Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
1.
PLoS One ; 18(6): e0260903, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37314989

RESUMO

Surf zones are highly dynamic marine ecosystems that are subject to increasing anthropogenic and climatic pressures, posing multiple challenges for biomonitoring. Traditional methods such as seines and hook and line surveys are often labor intensive, taxonomically biased, and can be physically hazardous. Emerging techniques, such as baited remote underwater video (BRUV) and environmental DNA (eDNA) are promising nondestructive tools for assessing marine biodiversity in surf zones of sandy beaches. Here we compare the relative performance of beach seines, BRUV, and eDNA in characterizing community composition of bony (teleost) and cartilaginous (elasmobranch) fishes of surf zones at 18 open coast sandy beaches in southern California. Seine and BRUV surveys captured overlapping, but distinct fish communities with 50% (18/36) of detected species shared. BRUV surveys more frequently detected larger species (e.g. sharks and rays) while seines more frequently detected one of the most abundant species, barred surfperch (Amphistichus argenteus). In contrast, eDNA metabarcoding captured 88.9% (32/36) of all fishes observed in seine and BRUV surveys plus 57 additional species, including 15 that frequent surf zone habitats. On average, eDNA detected over 5 times more species than BRUVs and 8 times more species than seine surveys at a given site. eDNA approaches also showed significantly higher sensitivity than seine and BRUV methods and more consistently detected 31 of the 32 (96.9%) jointly observed species across beaches. The four species detected by BRUV/seines, but not eDNA were only resolved at higher taxonomic ranks (e.g. Embiotocidae surfperches and Sygnathidae pipefishes). In frequent co-detection of species between methods limited comparisons of richness and abundance estimates, highlighting the challenge of comparing biomonitoring approaches. Despite potential for improvement, results overall demonstrate that eDNA can provide a cost-effective tool for long-term surf zone monitoring that complements data from seine and BRUV surveys, allowing more comprehensive surveys of vertebrate diversity in surf zone habitats.


Assuntos
Monitoramento Biológico , DNA Ambiental , Animais , Ecossistema , Peixes/genética , Biodiversidade , DNA Ambiental/genética
2.
J Anim Ecol ; 90(9): 2077-2093, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34002377

RESUMO

Although long-term ecological stability is often discussed as a community attribute, it is typically investigated at the species level (e.g. density, biomass), or as a univariate metric (e.g. species diversity). To provide a more comprehensive assessment of long-term community stability, we used a multivariate similarity approach that included all species and their relative abundances. We used data from 74 sites sampled annually from 2006 to 2017 to examine broad temporal and spatial patterns of change within rocky intertidal communities along the west coast of North America. We explored relationships between community change (inverse of stability) and the following potential drivers of change/stability: (a) marine heatwave events; (b) three attributes of biodiversity: richness, diversity and evenness and (c) presence of the mussel, Mytilus californianus, a dominant space holder and foundation species in this system. At a broad scale, we found an inverse relationship between community stability and elevated water temperatures. In addition, we found substantial differences in stability among regions, with lower stability in the south, which may provide a glimpse into the patterns expected with a changing climate. At the site level, community stability was linked to high species richness and, perhaps counterintuitively, to low evenness, which could be a consequence of the dominance of mussels in this system. Synthesis. Assessments of long-term stability at the whole-community level are rarely done but are key to a comprehensive understanding of the impacts of climate change. In communities structured around a spatially dominant species, long-term stability can be linked to the stability of this 'foundation species', as well as to traditional predictors, such as species richness.


Assuntos
Bivalves , Ecossistema , Animais , Biodiversidade , Biomassa , América do Norte
3.
Ecol Evol ; 9(8): 4720-4732, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31031938

RESUMO

For over 10,000 years, black abalone (Haliotis cracherodii) were an important resource in southern California, first for coastal Native Americans, then beginning in the nineteenth century, as one of the state's first commercial shellfisheries. By 1993, after years of heavy fishing, rising sea surface temperatures (SST), and the spread of withering syndrome (WS), black abalone populations declined dramatically, resulting in the closure of the Alta California fishery. After nearly 25 years of management and recovery efforts, black abalone are showing signs of ecological rebound along some Channel Island shorelines. These include the presence of juvenile abalone and increasing densities, largely from data collected by Channel Islands National Park (CINP) monitoring efforts that began in 1985.In an effort to apply deeper historical perspectives to modern fisheries management and restoration, we analyzed black abalone size data from San Miguel Island at prehistoric and historical archeological sites spanning the last 10,000 years and compared these populations to those described by CINP biologists between 1985 and 2013.We found a statistically significant relationship between SST and black abalone size distributions during the ancient record, along with dramatic shifts in population size structure toward larger individuals between the nineteenth century and modern periods. A pattern of larger mean black abalone sizes was identified during warm SSTs, when compared against intervals of cooler SSTs.Synthesis and applications. Our study provides a deep historical perspective of abalone population size distributions, patterns within these distributions through time, and parallels to modern abalone populations. Our results may help managers determine whether the current (and future) size and age structure of intertidal black abalone populations around the northern Channel Islands are "natural" and healthy, measured against the 10,000 year history of black abalone fishing in southern California.

4.
Lancet ; 393(10166): 51-60, 2019 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-30449623

RESUMO

BACKGROUND: The incidence of human papillomavirus (HPV)-positive oropharyngeal cancer, a disease affecting younger patients, is rapidly increasing. Cetuximab, an epidermal growth factor receptor inhibitor, has been proposed for treatment de-escalation in this setting to reduce the toxicity of standard cisplatin treatment, but no randomised evidence exists for the efficacy of this strategy. METHODS: We did an open-label randomised controlled phase 3 trial at 32 head and neck treatment centres in Ireland, the Netherlands, and the UK, in patients aged 18 years or older with HPV-positive low-risk oropharyngeal cancer (non-smokers or lifetime smokers with a smoking history of <10 pack-years). Eligible patients were randomly assigned (1:1) to receive, in addition to radiotherapy (70 Gy in 35 fractions), either intravenous cisplatin (100 mg/m2 on days 1, 22, and 43 of radiotherapy) or intravenous cetuximab (400 mg/m2 loading dose followed by seven weekly infusions of 250 mg/m2). The primary outcome was overall severe (grade 3-5) toxicity events at 24 months from the end of treatment. The primary outcome was assessed by intention-to-treat and per-protocol analyses. This trial is registered with the ISRCTN registry, number ISRCTN33522080. FINDINGS: Between Nov 12, 2012, and Oct 1, 2016, 334 patients were recruited (166 in the cisplatin group and 168 in the cetuximab group). Overall (acute and late) severe (grade 3-5) toxicity did not differ significantly between treatment groups at 24 months (mean number of events per patient 4·8 [95% CI 4·2-5·4] with cisplatin vs 4·8 [4·2-5·4] with cetuximab; p=0·98). At 24 months, overall all-grade toxicity did not differ significantly either (mean number of events per patient 29·2 [95% CI 27·3-31·0] with cisplatin vs 30·1 [28·3-31·9] with cetuximab; p=0·49). However, there was a significant difference between cisplatin and cetuximab in 2-year overall survival (97·5% vs 89·4%, hazard ratio 5·0 [95% CI 1·7-14·7]; p=0·001) and 2-year recurrence (6·0% vs 16·1%, 3·4 [1·6-7·2]; p=0·0007). INTERPRETATION: Compared with the standard cisplatin regimen, cetuximab showed no benefit in terms of reduced toxicity, but instead showed significant detriment in terms of tumour control. Cisplatin and radiotherapy should be used as the standard of care for HPV-positive low-risk patients who are able to tolerate cisplatin. FUNDING: Cancer Research UK.


Assuntos
Antineoplásicos/uso terapêutico , Cetuximab/uso terapêutico , Cisplatino/uso terapêutico , Neoplasias Orofaríngeas/terapia , Carcinoma de Células Escamosas de Cabeça e Pescoço/terapia , Doença Aguda , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Cetuximab/administração & dosagem , Cetuximab/efeitos adversos , Quimiorradioterapia/efeitos adversos , Quimiorradioterapia/métodos , Cisplatino/administração & dosagem , Cisplatino/efeitos adversos , Esquema de Medicação , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Orofaríngeas/patologia , Neoplasias Orofaríngeas/virologia , Infecções por Papillomavirus/complicações , Radioterapia de Intensidade Modulada/efeitos adversos , Radioterapia de Intensidade Modulada/métodos , Medição de Risco , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/virologia , Resultado do Tratamento
5.
PLoS One ; 13(3): e0192870, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29558484

RESUMO

Disease outbreaks can have substantial impacts on wild populations, but the often patchy or anecdotal evidence of these impacts impedes our ability to understand outbreak dynamics. Recently however, a severe disease outbreak occurred in a group of very well-studied organisms-sea stars along the west coast of North America. We analyzed nearly two decades of data from a coordinated monitoring effort at 88 sites ranging from southern British Columbia to San Diego, California along with 2 sites near Sitka, Alaska to better understand the effects of sea star wasting disease (SSWD) on the keystone intertidal predator, Pisaster ochraceus. Quantitative surveys revealed unprecedented declines of P. ochraceus in 2014 and 2015 across nearly the entire geographic range of the species. The intensity of the impact of SSWD was not uniform across the affected area, with proportionally greater population declines in the southern regions relative to the north. The degree of population decline was unrelated to pre-outbreak P. ochraceus density, although these factors have been linked in other well-documented disease events. While elevated seawater temperatures were not broadly linked to the initial emergence of SSWD, anomalously high seawater temperatures in 2014 and 2015 might have exacerbated the disease's impact. Both before and after the onset of the SSWD outbreak, we documented higher recruitment of P. ochraceus in the north than in the south, and while some juveniles are surviving (as evidenced by transition of recruitment pulses to larger size classes), post-SSWD survivorship is lower than during pre-SSWD periods. In hindsight, our data suggest that the SSWD event defied prediction based on two factors found to be important in other marine disease events, sea water temperature and population density, and illustrate the importance of surveillance of natural populations as one element of an integrated approach to marine disease ecology. Low levels of SSWD-symptomatic sea stars are still present throughout the impacted range, thus the outlook for population recovery is uncertain.


Assuntos
Doenças dos Animais/epidemiologia , Estrelas-do-Mar , Alaska , Animais , Dinâmica Populacional
6.
Br J Oral Maxillofac Surg ; 54(7): 741-5, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27156234

RESUMO

We retrospectively reviewed the management at our centre of 25 patients with Merkel cell carcinoma (MCC) of the head and neck. We obtained details of the operation, including wide local excision, sentinel lymph node biopsy (SNB), neck dissection, postoperative radiotherapy, and clinical outcomes, from patients' records. All patients were white, 11 were men and 14 women, mean age at presentation 81 years (range 67-90). At the time of diagnosis, 18 patients had stage I disease, and 7 stage II disease. Twenty had wide local excision and radiotherapy, and 5 had wide local excision alone. Wide local excision and radiotherapy are successful treatments. In patients with no sign of metastases, SNB at the time of excision is a well-researched option and should be considered the gold standard of care.


Assuntos
Carcinoma de Célula de Merkel , Neoplasias Cutâneas , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Célula de Merkel/diagnóstico , Carcinoma de Célula de Merkel/terapia , Feminino , Humanos , Metástase Linfática , Masculino , Biópsia de Linfonodo Sentinela , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/terapia , Resultado do Tratamento
7.
Med Dosim ; 38(1): 18-24, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-22841937

RESUMO

UNLABELLED: Fluorine-18-fluorodeoxyglucose-positron emission tomography (¹8F-FDG-PET)-guided focal dose escalation in oropharyngeal cancer may potentially improve local control. We evaluated the feasibility of this approach using volumetric-modulated arc therapy (RapidArc) and compared these plans with fixed-field intensity-modulated radiotherapy (IMRT) focal dose escalation plans. MATERIALS AND METHODS: An initial study of 20 patients compared RapidArc with fixed-field IMRT using standard dose prescriptions. From this cohort, 10 were included in a dose escalation planning study. Dose escalation was applied to ¹8F-FDG-PET-positive regions in the primary tumor at dose levels of 5% (DL1), 10% (DL2), and 15% (DL3) above standard radical dose (65 Gy in 30 fractions). Fixed-field IMRT and double-arc RapidArc plans were generated for each dataset. Dose-volume histograms were used for plan evaluation and comparison. The Paddick conformity index (CI(Paddick)) and monitor units (MU) for each plan were recorded and compared. Both IMRT and RapidArc produced clinically acceptable plans and achieved planning objectives for target volumes. Dose conformity was significantly better in the RapidArc plans, with lower CI(Paddick) scores in both primary (PTV1) and elective (PTV2) planning target volumes (largest difference in PTV1 at DL3; 0.81 ± 0.03 [RapidArc] vs. 0.77 ± 0.07 [IMRT], p = 0.04). Maximum dose constraints for spinal cord and brainstem were not exceeded in both RapidArc and IMRT plans, but mean doses were higher with RapidArc (by 2.7 ± 1 Gy for spinal cord and 1.9 ± 1 Gy for brainstem). Contralateral parotid mean dose was lower with RapidArc, which was statistically significant at DL1 (29.0 vs. 29.9 Gy, p = 0.01) and DL2 (29.3 vs. 30.3 Gy, p = 0.03). MU were reduced by 39.8-49.2% with RapidArc (largest difference at DL3, 641 ± 94 vs. 1261 ± 118, p < 0.01). ¹8F-FDG-PET-guided focal dose escalation in oropharyngeal cancer is feasible with RapidArc. Compared with conventional fixed-field IMRT, RapidArc can achieve better dose conformity, improve contralateral parotid sparing, and uses fewer MU.


Assuntos
Carcinoma de Células Escamosas/diagnóstico por imagem , Carcinoma de Células Escamosas/radioterapia , Fluordesoxiglucose F18 , Neoplasias Orofaríngeas/diagnóstico por imagem , Neoplasias Orofaríngeas/radioterapia , Radioterapia Guiada por Imagem/métodos , Idoso , Fracionamento da Dose de Radiação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cintilografia , Compostos Radiofarmacêuticos , Dosagem Radioterapêutica , Resultado do Tratamento
8.
Histopathology ; 61(4): 629-43, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22882517

RESUMO

AIMS: The aim of this study was to devise a molecular classification for salivary duct carcinomas (SDCs) based on the similarities between SDCs and breast carcinomas and on characteristics of the microarray-based gene expression profiling-defined molecular subtypes of breast cancer. METHODS AND RESULTS: Forty-two pure salivary duct carcinomas, 35 of which contained an in-situ component as defined by histological review and/or immunohistochemical analysis, were stained with antibodies for oestrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR) and cytokeratin (CK) 5/6. Based on these markers, tumours were classified into HER2, luminal androgen receptor-positive, basal-like, luminal and indeterminate phenotype. Analysis revealed that 16.7%, 69%, 4.8%, 9.5% and 0% were of HER2, luminal androgen receptor-positive, basal-like, indeterminate and luminal phenotype, respectively. The in-situ and invasive components displayed the same molecular subtype in all but one case. CONCLUSION: Salivary duct carcinomas can be classified into molecular subgroups approximately equivalent to those in the breast. We also report on the existence of a subgroup of bona fide pure salivary duct carcinomas that have a 'basal-like' phenotype. Understanding the phenotypic complexity of SDCs may help to expedite the identification of novel therapeutic targets for these aggressive tumours.


Assuntos
Carcinoma in Situ/classificação , Carcinoma Ductal/classificação , Carcinoma/classificação , Neoplasias das Glândulas Salivares/classificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/análise , Carcinoma/genética , Carcinoma/patologia , Carcinoma in Situ/genética , Carcinoma in Situ/patologia , Carcinoma Ductal/genética , Carcinoma Ductal/patologia , Feminino , Humanos , Imuno-Histoquímica , Hibridização In Situ , Masculino , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Receptor ErbB-2/análise , Receptor ErbB-2/biossíntese , Receptor ErbB-2/genética , Receptores Androgênicos/análise , Receptores Androgênicos/biossíntese , Receptores Androgênicos/genética , Ductos Salivares/patologia , Neoplasias das Glândulas Salivares/genética , Neoplasias das Glândulas Salivares/patologia , Análise Serial de Tecidos , Transcriptoma
9.
N Engl J Med ; 366(18): 1674-85, 2012 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-22551128

RESUMO

BACKGROUND: It is not known whether low-dose radioiodine (1.1 GBq [30 mCi]) is as effective as high-dose radioiodine (3.7 GBq [100 mCi]) for treating patients with differentiated thyroid cancer or whether the effects of radioiodine (especially at a low dose) are influenced by using either recombinant human thyrotropin (thyrotropin alfa) or thyroid hormone withdrawal. METHODS: At 29 centers in the United Kingdom, we conducted a randomized noninferiority trial comparing low-dose and high-dose radioiodine, each in combination with either thyrotropin alfa or thyroid hormone withdrawal before ablation. Patients (age range, 16 to 80 years) had tumor stage T1 to T3, with possible spread to nearby lymph nodes but without metastasis. End points were the rate of success of ablation at 6 to 9 months, adverse events, quality of life, and length of hospital stay. RESULTS: A total of 438 patients underwent randomization; data could be analyzed for 421. Ablation success rates were 85.0% in the group receiving low-dose radioiodine versus 88.9% in the group receiving the high dose and 87.1% in the thyrotropin alfa group versus 86.7% in the group undergoing thyroid hormone withdrawal. All 95% confidence intervals for the differences were within ±10 percentage points, indicating noninferiority. Similar results were found for low-dose radioiodine plus thyrotropin alfa (84.3%) versus high-dose radioiodine plus thyroid hormone withdrawal (87.6%) or high-dose radioiodine plus thyrotropin alfa (90.2%). More patients in the high-dose group than in the low-dose group were hospitalized for at least 3 days (36.3% vs. 13.0%, P<0.001). The proportions of patients with adverse events were 21% in the low-dose group versus 33% in the high-dose group (P=0.007) and 23% in the thyrotropin alfa group versus 30% in the group undergoing thyroid hormone withdrawal (P=0.11). CONCLUSIONS: Low-dose radioiodine plus thyrotropin alfa was as effective as high-dose radioiodine, with a lower rate of adverse events. (Funded by Cancer Research UK; ClinicalTrials.gov number, NCT00415233.).


Assuntos
Radioisótopos do Iodo/administração & dosagem , Neoplasias da Glândula Tireoide/radioterapia , Tirotropina Alfa/uso terapêutico , Técnicas de Ablação/efeitos adversos , Técnicas de Ablação/psicologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Terapia Combinada , Feminino , Seguimentos , Humanos , Hipotireoidismo/etiologia , Radioisótopos do Iodo/efeitos adversos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Qualidade de Vida , Dosagem Radioterapêutica , Hormônios Tireóideos/sangue , Hormônios Tireóideos/uso terapêutico , Neoplasias da Glândula Tireoide/tratamento farmacológico , Neoplasias da Glândula Tireoide/cirurgia , Tireoidectomia , Tirotropina Alfa/efeitos adversos , Resultado do Tratamento , Adulto Jovem
10.
Biotechnol Bioeng ; 77(5): 495-516, 2002 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-11788949

RESUMO

In this study we describe a scheme for numerically calculating the effective diffusivity of cellular systems such as biofilms and tissues. This work extends previous studies in which we developed the macroscale representations of the transport equations for cellular systems based on the subcellular-scale transport and reaction processes. A finite-difference model is used to predict the effective diffusivity of a cellular system on the basis of the subcellular-scale geometry and transport parameters. The effective diffusivity is predicted for a complex three-dimensional structure that is based on laboratory observations of a biofilm, and these numerical predictions are compared with predictions from a simple analytical solution and with experimental data. Our results indicate that, under many practical circumstances, the simple analytical solution can be used to provide reasonable estimates of the effective diffusivity.


Assuntos
Biofilmes , Modelos Biológicos , Transporte Biológico/fisiologia , Biotecnologia , Difusão , Células Eucarióticas/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...