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Biomedical subjects

A Lees

Publications and source records attributed to A Lees.

At least 55 records · Page 3Linked to original sources
PubMed2000

Understanding and measuring coordination and control in kicking skills in soccer: implications for talent identification and skill acquisition.

In this review, we explore the role of motor control and biomechanics in developing an understanding of soccer skills using kicking as the main vehicle. The links between these sub-disciplines of sport science have not been well established in the past because of an emphasis on cognitive processes in traditional accounts of motor behaviour. We argue that a dynamical systems interpretation of the processes of coordination and control in movements with multiple degrees of freedom signals a new era in the relationship between the sub-disciplines of motor control and biomechanics. Although research on coordination and control of soccer skills is currently sparse, there are indications that the relationship between motor control and biomechanics could form a significant component of scientific programmes in talent identification and skill development. Further interdisciplinary work is needed to enhance understanding of coordination and control of soccer skills.

Biomechanical Phenomena↗
PubMed2000

The functional demands on the intact limb during walking for active trans-femoral and trans-tibial amputees.

The aim of this study was to investigate the loading demands placed on the intact limb in terms of joint moments and power for active trans-femoral and trans-tibial amputees in comparison to a group of able-bodied subjects. Four (4) trans-tibial, 4 trans-femoral amputees and 10 able-bodied subjects walked at 1.2m.s(-1) along a walkway whilst kinematic data from both the intact and prosthetic limbs, and kinetic data from the intact limb only were collected. A Panasonic VHS video camera was used to film subjects walking in the sagittal plane with simultaneous force data collected from a Kistler force platform. The amputees were found to compensate for the functional loss of one or more joints by increasing net joint moments and power output on their intact limb compared to able-bodied subjects. At the intact limb ankle, the range of motion, peak dorsiflexor moment and power generation at toe-off increased. At the intact limb knee, power generation during stance and extensor moments and power absorption at toe-off increased. At the intact limb hip, extensor moment and power absorption during stance, and hip flexor moment and power generation at toe-off increased. These findings were partly attributed to the prostheses used but mainly to adaptation mechanisms displayed by trans-femoral and trans-tibial amputees. They have implications for the mobility of amputees and the long term health of their joints. It was recommended that prosthesis design, prosthesis fitting and training in the use of the prosthesis were all factors which could be investigated with a view to minimising intact limb loading.

Adult↗
PubMed2000

A comparison between written, verbal, and videotape oral hygiene instruction for patients with fixed appliances.

The objective of the study was to compare the effectiveness of written, videotape, and one-to-one instruction upon the knowledge, oral hygiene standard, and gingival health of subjects undergoing orthodontic treatment with a lower fixed appliance. Subjects for whom fixed appliances had been fitted recently were divided randomly into three groups of 21, 22, and 22, respectively. Group 1 received written oral hygiene instruction, group 2 a specially made videotape, and group 3 saw a hygienist for one-to-one instruction. Results were assessed in terms of improvement in knowledge concerning oral hygiene procedures, and of plaque and gingival index scores. Analysis of variance revealed no significant main effects or interactions at P = 0.05, although the difference in the plaque index scores before and after instruction was close to significance.

Analysis of Variance↗
PubMed2000

What clinical features are most useful to distinguish definite multiple system atrophy from Parkinson's disease?

OBJECTIVES: Few studies have attempted to identify what premortem features best differentiate multiple system atrophy (MSA) from Parkinson's disease (PD). These studies are limited by small sample size, clinical heterogeneity, or lack of postmortem validation. We evaluated the sensitivity and specificity of different clinical features in distinguishing pathologically established MSA from PD. METHODS: One hundred consecutive cases of pathologically confirmed PD and 38 cases of pathologically confirmed MSA in one Parkinson's disease brain bank were included. All cases had their clinical notes reviewed by one observer (AH). Clinical features were divided into two groups: those occurring up to 5 years after onset of disease and those occurring up to death. Statistical analysis comprised multivariate logistic regression analysis to choose and weight key variables for the optimum predictive model. RESULTS: The selected early features and their weightings were: autonomic features (2), poor initial levodopa response (2), early motor fluctuations (2), and initial rigidity (2). A cut off of 4 or more on the ROC curve resulted in a sensitivity of 87.1% and specificity of 70.5%. A better predictive model occurred if the following features up to death were included: poor response to levodopa (2), autonomic features (2), speech or bulbar dysfunction (3), absence of dementia (2), absence of levodopa induced confusion (4), and falls (4). The resulting ROC curve based on individual scores showed a best cut off score of at least 11 of 17 (sensitivity 90.3%, specificity 92.6%). CONCLUSIONS: Predictive models may help differentiate MSA and PD premortem. Hitherto poorly recognised features, suggestive of MSA, included preserved cognitive function and absence of psychiatric effects from antiparkinsonian medication. Diagnostic accuracy was higher in those models taking into account all clinical features occurring up to death. Further studies need to be based on new incident cohorts of parkinsonian patients with subsequent neuropathological evaluation.

Adult↗
PubMed1999

Population based cost utility study of interferon beta-1b in secondary progressive multiple sclerosis.

OBJECTIVE: To evaluate the cost utility of interferon beta-1b in secondary progressive multiple sclerosis. DESIGN: Population based cost utility model (healthcare perspective). Data on use of health services were obtained from case records and routine morbidity data and utility values from a EuroQol survey. Local and published costs were used. Effectiveness was modelled using data on relative risk reductions from a randomised trial of interferon beta-1b. SETTING: Tayside region, 1993-5. SUBJECTS: 132 ambulatory people with secondary progressive multiple sclerosis. MAIN OUTCOME MEASURES: Cost per quality adjusted life year (QALY) gained. Rate of relapse and proportion becoming wheelchair dependent over three years. RESULTS: The number needed to treat for 30 months to delay time to wheelchair dependence in one person by nine months was 18 (95% confidence interval 5 to 26). For every 18 people treated for 30 months, six relapses would be prevented, gaining 0.397 discounted QALYs. The cost per QALY gained was 1 024 667 pounds sterling (276 466 pounds sterling to 485 499 pound sterling). If treatment was restricted to patients attending neurology services, the number needed to treat was 14 (cost per QALY gained 833 pounds sterling 514 (161 358 pounds sterling to infinity)). The cost per QALY gained was not sensitive to changes in cost which took account of a societal perspective. CONCLUSIONS: The cost per QALY gained from interferon beta is high because of the high drug cost and modest clinical effect. Resources could be used more efficiently elsewhere.

Activities of Daily Living↗
PubMed1999

In vivo polysaccharide-specific IgG isotype responses to intact Streptococcus pneumoniae are T cell dependent and require CD40- and B7-ligand interactions.

In vivo Ig responses to soluble, haptenated polysaccharide (PS) Ags are T cell independent and do not require CD40 ligand (CD40L). However, little is known regarding the regulation of in vivo PS-specific Ig responses to intact bacteria. We immunized mice with a nonencapsulated, type 2 Streptococcus pneumoniae (R36A) and compared the parameters that regulated in vivo Ig isotype responses to the bacterial cell wall C-PS determinant, phosphorylcholine (PC), relative to Ig responses to the cell wall protein, pneumococcal surface protein A. Consistent with previous reports using soluble PS and protein Ags, the anti-PC and anti-pneumococcal surface protein A responses differed in that the anti-PC response was induced more rapidly, had a distinctive Ig isotype profile, and failed to demonstrate boosting upon secondary challenge with R36A. However, in contrast to previous studies, the IgG anti-PC response was TCR-alphabeta+ T cell dependent, required CD40L, and was blocked by administration of CTLA4 Ig. The nature of the T cell help for the anti-PC response had distinct features in that it was only partially blocked by CTLA4 Ig and was dependent upon both CD4+ and CD8+ T cells. Surprisingly, whereas the IgM anti-PC response was largely T cell independent, a strong requirement for CD40L was still observed, suggesting the possibility of an in vivo T cell-independent source for CD40L-dependent help. These data suggest that the regulatory parameters that govern in vivo Ig responses to purified, soluble PS Ags may not adequately account for PS-specific Ig responses to intact bacteria.

Animals↗
PubMed1999

Clinical genetics of familial progressive supranuclear palsy.

Recent studies have shown that progressive supranuclear palsy (PSP) could be inherited, but the pattern of inheritance and the spectrum of the clinical findings in relatives are unknown. We here report 12 pedigrees, confirmed by pathology in four probands, with familial PSP. Pathological diagnosis was confirmed according to recently reported internationally agreed criteria. The spectrum of the clinical phenotypes in these families was variable including 34 typical cases of PSP (12 probands plus 22 secondary cases), three patients with postural tremor, three with dementia, one with parkinsonism, two with tremor, dystonia, gaze palsy and tics, and one with gait disturbance. The presence of affected members in at least two generations in eight of the families and the absence of consanguinity suggests autosomal dominant transmission with incomplete penetrance. We conclude that hereditary PSP is more frequent than previously thought and that the scarcity of familial cases may be related to a lack of recognition of the variable phenotypic expression of the disease.

Adult↗
PubMed1999

Multivalent cross-linking of membrane Ig sensitizes murine B cells to a broader spectrum of CpG-containing oligodeoxynucleotide motifs, including their methylated counterparts, for stimulation of proliferation and Ig secretion.

We have previously reported that B cells that are activated by multivalent but not bivalent membrane Ig cross-linking ligands synergize with various B cell activators culminating in enhanced B cell proliferation. In this study we asked whether B cells that are activated by a multivalent mIg cross-linking agonist could respond to oligodeoxynucleotides (ODN) containing non-stimulatory motifs. Earlier reports have shown that ODN containing a CpG motif in which the cytosine is unmethylated and is flanked by two 5' purines and two 3' pyrimidines induce high levels of B cell activation, while ODN whose CpG are methylated or flanked by sequences other than the optimal two 5' purines and two 3' pyrimidines were non-stimulatory. In this manuscript we show that when B cells are stimulated in vitro with dextran-conjugated anti-IgD antibodies (anti-IgD-dex), as the multivalent mIg ligand, their proliferation is enhanced and they can be induced to secrete Ig in response to ODN containing various non-optimal motifs, both methylated and non-methylated. Furthermore we could induce synergistic levels of proliferation with concentrations of anti-IgD-dex that were in the picomolar concentration range and with concentrations of ODN that were 10- to 100-fold less than previously reported to be necessary for mitogenic activity. These data provided a model to explain how low concentrations of a multi-epitope-expressing microorganism in the context of mammalian (methylated) or microorganism (non-methylated) DNA can lead to dysregulated B cell proliferation and Ig secretion.

Animals↗
PubMed1999

Late onset startle induced tics.

Three cases of late onset Gilles de la Tourette's syndrome are presented. The motor tics were mainly induced by an unexpected startling stimulus, but the startle reflex was not exaggerated. The tics developed after physical trauma or a period of undue emotional stress. Reflex tics may occur in Gilles de la Tourette's syndrome, but have not been described in late onset Tourette's syndrome. Such tics must be distinguished from psychogenic myoclonus and the culture bound startle syndromes.

Adult↗
PubMed1999

Children's attitudes toward interacting with peers with different craniofacial anomalies.

OBJECTIVE: This study was designed to evaluate children's understanding of different craniofacial anomalies and their willingness to interact with children with such anomalies. DESIGN: This was a between-measures design in which children were randomly allocated to one of three groups. Each group viewed one of three pairs of computer-generated images (nondistinctive, cleft lip, or misshapen nose) of similar-aged children. SETTING: Participants were recruited from two city elementary schools and were interviewed at their schools. PARTICIPANTS: A total of 100 children (aged 7 to 10 years) entered the study, and complete sets of data were obtained for each child. As the majority of the children were white (n = 92), the nonwhite children (n = 8) were excluded from the data analyses. MAIN OUTCOME MEASURES: Participants were asked a number of questions to ascertain their thoughts about the image, and measures were then taken of each child's willingness to interact with the stimulus child. RESULTS: There were no significant differences between the three groups. Boys were significantly more willing to interact with the stimulus images than were girls, and there was a nonsignificant trend for girls to be more likely to spontaneously mention the craniofacial anomaly. Participants gave varied explanations for the condition's causation. CONCLUSIONS: Boys and girls differed in their willingness to interact with unfamiliar peers with and without facial distinctions. Various explanations were given to explain causality of the anomaly. Findings lend some support to the proposal that high "background attractiveness" can overshadow the impact of a craniofacial anomaly.

Analysis of Variance↗
PubMed1999

Biochemical assessment of individual sports for improved performance.

Biomechanists are able to offer a scientific service which aids the process of achieving improved sports performance. They are able to provide measurement tools to quantify key mechanical variables related to performance. Biomechanists use different methods to define these key variables, although there is no generally accepted approach on how this should be done. The process of intervention should be undertaken using information gained from a biomechanical assessment. This is often not conducted by the biomechanist and is usually left to other specialists. The success of this intervention is rarely evaluated so as to provide evidence to validate the earlier stages of the assessment. Biomechanists who have considerable experience and have conducted applied research programmes with specific sports seem to be able to demonstrate success. It is concluded that biomechanists need to support their claim to be able to influence performance outcome with more evidence based practice.

Biomechanical Phenomena↗
PubMed1998

Efaroxan, an alpha-2 antagonist, in the treatment of progressive supranuclear palsy.

We have tested, in a prospective randomized, double-blind, placebo-controlled, crossover, 12-week study, the effects of 2 mg efaroxan, a potent alpha-2 antagonist, given three times per day to 14 patients with progressive supranuclear palsy. Efaroxan did not induce any significant change on any motor assessment criteria. The present data do not confirm the assumption that the blockade of alpha-2 receptors might be a useful pharmacologic strategy to improve patients with progressive supranuclear palsy.

Adrenergic alpha-Antagonists↗
PubMed1998

A study of the reproducibility of three different normalisation methods in intramuscular dual fine wire electromyography of the shoulder.

The purpose of this study was to determine the most appropriate method of normalisation for dual fine wire electromyography of shoulder muscles. Five healthy subjects were studied, with one muscle investigated in each subject (2 supraspinatus, 2 infraspinatus, 1 subscapularis). Three dual fine wire electrodes were inserted 1 cm apart around the recognised insertion points. Each subject performed five types of cyclic exercise on an isokinetic muscle dynamometer with an isometric maximal voluntary contraction (MVC) being performed before and after the exercise protocol. The EMG signal was normalised using each of the MVC voltage, the peak voltage and the whole-cycle mean voltage. There was a considerable difference (5-143%) between the MVC signals pre- and post-protocol, although no systematic trend was demonstrable. The overall mean between electrode variation in the normalised signal measured at the peak of the cycle ranged from 48-71% when normalised to pre-protocol MVC, but only 4-13% when normalised to the peak voltage and 9-17% using the whole-cycle mean voltage. However the pattern of activation within the movement cycle, which was preserved by normalisation using the peak or mean signal, was consistent between different electrode positions. It was concluded that the EMG signal depended on electrode position even when near the recognised insertion point, and that the MVC signal is highly variable in magnitude between electrodes and between pre- and post-protocol measurements.

Adult↗
PubMed1998

Panniculitis in association with apomorphine infusion.

This study was undertaken to ascertain the histopathology and aetiology of cutaneous nodules observed in Parkinson's patients treated with continuous subcutaneous apomorphine. Ten patients were recruited, answered questionnaires, and underwent skin biopsies and full blood count, and nine were patch tested to apomorphine and its preservative. Six had serum IgE levels measured. A florid panniculitis was seen in all biopsies; five were predominantly eosinophilic, three lymphocytic and two neutrophilic; in seven cases the panniculitis was mixed and in three it was septal. Patch testing was universally negative and the IgE levels were normal.

Antiparkinson Agents↗
PubMed1998

Kinematics of running on 'off-road' terrain.

It has been established that running on natural 'off-road' terrain elicits a higher energy demand than running on road. Running on such terrain may also result in changes to the characteristics of the normal running stride. The aim of this study was to investigate biomechanical alterations to stride characteristics during off-road running. Nine female participants were recorded on video while running over three terrain types: surfaced footpath, short grass and long grass. The videos were digitized in order to quantify temporal, displacement and velocity variables. Cycle time was not significantly different between conditions (p = 0.315). Step length decreased (p < 0.01) and both vertical displacement of the hip and knee lift increased significantly (p < 0.01) with increasing difficulty of terrain. Despite assisted pacing, there was a significant decrease in velocity (p < 0.01) with each progressively rougher terrain condition. The peak extension angular velocity of the knee was not affected significantly (p < 0.098) by the terrain despite the fact that there was a significant difference in the peak flexion angular velocity (p < 0.01). It was concluded that participants altered their stride displacement and velocity patterns significantly in response to changes in running surface.

Adult↗
PubMed1998

The biomechanics of soccer: a review.

This review considers the biomechanical factors that are relevant to success in the game of soccer. Three broad areas are covered: (1) the technical performance of soccer skills; (2) the equipment used in playing the game; and (3) the causative mechanisms of specific soccer injuries. Kicking is the most widely studied soccer skill. Although there are many types of kick, the variant most widely reported in the literature is the maximum velocity instep kick of a stationary ball. In contrast, several other skills, such as throwing-in and goalkeeping, have received little attention; some, for example passing and trapping the ball, tackling, falling behaviour, jumping, running, sprinting, starting, stopping and changing direction, have not been the subject of any detailed biomechanical investigation. The items of equipment reviewed are boots, the ball, artificial and natural turf surfaces and shin guards. Little of the research conducted by equipment manufacturers is in the public domain; this part of the review therefore concentrates on the mechanical responses of equipment, player-equipment interaction, and the effects of equipment on player performance and protection. Although the equipment has mechanical characteristics that can be reasonably well quantified, the player-equipment interaction is more difficult to establish; this makes its efficacy for performance or protection difficult to predict. Some soccer injuries may be attributable to the equipment used. The soccer boot has a poor protective capability, but careful design can have a minor influence on reducing the severity of ankle inversion injuries. Performance requirements limit the scope for reducing these injuries; alternative methods for providing ankle stability are necessary. Artificial surfaces result in injury profiles different from those on natural turf pitches. There is a tendency for fewer serious injuries, but more minor injuries, on artificial turf than on natural turf pitches. Players adapt to surface types over a period of several games. Therefore, changing from one surface to another is a major aetiological factor in surface-related injuries. Heading the ball could lead to long-term brain damage. Simulation studies suggest the importance of ball mass, ball speed and player mass in affecting the severity of impact. Careful instruction and skill development, together with the correct equipment, is necessary for young players. Most applications of biomechanical techniques to soccer have been descriptive experimental studies. Biomechanical modelling techniques have helped in the understanding of the underlying mechanisms of performance, although their use has been limited. It is concluded that there are still many features of the game of soccer that are amenable to biomechanical treatment, and many opportunities for biomechanists to make a contribution to the science of soccer.

Athletic Injuries↗
PubMed1998

Enhanced protective antibody responses to PspA after intranasal or subcutaneous injections of PspA genetically fused to granulocyte-macrophage colony-stimulating factor or interleukin-2.

Antibody to pneumococcal surface protein A (PspA) has been shown to be protective for Streptococcus pneumoniae infections in mice. In an attempt to define a model for inducing protective antibody to PspA in the absence of adjuvant, we designed two genetic fusions, PspA-interleukin-2 [IL-2]) and PspA-granulocyte-macrophage colony-stimulating factor (GM-CSF). These constructs maintained high cytokine function in vitro, as tested by their activity on IL-2 or GM-CSF-dependent cell lines. While intranasal immunization with PspA induced no detectable anti-PspA response, both PspA-IL-2 and PspA-GM-CSF stimulated high immunoglobulin G1 (IgG1) antibody responses. Interestingly, only the PspA-IL-2, not the PspA-GM-CSF, construct stimulated IgG2a antibody responses, suggesting that this construct directed the response along a TH1-dependent pathway. Comparable enhancement of the anti-PspA response with similar isotype profiles was observed after subcutaneous immunization as well. The enhancement observed with PspA-IL-2 was dependent on IL-2 activity in that it was not seen in IL-2 receptor knockout mice, while PspA in alum induced high-titer antibody in these mice. The antibody was tested for its protective activity in a mouse lethality model using S. pneumoniae WU-R2. Passive transfer of 1:90 dilutions of sera from mice immunized with PspA-IL-2 and PspA-GM-CSF elicited protection of CBA/N mice against intravenous challenge with over 170 50% lethal doses of capsular type 3 strain WU2. Only 0.17 microg or less of IgG antibody to PspA was able to provide passive protection against otherwise fatal challenge with S. pneumoniae. The data demonstrate that designing protein-cytokine fusions may be a useful approach for mucosal immunization and can induce high-titer systemic protective antibody responses.

Administration, Intranasal↗