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Biomedical subjects

Robert West

Publications and source records attributed to Robert West.

At least 37 records · Page 2Linked to original sources
PubMed2006

The ATTEMPT cohort: a multi-national longitudinal study of predictors, patterns and consequences of smoking cessation; introduction and evaluation of internet recruitment and data collection methods.

AIMS: The ATTEMPT study was designed to chart the natural history of smoking cessation and associated short-term health outcomes and effects on medical resource utilization among a cohort recruited across multiple countries. This paper describes the methods for recruitment and follow-up, the baseline population characteristics of the enrolled population and 1-year response rates. DESIGN: ATTEMPT is a multi-national prospective cohort study that used the internet for subject recruitment and online assessments every 3 months for 2.5 years. SETTING: Subjects were recruited via e-mail from existing internet panels [Canada (n = 208), France (n = 201), the United Kingdom (n = 200) and the United States (n = 1400]. SUBJECTS: Panel members who were aged 35-65 years, smoked at least five cigarettes per day and at initiation stated an intention to quit smoking within the next 3 months were eligible for this study. MEASUREMENTS: Measures included: attempts to quit, smoking status, smoking history, nicotine dependence and craving, methods used to quit smoking, reasons for quitting or failing to quit smoking, short-term health effects, health resource utilization, wellbeing, concern over weight gain, confidence in preventing weight gain, body weight and demographics. In addition, in-home assessments of weight were undertaken by field staff for a random sample of US participants. FINDINGS: Country-specific recruitment was completed within 17 days. The recruitment method produced a sample with characteristics broadly similar to those found in national surveys of smokers except for higher prevalence of obesity in the US and Canadian samples and higher educational level. At the end of 1 year the response rate was 52%, and there was little evidence of differential loss to follow-up by key subject characteristics. Weight reported in the survey was found to correlate highly with weight measured during in-home visits. CONCLUSION: This paper demonstrates the feasibility of enrolling and following a diverse cohort of smokers for self-reported health and behaviour measures via the internet.

Adult↗
PubMed2006

Early dating predicts smoking during adolescence: A prospective study.

AIM: To examine the relationship between dating and smoking behaviour. DESIGN: A 5-year prospective study. SETTING: Thirty-six schools in South London, England. PARTICIPANTS: A socio-economically and ethnically diverse sample of students (n = 4319 at baseline) took part in the study, providing annual assessments from age 11-16 years. MEASUREMENTS: Questionnaire items assessed dating status, smoking status, friends and family smoking, psychological wellbeing, popularity and conduct, pubertal status, gender, ethnicity and deprivation. Cotinine assays provided biochemical verification of smoking status. FINDINGS: At age 11-12, 18% [corrected] of girls and 29% [corrected] of boys reported having a boyfriend or girlfriend. Logistic regressions showed being an early 'dater' to be a strong predictor of later smoking uptake at each study year, with odds ratios ranging from 3.03 to 8.96 among girls and 1.87 to 5.85 among boys. These associations remained significant after controlling for potential confounding factors, including past smoking and pubertal stage. There was minimal evidence that having smoked by age 11-12 predicted later dating. CONCLUSIONS: The association between early dating and later smoking is strong, and not explained by obvious confounders or dependent on the influence of past smoking experience. The use of smoking to maintain a popular image, and the link between both behaviours and aspirations towards maturity, are potential explanations for the effect. Identification of adolescents dating early could help to target prevention of later smoking uptake.

Adolescent↗
PubMed2006

An uncontrolled trial of cytisine (Tabex) for smoking cessation.

OBJECTIVES: Cytisine (Tabex) has been licensed in Eastern Europe as an aid to smoking cessation for 40 years. Cytisine is a partial agonist with high affinity binding to the alpha4beta2 nicotinic acetylcholine receptor believed to be central to the rewarding effect of nicotine. There is insufficient information on effectiveness to warrant licensing by modern standards. To assess whether full-scale controlled trials are warranted, this study sought to obtain an estimate of the 12-month continuous abstinence rates of smokers using cytisine with minimal behavioural support. DESIGN: An uncontrolled, open-label trial. SETTING: A smokers' clinic in an oncology centre in Warsaw, Poland. SUBJECTS: 436 consecutive attendees of the smokers' clinic of whom 191 were male. The mean dependence score (Fagerstrom Test for Nicotine Dependence) was 6.1. INTERVENTION: The standard regimen of Tabex (cytisine) was used, involving 25 days of treatment with minimal behavioural support. MAIN OUTCOME MEASURE: Self-reported continuous abstinence for 12 months; with abstinence verified by carbon monoxide at the final follow up (after 12 months). RESULTS: 60 participants (13.8% of the total sample) were abstinent for 12 months. Of the 315 subjects, who had taken the drug, 49 (15.5%) stopped cytisine because of adverse effects (mostly gastric disturbances and nausea), although they were not serious. The frequency of the minor adverse effects, primarily gastric disturbance, was similar to that observed in previous studies with the drug. CONCLUSIONS: The long-term abstinence rates were similar to those observed in smokers receiving nicotine replacement therapy. Full-scale randomised trials of cytisine (Tabex), conducted to the standards required by regulatory authorities, are warranted.

Adult↗
PubMed2005

Assessing DSM-IV nicotine withdrawal symptoms: a comparison and evaluation of five different scales.

OBJECTIVE: This study evaluated four of the major scales used to measure nicotine withdrawal symptoms plus one new scale. METHODS: Eighty-three smokers were randomly assigned to continue smoking (n=37) or abstain completely for 24 h (n=46), by which time the symptoms should become manifest. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) withdrawal symptoms (irritability, depression, restlessness, insomnia, anxiety, hunger and poor concentration) plus craving were measured at baseline and after 24 h. The scales tested were the Minnesota Nicotine Withdrawal Scale (MNWS), the Mood and Physical Symptoms Scale (MPSS), the Shiffman Scale (SS), the Wisconsin Smoking Withdrawal Scale (WSWS) and the newly developed Cigarette Withdrawal Scale (CWS). RESULTS: Measurement of withdrawal symptoms was robust in the case of all scales for total withdrawal score, irritability, restlessness, poor concentration and craving. The MNWS and CWS were less sensitive to depression; the WSWS and MNWS were less sensitive to insomnia; the MPSS was less sensitive to anxiety and hunger; the CWS and WSWS did not include restlessness as a distinct symptom; the SS did not include insomnia, and its scores tended to decline over time during ad lib smoking. Longer scales, using multiple items to measure each symptom, did not yield more reliable or accurate measurement than briefer scales. CONCLUSIONS: To measure total withdrawal discomfort or craving, all of the scales examined can be recommended, and there is little to choose between them apart from length. When it comes to assessing individual symptoms, different scales have different strengths and weaknesses. There would be merits in developing a new questionnaire that combined the best features of the scales tested.

Adolescent↗
PubMed2005

Neural correlates of conflict processing.

In this study we examined the neural correlates of conflict processing in the Stroop, counting, and digit-location tasks using event-related brain potentials (ERPs). The behavioral data revealed robust interference in response time and accuracy for all tasks. The interference effect for response time was greater in the Stroop task than the other tasks; in contrast, the interference effect for response accuracy was greater in the counting tasks than the other tasks. The N450 and sustained potential (SP) were elicited in each task. Partial least-squares (PLS) analysis was used to examine the structural relationships between the ERPs, task design, and behavior. TaskPLS analysis revealed that the N450 and SP were associated with a single latent variable leading to the suggestion that a common set of neural generators was recruited during conflict processing across the tasks and that there were differences between ERPs related to early processing across the three tasks. BehavioralPLS analysis revealed that the amplitude of the SP was positively correlated with response time and accuracy, indicating that this modulation of the ERPs may be related to response selection rather than to conflict resolution.

Adolescent↗
PubMed2005

Formation of disilanes in the reaction of stable silylenes with halocarbons.

Reactions of stable silylenes 1 and 2 with a variety of halogenated organic compounds have been studied. Depending on the nature of the halocarbon, the products can be disilanes, LSiX-LSiR, or monosilanes, LSiXR, or a mixture of both types of products. Hexachloroethane reacts with the silylenes to give mainly the dichlorodisilane, LSiX-LSiX. The experimental results are rationalized in terms of several related free-radical chain mechanisms.

Crystallography, X-Ray↗
PubMed2005

Perceived barriers to and benefits of attending a stop smoking course during pregnancy.

OBJECTIVE: During pregnancy, the uptake of smoking cessation courses is very low. We assessed perceived barriers to and benefits of attending a cessation course during pregnancy. METHODS: A decisional-balance questionnaire was devised, including 10 statements reflecting benefits of attending a cessation course and 10 statements of barriers to attendance. The questionnaire was delivered via the Internet and targeted pregnant smokers/recent ex-smokers. Participants completed the questionnaire on a single occasion, indicating their agreement with each statement. RESULTS: Among 443 respondents, the most frequently endorsed barriers were 'Being afraid of disappointing myself if I failed' (54%) and not tending to seek help for this sort of thing (41%). The most frequently endorsed benefits were advice about cigarette cravings (74%) and praise and encouragement with quitting (71%). A greater interest in receiving help with quitting from a counselor was significantly associated with: being older, lower income, husband/partner advising cessation and less confidence in quitting. CONCLUSION: Pregnant smokers perceive many benefits of smoking cessation courses. However, these women also perceive many barriers to attendance and studies are needed to evaluate interventions for overcoming such barriers. PRACTICE IMPLICATIONS: Smoking cessation services need to address the perceived barriers to attending stop smoking courses during pregnancy, to publicise the benefits of these courses and to target women who feel that they cannot quit without this type of support.

Adolescent↗
PubMed2005

Triggering anti-smoking advice by GPs: mode of action of an intervention stimulating smoking cessation advice by GPs.

OBJECTIVE: To assess the mode of action of an intervention (GP desktop resource, GDR) that increased the frequency of general practitioner (GP) advice to stop smoking. METHODS: Analyses were undertaken to differentiate between three hypotheses regarding the mode of action of the GDR. That the GDR acts: (1) by altering GPs' attitudes, (2) independently of attitudes in prompting GPs to intervene with smokers or (3) by altering the relationship between attitudes and behaviour. RESULTS: The GDR was an independent predictor of the number of patients advised to stop smoking (beta = .345, p < .001). Concern about the doctor-patient relationship was the only attitude variable that independently predicted advice giving, in this case negatively (beta = -.465, p < .001). Possession of the GDR did not alter GPs' views on whether intervening with smokers harmed the doctor-patient relationship, but did weaken the relationship between this attitude item and the number of patients advised to stop smoking (beta = .595, p < .001 for the interaction). CONCLUSION: This study is the first to show that concern over the doctor-patient relationship was an independent predictor of advice giving while in other studies it has merely been noted as something that GPs express concern about. A simple device designed to trigger action on the part of GPs appeared to work by mitigating the negative effect of an attitudinal barrier to action. It would be interesting to explore this phenomenon more generally in relation to health promotion activities on the part of health professionals. PRACTICE IMPLICATIONS: Recommendations that GPs engage in health promotion activities with their patients need to consider that GPs' concerns over harming the doctor-patient relationship may deter them from making such interventions. The GDR appears to be effective in prompting GPs to advise their smoking patients to stop and its widespread distribution to GPs should be considered.

Adult↗
PubMed2005

Radical reactions of a stable N-heterocyclic germylene: EPR study and DFT calculation.

The first radical adducts of a stable N-heterocyclic germylene were investigated. Novel radical species were produced from a variety of precursors and studied by EPR spectroscopy. DFT (B3LYP) calculations of radical adducts of different (C, Si, Ge) unsaturated N-heterocyclic divalent species with phenoxyl radical show that in the radicals studied the unpaired electron is delocalized over the five-membered ring and the spin density on the central atoms decreases in the following order: C > Si > Ge. These trends can be understood in terms of zwitterionic structure of radical adducts.

Journal Article↗
PubMed2005

The effects of working memory demands on the neural correlates of prospective memory.

Event-related brain potentials (ERPs) were used to examine the reciprocal costs of working and prospective memory loads on the neural correlates of the realization of delayed intentions and the detection of target stimuli. The electrophysiological data revealed several interesting results: (1) distinct modulations of the ERPs were elicited by working memory targets and prospective memory cues, (2) working memory load modulated the amplitude of the N300 elicited by prospective memory cues, (3) prospective memory load was associated with a broadly distributed sustained modulation that began shortly after stimulus onset, and (4) brain-behavior correlations between the neural correlates of prospective memory and working memory varied with the working memory demands of the ongoing activity. These findings appear to indicate that attentional processes associated with the detection of prospective memory cues are sensitive to the working memory demands of the ongoing activity and that different processes may support prospective memory depending on the working memory demands of the ongoing activity.

Adolescent↗
PubMed2005

Imaging of Titan from the Cassini spacecraft.

Titan, the largest moon of Saturn, is the only satellite in the Solar System with a substantial atmosphere. The atmosphere is poorly understood and obscures the surface, leading to intense speculation about Titan's nature. Here we present observations of Titan from the imaging science experiment onboard the Cassini spacecraft that address some of these issues. The images reveal intricate surface albedo features that suggest aeolian, tectonic and fluvial processes; they also show a few circular features that could be impact structures. These observations imply that substantial surface modification has occurred over Titan's history. We have not directly detected liquids on the surface to date. Convective clouds are found to be common near the south pole, and the motion of mid-latitude clouds consistently indicates eastward winds, from which we infer that the troposphere is rotating faster than the surface. A detached haze at an altitude of 500 km is 150-200 km higher than that observed by Voyager, and more tenuous haze layers are also resolved.

Journal Article↗
PubMed2005

Why evidence for the fetal origins of adult disease might be a statistical artifact: the "reversal paradox" for the relation between birth weight and blood pressure in later life.

Some researchers have recently questioned the validity of associations between birth weight and health in later life. They argue that these associations might be due in part to inappropriate statistical adjustment for variables on the causal pathway (such as current body size), which creates an artifactual statistical effect known as the "reversal paradox." Computer simulations were conducted for three hypothetical relations between birth weight and adult blood pressure. The authors examined the effect of statistically adjusting for different correlations between current weight and birth weight and between current weight and adult blood pressure to assess their impact on associations between birth weight and blood pressure. When there was no genuine relation between birth weight and blood pressure, adjustment for current weight created an inverse association whose size depended on the magnitude of the positive correlations between current weight and birth weight and between current weight and blood pressure. When there was a genuine inverse relation between birth weight and blood pressure, the association was exaggerated following adjustment for current weight, whereas a positive relation between birth weight and blood pressure could be reversed after adjusting for current weight. Thus, researchers must consider the reversal paradox when adjusting for variables that lie within causal pathways.

Adult↗
PubMed2005

The attitude of maternity staff to, and smoking cessation interventions with, childbearing women in London.

OBJECTIVES: To explore the self-reported smoking-cessation interventions of maternity staff with pregnant smokers, and their attitudes towards smoking in pregnancy. DESIGN AND SETTING: Postal survey of all 137 maternity staff (clinical grades A-H) at a large acute hospital in London; 78 questionnaires were completed (response rate: 57%). FINDINGS: Over two-thirds of respondents (71%) reported not advising any pregnant women to give up smoking within the previous 7 days. However, nearly two-thirds (64%) felt that women should not be left to make up their own minds about whether or not to smoke during pregnancy, and even more (81%) agreed or strongly agreed that many pregnant women would like to give up smoking but need help and advice on how to succeed. Helping a pregnant woman to give up smoking was seen as being one of the most important things a midwife can do by 73% of the respondents. CONCLUSIONS: Although the reported attitudes were supportive of the midwife's role in smoking cessation, they did not translate into practice. The level of smoking cessation interventions was low. IMPLICATIONS FOR PRACTICE: The findings from this study indicate some deficits in knowledge among maternity staff that training may address. Raising awareness of the local smoking-cessation service, and how to refer women to it, may increase the number of referrals maternity staff make.

Adult↗
PubMed2005

Neural correlates of prospective and retrospective memory.

This study examines the event-related brain potential (ERP) correlates of retrieval processes in prospective and retrospective memory (i.e., recognition and cued-recall). In contrast to previous research that has compared performance on tasks measuring prospective and retrospective memory, the stimulus materials and encoding and response demands of the prospective and retrospective components of the tasks were reasonably well matched for the two forms of memory. This resulted in the primary difference between the assessments of prospective and retrospective memory being the requirement for self-initiated retrieval in prospective memory. Analyses of mean amplitude measures revealed modulations of the ERPs typically associated with prospective memory (i.e., N300 and prospective positivity) and retrospective memory (i.e., FN400, parietal positivity and frontal slow waves). Partial least squares analyses revealed one latent variable related to the retrieval of a previously studied item that contrasted retrospective hits and prospective hits from ongoing activity trials and prospective lures; and one latent variable uniquely associated with prospective hits. These findings indicate that similar neural processes support retrieval in prospective and retrospective memory and that the realization of intentions is additionally dependent on processes that are uniquely related to prospective memory.

Adolescent↗
PubMed2005

Adjustments of cognitive control in younger and older adults.

The effects of aging on behavioral and electrophysiological indices of adjustments of cognitive control were examined in two experiments. Specifically, we considered the effects of aging of patterns of response time and modulations of the event-related brain potentials (ERPs) on sequential trial effects, error-related slowing, and local switch costs in two modified Stroop tasks. The behavioral data reveal that sequential trial effects were observed when color, but not word, identification was required and that these effects were similar in younger and older adults; that the degree of error-related slowing was similar for younger and older adults in Experiment 1 and greater in older than younger adults in Experiment 2; that local switch costs in response time were similar in younger and older adults and that the requirement to switch between color and word identification resulted in a dramatic increase in the number of color intrusion errors in older adults in Experiment 2. The ERP data revealed that endogenously generated adjustments of cognitive control were associated with a parietal slow wave that mirrored the behavioral data and was similar in amplitude in younger and older adults and an anterior frontal slow wave that was absent in older adults. The ERP data also revealed that an enhancement of the P3 component and a frontal slow wave that differentiated color switch trials from color non-switch and word trials in younger adults were attenuated in older adults.

Adult↗
PubMed2005

Outcome criteria in smoking cessation trials: proposal for a common standard.

Smoking cessation treatment is now integrated into many health-care systems and a major research effort is under way to improve current success rates. Until now results from randomized clinical trials have been reported in many different ways, leading to problems of interpretation. We propose six standard criteria comprising the 'Russell Standard' (RS). These criteria are applicable to trials of cessation aids where participants have a defined target quit date and there is face-to-face contact with researchers or clinic staff, as follows. (1) Follow-up for 6 months (RS6) or 12 months (RS12) from the target quit date or the end of a predefined 'grace period'; (2) self-report of smoking abstinence over the whole follow-up period allowing up to five cigarettes in total; (3) biochemical verification of abstinence at least at the 6-month or 12-month follow-up point; (4) use of an 'intention-to-treat' approach in which data from all randomized smokers are included in the analysis unless they have died or moved to an untraceable address (participants who are included in the analysis are counted as smokers if their smoking status at the final follow-up cannot be determined); (5) following-up 'protocol violators' and using their true smoking status in the analysis; and (6) collecting follow-up data blind to smokers' allocation to trial group. We believe that these criteria provide the best compromise between practicability and surrogacy for long-term cessation and will enable meaningful comparison between studies. There may be good reasons why other outcome criteria would also be reported, and studies that involve interventions with special groups or where there is no designated target quit date or face to face contact would need to adapt these criteria accordingly.

Humans↗
PubMed2005

Randomized controlled trial of a web-based computer-tailored smoking cessation program as a supplement to nicotine patch therapy.

AIM: To assess the efficacy of World Wide Web-based tailored behavioral smoking cessation materials among nicotine patch users. DESIGN: Two-group randomized controlled trial. SETTING: World Wide Web in England and Republic of Ireland. PARTICIPANTS: A total of 3971 subjects who purchased a particular brand of nicotine patch and logged-on to use a free web-based behavioral support program. INTERVENTION: Web-based tailored behavioral smoking cessation materials or web-based non-tailored materials. MEASUREMENTS: Twenty-eight-day continuous abstinence rates were assessed by internet-based survey at 6-week follow-up and 10-week continuous rates at 12-week follow-up. FINDINGS: Using three approaches to the analyses of 6- and 12-week outcomes, participants in the tailored condition reported clinically and statistically significantly higher continuous abstinence rates than participants in the non-tailored condition. In our primary analyses using as a denominator all subjects who logged-on to the treatment site at least once, continuous abstinence rates at 6 weeks were 29.0% in the tailored condition versus 23.9% in the non-tailored condition (OR = 1.30; P = 0.0006); at 12 weeks continuous abstinence rates were 22.8% versus 18.1%, respectively (OR = 1.34; P = 0.0006). Moreover, satisfaction with the program was significantly higher in the tailored than in the non-tailored condition. CONCLUSIONS: The results of this study demonstrate a benefit of the web-based tailored behavioral support materials used in conjunction with nicotine replacement therapy. A web-based program that collects relevant information from users and tailors the intervention to their specific needs had significant advantages over a web-based non-tailored cessation program.

Administration, Cutaneous↗