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Biomedical subjects

A Edwards

Publications and source records attributed to A Edwards.

At least 73 records · Page 4Linked to original sources
PubMed2001

Aerobic biotransformation of 4-fluorocinnamic acid to 4-fluorobenzoic acid.

The biotransformation of 4-fluorocinnamic acid (FCA) using non-acclimated industrial activated sludge was investigated. FCA is a common intermediate in organic synthesis, and it is often present in aqueous waste streams. Hence, the biotransformation reactions this compound undergoes when exposed to activated sludge micro-organisms should be understood before waste streams are sent to biological wastewater treatment plants (WWTPs). FCA biotransformation was monitored using a wide range of analytical techniques. These techniques were used to monitor not only FCA disappearance, but also the formation of degradation products, in order to propose the metabolic pathway. FCA was biotransformed to 4-fluorobenzoic acid via the formation of 4-fluoroacetophenone. The removal of FCA up to 200 mg L(-1) followed first order kinetics. The half-lives for removal of FCA from the test solutions supplied with 200 mg L(-1), 100 mg L(-1), and 50 mg L(-1) were 53, 18, and 5 hours respectively.

Aerobiosis↗
PubMed2001

Shared decision making observed in clinical practice: visual displays of communication sequence and patterns.

UNLABELLED: The aim of the study was to examine the communication strategies of general practitioners attempting to involve patients in treatment or management decisions. This empirical data was then compared with theoretical 'competences' derived for 'shared decision making'. The subjects were four general practitioners, who taped conducted consultations with the specific intent of involving patients in the decision-making process. The consultations were transcribed, coded into skill categorizations and presented as visual display using a specifically devised sequential banding METHOD: The empirical data from these purposively selected consultation from clinicians who are experienced in shared decision making did not match suggested theoretical frameworks. The views of patients about treatment possibilities and their preferred role in decision making were not explored. The interactions were initiated by a problem-defining phase, statements of 'equipoise' consistently appeared and the portrayal of option information was often intermingled with opportunities to allow patients to question and reflect. A decision-making stage occurred consistently after approximately 80% of the total consultation duration and arrangements were consistently made for follow-up and review. Eight of the 10 consultations took more than 11 min - these specific consultations were characterized by significant proportions of time provided for information exchange and patient interaction. The results demonstrate that some theoretical competences are not distinguishable in practice and other stages, not previously described, such as the 'portrayal of equipoise', are observed. The suggested ideal of a shared decision-making interaction will either require more time than currently allocated, or alternative strategies to enable information exchange outside the consultation.

Adult↗
PubMed2001

Consumers' views of quality in the consultation and their relevance to 'shared decision-making' approaches.

BACKGROUND: There is a recognized need to assess the effects of shared decision-making and other communication interventions. However, the outcomes usually assessed for evidence of 'effectiveness' are determined by researchers and have not been based on consumers' views. AIM: This study aimed to identify the important outcomes of consultations for consumers, and to compare with those reported in the current literature. SETTING AND PARTICIPANTS: Forty-seven participants attending six focus group interviews. Most interviews took place in and all were orientated towards the UK primary care setting. METHODS: Focus group study. RESULTS: Many affective outcomes were identified, consistent with the current literature trends. However, many cognitive and behavioural outcomes that are assessed in the current literature were not noted by participants as important. Furthermore, a broader range of outcomes than is evident in the current literature was viewed as important to these participants. CONCLUSIONS: There is a need to revisit the outcomes which are assessed in decision-making and communication research. The outcomes of greatest importance to consumers must be identified and confirmed by new research which is based directly on the views of consumers themselves.

Consumer Behavior↗
PubMed2001

Attenuation of neurotoxicity in cortical cultures and hippocampal slices from E2F1 knockout mice.

The E2F1 transcription factor modulates neuronal apoptosis induced by staurosporine, DNA damage and beta-amyloid. We demonstrate E2F1 involvement in neuronal death induced by the more physiological oxygen-glucose deprivation (OGD) in mouse cortical cultures and by anoxia in mouse hippocampal slices. E2F1(+/+) and (-/-) cultures were comparable, in that they contained similar neuronal densities, responded with similar increases in intracellular calcium concentration ([Ca(2+)]i) to glutamate receptor agonists, and showed similar NMDA receptor subunit mRNA expression levels for NR1, NR2A and NR2B. Despite these similarities, E2F1(-/-) cultures were significantly less susceptible to neuronal death than E2F1(+/+) cultures 24 and 48 h following 120-180 min of OGD. Furthermore, the absence of E2F1 significantly improved the ability of CA1 neurons in hippocampal slices to recover synaptic transmission following a transient anoxic insult in vitro. These results, along with our finding that E2F1 mRNA levels are significantly increased following OGD, support a role for E2F1 in the modulation of OGD- and anoxia-induced neuronal death. These findings are consistent with studies showing that overexpression of E2F1 in postmitotic neurons causes neuronal degeneration and the absence of E2F1 decreases infarct volume following cerebral ischemia.

Animals↗
PubMed2001

Antibiotics and shared decision-making in primary care.

Antibiotics are often prescribed to patients with respiratory tract infections who are unlikely to benefit. Models of physician-patient interaction may help understanding of this problem and inform the design of communication skills interventions to enhance appropriate prescribing. The 'paternalistic model' of the consultation remains common in the setting of acute respiratory tract infections. However, the four assumptions that could support this model are not valid for most of these patients, because: best treatment is controversial; management is inconsistent; physicians are not in the best position to evaluate trade-offs between management options without understanding patients' perspectives; and many pressures (apart from patients' agendas) intrude into the consultation. One alternative is the 'informed model' of consulting, but this does not take society's interests into account. The 'shared decision-making model', however, provides a framework for addressing both clinicians' and patients' agendas, and could guide the development and evaluation of specific consultation strategies to promote more appropriate use of antibiotics in primary care.

Anti-Bacterial Agents↗
PubMed2001

The mechanical behavior of vascular grafts: a review.

The development of intimal hyperplasia (IH) near the anastomosis of a vascular graft to artery is directly related to changes in the wall shear rate distribution. Mismatch in compliance and diameter at the end-to-end anastomosis of a compliant artery and rigid graft cause shear rate disturbances that may induce intimal hyperplasia and ultimately graft failure. The principal strategy being developed to prevent IH is based on the design and fabrication of compliant synthetic or innovative tissue-engineered grafts with viscoelastic properties that mirror those of the human artery. The goal of this review is to discuss how mechanical properties including compliance mismatch, diameter mismatch, Young's modulus and impedance phase angle affect graft failure due to intimal hyperplasia.

Biocompatible Materials↗
PubMed2001

Accuracy and modifying factors of the sonographic estimation of fetal weight in a high-risk population.

There have been a number of reviews assessing the accuracy of different methods of sonographic estimation of fetal weight, without identifying any clearly superior equation. In order to optimise accuracy in a high-risk population, we decided to compare some of the most popular early equations with the newer volume-based equations, and to try and identify factors that affect the ability of these equations to estimate fetal weight accurately We collected the scan and delivery details of 192 fetuses born within one week of a sonographic estimation of fetal weight. We then applied three of the most popular equations and two newer volume-based equations to the recorded fetal biometric parameters to assess the performance of each equation overall, and under varying maternal, fetal, and scan conditions. The equations of Shepard, Hadlock A, Hadlock B and Combs produced similar results with systematic (mean) errors in the range 1.2-1.9% and random error characterised by one standard deviation in the range of 8.6-9.5%. Dudley's volume-based equation produced a significant systematic error in the form of a mean error of 7.4%, which corresponds to a mean birthweight (BW) which is 7.4% above the mean estimated fetal weight (EFW). When we stratified the study group by birthweight, Combs' equation produced significant differences in the mean error, (p < 0.00001), that ranged from a mean overestimation in fetal weight of 8.5% for babies with BW < 1000 g to a mean underestimation in fetal weight of 6.2% for babies with BW > 3000 g. Oligohydramnios resulted in a trend towards an increased mean error for all equations which was only statistically significant for Hadlock B. The equations Shepard and Hadlock A performed best in our high-risk population. They produced the smallest systematic errors across the entire study group and were not adversely affected by variations in birthweight, liquor volume, or fetal presentation. The newer, volume-based equations were disappointing, producing large systematic errors. Large random errors in all equations continue to be the Achilles' heel that limit the value of sonographic EFW.

Biometry↗
PubMed2001

A case of Brown-Sequard syndrome with associated Horner's syndrome after blunt injury to the cervical spine.

A 26 year old motorcyclist was received by the trauma team in our accident and emergency department after a head on collision with a motor vehicle. He had been correctly immobilised and his primary survey was essentially normal. He was alert and orientated with a Glasgow Coma score of 15 and had no symptoms or signs of spinal injury. His cervical spine radiography was also normal. Neurological examination however, revealed anisocoria, his left pupil being smaller than his right, and a Brown-Sequard syndrome, with a sensory level at C6. Immobilisation was maintained and he was transferred to the regional neurosurgical centre where magnetic resonance imaging revealed a contusion of the left half of the spinal cord adjacent to the 6th cervical vertebrae. Computed tomography revealed no bony injury but spinal column instability was demonstrated after flexion-extension spinal views and he underwent surgery to fuse his spine at the C5-C6 level. This report highlights the necessity to observe strict ATLS guidelines. This must include a thorough examination of the central and peripheral nervous system where spinal injury is suspected, even in the absence of radiographic abnormality and neck pain. This article also presents the unusual phenomena of Brown-Sequard syndrome and unilateral Horner's syndrome after blunt traumatic injury to the cervical spine.

Accidents, Traffic↗
PubMed2001

Understanding risk and lessons for clinical risk communication about treatment preferences.

This paper defines risk and its component elements and describes where clinical practice may be starting from in terms of what is reported in the literature about understanding risks and the information requirements of consumers. It notes briefly how theoretical models in the literature contribute to our understanding by providing a basis from which to summarise current evidence about the effects of healthcare interventions which address risks and risk behaviour. The situations or types of interventions in which risk related interventions are most effective are described, but a significant caveat is noted about the types of outcomes which have been reported in the literature and which are most appropriate to evaluate. The effects of "framing" variations in the information given to consumers and the ethical dilemmas these raise for a debate about "informed choice" in healthcare programmes are discussed. In response to both the practical and ethical dilemmas that arise from the current evidence, some of the areas where attention should be focused in the future are outlined so that both health gain and informed choice might be achieved. These include the use of decision aids, although their implementation is not widespread at present. Lessons from the current literature on how further progress can be made towards improved communication, discussion between professionals and consumers, and enhancing informed choice are discussed.

Communication↗
PubMed2001

Transport of plasma proteins across vasa recta in the renal medulla.

In this study, we have extended a mathematical model of microvascular exchange in the renal medulla to elucidate the mechanisms by which plasma proteins are transported between vasa recta and the interstitium. In contrast with other work, a distinction was made between the paracellular pathway and the transcellular route (i.e., water channels) in descending vasa recta (DVR). Our model first indicates that concentration polarization on the interstitial side of vasa recta has a negligible effect on medullary function. Our results also suggest that, whereas proteins are cleared from the interstitium by convection, both diffusion and convection play a role in carrying proteins to the interstitium. In those regions where transcapillary oncotic pressure gradients favor volume influx through the paracellular pathway in DVR, diffusion is the only means by which proteins can penetrate the interstitium. Whether the source of interstitial protein is DVR or ascending vasa recta depends on medullary depth, vasa recta permeability to proteins, and vasa recta reflection coefficients to small solutes and proteins. Finally, our model predicts significant axial protein gradients in the renal medullary interstitium.

Animals↗
PubMed2001

Benchmarking using simulated clinical scenarios: a feasibility project.

'Benchmarking' clinical practice and integrating such data with national guidelines offers a way of establishing standards for use in clinical governance. We report on a feasibility project for benchmarking clinical practice in one topic area (otitis media) using simulated clinical scenarios. Consistency and variations in clinical management were identified for different scenarios. Participants perceived the process likely to reflect actual practice and effect change in clinical management.

Acute Disease↗
PubMed2000

The renal medullary microcirculation.

Blood flow to the renal medulla is supplied through descending vasa recta (DVR), which are derived from the efferent arterioles of juxtamedullary glomeruli. In addition to their role as conduits for blood flow, it is accepted that the vasa recta are countercurrent exchangers. That process, however, involves events which are more complicated than paracellular diffusive exchange of NaCl and urea. Urea transport in DVR is accommodated through the combined expression of endothelial and erythrocyte facilitated carriers while transport of water involves solute driven efflux across water channels. Unlike DVR, which have a continuous endothelium, ascending vasa recta (AVR) are fenestrated with a very high hydraulic conductivity. Transport of water in AVR is probably governed by transmural hydraulic and oncotic pressure gradients. The parallel arrangement of DVR in outer medullary vascular bundles coupled with their capacity for vasomotion implies a role for regulation of the regional distribution of blood flow within the medulla The importance of the latter process in the urinary concentrating mechanism and the exchange of nutrients and O2 is poorly defined. The large number of hormones and autacoids that influence DVR vasomotion, however, suggests that DVR have evolved to optimize the functions of the renal medulla.

Animals↗
PubMed2000

Sexual origins of placental dysfunction.

Severe placental dysfunction is much more common in pregnancies with a male than with a female fetus. Furthermore, the birthweight/placental weight ratio is increased in these pregnancies, consistent with fetal growth restriction, and is higher with a male fetus than with a female fetus. These observations of placental insufficiency may underlie the increased in-utero loss rate of male fetuses.

Birth Weight↗