PubMed Health⌕ Search

Biomedical subjects

G van den Berg

Publications and source records attributed to G van den Berg.

28 records · Page 2Linked to original sources
PubMed1991

The effects of incorrect pain expectations on acquired fear and pain responses.

Previous experimental research on the effects of incorrect intensity expectations of aversive events can be criticized because intensity expectations were not manipulated independently from changes in objective intensity. The present study aims at investigating the effects of incorrect intensity expectations on the immediate and later responses to a painful stimulus, and on the acquisition of anticipatory responses, with proper experimental control. Subjects (n = 62) received 20 painful stimuli of varying intensity. In the control group intensities were correctly signalled on all trials by an analogue signal. On 3 trials the signal was too large in the overprediction condition, and too small in the underestimation condition. Underpredicted painful experiences were related to subsequent higher pain responses on the physiological level, but not on the subjective level; and to increased anticipatory responses (increased pain expectations, uncertainty, subjective fear, skin conductance responses). Skin conductance level also indicated increased fear after underpredicted experiences. Overpredicted painful experiences were related to a faster decrease in subjective fear compared to the control group, but did not influence other variables. The findings support the notion that underpredictions contribute to the acquisition of fear and disrupt habituation processes. The asymmetrical processing of the two kinds of incorrectly predicted experiences is discussed.

Adult↗
PubMed1991

A retrospective study on seven years of multiple drug treatment for paucibacillary and multibacillary leprosy, in Bayara General Hospital, Nigeria.

In Bauchi State, Nigeria, a retrospective study was carried out among 973 patients on multidrug therapy (MDT), multibacillary (MB) and paucibacillary (PB), and 118 patients on a dapsone-clofazimine therapy. These patients were registered between January 1983 and September 1989. Clinical results and the problem of defaulting were investigated. The most important conclusions drawn are: although relapses occur, MDT-PB can be a valuable treatment; health education, shorter duration of treatment and permission to come less often lower the default rate, but in spite of this, the distance between home and clinic remains a problem.

Adolescent↗
PubMed1986

Inhibitory effect of alpha-1 adrenoceptor stimulation on cardiac sympathetic neurotransmission in pithed normotensive rats.

In the present study we investigated the inhibitory effect of the selective alpha-1 adrenoceptor agonists cirazoline, amidephrine and St 587 on the cardiac sympathetic neurotransmission in pithed normotensive rats. Increases in heart rate were elicited by electrical stimulation of the cardiac sympathetic nerves or by i.v. administration of norepinephrine, isoproterenol or tyramine. Intravenous pretreatment of the animals with cirazoline, amidephrine or St 587 diminished the heart rate response to sympathetic stimulation significantly. However, the tachycardia produced by norepinephrine, isoproterenol or tyramine was also inhibited significantly by the selective alpha-1 adrenoceptor agonists. The selective alpha-1 antagonist prazosin blocked the sympathoinhibitory effect to alpha-1 adrenoceptor stimulation significantly. However, the inhibitory effect of cirazoline and St 587 was not suppressed completely by a maximally effective dose of prazosin. In contrast, the sympathoinhibitory action of amidephrine was antagonized completely by prazosin. However, the selective alpha-2 antagonist rauwolscine also produced a significant, albeit modest, attenuation of the sympathoinhibitory effect to amidephrine. The results of the present study indicate that alpha-1 adrenoceptor agonists, at relatively high doses, inhibit the sympathetic neurotransmission in rat heart. This sympathoinhibitory effect is mediated largely by alpha-1 adrenoceptors which are localized postjunctionally rather than prejunctionally.

Adrenergic alpha-Agonists↗