272 research outputs found

    The effect of metals on photosynthesis processes and diatom metrics of biofilm from a metal-contaminated river: A translocation experiment

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    With the aim of evaluating cause-effect relationships between metal pollution and biofilm structure and function, a translocation study was performed in a metal-polluted stream (the Osor stream "la riera d'Osor", NE Spain). Biofilm responses were measured as temporal changes in chl-a fluorescence parameters, pigment composition and diatom species composition. Biofilms from a non-polluted site were translocated to four downstream sites presenting a gradient of metal pollution, corresponding to scenarios of low and moderate metal pollution. Metal effects (Zn bioaccumulation, Fe bioaccumulation and Zn in water) were distinguished from other stressors (phosphate concentration in water). Based on the results obtained, a fast bioaccumulation of Zn (after few hours of exposure) was linked to a decrease in photosynthetic efficiency and an enhancement of mechanisms of protection through the xanthophyll cycle. After longer exposure, differences in Zn and Fe bioaccumulation and Zn water concentration between sites were linked to diatom community changes; decrease in diatom cell biovolume, along with a decrease in the IPS index of diatoms. Based on our results, we recommend including Zn in the list of priority pollutant substances of the European Water Framework Directive (2000/60/EC), due to its occurrence and toxicity. In addition, our study supports the use of chl-a fluorescence parameters together with the analysis of photosynthetic pigments of biofilms as suitable functional endpoints of early toxicity. Furthermore, diatom community studies are recommended for their clear response after chronic exposure. However, new diatom indices beyond the use of the IPS are required to increase their sensitivity to metal pollution, e.g. to identify the damage caused by moderate to low metal pollution.Este estudo foi financiado polo proxecto europeo KEYBIOEFFECTS (MRTN-CT-2006-035695) e o proxecto español: FLUVIALMULTISTRESS (CTM2009-14111-CO2-01).S

    Complications and treatment errors in periodontal therapy in medically compromised patients

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    Patients who are medically compromised may be at an increased risk of complications and treatment errors following periodontal therapy. A review of the evidence on the topic is presented, in relation to the type of complication reported, of periodontal treatment, and of patients' medical status. Further, a framework for risk assessment and appropriate treatment modifications is introduced, with the aim of facilitating the management of patients with existing comorbidities and reducing the incidence of treatment complications

    Recent histories of six productive lakes in the Irish Ecoregion based on multiproxy palaeolimnological evidence

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    This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s10750-006-0243-8Palaeolimnological data from six mesotrophic, eutrophic and hypertrophic lakes in the Irish Ecoregion, in the form of microfossil (cladocera, diatoms and pollen) and sediment chemistry data from radiometrically dated sediment cores, were used to reconstruct past variations in lake water quality and catchment conditions. Basal sediments from sediment cores from the six sites ranged in age from the late 18th century to the early 20th century. A weighted averaging partial least squares regression model was developed to reconstruct past epilimnetic total phosphorus concentrations. The results indicate that all but one of the study sites currently are in a far more productive state compared with the beginning of the sediment core record and that those same five lakes have experienced accelerated enrichment post c. 1980. Two of the sites demonstrated long-term enrichment, in one case beginning in the late 19th century, while both eutrophication and oligotrophication have occurred at three sites. The results highlight the difficulties in applying a general temporal end-point for reference conditions and demonstrate that productive lakes in the Irish Ecoregion have complex, locally specific and often long histories of enrichment. These may not be responsive to reduced external loadings of phosphorus and, as a result, restoration could prove particularly challenging. The results also provide evidence of the ways in which palaeolimnological techniques can assist implementation of the EU Water Framework Directive.Environmental Protection Agency (EPA) project # 2002-W-LS/7S

    Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

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    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

    Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

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    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

    Temporal profile of body temperature in acute ischemic stroke: relation to stroke severity and outcome

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    BACKGROUND: Pyrexia after stroke (temperature ≥37.5°C) is associated with poor prognosis, but information on timing of body temperature changes and relationship to stroke severity and subtypes varies. METHODS: We recruited patients with acute ischemic stroke, measured stroke severity, stroke subtype and recorded four-hourly tympanic (body) temperature readings from admission to 120 hours after stroke. We sought causes of pyrexia and measured functional outcome at 90 days. We systematically summarised all relevant previous studies. RESULTS: Amongst 44 patients (21 males, mean age 72 years SD 11) with median National Institute of Health Stroke Score (NIHSS) 7 (range 0–28), 14 had total anterior circulation strokes (TACS). On admission all patients, both TACS and non-TACS, were normothermic (median 36.3°C vs 36.5°C, p=0.382 respectively) at median 4 hours (interquartile range, IQR, 2–8) after stroke; admission temperature and NIHSS were not associated (r(2)=0.0, p=0.353). Peak temperature, occurring at 35.5 (IQR 19.0 to 53.8) hours after stroke, was higher in TACS (37.7°C) than non-TACS (37.1°C, p<0.001) and was associated with admission NIHSS (r(2)=0.20, p=0.002). Poor outcome (modified Rankin Scale ≥3) at 90 days was associated with higher admission (36.6°C vs. 36.2°C p=0.031) and peak (37.4°C vs. 37.0°C, p=0.016) temperatures. Sixteen (36%) patients became pyrexial, in seven (44%) of whom we found no cause other than the stroke. CONCLUSIONS: Normothermia is usual within the first 4 hours of stroke. Peak temperature occurs at 1.5 to 2 days after stroke, and is related to stroke severity/subtype and more closely associated with poor outcome than admission temperature. Temperature-outcome associations after stroke are complex, but normothermia on admission should not preclude randomisation of patients into trials of therapeutic hypothermia

    A Delphi Consensus Study

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    Funding Information: We sincerely thank all the experts who participated in this Delphi study for their time and for sharing their expertise. All Delphi experts qualify for authorship based on the fact that they were involved in data collection and all critically appraised the final manuscript for important intellectual content. See Appendix B for the names of the Delphi experts. Publisher Copyright: © 2021 The AuthorsObjective: No dedicated studies have been performed on the optimal management of patients with an acute stroke related to carotid intervention nor is there a solid recommendation given in the European Society for Vascular Surgery guideline. By implementation of an international expert Delphi panel, this study aimed to obtain expert consensus on the optimal management of in hospital stroke occurring during or following CEA and to provide a practical treatment decision tree. Methods: A four round Delphi consensus study was performed including 31 experts. The aim of the first round was to investigate whether the conceptual model indicating the traditional division between intra- and post-procedural stroke in six phases was appropriate, and to identify relevant clinical responses during these six phases. In rounds 2, 3, and 4, the aim was to obtain consensus on the optimal response to stroke in each predefined setting. Consensus was reached in rounds 1, 3, and 4 when ≥ 70% of experts agreed on the preferred clinical response and in round 2 based on a Likert scale when a median of 7 – 9 (most adequate response) was given, IQR ≤ 2. Results: The experts agreed (> 80%) on the use of the conceptual model. Stroke laterality and type of anaesthesia were included in the treatment algorithm. Consensus was reached in 17 of 21 scenarios (> 80%). Perform diagnostics first for a contralateral stroke in any phase, and for an ipsilateral stroke during cross clamping, or apparent stroke after leaving the operation room. For an ipsilateral stroke during the wake up phase, no formal consensus was achieved, but 65% of the experts would perform diagnostics first. A CT brain combined with a CTA or duplex ultrasound of the carotid arteries should be performed. For an ipsilateral intra-operative stroke after flow restoration, the carotid artery should be re-explored immediately (75%). Conclusion: In patients having a stroke following carotid endarterectomy, expedited diagnostics should be performed initially in most phases. In patients who experience an ipsilateral intra-operative stroke following carotid clamp release, immediate re-exploration of the index carotid artery is recommended.publishersversionpublishe

    Neuroprotection or Increased Brain Damage Mediated by Temperature in Stroke Is Time Dependent

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    The control of temperature during the acute phase of stroke may be a new therapeutic target that can be applied in all stroke patients, however therapeutic window or timecourse of the temperature effect is not well established. Our aim is to study the association between changes in body temperature in the first 72 hours and outcome in patients with ischemic (IS) and hemorrhagic (ICH) stroke. We prospectively studied 2931 consecutive patients (2468 with IS and 463 with ICH). Temperature was obtained at admission, and at 24, 48 and 72 hours after admission. Temperature was categorized as low (<36°C), normal (36–37°C) and high (>37°C). As the main variable, we studied functional outcome at 3 months determined by modified Rankin Scale
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