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Biomedical subjects

A Mathews

Publications and source records attributed to A Mathews.

At least 37 records · Page 2Linked to original sources
PubMed1990

Effects of stress and anxiety on the processing of threat stimuli.

Two experiments extended the work of MacLeod and Mathews (1988) and examined whether a cognitive bias for threat information is a function of state or trait anxiety. Color-naming and attention deployment tasks were used to assess the effects of a stress manipulation procedure on attentional responses in high and low trait anxious subjects. Subjects under high stress selectively allocated processing resources toward threat stimuli, irrespective of their trait anxiety level. There was no consistent evidence of a cognitive bias associated with trait anxiety, and the effect of the stress manipulation did not appear to be mediated by state anxiety. It was suggested that trait factors do not modify attentional biases associated with acute stress, but may influence such biases when stress is prolonged.

Adult↗
PubMed1990

Aerobic fitness, physical activity, and psychophysiological reactions to mental tasks.

The association between aerobic fitness, exercise, and psychophysiological reactivity was assessed in cross-sectional and prospective analyses. Seventy-five healthy but sedentary adults carried out a sub-maximal exercise test and easy and difficult problem solving tasks. Blood pressure, heart rate, skin conductance level, respiration rate, tidal volume, and oxygen consumption were monitored and additional heart rate was also computed. Differences between relatively fit and unfit individuals were found in respiration rate during tasks and in skin conductance level during post-task recovery periods, with a tendency toward diminished heart rate reactivity in fitter people. Subjects were subsequently allocated to four conditions: high intensity aerobic training, moderate intensity aerobic training, an undemanding strength and flexibility program (designed as an attention-placebo condition), and waiting list control. Training programs were conducted over a 10-week period, and were followed by a second laboratory session. Appropriate changes in aerobic performance over the training period were observed in the 12-min run/walk test. There were no important modifications in psychophysiological stress reactions associated with the different experimental conditions. These results are discussed in relation to the literature concerning the effects of fitness and physical activity on physiological response patterns.

Adult↗
PubMed1989

Selective processing of threat cues in anxiety states: a replication.

A replication of Mathews and MacLeod's (Behav. Res. Ther. 23, 563-569, 1985) study, using a modified Stroop task, confirmed that threat words selectively interfere with the colour-naming performance of generally anxious patients, compared with normal controls. Clearer evidence was obtained of a highly specific interference effect of threat words that were congruent with the predominant worries reported by anxious patients. However, there was no evidence of a subsequent recognition memory bias for the threat words in anxious Ss. These results are discussed in relation to findings from other recent experiments investigating attentional and memory biases for threat-related information in anxiety states, and their implications for cognitive theories of anxiety are considered.

Adult↗
PubMed1989

The effects of exercise training on mood and perceived coping ability in anxious adults from the general population.

A comparison was carried out of the psychological effects of a moderate aerobic training programme (n = 24) and an attention-placebo strength and flexibility training programme (n = 23) in previously inactive anxious adults from the general population. Training consisted of one supervised and three unsupervised sessions per week for 10 weeks. Effects were assessed with the Profile of Mood States, the State-Trait Anxiety Inventory and questionnaires indexing perceived coping ability. Seven participants dropped out of each condition during the training period. Expectations of benefit assessed pre-training, and satisfaction assessed post-training, did not differ between conditions. The moderate exercise programme led to significant improvements in aerobic fitness, and was associated with significantly greater reductions in tension-anxiety, depression and other moods than the attention-placebo condition, together with increases in perceived ability to cope with stress. Psychological responses were not correlated with changes in fitness assessed with bicycle ergometry or the 12 min walk/run test. These effects were maintained on 3 month follow up.

Adaptation, Psychological↗
PubMed1989

The effects of exercise training on mental well-being in the normal population: a controlled trial.

This study was designed to compare the effects of two aerobic training programmes of differing intensities on mood and mental well-being with those of a credible attention-placebo condition. One hundred and nine sedentary adult volunteers from the local population were assigned to four conditions: high intensity aerobic training, moderate intensity aerobic training, attention-placebo and waiting list. Training was carried out over a 10 week period. Subjects were assessed before and after training with psychological measures and the 12 min walk-run test, and follow-up evaluations were undertaken after 3 months. Ninety-four subjects began the programme and the adherence rate averaged 80%, with no significant differences in number of drop-outs between conditions. Appropriate changes in estimated maximum oxygen consumption were observed in the three active conditions with the 12 min walk-run test. Psychological benefits were seen with the moderate exercise condition but not in the high exercise or attention-placebo conditions. These effects were manifest immediately after training on measures of tension/anxiety and confusion, and at follow-up on measures of perceived coping ability. The mechanisms underlying this pattern of results are discussed and the relative importance for health of vigorous activity and physical fitness is considered.

Adaptation, Psychological↗
PubMed1989

Interpretation of homophones related to threat in anxiety states.

In previous studies, we have established that anxiety states are characterized by an attentional bias that favors the processing of threatening stimuli. In the present study we extend this finding to ambiguous stimuli, specifically, homophones with spellings that correspond to either a threatening or a neutral meaning. As predicted, clinically anxious subjects used the threatening spellings relatively more than did controls, whereas recovered subjects were intermediate in this respect. Threatening words were associated with greater skin conductance responses than were neutral words, but the groups did not differ in their electrodermal reactions to homophones. We take these findings as evidence that, although the different meanings of ambiguous stimuli may be processed in parallel by all subjects, an interpretive bias operates such that anxiety-prone individuals tend to become preferentially aware of the more threatening meaning of such events.

Anxiety Disorders↗
PubMed1989

Implicit and explicit memory bias in anxiety.

Previous investigations of recall and recognition for threatening information in clinically anxious subjects have yielded equivocal results. The present study contrasts implicit (word completion) with explicit (cued recall) memory and shows that indices of bias for emotional material derived from the two types of memory are independent of one another. The explicit measure was correlated with trait anxiety scores, but did not clearly distinguish between subjects with clinical anxiety states and normal control subjects. On the implicit memory measure, clinically anxious subjects produced more threat word completions, but only from a set to which they had recently been exposed. These results are taken as evidence that internal representations of threat words are more readily or more persistently activated in anxiety states, although they are not necessarily better elaborated.

Adult↗
PubMed1988

Quantitative and qualitative assessment of serum concentration monitoring and dosage adjustment of aminoglycosides.

A prospective study was carried out in 50 adult patients to determine the extent and quality of aminoglycoside serum concentration monitoring and dosage adjustment in a U.K. teaching hospital. Data were collected concerning prescription details, assay results, and subsequent dosage adjustment, methods of dosage determination, and timing of samples. Thirty-three patients received aminoglycosides without a positive culture. The mean +/- SD initial doses were 1.75 +/- 0.45 mg/kg for gentamicin and 2.33 +/- 0.55 mg/kg for netilmicin. Doses were derived from physicians' personal experience for 35 patients and using nomograms for 11 patients. Prescribed and actual administration times were observed on 218 occasions. The difference between these times were significantly different (p less than 0.005). Fifty-six trough, 61 peak, and 61 random assays were carried out, of which 48% of troughs and 56% of peaks were in the therapeutic range. Dosage regimens were calculated based on actual serum concentration assay results using the Sawchuk-Zaske method. These calculated doses were compared to actual prescribed doses for each patient. The calculated doses were greater than 120% of the prescribed doses in 78% of patients. There was a significant tendency to underdose (p = 0.001). It is concluded that the service might benefit from an individualised approach to dosage determination.

Adolescent↗
PubMed1987

Clinical pharmacokinetics, toxicity and cost effectiveness analysis of aminoglycosides and aminoglycoside dosing services.

This article reviews the clinical pharmacokinetics, clinical toxicity and cost-effectiveness analysis of aminoglycosides and of dosing services for aminoglycosides. The reader is referred elsewhere for a review of the pharmacology, antimicrobial spectrum of activity and clinical use of these drugs. A critique of the more commonly used methods of aminoglycoside dosage determinations is included, based on the inter-individual variation in aminoglycoside disposition parameters. The advantages and disadvantages of arbitrary, predictive, and pharmacokinetic methods of dosing determination are summarized. Justification for the routine determination of serum aminoglycoside concentrations is reviewed. We review the lack of standardization of definitions for aminoglycoside-associated nephrotoxicity in published studies, and studies which illustrate these differences are highlighted. Evidence for the association between serum aminoglycoside concentrations and nephrotoxicity is examined. Ototoxicity is similarly reviewed. The concept of cost-effectiveness analysis is examined extensively in this review. We discuss the literature concerning the cost benefit analysis of drug dosing services.

Amikacin↗