Effects of a primary rehabilitation programme on arterial vascular adaptations in an individual with paraplegia

AbstractObjectiveEvaluation of the effects of 6 weeks of wheelchair endurance training on arterial stiffness in an individual with paraplegia.MethodsA 22-year-old male patient with complete (ASIA A) paraplegia (T11) was tested before and after training (30minutes three times per week). Physical performance and cardiorespiratory response were evaluated during a maximal progressive test. Heart rate (HR), blood pressure, stroke volume and arterial carotid–wrist and carotid–ankle pulse wave velocity (PWV) were measured at rest.ResultsMaximal responses registered (maximal tolerated power, V˙O2 peak) during the exercise test were increased after training. At rest, HR as PWV decreased, whereas cardiac output and blood pressure remained constant.ConclusionContinuous exposure of the subject to a repeated high intensity exercise bout for 6 weeks elevated fitness level. Such a regular practice might also constitute a major way to trigger vascular remodelling beyond to the trained body part

Does Characterizing Global Running Pattern Help to Prescribe Individualized Strength Training in Recreational Runners?

This study aimed to determine if concurrent endurance and strength training that matches the global running pattern would be more effective in increasing running economy (RE) than non-matched training. The global running pattern of 37 recreational runners was determined using the Volodalen <sup>®</sup> method as being aerial (AER) or terrestrial (TER). Strength training consisted of endurance running training and either plyometric (PLY) or dynamic weight training (DWT). Runners were randomly assigned to a matched (n = 18; DWT for TER, PLY for AER) or non-matched (n = 19; DWT for AER, PLY for TER) 8 weeks concurrent training program. RE, maximal oxygen uptake V̇O <sub>2</sub> max) and peak treadmill speed at V̇O <sub>2</sub> max (PTS) were measured before and after the training intervention. None of the tested performance related variables depicted a significant group effect or interaction effect between training and grouping (p ≥ 0.436). However, a significant increase in RE, V̇O <sub>2</sub> max, and PTS (p ≤ 0.003) was found after the training intervention. No difference in number of responders between matched and non-matched groups was observed for any of the performance related variables (p ≥ 0.248). In recreational runners, prescribing PLT or DWT according to the global running pattern of individuals, in addition to endurance training, did not lead to greater improvements in RE

Investigation of finger reflectance photoplethysmography in volunteers undergoing a local sympathetic stimulation

Optical sensors used in clinical applications have gained great popularity over the last few decades, especially the photoplethysmographic (PPG) technique used in estimating arterial blood oxygen saturation in the well-known medical devices called pulse oximeters. In this study we investigate the photoplethysmogram further in an effort to understand its origin better, as there is a significant void in the current knowledge on the PPG quantitative measurement. The photoplethysmographic signal provides a heart rhythm pulsating AC component, and a non-pulsating DC component. The signal is commonly believed to originate from tissue volume changes only and hasn't been investigated intensively. This in vivo study examines the source of the PPG signal in relation to pulse amplitude and pulse rhythm while volunteers undergo a right hand ice immersion. It was found that the PPG signal is sensitive in detecting the sympathetic stimulation which corresponds to volumetric and heart rate changes. During the immersion, AC pulse amplitudes (PA) from both hands decreased significantly, while DC levels increased significantly in the right hand and non-significantly in the left hand. Also, a significant decrease in the pulse repetition time (PRT) was observed. Using blood pressure-flow theories, these results suggest that there are possibly other factors in the blood flow regulation that alter the blood optical density which contributes to the detected signal. Further studies need to investigate PPGs in relation to blood optical density and the dynamics of the pulsatile flow effects besides volumetric changes. Such investigations might explore further applications of the PPG in medicine

Symptoms of anxiety and depression are related to cardiovascular responses to active, but not passive, coping tasks

Objective: Anxiety and depression have been linked to blunted blood pressure (BP) and heart rate (HR) reactions to mental stress tests; however, most studies have not included indices of underlying hemodynamics nor multiple stress tasks. This study sought to examine the relationships of anxiety and depression with hemodynamic responses to acute active and passive coping tasks. Methods: A total of 104 participants completed the Hospital Anxiety and Depression Scales and mental arithmetic, speech, and cold pressor tasks while BP, HR, total peripheral resistance, and cardiac output (CO) were assessed. Results: After adjustment for traditional risk factors and baseline cardiovascular activity, depression scores were negatively associated with systolic BP, HR, and CO responses to the mental arithmetic task, while anxiety scores were inversely related to the systolic BP response to mental arithmetic. Conclusion: High anxiety or depression scores appear to be associated with blunted cardiac reactions to mental arithmetic (an active coping task), but not to the cold pressor test or speech tasks. Future research should further examine potential mechanisms and longitudinal pathways relating depression and anxiety to cardiovascular reactivity

Sprint start kinetics of amputee and non-amputee sprinters

The purpose of this study was to explore the relationship between the forces applied to the starting blocks and the start performances (SPs) of amputee sprinters (ASs) and non-amputee sprinters (NASs). SPs of 154 male and female NASs (100-m personal records [PRs], 9.58–14.00 s) and 7 male ASs (3 unilateral above knee, 3 unilateral below knee, 1 bilateral below knee; 100 m PRs, 11.70–12.70 s) with running specific prostheses (RSPs) were analysed during full-effort sprint starts using instrumented starting blocks that measured the applied forces in 3D. Using the NAS dataset and a combination of factor analysis and multiple regression techniques, we explored the relationship between force characteristics and SP (quantified by normalized average horizontal block power). Start kinetics were subsequently compared between ASs and NASs who were matched based on their absolute 100 m PR and their 100 m PR relative to the world record in their starting class. In NASs, 86% of the variance in SP was shared with five latent factors on which measured parameters related to force application to the rear and front blocks and the respective push-off directions in the sagittal plane of motion were loaded. Mediolateral force application had little influence on SP. The SP of ASs was significantly reduced compared to that of NASs matched on the basis of relative 100-m PR (−33.8%; d = 2.11, p < 0.001), while a non-significant performance reduction was observed when absolute 100-m PRs were used (−17.7%; d = 0.79, p = 0.09). These results are at least partially explained by the fact that force application to the rear block was clearly impaired in the affected legs of ASs

The effect of water immersion on short-latency somatosensory evoked potentials in human

<p>Abstract</p> <p>Background</p> <p>Water immersion therapy is used to treat a variety of cardiovascular, respiratory, and orthopedic conditions. It can also benefit some neurological patients, although little is known about the effects of water immersion on neural activity, including somatosensory processing. To this end, we examined the effect of water immersion on short-latency somatosensory evoked potentials (SEPs) elicited by median nerve stimuli. Short-latency SEP recordings were obtained for ten healthy male volunteers at rest in or out of water at 30°C. Recordings were obtained from nine scalp electrodes according to the 10-20 system. The right median nerve at the wrist was electrically stimulated with the stimulus duration of 0.2 ms at 3 Hz. The intensity of the stimulus was fixed at approximately three times the sensory threshold.</p> <p>Results</p> <p>Water immersion significantly reduced the amplitudes of the short-latency SEP components P25 and P45 measured from electrodes over the parietal region and the P45 measured by central region.</p> <p>Conclusions</p> <p>Water immersion reduced short-latency SEP components known to originate in several cortical areas. Attenuation of short-latency SEPs suggests that water immersion influences the cortical processing of somatosensory inputs. Modulation of cortical processing may contribute to the beneficial effects of aquatic therapy.</p> <p>Trial Registration</p> <p>UMIN-CTR (UMIN000006492)</p

Bilayer-spanning DNA nanopores with voltage-switching between open and closed state.

Membrane-spanning nanopores from folded DNA are a recent example of biomimetic man-made nanostructures that can open up applications in biosensing, drug delivery, and nanofluidics. In this report, we generate a DNA nanopore based on the archetypal six-helix-bundle architecture and systematically characterize it via single-channel current recordings to address several fundamental scientific questions in this emerging field. We establish that the DNA pores exhibit two voltage-dependent conductance states. Low transmembrane voltages favor a stable high-conductance level, which corresponds to an unobstructed DNA pore. The expected inner width of the open channel is confirmed by measuring the conductance change as a function of poly(ethylene glycol) (PEG) size, whereby smaller PEGs are assumed to enter the pore. PEG sizing also clarifies that the main ion-conducting path runs through the membrane-spanning channel lumen as opposed to any proposed gap between the outer pore wall and the lipid bilayer. At higher voltages, the channel shows a main low-conductance state probably caused by electric-field-induced changes of the DNA pore in its conformation or orientation. This voltage-dependent switching between the open and closed states is observed with planar lipid bilayers as well as bilayers mounted on glass nanopipettes. These findings settle a discrepancy between two previously published conductances. By systematically exploring a large space of parameters and answering key questions, our report supports the development of DNA nanopores for nanobiotechnology.The SH lab is supported by the Leverhulme Trust (RPG-170), UCL Chemistry, EPSRC (Institutional Sponsorship Award), the National Physical Laboratory, and Oxford Nanopore Technologies. KG acknowledges funding from the Winton Program of Physics for Sustainability, Gates Cambridge and the Oppenheimer Trust. UFK was supported by an ERC starting grant #261101.This is the final version of the article. It was first published by ACS under the ACS AuthorChoice license at http://dx.doi.org/10.1021/nn5039433 This permits copying and redistribution of the article or any adaptations for non-commercial purposes