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Biomedical subjects

R Watt

Publications and source records attributed to R Watt.

At least 19 recordsLinked to original sources
PubMed2004

The facilitating factors and barriers influencing change in dental practice in a sample of English general dental practitioners.

AIM: The objective of this study was to investigate the barriers and facilitators to change in dental practices among a sample of general dental practitioners (GDPs) from three regions of England. METHOD: In-depth face-to-face interviews with 60 GDPs were undertaken. The sample was selected from a group of 317 GDPs who had completed a questionnaire in the first phase of this study. The participants were selected to reflect diversity regarding the number and extent of self-reported changes reported in the questionnaire, and personal and practice characteristics. Of the 92 attempted contacts, 60 (65%) of the interviews were successfully completed. The interview schedule formed the basis of the interview. All the interviews and notes were transferred on to NUD*IST QSR version 4, a qualitative analysis package. RESULTS: No single factor was identified as being more important than another in facilitating change. The main facilitators for change were: financial factors, regular patient attendance, particularly a core patient group, staff loyalty, having regular staff meetings and open communication and having access to peer support. The main barriers to change were the reverse of the facilitators plus not having a financial stakehold in the practice. CONCLUSIONS: A range of factors were identified as influencing change in general dental practice. These include GDPs' attitudes and experience of change, patient factors, organisational issues, contact with peers and access to appropriate training courses.

Adult↗
PubMed2004

The prevalence and nature of recent self-reported changes in general dental practice in a sample of English general dental practitioners.

OBJECTIVE: To determine the extent and types of change in seven domains of dental practice in a sample of English general dental practitioners (GDPs). METHODS: A postal questionnaire was sent to 561 GDPs on the dental lists of three health authorities in diverse regions of England. Information collected included demographic details on personal and practice characteristics, self-rating of amount of change in the seven domains of practice and factors influencing change. RESULTS: The response rate was 60%. Fifty-six per cent of the sample were under 40 years old. Over a third of respondents reported "changing a lot or completely" certain clinical activities, practice management arrangements and practice amenities. The highest self-reported level of change was in clinical activities. Of the GDPs who reported changing their clinical activities, 56% reported an increase in preventive care, followed by crown and bridge (44%), periodontics (44%) and endodontics (43%). Practice management rated second in the mean rank scores for self-reported change. The main changes reported were the introduction of computer systems and employment of practice managers. A sizeable percentage (66%) reported increasing the amount of information they provided to patients and the time spent discussing care. Quality assurance activities were the area of practice least likely to have changed over a 5-year period. Over half the sample reported not being involved in any quality assurance activities in the previous 5 years. Those respondents who were younger, had a postgraduate qualification and earned more than 20% of their income from private practice reported higher levels of change. CONCLUSIONS: General dental practitioners' work patterns are dynamic and appear to be responding to changing needs and demands on their service. The main changes were in the types of clinical procedures being carried out. The low prevalence of changes reported in auditing and peer review activities needs to be investigated further.

Adult↗
PubMed2001

Icodextrin as salvage therapy in peritoneal dialysis patients with refractory fluid overload.

BACKGROUND: Icodextrin is a high molecular weight, starch-derived glucose polymer, which is capable of inducing sustained ultrafiltration over prolonged (12-16 hour) peritoneal dialysis (PD) dwells. The aim of this study was to evaluate the ability of icodextrin to alleviate refractory, symptomatic fluid overload and prolong technique survival in PD patients. METHODS: A prospective, open-label, pre-test/post-test study was conducted in 17 PD patients (8 females/9 males, mean age 56.8 +/- 2.9 years) who were on the verge of being transferred to haemodialysis because of symptomatic fluid retention that was refractory to fluid restriction, loop diuretic therapy, hypertonic glucose exchanges and dwell time optimisation. One icodextrin exchange (2.5 L 7.5%, 12-hour dwell) was substituted for a long-dwell glucose exchange each day. RESULTS: Icodextrin significantly increased peritoneal ultrafiltration (885 +/- 210 ml to 1454 +/- 215 ml, p < 0.05) and reduced mean arterial pressure (106 +/- 4 to 96 +/- 4 mmHg, p < 0.05), but did not affect weight, plasma albumin concentration, haemoglobin levels or dialysate:plasma creatinine ratio. Diabetic patients (n = 12) also experienced improved glycaemic control (haemoglobin Alc decreased from 8.9 +/- 0.7% to 7.9 +/- 0.7%, p < 0.05). Overall PD technique survival was prolonged by a mean of 11.6 months (95% CI 6.0-17.3 months). On multivariate Cox proportional hazards analysis, extension of technique survival by icodextrin was only significantly predicted by baseline net daily peritoneal ultrafiltration (adjusted HR 2.52, 95% CI 1.13-5.62, p < 0.05). CONCLUSIONS: Icodextrin significantly improved peritoneal ultrafiltration and extended technique survival in PD patients with symptomatic fluid overload, especially those who had substantially impaired peritoneal ultrafiltration.

Dialysis Solutions↗
PubMed2001

Evidence-based dentistry: an overview of the challenges in changing professional practice.

A great deal of effort and resources are currently being directed at developing an evidence-based approach to healthcare delivery. The success of the evidence-based movement will depend upon the provision of necessary support to help GDPs achieve change. This paper aims to give an overview of current knowledge on what types of interventions are most effective at changing health professionals' clinical practices. Barriers to change are highlighted and the implications for the development of evidence-based dentistry are considered. Further research on organisational, social and personal influences affecting the application of evidence-based practice is necessary.

Attitude of Health Personnel↗
PubMed2001

Oral health promotion evaluation--time for development.

Increasing emphasis is now being placed upon the evaluation of health service interventions to demonstrate their effects. A series of effectiveness reviews of the oral health education and promotion literature has demonstrated that many of these interventions are poorly and inadequately evaluated. It is therefore difficult to determine the effectiveness of many interventions. Based upon developments from the field of health promotion research this paper explores options for improving the quality of oral health promotion evaluation. It is essential that the methods and measures used in the evaluation of oral health promotion are appropriate to the intervention. For many oral health promotion interventions clinical measures and methods of evaluation may not be appropriate. This paper outlines an evaluation framework which can be used to assess the range of effects of oral health promotion programmes. Improving the quality of oral health promotion evaluation is a shared responsibility between researchers and those involved in the provision of programmes. The provision of adequate resources and training are essential requirements for this to be successfully achieved.

Health Education, Dental↗
PubMed1999

Photoassembly of the manganese cluster and oxygen evolution from monomeric and dimeric CP47 reaction center photosystem II complexes.

Isolated subcomplexes of photosystem II from spinach (CP47RC), composed of D1, D2, cytochrome b(559), CP47, and a number of hydrophobic small subunits but devoid of CP43 and the extrinsic proteins of the oxygen-evolving complex, were shown to reconstitute the Mn(4)Ca(1)Cl(x) cluster of the water-splitting system and to evolve oxygen. The photoactivation process in CP47RC dimers proceeds by the same two-step mechanism as observed in PSII membranes and exhibits the same stoichiometry for Mn(2+), but with a 10-fold lower affinity for Ca(2+) and an increased susceptibility to photodamage. After the lower Ca(2+) affinity and the 10-fold smaller absorption cross-section for photons in CP47 dimers is taken into account, the intrinsic rate constant for the rate-limiting calcium-dependent dark step is indistinguishable for the two systems. The monomeric form of CP47RC also showed capacity to photoactivate and catalyze water oxidation, but with lower activity than the dimeric form and increased susceptibility to photodamage. After optimization of the various parameters affecting the photoactivation process in dimeric CP47RC subcores, 18% of the complexes were functionally reconstituted and the quantum efficiency for oxygen production by reactivated centers approached 96% of that observed for reconstituted photosystem II-enriched membranes.

Dimerization↗
PubMed1999

An alarming lack of public awareness towards oral cancer.

OBJECTIVE: To determine public awareness and knowledge of oral cancer in Great Britain. DESIGN: The respondents were selected according to a systematic probability sample designed to be representative of all adults in Great Britain (GB). The overall design was similar to previous omnibus surveys carried out by National Opinion Poll (NOP). The survey was carried out in ten regions of GB in September 1995 and was commissioned by the Health Education Authority (HEA). SUBJECTS AND METHODS: A random sample of 1,894 members of the public over the age of 16 years were asked in face-to-face interviews their knowledge relating to cancer, with particular reference to oral cancer, its causes and those at high risk and general attitudes to cancer. RESULTS: Oral cancer was one of the least heard of cancers by the public with only 56% of the participants being aware, whereas 96% had heard of skin cancer, 97% lung cancer and 86% cervical cancer. There was a 76% awareness of the link between smoking and oral cancer but only 19% were aware of its association with alcohol misuse. Whereas 94% agreed that early detection can improve the treatment outcome, a disheartening 43% believed that whether a person developed a cancer or not was a matter of chance and therefore was unavoidable. CONCLUSIONS: This survey highlights a general lack of awareness among the public about mouth cancer and a lack of knowledge about its causation especially the excess risk associated with alcohol. RECOMMENDATIONS: There is a clear need to inform and educate the public in matters relating to the known risk factors associated with oral cancer. A media campaign informing the public about oral cancer is clearly required. The need for the reduction in the incidence of oral cancer should be included in 'Our healthier nation' targets. An overall health promotion strategy to reduce cancers should include oral cancer as a priority. In addition the European Code against Cancer which aims to improve prevention, the early detection of oral cancer and the necessity for fast track referral should be made more widely known. Recognition of oral cancer in local strategies for oral health should be encouraged.

Adolescent↗
PubMed1999

Inequalities in oral health: a review of the evidence and recommendations for action.

Reducing inequalities in health has become one of the main health policy issues in the late 1990s. The Labour Government set up an independent inquiry into inequalities in health under Sir Donald Acheson to make recommendations on approaches to reducing health inequalities. This paper reviews the evidence on inequalities in oral health in Britain. Dramatic improvements in dental health in children and young adults have taken place in the past 30 years. The levels of caries in permanent teeth of children is low. Widening inequalities in oral health however exist between social classes, regions of England, and among certain minority ethnic groups in pre-school children. The main social class and minority ethnic differences in dental caries is in pre-school children. Wide district and regional differences also exist in prevalence of caries in young children. The area differences relate very strongly to deprivation. In adults the differences in decay experience is less unequal than in children but there are marked social class inequalities in edentulousness. Dental caries decreased in all social classes in the United Kingdom. The main causes of the inequalities are differences in patterns of consumption of non milk extrinsic sugars and fluoridated toothpaste. Improvements in oral health that have occurred over the last 30 years have been largely a result of fluoride toothpaste and social, economic and environmental factors. Oral health inequalities will only be reduced through the implementation of effective and appropriate oral health promotion policy. Treatment services will never successfully tackle the underlying cause of oral diseases.

Adult↗
PubMed1997

UBI4, the polyubiquitin gene of Saccharomyces cerevisiae, is a heat shock gene that is also subject to catabolite derepression control.

Carbon and nitrogen regulation of UBI4, the stress-inducible polyubiquitin gene of Saccharomyces cerevisiae, was investigated using a UBI4 promoter-LacZ fusion gene (UBI4-LacZ). Expression of this gene in cells grown on different media indicated that the UBI4 promoter is more active during growth on respiratory than on fermentable carbon sources but is not subject to appreciable control by nitrogen catabolite repression. UBI4-LacZ expression was virtually identical in cells having constitutively high (ras2, sra1-13) or constitutively low (ras2) levels of cyclic AMP-dependent protein kinase activity, indicating that this kinase does not exert a major influence on UBI4 expression. Catabolite derepression control of the UBI4 promoter was confirmed by measurements of UBI4-LacZ expression in hap mutant and wild-type strains before and after transfer from glucose to lactate. Mutagenesis of the perfect consensus for HAP2/3/4 complex binding at position -542 resulted in considerable reduction of UBI4 promoter derepression with respiratory adaptation in HAP wild-type cells and abolished the reduced UBI4-LacZ derepression normally seen when aerobic cultures of the hap1 mutant are transferred from glucose to lactate. This HAP2/3/4 binding site is therefore a major element contributing to catabolite derepression of the UBI4 promoter, although data obtained with hapl mutant cells indicated that HAP1 also contributes to this derepression. The HAP2/3/4 and HAP1 systems are normally found to activate genes for mitochondrial (respiratory) functions. Their involvement in mediating higher activity of the UBI4 promoter during respiratory growth may reflect the contribution of UBI4 expression to tolerance of oxidative stress.

Biopolymers↗
PubMed1994

Polyubiquitin gene expression contributes to oxidative stress resistance in respiratory yeast (Saccharomyces cerevisiae).

UBI4, the polyubiquitin gene of Saccharomyces cerevisiae, is expressed at a low level in vegetative cells, yet induced strongly in response to starvation, cadmium, DNA-damaging agents and heat shock. UBI4 is also expressed at a higher basal level in cells growing by respiration as compared to glucose-repressed cells growing by fermentation. This higher UBI4 expression of respiratory cultures probably helps to counteract the greater oxidative stress of respiratory growth. The effects of inactivating UBI4 on high temperature viability are more marked with respiratory cultures. Also loss of UBI4 leads to a considerably increased rate of killing of respiring cells by hydrogen peroxide, whereas the same gene inactivation has relatively little effect on the peroxide sensitivity of cells in which mitochondrial functions are repressed. This is the first study to reveal that ubiquitin levels in cells can influence their ability to withstand oxidative stress.

Biopolymers↗
PubMed1994

A computational examination of image segmentation and the initial stages of human vision.

A novel approach to the question of image segmentation is considered. Instead of relying on edge-detection mechanisms to encircle the image of an object, it is proposed that the general Gestalt-like properties of images of objects can be used. These manifest themselves as particularly simple properties at relatively coarse spatial scales when the image is filtered with orientation-selective filters. The first part of the paper is concerned with a computational analysis of this proposal. A key issue is the question of how the information in filtered images is extracted. A simple primitive parametric description of zero-bounded blobs is used in this paper. It is shown how such a scheme can support readily the clustering of features with Gestalt-like properties. In the second part of the paper, two general difficulties for vision that are particularly severe for the present scheme are considered. The first of these are the effects of strongly asymmetric illumination. The second are the effects of using a cluttered scene. In each case the nature of the problem is examined and the nature of the computational solution considered.

Contrast Sensitivity↗
PubMed1991

Seeing texture.

Explore the source record for details and available documents.

Journal Article↗
PubMed1991

Removal of lymphocytotoxic antibodies by pretransplant immunoadsorption therapy in highly sensitized renal transplant recipients.

A high level of panel-reactive antibodies (PRA) in potential renal transplant recipients is associated with a long waiting time until transplantation and correlates inversely with graft outcome. We report our experience with the employment of immunoadsorption (IA) using a column composed to sepharose-bound staphylococcal protein A (which has a relatively selective affinity for binding IgG compared with other immunoglobulins) to decrease the PRA levels and expedite transplantation in 6 highly sensitized potential renal transplant recipients (1 primary and 5 awaiting second transplants). All patients had PRA levels of greater than or equal to 70% for a duration of 1 year prior to IA. Only patients with antibody specificity localized to 1 or 2 HLA A or B antigens were accepted for the study. IA procedures were performed on alternate days until a twofold decrease in antibody titer had occurred (maximum: 6 procedures). Repeat procedures were initiated if the HLA antibody titer returned to its baseline value. Intravenous cyclophosphamide (CY) (10 mg/kg/day every 3 weeks) and methylprednisolone (MP) (0.5 mg/kg/day) were provided as adjunctive immunosuppression until transplantation. A total of 44 immunoadsorption procedures were performed (27 primary and 17 repeat) with treatment of 2.49 +/- 0.02 plasma volumes per session. Serum IgG concentration decreased 95 +/- 3% and PRA activity decreased 75 +/- 16% after the primary treatment course. Four patients received cadaveric grafts within 3.7 +/- 1.2 months following the last IA procedure. Three grafts are functioning at 1 year, 8 months, and 8 weeks posttransplant. The remaining graft demonstrated primary nonfunction. All four patients had a past positive crossmatch using pre-IA sera with their respective donors. Patients not transplanted exhibited rapid resynthesis of IgG and a return of the PRA towards baseline levels within a few weeks after IA. We conclude that IA can effectively remove HLA antibodies and expedite graft availability in highly sensitized patients.

Adult↗
PubMed1990

Immunodepletion in xenotransplantation.

Xenograft transplantation is perhaps the most immunologically difficult problem in transplantation today. An overwhelming hyperacute rejection reaction (HAR) occurs within minutes of organ implantation. Preformed antibodies are thought to initiate this process. We used a pig-to-dog renal xenograft transplant model and investigated methods of decreasing the severity of hyperacute rejection. Female pigs weighing 15-20 kg were used as donors. Recipients were mongrel dogs weighing 15-25 kg. Experimental dogs were all given a number of treatments of IgG depletion using an antibody removal system (Dupont-Excorim). This machine immunoadsorbs plasma against a column containing immobilized staphylococcal protein A, which is known to bind the IgG Fc receptor. An 84% reduction in the IgG levels and a 71% reduction in IgM levels was achieved. Postoperative assessment was made of urine output, time to onset of HAR, and histopathological examination of the rejected kidneys. Although cross-matches between donor lymphocytes and recipient sera remained strongly positive in the treated dogs, there was a two- to fourfold reduction in the titers. The time to onset of HAR was prolonged in the experimental group, and the urine output was increased slightly. The histopathologic changes in the experimental group generally showed signs of HAR, but of less intensity than in the nonimmunodepleted control group.

Animals↗
PubMed1989

Induction of c-fos protein by activation of vasopressin receptors in smooth muscle cells.

Stimulation of vasopressin (V1) receptors of rat aortic smooth muscle cells (A-10, ATCC CRL 1476) results in the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) to inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG) with the mobilization of intracellular calcium. When A-10 cells are exposed to arginine vasopressin (AVP), there is an increase in the level of c-fos oncoprotein. The extent of induction of c-fos oncoprotein depends on both the time of exposure of the cells to AVP, reaching a maximum at 60 min after which there is a slow decline, and the concentration of AVP used, with an approximate EC50 of 1 nM which corresponds well with the Kd of vasopressin binding to these receptors. This vasopressin-mediated increase in c-fos protein level is inhibited by a V1/V2 antagonist (SKF 101498) suggesting that this is a receptor-mediated event. In addition dDAVP, a V2 selective agonist, is much less effective than AVP in inducing c-fos protein suggesting that AVP mediates its effect via V1 receptors. Desensitization of vasopressin receptors by prolonged exposure to AVP resulted in no additional induction of c-fos protein level in response to second challenge of AVP. In addition to AVP, phorbol dibutyrate (PDBu), an activator of protein kinase C (PKC), also stimulates the accumulation of c-fos protein although to a lesser extent than AVP. The above data suggest that c-fos protein levels in smooth muscle cells are regulated by AVP and the hormonal effect may be mediated through PI turnover and DAG, IP3 and Ca2+ signals.

Animals↗
PubMed1989

Levels of myc protein, as analyzed by flow cytometry, correlate with cell growth potential in malignant B-cell lymphomas.

We have analyzed c-myc protein expression during the cell cycle in malignant B-cell lymphomas by dual flow cytometric detection of a fluoresceinated polyclonal anti-myc antibody and propidium iodide which binds stochiometrically to DNA. The data obtained were correlated to other parameters of cell activation such as histopathological grading, expression of the activation antigen 4F2, light scatter (proportional to cellular volume), DNA synthesis and percentage of S-phase cells. The c-myc protein level was strongly correlated to parameters of DNA synthesis/content. In addition, the oncoprotein level was largely unvarying from the late G1 phase through the rest of the cell cycle in both malignant cells and normal purified B cells stimulated to proliferate in vitro.

B-Lymphocytes↗