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Biomedical subjects

B Elliott

Publications and source records attributed to B Elliott.

At least 19 recordsLinked to original sources
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↗
PubMed1990

Maternal gonococcal infection as a preventable risk factor for low birth weight.

With the objective of determining if specific sexually transmitted diseases (STDs) are associated with prematurity (birth weight less than or equal to 2500 g and gestational age less than or equal to 36 weeks), a case-control study was conducted to evaluate women for serologic evidence of syphilis and human immunodeficiency virus infection and microbiologic evidence of cervical infection with Neisseria gonorrhoeae, Chlamydia trachomatis, and Haemophilus species and vaginal infection with genital mycoplasma, Streptococcus agalactiae, and Enterobacteriaceae. Gram stains of vaginal secretions were evaluated for bacterial vaginosis. Among 166 cases and 175 controls, infection with N. gonorrhoeae was associated with preterm birth. Four percent of controls and 11% of cases were infected with N. gonorrhoeae (odds ratio 2.9, 95% confidence interval 1.2-7.2). This association was independent of age, rupture of membranes, and hypertension. Other STDs were not associated with preterm birth. The attributable risk of gonococcal infection was 14%. Gonococcal infection appears to be responsible for a substantial proportion of premature births and is theoretically preventable by antenatal case detection and treatment.

Adult↗
PubMed1989

Planarians in toxicology. I. Physiology of sexual-only Dugesia dorotocephala: effects of diet and population density on adult weight and cocoon production.

A rare sexual-only race of Dugesia dorotocephala produces offspring from cocoons rather than by fissioning, allowing individuals to be accurately aged. Because each animal possesses fully developed male and female reproductive systems and a true brain with synapses, many types of toxicological studies which normally use vertebrates are possible with these animals. Prior to using this race for toxicological studies, a 3(3) factorial study was carried out to determine the effects of environmental conditions on reproduction and growth. The factors studied were crowding (2, 4, or 8 animals/50 ml medium), age (17, 19, 21 months), and type of dietary protein (soy, liver, cooked egg yolk). Protein composition dramatically affected the numbers of cocoons deposited per planarian, mean weight, and temporal patterns of weight changes. During 65 days of observation, planarians fed liver deposited an average of 3.28 cocoons/planarian while those fed soya or egg yolk deposited an average of 0.24 cocoon/planarian. Crowding, but not age, affected the numbers of cocoons deposited. Statistical analysis showed that protein composition, age, and crowding, alone and in factorial combinations, affected both the absolute weight changes and the temporal patterns in weight changes in each group.

Animals↗
PubMed1989

A biomechanical comparison of the topspin and backspin forehand approach shots in tennis.

Three-dimensional (3-D) high-speed cinematographic techniques were used to record topspin and backspin forehand approach shots hit down-the-line by high-performance players. The direct linear transformation (DLT) technique was used in the 3-D space reconstruction from 2-D images recorded via laterally placed phase-locked cameras operating at 200 Hz. A Mann-Whitney U-test was calculated for the different aspects of the topspin and backspin shots to test for significance (P less than 0.05). A significant difference was recorded between topspin and backspin shots in the angle of the racket at the completion of the backswing. The racket was taken 0.48 rad past a line drawn perpendicular to the back fence for topspin trials, but only rotated 0.86 rad from a line parallel to the net in the backspin shot. Maximum racket velocities occurred prior to impact and were significantly higher in topspin (26.5 m s-1) compared to backspin (16.6 m s-1) trials. This resulted in the topspin trials recording a significantly higher ball velocity compared to backspin trials (27.6 m s-1 vs 21.7 m s-1). Pre-impact racket trajectories revealed that in topspin shots the racket moved on an upward path of 0.48 rad while in backspin shots it moved down at an angle of 0.34 rad. In the topspin trials impact occurred significantly further forward of the front foot than in backspin shots (0.26 m vs 0.05 m) while the angle of the racket was the same for both strokes (0.14 rad behind a line parallel to the net). The mean angle of the racket-face at impact was inclined backwards by 0.11 rad for backspin strokes and rotated forward by 0.13 rad for topspin strokes. Angles of incidence and reflection of the impact between the ball and the court showed that backspin trials had larger angles of incidence and reflection than topspin strokes.

Adult↗
PubMed1989

Back injuries to fast bowlers in cricket: a prospective study.

Eighty-two high performance young male fast bowlers (mean age 16.8 years) were tested immediately prior to the season for selected kinanthropometric and physiological data. Subjects were also filmed both laterally (200 Hz) and from above (100 Hz) while bowling so that their front foot impacted a force platform during the delivery stride. The players then completed a log book over the ensuing season that detailed their training and playing programmes. All cricket related injuries over this season were assessed by a sports physician who used computerized tomography to assist in the diagnosis of spinal injuries. At the completion of this season the players were grouped according to their injury status (Group 1--bony injury to a vertebra; Group 2--soft tissue injury to the back that caused the player to miss at least one game, and Group 3--no injuries). A one-way analysis of variance was used to identify if any variables were significantly (P less than 0.05) different between the three groups, and a Scheffe post hoc comparison was used to determine which groups were significantly different. Eleven per cent of the players sustained a stress fracture to a vertebra(e) (L4 to S1), while 27 per cent sustained a soft tissue injury to the back. Bowlers with a low longitudinal foot arch were more likely to develop a stress fracture than those with a high arch. Shoulder depression and horizontal flexion strength for the preferred limb and quadriceps power in the non-preferred limb were also significantly related to back injuries. Results suggest that bowlers with the above physical characteristics, who bowl with these biomechanical techniques for extended periods, are predisposed to back injuries.

Adolescent↗
PubMed1987

Alteration of the tumorigenic and metastatic properties of neoplastic cells is associated with the process of calcium phosphate-mediated DNA transfection.

During the course of studies designed to assess the effect of human Ha-ras gene expression on the malignant behavior of transfected mouse tumor cells we noted that the process of Ca3(PO4)2-mediated DNA transfection was itself associated with profound alterations in tumorigenic or metastatic behavior. The cell line used as a recipient for these studies was a tumorigenic nonmetastatic CBA/J mouse mammary adenocarcinoma line called SP1. When cotransfected with plasmids containing the neo gene (pSV2neo) and the activated Ha-ras gene (pT24-c3), cells from the pooled (5-10 colonies) G418-resistant colonies gave rise to spontaneous lung metastases in 85% of mice after subcutaneous inoculation. However, we noted that 17% of control mice inoculated with G418-resistant pSV2neo-transfected SP1 cells also had lung metastases and that this number approached 100% as the inoculum comprised a greater pool size (50-100 colonies). When cell lines established from isolated pSV2neo-transfected colonies were examined, 3/16 were found to be metastatic. We also found that 3/16 clones grew slowly, or not at all, in CBA/J mice, whereas they grew readily in athymic (nude) mice. The increase in immunogenicity of two out of three of these latter clones was accompanied by expression of the class I H-2Dk major histocompatibility complex antigen that was not detectable in the parental SP1 cells. At least some of these results would appear to be due to exposure to Ca3(PO4)2 alone, as we found that it resulted in 5/20 (25%) clones manifesting metastatic properties. Our results suggest that heritable changes in malignant behavior of transfected tumor cells can be observed at high frequency subsequent to the process of Ca3(PO4)2-mediated DNA transfection, and these changes may be brought about in part by inherited disturbances in expression of recipient cell genes.

Adenocarcinoma↗
PubMed1979

Pathological cell aggregates in bone marrow cultures from patients with various hematological diseases.

Non-clonal growth of macroscopic cell aggregates in methylcellulose cultures of abnormal marrow is described. They were seen in all patients with Graft-versus-Host Disease, graft rejection, and autoimmune disease presumably directed against hemopoietic cells, we found them in 35% of patients with primary hematological neoplasias and rarely in patients with solid tumors. They were never encountered in 80 healthy controls. The aggregates originated from small cell clumps which sedimented with the "buffy coat" in contrast to normal bone marrow particles. They contained tumor cells, grafted myeloid cells, or target cells of autoimmune disease in association with a widely varying amount of macrophages. Preliminary results suggest that the frequency of macrophages within the aggregates correlates inversely with the aggressiveness of the clinical condition. We propose that appearance of such aggregates in an indicator of immune activation; we expect that further quantitation of the phenomenon will reveal important clinical correlations and provide a model for the study of host defense to "foreign" cells.

Anemia, Hemolytic, Autoimmune↗
PubMed1979

Patients' reactions to a two-way mirror in general practice.

From a survey of 200 patients in two general practices it would appear that the patients' reaction to the use of a two-way mirror is on the whole not unfavourable. The results suggest, however, that in the very personal setting expected of general practice people suffering from psychiatric problems (especially depression) should be given every opportunity to decline consultation in front of the mirror and if any patient becomes upset, then the mirror should be 'turned off' immediately. Internal examinations should not take place when the mirror is in use.

Attitude↗
PubMed1978

Mortality trends in the surgical management of chronic peptic ulceration: 25 years' experience.

This study is of the results of surgical management of bleeding chronic peptic ulceration at Prince Henry's Hospital, retrospective for the periods 1951 to 1960 and 1961 to 1970 and prospective for 1972 to 1977. During the latter five years all patients were admitted from the community to a haematemesis and melaena unit with a defined policy of management and prospective data recording for computer analysis. There was a continuing improvement in mortality over this 25-year period, especially with duodenal ulcer. No clear distinction could be made between conservative surgery and partial gastrectomy in terms of reduced surgical mortality in duodenal ulcer. Bleeding gastric ulcer remains a difficult problem, with a current surgical mortality of 21%.

Adolescent↗