Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 37
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Semin Cell Dev Biol ; 145: 13-21, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-35277332

RESUMEN

Historically, the empirical study of phenotypic diversification has fallen into two rough camps; (1) "structuralist approaches" focusing on developmental constraint, bias, and innovation (with evo-devo at the core); and (2) "adaptationist approaches" focusing on adaptation, and natural selection. Whilst debates, such as that surrounding the proposed "Extended" Evolutionary Synthesis, often juxtapose these two positions, this review focuses on the grey space in between. Specifically, here I present a novel analysis of structuralism which enables us to take a more nuanced look at the motivations behind the structuralist and adaptationist positions. This makes clear how the two approaches can conflict, and points of potential commensurability. The review clarifies (a) the value of the evo-devo approach to phenotypic diversity, but also (b) how it properly relates to other predominant approaches to the same issues in evolutionary biology more broadly.


Asunto(s)
Evolución Biológica , Amigos , Humanos
2.
J Phys Chem A ; 127(44): 9220-9228, 2023 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-37906705

RESUMEN

In this study, mixed carbonyl and nitrous oxide complexes with Rh+ were studied by mass-selective infrared photodissociation spectroscopy in a molecular beam. The infrared spectra, recorded in the region of the CO and N2O N═N stretches, were assigned and interpreted with the aid of simulated spectra of low-energy structural isomers. Clear evidence of an inner coordination shell of four ligands is observed. The observed vibrational structure can be understood on the basis of local mode vibrations in the two ligands. However, there is also evidence of multiple low-lying isomers and cooperative binding effects between the two ligands. In particular, σ donation from directly coordinated nitrous oxide ligands drives more classical carbonyl bonding than has been observed in pure carbonyl complexes. The observed fragmentation branching ratios following resonant infrared absorption are explained by simple statistical and energetic arguments, providing a contrast with those of equivalent Au+ complexes.

3.
Behav Brain Sci ; 46: e194, 2023 09 11.
Artículo en Inglés | MEDLINE | ID: mdl-37694935

RESUMEN

We are less optimistic than Madole & Harden that family-based genome-wide association studies (GWASs) will lead to significant second-generation causal knowledge. Despite bearing some similarities, family-based GWASs and randomised controlled trials (RCTs) are not identical. Most RCTs assess a relatively homogenous causal stimulus as a treatment, whereas GWASs assess highly heterogeneous causal stimuli. Thus, GWAS results will not translate so easily into second-generation causal knowledge.


Asunto(s)
Estudio de Asociación del Genoma Completo , Conocimiento , Humanos , Causalidad , Ensayos Clínicos Controlados Aleatorios como Asunto
4.
Behav Brain Sci ; 45: e252, 2022 11 10.
Artículo en Inglés | MEDLINE | ID: mdl-36353897

RESUMEN

On Jagiello et al.'s cultural action framework, end-goal resolvability and causal transparency make possible the transmission of complex technologies through low-fidelity cultural learning. We offer three further features of goal-directed action sequences - specificity, riskiness, and complexity - which alter the effectiveness of low-fidelity cultural learning. Incorporating these into the cultural action framework generates further novel, testable predictions for bifocal stance theory.


Asunto(s)
Objetivos , Motivación , Humanos , Aprendizaje
5.
J Phys Chem A ; 125(33): 7266-7277, 2021 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-34433267

RESUMEN

We report a combined experimental and computational study of the structure and fragmentation dynamics of mixed ligand gas-phase ion-molecule complexes. Specifically, we have studied the infrared spectroscopy and vibrationally induced photofragmentation dynamics of mass-selected Au(CO)x(N2O)y+ complexes. The structures can be understood on the basis of local CO and N2O chromophores in different solvation shells with CO found preferentially in the core. Rich fragmentation dynamics are observed as a function of complex composition and the vibrational mode excited. The dynamics are characterized in terms of branching ratios for different ligand loss channels in light of calculated internal energy distributions. Intramolecular vibrational redistribution appears to be rapid, and dissociation is observed into all energetically accessible channels with little or no evidence for preferential breaking of the weakest intermolecular interactions.

6.
Behav Brain Sci ; 43: e95, 2020 05 28.
Artículo en Inglés | MEDLINE | ID: mdl-32460923

RESUMEN

Veissière et al. must sacrifice explanatory realism and precision in order to develop a unified formal model. Drawing on examples from cognitive archeology, we argue that this makes it difficult for them to derive the kinds of testable predictions that would allow them to resolve debates over the nature of human social cognition and cultural acquisition.


Asunto(s)
Cognición , Conducta Social , Humanos
7.
Am J Physiol Heart Circ Physiol ; 317(6): H1203-H1209, 2019 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-31675259

RESUMEN

Sympathetic baroreflex sensitivity (BRS) is a measure of how effectively the baroreflex buffers beat-to-beat changes in blood pressure through the modulation of muscle sympathetic nerve activity (MSNA). However, current methods of assessment do not take into account the transduction of sympathetic nerve activity at the level of the vasculature, which is known to vary between individuals. In this study we tested the hypothesis that there is an inverse relationship between sympathetic BRS and vascular transduction. In 38 (18 men) healthy adults, continuous measurements of blood pressure, MSNA and superficial femoral artery diameter and blood flow (Doppler ultrasound) were recorded during 10 min of rest. Spontaneous sympathetic BRS was quantified as the relationship between diastolic pressure and MSNA burst incidence. Vascular transduction was quantified by plotting the changes in leg vascular conductance for 10 cardiac cycles following each burst of MSNA, and taking the nadir. In men, sympathetic BRS was inversely related to vascular transduction (r = -0.49; P = 0.04). However, this relationship was not present in women (r = -0.17; P = 0.47). To conclude, an interaction exists between sympathetic BRS and vascular transduction in healthy men, such that men with high sympathetic BRS have low vascular transduction and vice versa. This may be to ensure that blood pressure is regulated effectively, although further research is needed to explore what mechanisms are involved and examine why this relationship was not apparent in women.NEW & NOTEWORTHY Evidence suggests that compensatory interactions exist between factors involved in cardiovascular control. This study was the first to demonstrate an inverse relationship between sympathetic BRS and beat-to-beat vascular transduction. Those with low sympathetic BRS had high vascular transduction and vice versa. However, this interaction was present in young men but not women.


Asunto(s)
Barorreflejo , Presión Sanguínea , Sistema Nervioso Simpático/fisiología , Adolescente , Adulto , Vasos Sanguíneos/inervación , Vasos Sanguíneos/fisiología , Femenino , Frecuencia Cardíaca , Humanos , Masculino , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/inervación , Conducción Nerviosa , Factores Sexuales
8.
Hum Brain Mapp ; 38(2): 869-881, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27696604

RESUMEN

Experimentally induced tonic muscle pain evokes divergent muscle vasoconstrictor responses, with some individuals exhibiting a sustained increase in muscle sympathetic nerve activity (MSNA), and others a sustained decrease. These patterns cannot be predicted from an individual's baseline physiological or psychological measures. The aim of this study was to investigate whether the different muscle sympathetic responses to tonic muscle pain were associated with differential changes in regional brain activity. Functional magnetic resonance imaging (fMRI) of the brain was performed concurrently with microelectrode recording of MSNA from the peroneal nerve during a 40-min infusion of hypertonic saline into the ipsilateral tibialis anterior muscle. MSNA increased in 26 and decreased in 11 of 37 subjects during tonic muscle pain. Within the prefrontal and cingulate cortices, precuneus, nucleus accumbens, caudate nucleus, and dorsomedial hypothalamus, blood oxygen level dependent (BOLD) signal intensity increased in the increasing-MSNA group and remained at baseline or decreased in the decreasing-MSNA group. Similar responses occurred in the dorsolateral pons and in the region of the rostral ventrolateral medulla. By contrast, within the region of the dorsolateral periaqueductal gray (dlPAG) signal intensity initially increased in both groups but returned to baseline levels only in the increasing-MSNA group. These results suggest that the divergent sympathetic responses to muscle pain result from activation of a neural pathway that includes the dlPAG, an area thought to be responsible for the behavioral and cardiovascular responses to psychological rather than physical stressors. Hum Brain Mapp 38:869-881, 2017. © 2016 Wiley Periodicals, Inc.


Asunto(s)
Encéfalo/fisiopatología , Mialgia/patología , Mialgia/fisiopatología , Sistema Nervioso Simpático/fisiopatología , Presión Sanguínea/fisiología , Encéfalo/diagnóstico por imagen , Potenciales Evocados/fisiología , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Oxígeno/sangre , Dimensión del Dolor , Estimulación Física/efectos adversos , Psicofísica , Respiración , Adulto Joven
9.
Clin Auton Res ; 27(6): 401-406, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28674869

RESUMEN

OBJECTIVE AND METHODS: Muscle sympathetic nerve activity and baroreflex sensitivity were examined at rest before, during (weeks 6, 11, 17, 22, 25, 33 and 36) and after a normotensive pregnancy. RESULTS: Muscle sympathetic nerve activity is elevated during pregnancy with a large peak in the first trimester (Δ17 bursts/min) and a secondary peak in the third trimester (Δ11 bursts/min). Cardiac baroreflex sensitivity peaked in the first trimester (10 vs. 6 ms/mmHg pre-pregnancy), whereas sympathetic baroreflex sensitivity was greater throughout. INTERPRETATION: The increase in sympathetic outflow early in pregnancy cannot be explained by a reduction in baroreflex sensitivity, while the secondary increase in burst frequency in the third trimester may, in part, be explained by the elevated heart rate.


Asunto(s)
Fibras Adrenérgicas/fisiología , Presión Sanguínea/fisiología , Frecuencia Cardíaca/fisiología , Músculo Esquelético/inervación , Músculo Esquelético/fisiología , Primer Trimestre del Embarazo/fisiología , Adulto , Barorreflejo/fisiología , Femenino , Humanos , Recién Nacido , Estudios Longitudinales , Embarazo , Sistema Nervioso Simpático/fisiología
10.
PLoS Pathog ; 10(3): e1004006, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24626195

RESUMEN

Human T-lymphotropic virus type 1 (HTLV-1) and type 2 (HTLV-2) both cause lifelong persistent infections, but differ in their clinical outcomes. HTLV-1 infection causes a chronic or acute T-lymphocytic malignancy in up to 5% of infected individuals whereas HTLV-2 has not been unequivocally linked to a T-cell malignancy. Virus-driven clonal proliferation of infected cells both in vitro and in vivo has been demonstrated in HTLV-1 infection. However, T-cell clonality in HTLV-2 infection has not been rigorously characterized. In this study we used a high-throughput approach in conjunction with flow cytometric sorting to identify and quantify HTLV-2-infected T-cell clones in 28 individuals with natural infection. We show that while genome-wide integration site preferences in vivo were similar to those found in HTLV-1 infection, expansion of HTLV-2-infected clones did not demonstrate the same significant association with the genomic environment of the integrated provirus. The proviral load in HTLV-2 is almost confined to CD8+ T-cells and is composed of a small number of often highly expanded clones. The HTLV-2 load correlated significantly with the degree of dispersion of the clone frequency distribution, which was highly stable over ∼8 years. These results suggest that there are significant differences in the selection forces that control the clonal expansion of virus-infected cells in HTLV-1 and HTLV-2 infection. In addition, our data demonstrate that strong virus-driven proliferation per se does not predispose to malignant transformation in oncoretroviral infections.


Asunto(s)
Linfocitos T CD8-positivos/virología , Infecciones por HTLV-II/genética , Infecciones por HTLV-II/virología , Células Clonales/virología , Biología Computacional , Citometría de Flujo , Infecciones por HTLV-I/genética , Infecciones por HTLV-I/virología , Ensayos Analíticos de Alto Rendimiento , Virus Linfotrópico T Tipo 1 Humano/genética , Virus Linfotrópico T Tipo 2 Humano/genética , Humanos , Provirus/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Carga Viral/genética , Integración Viral/genética
11.
Exp Physiol ; 98(2): 405-14, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22923230

RESUMEN

Progressive asphyxia, produced by a prolonged voluntary breath hold (end-expiratory apnoea), evokes large bursts of muscle sympathetic nerve activity (MSNA). These bursts increase in amplitude until the asphyxic break point is reached, at which point the bursts are inhibited. We tested the hypothesis that lung inflation, rather than relief from hypoxia and hypercapnia, is responsible for the inhibition of MSNA. Multiunit MSNA was recorded from motor fascicles of the common peroneal nerve in 11 subjects. Following a period of quiet breathing, subjects were instructed to behave as follows: (i) to hold their breath in expiration for as long as they could (mean duration 32.3 ± 1.9 s); (ii) to take a single breath of room air, 100% N(2) or 10% CO(2) + 90% N(2) at the asphyxic break point; (iii) to exhale and continue the apnoea until the next break point; and then (iv) to resume breathing. All subjects reported relief during inhalation of any gas, and could continue holding their breath for a further 30.7 ± 2.8 s with room air, 18.6 ± 1.7 s with N(2) and 11.8 ± 1.8 s with 10% CO(2) + 90% N(2). Despite the exaggerated chemoreceptor drive in the latter two conditions (hence the significantly shorter latencies to the subsequent asphyxic break point), the inhibition still occurred; moreover, there was no significant difference in duration of the inhibition of MSNA following the single breath of room air (7.6 ± 0.7 s), N(2) (6.2 ± 0.6 s) or 10% CO(2) + 90% N(2) (5.5 ± 0.4 s). Following the resumption of breathing, however, the duration of MSNA inhibition (11.0 ± 1.0 s) was significantly longer than that following a single breath. To investigate the involvement of chemoreceptors in the respiratory modulation of MSNA further, the same gases were used during an inspiratory-capacity apnoea, which causes a brief inhibition of MSNA during the inflation phase and a sustained increase during the hold phase. The duration of the apnoea was shortest after a breath of 10% O(2) + 90% N(2), but the latency until the bursts resumed after the inspiratory breath hold were similar for all gases, which suggests that there is no chemoreceptor involvement during the sympathetic silence seen during the inflation phase of inspiratory-capacity apnoeas. We conclude that neither peripheral nor central chemoreceptors are responsible for the inhibition of muscle vasoconstrictor drive following an end-expiratory apnoea or an end-inspiratory apnoea. Rather, we suggest that the inhibition is evoked by stretch receptors in the lungs and/or chest wall, which may also contribute to the longer inhibition associated with the hyperventilation following the subsequent resumption of rhythmic breathing.


Asunto(s)
Apnea/fisiopatología , Asfixia/fisiopatología , Células Quimiorreceptoras/metabolismo , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/inervación , Nervio Peroneo/fisiopatología , Respiración , Vasoconstricción , Vigilia , Adolescente , Adulto , Análisis de Varianza , Apnea/metabolismo , Asfixia/metabolismo , Presión Sanguínea , Contencion de la Respiración , Dióxido de Carbono/administración & dosificación , Dióxido de Carbono/metabolismo , Femenino , Humanos , Hipercapnia/metabolismo , Hipercapnia/fisiopatología , Hipoxia/metabolismo , Hipoxia/fisiopatología , Pulmón/inervación , Masculino , Nueva Gales del Sur , Nitrógeno/administración & dosificación , Nitrógeno/metabolismo , Oxígeno/administración & dosificación , Oxígeno/metabolismo , Nervio Peroneo/metabolismo , Receptores de Estiramiento Pulmonares/metabolismo , Factores de Tiempo , Adulto Joven
12.
Neuroimage ; 62(1): 30-40, 2012 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-22580171

RESUMEN

The sympathetic innervation of the skin not only primarily subserves thermoregulation, but has also been commandeered as a means of emotional expression. While the majority of brain imaging studies of emotion have utilised the galvanic skin response as a means of inferring changes in skin sympathetic nerve activity (SSNA), spontaneous fluctuations in the galvanic skin response bear little relation to spontaneous fluctuations in SSNA. To improve our understanding of the central neural processes involved in the generation of autonomic emotional markers, we recorded SSNA concurrently with brain functional magnetic resonance imaging in 13 subjects. Emotional changes were evoked by presentation of positively-charged (erotica) or negatively-charged (mutilation) images from the International Affective Picture System. Positive and negative emotionally-charged images evoked significant increases in total SSNA and signal intensity in the orbital, dorsolateral and ventromedial prefrontal cortices, amygdala, nucleus accumbens and anterior insula. Increases in signal intensity during increases in SSNA occurred in a number of brain regions, including the central and lateral amygdala, dorsolateral pons, thalamus, nucleus accumbens, and cerebellar cortex. Signal intensity decreases during SSNA increases occurred in the left orbitofrontal, frontal and right precuneus cortices. These data reveal for the first time, cortical and subcortical sites involved in generating SSNA changes during emotions.


Asunto(s)
Mapeo Encefálico/métodos , Encéfalo/fisiología , Emociones/fisiología , Fenómenos Fisiológicos de la Piel , Piel/inervación , Sistema Nervioso Simpático/fisiología , Percepción Visual/fisiología , Adolescente , Adulto , Velocidad del Flujo Sanguíneo/fisiología , Sistemas de Computación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven
13.
Clin Auton Res ; 22(4): 191-6, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22532273

RESUMEN

OBJECTIVE: Parkinson's disease (PD) is a degenerative neurological condition, associated with cardiovascular dysfunction. Many studies have utilised heart rate variability (HRV) to assess the autonomic nervous system in PD, but blood pressure variability (BPV) has received less attention. The purpose of the present study was to compare HRV and BPV between participants with established PD, extrapyramidal motor slowing (EPMS) (not reaching clinical criteria for PD), older healthy controls (OHC), and young healthy controls (YHC), in order to ascertain whether either of these measures can be used as an early marker of non-motor symptoms in PD. METHODS: HRV was assessed at rest and during 2 min of slow deep breathing in 97 participants, divided into four groups: YHC (20-30 years; n = 19); OHC (67-83 years; n = 28); EPMS (59-91 years; n = 25) and PD (61-84 years; n = 25). RESULTS: Spectral analysis of blood pressure was performed on stable non-invasive recordings of blood pressure obtained in 76 of the participants. Low frequency (LF) and high frequency (HF) components, and the LF/HF ratio, were measured. Significant differences were only seen between the YHC and the three older groups. For HRV this was seen at rest and during 2 min of slow deep breathing, whereas for BPV this was only seen during 2 min of slow deep breathing. INTERPRETATION: These data indicate that there are only age-related changes in HRV and BPV, and that neither technique is sensitive enough to provide an index of pre-clinical PD.


Asunto(s)
Enfermedades del Sistema Nervioso Autónomo/fisiopatología , Enfermedades de los Ganglios Basales/fisiopatología , Vías Eferentes/fisiopatología , Enfermedad de Parkinson/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Enfermedades del Sistema Nervioso Autónomo/diagnóstico , Enfermedades de los Ganglios Basales/diagnóstico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven
14.
Trends Cogn Sci ; 26(9): 738-750, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35773138

RESUMEN

Making inferences from behaviour to cognition is problematic due to a many-to-one mapping problem, in which any one behaviour can be generated by multiple possible cognitive processes. Attempts to cross this inferential gap when comparing human intelligence to that of animals or machines can generate great debate. Here, we discuss the challenges of making comparisons using 'success-testing' approaches and call attention to an alternate experimental framework, the 'signature-testing' approach. Signature testing places the search for information-processing errors, biases, and other patterns centre stage, rather than focussing predominantly on problem-solving success. We highlight current research on both biological and artificial intelligence that fits within this framework and is creating proactive research programs that make strong inferences about the similarities and differences between the content of human, animal, and machine minds.


Asunto(s)
Inteligencia Artificial , Inteligencia , Animales , Cognición , Humanos , Solución de Problemas
15.
J Am Heart Assoc ; 10(10): e018448, 2021 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-33942621

RESUMEN

Background Diesel exhaust (DE) emissions are a major contributor to ambient air pollution and are strongly associated with cardiovascular morbidity and mortality. Exposure to traffic-related particulate matter is linked with acute adverse cardiovascular events; however, the mechanisms are not fully understood. We examined the role of the autonomic nervous system during exposure to DE that has previously only been indirectly investigated. Methods and Results Using microneurography, we measured muscle sympathetic nerve activity (MSNA) directly in the peroneal nerve of 16 healthy individuals. MSNA, heart rate, and respiration were recorded while subjects rested breathing filtered air, filtered air with an exposure mask, and standardized diluted DE (300 µg/m3) through the exposure mask. Heart rate variability was assessed from an ECG. DE inhalation rapidly causes an increase in number of MSNA bursts as well as the size of bursts within 10 minutes, peaking by 30 minutes (P<0.001), compared with baseline filtered air with an exposure mask. No significant changes occurred in heart rate variability indices during DE exposure; however, MSNA frequency correlated negatively with total power (r2=0.294, P=0.03) and low frequency (r2=0.258, P=0.045). Heart rate correlated positively with MSNA frequency (r2=0.268, P=0.04) and the change in percentage of larger bursts (burst amplitude, height >50% of the maximum burst) from filtered air with an exposure mask (r2=0.368, P=0.013). Conclusions Our study provides direct evidence for the rapid modulation of the autonomic nervous system after exposure to DE, with an increase in MSNA. The quick increase in sympathetic outflow may explain the strong epidemiological data associating traffic-related particulate matter to acute adverse cardiovascular events such as myocardial infarction. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02892279.


Asunto(s)
Contaminantes Atmosféricos/efectos adversos , Enfermedades Cardiovasculares/etiología , Contracción Muscular/fisiología , Músculo Esquelético/inervación , Salud Pública , Sistema Nervioso Simpático/fisiopatología , Emisiones de Vehículos , Adulto , Enfermedades Cardiovasculares/epidemiología , Frecuencia Cardíaca/fisiología , Humanos , Incidencia , Masculino , Músculo Esquelético/fisiopatología , Población Urbana , Adulto Joven
16.
Clin Auton Res ; 19(4): 213-20, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19377855

RESUMEN

OBJECTIVES: Spinal cord injury results in loss of supraspinal control of sympathetic outflow, yet preservation of spinal reflexes. Given the importance of reflex activation of sympathetic vasoconstrictor neurones to the generation of autonomic dysreflexia, we assessed the input-output relationship of the spinal somatosympathetic reflex induced by electrical activation of cutaneous afferents over the lower abdominal wall. METHODS: In 13 spinal cord-injured subjects (C4-T10) we tested the hypothesis that the magnitude and duration of the vasoconstriction is directly related to the magnitude and duration of the stimulus train. Cutaneous vasoconstriction was measured with photoelectric plethysmography over a finger and toe; continuous blood pressure was recorded by radial artery tonometry, heart rate by ECG chest electrodes and sweat release by skin conductance. Four sets of trains of cutaneous electrical stimuli (20 Hz 1 s, 20 Hz 20 s, 20 Hz 1 s alternating on-and-off for 20 s and 1 Hz 20 s) were applied to the abdominal wall (10 mA) at 2-min intervals. RESULTS: Nine subjects showed vasoconstrictor responses to the stimulus trains. On average, both the magnitude and duration of the responses were similar irrespective of the type of stimulus train. INTERPRETATION: We conclude that there is a non-linear relationship between somatic inputs and sympathetic vasoconstrictor outputs, and argue that a sustained vasoconstriction need not imply continuous sensory input to the spinal cord.


Asunto(s)
Disreflexia Autónoma/fisiopatología , Reflejo/fisiología , Traumatismos de la Médula Espinal/fisiopatología , Sistema Nervioso Simpático/fisiología , Vasoconstricción/fisiología , Vías Aferentes/fisiología , Presión Sanguínea/fisiología , Estimulación Eléctrica , Humanos
17.
Monoclon Antib Immunodiagn Immunother ; 38(4): 162-170, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31260385

RESUMEN

Kinesin-like protein KIF20B, originally named M-phase phosphoprotein 1 (MPP1), is a plus-end-directed kinesin-related protein that exhibits in vitro microtubule-binding and -bundling properties as well as microtubule-stimulated ATPase activity. It has been characterized as a slow molecular motor that moves toward the plus-end of microtubules. Human autoantibodies directed against KIF20B have been described in up to 25% of patients with idiopathic ataxia and less commonly in other neuropathies and autoinflammatory conditions. One of the limitations of research into the structure and function of KIF20B has been a reliable monoclonal antibody that can be used in a variety of applications. To establish a reference standard for anti-KIF20B immunoassays and facilitate studies on the role of KIF20B in developmental cell biology, we developed an IgG1 monoclonal antibody, 10C7, which reacts with the cognate KIF20B protein in Western immunoblots and in addressable laser bead immunoassays. In HEp2 cells, leptomeningeal pericytes, and transfected HEK293T cells, indirect immunofluorescence studies showed that reactivity was mainly localized to a proportion of interphase nuclei, but during metaphase, it was redistributed throughout the cytoplasm and perichromatin mass. Later in telophase/anaphase, KIF20B was localized to the stem body and midzone of the midbody. 10C7 also showed remarkable staining of a subset of cells in the cerebellum, ovary, and testis tissues. KIF20B was shown to have extensive coiled-coil domains. The monoclonal antibody, 10C7, will be of value to diagnostic laboratory scientists interested in having a reliable reference standard for anti-KIF20B immunoassays as well as cell, molecular, and developmental biology researchers.


Asunto(s)
Anticuerpos Monoclonales/inmunología , Mapeo Epitopo , Hibridomas/inmunología , Cinesinas/antagonistas & inhibidores , Cinesinas/inmunología , Neoplasias Laríngeas/metabolismo , Proteínas Recombinantes/inmunología , Anticuerpos Monoclonales/biosíntesis , Anticuerpos Monoclonales/farmacología , Formación de Anticuerpos , Humanos , Neoplasias Laríngeas/diagnóstico , Neoplasias Laríngeas/inmunología , Células Tumorales Cultivadas
18.
Auton Neurosci ; 209: 71-78, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-28728939

RESUMEN

Autonomic dysreflexia is a dangerous elevation in blood pressure in people with spinal cord injury (SCI), produced by a spinally-mediated reflex activation of sympathetic vasoconstrictor neurones supplying skeletal muscle and the gut. Current dogma states that, apart from visceral inputs - such as those originating from a distended bladder or impacted colon - autonomic dysreflexia is triggered by noxious inputs below the lesion. However, while selective stimulation of small-diameter afferents in muscle or skin evokes a sustained increase in muscle sympathetic nerve activity and blood pressure, and a transient increase in skin sympathetic nerve activity and decrease in skin blood flow in able-bodied subjects, such noxious inputs have no effects on blood pressure and skin blood flow in SCI individuals. Conversely, weak electrical stimulation over the abdominal wall, which in able-bodied subjects is not painful and activates large-diameter cutaneous afferents, causes a marked increase in blood pressure in SCI but not in able-bodied subjects. Moreover, vibration of the penis in spinal-injured men, which is not noxious, caused marked vasoconstriction and increases in blood pressure, similar to those produced by non-noxious distension of the bladder during urodynamics procedures. This suggests that activation of large-diameter somatic afferents, not small-diameter afferents, triggers the increases in vasoconstrictor drive that lead to autonomic dysreflexia, arguing against current dogma on the importance of noxious inputs in triggering autonomic dysreflexia.


Asunto(s)
Disreflexia Autónoma/fisiopatología , Estimulación Eléctrica , Traumatismos de la Médula Espinal/fisiopatología , Sistema Nervioso Simpático/fisiopatología , Animales , Presión Sanguínea/fisiología , Humanos , Médula Espinal/fisiopatología , Traumatismos de la Médula Espinal/terapia
19.
Brain Behav ; 8(3): e00888, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29541532

RESUMEN

Introduction: Long-lasting experimental muscle pain elicits divergent muscle sympathetic responses, with some individuals exhibiting a persistent increase in muscle sympathetic nerve activity (MSNA), and others a decrease. These divergent responses are thought to result from sustained functional changes in specific brain regions that modulate the cardiovascular responses to pain. Aim: The aim of this study was to investigate brain regions that are functionally coupled to the generation of an MSNA burst at rest and to determine their behavior during tonic muscle pain. Methods: Functional magnetic resonance imaging of the brain was performed concurrently with microelectrode recording of MSNA from the common peroneal nerve during a 40 min infusion of hypertonic saline into the ipsilateral tibialis anterior muscle of 37 healthy human subjects. Results: At rest, blood oxygen level-dependent signal intensity coupled to bursts of MSNA increased in the rostral ventrolateral medulla, insula, dorsolateral prefrontal cortex, posterior cingulate cortex, and precuneus and decreased in the region of the midbrain periaqueductal gray. During pain, MSNA-coupled signal intensity was greater in the region of the nucleus tractus solitarius, midbrain periaqueductal gray, dorsolateral prefrontal, medial prefrontal, and anterior cingulate cortices, than at rest. Conversely, MSNA-coupled signal intensity decreased during pain in parts of the prefrontal cortex. Conclusions: These results suggest that multiple brain regions are recruited in a burst-to-burst manner, and the magnitude of these signal changes is correlated to the overall change in MSNA amplitude during tonic muscle pain.


Asunto(s)
Encéfalo/fisiopatología , Músculo Esquelético/inervación , Mialgia/fisiopatología , Sistema Nervioso Simpático/fisiopatología , Adolescente , Adulto , Encéfalo/diagnóstico por imagen , Mapeo Encefálico/métodos , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Nervio Peroneo/fisiopatología , Tiempo , Adulto Joven
20.
Front Neurol ; 9: 943, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30483208

RESUMEN

Introduction: Mal de Debarquement Syndrome (MdDS) is a neurological disorder which affects the vestibular system pathways, manifesting as a constant sensation of movement in the form of rocking, bobbing, or swaying. The mechanism of MdDS is poorly understood and there is a lack of awareness amongst medical professionals about the condition. This study aimed to examine treatments and symptom management strategies used by MdDS patients and evaluate their self-reported effectiveness. Method: Motion-Triggered and Spontaneous/Other onset MdDS patients responded to a set of comprehensive questions as a retrospective survey regarding epidemiological details, diagnostic procedures, onset, and symptom triggers, hormonal influences as well as treatments and symptom management strategies used to reduce symptoms. The Motion-Triggered questionnaire was made available through Survey Monkey and the Spontaneous/Other Onset questionnaire through Qualtrics. The link for each questionnaire was made available on online MdDS support groups and on various research websites. Descriptive statistics were used for epidemiological data and Pearson's Chi Square tests were used for comparisons between and within both subtype groups. Results: A total of 370 patients participated in the surveys, with 287 valid responses collected for the section regarding treatment and symptom management strategies. The success of the treatments and symptom management strategies did not vary between subtypes Benzodiazepines/Antidepressants were reported as being most beneficial in reducing symptoms in both groups. Conclusion: This was the first attempt to evaluate the reported success of treatments and symptom management strategies in MdDS patients by assessing the patients' perceived helpfulness. The treatments and symptom management strategies reported to be the most helpful in managing and/or reducing symptoms are proposed to be effective due to their stress-reducing capacities. We hope this study will broaden MdDS awareness and that this study will increase patient knowledge regarding treatments and symptom management strategies that other patients found helpful.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA