or 3 μg L
-1 concentration for 7 days. Environmental levels of venlafaxine did not impact the survival, hatch rate or heart rate of fathead minnow embryos and larvae but reduced the growth of larvae even at concentrations as low as 0.06 μg L-1 . We validated thigmotaxis as a screen for anxiolytic and anxiogenic behaviour in fathead minnow larvae by exposing them to concentrations of ethanol and caffeine, respectively. Behavioural analyses revealed that early developmental exposure to venlafaxine does not alter thigmotaxis but reduced the activity of fathead minnows. The larval behavioural assays reported here for fathead minnow have the potential to be used as screening tools for the risk assessment of neurotoxic contaminants in MWWE. Overall, we demonstrate for the first time that exposure to environmental levels of venlafaxine during the critical early developmental window does not elicit an anxiogenic response but may adversely affect the larval growth performance of fathead minnows., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest associated with this study., (Copyright © 2020 Elsevier Ltd. All rights reserved.)- Published
- 2020
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22. Synthesis of TiO 2- x /W 18 O 49 hollow double-shell and core-shell microspheres for CO 2 photoreduction under visible light.
- Author
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Tan JZY, Gavrielides S, Belekoukia M, Thompson WA, Negahdar L, Xia F, Maroto-Valer MM, and Beale AM
- Abstract
TiO2-x/W18O49 with core-shell or double-shelled hollow microspheres were synthesized through a facile multi-step solvothermal method. The formation of the hollow microspheres with a double-shell was a result of the Kirkendall effect during the solvothermal treatment with concentrated NaOH. The advanced architecture significantly enhanced the electronic properties of TiO2-x/W18O49, improving by more than 30 times the CO2 photoreduction efficiency compared to the pristine W18O49. Operando DRIFTS measurements revealed that the yellow TiO2-x was a preferable CO2 adsorption and conversion site.
- Published
- 2020
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23. Alkali modified P25 with enhanced CO 2 adsorption for CO 2 photoreduction.
- Author
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Tan JZY, Gavrielides S, Xu HR, Thompson WA, and Maroto-Valer MM
- Abstract
To improve the CO
2 adsorption on the photocatalyst, which is an essential step for CO2 photoreduction, solid solutions were fabricated using a facile calcination treatment at 900 °C. Using various alkalis, namely NaOH, Na2 CO3 , KOH, K2 CO3 , the resulted samples presented a much higher CO2 adsorption capacity, which was measured with the pulse injection of CO2 on the temperature programmed desorption workstation, compared to the pristine Evonik P25. As a result, all of the fabricated solid solutions produced higer yield of CO under UV light irradiation due to the increased basicity of the solid solutions even though they possessed only the rutile polymorph of TiO2 . The highest CO2 adsorption capacity under UV irradiation was observed in the sample treated with NaOH, which contained the highest amount of isolated hydroxyls, as shown in the FTIR studies., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2020
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24. Plant Uptake of Per- and Polyfluoroalkyl Acids under a Maximum Bioavailability Scenario.
- Author
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Lasee S, Subbiah S, Thompson WA, Karnjanapiboonwong A, Jordan J, Payton P, and Anderson TA
- Subjects
- Biodegradation, Environmental, Biological Availability, Humans, Plant Roots metabolism, Plant Shoots metabolism, Soil, Fluorocarbons metabolism, Plants metabolism
- Abstract
Although many studies have evaluated the fate of per- and polyfluoroalkyl acids (PFAAs) in aquatic environments, few have observed their fate in terrestrial environments. It has been proposed that ingestion could be a major PFAA exposure route for humans. We determined PFAA uptake in radish, carrot, and alfalfa under a maximum bioavailability scenario. Bioconcentration factors (BCFs) were determined in the edible tissue of radish (perfluorobutanesulfonate [PFBS] = 72; perfluorohexanesulfonate [PFHxS] = 13; perfluoroheptanoate [PFHpA] = 65; perfluorooctanoate [PFOA] = 18; perfluorooctanesulfonate [PFOS] = 2.9; and perfluorononanoate [PFNA] = 9.6), carrot (PFBS = 5.9; PFHxS = 1.1; PFHpA = 29; PFOA = 3.1; PFOS = 1; and PFNA = 1.4), and alfalfa (PFBS = 107; PFHxS = 12; PFHpA = 91; PFOA = 10; PFOS = 1.4; and PFNA = 1.7). Some of these PFAA BCFs are as much as 2 orders of magnitude higher than those measured previously in plants grown in biosolid-amended soils. Environ Toxicol Chem 2019;38:2497-2502. © 2019 SETAC., (© 2019 SETAC.)
- Published
- 2019
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25. Systematic study of TiO 2 /ZnO mixed metal oxides for CO 2 photoreduction.
- Author
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Thompson WA, Olivo A, Zanardo D, Cruciani G, Menegazzo F, Signoretto M, and Maroto-Valer MM
- Abstract
A two component three degree simplex lattice experimental design was employed to evaluate the impact of different mixing fractions of TiO
2 and ZnO on an ordered mesoporous SBA-15 support for CO2 photoreduction. It was anticipated that the combined advantages of TiO2 and ZnO: low cost, non-toxicity and combined electronic properties would facilitate CO2 photoreduction. The fraction of ZnO had a statistically dominant impact on maximum CO2 adsorption ( β2 = 22.65, p -value = 1.39 × 10-4 ). The fraction of TiO2 used had a statistically significant positive impact on CO ( β1 = 9.71, p -value = 2.93 × 10-4 ) and CH4 ( β1 = 1.43, p -value = 1.35 × 10-3 ) cumulative production. A negative impact, from the interaction term between the fractions of TiO2 and ZnO, was found for CH4 cumulative production ( β3 = -2.64, p -value = 2.30 × 10-2 ). The systematic study provided evidence for the possible loss in CO2 photoreduction activity from sulphate groups introduced during the synthesis of ZnO. The decrease in activity is attributed to the presence of sulphate species in the ZnO prepared, which may possibly act as charge carrier and/or radical intermediate scavengers., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2019
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26. Do naked mole rats accumulate a metabolic acidosis or an oxygen debt in severe hypoxia?
- Author
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Pamenter ME, Dzal YA, Thompson WA, and Milsom WK
- Subjects
- Acidosis physiopathology, Anaerobiosis, Animals, Female, Male, Mole Rats physiology, Oxygen metabolism, Oxygen Consumption physiology
- Abstract
In severe hypoxia, most vertebrates increase anaerobic energy production, which results in the development of a metabolic acidosis and an O
2 debt that must be repaid during reoxygenation. Naked mole rats (NMRs) are among the most hypoxia-tolerant mammals, capable of drastically reducing their metabolic rate in acute hypoxia while staying active and alert. We hypothesized that a key component of remaining active is an increased reliance on anaerobic metabolism during severe hypoxia. To test this hypothesis, we exposed NMRs to progressive reductions in inspired O2 (9-3% O2 ) followed by reoxygenation (21% O2 ) and measured breathing frequency, heart rate, behavioural activity, body temperature, metabolic rate, and also metabolic substrates and pH in blood and tissues. We found that NMRs exhibit robust metabolic rate depression in acute hypoxia, accompanied by declines in all physiological and behavioural variables examined. However, blood and tissue pH were unchanged, and tissue concentrations of ATP and phosphocreatine were maintained. NMRs increased their reliance on carbohydrates in hypoxia, and glucose was mobilized from the liver to the blood. Upon reoxygenation, NMRs entered into a coma-like state for ∼15-20 min, during which metabolic rate was negligible and body temperature remained suppressed. However, an imbalance in the time taken for the rates of O2 uptake ( V̇O ) and CO2 2 production ( V̇CO ) to return to normoxic levels during reoxygenation hint at the possibility that NMRs do utilize anaerobic metabolism during hypoxia but have a tissue and/or blood buffering capacity that masks typical markers of metabolic acidosis, and that the synthesis of glucose from lactate, rather than lactate oxidation, is prioritized during recovery., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2019. Published by The Company of Biologists Ltd.)2 - Published
- 2019
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27. OsmiR528 Enhances Cold Stress Tolerance by Repressing Expression of Stress Response-related Transcription Factor Genes in Plant Cells.
- Author
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Tang W and Thompson WA
- Abstract
Background: MicroRNAs participate in many molecular mechanisms and signaling trans-duction pathways that are associated with plant stress tolerance by repressing expression of their target genes. However, how microRNAs enhance tolerance to low temperature stress in plant cells remains elusive., Objective: In this investigation, we demonstrated that overexpression of the rice microRNA528 (Os-miR528) increases cell viability, growth rate, antioxidants content, ascorbate peroxidase (APOX) activi-ty, and superoxide dismutase (SOD) activity and decreases ion leakage rate and thiobarbituric acid reac-tive substances (TBARS) under low temperature stress in Arabidopsis (Arabidopsis thaliana), pine (Pi-nus elliottii), and rice (Oryza sativa)., Methods: To investigate the potential mechanism of OsmiR528 in increasing cold stress tolerance, we examined expression of stress-associated MYB transcription factors OsGAMYB-like1, OsMYBS3, OsMYB4, OsMYB3R-2, OsMYB5, OsMYB59, OsMYB30, OsMYB1R, and OsMYB20 in rice cells by qRT-PCR., Results: Our experiments demonstrated that OsmiR528 decreases expression of transcription factor OsMYB30 by targeting a F-box domain containing protein gene (Os06g06050), which is a positive regulator of OsMYB30. In OsmiR528 transgenic rice, reduced OsMYB30 expression results in in-creased expression of BMY genes OsBMY2, OsBMY6, and OsBMY10. The transcript levels of the OsBMY2, OsBMY6, and OsBMY10 were elevated by OsMYB30 knockdown, but decreased by Os-MYB30 overexpression in OsmiR528 transgenic cell lines, suggesting that OsmiR528 increases low temperature tolerance by modulating expression of stress response-related transcription factor., Conclusion: Our experiments provide novel information in increasing our understanding in molecular mechanisms of microRNAs-associated low temperature tolerance and are valuable in plant molecular breeding from monocotyledonous, dicotyledonous, and gymnosperm plants.
- Published
- 2019
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28. Venlafaxine in Embryos Stimulates Neurogenesis and Disrupts Larval Behavior in Zebrafish.
- Author
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Thompson WA, Arnold VI, and Vijayan MM
- Subjects
- Animals, Behavior, Animal, Embryo, Nonmammalian, Larva, Neurogenesis, Venlafaxine Hydrochloride toxicity, Water Pollutants, Chemical toxicity, Zebrafish
- Abstract
Venlafaxine, a widely prescribed antidepressant, is a selective serotonin and norepinephrine reuptake inhibitor in humans, and this drug is prevalent in municipal wastewater effluents. While studies have shown that this drug affects juvenile fish behavior, little is known about the developmental impact on nontarget aquatic animals. We tested the hypothesis that venlafaxine deposition in the egg, mimicking maternal transfer of this antidepressant, disrupts developmental programming using zebrafish (Danio rerio) as a model. Embryos (1-4 cell stage) were microinjected with either 1 or 10 ng venlafaxine, which led to a rapid reduction (90%) of this drug in the embryo at hatch. There was a concomitant increase in the concentration of the major metabolite o-desmethylvenlafaxine during the same period. Embryonic exposure to venlafaxine accelerated early development, increased hatching rate and produced larger larvae at 5 days post fertilization. Also, there was an increase in neuronal birth in the hypothalamus, dorsal thalamus, posterior tuberculum, and the preoptic region, and this corresponded with a higher spatial expression of nrd4, a key marker of neurogenesis. The venlafaxine-exposed larvae were less active and covered shorter distance in a light and dark behavioral test compared to the controls. Overall, zygotic exposure to venlafaxine disrupts early development, including brain function, and compromises larval behavior, suggesting impact of this drug on developmental programming in zebrafish.
- Published
- 2017
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29. Microplastics in a freshwater environment receiving treated wastewater effluent.
- Author
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Lasee S, Mauricio J, Thompson WA, Karnjanapiboonwong A, Kasumba J, Subbiah S, Morse AN, and Anderson TA
- Subjects
- Lakes, Waste Disposal, Fluid, Wastewater chemistry, Wastewater statistics & numerical data, Environmental Monitoring, Plastics analysis, Water Pollutants, Chemical analysis
- Abstract
Small plastic fragments (microplastics or solid particles <5 mm in size or "microbeads" used in personal care products and cosmetics) may ultimately find their way into aquatic environments. We studied the presence of microplastics (particle sizes 53-105 μm and 106-179 μm) spatially and temporally in 3 connected urban lakes being fed by treated wastewater effluent in Lubbock, Texas. These lakes also serve as drainage during storm events. Water samples from drainage playa wetlands within the city were also collected. Our interest was in determining the presence or absence of microplastics in a freshwater environment as well as the source apportionment between personal care products (via wastewater) and discarded plastics (via runoff). Results showed that average concentrations of microplastics in samples collected from lakes ranged from 0.79 ± 0.88 mg/L to 1.56 ± 1.64 mg/L for the 53-105 μm size fraction and from 0.31 ± 0.72 mg/L to 1.25 ± 1.98 mg/L for the 106-179 μm size fraction. For samples collected from playa wetlands, average microplastic concentrations ranged from 0.64 ± 0.92 mg/L to 5.51 ± 9.09 mg/L for the 53-105 μm size fraction and from nondetectable (ND) to 1.79 ± 3.04 mg/L for the 106-179 μm size fraction. Our results (based on comparison of microplastic masses) suggest that urban runoff also contributes microplastics to surface water in addition to the treated wastewater effluent (in this particular case). The present findings may assist in adopting additional monitoring efforts and provide information on the potential contribution of secondary microplastic input into aquatic environments. Integr Environ Assess Manag 2017;13:528-532. © 2017 SETAC., (© 2017 SETAC.)
- Published
- 2017
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30. Experiences of Pain and Expectations for Its Treatment Among Former Buruli Ulcer Patients.
- Author
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Woolley RJ, Velink A, Phillips RO, Thompson WA, Abass KM, van der Werf TS, de Zeeuw J, and Stienstra Y
- Subjects
- Acetaminophen pharmacology, Adolescent, Adult, Aged, Amoxicillin pharmacology, Anti-Bacterial Agents pharmacology, Anti-Inflammatory Agents pharmacology, Buruli Ulcer microbiology, Case-Control Studies, Cloxacillin pharmacology, Female, Ghana, Humans, Hydrogen Peroxide pharmacology, Male, Middle Aged, Mycobacterium ulcerans drug effects, Mycobacterium ulcerans isolation & purification, Neglected Diseases drug therapy, Neglected Diseases microbiology, Vitamins pharmacology, World Health Organization, Young Adult, Buruli Ulcer drug therapy, Pain drug therapy
- Abstract
Buruli ulcer (BU) is one of the 17 neglected tropical diseases for which the World Health Organization has adopted resolutions to improve treatment. BU was previously described as a relatively painless condition; however, recent research has indicated that some patients experience substantial pain. The objective of this study was to explore patients' experiences of pain and their expectations for its treatment. Semistructured interviews were conducted in a BU-endemic region of Ghana. Interviews were held with former BU patients (N = 20) and community controls (N = 19). Former patients were asked about BU-related pain and their expectations for its treatment. The interviews were conducted in October 2014, and were audiotaped, translated and transcribed into English, and then qualitatively analyzed. Of the 20 former BU patients interviewed, 19 (95%) reported experiencing pain, with patients reporting pain as a consequence of the ulcer and wound management. Some participants expressed pain through crying, whereas others did not openly express pain, sometimes because they feared the repercussions of doing so. Patients wanted to receive pain relief; however, many were unable to name a medication. Nonpharmaceutical options were cited as being an alternative. Many BU patients experience pain; however, former patients and community members alike appear to have a limited knowledge about available pain relief. A low-cost alternative to medication may be the use of nonpharmaceutical means for pain relief. Routine pain assessment may reduce patients' fear and unwillingness to express pain. Awareness of such issues will be valuable when implementing a BU pain relief guideline., (© The American Society of Tropical Medicine and Hygiene.)
- Published
- 2016
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31. TARGIT-R (Retrospective): North American Experience with Intraoperative Radiation Using Low-Kilovoltage X-Rays for Breast Cancer.
- Author
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Valente SA, Tendulkar RD, Cherian S, O'Rourke C, Greif JM, Bailey L, Uhl V, Bethke KP, Donnelly ED, Rudolph R, Pederson A, Summer T, Lottich SC, Ross DL, Laronga C, Loftus L, Abbott AM, Kelemen P, Hermanto U, Friedman NB, Bedi GC, Joh JE, Thompson WA 3rd, Hoefer RA, Wilson JP, Kang SK, Rosen B, Ruffer J, Bravo L, Police A, Escallon JM, Fyles AW, McCready DR, Graves GM, Rohatgi N, Eaker JA, Graves J, Willey SC, Tousimis EA, Collins BT, Shaw CM, Riley L, Deb N, Kelly T, Andolino DL, Boisvert ME, Lyons J, Small W Jr, and Grobmyer SR
- Subjects
- Adult, Aged, Aged, 80 and over, Breast Neoplasms pathology, Canada, Carcinoma, Ductal, Breast secondary, Disease-Free Survival, Female, Humans, Intraoperative Care, Lymphatic Metastasis, Mastectomy, Segmental adverse effects, Middle Aged, Neoplasm Staging, Neoplasm, Residual, Radiotherapy methods, Radiotherapy Dosage, Registries, Retrospective Studies, Sentinel Lymph Node pathology, Tumor Burden, United States, Breast Neoplasms therapy, Carcinoma, Ductal, Breast therapy, Neoplasm Recurrence, Local, Patient Selection, Radiotherapy statistics & numerical data
- Abstract
Background: Single-dose intraoperative radiotherapy (IORT) is an emerging treatment for women with early stage breast cancer. The objective of this study was to define the frequency of IORT use, patient selection, and outcomes of patients treated in North America., Methods: A multi-institutional retrospective registry was created, and 19 institutions using low-kilovoltage IORT for the treatment of breast cancer entered data on patients treated at their institution before July 31, 2013. Patient selection, IORT treatment details, complications, and recurrences were analyzed., Results: From 2007 to July 31, 2013, a total of 935 women were identified and treated with lumpectomy and IORT. A total of 822 patients had at least 6 months' follow-up documented and were included in the analysis. The number of IORT cases performed increased significantly over time (p < 0.001). The median patient age was 66.8 years. Most patients had disease that was <2 cm in size (90 %) and was estrogen positive (91 %); most patients had invasive ductal cancer (68 %). Of those who had a sentinel lymph node procedure performed, 89 % had negative sentinel lymph nodes. The types of IORT performed were primary IORT in 79 %, secondary IORT in 7 %, or planned boost in 14 %. Complications were low. At a median follow-up of 23.3 months, crude in-breast recurrence was 2.3 % for all patients treated., Conclusions: IORT use for the treatment of breast cancer is significantly increasing in North America, and physicians are selecting low-risk patients for this treatment option. Low complication and local recurrence rates support IORT as a treatment option for selected women with early stage breast cancer.
- Published
- 2016
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32. Hardness does not affect the physiological responses of wild and domestic strains of diploid and triploid rainbow trout Oncorhynchus mykiss to short-term exposure to pH 9.5.
- Author
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Thompson WA, Rodela TM, and Richards JG
- Subjects
- Ammonia blood, Animals, Animals, Domestic, Brain Chemistry, Calcium Carbonate, Chlorides blood, Hydrocortisone blood, Ploidies, Water chemistry, Water Pollutants, Chemical, Diploidy, Hydrogen-Ion Concentration, Oncorhynchus mykiss physiology, Stress, Physiological, Triploidy
- Abstract
This study examined the effects of water hardness on the physiological responses associated with high pH exposure in multiple strains of diploid and triploid rainbow trout Oncorhynchus mykiss. To accomplish this, three wild strains and one domesticated strain of diploid and triploid O. mykiss were abruptly transferred from control soft water (City of Vancouver dechlorinated tap water; pH 6·7; [CaCO3 ] < 17·9 mg l(-1) ) to control soft water (handling control), high pH soft water (pH 9·5; [CaCO3 ] < 17·9 mg l(-1) ), or high pH hard water (pH 9·5; [CaCO3 ] = 320 mg l(-1) ) followed by sampling at 24 h for physiological measurements. There was a significant effect of ploidy on loss of equilibrium (LOE) over the 24 h exposure, with only triploid O. mykiss losing equilibrium at high pH in both soft and hard water. Furthermore, exposure to pH 9·5 resulted in significant decreases in plasma sodium and chloride, and increases in plasma and brain ammonia with no differences between soft and hard water. There was no significant effect of strain on LOE, but there were significant differences between strains in brain ammonia and plasma cortisol. Overall, there were no clear protective effects of hardness on high pH exposure in these strains of O. mykiss., (© 2016 The Fisheries Society of the British Isles.)
- Published
- 2016
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33. Identification of the major capsid protein of erythrocytic necrosis virus (ENV) and development of quantitative real-time PCR assays for quantification of ENV DNA.
- Author
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Purcell MK, Pearman-Gillman S, Thompson RL, Gregg JL, Hart LM, Winton JR, Emmenegger EJ, and Hershberger PK
- Subjects
- Animals, DNA Virus Infections diagnosis, DNA Virus Infections virology, Fish Diseases virology, Iridoviridae classification, Iridoviridae genetics, Phylogeny, Real-Time Polymerase Chain Reaction veterinary, Sequence Analysis, DNA veterinary, Capsid Proteins genetics, DNA Virus Infections veterinary, Fish Diseases diagnosis, Fishes, Iridoviridae physiology
- Abstract
Viral erythrocytic necrosis (VEN) is a disease of marine and anadromous fish that is caused by the erythrocytic necrosis virus (ENV), which was recently identified as a novel member of family Iridoviridae by next-generation sequencing. Phylogenetic analysis of the ENV DNA polymerase grouped ENV with other erythrocytic iridoviruses from snakes and lizards. In the present study, we identified the gene encoding the ENV major capsid protein (MCP) and developed a quantitative real-time PCR (qPCR) assay targeting this gene. Phylogenetic analysis of the MCP gene sequence supported the conclusion that ENV does not group with any of the currently described iridovirus genera. Because there is no information regarding genetic variation of the MCP gene across the reported host and geographic range for ENV, we also developed a second qPCR assay for a more conserved ATPase-like gene region. The MCP and ATPase qPCR assays demonstrated good analytical and diagnostic sensitivity and specificity based on samples from laboratory challenges of Pacific herring Clupea pallasii The qPCR assays had similar diagnostic sensitivity and specificity as light microscopy of stained blood smears for the presence of intraerythrocytic inclusion bodies. However, the qPCR assays may detect viral DNA early in infection prior to the formation of inclusion bodies. Both qPCR assays appear suitable for viral surveillance or as a confirmatory test for ENV in Pacific herring from the Salish Sea., (© 2016 The Author(s).)
- Published
- 2016
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34. The effects of strain and ploidy on the physiological responses of rainbow trout (Oncorhynchus mykiss) to pH 9.5 exposure.
- Author
-
Thompson WA, Rodela TM, and Richards JG
- Subjects
- Ammonia blood, Animals, Body Weight, Brain metabolism, Hydrogen-Ion Concentration, Muscles chemistry, Oncorhynchus mykiss classification, Oncorhynchus mykiss genetics, Urea blood, Oncorhynchus mykiss physiology, Ploidies
- Abstract
We characterized the physiological effects of exposure to pH9.5 on one domesticated and four wild strains of diploid and triploid juvenile rainbow trout (Oncorhynchus mykiss) over two consecutive years. In the first year, 35-70% of the individuals from the wild strains showed a loss of equilibrium (LOE) at 12 h exposure to pH9.5, with all fish from wild strains experiencing a LOE by 48 h. In contrast, <20% of the domesticated strain showed LOE over the 48 h exposure to pH9.5. In our second experiment, similar strain effects were observed, but far fewer fish showed LOE (≤50% in all strains) over 72 h at pH9.5. In both experiments, there was no effect of ploidy on time to LOE. In the fish that did not show LOE, high pH exposure resulted in significant increases in plasma, brain and muscle ammonia, with no effect of strain or ploidy on the extent of ammonia accumulation. Glutamine accumulated in the brain during high pH exposure, with a stoichiometric decrease in glutamate, but no differences were noted among strains or ploidies. Lactate also accumulated in the plasma to a similar extent in all trout strains and ploidies. Plasma chloride decreased at 24h exposure in all trout strains and ploidies, but recovered by 72 h. No change was observed in plasma sodium. Overall, our data suggest that the domesticated strain of trout is more tolerant of pH9.5 than the wild strains, but these differences in tolerance cannot be explained by our sub-lethal assessment of ammonia balance or ion regulation., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2015
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35. Assessing the validity and reproducibility of genome-scale predictions.
- Author
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Sugden LA, Tackett MR, Savva YA, Thompson WA, and Lawrence CE
- Subjects
- Adenosine Deaminase, Animals, Drosophila genetics, Genome, RNA Editing, Reproducibility of Results, Software, Genomics methods, Models, Statistical
- Abstract
Motivation: Validation and reproducibility of results is a central and pressing issue in genomics. Several recent embarrassing incidents involving the irreproducibility of high-profile studies have illustrated the importance of this issue and the need for rigorous methods for the assessment of reproducibility., Results: Here, we describe an existing statistical model that is very well suited to this problem. We explain its utility for assessing the reproducibility of validation experiments, and apply it to a genome-scale study of adenosine deaminase acting on RNA (ADAR)-mediated RNA editing in Drosophila. We also introduce a statistical method for planning validation experiments that will obtain the tightest reproducibility confidence limits, which, for a fixed total number of experiments, returns the optimal number of replicates for the study., Availability: Downloadable software and a web service for both the analysis of data from a reproducibility study and for the optimal design of these studies is provided at http://ccmbweb.ccv.brown.edu/reproducibility.html .
- Published
- 2013
- Full Text
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36. Paradoxical responses after start of antimicrobial treatment in Mycobacterium ulcerans infection.
- Author
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Nienhuis WA, Stienstra Y, Abass KM, Tuah W, Thompson WA, Awuah PC, Awuah-Boateng NY, Adjei O, Bretzel G, Schouten JP, and van der Werf TS
- Subjects
- Adolescent, Buruli Ulcer microbiology, Child, Female, HIV, Humans, Male, Prospective Studies, Skin pathology, Young Adult, Anti-Bacterial Agents administration & dosage, Buruli Ulcer drug therapy, Buruli Ulcer pathology, Mycobacterium ulcerans isolation & purification
- Abstract
Background: Antimicrobial killing in mycobacterial infections may be accompanied by (transient) clinical deterioration, known as paradoxical reaction. To search for patterns reflecting such reactions in the treatment of Buruli ulcer (Mycobacterium ulcerans infection), the evolution of lesions of patients treated with antimicrobials was prospectively assessed., Methods: The lesion size of participants of the BURULICO antimicrobial trial (with lesions ≤10 cm cross-sectional diameter) was assessed by careful palpation and recorded by serial acetate sheet tracings. Patients were treated with antimicrobials for 8 weeks. For the size analysis, participants whose treatment had failed, had skin grafting, or were coinfected with human immunodeficiency virus were excluded. For every time point, surface area was compared with the previous assessment. A generalized additive mixed model was used to study lesion evolution. Nonulcerative lesions were studied using digital images recording possible subsequent ulceration., Results: Of 151 participants, 134 were included in the lesion size analysis. Peak paradoxical response occurred at week 8; >30% of participants showed an increase in lesion size as compared with the previous (week 6) assessment. Seventy-five of 90 (83%) of nonulcerative lesions ulcerated after start of treatment. Nine participants developed new lesions during or after treatment. All lesions subsequently healed., Conclusions: After start of antimicrobial treatment for Buruli ulcer, new or progressive ulceration is common before healing sets in. This paradoxical response, most prominent at the end of the 8-week antimicrobial treatment, should not be misinterpreted as failure to respond to treatment. Clinical Trials Registration. ClinicalTrials.gov, NCT00321178.
- Published
- 2012
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37. High-throughput mapping of protein occupancy identifies functional elements without the restriction of a candidate factor approach.
- Author
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Ferraris L, Stewart AP, Gemberling MP, Reid DC, Lapadula MJ, Thompson WA, and Fairbrother WG
- Subjects
- Cell Differentiation, Cells, Cultured, DNA chemistry, Embryonic Stem Cells cytology, Embryonic Stem Cells metabolism, Pluripotent Stem Cells metabolism, Regulatory Sequences, Nucleic Acid, Repressor Proteins genetics, DNA-Binding Proteins analysis, High-Throughput Screening Assays methods, Transcription Factors analysis
- Abstract
There are a variety of in vivo and in vitro methods to determine the genome-wide specificity of a particular trans-acting factor. However there is an inherent limitation to these candidate approaches. Most biological studies focus on the regulation of particular genes, which are bound by numerous unknown trans-acting factors. Therefore, most biological inquiries would be better addressed by a method that maps all trans-acting factors that bind particular regions rather than identifying all regions bound by a particular trans-acting factor. Here, we present a high-throughput binding assay that returns thousands of unbiased measurements of complex formation on nucleic acid. We applied this method to identify transcriptional complexes that form on DNA regions upstream of genes involved in pluripotency in embryonic stem cells (ES cells) before and after differentiation. The raw binding scores, motif analysis and expression data are used to computationally reconstruct remodeling events returning the identity of the transcription factor(s) most likely to comprise the complex. The most significant remodeling event during ES cell differentiation occurred upstream of the REST gene, a transcriptional repressor that blocks neurogenesis. We also demonstrate how this method can be used to discover RNA elements and discuss applications of screening polymorphisms for allelic differences in binding.
- Published
- 2011
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- View/download PDF
38. High-throughput binding analysis determines the binding specificity of ASF/SF2 on alternatively spliced human pre-mRNAs.
- Author
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Chang B, Levin J, Thompson WA, and Fairbrother WG
- Subjects
- Binding Sites, Exons, Genome, Humans, Protein Binding, RNA-Binding Proteins, Serine-Arginine Splicing Factors, High-Throughput Screening Assays methods, Nuclear Proteins metabolism, RNA Precursors metabolism, RNA Splicing
- Abstract
High-throughput immunoprecipitation studies of transcription factors and splicing factors have revolutionized the fields of transcription and splicing. Recent location studies on Nova1/2 and Fox2 have identified a set of cellular targets of these splicing factors. One problem with identifying binding sites for splicing factors arises from the transient role of RNA in gene expression. The primary role of most splicing factors is to bind pre-mRNA co-transcriptionally and participate in the extremely rapid process of splice site selection and catalysis. Pre-mRNA is a labile species with a steady state level that is three orders of magnitude less abundant than mRNA. As many splicing factors also bind mRNA to some degree, these substrates tend to dominate the output of location studies. Here we present an in-vitro method for screening RNA protein interactions that circumvents these problems. We screen approximately 4000 alternatively spliced exons and the entire Hepatitis C genome for binding of ASF/SF2, the only splicing factor demonstrated to function as an oncogene. From the pre-mRNA sequences returned in this screen we discovered physiologically relevant ASF recognition element motifs. ASF binds two motifs: a C-rich and a purine rich motif. Comparisons with similar data derived from the hnRNP protein PTB reveals little overlap between strong PTB and ASF/SF2 sites. We illustrate how this method could be employed to screen disease alleles with the set of small molecules that have been shown to alter splicing in search for therapies for splicing diseases.
- Published
- 2010
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- View/download PDF
39. Antimicrobial treatment for early, limited Mycobacterium ulcerans infection: a randomised controlled trial.
- Author
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Nienhuis WA, Stienstra Y, Thompson WA, Awuah PC, Abass KM, Tuah W, Awua-Boateng NY, Ampadu EO, Siegmund V, Schouten JP, Adjei O, Bretzel G, and van der Werf TS
- Subjects
- Administration, Oral, Adolescent, Adult, Buruli Ulcer diagnosis, Child, Drug Administration Schedule, Drug Therapy, Combination, Endpoint Determination, Female, Follow-Up Studies, Ghana, Humans, Injections, Intramuscular, Male, Mycobacterium ulcerans isolation & purification, Rifampin therapeutic use, Statistics, Nonparametric, Time Factors, Treatment Outcome, Young Adult, Anti-Bacterial Agents therapeutic use, Buruli Ulcer drug therapy, Clarithromycin therapeutic use, Leprostatic Agents therapeutic use, Mycobacterium ulcerans drug effects, Streptomycin therapeutic use
- Abstract
Background: Surgical debridement was the standard treatment for Mycobacterium ulcerans infection (Buruli ulcer disease) until WHO issued provisional guidelines in 2004 recommending treatment with antimicrobial drugs (streptomycin and rifampicin) in addition to surgery. These recommendations were based on observational studies and a small pilot study with microbiological endpoints. We investigated the efficacy of two regimens of antimicrobial treatment in early-stage M ulcerans infection., Methods: In this parallel, open-label, randomised trial undertaken in two sites in Ghana, patients were eligible for enrolment if they were aged 5 years or older and had early (duration <6 months), limited (cross-sectional diameter <10 cm), M ulcerans infection confirmed by dry-reagent-based PCR. Eligible patients were randomly assigned to receive intramuscular streptomycin (15 mg/kg once daily) and oral rifampicin (10 mg/kg once daily) for 8 weeks (8-week streptomycin group; n=76) or streptomycin and rifampicin for 4 weeks followed by rifampicin and clarithromycin (7.5 mg/kg once daily), both orally, for 4 weeks (4-week streptomycin plus 4-week clarithromycin group; n=75). Randomisation was done by computer-generated minimisation for study site and type of lesion (ulceration or no ulceration). The randomly assigned allocation was sent from a central site by cell-phone text message to the study coordinator. The primary endpoint was lesion healing at 1 year after the start of treatment without lesion recurrence or extensive surgical debridement. Analysis was by intention-to-treat. This trial is registered with ClinicalTrials.gov, number NCT00321178., Findings: Four patients were lost to follow-up (8-week streptomycin, one; 4-week streptomycin plus 4-week clarithromycin, three). Since these four participants had healed lesions at their last assessment, they were included in the analysis for the primary endpoint. 73 (96%) participants in the 8-week streptomycin group and 68 (91%) in the 4-week streptomycin plus 4-week clarithromycin group had healed lesions at 1 year (odds ratio 2.49, 95% CI 0.66 to infinity; p=0.16, one-sided Fisher's exact test). No participants had lesion recurrence at 1 year. Three participants had vestibulotoxic events (8-week streptomycin, one; 4-week streptomycin plus 4-week clarithromycin, two). One participant developed an injection abscess and two participants developed an abscess close to the initial lesion, which was incised and drained (all three participants were in the 4-week streptomycin plus 4-week clarithromycin group)., Interpretation: Antimycobacterial treatment for M ulcerans infection is effective in early, limited disease. 4 weeks of streptomycin and rifampicin followed by 4 weeks of rifampicin and clarithromycin has similar efficacy to 8 weeks of streptomycin and rifampicin; however, the number of injections of streptomycin can be reduced by switching to oral clarithromycin after 4 weeks., Funding: European Union (EU FP6 2003-INCO-Dev2-015476) and Buruli Ulcer Groningen Foundation., (Copyright 2010 Elsevier Ltd. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
40. Next-generation SELEX identifies sequence and structural determinants of splicing factor binding in human pre-mRNA sequence.
- Author
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Reid DC, Chang BL, Gunderson SI, Alpert L, Thompson WA, and Fairbrother WG
- Subjects
- Base Sequence, Humans, Ligands, Nucleic Acid Conformation, Polypyrimidine Tract-Binding Protein metabolism, Protein Binding, RNA Precursors chemistry, RNA Precursors genetics, RNA Precursors metabolism, Ribonucleoproteins, Small Nuclear metabolism, RNA Precursors analysis, RNA Splicing, Sequence Analysis, DNA methods
- Abstract
Many splicing factors interact with both mRNA and pre-mRNA. The identification of these interactions has been greatly improved by the development of in vivo cross-linking immunoprecipitation. However, the output carries a strong sampling bias in favor of RNPs that form on more abundant RNA species like mRNA. We have developed a novel in vitro approach for surveying binding on pre-mRNA, without cross-linking or sampling bias. Briefly, this approach entails specifically designed oligonucleotide pools that tile through a pre-mRNA sequence. The pool is then partitioned into bound and unbound fractions, which are quantified by a two-color microarray. We applied this approach to locating splicing factor binding sites in and around approximately 4000 exons. We also quantified the effect of secondary structure on binding. The method is validated by the finding that U1snRNP binds at the 5' splice site (5'ss) with a specificity that is nearly identical to the splice donor motif. In agreement with prior reports, we also show that U1snRNP appears to have some affinity for intronic G triplets that are proximal to the 5'ss. Both U1snRNP and the polypyrimidine tract binding protein (PTB) avoid exonic binding, and the PTB binding map shows increased enrichment at the polypyrimidine tract. For PTB, we confirm polypyrimidine specificity and are also able to identify structural determinants of PTB binding. We detect multiple binding motifs enriched in the PTB bound fraction of oligonucleotides. These motif combinations augment binding in vitro and are also enriched in the vicinity of exons that have been determined to be in vivo targets of PTB.
- Published
- 2009
- Full Text
- View/download PDF
41. Automated mapping of large-scale chromatin structure in ENCODE.
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Lian H, Thompson WA, Thurman R, Stamatoyannopoulos JA, Noble WS, and Lawrence CE
- Subjects
- Base Sequence, Computer Simulation, Molecular Sequence Data, Chromatin chemistry, Chromatin genetics, Chromosome Mapping methods, Models, Chemical, Models, Genetic, Sequence Analysis, DNA methods
- Abstract
Motivation: A recently developed DNaseI assay has given us our first genome-wide view of chromatin structure. In addition to cataloging DNaseI hypersensitive sites, these data allows us to more completely characterize overall features of chromatin accessibility. We employed a Bayesian hierarchical change-point model (CPM), a generalization of a hidden Markov Model (HMM), to characterize tiled microarray DNaseI sensitivity data available from the ENCODE project., Results: Our analysis shows that the accessibility of chromatin to cleavage by DNaseI is well described by a four state model of local segments with each state described by a continuous mixture of Gaussian variables. The CPM produces a better fit to the observed data than the HMM. The large posterior probability for the four-state CPM suggests that the data falls naturally into four classes of regions, which we call major and minor DNaseI hypersensitive sites (DHSs), regions of intermediate sensitivity, and insensitive regions. These classes agree well with a model of chromatin in which local disruptions (DHSs) are concentrated within larger domains of intermediate sensitivity, the accessibility islands. The CPM assigns 92% of the bases within the ENCODE regions to the insensitive regions. The 5.8% of the bases that are in regions of intermediate sensitivity are clearly enriched in functional elements, including genes and activating histone modifications, while the remaining 2.2% of the bases in hypersensitive regions are very strongly enriched in these elements., Availability: The CPM software is available upon request from the authors.
- Published
- 2008
- Full Text
- View/download PDF
42. A phylogenetic Gibbs sampler that yields centroid solutions for cis-regulatory site prediction.
- Author
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Newberg LA, Thompson WA, Conlan S, Smith TM, McCue LA, and Lawrence CE
- Subjects
- Animals, Automation, Conserved Sequence, Genome, Genome, Bacterial, Genomics, Humans, Mice, Models, Statistical, Phylogeny, Promoter Regions, Genetic, Regulatory Sequences, Nucleic Acid, Algorithms, Computational Biology methods
- Abstract
Motivation: Identification of functionally conserved regulatory elements in sequence data from closely related organisms is becoming feasible, due to the rapid growth of public sequence databases. Closely related organisms are most likely to have common regulatory motifs; however, the recent speciation of such organisms results in the high degree of correlation in their genome sequences, confounding the detection of functional elements. Additionally, alignment algorithms that use optimization techniques are limited to the detection of a single alignment that may not be representative. Comparative-genomics studies must be able to address the phylogenetic correlation in the data and efficiently explore the alignment space, in order to make specific and biologically relevant predictions., Results: We describe here a Gibbs sampler that employs a full phylogenetic model and reports an ensemble centroid solution. We describe regulatory motif detection using both simulated and real data, and demonstrate that this approach achieves improved specificity, sensitivity, and positive predictive value over non-phylogenetic algorithms, and over phylogenetic algorithms that report a maximum likelihood solution., Availability: The software is freely available at http://bayesweb.wadsworth.org/gibbs/gibbs.html., Supplementary Information: Supplementary data are available at Bioinformatics online.
- Published
- 2007
- Full Text
- View/download PDF
43. The Gibbs Centroid Sampler.
- Author
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Thompson WA, Newberg LA, Conlan S, McCue LA, and Lawrence CE
- Subjects
- Algorithms, Binding Sites, Genetic Variation, Internet, Markov Chains, Monte Carlo Method, Repetitive Sequences, Nucleic Acid, Statistics, Nonparametric, Transcription Initiation Site, User-Computer Interface, Computational Biology methods, Sequence Analysis, DNA methods, Software, Transcription Factors metabolism
- Abstract
The Gibbs Centroid Sampler is a software package designed for locating conserved elements in biopolymer sequences. The Gibbs Centroid Sampler reports a centroid alignment, i.e. an alignment that has the minimum total distance to the set of samples chosen from the a posteriori probability distribution of transcription factor binding-site alignments. In so doing, it garners information from the full ensemble of solutions, rather than only the single most probable point that is the target of many motif-finding algorithms, including its predecessor, the Gibbs Recursive Sampler. Centroid estimators have been shown to yield substantial improvements, in both sensitivity and positive predictive values, to the prediction of RNA secondary structure and motif finding. The Gibbs Centroid Sampler, along with interactive tutorials, an online user manual, and information on downloading the software, is available at: http://bayesweb.wadsworth.org/gibbs/gibbs.html.
- Published
- 2007
- Full Text
- View/download PDF
44. In vitro and in vivo characterization of p-amino-phenethyl-m-trifluoromethylphenyl piperazine (PAPP), a novel serotonergic agonist with anthelmintic activity against Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus colubriformis.
- Author
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White WH, Gutierrez JA, Naylor SA, Cook CA, Gonzalez IC, Wisehart MA, Smith CK 2nd, and Thompson WA
- Subjects
- Animals, Dose-Response Relationship, Drug, Gerbillinae, Larva drug effects, Molecular Structure, Piperazines chemistry, Anthelmintics pharmacology, Piperazines pharmacology, Trichostrongyloidea drug effects
- Abstract
The neurotransmitter serotonin (5-hydroxy tryptamine or 5HT) regulates key physiological processes in nematodes such as locomotion and feeding. PAPP (p-amino-phenethyl-m-trifluoromethylphenyl piperazine) is a known agonist of the 5-HT(1Hc) receptor of the barber pole worm, Haemonchus contortus. In this study, PAPP was highly active against L3-stage larvae of H. contortus and Trichostrongylus colubriformis in an in vitro larval migration assay, with EC50 values of 9.36 and 11.8 microM, respectively, that were comparable to levamisole (10.2 microM) and superior to pyrantel (55.39 microM). When administered orally or subcutaneously to nematode infected gerbils, PAPP provided >99% efficacy against H. contortus and >98% efficacy against Teladorsagia circumcincta at 100 mg/kg, comparable to levamisole at 10 mg/kg. Drug titration revealed significant activity down to 50 mg/kg against these two species. Spectrum was limited, however, with somewhat lower efficacy (83%) in T. colubriformis infected gerbils at 100 mg/kg. Oral delivery of hydrochloride, acetate and phosphate salts of PAPP to nematode infected gerbils did not result in an increase in either potency or spectrum. The finding that PAPP exhibits significant anthelmintic activity suggests that the nematode-specific serotonergic system is a viable target for future anthelmintic discovery.
- Published
- 2007
- Full Text
- View/download PDF
45. Cytokine responses to stimulation of whole blood from patients with Buruli ulcer disease in Ghana.
- Author
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Westenbrink BD, Stienstra Y, Huitema MG, Thompson WA, Klutse EO, Ampadu EO, Boezen HM, Limburg PC, and van der Werf TS
- Subjects
- Female, Ghana, Humans, Immunity, Cellular, Interferon-gamma blood, Interferon-gamma immunology, Interleukin-10 blood, Interleukin-10 immunology, Interleukin-4 blood, Interleukin-4 immunology, Male, Mycobacterium Infections, Nontuberculous blood, Mycobacterium ulcerans, Time Factors, Tuberculosis blood, Tuberculosis immunology, Cytokines blood, Cytokines immunology, Mycobacterium Infections, Nontuberculous immunology
- Abstract
Buruli ulcer disease (BUD), caused by Mycobacterium ulcerans, follows an indolent course of initial progression to ulceration accompanied by extensive tissue damage. It has been suggested that healing disease stages are accompanied by a protective immune response. We hypothesized that interleukin-4 (IL-4)- or IL-10-induced downregulation of Th-1 responses plays a key role in the progression of early BUD and that healing is accompanied by an augmented Th-1 response. Gamma interferon (IFN-gamma), IL-4, and IL-10 responses were measured after in vitro stimulation with phytohemagglutinin (PHA) and tuberculin purified protein derivative (PPD) of whole blood from 39 (23 early- and 16 late-stage) BUD patients and 39 healthy control subjects in Ghana. Additionally, 30 patients with active or treated tuberculosis (TB) serving as PPD-responsive positive controls were studied. Early-stage BUD patients produced significantly lower levels of IFN and IFN-gamma/IL-4 ratios compared to late-stage BUD patients after PHA stimulation. Compared to that of controls, IFN-gamma production after tuberculin stimulation was significantly higher in late-stage but not in early-stage BUD patients (P=0.009). IL-10 and IL-4 levels did not differ between BUD patients and controls, although active TB patients had significantly higher IL-10 production levels than did treated TB patients. Multivariate analysis showed no confounding factors. In conclusion, Th-1 down regulation in early BUD appears to reverse in later stages of BUD, although an association with IL-10 or IL-4 production does not emerge from our data. Here we show differences in Th-1-type cytokine production between early- and late-stage BUD that might reflect an improved immune defense over time.
- Published
- 2005
- Full Text
- View/download PDF
46. Modelling decisions of a multidisciplinary panel for admission to long-term care.
- Author
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Xie H, Chaussalet TJ, Thompson WA, and Millard PH
- Subjects
- Activities of Daily Living, Aged, Case Management, Female, Humans, Logistic Models, Long-Term Care organization & administration, Long-Term Care statistics & numerical data, Male, Needs Assessment, Nursing Homes organization & administration, Decision Support Techniques, Geriatric Assessment statistics & numerical data, Nursing Homes statistics & numerical data, Patient Admission statistics & numerical data
- Abstract
This paper describes a modelling study of a multidisciplinary review panel which is responsible for matching levels of long-term care to the needs of older people. The study aims to understand the decision making process of the review panel and to predict placement decisions based on an applicant's attributes. Data were collected from cases notes presented to the London Borough of Merton review panel. A model predicting placement of an individual to residential home, nursing home or long-stay nursing care was built using logistic regression. and correctly predicts 78% of placement decisions. The model can be used as a means of checking the consistency of the review panel's placement decisions.
- Published
- 2002
- Full Text
- View/download PDF
47. Analysis of bed usage and occupancy following the introduction of geriatric rehabilitative care in a hospital in Huesca, Spain.
- Author
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García-Navarro JA and Thompson WA
- Subjects
- Aged, Decision Support Techniques, Hospital Planning methods, Hospitals, Chronic Disease organization & administration, Hospitals, District organization & administration, Humans, Software, Spain epidemiology, Bed Occupancy statistics & numerical data, Chronic Disease rehabilitation, Hospitals, Chronic Disease statistics & numerical data, Hospitals, District statistics & numerical data, Length of Stay statistics & numerical data, Models, Theoretical
- Abstract
The decision support system BOMPS (Bed Occupancy Management and Planning Software) is used to document the effects on bed usage and occupancy of policy changes in the role of the provincial hospital of Huesca, Spain. A preliminary analysis of data for 1,834 hospital discharges during the period 1987 to 1996 showed that there was an increase in hospital activity. Estimates of bed usage and occupancy during a calendar year were calculated from aggregated weekly census data. Bed usage by short-stay patients increased following the introduction of rehabilitative care. Bed usage by long-stay patients decreased immediately following the introduction of rehabilitative care, however, the time between admission and census for long-stay patients decreased only after a number of years.
- Published
- 2001
- Full Text
- View/download PDF
48. Data requirements in a model of the natural history of Alzheimer's disease.
- Author
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Chaussalet TJ and Thompson WA
- Subjects
- Aged, Alzheimer Disease diagnosis, Alzheimer Disease mortality, Cost-Benefit Analysis, Humans, Incidence, Mass Screening economics, Sensitivity and Specificity, Alzheimer Disease physiopathology, Disease Progression, Markov Chains, Models, Theoretical
- Abstract
The "natural history" of Alzheimer's disease (AD) is discussed in terms of the data required in a general, discrete-time, non-homogeneous Markov model. The proposed model differs from similar models reported in the literature because mortality is disaggregated into AD-specific mortality and competing mortality due to other causes. Data are reviewed from the literature for AD incidence, and rates of disease progression and mortality. We conduct a preliminary sensitivity analysis using the reviewed data as base-case. The model shows that survival is sensitive to the modelling assumptions concerning mortality. This observation could have important consequences for studies that assess the cost of care following therapeutic interventions.
- Published
- 2001
- Full Text
- View/download PDF
49. Rapid direct determination of HLA-DQB1 * 0301 in the whole blood of normal individuals and cancer patients by specific polymerase chain reaction amplification.
- Author
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Lu M, Thompson WA, Lawlor DA, Reveille JD, and Lee JE
- Subjects
- Base Sequence, HLA-DQ beta-Chains, Health Status, Molecular Sequence Data, Sensitivity and Specificity, Skin Neoplasms metabolism, HLA-DQ Antigens blood, Melanoma metabolism, Nucleic Acid Amplification Techniques, Polymerase Chain Reaction methods
- Abstract
The HLA class II DQB1 * 0301 allele is present at a higher frequency in patients with malignant melanoma than in Caucasian controls. Furthermore, HLA-DQB1 * 0301 identifies a group of melanoma patients presenting with relatively advanced disease, and independently identifies a group of melanoma patients more likely to have disease recurrence. A rapid screening test for HLA-DQB1 * 0301 may be useful in clinical research involving melanoma patients. Standard molecular oligotyping for HLA class II alleles using the polymerase chain reaction (PCR)-sequence specific oligonucleotide (SSO) method is relatively expensive, labor-intensive, and involves the use of radioisotope. We therefore developed an inexpensive, rapid, non-radioactive method using sequence-specific primers, peripheral whole blood as the substrate, and strictly defined reaction conditions in a single-step PCR to allow determination of the presence or absence of genomic HLA-DQB1 * 0301. Comparison of the single-step PCR method with standard PCR-SSO oligotyping on 63 blinded samples from Caucasian melanoma patients demonstrated complete agreement between the two methods in the detection of HLA-DQB1 * 0301. Confirmatory testing in 456 additional cancer patients and healthy controls showed a sensitivity of 98.0% and a specificity of 99.4%. Single-step PCR is accurate, rapid, inexpensive, and does not require radioisotope. These advantages make it the procedure of choice for screening melanoma patients and others for the presence of the HLA-DQB1 * 0301 allele.
- Published
- 1996
- Full Text
- View/download PDF
50. Association of gastric adenocarcinoma with the HLA class II gene DQB10301.
- Author
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Lee JE, Lowy AM, Thompson WA, Lu M, Loflin PT, Skibber JM, Evans DB, Curley SA, Mansfield PF, and Reveille JD
- Subjects
- ATP Binding Cassette Transporter, Subfamily B, Member 3, ATP-Binding Cassette Transporters genetics, Adenocarcinoma genetics, Chi-Square Distribution, Colorectal Neoplasms genetics, Colorectal Neoplasms immunology, Enzyme-Linked Immunosorbent Assay, Female, Gene Frequency, HLA-DQ alpha-Chains, HLA-DQ beta-Chains, Helicobacter pylori immunology, Humans, Immunoglobulin G metabolism, Male, Middle Aged, Pancreatic Neoplasms genetics, Pancreatic Neoplasms immunology, Stomach Neoplasms genetics, Adenocarcinoma immunology, Genes, MHC Class II, HLA-DQ Antigens genetics, Stomach Neoplasms immunology
- Abstract
Background & Aims: The HLA class II gene DQB1*0301 has been linked to several cancers. This study was designed to determine if HLA-DQB1*0301 is present at altered frequency in patients with gastric, colorectal, or pancreatic adenocarcinoma., Methods: Oligotyping for HLA-DQB1*0301 was performed for 159 Caucasian patients with 160 gastrointestinal adenocarcinomas (52 gastric, 62 colorectal, and 46 pancreatic adenocarcinomas) and compared with 260 Caucasian noncancer controls. Patients with gastric adenocarcinoma underwent extended HLA class II region oligotyping. Immunoglobulin G to Helicobacter pylori was detected by enzyme-linked immunosorbent assay., Results: HLA-DQB1*0301 was more common in patients with gastric adenocarcinoma than controls (54% vs. 27%; bonferroni-corrected chi 2 P = 0.003; odds ratio, 3.2). HLA-DQB1*0301 was not associated with colorectal or pancreatic adenocarcinoma. No other HLA-DQB1 allele and no HLA-DQA1 or transporter associated with antigen processing 2 (TAP2) allele were present at altered frequency in patients with gastric adenocarcinoma. Serological evidence for H. pylori infection was less frequent in HLA-DQB1*0301-positive patients with gastric adenocarcinoma compared with HLA-DQB1*0301-negative patients (52% vs. 88%; Fisher's Exact Test; P = 0.007)., Conclusions: HLA-DQB1*0301 is more common in caucasian patients with gastric adenocarcinoma than noncancer controls. The mechanism linking HLA-DQB1*0301 with gastric adenocarcinoma is not likely through increased susceptibility to H. pylori infection.
- Published
- 1996
- Full Text
- View/download PDF
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