Identifying consistent biomechanical parameters across rising-to-walk subtasks to inform rehabilitation in practice: A systematic literature review

© 2020 Elsevier B.V. Background: :The best approach to rehabilitate the control of everyday whole-body movement (e.g. rise-to-walk) after pathology remains unclear in part because the associated controlled performance variables are not known. Rise-to-walk can be performed fluidly (sit-to-walk) or non-fluidly (sit-to-stand, proceeded by gait-initiation). Biomechanical variables that remain consistent in health regardless of how rise-to walk is performed represent controlled performance variable candidates which could monitor rehabilitative change. Research Question: :To determine if any biomechanical parameters remain consistent across rising-to-walk (RTW) subtasks (sit-to-stand, gait-initiation, and sit-to-walk) in healthy adults for purposes of movement control assessment in clinical practice. Methods: :Data sources included Medline, Cinahl, and Scopus databases, and the grey literature. Study selection was based on eligibility criteria and must have reported spatiotemporal, kinematic and/or kinetic biomechanical parameters featuring >1 RTW subtask. Data extraction and synthesis; standardised-mean-differences (SMDs) were calculated (pooled if replicated in >1 study) for each parameter. Consistency was determined if SMD95 %CIs included the zero-effect line. Results: :Nine studies (n = 99) were included (40 ± 7.5yrs). Seven parameters were replicated in >1 study and subjected to meta-analysis (fixed-effect model). Two were consistent between sit-to-stand and sit-to-walk: flexion-momentum time (M(95 %CI) = 0.055(-0.423 to 0.533); p = 0.823) and peak whole-body-centre-of-mass vertical velocity (M(95 %CI)= -0.415(-0.898 to 0.069); p = 0.093); and centre-of-pressure to whole-body-centre-of-mass distance at toe-off (M(95 %CI)= -0.137(-0.712 to 0.439); p = 0.642) between gait-initiation and sit-to-walk. Another 20 parameters were consistent based on single-study SMDs. Significance: :Consistent parameters might exist across RTW subtasks. However, the evidence is based on few studies with small samples and variable RTW protocols. Future studies designed to confirm consistency using a standardised RTW protocol are needed

Type 2 diabetes: a cohort study of treatment, ethnic and social group influences on glycated haemoglobin

OBJECTIVES: To assess whether in people with poorly controlled type 2 diabetes (HbA1c>7.5%) improvement in HbA1c varies by ethnic and social group. DESIGN: Prospective 2-year cohort of type 2 diabetes treated in general practice. SETTING AND PARTICIPANTS: All patients with type 2 diabetes in 100 of the 101 general practices in two London boroughs. The sample consisted of an ethnically diverse group with uncontrolled type 2 diabetes aged 37–71 years in 2007 and with HbA1c recording in 2008–2009. OUTCOME MEASURE: Change from baseline HbA1c in 2007 and achievement of HbA1c control in 2008 and 2009 were estimated for each ethnic, social and treatment group using multilevel modelling. RESULTS: The sample consisted of 6104 people; 18% were white, 63% south Asian, 16% black African/Caribbean and 3% other ethnic groups. HbA1c was lower after 1 and 2 years in all ethnic groups but south Asian people received significantly less benefit from each diabetes treatment. After adjustment, south Asian people were found to have 0.14% less reduction in HbA1c compared to white people (95% CI 0.04% to 0.24%) and white people were 1.6 (95% CI 1.2 to 2.0) times more likely to achieve HbA1c controlled to 7.5% or less relative to south Asian people. HbA1c reduction and control in black African/Caribbean and white people did not differ significantly. There was no evidence that social deprivation influenced HbA1c reduction or control in this cohort. CONCLUSIONS: In all treatment groups, south Asian people with poorly controlled diabetes are less likely to achieve controlled HbA1c, with less reduction in mean HbA1c than white or black African/Caribbean people

Parameters that remain consistent independent of pausing before gait-initiation during normal rise-to-walk behaviour delineated by sit-to-walk and sit-to-stand-and-walk.

BACKGROUND: Rising-to-walk is an everyday transitional movement task rarely employed in gait rehabilitation. Sit-to-walk (STW) and sit-to-stand-and-walk (STSW), where a pause separates sit-to-stand and gait-initiation (GI) represent extremes of rising-to-walk behaviour. Delayed GI can indicate pathological impairment but is also observed in healthy individuals. We hypothesise that healthy subjects express consistent biomechanical parameters, among others that differ, during successful rising-to-walk task performance regardless of behaviour. This study therefore sought to identify if any parameters are consistent between STW and STSW in health because they represent normal rise-to-walk performance independent of pause, and also because they represent candidate parameters sensitive enough to monitor change in pathology. METHODS: Ten healthy volunteers performed 5 trials of STW and STSW. Event timing, ground-reaction-forces (GRFs), whole-body-centre-of-mass (BCoM) displacement, and centre-of-pressure (CoP) to extrapolated BCoM (xCoM) distance (indicator of positional stability) up to the 3rd step were compared between-tasks with paired t-tests. For consistent parameters; agreement between-tasks was assessed using Bland-Altman analyses and minimal-detectable-change (MDC) calculations. RESULTS: Mean vertical GRFs, peak forward momentum and fluidity during rising; CoP-xCoM separation at seat-off, upright, GI-onset, and steps1-2; and forward BCoM velocity were all significantly greater in STW. In contrast, peak BCoM vertical momentum, flexion-momentum time, and 3rd step stability were consistent between tasks and yielded acceptable reliability. CONCLUSION: STW is a more challenging task due to the merging of rising with GI reflected by greater CoP-xCoM separation compared to STSW indicative of more positional instability. However, BCoM vertical momentum, flexion-momentum time, and step3 stability remained consistent in healthy individuals and are therefore candidates with which to monitor change in gait rehabilitation following pathology. Future studies should impose typical pause-durations observed in pathology upon healthy subjects to determine if the parameters we have identified remain consistent

Sit-to-stand-and-walk from 120% knee height: A novel approach to assess dynamic postural control independent of lead-limb

© 2016 Journal of Visualized Experiments.Individuals with sensorimotor pathology e.g., stroke have difficulty executing the common task of rising from sitting and initiating gait (sit-to-walk: STW). Thus, in clinical rehabilitation separation of sit-to-stand and gait initiation - termed sit-to-stand-and-walk (STSW) - is usual. However, a standardized STSW protocol with a clearly defined analytical approach suitable for pathological assessment has yet to be defined. Hence, a goal-orientated protocol is defined that is suitable for healthy and compromised individuals by requiring the rising phase to be initiated from 120% knee height with a wide base of support independent of lead limb. Optical capture of three-dimensional (3D) segmental movement trajectories, and force platforms to yield two-dimensional (2D) center-of-pressure (COP) trajectories permit tracking of the horizontal distance between COP and whole-body-center-of-mass (BCOM), the decrease of which increases positional stability but is proposed to represent poor dynamic postural control. BCOM-COP distance is expressed with and without normalization to subjects' leg length. Whilst COP-BCOM distances vary through STSW, normalized data at the key movement events of seat-off and initial toe-off (TO1) during steps 1 and 2 have low intra and inter subject variability in 5 repeated trials performed by 10 young healthy individuals. Thus, comparing COP-BCOM distance at key events during performance of an STSW paradigm between patients with upper motor neuron injury, or other compromised patient groups, and normative data in young healthy individuals is a novel methodology for evaluation of dynamic postural stability

Chromatin structure and evolution in the human genome

<p>Abstract</p> <p>Background</p> <p>Evolutionary rates are not constant across the human genome but genes in close proximity have been shown to experience similar levels of divergence and selection. The higher-order organisation of chromosomes has often been invoked to explain such phenomena but previously there has been insufficient data on chromosome structure to investigate this rigorously. Using the results of a recent genome-wide analysis of open and closed human chromatin structures we have investigated the global association between divergence, selection and chromatin structure for the first time.</p> <p>Results</p> <p>In this study we have shown that, paradoxically, synonymous site divergence (dS) at non-CpG sites is highest in regions of open chromatin, primarily as a result of an increased number of transitions, while the rates of other traditional measures of mutation (intergenic, intronic and ancient repeat divergence as well as SNP density) are highest in closed regions of the genome. Analysis of human-chimpanzee divergence across intron-exon boundaries indicates that although genes in relatively open chromatin generally display little selection at their synonymous sites, those in closed regions show markedly lower divergence at their fourfold degenerate sites than in neighbouring introns and intergenic regions. Exclusion of known Exonic Splice Enhancer hexamers has little affect on the divergence observed at fourfold degenerate sites across chromatin categories; however, we show that closed chromatin is enriched with certain classes of ncRNA genes whose RNA secondary structure may be particularly important.</p> <p>Conclusion</p> <p>We conclude that, overall, non-CpG mutation rates are lowest in open regions of the genome and that regions of the genome with a closed chromatin structure have the highest background mutation rate. This might reflect lower rates of DNA damage or enhanced DNA repair processes in regions of open chromatin. Our results also indicate that dS is a poor measure of mutation rates, particularly when used in closed regions of the genome, as genes in closed regions generally display relatively strong levels of selection at their synonymous sites.</p

Sit-to-walk and sit-to-stand-and-walk task dynamics are maintained during rising at an elevated seat-height independent of lead-limb in healthy individuals

© 2016 Elsevier B.V.Introduction: Sit-to-walk (STW) is a common transitional motor task not usually included in rehabilitation. Typically, sit-to-stand (STS), pause, then gait initiation (GI) before walking is used, which we term sit-to-stand-and-walk (STSW). Separation between centre-of-pressure (COP) and whole-body centre-of-mass (BCOM) during GI is associated with dynamic postural stability. Rising from seats higher than knee-height (KH) is more achievable for patients, but whether this and/or lead-limb significantly affects task dynamics is unclear. This study tested whether rising from seat-heights and lead-limb affects STW and STSW task dynamics in young healthy individuals. Methods: Ten (5F) young (29 ± 7.7 years) participants performed STW and STSW from a standardised position. Five trials of each task were completed at 100 and 120%KH leading with dominant and non-dominant legs. Four force-plates and optical motion capture delineated key movement events and phases with effect of seat-height and lead-limb determined by 2-way ANOVA within tasks. Results: At 120%KH, lower peak vertical ground-reaction-forces (vGRFs) and vertical BCOM velocities were observed during rising irrespective of lead-limb. No other parameters differed between seat-heights or lead-limbs. During GI in STSW there was more lateral, and less posterior, COP excursion than expected. Conclusion: Reduction in vGRFs and velocity during rising at 120%KH is consistent with reduced effort in young healthy individuals and is likely therefore to be an appropriate seat-height for patients. Lead-limb had no effect upon STSW or STW parameters suggesting that normative data independent of lead-limb can be utilised to monitor motor rehabilitation should differences be observed in patients. STSW should be considered an independent movement transition

Sequencing and analysis of an Irish human genome

BACKGROUND: Recent studies generating complete human sequences from Asian, African and European subgroups have revealed population-specific variation and disease susceptibility loci. Here, choosing a DNA sample from a population of interest due to its relative geographical isolation and genetic impact on further populations, we extend the above studies through the generation of 11-fold coverage of the first Irish human genome sequence. RESULTS: Using sequence data from a branch of the European ancestral tree as yet unsequenced, we identify variants that may be specific to this population. Through comparisons with HapMap and previous genetic association studies, we identified novel disease-associated variants, including a novel nonsense variant putatively associated with inflammatory bowel disease. We describe a novel method for improving SNP calling accuracy at low genome coverage using haplotype information. This analysis has implications for future re-sequencing studies and validates the imputation of Irish haplotypes using data from the current Human Genome Diversity Cell Line Panel (HGDP-CEPH). Finally, we identify gene duplication events as constituting significant targets of recent positive selection in the human lineage. CONCLUSIONS: Our findings show that there remains utility in generating whole genome sequences to illustrate both general principles and reveal specific instances of human biology. With increasing access to low cost sequencing we would predict that even armed with the resources of a small research group a number of similar initiatives geared towards answering specific biological questions will emerge

AIDS-Related Mycoses: Current Progress in the Field and Future Priorities.

Opportunistic fungal infections continue to take an unacceptably heavy toll on the most disadvantaged living with HIV-AIDS, and are a major driver for HIV-related deaths. At the second EMBO Workshop on AIDS-Related Mycoses, clinicians and scientists from around the world reported current progress and key priorities for improving outcomes from HIV-related mycoses

The secret world of shrimps: polarisation vision at its best

Animal vision spans a great range of complexity, with systems evolving to detect variations in optical intensity, distribution, colour, and polarisation. Polarisation vision systems studied to date detect one to four channels of linear polarisation, combining them in opponent pairs to provide intensity-independent operation. Circular polarisation vision has never been seen, and is widely believed to play no part in animal vision. Polarisation is fully measured via Stokes' parameters--obtained by combined linear and circular polarisation measurements. Optimal polarisation vision is the ability to see Stokes' parameters: here we show that the crustacean \emph{Gonodactylus smithii} measures the exact components required. This vision provides optimal contrast-enhancement, and precise determination of polarisation with no confusion-states or neutral-points--significant advantages. We emphasise that linear and circular polarisation vision are not different modalities--both are necessary for optimal polarisation vision, regardless of the presence of strongly linear or circularly polarised features in the animal's environment.Comment: 10 pages, 6 figures, 2 table