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Biomedical subjects

D White

Publications and source records attributed to D White.

At least 199 records · Page 11Linked to original sources
PubMed1992

(De)-constructing continuity of care: the deinstitutionalization of support services for people with mental health problems.

The objective of this paper is to raise questions about appropriateness of the concept of continuity of care for guiding the development of helping strategies for people with mental health problems in the era of noninstitutionalization. Research on continuity of care is reviewed to show the strong legacy of institutional thinking. A leading problem addressed in this literature is that of client drop-out from programs designed to ensure continuity. The research results clearly suggest that this "problem" lies with the agency of clients: the fact that, in the natural milieu, they make decisions according to their own definitions of the situation and in a social context of their own. This perspective, however, seemingly cannot be incorporated into the continuity of care paradigm, which remains firmly grounded in the world of service providers. We argue, therefore, that the era of the noninstitutionalization calls for a recasting of the meaning of "continuity" for people with mental health problems, a reorientation of the type of research conducted in this domaine, and ultimately, a reformulation of the nature and role of support services in the community.

Community Mental Health Services↗
PubMed1991

Functional and ultrastructural effects of a missense mutation in the indirect flight muscle-specific actin gene of Drosophila melanogaster.

A single-site mutation of the flight-muscle-specific actin gene of Drosophila melanogaster causes a substitution of glutamic acid 93 by lysine in all the actin encoded in the indirect flight muscle (IFM). In these Act88FE93K mutants, myofibrillar bundles of thick and thin filaments are present but lack Z-discs and all sarcomeric repeats. Dense filament bundles, which are probably aberrant Z-discs, are seen in myofibrils of pupal flies, but early in adult life these move to the periphery of the fibrils and are not seen in skinned adult fibres. Consistent with this observation, alpha-actinin and other high molecular weight proteins, possibly associated with Z-discs, are not detected on SDS/polyacrylamide gels or Western blots of skinned adult IFM. The mutation lies at the beginning of a loop in the small domain of actin, near the myosin binding region. However, that the mutant actin binds myosin heads is shown by (1) rigor crossbridges in electron micrographs, (2) the appropriate rise in stiffness when ATP is withdrawn in mechanical experiments, and (3) equal protection against tryptic digestion provided by rigor binding between actin and myosin in both wild-type and mutant fibres. Reversal of rigor chevron angle along some thin filaments reflects reversal of thin-filament polarity due to lattice disorder. The absence of Z-discs, alpha-actinin and two high molecular weight proteins, and binding studies by others, suggest that the substitution at residue 93 affects the binding of the mutant actin to a protein, possibly alpha-actinin, which is necessary for Z-disc assembly or maintenance.

Actins↗
PubMed1991

The magnetic properties of some materials affecting MR images.

We have compared the magnetic properties of various types of materials known to affect MR images. The materials compared were: (i) MR contrast agents based on chelates of paramagnetic metals (Gd-DTPA, Dy-DTPA); (ii) biological forms of iron (horse spleen ferritin and deoxyhemoglobin); and (iii) a superparamagnetic iron oxide (AMI-25). The properties compared were the magnetic susceptibility and the magnetization. The magnetization and susceptibility of superparamagnetic AMI-25 are far larger than that of ferritin or low molecular weight, paramagnetic chelates. Superparamagnetic iron oxide colloids, like AMI-25, are a uniquely powerful class of magnetic materials.

Animals↗
PubMed1991

CGS 22745: a selective orally active inhibitor of 5-lipoxygenase.

CGS 22745, and aralkyl hydroxamic acid, inhibited 5-hydroxyeicosatetraenoic acid (5-HETE) and leukotriene B4 (LTB4) synthesis in guinea pig leukocytes (IC50 = 0.6 microM). The compound did not appreciably affect cyclooxygenase (ram seminal vesicles), 12-lipoxygenase and thromboxane synthase (human platelets) or 15-lipoxygenase (human neutrophils). CGS 22745 inhibited A23187-induced formation of LTB4 in blood (IC50's of 4.3, 0.56 and 3.2 microM for human, dog and rat, respectively). At 1 mg/kg i.v. in dogs, it caused 96% inhibition of A23187-stimulated LTB4 formation ex vivo after 5 min. Its effective biological half-life was greater than 160 min. In dogs at 3 and 10 mg/kg p.o., CGS 22745 inhibited ex vivo A23187-stimulated LTB4 formation at 3 hr by 48% and 97%, respectively. The inhibition persisted up to 6 hr (26% at 3 mg/kg; 49% at 10 mg/kg). CGS 22745 (3, 10 and 30 mg/kg p.o.) inhibited exudate formation, mononuclear cells and PMN accumulation in a dose-dependent manner during the late phase (48 and 72 hr) of carrageenan-induced pleurisy in the rat.

Administration, Oral↗
PubMed1991

Histologic, immunophenotypic and genotypic analyses of bone marrow trephines from patients with non-Hodgkin's lymphoma.

Marrow involvement in 20 patients with non-Hodgkin's lymphoma (NHL) were studied by histology, immunophenotypic and genotypic methods. Eighteen of these trephines were histologically involved with recognizable lymphomatous infiltrates and five of these were the primary disease site. In the remaining two cases (with histologically involved lymph nodes) the trephines were uninvolved with tumour. Three B-cell cases expressing surface immunoglobulin (sIg) and/or CD37 and one case not analysed phenotypically showed Ig gene rearrangements. The two remaining cases with B NHL showed no gene rearrangements, however, in one of these the trephine was histologically uninvolved with tumour. Twelve out of 14 T-cell cases were characterized by variable or absent expression of one or more T-cell antigens from the tumour population, one case was negative for all T-cell antigens and the remaining case was not histologically involved with tumour. All three lymphoblastic lymphomas and only 4/11 peripheral T-cell lymphomas (PTCL) cases revealed T-cell receptor (TcR) gene rearrangements. One of the latter cases also exhibited Ig JH gene rearrangements. This study demonstrates the usefulness of bone marrow trephines (BMT) in histologic, phenotypic and genotypic analyses. However, although genotypic data confirm clonality in B NHL and the lymphoblastic lymphomas there was genotypic heterogeneity within the PTCL group.

Antigens, CD↗
PubMed1991

Registered nurse stress in intensive care units--an Australian perspective.

This paper describes a study of stressors and coping mechanisms in different grades of registered nurses in Intensive Care Units (ICUs). The research demonstrated that significant correlation existed between relating what and when to report clinical patient changes and relating theory to practice. Significant differences existed between groups with regard to the stress associated with caring for acutely ill patients, role conflict with medical staff and relationships with senior medical and nursing staff. The findings confirm that environmental stressors are the major stressors in ICU and demonstrate that sound knowledge and clinical assessment skills are important factors in reducing perceived stress, thus supporting the continued need for competency and skills focused post registration courses and in-service education.

Adaptation, Psychological↗
PubMed1991

Coordinating community and public-institutional mental health services: some unintended consequences.

Where a target group such as the mentally ill tend to use multiple and varied services over a long period of time, service coordination is often seen as the key to continuity of care. This article argues that coordination also has its perverse effects. To demonstrate, two types of community organizations (COs) working in mental health in the Canadian province of Québec are examined: alternative COs, which have their roots in community action and maintain few formal links with each other or with institutional resources; and transitional structures, COs which are developed with the cooperation of psychiatric professionals, are closely linked to hospitals and are often part of a tightly coordinated system of community services. With respect to access, continuity, programs, internal structure and flexibility, each type of community resource has particular strengths and weaknesses. In the first part of the article, these are described and compared. In the second part of the article, we examine the possible effects of Québec's new mental health policy on COs working in mental health. The policy seeks to create comprehensive systems coordinating all services at the regional level-including alternative organizations, transitional structures and public institutions. The imperatives of the complex planning process risk diluting or even eradicating the differences between the two types of mental health COs described earlier. The process may thus rob certain service users of the particular advantages they found in alternative COs. For those mentally ill who, by choice or by chance, remain marginal to the coordinated system, there may ultimately be no resources available at all.

Community Mental Health Services↗
PubMed1991

Induction of long-term survival of hamster heart xenografts in rats.

The aim of this study was to determine the mechanisms responsible for concordant xenograft rejection using the hamster-to-rat heart graft model. Even though it was known that rat CD4 positive T cells proliferated to hamster stimulators in mixed lymphocyte reactions, the depletion of CD4 positive T cells in rat recipients did not lead to an extension of xenograft survival. Suppression of T cell immunity using other monoclonal antibodies or cyclosporine also failed to improve survival. Only by depleting complement with cobra-venom factor could hamster xenograft survival be prolonged, and long-term survival was achieved by combining CsA with COF. High-antibody titers to hamster cells were found after transplantation of hamster hearts, and evidence is presented that rejection of these "concordant" xenografts is mediated primarily by antibody-complement mechanisms. The antihamster antibodies were produced in the absence of T cell help, which suggests that antibody-mediated graft destruction cannot be inhibited by suppression or depletion of T cells. Pharmacologic depletion of complement for the clinical application of concordant xenografts is a promising avenue of future research.

Animals↗
PubMed1991

Protein engineering and the study of muscle contraction in Drosophila flight muscles.

We describe an experimental approach to the use of genetics to study muscle contraction in Drosophila melanogaster. Mutations induced by in vitro mutagenesis are inserted into the genome of flies using P-element mediated transformation, permitting the effects of the mutant genes to be studied in vivo in the indirect flight muscles (IFMs). Details of how mechanical experiments can be performed on skinned IFMs, despite their small size, are provided. The effects of two in vitro actin mutations, G368E and E316K, are described. The problems of performing biochemical and biophysical experiments on the IFMs and their myofibrillar proteins are described, together with indications as to how these may be overcome.

Actins↗
PubMed1991

Consensus management as a pattern of care within a general surgical ward.

This paper describes changes in the pattern of care delivery in a general surgical ward. The results reported are from the pilot study which was designed to establish that a model other than the team leader model was possible within this setting. Data was collected from staff regarding their perceptions of the changes and also from patients regarding their perceptions of the quality of their care. The research showed that a patient centred, consensus management pattern of care was the preferred choice by staff. Patient opinion surveys and staff evaluations supported the greater continuity in care of the patients in the trial group as compared to the control group. Initial nursing assessment and planning of nursing care were significantly better (p greater than 0.05) within the trial group as compared to the control group when measured utilising a standardised quality assurance tool.

Hospital Units↗
PubMed1991

Is choice of catheter size an important factor in patient discomfort?

This paper describes a study which was undertaken in order to assess nurses' knowledge regarding catheter size and determine whether the size of the catheter chosen related to patient discomfort. The results presented are those of the pilot study. The knowledge level of nurses regarding criteria for selection of catheter size was variable and demonstrated deficits reported by other studies. The patients included in the sample (n = 23) did not experience significant discomfort, leaking or pain as a result of catheter size which varied from 14-2Ch.

Catheters, Indwelling↗
PubMed1991

Influenza vaccination: is it worth it?

Australian government policy is to offer influenza vaccine every autumn to all Australians over the age of 65 and to those of any age who suffer from any chronic condition that predisposes to serious complications following influenza. Despite this clear advice from NHMRC and the financial incentives provided by Medicare and the PBS, less than one in three of this vulnerable cohort receives the vaccine. In this article the medical profession is exhorted to encourage and facilitate influenza vaccine delivery to the old and to the frail.

Australia↗