PubMed Health⌕ Search

Biomedical subjects

R T Walton

Publications and source records attributed to R T Walton.

7 recordsLinked to original sources
PubMed2007

Association of the mu-opioid receptor gene with smoking cessation.

We investigated the association of the OPRM1 genotype with long-term smoking cessation and change in body mass index (BMI) following a smoking cessation attempt among smokers who attempted to quit using the nicotine replacement therapy (NRT) patch or placebo in a randomized controlled trial, and were followed-up over an 8-year period following their initial cessation attempt. We also investigated possible sex differences in these relationships, given evidence for sex differences in smoking cessation and central opioid mechanisms, as well as some evidence for sex differences in response to NRT. Our results indicate that OPRM1 genotype may moderate the effect of transdermal nicotine patch compared to placebo during active treatment, with a benefit of active NRT treatment evident in the OPRM1 AA genotype group only and those carrying one or more copies of the G allele demonstrating no benefit of active NRT versus placebo patch. Our results also indicate a sex difference in change in BMI at 8-year follow-up following a smoking cessation attempt, with ex-smokers demonstrating an increase in BMI, and this increase being greater in female subjects than in male subjects. We did not observe any association of OPRM1 genotype with change in BMI, although there was a trend for genotype to influence the observed sex difference in change in BMI over time. Future studies should attempt to replicate these findings, and investigate the relationship between both short- and long-term weight gain and smoking cessation and investigate possible mechanisms that may underlie these processes. Future studies should also investigate the role of OPRM1 genotype and smoking cessation on other appetitive and reward behaviours such as alcohol consumption.

Administration, Cutaneous↗
PubMed2005

Association between the DRD2 gene Taq1A (C32806T) polymorphism and alcohol consumption in social drinkers.

An association between the DRD2 Taq1A (C32806T) polymorphism and social alcohol consumption in the opposite direction to that reported for alcoholism has recently been reported in a male Finnish sample. We attempted to replicate these findings in two independent samples, and extend on previous work by including female participants. The DRD2 A1 allele was significantly associated with reduced alcohol consumption in sample one (P=0.004) and sample two (P=0.015). In sample two there was a significant genotype x sex interaction (P=0.016), with the association of the A1 allele and reduced alcohol consumption significant in men only. This interaction was marginally significant (P=0.042) in a meta-analysis of combined data from both samples, and the main effect of genotype highly significant (P<0.001). Age at time of data collection and cigarette consumption were entered as covariates in all analyses. These results replicate recent previous findings and suggest a possibility that this association may exist in men only, or be stronger in men.

Adult↗
PubMed2001

Computerised advice on drug dosage to improve prescribing practice.

BACKGROUND: Maintaining therapeutic concentrations of toxic drugs is a complex task. Several computer systems have been designed to help doctors determine optimum drug dosage. Significant improvements in health could be achieved if computer advice was shown to be beneficial. OBJECTIVES: To assess whether computer support for drug dosage benefits patients and hence whether it should be more widely available. SEARCH STRATEGY: We searched the Cochrane Effective Practice and Organisation of Care Group specialised register (June 1996), MEDLINE (1966 to June 1996), EMBASE (1980 to June 1996), hand searched the journal Therapeutic Drug Monitoring (1979 to June 1996), reference lists of articles and contacted experts in the field. SELECTION CRITERIA: Randomised trials, interrupted time series and controlled before and after studies of computerised advice on drug dosage. The participants were health professionals responsible for patient care. The outcomes were: any objectively measured change in the behaviour of the health care provider (such as changes in the dose of drug used); any change in the health of patients, resulting from computer support (such as adverse reactions to drugs). DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed study quality. MAIN RESULTS: Fifteen trials involving 1229 patients were included. The drugs studied were theophylline, warfarin, heparin, aminoglycosides, nitroprusside, lignocaine, oxytocin, fentanyl and midazolam. Interventions usually targeted doctors although some studies attempted to influence prescribing by pharmacists and nurses. All included studies took place on acute medical conditions in hospital settings. Although all studies used reliable outcome measures, sample size was often small and only two studies reported a sample size calculation. Computer support for drug dosage gave significant benefits reducing: 1. The time to achieve therapeutic control (standardised mean difference -0.44, 95% CI -0.70 to -0.17); 2. Toxic drug levels (risk difference -0.12, 95% CI -0.24 to -0.01); 3. Adverse reactions (risk difference -0.06, 95% CI -0.12 to 0.00); 4. Length of hospital stay (standardised mean difference -0.32, 95% CI -0.60 to -0.04). There was a tendency for computer support to result in higher doses of drugs, although this did not reach statistical significance. REVIEWER'S CONCLUSIONS: This systematic review provides evidence to support the use of computer assistance in determining drug dosage. Further clinical trials are necessary to determine whether the benefits seen in specialist applications can be realised in general use.

Drug Therapy, Computer-Assisted↗
PubMed2000

Association between polymorphisms in dopamine metabolic enzymes and tobacco consumption in smokers.

Central dopaminergic reward pathways give rise to dependence and are activated by nicotine. Allelic variants in genes involved in dopamine metabolism may therefore influence the amount of tobacco consumed by smokers. We developed assays for polymorphisms in dopamine beta-hydroxylase (DBH), monoamine oxidase (MAO) and catechol O-methyl transferase (COMT) using the polymerase chain reaction with sequence specific primers (PCR-SSP). We then typed 225 cigarette smokers to assess whether genotype was related to the number of cigarettes smoked a day. Smokers with DBH 1368 GG genotype smoked fewer cigarettes than those with GA/AA [mean difference -2.9 cigarettes, 95% confidence interval (CI) -5.5, -0.4; P = 0.022]. The effect reached statistical significance in women (-3.8, 95% CI -6.4, -1.0, P = 0.007) but not in men (-1.5, 95% CI -6.0, 3.0, P = 0.498). Overall, the effect was greater when analysis was confined to Caucasians (-3.8, 95% CI -6.6, -1.1, P = 0.007). Smokers with MAO-A 1460 TT/TO smoked more cigarettes than those with CC/CT/CO (2.9, 95% CI 0.6, 5.1, P = 0.013). Within each sex group, the trend was similar but not statistically significant (difference for men 2.9, 95% CI -1.0, 6.7; for women 2.0, 95% CI -0.7, 4.8). The effect of the allele was greater in smokers with a high body mass index (> 26) (difference 5.1, 95% CI 1.4, 8.8, P = 0.008). More heavy smokers (> 20 a day) had the DBH 1368A allele when compared to light smokers (< 10 a day). (Relative risk 2.3, 95% CI 1.1, 5.0, P = 0.024.) The trend for increasing prevalence of the DBH A allele in heavy smokers was greater when analysis was restricted to Caucasians (relative risk 3.2, 95% CI 1.3, 8.2, P = 0.004). Conversely, heavy smokers were less likely to have the MAO-A 1460C allele (relative risk 0.3, 95% CI 0.1, 0.7, P = 0.012). Variations in DBH and MAO predict whether a person is a heavy smoker and how many cigarettes they consume. Our results support the view that these enzymes help to determine a smoker's requirement for nicotine and may explain why some people are predisposed to tobacco addiction and why some find it very difficult to stop smoking. This finding has important implications for smoking prevention and offers potential for developing patient-specific therapy for smoking cessation.

Adult↗
PubMed1997

Evaluation of computer support for prescribing (CAPSULE) using simulated cases.

OBJECTIVE: To evaluate the potential effect of computer support on general practitioners' prescribing, and to compare the effectiveness of three different support levels. DESIGN: Crossover experiment with balanced block design. SUBJECTS: Random sample of 50 general practitioners (42 agreed to participate) from 165 in a geographically defined area of Oxfordshire. INTERVENTIONS: Doctors prescribed for 36 simulated cases constructed from real consultations. Levels of computer support were control (alphabetical list of drugs), limited support (list of preferred drugs), and full support (the same list with explanations available for suggestions). MAIN OUTCOME MEASURES: Percentage of cases where doctors ignored a cheaper, equally effective drug; prescribing score (a measure of how closely prescriptions matched expert recommendations); interview to elicit doctors' views of support system. RESULTS: Computer support significantly improved the quality of prescribing. Doctors ignored a cheaper, equally effective drug in a median 50% (range 25%-75%) of control cases, compared with 36% (8%-67%) with limited support and 35% (0-67%) with full support (P < 0.001). The median prescribing score rose from 6.0 units (4.2-7.0) with control support to 6.8 (5.8 to 7.7) and 6.7 (5.6 to 7.8) with limited and full support (P < 0.001). Of 41 doctors, 36 (88%) found the system easy to use and 24 (59%) said they would be likely to use it in practice. CONCLUSIONS: Computer support improved compliance with prescribing guidelines, reducing the occasions when doctors ignored a cheaper, equally effective drug. The system was easy to operate, and most participating doctors would be likely to use it in practice.

Decision Making, Computer-Assisted↗