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Biomedical subjects

A E Powell

Publications and source records attributed to A E Powell.

At least 19 recordsLinked to original sources
PubMed2007

Exploring the relationship between senior management team culture and hospital performance.

The purpose of this study was to explore relationships between senior management team culture and organizational performance in English hospital organizations (NHS trusts [National Health Service]). We used an established culture-rating instrument, the Competing Values Framework, to assess senior management team culture. Organizational performance was assessed using a wide variety of routinely collected measures. Data were gathered from all English NHS acute hospital trusts, a total of 197 organizations. Multivariate econometric analyses were used to explore the associations between measures of culture and measures of performance using regressions, ANOVA, multinomial logit, and ordered probit. Organizational culture varied across hospital organizations, and at least some of this variation was associated in consistent and predictable ways with a variety of organizational characteristics and measures of performance. The findings provide particular support for a contingent relationship between culture and performance.

Cross-Sectional Studies↗
PubMed2004

Rhetoric and reality on acute pain services in the UK: a national postal questionnaire survey.

BACKGROUND: The study aimed to explore the extent to which NHS acute pain services (APSs) have been established in accordance with national guidance, and to assess the degree to which clinicians in acute pain management believe that these services are fulfilling their role. METHODS: A postal questionnaire survey addressed to the head of the acute pain service was sent to 403 National Health Service hospitals each carrying out more than 1000 operative procedures a year. RESULTS: Completed questionnaires were received from 81% (325) of the hospitals, of which 83% (270) had an established acute pain service. Most of these (86%) described their service as Monday-Friday with a reduced service at other times; only 5% described their service as covering 24 hours, 7 days a week. In the majority of hospitals (68%), the on-call anaesthetist was the sole provider of out of hours services. Services were categorized by respondents as thriving (30%), struggling to manage (52%) or non-existent (17%). There was widespread agreement (> or =85%) on the principles that should underpin acute pain services, and similar agreement on the need for better organizational approaches (95%) rather than new treatments and delivery techniques (19%). CONCLUSIONS: More than a decade since the 1990 report Pain after Surgery, national coverage of comprehensive acute pain services is still far from being achieved. Despite wide consensus about the problems, concrete solutions are proving hard to implement. There is strong support for a two-fold response: securing greater political commitment to pain services and using organizational approaches to address current deficits.

Attitude of Health Personnel↗
PubMed2003

Using routine comparative data to assess the quality of health care: understanding and avoiding common pitfalls.

Measuring the quality of health care has become a major concern for funders and providers of health services in recent decades. One of the ways in which quality of care is currently assessed is by taking routinely collected data and analysing them quantitatively. The use of routine data has many advantages but there are also some important pitfalls. Collating numerical data in this way means that comparisons can be made--whether over time, with benchmarks, or with other healthcare providers (at individual or institutional levels of aggregation). Inevitably, such comparisons reveal variations. The natural inclination is then to assume that such variations imply rankings: that the measures reflect quality and that variations in the measures reflect variations in quality. This paper identifies reasons why these assumptions need to be applied with care, and illustrates the pitfalls with examples from recent empirical work. It is intended to guide not only those who wish to interpret comparative quality data, but also those who wish to develop systems for such analyses themselves.

Benchmarking↗
PubMed2001

Nucleoside transporter subtype expression: effects on potency of adenosine kinase inhibitors.

1. Adenosine kinase (AK) inhibitors can enhance adenosine levels and potentiate adenosine receptor activation. As the AK inhibitors 5' iodotubercidin (ITU) and 5-amino-5'-deoxyadenosine (NH(2)dAdo) are nucleoside analogues, we hypothesized that nucleoside transporter subtype expression can affect the potency of these inhibitors in intact cells. 3. Three nucleoside transporter subtypes that mediate adenosine permeation of rat cells have been characterized and cloned: equilibrative transporters rENT1 and rENT2 and concentrative transporter rCNT2. We stably transfected rat C6 glioma cells, which express rENT2 nucleoside transporters, with rENT1 (rENT1-C6 cells) or rCNT2 (rCNT2-C6 cells) nucleoside transporters. 3. We tested the effects of ITU and NH(2)dAdo on [(3)H]-adenosine uptake and conversion to [(3)H]-adenine nucleotides in the three cell types. NH(2)dAdo did not show any cell type selectivity. In contrast, ITU showed significant inhibition of [(3)H]-adenosine uptake and [(3)H]-adenine nucleotide formation at concentrations < or =100 nM in rENT1-C6 cells, while concentrations > or =3 microM were required for C6 or rCNT2-C6 cells. 4. Nitrobenzylthioinosine (NBMPR; 100 nM), a selective inhibitor of rENT1, abolished the effects of nanomolar concentrations of ITU in rENT1-C6 cells. 5. This study demonstrates that the effects of ITU, but not NH(2)dAdo, in whole cell assays are dependent upon nucleoside transporter subtype expression. Thus, cellular and tissue differences in expression of nucleoside transporter subtypes may affect the pharmacological actions of some AK inhibitors.

Adenine Nucleotides↗
PubMed2001

Reading and assessing qualitative research.

What makes doctors burn out? What is it like to have epilepsy? Why do smokers not give up? Qualitative research makes it possible to look behind the statistics and to study health and health care from the inside: to find out what it is really like for the health professionals who provide the care and for the patients on the receiving end.

Data Collection↗
PubMed1990

Variation of resorption rates in vivo of various bones in immature rats.

The 3H-tetracycline method of measuring bone resorption in vivo was applied to the comparison of various whole bones in rats of two different ages. The rat was chosen because it grows via modelling processes and contains little, if any, cortical remodelling except for a small amount of trabecular remodelling. It was found that resorption rates in vivo are high and similar in almost all of the 18 bones measured between birth and 2 weeks of age. However, in weanling rats studied at 4-6 weeks of age, resorption rates in the skull and in the long bones had decreased significantly while remaining high in the vertebrae, scapula, sternum and pelvis. Bones of neonatal rats were quite alike in their rates of bone resorption, but the bones of the weanlings manifested significant heterogeneity in their rates. It is known that anatomic heterogeneity of metabolic turnover of various bones characterizes the mature state in humans and dogs as well. The present data are unique in that they reflect absolute resorption rates in vivo uncomplicated by the extensive re-utilization of calcium inherent in other isotopic or non-isotopic protocols.

Animals↗
PubMed1987

Biology of cancellous bone grafts.

Despite 30 years of experimental bone grafting research, the fresh cancellous bone graft remains the most osteogenic and reliable bone grafting material. Recent experimental data suggest that modification of the graft-host interaction by antigen matching or immune manipulation may allow increasingly successful use of allografts.

Animals↗
PubMed1985

Effects on bone of vascular interruption. Turnover and morphology in isotope-prelabelled rats.

The effects of bone devascularization were evaluated histologically and metabolically in rats prelabelled with 45Ca, 3H-tetracycline and 3H-proline by quantifying cortical bone resorption and formation. The interruption of blood supply to bone without invading its integrity resulted in a marked increase in bone turnover (resorption and formation) during the first and second months. The stimulated increase in bone resorption and formation did not affect the resultant mass of collagen and calcium. Thus, the increase in bone resorption was compensated by an equivalent increase in bone formation.

Animals↗
PubMed1984

Improved acceptance of frozen bone allografts in genetically mismatched dogs by immunosuppression.

UNLABELLED: We studied the role of immunosuppressive therapy in improving the incorporation of frozen bone allografts exchanged across strong transplantation barriers in a canine cancellous ulnar segmental replacement model. Dogs receiving frozen bone from donors with major histocompatibility differences received one of three different immunosuppressive treatments. In two groups, azathioprine and prednisolone were administered for either twenty-eight or fifty-six days; anti-lymphocyte globulin was added for another twenty-eight-day group in a third regimen. Frozen bone was evaluated radiographically and histologically by criteria that quantified the biological characteristics of the bone itself and union between the graft and host at thirteen and twenty-six weeks after grafting. Graft incorporation in these animals was compared with graft acceptance in a similar group of untreated animals and in untreated animals in which bone was exchanged across weak transplantation barriers. Complications of immunosuppression included wound drainage, infection, weight loss, and falling white-blood-cell counts. Seven of the original thirty-seven animals died as a direct result of these complications. After twenty-six weeks the grafts in the recipients receiving immunosuppression appeared radiographically and histologically indistinguishable from those in the untreated, genetically closely matched group and from autografts. They were significantly better incorporated than identical allografts placed in untreated, genetically disparate recipients. There was no difference in the effectiveness of any of the immunosuppressive programs. CLINICAL RELEVANCE: Immunosuppression improves the biological outcome of otherwise poorly performing frozen bone allografts in dogs. This finding suggests that treatments that modify the immunological response of the host without major side effects may be useful clinically in improving the success of massive frozen bone allografts.

Animals↗
PubMed1983

The effect of histocompatibility matching on canine frozen bone allografts.

The value of histocompatibility matching in frozen bone allografts was studied in a canine cancellous ulnar segmental-replacement model. Frozen bone that was exchanged across strong and weak transplantation barriers was evaluated histologically and radiographically at thirteen and twenty-six weeks after grafting. Histological grading criteria quantified the type of union at each end of the graft and the degree of remodeling of the marrow, spongiosa, and compacta. Radiographic grading criteria included the presence of union at each end of the graft and the degree of remodeling of the graft segment. In vitro studies for serum antibody and cell-mediated immunity were carried out by isotopic cytotoxicity methods at seven intervals during the twenty-six-week study period. Histologically, the strong-barrier allografts had fewer osseous unions and less reorganization of spongiosa and marrow when compared with autograft controls at both thirteen and twenty-six weeks. Radiographically, the strong-barrier allografts at thirteen weeks had fewer unions and marked resorption of grafts material when compared with autograft controls. There were no differences between weak transplantation-barrier grafts and control autografts radiographically or histologically at thirteen and twenty-six weeks after grafting. Frozen bone allografts did not elicit detectable serum antibody or lymphocytes that were cytotoxic for donor cells.

Animals↗
PubMed1982

Cell populations in leucocyte adherence inhibition: requirement for T lymphocytes with IgG Fc receptors.

The subset identity of T lymphocytes participating in the leucocyte adherence inhibition (LAI) reaction was investigated. Humans were immunized with keyhole limpet haemocyanin (KLH) and their cellular immunity was tested by means of the haemocytometer variant of the LAI method. Their lymphocytes were fractionated by rosetting methods employing neuraminidase-treated sheep erythrocytes and IgG- or IgM-coated ox erythrocytes. The T lymphocytes rosetted by IgG-coated ox cells (T gamma) reacted with KLH to give specific LAI reactions. Non-T gamma cells failed to react. The T gamma cells released a lymphokine which caused an LAI reaction of T lymphocytes from non-immunized donors. Immune non-T gamma cells, when incubated with KLH yielded inactive supernates. The normal cells which gave positive LAI responses to the lymphokine also proved to belong exclusively to the T gamma subclass. Cells positively selected with IgM-coated ox cells (T micro) were inactive while the non-T micro lymphocytes behaved like the T gamma cells. It was shown that the activity was confined to the T gamma subset throughout the time course of a primary immune response. Thus, LAI reactivity appears to be a property of a very small subclass of lymphocytes which communicate with each other by means of a soluble factor.

Hemocyanins↗
PubMed1978

Leukocyte-adherence inhibition: a specific assay of cell-mediated immunity dependent on lymphokine-mediated collaboration between T lymphocytes.

The leukocyte-adherence inhibition (LAI) assay was studied to determine its immunologic relevance and identify the cell populations on which it depends. Two systems were employed: peripheral blood leukocytes from humans immunized with KLH, and lymph node cells from rats immunized with DNP-BCG. In both cases, LAI responses appeared about 3 to 4 days after immunization, reached a peak about 3 to 4 weeks later, and diminished thereafter. Reimmunization resulted in a booster-like response. LAI analysis in both systems showed dose-response dependency. Responses could be elicited only with the immunizing antigen. Virtual depletion of phagocytic cells had no effect on the response. E-rosette-forming cells gave an excellent response to KLH and also produced an active supernatant (lymphokine). Cells not forming spontaneous E-rosettes were inactive and could not produce active supernatants. Only those nonimmune cells that formed E-rosettes could respond to active supernatants. Thus, the LAI response is a specific indicator of cell-mediated immunity. T lymphocytes probably are required both at the antigen-reactive stage and at the stage of responding to the T cell-dependent lymphokine.

Animals↗
PubMed1975

Specific responsiveness of leukocytes to soluble extracts of human tumors.

The leukocyte adherence inhibition (LAI) method was studied with respect to its specificity in detecting responses to extracts of tumor tissues or normal lymphocytes. Responses of cells from normal persons were within 10% of each other whether incubation was carried out with culture medium alone or with any of the extracts. The same was true of cells from 78 cancer patients unless the cells were incubated with extracts of the same histologic type as their own. In the latter case, statistically significant responses occurred in 95% of the 110 analyses done. Negative responses were given by cells from 14 patients tentatively diagnosed as having breast carcinoma but whose lesions later proved benign. There was one positive response inconsistent with the diagnosis. Of 29 normal individuals known to have been exposed to tumors or tumor extracts, 11 responded positively and specifically to the relevant tumor extract. Cells from 12 of 30 multiparous female breast-cancer patients responded to extracts of pooled normal lymphocytes. The results establish that the LAI analysis is an extremely specific means of detecting systemic responses to malignant diseases. In addition, analyses have proven positive in 95% of the cases studied.

Antigens, Neoplasm↗