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Biomedical subjects

C P Bradley

Publications and source records attributed to C P Bradley.

At least 19 recordsLinked to original sources
PubMed2005

Targeted nNOS gene transfer into the cardiac vagus rapidly increases parasympathetic function in the pig.

Nitric oxide (NO) derived from neuronal nitric oxide synthase (nNOS) facilitates cardiac vagal neurotransmission and bradycardia in vitro. Here we provide evidence of rapid (within 9 h) protein expression and increased vagal responsiveness in vivo following targeted gene transfer of nNOS into the cardiac vagus of the pig. Right vagi were injected with vector encoding nNOS (Ad.nNOS) or saline, while left vagi received an injection of vector encoding enhanced green fluorescent protein (Ad.eGFP). Enhanced nNOS protein expression was detected exclusively in the right vagus nerve, with no evidence of iNOS expression. This was associated with increased baroreflex sensitivity and greater heart rate responsiveness to right vagal stimulation. In contrast, responsiveness of left vagi, or sham-injected right vagi remained constant over the same time period. Basal heart rate was unchanged following gene transfer, suggesting no change in vagal tone. These results support the pre-/post-ganglionic synapse as a site for NO-mediated facilitation of vagal bradycardia in the pig. In addition they demonstrate in vivo that functional gene expression induced with adenoviral vectors occurs earlier than first thought, and may therefore, provide a novel intervention to acutely modulate the neural control of cardiac excitability.

Animals↗
PubMed2001

Prescribing new drugs: qualitative study of influences on consultants and general practitioners.

OBJECTIVE: To explore consultants' and general practitioners' perceptions of the factors that influence their decisions to introduce new drugs into their clinical practice. DESIGN: Qualitative study using semistructured interviews. Monitoring of hospital and general practice prescribing data for eight new drugs. SETTING: Teaching hospital and nearby general hospital plus general practices in Birmingham. PARTICIPANTS: 38 consultants and 56 general practitioners who regularly referred to the teaching hospital. MAIN OUTCOME MEASURES: Reasons for prescribing a new drug; sources of information used for new drugs; extent of contact between consultants and general practitioners; and amount of study drugs used in hospitals and by general practitioners. RESULTS: Consultants usually prescribed new drugs only in their specialty, used few new drugs, and used scientific evidence to inform their decisions. General practitioners generally prescribed more new drugs and for a wider range of conditions, but their approach varied considerably both between general practitioners and between drugs for the same general practitioner. Drug company representatives were an important source of information for general practitioners. Prescribing data were consistent with statements made by respondents. CONCLUSIONS: The factors influencing the introduction of new drugs, particularly in primary care, are more multiple and complex than suggested by early theories of drug innovation. Early experience of using a new drug seems to strongly influence future use.

Drug Industry↗
PubMed2001

Giving voice to the lifeworld. More humane, more effective medical care? A qualitative study of doctor-patient communication in general practice.

Mishler (The discourse of medicine. The dialectics of medical interviews. Norwood, NJ: Ablex), applying Habermas's theory of Communicative Action to medical encounters. showed how the struggle between the voice of medicine and the voice of the lifeworld fragmented and suppressed patients' multi-faceted, contextualised and meaningful accounts. This paper investigates and critiques Mishler's premise that this results in inhumane, ineffective medical care. Using a more complex data collection strategy, comprising patient interviews, doctor interviews and transcribed consultations we show more complex relations than emerged from Mishler's analysis. We found four communication patterns across 35 general practice case studies. When doctor and patient both used the voice of medicine exclusively (acute physical complaints) this worked for simple unitary problems (Strictly Medicine). When both doctor and patient engaged with the lifeworld, more of the agenda was voiced (Mutual Lifeworld) and patients were recognised as unique human beings (psychological plus physical problems). Poorest outcomes occurred where patients used the voice of the lifeworld but were ignored (Lifeworld Ignored) or blocked (Lifeworld Blocked) by doctors' use of voice of medicine (chronic physical complaints). The analysis supports the premise that increased use of the lifeworld makes for better outcomes and more humane treatment of patients as unique human beings. Some doctors switched communication strategies in different consultations, which suggests that their behaviour might be open to change. If doctors could be sensitised to the importance of dealing with the concerns of the lifeworld for patients with chronic physical conditions as well as psychological conditions, it might be possible to obtain better care for patients. This would require attention to structural aspects of the healthcare system to enable doctors to work fully within the patient-centred model.

Adult↗
PubMed2001

Proton pump inhibitors: a study of GPs' prescribing.

BACKGROUND: There has been a rapid increase in proton pump inhibitor (PPI) prescribing in recent years, and controlling the cost and improving the quality of prescribing is an issue of concern to many GPS: OBJECTIVE: Our aim was to compare GPs' usage of different PPIs and explore how GPs' PPI prescribing changes following the introduction of a cheaper competitor. METHODS: PPI prescribing data (PACT) for 53 GPs, who were selected as regular users of a teaching hospital, were monitored from January 1995 to December 1997. The GPs were located in two adjoining health districts and had been interviewed about influences on their decisions to begin prescribing lansoprazole. The PPI prescribing data were collected for the teaching hospital and the general hospital in the adjoining district. RESULTS: Complete prescribing data were available for 50 GPS: Total PPI prescribing increased throughout the study due mainly to increasing use of the new PPIS: Use of the new PPIs increased from 6 to 24% over 3 years. The proportion of maintenance doses prescribed increased from 3 to 12%. There was a 23-fold difference in total PPI prescribing and an 87-fold difference in lansoprazole prescribing between the highest and lowest prescribers. The uptake of pantoprazole was slower than that of lansoprazole. A rapid increase in the use of lansoprazole by the GPs followed an increase in use in the teaching hospital. CONCLUSION: Hospital prescribing was an important influence on the choice of PPI used by GPS: The wide variation in PPI prescribing suggests that there is scope for improvement in the quality and cost of PPI prescribing.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2001

The computational performance of a high-order coupled FEM/BEM procedure in electropotential problems.

This paper presents a thorough analysis of the computational performance of a coupled cubic Hermite boundary element/finite element procedure. This C1 (i.e., value and derivative continous) method has been developed specifically for electropotential problems, and has been previously applied to torso and skull problems. Here, the behavior of this new procedure is quantified by solving a number of dipole in spheres problems. A detailed set of results generated with a wide range of the various input parameters (such as dipole orientation, location, conductivity, and solution method used in each spherical shell [either finite element or boundary elements]) is presented. The new cubic Hermite boundary element procedure shows significantly better accuracy and convergence properties and a significant reduction in CPU time than a traditional boundary element procedure which uses linear or constant elements. Results using the high-order method are also compared with other computational methods which have had quantitative results published for electropotential problems. In all cases, the high-order method offered a significant improvement in computational efficiency by increasing the solution accuracy for the same, or fewer, solution degrees of freedom.

Biomedical Engineering↗
PubMed2001

Noninvasive electrical imaging of the heart: theory and model development.

The aim of this work is to begin quantifying the performance of a recently developed activation imaging algorithm of Huiskamp and Greensite [IEEE Trans. Biomed. Eng. 44:433-446]. We present here the modeling and computational issues associated with this process. First, we present a practical construction of the appropriate transfer matrix relating an activation sequence to body surface potentials from a general boundary value problem point of view. This approach makes explicit the role of different Green's functions and elucidates features (such as the anisotropic versus isotropic distinction) not readily apparent from alternative formulations. A new analytic solution is then developed to test the numerical implementation associated with the transfer matrix formulation presented here and convergence results for both potentials and normal currents are given. Next, details of the construction of a generic porcine model using a nontraditional data-fitting procedure are presented. The computational performance of this model is carefully examined to obtain a mesh of an appropriate resolution to use in inverse calculations. Finally, as a test of the entire approach, we illustrate the activation inverse procedure by reconstructing a known activation sequence from simulated data. For the example presented, which involved two ectopic focii with large amounts of Gaussian noise (100 microV rms) present in the torso signals, the reconstructed activation sequence had a similarity index of 0.880 when compared to the input source.

Algorithms↗
PubMed2000

Patients' unvoiced agendas in general practice consultations: qualitative study.

OBJECTIVE: To investigate patients' agendas before consultation and to assess which aspects of agendas are voiced in the consultation and the effects of unvoiced agendas on outcomes. DESIGN: Qualitative study. SETTING: 20 general practices in south east England and the West Midlands. PARTICIPANTS: 35 patients consulting 20 general practitioners in appointment and emergency surgeries. RESULTS: Patients' agendas are complex and multifarious. Only four of 35 patients voiced all their agendas in consultation. Agenda items most commonly voiced were symptoms and requests for diagnoses and prescriptions. The most common unvoiced agenda items were: worries about possible diagnosis and what the future holds; patients' ideas about what is wrong; side effects; not wanting a prescription; and information relating to social context. Agenda items that were not raised in the consultation often led to specific problem outcomes (for example, major misunderstandings), unwanted prescriptions, non-use of prescriptions, and non-adherence to treatment. In all of the 14 consultations with problem outcomes at least one of the problems was related to an unvoiced agenda item. CONCLUSION: Patients have many needs and when these are not voiced they can not be addressed. Some of the poor outcomes in the case studies were related to unvoiced agenda items. This suggests that when patients and their needs are more fully articulated in the consultation better health care may be effected. Steps should be taken in both daily clinical practice and research to encourage the voicing of patients' agendas.

Adult↗
PubMed2000

Misunderstandings in prescribing decisions in general practice: qualitative study.

OBJECTIVES: To identify and describe misunderstandings between patients and doctors associated with prescribing decisions in general practice. DESIGN: Qualitative study. SETTING: 20 general practices in the West Midlands and south east England. PARTICIPANTS: 20 general practitioners and 35 consulting patients. MAIN OUTCOME MEASURES: Misunderstandings between patients and doctors that have potential or actual adverse consequences for taking medicine. RESULTS: 14 categories of misunderstanding were identified relating to patient information unknown to the doctor, doctor information unknown to the patient, conflicting information, disagreement about attribution of side effects, failure of communication about doctor's decision, and relationship factors. All the misunderstandings were associated with lack of patients' participation in the consultation in terms of the voicing of expectations and preferences or the voicing of responses to doctors' decisions and actions. They were all associated with potential or actual adverse outcomes such as non-adherence to treatment. Many were based on inaccurate guesses and assumptions. In particular doctors seemed unaware of the relevance of patients' ideas about medicines for successful prescribing. CONCLUSIONS: Patients' participation in the consultation and the adverse consequences of lack of participation are important. The authors are developing an educational intervention that builds on these findings.

Adult↗
PubMed2000

Doctor-patient communication about drugs: the evidence for shared decision making.

The traditional paternalistic model of medical decision-making, in which doctors make decisions on behalf of their patients, has increasingly come to be seen as outdated. Moreover, the role of the patient in the consultation has been emphasised, notably through the adoption of 'patient-centred' strategies. Models that promote patients' active involvement in the decision-making process about treatment have been developed. We examine one particular model of shared decision making [Charles, C., Gafni, A., Whelan, T, 1997. Shared decision-making in the medical encounter: what does it mean? (or it takes at least two to tango). Social Science & Medicine 44, 681-692.]. The model has four main characteristics. These are that (1) both the patient and the doctor are involved, (2) both parties share information, (3) both parties take steps to build a consensus about the preferred treatment and (4) an agreement is reached on the treatment to implement. Focusing on the first two of the four characteristics of the model, we use the findings from a study of 62 consultations, together with interviews conducted with patients and general practitioners, to consider participation in the consultation in terms of sharing information about, and views of, medicines. We found little evidence that doctors and patients both participate in the consultation in this way. As a consequence there was no basis upon which to build a consensus about the preferred treatment and reach an agreement on which treatment to implement. Thus even the first two of the four conditions said to be necessary for shared decision making were not generally present in the consultations we studied. These findings were presented in feedback sessions with participating GPs, who identified a number of barriers to shared decision making, as well as expressing an interest in developing strategies to overcome these barriers.

Decision Making↗
PubMed2000

Effects of material properties and geometry on electrocardiographic forward simulations.

This paper investigates the effect on torso potentials of changes in the material properties of the torso volume conductor and changes in the relative geometry of the heart and torso. The investigations are performed using a number of forward simulations with a high-order coupled finite element/boundary element torso model. This torso model contains descriptions of the epicardium, lungs, skeletal muscle (with a continuously varying fiber field) and subcutaneous fat. The number of nodes, elements and solution degrees-of-freedom used in the computational torso model are considerably smaller than previous torso models of similar complexity. The successful forward simulations in this paper hence demonstrate the use of the high-order coupled approach with realistic problems. The results of the torso simulations show that the torso inhomogeneities do affect the torso potentials but do not affect the distribution or pattern of the torso potentials. The inhomogeneities considered are found to have a varying, but important, effect on the torso potentials. The effect of the subcutaneous fat is found to be more important and the effect of the skeletal muscle is found to be less important than previous reports in the literature. The results also show that the relative geometry of the heart and torso is very important in determining the torso potential magnitudes and distributions.

Abdomen↗
PubMed1999

GPs' perceptions of patient influence on prescribing.

BACKGROUND: Controlling prescribing costs is an issue of concern to many GPs. OBJECTIVE AND METHODS: This paper is based on interviews with 21 GPs in which they were asked about influences on prescribing budgets. RESULTS: The results presented relate specifically to GPs' perceptions of the influence of patients on prescribing. Perceptions of patient demand were described both in terms of a general demand and demand by patients with specific health beliefs or particular social characteristics. Generally, GPs reported that decisions to prescribe were informed by a concern to maintain a good relationship with their patients, and not to risk the relationship by not prescribing when they believed a prescription was expected. CONCLUSIONS: Although information was available about whether practices had a 'high' or 'low' budget, and whether they were under- or overspent, there did not appear to be any relationship between GPs' beliefs that patient expectations affected their prescribing and whether they were under or over budget. This paper suggests that patient demand for prescriptions may not only be overestimated but also perpetuated by GPs' belief in its existence and a wish to maintain a good doctor-patient relationship.

Attitude of Health Personnel↗
PubMed1998

Patient attitudes to over-the-counter drugs and possible professional responses to self-medication.

BACKGROUND: There is a paucity of research about patients' attitudes towards their doctor's recommending over-the-counter (OTC) remedies or about how patients respond to the doctor's suggestion to try an OTC remedy. OBJECTIVES: The aim of this study was to ascertain the attitudes of patients to OTC drugs. METHODS: 505 consecutive patients from each of six participating practices filled in a questionnaire. RESULTS: A total of 2765 (91.3%) patients responded. The responses from 2624 patients were from adults and are presented here. Based on the number of valid responses to each question, 53.8% of these patients were exempt from prescription charges, 55.1% took regular prescribed medication and 24.6% stated that they used OTC remedies regularly. There were generally positive attitudes to doctors enquiring about prior OTC use as well as to doctors making OTC recommendations in the consultation. However, patients expressed fairly negative attitudes towards pharmacists making generic substitutions and were even more hostile to the idea that pharmacists should make therapeutic substitutions. CONCLUSION: In conclusion, GPs should consider asking their patients regularly about their use of OTC medicines and also consider recommending OTC use if this is cheaper than FP10s. However, the public at present do not appear to be prepared for interventions by the pharmacist.

Adolescent↗
PubMed1997

Primary care--opportunities and threats. Developing prescribing in primary care.

The latest white papers on the NHS focus on stimulating innovation in the delivery of primary care and removing barriers to further development. Some of this innovation relates directly to prescribing in primary care, and in this article the authors speculate on what might happen if the prescribing initiatives referred to in the white papers were extended and disseminated more widely. The initiatives which might have the biggest impact are those encouraging closer collaboration between general practitioners and community pharmacists and those aiding extension of the current nurse prescribing scheme in primary care. Both offer considerable opportunities to improve primary care, but both bear some potential risks.

Drug Utilization↗