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In this review, we provide an update on the intensive care unit (ICU) management of ischemic stroke. Over the last decade, new evidence has led to rapid changes in the early management of patients admitted with acute ischemic stroke. Nevertheless, stroke remains a leading cause of disability. Consequently, a significant number of patients with acute ischemic stroke require ICU level care. The most frequent reasons for ICU admissions are large infarction with potential swelling, reduced level of consciousness, secondary hemorrhagic transformation, acute symptomatic seizures or respiratory failure and stroke-related disorders of the brain-heart interaction. Moreover, there is an increasing number of patients receiving intravenous thrombolysis or mechanical thrombectomy with a subsequent need of ICU monitoring. Several studies have shown that the implementation of specialized neuro-intensive care teams help to improve functional outcome after acute ischemic stroke. The main goal in the ICU management of stroke patients is to prevent secondary brain injury. To this end, a comprehensive approach to optimize systemic physiological homeostasis, control intracranial pressure, cerebral perfusion, hemodynamic and respiratory parameters is needed. Here, we summarize recent advances in invasive and non-invasive neuro-monitoring, decision making in decompressive neurosurgery for large supratentorial or cerebellar infarction, specific cardiorespiratory management, nutrition, temperature management and mobilization strategies in ischemic stroke.
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Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Cuidados Críticos , Humanos , Unidades de Terapia Intensiva , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/terapiaRESUMO
RATIONALE: New strategies in the field of cardiac regeneration are directed at identifying proliferation-inducing substances to induce regrowth of myocardium. Current screening assays utilize neonatal cardiomyocytes and markers for cytokinesis, such as Aurora B-kinase. However, detection of cardiomyocyte division is complicated because of cell cycle variants, in particular, binucleation. OBJECTIVE: To analyze the process of cardiomyocyte binucleation to identify definitive discriminators for cell cycle variants and authentic cardiomyocyte division. METHODS AND RESULTS: Herein, we demonstrate by direct visualization of the contractile ring and midbody in Myh6 (myosin, heavy chain 6)-eGFP (enhanced green fluorescent protein)-anillin transgenic mice that cardiomyocyte binucleation starts by formation of a contractile ring. This is followed by irregular positioning of the midbody and movement of the 2 nuclei into close proximity to each other. In addition, the widespread used marker Aurora B-kinase was found to also label binucleating cardiomyocytes, complicating the interpretation of existing screening assays. Instead, atypical midbody positioning and the distance of daughter nuclei on karyokinesis are bona fide markers for cardiomyocyte binucleation enabling to unequivocally discern such events from cardiomyocyte division in vitro and in vivo. CONCLUSIONS: The 2 criteria provide a new method for identifying cardiomyocyte division and should be considered in future studies investigating cardiomyocyte turnover and regeneration after injury, in particular in the postnatal heart to prevent the assignment of false positive proliferation events.
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Divisão do Núcleo Celular , Núcleo Celular/fisiologia , Proliferação de Células , Miócitos Cardíacos/fisiologia , Animais , Aurora Quinase B/metabolismo , Biomarcadores/metabolismo , Núcleo Celular/metabolismo , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Feminino , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Masculino , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , MicroRNAs/genética , MicroRNAs/metabolismo , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Miócitos Cardíacos/metabolismo , Cadeias Pesadas de Miosina/genética , Regeneração , Fatores de TempoRESUMO
Water molecules confined in a nanocavity possess distinctly different characteristics from those in bulk, yet the preparation of such nanocavities is still a major experimental challenge. We report here a self-assembled vesicle of an anionic perfluoroalkylated [60]fullerene, unique for its outstanding stability and water tightness, containing water not bound to the membranes. Small-angle neutron scattering revealed that a vesicle of 14 nm outer radius contains a 2 nm thick fullerene bilayer, inside of which is a 3 nm thick membrane-bound water and unbound water in the 4 nm innermost cavity. The vesicle shows astonishingly low water permeability that is 6 to 9 orders of magnitude smaller than that of a lipid vesicle. As a result, a single vesicle isolated on a substrate can retain the interior water in air or even under high vacuum, indicating that the vesicle cavity provides a new tool for physicochemical studies of confined water as well as ions and molecules dissolved in it.
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A recent analysis using family history weighting and co-observation classification modeling indicated that BRCA1 c.594-2A > C (IVS9-2A > C), previously described to cause exon 10 skipping (a truncating alteration), displays characteristics inconsistent with those of a high risk pathogenic BRCA1 variant. We used large-scale genetic and clinical resources from the ENIGMA, CIMBA and BCAC consortia to assess pathogenicity of c.594-2A > C. The combined odds for causality considering case-control, segregation and breast tumor pathology information was 3.23 × 10-8 Our data indicate that c.594-2A > C is always in cis with c.641A > G. The spliceogenic effect of c.[594-2A > C;641A > G] was characterized using RNA analysis of human samples and splicing minigenes. As expected, c.[594-2A > C; 641A > G] caused exon 10 skipping, albeit not due to c.594-2A > C impairing the acceptor site but rather by c.641A > G modifying exon 10 splicing regulatory element(s). Multiple blood-based RNA assays indicated that the variant allele did not produce detectable levels of full-length transcripts, with a per allele BRCA1 expression profile composed of ≈70-80% truncating transcripts, and ≈20-30% of in-frame Δ9,10 transcripts predicted to encode a BRCA1 protein with tumor suppression function.We confirm that BRCA1c.[594-2A > C;641A > G] should not be considered a high-risk pathogenic variant. Importantly, results from our detailed mRNA analysis suggest that BRCA-associated cancer risk is likely not markedly increased for individuals who carry a truncating variant in BRCA1 exons 9 or 10, or any other BRCA1 allele that permits 20-30% of tumor suppressor function. More generally, our findings highlight the importance of assessing naturally occurring alternative splicing for clinical evaluation of variants in disease-causing genes.
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Proteína BRCA1/genética , Neoplasias da Mama/genética , Mutação/genética , Neoplasias Ovarianas/genética , Proteínas Supressoras de Tumor/genética , Adulto , Idoso , Processamento Alternativo/genética , Neoplasias da Mama/patologia , Análise Mutacional de DNA , Éxons/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Pessoa de Meia-Idade , Neoplasias Ovarianas/patologia , Sítios de Splice de RNA/genética , Splicing de RNA/genéticaRESUMO
Endothelial cell proliferation is a key process during vascular growth but its kinetics could only be assessed in vitro or ex vivo so far. To enable the monitoring and quantification of cell cycle kinetics in vivo, we have generated transgenic mice expressing an eGFP-anillin construct under control of the endothelial-specific Flt-1 promoter. This construct labels the nuclei of endothelial cells in late G1, S and G2 phase and changes its localization during the different stages of M phase, thereby enabling the monitoring of EC proliferation and cytokinesis. In Flt-1/eGFP-anillin mice, we found eGFP+ signals specifically in Ki67+/PECAM+ endothelial cells during vascular development. Quantification using this cell cycle reporter in embryos revealed a decline in endothelial cell proliferation between E9.5 to E12.5. By time-lapse microscopy, we determined the length of different cell cycle phases in embryonic endothelial cells in vivo and found a M phase duration of about 80 min with 2/3 covering karyokinesis and 1/3 cytokinesis. Thus, we have generated a versatile transgenic system for the accurate assessment of endothelial cell cycle dynamics in vitro and in vivo.
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Ciclo Celular , Proteínas Contráteis/metabolismo , Embrião de Mamíferos/metabolismo , Células Endoteliais/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Animais , Proteínas Contráteis/genética , Embrião de Mamíferos/citologia , Células Endoteliais/citologia , Proteínas de Fluorescência Verde/genética , Camundongos , Camundongos Transgênicos , Regiões Promotoras Genéticas , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/genéticaRESUMO
BACKGROUND: BRCA1 and BRCA2 are the two principal tumour suppressor genes associated with inherited high risk of breast and ovarian cancer. Genetic testing of BRCA1/2 will often reveal one or more sequence variants of uncertain clinical significance, some of which may affect normal splicing patterns and thereby disrupt gene function. mRNA analyses are therefore among the tests used to interpret the clinical significance of some genetic variants. However, these could be confounded by the appearance of naturally occurring alternative transcripts unrelated to germline sequence variation or defects in gene function. To understand which novel splicing events are associated with splicing mutations and which are part of the normal BRCA2 splicing repertoire, a study was undertaken by members of the Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA) consortium to characterise the spectrum of naturally occurring BRCA2 mRNA alternate-splicing events. METHODS: mRNA was prepared from several blood and breast tissue-derived cells and cell lines by contributing ENIGMA laboratories. cDNA representing BRCA2 alternate splice sites was amplified and visualised using capillary or agarose gel electrophoresis, followed by sequencing. RESULTS: We demonstrate the existence of 24 different BRCA2 mRNA alternate-splicing events in lymphoblastoid cell lines and both breast cancer and non-cancerous breast cell lines. CONCLUSIONS: These naturally occurring alternate-splicing events contribute to the array of cDNA fragments that may be seen in assays for mutation-associated splicing defects. Caution must be observed in assigning alternate-splicing events to potential splicing mutations.
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Processamento Alternativo/genética , Proteína BRCA2/genética , RNA Mensageiro/genética , Proteína BRCA1/genética , Neoplasias da Mama/genética , Linhagem Celular , Linhagem Celular Tumoral , Feminino , Predisposição Genética para Doença/genética , Testes Genéticos/métodos , Humanos , Células MCF-7 , Mutação/genética , Neoplasias Ovarianas/genética , Sítios de Splice de RNA/genéticaRESUMO
Loss-of-function germline mutations in BRCA1 (MIM #113705) confer markedly increased risk of breast and ovarian cancer. The full-length transcript codifies for a protein involved in DNA repair pathways and cell-cycle checkpoints. Several BRCA1 splicing isoforms have been described in public domain databases, but the physiological role (if any) of BRCA1 alternative splicing remains to be established. An accurate description of 'naturally occurring' alternative splicing at this locus is a prerequisite to understand its biological significance. However, a systematic analysis of alternative splicing at the BRCA1 locus is yet to be conducted. Here, the Evidence-Based Network for the Interpretation of Germ-Line Mutant Alleles consortium combines RT-PCR, exon scanning, cloning, sequencing and relative semi-quantification to describe naturally occurring BRCA1 alternative splicing with unprecedented resolution. The study has been conducted in blood-related RNA sources, commonly used for clinical splicing assays, as well as in one healthy breast tissue. We have characterized a total of 63 BRCA1 alternative splicing events, including 35 novel findings. A minimum of 10 splicing events (Δ1Aq, Δ5, Δ5q, Δ8p, Δ9, Δ(9,10), Δ9_11, Δ11q, Δ13p and Δ14p) represent a substantial fraction of the full-length expression level (ranging from 5 to 100%). Remarkably, our data indicate that BRCA1 alternative splicing is similar in blood and breast, a finding supporting the clinical relevance of blood-based in vitro splicing assays. Overall, our data suggest an alternative splicing model in which most non-mutually exclusive alternative splicing events are randomly combined into individual mRNA molecules to produce hundreds of different BRCA1 isoforms.
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Processamento Alternativo , Proteína BRCA1/sangue , Proteína BRCA1/genética , Mama/metabolismo , Feminino , Humanos , Isoformas de Proteínas/genética , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de RNARESUMO
Vigilance, or sustained attention, is a required ability in many operational professions. While past research has consistently indicated that vigilance performance declines over time, referred to as the vigilance decrement, the theoretical mechanisms underlying the decrement continue to be explored. In the current study, trait self-control was examined to determine how this individual differences measure may contribute to the theoretical explanation of vigilance decrement. Transcranial Doppler sonography (TCD) was used as a measure of cerebral blood flow velocity (CBFV), as previous research has indicated that CBFV may index attentional resource allocation during vigilance (e.g., Shaw et al. in Hum Factors Ergon Soc 50:1619-1623, 2009). Participants performed a demanding 12-min computer-based vigilance task. Prior to the task, a validated self-report measure was used to determine trait-level self-control, and subjective workload was measured after the task was completed. Participants were divided, based upon survey responses, as either low- or high-trait self-control. Performance results showed a significant decrement across participants, but no significant main effect or interaction relating to the self-control measure was observed. Results relating to the TCD measure showed a significant decline in CBFV in the low self-control group, but no CBFV decrement was observed in the high self-control group. The subjective workload results revealed a nonsignificant trend of the low self-control group becoming more frustrated after the task. These results suggest that there are differences in the resource allocation strategies between low and high self-control participants. How trait self-control can add to an understanding of the theoretical underpinnings of sustained attention performance is discussed.
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Atenção/fisiologia , Circulação Cerebrovascular/fisiologia , Cognição/fisiologia , Alocação de Recursos , Autocontrole , Adolescente , Adulto , Análise de Variância , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Tempo de Reação , Ultrassonografia Doppler Transcraniana , Adulto JovemRESUMO
Selecting for vigilance assignments remains an important factor in human performance research. The current study revisits the potential relationship between vigilance performance and trait neuroticism, in light of two possible theories. The first theory suggests that neuroticism impairs vigilance performance by competing for available resources. The second theory, attentional control theory, posits that high neuroticism can result in similar or superior performance levels due to the allocation of compensatory effort. In the present study, Transcranial Doppler Sonography was used to investigate the neurophysiological underpinnings of neuroticism during a 12-min abbreviated vigilance task. Performance results were not modified by level of neuroticism, but high neuroticism was associated with higher initial CBFV levels and a greater CBFV decrement over time. These findings indicate that participants higher in neuroticism recruited additional cognitive resources in order to achieve similar performance, suggesting that there is more of an effect on processing efficiency than effectiveness.
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Transtornos de Ansiedade/fisiopatologia , Nível de Alerta/fisiologia , Circulação Cerebrovascular/fisiologia , Desempenho Psicomotor/fisiologia , Ultrassonografia Doppler Transcraniana/métodos , Adolescente , Adulto , Atenção/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Feminino , Humanos , Masculino , Neuroticismo , Adulto JovemRESUMO
BACKGROUND: Accurate evaluation of unclassified sequence variants in cancer predisposition genes is essential for clinical management and depends on a multifactorial analysis of clinical, genetic, pathologic, and bioinformatic variables and assays of transcript length and abundance. The integrity of assay data in turn relies on appropriate assay design, interpretation, and reporting. METHODS: We conducted a multicenter investigation to compare mRNA splicing assay protocols used by members of the ENIGMA (Evidence-Based Network for the Interpretation of Germline Mutant Alleles) consortium. We compared similarities and differences in results derived from analysis of a panel of breast cancer 1, early onset (BRCA1) and breast cancer 2, early onset (BRCA2) gene variants known to alter splicing (BRCA1: c.135-1G>T, c.591C>T, c.594-2A>C, c.671-2A>G, and c.5467+5G>C and BRCA2: c.426-12_8delGTTTT, c.7988A>T, c.8632+1G>A, and c.9501+3A>T). Differences in protocols were then assessed to determine which elements were critical in reliable assay design. RESULTS: PCR primer design strategies, PCR conditions, and product detection methods, combined with a prior knowledge of expected alternative transcripts, were the key factors for accurate splicing assay results. For example, because of the position of primers and PCR extension times, several isoforms associated with BRCA1, c.594-2A>C and c.671-2A>G, were not detected by many sites. Variation was most evident for the detection of low-abundance transcripts (e.g., BRCA2 c.8632+1G>A Δ19,20 and BRCA1 c.135-1G>T Δ5q and Δ3). Detection of low-abundance transcripts was sometimes addressed by using more analytically sensitive detection methods (e.g., BRCA2 c.426-12_8delGTTTT ins18bp). CONCLUSIONS: We provide recommendations for best practice and raise key issues to consider when designing mRNA assays for evaluation of unclassified sequence variants.
Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Testes Genéticos/métodos , Testes Genéticos/normas , Laboratórios/normas , Splicing de RNA , Predisposição Genética para Doença , Humanos , Análise Multivariada , Guias de Prática Clínica como Assunto , Sítios de Splice de RNA , Sensibilidade e EspecificidadeRESUMO
RAD51C is an integral part of the DNA double-strand repair through homologous recombination, and monoallelic mutations were found in ~1.3% of BRCA1/2-negative breast cancer (BC) and/or ovarian cancer (OC) families. Several studies confirmed the occurrence of RAD51C mutations predominantly in BC and/or OC families, although with varying frequencies, clearly establishing RAD51C as a cancer-predisposing gene. There is ongoing debate whether pathogenic RAD51C alterations increase the relative risk for BC in addition to that for OC, which was estimated to be 5.88 (95% confidence interval = 2.91 to 11.88; P = 7.65 × 10(-7)).
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Neoplasias da Mama/genética , Neoplasias Ovarianas/genética , Rad51 Recombinase/genética , Adulto , Feminino , Deleção de Genes , Humanos , LinhagemRESUMO
Numerous allelic variants identified in the familial breast cancer and DNA repair genes BRCA1 and BRCA2 are of unknown impact on protein function or clinical relevance, referred to as unclassified variants (UCV). Lymphocytes from pathogenic BRCA1/2 mutation carriers exhibit an increased level of chromosomal damage after irradiation. We established a radiation assay for the discrimination of pathogenic BRCA2 variants versus controls based on the level of chromosomal damage upon irradiation (p < 0.001). As a consequence, lymphocytes from UCV carriers could be separated into two distinct groups with normal or diminished DNA double strand break repair capacity. Our results suggested that all five UCV tested were benign and that one family carried a putative mutation in an as yet undetected DNA-repair gene. Thus, our test may serve as a valuable tool that aids the classification of BRCA2 UCV, but very likely also of BRCA1 UCV or aberrations in other genes involved in the DNA-repair system.
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Proteína BRCA2/genética , Neoplasias da Mama/genética , Quebra Cromossômica , Cromossomos Humanos/efeitos da radiação , Genes BRCA2 , Quebras de DNA de Cadeia Dupla , Reparo do DNA/genética , Feminino , Heterozigoto , Humanos , Pessoa de Meia-Idade , Mutação , Tolerância a Radiação/genética , Raios UltravioletaRESUMO
Multiple sclerosis (MS) is a neurological condition associated with a wide variety of physical, cognitive, and mood-related symptoms. While disease-modifying treatment has been shown to reduce the severity and frequency of MS symptom relapses, engagement in certain daily activities holds promise as an adjunctive treatment to better manage disease sequelae. The present study sought to determine whether healthy nutritional choices, exercise, and social/intellectual engagement impacts functioning in individuals with MS. Two hundred and forty-eight (248) MS participants completed a questionnaire assessing factors related to cognitive health (Cognitive Health Questionnaire; CHQ). They also endorsed measures assessing disease symptoms and management, mood, and well-being/quality of life. A measure of information processing speed was administered to a subset of participants. Findings indicated that a previously derived CHQ factor comprised of healthy nutritional habits and exercise items was associated with less fatigue, better sleep, reduced pain, and improved mood and disease management. A factor with items assessing social and intellectual engagement correlated with mood, disease management, and well-being. Endorsement of items in both CHQ factors was associated with better information processing speed. Subsequent regression analyses indicated that education and mood were most predictive of nutritional habits and exercise, while MS self-efficacy was particularly associated with engagement in social and intellectual activities. In sum, these findings suggest that self-reported engagement in healthy lifestyle habits has far-reaching effects on multiple aspects of daily living and disease management in MS.
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Transtornos Cognitivos/etiologia , Estilo de Vida , Transtornos do Humor/etiologia , Esclerose Múltipla/complicações , Esclerose Múltipla/psicologia , Qualidade de Vida/psicologia , Adulto , Transtornos Cognitivos/diagnóstico , Progressão da Doença , Fadiga/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sistemas On-Line , Escalas de Graduação Psiquiátrica , Transtornos do Sono-Vigília/diagnóstico , Transtornos do Sono-Vigília/etiologia , Inquéritos e Questionários , Adulto JovemRESUMO
We studied the dynamic behavior of human hematopoietic stem cells (HSC) on the in vitro model of bone marrow surfaces in the absence and presence of chemokine (SDF1α). The deformation and migration of cells were investigated by varying the chemokine concentration and surface density of ligand molecules. Since HSC used in this study were primary cells extracted from the human umbilical cord blood, it is not possible to introduce molecular reporter systems before or during the live cell imaging. To account for the experimental observations, we propose a simple and general theoretical model for cell crawling. In contrast to other theoretical models reported previously, our model focuses on the nonlinear coupling between shape deformation and translational motion and is free from any molecular-level process. Therefore, it is ideally suited for the comparison with our experimental results. We have demonstrated that the results in the absence of SDF1α were well recapitulated by the linear model, while the nonlinear model is necessary to reproduce the elongated migration observed in the presence of SDF1α. The combination of the simple theoretical model and the label-free, live cell observations of human primary cells opens a large potential to numerically identify the differential effects of extrinsic factors such as chemokines, growth factors, and clinical drugs on dynamic phenotypes of primary cells.
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Forma Celular/fisiologia , Quimiocina CXCL12/metabolismo , Células-Tronco Hematopoéticas/fisiologia , Modelos Biológicos , Movimento Celular/fisiologia , Células Cultivadas , Meios de Cultura/metabolismo , Sangue Fetal/citologia , Células-Tronco Hematopoéticas/citologia , Humanos , Microscopia Intravital , Modelos Lineares , Dinâmica não Linear , Cultura Primária de CélulasRESUMO
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
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Efficient mobilization of hematopoietic stem and progenitor cells (HSPC) is one of the most crucial issues for harvesting an adequate amount of peripheral HSPC for successful clinical transplantation. Applying well-defined surrogate models for the bone marrow niche, live cell imaging techniques, and novel tools in statistical physics, we have quantified the functionality of two mobilization agents that have been applied in the clinic, NOX-A12 and AMD3100 (plerixafor), as compared to a naturally occurring chemokine in the bone marrow, SDF1α. We found that NOX-A12, an L-enantiomeric RNA oligonucleotide to SDF1, significantly reduced the adhesion of HSPC to the niche surface mediated via the CXCR4-SDF1α axis, and stretched the migration trajectories of the HSPC. We found that the stretching of trajectories by NOX-A12 was more prominent than that by SDF1α. In contrast, plerixafor exhibited no detectable interference with adhesion and migration. We also found that the deformation of HSPC induced by SDF1α or plerixafor was also drastically suppressed in the presence of NOX-A12. This novel technology of quantitative assessment of "dynamic phenotypes" by physical tools has therefore enabled us to define different mechanisms of function for various extrinsic factors compared to naturally occurring chemokines.
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Quimiocina CXCL12/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco/metabolismo , Benzilaminas , Medula Óssea/efeitos dos fármacos , Medula Óssea/metabolismo , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Movimento Celular/efeitos dos fármacos , Células Cultivadas , Quimiocinas/metabolismo , Ciclamos , Mobilização de Células-Tronco Hematopoéticas/métodos , Células-Tronco Hematopoéticas/efeitos dos fármacos , Compostos Heterocíclicos/farmacologia , Humanos , Receptores CXCR4/metabolismo , Nicho de Células-Tronco/efeitos dos fármacos , Células-Tronco/efeitos dos fármacosRESUMO
OBJECTIVE: Weight loss maintenance is one of the biggest challenges in behavioral weight loss programs. The present study aimed to examine metabolic influences on the mesolimbic reward system in people with successful and unsuccessful long-term weight loss maintenance. METHODS: Thirty-three women with obesity at least 6 months after the completion of a diet were recruited: seventeen women were able to maintain their weight loss, whereas sixteen showed weight regain. Using functional magnetic resonance imaging in combination with the assessment of appetite-regulating hormones, neural reward processing during hunger and satiety was investigated. An incentive delay task was employed to investigate the expectation and receipt of both food-related and monetary reward. RESULTS: Only participants with successful weight loss maintenance showed a satiety-induced attenuation of brain activation during the receipt of a food-related reward. Furthermore, in successful weight loss maintenance, the attenuation of active ghrelin levels was related to brain activation in response to food-related reward anticipation during satiety. CONCLUSIONS: The findings suggest that an attenuated influence of satiety signaling on the neural processing of food-related reward contributes to unsuccessful weight loss maintenance. Thus, intact satiety signaling to the mesolimbic reward system may serve as a promising target for tackling weight cycling.
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Manutenção do Peso Corporal/fisiologia , Imageamento por Ressonância Magnética/métodos , Obesidade/fisiopatologia , Adulto , Feminino , Humanos , Masculino , RecompensaRESUMO
BACKGROUND: Heightened sensitivity towards reward and insensitivity towards disadvantageous consequences may constitute a driving factor underlying unrestricted food intake and consequent weight gain in people with overweight and obesity. Therefore, the present study applied a behavioral economics approach to investigate the potential contribution of poor reward-related decision making to unsuccessful long-term weight loss maintenance (i.e. weight cycling). Based on previous research, it was expected that successful long-term weight loss maintainers would show a better performance in a gambling task than their less successful counterparts. METHODS: Reward-related decision making was assessed post hoc using the Game of Dice Task in a total of 33 overweight and obese women who had either (a) successfully maintained initial weight loss of at least 10% of their body weight over one year or (b) had regained weight until at least their initial body weight prior to weight reduction (i.e. showed weight cycling). RESULTS: The groups did not differ in terms of age, current body weight, magnitude of initial weight reduction, educational level, and global intelligence level. As hypothesized, however, the group of successful long-term weight loss maintainers performed significantly better (i.e. showed less impulsive, more advantageous choices) in the Game of Dice Task than their less successful counterparts. CONCLUSIONS: The findings suggest that poor reward-related decision making is associated with weight cycling which is considered a key concern in weight loss treatments for overweight and obesity. Furthermore, the findings speak in favor of specific psychological interventions that are designed to bolster reward-related decision making.
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Tomada de Decisões , Obesidade/psicologia , Sobrepeso/psicologia , Recompensa , Redução de Peso , Adulto , Feminino , Jogo de Azar , Humanos , Adulto JovemRESUMO
Lensless, coherent X-ray diffraction microscopy has been drawing considerable attentions for tomographic imaging of whole human cells. In this study, we performed cryogenic coherent X-ray diffraction imaging of human erythrocytes with and without malaria infection. To shed light on structural features near the surface, "ghost cells" were prepared by the removal of cytoplasm. From two-dimensional images, we found that the surface of erythrocytes after 32 h of infection became much rougher compared to that of healthy, uninfected erythrocytes. The Gaussian roughness of an infected erythrocyte surface (69 nm) is about two times larger than that of an uninfected one (31 nm), reflecting the formation of protein knobs on infected erythrocyte surfaces. Three-dimensional tomography further enables to obtain images of the whole cells with no remarkable radiation damage, whose accuracy was estimated using phase retrieval transfer functions to be as good as 64 nm for uninfected and 80 nm for infected erythrocytes, respectively. Future improvements in phase retrieval algorithm, increase in degree of coherence, and higher flux in combination with complementary X-ray fluorescence are necessary to gain both structural and chemical details of mesoscopic architectures, such as cytoskeletons, membraneous structures, and protein complexes, in frozen hydrated human cells, especially under diseased states.
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Eritrócitos/patologia , Malária/diagnóstico por imagem , Malária/patologia , Microscopia/métodos , Tomografia por Raios X/métodos , Difração de Raios X/métodos , Células Cultivadas , Criopreservação , Eritrócitos/metabolismo , Humanos , Imageamento Tridimensional/métodos , Malária/metabolismo , Proteínas/metabolismo , Tomografia por Raios X/instrumentaçãoRESUMO
Whereas RAD51C mutations increase the relative risk for ovarian cancer (OC) to 5.88 (95% confidence interval=2.91-11.88, P=7.65×10), the associated risks for breast cancer (BC) remain largely unknown, as deleterious RAD51C alterations are extremely rare in BC-only families. Here, we report the results of a RAD51C mutational screening in a large series of German familial index patients negative for pathogenic BRCA1/2 mutations and the in-vitro characterization of two novel exonic RAD51C splice-site mutations. A total of 610 index cases derived from BC/OC (n=587) or OC-only families (n=23) were screened for potentially deleterious germline mutations in RAD51C. The frequencies of two splice-site mutations were assessed by single-nucleotide polymorphism genotyping in 1410 additional cases not enriched for OC family history. In three independent families, we identified novel splice-site mutations affecting the last nucleotide of exon 2 (c.404G>C, c.404G>T). Both mutations disrupt proper RAD51C pre-mRNA processing and cause a missense substitution immediately followed by a stop codon (p.Cys135Serfs*2; p.Cys135Leufs*2). Even though both mutations have similar effects on the protein level, they are associated with either BC/OC, OC-only, or BC-only family histories. The rare finding of a clearly truncating RAD51C mutation in an early-onset BC patient with a BC-only family history supports the notion that compromised RAD51C function may result in both BC and OC. Large international collaborative studies are needed to quantify the relative risk of RAD51C alterations for BC and to unravel the genetic modifying factors that determine phenotypic variability with respect to cancer site.