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Biomedical subjects

D Elliott

Publications and source records attributed to D Elliott.

At least 19 recordsLinked to original sources
PubMed2006

Clinical leadership in contemporary clinical practice: implications for nursing in Australia.

BACKGROUND: Leadership in the clinical practice environment is important to ensure both optimal patient outcomes and successive generations of motivated and enthusiastic clinicians. AIM: The present paper seeks to define and describe clinical leadership and identify the facilitators and barriers to clinical leadership. We also describe strategies to develop clinical leaders in Australia. Key drivers to the development of nursing leaders are strategies that recognize and value clinical expertise. These include models of care that highlight the importance of the nursing role; evidence-based practice and measurement of clinical outcomes; strategies to empower clinicians and mechanisms to ensure participation in clinical decision-making. KEY ISSUES: Significant barriers to clinical leadership are organizational structures that preclude nurses from clinical decision making; the national shortage of nurses; fiscal constraints; absence of well evaluated models of care and trends towards less skilled clinicians. CONCLUSIONS: Systematic, strategic initiatives are required to nurture and develop clinical leaders. These strategies need to be collegial collaborations between the academic and health care sectors in order to provide a united voice for advancing the nursing profession.

Australia↗
PubMed2006

The impact of an ICU liaison nurse on discharge delay in patients after prolonged ICU stay.

The mismatch between intensive care unit (ICU) bed availability and demand may be improved with timely patient discharges, however little is known about the nature and contributing factors of discharge delays. This study investigated the impact of a specific intervention--the ICU liaison nurse role--in reducing ICU discharge delay using a prospective block intervention study. One hundred and eighty-six ICUpatients (101 control and 85 liaison nurse intervention) with an ICU length of stay of three days or longer and who survived to ICU discharge were examined. The liaison nurse was involved in assessment of patients for transfer to the ward, with a major focus on coordinating patient transfer including liaison with ward staff prior to and following ICU discharge. Logistic regression was used to quantify the risk of discharge delay associated with the liaison nurse intervention with adjustment for potential confounding variables. While no demographic or clinical variables were significant predictors of ICU discharge delay, those in the liaison nurse group were almost three times less likely to experience a discharge delay of at least two hours and about 2.5 times less likely to experience a delay of four or more hours. The positive effect of the liaison nurse role in reducing the discharge delay remained after adjustingforpotential confounders. We conclude that the liaison nurse role is effective in reducing the discharge delay in ICU transfer

Adult↗
PubMed2006

Heel bone densitometry: device specific thresholds for the assessment of osteoporosis.

A diagnosis of osteoporosis is facilitated by bone mineral density (BMD) measurement of the lumbar spine and hip using dual energy X-ray absorptiometry (DXA), interpreted in accordance with criteria published by the World Health Organization (WHO). The use of peripheral DXA is growing in primary care and guidance on its use has recently been published by the National Osteoporosis Society (NOS), recommending a triage approach using thresholds specific to each type of peripheral device. However, no data currently exist for the Norland Apollo heel densitometer (Cooper Surgical, Trumbull, USA). 215 women between 50 years and 75 years of age (mean age 64.6 years) referred for hip and spine BMD measurements also had a heel BMD measurement. Device specific upper and lower thresholds were calculated for the Norland Apollo heel densitometer to give a 90% sensitivity and 90% specificity for osteoporosis at the hip or spine. Patients with a heel T-score of above -1.2 are very likely to have normal bone density on axial densitometry, whilst patients with heel T-score of below -2.2 are very likely to have osteoporosis at the hip or spine. Patients whose measurements lie between the thresholds should be referred for axial DXA.

Absorptiometry, Photon↗
PubMed2006

Influence of endogenous and exogenous orientations of attention on inhibition of return in a cross-modal target-target aiming task.

The authors conducted 2 experiments in which participants (N = 16 in each) executed successive unimanual aiming movements to target locations that were indicated by the onset of either an auditory or a visual stimulus. In Experiment 1 (exogenous orientation), inhibition of return (IOR) effects were observed, with reliable reaction time (RT) costs associated with movements returning to the same target and a trend toward larger IOR effects in left than in right space. There was no influence of stimulus modality on the magnitude of IOR. IOR was also observed in Experiment 2 (endogenous orientation), except the influence of stimulus modality reliably mediated those effect. In that case, IOR was evident only when the previous modality was visual and the current modality was auditory. Together, the results of those 2 experiments suggest that in situations in which 2 paired movements constitute the response criteria, IOR is both supramodal and lateralized to contralateral space.

Acoustic Stimulation↗
PubMed2005

Comparison of gait kinematics in patients receiving minimally invasive and traditional hip replacement surgery: a prospective blinded study.

Minimally invasive (MI) total hip replacement (THR) supposedly provides improved ambulation in the immediate post-operative period. This study used a prospective blinded design to analyse early post-operative walking ability using gait analysis. Seventeen patients were available for full analysis with nine having had the MI technique and eight having the standard incision (SI) technique. Patients were blinded as to the incision used, as were all physiotherapists and assessors. Differences in temporal-spatial variables and joint kinematics measured 1 day pre-operatively, 2 days post-operatively and 42 days (6 weeks) post-operatively were compared between groups. There was no significant difference in velocity, step length of the affected or unaffected leg, stride length or stance phase duration between the MI and SI groups between any of the timepoints tested. There was no significant improvement in the gait kinematics of the MI group compared to the SI group either 2 days post-operatively or 6 weeks post-operatively. Contrary to previous studies, there was no improvement in early post-operative gait for those patients who received THR using the minimally invasive technique.

Arthroplasty, Replacement, Hip↗
PubMed2004

Non-valvular atrial fibrillation and stroke: implications for nursing practice and therapeutics.

Atrial fibrillation (AF) is the most common sustained cardiac rhythm disturbance and is increasing in prevalence due to the ageing of the population, and rates of chronic heart failure. Haemodynamic compromise and thromboembolic events are responsible for significant morbidity and mortality in Australian communities. Non-valvular AF is a significant predictor for both a higher incidence of stroke and increased mortality. Stroke affects approximately 40,000 Australians every year and is Australia's third largest killer after cancer and heart disease. The burden of illness associated with AF, the potential to decrease the risk of stroke and other embolic events by thromboprophylaxis and the implications of this strategy for nursing care and patient education, determine AF as a critical element of nursing practice and research. A review of the literature was undertaken of the CINAHL, Medline, EMBASE and Cochrane Databases from 1966 until September 2002 focussing on management of atrial fibrillation to prevent thrombotic events. This review article presents key elements of this literature review and the implications for nursing practice.

Anti-Arrhythmia Agents↗
PubMed2004

Non-contact left ventricular endocardial mapping in cardiac resynchronisation therapy.

BACKGROUND: Up to 30% of patients with heart failure do not respond to cardiac resynchronisation therapy (CRT). This may reflect placement of the coronary sinus lead in regions of slow conduction despite optimal positioning on current criteria. OBJECTIVES: To characterise the effect of CRT on left ventricular activation using non-contact mapping and to examine the electrophysiological factors influencing optimal left ventricular lead placement. METHODS: and results: 10 patients implanted with biventricular pacemakers were studied. In six, the coronary sinus lead was found to be positioned in a region of slow conduction with an average conduction velocity of 0.4 m/s, v 1.8 m/s in normal regions (p < 0.02). Biventricular pacing with the left ventricle paced 32 ms before the right induced the optimal mean velocity time integral and timing for fusion of depolarisation wavefronts from the right and left ventricular pacing sites. Pacing outside regions of slow conduction decreased left ventricular activation time and increased cardiac output and dP/dt(max) significantly. CONCLUSIONS: In patients undergoing CRT for heart failure, non-contact mapping can identify regions of slow conduction. Significant haemodynamic improvements can occur when the site of left ventricular pacing is outside these slow conduction areas. Failure of CRT to produce clinical benefits may reflect left ventricular lead placement in regions of slow conduction which can be overcome by pacing in more normally activating regions.

Adult↗
PubMed2003

Influence of terminal action requirements on action-centered distractor effects.

Tipper (1985; Q J Exp Psychol A 37:571-590) has suggested that competing responses programmed to distracting stimuli are inhibited based on their relationship to the action being performed. The present paper reports two experiments designed to examine the influence of the terminal action of a task on the allocation of visual attention. Taken together the results suggest that when engaging targets in an environment, which includes distracting stimuli, competing responses are likely to be programmed in parallel and that the relationship between competing responses can include both spatial position and action characteristics.

Adult↗
PubMed2003

Prevalence of Csh-like fibrillar surface proteins among mitis group oral streptococci.

The prevalence of Csh-like fibrillar surface proteins among oral streptococci was investigated by ELISA and by immunoelectron microscopy using antiserum raised to recombinant fragments of CshA of Streptococcus gordonii DL1. The majority of S. gordonii, Streptococcus sanguis and Streptococcus oralis strains tested elaborated short (ca. 50-80 nm long) surface fibrils and reacted with antiserum to the amino acid repeat region of CshA, demonstrating the widespread nature of Csh-like proteins among these species. In contrast, reactivity with antiserum raised to the adhesion-mediating non-repetitive region of CshA was more restricted. On the basis of the ELISA results, several isolates were selected for immunogold analysis using CshA antisera. Immunogold-negative staining showed a surface distribution of 10 nm gold particles consistent with antibody binding to short fibrils. Long fibrils (>150 nm long), where present, were not significantly labelled with gold. The results suggest that some of the short peritrichous fibrils on many mitis group streptococci comprise Csh-like fibrillar protein. Further, the data are consistent with our hypothesis that the antigenically conserved amino acid repeat region of Csh-like proteins forms a scaffold for cell-distal presentation of the amino-terminal non-repetitive region that, at least in S. gordonii DL1, functions as an adhesin.

Adhesins, Bacterial↗
PubMed2003

Pathways of post-transcriptional gene regulation in mammalian germ cell development.

Male germ cell development is orchestrated by complex and disparate patterns of gene expression operating in different cell types. The mechanisms of gene expression underlying these have been dissected in the mouse because of its readily available genetics. These analyses have shown that as well as the traditional transcriptional mechanisms, post-transcriptional regulatory pathways of gene expression are essential for mouse spermatogenesis. Proteins essential for germ cell development have been identified which operate at different points throughout the life cycle of RNA from pre-mRNA splicing to translation and RNA decay in the cytoplasm. Recent data suggests that these post-transcriptional pathways respond to environmental cues via signalling pathways.

Animals↗
PubMed2003

Absence of mDazl produces a final block on germ cell development at meiosis.

The autosomal gene DAZL is a member of a family of genes (DAZL, DAZ, BOULE), all of which contain a consensus RNA binding domain and are expressed in germ cells. Adult male and female mice null for Dazl lack gametes. In order to define more precisely the developmental stages in germ cells that require Dazl expression, the patterns of germ cell loss in immature male and female wild-type (+/+, WT) and Dazl -/- (DazlKO) mice were analysed. In females, loss of germ cells occurred during fetal life and was coincident with progression of cells through meiotic prophase. In males, testes were recovered from WT and DazlKO males obtained before and during the first wave of spermatogenesis (days 2-19). Mitotically active germ cells were present up to and including day 19. Functional differentiation of spermatogonia associated with detection of c-kit positive cells did not depend upon expression of Dazl. RBMY-positive cells (A, intermediate, B spermatogonia, zygotene and preleptotene spermatocytes) were reduced in DazlKO compared with WT testes. Staining of cell squashes from day 19 testes with anti-gamma-H2AX and anti-SCP3 antibodies showed that germ cells from DazlKO males were unable to progress beyond the leptotene stage of meiotic prophase I. It was concluded that in the absence of Dazl, germ cells can complete mitosis, and embark on functional differentiation but that, in both sexes, progression through meiotic prophase requires this RNA binding protein.

Animals↗
PubMed2001

Malignant melanoma with a myxoid stroma: a diagnostic pitfall on fine-needle aspiration biopsy.

Malignant melanoma (MM), both primary and metastatic, may be associated with a prominent myxoid stromal reaction causing diagnostic confusion on fine-needle aspiration biopsy (FNAB), most often with sarcomas that demonstrate a myxoid stroma, particularly malignant peripheral nerve sheath tumor (MPNST). We present a case of a 32-yr-old man with no past medical history who presented with a unilateral neck mass clinically suspicious for lymphoma. FNAB produced a specimen composed of large sheets of anaplastic cells encased in a myxoid stroma that was S100 and vimentin-positive but HMB-45-negative. A diagnosis of MPNST was made. Excision demonstrated a metastatic MM of unknown primary, with a prominent myxoid stromal reaction. A repeat HMB-45 was again negative. Electron microscopy demonstrated intracytoplasmic melanasomes and cisternae of rough endoplasmic reticulum with intracisternal parallel tubules, confirming the diagnosis. Although HMB-45 is typically negative in both tumors, S100 should be strongly positive in myxoid MM and only focal in MPNST.

Adult↗
PubMed2001

Manual asymmetries in the preparation and control of goal-directed movements.

The primary purpose of this experiment was to determine if left hand reaction time advantages in manual aiming result from a right hemisphere attentional advantage or an early right hemisphere role in movement preparation. Right-handed participants were required to either make rapid goal-directed movements to small targets or simply lift their hand upon target illumination. The amount of advance information about the target for a particular trial was manipulated by precuing a subset of potential targets prior to the reaction time interval. When participants were required to make aiming movements to targets in left space, the left hand enjoyed a reaction advantage that was not present for aiming in right space or simple finger lifts. This advantage was independent of the amount or type of advance information provided by the precue. This finding supports the movement planning hypothesis. With respect to movement execution, participants completed their aiming movements more quickly when aiming with their right hand, particularly in right space. This right hand advantage in right space was due to the time required to decelerate the movement and to make feedback-based adjustments late in the movement trajectory.

Adult↗
PubMed2001

Gender differences in a dichotic listening and movement task: lateralization or strategy?

Although the dichotic listening procedure has been used as a non-invasive neuropsychological technique for assessing laterality of speech perception, it has tended to underestimate the proportion of the right-handed population that is left-hemisphere lateralized for speech perception [Segalowitz SJ, Bryden MP. Individual differences in hemispheric representation of language. In: Segalowitz SJ (Ed.), Language Functions and Brain Organization. Toronto: Academic Press, 1983, pp. 341-72]. These underestimations may be due to traditional dichotic procedures being susceptible to attentional biases, order of report effects, and/or memory effects that obscure functional differences between the cerebral hemispheres. In the present study, we used an adaptation of the dichotic listening procedure that was designed to be less sensitive to these confounding effects. Participants were required to move as quickly as possible to one of the two color-coded targets following verbal cues presented via headphones. Conditions of cue-word presentation were monaural, (e.g. 'blue' in one ear and a blank track in the other), dichotic-same (e.g. 'blue' in both ears), and dichotic-different (e.g. 'green' in one ear and 'blue' in the other). Ninety-three percent (26 of 28) of the participants demonstrated a right ear advantage (REA) for correct responses. There was also a REA for reaction time, movement time, and the total response time. The pattern of reaction time and movement errors, however, suggest that gender differences found utilizing this dichotic procedure may be due to differences in strategic approach to the task rather than to differences in cerebral laterality. Overall, results suggest that this new adaptation of the dichotic listening procedure is very sensitive to lateralization for speech perception.

Adult↗
PubMed2001

Eye-hand coordination in goal-directed aiming.

In a number of studies, we have demonstrated that the spatial-temporal coupling of eye and hand movements is optimal for the pickup of visual information about the position of the hand and the target late in the hand's trajectory. Several experiments designed to examine temporal coupling have shown that the eyes arrive at the target area concurrently with the hand achieving peak acceleration. Between the time the hand reached peak velocity and the end of the movement, increased variability in the position of the shoulder and the elbow was accompanied by a decreased spatial variability in the hand. Presumably, this reduction in variability was due to the use of retinal and extra-retinal information about the relative positions of the eye, hand and target. However, the hand does not appear to be a slave to the eye. For example, we have been able to decouple eye movements and hand movements using Müller-Lyer configurations as targets. Predictable bias, found in primary and corrective saccadic eye movements, was not found for hand movements, if on-line visual information about the target was available during aiming. That is, the hand remained accurate even when the eye had a tendency to undershoot or overshoot the target position. However, biases of the hand were evident, at least in the initial portion of an aiming movement, when vision of the target was removed and vision of the hand remained. These findings accent the versatility of human motor control and have implications for current models of visual processing and limb control.

Adult↗
PubMed2001

The one-target advantage: a test of the movement integration hypothesis.

Two experiments were conducted to compare the temporal structure of single aiming movements to two-component movements involving either a reversal in direction or an extension. For reversal movements, there was no cost associated with the movement time for the first segment of the movement. However, regardless of movement direction, initiation instructions, handedness or effector, two-component extension movements were always associated with a longer movement time for the first movement segment. This disadvantage for extension movements, but not reversal movements, is consistent with the notion that there is interference between the execution of the first movement and implementation of the second movement. By contrast, because the muscular force used to break the first movement is also used to propel the second movement, reversal movements are organised as an integrated unit.

Adolescent↗
PubMed2001

The utilization of visual information in the control of reciprocal aiming movements.

Two experiments examined on-line processing during the execution of reciprocal aiming movements. In Experiment 1, participants used a stylus to make movements between two targets of equal size. Three vision conditions were used: full vision, vision during flight and vision only on contact with the target. Participants had significantly longer movement times and spent more time in contact with the targets when vision was available only on contact with the target. Additionally, the proportion of time to peak velocity revealed that movement trajectories became more symmetric when vision was not available during flight. The data indicate that participants used vision not only to 'home-in' on the current target, but also to prepare subsequent movements. In Experiment 2, liquid crystal goggles provided a single visual sample every 40 ms of a 500 ms duty cycle. Of interest was how participants timed their reciprocal aiming to take advantage of these brief visual samples. Although across participants no particular portion of the movement trajectory was favored, individual performers did time their movements consistently with the onset and offset of vision. Once again, performance and kinematic data indicated that movement segments were not independent of each other.

Adolescent↗