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Biomedical subjects

Robert West

Publications and source records attributed to Robert West.

At least 55 records · Page 3Linked to original sources
PubMed2005

Effects of aging and working memory demands on prospective memory.

The current study used event-related brain potentials (ERPs) to examine the effects of aging, increasing the working memory demands of the ongoing activity, and a prospective memory load on the neural correlates of prospective remembering and target recognition. The behavioral data revealed that the success of prospective memory was sensitive to working memory load in younger, but not older, adults and that a prospective memory load had a greater effect on the performance of older adults than that of younger adults. The ERP data revealed age-related differences in the neural correlates of the detection of prospective cues, post-retrieval processes that support prospective memory, and target recognition. Our results support the hypothesis that there are age-related differences in the ability to recruit preparatory attentional processes that underlie prospective memory, and demonstrate that younger and older adults may recruit somewhat different neural generators to support prospective memory and working memory.

Adolescent↗
PubMed2005

Disruptions of preparatory attention contribute to failures of prospective memory.

In two experiments, we examine the efficacy of preparatory attentional processes and intention superiority as explanations of the finding that response time (RT) for prospective memory (PM) cue misses is often faster than that for ongoing activity trials or PM cue hits. RT was faster for prospective misses than for ongoing activity trials, demonstrating an intention superiority effect. RT was also faster for ongoing activity trials preceding prospective misses than for those preceding prospective hits. We interpret this finding as reflecting variation in the efficiency of preparatory attentional processes during task performance, leading to failures of PM when preparatory attentional processes are suboptimal.

Adolescent↗
PubMed2004

Construction of a cyclin D1-Cdk2 fusion protein to model the biological functions of cyclin D1-Cdk2 complexes.

Cyclin D1 is frequently overexpressed in human breast cancers, and cyclin D1 overexpression correlates with poor prognosis. Cyclin D1-Cdk2 complexes were previously observed in human breast cancer cell lines, but their role in cell cycle regulation and transformation was not investigated. This report demonstrates that Cdk2 in cyclin D1-Cdk2 complexes from mammary epithelial cells is phosphorylated on the activating phosphorylation site, Thr(160). Furthermore, cyclin D1-Cdk2 complexes catalyze Rb phosphorylation on multiple sites in vitro. As a model to investigate the biological and biochemical functions of cyclin D1-Cdk2 complexes, and the mechanisms by which cyclin D1 activates Cdk2, a cyclin D1-Cdk2 fusion gene was constructed. The cyclin D1-Cdk2 fusion protein expressed in epithelial cells was phosphorylated on Thr(160) and catalyzed the phosphorylation of Rb on multiple sites in vitro and in vivo. Kinase activity was not observed if either the cyclin D1 or Cdk2 domain was mutationally inactivated. Mutational inactivation of the cyclin D1 domain prevented activating phosphorylation of the Cdk2 domain on Thr(160). These results indicate that the cyclin D1 domain of the fusion protein activated the Cdk2 domain through an intramolecular mechanism. Cells stably expressing the cyclin D1-Cdk2 fusion protein exhibited several hallmarks of transformation including hyperphosphorylation of Rb, resistance to TGFbeta-induced growth arrest, and anchorage-independent proliferation in soft agar. We propose that cyclin D1-Cdk2 complexes mediate some of the transforming effects of cyclin D1 and demonstrate that the cyclin D1-Cdk2 fusion protein is a useful model to investigate the biological functions of cyclin D1-Cdk2 complexes.

Animals↗
PubMed2004

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

Reaction of the stable silylene, 1,3-di-tert-butyl-1,3,2-diazasilol-2-ylidene, with the free radical sources TEMPO, Hg[P(O)(OPri)2]2, (CO)3CpM-MCp(CO)3 (M = W, Mo), (CO)5Re-Re(CO)5, and toluene leads to radical adducts. The EPR spectra of these radicals indicate that the unpaired electron is delocalized over the silicon-containing five-membered ring.

Journal Article↗
PubMed2004

Evaluation of the mood and physical symptoms scale (MPSS) to assess cigarette withdrawal.

RATIONALE: The mood and physical symptoms scale (MPSS) was developed in the early 1980s to assess cigarette withdrawal symptoms, and variants of it have been used for 20 years. To date, no paper has been published on the properties of the scale. OBJECTIVES: To evaluate psychometric properties of MPSS and the interrelationship between the key tobacco withdrawal symptoms. METHODS: The core elements of the MPSS involve 5-point ratings of depressed mood, irritability, restlessness, difficulty concentrating and hunger and 6-point ratings of strength of urges to smoke and time spent with these urges. The data set chosen for analysis was well suited to the task in that it involved a relatively large sample, abstinence was defined as "not a puff" for 24 h biochemically verified, participants were not using any medication that would have reduced withdrawal discomfort (e.show $132#g. nicotine patch), the abstinence rate was very high resulting in minimal bias due to attrition, and ratings were provided on three occasions prior to abstinence. The study involved 111 smokers setting a target quit date of whom 106 attempted abstinence and 96 achieved it. RESULTS: The MPSS items were stable prior to abstinence and sensitive to abstinence. Post-abstinence increases in mood and physical symptoms demonstrated a high level of internal coherence. Ratings of urges to smoke correlated highly with changes in mood and other symptoms. Ratings of hunger correlated less well with the scale as a whole and may involve some distinct processes. CONCLUSIONS: The MPSS meets the key requirements of a cigarette withdrawal scale. Although urge to smoke/craving was not included in the list of DSM-IV withdrawal symptoms, it should be regarded as forming part of the withdrawal syndrome.

Adult↗
PubMed2004

The Raman spectrum and aromatic stabilization in a cyclic germylene.

For the stable germylene, N,N'-di-tert-butyl-1,3-diaza-2-germacyclopent-4-en-2-ylidene, 2, the Raman line for the cyclic C=C stretching mode is strongly enhanced and shifted to longer wavelength, compared with that in reference compounds. The enhancement and frequency shift are even greater than those found for the corresponding stable silylene 1. These results, along with NMR evidence and theoretical calculations, suggest that the aromatic electron delocalization is even greater in the germylene than that in the silylene.

Journal Article↗
PubMed2004

Acute effects of a short bout of moderate versus light intensity exercise versus inactivity on tobacco withdrawal symptoms in sedentary smokers.

RATIONALE: A previous study found that a 10-min bout of moderate intensity exercise reduced cigarette withdrawal symptoms and desire to smoke in sedentary smokers but the effect may have been due to participants focusing attention on physical activity rather than the activity itself. OBJECTIVES: This study examined the effect of 5 min of moderate intensity exercise and 5 min of light intensity exercise on tobacco withdrawal symptoms amongst sedentary smokers. METHODS: Eighty-four smokers attended a laboratory session having abstained from smoking for between 11 and 14 h. Participants were randomly allocated to one of three conditions: (i) light intensity exercise [ n=28; 10-20% of heart rate reserve (HRR)]; (ii) moderate intensity exercise ( n=28; 40-60% HRR), (iii) a passive control condition ( n=28). Both exercise conditions involved 5 min of stationary cycling and participants rated tobacco withdrawal symptoms and cravings immediately before exercise (baseline), during exercise at 2.5 min, immediately following exercise, then after 5 and 10 min of rest. Control participants made the same ratings across an equivalent time period. RESULTS: For moderate intensity exercise compared to light intensity exercise and control there was a significant reduction in strength of desire to smoke, relative to baseline, both during exercise and up to 5 min post-exercise. Relative to baseline, there were also significant reductions in restlessness, stress, tension and poor concentration at 5 and 10 min post-exercise, for moderate intensity exercise compared to light intensity exercise and control. CONCLUSIONS: Five minutes of moderate intensity exercise is associated with a short-term reduction in desire to smoke and tobacco withdrawal symptoms. Very brief bouts of exercise may therefore be useful as an aid to smoking cessation.

Adolescent↗
PubMed2004

Acute reduction in secretory immunoglobulin A following smoking cessation.

Smokers report an increase in upper respiratory infections in the early phase of stopping smoking. One possible cause is a depletion in secretory immunoglobulin A (S-IgA) which has been observed in one study. The present study sought to establish this finding in smokers using nicotine patches. Ninety-two smokers, trying to stop smoking, were assessed whilst smoking and for up to six weeks of abstinence. All smokers were prescribed 15 mg 16-h nicotine patches. Among abstinent smokers, changes in S-IgA and saliva volume were assessed. During the preliminary analyses, we observed that for the pre-smoking cessation measure a longer time since the last cigarette was significantly related to lower S-IgA levels (P = 0.006). Consequently, the main analysis, of changes in S-IgA from pre-cessation to post-cessation, was confined to those who had smoked within 0.5-1.5 h of the pre-cessation measure (n = 51). There was a significant decline in S-IgA, relative to pre-smoking abstinence levels, following abstinence of one day (P = 0.027), but levels returned to pre-abstinence values after one week. There was no evidence of any significant changes in saliva volume following smoking cessation, relative to pre-cessation levels. Users of 15 mg patches are likely to experience a decline in S-IgA levels on the first day of smoking cessation, independent of saliva volumes, and this decline in S-IgA is likely to occur acutely, within the first few hours of smoking abstinence. This acute drop in S-IgA appears to stem from a factor other than depletion of nicotine from the body. The observed decrease in S-IgA may help to explain the increased susceptibility of smokers to upper respiratory tract infections in the immediate post-cessation period.

Administration, Cutaneous↗
PubMed2004

A survey of pregnant smokers' interest in different types of smoking cessation support.

The aim of this study was to survey pregnant smokers' interest in different types of smoking cessation support. Interest in cessation support was assessed via telephone interviews with women identified as smokers at their first antenatal visit. Of 206 pregnant smokers interviewed, 87% (179/206) reported wanting to stop smoking, of whom 69% (124/179) expressed an interest in receiving help with stopping. Interest was highest for behavioural support (82%, 102/124) and self-help materials (77%, 95/124). There was a significant preference for individual versus group appointments, for 'buddying' among those not in professional/managerial occupations versus those in professional/managerial occupations, and for behavioural support among non-Caucasians versus Caucasians. These findings highlight the high level of interest expressed in support with stopping smoking among pregnant smokers. Smoking cessation services may benefit through offering a range of interventions for pregnant smokers, through considering ethnic and occupational status, and through routinely offering individual appointments.

Adolescent↗
PubMed2004

Recommendation for the assessment of tobacco craving and withdrawal in smoking cessation trials.

This paper addresses methodological issues in the assessment of nicotine withdrawal and craving in clinical trials of smoking cessation therapies. We define withdrawal as a syndrome of behavioral, affective, cognitive, and physiological symptoms, typically transient, emerging upon cessation or reduction of tobacco use and causing distress or impairment of behavioral function. Offset effects (effects related to removal of a direct nicotine effect) are sustained effects of cessation or reduction of tobacco use that cause distress or impairment. Withdrawal and craving are important as potential predictors of relapse, as mediators and markers of treatment effects, and as clinical phenomena in their own right. Symptoms recommended for assessment include craving, irritability, depression, restlessness, sleep disturbance, difficulty concentrating, increased appetite, and weight gain; anxiety deserves further study. We recommend reporting of data on each of these individual symptoms, and use of multiple-item assessments. Although some standardized measures of withdrawal have promising psychometric properties, no measure has yet fully established its reliability, validity, and broad applicability and, therefore, we do not currently favor universal adoption of any one measure. Assessment of objective indices of withdrawal (e.g., hormonal changes) is currently technically challenging and of unknown value. Although weekly assessment may suffice in some large trials, more intensive measurement can provide better sensitivity. Analyses of withdrawal should include baseline measures and be sensitive to potential instability in baseline. Analytic approaches should take into account potential bias when only abstinent subjects are examined. Conversely, heterogeneity should be considered when smoking subjects are included in intent-to-treat analyses. Withdrawal data from clinical trials focused on assessing abstinence rates may be biased because of progressive subject loss to dropout and relapse; different designs and approaches are needed to investigate the process and natural history of craving and withdrawal.

Clinical Trials as Topic↗
PubMed2004

GP prescribing of nicotine replacement and bupropion to aid smoking cessation in England and Wales.

AIMS: Prescribing nicotine replacement therapy (NRT) or bupropion for smoking cessation is of considerable importance to public health but little is known about prescribing practices. This paper examines general practitioners' (GPs') prescribing patterns in Britain where these drugs are reimbursed. The results have implications for other health-care systems considering introducing reimbursement. DESIGN, PARTICIPANTS AND SETTING: Postal survey conducted in 2002 of a random sample of 1088 GPs in England and Wales, of whom 642 (59%) responded. MEASURES: Number of requests GPs reported having received from patients for NRT and bupropion over the past month, the number of prescriptions they reported issuing and ratings of attitudes to these medications. FINDINGS: GPs reported receiving an average of 4.3 requests for NRT and 1.9 for bupropion in the previous month. They reported issuing 3.5 prescriptions for NRT and 1.2 for bupropion. Almost all GPs accepted that NRT (95%) and bupropion (97%) should be reimbursable on National Health Service (NHS) prescription. However, a significant minority of those who received requests for prescriptions did not issue any (8% for NRT and 26% for bupropion). This was related to whether they thought these products should be available on NHS prescription for both NRT and bupropion (OR = 0.66, P < 0.05), which in turn was related to beliefs about whether smokers should have to pay for treatment themselves, the cost-effectiveness of NRT/bupropion and the low priority they would give NRT/bupropion in the drug budget. For bupropion, concern about side-effects independently predicted not prescribing [odds ratio (OR) = 1.46, P < 0.03]. CONCLUSION: In the British health-care system, which has a well-established system for technology assessment and professionally endorsed guidelines, a significant minority of GPs decline all patient requests for stop-smoking medicines.

Bupropion↗