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Biomedical subjects

A Walker

Publications and source records attributed to A Walker.

At least 37 records · Page 2Linked to original sources
PubMed2004

A lysimeter experiment to investigate temporal changes in the availability of pesticide residues for leaching.

Leaching of three pesticides (isoproturon, chlorotoluron and triasulfuron) and a tracer (bromide) were determined in four contrasting soils ranging in texture from sandy loam to clay. The compounds were applied to undisturbed columns of soil and four columns for each soil were randomly selected and leached with 24-mm equivalent of water at prescribed time intervals (3, 9, 24, 37 and 57 d after application). A rapid decline in leached loads of isoproturon and chlorotoluron as time from application to irrigation increased was observed in all soils. In contrast, triasulfuron and bromide loads only decreased rapidly in the clay soil. Bromide losses decreased with decreasing clay contents of the soil and therefore with a decrease in structural development. Magnitudes of pesticide losses varied from soil to soil, depending on structural development and the organic carbon content. Pesticide degradation experiments on disturbed and undisturbed soil samples showed that the rapid decline of leached loads with time was faster than could be explained by degradation alone. Five physico-chemical processes are put forward to explain the different patterns of pesticide leached loads observed in the soils: (1) relative extent of preferential flow, (2) sorption capacity of the compounds to the different soils, (3) extent of degradation of the compounds in the soil, (4) variation in sorption kinetics between compounds associated with pesticide diffusion into soil aggregates, and (5) protection of the compounds by a combination of intra-aggregate diffusion and the presence of preferential flow pathways.

Diffusion↗
PubMed2004

Patient compliance in hypertension: role of illness perceptions and treatment beliefs.

Despite many years of study, questions remain about why patients do or do not take medicines and what can be done to change their behaviour. Hypertension is poorly controlled in the UK and poor compliance is one possible reason for this. Recent questionnaires based on the self-regulatory model have been successfully used to assess illness perceptions and beliefs about medicines. This study was designed to describe hypertensive patients' beliefs about their illness and medication using the self-regulatory model and investigate whether these beliefs influence compliance with antihypertensive medication. We recruited 514 patients from our secondary care population. These patients were asked to complete a questionnaire that included the Beliefs about Medicines and Illness Perception Questionnaires. A case note review was also undertaken. Analysis shows that patients who believe in the necessity of medication are more likely to be compliant (odds ratio (OR)) 3.06 (95% CI 1.74-5.38), P<0.001). Other important predictive factors in this population are age (OR 4.82 (2.85-8.15), P<0.001), emotional response to illness (OR 0.65 (0.47-0.90), P=0.01) and belief in personal ability to control illness (OR 0.59 (0.40-0.89), P=0.01). Beliefs about illness and about medicines are interconnected; aspects that are not directly related to compliance influence it indirectly. The self-regulatory model is useful in assessing patients health beliefs. Beliefs about specific medications and about hypertension are predictive of compliance. Information about health beliefs is important in achieving concordance and may be a target for intervention to improve compliance.

Adaptation, Psychological↗
PubMed2004

Regulation of granulocyte apoptosis by NF-kappaB.

Granulocyte apoptosis is a crucial part of the successful resolution of inflammation. In vitro results show that activation of NF-kappaB (nuclear factor kappaB) in granulocytes is a survival mechanism. NF-kappaB inhibitors increase the rate of constitutive apoptosis in neutrophils and eosinophils and cause these cells to respond to the pro-apoptotic effects of TNF-alpha (tumour necrosis factor-alpha). Results from both in vivo and in vitro experiments suggest that there are at least two important waves of NF-kappaB activation in inflammatory loci, which increase the expression of COX-2 (cyclooxygenase-2), itself an NF-kappaB controlled gene. The first wave causes the production of inflammatory mediators such as PGE2 (prostaglandin E2), allowing the establishment of inflammation. The second wave causes the synthesis of PGD2 and its metabolites that induce granulocyte apoptosis by inhibiting NF-kappaB activation. These metabolites may therefore be important physiological mediators controlling the resolution of inflammation. Although NF-kappaB is an important target for anti-inflammatory therapy, the timing of inhibition in vivo may be crucial, to ensure that production of PGD2 and its sequential metabolites can occur.

Animals↗
PubMed2004

Comparing performance between coronary intervention centres requires detailed case-mix adjusted analysis.

This study compares 12 month clinical outcomes and procedural costs at two interventional centres with significant differences in crude mortality and revascularization outcomes between 1997 and 1998. Percutaneous coronary intervention (PCI) registry data on 1046 consecutive patients treated contemporaneously at two university centres were linked to hospital discharge and death data to provide 12 month follow-up information on survival and repeat revascularization. Costs were determined by detailed analysis of equipment use, length of stay and staff from 100 contemporary cases at each centre to derive a procedural cost model. This model was then applied retrospectively to estimate cost per procedure. Stents were used more frequently at one centre (56 versus 26 per cent, chi(2) test, p < 0.001) resulting in greater procedural cost [mean (SE), pounds sterling 1970 (34) versus pounds sterling 1521 (39), t-test, p < 0.001). One year repeat target vessel PCI was significantly greater at the centre using more stents (10.3 versus 5.6 per cent, chi(2) test, p = 0.005) and the need for any repeat revascularization (PCI or coronary artery by-pass surgery) was also significantly greater at this centre (18.4 versus 10.8 per cent, chi(2) test, p < 0.001). Cox regression revealed that after correction for case-mix the difference in the need for repeat target vessel PCI between the two centres was no longer significant (p = 0.15). In the two centres studied, crude differences in cost per case, mortality and the need for revascularization were largely accounted for by significant differences in case-mix. Comparison of outcomes and costs between centres should not be published without careful adjustment for differences in case-mix.

Aged↗
PubMed2004

Ultrasound by emergency physicians to detect abdominal aortic aneurysms: a UK case series.

Early identification of abdominal aortic aneurysms in some patients can be difficult and the diagnosis is missed in up to 30% of patients. Ultrasound cannot be used to identify a leak, but the presence of an aneurysm in an unstable patient is conclusive. With minimal training emergency physicians can easily identify the aorta and thus in the early phase of resuscitation an aneurysm can be confidently excluded. The purpose of the examination is not to delineate the extent of the aneurysm, but to identify those patients that will need emergency surgery. A series of patients presented to the department in an unstable condition with equivocal abdominal signs. An ultrasound scan in the resuscitation room by members of the emergency department revealed an aneurysm, which was enough to convince the vascular surgeons to take the patient straight to theatre with good results. In patients who are stable, computed tomography will continue to be used to evaluate the extent of the aneurysm and identify a leak.

Aged↗
PubMed2004

Cost of an emerging epidemic: an economic analysis of atrial fibrillation in the UK.

OBJECTIVE: To evaluate the cost of atrial fibrillation (AF) to health and social services in the UK in 1995 and, based on epidemiological trends, to project this estimate to 2000. DESIGN, SETTING, AND MAIN OUTCOME MEASURES: Contemporary estimates of health care activity related to AF were applied to the whole population of the UK on an age and sex specific basis for the year 1995. The activities considered (and costs calculated) were hospital admissions, outpatient consultations, general practice consultations, and drug treatment (including the cost of monitoring anticoagulant treatment). By adjusting for the progressive aging of the British population and related increases in hospital admissions, the cost of AF was also projected to the year 2000. RESULTS: There were 534 000 people with AF in the UK during 1995. The "direct" cost of health care for these patients was 244 million pounds sterling (approximately 350 million euros) or 0.62% of total National Health Service (NHS) expenditure. Hospitalisations and drug prescriptions accounted for 50% and 20% of this expenditure, respectively. Long term nursing home care after hospital admission cost an additional 46.4 million pounds sterling (approximately 66 million euros). The direct cost of AF rose to 459 million pounds sterling (approximately 655 million euros) in 2000, equivalent to 0.97% of total NHS expenditure based on 1995 figures. Nursing home costs rose to 111 million pounds sterling (approximately 160 million euros). CONCLUSIONS: AF is an extremely costly public health problem.

Aged↗
PubMed2003

Randomized clinical trial comparing consultant-led or open access investigation for large bowel symptoms.

BACKGROUND: Referral of patients with large bowel symptoms is common and increasing. Currently most of these referrals are assessed at an outpatient clinic to determine the need and priority for investigation. METHODS: Over 21 months, 1131 patients referred by the general practitioner with large bowel symptoms were randomized. Patients in the consultant-led group were assessed by surgeons with a colorectal interest while those in the open access group underwent colonoscopy if they were 55 years or older and flexible sigmoidoscopy if younger. RESULTS: The most common symptom among referred patients was rectal bleeding (69.1 per cent) followed by change in bowel habit (48.8 per cent) and abdominal pain (32.3 per cent). There was a significant trend (P < 0.001) for patients in the consultant-led to have more investigations, and more patients in this group had no investigations (P < 0.001). Despite this, the percentage of patients with colonic or other pathology diagnosed was the same in both groups, 63.6 per cent in the consultant-led group compared with 61.8 per cent in the open access group (P = 0.558). Likewise the percentage of patients with cancer or other significant pathology was similar in both groups (13.9 versus 15.4 per cent; P = 0.532). The mean(s.d.) time to diagnose cancer or other significant pathology was 55.1(39.2) days in the consultant-led group compared with 57.4(33.6) days in the open access group (P = 0.514). The cost per patient was almost pound 105 more for patients in the consultant-led group. CONCLUSION: Patients referred by the general practitioner with large bowel symptoms should go directly to a properly managed and staffed open access large bowel investigation unit. This would enable most patients to have their investigations completed at one hospital attendance.

Ambulatory Care↗
PubMed2003

Clinical and cost effectiveness of surgery for morbid obesity: a systematic review and economic evaluation.

OBJECTIVE: To assess the clinical and cost effectiveness of surgery for people with morbid obesity. DESIGN: A systematic review of randomised control trials (RCTs), prospective clinical trials and economic evaluations identified from 14 electronic databases (including Medline, Cochrane library and Embase from their inception to October 2001), bibliographies and consultation with experts and manufacturers was performed to assess the clinical and cost effectiveness of different surgical procedures and nonsurgical management for morbid obesity. An economic evaluation was undertaken to assess cost effectiveness in the UK. SUBJECTS: People diagnosed as morbidly obese, defined as a body mass index (BMI) (weight in kilograms/height in metres(2)) >40 kg/m(2), or with a BMI>35 kg/m(2) with serious comorbid disease, in whom previous nonsurgical interventions had failed. MEASUREMENTS: The outcomes assessed included weight change, quality of life, peri- and postoperative morbidity and mortality, revision rates and obesity comorbidities. Cost effectiveness was modelled from these data and presented as cost per quality-adjusted life year (QALY). RESULTS: Included studies differed in methodological quality. Surgery resulted in a significantly greater loss of weight (23-37 kg more weight) than nonsurgical treatment, which was maintained to 8 years and led to improvements in quality of life and comorbidities. The economic evaluation of surgery compared with nonsurgical management suggested that surgery was cost effective at pound 11000 per QALY. Comparisons of the different types of surgery were equivocal. CONCLUSION: Surgery for morbid obesity appears to be clinically and cost effective. Because of the nature of the evidence, particularly the uncertainty in the clinical and economic evaluations, it is difficult to distinguish between the different surgical procedures.

Cost-Benefit Analysis↗
PubMed2003

Dental erosion -- changing prevalence? A review of British National childrens' surveys.

OBJECTIVES: To investigate the change in the prevalence of dental erosion, over time, by a review of the data from the published national dental surveys of young people in the UK. A subsidiary objective was to investigate the relationship between erosion and possible associated risk factors. DESIGN: The review was based on cross-sectional prevalence studies incorporating a clinical dental examination and structured interviews. SAMPLE: The data were collated from the 1993 UK childrens' dental health survey and the dental report of the two National Diet and Nutrition Surveys (NDNS) of children aged 1(1/2)-4(1/2) in 1992/3 and 4-18 years in 1996/7. The criteria used for data collection were comparable between the three different studies. RESULTS: Comparing the data from the different studies, the prevalence of erosion was seen to increase from the time of the childrens' dental health survey in 1993 and the NDNS study of 4-18-year-olds in 1996/7. There was a trend towards a higher prevalence of erosion in children aged between 3(1/2) and 4(1/2) and in those who consumed carbonated drinks on most days compared with toddlers consuming these drinks less often. Drinks overnight were associated with an increased prevalence of erosion. More 4-6-year-olds with reported symptoms of gastro-oesophageal reflux had erosion compared with symptom-free children. On multivariate analysis, the strongest independent association with erosion was geography, with children living in the North having twice the odds of having erosion compared with those in London and the South-east. CONCLUSIONS: Comparing prevalence data from cross-sectional national studies indicates that dental erosion increases between different age cohorts of young people over time. Dietary associations with erosion are present but weak. Similarly, there is an association apparent between erosion, symptoms of gastro-oesophageal reflux and socio-demographic variables such as region of domicile, social class, and receipt of social benefits.

Adolescent↗
PubMed2003

Acute panuveitis and Takayasu's arteritis.

A 12 year old boy presented with severe hypertension and was diagnosed with renal artery stenosis requiring balloon angioplasty. Takayasu's arteritis was subsequently diagnosed, but he also developed acute panuveitis, an entity not previously reported in a child with this condition.

Acute Disease↗
PubMed2003

Barking up the wrong tree? A survey of dog bite wound management.

OBJECTIVES: Several trials have been published examining the role of antibiotics in dog bite wound management. A meta-analysis of these suggests that there is very little benefit to routine antibiotic prescription in these patients. All papers however incorporated rigorous wound care regimens involving large volume irrigation. METHODS: The authors undertook a telephone survey to investigate wound care and prescribing practice in bite wound management in accident and emergency and minor injury units in the Yorkshire region. RESULTS: Twenty one departments were contacted. Only 10% of departments routinely irrigate these wounds. Antibiotics are prescribed routinely in 71%. CONCLUSIONS: Management of dog bite wounds would not seem to be evidence based in most departments in this sample.

Animals↗
PubMed2003

The current cost of angina pectoris to the National Health Service in the UK.

OBJECTIVE: To calculate the cost of angina pectoris to the UK National Health Service (NHS) in the year 2000. METHODS: Calculation of the cost of hospital admissions, revascularisation procedures, hospital outpatient consultations, general practice (GP) consultations, and prescribed drug treatment. RESULTS: 634 000 individuals (1.1% of the UK population) consulted GPs 2.35 million times, costing pound 60.5 million. They required 16.0 million prescriptions (cost pound 80.7 million) and 254 000 hospital outpatient referrals (cost pound 30.4 million). There were 149 000 hospital admissions, 117 000 coronary angiograms, 21 400 coronary artery bypass operations, 17 700 percutaneous coronary interventions, and 516 000 outpatient visits, at a cost of pound 208.4 million, pound 69.9 million, pound 106.2 million, pound 60.7 million, and pound 52.2 million, respectively. The direct cost of angina was therefore pound 669 million (1.3% of total NHS expenditure), with hospital bed occupancy and procedures accounting for 32% and 35% of this total, respectively. CONCLUSIONS: Angina is a common and costly public health problem. It consumed over 1% of all NHS expenditure in the year 2000, mainly because of hospital bed occupancy and revascularisation procedures. This is likely to be a conservative estimate of its true cost.

Ambulatory Care↗
PubMed2003

From trench fever to endocarditis.

The case of a 44 year old woman with infective endocarditis due to Bartonella quintana, an organism long recognised to cause a condition known as trench fever, is reported. This case illustrates the lengthy differential diagnosis of "culture negative" endocarditis. In addition the presence of serological cross reactivity of Bartonella spp and Chlamydia spp demonstrates the potential for misdiagnosis in these circumstances.

Adult↗
PubMed2003

Regulation of granulocyte apoptosis by hemopoietic growth factors, cytokines and drugs: potential relevance to allergic inflammation.

It has become apparent that the resolution of inflammation depends on the removal of unwanted inflammatory cells, a process governed by physiological apoptosis and non-inflammatory clearance of apoptotic cells. Granulocytes are central to many of the pathophysiological consequences of uncontrolled inflammatory reactions. Hemopoietic factors and cytokines play a critical role in regulating the longevity of these cells in vitro and in vivo. Here we review the progress that has been made in the understanding of granulocyte apoptosis and the implications for immunotherapy and pharmacological strategies in the treatment of allergic inflammatory diseases for therapeutic gain.

Animals↗
PubMed2003

Time and dose-dependent modulation of phase 1 and phase 2 gene expression in response to treatment of MCF-7 cells with a natural anti-cancer agent.

Several known anti-cancer agents have been shown to lead to increased expression of phase 2 metabolic enzymes without affecting phase 1 enzymes. Phase 1 cytochrome P450 (CYP) enzymes are relevant in cancer studies in that they are involved in oxidative metabolism, biotransformation and detoxification, whereas phase 2 enzyme catalysis leads to clearance. In this study, we obtained semi-quantitative measurements of cytochrome P450 (phase 1) and phase 2 microsomal epoxide hydrolase (mEH) gene expression levels in response to treatment of MCF-7 breast cancer cells with water-soluble Vernonia amygdalina (V.A.) extract. V.A., a vegetable grown in Nigeria, has potential as an anti-cancer agent. The results of Western blot and RT-PCR analyses show that V.A. extract acts as a monofunctional inducer within exposure times ranging from 2-16 hr and dose ranges from 3-100 microg/ml of V.A. Exposure of cells to low doses of V.A. did not affect expression levels of CYP1A1/1A2 mRNA, but lead to induction of mEH, thus supporting the chemotherapeutic potential of VA. However, in parallel studies, CYP3A4 gene expression was also induced, suggesting potential intermediates which influence drug-drug interactions. These data are useful toward further validating V.A. extract as a potential clinically useful natural anti-cancer agent and provide some support for the concept that modulation in CYP3A4 expression in response to treatment is relevant to prognosis.

Breast Neoplasms↗