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Biomedical subjects

Robert West

Publications and source records attributed to Robert West.

At least 73 records · Page 4Linked to original sources
PubMed2004

Acute effect of a brief bout of exercise on alcohol urges.

AIM: To examine whether a brief bout of moderate intensity exercise reduces alcohol urges and mood disturbance in those with alcohol dependence. DESIGN: A counterbalanced cross-over design (within-subjects). SETTING: A hospital-based alcohol rehabilitation clinic. PARTICIPANTS: Twenty males and females [mean (SD) age = 40.1 (8.2) years, mean (SD) Severity of Alcohol Dependence Questionnaire score = 34.2 (13.4)] who had recently completed alcohol detoxification [mean (SD) days since completing detoxification = 3.5 (2.3)]. INTERVENTION: On the first day of experimentation all participants (N = 20) were randomized to undergo one of two conditions, either: (i) a single bout of 10 minutes of moderate intensity cycling (experimental), or (ii) a single bout of 10 minutes of very light intensity cycling (control). On the following day they underwent the remaining condition. MEASUREMENTS: All participants completed the Alcohol Urge Questionnaire and a six-item measure of mood disturbance at the following times: (i) immediately before exercise (baseline), (ii) during exercise (at 5 minutes), (iii) immediately following exercise, (iv) 5 minutes following exercise and (v) 10 minutes after exercise. FINDINGS: Relative to baseline, there was a significant decline in alcohol urges for the experimental condition versus control during exercise (P = 0.02) but not at any measurement point following exercise. At baseline, by chance, there was a non-significant tendency for there to be higher ratings of alcohol urges for the experimental condition versus the control. For mood, there was no evidence for significant differences between treatment conditions for baseline versus any subsequent measurement point. CONCLUSIONS: A brief bout of moderate intensity exercise may provide some short-term relief from alcohol urges during exercise. Further studies are required to replicate the present findings and to confirm whether any moderating effect of exercise on alcohol urges is sustained following exercise.

Adult↗
PubMed2004

Sensitivity of medial frontal cortex to response and nonresponse conflict.

The anterior cingulate cortex (ACC) holds a prominent place in models of the neural architecture supporting cognitive control and conflict processing. The findings of empirical and computational work lead to the prediction that the ACC is sensitive to response conflict and insensitive to nonresponse conflict. We tested this prediction in two experiments using event-related brain potentials in combination with a task in which some trials included only nonresponse conflict and others included nonresponse and response conflict. A N450 associated with the activity of neural generators in the ACC and anterior frontal region was elicited on trials including only nonresponse and nonresponse and response conflict. This finding is inconsistent with the hypothesis that activation of the ACC is limited to response conflict and may identify one avenue of development in future applications of conflict theory.

Adult↗
PubMed2004

Is detecting prospective cues the same as selecting targets? An ERP study.

Prospective memory represents our ability to realize intentions that must be delayed for some period of time. In this study, we examined modulations of the event-related brain potentials (ERPs) associated with target selection in visual working memory and prospective-cue detection in prospective memory. Targets and prospective cues elicited an N2pc, indicating that a common neural mechanism supports selection in working memory and prospective memory. Partial least squares analysis revealed that the N300 and prospective positivity were associated with a latent variable that contrasted the ERPs elicited by prospective-cue trials with those elicited by target-present and target-absent trials, in agreement with the idea that these modulations of the ERPs are uniquely related to prospective memory.

Adolescent↗
PubMed2003

PML-RARA-targeted DNA vaccine induces protective immunity in a mouse model of leukemia.

Despite improved molecular characterization of malignancies and development of targeted therapies, acute leukemia is not curable and few patients survive more than 10 years after diagnosis. Recently, combinations of different therapeutic strategies (based on mechanisms of apoptosis, differentiation and cytotoxicity) have significantly increased survival. To further improve outcome, we studied the potential efficacy of boosting the patient's immune response using specific immunotherapy. In an animal model of acute promyelocytic leukemia, we developed a DNA-based vaccine by fusing the human promyelocytic leukemia-retinoic acid receptor-alpha (PML-RARA) oncogene to tetanus fragment C (FrC) sequences. We show for the first time that a DNA vaccine specifically targeted to an oncoprotein can have a pronounced effect on survival, both alone and when combined with all-trans retinoic acid (ATRA). The survival advantage is concomitant with time-dependent antibody production and an increase in interferon-gamma (IFN-gamma). We also show that ATRA therapy on its own triggers an immune response in this model. When DNA vaccination and conventional ATRA therapy are combined, they induce protective immune responses against leukemia progression in mice and may provide a new approach to improve clinical outcome in human leukemia.

Animals↗
PubMed2003

Bis[bis(trimethylsilyl)amino]silylene, an unstable divalent silicon compound.

The title compound, [(Me3Si)2N]2Si: (1), was prepared by the reduction of [(Me3Si)2N]2SiBr2 (2) with potassium graphite at -78 degrees C. Unlike the corresponding germanium and tin compounds, 1 is unstable, but it can be studied in solution at low temperatures. The 29Si NMR chemical shift of 1 measured at -20 degrees C was 223.9 ppm, in good agreement with a value obtained from model calculations of 233 ppm. Reaction of solutions of 1 with methanol or phenol gave the trapping products expected for the silylene, [(Me3Si)2N]2Si(H)OR (R = CH3, C6H5).

Journal Article↗
PubMed2003

A disilapentalene and a stable diradical from the reaction of a dilithiosilole with a dichlorocyclopropene.

The reaction of 1,1-dilithio-2,3,4,5-tetraphenylsilole (1) with 1,1-dichloro-2,3-diphenylcyclopropene (2) leads to the novel 1,4-disila-1,4-dihydropentalene (4), as well as an exceptionally stable diradical for which the structure 3 is suggested. The diradical is unreactive toward water, methanol, and chloroform; upon heating it transforms into 4. Structure 3 for the paramagnetic species is proposed on the basis of EPR data and theoretical calculations. The trans-trans isomer of diradical 3 was calculated to be more stable than its cis-cis isomer. The strong and stable EPR signal in the reaction mixture is probably due to the trans-trans isomer of diradical 3 in the triplet state. A reaction scheme describing the formation of 3 and 4 is presented.

Journal Article↗
PubMed2003

Diurnal variations in first lapses to smoking for nicotine patch users.

Amongst those not using nicotine replacement therapy (NRT), first lapses to smoking have been shown to be more common in the afternoons and evenings than the mornings. The present study investigated whether first lapses amongst those using 16 h nicotine patches follow a similar pattern. This is of interest because 16 h patches may not provide sufficient nicotine early in the morning to meet the needs of smokers. 200 male and female smokers attended a cessation programme combining behavioural support and 16 h nicotine patches. During the first 2 weeks of smoking abstinence 70 smokers reported first lapses. The frequency of first lapses was significantly higher in the afternoons (12.00-18.00 h, 30 lapses) and evenings (18.00-24.00, 35 lapses) than in the mornings (24.00-12.00, five lapses, p < 0.001 for both comparisons). There was no detectable difference between the rates of first lapse in the afternoon and evening. In conclusion, abstaining smokers using 16 h nicotine patches are more likely to experience their first lapse in the afternoon or evening rather than in the morning. Despite nicotine patches providing limited nicotine replacement for the first few hours after waking, there is no evidence that this undermines quit attempts by failing to prevent lapses during that time.

Administration, Cutaneous↗
PubMed2003

Neural correlates of cognitive control and conflict detection in the Stroop and digit-location tasks.

In two experiments, event-related brain potentials were used to examine the neural correlates of cognitive control and conflict processing in the Stroop and digit-location tasks. The relevant dimension was cued on a trial-by-trial basis before stimulus onset. This method allows one to dissociate modulations of the event-related brain potentials (ERPs) associated with cognitive control from modulations of the ERPs associated with conflict processing that are temporally confounded in the standard Stroop task. Cognitive control was associated with a slow wave over the occipital-parietal region that differentiated goal-compatible from goal-incompatible responses in both the Stroop and digit-location tasks. Conflict processing was associated with a N450, in the Stroop task, and a conflict sustained potential (SP) in both tasks. The amplitude of the N450 was similar for color naming and word reading trials. The character of the conflict SP varied over the frontal and central-parietal regions. Over the left lateral frontal region the conflict SP was similar in amplitude across type of response in the Stroop and digit-location tasks. Over the right lateral frontal region the conflict SP was greater in amplitude for the less dominant stimulus dimension (i.e. color or digit). The findings of these experiments clearly demonstrate that different neural systems support cognitive control and conflict processing, with some degree of hemispheric specialization observed for conflict processing.

Adolescent↗
PubMed2003

To blow or not to blow: a randomised controlled trial of compression-only and standard telephone CPR instructions in simulated cardiac arrest.

This randomised controlled trial used a manikin model of cardiac arrest to compare skill performance in untrained lay persons randomised to receive either compression-only telephone CPR (Compression-only tel., n=29) or standard telephone CPR instructions (Standard tel., n=30). Performance was evaluated during standardised 10 min cardiac arrest simulations using a video recording and data from a laptop computer connected to the training manikin. A number of subjects in both groups did not open the airway. More than 75% in the Standard tel. group failed to deliver two effective initial rescue breaths, and only 17% provided an adequate inflation volume for subsequent breaths, delivering a median of only five inflations during the entire scenario. Most subjects in both groups gave chest compressions that were too shallow and at an inappropriately rapid rate. Hand position was also poor, but was worse in the group given simplified instructions. There was a significant delay to first compression in both groups, although this interval was shortened by over a minute when ventilations were eliminated from the telephone instruction algorithm (245 vs. 184 s, P<0.001). Over two-and-a-half times as many chest compressions were delivered during an average ambulance response time with compression-only telephone directions compared with standard CPR (461 vs. 186, P<0.001). These variables may be critical in predicting survival from out-of-hospital cardiac arrest. Further research is necessary to establish if modifications to scripted telephone instructions can remedy the identified performance deficiencies. Eliminating instructions for rescue breaths from scripted telephone directions will have little impact on the ventilation of most patients. Research is required to determine if the consequent reduction in the delay to starting chest compressions and the significant increase in the number of compressions delivered can increase survival from out-of-hospital cardiac arrest.

Adult↗
PubMed2003

The use of videos to inform smokers about different nicotine replacement products.

This study examined the feasibility of using video presentations to inform smokers about nicotine replacement treatment (NRT). The study was part of a larger trial comparing four different NRTs. Five hundred and four smokers attended a clinic on the day they stopped smoking. They were presented with a brief video overview of the four treatments. They were then randomly allocated to a treatment and shown another brief video describing that treatment in more detail. After 1 week of NRT use, participants rated how clearly the video described how the treatments work, how to use them and their possible side effects. They also rated how their experience of the product compared to expectation in terms of helpfulness, convenience and side effects. The smokers reported overwhelmingly that the videos had accurately described the product to which they had been allocated. Video presentations can be an effective way to convey information to smokers about NRT.

Adult↗
PubMed2003

Neurophysiological evidence for disturbances of conflict processing in patients with schizophrenia.

Deficits in cognition are a hallmark of schizophrenia. In the present study, the authors investigated the effects of schizophrenia on the neural correlates of conflict processing in a single-trial version of the Stroop task by using event-related brain potentials. Relative to matched controls, patients with schizophrenia showed increased Stroop interference in response time, but this effect was eliminated when the effect of response slowing was controlled. In controls, conflict processing was associated with a negative wave peaking between 400 and 500 ms (N450) and conflict sustained potential (SP) peaking between 600 and 800 ms after stimulus onset. In patients with schizophrenia, the amplitude of the N450 was significantly attenuated and the conflict SP was absent. These results provide evidence for the existence of altered neural processes associated with conflict processing that may be associated with dysfunction of the anterior cingulate and prefrontal cortex in patients with schizophrenia.

Adult↗
PubMed2003

Neural correlates of age-related declines in the formation and realization of delayed intentions.

Neural correlates of age-related declines in prospective memory were studied by using event-related brain potentials (ERPs) in a task in which individuals formed and later realized simple intentions. The behavioral data revealed that prospective responding was less accurate and slower in older than in younger adults. The electrophysiological data revealed age-related differences in the amplitude of modulations of the ERPs associated with the encoding of intentions, the detection of cues, and disengagement from the ongoing activity. These findings support the hypothesis that age-related declines in prospective memory result from a reduction in the efficiency with which older adults encode intentions and detect cues.

Adolescent↗
PubMed2003

Efficacy of exercise counselling as an aid for smoking cessation: a randomized controlled trial.

AIM: To examine whether exercise counselling increases smoking abstinence and reduces tobacco withdrawal and gains in weight and body fat. DESIGN: A randomized controlled trial. SETTING: A community-based stop smoking clinic. PARTICIPANTS: Two hundred and ninety-nine male and female smokers. INTERVENTION: Participants were assigned randomly to a 7-week smoking cessation programme, including nicotine replacement therapy plus either (i) exercise counselling, or (ii) health education advice with equal contact time as for the exercise counselling condition. MEASUREMENTS: Six weeks of smoking abstinence was confirmed by expired carbon monoxide. FINDINGS: There was no significant difference in smoking abstinence between the exercise group (n = 154) and the controls (n = 145) at 6 weeks (39.6% versus 38.6%), nor was there any difference in gains in weight or body fat, although those in the exercise group increased their exercise levels. Exercise participants reported less tension, anxiety and stress than the controls during the first week of smoking abstinence (P = 0.03, 0.01 and 0.04, respectively), less irritability throughout 2 weeks of abstinence (P = 0.03), and less restlessness throughout 3 weeks of abstinence (P = 0.04). CONCLUSIONS: Adding brief exercise counselling to a smoking cessation programme did not increase smoking abstinence or reduce gains in weight or body fat significantly, although exercise levels were raised and there were some beneficial effects on psychological symptoms.

Adult↗
PubMed2003

Effects of intention load and background context on prospective remembering: an event-related brain potential study.

Prospective remembering reflects the ability to realize intentions that must be delayed over some period of time. Recent evidence indicates that distinct modulations of the event-related brain potentials may be associated with the detection of a prospective memory cue (N300) and the recovery of an intention from memory (LPC, slow wave). The present experiments examined the degree to which these modulations were influenced by task manipulations that were expected to differentially influence cue detection and memory-related processes. Varying the number of intentions modulated the amplitude of a slow wave that may reflect memory-related processes. In contrast, varying the distinctiveness of the cues modulated the N300 and the early portion of the LPC indicating that this manipulation primarily influenced detection and categorization processes. These findings indicate that the N300, LPC and slow wave reflect functionally distinct processes associated with prospective memory.

Adolescent↗
PubMed2003

Bupropion SR for smoking cessation.

Cigarette dependence is recognised as a life-threatening disorder which can be treated by behavioural support and/or medication. Bupropion hydrochloride sustained-release (Zyban trade mark, GlaxoSmithKline) is licensed in many countries including the US, Canada, UK, Australia and continental Europe to aid smoking cessation. The usual recommended dose is 150 mg b.i.d. taken for 7 - 14 days prior to the quit date, and then 6 - 8 weeks afterwards (figures vary across countries). Evidence from seven double-blind, placebo-controlled, randomised trials shows that it improves success at staying off cigarettes for at least 12 months by 9 - 10 percentage points. Taking into account estimates of subsequent cessation and relapse patterns in treated and untreated smokers, and the improvement in life-expectancy of smokers who manage to stop, the estimated cost/life/year saved from an episode of use of the medication is approximately UK pound 1000 or US$1500. Bupropion has CNS stimulant properties; the common side effects are dry mouth and sleep disturbance. Rare but serious side effects are anaphylactic/hypersensitivity reaction and seizure (both estimated at 1 in a 1000). The drug is contraindicated in patients with hypersensitivity to the drug or its metabolites, any seizure disorder, eating disorder, severe hepatic cirrhosis, history of bipolar disorder or in patients taking monoamine oxidase inhibitors. Extreme caution is advised where there are any predisposing factors that may reduce the seizure threshold. Bupropion sustained-release and nicotine replacement therapies are both considered as first-line treatments to aid smoking cessation. Ideally patients should also enrol in a structured behavioural support programme to boost their chances of success.

Bupropion↗