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Biomedical subjects

B Elliott

Publications and source records attributed to B Elliott.

At least 37 records · Page 2Linked to original sources
PubMed1996

The role of upper limb segment rotations in the development of spin in the tennis forehand.

Increased topspin in the tennis forehand is produced by maintaining a perpendicular racket-face to the court surface at impact and increasing the trajectory and vertical velocity of the racket-head. These modifications to stroke technique from those previously identified in the flat forehand drive are the result of changes to the movement patterns of the segments of the upper limb. The contributions that the upper limb segment's anatomical rotations make to racket-head velocity at impact depend on both their angular velocity and the instantaneous position of the racket with respect to these movements. Six high performance tennis players were filmed at a nominal rate of 200 Hz by three Photosonics cameras while hitting flat (no spin) and topspin groundstrokes and a forehand topspin lob. The three-dimensional (3-D) displacement histories of 16 selected landmarks were then calculated using the direct linear transformation approach and 3-D individual segment rotations for the upper limb were calculated using vector equations. Significant differences were recorded in the effect that the various segment rotations made to the x-direction (forward) and y-direction (upward) impact velocities of the racket-head. These differences were not reflected in the contributions to racket-head velocity when the absolute velocities were expressed relative to the impact velocity. Trunk rotation, upper arm flexion/abduction, upper arm internal rotation, hand palmar and ulnar flexion all played integral roles in producing impact racket speed.

Adult↗
PubMed1996

Localization of platelet-derived growth factor beta receptor expression in the periepithelial stroma of human breast carcinoma.

Platelet-derived growth factor (PDGF) BB is secreted by most human breast carcinoma cells; however, only recently have PDGF beta receptors been demonstrated in malignant breast tissue. In the present study, the tissue localization of PDGF beta receptor expression was studied in human breast carcinoma and nonmalignant breast tissues stained using both immunofluorescence and immunoperoxidase techniques. We examined a total of 29 cases of breast carcinomas, which showed both in situ and invasive components. PDGF beta receptor staining was localized in the periepithelial stroma and was particularly intense in regions immediately adjacent to carcinoma in situ components in all tumors examined. A diffuse low level of PDGF beta receptor staining was seen throughout the stroma of eight nonmalignant breast tissues as well as of nonmalignant regions of tumor tissues. Image analysis was used to assess the coincidence of staining of PDGF beta receptor with epithelial or stromal cells in 13 of the 29 tumor tissues studied. Less than 5% of malignant ductal epithelium or myoepithelium showed PDGF beta receptor staining. Analysis with stromal cell type-specific markers indicated significant localization of PDGF beta receptor primarily within alpha smooth muscle actin-staining cells (32%) and vascular endothelial cells (41%) in the periepithelial stroma. PDGF beta receptor positivity was strongly associated with periepithelial stromal cells adjacent to the basement membrane surrounding regions of carcinoma in situ but was less intense in regions of invasive carcinoma where basement membrane was degraded. The absence of PDGF beta receptors on carcinoma cells and their presence in the surrounding stroma suggest a paracrine stimulation of adjacent stromal tissue by malignant epithelial cells in human breast tumors.

Actins↗
PubMed1995

A comparison of the high and low backspin backhand drives in tennis using different grips.

Three-dimensional, high-speed cinematography was used to compare backspin backhand techniques of high performance players hitting low (5.4 cm below hip height) and high (41.6 cm above hip height) bouncing balls using their preferred method of holding the racket (eastern backhand or continental grip: hand generally on top of the handle) and non-preferred ('behind the handle') grip. The Direct Linear Transformation method was used for three-dimensional space reconstruction from two-dimensional images recorded from laterally placed phase-locked cameras operating at 200 Hz. The only significant differences (P < 0.05) caused by the change in grip were that the ball was impacted further in front of the body when using the non-preferred grip, and a lower peak racket-shoulder speed was recorded for a high bouncing ball when using the non-preferred grip. Irrespective of the type of grip, the players significantly modified (P < 0.01) their technique to hit a high bouncing ball by adopting a more upright trunk, more rotated shoulder alignment (racket shoulder pointing more towards opponent), a larger front knee angle and a more abducted upper arm. Hitting a high ball was also characterized by a less inclined approach trajectory of the racket, a more vertical racket-face and a different speed profile for the segments of the upper limb and racket.

Acceleration↗
PubMed1995

A descriptive epidemiology of netball injuries during competition: a five year study.

OBJECTIVE: To investigate the relation between injury profiles - including assessment, treatment, severity, and the perceived reason for the injury - and participation in competitive netball. METHODS: Between 1985 and 1989, approximately 11,228 netball players participated in a 14 week netball competition held at the major competitive centre in Western Australia; 608 netball players presented to the first aid room with an injury and were assessed and treated by the same physiotherapist and St John First Aid officer. RESULTS: The overall incidence rate during competition was 5.4%, with more injuries occurring in the A grade level of play. Ankle injuries (84%) were most frequent, with 67% of these injuries diagnosed as lateral ligament sprains while a further 10% of players who suffered this classification of injury sustained a fracture to the ankle or foot. Few injuries occurred at the knee joint (8.3%) and only 1.8% of these injuries were diagnosed as an injury to the anterior cruciate ligament. The direct probability of a netball players' risk estimate was 0.054 per person per match which implied that netball was a relatively safe game. Injuries sustained during practice were not included in this study. CONCLUSIONS: Netball is a relatively safe game though the potential for injury increases with the level of competition.

Adolescent↗
PubMed1995

Health care for the uninsured in Duluth.

Providing health care for Minnesota's uninsured population continues to be both a clinical and political challenge. Between October 1, 1991, and September 30, 1993, 1,260 previously uninsured people received charity health care in Duluth. No one was excluded because of pre-existing conditions. Their utilization of services and associated costs can help project the health care needs and costs of care for uninsured Minnesotans. This group of uninsured people used a different mix of health care services compared with insured Minnesotans, and their total costs (including prescriptions) were about 15% greater. A large proportion of these uninsured Minnesotans had chronic health conditions and a "pent-up need" for services and medications. This experience demonstrated that it is possible to administer a limited benefits plan in coordination with existing public and private resources.

Adolescent↗
PubMed1995

Cultural diversity as a factor in self-monitoring blood glucose in gestational diabetes.

The routine use of self-monitoring of capillary blood glucose by pregnant diabetic patients currently provides the basis for both clinical management and ongoing investigation. Strategies must therefore be developed to ensure that these data are reliable and accurately reported by patients and are not influenced by diverse socioeconomic levels or varied geographic locations. To explore this issue, we used glucose reflectance meters with a memory microchip capable of storing up to 440 consecutive blood glucose determinations. Two diverse groups of women from Texas and New York who had gestational diabetes performed self-monitoring of blood glucose from diagnosis until delivery. Both groups recorded their blood glucose results daily in a logbook. The reporting performance of all the participating subjects resulted in an actual compliance rate of 60% to 70% of testings required of the patients. Comparison of African-American, Mexican-American, and white populations revealed no significant differences in patient performance or compliance. Moreover, no differences were found between the groups at different geographic locations (New York, Texas) in patients' willingness and ability to comply with the regimen of self-monitoring blood glucose. These findings suggest that the use of memory reflectance meters, in conjunction with patient education and positive interaction between patient and care provider, will result in high patient compliance regardless of socioeconomic level or ethnic diversity.

Adult↗
PubMed1994

A three-dimensional kinematic method for determining the effectiveness of arm segment rotations in producing racquet-head speed.

The contribution that a segment's anatomical rotations make to racquet-head speed depends on both the segment's angular velocity and the instantaneous position of the head of the racquet with respect to the segment's axes of rotation. Any analysis of racquet swing technique that does not consider both of these factors simultaneously is, at best, incomplete. With this in mind, a three-dimensional kinematic method was developed to determine the effectiveness of the anatomical rotations of the upper arm, forearm, and hand in producing racquet-head speed. The method entailed developing a system of vector equations for three-dimensional upper limb rotations that used displacement histories of 10 selected landmarks as input. The required three-dimensional displacement histories were obtained using three cine cameras and the DLT approach. To test the diagnostic capabilities of the method, a tennis serve was selected for analysis. For the player and serve analyzed, the greatest contribution to racquet-head speed at impact was produced by internal rotation of the upper arm (8 m s-1). Forearm pronation, although exhibiting the fastest rotation at impact (24 rad s-1), ranked only fourth in terms of its contribution (4 m s-1) to racquet-head speed. To test the performance of the method, a comparison was made between the racquet-head speed measured directly from film and the racquet-head speed computed by summing all of the individual segment contributions to speed commencing at the start of forward swing and ending at ball contact. The results indicate that the method can successfully determine the individual contributions that the different anatomical rotational velocities of the arm segments make to the measured instantaneous racquet-head speed.

Algorithms↗
PubMed1994

Role of hepatocyte growth factor in breast cancer: a novel mitogenic factor secreted by adipocytes.

Stromal cells can dramatically affect the growth and metastatic capability of breast carcinoma cells. Growth factors, considered to be important mediators of this process, act as either mitogenic or mito-inhibitory regulators. We have developed an in vitro coculture system to examine the influence of adipocytes, a dominant mammary stromal cell type, on the growth of a murine mammary carcinoma, SP1. Previously, we have reported that conditioned medium (CM) from 3T3-L1 adipocytes can promote in vitro growth of SP1 cells. We now show that the major mitogenic signal derived from 3T3-L1 adipocyte CM is mediated by hepatocyte growth factor (HGF). Neutralizing antibody against HGF at 15 micrograms/ml completely abrogated mitogenic activity of 3T3-L1 CM. Furthermore, heparin, an inhibitor of biological activity of HGF, inhibited the mitogenic activity of 3T3-L1 CM. Western blot analysis also confirmed the presence of HGF in 3T3-L1 CM. Although basic fibroblast growth factor (bFGF) and insulin-like growth factor I (IGF-I) were mitogenic for SP1 cells, neutralizing antibodies against IGF-I, bFGF, platelet-derived growth factor (PDGF), and epidermal growth factor (EGF) did not inhibit the mitogenic activity of 3T3-L1 CM. Immunoprecipitation and immunoblotting of HGF receptor/c-met showed that c-met is expressed at high level in SP1 cells, and is phosphorylated following HGF ligation. Together, our present data demonstrate that 3T3-L1 adipocytes secrete HGF, which stimulates SP1 cell growth by a paracrine mechanism. Furthermore, the mitogenic effect of 3T3-L1 CM requires HGF receptor ligation and activation of tyrosine kinase signaling cascades in SP1 cells. These results highlight the importance of stromal-tumor cell interactions and suggest that HGF secreted by adipocytes may be a key regulator of mammary tumor growth.

3T3 Cells↗
PubMed1994

A review of primary health-care organization.

A contract for the provision of community nursing and associated services was drawn up between the Plymouth Community Unit and general practitioners associated with a fundholding practice at a health centre in Devon in October 1991. This project, which aimed at applying purchaser/provider principles, contained some novel features and was subject to evaluation and review after 6 months. An evaluation which had four main aspects was carried out, consisting of interviews and questionnaire assessment of staff attitudes, patients' views of the effectiveness of aspects of the practice health-promotion activity, an analysis of staff activity data before and during the pilot phase and an examination of the documentation concerned with critical issues which had arisen. Questionnaire data indicated that staff motivation and enthusiasm for the project was high and that patients' views on the practice facilities were generally positive. The role of the Macmillan nursing service at this practice was greatly enhanced during the pilot project with a fourfold increase in the number of visits carried out. Over 120 h were spent by health visiting and district nursing staff on issues surrounding the pilot project including attending additional meetings. The results are discussed in relation to service benefits to patients, the effect on the cohesion of the primary health-care team and issues of fundholding and are considered in the context of models put forward for the future development of community-based nursing care.

Adult↗
PubMed1994

Foot types and lower limb injuries in elite netball players.

In assessing the foot types and lower limb injuries of elite netball players, the following summary seems warranted. Ninety percent of elite female netball players had symmetrical foot types for both feet and these players had experienced at least one lower limb injury. Only 7.6% players (N = 16) of the 204 players surveyed had never sustained a lower limb injury during their netball careers. Regardless of foot type, the injury history of these elite netball players presented with a total number of 449 injuries that occurred to both ankle joints (36%), one ankle joint (16%), both knee joints (6%), one knee joint (13%), shin soreness (18%), and retropatellar pain problems (11%). On further inspection, 55% of players experienced one to two lower limb injuries throughout their netball careers. Injured players showed that players with the pronating foot types with rearfoot abnormalities (57%) were the most commonly injured and that compensated rearfoot varus foot type presented the most lower limb injuries for all body sites.

Adolescent↗
PubMed1993

Stress resistance of yeast cells is largely independent of cell cycle phase.

Rapidly growing cells of Saccharomyces cerevisiae are sensitive to heat shock, while non-growing stationary phase cells are highly resistant. We find that slowly growing cells have an intermediate degree of heat shock resistance that can be nearly as great as that of stationary phase cells. This resistance is correlated both with slow growth and with carbon catabolite derepression. Slowly growing cells also showed resistance to Zymolyase digestion of their cell walls. The stress resistance is a property of all the cells in the culture, and cell cycle position makes little difference to the degree of stress resistance. At least some of the properties normally associated with stationary phase cells do not require residence in stationary phase or any other particular compartment of the cell cycle. Stress resistance may be due to a diverse set of physiological adaptations available to cells regardless of their position in the cell cycle. That is, although stress resistance and stationary phase are often correlated, neither is the cause of the other.

Amino Acids↗
PubMed1993

Dimensions and predictors of change during brief psychiatric hospitalization.

The effects of brief psychiatric hospitalization on patient functioning remain controversial and poorly defined. In this study, 217 subjects were evaluated for the changes they experienced during a brief admission (average length of stay 23.0 +/- 16.2 days). Significant improvements occurred in symptoms, global functioning, self-esteem, perceptions of others, and ego functioning. Better multidimensional outcome correlated with symptomatic improvement and preadmission functioning. No effects were found for age, gender, Axis I diagnosis, presence of an Axis II or Axis III disorder, prior hospitalization, severity of symptoms, length of stay, or payor group. During brief hospitalization, patients appear to improve in several areas of psychosocial functioning.

Adolescent↗
PubMed1993

Lower limb and back injury patterns of elite netball players.

The purpose of this study was to investigate the relationships between lower limb and back injuries with perceived landing patterns and podiatric variables for injured and uninjured elite netball players. 228 players of a possible 240 participants at the 1988 Australian netball championships completed injury questionnaires and were assessed for injury status. Approximately 92% of those who were part of the injury surveys were also given a podiatric assessment. Pearson chi 2 and unpaired t-tests were used to assess relationships between injury status in 2 groups (history of injury, and injuries sustained during the championships) and perceived landing patterns during play and podiatric variables. A significant association was found between history of lower limb and back injuries and level of competition. Open age netballers reported more injuries than the younger players. During each championship, a similar number of players (23%) were injured irrespective of playing level. 71% of these players sustained a grade 1 injury, 15.4% a grade 2 injury and 13.5% presented with severe grade 3 injuries. 2 players were diagnosed with an anterior cruciate ligament injury and a further 3 players sustained a fracture during the championships. Most of the injuries were ligamentous (40.5%) with some overuse tendinitis (11.5%) problems. The injury history profiles of the elite players surveyed showed that ankle and knee injuries were the most common lower limb injuries with incidences of 58 and 22%, respectively. More than a quarter of the players had overuse type injuries (24% retropatellar pain, 38% shin soreness) and 33% complained of back problems during their careers. 18 significant relationships were found between injuries sustained during a player's career and podiatric measures. Only 22.5% of a player's foot types were classified as normal while 42% presented with rearfoot varus and 20% were grouped into pronated foot postures.

Adolescent↗
PubMed1992

Modulation of growth factor responsiveness of murine mammary carcinoma cells by cell matrix interactions: correlation of cell proliferation and spreading.

We have examined the role of growth factors and extracellular matrix in the proliferation and cell adhesion of a murine mammary carcinoma, SP1, and a stable highly metastatic variant, SP1-3M. On fibronectin, both cell types proliferated strongly in response to basic fibroblast growth factor (bFGF) and platelet-derived growth factor BB (PDGF-BB) after culture for 24 h and 72 h. In contrast, on collagen type I, SP1 cells proliferated only weakly to PDGF-BB at either time, and SP1-3M cells showed a response to PDGF-BB only at 72 h. The proliferative response to bFGF was also consistently lower when the cells were cultured on collagen than on fibronectin. No significant proliferative responses were detected to epithelial growth factor (EGF), transforming growth factor-beta (TGF-beta), or estrogen on any substratum. The lack of responsiveness to PDGF-BB of cells cultured on collagen type I was not due to differences in numbers or affinity of PDGF receptors. We therefore examined the adhesion and spreading properties of SP1 and SP1-3M cells. Without exogenous growth factors, both cell lines adhered to fibronectin and laminin. SP1-3M cells did not bind to collagen type I, whereas SP1 cells did. Attachment to all three substrata was inhibited by anti-beta 1 integrin IgG, suggesting that the primary adhesion to these substrata is mediated by beta 1 integrins. SP1 and SP1-3M cells showed similar integrin patterns following immunoprecipitation by anti-beta 1 integrin IgG. bFGF stimulated increased adhesion and spreading of both SP1 and SP1-3M cells to collagen type I within 24 h, whereas PDGF-BB was less capable of this effect. Our results suggest that the proliferative response of SP1 and SP1-3M cells to PDGF-BB and bFGF is dependent on the extracellular matrix environment, and imply that modification of extracellular matrix and/or surface integrin receptors may regulate responsiveness to these growth factors in the SP1 tumor model.

Adenocarcinoma↗
PubMed1992

Landing patterns in netball: analysis of an international game.

The passing and landing patterns among netball players were investigated by examining all the 595 passes in an international match between Australia and New Zealand. Intra-class correlations were used to test inter-observer reliability. The independence of two variables was tested using a Pearson chi 2 test and a contingency coefficient was used to assess the degree of association between variables. An inter-rater reliability in the identification of movement patterns was 0.99. Most of the landings observed in this match were on the forefoot and not the hindfoot as generally reported in controlled experiments. Only 14% of the players leapt to receive a pass compared with 76% reported earlier under controlled environments. The distribution of passing techniques unexpectedly showed that approximately 50% of all the players did not reach for the ball as it was thrown directly to them. However, over 70% of the players threw straight passes which were mainly received in the chest quadrant and other types of passes such as loop, bounce and rebound were used less frequently. Nearly 50% of all players used a right-handed pass to dispose of the ball, while the next most popular pass was to use both hands (40.2%). Landing and passing patterns differed between players in different positions. Footfall patterns on landing after a catch were associated with the trajectory of the ball.

Australia↗
PubMed1991

From the patient's point of view: medical ethics and the moral imagination.

This paper concerns the difficulties of imagining the subjective point of view of another human being, and the relevance of these difficulties to medical decisions. It explores especially the difficulties of imagining the experience of the mentally impaired, and examines several standards for decision-making: the 'prior expressed wishes standard', the 'substituted judgement standard', and the 'best interests standard'.

Beginning of Human Life↗
PubMed1990

Fine body movements and the cardiac cycle in archery.

This study examined the relationships between postural sway, aiming time, the cardiac cycle time and the placement of the first finger movement within the electrocardiac cycle, with the quality of the arrow shot. A small group of elite male and female archers who shot either the recurve or the compound bow, freestyle or bare bow was used in this study. A total of 240 arrows were shot, classified as being of good, average or bad quality and analysed in detail. The analyses were undertaken over two occasions up to 100 days apart. The area of postural sway, as measured by the movement of the centre of pressure coordinates, varied significantly (P less than 0.05-0.001) both within and between trials for all archers and for all quality of arrows shot. There was a tendency for the area of postural sway to increase as the quality of the arrow shot decreased. This increase in postural sway exceeded, for arrows of bad quality, that exhibited as normal postural sway when standing relaxed and addressing the target with the hands at the side. Aiming time was variable within the quality of arrow shot, although it was consistent for each archer. In some cases the aiming time increased as the quality of the arrow decreased, whereas in the case of bare bow archery the aiming time tended to decrease as the quality of the arrow deteriorated. The cardiac cycle time increased significantly (P less than 0.05-0.01) as the archers approached the loose of the good quality arrows but there was no significant increase in cardiac cycle time when arrows of average or bad quality were shot. The most consistent parameter related to the quality of the shot was the placement of the first finger movement within the ST phase or the mid-cycle phase of the electrocardiogram for arrows of good quality (P less than 0.0001).

Adolescent↗