Biomedical subjects

D Elliott

Publications and source records attributed to D Elliott.

At least 73 records · Page 4Linked to original sources

PubMed1998

Influence of spatial mapping on manual aiming asymmetries.

Two experiments were conducted to examine manual asymmetries in a one-dimensional aiming task. In Exp. 1, 10 right-handed adults slid a computer mouse 13 cm on a graphics tablet with both the right and left hands to targets of 3 different diameters. Under these conditions, the movement time for the right hand was significantly faster as expected. In Exp. 2, subjects performed similar movements to move a cursor 13 cm on a computer monitor. Thus the study was identical except the stimulus-response mapping was indirect. In this situation, there were no significant difference for either movement time or movement error between hands despite these performance measures indicating the target aiming was more difficult in Exp. 2. Because increases in task difficulty generally result in a greater advantage for the right hand, as indicated by Todor & Smiley, 1985, the present studies suggest that superiority of the right hand in aiming tasks may be diminished when spatial translation is required. Perhaps the spatial translation requires greater involvement of the right hemisphere, a process associated with manual advantage for the left hand, previously suggested by Roy and MacKenzie.

Adult↗

PubMed1997

Alcohol, tobacco and cannabis use among Nova Scotia adolescents: implications for prevention and harm reduction.

OBJECTIVE: To characterize adolescent drug use in terms of a risk continuum and to explore the rationale for harm reduction as a potential approach for school-based drug prevention. DESIGN: Self-reported surveys, in 1991 and 1996, of adolescent students concerning their use of drugs, especially alcohol, tobacco and cannabis, and the harmful consequences of such use. SETTING: Nova Scotia. PARTICIPANTS: A total of 3452 (in 1991) and 3790 (in 1996) junior and high school students in randomly selected classes in the public school system. OUTCOME MEASURES: Prevalence of drug use and patterns of multiple drug use and of alcohol- and drug-related problems; independent risk factors for multiple drug use. The risk continuum for the response to alcohol problems was used as a policy framework. RESULTS: The prevalence of cigarette smoking and the use of hallucinogens and stimulants was markedly higher in 1996 than in 1991. Over one-fifth (21.9%) of the students reported multiple drug use of alcohol and tobacco and cannabis in the 12 months before the 1996 survey. The 3 main subgroups--nonusers, users of alcohol only and users of multiple drugs--had distinct patterns of use, numbers of problems and risk factors. In all, 27.1% of the students had experienced at least 1 alcohol-related problem and 6% had experienced at least 1 drug-related problem in the 12 months before the 1996 survey. CONCLUSION: There is a need for integrated school- and community-based drug prevention programs, with goals, strategies and outcome measures capturing the full spectrum of patterns of use and levels of risk among subgroups of the adolescent student population.

Adolescent↗

PubMed1997

Hand, space and attentional asymmetries in goal-directed manual aiming.

Two experiments were conducted to explore the interaction of the two cerebral hemispheres in motor control, by examining hand, space and attentional asymmetries in goal-directed aiming. In Experiment 1, right-handed subjects moved to targets more quickly with their right hand than their left hand. In addition, each hand was faster when moving in its own hemispace. Although in a control condition, movements were initiated more quickly with the left hand, visual distractors disrupted left hand performance more than right hand performance. For contralateral aiming, ipsilateral distractors caused the greatest interference. In Experiment 2, when targets and distractors were all presented at the midline, a right hand advantage was found for movement time along with a left hand advantage for reaction time, independent of target and distractor location. Our findings are discussed in terms of a right hemisphere role in movement preparation and the allocation of attention in space, and greater left hemisphere involvement in movement execution.

Adolescent↗

PubMed1997

Costing intensive care services: a review of study methods, results and limitations.

Critical care services are an identified, resource-intensive component of health-care provision. Examining cost containment and clinical effectiveness in this specialty is therefore highly appropriate, although difficult to achieve in practice. The studies reviewed in this paper utilised various methodologies to capture different components of service and patient costs. The methods included combinations of per diem costs, hospital charges, direct consumption and unspecified cost estimates. Medical fees were commonly excluded and other costs, such as equipment and overheads, often not identified. Some more recent studies used clinical costing methods to capture individual patient-specific data, and demonstrated the feasibility and importance of these projects. Differing methods and data collection resulted in a limited comparative analysis, but issues requiring further research are highlighted. Funding of ICU services in Australia and nursing staff costs are also discussed. Future research will be aided by further sophistication in clinical information systems and the desire for clinicians to examine the link between costs and outcomes of the different activities pursued within the ICU.

Australia↗

PubMed1997

The gift relationship between pharmaceutical companies and physicians: an exploratory survey of physicians.

The purpose of this exploratory study was to survey physicians' attitudes surrounding the 'gift relationship' between pharmaceutical companies and physicians. A survey was mailed to 1000 randomly selected West Virginia physicians, of which 283 (28.3%) responses were received. The most commonly received gifts reported by the study physicians were trinkets (77.4%), followed by books (41.7%) and meals (41%). Principal component analysis and varimax rotation identified seven physician belief constructs. The mean ratings of the constructs indicated that the physicians slightly agreed that pharmaceutical companies give gifts to physicians to influence their prescribing, moderately disagreed that they do so as a form of professional recognition of physicians, and strongly disagreed that their prescribing behaviour could be influenced by the gifts they receive. Physicians slightly disagreed that pharmaceutical companies' sponsoring of CME programmes are only promotional gimmicks. Although the study physicians slightly disagreed that it may be inappropriate for them to accept gifts from pharmaceutical companies, they seemed slightly averse to having 'gift relationships' between pharmaceutical companies and physicians made public. Correlation analysis suggested that physicians who have a large number of patients in their practice, see a larger number of patients per day, or write a large number of prescriptions per day are more likely to be offered gifts by pharmaceutical companies, and they are also more likely to condone the practice of gift giving and receiving.

Attitude of Health Personnel↗

PubMed1997

I Lost It in the Lights: The Effects of Predictable and Variable Intermittent Vision on Unimanual Catching.

In this study, 2 competing views of interceptive action were examined by assessing the influence of variability in the interval between visual samples in a unimanual ball-catching task. Subjects were required to catch tennis balls projected over a distance of 14 m, under conditions of intermittent vision in which the between-sample intervals were either predictable or unpredictable. Results indicated that, although performance was best with shorter between-sample intervals, the temporal predictability of samples did not reliably affect catching performance. This suggests that between-sample retinal expansion provides sufficient information for the timing of the interceptive act.

catching↗

PubMed1997

A conjoint appointment involving a nursing research management role.

Nursing conjoint appointments have taken a number of different forms and included various hospital roles such as ward manager, educator and consultant. This paper discusses an appointment trialed at a lecturer/middle manager level with a functional hospital role of Assistant Director of Nursing (research). The hospital role included activities categorized as: research consultations; research proposal reviews; committee membership; and research project involvement. The academic activities included a half-time teaching load, student clinical placement supervision and thesis/treatise student supervision. The development and implementation of the position, including background, role structure, appointment conditions and work practices are discussed. Issues that were highlighted during the 2 year trial included: the teaching load compared to reimbursement funding; the actual activities involved in the position; the level of appointment required to be most effective in the role; and concomitant university study by the appointee.

Australia↗

PubMed1996

The granulomatous response in murine Schistosomiasis mansoni does not switch to Th1 in IL-4-deficient C57BL/6 mice.

IL-4 plays an important role in polarizing inflammation toward a Th2 response. It remains uncertain, however, whether IL-4 also serves to prevent expression of Th1 inflammation. Therefore, using a genetically pure C57BL/6 IL-4-deficient mouse, we studied the role of IL-4 in regulating the production of IFN-gamma and Th1 inflammation in the granulomas of mice infected with Schistosoma mansoni. In contrast to normal animals, IL-4 mutant mice generated smaller liver granulomas that contained fewer eosinophils and no mast cells. Collagenase-dispersed granuloma cells were analyzed by flow cytometry and cultured in vitro to measure cytokine and Ig production. Compared with control granuloma cells, IL-4-/- cells secreted only small quantities of IL-5 and IL-10. Also, there was impaired expression of the IL-4-dependent molecules IgE and IgG1 as well as B cell surface class II and CD23. Yet the granulomas of IL-4 -/- animals produced little IFN-gamma, IgG2a, or other molecules associated with Th1 inflammation even after Ag or anti-CD3 stimulation. Splenocytes from IL-4 -/- animals stimulated with schistosome Ag also failed to produce a Th1 response. Our data show that most aspects of the Th2 response in murine schistosomiasis are highly dependent on IL-4 production. But in the absence of IL-4, neither the natural local granulomatous response to schistosome ova nor the systemic response to soluble egg Ag switches to the type 1 phenotype. Thus the production of IL-4 early in the inflammatory response is not the only factor preventing Th1 expression in inflammation.

Animals↗

PubMed1996

T cell vasoactive intestinal peptide receptor subtype expression differs between granulomas and spleen of schistosome-infected mice.

Granulomas form in the liver and intestines of mice infected with the parasite Schistosoma mansoni. Vasoactive intestinal peptide (VIP) is a neurokine that can modulate aspects of the immune response by acting through receptors within the granuloma. Cloned are two novel VIP receptor (VIPR) mRNAs (VIPR1 and VIPR2) that also bind a second neurokine called pituitary adenylated cyclase-activating polypeptide (PACAP). The objective of this study was to determine if granulomas express either VIPR1 or VIPR2. Using a radioligand-binding assay, it was established that PACAP is as effective as VIP at displacing radiolabeled VIP from splenocytes and granuloma cells, and that most if not all VIPRs in the spleen and granulomas bind PACAP. PCR amplification of reverse transcribed RNA determined that granulomas express both VIPR1 and VIPR2 mRNAs. Gel electrophoresis and nucleotide sequencing confirmed the authenticity of the PCR products. Also, both receptor subtypes were amplified from several granuloma CD4+ T cell lines; yet reverse transcribed RNA from T cell-depleted, dispersed granuloma cells had only VIPR1 RNA. It is notable that reverse transcriptase-PCR detected only VIPR1 in the thymus and spleen, which are organs rich in T lymphocytes. Thus, the granulomas and spleens from mice with schistosomiasis contain cells that display authentic VIP/PACAP receptors. Moreover, these data suggest that T cells in different compartments vary in VIPR subtype expression. VIPR1 and VIPR2 may have different physiologic roles in inflammation.

Animals↗

PubMed1996

Local suppression of IFN-gamma in hepatic granulomas correlates with tissue-specific replication of Leishmania chagasi.

BALB/c mice are susceptible to infection with the visceralizing species of Leishmania, Leishmania chagasi. The parasite load initially rises in the liver and spontaneously subsides, whereas parasite multiplication begins later and remains lower in the spleen. To investigate whether this organ-specific multiplication of L. chagasi correlates with localized immune responses, we compared cytokine production by splenic vs hepatic immune cells. Livers from infected mice contained granulomas harboring intracellular L. chagasi amastigotes, whereas few amastigotes were present in the spleen. FACS analysis granuloma cells showed granuloma lymphocytes expressed a memory/effector phenotype. Granuloma cells cultured in vitro produced IL-10 and IL-6 but no detectable IFN-gamma, IL-4 or IL-5. In contrast, splenocytes from the same animals secreted IFN-gamma, IL-4, IL-6, and IL-10. T cells were depleted from granuloma cells by immune lysis, and the results indicated that IL-10 and IL-6 were derived at least in part from a non-T cell compartment. Paradoxically, FACS-purified Thy-1+ granuloma lymphocytes were able to produce IFN-gamma in the absence of other granuloma cells, suggesting IFN-gamma production might usually be inhibited by a granuloma-associated non-T cell element. Coculture of splenocytes with either granuloma cells or supernatants from granuloma cultures inhibited the usual splenocyte production of IFN-gamma and IL-4 but not IL-10. Thus, there may be a unique granuloma-associated suppressive factor accounting for the absence of IFN-gamma in hepatic granuloma cultures. It may be the absence of IFN-gamma in the liver and presence in the spleen that allows or inhibits parasite survival, respectively, in these different locations.

Animals↗

PubMed1996

What Models of Granulomatous Inflammation Provide the Immunologist

Granulomas usually serve to protect the host from the spread of persistent microorganisms or other enduring injurious substances. They are complex inflammatory reactions that use many immune mechanisms to control the inciting nudis. These lesions can persist for weeks, months, or even years. Thus, understanding the mechanisms that enhance, diminish, or modulate granulomas could aid in the treatment of many diseases. Moreover, experimental animal models of granulomatous inflammation allow sophisticated investigation of some disease processes not possible using human subjects. Granulomatous inflammations are chronic, composed of activated leukocytes that are selected for deposition at the site of injury. They use various effector mechanisms, delicately balanced by many immunoregulatory circuits. Under some experimental conditions, granulomas can be isolated readily from host tissue and subjected to sophisticated immunological analysis. Therefore, it is possible to dissect the actual, local control mechanisms that govern the granulomatous response. Lesions learned studying granulomas are applicable to other types of inflammation, since granulomas use immunoregulatory networks and soluble cytokines common to many inflammatory states. Using these experimental models, it is readily apparent that studies utilizing splenocytes or peripheral blood leukocytes may not reveal the true, dominant immunoregulatory mechanisms employed at sites of active inflammation. The leukocytes of spleens and blood are a mixture of cells in various stages of activation, many of which are not destined to participate in a selective immune response. Also, granulomas are sustained inflammatory reactions permitting analysis of the unique features of chronic maintenance, as opposed to acute phase inflammation.

Journal Article↗

PubMed1996

Substance P receptor antagonist inhibits murine IgM expression in developing schistosome granulomas by blocking the terminal differentiation of intragranuloma B cells.

Schistosome granulomas make substance P (SP). CP96,345 is a nonpeptide SP receptor antagonist active in vivo. Granulomas that form in the presence of SP receptor blockade produce little IgM as compared to normal lesions. The objective of this study was to determine how CP96,345 modulates granuloma IgM production. Schistosome ova were embolized to the lungs of infected mice to induce granulomas of synchronous age. Animals received CP96,345 (50 mg/kg/day) for 4 days following egg embolization. Then granulomas were isolated from tissue and dispersed into single-cell preparations. The dispersed granuloma cells were cultured in vitro to measure IgM and cytokine secretion. Also, granuloma B cells were studied using an IgM ELISPOT assay and flow cytometry. As expected, mice treated with CP96,345 formed granulomas that secreted little IgM. Granulomas from CP96,345-treated mice, as compared to buffer-treated animals, contained few IgM-secreting B lymphocytes, but had appropriate numbers of B cells expressing surface IgM. Also decreased was the capacity of the granulomas to make IFN-gamma, IL-4, IL-5 and IL-6. CP96,345 treatment did not affect splenocyte IgM or cytokine synthesis. These data suggest that CP96,345 inhibits granuloma IgM secretion by blocking intragranuloma B cell maturation at a terminal stage of B cell differentiation. Moreover, SP receptor antagonist affects a variety of cytokine circuits that could influence IgM B cell maturation in vivo.

Animals↗

PubMed1996

Basic life support skill acquisition and retention in student nurses undertaking a pre-registration diploma in higher education/nursing course.

Many studies have investigated the ability of health care professionals to provide competent Basic Life Support (BLS) and all results indicate that the majority of staff fail to demonstrate competence. However, it has not yet been shown whether this poor performance is due to deterioration of skill or the nonacquisition of the skill during BLS training. This study seeks to identify aspects of BLS acquisition and retention by student nurses during their three years of training. The two issues under consideration are the effect of teacher-student ratio and the effect of regular practice on BLS performance. This paper provides a review of the methodology and the initial findings.

Cardiopulmonary Resuscitation↗

PubMed1996

Radiofrequency ablation: a review of its application and nursing considerations.

Radiofrequency ablation (RFA), a therapeutic electrophysiological procedure, has become the treatment of choice for a number of cardiac arrhythmias. These arrhythmias include those of anomalous pathways, as seen in AV nodal re-entry tachycardia and Wolff-Parkinson-White syndrome, and re-entry tachycardias of atrial and ventricular origins. This paper discusses the mechanism of RFA and the physiology of re-entry circuits, and outlines the cardiac arrhythmias treated by RFA. The nursing responsibilities associated with the RFA procedure--including patient education, observation for potential complications, and other peri- and post-procedure considerations--are then addressed.

Arrhythmias, Cardiac↗

PubMed1996

Influence of object size on prehension in leukotomized and unleukotomized individuals with schizophrenia.

The aim of this study was to investigate the influence of schizophrenia and frontal leukotomy on the control and perceptual-motor coordination of reaching and grasping movements. Reaches to various-sized drinking glasses were videotaped for unleukotomized and leukotomized adults with schizophrenia, and for healthy age-matched controls. Kinematic analyses showed that while the two patient groups moved more slowly than the controls, the proportion of overall movement time spent accelerating to reach peak velocity and the proportion of overall movement time spent decelerating before contact with the glasses was similar for all three groups. For grasp formation, the two patient groups, which did not differ, opened their hands wider than did the controls; however, all three groups opened their hands to the appropriate size in response to the various glass sizes. The frontal lesions of the leukotomized patients were not related to motor control deficits when compared to the control schizophrenic patients. As well, the perceptual abilities of the patients were adequate as evidenced by their ability to scale their grasp to glass size.

Aged↗

PubMed1996

Specificity of learning and dynamic balance.

Contrary to a strict specificity of learning position, Robertson, Collins, Elliott, and Starkes (1994) have reported that the balance beam performance of expert gymnasts is less affected by the withdrawal of vision than is the performance of novice gymnasts. In this study, we employed a training paradigm in order to exercise complete control over the sensory conditions under which a dynamic balance beam task was acquired. Novice participants were trained either with or without vision to walk across a balance beam as quickly as possible and later tested in the other vision condition. Although participants improved more in the condition in which they trained, practice in one sensory condition did not negatively affect performance in a different sensory circumstance. The finding that vision was still extremely important after 5 days of practice is problematic for models of motor learning that propose a progression with learning from closed-loop to open-loop control.

Adult↗

PubMed1995

The preparation of aiming movements.

Three experiments are reported in which subjects made rapid aiming movements to visual targets with their left and right hands. In Experiments 1 and 3, a precue protocol was employed. In the "simple" reaction time condition, subjects were precued with complete information concerning the target position. In the four-choice condition, subjects were precued with partial information, indicating a subset of four possible target positions. In the eight-choice condition, advance information regarding the target position was entirely ambiguous. Results indicated that when subjects were provided with unspecific advance information concerning the position of the target, and thus were unable to partially prepare movements prior to the imperative stimulus, a left hand advantage for speed of initiation was obtained. When complete advance information was available, reaction times for the left and right hands were equivalent. The left hand advantage in choice conditions was eliminated when the accuracy of response execution was emphasized and subjects were afforded the opportunity for "on-line" preparation (Experiment 3). These data are discussed in relation to the role of the right hemisphere in the preparation of movement.

Adult↗

PubMed1995

Manual performance in leukotomized and unleukotomized individuals with schizophrenia.

Seven leukotomized adults with schizophrenia (LS), eight unleukotomized adults with schizophrenia (ULS), and eight healthy control (C) individuals were required to reach toward and grasp a small object that was either stationary or moving. Reflective markers were placed on the subject's index finger, thumb and wrist, and movements were videotaped. As expected the LS and ULS groups moved slower than the C group when the target was stationary. However, when the target was moving, all three groups moved faster, with the LS and C groups having the same movement times, and the ULS group having the fastest movement time. When the timing of the reaching trajectory was assessed, the LS group spent less time decelerating and closing their hands around the object, indicating their movements were controlled with less precision. When grasp formation was analyzed, for the stationary condition, the maximum apertures of the LS and ULS groups were not different, and both were larger than those of the C group. For the moving target condition, aperture increased for all groups but was smallest for the C group, intermediate for the LS group and largest for the S group. There was actually less within subject variability in peak aperture and maximum aperture closing speed for the LS and ULS groups in comparison to the C group, perhaps indicating a limited repertoire of potential motor responses for the patient groups. These results suggest that individuals with schizophrenia are able to use redundant information as well as controls, and that leukotomized individuals with schizophrenia have greater motor control deficits than unleukotomized schizophrenics.

Adult↗