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Biomedical subjects

S Stephenson

Publications and source records attributed to S Stephenson.

At least 19 recordsLinked to original sources
PubMed2000

Selective omission of the donor cross-match before renal transplantation: efficacy, safety and effects on cold storage time.

BACKGROUND: A donor lymphocyte cross-match (XM) test performed before renal transplantation is considered mandatory but may delay the transplant and increase the cold storage time. With careful documentation of sensitizing events and with knowledge of previous antibody screening results, it is often possible to predict the XM result for a given donor HLA mismatch. In this study, a policy was adopted of omitting the pretransplant XM in patients in whom a negative result was predicted with absolute confidence. METHODS: Recipients were selected for cadaveric donor kidney transplantation using a computer algorithm based on HLA match, sensitization status, time on the waiting list and donor and recipient age. The immediate pretransplant cross-match test was omitted in non-sensitized recipients and in sensitized recipients where antibody specificities were precisely defined and not against donor HLA. RESULTS: From October 1997 to May 1999, 53 of 96 (55%) consecutive cadaveric kidney donor transplants were performed without a pretransplant XM. In all cases, a negative donor HLA-specific antibody XM was confirmed after transplantation. Omission of the pre-transplant XM was associated with a significant reduction in cold ischemic time (15.0 hr vs. 18.2 hr, P=0.01) and a reduced incidence of delayed graft function (13% vs. 33%, P=0.03). However, there was no difference in transplant outcome at 1 year. CONCLUSION: Rigorous attention to priming events together with careful antibody screening allows the pre-transplant XM test to be safely omitted in approximately half the patients awaiting renal transplantation. This policy allows a modest reduction in cold ischemia time, but it remains to be seen whether this is of clinical benefit.

Adult↗
PubMed2000

The use of a hydrophobic matrix for the sustained release of a highly water soluble drug.

An experimental investigation into the use of a hydrophobic matrix to control the release of a highly water soluble drug was undertaken. Matrices consisting of hydrogenated vegetable oil and calcium sulfate with a 4% drug loading showed a sustained-release profile of up to 24 hr. The release mechanism from such matrices seemed to obey both root time kinetics and first-order behavior. Investigations showed that the effect of geometry had a significant effect on the drug release rate.

Algorithms↗
PubMed1999

Primordial prevention of cardiovascular disease through applied genetics.

Primordial prevention might be considered prevention of the development of disease at its earliest stages or early intervention on risk factors to eliminate increased risk in the first place. In this review we consider how knowledge of genetic causes of early cardiovascular disease can lead to directed screening and better treatment of high risk individuals. While gene therapy would be the most "primordial" approach to prevention of some diseases such as familial hypercholesterolemia, its practical application remains on the horizon. Nevertheless, there is much we can do now to prevent early deaths in genetically high risk patients. Here we consider epidemiology as the parent discipline for applied genetics and as integral to primordial prevention. With new knowledge of special susceptibility and new understanding of the interaction of genetics and exposures, prevention of individual high-risk in the first place is realizable. We summarize here the known and candidate genes influencing atherosclerosis, hypertension, and thrombosis; their diagnosis; and some useful preventive approaches. MEDPED, an international scheme for detection of risk in medical pedigrees, is described, along with the cost and social implications of its application as a preventive strategy.

Cardiovascular Diseases↗
PubMed1998

Neurological rehabilitation in Indonesia and the UK: differences and similarities.

Both countries face considerable challenges to their rehabilitation services. Although contextually different, the problems and challenges are common to both. Two contrasting views of disability have been presented. In the UK disability may be viewed as a disaster, while in Asia illness and disability may be viewed as inevitable. Personal independence is not a universal goal of rehabilitation, because in some cultures dependence on others is an expected consequence of disability. Disability in Indonesia translates into a large burden of care for the family, whereas English families may expect greater help from the government in caring for their relative. Western rehabilitation is increasingly patient directed, whereas the Indonesian model is more likely to be determined solely by professionals. The problems observed by the team in Indonesia were remarkably similar to those experienced in the UK. A patient centered goal setting approach can be considered vital to neurological rehabilitation, although the focus of the goals set is likely to be very different in these two cultures. The fundamental importance of a multidisciplinary team is recognized in both cultures, although team working may not be easy in either situation. Managerial commitment is essential for the survival of a team, yet both structures sometimes fail to provide the necessary support. Hierarchical leadership can inhibit team development both in the UK and in Indonesia, as can frequent rotation of staff. Prescription of therapy by doctors inhibits the development of therapists in both cultures, and therefore the overall effectiveness of the team. In both the UK and Indonesia, the value of rehabilitation as a specialty is not widely recognized. The absence of life and death situations means that services are often out of the public eye, and poorly understood. However, the prevalence of disability will increase the need for rehabilitation services worldwide. Many challenges remain in both the UK and Indonesia to the development of more effective rehabilitation services. Issues like the lack of recognition of rehabilitation as a specialty, the importance of team work, the paucity of managerial support, and increasing demand for rehabilitation services will need to be recognized and addressed. Despite the different approaches to disability in the two cultures, the problems faced are similar. These problems will need to be solved if there is to be significant progress in this multidisciplinary field.

Attitude to Health↗
PubMed1996

Positive selection by thymic nurse cells requires IL-1 beta and is associated with an increased Bcl-2 expression.

A temperature-sensitive line of thymic nurse cells (tsTNC-1) that maintains the ability to selectively internalize immature alpha beta TCRloCD4+CD8+ thymocytes in vitro was used in long-term coincubation experiments to determine nurse cell function during the process of MHC restriction. The thymocyte subset released from its association with TNCs contained both viable and apoptotic cells. The cells that remained within intracytoplasmic vacuoles died through the process of programmed cell death. Surviving or rescued thymocytes in the released population displayed an increase in Bcl-2 protein expression. The rescue activity of TNCs was drastically reduced with the addition of antibodies against either class I or class II MHC antigens to cocultures. A subset of the TNC-rescued population matured from the alpha beta TCRloCD69- phenotype to alpha beta TCRhiCD(69+)-expressing cells only when IL-1 beta was added to cocultures. These results suggest that TNC rescue of early double-positive thymocytes from apoptosis is associated with an interaction between the TCR and the MHC and the onset of Bcl-2 expression. Maturation of thymocytes within the TNC-rescued population requires the costimulatory effects of IL-1 beta.

Animals↗
PubMed1996

Injury in rugby league: a four year prospective survey.

OBJECTIVE: To investigate the incidence of injury in English professional rugby league over a period of four playing seasons. METHODS: All injuries that were received by players during match play were recorded. Each injury was classified according to site, type, player position, team playing for, activity at the time of injury, and time off as a result of injury. RESULTS: The overall injury rate was 114 (95% confidence interval 105 to 124) per 1000 playing hours, the most frequent type of injury were muscular injuries [34 (29 to 40) per 1000 playing hours], while the most frequently injured site was the head and neck region [38 (16 to 25) per 1000 playing hours]. Players received the largest percentage of injuries when being tackled [46.3% (41.9 to 50.7)], most injuries required less than one week away from playing and training [70.1% (66.1 to 74.2)], and forwards had a higher injury rate than backs (139 v 93 injuries per 1000 hours). CONCLUSIONS: The high rates of injury in rugby league are undoubtedly due to the high amount of bodily contact in the game. Being tackled has the highest risk of injury, because of being hit forcibly by other players. Forwards suffer higher injury rates than backs, probably because they are involved in a larger number of physical collisions.

Craniocerebral Trauma↗
PubMed1994

Prisms glitters.

In days past, employees ate almost anywhere but the cafeteria of the Butterworth Hospital in Grand Rapids, Mich. That's not true anymore.

Food Service, Hospital↗
PubMed1993

Cognitive strategies and hypothesis testing during discrimination learning in Parkinson's disease.

This study investigated the nature and extent of impairments in the use of hypotheses and cognitive strategies in medicated subjects with idiopathic Parkinson's disease (PD) and matched control subjects. PD subjects did not differ from controls in solving one- or two-dimensional discrimination learning problems, but showed impairment on four-dimensional problems which did not appear to be attributable to memory deficits. They achieved fewer correct solutions, used fewer hypotheses, and were less likely to use appropriate lose-shift strategies following negative feedback. The pattern of findings was similar to those previously reported for subjects with frontal lobe lesions.

Aged↗
PubMed1992

Job$ '92.

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Administrative Personnel↗