Κυριακή, 11 Δεκεμβρίου 2016

Mosaicism in health and disease — clones picking up speed

Many genetic studies focus on germline-inherited genomic variation. However, there is increasing realization that mutations occurring during our lifetime are so frequent and pervasive that, in all likelihood, no two of our cells are truly genetically identical. In this Review, the authors describe the detection, molecular nature and dynamics of this under-appreciated post-zygotic variation, and discuss the implications for normal human physiology and disease.

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The age dependent association between aortic pulse wave velocity and telomere length

Abstract

Introduction: Ageing is associated with marked large artery stiffening. Telomere shortening, a marker of cellular ageing, is linked with arterial stiffening. However, the results of existing studies are inconsistent, possibly because of the confounding influence of variable exposure to cardiovascular (CV) risk factors. Therefore, we investigated the relationship between telomere length (TL) and aortic stiffness in well-characterised, younger and older healthy adults, pre-selected on the basis of having either low or high aortic pulse wave velocity (aPWV), a robust measure of aortic stiffness. Methods: Demographic, haemodynamic and biochemical data were drawn from participants in the Anglo-Cardiff Collaborative Trial. Two age groups with an equal gender ratio were examined: those < 30 years (younger) or > 50 years (older). Separately for each age group and gender, DNA samples representing the highest (n = 125) and lowest (n = 125) extremes of aPWV (adjusted for blood pressure) were selected for analysis of leukocyte TL. Ultimately, this yielded complete phenotypic data on 904 individuals. Results: In younger subjects, TL was significantly shorter in those with high aPWV versus those low aPWV (P = 0.017). In contrast, in older subjects, TL was significantly longer in those with high aPWV (P = 0.001). Age significantly modified the relationship between aPWV and TL (P < 0.001). Discussion: Age modifies the relationship between aPWV and TL. Differential relationships are observed between aPWV and TL, with an inverse association in younger individuals and a positive association in older individuals. The links between cellular and vascular ageing reflect a complex interaction between genetic and environmental factors acting over the life-course.

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Effects of Overground Locomotor Training on Walking Performance in Chronic Cervical Motor-Incomplete Spinal Cord Injury: A Pilot Study

Publication date: Available online 11 December 2016
Source:Archives of Physical Medicine and Rehabilitation
Author(s): Jared M. Gollie, Andrew A. Guccione, Gino S. Panza, Peter Y. Jo, Jeffrey E. Herrick
ObjectiveTo determine the effects of a novel overground locomotor training (OLT) program on walking performance in people with chronic cervical motor-incomplete spinal cord injury (iSCI).DesignBefore-After Pilot Study.SettingHuman performance research laboratory.ParticipantsAdults (n=6; age>18 years) with chronic cervical iSCI C & D according to the American Spinal Injury Association Impairment Scale (AIS).InterventionOLT included two 90-minute sessions per week for 12-15 weeks. Training sessions alternated between uniplanar and multiplanar stepping patterns. Each session was comprised of five segments: joint mobility; volitional muscle activation; task-isolation; task-integration; activity rehearsal.Main Outcome MeasuresOverground walking speed, oxygen consumption (VO2), carbon dioxide production (VCO2).ResultsOLT increased overground walking speed (0.36±0.20 vs 0.51±0.24 m·s; P<0.001, d=0.68). Significant decreases in VO2 (6.6±1.3 vs 5.7±1.4 ml·kg·min; P=0.038, d=0.67) and VCO2 (753.1±125.5 vs 670.7±120.3 ml·min; P=0.036, d=0.67) during self-selected constant work-rate treadmill walking was also noted after training.ConclusionsOLT program used in this pilot study is feasible and improved both overground walking speed and walking economy in a small sample of people with chronic cervical iSCI. Future studies are necessary to establish the efficacy of this OLT program as well as to differentiate among potential mechanisms contributing to enhanced walking performance in people with iSCI following OLT.



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Age differences in physiological responses to self-paced and incremental $$\dot{V}{\text{O}}_{2\hbox{max} }$$ V ˙ O 2 max testing

Abstract

Purpose

A self-paced maximal exercise protocol has demonstrated higher \(\dot{V}{\text{O}}_{2\hbox{max} }\) values when compared against traditional tests. The aim was to compare physiological responses to this self-paced \(\dot{V}{\text{O}}_{2\hbox{max} }\) protocol (SPV) in comparison to a traditional ramp \(\dot{V}{\text{O}}_{2\hbox{max} }\) (RAMP) protocol in young (18–30 years) and old (50–75 years) participants.

Methods

Forty-four participants (22 young; 22 old) completed both protocols in a randomised, counter-balanced, crossover design. The SPV included 5 × 2 min stages, participants were able to self-regulate their power output (PO) by using incremental 'clamps' in ratings of perceived exertion. The RAMP consisted of either 15 or 20 W min−1.

Results

Expired gases, cardiac output (Q), stroke volume (SV), muscular deoxyhaemoglobin (deoxyHb) and electromyography (EMG) at the vastus lateralis were recorded throughout. Results demonstrated significantly higher \(\dot{V}{\text{O}}_{2\hbox{max} }\) in the SPV (49.68 ± 10.26 ml kg−1 min−1) vs. the RAMP (47.70 ± 9.98 ml kg−1 min−1) in the young, but not in the old group (>0.05). Q and SV were significantly higher in the SPV vs. the RAMP in the young (<0.05) but not in the old group (>0.05). No differences seen in deoxyHb and EMG for either age groups (>0.05). Peak PO was significantly higher in the SPV vs. the RAMP in both age groups (<0.05).

Conclusion

Findings demonstrate that the SPV produces higher \(\dot{V}{\text{O}}_{2\hbox{max} }\) , peak Q and SV values in the young group. However, older participants achieved similar \(\dot{V}{\text{O}}_{2\hbox{max} }\) values in both protocols, mostly likely due to age-related differences in cardiovascular responses to incremental exercise, despite them achieving a higher physiological workload in the SPV.



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Frequent Flyers: Messy ambulance problems

See all of Lenwood Brown's comics.



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Effect of Brain Computer Interface (BCI) in stress induced loss of cognition in hippocampus of wister albino rats

2016-12-11T03-54-58Z
Source: International Journal of Health and Rehabilitation Sciences (IJHRS)
Sivanandan Ramar, Mazen Alqahtani, Anandh Bose, Salameh Al Dajah.
Background: Brain-computer interface (BCI) is a collaboration between a brain and a device that enables signals from the brain to direct some external activity, which interface enables a direct communications pathway between the brain and the object to be controlled. By reading signals from an array of neurons and using computer chips and programs to translate the signals into action. The Magneto encephalography (MEG) is to record the firing of the neuron and absorb the brain activity as the magnetic field travels from region to region with in the brain. It has the potential to enhance the life style of the disabled person. The MEG Brain Computer Interface (BCI) impact on medicine and healthcare now may be subtle but is still revolutionary. Objectives: The purpose of this study was to develop novel methods and systems for rehabilitation and control of assistive devices using signals from the brain BCI on motor coding and on neural plasticity. Materials and methods: The experiment was carried out in 24 albino rats with Magneto encephalography (MEG). All the rats underwent BCI procedure except the first and second group which was exposed to fake intervention. The objective of this proof of concept closed loop BCI experiment was for the subject to control the positive movement of a rat in the radial arm maze to take the food even altered position which was recorded in the system. Results: An important finding in the present study was the enhancing effect of BCI against neurodegeneration. It shows that these rats achieve to learn the task. It suggests that the BCI activated the neurons in the hippocampus and makes it sufficient for normal acquisition. Conclusion: Stress induced hippocampal degeneration leads to significant impairment of cognitive functions especially in calculation, immediate recall and attention. In this present study, stress induced loss of cognition was studied by activating the neurons of the hippocampus by grid electrodes of BCI system. Keywords: Magneto encephalography (MEG), glucocorticoid, hippocampal formation & grid electrodes.


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