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Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is successful in patients with advanced Parkinson's disease (PD) but may worsen cognitive outcome, including facial emotion recognition (FER). Data-analyses on 59 consecutive PD patients with complete pre- and postoperative assessments, using a sensitive FER test, showed no changes in FER 1 year after STN-DBS surgery, both after group and individual analyses. These findings do however not exclude the impact of FER in and on itself on the outcome after STN-DBS.
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Estimulação Encefálica Profunda , Reconhecimento Facial , Doença de Parkinson , Núcleo Subtalâmico , Humanos , Doença de Parkinson/terapia , Doença de Parkinson/psicologia , Núcleo Subtalâmico/fisiologiaRESUMO
BACKGROUND: Alcoholic cerebellar degeneration is a restricted form of cerebellar degeneration, clinically leading to an ataxia of stance and gait and occurring in the context of alcohol misuse in combination with malnutrition and thiamine depletion. However, a similar degeneration may also develop after non-alcoholic malnutrition, but evidence for a lasting ataxia of stance and gait and lasting abnormalities in the cerebellum is lacking in the few patients described with purely nutritional cerebellar degeneration (NCD). METHODS: We present a case of a 46-year-old woman who developed NCD and Wernicke's encephalopathy (WE) due to COVID-19 and protracted vomiting, resulting in thiamine depletion. We present her clinical course over the first 6 months after the diagnosis of NCD and WE, with thorough neuropsychological and neurological examinations, standardized clinical observations, laboratory investigations, and repeated MRIs. RESULTS: We found a persistent ataxia of stance and gait and evidence for an irreversible restricted cerebellar degeneration. However, the initial cognitive impairments resolved. CONCLUSIONS: Our study shows that NCD without involvement of alcohol neurotoxicity and with a characteristic ataxia of stance and gait exists and may be irreversible. We did not find any evidence for lasting cognitive abnormalities or a cerebellar cognitive-affective syndrome (CCAS) in this patient.
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Although titanium dioxide (TiO2) is a suspected human carcinogen when inhaled, fiber-grade TiO2 (nano)particles were demonstrated in synthetic textile fibers of face masks intended for the general public. STEM-EDX analysis on sections of a variety of single use and reusable face masks visualized agglomerated near-spherical TiO2 particles in non-woven fabrics, polyester, polyamide and bi-component fibers. Median sizes of constituent particles ranged from 89 to 184 nm, implying an important fraction of nano-sized particles (< 100 nm). The total TiO2 mass determined by ICP-OES ranged from 791 to 152,345 µg per mask. The estimated TiO2 mass at the fiber surface ranged from 17 to 4394 µg, and systematically exceeded the acceptable exposure level to TiO2 by inhalation (3.6 µg), determined based on a scenario where face masks are worn intensively. No assumptions were made about the likelihood of the release of TiO2 particles itself, since direct measurement of release and inhalation uptake when face masks are worn could not be assessed. The importance of wearing face masks against COVID-19 is unquestionable. Even so, these results urge for in depth research of (nano)technology applications in textiles to avoid possible future consequences caused by a poorly regulated use and to implement regulatory standards phasing out or limiting the amount of TiO2 particles, following the safe-by-design principle.
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Máscaras , Espectrofotometria Atômica , Titânio/análise , COVID-19/prevenção & controle , COVID-19/virologia , Humanos , Exposição por Inalação/análise , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , SARS-CoV-2/isolamento & purificação , Controle Social Formal , Têxteis/análiseRESUMO
Purpose This systematic review focuses on the effect of bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) on language function in Parkinson's disease (PD). It fills an important gap in recent reviews by considering other language tasks in addition to verbal fluency. Method We critically and systematically reviewed the literature on studies that investigated the effect of bilateral STN-DBS on language function in PD. All studies included a matched PD control group who were on best medical treatment, with language testing at similar baseline and follow-up intervals as the DBS PD group. Results Thirteen identified studies included a form of a verbal fluency task, seven studies included picture naming, and only two studies included more language-oriented tasks. We found that verbal fluency was negatively affected after DBS, whereas picture naming was unaffected. Studies investigating individual change patterns using reliable change indices showed that individual variability is larger for picture naming than for verbal fluency. Conclusions Verbal fluency is the most frequently investigated aspect of language function. Our analysis showed a pattern of decline in verbal fluency across multiple studies after STN-DBS, whereas picture naming was unaffected. Data on more language-oriented tests in a large DBS sample and best medical treatment control group are sparse. The investigation of language function in PD after DBS requires sensitive language tests (with and without time pressure) and experimental designs as used in the studies reviewed here. Reliable change index statistics are a promising tool for investigating individual differences in performance after DBS. Supplemental Material https://doi.org/10.23641/asha.14794458.
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Estimulação Encefálica Profunda , Doença de Parkinson , Núcleo Subtalâmico , Humanos , Idioma , Testes de Linguagem , Doença de Parkinson/terapiaRESUMO
Silver (E174) is authorised as a food additive in the EU. The unknown particle size distribution of E174 is a specific concern for the E174 risk assessment. This study characterised the fraction of silver (nano)particles in 10 commercially available pristine E174 food additives and 10 E174-containing products by transmission electron microscopy (TEM) and single-particle inductively coupled plasma-mass spectrometry (spICP-MS). TEM analysis showed that all samples contained micrometre-sized flakes and also a fraction of (nano)particles. Energy-dispersive X-ray spectroscopy (EDX) and electron diffraction confirmed that the (nano)particles and micrometre-sized flakes consisted of silver. A higher amount of (nano)particles was observed in the products than in the food additives. In addition, the surface of the micrometre-sized flakes was rougher in products. The median of the minimum external dimension, assessed as minimal Feret diameter, of the fraction of (nano)particles determined by quantitative TEM analysis was 11 ± 4 nm and 18 ± 7 nm (overall mean ± standard deviation), for food additives and products, respectively. Similar size distributions were obtained by spICP-MS and TEM, considering the limit of detection of spICP-MS. The median of the equivalent spherical diameter of the fraction of (nano)particles determined by spICP-MS was 19 ± 4 nm and 21 ± 2 nm (overall mean ± standard deviation), for food additives and products, respectively. In all samples, independent of the choice of technique, the nano-sized particles represented more than 97% (by number) of the silver particles, even though the largest mass of silver was present as flakes.
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Aditivos Alimentares/química , Nanopartículas Metálicas/química , Prata/química , Acetona/química , Doces , Espectrometria de Massas , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Povidona/química , Medição de Risco , Cloreto de Sódio/químicaRESUMO
E171 (titanium dioxide) is a food additive that has been authorized for use as a food colorant in the European Union. The application of E171 in food has become an issue of debate, since there are indications that it may alter the intestinal barrier. This work applied standardized and validated methodologies to characterize representative samples of 15 pristine E171 materials based on transmission electron microscopy (TEM) and single-particle inductively coupled plasma mass spectrometry (spICP-MS). The evaluation of selected sample preparation protocols allowed identifying and optimizing the critical factors that determine the measurement of the particle size distribution by TEM. By combining optimized sample preparation with method validation, a significant variation in the particle size and shape distributions, the crystallographic structure (rutile versus anatase), and the physicochemical form (pearlescent pigments versus anatase and rutile E171) was demonstrated among the representative samples. These results are important for risk assessment of the E171 food additive and can contribute to the implementation of the European Food Safety Authority (EFSA) guidance on risk assessment of the application of nanoscience and nanotechnologies in the food and feed chain.
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E174 (silver) is a food additive that may contain silver nanoparticles (AgNP). Validated methods are needed to size and quantify these particles in a regulatory context. However, no validations have yet been performed with food additives or real samples containing food additives requiring a sample preparation step prior to analysis. A single-particle inductively coupled plasma mass spectrometry (spICP-MS) method was developed and validated for sizing and quantifying the fraction of AgNP in E174 and in products containing E174, and associated uncertainties related to sample preparation, analysis and data interpretation were unraveled. The expanded measurement uncertainty for AgNP sizing was calculated to be 16% in E174-containing food products and increased up to 23% in E174 itself. The E174 food additives showed a large silver background concentration combined with a relatively low number of nanoparticles, making data interpretation more challenging than in the products. The standard uncertainties related to sample preparation, analysis, and challenging data interpretation were respectively 4.7%, 6.5%, and 6.0% for triplicate performances. For a single replicate sample, the uncertainty related to sample preparation increased to 6.8%. The expanded measurement uncertainty related to the concentration determination was 25-45% in these complex samples, without a clear distinction between additives and products. Overall, the validation parameters obtained for spICP-MS seem to be fit for the purpose of characterizing AgNP in E174 or E174-containing products.
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OBJECTIVE: We report the case of a professional violin player who underwent an awake craniotomy to resect a tumor in the left supplementary motor area, an area involved in motor planning. METHOD: A careful pre- and intraoperative monitoring plan for music performance and complex motor function was established that could be used in combination with cortical stimulation. RESULTS: The patient suffered an epileptic seizure during cortical stimulation. The monitoring of complex motor and musical functions was implemented with the patient playing the violin while the resection was performed. Almost complete resection was achieved with no notable postoperative deficits contributing to functional impairment. CONCLUSIONS: The multidisciplinary approach, involving neurosurgery, neuropsychology, anesthesiology, and clinical neurophysiology, allowed us to successfully cope with the theoretical and practical challenges associated with tailored care for a professional musician. The music and motor monitoring plan is reported in detail to enable other sites to reproduce and adapt it accordingly.
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Neoplasias Encefálicas/cirurgia , Craniotomia/métodos , Monitorização Intraoperatória/métodos , Córtex Motor/cirurgia , Música , Vigília/fisiologia , Adulto , Mapeamento Encefálico , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/fisiopatologia , Humanos , Masculino , Córtex Motor/patologia , Córtex Motor/fisiopatologia , Testes Neuropsicológicos , Resultado do TratamentoRESUMO
BACKGROUND/AIMS: Ligating the right lateral vitelline vein of chicken embryos (venous clip) results in cardiovascular malformations. These abnormalities are similar to malformations observed in knockout mice studies of components of the endothelin-1 (ET-1)/endothelin-converting enzyme-1/endothelin-A receptor pathway. In previous studies we demonstrated that cardiac ET-1 expression is decreased 3 h after clipping, and ventricular diastolic filling is disturbed after 2 days. Therefore, we hypothesise that ET-1-related processes are involved in the development of functional and morphological cardiovascular defects after venous clip. METHODS: In this study, ET-1 and endothelin receptor antagonists (BQ-123, BQ-788 and PD145065) were infused into the HH18 embryonic circulation. Immediate haemodynamic effects on the embryonic heart and extra-embryonic vitelline veins were examined by Doppler and micro-particle image velocimetry. Ventricular diastolic filling characteristics were studied at HH24, followed by cardiovascular morphologic investigation (HH35). RESULTS: ET-1 and its receptor antagonists induced haemodynamic effects at HH18. At HH24, a reduced diastolic ventricular passive filling component was demonstrated, which was compensated by an increased active filling component. Thinner ventricular myocardium was shown in 42% of experimental embryos. CONCLUSION: We conclude that cardiovascular malformations after venous clipping arise from a combination of haemodynamic changes and altered gene expression patterns and levels, including those of the endothelin pathway.
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Anormalidades Cardiovasculares/metabolismo , Endotelina-1/metabolismo , Coração/fisiopatologia , Hemodinâmica , Miocárdio/metabolismo , Receptores de Endotelina/metabolismo , Transdução de Sinais , Saco Vitelino/irrigação sanguínea , Animais , Ácido Aspártico Endopeptidases/genética , Ácido Aspártico Endopeptidases/metabolismo , Velocidade do Fluxo Sanguíneo , Débito Cardíaco , Anormalidades Cardiovasculares/genética , Anormalidades Cardiovasculares/patologia , Anormalidades Cardiovasculares/fisiopatologia , Células Cultivadas , Embrião de Galinha , Ecocardiografia , Antagonistas dos Receptores de Endotelina , Endotelina-1/genética , Enzimas Conversoras de Endotelina , Regulação da Expressão Gênica no Desenvolvimento , Coração/embriologia , Frequência Cardíaca , Hemodinâmica/efeitos dos fármacos , Fluxometria por Laser-Doppler , Ligadura , Metaloendopeptidases/genética , Metaloendopeptidases/metabolismo , Miocárdio/patologia , Oligopeptídeos/farmacologia , Peptídeos Cíclicos/farmacologia , Piperidinas/farmacologia , RNA Mensageiro/metabolismo , Receptores de Endotelina/genética , Transdução de Sinais/efeitos dos fármacos , Fatores de Tempo , Veias/fisiopatologia , Veias/cirurgia , Função VentricularRESUMO
Patients with multiple sclerosis (MS) often suffer from psychological distress and cognitive dysfunctioning. These factors negatively impact the health-related quality of life. Only recently behavioral therapeutic approaches are being used to treat psychological distress in MS. The aim of the present pilot study was not only to investigate the effectiveness of mindfulness-based stress reduction (MBSR) on psychological distress but also to explore whether it can improve cognitive functioning among patients with MS. Outpatients of the MS Center of the Radboud University Medical Center (Radboudumc) were invited to participate in an MBSR training. Psychological and cognitive measures were administered pre- and post-intervention. Twenty-five MS patients completed the MBSR training and psychological measures, of which 16 patients completed the cognitive tests. Significant improvements were found in depressive symptoms, quality of life, fatigue, mindfulness skills, and self-compassion. Of the cognitive tests, performance on a visual spatial processing test significantly improved after the intervention. Overall, this pilot study showed promising results of the effects of MBSR on reducing psychological distress, and it suggests MBSR might improve cognitive functioning in MS patients. Future randomized controlled trials should be conducted to confirm the possible effectiveness of MBSR-and its long-term effects-on psychological and cognitive functioning in MS patients.
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Autosomal dominant centronuclear myopathy (CNM) caused by mutations in the gene coding for amphiphysin-2 (BIN1) typically presents in adulthood with progressive muscle weakness. We report a Dutch family with AD CNM due to a novel BIN1 mutation (c.53T>A (p.Val18Glu)), strongly impairing the membrane tubulation activity of amphiphysin-2. The main features were mild proximal weakness with pronounced myalgia, exercise intolerance and large muscle mass, with a childhood onset in the youngest generation and mild cognitive features. This suggests BIN1 mutations should be considered in patients with isolated exercise intolerance and myalgia, even in childhood.
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Proteínas Adaptadoras de Transdução de Sinal/genética , Mutação , Miopatias Congênitas Estruturais/genética , Proteínas Nucleares/genética , Proteínas Supressoras de Tumor/genética , Idade de Início , Idoso , Criança , Família , Feminino , Genes Dominantes , Humanos , Masculino , Pessoa de Meia-Idade , Miopatias Congênitas Estruturais/epidemiologia , Miopatias Congênitas Estruturais/patologia , FenótipoRESUMO
The measurement of blood-plasma velocity distributions with spatial and temporal resolution in vivo is inevitable for the determination of shear stress distributions in complex geometries at unsteady flow conditions like in the beating heart. A non-intrusive, whole-field velocity measurement technique is required that is capable of measuring instantaneous flow fields at sub-millimeter scales in highly unsteady flows. Micro particle image velocimetry (muPIV) meets these demands, but requires special consideration and methodologies in order to be utilized for in vivo studies in medical and biological research. We adapt muPIV to measure the blood-plasma velocity in the beating heart of a chicken embryo. In the current work, bio-inert, fluorescent liposomes with a nominal diameter of 400 nm are added to the flow as a tracer. Because of their small dimension and neutral buoyancy the liposomes closely follow the movement of the blood-plasma and allow the determination of the velocity gradient close to the wall. The measurements quantitatively resolve the velocity distribution in the developing ventricle and atrium of the embryo at nine different stages within the cardiac cycle. Up to 400 velocity vectors per measurement give detailed insight into the fluid dynamics of the primitive beating heart. A rapid peristaltic contraction accelerates the flow to peak velocities of 26 mm/s, with the velocity distribution showing a distinct asymmetrical profile in the highly curved section of the outflow tract. In relation to earlier published gene-expression experiments, the results underline the significance of fluid forces for embryonic cardiogenesis. In general, the measurements demonstrate that muPIV has the potential to develop into a general tool for instationary flow conditions in complex flow geometries encountered in cardiovascular research.
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Velocidade do Fluxo Sanguíneo/fisiologia , Circulação Coronária/fisiologia , Coração/embriologia , Coração/fisiologia , Hemorreologia/métodos , Interpretação de Imagem Assistida por Computador/métodos , Microscopia de Fluorescência/métodos , Animais , Embrião de Galinha , Galinhas , MicroesferasRESUMO
The study investigated the influence of a syntactically biasing context sentence on the processing of syntactically complex object-first relative clauses and even more complex object-first complement clauses in readers with individual differences in working memory. Behavioral as well as brain responses (event-related potentials, ERPs) were recorded from two groups of participants with either a high or a low working memory span. The behavioral data taken from a post-sentence comprehension question task indicate an intersentential syntactic contextual influence on the comprehension of object-first relative clauses for low span readers, but not for high span readers. The on-line ERP measures taken at the disambiguating item revealed for the high span readers a main effect of structure (subject- versus object-first) i.e., a P600, independent of context. Low span readers, in contrast, did not show any P600 structure effect. Thus, the combined data indicate a differential context effect on sentence comprehension in low and high span readers. High span readers parse the incoming information independent of intersentential context, whereas low span readers use the intersentential context off-line.
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Idioma , Linguística , Memória de Curto Prazo , Adulto , Potenciais Evocados/fisiologia , Feminino , Humanos , Testes de Linguagem , Masculino , Leitura , Semântica , Aprendizagem Verbal/classificação , Aprendizagem Verbal/fisiologiaRESUMO
PROBLEM: People with mental illness are twice as likely to smoke than people without a mental illness. METHODS: Data were collected through interviews with individuals who smoke and have been diagnosed with schizophrenia (N = 100). The research design included a descriptive, correlational design that described and examined the relationships among psychiatric symptoms, medication side effects, and reasons for smoking; and a qualitative analysis of the subjective experience of smoking. FINDINGS: A positive relationship was found between the age of onset of smoking and the onset of schizophrenia. Subjects reported they smoked primarily for sedative effects and control of negative symptoms of schizophrenia. Subjects also reported smoking related to addiction. Most indicated they would like to quit smoking or at least cut down on the number of cigarettes. CONCLUSIONS: Among people with schizophrenia, the motivation to smoke is related to their schizophrenia.
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Psicologia do Esquizofrênico , Fumar/psicologia , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Motivação , Ontário , Fatores de Risco , Fumar/fisiopatologia , Prevenção do Hábito de FumarRESUMO
The expression of memory worries and the self-reporting of daily forgetfulness easily spark discussion among sufferers and their family or friends about what is normal or abnormal forgetfulness. One way to investigate whether the reporting of forgetfulness might be excessive is to use a standardized memory questionnaire--for instance, the Multifactorial Memory Questionnaire (MMQ). The MMQ measures worries, daily forgetfulness, and memory strategy use. In this study we present a psychometric evaluation of the Dutch translation of the MMQ and provide normative data to determine the significance of individual differences in subtest scores. In addition, clinical examples are given of the use and interpretation of percentile norms and single-case statistics.
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Transtornos da Memória/diagnóstico , Transtornos da Memória/psicologia , Psicometria/métodos , Autorrelato , Inquéritos e Questionários , Traduções , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Fatores Sexuais , Adulto JovemRESUMO
The purpose of this qualitative, descriptive study was to explore the perspectives of individuals who were caring for a family member with a mental illness, with particular attention to housing, quality of supports, and formal care services. Eleven focus groups with family caregivers (N = 75) were conducted. Both individual and team thematic analyses were undertaken until interpretations of the experiences of the participants were inductively developed and conceptualized into a holistic interpretation. Findings revealed that family caregivers were part of a "circle of care," supporting the independence of the individual with mental illness while attempting to protect their family member with mental illness. However, findings suggested that this circle of care led to a "vicious cycle" of caregiving. Three major themes were identified: witnessing inadequacies, working behind the scenes, and creating a better world. Health-promoting family nursing practice and policy implications, as well as areas for further research, are discussed.
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Atitude Frente a Saúde , Cuidadores/psicologia , Transtornos Mentais/terapia , Serviços de Saúde Mental , Qualidade da Assistência à Saúde , Adulto , Filhos Adultos , Canadá , Emoções , Feminino , Grupos Focais , Habitação , Humanos , Masculino , Pessoa de Meia-Idade , Apoio SocialRESUMO
Cardiac pressure-volume relations enable quantification of intrinsic ventricular diastolic and systolic properties independent of loading conditions. The use of pressure-volume loop analysis in early stages of development could contribute to a better understanding of the relationship between hemodynamics and cardiac morphogenesis. The venous clip model is an intervention model for the chick embryo in which permanent obstruction of the right lateral vitelline vein temporarily reduces the mechanical load on the embryonic myocardium and induces a spectrum of outflow tract anomalies. We used pressure-volume loop analysis of the embryonic chick heart at stage 21 (3.5 d of incubation) to investigate whether the development of ventricular function is affected by venous clipping at stage 17, compared with normal control embryos. Steady state hemodynamic parameters demonstrated no significant differences between the venous clipped and control embryos. However, analysis of pressure-volume relations showed a significantly lower end-systolic elastance in the clipped embryos (slope of the end-systolic pressure-volume relation: 5.68 +/- 0.85 versus 11.76 +/- 2.70 mm Hg/microL, p < 0.05), indicating reduced contractility. Diastolic stiffness tended to be increased in the clipped embryos (slope of end-diastolic pressure-volume relation: 2.74 +/- 0.56 versus 1.67 +/- 0.21, p = 0.103), but the difference did not reach statistical significance. The results of the pressure-volume loop analysis show that 1 d after venous obstruction, development of ventricular function is affected, with reduced contractility. Pressure-volume analysis may be applied in the chick embryo and is a sensitive technique to detect subtle alterations in ventricular function.
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Pressão Sanguínea/fisiologia , Embrião não Mamífero/fisiologia , Função Ventricular , Animais , Volume Cardíaco , Embrião de Galinha , Diástole , Hemodinâmica/efeitos dos fármacos , Modelos Anatômicos , Volume Sistólico , Sístole , Fatores de TempoRESUMO
Syntactically ambiguous sentences have been found to be difficult to process, in particular, for individuals with low working memory capacity. The current study used fMRI to investigate the neural basis of this effect in the processing of written sentences. Participants with high and low working memory capacity read sentences with either a short or long region of temporary syntactic ambiguity while being scanned. A distributed left-dominant network in the peri-sylvian region was identified to support sentence processing in the critical region of the sentence. Within this network, only the superior portion of Broca's area (BA 44) and a parietal region showed an activation increase as a function of the length of the syntactically ambiguous region in the sentence. Furthermore, it was only the BA 44 region that exhibited an interaction of working memory span, length of the syntactic ambiguity, and sentence complexity. In this area, the activation increase for syntactically more complex sentences became only significant under longer regions of ambiguity, and for low span readers only. This finding suggests that neural activity in BA 44 increases during sentence comprehension when processing demands increase, be it due to syntactic processing demands or by an interaction with the individually available working memory capacity.
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Mapeamento Encefálico , Córtex Cerebral/fisiologia , Memória de Curto Prazo/fisiologia , Leitura , Semântica , Adulto , Dominância Cerebral/fisiologia , Humanos , Idioma , Testes de Linguagem , Imageamento por Ressonância Magnética , Valores de Referência , Fatores de Tempo , Comportamento Verbal/fisiologiaRESUMO
Alteration of extra-embryonic venous blood flow in stage-17 chick embryos results in well-defined cardiovascular malformations. We hypothesize that the decreased dorsal aortic blood volume flow observed after venous obstruction results in altered ventricular diastolic function in stage-24 chick embryos. A microclip was placed at the right lateral vitelline vein in a stage-17 (52-64 h of incubation) chick embryo. At stage 24 (4.5 days of incubation), we measured simultaneously dorsal aortic and atrioventricular blood flow velocities with a 20-MHz pulsed-Doppler velocity meter. The fraction of passive and active filling was integrated and multiplied by dorsal aortic blood flow to obtain the relative passive and active ventricular filling volumes. Data were summarized as means +/- S.E.M. and analyzed by t-test. At similar cycle lengths ranging from 557 ms to 635 ms (P>0.60), dorsal aortic blood flow and stroke volume measured in the dorsal aorta were similar in stage-24 clipped and normal embryos. Passive filling volume (0.07+/-0.01 mm(3)) was decreased, and active filling volume (0.40+/-0.02 mm(3)) was increased in the clipped embryo when compared with the normal embryo (0.15+/-0.01 mm(3), 0.30+/-0.01 mm(3), respectively) (P<0.003). In the clipped embryos, the passive/active ratio was decreased compared with that in normal embryos (P<0.001). Ventricular filling components changed after partially obstructing the extra-embryonic venous circulation. These results suggest that material properties of the embryonic ventricle are modified after temporarily reduced hemodynamic load.
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Aorta/fisiologia , Diástole/fisiologia , Coração/embriologia , Função Ventricular/fisiologia , Animais , Velocidade do Fluxo Sanguíneo , Embrião de Galinha , Coração/fisiologia , Ventrículos do Coração/anormalidades , Fluxo Sanguíneo Regional , Volume SistólicoRESUMO
In the venous clip model specific cardiac malformations are induced in the chick embryo by obstructing the right lateral vitelline vein with a microclip. Clipping alters venous return and intracardiac laminar blood flow patterns, with secondary effects on the mechanical load of the embryonic myocardium. We investigated the instantaneous effects of clipping the right lateral vitelline vein on hemodynamics in the stage-17 chick embryo. 32 chick embryos HH 17 were subdivided into venous clipped (N=16) and matched control embryos (N=16). Dorsal aortic blood flow velocity was measured with a 20 MHz pulsed Doppler meter. A time series of eight successive measurements per embryo was made starting just before clipping and ending 5h after clipping. Heart rate, peak systolic velocity, time-averaged velocity, peak blood flow, mean blood flow, peak acceleration and stroke volume were determined. All hemodynamic parameters decreased acutely after venous clipping and only three out of seven parameters (heart rate, time-averaged velocity and mean blood flow) showed a recovery to baseline values during the 5h study period. We conclude that the experimental alteration of venous return has major acute effects on hemodynamics in the chick embryo. These effects may be responsible for the observed cardiac malformations after clipping.