Modified conventional gait model vs. Six degrees of freedom model: A comparison of lower limb kinematics and associated error.

BACKGROUND: The conventional gait model (CGM) is commonly utilised within clinical motion analysis but has a number of inherent limitations. To overcome some of these limitations modifications have been made to the CGM and six-degrees of freedom models (6DoF) have been developed. RESEARCH QUESTION: How comparable are lower limb kinematics calculated using modified CGM and 6DoF models and what is the error associated with the output of each model during walking? METHODS: Ten healthy males attended two gait analysis sessions, in which they walked at a self-selected pace, while a 10-camera motion capture system recorded lower limb kinematics. Hip, knee and ankle joint kinematics in all three anatomical planes were calculated using a modified CGM, with medial anatomical markers and a three-dimensional foot added, and 6DoF. Mean absolute differences were calculated on a point-by-point basis over the walking gait cycle and interpreted relative to a 5° threshold to explore the comparability of model outputs. The standard error of the measurement (SEM) was also calculated on a point-by-point basis over the walking gait cycle for each model. RESULTS: Mean absolute differences above 5° were reported between the two model outputs in 58-86% of the walking gait cycle at the knee in the frontal plane, and over the entire walking gait cycle at the hip and knee in the transverse plane. SEM was typically larger for the modified CGM compared to the 6DoF, with the highest SEM values reported at the knee in the frontal plane, and the hip and the knee in the transverse plane. SIGNIFICANCE: Caution should be taken when looking to compare findings between studies utilising modified CGM and 6DoF outside of the sagittal plane, especially at the hip and knee. The reduced SEM associated with the 6DoF suggests this modelling approach may be preferable.

Reduced vitamin D levels in painful diabetic peripheral neuropathy.

AIM: Recent studies have reported an association between low vitamin D levels and diabetic peripheral neuropathy. However, many of these did not differentiate between people with painful diabetic peripheral neuropathy and those with painless diabetic peripheral neuropathy, or assess major confounding factors including sunlight exposure and daily activity. Our study addressed these limitations and evaluated vitamin D levels in people with carefully phenotyped diabetic peripheral neuropathy and controls. METHODS: Forty-five white Europeans with Type 2 diabetes and 14 healthy volunteers underwent clinical and neurophysiological assessments. People with Type 2 diabetes were then divided into three groups (17 with painful diabetic peripheral neuropathy, 14 with painless diabetic peripheral neuropathy and 14 with no diabetic peripheral neuropathy). All had seasonal sunlight exposure and daily activity measured, underwent a lower limb skin biopsy and had 25-hydroxyvitamin D measured during the summer months, July to September. RESULTS: After adjusting for age, BMI, activity score and sunlight exposure, 25-hydroxyvitamin D levels (nmol/l) (se) were significantly lower in people with painful diabetic peripheral neuropathy [painful diabetic peripheral neuropathy 34.9 (5.8), healthy volunteers 62.05 (6.7), no diabetic peripheral neuropathy 49.6 (6.1), painless diabetic peripheral neuropathy 53.1 (6.2); ANCOVAP = 0.03]. Direct logistic regression was used to assess the impact of seven independent variables on painful diabetic peripheral neuropathy. Vitamin D was the only independent variable to make a statistically significant contribution to the model with an inverted odds ratio of 1.11. Lower 25-hydroxyvitamin D levels also correlated with lower cold detection thresholds (r = 0.39, P = 0.02) and subepidermal nerve fibre densities (r = 0.42, P = 0.01). CONCLUSIONS: We have demonstrated a significant difference in 25-hydroxyvitamin D levels in well-characterized people with painful diabetic peripheral neuropathy, while accounting for the main confounding factors. This suggests a possible role for vitamin D in the pathogenesis of painful diabetic peripheral neuropathy. Further prospective and intervention trials are required to prove causality between low vitamin D levels and painful diabetic peripheral neuropathy.

The Use of Silgel STC-SE, a Topical Silicone Gel for the Treatment and Reduction of Hypertrophic and Keloid Scars.

BACKGROUND: A single-center study assessing the efficacy of Nagor's Silgel STC-SE silicone gel to reduce the appearance of hypertrophic and keloid scars. METHODS: A 16-week controlled study of 36 patients with hypertrophic or keloid scars. The subjects were divided between 2 cohorts: one assessing recently healed scars (<6 mo) and other assessing older scars (6 mo to 2 y). The efficacy of Silgel STC-SE on the scar was evaluated by skin hydration, skin moisture evaporation, skin elasticity, basic scar measurements, subjective patient questionnaire data, and image analysis. All subjects had data collected at baseline and weeks 1, 4, 8, 12, and 16. Photographs were taken for image analysis at baseline, week 8, and week 16. Statistical analysis was conducted on all data. RESULTS: Twenty-nine patients completed the study (27 presented with hypertrophic scars and 2 with keloid scars), and 90% reported a marked improvement in their scar appearance. Patient questionnaire data showed great satisfaction with the product. Image analysis showed visual improvement with a statistically significant reduction of the "red" color of scars. Overall, scar dimensions were significantly reduced. There was a significant decrease from baseline levels in average scar length. Skin elasticity, skin hydration, and skin moisture evaporation did not change significantly from baseline. CONCLUSIONS: The results of this study indicate that Silgel STC-SE is an effective treatment in reducing the appearance and red color of hypertrophic scars up to 2 years old. Further study is required to draw significant conclusion in regard to the treatment of keloid scars.

A hierarchical model of factors influencing a battery of agility tests.

AIM: The aim of this study was to investigate the hierarchical contributions of anthropometry, strength and cognition to a battery of prescriptive and reactive agility tests. METHODS: Nineteen participants (mean±S.D.; age:22.1±1.9 years; height: 182.9±5.5 cm; body mass: 77±4.9 kg) completed four agility tests: a prescriptive linear sprint, a prescriptive change-of-direction sprint, a reactive change-of-direction sprint, and a reactive linear deceleration test. Anthropometric variables included body fat percentage and thigh girth. Strength was quantified as the peak eccentric hamstring torque at 180, 300, and 60°·s-1. Mean reaction time and accuracy in the Stroop word-colour Test was used to assess perceptual and decision making factors. RESULTS: There was little evidence of intertest correlation with the strongest relationship observed between 10 m sprint and t-test performance (r2=0.49, P<0.01). Anthropometric measures were not strong predictors of agility, accounting for a maximum 23% (P=0.12) in the prescriptive change-of-direction test. Cognitive measures had a stronger correlation with the reactive (rather than prescriptive) agility tests, with a maximum 33% (P=0.04) of variance accounted for in the reactive change-of-direction test. Eccentric hamstring strength accounted for 62% (P=0.01) of the variance in the prescriptive change-of-direction test. Hierarchical ordering of the agility tests revealed that eccentric hamstring strength was the primary predictor in 3 of the 4 tests, with cognitive accuracy the next most common predictor. CONCLUSION: There is little evidence of inter-test correlation across a battery of agility tests. Eccentric hamstring strength and decision making accuracy are the most common predictors of agility performance.

An ergonomics action research demonstration: integrating human factors into assembly design processes.

In action research (AR), the researcher participates 'in' the actions in an organisation, while simultaneously reflecting 'on' the actions to promote learning for both the organisation and the researchers. This paper demonstrates a longitudinal AR collaboration with an electronics manufacturing firm where the goal was to improve the organisation's ability to integrate human factors (HF) proactively into their design processes. During the three-year collaboration, all meetings, workshops, interviews and reflections were digitally recorded and qualitatively analysed to inform new 'actions'. By the end of the collaboration, HF tools with targets and sign-off by the HF specialist were integrated into several stages of the design process, and engineers were held accountable for meeting the HF targets. We conclude that the AR approach combined with targeting multiple initiatives at different stages of the design process helped the organisation find ways to integrate HF into their processes in a sustainable way. PRACTITIONER SUMMARY: Researchers acted as a catalyst to help integrate HF into the engineering design process in a sustainable way. This paper demonstrates how an AR approach can help achieve HF integration, the benefits of using a reflective stance and one method for reporting an AR study.

The effects of multidirectional soccer-specific fatigue on markers of hamstring injury risk.

The purpose of this work was to investigate the effect of multidirectional soccer-specific fatigue on hamstring muscle strength and angle of peak torque. Sixteen male semi-professional soccer players (mean+/-S.D.: age: 21.3+/-2.9 years; height 185.0+/-8.7 cm; body mass 81.6+/-6.7 kg) completed the SAFT(90), a multidirectional, intermittent 90-min exercise protocol based on data from English Championship soccer matches. Prior to exercise (t(0)), at half-time (t(45)) and post-exercise (t(105)), subjects performed three maximal dominant limb isokinetic contractions (Biodex, System 3) at 120 degrees s(-1) through a 90 degrees range for concentric and eccentric knee flexors and concentric knee extensors. Analysis of variance revealed significant time dependant reductions in gravity corrected eccentric hamstring peak torque, and consequently in the functional hamstring:quadriceps ratio (P<0.01). Eccentric hamstring peak torque decreased significantly during each half (t(0): 272.0+/-43.2; t(45): 240.4+/-43.3; t(105): 226.3+/-45.7 Nm). The functional hamstring:quadriceps ratio also decreased significantly during each half (t(0): 116.6+/-21.2; t(45): 107.1+/-17.6; t(105): 98.8+/-20.3%). There were no significant changes in concentric hamstring or quadriceps peak torque observed during SAFT(90) (P>0.05). Data analysis also revealed significant differences for Angle of Peak Torque for eccentric hamstrings (P<0.05) which was significantly higher at the end of each half (t(45): 37+/-15; t(105): 38+/-18 degrees ) than the pre-exercise value (t(0): 28+/-12 degrees ). There was a time dependant decrease in peak eccentric hamstring torque and in the functional strength ratio which may have implications for the increased predisposition to hamstring strain injury during the latter stages of match-play.

Association of white matter hyperintensity measurements on brain MR imaging with cognitive status, medial temporal atrophy, and cardiovascular risk factors.

BACKGROUND AND PURPOSE: White matter hyperintensities (WMHs) are frequently characterized as markers of cerebrovascular disease, whereas medial temporal atrophy (MTA) is a recognized marker of Alzheimer disease (AD). Our purpose was to test the reliability of a visual rating system (VRS) in evaluating WMHs and MTA and in distinguishing healthy from cognitively impaired subjects. MATERIALS AND METHODS: Subjects (n = 192) enrolled in the Florida Alzheimer's Disease Research Center were diagnosed with no cognitive impairment, nonamnestic mild cognitive impairment (na-MCI), amnestic MCI (a-MCI), or probable AD. The severity of WMHs was assessed on T2-weighted fluid-attenuated inversion recovery axial MR images, and the severity of MTA was evaluated on 1.5-mm-thick coronal MR images by using a computer-based visual rating system. Cardiovascular risk factor scores were calculated as the sum of 10 independent cardiovascular risk factors. RESULTS: WMH and MTA scores were greater in subjects with probable AD, relative to those with no cognitive impairment and na-MCI. MTA scores differentiated subjects with a-MCI from those with no cognitive impairment and na-MCI. The total WMH score was significantly related to MTA (r = 0.39; P < .001) but not to cardiovascular risk factor scores (r = 0.07; P = not significant). The overall correct classification rate of probable AD versus no cognitive impairment by using MTA scores was 81.8%, improving to 86.5% when combined with WMH scores. CONCLUSIONS: Both MTA and WMH scores distinguished subjects with no cognitive impairment and probable AD. Combining MTA and WMH scores improved the correct classification rate, whereas WMH scores were significantly related to MTA scores, but not to cardiovascular risk factor scores. This finding suggests that among subjects with a-MCI and probable AD, WMHs on MR images are primarily associated with neurodegenerative disease.

Soccer fatigue, sprinting and hamstring injury risk.

The aim of this study was to investigate the effect of a multi-directional soccer-specific fatigue protocol on sprinting kinematics in relation to hamstring injury risk. Nine semi-professional soccer players (Mean +/- SD: Age: 21.3 +/- 2.9 year; Height 185.0 +/- 8.7 cm; Body Mass 81.6 +/- 6.7 kg) completed the SAFT(90); a multi-directional, intermittent 90 min exercise protocol representative of soccer match-play. The 10m sprint times and three-dimensional kinematic data were recorded using a high-speed motion capture system (Qualisys Track Manager) every 15 min during the SAFT(90). A significant time dependent increase was observed in sprint time during the SAFT(90) (P<0.01) with a corresponding significant decrease in stride length (P<0.01). Analysis of the kinematic sprint data revealed significantly reduced combined maximal hip flexion and knee extension angle, indicating reduced hamstring length, between pre-exercise and half-time (P<0.01) and pre-exercise and full-time (P<0.05). These findings revealed that the SAFT(90) produced time dependent impairments in sprinting performance and kinematics of technique which may result from shorter hamstring muscle length. Alterations in sprinting technique may have implications for the increased predisposition to hamstring strain injury during the latter stages of soccer match-play.

Medial temporal lobe atrophy on MRI scans and the diagnosis of Alzheimer disease.

BACKGROUND: Despite convenience, accessibility, and strong correlation to severity of Alzheimer disease (AD) pathology, medial temporal lobe atrophy (MTA) has not been used as a criterion in the diagnosis of prodromal and probable AD. METHODS: Using a newly validated visual rating system, mean MTA scores of three bilateral medial temporal lobe structures were compared for subjects with no cognitive impairment (NCI) (n = 117), nonamnestic mild cognitive impairment (MCI) (n = 46), amnestic MCI (n = 45), and probable AD (n = 53). Correlations between MTA scores and neuropsychological test scores at baseline, and predictors of change in diagnosis at 1-year follow-up were evaluated. RESULTS: With NCI as the reference group, a mean MTA cut score of 1.33 yielded an optimal sensitivity/specificity of 85%/82% for probable AD subjects and 80%/82% for amnestic MCI subjects. MTA and Clinical Dementia Rating Sum of Boxes scores at baseline were independent and additive predictors of diagnosis at baseline, and of transition from NCI to MCI or from MCI to dementia at 1-year follow-up. CONCLUSION: Medial temporal lobe atrophy (MTA) scores 1) distinguish probable Alzheimer disease (AD) and amnestic mild cognitive impairment (MCI) subjects from nonamnestic MCI and no cognitive impairment (NCI) subjects, 2) help predict diagnosis at baseline, and 3) predict transition from NCI to MCI and from MCI to probable AD. MTA scores should be used as a criterion in the clinical diagnosis of AD.

Suprascapular nerve block as a method of preemptive pain control in shoulder surgery.

The purpose of the study was to evaluate the effect of suprascapular nerve block (SSNB) in shoulder surgery. The study group consisted of 260 patients, which were subjected to shoulder operations. The patients were divided into two equal groups: group I with nerve block compared to a control group II without a nerve block. The mean age of the patients in group I was 56.2 +/- 6.86 years and that in group II was 54.5 +/- 7.06 years. The female to male ratio was 71:59 in group I and was 69:61 in group II. Surgical procedures were arthroscopic rotator cuff repair, arthroscopic subacromial decompression, arthroscopic acromioclavicular resection, arthroscopic removal of calcific tendonitis, arthroscopic reconstruction of instability, arthroscopic capsular release and shoulder replacement. In all cases the pain was documented by the visual analogue scale (VAS) preoperative, at the first, the second as well as at the third day after surgery. In order to evaluate the amount of fluid, which is needed for infiltration of the area of the supraspinatus fossa, we injected different amount of local anesthetic in combination with contrast dye in five patients. In this study to document the fluid distribution, after injecting with different milliliters, 10 ml is proved to be more than enough to have sufficient local anesthetic to block the SSN. Pre-operatively the mean VAS was comparable between both groups. We documented a significant difference in favour of SSNB from day 1 to day 3 after surgery. No specific complications due to this nerve block procedure were found in any patient post-operatively.

Soccer half-time strategy influences thermoregulation and endurance performance.

AIM: In the first 15 min of the second half in professional soccer, there is a reduction of high intensity distance covered and a high incidence of injuries sustained, possibly due to a reduction in body temperature during the half-time (HT). The aim of this study was to investigate the effect of active and passive re-warm-up strategies on cardiovascular (heart rate, HR) and thermoregulatory stress, and second-half soccer-specific endurance performance (SSEP). METHODS: Seven professional players performed two intermittent field tests of 16.5 min duration, with a 15 min HT. On separate, randomised occasions, 4 trials were completed during which different HT strategies were undertaken between minutes 7 and 14 of the HT interval. Two passive trials were completed: rest control trial (CON), or players were immersed to the gluteal fold in a hot bath (approximately 40 degrees C-passive heating, PH); in the active trials, players performed at 70% maximum HR, either steady-state non-specific active heating (cycling, NSAH) or intermittent soccer-specific active heating (sprinting repeatedly, SSAH). HR and core temperature (Tc) were measured every 5 min, and body weight was recorded pre and post each trial. RESULTS: Active re-warm-up strategies maintained SSEP in the second period with respect to CON (P<0.01), whereas PH did not reduce the decrement in performance (P>0.05). Active heating strategies increased HR during HT in comparison to CON, whereas PH did not. During the HT period in the CON trial, T(c) decreased by 0.97+/-0.29 degrees C, PH and SSAH trials did not attenuate this decrease (P>0.01), whereas NSAH increased T(c) in respect to CON (P<0.01). These differences in HR and T(c) between re-warm-up strategies during HT were not apparent at the end of the trials. CONCLUSION: Active re-warm-up strategies during HT attenuated the decrement in second-half SSEP that was observed during passive trials.

Best practice in primary care pathology: review 1.

This first best practice review examines four series of common primary care questions in laboratory medicine, namely: (i) measurement and monitoring of cholesterol and of liver and muscle enzymes in patients in the context of lipid lowering drugs, (ii) diagnosis and monitoring of vitamin B12/folate deficiency, (iii) investigation and monitoring of paraprotein bands in blood, and (iv) management of Helicobacter pylori infection. The review is presented in a question-answer format, referenced for each question series. The recommendations represent a précis of guidance found using a standardised literature search of national and international guidance notes, consensus statements, health policy documents, and evidence based medicine reviews, supplemented by MEDLINE EMBASE searches to identify relevant primary research documents. They are not standards but form a guide to be set in the clinical context. Most are consensus rather than evidence based. They will be updated periodically to take account of new information.

Control of dynamic stability during gait termination on a slippery surface.

There are three common ways by which to successfully terminate gait: decreased acceleration of whole-body center of mass (COM) through a flexor synergy in the trail leg, increased deceleration of whole-body COM through an extensor synergy in the front limb, and an energy/momentum transfer to dissipate any remaining momentum if the first two strategies are unsuccessful. Healthy individuals were asked to stop on a slippery surface while we examined their unexpected response to the slippery surface. Kinetic data from the forceplates revealed lower braking forces in the slip trials compared with normal gait-termination trials. Subjects were unable to control their center of pressure (COP) to manipulate the COM as revealed by increased deviations and maximum absolute ranges of COP movement. Subject COM deviated farther in both horizontal planes and lowered further during the slip compared with normal gait-termination trials. Arm movements were effective in dissipating forward COM movement. In addition, there likely was a transfer of forward to lateral momentum to stop forward progression. All recorded muscle activity in the lower limbs and back increased during the slip to provide support to the lower limbs and correct upright balance. The trailing limb shortened its final step to provide support to the lowering COM. The balance-correction response seen here resembles previous reactions to perturbations during locomotion suggesting there is a generalized strategy employed by the nervous system to correct for disturbances and maintain balance.

The posterior subdeltoid approach: a modified access to the posterior glenohumeral joint.

A modified surgical approach to the posterior aspect of the glenohumeral joint and/or the dorsal glenoid is described. This access does not alter any muscle insertion or neuromuscular planes. After the skin incision is made, the inferior border of the spinal part of the deltoid is identified and the deltoid muscle is mobilized and retracted, thus offering an excellent approach to the interval between the infraspinatus and teres minor muscles. This interval is split parallel to the muscle fibers. This surgical approach was first established in 10 cadaverous shoulders and then performed in 12 patients with posterior shoulder pathology. In the cadaver study, the closest distance to the axillary nerve with this approach was 22 mm. In all 12 cases, the surgical procedure could be performed without any problems.

Characterizing human hand prehensile strength by force and moment wrench.

Characterizing human hand capabilities or demand created by various occupational tasks or activities of daily living has been mainly accomplished by measuring the maximum force exerted on a force dynamometer in a number of standard grips, for example power, key pinch and tip pinch grips. A framework is proposed instead to characterize human hand prehensile strength in generic form by describing external force and moment wrench capability, where a wrench is a vector describing the forces and moments applied at a point. It is further suggested that if tools and activities are characterized by the internal forces and external forces and moments required, a better understanding of the human prehension in occupational settings and during activities of daily living can be obtained. An example of using a pistol grip drill is used to show the utility of the approach.

Detection of oligonucleotide-ligand complexes by ESI-MS (DOLCE-MS) as a component of high throughput screening.

With the advent of combinatorial chemistry and high throughput screening, a major bottleneck in the pharmaceutical industry has changed from quickly finding active compounds to limiting them to a manageable number for proper follow-up. With hundreds to thousands of active compounds identified by a multitude of biological screens, there need to be rapid and unambiguous methods for eliminating false positive, toxic, or otherwise difficult compounds from further scrutiny. We have used electrospray ionization mass spectrometry as a rapid screening method to identify compounds from viral screens that yield a positive assay response by interaction with DNA rather than inhibiting the target enzyme. Both the sample preparation and data acquisition have been automated, allowing the screening of all hits from relevant biological screens (up to 1,000/week). The assay was validated using several known DNA intercalators and minor groove binders. These "standards" and many but not all of our "active compounds" were shown to form noncovalent complexes with a variety of different DNA:DNA and DNA:RNA duplexes.

Which stabilization technique corrects anatomy best in patients with AC-separation? An experimental study.

In ten human cadaveric shoulder specimens four different parameters were documented prior to, and after, dissecting all passive stabilizers. These included the vertical, horizontal and mediolateral acromioclavicular distance, as well as the clavicular rotation. In addition, the same parameters were documented after acromioclavicular (AC) reconstruction using eight different techniques. The results showed a good reconstruction of the vertical ac-distance. Most of the techniques, especially the coracoid-sling procedure, led to a significant anterior displacement of the clavicle in relation to the scapula. To a lesser degree, most of the conventional procedures also resulted in a lateralization of the acromion and/or clavicular rotation. A bone anchor system for distal fixation in the base of the coracoid process and a medialized hole in the clavicle restored anatomy best. This new technique therefore is recommended for anatomical AC-reconstruction.

Packed column supercritical fluid chromatography/mass spectrometry for high-throughput analysis.

A supercritical fluid chromatograph was interfaced to a mass spectrometer, and the system was evaluated for applications requiring high sample throughput. Experiments presented demonstrate the high-speed separation capability of supercritical fluid chromatography (SFC) and the effectiveness of supercritical fluid chromatography/mass spectrometry (SFC/MS) for fast, accurate determinations of multicomponent mixtures. A high-throughput liquid chromatography/mass spectrometry (LC/MS) analysis cycle time is reduced 3-fold using our general SFC/MS high-throughput method, resulting in substantial time saving for large numbers of samples. Unknown mixture characterization is improved due to the increased selectivity of SFC/MS compared to LC/MS. This was demonstrated with sample mixtures from a 96-well combinatorial library plate. In this paper, we report a negative mode atmospheric pressure chemical ionization (APCI) method for SFC/MS suitable for most of the components in library production mixtures. Flow injection analysis (FIA) also benefits from this SFC/MS system. A broader range of solvents is amenable to the SFC mobile phase compared with standard LC/MS solvents, and solutes elute more rapidly from the SFC/MS system, reducing sample carryover and cycle time. Finally, our instrumental setup allows for facile conversion between LC/MS and SFC/MS modes of operation.