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Biomedical subjects

Robert West

Publications and source records attributed to Robert West.

At least 19 recordsLinked to original sources
PubMed2007

A double-blind placebo-controlled experimental study of nicotine: II--Effects on response inhibition and executive functioning.

RATIONALE: Smokers may show abnormal functioning in prefrontal cortex during acute abstinence, reflecting deficient activity in mesocorticolimbic circuitry. Cognitive correlates of this putatively include impaired response inhibition and other aspects of executive functioning. OBJECTIVES: To investigate whether inhibitory control and other executive functions in smokers are impaired during acute abstinence relative to post-nicotine. METHODS: 145 smokers were tested twice after overnight abstinence-once after nicotine and once after placebo lozenges (order counterbalanced, double-blind)-on an antisaccade task, a continuous performance task (CPT), a delayed response spatial working memory task and a verbal fluency test. RESULTS: Compared with placebo, nicotine was associated with better inhibitory control on the antisaccade task and fewer impulsive responses to filler stimuli (motor errors) on the CPT; at the first assessment only, nicotine also reduced impulsive responses to 'catch' stimuli on the CPT. However, it did not affect CPT response bias (an index of impulsive vs cautious decision-making), spatial working memory, or verbal fluency. CONCLUSIONS: Smoking abstinence appears to be associated with a difficulty in inhibiting prepotent motor responses, and with nicotine to attenuate this difficulty. However, more 'cognitive' forms of inhibitory control (e.g. decision-making) and the other aspects of executive function tested here appear to be unaffected.

Adult↗
PubMed2007

Word-list-learning performance in younger and older adults: intra-individual performance variability and false memory.

We investigated the word-list-learning performance of younger and older adults over 4 consecutive days at different times of day to study age-related differences in consistency of performance over time and the influence of circadian variation on performance. Eighteen younger (M age, 23.4 years) and 18 older (M age, 73.3 years) men and women participated. The start time of testing alternated between morning and early evening across the 4 days of testing. On each test day, participants learned a different list of 15 unrelated words over four learning trials. As expected, younger adults performed better than older adults on immediate recall, delayed recall, and recognition. Contrary to our expectations, time of day did not significantly influence recall or recognition performance in either the older or younger adults. Older adults did show a greater incidence of false memory (i.e., previously learned list intrusions in free recall and false alarms in recognition) than younger adults. Older adults also exhibited greater intra-individual performance variability on the measures of false memory across test days. This variability was not related to circadian variation. False memory and variability of performance have both been linked to frontal systems dysfunction. The findings presented here are consistent with the notion that changes in cognition with aging in part reflect age-related decline in frontal lobe function.

Adult↗
PubMed2006

Eye movements and prospective memory: what the eyes can tell us about prospective memory.

In this study we used eye tracking methodology in combination with multi-element displays to examine the processes underlying event-based prospective memory in a visual search paradigm. In the task individuals searched for a different target stimulus (i.e., a letter) on each trial that could be present or absent, and made prospective responses to the letters D or M. The response accuracy data revealed that target hits were more frequent than prospective hits, and that there was no difference in response time for target and prospective responses. The eye tracking data revealed that both first and total fixation durations increased from distractors (stimuli that were neither targets nor prospective cues) to targets to prospective cues when a target or prospective response was made. These measures also revealed that the presence of a target in the display served to disrupt prospective memory. In addition, prospective memory misses resulted from a combination of failures to fixate the prospective cues and failures to engage in strategic processing of the prospective cues. These data demonstrate the utility of eye tracking methods in examining the processes underlying event-based prospective memory.

Analysis of Variance↗
PubMed2006

Solid-state (29)Si NMR study of RSiSiR: a tool for analyzing the nature of the Si-Si bond.

The first solid state 29Si NMR of a disilyne, that is, RSiSiR, R = Si(CH(SiMe3)2)2(i-Pr) (1) was measured: delta11 = 364 +/- 20; delta22 = 221 +/- 16 and delta33 = -350 +/- 13; CSA = -643 ppm. These measured values as well as calculations for model disilynes strongly support the description of the Si-Si bond in bent disilynes as a triple bond, although with weakened pi-bonds and a reduced bond order of 2.6.

Journal Article↗
PubMed2006

Gone but not forgotten: the effects of cancelled intentions on the neural correlates of prospective memory.

Event-related brain potentials (ERPs) were used to examine the neural correlates of the prospective interference effect and the effects of canceling an intention on the neural correlates of prospective memory. The response time data revealed a prospective interference effect that was associated with the engagement of prospective retrieval mode and item checking. The ERP data revealed that item checking was associated with sustained activity over the frontal and occipital-parietal regions of the scalp beginning at around 300 ms after stimulus onset. The ERP data also revealed that canceling an intention may have blocked the retrieval of the intention from memory when the prospective cue was encountered and led to a significant attenuation in the degree that the neural correlates of cue detection and post-retrieval processes were expressed.

Adolescent↗
PubMed2006

Tobacco control: present and future.

The history of tobacco control in the twentieth century can be summed up by the phrase 'too little, too late'. The century saw the proliferation of the most deadly form of tobacco use: cigarette smoking. Until the 1970s, no government took serious action to protect its citizens. In fact, probably the most effective global tobacco control 'strategies' to date have not been motivated by health concerns: they have been inaccessible or uneconomic markets for tobacco companies and a cultural taboo on women smoking. Economic development has led to massive increases in male cigarette smoking in developing countries but even now <10% of women in non-Western countries such as China, Russia and India smoke. With 'westernization', this picture is changing. Without drastic action to get current smokers to stop, the annual rate of tobacco-related deaths will grow from 5 million in 2006 to 10 million in 2025. Without further action to prevent take up of smoking, the subsequent death toll will be even higher. The recently enacted World Health Organization (WHO)-initiated Framework Convention on Tobacco Control (FCTC) can mitigate this impending disaster but only if it is implemented according to the spirit and not just the letter of the articles contained therein. Specific tobacco levies in every country should be the primary means of kick-starting the process, with the proceeds being used exclusively to fund other tobacco control initiatives, including product regulation.

Forecasting↗
PubMed2006

A double-blind placebo controlled experimental study of nicotine: I--effects on incentive motivation.

RATIONALE: Brain reward pathways implicated in addiction appear to be less reactive in regular drug users; behavioural manifestations may include decreased sensitivity to natural reinforcers. OBJECTIVES: This study aimed to replicate earlier findings of abstinence-associated incentive motivation deficits in smokers and to determine whether these can be reversed with nicotine in the form of lozenge. METHODS: One hundred forty-five smokers were each tested twice, once after receiving nicotine, and once after receiving placebo lozenge in counterbalanced order. Participants completed various tests of incentive motivational functioning: a measure of subjective enjoyment, the Snaith-Hamilton pleasure scale (SHAPS); a simple card sorting task, the card arranging reward responsivity objective test (CARROT) with and without financial incentive; the modified emotional Stroop test; a cue-reactivity task; and a novel reaction time task to explore effects of signals of reward, the incentive motivational enhancement of response speed task. RESULTS: Compared with performance during abstinence (placebo condition), nicotine was associated with: higher self-reported pleasure expectations on the SHAPS; enhanced responsiveness to financial reward on the CARROT in smokers who smoked 15 or more cigarettes a day; and greater interference from appetitive words on the Stroop task. CONCLUSIONS: These results are generally consistent with contemporary neurobiological theories of addiction and suggest that short-term smoking abstinence is associated with impaired reward motivation which can be reversed with nicotine.

Adult↗
PubMed2006

Bone morphogenetic protein antagonist gremlin 1 is widely expressed by cancer-associated stromal cells and can promote tumor cell proliferation.

Although tissue microenvironments play critical roles in epithelial development and tumorigenesis, the factors mediating these effects are poorly understood. In this work, we used a genomic approach to identify factors produced by cells in the microenvironment of basal cell carcinoma (BCC) of the skin, one of the most common human cancers. The global gene expression programs of stromal cell cultures derived from human BCCs showed consistent, systematic differences from those derived from nontumor skin. The gene most consistently expressed at a higher level in BCC tumor stromal cells compared with those from nontumor skin was GREMLIN 1, which encodes a secreted antagonist of the bone morphogenetic protein (BMP) pathway. BMPs and their antagonists are known to play a crucial role in stem and progenitor cell biology as regulators of the balance between expansion and differentiation. Consistent with the hypothesis that BMP antagonists might have a similar role in cancer, we found GREMLIN 1 expression in the stroma of human BCC tumors but not in normal skin in vivo. Furthermore, BMP 2 and 4 are expressed by BCC cells. Ex vivo, BMP inhibits, and Gremlin 1 promotes, proliferation of cultured BCC cells. We further found that GREMLIN 1 is expressed by stromal cells in many carcinomas but not in the corresponding normal tissue counterparts that we examined. Our data suggest that BMP antagonists may be important constituents of tumor stroma, providing a favorable microenvironment for cancer cell survival and expansion in many cancers.

Bone Morphogenetic Protein 2↗
PubMed2006

Prevention of relapse after quitting smoking: a systematic review of trials.

BACKGROUND: After initially successful quit attempts, many people return to smoking within a year, reducing the public health benefits of investment in smoking cessation. We aimed to assess whether interventions designed to prevent relapse after a successful quit attempt reduce the proportion of recent quitters who return to smoking. METHODS: We searched the Cochrane Tobacco Addiction Review Group trials' register. We selected randomized or quasi-randomized controlled trials of relapse prevention interventions with a minimum follow-up of 6 months. We included people who quit on their own, underwent enforced abstinence, or were in treatment programs. We included trials comparing relapse prevention interventions with no intervention or cessation plus relapse prevention with cessation intervention alone. Two of us independently extracted data from each report, with disagreements referred to a third author. RESULTS: Forty-two studies met the inclusion criteria. The most common interventions were skills training to identify and resolve tempting situations and extended treatment contact. A few studies tested pharmacotherapy. We separately analyzed studies that randomized abstainers and those that randomized participants before their quit date. Within subgroups of trials, pooled odds ratios ranged from 0.86 to 1.30, and in most analyses, 95% confidence intervals included 1. Most studies had limited power to detect moderate differences between interventions. CONCLUSION: The evidence to date does not support the adoption of skills training or other specific interventions to help individuals who have successfully quit smoking to avoid relapse, but this is an important area for future study.

Clinical Trials as Topic↗
PubMed2006

Randomized controlled trial of a social support ('buddy') intervention for smoking cessation.

OBJECTIVE: To assess the effectiveness of including a social support intervention ('buddy system') in a group treatment programme to aid smoking cessation. METHODS: Five hundred and sixty-three smokers attended groups at a smokers' clinic. These groups were randomized either to be (a) groups in which smokers were paired with another person to provide mutual support (buddy condition: n=237 in 14 groups) or (b) to receive the same treatment without the buddy component (control: n=326 in 20 groups). Participants were seen weekly for the first 4 weeks after stopping then followed up again after 26 weeks. RESULTS: Smokers in the buddy condition were no more likely than smokers in the control condition to stay abstinent at 1, 4 or 26 weeks. The effect was in the right direction at week one post-quit but after controlling for potential confounders the difference was not significant (odds ratio=1.45 (95% CI; 0.92-2.29), p=0.06). CONCLUSIONS: We were unable to show that a buddy system improved abstinence rates of group treatment programmes. This might be due to the high level of social support already achieved through the groups. PRACTICE IMPLICATIONS: The buddy system is a simple and very low cost addition to a group treatment programme; but the results from this study suggest that the kind of buddy system tested may not add substantially to the success rates. However there may be merits in a more intensive or protracted form of buddying.

Adult↗
PubMed2006

[Bis(trimethylsilyl)amido-kappaN]{tert-butyl[(E)-2-(tert-butylimino)ethyl]amido-kappa(2)N,N'}tin(II), a key intermediate in the synthesis of 1,3-di-tert-butyl-2,3-dihydro-1H-1,3,2-diazastannole.

The title compound, [Sn(C10H21N2)(C6H18NSi2)], contains the Sn(II) centre in a trigonal-pyramidal geometry. The basal plane is formed by three N atoms and the fourth apical position is occupied by a stereoactive lone pair. The Sn atom is displaced from the plane of the three N atoms by 1.1968 (12) A. The Sn-N bonds are highly polarized toward the N atoms, as confirmed by natural bonding orbital analysis.

Journal Article↗
PubMed2006

Effectiveness of specialist group treatment for smoking cessation vs. one-to-one treatment in primary care.

OBJECTIVE: Using a quasi-experimental design, this paper contributes to an important debate about the most effective form of psychological treatment to aid smoking cessation: group treatment provided by specialists or one-to-one treatment provided in the community by primary care nurses or pharmacists. METHODS: Data were routinely collected from 1501 clients of a large London stop smoking service that offered both group and one-to-one treatment. RESULTS: A quarter (25%) of the clients were continuously abstinent 4 weeks post-quit: 30% for those receiving group treatment and 19% for one-to-one (Fisher's exact [2-sided]<.001). The difference between the specialist and community-based treatment remained after all possible confounding factors were controlled for (OR: 2.27, p<.001). CONCLUSIONS: In the same service with the same management structure and training programme, group treatment offered by the specialist service yielded higher success rates than counselling by trained primary care nurses and pharmacists.

Adult↗
PubMed2006

"Catastrophic" pathways to smoking cessation: findings from national survey.

OBJECTIVE: To assess the extent to which the prevailing model of smoking cessation (that smokers typically prepare their attempts to stop smoking in advance and that doing so increases their chances of success) is correct. DESIGN: Cross sectional household survey. SETTING: England. PARTICIPANTS: 918 smokers who reported having made at least one quit attempt and 996 ex-smokers aged 16 and over. MAIN OUTCOME MEASURES: Whether the most recent quit attempt was planned in advance and whether quit attempts made at least six months before resulted in at least six months' abstinence. RESULTS: 48.6% of smokers reported that their most recent quit attempt was put into effect immediately the decision to quit was made. Unplanned quit attempts were more likely to succeed for at least six months: among respondents who had made a quit attempt between six months and five years previously the odds of success were 2.6 times higher (95% confidence interval 1.9 to 3.6) in unplanned attempts than in planned attempts; in quit attempts made 6-12 months previously the corresponding figure was 2.5 (1.4 to 4.7). The differences remained after controlling for age, sex, and socioeconomic group. CONCLUSIONS: A model of the process of change based on "catastrophe theory" is proposed, in which smokers have varying levels of motivational "tension" to stop and then "triggers" in the environment result in a switch in motivational state. If that switch involves immediate renunciation of cigarettes, this can signal a more complete transformation than if it involves a plan to quit at some future point.

Adolescent↗
PubMed2006

Acute effect of isometric exercise on desire to smoke and tobacco withdrawal symptoms.

A brief bout of aerobic exercise (e.g. stationary bicycle) has been shown to result in an acute reduction in tobacco withdrawal symptoms and cravings in abstinent smokers. However, aerobic exercise is often not practical and it is of interest to examine whether non-aerobic exercise has a similar effect. We investigated whether isometric exercise (involving muscular contractions against resistance without movement, e.g. placing the palms of the hands together and pushing) reduces desire to smoke and tobacco withdrawal symptoms. Following overnight abstinence smokers were randomized to 5-min of: isometric exercises (n = 20), body scanning (focusing attention on sensations in different areas of the body, n = 20, control), or sitting passively (n = 20, control). Desire to smoke and tobacco withdrawal symptoms ('irritable', 'depressed', 'stressed', 'tense', 'restless' and 'poor concentration') were rated at baseline, immediately post-intervention, and 5-, 10-, 15- and 20-min post-intervention. Isometric exercise produced a significantly greater reduction in desire to smoke versus passive control at immediate post-intervention and 5-min post-intervention, relative to baseline (p < 0.05). Most withdrawal symptoms were significantly moderated by exercise versus controls at some point between 5- to 20-min post-intervention, relative to baseline (p < 0.05). Brief isometric exercise has potential for offering immediate relief from a desire to smoke.

Adolescent↗
PubMed2006

The influence of aging and frontal function on the neural correlates of regulative and evaluative aspects of cognitive control.

The influence of aging and frontal function on the neural correlates of regulative and evaluative control was examined by means of event-related brain potentials (ERPs). The behavioral data indicated that interference was greater for older than for younger adults and that this difference was mediated by frontal function. The ERP data revealed effects of aging on the neural correlates of both regulative and evaluative control. Prestimulus neural activity was correlated with response time and frontal function, and these relationships were moderated by the response-to-stimulus interval (RSI); the poststimulus data also revealed age-related differences in the neural correlates of evaluative control that interacted with RSI. These data support predictions derived from the context processing deficit theory of aging.

Adult↗
PubMed2006

Pathways, networks and choice in health care.

PURPOSE: The purpose of the paper is to present an alternative to the supply chain model of health care delivery that currently informs most thinking about the design of care processes. DESIGN/METHODOLOGY/APPROACH: The paper draws on arguments from systems theories and public administration, to generate an analysis of the nature of health care processes. It sets out a model of services characterised by treatment and care needs that vary over time, that are inherently uncertain, involve frequent assessment and re-assessment, and provide patients and service providers with choices about treatment and care. Evidence from an evaluation of intermediate care is used to illustrate the analysis. FINDINGS: The analysis suggests that both the supply chain and a more network-like model of health care processes can help us to understand health care processes. The two are complementary. RESEARCH LIMITATIONS/IMPLICATIONS: Largely conceptual in nature. The empirical evidence is taken from one study. The ideas are presented to stimulate thinking rather than to prove an argument. PRACTICAL IMPLICATIONS: The conceptualisation of care processes as network-like has implications for the way in which we think about the design and performance of health care systems. ORIGINALITY/VALUE: There have been few publications that seek to use both systems and network approaches to understand health care processes.

Delivery of Health Care, Integrated↗
PubMed2006

It is about people.

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Behavior, Addictive↗