Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 75
Filtrar
1.
Biogeochemistry ; 135(1): 1-34, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-32009689

RESUMO

Continental shelf sediments are globally important for biogeochemical activity. Quantification of shelf-scale stocks and fluxes of carbon and nutrients requires the extrapolation of observations made at limited points in space and time. The procedure for selecting exemplar sites to form the basis of this up-scaling is discussed in relation to a UK-funded research programme investigating biogeochemistry in shelf seas. A three-step selection process is proposed in which (1) a target area representative of UK shelf sediment heterogeneity is selected, (2) the target area is assessed for spatial heterogeneity in sediment and habitat type, bed and water column structure and hydrodynamic forcing, and (3) study sites are selected within this target area encompassing the range of spatial heterogeneity required to address key scientific questions regarding shelf scale biogeochemistry, and minimise confounding variables. This led to the selection of four sites within the Celtic Sea that are significantly different in terms of their sediment, bed structure, and macrofaunal, meiofaunal and microbial community structures and diversity, but have minimal variations in water depth, tidal and wave magnitudes and directions, temperature and salinity. They form the basis of a research cruise programme of observation, sampling and experimentation encompassing the spring bloom cycle. Typical variation in key biogeochemical, sediment, biological and hydrodynamic parameters over a pre to post bloom period are presented, with a discussion of anthropogenic influences in the region. This methodology ensures the best likelihood of site-specific work being useful for up-scaling activities, increasing our understanding of benthic biogeochemistry at the UK-shelf scale.

2.
Biogeochemistry ; 135(1): 155-182, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-32009696

RESUMO

Results from a 1D setup of the European Regional Seas Ecosystem Model (ERSEM) biogeochemical model were compared with new observations collected under the UK Shelf Seas Biogeochemistry (SSB) programme to assess model performance and clarify elements of shelf-sea benthic biogeochemistry and carbon cycling. Observations from two contrasting sites (muddy and sandy) in the Celtic Sea in otherwise comparable hydrographic conditions were considered, with the focus on the benthic system. A standard model parameterisation with site-specific light and nutrient adjustments was used, along with modifications to the within-seabed diffusivity to accommodate the modelling of permeable (sandy) sediments. Differences between modelled and observed quantities of organic carbon in the bed were interpreted to suggest that a large part (>90%) of the observed benthic organic carbon is biologically relatively inactive. Evidence on the rate at which this inactive fraction is produced will constitute important information to quantify offshore carbon sequestration. Total oxygen uptake and oxic layer depths were within the range of the measured values. Modelled depth average pore water concentrations of ammonium, phosphate and silicate were typically 5-20% of observed values at the muddy site due to an underestimate of concentrations associated with the deeper sediment layers. Model agreement for these nutrients was better at the sandy site, which had lower pore water concentrations, especially deeper in the sediment. Comparison of pore water nitrate with observations had added uncertainty, as the results from process studies at the sites indicated the dominance of the anammox pathway for nitrogen removal; a pathway that is not included in the model. Macrofaunal biomasses were overestimated, although a model run with increased macrofaunal background mortality rates decreased macrofaunal biomass and improved agreement with observations. The decrease in macrofaunal biomass was compensated by an increase in meiofaunal biomass such that total oxygen demand remained within the observed range. The permeable sediment modification reproduced some of the observed behaviour of oxygen penetration depth at the sandy site. It is suggested that future development in ERSEM benthic modelling should focus on: (1) mixing and degradation rates of benthic organic matter, (2) validation of benthic faunal biomass against large scale spatial datasets, (3) incorporation of anammox in the benthic nitrogen cycle, and (4) further developments to represent permeable sediment processes.

3.
Med Vet Entomol ; 30(4): 426-434, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27670265

RESUMO

Bed bugs as pests of public health importance recently experienced a resurgence in populations throughout the U.S. and other countries. Consequently, recent research efforts have focused on improving understanding of bed bug physiology and behaviour to improve management. While few studies have investigated the visual capabilities of bed bugs, the present study focused specifically on eye morphology and spectral sensitivity. A 3-D imaging technique was used to document bed bug eye morphology from the first instar through adult and revealed morphological characteristics that differentiate the common bed bug from the tropical bed bug as well as sex-specific differences. Electrophysiological measurements were used to evaluate the spectral sensitivity of adult bed bugs. Male bed bugs were more responsive than females at some wavelengths. Electrophysiological studies provided evidence for at least one photoreceptor with a spectral sensitivity curve peak in the green (λmax 520 nm) region of the spectrum. The broadened long wavelength portion of the spectral sensitivity curve may potentially indicate another photoreceptor in the yellow-green (λmax 550 nm) portion of the spectrum or screening pigments. Understanding more about bed bug visual biology is vital for designing traps, which are an important component of integrated bed bug management.


Assuntos
Percevejos-de-Cama/anatomia & histologia , Percevejos-de-Cama/fisiologia , Olho Composto de Artrópodes/anatomia & histologia , Olho Composto de Artrópodes/fisiologia , Animais , Percevejos-de-Cama/crescimento & desenvolvimento , Olho Composto de Artrópodes/crescimento & desenvolvimento , Feminino , Masculino , Ninfa/anatomia & histologia , Ninfa/crescimento & desenvolvimento , Ninfa/fisiologia , Visão Ocular , Percepção Visual
4.
FEMS Microbiol Ecol ; 91(8): fiv092, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26220309

RESUMO

The geological storage of carbon dioxide (CO2) is expected to be an important component of future global carbon emission mitigation, but there is a need to understand the impacts of a CO2 leak on the marine environment and to develop monitoring protocols for leakage detection. In the present study, sediment cores were exposed to CO2-acidified seawater at one of five pH levels (8.0, 7.5, 7.0, 6.5 and 6.0) for 10 weeks. A bloom of Spirulina sp. and diatoms appeared on sediment surface exposed to pH 7.0 and 7.5 seawater. Quantitative PCR measurements of the abundance of 16S rRNA also indicated an increase within the pH 7.0 and 7.5 treatments after 10 weeks incubation. More detailed analysis of the microbial communities from the pH 7.0, 7.5 and 8.0 treatments confirmed an increase in the relative abundance of Spirulina sp. and Navicula sp. sequences, with changes in the relative abundance of major archaeal and bacterial groups also detected within the pH 7.0 treatment. A decreased flux of silicate from the sediment at this pH was also detected. Monitoring blooms of microphytobenthos may prove useful as an indicator of CO2 leakage within coastal areas.


Assuntos
Dióxido de Carbono/metabolismo , Diatomáceas/crescimento & desenvolvimento , Água do Mar/microbiologia , Spirulina/crescimento & desenvolvimento , Archaea/classificação , Archaea/genética , Sequência de Bases , Dióxido de Carbono/análise , DNA Arqueal/genética , DNA Bacteriano/genética , Eutrofização , Fenômenos Geológicos , Concentração de Íons de Hidrogênio , RNA Ribossômico 16S/genética , Água do Mar/química , Análise de Sequência de DNA
5.
Leukemia ; 27(6): 1310-5, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23459450

RESUMO

Peripheral arterial occlusive disease (PAOD) occurs in patients with chronic phase chronic myeloid leukemia (CML-CP) treated with tyrosine kinase inhibitors (TKIs). The risk of developing PAOD on TKI therapy is unknown and causality has not been established. Patients with CML-CP from three randomized phase III studies (IRIS, TOPS and ENESTnd) were divided into three cohorts: no TKI (cohort 1; n=533), nilotinib (cohort 2; n=556) and imatinib (cohort 3; n=1301). Patients with atherosclerotic risk factors were not excluded. Data were queried for terms indicative of PAOD. Overall, 3, 7 and 2 patients in cohorts 1, 2 and 3, respectively, had PAOD; 11/12 patients had baseline PAOD risk factors. Compared with that of cohort 1, exposure-adjusted risks of PAOD for cohorts 2 and 3 were 0.9 (95% CI, 0.2-3.3) and 0.1 (95% CI, 0.0-0.5), respectively. Multivariate logistic regression revealed that nilotinib had no impact on PAOD rates compared with no TKI, whereas imatinib had decreased rates of PAOD compared with no TKI. Nilotinib was associated with higher rates of PAOD versus imatinib. Baseline assessments, preferably within clinical studies, of PAOD and associated risk factors should occur when initiating TKI therapy in CML; patients should receive monitoring and treatment according to the standard of care for these comorbidities.


Assuntos
Antineoplásicos/uso terapêutico , Arteriopatias Oclusivas/complicações , Benzamidas/uso terapêutico , Leucemia Mielogênica Crônica BCR-ABL Positiva/complicações , Doença Arterial Periférica/complicações , Piperazinas/uso terapêutico , Pirimidinas/uso terapêutico , Idoso , Feminino , Humanos , Mesilato de Imatinib , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
6.
Mar Pollut Bull ; 73(2): 416-27, 2013 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-23218873

RESUMO

A mesocosm experiment was conducted to quantify the relationships between the presence and body size of two burrowing heart urchins (Brissopsis lyrifera and Echinocardium cordatum) and rates of sediment nutrient flux. Furthermore, the impact of seawater acidification on these relationships was determined during this 40-day exposure experiment. Using carbon dioxide (CO2) gas, seawater was acidified to pHNBS 7.6, 7.2 or 6.8. Control treatments were maintained in natural seawater (pH≈8.0). Under normocapnic conditions, burrowing urchins were seen to reduce the sediment uptake of nitrite or nitrate whilst enhancing the release of silicate and phosphate. In acidified (hypercapnic) treatments, the biological control of biogeochemical cycles by urchins was significantly affected, probably through the combined impacts of high CO2 on nitrifying bacteria, benthic algae and urchin behaviour. This study highlights the importance of considering biological interactions when predicting the consequences of seawater acidification on ecosystem function.


Assuntos
Dióxido de Carbono/toxicidade , Ecossistema , Ouriços-do-Mar/fisiologia , Poluentes Químicos da Água/toxicidade , Animais , Dióxido de Carbono/análise , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Nitratos/análise , Fosfatos/análise , Água do Mar/química , Poluentes Químicos da Água/análise
7.
Mar Pollut Bull ; 73(2): 435-42, 2013 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-23219529

RESUMO

Whilst the biological consequences of long-term, gradual changes in acidity associated with the oceanic uptake of atmospheric carbon dioxide (CO2) are increasingly studied, the potential effects of rapid acidification associated with a failure of sub-seabed carbon storage infrastructure have received less attention. This study investigates the effects of severe short-term (8days) exposure to acidified seawater on infaunal mediation of ecosystem processes (bioirrigation and sediment particle redistribution) and functioning (nutrient concentrations). Following acidification, individuals of Amphiura filiformis exhibited emergent behaviour typical of a stress response, which resulted in altered bioturbation, but limited changes in nutrient cycling. Under acidified conditions, A. filiformis moved to shallower depths within the sediment and the variability in occupancy depth reduced considerably. This study indicated that rapid acidification events may not be lethal to benthic invertebrates, but may result in behavioural changes that could have longer-term implications for species survival, ecosystem structure and functioning.


Assuntos
Dióxido de Carbono/toxicidade , Ecossistema , Invertebrados/fisiologia , Água do Mar/química , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos/fisiologia , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Oceanos e Mares
8.
Nat Mater ; 11(6): 536-43, 2012 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-22504534

RESUMO

Molecular orientation critically influences the mechanical, chemical, optical and electronic properties of organic materials. So far, molecular-scale ordering in soft matter could be characterized with X-ray or electron microscopy techniques only if the sample exhibited sufficient crystallinity. Here, we show that the resonant scattering of polarized soft X-rays (P-SoXS) by molecular orbitals is not limited by crystallinity and that it can be used to probe molecular orientation down to size scales of 10 nm. We first apply the technique on highly crystalline small-molecule thin films and subsequently use its high sensitivity to probe the impact of liquid-crystalline ordering on charge mobility in polymeric transistors. P-SoXS also reveals scattering anisotropy in amorphous domains of all-polymer organic solar cells where interfacial interactions pattern orientational alignment in the matrix phase, which probably plays an important role in the photophysics. The energy and q-dependence of the scattering anisotropy allows the identification of the composition and the degree of orientational order in the domains.

9.
Vet Comp Oncol ; 10(3): 194-205, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22236194

RESUMO

The purpose of this study was to provide an initial assessment of the potential biologic activity of toceranib phosphate (Palladia®, Pfizer Animal Health, Madison, NJ, USA) in select solid tumours in dogs. Cases in which toceranib was used to treat dogs with apocrine gland anal sac adenocarcinoma (AGASACA), metastatic osteosarcoma (OSA), thyroid carcinoma, head and neck carcinoma and nasal carcinoma were included. Clinical benefit (CB) was observed in 63/85 (74%) dogs including 28/32 AGASACA [8 partial response (PR), 20 stable disease (SD)], 11/23 OSAs (1 PR and 10 SD), 12/15 thyroid carcinomas (4 PR and 8 SD), 7/8 head and neck carcinomas [1 complete response (CR), 5 PR and 1 SD] and 5/7 (1 CR and 4 SD) nasal carcinomas. For dogs experiencing CB, the median dose of toceranib was 2.8 mg kg(-1) , 36/63 (58.7%) were dosed on a Monday/Wednesday/Friday basis and 47/63 (74.6%) were treated 4 months or longer. Although these data provide preliminary evidence that toceranib exhibits CB in dogs with certain solid tumours, future prospective studies are necessary to define its true activity.


Assuntos
Antineoplásicos/uso terapêutico , Doenças do Cão/tratamento farmacológico , Indóis/uso terapêutico , Neoplasias/veterinária , Pirróis/uso terapêutico , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/veterinária , Neoplasias das Glândulas Anais/tratamento farmacológico , Sacos Anais , Animais , Glândulas Apócrinas , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/veterinária , Carcinoma/tratamento farmacológico , Carcinoma/veterinária , Cães , Feminino , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/veterinária , Indóis/farmacologia , Masculino , Neoplasias/tratamento farmacológico , Neoplasias Nasais/tratamento farmacológico , Neoplasias Nasais/veterinária , Osteossarcoma/tratamento farmacológico , Osteossarcoma/veterinária , Pirróis/farmacologia , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/veterinária , Neoplasias da Glândula Tireoide/tratamento farmacológico , Neoplasias da Glândula Tireoide/veterinária
10.
J Vet Intern Med ; 23(1): 123-9, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19175730

RESUMO

BACKGROUND: Feline mammary carcinomas (FMC) are locally invasive and highly metastatic tumors. Because of the high metastatic potential, patients often are treated with adjuvant doxorubicin-based chemotherapy, but little data exist to evaluate the effect of this strategy. HYPOTHESIS: Adjuvant doxorubicin-based chemotherapy improves outcome for FMC compared with surgery alone. ANIMALS: Cats with naturally occurring, biopsy-confirmed FMC treated with either surgery alone (Sx) or with surgery plus adjuvant doxorubicin-based chemotherapy (Sx + Chemo). METHODS: Retrospective cohort study. Clinical data were collected and compared to identify differences between groups. Outcome results were determined and compared. Prognostic factors for disease-free survival (DFS) and overall survival were evaluated. RESULTS: Seventy-three cats were evaluated, of which 37 were in the Sx group and 36 in the Sx + Chemo group. No differences in clinical data were found between Sx and Sx + Chemo groups. Median DFS times for the Sx and Sx + Chemo groups were 372 and 676 days, respectively (P= .15) and median survival times (ST) were 1,406 and 848 days, respectively (P= .78). For cats that underwent a unilateral radical mastectomy, ST was significantly longer for the Sx + Chemo compared with the Sx group (1,998 versus 414 days, respectively; P= .03). CONCLUSIONS AND CLINICAL IMPORTANCE: This study did not find a benefit to adjuvant doxorubicin-based chemotherapy in cats with FMC. Additional studies are required to determine whether patient subgroups with negative prognostic factors may benefit from adjuvant chemotherapy.


Assuntos
Antineoplásicos/administração & dosagem , Antineoplásicos/uso terapêutico , Doenças do Gato/tratamento farmacológico , Doxorrubicina/administração & dosagem , Doxorrubicina/uso terapêutico , Neoplasias Mamárias Animais/tratamento farmacológico , Animais , Doenças do Gato/cirurgia , Gatos , Quimioterapia Adjuvante , Estudos de Coortes , Ciclofosfamida/administração & dosagem , Ciclofosfamida/uso terapêutico , Feminino , Masculino , Neoplasias Mamárias Animais/cirurgia , Estudos Retrospectivos
11.
Nano Lett ; 8(5): 1393-8, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18363343

RESUMO

We develop a simple model that can explain the current-voltage ( J- V) curves of excitonic photovoltaic solar cells, spanning polymer:polymer, polymer:fullerene, and polymer:nanocrystal devices. We show that by subtracting out the dark current, we can explain apparent intensity-dependent characteristics and thus identify geminate recombination as the dominant loss mechanism and establish its electric field dependence. We present an analytic fit to the J- V curves of all measured devices based on a single fitted parameter, the electric field required to split 50% of geminate charge pairs, which we term the critical field. Devices of different material combinations and morphologies can all be described by this method and yield critical fields varying between >1 x 10(8) V/m for blends of poly(9,9'-dioctylfluorene- co-bis- N, N'-(4-butylphenyl)-bis- N, N'-phenyl-1,4-phenylenediamine) (PFB) and poly(9,9'-dioctylfluorene- co-benzothiadiazole) (F8BT) and 8 x 10 (5) V/m for slow-grown blends of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). A comparison with material properties reveals that the primary route to improved photovoltaic materials is enhanced charge delocalization.


Assuntos
Fontes de Energia Elétrica , Eletroquímica/instrumentação , Fulerenos/química , Modelos Teóricos , Fotoquímica/instrumentação , Simulação por Computador , Condutividade Elétrica , Eletroquímica/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Fulerenos/efeitos da radiação , Luz , Fotoquímica/métodos , Polímeros/química , Polímeros/efeitos da radiação , Doses de Radiação
12.
Nanotechnology ; 19(42): 424015, 2008 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-21832675

RESUMO

We investigate the influence of annealing on the morphology of intimately mixed blends of the conjugated polymers poly(9,9'-dioctylfluorene-co-bis-N,N'-(4-butylphenyl)-bis-N,N'-phenyl-1,4-phenylene-diamine) (PFB) and poly(9,9'-dioctylfluorene-co-benzothiadiazole) (F8BT) with scanning transmission x-ray microscopy (STXM). Through the use of a zone plate with theoretical Rayleigh resolution of 30 nm, we are able to resolve sub-100 nm bulk structure in these films. Surprisingly, for unannealed films spin-coated from chloroform we observe features with an average diameter of 85 nm. The high degree of photoluminescence quenching in these as-spun films (>95%) implies that there is significant intermixing within the 85 nm structures, indicating that a hierarchy of phase separation exists even on the length scale of less than 100 nm. With annealing up to 160 °C, close to the T(g) of the components, there is little change in the feature sizes observed by STXM, although an increase in variation of the composition is observed. With annealing above 160 °C the imaged features begin to evolve in size, increasing to 225 nm in extent, alongside large changes in composition with annealing to 200 °C. Comparing the evolution of morphology imaged by STXM with the change in photoluminescence quenching with annealing, we propose that phase separation first evolves via the evolution of relatively pure phases on the length scale of a few to tens of nanometres within the larger 85 nm structures. Once the length scale of compositional fluctuations exceeds 85 nm (for anneal temperatures above 160 °C) the hierarchy of phase separation is lost and the subsequent morphological evolution is readily imaged by STXM. Applying the results of an exciton diffusion and quenching model, we find good agreement between the size of the domains measured by STXM (above 180 °C) and the results of the model for an exciton diffusion length of 15 nm. The growth in domain size and towards purer structures has also been observed with resonant soft x-ray scattering.

13.
Vet Comp Oncol ; 5(2): 90-8, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19754792

RESUMO

The purpose of this retrospective study was to compare Rottweilers diagnosed with osteosarcoma (OSA) with other breeds to determine whether Rottweilers experienced a more aggressive form of the disease. Two hundred and fifty-eight dogs were evaluated (102 clinical and 156 necropsy cases). In the necropsy population, Rottweilers had a younger mean age at death (7.3 versus 9 years, P = 0.006). There were no significant differences between Rottweilers and other breeds in age at diagnosis, median disease-free interval or survival time. However, Rottweilers were more likely to have metastasis to the brain (7 versus 0%, P = 0.03). These results suggest that OSA in Rottweilers may have a different biological behaviour, but this study did not confirm that these differences were associated with a worse outcome.

14.
J Comp Pathol ; 134(2-3): 202-10, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16615935

RESUMO

Tissue transglutaminase II (TGase II) is a dual function protein with both transamidating and guanidine triphosphate (GTP)-binding capabilities. Previous studies have implicated TGase as a pro-apoptotic molecule; however, our recent findings indicate that TGase II may act as a survival factor in various cell types. The purpose of this study was to survey TGase II expression in normal tissue and spontaneous tumours of dogs and cats, by Western blotting and immunohistochemistry. Bladder, liver and adrenal gland exhibited prominent expression of TGase II while other tissues, including mammary gland, displayed limited expression and activity. TGase II GTP-binding in normal tissues was proportional to the level of expression in all tissues examined. Normal mammary tissue and that showing benign hyperplasia did not express TGase II. However, 11/25 (44%) of canine mammary carcinomas and 10/12 (83%) of feline mammary carcinomas strongly expressed TGase II in either a stromal, cellular or combined pattern. The pattern of expression was not related to the classification of mammary carcinoma (solid, tubulopapillary, complex or anaplastic), except that two anaplastic canine mammary carcinomas showed prominent TGase II expression. Two canine mammary carcinoma cell lines showed prominent TGase expression, and when the TGase activity was inhibited, the cells became more sensitive to doxorubicin-induced cell death. Thus, TGase II was significantly expressed in mammary cancers from dogs and cats and immunoreactivity of TGase II was similar to that reported in humans beings. The pro-survival effect of TGase II in canine mammary carcinoma cell lines was similar to that previously reported in humans patients.


Assuntos
Carcinoma/veterinária , Proteínas de Ligação ao GTP/metabolismo , Glândulas Mamárias Animais/enzimologia , Neoplasias Mamárias Animais/enzimologia , Transglutaminases/metabolismo , Animais , Antineoplásicos/farmacologia , Western Blotting/veterinária , Carcinoma/tratamento farmacológico , Carcinoma/enzimologia , Carcinoma/patologia , Gatos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cães , Doxorrubicina/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais/veterinária , Feminino , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Hiperplasia/enzimologia , Hiperplasia/patologia , Hiperplasia/veterinária , Glândulas Mamárias Animais/patologia , Neoplasias Mamárias Animais/tratamento farmacológico , Neoplasias Mamárias Animais/patologia , Proteína 2 Glutamina gama-Glutamiltransferase , Estudos Retrospectivos
15.
Am J Orthod Dentofacial Orthop ; 120(4): 392-7, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11606964

RESUMO

The purpose of this study was to compare the rates of fluoride release with time from 1 nonfluoridated and 3 fluoride-containing orthodontic bonding materials in distilled water and artificial saliva. Materials tested were Assure (Reliance Orthodontic Products, Itasca, Ill), Fuji Ortho LC (GC, Tokyo, Japan), Python (TP Orthodontics, LaPorte, Ind), and Transbond XT (3M Dental Products, Monrovia, Calif). Ten specimens of each material type were stored in distilled water, and 10 of each type were stored in artificial saliva at 37 degrees C. Fluoride release was measured with an ion-specific electrode. Readings were taken periodically for a total time period of 6 months. At day 1, Assure released the most fluoride into distilled water (66.2 microg/cm(2)) and into artificial saliva (65.8 microg/cm(2)), followed by Fuji Ortho LC (25.9 microg/cm(2); 18.8 microg/cm(2)), Python (6.3 microg/cm(2); 4.2 microg/cm(2)), and Transbond (0.1 microg/cm(2); 0.1 microg/cm(2)). The fluoride release rates were highest during the first days of testing, declining to lower but more stable levels. At the end of 6 months, Fuji Ortho LC released the most fluoride (3.8 microg/cm(2); 3.5 microg/cm(2)) followed by Assure (3.1 microg/cm(2); 2.8 microg/cm(2)), Python (2.6 microg/cm(2); 1.7 microg/cm(2)), and Transbond (0.1 microg/cm(2); 0.1 microg/cm(2)). The type of storage medium did not dramatically affect fluoride release. The second part of the study, undertaken after a year of sample storage, tested the 20 samples of Assure for a further 2-week period, after exposure to running and still distilled water. Although fluoride release rates declined with time, they were still higher than the 1.5 microg/cm(2) level that is referenced as inhibiting decalcification of enamel in a clinical environment. Release rates were similar in running and still water at all time points. Throughout the 6-month period, all 3 fluoride-containing materials had rates of fluoride release that could theoretically inhibit decalcification of enamel.


Assuntos
Cariostáticos/química , Colagem Dentária , Cimentos Dentários/química , Fluoretos/química , Resinas Acrílicas/química , Silicatos de Alumínio/química , Análise de Variância , Bis-Fenol A-Glicidil Metacrilato/química , Compômeros/química , Cimentos de Ionômeros de Vidro/química , Luz , Teste de Materiais , Aparelhos Ortodônticos , Cimentos de Resina/química , Saliva Artificial/química , Estatísticas não Paramétricas , Fatores de Tempo , Água/química
16.
J Chromatogr B Biomed Sci Appl ; 746(2): 325-9, 2000 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-11076087

RESUMO

Remacemide hydrochloride, a novel anticonvulsant agent, and its major active metabolite, desglycinylremacemide, were measured simultaneously in brain tissue by high-performance liquid chromatography with UV detection. Intra- and inter-assay variations for remacemide (1, 5, 10 microg/ml) were 5.1, 10.5 and 3.1% and 3.1, 4.0 and 1.3%, respectively. Intra- and inter-assay variations for desglycinylremacemide (1, 5, 10 microg/ml) were 4.2, 3.8 and 8.4% and 7.9, 8.8 and 3.1%, respectively. Limits of detection and quantification for both analytes were 4 and 31 ng/ml, respectively, with recovery consistently > or =85%. This reliable assay has applications in the pre-clinical neuropharmacokinetic and neuropharmacodynamic investigation of remacemide hydrochloride.


Assuntos
Acetamidas/metabolismo , Encéfalo/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Fenetilaminas/metabolismo , Animais , Masculino , Camundongos , Camundongos Endogâmicos ICR , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrofotometria Ultravioleta
17.
J Calif Dent Assoc ; 28(10): 748-58, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11326518

RESUMO

Dental occlusion is much more than the physical contact of the biting surfaces of opposing teeth or their replacements. Occlusion is more comprehensively defined biologically as the coordinated functional interaction between the various cell populations forming the masticatory system as they differentiate, model, remodel, fail, and repair. Morphologic variations are very common and represent the norm. Even though the occlusal or musculoskeletal relationship may not meet the definition of the clinician's concept of an optimum or ideal occlusion, it must be appreciated that for that particular patient, the tissues of the masticatory system may have developed a stable, functional, healthy, and comfortable equilibrium. However, when the functional equilibrium is perturbed or when the occlusion is being re-established, specific treatment criteria are as important today, if not more important with the rapid growth of implant placements, as ever before. Treatment of the occlusion should be considered on an individual basis based on the specific physiologic needs of the various tissue systems within the masticatory system rather than on a preconceived, stereotyped or universal basis. It has long been established and recently proven that proper management of the occlusion is directly correlated to the successful treatment and maintenance of the teeth and, at times, the supporting tissues. On the other hand, it has not, to date, been scientifically proven that occlusion is directly correlated to the musculoskeletal disorders that affect the jaw (temporomandibular joint or masticatory muscle disorders).


Assuntos
Oclusão Dentária , Sistema Estomatognático/fisiologia , Relação Central , Oclusão Dentária Balanceada , Oclusão Dentária Central , Humanos , Arcada Osseodentária/anatomia & histologia , Arcada Osseodentária/fisiologia , Registro da Relação Maxilomandibular , Má Oclusão/complicações , Má Oclusão/terapia , Músculos da Mastigação/anatomia & histologia , Músculos da Mastigação/fisiologia , Planejamento de Assistência ao Paciente , Sistema Estomatognático/anatomia & histologia , Articulação Temporomandibular/anatomia & histologia , Articulação Temporomandibular/fisiologia , Dente/anatomia & histologia , Dente/fisiologia , Resultado do Tratamento
18.
Am J Orthod Dentofacial Orthop ; 116(4): 430-1, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10511671

RESUMO

This article was prepared by the above authors and submitted to members of the TMD academic community for their endorsement. A total of 120 people signed an endorsement; their names are available on request.


Assuntos
Transtornos da Articulação Temporomandibular/diagnóstico , Protocolos Clínicos , Pesquisa em Odontologia , Diagnóstico Diferencial , Medicina Baseada em Evidências , Humanos , Ciência , Transtornos da Articulação Temporomandibular/terapia
19.
20.
ASDC J Dent Child ; 65(6): 449-58, 438, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9883319

RESUMO

The purpose of the present study was to compare bruxing patterns in children with chewing and maximum intercuspal clenching as defined in a clinical and laboratory environment. Six non-bruxing controls and six children who actively bruxed according to parent reports were evaluated. Both control and experimental subjects were assessed by an initial questionnaire, intraoral examination, extraoral examination, dental study models, incisor mandibular tracking, and bilateral surface electromyographic recordings (e.g., EMG). Bruxing was defined as grinding, clenching, or both in combination. The clinical examination consisted of an intraoral examination of the dentition, number of occlusal contacts, and wear facets. Dental study models were used to substantiate the intraoral findings for occlusal contact and wear facets. The mandibular incisors position was tracked during opening, closing, laterotrusion, protrusion, and chewing and compared to the bruxing movements in the experimental subjects. Bilateral surface EMG signals from the temporalis and masseter muscles were recorded in three maximum intercuspal clenches, ten chewing cycles on sugarless gum, and during simulated bruxing. The dental contacts were equal in number bilaterally in both control and bruxing subjects. Both groups demonstrated wear facets, but the bruxing subjects had more facets. The wear facets indicated lateral excursions but not clenching. Only the incisor jaw tracking and bilateral EMG differentiated the bruxing patterns. In those subjects (n = 4) who clenched during bruxing, the EMG pattern was not similar to that of intercuspal clenching and demonstrated its own unique muscle recruitment for the temporalis and masseter muscles. In the subjects who exhibited lateral excursions for bruxing (n = 2), the pattern of muscle recruitment of the two-closing muscles in terms of amplitude was similar for both the bruxing and chewing gum. Our findings support a concept that bruxing may depend upon factors that modify coactivation of muscle recruitment and do not depend upon occlusal contacts.


Assuntos
Bruxismo/fisiopatologia , Mastigação/fisiologia , Análise de Variância , Bruxismo/complicações , Estudos de Casos e Controles , Criança , Oclusão Dentária Traumática/etiologia , Eletromiografia , Feminino , Humanos , Registro da Relação Maxilomandibular , Masculino , Músculo Masseter/fisiologia , Músculo Masseter/fisiopatologia , Modelos Dentários , Contração Muscular , Recrutamento Neurofisiológico , Inquéritos e Questionários , Músculo Temporal/fisiologia , Músculo Temporal/fisiopatologia , Atrito Dentário/etiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...