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1.
EMBO J ; 40(6): e105123, 2021 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-33555074

RESUMEN

Similar to the brain, the eye is considered an immune-privileged organ where tissue-resident macrophages provide the major immune cell constituents. However, little is known about spatially restricted macrophage subsets within different eye compartments with regard to their origin, function, and fate during health and disease. Here, we combined single-cell analysis, fate mapping, parabiosis, and computational modeling to comprehensively examine myeloid subsets in distinct parts of the eye during homeostasis. This approach allowed us to identify myeloid subsets displaying diverse transcriptional states. During choroidal neovascularization, a typical hallmark of neovascular age-related macular degeneration (AMD), we recognized disease-specific macrophage subpopulations with distinct molecular signatures. Our results highlight the heterogeneity of myeloid subsets and their dynamics in the eye that provide new insights into the innate immune system in this organ which may offer new therapeutic targets for ophthalmological diseases.


Asunto(s)
Coroides/irrigación sanguínea , Ojo/inmunología , Macrófagos/inmunología , Células Mieloides/inmunología , Neovascularización Fisiológica/fisiología , Animales , Coroides/embriología , Biología Computacional , Simulación por Computador , Ojo/citología , Ojo/metabolismo , Femenino , Homeostasis/inmunología , Humanos , Inmunidad Innata/inmunología , Degeneración Macular/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Microglía/fisiología , Células Mieloides/metabolismo , Análisis de Secuencia de ARN , Análisis de la Célula Individual , Transcripción Genética/genética
2.
Ophthalmologica ; 247(2): 95-106, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38368867

RESUMEN

INTRODUCTION: The German Registry of central serous chorioretinopathy (CSC) collects data on CSC patients in a nationwide multicenter approach to analyze epidemiology, risk factors, clinical presentations, as well as diagnosis and treatment patterns. METHODS: In this multicenter cohort study, patients with CSC were enrolled in nine tertiary referral centers in Germany between January 2022 and June 2023. After consenting to the study, demographic data, risk factors, reported symptoms, best-corrected visual acuity (BCVA), funduscopic findings, disease severity, and diagnostic and treatment decisions were recorded and analyzed. RESULTS: A total of 539 eyes of 411 CSC patients were enrolled in this study including 308 males (75%) and 103 females (25%). Patients were predominantly of Caucasian origin and had a mean age of 55.5 years (IQR 41.0-70.0). 28% of eyes were classified as acute (<4 months duration) CSC, 28% as chronic (>4 months duration) CSC, 21% as inactive CSC, 11% as chronic atrophic CSC, and 12% as CSC with secondary CNV. 128 patients (31%) demonstrated bilateral CSC. The most common risk factors reported were psychological stress (52%), smoking (38%), arterial hypertension (38%), and a history of or current use of steroids (30%). Most frequently encountered symptoms included decreased visual acuity (76%), metamorphopsia (49%), relative scotoma (47%), blurred vision (19%), and dyschromatopsia (9%). The mean logMAR BCVA on initial examination was 0.2 (≈20/30, IQR 0.2-0.4) but showed significant variation with a tendency of lower BCVA in chronic cases. At the baseline visit, 74% of the overall cohort received no treatment, while 19% underwent local treatment and only 2% underwent systemic treatment. Of the local therapies, anti-VEGF injections were the most frequently performed procedure (33%, mainly for secondary CNV), followed by micropulse laser (28%), focal nonpulsed laser (23%), verteporfin photodynamic therapy (14%), and nonsteroidal anti-inflammatory eye drops (2%). Among intravitreal anti-VEGF agents, aflibercept was used most frequently, followed by bevacizumab and ranibizumab. CONCLUSION: This registry represents one of the largest cohorts of European patients with CSC to date. Patient age and the proportion of women were higher than expected and bilateral active disease was lower than anticipated, highlighting that neither age nor gender should be overemphasized when diagnosing CSC. Therapeutic interventions are heterogeneous and include verteporfin photodynamic therapy, micropulse laser, and anti-VEGF injections in case of secondary CNV.


Asunto(s)
Coriorretinopatía Serosa Central , Angiografía con Fluoresceína , Sistema de Registros , Tomografía de Coherencia Óptica , Agudeza Visual , Humanos , Coriorretinopatía Serosa Central/diagnóstico , Coriorretinopatía Serosa Central/epidemiología , Coriorretinopatía Serosa Central/terapia , Persona de Mediana Edad , Masculino , Femenino , Alemania/epidemiología , Anciano , Tomografía de Coherencia Óptica/métodos , Adulto , Angiografía con Fluoresceína/métodos , Factores de Riesgo , Fondo de Ojo , Estudios Retrospectivos , Incidencia , Estudios de Seguimiento , Retina/patología
3.
J Strength Cond Res ; 36(2): 469-477, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-31895287

RESUMEN

ABSTRACT: Giboin, L-S and Gruber, M. Neuromuscular fatigue induced by a mixed martial art training protocol. J Strength Cond Res 36(2): 469-477, 2022-Mixed martial arts (MMA) is a full-contact sport whose popularity and professionalism are rapidly growing. However, the specific physiological demands of this sport have been only scarcely studied so far, and especially the amount or type of neuromuscular fatigue induced by an MMA bout remains completely unknown. We estimated neuromuscular fatigue of knee extensors muscles during and after an MMA training protocol designed to simulate the physiological demands of MMA competition in competitive practitioners (n = 9) with isometric maximal voluntary force (MVF), potentiated muscle twitch at rest (Ptw), and voluntary activation (VA). Bayesian linear mixed models showed that the training protocol induced a reduction of MVF, Ptw, and VA. Although the largest reduction across time of VA was smaller than the largest reduction of Ptw, an effect of VA, but not of Ptw, was found on MVF variation. The training protocol induced neuromuscular fatigue, with a larger peripheral (Ptw) than central component (VA). However, despite the large decrease in Ptw, force production capacity was related only to VA, indicating that central control might play an important role in the compensation of the peripheral fatigue components estimated with Ptw. This central compensation can most probably prevent a too large loss of muscle force during the training protocol.


Asunto(s)
Artes Marciales , Fatiga Muscular , Teorema de Bayes , Electromiografía , Humanos , Contracción Isométrica , Rodilla , Músculo Esquelético
4.
Klin Monbl Augenheilkd ; 239(3): 308-312, 2022 Mar.
Artículo en Inglés, Alemán | MEDLINE | ID: mdl-33202433

RESUMEN

BACKGROUND: After preparation of a graft for Descemet membrane endothelial keratoplasty (DMEK), the diameter of the graft's scroll varies significantly. In particular, narrow scrolls may complicate DMEK surgery. In this study we investigated how temperature, osmolarity, and deswelling of the donor tissue influence scrolling diameter. MATERIAL AND METHODS: In this study we examined donor corneas that could not be used for transplantation. The diameter of the DMEK donor scrolls was measured after graft preparation by reflected light microscopy under different conditions: (1) The diameter of the roll was measured in Ringer's solution at temperatures of 5 °C, 24 °C and 35 °C. (2) To study the effect of different culture conditions we used 6% dextran-containing medium for 10 min, 20 min, 16 h and 24 h, and hyper- and hypoosmolar fluids (5% NaCl or aqua dest) for 5 min each. RESULTS: The median donors age was 62 years. The median endothelial cell density of the donor corneas was 1679 cells/mm2. The median diameter of the DMEK scroll was 1.35 mm in Ringer's solution at 24 °C (IQR, 1.04 - 1.89). In Ringer's solution at different temperatures, the scrolling diameter changed between 0.02 mm and 0.29 mm. The change in osmolarity resulted in a difference of 0.02 mm to 0.46 mm. Deswelling with dextran resulted in a change of scrolling diameter between 0.02 mm and 0.09 mm. SUMMARY: In this experimental case series, the diameter of the DMEK scroll did not change due to changes of temperature, osmolarity or deswelling. Influencing the graft's scroll to standardize and simplify the DMEK surgery remains an interesting goal for future studies.


Asunto(s)
Lámina Limitante Posterior , Queratoplastia Endotelial de la Lámina Limitante Posterior , Recuento de Células , Córnea/cirugía , Lámina Limitante Posterior/cirugía , Queratoplastia Endotelial de la Lámina Limitante Posterior/métodos , Endotelio Corneal/cirugía , Humanos , Persona de Mediana Edad , Concentración Osmolar , Temperatura
5.
Klin Monbl Augenheilkd ; 239(10): 1248-1258, 2022 Oct.
Artículo en Inglés, Alemán | MEDLINE | ID: mdl-34731899

RESUMEN

BACKGROUND: Globe ruptures are ophthalmological emergencies where the primary diagnosis using a slit lamp is often a challenge. OBJECTIVES: The retrospective case study aimed to characterise the predilection sites, the demographic profile and the causes of bursts due to blunt globe trauma. MATERIALS AND METHODS: The surgical plan of the Eye Centre of the Medical Centre (University of Freiburg) was electronically searched using the keyword "globe rupture" over a period of 18 years (2000 - 2018). This led to 350 hits, which were scrutinised by hand. 134 globe ruptures due to blunt globe trauma were then identified. RESULTS: The most common predilection sites were the upper nasal and the upper temporal paralimbal zones with 37 and 32% of the examined globe ruptures, respectively. The average age at the time of rupture was 60 (from 2 to 97) years. The median age was 62.5 years. 37% (49/134) of patients were female. The most frequent causes of accidents were falls (43%), "flying" wooden and metal objects (18%) and acts of violence (10%). CONCLUSIONS: Special attention should be paid to the upper paralimbal zone in the exploratory primary care of globe ruptures. If the rupture occurred due to "flying" wooden and metal objects, the posterior sclera burst most frequently. The epidemiological data suggest that targeted prevention against falls for individuals over 60 years and consistent wearing of protective eyewear when working with wood or metal could reduce the incidence of bulbar bursting. It was also noticeable that acts of violence were the third most frequent cause of rupture, although woman did not report that they were affected by this. Given the high occurrence of violence against women, shame and stigma may lead to an incorrect inquiry about the cause of the accident. This could be mitigated by training employees specifically to take a sensitive history.


Asunto(s)
Lesiones Oculares , Heridas no Penetrantes , Femenino , Humanos , Persona de Mediana Edad , Preescolar , Niño , Adolescente , Adulto Joven , Adulto , Anciano , Anciano de 80 o más Años , Masculino , Estudios Retrospectivos , Agudeza Visual , Rotura/complicaciones , Rotura/cirugía , Heridas no Penetrantes/diagnóstico , Heridas no Penetrantes/complicaciones , Lesiones Oculares/diagnóstico , Lesiones Oculares/epidemiología , Lesiones Oculares/cirugía
6.
Neuroimage ; 226: 117576, 2021 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-33221450

RESUMEN

Notwithstanding the apparent demands regarding fine motor skills that are required to perform in action video games, the motor nervous system of players has not been studied systematically. In the present study, we hypothesized to find differences in sensorimotor performance and corticospinal characteristics between action video game players (Players) and Controls. We tested sensorimotor performance in video games tasks and used transcranial magnetic stimulation (TMS) to measure motor map, input-output (IO) and short intra-cortical inhibition (SICI) curves in the first dorsal interosseous (FDI) muscle of Players (n = 18) and Control (n = 18). Players scored higher in performance tests and had stronger SICI and higher motor evoked potential (MEP) amplitudes. Multiple linear regressions showed that Players and Control differed with respect to their relation between reaction time and corticospinal excitability. However, we did not find different motor map topography or different IO curves for Players when compared to Controls. Action video game players showed an increased efficiency of motor cortical inhibitory and excitatory neural networks. Players also showed a different relation of MEPs with reaction time. The present study demonstrates the potential of action video game players as an ideal population to study the mechanisms underlying visuomotor performance and sensorimotor learning.


Asunto(s)
Potenciales Evocados Motores/fisiología , Corteza Motora/fisiología , Inhibición Neural/fisiología , Desempeño Psicomotor/fisiología , Juegos de Video , Adulto , Estudios de Casos y Controles , Corteza Cerebral/fisiología , Electromiografía , Femenino , Mano , Humanos , Masculino , Músculo Esquelético , Tiempo de Reacción , Estimulación Magnética Transcraneal , Adulto Joven
7.
Am J Pathol ; 190(8): 1632-1642, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32339498

RESUMEN

Recent studies deciphering the transcriptional profile of choroidal neovascularization (CNV) in body donor eyes with neovascular age-related macular degeneration are limited by the time span from death to preservation and the associated 5'-RNA degradation. This study therefore used CNV and control specimens that were formalin-fixed and paraffin-embedded immediately after surgical extraction and analyzed them by a 3'-RNA sequencing approach. Transcriptome profiles were analyzed to estimate content of immune and stromal cells and to define disease-associated gene signatures by using statistical and bioinformatics methods. This study identified 158 differentially expressed genes (DEGs) that were significantly increased in CNV compared with control tissue. Cell type enrichment analysis revealed a diverse cellular landscape with an enrichment of endothelial cells, macrophages, T cells, and natural killer T cells in the CNV. Gene ontology enrichment analysis found that DEGs contributed to blood vessel development, extracellular structure organization, response to wounding, and several immune-related terms. The S100 calcium-binding proteins A8 (S100A8) and A9 (S100A9) emerged among the top DEGs, as confirmed by immunohistochemistry on CNV tissue and protein analysis of vitreous samples. This study provides a high-resolution RNA-sequencing-based transcriptional signature of human CNV, characterizes its compositional pattern of immune and stromal cells, and reveals S100A8/A9 to be a novel biomarker and promising target for therapeutics and diagnostics directed at age-related macular degeneration.


Asunto(s)
Neovascularización Coroidal/diagnóstico , Complejo de Antígeno L1 de Leucocito/metabolismo , Degeneración Macular/diagnóstico , Anciano , Anciano de 80 o más Años , Biomarcadores/metabolismo , Neovascularización Coroidal/metabolismo , Células Endoteliales/metabolismo , Femenino , Humanos , Macrófagos/metabolismo , Degeneración Macular/metabolismo , Masculino , Transcriptoma
8.
Mol Cell Proteomics ; 18(9): 1880-1892, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31235637

RESUMEN

Mass spectrometry based proteomics is the method of choice for quantifying genome-wide differential changes of protein expression in a wide range of biological and biomedical applications. Protein expression changes need to be reliably derived from many measured peptide intensities and their corresponding peptide fold changes. These peptide fold changes vary considerably for a given protein. Numerous instrumental setups aim to reduce this variability, whereas current computational methods only implicitly account for this problem. We introduce a new method, MS-EmpiRe, which explicitly accounts for the noise underlying peptide fold changes. We derive data set-specific, intensity-dependent empirical error fold change distributions, which are used for individual weighing of peptide fold changes to detect differentially expressed proteins (DEPs).In a recently published proteome-wide benchmarking data set, MS-EmpiRe doubles the number of correctly identified DEPs at an estimated FDR cutoff compared with state-of-the-art tools. We additionally confirm the superior performance of MS-EmpiRe on simulated data. MS-EmpiRe requires only peptide intensities mapped to proteins and, thus, can be applied to any common quantitative proteomics setup. We apply our method to diverse MS data sets and observe consistent increases in sensitivity with more than 1000 additional significant proteins in deep data sets, including a clinical study over multiple patients. At the same time, we observe that even the proteins classified as most insignificant by other methods but significant by MS-EmpiRe show very clear regulation on the peptide intensity level. MS-EmpiRe provides rapid processing (< 2 min for 6 LC-MS/MS runs (3 h gradients)) and is publicly available under github.com/zimmerlab/MS-EmpiRe with a manual including examples.


Asunto(s)
Espectrometría de Masas/métodos , Péptidos/análisis , Proteoma/análisis , Proteómica/métodos , Programas Informáticos , Enfermedad de Alzheimer/metabolismo , Benchmarking , Bases de Datos Factuales , Francisella/metabolismo , Proteínas Fúngicas/análisis , Células HeLa , Humanos , Enfermedad de Parkinson/metabolismo , Proteínas de Plantas/análisis , Reproducibilidad de los Resultados , Relación Señal-Ruido
9.
BMC Geriatr ; 21(1): 257, 2021 04 17.
Artículo en Inglés | MEDLINE | ID: mdl-33865308

RESUMEN

BACKGROUND: High prevalence rates have been reported for physical inactivity, mobility limitations, and falls in older adults. Home-based exercise might be an adequate means to increase physical activity by improving health- (i.e., muscle strength) and skill-related components of physical fitness (i.e., balance), particularly in times of restricted physical activity due to pandemics. OBJECTIVE: The objective of this study was to examine the effects of home-based balance exercises conducted during daily tooth brushing on measures of balance and muscle strength in healthy older adults. METHODS: Fifty-one older adults were randomly assigned to a balance exercise group (n = 27; age: 65.1 ± 1.1 years) or a passive control group (n = 24; age: 66.2 ± 3.3 years). The intervention group conducted balance exercises over a period of eight weeks twice daily for three minutes each during their daily tooth brushing routine. Pre- and post-intervention, tests were included for the assessment of static steady-state balance (i.e., Romberg test), dynamic steady-state balance (i.e., 10-m single and dual-task walk test using a cognitive and motor interference task), proactive balance (i.e., Timed-Up-and-Go Test [TUG], Functional-Reach-Test [FRT]), and muscle strength (i.e., Chair-Rise-Test [CRT]). RESULTS: Irrespective of group, the statistical analysis revealed significant main effects for time (pre vs. post) for dual-task gait speed (p < .001, 1.12 ≤ d ≤ 2.65), TUG (p < .001, d = 1.17), FRT (p = .002, d = 0.92), and CRT (p = .002, d = 0.94) but not for single-task gait speed and for the Romberg-Test. No significant group × time interactions were found for any of the investigated variables. CONCLUSIONS: The applied lifestyle balance training program conducted twice daily during tooth brushing routines appears not to be sufficient in terms of exercise dosage and difficulty level to enhance balance and muscle strength in healthy adults aged 60-72 years. Consequently, structured balance training programs using higher exercise dosages and/or more difficult balance tasks are recommended for older adults to improve balance and muscle strength.


Asunto(s)
Equilibrio Postural , Cepillado Dental , Anciano , Ejercicio Físico , Terapia por Ejercicio , Humanos , Fuerza Muscular , Estudios de Tiempo y Movimiento
10.
Eur J Appl Physiol ; 121(7): 2015-2026, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33811556

RESUMEN

PURPOSE: Spaceflight impairs physical capacity. Here we assessed the protective effect of artificial gravity (AG) on aerobic exercise capacity and muscle function during bed rest, a spaceflight analogue. METHODS: 24 participants (33 ± 9 years, 175 ± 9 cm, 74 ± 10 kg, 8 women) were randomly allocated to one of three groups: continuous AG (cAG), intermittent AG (iAG) or control (CTRL). All participants were subjected to 60 days of six-degree head-down tilt bed rest, and subjects of the intervention groups completed 30 min of centrifugation per day: cAG continuously and iAG for 6 × 5 min, with an acceleration of 1g at the center of mass. Physical capacity was assessed before and after bed rest via maximal voluntary contractions, cycling spiroergometry, and countermovement jumps. RESULTS: AG had no significant effect on aerobic exercise capacity, flexor muscle function and isometric knee extension strength or rate of force development (RFD). However, AG mitigated the effects of bed rest on jumping power (group * time interaction of the rmANOVA p < 0.001; iAG - 25%, cAG - 26%, CTRL - 33%), plantar flexion strength (group * time p = 0.003; iAG - 35%, cAG - 31%, CTRL - 48%) and plantar flexion RFD (group * time p = 0.020; iAG - 28%, cAG - 12%, CTRL - 40%). Women showed more pronounced losses than men in jumping power (p < 0.001) and knee extension strength (p = 0.010). CONCLUSION: The AG protocols were not suitable to maintain aerobic exercise capacity, probably due to the very low cardiorespiratory demand of this intervention. However, they mitigated some losses in muscle function, potentially due to the low-intensity muscle contractions during centrifugation used to avoid presyncope.


Asunto(s)
Reposo en Cama , Tolerancia al Ejercicio/fisiología , Gravedad Alterada , Adulto , Ergometría , Femenino , Inclinación de Cabeza , Humanos , Masculino , Contracción Muscular/fisiología , Factores de Tiempo
11.
J Physiol ; 598(10): 1943-1963, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32115702

RESUMEN

KEY POINTS: The spinal cord is an important contributor to motor learning It remains unclear whether short-term spinal cord adaptations are general or task-specific Immediately after task acquisition, neural adaptations were not specific to the trained task (i.e. were general) Twenty-four hours after acquisition, neural adaptations appeared to be task-specific The neural reorganization and generalization of spinal adaptations appears to be time-dependent. ABSTRACT: Spinal cord plasticity is an important contributor of motor learning in humans, although its mechanisms are still poorly documented. In particular, it remains unclear whether short-term spinal adaptations are general or task-specific. As a marker of neural changes that are observable at spinal level, we measured the Hoffmann reflex (H-reflex) amplitude in the soleus muscle of 18 young healthy human adults before, immediately after (acquisition), and 24 h after (retention) the learning of a skilled task (i.e. one-legged stance on a tilt board). H-reflexes were elicited 46 ± 30 ms before touching the tilt board. Additionally, and at the same time points, we measured the H-reflex with the subject sitting at rest and when performing an unskilled and untrained task (i.e. one-legged stance on the floor). After task acquisition, there was a decrease of the H-reflex amplitude measured at rest but not during the skilled or the unskilled task. At retention, there was a decrease of the H-reflex when measured during the skilled task but not during the unskilled task or at rest. Performance increase was not associated with changes in the H-reflex amplitude. After the acquisition of a new skilled task, spinal changes appeared to be general (i.e. observable at rest). However, 24 h after, these changes were task-specific (i.e. observable only during performance of the trained task). These results imply that skill training induces a time-dependent reorganization of the modulation of spinal networks, which possibly reflects a time-dependent optimization of the feedforward motor command.


Asunto(s)
Reflejo H , Músculo Esquelético , Adulto , Estimulación Eléctrica , Electromiografía , Humanos , Médula Espinal
12.
Exp Brain Res ; 238(2): 465-476, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31955233

RESUMEN

Studies investigating balance control often use external perturbations to probe the system. These perturbations can be administered as randomized, pseudo-randomized, or predictable sequences. As predictability of a given perturbation can affect balance performance, the way those perturbations are constructed may affect the results of the experiments. In the present study, we hypothesized that subjects are able to adapt to short, rhythmic support surface tilt stimuli, but not to long pseudo-random stimuli. 19 subjects were standing with eyes closed on a servo-controlled platform tilting about the ankle joint axis. Pre and post to the learning intervention, pseudo-random tilt sequences were applied. For the learning phase, a rhythmic and easy-to-memorize 8-s long sequence was applied 75 times, where subjects were instructed to stand as still as possible. Body kinematics were measured and whole body center of mass sway was analyzed. Results showed reduced sway and less forward lean of the body across the learning phase. The sway reductions were similar for stimulus and non-stimulus frequencies. Surprisingly, for the pseudo-random sequences, comparable changes were found from pre- to post-tests. In summary, results confirmed that considerable adaptations exist when exposing subjects to an 8-s long rhythmic perturbation. No indications of predictions of the learning tilt sequence were found, since similar changes were also observed in response to pseudo-random sequences. We conclude that changes in body sway responses following 75 repetitions of an 8-s long rhythmic tilt sequence are due to adaptations in the dynamics of the control mechanism (presumably stiffness).


Asunto(s)
Adaptación Fisiológica/fisiología , Articulación del Tobillo/fisiología , Equilibrio Postural/fisiología , Postura/fisiología , Adulto , Fenómenos Biomecánicos/fisiología , Femenino , Humanos , Masculino
13.
Neuroimage ; 202: 116061, 2019 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-31374329

RESUMEN

Humans develop posture and balance control during childhood. Interestingly, adults can also learn to master new complex balance tasks, but the underlying neural mechanisms are not fully understood yet. Here, we combined broad scale brain connectivity fMRI at rest and spinal excitability measurements during movement. Six weeks of slackline training improved the capability to walk on a slackline which was paralleled by functional connectivity changes in brain regions associated with posture and balance control and by task-specific changes of spinal excitability. Importantly, the performance of trainees was not better than control participants in a different, untrained balance task. In conclusion, slackline training induced large-scale neuroplasticity which solely transferred into highly task specific performance improvements.


Asunto(s)
Encéfalo/fisiología , Conectoma , Reflejo H/fisiología , Aprendizaje/fisiología , Actividad Motora/fisiología , Músculo Esquelético/fisiología , Plasticidad Neuronal/fisiología , Equilibrio Postural/fisiología , Desempeño Psicomotor/fisiología , Médula Espinal/fisiología , Transferencia de Experiencia en Psicología/fisiología , Adulto , Encéfalo/diagnóstico por imagen , Electromiografía , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Adulto Joven
14.
Phys Rev Lett ; 122(10): 108002, 2019 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-30932679

RESUMEN

We study experimentally the origin of heterogeneous dynamics in strongly driven glass-forming systems. Thereto, we apply a well-defined force with a laser line trap on individual colloidal polystyrene probe particles seeded in an emulsion glass composed of droplets of the same size. Fluid and glass states can be probed. We monitor the trajectories of the probe and measure displacements and their distributions. Our experiments reveal intermittent dynamics around a depinning transition at a threshold force. For smaller forces, linear response connects mean displacement, and quiescent mean squared displacement. Mode coupling theory calculations rationalize the observations.

15.
Eur J Appl Physiol ; 119(5): 1149-1156, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30783734

RESUMEN

PURPOSE: High-intensity interval training (HIT) has been shown to be an effective endurance training method. However, most HIT research has been conducted on running and cycling. The aim of this study was to assess the suitability of intermittent exercises such as jumps as a type of HIT. METHODS: Respiratory gases, heart rate and ground reaction forces were recorded for 21 participants (age 25 ± 4 years, mass 73 ± 12 kg, 13 male) during 5 distinct jump sessions on different days that varied with respect to the rest durations in between series (0, 15 or 30 s) and in between jumps (0, 1 or 2 s). Blood lactate was determined 3 min after the last series. Prior to the first session, maximal jump height as well as V'O2max during cycling was recorded. RESULTS: Peak oxygen uptake and heart rate were nearly maximal during all five jump sessions (87-99% of V'O2max, 96-98% of maximal heart rate). The time spent at more than 90% of V'O2max (1-43% of the total session duration), average jump height (34-82% of maximal jump height) and lactate accumulation (4-9 mmol/l) differed between jump sessions, mainly depending on the rest interval between jumps (p < 0.001, rmANOVA between sessions with different rest intervals between jumps). CONCLUSION: With short rest intervals, jumping elicited comparable acute responses as reported for running or cycling HIT. Thus, training programs using intermittent exercises should elicit similar adaptations as other forms of HIT, provided the rest intervals are sufficiently short. Heart rate might be of limited value when comparing different types of HIT.


Asunto(s)
Frecuencia Cardíaca , Entrenamiento de Intervalos de Alta Intensidad/métodos , Ácido Láctico/sangre , Consumo de Oxígeno , Adulto , Femenino , Entrenamiento de Intervalos de Alta Intensidad/efectos adversos , Humanos , Masculino
16.
Int J Mol Sci ; 20(12)2019 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-31248182

RESUMEN

Several studies indicate that acute exercise induces DNA damage, whereas regular exercise increases DNA repair kinetics. Although the molecular mechanisms are not completely understood, the induction of endogenous reactive oxygen species (ROS) during acute exhaustive exercise due to metabolic processes might be responsible for the observed DNA damage, while an adaptive increase in antioxidant capacity due to regular physical activity seems to play an important protective role. However, the protective effect of physical activity on exogenously induced DNA damage in human immune cells has been poorly investigated. We asked the question whether individuals with a high aerobic capacity would have an enhanced response to radiation-induced DNA damage. Immune cells are highly sensitive to radiation and exercise affects lymphocyte dynamics and immune function. Therefore, we measured endogenous and radiation-induced DNA strand breaks and poly (ADP-ribose) polymerase-1 (PARP1) activity in peripheral blood mononuclear cells (PBMCs) from endurance-trained (maximum rate of oxygen consumption measured during incremental exercise V'O2max > 55 mL/min/kg) and untrained (V'O2max < 45 mL/min/kg) young healthy male volunteers before and after exhaustive exercise. Our results indicate that: (i) acute exercise induces DNA strand breaks in lymphocytes only in untrained individuals, (ii) following acute exercise, trained individuals repaired radiation-induced DNA strand breaks faster than untrained individuals, and (iii) trained subjects retained a higher level of radiation-induced PARP1 activity after acute exercise. The results of the present study indicate that increased aerobic fitness can protect immune cells against radiation-induced DNA strand breaks.


Asunto(s)
Reparación del ADN , Ejercicio Físico , Linfocitos/metabolismo , Linfocitos/efectos de la radiación , Poli(ADP-Ribosa) Polimerasa-1/metabolismo , Radiación Ionizante , Daño del ADN , Humanos , Leucocitos Mononucleares/metabolismo , Leucocitos Mononucleares/efectos de la radiación , Aptitud Física
17.
J Neurosci Res ; 96(9): 1600-1609, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29696675

RESUMEN

Transcranial direct current stimulation (tDCS) has the capacity to enhance force output during a short-lasting maximal voluntary contraction (MVC) as well as during a long-lasting submaximal voluntary contraction until task failure. However, its effect on an intermittent maximal effort is not known. We hypothesized that anodal tDCS applied during or before a maximal fatigue task increases the amplitude of maximal voluntary contraction (aMVC) and voluntary activation (VA) in young healthy male participants. We measured VA, potentiated twitch at rest (Ptw), root mean square electromyogram (EMG), and aMVC during a fatiguing task that consisted of 35 × 5 s MVC of knee extensors and was performed during tDCS or 10 min after the end of tDCS (sham, anodal, or cathodal treatments). No effect of tDCS was detected on the first MVC but, when compared to sham tDCS, both anodal tDCS and cathodal tDCS reduced aMVC when tDCS was applied during the task (p < .001) and only anodal tDCS reduced aMVC when applied 10 min before the task (p = .03). The reductions in aMVC were accompanied by reductions in EMG of M. vastus lateralis for both tDCS treatments as well as in Ptw only during anodal tDCS and in VA only during cathodal tDCS. Both cathodal tDCS and anodal tDCS impaired force production during an intermittent fatiguing MVC task. The detrimental effects were stronger when tDCS was applied during the task. Here, cathodal and anodal tDCS specifically affected Ptw and VA indicating different underlying mechanisms.


Asunto(s)
Corteza Cerebral/fisiología , Fatiga/fisiopatología , Contracción Muscular , Músculo Cuádriceps/fisiología , Estimulación Transcraneal de Corriente Directa , Adulto , Estimulación Eléctrica , Humanos , Masculino , Adulto Joven
18.
Bioinformatics ; 30(21): 3128-30, 2014 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-25064567

RESUMEN

MOTIVATION: Recent breakthroughs in protein residue-residue contact prediction have made reliable de novo prediction of protein structures possible. The key was to apply statistical methods that can distinguish direct couplings between pairs of columns in a multiple sequence alignment from merely correlated pairs, i.e. to separate direct from indirect effects. Two classes of such methods exist, either relying on regularized inversion of the covariance matrix or on pseudo-likelihood maximization (PLM). Although PLM-based methods offer clearly higher precision, available tools are not sufficiently optimized and are written in interpreted languages that introduce additional overheads. This impedes the runtime and large-scale contact prediction for larger protein families, multi-domain proteins and protein-protein interactions. RESULTS: Here we introduce CCMpred, our performance-optimized PLM implementation in C and CUDA C. Using graphics cards in the price range of current six-core processors, CCMpred can predict contacts for typical alignments 35-113 times faster and with the same precision as the most accurate published methods. For users without a CUDA-capable graphics card, CCMpred can also run in a CPU mode that is still 4-14 times faster. Thanks to our speed-ups (http://dictionary.cambridge.org/dictionary/british/speed-up) contacts for typical protein families can be predicted in 15-60 s on a consumer-grade GPU and 1-6 min on a six-core CPU. AVAILABILITY AND IMPLEMENTATION: CCMpred is free and open-source software under the GNU Affero General Public License v3 (or later) available at https://bitbucket.org/soedinglab/ccmpred.


Asunto(s)
Proteínas/química , Alineación de Secuencia/métodos , Análisis de Secuencia de Proteína , Programas Informáticos , Mutación , Proteínas/clasificación , Proteínas/genética , Homología de Secuencia de Aminoácido
19.
Eur J Appl Physiol ; 115(5): 1107-15, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25549788

RESUMEN

PURPOSE: Extensive evidence exists that regular physical exercise offers neuroplastic benefits to the brain. In this study, exercise-specific effects on motor cortex plasticity were compared between 15 skilled and 15 endurance trained athletes and 8 controls. METHODS: Plasticity was tested with a paired associative stimulation (PAS) protocol. PAS is a non-invasive stimulation method developed to induce bidirectional changes in the excitability of the cortical projections to the target muscles. Motor cortex excitability was assessed by motor-evoked potentials (MEPs) in the task-relevant soleus muscle, elicited with transcranial magnetic stimulation, before and following PAS. To test for changes at the spinal level, soleus short latency stretch reflexes (SLSR) were elicited before and after PAS. RESULTS: PAS induced a significant (76 ± 83 %) increase in MEP amplitude in the skill group, without significant changes in the endurance (-7 ± 35 %) or control groups (21 ± 30 %). Baseline MEP/post MEP ratio was significantly different between the skill and endurance groups. SLSR remained unchanged after the PAS intervention. CONCLUSION: The possible reason for differential motor cortex plasticity in skill and endurance groups is likely related to the different training-induced adaptations. The findings of the current study suggest that long-term skill training by skill group induced preferable adaptations in the task-related areas of the motor cortex because increased plasticity is known to enhance motor learning.


Asunto(s)
Atletas , Potenciales Evocados Motores/fisiología , Corteza Motora/fisiología , Plasticidad Neuronal/fisiología , Adulto , Electromiografía , Femenino , Humanos , Masculino , Músculo Esquelético/fisiología , Estimulación Magnética Transcraneal , Adulto Joven
20.
Arch Phys Med Rehabil ; 95(10): 1803-9, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24823959

RESUMEN

OBJECTIVE: To assess the effectiveness of and adherence to an exergame balance training program with additional postural demands in patients with multiple sclerosis (MS). DESIGN: Matched controlled trial, assessment of balance before and after different balance training programs, and adherence to home-based balance exercise in the 6 months after the training. SETTING: A neurorehabilitation facility and center for MS. PARTICIPANTS: Patients with balance problems (N=70) matched into 1 of the training groups according to age as well as balance and gait performance in 4 tests. Nine patients dropped out of the study because of scheduling problems. The mean age of the 61 remaining participants was 47±9 years, and their Expanded Disability Status Scale score was 3±1. INTERVENTIONS: Three weeks of (1) conventional balance training (control), (2) exergame training (playing exergames on an unstable platform), or (3) single-task (ST) exercises on the unstable platform. MAIN OUTCOME MEASURES: Test scores in balance tests and gait analyses under ST and dual-task (DT) situations. Furthermore, in the 6 months after the rehabilitation training, the frequency and type of balance training were assessed by using questionnaires. RESULTS: All 3 groups showed significantly improved balance and gait scores. Only the exergame training group showed significantly higher improvements in the DT condition of the gait test than in the ST condition. Adherence to home-based balance training differed significantly between groups (highest adherence in the exergame training group). CONCLUSIONS: Playing exergames on an unstable surface seems to be an effective way to improve balance and gait in patients with MS, especially in DT situations. The integration of exergames seems to have a positive effect on adherence and is thus potentially beneficial for the long-term effectiveness of rehabilitation programs.


Asunto(s)
Terapia por Ejercicio/métodos , Marcha/fisiología , Esclerosis Múltiple/rehabilitación , Cooperación del Paciente , Equilibrio Postural/fisiología , Juegos de Video , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Esclerosis Múltiple/fisiopatología
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