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Biomedical subjects

P Salmon

Publications and source records attributed to P Salmon.

At least 19 recordsLinked to original sources
PubMed1992

Contingent and non-contingent biofeedback training for Type A and B healthy adults: can Type As relax by competing?

This paper investigates an alternative approach to the modification of cardiovascular reactivity in healthy Type A adults using contingent (true) and non-contingent (false) heart rate biofeedback. Sixteen Type A and sixteen Type B subjects were either given instructions to compete for heart rate reduction or were given no competitive instructions. There were four relaxation sessions. In one, subjects were given contingent heart rate biofeedback and in another they were given no feedback. In two sessions 'feedback' was non-contingent: in one condition feedback suggested that heart rate decreased across the session; in the other the suggestion was of increase. Results showed that overall, biofeedback was an effective method for heart rate reduction but non-contingent feedback (decreased heart rate) was found to be as effective as contingent feedback. Overall, Type A subjects reduced heart rate significantly more than Type Bs. More importantly, Type As reduced heart rate significantly more when competing than when competition was not mentioned. These results suggest that core elements of Type A behaviour, in particular competition, could be exploited in the modification of physiological hyperactivity in healthy Type A individuals.

Adaptation, Psychological↗
PubMed1992

Multidimensional assessment of women's experience of childbirth: relationship to obstetric procedure, antenatal preparation and obstetric history.

Primiparous postnatal patients (N = 110) rated their experience of childbirth on a 20-item questionnaire based on an earlier survey of women's spontaneous descriptions. Principal components analysis of the ratings identified three independent dimensions, describing feelings of fulfillment, distress and difficulty, respectively. Ratings by 104 primiparous antenatal patients in the third trimester yielded similar dimensions. The postnatal sample was divided, in turn, according to obstetric procedure at delivery, antenatal classes attended, whether the present pregnancy was planned and history of previous termination. Their experience of childbirth was compared on each dimension. Forceps and unassisted deliveries were experienced similarly. Caesarian section was a less difficult, but also less fulfilling and more distressing, experience than either of these. Delivery was less distressing in those who attended antenatal classes, but only one type of class was associated with more fulfilling birth. Finally, delivery was more distressing in women whose pregnancy was unplanned, or in whom a previous pregnancy had been terminated. Future controlled investigations will be incomplete unless each of the three dimensions is measured.

Adult↗
PubMed1992

Unusual amino acid sequence of the second Ig-like domain of the feline CD4 protein.

We have cloned and sequenced the cDNA for cat CD4. The overall amino-acid sequence of cat CD4 is similar to that from the primate and rodent CD4 molecules, with a 58% identity between the cat and human sequences. Comparison to the crystal structure of human CD4 does, however, reveal unusual features in the second Ig-like domain, D2, of cat CD4. First, a reciprocal substitution between a tryptophan and a cysteine, this latter involved in an intrasheet disulfide bond of human D2, is predicted to generate an intrastrand disulfide bond, a feature rarely observed in an Ig-fold. Second, a large serine-threonine-rich insertion is found between the A and B beta strands of D2. This sequence is a potential O-linked glycosylation site, and should protrude in a region that appears flexible in human CD4. This unusual insertion could affect the interaction of cat CD4 with class II molecules, or with FIV, a feline homolog of HIV. The expression of cat CD4 in different environment, or of a mutated human CD4 carrying the cat insertion, should help in understanding the role of cat CD4 as a putative receptor for FIV, and the CD4/MHC class II interaction.

Amino Acid Sequence↗
PubMed1992

Recovery from minor abdominal surgery: a preliminary attempt to separate anxiety and coping.

Using bivariate and canonical correlations, we investigated the dimensionality and post-operative correlates of indices which, we suggested, could be related to active cognitive coping in 40 patients undergoing minor abdominal surgery. Trait anxiety and pre-operative state anxiety were also measured; these intercorrelated, but each was independent of the putative coping measures. There were, however, intercorrelations amongst these questionnaires, which included the 'worry' scale of a coping checklist, Type A personality, pre-operative arousal and, in a negative direction, 'powerful others' health locus of control and pre-operative stress. The dissociation between anxiety and the remaining measures emerged also in the post-operative correlates of these two dimensions. Whereas anxiety predicted poorer self-rated bodily state on the first post-operative day, the coping measures predicted a better state seven days post-operatively.

Adaptation, Psychological↗
PubMed1992

Cognitive outcome after cardiac operations. Relationship to intraoperative computerized electroencephalographic data.

Cardiopulmonary bypass frequently causes new postoperative neuropsychologic deficits. To assess whether these deficits could be predicted or limited, we monitored 29 patients receiving bypass intraoperatively with an on-line computerized electroencephalograph. We hypothesized that the 15 patients whose cerebral perfusion pressure was adjusted on the basis of this electroencephalographic data would have fewer postoperative deficits than the 14 patients whose pressure was monitored on the basis of systemic pressure. The results showed that new postoperative cognitive deficits in both groups were less prevalent than in previous studies, but there was not a significant difference in outcomes between the two groups. The intraoperative electroencephalographic records correlated with surgical, but not neuropsychologic, outcome. It is concluded that careful attention to intraoperative cerebral perfusion pressure may decrease the prevalence of postoperative neuropsychologic complications, but that the use of a computerized electroencephalograph does not necessarily contribute to an improved outcome.

Adult↗
PubMed1991

Sympathoadrenal effects on extinction of rewarded running in the rat.

Two groups of rats underwent adrenal demedullation or sham surgery before being trained to run in a straight runaway for food reward at a short intertrial interval (90 s). Half of each group of animals were then injected IP with the sympathetic neurotoxin, 6-hydroxydopamine HBr (6-OHDA; 30 mg/kg); the remainder received saline vehicle. After 3 more days of acquisition training, running was extinguished over 12 trials in all rats. Running times were similar in all groups at the start of extinction. In saline-injected animals, extinction proceeded more slowly in the demedullated than in the sham-operated group, but this effect was largely abolished by 6-OHDA. Consistent with previous results, there was evidence that 6-OHDA facilitated extinction, irrespective of adrenal demedullation, but this effect was most apparent in the time taken to emerge from the start-box. The rats were killed two days after the end of the experiment; cardiac noradrenaline levels were depleted by 83% of control values in 6-OHDA-treated animals. The results suggest that the adrenal medulla and sympathetic neurones have opposing and interacting effects on the response to nonreward.

Adrenal Glands↗
PubMed1991

Anxiolytic-like action of beta-blockers: effects of stimulus salience.

Eighteen rats were trained on a multiple schedule: lever pressing was rewarded on a Variable Interval (VI 20 s) in both components but, in addition, punished on a similar schedule in one. Shock intensity was individually adjusted to produce high or low degrees of response suppression during punishment periods in two different groups of animals. For some rats in each group, punishment periods were signalled by a flashing light; for others, by a steady light. d,l-Propranolol (2.5-7.5 mg/kg), l-propranolol (3.75, 7.5 mg/kg) and atenolol (20 mg/kg) released responding in animals in which suppression was low. These effects were restricted to the group for which the punishment signal was flashing light. The results are consistent with the view that activation of peripheral beta-adrenoceptors is involved in the suppression of responding by signals of punishment, but only in some conditions. Adding chlordiazepoxide (3.75 mg/kg) to d,l-propranolol (7.5 mg/kg) increased punished responding in the high-suppression group, but reduced it in the low-suppression group.

Adrenergic beta-Antagonists↗
PubMed1991

No effect of famotidine on cardiac performance by noninvasive hemodynamic measurements.

In a randomized, double-blind, placebo-controlled, two-way crossover study, 12 healthy volunteers were treated once daily for 1 week each with 40 mg famotidine or placebo. Stroke index, cardiac index, preejection period, left ventricular ejection time, and carotid and femoral blood flow were measured noninvasively with Doppler ultrasonography. No significant changes in these hemodynamic parameters were observed when differences between baseline and each time point after administration of famotidine were compared with corresponding differences after placebo. The findings of this study are in accord with those of other studies that have failed to demonstrate a negative inotropic effect after administration of H2-antagonists.

Adolescent↗
PubMed1991

Chronic liver dysfunction in heart transplant recipients, with special reference to viral B, C, and non-A, non-B, non-C hepatitis. A retrospective study in 80 patients with follow-up of 60 months.

In order to assess the prevalence, causes, and severity of chronic liver dysfunction (LD) in heart transplant patients, 80 transplanted patients followed for 60 months (median; range, 1.5-98 months) were reviewed. Sustained liver dysfunction was found in 50 patients, occurring during the first year after heart transplantation in 42 (84%) of them. Most patients were asymptomatic (80%). Causes for the liver dysfunction included non-A, non-B hepatitis in 16 cases (32%), viral B hepatitis in 13 (26%), delta hepatitis in one (2%), drug-induced hepatitis in six (12%), and cardiac failure in seven (14%). Anti-HCV antibodies were found in 56.2% of patients with non-A, non-B hepatitis and in 22% of patients with HBV hepatitis. It was found neither in patients with drug-induced hepatitis cardiac failure nor in patients with normal liver tests. This study outlines a high prevalence of LD (62.5%) in heart transplant patients, the high frequency of viral-related chronic LD (usually of moderate severity), and high incidence of HCV and HBV hepatitis.

Adolescent↗
PubMed1990

Effects of temporary withdrawal from regular running.

Forty regular male runners were divided into two similar groups and studied for six weeks. One group continued normal running, but the other stopped running for the middle two weeks of the study. Questionnaires were completed at the end of each week. Symptoms of depression were greater in the withdrawn than in the control group at the end of the second week of withdrawal. Somatic symptoms, anxiety, insomnia and feelings of being under strain were greater in the withdrawn group after both the first and second weeks of withdrawal. The groups did not differ in the final two weeks, when running had been resumed. These effects strengthen the view that stopping regular physical exercise produces a 'withdrawal syndrome', and that exercise might therefore be regarded as addictive. The increase in depression may reflect a more gradual loss of the antidepressive effect of exercise training.

Adaptation, Psychological↗
PubMed1990

Effects of propranolol on, and noradrenergic correlates of, the response to nonreward.

Rats were rewarded by food for running in a straight runway with short (15 sec) intertrial intervals. On the final day, animals were subjected to either 14 extinction trials or 14 rewarded trials. During acquisition, half of each group had been injected once daily for 15 days with propranolol (5 mg/kg IP), the remainder with saline vehicle. All animals were killed immediately after the final trial and the cerebral cortex taken for noradrenaline assay and radioligand binding to beta- and alpha 2-adrenoceptors. Propranolol increased running times early in extinction; this effect was replicated in a second experiment. Neither the drug injections nor the extinction procedure affected neurochemical measures. However, the rate of extinction correlated positively with both beta- and alpha 2-adrenoceptor number. Although consistent with the theory that beta-adrenoceptors are involved in adaptation to stress, these results differ from our previous findings. The relationship between beta-adrenoceptor number and the response to stress may depend on the severity of the stress.

Animals↗
PubMed1990

Acute and chronic effects of propranolol on extinction of rewarded running in the rat.

Three experiments examined the effect of propranolol injected IP on a series of 16 extinction trials at 24-hour intertrial intervals after continuously rewarded running. In Experiment I, propranolol (1, 5 or 10 mg/kg) was injected, in different groups, shortly before or shortly after each extinction trial, but without effect. In Experiment II, the same doses were injected daily for 18 days preceding extinction, to allow longer for any long-term drug effect to accumulate. Propranolol (1 mg/kg) facilitated extinction. In Experiment III, a single dose (7.5 mg/kg) was injected before or after extinction trials as in Experiment I; the acute effect was to impair extinction. These results are consistent with previous findings in the Skinner box that propranolol has an acute disinhibitory effect on nonrewarded responses and a long-term inhibitory one. These effects have different dose-response relationships.

Animals↗
PubMed1990

Endogenous opioids modulate the cardiovascular response to mental stress.

The role of endogenous opioids in the cardiovascular response to mental stress was investigated in two controlled studies. In the first, cardiovascular, hormonal and psychological measures were made in a group of subjects before, during and after presentation of either a mental stress task or a non-stressful control task in the presence of naloxone (8 mg), an opiate antagonist, or an equal volume of saline. The study was carried out in random order and single(subject)-blind. Naloxone specifically enhanced the heart rate response to the stressful task but had no effect on blood pressure, plasma epinephrine or norepinephrine, or feelings of anxiety. Naloxone increased plasma cortisol and ACTH in both stressful and control tasks. A second, double-blind, study replicated the effect on heart rate. An endogenous opioid mechanism thus appears to inhibit the cardiovascular response to stress.

Adolescent↗
PubMed1990

Relationships between happiness, behavioural status and dependency on others in elderly patients.

Feelings of dependency on others were measured, by different scales, in two different samples of elderly people: 33 acute in-patients and 25 attenders at a geriatric day hospital. Findings were similar in each location. Dependent attitudes increased with the duration of patients' previous in-patient experience, and correlated negatively with subjective well-being but not at all with behavioural status. These results are consistent with theories which attribute low morale to feelings of dependence and this, in turn, to the experience of residential care. They are inconsistent with the view that dependence on others is a positive feature of old age. In addition, patients' subjective well-being was completely unrelated to nurse ratings of their behavioural status, and subjective ratings by nurses correlated somewhat with patients' behavioural status but not at all with their subjective well-being.

Aged↗
PubMed1990

Women's anticipation and experience of childbirth: the independence of fulfillment, unpleasantness and pain.

Adjectives or phrases used by women in their description of childbirth were identified by interviewing two groups of 10 women, one drawn from an antenatal clinic, the other following delivery of a healthy child. The terms obtained were formed into a questionnaire on which 106 antenatal women described their expectations of childbirth and 82 postnatal women described their experience. Principal components analysis revealed two important findings. First, the ratings were multidimensional; that is, a dimension of fulfillment and achievement was independent of one of emotional feeling. Second, painfulness was not associated with either dimension.

Adaptation, Psychological↗