Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
1.
Microb Ecol ; 76(3): 680-694, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29504072

RESUMO

Arcellinida (testate lobose amoebae), a group of benthic protists, were examined from 46 sediment-water interface samples collected from oligotrophic Oromocto Lake, New Brunswick, Canada. To assess (1) assemblage homogeneity at a sub-meter spatial scale and (2) the necessity for collecting samples from multiple stations during intra-lake surveys; multiple samples were collected from three stations (quadrats 1, 2, and 3) across the north basin of Oromocto Lake, with quadrat 1 (n = 16) being the furthest to the west, quadrat 2 (n = 15) situated closer to the center of the basin, and quadrat 3 (n = 15) positioned 300 m south of the mouth of Dead Brook, an inlet stream. Results from cluster analysis and non-metric multidimensional scaling (NMDS) analysis identified two major Arcellinida assemblages, A1 and A2, the latter containing two sub-assemblages (A2a and A2b). Redundancy analysis and variance partitioning results indicated that seven statistically significant environmental variables (K, S, Sb, Ti, Zn, Fe, and Mn) explained 41.5% of the total variation in the Arcellinida distribution. Iron, Ti and K, indicators of detrital runoff, had the greatest influence on assemblage variance. The results of this study reveal that closely spaced samples (~ 10 cm) in an open-water setting are comprised of homogenous arcellinidan assemblages, indicating that replicate sampling is not required. The results, however, must be tempered with respect to the various water properties and physical characteristics that comprise individual lakes as collection of several samples may likely be necessary when sampling multiple sites of a lake basin characterized by varying water depths (e.g., littoral zone vs. open water), or lakes impacted by geogenic or anthropogenic stressors (e.g., eutrophication, or industrial contamination).


Assuntos
Amoeba/isolamento & purificação , Lagos/parasitologia , Amoeba/classificação , Amoeba/genética , Biodiversidade , Canadá , Monitoramento Ambiental , Sedimentos Geológicos/química , Sedimentos Geológicos/parasitologia , Ferro/análise , Lagos/química , Filogenia
2.
Microb Ecol ; 72(1): 130-149, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27026100

RESUMO

Arcellininids (testate amoebae) were examined from 61 surface sediment samples collected from 59 lakes in the vicinity of former gold mines, notably Giant Mine, near Yellowknife, Northwest Territories, Canada to determine their utility as bioindicators of arsenic (As), which occurs both as a byproduct of gold extraction at mines in the area and ore-bearing outcrops. Cluster analysis (Q-R-mode) and detrended correspondence analysis (DCA) reveal five arcellininid assemblages, three of which are related to varying As concentrations in the sediment samples. Redundancy analysis (RDA) showed that 14 statistically significant environmental parameters explained 57 % of the variation in faunal distribution, while partial RDA indicated that As had the greatest influence on assemblage variance (10.7 %; p < 0.10). Stress-indicating species (primarily centropyxids) characterized the faunas of samples with high As concentrations (median = 121.7 ppm, max > 10000 ppm, min = 16.1 ppm, n = 32), while difflugiid dominated assemblages were prevalent in substrates with relatively low As concentrations (median = 30.2 ppm, max = 905.2 ppm, min = 6.3 ppm, n = 20). Most of the lakes with very high As levels are located downwind (N and W) of the former Giant Mine roaster stack where refractory ore was roasted and substantial quantities of As were released (as As2O3) to the atmosphere in the first decade of mining. This spatial pattern suggests that a significant proportion of the observed As, in at least these lakes, are industrially derived. The results of this study highlight the sensitivity of Arcellinina to As and confirm that the group has considerable potential for assessing the impact of As contamination on lakes.


Assuntos
Amoeba/metabolismo , Arsênio/análise , Monitoramento Ambiental , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Amoeba/classificação , Amoeba/isolamento & purificação , Trióxido de Arsênio , Arsenicais , Canadá , Análise por Conglomerados , Ouro , Lagos/química , Mineração , Óxidos
3.
Br J Nurs ; 30(4): S3, 2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33641397
4.
Microb Ecol ; 68(2): 299-313, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24728526

RESUMO

Winter deicing operations occur extensively in mid- to high-latitude metropolitan regions around the world and result in a significant reduction in road accidents. Deicing salts can, however, pose a major threat to water quality and aquatic organisms. In this paper, we examine the utility of Arcellacea (testate amoebae) for monitoring lakes that have become contaminated by winter deicing salts, particularly sodium chloride. We analysed 50 sediment samples and salt-related water property variables (chloride concentrations; conductivity) from 15 lakes in the Greater Toronto Area and adjacent areas of southern Ontario, Canada. The sampled lakes included lakes in proximity to major highways and suburban roads and control lakes in forested settings away from road influences. Samples from the most contaminated lakes, with chloride concentrations in excess of 400 mg/l and conductivities of >800 µS/cm, were dominated by species typically found in brackish and/or inhospitable lake environments and by lower faunal diversities (lowest Shannon diversity index values) than samples with lower readings. Q-R-mode cluster analysis and detrended correspondence analysis (DCA) resulted in the recognition of four assemblage groupings. These reflect varying levels of salt contamination in the study lakes, along with other local influences, including nutrient loading. The response to nutrients can, however, be isolated if the planktic eutrophic indicator species Cucurbitella tricuspis is removed from the counts. The findings show that the group has considerable potential for biomonitoring in salt-contaminated lakes, and their presence in lake sediment cores may provide significant insights into long-term benthic community health, which is integral for remedial efforts.


Assuntos
Amoeba/crescimento & desenvolvimento , Monitoramento Ambiental/métodos , Cloreto de Sódio/análise , Poluentes Químicos da Água/análise , Amoeba/isolamento & purificação , Análise por Conglomerados , Lagos/química , Lagos/microbiologia , Ontário
5.
Br J Nurs ; 23(16): S4, S6, S8 passim, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25203854

RESUMO

Chemotherapy is increasingly being administered as a treatment for cancer and with it are a number of possible side effects. One, which has a negative impact on a patient's quality of life and their self-esteem, is that of chemotherapy-induced alopecia (CIA). A side effect of which, for some, could be prevented by the use of scalp cooling, dependent on the regimen being administered and patient choice. This article explores the issue of CIA from the patient's perspective and scalp cooling as a preventative measure, along with a review of the evidence around the risk associated with developing scalp metastases following scalp cooling. It also discusses why scalp cooling should be available for both male and female patients; along with the potential impact scalp cooling may have on clinical areas delivering chemotherapy.


Assuntos
Alopecia/induzido quimicamente , Alopecia/prevenção & controle , Antineoplásicos/efeitos adversos , Hipotermia Induzida/métodos , Couro Cabeludo , Alopecia/psicologia , Feminino , Cabelo/crescimento & desenvolvimento , Humanos , Masculino , Neoplasias/tratamento farmacológico , Seleção de Pacientes , Fatores Sexuais
6.
Br J Nurs ; 22(17): S6 -12, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24067273

RESUMO

AIMS: This article reviews the efficacy and place in therapy of dexrazoxane (Savene®) for the treatment of anthracycline extravasation, highlighting the lack of inclusion of Savene in most UK cancer network and organisational treatment guidelines. Here we offer advice to nurses on making a case to ensure the availability of Savene. KEY FINDINGS: In 2010, the UK National Extravasation Information Service (NEXIS) green card scheme reported that anthracyclines were the second most common agent involved in extravasations, but they carry the greatest risk to the patient because of their potentially serious consequences. Anthracycline extravasations therefore require prompt and effective treatment. Due to the infrequent occurrence of anthracycline extravasations, their accidental nature and ethical considerations, conducting randomised controlled clinical trials in this therapy area is not possible. As treatment decisions should always be made on patient-specific factors, health professionals need to demonstrate the rationale for choosing a particular course of action when presented with an anthracycline extravasation, especially when we are moving into an era of increased medical litigation. There are several possible treatment options, some of which require demonstrable local core competencies in order to be considered for a particular patient. Based on the available evidence, Savene-the only licensed antidote-is recommended as an effective management strategy for anthracycline extravasation and should be made available in all settings where chemotherapy is administered. However, a high percentage of nurses administering chemotherapy still do not have access to Savene, as it has not been included in their local guidelines for the management of extravasations. Thus, in a large part of the UK, this important treatment option is not available, leaving a significant unmet need (Figure 1). CONCLUSIONS: As nurses play a key role in the prevention, detection, and management of extravasations, they should also assume a key role in ensuring that their local protocols include all appropriate management strategies. Where appropriate, if Savene is not included in the treatment guidelines, nurses should feel empowered to encourage their trust and Specialist Commissioning Groups (SCGs) to make it available, and thus minimise the serious risks associated with anthracycline extravasations.


Assuntos
Antraciclinas/efeitos adversos , Antineoplásicos/efeitos adversos , Dexrazoxano/uso terapêutico , Extravasamento de Materiais Terapêuticos e Diagnósticos/tratamento farmacológico , Extravasamento de Materiais Terapêuticos e Diagnósticos/enfermagem , Neoplasias/tratamento farmacológico , Enfermagem Oncológica/normas , Inibidores da Topoisomerase II/uso terapêutico , Extravasamento de Materiais Terapêuticos e Diagnósticos/prevenção & controle , Humanos , Guias de Prática Clínica como Assunto , Fatores de Risco , Reino Unido
7.
Br J Nurs ; 21(17): S3, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23123696

RESUMO

The end of the summer in the professional cancer calendar always seems to signal the start of conference season, with many UK, European and international conferences taking place. Key conferences include those held by the International Society of Nursing in Cancer Care (ISNCC) in Prague this year, the European Society for Medical Oncology (ESMO) in Vienna, and the European Cancer Congress in Amsterdam, within the UK, October sees the joint United Kingdom Oncology Nursing Society (UKONS) and British Oncology Pharmacy Association (BOPA) conference at Harrogate.


Assuntos
Neoplasias/terapia , Humanos , Sociedades Médicas , Reino Unido
8.
Br J Nurs ; 20(10): S4-11, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21647004

RESUMO

This article provides insight into the growth cycle of a hair follicle and the potential impact chemotherapy agents can have on this process, which often results in hair loss (alopecia). It explores the psychological consequences of chemotherapy-induced alopecia for an individual as a result of the perceptions of others as well as an individual's perception of his or her self-image. Despite the development of various forms of scalp cooling, chemotherapy-induced alopecia remains a major side effect for patients receiving chemotherapy; however, there have been improvements in wig provision and changing public opinion relating to baldness. Although chemotherapy-induced alopecia affects both males and females and all age groups, this article focuses on the potential impact for patients receiving chemotherapy as a form of treatment for breast cancer. As professionals we need to understand the social significance of hair in relation to a person's outward presentation and social interactions, along with the possible psychological implications of a person losing his or her bodily hair, and not just the head hair. We must aim to minimize the distress alopecia can cause by: ensuring we provide patients with up-to-date verbal and written information to enable them to prepare for losing their hair; helping them to preserve their self-image and minimize the psychological consequences of hair loss while receiving chemotherapy; and preparing them for their hair re-growth following completion of chemotherapy.


Assuntos
Alopecia/induzido quimicamente , Antineoplásicos/efeitos adversos , Alopecia/prevenção & controle , Alopecia/psicologia , Humanos , Hipotermia Induzida
9.
Br J Nurs ; 25(10): S30, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27231749
10.
Br J Nurs ; 25(10): S3, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27231748
11.
Br J Nurs ; 20(17): S16, S18-22, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22067533

RESUMO

This article highlights the importance of being knowledgeable about anthracycline extravasations, including their prevention, early detection, and prompt and effective management. It also emphasizes the need for chemotherapy nurses to document and report all extravasations when they occur, summarizes the current management options, and offers recommendations for clinical practice. Extravasation refers to the unintentional administration of an agent into the surrounding tissue instead of the venous system; in this case, vesicant chemotherapy. Anthracycline extravasations can lead to significant and lasting tissue damage, infection, pain, and functional impairment; they remain a feared consequence for both the patient receiving the chemotherapy and the nurse administering it. The management of anthracycline extravasations remains a constant challenge to the professionals caring for the patient. One of these challenges is the lack of evidence for many of the treatment options available. The systemic antidote Savene® is the only approved treatment for anthracycline extravasations. It has proved highly efficacious and well-tolerated in prospective clinical studies and in routine clinical practice. Despite national and international professional organizations recommending Savene in their extravasation guidelines, many cancer networks in England still exclude it from their local protocol. Funding decisions regarding the use of supportive treatments are often made on the basis of clinical need; it is, therefore, imperative that nurses promptly report all extravasations or they will remain unknown and management of extravasations will not improve.


Assuntos
Antraciclinas/efeitos adversos , Antibióticos Antineoplásicos/efeitos adversos , Extravasamento de Materiais Terapêuticos e Diagnósticos/terapia , Adulto , Idoso , Antraciclinas/administração & dosagem , Antibióticos Antineoplásicos/administração & dosagem , Antídotos/uso terapêutico , Quelantes/uso terapêutico , Dimetil Sulfóxido/uso terapêutico , Inglaterra , Epirubicina/efeitos adversos , Extravasamento de Materiais Terapêuticos e Diagnósticos/enfermagem , Feminino , Sequestradores de Radicais Livres/uso terapêutico , Humanos , Injeções Intravenosas/efeitos adversos , Injeções Intravenosas/enfermagem , Diagnóstico de Enfermagem , Razoxano/uso terapêutico , Fatores de Risco
14.
Eur J Protistol ; 72: 125645, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31790921

RESUMO

Arcellinida (lobose testate amoebae) are abundant and diverse in many ecosystems, especially in moist to aquatic environments. Molecular phylogeny has shown that overall test morphology (e.g., spherical or elongate) is generally conserved in Arcellinida lineages, but the taxonomic value of other traits (e.g., size, ornamentation, mixotrophy/heterotrophy metabolism type) has not been systematically evaluated. Morphological and physiological traits that correspond to genetic differences likely represent adaptive traits of ecological significance. We combined high-resolution phylogenetics (NAD9-NAD7 genes) and advanced morphometrics to assess the phylogenetic signal of morphological traits of a group of elongate Difflugia species (Arcellinida). The phylogenetic analyses revealed two clades which could be reliably separated by test size and the presence/absence of mixotrophy. Differences in test size may reflect trophic level, with smaller organisms occupying lower trophic levels. In addition to having larger tests, elongate mixotrophic Difflugia are characterised by wide, flat bases and an inflation of the lower two thirds of their test. These morphological traits may provide additional volume for endosymbionts and/or increased surface area to aid light transmission. Our results showcase greater diversity within the elongate Difflugia and highlight morphological traits of ecological and evolutionary significance.


Assuntos
Amebozoários/classificação , Amebozoários/citologia , Filogenia , Amebozoários/metabolismo , Metabolismo Energético , Infecções por Protozoários/genética , Especificidade da Espécie
15.
Quat Sci Rev ; 28(23-24): 2342-2373, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20119485

RESUMO

Multidisciplinary investigations of the vegetational, faunal and sea-level history inferred from the infills of buried channels on the coast of eastern Essex have a direct bearing on the differentiation of MIS 11 and MIS 9 in continental records. New data are presented from Cudmore Grove, an important site on Mersea Island that can be linked to the terrace sequence of the River Thames. The vegetational history has been reconstructed from a pollen sequence covering much of the interglacial represented. The temperate nature of the climate is apparent from a range of fossil groups, including plant remains, vertebrates (especially the rich herpetofauna), molluscs and beetles, which all have strong thermophilous components. The beetle data have been used to derive a Mutual Climatic Range reconstruction, suggesting that mean July temperatures were about 2 degrees C warmer than modern values for southeast England, whereas mean January temperatures may have been slightly colder. The sea-level history has been reconstructed from the molluscs, ostracods and especially the diatoms, which indicate that the marine transgression occurred considerably earlier in the interglacial cycle than at the neighbouring Hoxnian site at Clacton. There are a number of palynological similarities between the sequence at Cudmore Grove and Clacton, especially the presence of Abies and the occurrence of Azolla filiculoides megaspores. Moreover, both sites have yielded Palaeolithic archaeology, indeed the latter is the type site of the Clactonian (flake-and-core) industry. However, the sites can be differentiated on the basis of mammalian biostratigraphy, new aminostratigraphic data, as well as the differences in the sea-level history. The combined evidence suggests that the infill of the channel at Cudmore Grove accumulated during MIS 9, whereas the deposits at Clacton formed during MIS 11. The infill of a much later channel, yielding non-marine molluscs and vertebrates including Hippopotamus, appears to have formed during the Ipswichian (MIS 5e). This evidence is compared with other important sites of late Middle Pleistocene age in Britain and elsewhere on the continent and the importance of a multidisciplinary approach is stressed.

16.
Front Physiol ; 10: 941, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31396106

RESUMO

Drosophila suzukii (Matsumara) also called Spotted Wing Drosophila (SWD), is an invasive pest species originally from Asia that has now spread widely across Europe and North America. The majority of drosophilids including the best known Drosophila melanogaster only breed on decaying fruits. On the contrary, the presence of a strong serrated ovipositor and behavioural and metabolic adaptations allow D. suzukii to lay eggs inside healthy, ripening fruits that are still on the plant. Here we present an analysis of the rhythmic locomotor activity behaviour of D. suzukii under several laboratory settings. Moreover, we identify the canonical clock neurons in this species by reporting the expression pattern of the major clock proteins in the brain. Interestingly, a fundamentally similar organisation of the clock neurons network between D. melanogaster and D. suzukii does not correspond to similar characteristics in rhythmic locomotor activity behaviour.

19.
PeerJ ; 6: e4850, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29915687

RESUMO

Frame Lake, located within the city of Yellowknife, Northwest Territories, Canada, has been identified as requiring significant remediation due to its steadily declining water quality and inability to support fish by the 1970s. Former gold mining operations and urbanization around the lake have been suspected as probable causes for the decline in water quality. While these land-use activities are well documented, little information is available regarding their impact on the lake itself. For this reason, Arcellinida, a group of shelled protozoans known to be reliable bioindicators of land-use change, were used to develop a hydroecological history of the lake. The purpose of this study was to use Arcellinida to: (1) document the contamination history of the lake, particularly related to arsenic (As) associated with aerial deposition from mine roaster stacks; (2) track the progress of water quality deterioration in Frame Lake related to mining, urbanization and other activities; and (3) identify any evidence of natural remediation within the lake. Arcellinida assemblages were assessed at 1-cm intervals through the upper 30 cm of a freeze core obtained from Frame Lake. The assemblages were statistically compared to geochemical and loss-on-ignition results from the core to document the contamination and degradation of conditions in the lake. The chronology of limnological changes recorded in the lake sediments were derived from 210Pb, 14C dating and known stratigraphic events. The progress of urbanization near the lake was tracked using aerial photography. Using Spearman correlations, the five most significant environmental variables impacting Arcellinida distribution were identified as minerogenics, organics, As, iron and mercury (p < 0.05; n = 30). Based on CONISS and ANOSIM analysis, three Arcellinida assemblages are identified. These include the Baseline Limnological Conditions Assemblage (BLCA), ranging from 17-30 cm and deposited in the early Holocene >7,000 years before present; the As Contamination Assemblage (ACA), ranging from 7-16 cm, deposited after ∼1962 when sedimentation began in the lake again following a long hiatus that spanned to the early Holocene; and the Eutrophication Assemblage (EA), ranging from 1-6 cm, comprised of sediments deposited after 1990 following the cessation of As and other metal contaminations. The EA developed in response to nutrient-rich waters entering the lake derived from the urbanization of the lake catchment and a reduction in lake circulation associated with the development at the lake outlet of a major road, later replaced by a causeway with rarely open sluiceways. The eutrophic condition currently charactering the lake-as evidenced by a population explosion of eutrophication indicator taxa Cucurbitella tricuspis-likely led to a massive increase in macrophyte growth and winter fish-kills. This ecological shift ultimately led to a system dominated by Hirudinea (leeches) and cessation of the lake as a recreational area.

20.
PLoS One ; 13(6): e0199872, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29953559

RESUMO

We examined late Holocene (ca. 3300 yr BP to present-day) climate variability in the central Northwest Territories (Canadian Subarctic) using a diatom and sedimentological record from Danny's Lake (63.48ºN, 112.54ºW), located 40 km southwest of the modern-day treeline. High-resolution sampling paired with a robust age model (25 radiocarbon dates) allowed for the examination of both lake hydroecological conditions (30-year intervals; diatoms) and sedimentological changes in the watershed (12-year intervals; grain size records) over the late Holocene. Time series analysis of key lake ecological indicators (diatom species Aulacoseira alpigena, Pseudostaurosira brevistriata and Achnanthidium minutissimum) and sedimentological parameters, reflective of catchment processes (coarse silt fraction), suggests significant intermittent variations in turbidity, pH and light penetration within the lake basin. In the diatom record, we observed discontinuous periodicities in the range of ca. 69, 88-100, 115-132, 141-188, 562, 750 and 900 years (>90% and >95% confidence intervals), whereas the coarse silt fraction was characterized by periodicities in the >901 and <61-year range (>95% confidence interval). Periodicities in the proxy data from the Danny's Lake sediment core align with changes in total solar irradiance over the past ca. 3300 yr BP and we hypothesize a link to the Suess Cycle, Gleissberg Cycle and Pacific Decadal Oscillation via occasional inland propagation of shifting air masses over the Pacific Ocean. This research represents an important baseline study of the underlying causes of climate variability in the Canadian Subarctic and provides details on the long-term climate variability that has persisted in this region through the past three thousand years.


Assuntos
Mudança Climática , Diatomáceas , Fósseis , Lagos , Canadá
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA