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1.
Hydrobiologia ; : 1-21, 2022 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-36065211

RESUMO

Monitoring the condition (water quality, biodiversity, hydromorphology) of small water bodies presents a challenge for the relevant authorities in terms of time and resources (labour and financial) due to the extensive length of the stream network or the sheer number of small standing water bodies. Citizen science can help address information gaps, but the effort required should not be underestimated if such projects are to generate reliable and sustained data collection. The overall aim of this paper is to propose a framework for operationalisation of citizen science targeting collection of data from small water bodies. We first consider the data gaps and the elements (water chemistry, ecology, hydromorphology) to be addressed, in order to define where citizen science could best make an impact. We review examples of tools and methods that are appropriate for small water bodies, based on experience from a selection of freshwater citizen science projects, and the support that is needed for effective and sustained small water body projects across Europe.

2.
J Geophys Res Solid Earth ; 127(4): e2021JB023897, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35865712

RESUMO

Aseismic afterslip is postseismic fault sliding that may significantly redistribute crustal stresses and drive aftershock sequences. Afterslip is typically modeled through geodetic observations of surface deformation on a case-by-case basis, thus questions of how and why the afterslip moment varies between earthquakes remain largely unaddressed. We compile 148 afterslip studies following 53 M w 6.0-9.1 earthquakes, and formally analyze a subset of 88 well-constrained kinematic models. Afterslip and coseismic moments scale near-linearly, with a median Spearman's rank correlation coefficient (CC) of 0.91 after bootstrapping (95% range: 0.89-0.93). We infer that afterslip area and average slip scale with coseismic moment as M o 2 / 3 and M o 1 / 3 , respectively. The ratio of afterslip to coseismic moment (M rel ) varies from <1% to >300% (interquartile range: 9%-32%). M rel weakly correlates with M o (CC: -0.21, attributed to a publication bias), rupture aspect ratio (CC: -0.31), and fault slip rate (CC: 0.26, treated as a proxy for fault maturity), indicating that these factors affect afterslip. M rel does not correlate with mainshock dip, rake, or depth. Given the power-law decay of afterslip, we expected studies that started earlier and spanned longer timescales to capture more afterslip, but M rel does not correlate with observation start time or duration. Because M rel estimates for a single earthquake can vary by an order of magnitude, we propose that modeling uncertainty currently presents a challenge for systematic afterslip analysis. Standardizing modeling practices may improve model comparability, and eventually allow for predictive afterslip models that account for mainshock and fault zone factors to be incorporated into aftershock hazard models.

3.
Mar Pollut Bull ; 170: 112664, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34217051

RESUMO

Increasing the precision of nitrogen (N) fertiliser management in cropping systems is integral to increasing the environmental and economic sustainability of cropping. In a simulation study, we found that natural variability in year-to-year climate had a major effect on optimum N fertiliser rates for sugarcane in the Tully region of north-eastern Australia, where N discharges pose high risks to Great Barrier Reef ecosystems. There were interactions between climate and other factors affecting crop growth that made optimum N rates field-specific. The regional average optimum N fertiliser rate was substantially lower than current industry guidelines. Likewise, simulated N losses to the environment at optimum N fertiliser rates were substantially lower than the simulated losses at current industry fertiliser guidelines. Dissolved N discharged from rivers is related to fertiliser applications. If the reductions in N applications identified in the study occurred in the Tully region, the reduction in dissolved N discharges from rivers in the region would almost meet current water quality improvement targets. Whilst there were many assumptions made in this exploratory study, and there are many steps between the study and a practically implemented dynamic N fertiliser recommendation system, the potential environmental benefits justify field validation and further development of the concepts identified in the study.


Assuntos
Fertilizantes , Nitrogênio , Agricultura , Clima , Ecossistema , Fertilizantes/análise
4.
Celest Mech Dyn Astron ; 130(2): 12, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-33184531

RESUMO

This paper presents rich new families of relative orbits for spacecraft formation flight generated through the application of continuous thrust with only minimal intervention into the dynamics of the problem. Such simplicity facilitates implementation for small, low-cost spacecraft with only position state feedback, and yet permits interesting and novel relative orbits in both two- and three-body systems with potential future applications in space-based interferometry, hyperspectral sensing, and on-orbit inspection. Position feedback is used to modify the natural frequencies of the linearised relative dynamics through direct manipulation of the system eigenvalues, producing new families of stable relative orbits. Specifically, in the Hill-Clohessy-Wiltshire frame, simple adaptations of the linearised dynamics are used to produce a circular relative orbit, frequency-modulated out-of-plane motion, and a novel doubly periodic cylindrical relative trajectory for the purposes of on-orbit inspection. Within the circular restricted three-body problem, a similar minimal approach with position feedback is used to generate new families of stable, frequency-modulated relative orbits in the vicinity of a Lagrange point, culminating in the derivation of the gain requirements for synchronisation of the in-plane and out-of-plane frequencies to yield a singly periodic tilted elliptical relative orbit with potential use as a Lunar far-side communications relay. The Δ v requirements for the cylindrical relative orbit and singly periodic Lagrange point orbit are analysed, and it is shown that these requirements are modest and feasible for existing low-thrust propulsion technology.

5.
BJOG ; 123(4): 588-97, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26542419

RESUMO

OBJECTIVE: To assess whether antenatal exercise in overweight/obese women would improve maternal and perinatal outcomes. DESIGN: Two-arm parallel randomised controlled trial. SETTING: Home-based intervention in Auckland, New Zealand. POPULATION AND SAMPLE: Pregnant women with body mass index ≥25 kg/m(2) . METHODS: Participants were randomised to a 16-week moderate-intensity stationary cycling programme from 20 weeks of gestation, or to a control group with no exercise intervention. MAIN OUTCOME MEASURES: Primary outcome was offspring birthweight. Perinatal and maternal outcomes were assessed, with the latter including weight gain, aerobic fitness, quality of life, pregnancy outcomes, and postnatal body composition. Exercise compliance was recorded with heart rate monitors. RESULTS: Seventy-five participants were randomised in the study (intervention 38, control 37). Offspring birthweight (adjusted mean difference 104 g; P = 0.35) and perinatal outcomes were similar between groups. Aerobic fitness improved in the intervention group compared with controls (48.0-second improvement in test time to target heart rate; P = 0.019). There was no difference in weight gain, quality of life, pregnancy outcomes or postnatal maternal body composition between groups. However, compliance with exercise protocol was poor, with an average of 33% of exercise sessions completed. Sensitivity analyses showed that greater compliance was associated with improved fitness (increased test time (P = 0.002), greater VO2 peak (P = 0.015), and lower resting heart rate (P = 0.014)), reduced postnatal adiposity (reduced fat mass (P = 0.007) and body mass index (P = 0.035)) and better physical quality of life (P = 0.034). CONCLUSIONS: Maternal non-weight-bearing moderate-intensity exercise in pregnancy improved fitness but did not affect birthweight or clinical outcomes. TWEETABLE ABSTRACT: Moderate-intensity exercise in overweight/obese pregnant women improved fitness but had no clinical effects.


Assuntos
Terapia por Exercício , Obesidade/terapia , Sobrepeso/terapia , Gestantes , Cuidado Pré-Natal , Adulto , Índice de Massa Corporal , Feminino , Humanos , Nova Zelândia/epidemiologia , Obesidade/epidemiologia , Obesidade/prevenção & controle , Sobrepeso/epidemiologia , Sobrepeso/prevenção & controle , Cooperação do Paciente , Gravidez , Resultado da Gravidez , Gestantes/psicologia , Qualidade de Vida , Comportamento de Redução do Risco , Resultado do Tratamento , Aumento de Peso
6.
Nat Commun ; 5: 3471, 2014 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-24699342

RESUMO

A key challenge for volcanological science and hazard management is that few of the world's volcanoes are effectively monitored. Satellite imagery covers volcanoes globally throughout their eruptive cycles, independent of ground-based monitoring, providing a multidecadal archive suitable for probabilistic analysis linking deformation with eruption. Here we show that, of the 198 volcanoes systematically observed for the past 18 years, 54 deformed, of which 25 also erupted. For assessing eruption potential, this high proportion of deforming volcanoes that also erupted (46%), together with the proportion of non-deforming volcanoes that did not erupt (94%), jointly represent indicators with 'strong' evidential worth. Using a larger catalogue of 540 volcanoes observed for 3 years, we demonstrate how this eruption-deformation relationship is influenced by tectonic, petrological and volcanic factors. Satellite technology is rapidly evolving and routine monitoring of the deformation status of all volcanoes from space is anticipated, meaning probabilistic approaches will increasingly inform hazard decisions and strategic development.

8.
Science ; 335(6074): 1310-1, 2012 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-22422969
9.
Environ Pollut ; 157(6): 1841-8, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19232800

RESUMO

To detect effects of pesticides on non-target freshwater organisms the Species at risk (SPEAR(pesticides)) bioindicator based on biological traits was previously developed and successfully validated over different biogeographical regions of Europe using species-level data on stream invertebrates. Since many freshwater biomonitoring programmes have family-level taxonomic resolution we tested the applicability of SPEAR(pesticides) with family-level biomonitoring data to indicate pesticide effects in streams (i.e. insecticide toxicity of pesticides). The study showed that the explanatory power of the family-level SPEAR(fm)(pesticides) is not significantly lower than the species-level index. The results suggest that the family-level SPEAR(fm)(pesticides) is a sensitive, cost-effective, and potentially European-wide bioindicator of pesticide contamination in flowing waters. Class boundaries for SPEAR(pesticides) according to EU Water Framework Directive are defined to contribute to the assessment of ecological status of water bodies.


Assuntos
Ecotoxicologia/métodos , Invertebrados/efeitos dos fármacos , Modelos Teóricos , Praguicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Ecossistema , Exposição Ambiental , Monitoramento Ambiental/métodos , Europa (Continente) , Invertebrados/fisiologia , Praguicidas/análise , Rios , Especificidade da Espécie , Poluentes Químicos da Água/análise
10.
Lupus ; 18(1): 61-6, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19074170

RESUMO

The p53 tumour suppressor is the central regulator of apoptosis. Previously, the functional TP53 Arg72Pro polymorphism was found to be associated with systemic lupus erythematosus (SLE) in Koreans but not Spaniards. MDM2 is the major negative regulator of p53. An intronic polymorphism in MDM2, the SNP309, attenuates p53 activity and is associated with accelerated tumour development in premenopausal women. Polymorphic variation in MDM2 has never been studied in SLE. The aim of this study is to further assess the contribution of p53-pathway genetic variation to SLE by testing the association of the TP53 Arg72Pro polymorphism and the MDM2 SNP309 with SLE in a well-characterised and ethnically diverse cohort of patients with both childhood- and adult-onset SLE (n = 314). No association was found between the TP53 Arg72Pro polymorphism and SLE in patients of European descent, Asian descent or in African Americans, nor was an association found between the MDM2 SNP309 and SLE in patients of European descent or in African Americans. In addition, there was no correlation between either variant and early-onset disease or nephritis, an index of severe disease. It is concluded that neither the TP53 Arg72Pro polymorphism nor the MDM2 SNP309 contributes significantly to either susceptibility or disease severity in SLE.


Assuntos
Predisposição Genética para Doença , Lúpus Eritematoso Sistêmico/etnologia , Lúpus Eritematoso Sistêmico/genética , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteína Supressora de Tumor p53/genética , Adolescente , Adulto , Negro ou Afro-Americano/genética , Idade de Início , Povo Asiático/genética , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Lactente , Nefrite Lúpica/genética , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Índice de Gravidade de Doença , População Branca/genética , Adulto Jovem
11.
Leuk Res ; 26(1): 111-5, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11734309

RESUMO

Long-term survival of chronic myeloid leukaemia (CML) patients transplanted in chronic phase with a replete marrow have been described previously. The same success has not been achieved with patients in more advanced stages of the disease. We describe a CML patient who received an allogeneic bone marrow transplantation in accelerated phase. Cytogenetic and molecular analysis confirmed donor chimaerism, and the absence of the BCR-ABL mRNA. Almost 12 years post-transplant relapse was noted. Cytogenetic analyses showed a complex evolving karyotype. These findings are correlated with the longitudinal molecular analysis utilising real-time and VNTR PCR.


Assuntos
Transplante de Medula Óssea/efeitos adversos , Leucemia Mielogênica Crônica BCR-ABL Positiva/etiologia , Quimeras de Transplante/genética , Adolescente , Evolução Fatal , Proteínas de Fusão bcr-abl/genética , Efeito Enxerto vs Tumor , Humanos , Cariotipagem , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/terapia , Masculino , Recidiva Local de Neoplasia , RNA Mensageiro/análise , RNA Neoplásico/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo , Transplante Homólogo
12.
Eur J Pharmacol ; 431(3): 305-10, 2001 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-11730722

RESUMO

Recent data indicate that (2S,4R)-4-methylglutamate is a selective agonist for low affinity (GluR5 and GluR6) kainate receptor subunits. In the present study, we have employed [(3)H](2S,4R)-4-methylglutamate to examine low affinity kainate receptor distribution in mouse brain. [(3)H](2S,4R)-4-Methylglutamate labelled a single site in murine cerebrocortical membranes (K(d)=9.9+/-2.7 nM, B(max)=296.3+/-27.1 fmol mg protein(-1)). The binding of 8 nM [(3)H](2S,4R)-4-methylglutamate was displaced by several non-NMDA receptor ligands (K(i)+/-S.E.M.): domoate (1.1+/-0.2 nM)>kainate (7.1+/-1.1 nM) >> L-glutamate (187.6+/-31.9 nM) >> (S)-alpha-amino-3-hydroxy-5-methyl-4-isoazolepropionic acid (AMPA) (>50 microM). [(3)H](2S,4R)-4-Methylglutamate autoradiography revealed a widespread regional distribution of low affinity kainate receptors. Highest binding densities occurred within deep layers of the cerebral cortex, olfactory bulb, basolateral amygdala and hippocampal CA3 subregion. Moderate labelling was also evident in the nucleus accumbens, dentate gyrus, caudate putamen, hypothalamus and cerebellar granule cell layer. These data show that [(3)H](2S,4R)-4-methylglutamate is a useful radioligand for selectively labelling low affinity kainate receptors.


Assuntos
Encéfalo/fisiologia , Glutamatos/análise , Receptores de Ácido Caínico/análise , Animais , Autorradiografia , Sítios de Ligação , Encéfalo/metabolismo , Mapeamento Encefálico , Camundongos , Trítio
13.
J Rheumatol Suppl ; 64: 8-12, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11642509

RESUMO

Trials of high dose immunosuppression and peripheral blood stem cell transplantation (PBSCT) in patients with severe rheumatoid arthritis (RA) have now commenced based on encouraging data from case reports of patients with coexistent malignancy and animal transplant models. Early case reports in Australia documented the potential for cure of RA in most patients receiving allogeneic or syngeneic transplants. However, the relatively high morbidity and mortality of these procedures has necessitated the use of autologous PBSCT. in accordance with international guidelines released by the EBMT/EULAR working party. Phase I trials in autologous PBSCT have seen substantial remissions of RA in the majority of patients who had previously failed all available therapies. Recurrence of disease occurs in most patients usually within 2 years; however, the use of disease modifying agents after recurrence results in substantial amelioration of the disease, again suggesting a form of "immunomodulation." This observation raises the possibility of maintenance therapy associated with procedure to prolong responses. Other modifications of the procedure are discussed, including T cell depletion of the graft, currently the subject of a randomized trial.


Assuntos
Artrite Reumatoide/terapia , Transplante de Células-Tronco Hematopoéticas , Antígenos CD34/imunologia , Artrite Reumatoide/imunologia , Austrália , Ensaios Clínicos como Assunto , Relação Dose-Resposta a Droga , Humanos , Imunossupressores/uso terapêutico , Condicionamento Pré-Transplante
14.
J Immunol ; 167(2): 1112-7, 2001 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-11441123

RESUMO

Nonobese diabetic (NOD) mice develop spontaneous autoimmune diabetes that involves participation of both CD4+ and CD8+ T cells. Previous studies have demonstrated spontaneous reactivity to self-Ags within the CD4+ T cell compartment in this strain. Whether CD8+ T cells in NOD mice achieve and maintain tolerance to self-Ags has not previously been evaluated. To investigate this issue, we have assessed the extent of tolerance to a model pancreatic Ag, the hemagglutinin (HA) molecule of influenza virus, that is transgenically expressed by pancreatic islet beta cells in InsHA mice. Previous studies have demonstrated that BALB/c and B10.D2 mice that express this transgene exhibit tolerance of HA and retain only low-avidity CD8+ T cells specific for the dominant peptide epitope of HA. In this study, we present data that demonstrate a deficiency in peripheral tolerance within the CD8+ T cell repertoire of NOD-InsHA mice. CD8+ T cells can be obtained from NOD-InsHA mice that exhibit high avidity for HA, as measured by tetramer (K(d)HA) binding and dose titration analysis. Significantly, these autoreactive CD8+ T cells can cause diabetes very rapidly upon adoptive transfer into NOD-InsHA recipient mice. The data presented demonstrate a retention in the repertoire of CD8+ T cells with high avidity for islet Ags that could contribute to autoimmune diabetes in NOD mice.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Tolerância Imunológica , Camundongos Endogâmicos NOD/imunologia , Transferência Adotiva , Animais , Autoantígenos/metabolismo , Linfócitos T CD8-Positivos/virologia , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/imunologia , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Tolerância Imunológica/genética , Vírus da Influenza A/imunologia , Ativação Linfocitária/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos NOD/genética , Camundongos Transgênicos , Ligação Proteica/genética , Ligação Proteica/imunologia , Quimera por Radiação/imunologia , Linfócitos T Citotóxicos/transplante
15.
Int Immunol ; 13(8): 1085-93, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11470778

RESUMO

To further define the molecular basis of tolerance to a peripherally expressed antigen we have correlated differences in functional capacity with biochemical events in hemagglutinin (HA)-specific cytotoxic T lymphocyte (CTL) clones derived either from a conventional B10.D2 mouse that is not tolerant to HA (D2 Clone 6) or from an InsHA mouse that is tolerant to HA (InsHA Clone 12). D2 Clone 6, but not InsHA Clone 12, triggers diabetes following in vivo transfer into irradiated InsHA hosts. This diabetogenic clone shows complete and sustained phosphorylation of TCR zeta chain and ZAP-70 following stimulation with HA-pulsed antigen-presenting cells. In contrast, InsHA Clone 12 showed only partial phosphorylation of TCR zeta and no phosphorylation of ZAP-70. There was no defect in activation or recruitment of Lck to the TCR complex in both the clones following stimulation with the cognate antigen. This deficiency in the proximal signaling in the InsHA Clone 12 could be overcome by increasing the strength of signal through the CD3-TCR complex, indicating that the signaling machinery of InsHA Clone 12 was functional. These data demonstrate that the HA-responsive CD8(+) T cells that can be retrieved from InsHA mice after tolerance induction respond to HA as a partial agonist/antagonist.


Assuntos
Citotoxicidade Imunológica , Tolerância Imunológica , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/metabolismo , Animais , Células Clonais , Diabetes Mellitus Experimental/imunologia , Imunofenotipagem , Ligantes , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fosforilação , Proteínas Tirosina Quinases/metabolismo , Transdução de Sinais/imunologia , Linfócitos T Citotóxicos/enzimologia , Proteína-Tirosina Quinase ZAP-70
16.
Physiol Meas ; 22(2): 365-76, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11411246

RESUMO

Single frequency bioelectrical impedance analysis is an inexpensive, quick and painless means of estimating body composition. However, current approaches to estimating body composition from segment resistivity have some drawbacks. The purpose of this study was to overcome these limitations by developing a better model of the relationship between resistivity and body composition. A three-compartment model of body mass and body segment resistivity is presented and calibrated to predict %Fat estimated by underwater weighing. The subject population from which the data were obtained was heterogeneous. Both sexes were represented, as were a range of ages (21-44 years), ethnic backgrounds, body masses (47.0-129.0 kg) and body compositions (%Fat = 8.7-50.7%). Based on resistivity measurements from the upper arm and upper leg, and measurements of subject height and weight, the model predicted %Fat with errors comparable to those reported for other methods based on segmental resistivity. All the terms in the calibrated model represented a physical component of the body and show reasonable agreement with resistivity measured in tissue samples. In short, predicting %Fat from resistivity of the proximal arm and leg segments compares favourably with other methods based on segment resistivity.


Assuntos
Tecido Adiposo/fisiologia , Braço/fisiologia , Composição Corporal/fisiologia , Perna (Membro)/fisiologia , Adulto , Algoritmos , Índice de Massa Corporal , Peso Corporal/fisiologia , Calibragem , Densitometria , Impedância Elétrica , Feminino , Humanos , Masculino , Modelos Biológicos
17.
Br J Educ Psychol ; 71(Pt 1): 133-49, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11307705

RESUMO

AIM: To produce a revised two-factor version of the Study Process Questionnaire (R-SPQ-2F) suitable for use by teachers in evaluating the learning approaches of their students. The revised instrument assesses deep and surface approaches only, using fewer items. METHOD: A set of 43 items was drawn up for the initial tests. These were derived from: the original version of the SPQ, modified items from the SPQ, and new items. A process of testing and refinement eventuated in deep and surface motive and strategy scales each with 5 items, 10 items per approach score. The final version was tested using reliability procedures and confirmatory factor analysis. SAMPLE: The sample for the testing and refinement process consisted of 229 students from the health sciences faculty of a university in Hong Kong. A fresh sample of 495 undergraduate students from a variety of departments of the same university was used for the test of the final version. RESULTS: The final version of the questionnaire had acceptable Cronbach alpha values for scale reliability. Confirmatory factor analysis indicated a good fit to the intended two-factor structure. Both deep and surface approach scales had well identified motive and strategy subscales. CONCLUSION: The revision process has resulted in a simple questionnaire which teachers can use to evaluate their own teaching and the learning approaches of their students.


Assuntos
Aprendizagem , Inquéritos e Questionários , Ensino/normas , Análise Fatorial , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes
19.
Proc Natl Acad Sci U S A ; 98(7): 3814-9, 2001 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-11259672

RESUMO

The human brm (hbrm) protein (homologue of the Drosophila melanogaster brahma and Saccharomyces cervisiae SNF-2 proteins) is part of a polypeptide complex believed to regulate chromatin conformation. We have shown that the hbrm protein is cleaved in NB4 leukemic cells after induction of apoptosis by UV-irradiation, DNA damaging agents, or staurosporine. Because hbrm is found only in the nucleus, we have investigated the nature of the proteases that may regulate the degradation of this protein during apoptosis. In an in vitro assay, the hbrm protein could not be cleaved by caspase-3, -7, or -6, the "effector" caspases generally believed to carry out the cleavage of nuclear protein substrates. In contrast, we find that cathepsin G, a granule enzyme found in NB4 cells, cleaves hbrm in a pattern similar to that observed in vivo during apoptosis. In addition, a peptide inhibitor of cathepsin G blocks hbrm cleavage during apoptosis but does not block activation of caspases or cleavage of the nuclear protein polyADP ribose polymerase (PARP). Although localized in granules and in the Golgi complex in untreated cells, cathepsin G becomes diffusely distributed during apoptosis. Cleavage by cathepsin G removes a 20-kDa fragment containing a bromodomain from the carboxyl terminus of hbrm. This cleavage disrupts the association between hbrm and the nuclear matrix; the 160-kDa hbrm cleavage fragment is less tightly associated with the nuclear matrix than full-length hbrm.


Assuntos
Apoptose/fisiologia , Catepsinas/metabolismo , Fatores de Transcrição/metabolismo , Raios Ultravioleta , Animais , Células COS , Catepsina G , Células Epiteliais/metabolismo , Fibroblastos/metabolismo , Células HeLa , Humanos , Serina Endopeptidases
20.
J Okla Dent Assoc ; 92(2): 33-8, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11808071

RESUMO

Ultrasonic instrumentation has added a new horizon to endodontic treatment possibilities. It is a tool in the arsenal of instruments currently used by almost every endodontist in the United States. The use of ultrasonic instrumentation was formerly confined solely to periodontics, but has slowly come to be an indispensable tool in endodontics as well.


Assuntos
Tratamento do Canal Radicular/instrumentação , Terapia por Ultrassom/instrumentação , Cavidade Pulpar/patologia , Desenho de Equipamento/classificação , Corpos Estranhos/terapia , Humanos , Técnica para Retentor Intrarradicular/instrumentação , Pulpectomia/instrumentação , Retratamento , Obturação Retrógrada/instrumentação , Obturação Retrógrada/métodos , Materiais Restauradores do Canal Radicular/química , Tratamento do Canal Radicular/métodos , Propriedades de Superfície , Terapia por Ultrassom/métodos
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