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Biomedical subjects

A Brennan

Publications and source records attributed to A Brennan.

At least 73 records · Page 4Linked to original sources
PubMed1983

Identification of a clonally restricted 90 kD heterodimer on two human cloned natural killer cell lines. Its role in cytotoxic effector function.

The present studies were carried out to identify surface molecules involved in the cytotoxic effector function of a human natural killer (NK) clone termed JT9. This clone represents a mature T lymphocyte (T3+T8+T11+) mediating NK-like activity. Using JT9 for immunization, one monoclonal antibody termed anti-NKTa was selected that blocked the cytotoxicity of the clone towards K562 cells. Reactivity of anti-NKTa antibody was assessed using a large panel of lymphoid and nonlymphoid cells including a variety of cloned cell lines with either cytotoxic T lymphocyte (CTL) or NK-like activity. Among all cells tested, only two individual clones, JT9 and JT10, were found to express NKTa antigen. JT10 was derived independently from the same individual as JT9 and also represents a mature T cell (T3+T8+T11+) mediating NK-like activity. Like the Ti structure on CTL clones, the molecule defined by anti-NKTa was shown to be membrane associated with T3 in co-modulation experiments. Moreover, anti-NKTa precipitated a 90 kD heterodimeric structure in sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of 125I surface-labeled JT9 cells. The blocking capacity of anti-NKTa was evaluated in cytotoxicity assays using a panel of target cells. The influence of anti-T3 was tested in parallel and it was found that both anti-NKTa and anti-T3 blocked the cytotoxicity of the cloned cells against all targets. Given the potential role of 90 kD molecules as antigen-receptor structures, the specificity of the two NKTa+ NK clones was compared and found superimposable when assessed using 15 in vitro established cell lines. However, in contrast to conventional CTL clones, the expression of cytotoxicity by JT9 and JT10 was not dependent upon recognition of class I or class II major histocompatibility complex gene products on the target cells. In addition, the cytotoxicity of these T8+ NK active clones could not be blocked by anti-T8 antibodies. Taken together, the present data suggest that the specificity of one population of human NK active lymphocytes is determined by clonotypic structures. The NKTa determinant identified here appears to belong to the same family of molecules as Ti structures, previously identified on antigen-specific T lymphocytes.

Antibodies, Monoclonal↗
PubMed1980

Shedding of surface proteins by porcine thyroid cells.

Isolated porcine thyroid cells were surface-labelled with 125I using the lactoperoxidase technique. Samples of the cells were then cultured and harvested at various intervals for up to 7 days. The labelled proteins remaining on the cells or shed into the culture medium were analysed by electrophoresis on polyacrylamide gels run in sodium dodecyl sulphate. These studies indicated that the several different surface proteins of the thyroid cells were lost from the cell surface at similar rates (half-time of approximately 28 h) as the result, at least in part, of a process which depended on active cell metabolism. In addition, the gel profiles obtained from analysis of both medium and membrane-bound labelled proteins were similar and this suggested that peptide cleavage was not involved in the shedding of the majority of these proteins.

Animals↗
PubMed1978

Successful immunosuppression of renal allograft recipients with alternate day steroid therapy.

Twenty-five renal transplant recipients have been treated long-term with immunosuppressive therapy with conversion from a daily dose to an every other day dose of steroids in conjunction with daily administration of Imuran. The patients were selected by having stable grafts for 6 to 9 months prior to conversion, not by the presence of steroid-induced complications. Alternate day steroid administration has continued to provide successful immunosuppression in that only of 25 patients (4%) has had any evidence of renewed rejection activity during a treatment interval of 7--95 months, median 22 months and mean 28 months. One graft was lost to an acute rejection reaction that occurred in association with a flu-like syndrome 8 months after the conversion was started. It is concluded that in the patient with documented stability of the graft, every other day steroid administration is a successful immunosuppressive regimen.

Adolescent↗
PubMedDate not supplied

Diabetes mellitus: biomedical health education/promotion approach.

Diabetes mellitus causes numerous difficulties for those who adopt a biomedical health education/promotion approach. Its management regimen is notoriously complex, being affected by variety of cognitive, psychosocial and environmental factors. However, a valuable contribution of biomedical research in this area has been the corroboration by empirical studies that dispositional characteristics have little to do with adherence/non-adherence behaviours. Criticisms of the biomedical approach include its omission of the psychosocial correlates of health and illness, and its health expert and individualistic orientation. In critically appraising the biomedical model and its related health education/promotion approaches, this article will briefly describe the model and its origins and critically review its strengths and weaknesses. It will then examine some of the empirical problems associated with the measurement of compliance, metabolic control and self-management as evaluatory outcomes in diabetes.

Diabetes Mellitus↗
PubMedDate not supplied

Efficacy of cardiac rehabilitation. 1: A critique of the research.

This article, the first of two parts, suggests that cardiac rehabilitation has two primary foci: the reduction of morbidity and mortality, and the amelioration of distress associated with cardiac pathology. While exercise programmes figure prominently in cardiac rehabilitation, empirical studies attest to their relatively modest impact on the recurrence of myocardial infarction. Other interventions such as stress management programmes reduce psychological distress and increase effective coping mechanisms, but only for a limited period. Traditional educational programmes compare unfavourably with cognitive-behavioural interventions. Empirical research appraising the efficacy of many cardiac rehabilitation interventions are tainted by numerous design problems. The second part of this article considers research into the efficacy of smoking cessation and type A behaviour modification programmes.

Exercise Therapy↗
PubMedDate not supplied

Efficacy of cardiac rehabilitation 2: Smoking and behaviour modification.

The first part of this article (Vol 6(12): 697-702) critically reviewed the research on the acclaimed beneficial effects of a number of cardiac rehabilitation programmes including exercise, stress management and educational interventions. This article will examine empirical studies on the efficacy of smoking cessation and type A behavioural modification programmes. Lamentably, few studies have been conducted on the efficacy of smoking cessation. Caution is indicated when establishing conclusions from studies on type A behaviour given the conceptual problems of this construct, i.e. its inability to consistently predict coronary heart disease, evidence of confusion surrounding the improper use of the psychometric measures and the neglect of salient psychosocial baseline variables. A number of clinical implications and future directions for research are indicated.

Behavior Therapy↗
PubMedDate not supplied

Analysing mandatory continuing education.

Of all the contentious issues surrounding the United Kingdom Central Council's continuing education proposals, the introduction of mandatory continuing education is perhaps the most controversial. This article sets out the issues surrounding it, including the postulated infringement of the voluntary principles of adult education, the effect it has on the learning process, and the possibility of it leading to uniform and inferior learning. The main issue, however, is whether mandatory continuing education achieves its objective of enabling staff to improve their practice. More research is required, the author argues, before this crucial question can be answered.

Cross-Cultural Comparison↗
PubMedDate not supplied

Preceptorship: is it a workable concept?

Preceptorship has many advantages to offer newly graduated nurses. The author of this article warns, however, that the mistakes made in mentorship should be heeded and its use in practice evaluated thoroughly before it is adopted without question.

Education, Nursing↗
PubMedDate not supplied

Clinical and neuropsychological correlates of impaired awareness of deficits in Alzheimer disease and Parkinson disease: a comparative study.

OBJECTIVE: To compare patients with Alzheimer disease (AD) and Parkinson disease (PD) with regard to their awareness of cognitive, emotional/social interaction, self-care, and motor-related neurologic deficits. BACKGROUND: Unawareness of deficits, a clinically important symptom, is found in AD. It has been hypothesized to be associated with disruption of frontal-subcortical circuits but has been little studied in other neurodegenerative disorders. Because PD has a different anatomic-pathologic substrate, a comparison of impairment of awareness in AD and PD may shed light on the neural basis of this phenomenon. METHOD: Impairment of awareness was measured as the difference between patient self-report and caregiver ratings of patient abilities on questionnaires tapping cognitive, emotional/social interaction, self-care, and motor function. These "discrepancy scores" were then compared between the two diagnostic groups and examined in relation to selected neuropsychological test data. RESULTS: In general, both AD and PD patients rate themselves as being less impaired than do their caregivers. The two diagnostic groups, AD and PD, differ significantly, however, on awareness discrepancy measures in the cognitive domain. In their ratings of patient cognitive skills, AD caregivers rate patients as significantly more impaired than patients rate themselves, whereas PD caregivers and patients do not differ significantly on these ratings. Impaired awareness in PD but not in AD is associated with poorer overall cognitive function and performance on tests measuring memory, attention, and constructional ability. CONCLUSIONS: Both AD and PD patients display impaired awareness of deficits in multiple domains, including motor-related neurologic function. Parkinson disease patients with comparatively intact cognitive function display relatively preserved awareness of motor and other deficits.

Aged↗
PubMedDate not supplied

Clinicians' conundrum.

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Decision Making↗