Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 120
Filtrar
1.
NPJ Prim Care Respir Med ; 33(1): 6, 2023 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-36750578

RESUMO

Greater Manchester has a greater prevalence and worse asthma outcomes than the national average. This study aims to evaluate a digital approach to primary care asthma management and in particular the initial impact of implementing Clinical Decision Support System software in the form of a computer-guided consultation (CGC) in the setting of primary care asthma reviews in deprived areas of Greater Manchester. The CGC (LungHealth Ltd) is an intelligent decision support system ensuring accurate guideline-based staging of asthma and assessment of asthma control with the software subsequently prompting guideline-standard management. Patients on asthma registers in Greater Manchester Primary Care Networks were identified and underwent remote review by nursing staff using the CGC linked directly to the GP clinical system. Three-hundred thirty-eight patients (mean age 59 (SD 17) years; 60% Female) were reviewed. The CGC reported the patient's asthma control to be "Good" in 22%, "Partial" in 6% and "Poor" in 72%. ACT scores were significantly higher in those patients exhibiting "Good" and "Partial" control when compared to those with "Poor" control. The number of steroid courses and hospital admissions in the previous 12 months was significantly lower in those patients exhibiting "Good" and "Partial" control when compared to those with "Poor" control. Nineteen percent were found not to have a personalised asthma management plan during CGC review, which was alerted by the CGC and subsequently, all but 3 patients had this created on review completion (McNemar's test; p < 0.001). 5% were found not to have been prescribed regular inhaled steroid therapy resulting in the operator being alerted by the CGC in all cases. Overall, 44% underwent alteration in asthma therapy following the CGC review with 82% of these representing treatment escalation. An end-to-end digital service solution is feasible for Asthma within primary care and the utilisation of a CGC when conducting primary care asthma reviews increases implementation of guideline-level management thus addressing healthcare inequality while enabling identification of "high risk" asthma patients and guiding appropriate therapy escalation and de-escalation.


Assuntos
Asma , Disparidades nos Níveis de Saúde , Humanos , Feminino , Pessoa de Meia-Idade , Masculino , Estudos de Viabilidade , Asma/tratamento farmacológico , Encaminhamento e Consulta , Computadores
2.
Mol Autism ; 12(1): 74, 2021 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-34911565

RESUMO

BACKGROUND: The neurocognitive mechanisms underlying autism spectrum disorder (ASD) remain unclear. Progress has been largely hampered by small sample sizes, variable age ranges and resulting inconsistent findings. There is a pressing need for large definitive studies to delineate the nature and extent of key case/control differences to direct research towards fruitful areas for future investigation. Here we focus on perception of biological motion, a promising index of social brain function which may be altered in ASD. In a large sample ranging from childhood to adulthood, we assess whether biological motion preference differs in ASD compared to neurotypical participants (NT), how differences are modulated by age and sex and whether they are associated with dimensional variation in concurrent or later symptomatology. METHODS: Eye-tracking data were collected from 486 6-to-30-year-old autistic (N = 282) and non-autistic control (N = 204) participants whilst they viewed 28 trials pairing biological (BM) and control (non-biological, CTRL) motion. Preference for the biological motion stimulus was calculated as (1) proportion looking time difference (BM-CTRL) and (2) peak look duration difference (BM-CTRL). RESULTS: The ASD group showed a present but weaker preference for biological motion than the NT group. The nature of the control stimulus modulated preference for biological motion in both groups. Biological motion preference did not vary with age, gender, or concurrent or prospective social communicative skill within the ASD group, although a lack of clear preference for either stimulus was associated with higher social-communicative symptoms at baseline. LIMITATIONS: The paired visual preference we used may underestimate preference for a stimulus in younger and lower IQ individuals. Our ASD group had a lower average IQ by approximately seven points. 18% of our sample was not analysed for various technical and behavioural reasons. CONCLUSIONS: Biological motion preference elicits small-to-medium-sized case-control effects, but individual differences do not strongly relate to core social autism associated symptomatology. We interpret this as an autistic difference (as opposed to a deficit) likely manifest in social brain regions. The extent to which this is an innate difference present from birth and central to the autistic phenotype, or the consequence of a life lived with ASD, is unclear.


Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Adolescente , Biomarcadores , Estudos de Casos e Controles , Criança , Humanos , Índice de Gravidade de Doença , Adulto Jovem
3.
Nature ; 582(7811): 294-297, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32523118

RESUMO

The primary structural component of the bacterial cell wall is peptidoglycan, which is essential for viability and the synthesis of which is the target for crucial antibiotics1,2. Peptidoglycan is a single macromolecule made of glycan chains crosslinked by peptide side branches that surrounds the cell, acting as a constraint to internal turgor1,3. In Gram-positive bacteria, peptidoglycan is tens of nanometres thick, generally portrayed as a homogeneous structure that provides mechanical strength4-6. Here we applied atomic force microscopy7-12 to interrogate the morphologically distinct Staphylococcus aureus and Bacillus subtilis species, using live cells and purified peptidoglycan. The mature surface of live cells is characterized by a landscape of large (up to 60 nm in diameter), deep (up to 23 nm) pores constituting a disordered gel of peptidoglycan. The inner peptidoglycan surface, consisting of more nascent material, is much denser, with glycan strand spacing typically less than 7 nm. The inner surface architecture is location dependent; the cylinder of B. subtilis has dense circumferential orientation, while in S. aureus and division septa for both species, peptidoglycan is dense but randomly oriented. Revealing the molecular architecture of the cell envelope frames our understanding of its mechanical properties and role as the environmental interface13,14, providing information complementary to traditional structural biology approaches.


Assuntos
Bacillus subtilis/citologia , Bacillus subtilis/ultraestrutura , Parede Celular/química , Parede Celular/ultraestrutura , Microscopia de Força Atômica , Staphylococcus aureus/citologia , Staphylococcus aureus/ultraestrutura , Bacillus subtilis/química , Viabilidade Microbiana , Peptidoglicano/química , Peptidoglicano/isolamento & purificação , Peptidoglicano/ultraestrutura , Staphylococcus aureus/química
4.
Sci Rep ; 9(1): 17873, 2019 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-31784539

RESUMO

Fermionization is what happens to the state of strongly interacting repulsive bosons interacting with contact interactions in one spatial dimension. Crystallization is what happens for sufficiently strongly interacting repulsive bosons with dipolar interactions in one spatial dimension. Crystallization and fermionization resemble each other: in both cases - due to their repulsion - the bosons try to minimize their spatial overlap. We trace these two hallmark phases of strongly correlated one-dimensional bosonic systems by exploring their ground state properties using the one- and two-body density matrix. We solve the N-body Schrödinger equation accurately and from first principles using the multiconfigurational time-dependent Hartree for bosons (MCTDHB) and for fermions (MCTDHF) methods. Using the one- and two-body density, fermionization can be distinguished from crystallization in position space. For N interacting bosons, a splitting into an N-fold pattern in the one-body and two-body density is a unique feature of both, fermionization and crystallization. We demonstrate that this splitting is incomplete for fermionized bosons and restricted by the confinement potential. This incomplete splitting is a consequence of the convergence of the energy in the limit of infinite repulsion and is in agreement with complementary results that we obtain for fermions using MCTDHF. For crystalline bosons, in contrast, the splitting is complete: the interaction energy is capable of overcoming the confinement potential. Our results suggest that the spreading of the density as a function of the dipolar interaction strength diverges as a power law. We describe how to distinguish fermionization from crystallization experimentally from measurements of the one- and two-body density.

5.
Environ Monit Assess ; 191(4): 223, 2019 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-30879142

RESUMO

Phosphorus (P) demand is likely to increase especially in legumes to harness greater benefits of nitrogen fixation under elevated CO2 condition. In the following study, seed yield and seed P uptake in cowpea increased by 26.8% and 20.9%, respectively, under elevated CO2 level. With an increase in phosphorus dose up to 12 mg kg-1, seed yield enhanced from 2.6 to 5.4 g plant-1. P application and cyanobacterial inoculation increased the microbial activity of soil, leading to increased availability of P. Under elevated CO2 condition, microbial activity, measured as dehydrogenase, acid phosphatase, and alkaline phosphatase activities showed stimulation. Soil available P also increased under elevated CO2 condition and was stimulated by both P application and cyanobacterial inoculation. Higher P uptake in elevated CO2 condition led to lower values of inorganic P in soil. Stepwise regression analysis showed that aboveground P uptake, soil available P, and alkaline phosphatase activity of soil influenced the yield while available P, and organic and inorganic P influenced the aboveground P uptake of the crop. This study revealed that under elevated CO2 condition, P application and cyanobacterial inoculation facilitated P uptake and yield, mediated through enhanced availability of nutrients, in cowpea crop.


Assuntos
Dióxido de Carbono/metabolismo , Cianobactérias/metabolismo , Fósforo/metabolismo , Vigna/metabolismo , Carbono , Dióxido de Carbono/análise , Monitoramento Ambiental , Nitrogênio , Fixação de Nitrogênio , Análise de Regressão , Solo/química , Vigna/crescimento & desenvolvimento
6.
Nat Commun ; 9(1): 2331, 2018 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-29899421

RESUMO

The progress in the field of neural computation hinges on the use of hardware more efficient than the conventional microprocessors. Recent works have shown that mixed-signal integrated memristive circuits, especially their passive (0T1R) variety, may increase the neuromorphic network performance dramatically, leaving far behind their digital counterparts. The major obstacle, however, is immature memristor technology so that only limited functionality has been reported. Here we demonstrate operation of one-hidden layer perceptron classifier entirely in the mixed-signal integrated hardware, comprised of two passive 20 × 20 metal-oxide memristive crossbar arrays, board-integrated with discrete conventional components. The demonstrated network, whose hardware complexity is almost 10× higher as compared to previously reported functional classifier circuits based on passive memristive crossbars, achieves classification fidelity within 3% of that obtained in simulations, when using ex-situ training. The successful demonstration was facilitated by improvements in fabrication technology of memristors, specifically by lowering variations in their I-V characteristics.

7.
Mol Psychiatry ; 23(6): 1402-1409, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-28584286

RESUMO

We conducted a genome-wide meta-analysis of cognitive empathy using the 'Reading the Mind in the Eyes' Test (Eyes Test) in 88,056 research volunteers of European Ancestry (44,574 females and 43,482 males) from 23andMe Inc., and an additional 1497 research volunteers of European Ancestry (891 females and 606 males) from the Brisbane Longitudinal Twin Study. We confirmed a female advantage on the Eyes Test (Cohen's d=0.21, P<2.2 × 10-16), and identified a locus in 3p26.1 that is associated with scores on the Eyes Test in females (rs7641347, Pmeta=1.58 × 10-8). Common single nucleotide polymorphisms explained 5.8% (95% CI: 4.5%-7.2%; P=1.00 × 10-17) of the total trait variance in both sexes, and we identified a twin heritability of 28% (95% CI: 13%-42%). Finally, we identified significant genetic correlation between the Eyes Test and anorexia nervosa, openness (NEO-Five Factor Inventory), and different measures of educational attainment and cognitive aptitude.


Assuntos
Empatia/genética , Empatia/fisiologia , Adulto , Idoso , Anorexia Nervosa/genética , Cognição/fisiologia , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Masculino , Transtornos Mentais/genética , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Fatores Sexuais , Gêmeos , População Branca/genética
9.
Transl Psychiatry ; 7(4): e1090, 2017 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-28398337

RESUMO

Autism spectrum conditions (ASC) are more prevalent in males than females. The biological basis of this difference remains unclear. It has been postulated that one of the primary causes of ASC is a partial disconnection of the frontal lobe from higher-order association areas during development (that is, a frontal 'disconnection syndrome'). Therefore, in the current study we investigated whether frontal connectivity differs between males and females with ASC. We recruited 98 adults with a confirmed high-functioning ASC diagnosis (61 males: aged 18-41 years; 37 females: aged 18-37 years) and 115 neurotypical controls (61 males: aged 18-45 years; 54 females: aged 18-52 years). Current ASC symptoms were evaluated using the Autism Diagnostic Observation Schedule (ADOS). Diffusion tensor imaging was performed and fractional anisotropy (FA) maps were created. Mean FA values were determined for five frontal fiber bundles and two non-frontal fiber tracts. Between-group differences in mean tract FA, as well as sex-by-diagnosis interactions were assessed. Additional analyses including ADOS scores informed us on the influence of current ASC symptom severity on frontal connectivity. We found that males with ASC had higher scores of current symptom severity than females, and had significantly lower mean FA values for all but one tract compared to controls. No differences were found between females with or without ASC. Significant sex-by-diagnosis effects were limited to the frontal tracts. Taking current ASC symptom severity scores into account did not alter the findings, although the observed power for these analyses varied. We suggest these findings of frontal connectivity abnormalities in males with ASC, but not in females with ASC, have the potential to inform us on some of the sex differences reported in the behavioral phenotype of ASC.


Assuntos
Transtorno do Espectro Autista/diagnóstico por imagem , Transtorno do Espectro Autista/patologia , Imagem de Tensor de Difusão , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/patologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/patologia , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores Sexuais , Adulto Jovem
10.
Sci Rep ; 7: 42429, 2017 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-28195239

RESUMO

Silicon (Si) based complementary metal-oxide semiconductor (CMOS) technology has been the driving force of the information-technology revolution. However, scaling of CMOS technology as per Moore's law has reached a serious bottleneck. Among the emerging technologies memristive devices can be promising for both memory as well as computing applications. Hybrid CMOS/memristor circuits with CMOL (CMOS + "Molecular") architecture have been proposed to combine the extremely high density of the memristive devices with the robustness of CMOS technology, leading to terabit-scale memory and extremely efficient computing paradigm. In this work, we demonstrate a hybrid 3D CMOL circuit with 2 layers of memristive crossbars monolithically integrated on a pre-fabricated CMOS substrate. The integrated crossbars can be fully operated through the underlying CMOS circuitry. The memristive devices in both layers exhibit analog switching behavior with controlled tunability and stable multi-level operation. We perform dot-product operations with the 2D and 3D memristive crossbars to demonstrate the applicability of such 3D CMOL hybrid circuits as a multiply-add engine. To the best of our knowledge this is the first demonstration of a functional 3D CMOL hybrid circuit.

11.
Sci Rep ; 6: 27751, 2016 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-27297317

RESUMO

We tend to like those who mimic us. In this study we formally test if mimicry changes the reward value of the mimicker, using gaze bias as a proxy for reward. Previous research has demonstrated that people show gaze bias towards more rewarding targets, suggesting that gaze bias can be considered a proxy for relative reward value. Forty adults participated in a conditioning task, where they were mimicked by one face and 'anti-mimicked' by another. Subsequently, they were found to show gaze-bias towards faces that mimicked them compared to those that did not, in a preferential looking task. The strength of this effect correlated positively with individual levels of trait empathy. In a separate, similar task, these participants showed a gaze bias for faces paired with high vs low monetary rewards, thus validating the use of gaze bias as a proxy for learnt reward. Together, these results demonstrate that mimicry changes the reward value of social stimuli, and empathy influences the extent of this change. This can potentially inform conditions marked by deficits in forming social bonds, such as Autism.


Assuntos
Comportamento , Empatia , Recompensa , Adulto , Viés , Feminino , Fixação Ocular , Humanos , Masculino
12.
Transl Psychiatry ; 5: e507, 2015 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-25668435

RESUMO

Autism spectrum conditions (autism) affect ~1% of the population and are characterized by deficits in social communication. Oxytocin has been widely reported to affect social-communicative function and its neural underpinnings. Here we report the first evidence that intranasal oxytocin administration improves a core problem that individuals with autism have in using eye contact appropriately in real-world social settings. A randomized double-blind, placebo-controlled, within-subjects design is used to examine how intranasal administration of 24 IU of oxytocin affects gaze behavior for 32 adult males with autism and 34 controls in a real-time interaction with a researcher. This interactive paradigm bypasses many of the limitations encountered with conventional static or computer-based stimuli. Eye movements are recorded using eye tracking, providing an objective measurement of looking patterns. The measure is shown to be sensitive to the reduced eye contact commonly reported in autism, with the autism group spending less time looking to the eye region of the face than controls. Oxytocin administration selectively enhanced gaze to the eyes in both the autism and control groups (transformed mean eye-fixation difference per second=0.082; 95% CI:0.025-0.14, P=0.006). Within the autism group, oxytocin has the most effect on fixation duration in individuals with impaired levels of eye contact at baseline (Cohen's d=0.86). These findings demonstrate that the potential benefits of oxytocin in autism extend to a real-time interaction, providing evidence of a therapeutic effect in a key aspect of social communication.


Assuntos
Síndrome de Asperger/tratamento farmacológico , Transtorno Autístico/tratamento farmacológico , Fixação Ocular , Relações Interpessoais , Ocitócicos/uso terapêutico , Ocitocina/uso terapêutico , Comportamento Social , Administração Intranasal , Adolescente , Adulto , Estudos de Casos e Controles , Método Duplo-Cego , Medições dos Movimentos Oculares , Humanos , Masculino , Pessoa de Meia-Idade , Habilidades Sociais , Adulto Jovem
13.
Mol Psychiatry ; 20(3): 369-76, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24888361

RESUMO

Autism affects males more than females, giving rise to the idea that the influence of steroid hormones on early fetal brain development may be one important early biological risk factor. Utilizing the Danish Historic Birth Cohort and Danish Psychiatric Central Register, we identified all amniotic fluid samples of males born between 1993 and 1999 who later received ICD-10 (International Classification of Diseases, 10th Revision) diagnoses of autism, Asperger syndrome or PDD-NOS (pervasive developmental disorder not otherwise specified) (n=128) compared with matched typically developing controls. Concentration levels of Δ4 sex steroids (progesterone, 17α-hydroxy-progesterone, androstenedione and testosterone) and cortisol were measured with liquid chromatography tandem mass spectrometry. All hormones were positively associated with each other and principal component analysis confirmed that one generalized latent steroidogenic factor was driving much of the variation in the data. The autism group showed elevations across all hormones on this latent generalized steroidogenic factor (Cohen's d=0.37, P=0.0009) and this elevation was uniform across ICD-10 diagnostic label. These results provide the first direct evidence of elevated fetal steroidogenic activity in autism. Such elevations may be important as epigenetic fetal programming mechanisms and may interact with other important pathophysiological factors in autism.


Assuntos
Síndrome de Asperger/sangue , Transtorno Autístico/sangue , Feto/metabolismo , Esteroides/metabolismo , Análise de Variância , Estudos de Casos e Controles , Cromatografia Líquida , Estudos de Coortes , Dinamarca , Feminino , Idade Gestacional , Humanos , Hidrocortisona/metabolismo , Masculino , Análise de Componente Principal , Espectrometria de Massas em Tandem
14.
Neuropsychologia ; 51(1): 98-105, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23174401

RESUMO

Empathy is the lens through which we view others' emotion expressions, and respond to them. In this study, empathy and facial emotion recognition were investigated in adults with autism spectrum conditions (ASC; N=314), parents of a child with ASC (N=297) and IQ-matched controls (N=184). Participants completed a self-report measure of empathy (the Empathy Quotient [EQ]) and a modified version of the Karolinska Directed Emotional Faces Task (KDEF) using an online test interface. Results showed that mean scores on the EQ were significantly lower in fathers (p<0.05) but not mothers (p>0.05) of children with ASC compared to controls, whilst both males and females with ASC obtained significantly lower EQ scores (p<0.001) than controls. On the KDEF, statistical analyses revealed poorer overall performance by adults with ASC (p<0.001) compared to the control group. When the 6 distinct basic emotions were analysed separately, the ASC group showed impaired performance across five out of six expressions (happy, sad, angry, afraid and disgusted). Parents of a child with ASC were not significantly worse than controls at recognising any of the basic emotions, after controlling for age and non-verbal IQ (all p>0.05). Finally, results indicated significant differences between males and females with ASC for emotion recognition performance (p<0.05) but not for self-reported empathy (p>0.05). These findings suggest that self-reported empathy deficits in fathers of autistic probands are part of the 'broader autism phenotype'. This study also reports new findings of sex differences amongst people with ASC in emotion recognition, as well as replicating previous work demonstrating empathy difficulties in adults with ASC. The use of empathy measures as quantitative endophenotypes for ASC is discussed.


Assuntos
Transtorno Autístico , Empatia , Família , Transtornos do Humor/etiologia , Reconhecimento Visual de Modelos/fisiologia , Transtornos da Personalidade/etiologia , Adulto , Transtorno Autístico/complicações , Transtorno Autístico/genética , Transtorno Autístico/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos do Humor/genética , Testes Neuropsicológicos , Transtornos da Personalidade/genética , Estimulação Luminosa , Escalas de Graduação Psiquiátrica
15.
Phys Rev E Stat Nonlin Soft Matter Phys ; 86(2 Pt 1): 021910, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23005788

RESUMO

We show that polarons can sustain looplike configurations in flexible biopolymers and that the size of the loops depend on both the flexural rigidity of the polymer and the electron-phonon coupling constant. In particular we show that for single stranded DNA (ssDNA) and polyacetylene such loops can have as few as seven monomers. We also show that these configurations are very stable under thermal fluctuations and so could facilitate the formation of hairpin loops of ssDNA.


Assuntos
Biopolímeros/química , Elétrons , Conformação Molecular , DNA de Cadeia Simples/química , DNA de Cadeia Simples/genética , Sequências Repetidas Invertidas , Poli-Inos/química
17.
Neuroimage ; 59(2): 1571-81, 2012 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-21906686

RESUMO

Research on the cortical sources of nociceptive laser-evoked brain potentials (LEPs) began almost two decades ago (Tarkka and Treede, 1993). Whereas there is a large consensus on the sources of the late part of the LEP waveform (N2 and P2 waves), the relative contribution of the primary somatosensory cortex (S1) to the early part of the LEP waveform (N1 wave) is still debated. To address this issue we recorded LEPs elicited by the stimulation of four limbs in a large population (n=35). Early LEP generators were estimated both at single-subject and group level, using three different approaches: distributed source analysis, dipolar source modeling, and probabilistic independent component analysis (ICA). We show that the scalp distribution of the earliest LEP response to hand stimulation was maximal over the central-parietal electrodes contralateral to the stimulated side, while that of the earliest LEP response to foot stimulation was maximal over the central-parietal midline electrodes. Crucially, all three approaches indicated hand and foot S1 areas as generators of the earliest LEP response. Altogether, these findings indicate that the earliest part of the scalp response elicited by a selective nociceptive stimulus is largely explained by activity in the contralateral S1, with negligible contribution from the secondary somatosensory cortex (S2).


Assuntos
Eletroencefalografia/métodos , Potenciais Somatossensoriais Evocados , Dor Nociceptiva/fisiopatologia , Córtex Somatossensorial/fisiopatologia , Adulto , Feminino , Humanos , Masculino
18.
J Virol ; 85(16): 8217-26, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21653673

RESUMO

On the prereceptor-engaged HIV-1 envelope glycoprotein (Env) spike, epitope access by the membrane-proximal external region (MPER)-directed broadly neutralizing antibodies 2F5 and 4E10 remains unresolved. Data on binding to cell surface Env and entry data using primary isolates suggest inaccessibility of the 2F5 and 4E10 epitopes on the viral spike prior to receptor engagement, but trimer gel shift analysis and slow kinetics of shedding induced by 2F5 and 4E10 indicate otherwise. Therefore, it remains unclear if the epitopes themselves are formed in their antibody-bound state (or at least sampled) prior to receptor/coreceptor engagement or if receptor interactions both expose and form the MPER epitopes, presumably in the putative prefusion transitional intermediate. Here, we performed antibody-virus "washout experiments" using both lab-adapted and a panel of clade B primary isolates to analyze MPER accessibility. The neutralization activity of 2F5 and 4E10 against lab-adapted viruses and sensitive and moderately resistant viruses was largely unaffected by relatively rapid antibody-virus washing, suggesting direct interaction with the "static" spike. However, for more neutralization-resistant viruses, the 2F5 and 4E10 antibodies could neutralize only under the "no antibody-virus wash" conditions, implying that the MPER epitopes were not accessible prior to receptor engagement. Accessibility in the washout conditions could be precisely predicted by the relative resistance to neutralization in a standard neutralization format. These data are consistent with a model in which the local MPER antibody epitope conformations may be sampled on the native spike but are occluded to antibody by local steric or distal quaternary constraints adopted by highly resistant HIV-1 isolates.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp160 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/imunologia , Anticorpos Monoclonais/metabolismo , Anticorpos Neutralizantes/metabolismo , Afinidade de Anticorpos , Sítios de Ligação de Anticorpos , Citometria de Fluxo , Células HEK293 , Anticorpos Anti-HIV/metabolismo , Proteína gp120 do Envelope de HIV/metabolismo , Proteína gp160 do Envelope de HIV/metabolismo , Proteína gp41 do Envelope de HIV/metabolismo , Células HeLa , Humanos , Testes de Neutralização , Estrutura Quaternária de Proteína
19.
Phys Biol ; 7(2): 026003, 2010 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-20453297

RESUMO

Chemotaxis is typically modeled in the context of cellular motion toward a static, exogenous source of chemoattractant. Here we propose a time-dependent mechanism of chemotaxis in which a self-propelled particle (e.g. a cell) releases a chemical that diffuses to fixed particles (targets) and signals the production of a second chemical by these targets. The particle then moves up concentration gradients of this second chemical, analogous to diffusive echolocation. When one target is present, we describe probe release strategies that optimize travel of the cell to the target. In the presence of multiple targets, the one selected by the cell depends on the strength and, interestingly, on the frequency of probe chemical release. Although involving an additional chemical signaling step, our chemical 'pinging' hypothesis allows for greater flexibility in regulating target selection, as seen in a number of physical or biological realizations.


Assuntos
Fatores Quimiotáticos/metabolismo , Quimiotaxia , Comunicação Celular , Modelos Biológicos
20.
Curr Oncol ; 16(4): 71-3, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19672428

RESUMO

Hemangiopericytoma is a malignant vascular tumour of soft tissue. Microscopically, the tumour shows tightly packed cellular areas surrounding thin-walled branching blood vessels. Traditionally these tumours are treated using wide surgical excision. Only a very few cases of hemangiopericytoma of the prostate have been described worldwide. The feasibility of managing such a case with a combination of conservative surgery and adjuvant anti-malignancy treatment is unexplored. Here, we report a case of hemangiopericytoma of the prostate treated with local excision, with preservation of prostate, followed by adjuvant radiotherapy (40 Gy in 20 fractions to pelvis followed by 24 Gy in 12 fractions as boost to prostate) and chemotherapy (doxorubicin and iphosphamide). Post-treatment computed tomography scan after 4 weeks showed regression of pelvic lymph nodes and a normal-appearing prostate. Levels of serum prostate-specific and carcinogenic embryonic antigen were normal throughout the period of treatment. To date, followup has been uneventful, except for occasional bouts of diarrhea.We conclude that conservative surgery followed by adjuvant radiation and chemotherapy, with subsequent close follow-up, may adequately control localized disease in selected cases of hemangiopericytoma of the prostate. The role of conservative surgery in tumours located at other sites has yet to be defined.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...