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1.
Br J Cancer ; 130(10): 1679-1686, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38575731

RESUMO

BACKGROUND: Tepotinib, a MET inhibitor approved for the treatment of MET exon 14 (METex14) skipping NSCLC, demonstrated durable clinical activity in VISION (Cohort A + C; N = 313): objective response rate (ORR) 51.4% (95% CI: 45.8, 57.1); median duration of response (mDOR) 18.0 months (95% CI: 12.4, 46.4). We report outcomes in Asian patients from VISION (Cohort A + C) (cut-off: November 20, 2022). METHODS: Patients with advanced METex14 skipping NSCLC, detected by liquid or tissue biopsy, received tepotinib 500 mg (450 mg active moiety) once daily. PRIMARY ENDPOINT: objective response (RECIST 1.1) by independent review. Secondary endpoints included: DOR, progression-free survival (PFS), overall survival (OS), safety, and health-related quality of life (HRQoL). RESULTS: Across treatment lines in 106 Asian patients (39.6% female, 43.4% smoking history, 79.2% adenocarcinoma, 47.2% treatment-naive), ORR was 56.6% (95% CI: 46.6, 66.2), mDOR 18.5 months (10.4, ne), mPFS 13.8 months (10.8, 22.0), and mOS 25.5 months (19.3, 36.4). Consistent efficacy observed, regardless of baseline characteristics. HRQoL remained stable during treatment. Treatment-related adverse events (TRAEs) occurred in 95.3% of patients (39.6% Grade ≥3). Most common TRAEs: peripheral edema (62.3%), creatinine increase (38.7%). CONCLUSIONS: Tepotinib demonstrated robust and durable efficacy, with a manageable safety profile, in Asian patients with METex14 skipping NSCLC. CLINICAL TRIAL REGISTRATION: NCT02864992.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Éxons , Neoplasias Pulmonares , Proteínas Proto-Oncogênicas c-met , Humanos , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Feminino , Masculino , Pessoa de Meia-Idade , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Idoso , Proteínas Proto-Oncogênicas c-met/genética , Adulto , Qualidade de Vida , Idoso de 80 Anos ou mais , Povo Asiático/genética , Pirimidinas/uso terapêutico , Pirimidinas/efeitos adversos , Intervalo Livre de Progressão , Piperidinas , Piridazinas
2.
J Therm Biol ; 114: 103499, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37344010

RESUMO

The Arctic has a diverse terrestrial microarthropod fauna which overwinters in situ in soil and vegetation. This fauna is involved in key ecosystem processes, for example decomposition and pollination, and has tolerance to the Arctic's winter conditions. However, the Arctic is undergoing rapid change. Svalbard is experiencing warming rates up to four times the global average as well as alterations in precipitation (quantity and form; snow or rain) and wind direction. These will modify the conditions experienced by the overwintering fauna. Since laboratory experiments often fail to capture the diversity of environmental stressors, we employed a manipulation experiment using the naturally accumulating snow pack to moderate soil winter soil temperatures, combined with an extended incubator treatment, to map the duration limits of naturally induced cold tolerance. We demonstrate that the Collembola fauna can tolerate temperatures of -25 °C but that, in areas devoid of snow accumulation and when soil temperatures dip below -30 °C there is significant mortality. Furthermore, we demonstrate that exposure to a further extended 12 month period at -6 °C, as a simple model of a situation where snow cover is not lost during the short Arctic summer, results in additional mortality with relatively few Collembola surviving. By contrast, while oribatid mites displayed similar survival over a natural winter as the Collembola, they were highly resistant to the extended exposure at -6 °C, with no additional mortality occurring. We also documented survival amongst other invertebrate groups, including Nematocera and Brachycera larvae, Hemiptera (Acyrthosiphon svalbardicum), Coleoptera (Isochnus flagellum), and Araneae (Linyphiidae). We conclude that snow depth and winter air temperatures interact to regulate soil microarthropod populations over local scales and therefore the functioning of the Arctic soil ecosystem. Moreover, the environmental changes currently being observed in polar regions will continue to modify this fauna and its local and micro-scale distribution.


Assuntos
Artrópodes , Ecossistema , Animais , Temperatura , Estações do Ano , Invertebrados , Regiões Árticas , Solo , Neve , Mudança Climática
3.
Brain Cogn ; 131: 10-21, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30502227

RESUMO

BACKGROUND: Functional connectivity (fcMRI) analyses of resting state functional magnetic resonance imaging (fMRI) data revealed substantial differences between states of consciousness. The underlying cause-effect linkage, however, remains unknown to the present day. The aim of this study was to examine the relationship between fcMRI measures and Disorders of Consciousness (DOC) in resting state and under adequate stimulation. METHODS AND FINDINGS: fMRI data from thirteen patients with unresponsive wakefulness syndrome, eight patients in minimally conscious state, and eleven healthy controls were acquired in rest and during the application of nociceptive and emotional acoustic stimuli. We compared spatial characteristics and anatomical topography of seed-based fcMRI networks on group and individual levels. The anatomical topography of fcMRI networks of patients was altered in all three conditions as compared with healthy controls. Spread and distribution of individual fcMRI networks, however, differed significantly between patients and healthy controls in stimulation conditions only. The exploration of individual metric values identified two patients whose spatial metrics did not deviate from metric distributions of healthy controls in a statistically meaningful manner. CONCLUSIONS: These findings suggest that the disturbance of consciousness in DOC is related to deficits in global topographical network organization rather than a principal inability to establish long-distance connections. In addition, the results question the claim that task-free measurements are particularly valuable as a tool for individual diagnostics in severe neurological disorders. Further studies comparing connectivity indices with outcome of DOC patients are needed to determine the clinical relevance of spatial metrics and stimulation paradigms for individual diagnosis, prognosis and treatment in DOC.


Assuntos
Encéfalo/diagnóstico por imagem , Transtornos da Consciência/diagnóstico por imagem , Estado de Consciência/fisiologia , Rede Nervosa/diagnóstico por imagem , Estimulação Acústica , Adolescente , Adulto , Idoso , Encéfalo/fisiopatologia , Transtornos da Consciência/fisiopatologia , Eletroencefalografia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Rede Nervosa/fisiopatologia , Descanso , Adulto Jovem
4.
Cogn Emot ; 30(2): 225-44, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25648386

RESUMO

Although several studies have examined inhibition of affective stimuli, valence-dependent cognitive control effects remain poorly understood. Behavioural and functional imaging (functional magnetic resonance imaging) data were collected from 17 healthy participants to examine neural correlates of the Negative Affective Priming (NAP) task. We created relative ratio scores considering the reaction times of prime trials in order to assess the amount of interference after the presentation of negative and positive distracter words. Behavioural results showed an attenuated NAP effect for negative distracters compared to neutral stimuli. Furthermore, priming negative distracters generated more interference by reacting to the probe target than positive distracters. Neuroimaging data revealed a stronger prefrontal activation during negative NAP trials compared to positive NAP and neutral control trials, which was reflected in a heightened activation of superior and middle frontal gyrus as well as parietal cortex. The findings show the impact of negative distracters on prefrontal response, contributing to the understanding of NAP effects in healthy subjects.


Assuntos
Afeto/fisiologia , Cognição/fisiologia , Córtex Pré-Frontal/fisiologia , Priming de Repetição/fisiologia , Adulto , Feminino , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Lobo Parietal/fisiologia , Estimulação Luminosa , Tempo de Reação/fisiologia , Adulto Jovem
5.
Hum Brain Mapp ; 35(4): 1297-304, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23450811

RESUMO

Sensory preconditioning (SPC; also known as behaviorally silent learning) consists of a combination of two neutral stimuli, none of which elicits an unconditional response. After one of them is later paired with an unconditional stimulus (US), the other neutral stimulus also yields a conditional response although it has never been paired with the US. In this study, an event-related functional magnetic resonance imaging (fMRI) paradigm was used to specify brain regions involved in SPC. The results demonstrated that SPC was associated with significant changes in activity of several regions, notably, the left amygdala, the left hippocampus, the bilateral thalamus, the bilateral medial globus pallidus, the bilateral cerebellum, the bilateral premotor cortex, and the bilateral middle frontal gyrus. This is a first effort to use fMRI to examine the effects of SPC on brain activation. Our data suggest that there is a distributed network of structures involved in SPC including both cortical and subcortical regions, therefore add to our understanding of the neural mechanisms underlying the ability to associative learning.


Assuntos
Aprendizagem por Associação/fisiologia , Percepção Auditiva/fisiologia , Encéfalo/fisiologia , Condicionamento Clássico/fisiologia , Percepção Visual/fisiologia , Estimulação Acústica , Adulto , Nível de Alerta , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Estimulação Luminosa , Adulto Jovem
6.
BMC Psychiatry ; 14: 210, 2014 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-25207861

RESUMO

BACKGROUND: Neuroticism is frequently discussed as a risk factor for psychopathology. According to the maturity principle, neuroticism decreases over the course of life, but not uniformly across individuals. However, the implications of differences in personality maturation on mental health have not been well studied so far. Hence, we hypothesized that different forms of neuroticism development from adolescence to young adulthood are associated with differences in depression, anxiety and everyday emotional experience at the age of 25. METHODS: A sample of 266 adolescents from the general population was examined three times over ten years (age at T0: 15, T1: 20 and T2: 25) using questionnaires, interviews and ecological momentary assessment (EMA). At all measurement points, neuroticism was assessed with the NEO inventory. At T2, diagnoses of major depression and anxiety disorders were captured with a structured clinical interview (M-CIDI). Phone-based EMA was used to assess emotional experience and affective instability over a two-week period at T2. RESULTS: The best fitting model was a latent class growth analysis with two groups of neuroticism development. Most individuals (n = 205) showed moderate values whereas 61 participants were clustered into a group with elevated neuroticism levels. In both groups neuroticism significantly changed during the ten year period with a peak at the age of 20. Individuals with a higher absolute level were at 14-fold increased risk for depression and 7-fold risk for anxiety disorders at the age of 25. In EMA, increased negative affect and arousal as well as decreased positive emotions were found in this high group. CONCLUSIONS: Other than expected, personality did not mature in our sample. However, there was a significant change of neuroticism values from adolescence to young adulthood. Further, over 20% of our participants showed a neuroticism development which was associated with adverse outcomes such as negatively toned emotional experience and a heightened risk to suffer from depressive and anxiety disorders in young adulthood. These high-risk persons need to be identified early to provide interventions supporting continuous personality maturation.


Assuntos
Transtornos de Ansiedade/psicologia , Ansiedade/psicologia , Depressão/psicologia , Emoções , Desenvolvimento da Personalidade , Personalidade , Adolescente , Adulto , Feminino , Humanos , Masculino , Saúde Mental , Neuroticismo , Inventário de Personalidade , Estudos Prospectivos , Inquéritos e Questionários , Adulto Jovem
7.
Brain Inj ; 28(9): 1156-63, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25099020

RESUMO

PRIMARY OBJECTIVE: A comparison between unitary and non-unitary views on minimal consciousness. RESEARCH DESIGN: First, unitary (all-or-none) and non-unitary (gradual or continuous) models of consciousness are defined as they have been developed in both philosophy and neurophysiology. Then, the implications of these ideas to the notion the minimally conscious state (MCS) are discussed. METHODS AND PROCEDURES: Review and analysis of theoretical conceptions and empirical data. MAIN OUTCOME AND RESULTS: Both kinds of models are compatible with the actual definitions of MCS. Although unitary views may seem to contradict the description of the MCS in 'Neurology' 2002, the apparent contradiction can easily be solved. Most recent data, particularly those obtained using fMRI and concerning learning, emotional responsiveness and pain and suffering, speak for non-unitary models. CONCLUSIONS: Most evidence speaks for non-unitary models of minimal consciousness. If these models are correct, patients with MCS may have, in addition to temporal fluctuations, a lower level of consciousness compared with fully conscious individuals. A still lower level could characterize patients diagnosed as unresponsive wakefulness syndrome (UWS). From this point of view, therefore, the difference between UWS and MCS is gradual rather than qualitative. However, due to methodological limitations of the available studies, the evidence for non-unitary models cannot be regarded as definite.


Assuntos
Encéfalo/fisiopatologia , Estado de Consciência , Estado Vegetativo Persistente/fisiopatologia , Estado de Consciência/classificação , Humanos , Imageamento por Ressonância Magnética , Modelos Teóricos , Estado Vegetativo Persistente/classificação , Filosofia , Prognóstico
8.
J Colloid Interface Sci ; 669: 32-42, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38703580

RESUMO

Simultaneously enhancing the durability and catalytic performance of metal-nitrogen-carbon (M-Nx-C) single-atom catalysts is critical to boost oxygen electrocatalysis for energy conversion and storage, yet it remains a grand challenge. Herein, through the combination of early and late metals, we proposed to enhance the stability and tune the catalytic activity of M-Nx-C SACs in oxygen electrocatalysis by their strong interaction with the M2'C-type MXene substrate. Our density functional theory (DFT) computations revealed that the strong interaction between "early-late" metal-metal bonds significantly improves thermal and electrochemical stability. Due to considerable charge transfer and shift of the d-band center, the electronic properties of these SACs can be extensively modified, thereby optimizing their adsorption strength with oxygenated intermediates and achieving eight promising bifunctional catalysts for ORR/OER with low overpotentials. More importantly, the constant-potential analysis demonstrated the excellent bifunctional activity of SACs supported on MXene substrate across a broad pH range, especially in strongly alkaline media with record-low overpotentials. Further machine learning analysis shows that the d-band center, the charge of the active site, and the work function of the formed heterojunctions are critical to revealing the ORR/OER activity origin. Our results underscore the vast potential of strong interactions between different metal species in enhancing the durability and catalytic performance of SACs.

9.
Plants (Basel) ; 13(5)2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38475481

RESUMO

The main aim of the present study has been the completion of genome size data for the diverse arctic-alpine A. ciliata species complex, with special focus on the unexplored arctic taxon A. pseudofrigida, the north-European A. norvegica, and A. gothica from Gotland (Sweden). Altogether, 46 individuals of these three Nordic taxa have been sampled from seven different regions and their genome size estimated using flow cytometry. Three other alpine taxa in the A. ciliata complex (A. multicaulis, A. ciliata subsp. ciliata, and A. ciliata subsp. bernensis) were also collected and analyzed for standardization purposes, comprising 20 individuals from six regions. A mean 2c value of 1.65 pg of DNA was recorded for A. pseudofrigida, 2.80 pg for A. norvegica, and 4.14 pg for A. gothica, as against the reconfirmed 2c value of 1.63 pg DNA for the type taxon A. ciliata subsp. ciliata. Our results presenting the first estimations of genome sizes for the newly sampled taxa, corroborate ploidy levels described in the available literature, with A. pseudofrigida being tetraploid (2n = 4x = 40), A. norvegica possessing predominantly 2n = 8x = 80, and A. gothica with 2n = 10x = 100. The present study also reconfirms genome size and ploidy level estimations published previously for the alpine members of this species complex. Reflecting a likely complex recent biogeographic history, the A. ciliata species group comprises a polyploid arctic-alpine species complex characterized by reticulate evolution, polyploidizations and hybridizations, probably associated with rapid latitudinal and altitudinal migrations in the Pleistocene-Holocene period.

10.
Arch Phys Med Rehabil ; 94(10): 1891-8, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23735520

RESUMO

OBJECTIVE: To determine the potential prognostic value of using functional magnetic resonance imaging (fMRI) to identify patients with disorders of consciousness, who show potential for recovery. DESIGN: Observational study. SETTING: Unit for acute rehabilitation care. PARTICIPANTS: Patients (N=22) in a vegetative state (VS; n=10) and minimally conscious state (MCS; n=12) during the first 200 days after the initial incident. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Further course on the Coma Recovery Scale-Revised. RESULTS: Participants performed a mental imagery fMRI paradigm. They were asked to alternately imagine playing tennis and navigating through their home. In 14 of the 22 examined patients (VS, n=5; MCS, n=9), a significant activation of the regions of interest (ROIs) of the mental imagery paradigm could be found. All 5 patients with activation of a significant blood oxygen level dependent signal, who were in a VS at the time of the fMRI examination, reached at least an MCS at the end of the observation period. In contrast, 5 participants in a VS who failed to show activation in ROIs, did not (sensitivity 100%, specificity 100%). Six of 9 patients in an MCS with activation in ROIs emerged from an MCS. Of 3 patients in an MCS who did not show activation, 2 patients stayed in an MCS and 1 patient emerged from the MCS (sensitivity 85%, specificity 40%). CONCLUSIONS: The fMRI paradigm mental imagery displays a high concordance with the further clinical course of patients in a VS. All 5 patients in a VS who showed significant activation of ROIs had a favorable further course until the end of the observation period. We therefore propose the term "functional minimally conscious state" for these patients. They may benefit from rehabilitation treatment. In cases where no significant activation was seen, the method has no prognostic value. Prediction of the clinical course of patients in an MCS by fMRI was considerably less accurate than in patients in a VS.


Assuntos
Estado Vegetativo Persistente/fisiopatologia , Adolescente , Adulto , Idoso , Estado de Consciência/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Prognóstico , Recuperação de Função Fisiológica , Centros de Reabilitação , Adulto Jovem
11.
Ecol Evol ; 13(10): e10592, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37841223

RESUMO

Practical lab skills are rarely directly assessed. To improve constructive alignment between the described learning outcomes of practical skills and assessment, we developed and tested a certification procedure for microscopy skills. The procedure was embedded into the ordinary learning activity, so no additional time was needed. Three slightly different protocols were developed within the framework of sociocultural learning theory and built like a skill ladder, including direct peer assessment and elements of gamified learning. The protocols varied slightly in the way students were prepared for the certification, the number of steps/levels of achievement, and the consequences of failing. We tested the protocols at three different academic institutions and within 11 courses of varying sizes and academic levels in biology or geology. Feedbacks were collected through online surveys (n = 207) or orally after sessions. One protocol provided instruction videos as preparation material. Instruction videos provided increased understanding of the task, but tactile training was most important for learning. Regardless of institution, type of preparation, and level of former experience, the certification procedure made students clearly more engaged in the exercise. The majority reported that the certification procedure increased their motivation to learn, increased their perceived learning outcome, and was appropriate for assessing practical skills. Students with no or little experience in microscopy before the exercise were more positive about the certification procedure compared to skilled students, and the level of engagement and preparation was higher when there were some consequences of failing. Most students felt comfortable being certified by peers, but some students expressed concern about peers making mistakes. The presented certification procedure can easily be adapted to assess other practical skills and, with some adjustments, be an efficient method for assessment-as-learning, merging formative- and summative assessment.

12.
Neuroimage ; 59(2): 1727-34, 2012 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-21907809

RESUMO

Borderline personality disorder (BPD) is characterized by emotional dysregulation and a high prevalence of traumatic stress. Recent estimates suggest that 2-6% of non-clinical populations suffer from BPD. Despite this relevance, this is the first study considering the neural mechanisms underlying trauma-history and temporal features of cognitive reappraisal in non-clinical BPD patients using script-driven stimuli. Using functional magnetic resonance imaging (fMRI), we examined subjective ratings of negative emotional experience and brain activity following up- and down-regulation of emotional responses to standardized negative scripts in 43 women: 14 trauma-exposed BPD patients (BPD), 14 trauma-exposed healthy subjects without posttraumatic stress disorder (non-PTSD), and 15 non-traumatized healthy subjects (HC). Behaviorally, all groups were able to use cognitive reappraisal to up- and down-regulate negative emotions. HC subjects showed increased early activation in the prefrontal cortex (PFC) and the amygdala following up-regulation of emotions to negative scripts, whereas BPD and non-PTSD subjects showed early deactivation in the PFC. Additionally, the anterior cingulate cortex was more activated in HC subjects than in BPD and non-PTSD subjects during up- and down-regulation. No significant group differences were found between BPD patients and non-PTSD. BPD patients and healthy individuals with trauma history do not engage the cognitive control regions to the extent than HC subjects do when employing down-regulation of negative emotions. They also do not activate the brain regions associated with emotional up-regulation. These findings may reflect compensatory changes associated with trauma-exposure.


Assuntos
Afeto , Transtorno da Personalidade Borderline/fisiopatologia , Encéfalo/fisiopatologia , Cognição , Emoções , Distância Psicológica , Ferimentos e Lesões/fisiopatologia , Adulto , Transtorno da Personalidade Borderline/etiologia , Feminino , Humanos , Ferimentos e Lesões/complicações
13.
Ecol Lett ; 15(2): 164-75, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22136670

RESUMO

Understanding the sensitivity of tundra vegetation to climate warming is critical to forecasting future biodiversity and vegetation feedbacks to climate. In situ warming experiments accelerate climate change on a small scale to forecast responses of local plant communities. Limitations of this approach include the apparent site-specificity of results and uncertainty about the power of short-term studies to anticipate longer term change. We address these issues with a synthesis of 61 experimental warming studies, of up to 20 years duration, in tundra sites worldwide. The response of plant groups to warming often differed with ambient summer temperature, soil moisture and experimental duration. Shrubs increased with warming only where ambient temperature was high, whereas graminoids increased primarily in the coldest study sites. Linear increases in effect size over time were frequently observed. There was little indication of saturating or accelerating effects, as would be predicted if negative or positive vegetation feedbacks were common. These results indicate that tundra vegetation exhibits strong regional variation in response to warming, and that in vulnerable regions, cumulative effects of long-term warming on tundra vegetation - and associated ecosystem consequences - have the potential to be much greater than we have observed to date.


Assuntos
Adaptação Biológica , Ecossistema , Aquecimento Global , Desenvolvimento Vegetal , Regiões Árticas , Biodiversidade , Modelos Biológicos
14.
Cogn Affect Behav Neurosci ; 11(3): 386-95, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21533882

RESUMO

The human voice is one of the principal conveyers of social and affective communication. Recent neuroimaging studies have suggested that observing pain in others activates neural representations similar to those from the first-hand experience of pain; however, studies on pain expressions in the auditory channel are lacking. We conducted a functional magnetic resonance imaging study to examine brain responses to emotional exclamations of others' pain. The control condition comprised positive (e.g., laughing) or negative (e.g., snoring) stimuli of the human voice that were not associated with pain and suffering. Compared to these control stimuli, pain-related exclamations elicited increased activation in the superior and middle temporal gyri, left insula, secondary somatosensory cortices, thalamus, and right cerebellum, as well as deactivation in the anterior cingulate cortex. The left anterior insular and thalamic activations correlated significantly with the Empathic Concern subscale of the Interpersonal Reactivity Index. Thus, the brain regions involved in hearing others' pain are similar to those activated in the empathic processing of visual stimuli. Additionally, the findings emphasise the modulating role of interindividual differences in affective empathy.


Assuntos
Encéfalo/fisiologia , Empatia/fisiologia , Dor/psicologia , Adulto , Mapeamento Encefálico , Emoções/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Neuroimagem
15.
Oecologia ; 166(2): 565-76, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21170749

RESUMO

The inclusion of environmental variation in studies of recruitment is a prerequisite for realistic predictions of the responses of vegetation to a changing environment. We investigated how seedling recruitment is affected by seed availability and microsite quality along a steep environmental gradient in dry tundra. A survey of natural seed rain and seedling density in vegetation was combined with observations of the establishment of 14 species after sowing into intact or disturbed vegetation. Although seed rain density was closely correlated with natural seedling establishment, the experimental seed addition showed that the microsite environment was even more important. For all species, seedling emergence peaked at the productive end of the gradient, irrespective of the adult niches realized. Disturbance promoted recruitment at all positions along the environmental gradient, not just at high productivity. Early seedling emergence constituted the main temporal bottleneck in recruitment for all species. Surprisingly, winter mortality was highest at what appeared to be the most benign end of the gradient. The results highlight that seedling recruitment patterns are largely determined by the earliest stages in seedling emergence, which again are closely linked to microsite quality. A fuller understanding of microsite effects on recruitment with implications for plant community assembly and vegetation change is provided.


Assuntos
Meio Ambiente , Plântula/fisiologia , Sementes/fisiologia , Espécies Introduzidas , Microclima , Densidade Demográfica , Suécia
16.
Neuroimage Clin ; 31: 102716, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34144346

RESUMO

There is much controversy about the potential impact of spinal cord injury (SCI) on brain anatomy and function, which is mirrored in the substantial divergence of findings between animal models and human imaging studies. Given recent advances in quantitative magnetic resonance imaging (MRI) we sought to tackle the unresolved question about the link between the presumed injury associated volume differences and underlying brain tissue property changes in a cohort of chronic complete SCI patients. Using the established computational anatomy methods of voxel-based morphometry (VBM) and voxel-based quantification (VBQ), we performed statistical analyses on grey and white matter volumes as well as on parameter maps indicative for myelin, iron, and free tissue water content in the brain of complete SCI patients (n = 14) and healthy individuals (n = 14). Our regionally unbiased white matter analysis showed a significant volume reduction of the dorsal aspect at the junction between the most rostral part of the spinal cord and the medulla oblongata consistent with Wallerian degeneration of proprioceptive axons in the dorsal column tracts in SCI subjects. This observation strongly correlated with spinal cord atrophy assessed by quantification of the spinal cord cross-sectional area at the cervical level C2/3. These findings suggest that Wallerian degeneration of the dorsal column tracts represents a main contributor to the observed spinal cord atrophy, which is highly consistent with preclinical histological evidence of remote changes in the central nervous system secondary to SCI. Structural changes in other brain regions representing remote changes in the course of chronic SCI could neither be confirmed by conventional VBM nor by VBQ analysis. Whether and how MRI based brain morphometry and brain tissue property analysis will inform clinical decision making and clinical trial outcomes in spinal cord medicine remains to be determined.


Assuntos
Traumatismos da Medula Espinal , Substância Branca , Encéfalo , Tronco Encefálico , Humanos , Imageamento por Ressonância Magnética , Medula Espinal/diagnóstico por imagem , Traumatismos da Medula Espinal/diagnóstico por imagem
17.
Curr Psychiatry Rep ; 12(3): 186-95, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20425279

RESUMO

Early views of borderline personality disorder (BPD) were based on the idea that patients with this pathology were "on the border" of psychosis. However, more recent studies have not supported this view, although they have found evidence of a malevolent interpersonal evaluation and a significant proportion of BPD patients showing psychotic symptoms. For example, in one study, 24% of BPD patients reported severe psychotic symptoms and about 75% had dissociative experiences and paranoid ideation. Thus, we start with an overview regarding the prevalence of psychotic symptoms in BPD patients. Furthermore, we report findings of studies investigating the role of comorbidity (eg, post-traumatic stress disorder) in the severity and frequency of psychotic symptoms in BPD patients. We then present results of genetic and neurobiological studies comparing BPD patients with patients with schizophrenia or nonschizophrenic psychotic disorders. In conclusion, this review reveals that psychotic symptoms in BPD patients may not predict the development of a psychotic disorder but are often permanent and severe and need careful consideration by clinicians. Therefore, adequate diagnosis and treatment of psychotic symptoms in BPD patients is emphasized.


Assuntos
Antipsicóticos/uso terapêutico , Transtorno da Personalidade Borderline/epidemiologia , Transtornos Psicóticos/epidemiologia , Transtorno da Personalidade Borderline/diagnóstico , Transtorno da Personalidade Borderline/tratamento farmacológico , Criança , Comorbidade , Transtornos Dissociativos/diagnóstico , Transtornos Dissociativos/tratamento farmacológico , Transtornos Dissociativos/epidemiologia , Humanos , Acontecimentos que Mudam a Vida , Transtornos Psicóticos/diagnóstico , Transtornos Psicóticos/tratamento farmacológico , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Transtornos de Estresse Pós-Traumáticos/psicologia
18.
Eur J Neurosci ; 29(4): 823-32, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19200075

RESUMO

Functional magnetic resonance imaging was used to investigate the role of the hippocampus, amygdala and medial prefrontal cortex (mPFC) in a contextual conditioning and extinction paradigm provoking anxiety. Twenty-one healthy persons participated in a differential context conditioning procedure with two different background colours as contexts. During acquisition increased activity to the conditioned stimulus (CS+) relative to the CS- was found in the left hippocampus and anterior cingulate cortex (ACC). The amygdala, insula and inferior frontal cortex were differentially active during late acquisition. Extinction was accompanied by enhanced activation to CS+ vs. CS- in the dorsal anterior cingulate cortex (dACC). The results are in accordance with animal studies and provide evidence for the important role of the hippocampus in contextual learning in humans. Connectivity analyses revealed correlated activity between the left posterior hippocampus and dACC (BA32) during early acquisition and the dACC, left posterior hippocampus and right amygdala during extinction. These data are consistent with theoretical models that propose an inhibitory effect of the mPFC on the amygdala. The interaction of the mPFC with the hippocampus may reflect the context-specificity of extinction learning.


Assuntos
Tonsila do Cerebelo/fisiologia , Condicionamento Psicológico/fisiologia , Extinção Psicológica/fisiologia , Hipocampo/fisiologia , Córtex Pré-Frontal/fisiologia , Adulto , Córtex Cerebral/fisiologia , Sinais (Psicologia) , Estimulação Elétrica , Feminino , Resposta Galvânica da Pele , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Estimulação Luminosa , Análise de Regressão , Adulto Jovem
19.
Cogn Behav Neurol ; 22(1): 53-62, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19372771

RESUMO

OBJECTIVES: To evaluate cortical information processing (particularly, semantic processing) in acute nontraumatic coma by means of event-related brain potentials (ERPs). METHODS: The tests included measures of obligatory auditory processing (N100), automatic (Mismatch Negativity) and controlled (P300) detection of stimulus deviance, and semantic processing (ERP effects in word pairs and sentences). The tests were presented to 20 healthy participants and 42 coma patients with Glasgow Coma Scale <9. RESULTS: Responders (ie, patients whose ERP data indicate that their brain was able to process the corresponding stimuli) were found in each ERP test, and their distribution was statistically different from that expected by chance. Particularly, 7 responders were found in the word pair paradigm and 3 responders in the sentence paradigm. The P300 responsiveness highly correlated with other ERP responses, with Glasgow Coma Scale and with the future development of coma (ie, P300 on day 4 was related to the clinical state on day 20). CONCLUSIONS: Results suggest a wide range of cortical information processing in coma, including semantic processing. The question is discussed of whether, and to what extent, these processing operations are related to conscious awareness of stimuli.


Assuntos
Córtex Cerebral/fisiologia , Coma/fisiopatologia , Coma/psicologia , Processos Mentais/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Percepção Auditiva/fisiologia , Estado de Consciência , Interpretação Estatística de Dados , Eletroencefalografia , Potenciais Evocados P300 , Potenciais Evocados/fisiologia , Feminino , Escala de Coma de Glasgow , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Tomografia Computadorizada por Raios X
20.
Carbohydr Res ; 340(13): 2144-9, 2005 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-16054609

RESUMO

The deposition of alternating layers of pectin and chitosan at a solid surface was studied using surface plasmon resonance. The binding of biopolymer to the surface was irreversible over the time scales examined. The deposition was dependent on the flow rate through the measurement cell with mass transport limitation at lower flow rates. The thickness of the deposited layer was dependent on the biopolymer concentration and was particularly marked for pectin. This was consistent with a process of initial attachment, followed by a slower structural rearrangement, which was inhibited at high initial surface concentrations of adsorbed biopolymer. Sequential deposition resulted in the formation of multilayers with an essentially linear growth rate.


Assuntos
Quitosana/química , Pectinas/química , Adsorção , Eletrólitos/química , Membranas Artificiais , Polímeros/síntese química , Análise Espectral , Ressonância de Plasmônio de Superfície , Propriedades de Superfície
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