2,177 research outputs found
The between-day reliability of peroneus longus EMG during walking
The peroneus longus (PL) is a rearfoot evertor, important in frontal plane foot motion. Studying PL function has been limited by previous electromyography (EMG) studies reporting poor between-day reliability. Due to its close proximity to adjacent muscles, EMG measures of PL may be susceptible to crosstalk, thus correct electrode placement is vital. The aim of this study was to use ultrasound to aid placement of small surface EMG electrodes and determine the between-day reliability of PL EMG in healthy participants' walking. Ten participants walked barefoot and shod at a controlled, self-selected speed. Six trials per condition, per session, were recorded over two days (mean (SD): 5 (3) days apart). The muscle belly was located using ultrasound. EMG was recorded with surface electrodes (Trigno Mini, Delsys, Inc.) at 2000 Hz. Amplitude was normalized to the peak per gait cycle and time normalized to the gait cycle. Reliability of discrete variables were primarily assessed with the standard error of measurement (SEM), plus the coefficient of multiple correlation (CMC), the coefficient of variation (CV) and the intra-class correlation coefficient (ICC). The pattern of the EMG profile was consistent. The SEM of peak amplitude was 4% (3-8%) and 3% (2-5%) for barefoot and shod respectively. For timing of the peak the SEM was 2% (1-3%) and 1% (1-2%) for barefoot and shod respectively. Low SEM of discrete variables suggests good reliability of PL EMG during walking supporting the future use of this protocol. Therefore activation of PL can be confidently studied in repeated-measures study designs
A systematic review of the effect of footwear, foot orthoses and taping on lower limb muscle activity during walking and running
Background:
External devices are used to manage musculoskeletal pathologies by altering loading of the foot, which could result in altered muscle activity that could have therapeutic benefits.
Objectives:
To establish if evidence exists that footwear, foot orthoses and taping alter lower limb muscle activity during walking and running.
Study design:
Systematic literature review.
Methods:
CINAHL, MEDLINE, ScienceDirect, SPORTDiscus and Web of Science databases were searched. Quality assessment was performed using guidelines for assessing healthcare interventions and electromyography methodology.
Results:
Thirty-one studies were included: 22 related to footwear, eight foot orthoses and one taping. In walking, (1) rocker footwear apparently decreases tibialis anterior activity and increases triceps surae activity, (2) orthoses could decrease activity of tibialis posterior and increase activity of peroneus longus and (3) other footwear and taping effects are unclear.
Conclusion:
Modifications in shoe or orthosis design in the sagittal or frontal plane can alter activation in walking of muscles acting primarily in these planes. Adequately powered research with kinematic and kinetic data is needed to explain the presence/absence of changes in muscle activation with external devices.
Clinical relevance:
This review provides some evidence that foot orthoses can reduce tibialis posterior activity, potentially benefitting specific musculoskeletal pathologies
Genetic Testing Before Anticoagulation? A Systematic Review of Pharmacogenetic Dosing of Warfarin
Genotype-guided initial warfarin dosing may reduce over-anticoagulation and serious bleeding compared to a one-dose-fits-all dosing method.
The objective of this review was to investigate the safety and efficacy of genotype-guided dosing of warfarin in reducing the occurrence of serious bleeding events and over-anticoagulation.
The authors searched PubMed, EMBASE and International Pharmaceutical Abstracts through January 23, 2009, without language restrictions. Selected articles were randomized trials comparing pharmacogenetic dosing of warfarin versus a “standard” dose control algorithm in adult patients taking warfarin for the first time.
Two reviewers independently extracted data and assessed study quality using a validated instrument. The primary outcomes were major bleeding and time spent within the therapeutic range International Normalized Ratio (INR). Secondary outcomes included minor bleeding, thrombotic events and other measures of anticoagulation quality.
Three of 2,014 studies (423 patients) met the inclusion and exclusion criteria. Differences in study quality, dosing algorithms, length of follow-up and outcome measures limited meta-analysis. Summary estimates revealed no statistically significant difference in bleeding rates or time within the therapeutic range INR. The highest quality study found no significant difference in primary or secondary outcomes, although there was a trend towards more rapid achievement of a stable dose (14.1 vs. 19.6 days, p = 0.07) in the pharmocogenetic arm.
We did not find sufficient evidence to support the use of pharmacogenetics to guide warfarin therapy. Additional clinical trials are needed to define the optimal approach to use warfarin pharmacogenetics in clinical practice
Tracking Data Relay Satellite System (TDRSS) VHF propagation study
A study performed to investigate the use of the Bent Ionospheric Model in computing corrections to the range and range rate measurements of the TDRSS satellites is documented. Several orbital configurations between the two satellites are discussed as to their effects on total electron content along the radio path between the satellites. Problem areas in the accurate computation of total electron content and range rate corrections are also discussed. The Bent Ionospheric Model gives the electron density versus height profile as a function of latitude, longitude, height, time, season, and solar flux
Location-specific cutaneous electrical stimulation of the footsole modulates corticospinal excitability to the plantarflexors and dorsiflexors during standing
Non-noxious electrical stimulation to distinct locations of the foot sole evokes location-specific cutaneous reflex responses in lower limb muscles. These reflexes occur at latencies that may enable them to be mediated via a transcortical pathway. Corticospinal excitability to the plantarflexors and dorsiflexors was measured in 16 participants using motor evoked potentials (MEPs). Spinal excitability was measured in eight of the original participants using cervicomedullary motor evoked potentials (CMEPs). Measurements were collected with and without preceding cutaneous stimulus to either the heel (HEEL) or metatarsal (MET) locations of the foot sole, and evoked potentials were elicited to coincide with the arrival of the cutaneous volley at either the motor cortex or spinal cord. Plantarflexor MEPs and CMEPs were facilitated with cutaneous stimulation to the HEEL for MEPs (soleus p = 0.04, medial gastrocnemius (MG) p = 0.017) and CMEPs (soleus p = 0.047 and MG p = 0.015), but they were unchanged following MET stimulation for MEPs or CMEPs. Dorsiflexor MEPs were unchanged with cutaneous stimulation at either location, but dorsiflexor CMEPs increased with cutaneous stimulation (p = 0.05). In general, the increase in CMEP amplitudes was larger than the increase in MEP amplitudes, indicating that an increase in spinal excitability likely explains most of the increase in corticospinal excitability. The larger change observed in the CMEP also indicates that excitability from supraspinal sources likely decreased, which could be due to a net change in the excitability of intracortical circuits. This study provides evidence that cutaneous reflexes from foot sole skin are likely influenced by a transcortical pathway
Can differences in phosphorus uptake kinetics explain the distribution of cattail and sawgrass in the Florida Everglades?
<p>Abstract</p> <p>Background</p> <p>Cattail (<it>Typha domingensis</it>) has been spreading in phosphorus (P) enriched areas of the oligotrophic Florida Everglades at the expense of sawgrass (<it>Cladium mariscus </it>spp. <it>jamaicense</it>). Abundant evidence in the literature explains how the opportunistic features of <it>Typha </it>might lead to a complete dominance in P-enriched areas. Less clear is how <it>Typha </it>can grow and acquire P at extremely low P levels, which prevail in the unimpacted areas of the Everglades.</p> <p>Results</p> <p>Apparent P uptake kinetics were measured for intact plants of <it>Cladium </it>and <it>Typha </it>acclimated to low and high P at two levels of oxygen in hydroponic culture. The saturated rate of P uptake was higher in <it>Typha </it>than in <it>Cladium </it>and higher in low-P acclimated plants than in high-P acclimated plants. The affinity for P uptake was two-fold higher in <it>Typha </it>than in <it>Cladium</it>, and two- to three-fold higher for low-P acclimated plants compared to high-P acclimated plants. As <it>Cladium </it>had a greater proportion of its biomass allocated to roots, the overall uptake capacity of the two species at high P did not differ. At low P availability, <it>Typha </it>increased biomass allocation to roots more than <it>Cladium</it>. Both species also adjusted their P uptake kinetics, but <it>Typha </it>more so than <it>Cladium</it>. The adjustment of the P uptake system and increased biomass allocation to roots resulted in a five-fold higher uptake per plant for <it>Cladium </it>and a ten-fold higher uptake for <it>Typha</it>.</p> <p>Conclusions</p> <p>Both <it>Cladium </it>and <it>Typha </it>adjust P uptake kinetics in relation to plant demand when P availability is high. When P concentrations are low, however, <it>Typha </it>adjusts P uptake kinetics and also increases allocation to roots more so than <it>Cladium</it>, thereby improving both efficiency and capacity of P uptake. <it>Cladium </it>has less need to adjust P uptake kinetics because it is already efficient at acquiring P from peat soils (e.g., through secretion of phosphatases, symbiosis with arbuscular mycorrhizal fungi, nutrient conservation growth traits). Thus, although <it>Cladium </it>and <it>Typha </it>have qualitatively similar strategies to improve P-uptake efficiency and capacity under low P-conditions, <it>Typha </it>shows a quantitatively greater response, possibly due to a lesser expression of these mechanisms than <it>Cladium</it>. This difference between the two species helps to explain why an opportunistic species such as <it>Typha </it>is able to grow side by side with <it>Cladium </it>in the P-deficient Everglades.</p
Exocyst mutants suppress pollen tube growth and cell wall structural defects of hydroxyproline O‐arabinosyltransferase mutants
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156472/1/tpj14808-sup-0003-FigS3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156472/9/tpj14808.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156472/8/tpj14808-sup-0001-FigS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156472/7/tpj14808-sup-0004-FigS4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156472/6/tpj14808-sup-0005-FigS5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156472/5/tpj14808-sup-0007-FigS7.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156472/4/tpj14808-sup-0006-FigS6.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156472/3/tpj14808-sup-0002-FigS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156472/2/tpj14808_am.pd
Bacteriological and serological characterisation of slaughter pigs from 25 serologically identified salmonella high risk herds
Danish finishing herds are routinely screened for antibodies to Salmonella in random samples of meat juice from slaughter pigs. The herds are categorized by the seroprevalence of samples from the preceding three months into three infection levels (1, 2 and 3). Herds are allocated to level 3 ( Salmonella high risk herds) at seroprevalences exceeding 33-50% depending on herd size (larger herds lower limit) (Mousing et al., in press)
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