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A consensus protocol for the recovery of mercury methylation genes from metagenomes. Mol Ecol Resour 2022; 23:190-204. [PMID: 35839241 PMCID: PMC10087281 DOI: 10.1111/1755-0998.13687] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/24/2022] [Accepted: 07/08/2022] [Indexed: 11/27/2022]
Abstract
Mercury (Hg) methylation genes (hgcAB) mediate the formation of the toxic methylmercury and have been identified from diverse environments, including freshwater and marine ecosystems, Arctic permafrost, forest and paddy soils, coal-ash amended sediments, chlor-alkali plants discharges and geothermal springs. Here we present the first attempt at a standardized protocol for the detection, identification and quantification of hgc genes from metagenomes. Our Hg-MATE (Hg-cycling Microorganisms in Aquatic and Terrestrial Ecosystems) database, a catalogue of hgc genes, provides the most accurate information to date on the taxonomic identity and functional/metabolic attributes of microorganisms responsible for Hg methylation in the environment. Furthermore, we introduce "marky-coco", a ready-to-use bioinformatic pipeline based on de novo single-metagenome assembly, for easy and accurate characterization of hgc genes from environmental samples. We compared the recovery of hgc genes from environmental metagenomes using the marky-coco pipeline with an approach based on co-assembly of multiple metagenomes. Our data show similar efficiency in both approaches for most environments except those with high diversity (i.e., paddy soils) for which a co-assembly approach was preferred. Finally, we discuss the definition of true hgc genes and methods to normalize hgc gene counts from metagenomes.
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Impact of stereoacuity on simulated cataract surgery ability. Eye (Lond) 2021; 35:3116-3122. [PMID: 33469126 DOI: 10.1038/s41433-020-01346-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 11/21/2020] [Accepted: 11/26/2020] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND OBJECTIVES There exists a long-standing perception that diminished stereoacuity has a detrimental effect on microsurgical ability and skills acquisition. This has potential implications on the enrolment of surgical trainees into ophthalmology and other microsurgery specialities. However, strong evidence in this area is lacking. This case-control study aims to establish the exact level of stereopsis impairment at which a statistical drop in surgical performance occurs. METHODS Fifty participants were enrolled from the University of Dundee Medical School and the NHS Tayside Foundation Doctor programme. Participants were assessed for their stereopsis level before completing an orientation module on an ophthalmic surgical simulator. They were then required to repeat a task four times. Automated and objective performance levels were recorded and analysed. RESULTS Nineteen (38%) had stereopsis lower than the defined normal of 60 seconds of arc (arcsec). Statistical analysis found no correlation between visual acuity and surgical performance. No statistical difference was found between performance scores and stereoacuities of 30, 60 and 120 arcsec. A statistically significant difference was discovered in the surgical performance of participants with a stereoacuity worse than 120 arcsec (total score = -69.85) as compared to the ones with a stereoacuity of 120 arcsec or better (total score = -42.23) with p = 0.010. CONCLUSIONS This study provides evidence of a specific level of stereopsis where statistical degradation of surgical performance occurs. The findings of this work may help formulate policy on stereoacuity standards required to commence microsurgical training.
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Distribution and biogeochemical controls on net methylmercury production in Penobscot River marshes and sediment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 640-641:555-569. [PMID: 29864668 DOI: 10.1016/j.scitotenv.2018.05.276] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 05/18/2018] [Accepted: 05/22/2018] [Indexed: 05/28/2023]
Abstract
The distribution of mercury and methylmercury (MeHg) in sediment, mudflats, and marsh soils of the Hg-contaminated tidal Penobscot River was investigated, along with biogeochemical controls on production. Average total Hg in surface samples (0-3 cm) ranged from 100 to 1200 ng/g; average MeHg ranged from 5 to 50 ng/g. MeHg was usually highest at or near the surface except in highly mobile mudflats. Although total Hg concentrations in the Penobscot are elevated, it is the accumulation of MeHg that stands out in comparison to other ecosystems. Surface soils in the large Mendall Marsh, about 17 km downstream from the contamination source, contained particularly high %MeHg (averaging 8%). In Mendall marsh soil porewaters, MeHg often accounted for more than half of total Hg. Salt marshes are areas of particular concern in the Penobscot River, for they are depositional environments for a Hg-contaminated mobile pool of river sediment, hot spots for net MeHg production, and sources of risk to marsh animals. We hypothesized that exceptionally low mercury partitioning between the solid and aqueous phases (with log Kd averaging ~4.5) drives high MeHg in Penobscot marshes. The co-occurrence of iron and sulfide in filtered soil porewaters, sometimes both above 100 μM, suggests the presence of nanoparticulate and/or colloidal metal sulfides. These colloids may be stabilized by high concentrations of aromatic and potentially sulfurized dissolved organic matter (DOM) in marsh soils. Thus, Hg in Penobscot marsh soils appears to be in a highly available for microbial methylation through the formation of DOM-associated HgS complexes. Additionally, low partitioning of MeHg to marsh soils suggests high MeHg bioavailability to animals. Overall, drivers of high MeHg in Penobscot marshes include elevated Hg in soils, low partitioning of Hg to solids, high Hg bioavailability for methylation, rapidly shifting redox conditions in surface marsh soils, and high rates of microbial activity.
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Activated carbon thin-layer placement as an in situ mercury remediation tool in a Penobscot River salt marsh. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 621:839-848. [PMID: 29216592 DOI: 10.1016/j.scitotenv.2017.11.050] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 11/02/2017] [Accepted: 11/04/2017] [Indexed: 06/07/2023]
Abstract
The efficacy of thin layer in situ soil amendments was tested as a potential tool for methylmercury (MeHg) risk mitigation in Penobscot River, ME, salt marsh. Salt marshes are sites of high MeHg accumulation within the Penobscot, and key targets for remediation. The study was a fully-crossed small plot study, with four treatments (activated carbon (AC), biochar, FeCl2, and lime) and unamended controls at two sites. Plots were monitored for two years. Porewater MeHg concentrations were the main endpoint, with impacts on sediment biogeochemistry as a secondary study goal. AC-based SediMite™ was effective in reducing MeHg, and to a less extent total Hg, in surficial pore waters. AC reduced MeHg concentrations by >90% at the one month time point, and continued to significantly reduce pore water MeHg through about a year. AC was less effective in reducing total Hg in pore water, yielding about 70% reduction at one month, and 50-65% reduction at 8months. Biochar provided lower, and more variable reduction in porewater MeHg, but was not effective in reducing total Hg. Biochar amendment also increased soil MeHg. Neither FeCl2 nor lime amendments reduced pore water Hg or MeHg levels. About 50% of AC treatment applied as SediMite™ pellets was retained in marsh soils after one year. This study is one of the first field trials of in situ amendment for MeHg remediation. Our results show that thin-layer AC placement is a potential remediation tool for Hg risk to biota, especially in marshes where net MeHg accumulation is often strong.
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Abstract
Many genitourinary medicine clinics have stopped routinely performing both wet preparation microscopy and cultures to diagnose Trichomonas vaginalis (TV). Our directorate stopped microscopy when screening asymptomatic women. This audit considers whether both tests continue to be warranted for symptomatic female patients. The discrepancy between microscopy and culture results leads us to recommend that both remain necessary. Sampling standardization and improved documentation are discussed.
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Vision screening in children: a retrospective study of social and demographic factors with regards to visual outcomes. Br J Ophthalmol 2015; 100:1109-13. [PMID: 26598576 PMCID: PMC4975846 DOI: 10.1136/bjophthalmol-2015-307206] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 10/25/2015] [Indexed: 11/23/2022]
Abstract
Background Amblyopia and its risk factors have been demonstrated to be more common among children from low socioeconomic backgrounds. We sought to investigate this association in a region with orthoptic-delivered screening and whole population coverage, and to also examine the association of the Health Plan Indicator (HPI) with screening outcome. Methods Screening examination outcomes, postcodes and HPIs were extracted from the community child health database for every child who underwent preschool vision screening between March 2010 and February 2011 Tayside. We obtained the Scottish Index of Multiple Deprivation score for every child as a measure of area-based deprivation. We assessed the vulnerability/needs of the individual family through the HPI—‘Core’ (children and families receiving universal health visiting service), ‘Additional’ (receiving additional health/social support) and ‘Intensive’ (receiving high levels of support). The outcomes from follow-up examinations for those who failed screening were extracted from the orthoptic department database. Results 4365 children were screened during the year 2010–2011 of whom 523 (11.9%) failed. The odds of children from the least deprived socioeconomic group passing the visual screening test was 1.4 times higher than those from the most deprived socioeconomic group (OR 1.4, 95% CI 1.07 to 1.89, p=0.01). The odds of a child from a family assigned as ‘Intensive’ failing the preschool visual screening test was three times greater than the odds of a child from a family assigned as ‘Core’ (OR 3.59, 95% CI 1.6 to 7.8, p=0.001). Conclusions We found that children from the most deprived backgrounds and those from unstable homes were more likely to fail preschool vision screening.
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Modeling sulfate transport and distribution and methylmercury production associated with Aquifer Storage and Recovery implementation in the Everglades Protection Area. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.swaqe.2014.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Quality of life in children with primary antibody deficiency. J Clin Immunol 2014; 34:844-52. [PMID: 25005831 PMCID: PMC4165866 DOI: 10.1007/s10875-014-0072-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 06/20/2014] [Indexed: 01/25/2023]
Abstract
Primary antibody deficiency disorders (PADs) can have an excellent outlook if diagnosed early and treated appropriately, but require lifelong treatment with immunoglobulin replacement. Some carry risks of inflammatory complications even with optimal treatment. Quality of life (QoL) and the psychological impact of PADs has been relatively little studied, particularly in children. The purpose of this study was to evaluate QoL and psychological impact in a large group of children affected by a range of PADs, as well as a group with transient hypogammaglobulinemia of infancy (THI). Both parental and, where appropriate, child ratings, were collected using standardised questionnaires (PedsQL and SDQ). Higher rates of psychological difficulties, particularly emotional and peer-relationship difficulties were found in children with PAD when compared with healthy controls. Quality of life was poorer than in healthy controls, and also worse than in children affected by diabetes mellitus. Variations in QoL and the degree of psychological difficulties were found between specific diagnostic groups, with children affected by THI being amongst those with the lowest scores for QoL. Further studies are needed to corroborate and extend these findings, but this study confirms previous findings that primary antibody deficiency has a significant impact on quality of life and psychological well-being, and additionally suggests that the impact varies according to severity of the underlying condition. For those with significant difficulties psychological intervention at an early stage may be beneficial.
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Evaluation of biochars and activated carbons for in situ remediation of sediments impacted with organics, mercury, and methylmercury. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:13721-13729. [PMID: 24168448 DOI: 10.1021/es403712q] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In situ amendment of activated carbon (AC) to sediments can effectively reduce the bioavailability of hydrophobic organic contaminants. While biochars have been suggested as low-cost and sustainable alternatives to ACs, there are few comparative sorption data especially for mercury (Hg) and methylmercury (MeHg) at the low porewater concentrations in sediments. Here we compare the ability of a wide range of commercially available and laboratory synthesized ACs and biochars to sorb PAHs, PCBs, DDTs, inorganic Hg, and MeHg at environmentally relevant concentrations. Compared to natural organic matter, sorption capacity for most organic compounds was at least 1-2 orders of magnitude higher for unactivated biochars and 3-4 orders of magnitude higher for ACs which translated to sediment porewater PCB concentration reductions of 18-80% for unactivated biochars, and >99% for ACs with 5% by weight amendment to sediment. Steam activated carbons were more effective than biochars in Hg sorption and translated to modeled porewater Hg reduction in the range of 94-98% for sediments with low native Kd and 31-73% for sediments with high native Kd values for Hg. Unactivated biochars were as effective as the steam activated carbons for MeHg sorption. Predicted reductions of porewater MeHg were 73-92% for sediments with low native Kd and 57-86% for sediment with high native K(d). ACs with high surface areas therefore are likely to be effective in reducing porewater concentrations of organics, Hg, and MeHg in impacted sediments. Unactivated biochars had limited effectiveness for organics and Hg but can be considered when MeHg exposure is the primary concern.
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P72 Microscopy and culture for Trichomonas vaginalis(TV): are both tests required and should test of cures (TOC) be performed routinely?: Abstract P72 Table 1. Br J Vener Dis 2012. [DOI: 10.1136/sextrans-2012-050601c.72] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Use of two HIV-POCT tests to identify false reactives. Int J STD AIDS 2009; 20:808-9. [PMID: 19854884 DOI: 10.1258/ijsa.2009.009346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Circulating and placental endoglin concentrations in pregnancies complicated by intrauterine growth restriction and preeclampsia. Placenta 2008; 29:555-63. [PMID: 18462791 PMCID: PMC2467513 DOI: 10.1016/j.placenta.2008.03.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 03/26/2008] [Accepted: 03/29/2008] [Indexed: 12/20/2022]
Abstract
Inadequate trophoblast invasion and spiral artery remodeling leading to poor placental perfusion and hypoxia are believed to underlie preeclampsia (PE) and intrauterine growth restriction (IUGR). Recent studies implicate increased circulating endoglin as a contributor to the pathogenesis of PE. The objective of this study was to determine whether placental and circulating endoglin concentrations are altered in pregnancies complicated by intrauterine growth restricted (IUGR) infants and to address the role of hypoxia on the regulation of placental endoglin. We analyzed 10 placentas each from normal pregnant (NP), PE, and IUGR subjects. Endoglin levels were 2.5-fold higher in preeclamptic placentas compared to NP (15.4+/-2.6 versus 5.7+/-1.0, p<0.01). In contrast, endoglin levels were similar in NP and IUGR placentas (5.7+/-1.0 vs 5.9+/-1.1, p=NS). Placentas from pregnancies with both PE and IUGR exhibited endoglin levels comparable to the PE group and significantly different from normotensive pregnancies with and without IUGR pregnancies (mean 14.9+/-4.0, n=9, p=0.013). Soluble endoglin concentrations in maternal plasma were comparable in NP and IUGR, but higher in women with PE (n=10 per group, p<0.05). Despite a 2-fold increase in hypoxia inducible factor, HIF-1alpha, we did not observe endoglin upregulation in NP, PE, or IUGR placental villous explants exposed to hypoxia (2% oxygen). In contrast to PE, placental or circulating endoglin is not increased in normotensive women delivering small, asymmetrically grown (IUGR) infants at term. The placentas of women with IUGR appear to be fundamentally different from PE women with respect to endoglin, despite the proposed common pathology of deficient trophoblast invasion/spiral artery remodeling and poor placental perfusion.
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Application of ultrafiltration and stable isotopic amendments to field studies of mercury partitioning to filterable carbon in lake water and overland runoff. THE SCIENCE OF THE TOTAL ENVIRONMENT 2003; 304:295-303. [PMID: 12663191 DOI: 10.1016/s0048-9697(02)00576-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Results from pilot studies on colloidal phase transport of newly deposited mercury in lake water and overland runoff demonstrate that the combination of ultrafiltration, and stable isotope amendment techniques is a viable tool for the study of mercury partitioning to filterable carbon. Ultrafiltration mass balance calculations were generally excellent, averaging 97.3, 96.1 and 99.8% for dissolved organic carbon (DOC), total mercury (Hg(T)), and methylmercury (MeHg), respectively. Sub nanogram per liter quantities of isotope were measurable, and the observed phase distribution from replicate ultrafiltration separations on lake water agreed within 20%. We believe the data presented here are the first published colloidal phase mercury data on lake water and overland runoff from uncontaminated sites. Initial results from pilot-scale lake amendment experiments indicate that the choice of matrix used to dissolve the isotope did not affect the initial phase distribution of the added mercury in the lake. In addition there was anecdotal evidence that native MeHg was either recently produced in the system, or at a minimum, that this 'old' MeHg partitions to the same subset of DOC that binds the amended mercury. Initial results from pilot-scale overland runoff experiments indicate that less than 20% of newly deposited mercury was transported in the filterable fraction (<0.7 microm). There is some indication of colloidal phase enrichment of mercury in runoff compared to the phase distribution of organic carbon, but the mechanism of this enrichment is unclear. The phase distribution of newly deposited mercury can differ from that of organic carbon and native mercury, suggesting that the quality of the carbon (available ligands), not the quantity of carbon, regulates partitioning. Further characterization of DOC is needed to clarify the underlying mechanisms.
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Effect of pulsed dexamethasone therapy on tolerance of intravenously administered lipids in extremely low birth weight infants. J Pediatr 1999; 134:229-32. [PMID: 9931535 DOI: 10.1016/s0022-3476(99)70421-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We investigated the effect of dexamethasone on parenteral lipid tolerance in 7-day-old extremely low birth weight infants (n = 28) in a randomized, double-blind trial. Serum triglycerides were measured before and after 3 days of dexamethasone or placebo treatment. Infants treated with dexamethasone responded with higher triglyceride concentrations and greater sensitivity to incremental increases in the intravenous lipid dose.
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Abstract
BACKGROUND Post-traumatic stress disorder (PTSD) can be a persistent and disabling psychiatric disorder. There is little systematic research into the psychiatric consequences of road traffic accidents (RTAs) in children and adolescents. METHOD A consecutive sample of 8-16-year-olds attending an accident and emergency department following RTAs were screened for PTSD. Potential cases and their parent(s) were interviewed with semi-structured research instruments about six weeks and six months after the accident. RESULTS Fifty-three (45%) of the 119 subjects fell above PTSD cut-off on the Frederick's Reaction Index. Thirty-three (75%) of the 44 cases met DSM-IV criteria for PTSD. In half of these other psychiatric disorders were present, including major depressive disorder and anxiety disorders. Being female, involvement in car accidents and pre-existing depression and anxiety were associated with developing PTSD. Seventeen per cent of the sample continued to be symptomatic six months after the accident. CONCLUSIONS PTSD is a common consequence of RTAs. Liaison with accident and emergency departments would enhance the early detection and follow-up of children at risk of developing PTSD.
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