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Biomedical subjects

B McCormack

Publications and source records attributed to B McCormack.

At least 19 recordsLinked to original sources
PubMed1998

Femoral cementing techniques in total hip replacement.

Clinical studies have shown that second-generation femoral cementing techniques at total hip replacement result in a superior fixation of the femoral stem. In an effort to determine what benefits further developments in cementing techniques would provide, we compared the morphology of the cement mantles produced by traditional finger-packing and gun-insertion techniques. The porosity of the cement mantles was quantified using computerised image analysis. The finger-packing technique caused large air inclusions that resulted in large pores in the substance of the cement mantle, whereas the cement-gun technique did not result in any individual pore with an equivalent diameter greater than 3 mm. The mean porosity of cement mantles prepared using the finger-insertion technique was 8.3%, whereas the mean porosity in gun-prepared mantles was 1.7%. The use of a cement gun significantly reduced the porosity of femoral cement mantles (P = 0.02). Reduction of defects in the substance of the cement mantle may account for the increased survival of femoral prostheses inserted when second-generation techniques were used. Further reduction of the porosity of the cement mantle could not be expected to produce as dramatic a clinical improvement in prosthesis fixation.

Arthroplasty, Replacement, Hip↗
PubMed1998

Using a supervisory framework to support and evaluate a multiproject practice development programme.

The paper describes a multiproject practice development programme undertaken over a period of 1 year. The background and development of the programme are outlined, whilst attention is paid to the innovatory nature of the work, particularly the use of inductive, deductive and integrated approaches to both change implementation and project supervision. The programme was monitored throughout using different data sources and the paper uses evaluative material retrospectively to provide answers to organizational and professional difficulties which arose during the course of the programme. The authors conclude that the use of combinations of different models for practice development has potential, but requires careful supervision. They also recommend that those involved in practice development are made fully aware of its local or micropolitics, and develop strategies to deal with change before it occurs, not after it has taken place.

Evidence-Based Medicine↗
PubMed1998

Build consensus and develop collaborative practice guidelines.

With differing treatment guidelines available from many sources, collaborating advanced practice nurses and physicians at this facility recognized the need for one clear, acceptable set. Survey results show that clinicians incorporate all or most of the guidelines into practice (91%).

Ambulatory Care↗
PubMed1996

Comparative studies of the fate of free and liposome-entrapped hydroxypropyl-beta-cyclodextrin/drug complexes after intravenous injection into rats: implications in drug delivery.

Inclusion complexes of 14C-labelled hydroxypropyl-beta-cyclodextrin (HP beta-CD) with tritiated dehydroepiandrosterone (DHEA), retinol (RET) and dexamethasone (DEX) were entrapped in the aqueous phase of liposomes composed of distearoyl phosphatidylcholine. Incubation of liposome-entrapped complexes in the presence of rat blood plasma at 37 degrees C resulted in complex dissociation and drug leakage in the media at a rate which was minimal for DEX/HP beta-CD (11%), modest for RET/HP beta-CD (23%) and considerable for DHEA/HP beta-CD (56%; 60 min). In contrast, the HP beta-CD moiety of the complexes was retained by liposomes quantitatively. Free complexes injected intravenously into rats were cleared rapidly from the circulation with most (up to 94%) of the HP beta-CD moiety recovered in 24 urine together with lesser and variable amounts of drug (up to 46% of the dose) in a pattern (DHEA < RET < DEX) that was consistent with the extent of drug association with HP beta-CD in the presence of plasma. A significant proportion of the drugs (up to 25% of the dose)(but very little HP beta-CD) was removed by the liver where drugs were catabolised rapidly, probably following complex dissociation and transport to the tissue via plasma proteins. Injection of entrapped complexes revealed that liposomes alter their pharmacokinetics with only 6-13% of HP beta-CD and a moderate proportion of drugs (up to 26% of the dose) recovered in the urine. Much of the HP beta-CD moiety of the liposomal complexes was recovered in the liver (up to 83%) and spleen (up to 13% of the dose) by 30 min after injection, together with a variable proportion of drugs in a pattern (DHEA < RET < DEX) which reflected that of complex dissociation in vitro. Longer term experiments where animals injected with liposome-entrapped complexes were killed at time intervals (up to 24 days), revealed that HP beta-CD is eliminated from the tissues, albeit at a very slow rate. Moreover, the metabolism of individual drugs in the tissues following vesicle disintegration, appeared to depend on the rate of complex dissociation with DEX, for instance, reaching values of 4-6% (liver) only after 14 days. It is concluded that administration of drug/cyclodextrin inclusion complexes via liposomes could serve as a means to control the action of a wide range of therapeutic agents.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1996

Developing outcome indicators in continuing care: part 2.

In their follow-up to last week's article which described the development of outcome indicators for nursing older people in continuing care settings, the authors describe in detail the process of indicator development. Referring to theoretical models, they provide a practical example of how a nurse could use one of his or her experiences from nursing to illustrate the distinct value of patient interventions provided by a registered practitioner.

Aged↗
PubMed1996

Developing outcome indicators in continuing care: part 1.

In the first of two articles, the authors describe the development of outcome measures for nursing older people in a continuing care setting. They describe why such a process was initiated and the framework which guided the project, including current nursing and government policy and theories of knowledge and expert practice. The second article will appear next week.

Accidental Falls↗
PubMed1995

The development of clinical leadership through supported reflective practice.

The notion of clinical leadership is significant in current nursing practice, particularly since recommendations made by the Department of Health in 'The Strategy for Nursing'. However, while it is a concept that many nurses aspire to implement, in reality the operationalizing of such a concept is fraught with difficulty. This paper aims to explore the issue of clinical leadership through a collegiate model developed in a particular practice area. The development of this collegiate relationship is articulated through the mediums of reflective practice and clinical supervision. A model of collegiality is offered as an approach to the integration of the spheres of clinical leadership. If reflective practice is to be a reality then it is essential that both clinical leaders and practitioners engage in such processes within a supportive culture.

Clinical Competence↗
PubMed1995

Latex sensitivity: an occupational health strategic plan.

1. Health care workers, due to ongoing exposure to latex products, may be at risk of developing latex sensitivity. 2. The spectrum of reactions related to medical glove use varies in severity. Awareness of latex sensitivity is heightened through worker education. 3. Guidelines and interventions for occupational health nurses are outlined so that workers who present with symptoms of occupational sensitivities related to latex products can be identified and assessed. 4. Occupational health nurses are effective resources for workers and managers on issues of latex allergy and appropriate accommodation.

Decision Trees↗
PubMed1994

Entrapment of cyclodextrin-drug complexes into liposomes: potential advantages in drug delivery.

A novel concept in drug delivery discussed here, takes advantage of certain properties of the drug "containers" cyclodextrins and liposomes to combine them into a single system thus circumventing problems associated with both systems. The concept, entailing entrapment of water-soluble cyclodextrin-drug inclusion complexes in liposomes, would allow accommodation of insoluble drugs in the aqueous phase of vesicles. This would potentially increase the drug to lipid mass ratio to levels above those attained by conventional drug incorporation into the lipid phase, enlarge the range of insoluble drugs amenable to encapsulation to include, for instance, membrane destabilizing agents, allow targeting of complexes to specific sites and reduce toxicity. In the present work, soluble inclusion complexes of hydroxypropyl-beta-cyclodextrin with dehydroepiandrosterone, retinol and retinoic acid were prepared and entrapped into multilamellar liposomes by the dehydration-rehydration procedure. Complex-containing liposomes were then exposed to blood plasma. Results show that complex entrapment into liposomes depends on the lipid composition used. Nearly all of the cyclodextrin and considerable portions of the drugs were found to remain associated with the carrier in the presence of plasma.

Animals↗
PubMed1993

Polysialic acids: potential in drug delivery.

A number of bacterial polysialic acids were injected intravenously into mice. Half-lives (up to 40 h) in the blood circulation were dependent on the polysialic acid used, increased by deacylation of their phospholipid moiety, decreased with shorter chain derivatives and appeared to be dose independent. A model drug (fluorescein) covalently coupled to a polysialic acid was found to assume the half-life of its carrier. Results suggest that intact or deacylated polysialic acids and shorter chain derivatives can be used to augment the half-lives of drugs, small peptides, proteins and drug delivery systems in the blood circulation, thus prolonging their pharmacological action.

Animals↗
PubMed1992

A case study identifying nursing staffs' perception of the delivery method of nursing care in practice on a particular ward.

The research describes how nursing staff on a general surgical ward in a district general hospital perceived the delivery method of nursing care in practice. The study design was based on ethnographic methods and data were collected by diary keeping and semi-structured interviews. An organizational method based on the principles of primary nursing had been implemented on the ward for 2 years prior to the study commencing. As well as talking in general terms about primary nursing, the nursing staff talked at some length about specific issues related to their practice.

Attitude of Health Personnel↗
PubMed1990

Extracranial repair of cerebrospinal fluid fistulas: technique and results in 37 patients.

Although neurosurgeons have traditionally preferred intracranial repair for the management of cerebrospinal fluid (CSF) fistulas, this approach is associated with the complications of a craniotomy, anosmia, and a high incidence of recurrent fistulas. Extracranial repair, on the other hand, produces no central nervous system morbidity, preserves olfaction, and is associated with a low incidence of recurrence. Although there have been several reports of extracranial repair of CSF fistulas by otorhinolaryngologists, this approach has received scant mention in the neurosurgical literature. We report here our experience with 37 patients with CSF rhinorrhea or otorrhea who underwent extracranial repair. The etiology of the fistula was postoperative in 22, traumatic in 6, and spontaneous in 9. The fistulas were repaired using one of four techniques: external ethmoid-sphenoid in 18 patients, transmastoid in 9, transseptosphenoid in 7, and osteoplastic frontal sinusotomy in 3. In 32 of the 37 patients (86%) the fistulas were successfully repaired with the initial procedure. Of the 5 patients requiring a second operation, the fistula was successfully closed in 4 for an overall success rate of 97%. Complications were few and consisted of a transient facial paresis in a patient undergoing transmastoid repair and one death from meningitis. The authors conclude that because of low morbidity and mortality and a high success rate in closing fistulas, extracranial repair is the preferred technique for the operative management of CSF rhinorrhea and otorrhea.

Cerebrospinal Fluid Otorrhea↗
PubMed1989

Setting the baseline parameters for clinical assessment of foot to ground contact using the Musgrave pressure plate system.

The Musgrave Pressure Plate System for the measurement of foot contact patterns comprises two fixed pressure plates constructed from arrays of load cells, interfaced to a BBC computer. Its main advantage is the ability to measure and analyse spatial distributions of contact pressures and their time dynamics, and to do this relatively inexpensively in a clinical setting. Its main potential disadvantage is that it can disrupt the natural gait pattern by the discipline in enforces on the foot placement. The eventual aim of the project of which this study forms the pilot phase, is to develop formal decision rules based on the analysis of a large number of normal subjects for the diagnosis of abnormal foot pathology and the evaluation of therapy, using data collected by a Musgrave system. The objective of this study is to set baseline norms, and to evaluate the system. The analysis is based on 100 normal subjects using selected parameters on foot contact pressure, contact area and time, available from the system. Several stages of the foot contact process are described in terms of the selected parameters. The results show clearly that even with a relatively small subset of the available recorded data on each foot plant, a wide range of descriptive information can be accumulated. Statistically significant differences were found between the right and left feet on most of the parameters considered. However, these differences were based on a large sample and are not large in absolute terms in many instances. Therefore the observed differences may be small compared to differences between normal and abnormal cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Anthropometry↗
PubMed1989

Reinforcement of bone cement using metal meshes.

Following on from previous work reported in this journal, a practical system has been developed for in situ fibre reinforcement of bone cement in the hip joint prosthesis. A fibre preform is inserted during the operation, surrounding the metal stem of the prosthesis, forming a composite with the cement. Tests performed on full-scale models of the joint show improvements in fatigue life by more than an order of magnitude when a preform of metal fibres is used; this significantly delays the onset of cement cracking and stem loosening. Initial results reported previously suggest that other fibre materials such as carbon may give even greater improvements. Clinical trials have begun, using a form of the metal mesh.

Bone Cements↗