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1.
Nat Ecol Evol ; 7(6): 841-851, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37142743

RESUMO

Alpine river biodiversity around the world is under threat from glacier retreat driven by rapid warming, yet our ability to predict the future distributions of specialist cold-water species is currently limited. Here we link future glacier projections, hydrological routing methods and species distribution models to quantify the changing influence of glaciers on population distributions of 15 alpine river invertebrate species across the entire European Alps, from 2020 to 2100. Glacial influence on rivers is projected to decrease steadily, with river networks expanding into higher elevations at a rate of 1% per decade. Species are projected to undergo upstream distribution shifts where glaciers persist but become functionally extinct where glaciers disappear completely. Several alpine catchments are predicted to offer climate refugia for cold-water specialists. However, present-day protected area networks provide relatively poor coverage of these future refugia, suggesting that alpine conservation strategies must change to accommodate the future effects of global warming.


Assuntos
Camada de Gelo , Rios , Animais , Refúgio de Vida Selvagem , Ecossistema , Biodiversidade , Invertebrados
2.
Science ; 364(6441)2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31097641

RESUMO

The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation. We describe initial results from these encounter observations. MU69 is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU69's origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes.

3.
J Geophys Res Space Phys ; 124(9): 7413-7424, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35860291

RESUMO

Pluto energies of a few kiloelectron volts and suprathermal ions with tens of kiloelectron volts and above. We measure this population using the Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument on board the New Horizons spacecraft that flew by Pluto in 2015. Even though the measured ions have gyroradii larger than the size of Pluto and the cross section of its magnetosphere, we find that the boundary of the magnetosphere is depleting the energetic ion intensities by about an order of magnitude close to Pluto. The intensity is increasing exponentially with distance to Pluto and reaches nominal levels of the interplanetary medium at about 190R P distance. Inside the wake of Pluto, we observe oscillations of the ion intensities with a periodicity of about 0.2 hr. We show that these can be quantitatively explained by the electric field of an ultralow-frequency wave and discuss possible physical drivers for such a field. We find no evidence for the presence of plutogenic ions in the considered energy range.

4.
Hum Vaccin Immunother ; 14(4): 941-946, 2018 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-29252117

RESUMO

Live attenuated influenza vaccines (LAIV) induce CD8+ T lymphocyte responses that play an important role in killing virus-infected cells. Despite the relative conservation of internal influenza A proteins, the epitopes recognized by T cells can undergo drift under immune pressure. The internal proteins of Russian LAIVs are derived from the master donor virus A/Leningrad/134/17/57 (Len/17) isolated 60 years ago and as such, some CD8+ T cell epitopes may vary between the vaccine and circulating wild-type strains. To partially overcome this issue, the nucleoprotein (NP) gene of wild-type virus can be incorporated into LAIV reassortant virus, along with the HA and NA genes. The present study compares the human CD8+ T cell memory responses to H3N2 LAIVs with the Len/17 or the wild-type NP using an in vitro model.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Nucleoproteínas/imunologia , Vacinas Atenuadas/imunologia , Anticorpos Antivirais/imunologia , Linhagem Celular Tumoral , Epitopos de Linfócito T/imunologia , Humanos , Vírus da Influenza A Subtipo H3N2/imunologia , Federação Russa
5.
Mucosal Immunol ; 10(6): 1581-1593, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28327617

RESUMO

Cell surface mucin (cs-mucin) glycoproteins are constitutively expressed at the surface of respiratory epithelia where pathogens such as influenza A virus (IAV) gain entry into cells. Different members of the cs-mucin family each express a large and heavily glycosylated extracellular domain that towers above other receptors on the epithelial cell surface, a transmembrane domain that enables shedding of the extracellular domain, and a cytoplasmic tail capable of triggering signaling cascades. We hypothesized that IAV can interact with the terminal sialic acids presented on the extracellular domain of cs-mucins, resulting in modulation of infection efficiency. Utilizing human lung epithelial cells, we found that IAV associates with the cs-mucin MUC1 but not MUC13 or MUC16. Overexpression of MUC1 by epithelial cells or the addition of sialylated synthetic MUC1 constructs, reduced IAV infection in vitro. In addition, Muc1-/- mice infected with IAV exhibited enhanced morbidity and mortality, as well as greater inflammatory mediator responses compared to wild type mice. This study implicates the cs-mucin MUC1 as a critical and dynamic component of the innate host response that limits the severity of influenza and provides the foundation for exploration of MUC1 in resolving inflammatory disease.


Assuntos
Vírus da Influenza A/imunologia , Influenza Humana/imunologia , Proteínas de Membrana/metabolismo , Mucina-1/metabolismo , Infecções por Orthomyxoviridae/imunologia , Células A549 , Animais , Células CHO , Cricetulus , Progressão da Doença , Feminino , Humanos , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mucina-1/genética , Ácido N-Acetilneuramínico/genética , Domínios Proteicos/genética
6.
Int J Sports Med ; 37(12): 992-996, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27479459

RESUMO

Soccer matches consist of a variety of different activities, including repeated sprints. Time to attain velocity (TTAV), load range (LR) and the torque-angle-velocity relationship (TAV3D) represent an important measurement of muscle performance, however there are few related studies. The aim of this study was to compare these outcomes between soccer players of different age category. 17 professional (PRO) and 17 under-17 (U17) soccer players were assessed for concentric knee flexion/extension at 60, 120 and 300°/s. For the extensor muscles, differences were found in favor of the U17 group for TTAV and LR outcomes at 120°/s, however, the PRO group maintained higher torques in both movement directions in comparison to the U17 in TAV3D evaluation. These results suggest that muscle performance of the PRO group is more efficient than the U17 group.


Assuntos
Articulação do Joelho/fisiologia , Músculo Esquelético/fisiologia , Corrida/fisiologia , Futebol/fisiologia , Adolescente , Adulto , Fatores Etários , Atletas , Desempenho Atlético/fisiologia , Humanos , Fatores de Tempo , Torque , Adulto Jovem
7.
Bull Math Biol ; 78(3): 436-67, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26934886

RESUMO

The earliest cell fate decisions in a developing embryo are those associated with establishing the germ layers. The specification of the mesoderm and endoderm is of particular interest as the mesoderm is induced from the endoderm, potentially from an underlying bipotential group of cells, the mesendoderm. Mesendoderm formation has been well studied in an amphibian model frog, Xenopus laevis, and its formation is driven by a gene regulatory network (GRN) induced by maternal factors deposited in the egg. We have recently demonstrated that the axolotl, a urodele amphibian, utilises a different topology in its GRN to specify the mesendoderm. In this paper, we develop spatially structured mathematical models of the GRNs governing mesendoderm formation in a line of cells. We explore several versions of the model of mesendoderm formation in both Xenopus and the axolotl, incorporating the key differences between these two systems. Model simulations are able to reproduce known experimental data, such as Nodal expression domains in Xenopus, and also make predictions about how the positional information derived from maternal factors may be interpreted to drive cell fate decisions. We find that whilst cell-cell signalling plays a minor role in Xenopus, it is crucial for correct patterning domains in axolotl.


Assuntos
Anfíbios/embriologia , Modelos Biológicos , Ambystoma mexicanum/embriologia , Ambystoma mexicanum/genética , Proteínas de Anfíbios/genética , Anfíbios/genética , Animais , Simulação por Computador , Endoderma/embriologia , Regulação da Expressão Gênica no Desenvolvimento , Redes Reguladoras de Genes , Conceitos Matemáticos , Mesoderma/embriologia , Ligantes da Sinalização Nodal/genética , Xenopus laevis/embriologia , Xenopus laevis/genética
8.
Science ; 351(6279): aad9045, 2016 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-26989259

RESUMO

The New Horizons spacecraft carried three instruments that measured the space environment near Pluto as it flew by on 14 July 2015. The Solar Wind Around Pluto (SWAP) instrument revealed an interaction region confined sunward of Pluto to within about 6 Pluto radii. The region's surprisingly small size is consistent with a reduced atmospheric escape rate, as well as a particularly high solar wind flux. Observations from the Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument suggest that ions are accelerated and/or deflected around Pluto. In the wake of the interaction region, PEPSSI observed suprathermal particle fluxes equal to about 1/10 of the flux in the interplanetary medium and increasing with distance downstream. The Venetia Burney Student Dust Counter, which measures grains with radii larger than 1.4 micrometers, detected one candidate impact in ±5 days around New Horizons' closest approach, indicating an upper limit of <4.6 kilometers(-3) for the dust density in the Pluto system.

9.
Environ Sci Pollut Res Int ; 23(4): 3956-62, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26635223

RESUMO

Pharmaceuticals are now recognised as important pollutants in freshwater systems, but a shortcoming of effects studies is that they have focused on structural endpoints and impacts on ecosystem functioning are poorly understood. The decomposition of organic matter is an important functional process in aquatic systems, and it is known that this can be impacted by the presence of pollutants. Previous studies on leaf litter breakdown have only considered the effects of antibiotics and not other groups of drugs though. The current study investigated the effects of anti-inflammatories, a beta-blocker and an antibiotic on microbially mediated breakdown of leaf litter in the laboratory; colonisation of leaf packs by benthic macroinvertebrates when placed in a stream; and shredding of leaf litter by these organisms. Furthermore, the effects of single compounds relative to their mixture were assessed. It was found that exposure of leaf litter to the study compounds did not influence its breakdown by microbes in the laboratory or macroinvertebrates in a stream. Exposure of leaf litter to pharmaceuticals also had no effect on its colonisation by macroinvertebrates in this study. Many unknowns remain, however, and further studies of the effects of pharmaceuticals on structural and functional endpoints are needed to aid aquatic conservation.


Assuntos
Antagonistas Adrenérgicos beta/farmacologia , Antibacterianos/farmacologia , Anti-Inflamatórios/farmacologia , Biodegradação Ambiental , Folhas de Planta/efeitos dos fármacos , Microbiologia da Água , Poluentes da Água/farmacologia , Animais , Bactérias/efeitos dos fármacos , Ecossistema , Água Doce , Invertebrados/efeitos dos fármacos , Solo
10.
Int J Sports Med ; 35(14): 1179-83, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25254899

RESUMO

It has been demonstrated that body cooling may decrease neuromuscular performance. However, the effect of a single session of whole body cryotherapy (-110°C) on neuromuscular performance has not been well documented. Thus, the aim of this study was to evaluate the effects of a single exposure of WBC on elbow flexor neuromuscular performance. Thirteen physically active, healthy young men (age=27.9±4.2 years, mass=79.4±9.7 kg, height=176.7±5.2 cm) were randomly exposed to 2 different experimental conditions separated by a minimum of 72 h: 1) whole body cryotherapy- 3 min at -110°C; 2) control- 3 min at 21°C. All subjects were tested for maximal isokinetic elbow flexion at 60°.s(-1) 30 min before and 10 min after each condition. There were no significant differences in peak torque, average power, total work or muscle activity between conditions. Peak torque was lower at post-test compared to pre-test in both conditions (F=6.58, p=0.025). However, there were no differences between pre-test and post-test for any other variables. These results indicate that strength specialists, athletic trainers and physical therapists might utilize whole body cryotherapy before training or rehabilitation without compromising neuromuscular performance of the elbow flexors.


Assuntos
Crioterapia/métodos , Cotovelo/fisiologia , Exercício Físico/fisiologia , Músculo Esquelético/fisiologia , Adulto , Eletromiografia , Humanos , Masculino , Força Muscular/fisiologia , Dinamômetro de Força Muscular , Músculo Esquelético/inervação , Torque
11.
Int J Sports Med ; 35(14): 1155-60, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25144438

RESUMO

The aim of this study was to evaluate the effects of a single partial-body cryotherapy bout between training sessions on strength recovery. 12 young men (23.9±5.9 years) were randomly exposed to 2 different conditions separated by 7 days: 1) Partial-body cryotherapy (subjects were exposed to 3 min of partial-body cryotherapy at - 110 °C between 2 high-intensity training sessions); 2) Control (subjects were not exposed to partial-body cryotherapy between 2 high-intensity training sessions). Subjects were exposed to partial-body cryotherapy after the first training session. The 2 knee extension high-intensity training sessions were separated by a 40-min rest interval. Knee extension training consisted of 6 sets of 10 repetitions at 60°.s(-1) for concentric actions and 6 sets of 10 at 180.s(-1) for eccentric actions. The decrease in eccentric peak torque and total work was significantly (p<0.05) less after partial-body cryotherapy (5.6 and 2%, respectively) when compared to control (16 and 11.6%, respectively). However, the decrease in concentric peak torque and total work was not different (p>0.05) between partial-body cryotherapy (9.4 and 6.5%, respectively) and control (7.5 and 5.2%, respectively). These results indicate that the use of partial-body cryotherapy between-training sessions can enhance eccentric muscle performance recovery.


Assuntos
Crioterapia , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Treinamento Resistido , Adulto , Humanos , Joelho/fisiologia , Masculino , Torque , Adulto Jovem
12.
Sci Total Environ ; 493: 1242-54, 2014 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-24650750

RESUMO

In alpine regions climatic change will alter the balance between water sources (rainfall, ice-melt, snowmelt, and groundwater) for aquatic systems, particularly modifying the relative contributions of meltwater, groundwater and rain to both rivers and lakes. While these changes are expected to have implications for alpine aquatic ecosystems, little is known about potential ecological tipping points and associated indicator taxa. We examined changes in biotic communities along a gradient of glacier influence for two study systems: (1) a stream network in the French Pyrénées; and (2) a network of lakes in the Italian Alps, with the aim of identifying potential indicator taxa (macroinvertebrates and zooplankton) of glacier retreat in these environments. To assess parallels in biotic responses across streams and lakes, both primary data and findings from other publications were synthesised. Using TITAN (Threshold Indicator Taxa ANalysis) changes in community composition of river taxa were identified at thresholds of <5.1% glacier cover and <66.6% meltwater contribution. Below these thresholds the loss of cold stenothermic benthic invertebrate taxa, Diamesa spp. and the Pyrenean endemic Rhyacophila angelieri was apparent. Some generalist taxa including Protonemura sp., Perla grandis, Baetis alpinus, Rhithrogena loyolaea and Microspectra sp. increased when glacier cover was <2.7% and <52% meltwater. Patterns were not as distinct for the alpine lakes, due to fewer sampling sites; however, Daphnia longispina grp. and the benthic invertebrate groups Plectopera and Planaria were identified as potential indicator taxa. While further work is required to assess potential indicator taxa for alpine lake systems, findings from alpine river systems were consistent between methods for assessing glacier influence (meltwater contribution/glacier cover). Hence, it is clear that TITAN could become a useful management tool, enabling: (i) the identification of taxa particularly sensitive to glacier retreat; and (ii) conservation efforts/resources to be better directed in alpine aquatic systems.


Assuntos
Biodiversidade , Monitoramento Ambiental/métodos , Invertebrados/crescimento & desenvolvimento , Animais , Ecossistema , Meio Ambiente , Invertebrados/classificação , Lagos , Rios
13.
J Theor Biol ; 353: 67-77, 2014 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-24650939

RESUMO

Understanding the Gene Regulatory Networks (GRNs) that underlie development is a major question for systems biology. The establishment of the germ layers is amongst the earliest events of development and has been characterised in numerous model systems. The establishment of the mesoderm is best characterised in the frog Xenopus laevis and has been well studied both experimentally and mathematically. However, the Xenopus network has significant differences from that in mouse and humans, including the presence of multiple copies of two key genes in the network, Mix and Nodal. The axolotl, a urodele amphibian, provides a model with all the benefits of amphibian embryology but crucially only a single Mix and Nodal gene required for the specification of the mesoderm. Remarkably, the number of genes within the network is not the only difference. The interaction between Mix and Brachyury, two transcription factors involved in the establishment of the endoderm and mesoderm respectively, is not conserved. While Mix represses Brachyury in Xenopus, it activates Brachyury in axolotl. Thus, whilst the topology of the networks in the two species differs, both are able to form mesoderm and endoderm in vivo. Based on current knowledge of the structure of the mesendoderm GRN we develop deterministic models that describe the time evolution of transcription factors in a single axolotl cell and compare numerical simulations with previous results from Xenopus. The models are shown to have stable steady states corresponding to mesoderm and anterior mesendoderm, with the in vitro model showing how the concentration of Activin can determine cell fate, while the in vivo model shows that ß-catenin concentration can determine cell fate. Moreover, our analysis suggests that additional components must be important in the axolotl network in the specification of the full range of tissues.


Assuntos
Anfíbios/embriologia , Anfíbios/genética , Padronização Corporal/genética , Endoderma/embriologia , Redes Reguladoras de Genes , Mesoderma/embriologia , Modelos Genéticos , Ambystoma mexicanum/embriologia , Ambystoma mexicanum/genética , Animais , Análise Numérica Assistida por Computador , Fatores de Tempo , Xenopus/embriologia , Xenopus/genética
14.
J Musculoskelet Neuronal Interact ; 13(1): 105-10, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23445920

RESUMO

OBJECTIVE: The current study examined serum CK activity following bench press (BP) and leg press (LP) exercise-induced muscle damage to evaluate agreement of subjects classification as either high (HiR) or normal responders (NoR) between upper and lower body muscle groups. METHODS: Forty-two men performed two resistance exercise bouts (BP and LP) of four sets of maximum repetitions to concentric failure at 10RM, following a random design. RESULTS: Fourteen subjects were classified as HiR after the BP and thirteen subjects after LP, while nine subjects were classified as HiR for both exercises. The analysis revealed good agreement (Kappa=0.528, with SE=0.137 and 95% confidence interval: from 0.259 to 0.798). Additionally, we found a significant moderate correlation (r=0.65, p<0.001) between CK peaks obtained following LP and BP. CONCLUSION: Our results suggest that exercise-induced muscle damage susceptibility is a whole body characteristic and is not body segment dependent. Thus, it may be that genetic or systemic mechanisms explain individual variation in muscle damage susceptibility.


Assuntos
Creatina Quinase/sangue , Músculo Esquelético/enzimologia , Músculo Esquelético/patologia , Levantamento de Peso/fisiologia , Adolescente , Adulto , Braço/fisiologia , Humanos , Perna (Membro)/fisiologia , Masculino , Adulto Jovem
15.
Int J Sports Med ; 31(12): 866-9, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21072739

RESUMO

The purpose of this study was to examine the effect of two between set rest intervals (RI) on isokinetic knee extension peak torque (PT) produced by sedentary women and men. Seventeen young women (27.18 ± 4.05 yrs) and 16 young men (26.75 ± 4.73 yrs) performed 3 sets of 10 unilateral isokinetic knee extension at 60° and 180°/s. The RI between sets was 60 and 120 s, counterbalanced across 2 testing days. Statistical evaluation of the data was performed using a 3-way mixed factor ANOVA (gender x rest interval x sets). Males and females exhibited decreases (p<0.05) in PT with 120 s RI at 60°/s. There was no significant decline in PT in the female group during both RI at 180°/s. Men showed a significant decrease in PT only with 60 s RI. Young women and men require more than 120 s of RI to recover full PT at 60°/s. However, full quadriceps's muscle strength recovery can be attained with a 60 and 120 s at 180°/s in women, but in men only with a 120 s at the same velocity.


Assuntos
Articulação do Joelho/fisiologia , Contração Muscular/fisiologia , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Adulto , Análise de Variância , Feminino , Humanos , Contração Isométrica/fisiologia , Masculino , Fatores Sexuais , Fatores de Tempo , Torque , Adulto Jovem
16.
Sci Total Environ ; 409(2): 256-66, 2010 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-21035169

RESUMO

Several recent studies have emphasised the need for a more integrated process in which researchers, policy makers and practitioners interact to identify research priorities. This paper discusses such a process with respect to the UK water sector, detailing how questions were developed through inter-disciplinary collaboration using online questionnaires and a stakeholder workshop. The paper details the 94 key questions arising, and provides commentary on their scale and scope. Prioritization voting divided the nine research themes into three categories: (1) extreme events (primarily flooding), valuing freshwater services, and water supply, treatment and distribution [each >150/1109 votes]; (2) freshwater pollution and integrated catchment management [100-150 votes] and; (3) freshwater biodiversity, water industry governance, understanding and managing demand and communicating water research [50-100 votes]. The biggest demand was for research to improve understanding of intervention impacts in the water environment, while a need for improved understanding of basic processes was also clearly expressed, particularly with respect to impacts of pollution and aquatic ecosystems. Questions that addressed aspects of appraisal, particularly incorporation of ecological service values into decision making, were also strongly represented. The findings revealed that sustainability has entered the lexicon of the UK water sector, but much remains to be done to embed the concept operationally, with key sustainability issues such as resilience and interaction with related key sectors, such as energy and agriculture, relatively poorly addressed. However, the exercise also revealed that a necessary condition for sustainable development, effective communication between scientists, practitioners and policy makers, already appears to be relatively well established in the UK water sector.


Assuntos
Política Ambiental , Formulação de Políticas , Poluição da Água/prevenção & controle , Biodiversidade , Água Doce/química , Pesquisa , Reino Unido , Poluentes da Água/análise , Poluição da Água/legislação & jurisprudência , Abastecimento de Água/análise , Abastecimento de Água/legislação & jurisprudência
17.
Int J Sports Med ; 31(1): 22-5, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19885775

RESUMO

The purpose of this study was to compare the effect of two different rest intervals between sets of isokinetic knee extension exercise on peak torque (PT), and Total Work (TW) between untrained younger and older men. Seventeen young men (24.22+/-2.58 yrs) and 20 older men (66.85+/-4.02 yrs) performed 3 sets of 10 unilateral isokinetic knee extension repetitions at 60 degrees /s. The rest intervals between sets were 1 and 2 min. There was a significant decline in PT when 1 and 2 min rest intervals were used for young men, but not when a 2 min rest interval was applied for old men. There was also a significant decline in TW among the 3 sets when 1 and 2 min rest intervals were applied for young men, whereas the decline in TW in older men occurred only between the 2(nd) and 3(rd) sets. PT and TW in the 3(rd) set were significant greater following a 2 min rest interval than a 1 min rest in both young and older men. The present study indicated that non-resistance trained young men may require longer rest interval to recover full PT and TW when compared to older men.


Assuntos
Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Treinamento Resistido , Descanso/fisiologia , Adulto , Fatores Etários , Idoso , Humanos , Joelho , Masculino , Pessoa de Meia-Idade , Fadiga Muscular/fisiologia , Fatores de Tempo , Torque , Adulto Jovem
18.
Rev Sci Tech ; 28(1): 175-85, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19618625

RESUMO

While the basic principles of immunity to the influenza A viruses are probably similar for all vertebrates, detailed understanding is based largely on experiments in laboratory mice. Elements of the innate response limit early virus replication, although high pathogenicity strains can trigger effusive cytokine/chemokine production and lethal shock. Virus clearance is normally mediated via CD8+ effector T cells but, in their absence, the class-switched antibody response can ultimately achieve the same goal. Protection against reinfection is optimally provided by antibody (IgG and IgA) specific for the homologous viral haemagglutinin, and priming against the neuraminidase and the low abundance, conserved M2 protein can also have an effect. Influenza virus-specific plasma cells and CD8+ T cells persist in the long term and the recall of the CD8+ T cell response can lead to earlier virus clearance. The characteristics of the aging immune system and possible, novel vaccine strategies are also considered.


Assuntos
Citocinas/biossíntese , Imunidade Inata , Vírus da Influenza A/imunologia , Influenza Humana/imunologia , Envelhecimento/imunologia , Animais , Aves , Reações Cruzadas , Citocinas/efeitos adversos , Citocinas/imunologia , Modelos Animais de Doenças , Humanos , Vírus da Influenza A/patogenicidade , Influenza Aviária/imunologia , Influenza Humana/virologia , Camundongos
19.
J Viral Hepat ; 15(10): 761-72, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18637077

RESUMO

SUMMARY: Serum-free culture conditions to generate immature human monocyte-derived DC (Mo-DC) were optimized, and the parameters that influence their maturation after exposure to lipopeptides containing CD4(+) and CD8(+) T-cell epitopes were examined. The lipopeptides contained a single CD4(+) helper T-cell epitopes, one of a number of human leucocyte antigen (HLA)-A2-restricted cytotoxic T-cell epitope and the lipid Pam2Cys. To ensure complete maturation of the Mo-DC, we examined (i) the optimal lipopeptide concentration, (ii) the optimal Mo-DC density and (iii) the appropriate period of exposure of the Mo-DC to the lipopeptides. The results showed that a high dose of lipopeptide (30 microm) was no more efficient at upregulating maturation markers on Mo-DC than a low dose (6 microm). There was an inverse relationship between Mo-DC concentration and the mean fluorescence intensity of maturation markers. In addition, at the higher cell concentrations, the chemotactic capacity of the Mo-DC towards a cognate ligand, CCL21, was reduced. Thus, high cell concentrations during lipopeptide exposure were detrimental to Mo-DC maturation and function. The duration of exposure of Mo-DC to the lipopeptides had little effect on phenotype, although Mo-DC exposed to lipopeptides for 48 rather than 4 h showed an increased ability to stimulate autologous peripheral blood mononuclear cells to release interferon-gamma in the absence of exogenous maturation factors. These findings reveal conditions for generating mature antigen-loaded DC suitable for targeted immunotherapy.


Assuntos
Células Dendríticas/citologia , Células Dendríticas/imunologia , Lipoproteínas/imunologia , Ativação Linfocitária , Peptídeos/imunologia , Linfócitos T/imunologia , Adulto , Sequência de Aminoácidos , Diferenciação Celular , Técnicas de Cocultura , Meios de Cultura Livres de Soro , Células Dendríticas/efeitos dos fármacos , Epitopos de Linfócito T/química , Humanos , Memória Imunológica , Lipoproteínas/síntese química , Lipoproteínas/química , Masculino , Pessoa de Meia-Idade , Monócitos/citologia , Peptídeos/síntese química , Peptídeos/química , Linfócitos T Citotóxicos/imunologia
20.
Electromyogr Clin Neurophysiol ; 48(2): 97-102, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18435213

RESUMO

The purpose of this study was to compare the composite and individual relationships for mechanomyographic (MMG) amplitude vs. torque during incremental isometric muscle actions. Ten women and six men (mean age +/- SD = 21.8 +/- 1.6 y) performed isometric leg extension muscle actions at 10-100% of peak isometric torque. Accelerometers were placed over the superficial quadriceps femoris muscles to detect the MMG signals. Polynomial regression analyses were used to determine the composite and individual patterns for MMG amplitude vs. isometric torque. The results indicated that the composite MMG amplitude vs. isometric torque relationships for all subjects combined were quadratic for the vastus lateralis and vastus medialis, and linear for the rectus femoris. The results of the individual analyses for the vastus lateralis revealed that the best fit model was linear for six subjects, quadratic for five subjects, cubic for three subjects, while two subjects exhibited no significant relationship. For the rectus femoris, eight subjects demonstrated linear patterns, six were quadratic, and two were cubic. For the vastus medialis, six subjects demonstrated linear patterns, four were quadratic, four were cubic, and two demonstrated no significant relationship. Examination of the patterns between muscles for each individual subject demonstrated that twelve of the sixteen subjects demonstrated different patterns for MMG amplitude vs. isometric torque for at least two of the three muscles examined. The results indicated there were differences in the patterns of responses for the composite MMG amplitude vs. isometric torque relationships for the three muscles. Furthermore, individual patterns for MMG amplitude frequently differed from the composite patterns, as well as between muscles. The results suggested that, in addition to using composite results of MMG responses, individual subject responses should be examined. Furthermore, caution should be used in generalizing the MMG responses of the quadriceps femoris muscles when examining a single muscle.


Assuntos
Eletromiografia , Contração Isométrica/fisiologia , Músculo Quadríceps/fisiologia , Adulto , Feminino , Humanos , Masculino , Análise de Regressão , Processamento de Sinais Assistido por Computador , Torque
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