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Biomedical subjects

E Hart

Publications and source records attributed to E Hart.

At least 19 recordsLinked to original sources
PubMed1999

Computed radiography dual energy subtraction: performance evaluation when detecting low-contrast lung nodules in an anthropomorphic phantom.

A dedicated chest computed radiography (CR) system has an option of energy subtraction (ES) acquisition. Two imaging plates, rather than one, are separated by a copper filter to give a high-energy and low-energy image. This study compares the diagnostic accuracy of conventional computed radiography to that of ES obtained with two radiographic techniques. One soft tissue only image was obtained at the conventional CR technique (s = 254) and the second was obtained at twice the radiation exposure (s = 131) to reduce noise. An anthropomorphic phantom with superimposed low-contrast lung nodules was imaged 53 times for each radiographic technique. Fifteen images had no nodules; 38 images had a total of 90 nodules placed on the phantom. Three chest radiologists read the three sets of images in a receiver operating characteristic (ROC) study. Significant differences in Az were only found between (1) the higher exposure energy subtracted images and the conventional dose energy subtracted images (P = .095, 90% confidence), and (2) the conventional CR and the energy subtracted image obtained at the same technique (P = .024, 98% confidence). As a result of this study, energy subtracted images cannot be substituted for conventional CR images when detecting low-contrast nodules, even when twice the exposure is used to obtain them.

Analysis of Variance↗
PubMed1999

CT-guided catheter drainage of loculated thoracic air collections in mechanically ventilated patients with acute respiratory distress syndrome.

OBJECTIVE: We report our experience with CT-guided percutaneous catheter drainage of loculated thoracic air collections in mechanically ventilated patients with acute lung injury or acute respiratory distress syndrome. MATERIALS AND METHODS: Nine critically ill patients had 17 air collections (13 pneumothoraces, three pneumatoceles, one tension pneumomediastinum) that either developed despite the presence of standard surgical chest tubes or were in loculated sites that were difficult to access. All nine patients were ventilated mechanically for a clinical diagnosis of acute respiratory distress syndrome. Catheter size ranged from 7- to 28-French. Response was measured by imaging follow-up, ventilatory parameters, and clinical outcome. RESULTS: On follow-up imaging studies, all 17 air collections were shown to have been evacuated successfully. Catheters remained in place for a mean of 11 days (range, 4-28 days). No major complications occurred. Sixteen air collections were treated successfully with CT-guided catheter placement alone; the remaining air collection, a pneumothorax, was treated with subsequent placement of a chest tube by the surgeon at the patient's bedside. No surgery was undertaken for the air collections. Improvement in gas exchange was documented by increase in the hypoxemia ratio (arterial oxygen pressure divided by the inspired fraction of oxygen) in seven of 12 drainages; the other drainages were accompanied either by no improvement or by deterioration. Eight (89%) of the nine patients eventually were extubated and discharged from the hospital. The ninth patient died. CONCLUSION: CT-guided percutaneous catheter drainage provided effective treatment for loculated thoracic air collections and obviated surgical intervention in these critically ill, high-surgical-risk patients.

Adult↗
PubMed1998

Evaluating a pilot community stroke service using insights from medical anthropology.

This paper focuses on the evaluation of a pilot community stroke service. Its aim is to illustrate how the insights gained from the research of two medical anthropologists, Kaufman and Pinder, provided an understanding of the experience of chronic illness in the community. Two linked themes identified in the literature, which also emerged from the exploratory phase of the evaluation, are discussed: the tension between the patient's goal of recovery and the professional's goal of rehabilitation; and the management of uncertainty. It is argued that it may be very difficult, if not impossible, to reconcile these divergent goals of recovery and rehabilitation, and that this problem is exacerbated for patients and professionals alike by the challenge of how to manage the uncertainty of a chronic illness such as stroke. The empirical findings of the first phase evaluation corroborate Kaufman and Pinder's findings. Furthermore, the present research suggests that the mismatch between the goals of recovery and rehabilitation, and the management of uncertainty are integrally related. The implications for practice are that there is a need for professionals to find ways of recognizing and taking account of the possible tensions between their goals and those of patients and families, and related to this, for the development of strategies which enable professionals to explain clearly the nature of stroke to patients and their carers.

Anthropology, Cultural↗
PubMed1998

Solving a real-world problem using an evolving heuristically driven schedule builder.

This work addresses the real-life scheduling problem of a Scottish company that must produce daily schedules for the catching and transportation of large numbers of live chickens. The problem is complex and highly constrained. We show that it can be successfully solved by division into two subproblems and solving each using a separate genetic algorithm (GA). We address the problem of whether this produces locally optimal solutions and how to overcome this. We extend the traditional approach of evolving a "permutation + schedule builder" by concentrating on evolving the schedule builder itself. This results in a unique schedule builder being built for each daily scheduling problem, each individually tailored to deal with the particular features of that problem. This results in a robust, fast, and flexible system that can cope with most of the circumstances imaginable at the factory. We also compare the performance of a GA approach to several other evolutionary methods and show that population-based methods are superior to both hill-climbing and simulated annealing in the quality of solutions produced. Population-based methods also have the distinct advantage of producing multiple, equally fit solutions, which is of particular importance when considering the practical aspects of the problem.

Algorithms↗
PubMed1998

Analytical decision model for the cost-effective management of solitary pulmonary nodules.

PURPOSE AND METHODS: Multiple strategies are currently being used to manage patients who present with indeterminate solitary pulmonary nodules (SPN). We have used decision-analysis models to assess the cost-effectiveness of various strategies for the diagnosis and management of SPN. Four decision strategies were compared: a wait and watch strategy, a surgery strategy, a computed tomography (CT)-based strategy, and a CT-plus-positron emission tomography (PET) strategy. An incremental cost-effectiveness ratio (ICER) was used to compare all strategies to the wait and watch strategy. RESULTS: A CT-plus-PET strategy was the most cost-effective over a large pretest likelihood (probability of having a malignant nodule), with a range of 0.12 to 0.69. Furthermore, within this likelihood range, the potential cost savings of using the CT-plus-PET strategy over the CT strategy ranged from $91 to $2,200 per patient. This translates to a yearly national savings of approximately $62.7 million. CONCLUSION: Decision-analysis modeling indicates the potential cost-effectiveness of [18F]2-fluoro-2-deoxy-D-glucose (FDG)-PET in the management of SPN. Furthermore, the decision trees developed can be used to model various features of the management of SPN, including modeling the cost-effectiveness of other newly emerging technologies.

Adult↗
PubMed1996

Action research as a professionalizing strategy: issues and dilemmas.

This paper identifies the need for a debate about the appropriateness of action research for nursing as it seeks to achieve the status of a research-based profession. It also identifies a related need to inform such a debate by bringing together three sets of writings that are not normally united in the nursing research literature-those of action research, organizational culture and professionalization. In nursing, as in education, action research is being deployed as part of a professionalizing strategy, since amongst other things it seems to offer a means of developing reflective practitioners and of producing knowledge for practice. The increasing popularity of action research amongst nurse researchers suggests that it is seen to reflect the attributes to which nursing aspires as a profession, including a concern to realize humanistic values. Action research was embraced by the teaching profession before nursing, and nurse researchers are increasingly drawing on the ideas of influential educationalists in defining action research as an emancipatory strategy and a form of collaborative enquiry rooted in reflective practice. This paper argues that in the managerialist context of the British National Health Service action research may be reduced from a participatory methodology into a method for getting people to collaborate with managerial goals and internalize the values of the corporate culture. The danger is that in the name of reflective practice nursing work may become increasingly individualized. The challenge for action research in nursing is how to respond to this dilemma, and this may require looking critically at the managerial values underpinning the NHS reforms and at the organizational context in which action research strategies are deployed.

Education↗
PubMed1996

Making sense of action research through the use of a typology.

Commenting on earlier work in the Journal of Advanced Nursing on action research, this paper takes up the theme of definition and approach and presents an original action research typology. Three key criteria of action research--'reeducation', 'problem focus', and 'improvement and involvement'--are related to four broad types of action research: 'experimental', 'organizational', 'professionalizing' and 'empowering'. The typology is of general relevance not only to action researchers but to any project concerned to resolve problems and bring about improvements in practice, including evaluation research. Following discussion of the typology, it is used to analyse three different action research projects, including one conducted by the authors in collaboration with a project team. It is shown that each of these projects, which are all concerned in some way to improve standards of nursing care in hospitals, contains elements of different types which may at times be in conflict. The ability to recognize this and to be explicit about the different types may assist action researchers in selecting an appropriate approach and in anticipating problems which may arise during the course of a project's life.

Health Services Research↗
PubMed1995

Induction of antigen-specific T and B cell immunity in colon carcinoma patients by anti-idiotypic antibody.

Polyclonal goat anti-idiotypic Abs directed against anti-human gastrointestinal carcinoma mAb GA733 were administered to 13 colon cancer patients who had their primary tumor and lymph node metastases removed before immunotherapy. Patients received four s.c. doses (0.5 to 8 mg each) of alum-precipitated anti-idiotypic Ab. Seven of the 13 patients produced anti-anti-Ids that bound specifically to the GA733 epitope on tumor cells and shared idiotopes with mAb GA733. In four of the seven responding patients, anti-Id therapy specifically modulated T cell responses. In two patients who did not demonstrate GA733 Ag/anti-Id-reactive T cells before therapy, anti-Id administration induced CD4+, MHC class II-dependent T cells that specifically proliferated in culture in response to stimulation with either anti-Id or GA733 Ag. In two other patients who did demonstrate Ag/anti-Id-reactive T cells before therapy, anti-Id administration transiently induced lymphocytes that suppressed the proliferative responses of cultured pretherapy lymphocytes to stimulation with anti-Id or GA733 Ag. Nine of the 13 treated patients showed no evidence of disease after 39 to 86 mo of observation. Five of these patients developed Ag-specific Ab3 and one had, in addition, a T cell response.

Adult↗
PubMed1995

Research challenges: issues in the management of research projects.

Earlier work published in this journal has highlighted problems in the management of nursing research, including tensions between nurse managers and researchers. Building on this earlier work the challenges posed by research in the volatile organizational context of the British National Health Service (NHS) are discussed in relation to two areas: the early stages of establishing a research project, and defining the roles and responsibilities of those involved in the research. It is argued that many of the problems which hinder the successful completion of research can be traced back to the early stages of establishing the project, including a lack of clarity about its aims, purpose and objectives. Such problems are compounded by the lack of attention given to the task of defining the respective roles and responsibilities of manager and researcher, as well as of others in a research team. It is concluded that one of the major tasks for research and development in the current climate of the NHS is to find ways of dealing with such challenges which promote increased understanding between manager and researcher. Ways in which this might be achieved are suggested.

Conflict, Psychological↗
PubMed1994

Immunomodulatory activity of monoclonal anti-idiotypic antibody to anti-colorectal carcinoma antibody CO17-1A in animals and patients.

Monoclonal anti-idiotypic antibody (Ab2) VF2 was derived from rats immunized with anti-colorectal carcinoma (anti-CRC) monoclonal antibody (Ab1) CO17-1A. In rabbits the Ab2 induced anti anti-idiotypic antibodies (Ab3) that shared idiotopes with the Ab1, bound to the same epitope on CRC cells as Ab1, and bound to the isolated CO17-1A antigen. Monoclonal Ab2 VF2 was superior to the previously described polyclonal goat Ab2 against Ab1 CO17-1A in its capacity to elicit humoral immunity in animals. Ab2 VF2 also induced a specific delayed-type hypersensitivity (DTH) response to challenge with irradiated CO17-1A antigen-positive human CRC cells in mice. Of nine CRC patients immunized with aluminum hydroxide-precipitated Ab2 VF2, six developed antibodies that bound to Ab2, but only three patients developed Ab3 that bound to idiotypic determinants on Ab2. However, the Ab3 did not bind to CO17-1A antigen-positive CRC cells. In contrast, in a previously described trial with polyclonal goat Ab2 to Ab1 CO17-1A, most of the patients developed anti-CRC antibodies. Four of the nine patients immunized with Ab2 VF2 developed DTH responses to intradermal challenge with the Ab2, and in one patient DTH was both Ab2- and antigen-specific. Peripheral blood mononu-clear cells of the four DTH-reactive patients did not proliferate in response to in vitro stimulation with either Ab2 or antigen. These studies demonstrate that the immunomodulatory activity of monoclonal Ab2 VF2 in animals is only in part predictive of its activity in patients.

Animals↗
PubMed1991

Ghost in the machine.

Management insistence that nursing must be reduced to measurable tasks is undermining the intuitive and creative essence of the profession and removing it from its wider context, says Elizabeth Hart.

Clinical Competence↗
PubMed1990

Relationship of professional involvement to clinical behaviors of physical therapists.

This study was designed to measure the level of professional involvement of respondents and to examine the relationship between a high level of professional involvement (eg, membership in the American Physical Therapy Association, attendance at Association conferences, participation in continuing education programs) and the frequency of use of high-complexity procedures. A questionnaire survey of 165 Alabama physical therapists was conducted to establish 1) the ranking of 24 physical therapy procedures according to the perceived level of complexity and 2) the relationship of a procedure's rank to delegation of that procedure to support personnel. The ranking and a cluster analysis of the 24 procedures correlated with similar ranking in other studies (Pearson r = .92). The level of complexity of a procedure influenced delegation to support personnel, with high-complexity procedures being delegated less frequently and requiring greater supervision than moderate- and low-complexity procedures. There was variation in the frequency of use of procedures, but a clear relationship was not found between a high level of professional involvement and use of high-complexity procedures. A relationship existed between professional involvement and both job title and types of referrals received. Those physical therapists with a higher level of professional involvement tended to be directors and supervisors (chi 2 = 28.29, df = 2, p less than .001), and they received autonomous referrals with greater frequency than those physical therapists with a lower level of involvement (chi 2 = 16.25, df = 3, p less than .001). The findings have implications for the continued professionalization of physical therapy and for the role that physical therapy educators and administrators play in this process.

Administrative Personnel↗
PubMed1985

Selective control of human glioma cell proliferation by specific cell interaction.

Cells cultured from anaplastic astrocytoma (Kernohan and Sayre, grades III and IV) will proliferate on confluent monolayers of normal glia, while cells cultured from normal brain will not. The growth of a cell line containing a high proportion of well-differentiated glioma cells (G-CCM) was partially inhibited, though not as much as normal glia, while the growth of a cell line made up of less differentiated cells (G-UVW) was enhanced by the normal glia. Although non-glial confluent monolayers also inhibited the growth of normal glia, this was less specific, as one normal glial line (N-DUT) grew on fibroblasts and intestinal epithelium, although it was unable to do so on normal glia. It is suggested that this may be a useful method for examining reduced density limitation of growth, discriminating between normal and malignant glia, and for separating glioma cells from contaminating normal cells.

Cell Communication↗