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Biomedical subjects

B Etholm

Publications and source records attributed to B Etholm.

15 recordsLinked to original sources
PubMed1990

A multicentre study of loratadine, clemastine and placebo in patients with perennial allergic rhinitis.

This multicentre, double-blind, randomized parallel-group study compared 3 weeks' treatment with either loratadine (Clarityn) 10 mg once daily, or clemastine (Tavegyl) 1 mg twice daily, and placebo in outpatients with active perennial allergic rhinitis. 155 patients were evaluated for efficacy and safety. Grading of four nasal and three non-nasal symptoms, rhinoscopy signs, and therapeutic response was performed on treatment days 6, 13, and 20. Patients recorded daily symptoms and possible adverse experiences in a diary, also indicating when symptoms of active rhinitis were relieved. Loratadine and clemastine were statistically significantly superior to placebo throughout the study (P less than 0.05), based on assessment of patients' nasal and eye symptoms, patients' diary scores, rhinoscopy signs of symptoms, and onset of relief. The loratadine group showed a statistically significantly (P less than 0.05) faster onset of relief of symptoms compared with the group treated with clemastine. Concerning nasal stuffiness, loratadine was significantly (P less than 0.05) superior to clemastine after 1 week's treatment. Reports of adverse reactions showed that significantly (P less than 0.05) more patients complained of sedation in the clemastine than in the loratadine group. Regarding other adverse experiences and laboratory tests, the three treatment groups were statistically comparable (P less than 0.05). The study showed that compared with placebo both loratadine and clemastine were effective in relieving nasal and eye symptoms in patients with perennial allergic rhinitis. Loratadine was safe and well tolerated and was significantly less sedative than clemastine; loratadine may therefore possess an advantage in clinical use in the treatment of perennial allergic rhinitis.

Adolescent↗
PubMed1970

Presynaptic and post-synaptic inhibition elicited in the cat's dorsal column nuclei by mechanical stimulation of skin.

1. Primary afferent depolarization (PAD), with a time course comparable with that of the PAD following limb nerve stimulation, was produced in the cuneate nucleus by mechanical stimulation of the skin of the ipsilateral forepaw. Brushing or blowing on hairs was as effective as any other form of stimulation and there was a rapid adaptation to a sustained stimulus. Up to 55% increase in excitability was produced by blowing on hairs.2. The P-wave and the PAD produced by mechanical stimulation were at a minimum in the rostral part of the cuneate nucleus and at a maximum 2-6 mm caudal to the obex.3. The distribution of the PAD produced in the gracile nucleus by blowing on the skin of the hind foot was studied by a technique allowing measurement of excitability changes near the terminals of single fibres. Minimal values were obtained rostral to the obex and maximal values 1-4 mm caudal to the obex, a distribution matching that previously determined for single cells subject to surround inhibition.4. Post-synaptic inhibition was produced in the cuneate nucleus by gentle blowing on the ipsilateral forepaw. Up to 20% fall in excitability occurred in populations of cells tested by direct electrical stimulation. IPSPs lasting up to 160 msec were observed in single cells following light mechanical stimulation in the immediate neighbourhood of these cells' receptive fields. Blocking of antidromic invasion of single cells was occasionally produced by mechanical skin stimulation.5. It is concluded that both pre- and post-synaptic inhibition must be concerned in the phenomenon of afferent surround inhibition, though there was no evidence to indicate their relative roles, qualitatively or quantitatively.6. It is shown that up to 20% reduction in transmission through the gracile or cuneate nucleus could be produced by blowing on the ipsilateral hind paw or forepaw respectively, measured as reduction in the area of the monophasically recorded lemniscal response. A single electrical stimulus to the skin of the contralateral forepaw reduced transmission through the cuneate nucleus by less than 5%.

Action Potentials↗
PubMedDate not supplied

Inhibitory processes in the medial geniculate body.

Inhibition in the medial geniculate body was studied with a double click technique. A conditioning click caused a marked inhibition of field potentials and unit discharges to a subsequent test click. Cyclic inhibition with a period of about 150 ms was seen in the medial geniculate body and the auditory cortex, but not in the inferior colliculus. The postsynaptic excitability was tested by recording from the killed ends of the thalamocortical fibres. A preceding click reduced the direct response to a test stimulus delivered to the medial geniculate body indicating the presence of postsynaptic inhibition. The excitability of the fibres from the inferior colliculus terminating in the medial geniculate body was tested with a modified Wall (1958) method. The results suggest the presence of a presynaptic inhibitory mechanism in the medial geniculate body. The techniques employed do not allow an estimation of the relative contribution of the two inhibitory mechanisms to the inhibition at the medial geniculate level.

Acoustic Stimulation↗
PubMedDate not supplied

Activity of single medial geniculate units in response to single and double clicks.

The discharge pattern to clicks and the time course and pattern of the click-induced inhibition in the medial geniculate body have been studied by single unit recording technique. The medial geniculate neurones showed a tendency to fire at preferred latencies after a click. A conditioning click caused a reduced number and increased latency of the discharges to a subsequent test click. Provided conditioning click of a certain strength was employed, the inhibition was often cyclic, each period lasting for about 100-150 ms. Clicks could also trigger barbiturate spindles with synchrony between the activity of the medial geniculate body and the primary auditory cortex. Interaction experiments suggest that the triggered and spontaneous spindle activity operate with the same neurones.

Acoustic Stimulation↗
PubMedDate not supplied

Size and duration of inhibition in the medial geniculate body in unanesthetized cats.

A method which allows repeated micro-electrode recordings from subcortical structures without using any drugs is described. This method was adopted in combination with convential implantation techniques to study click-evoked potentials and inhibitory processes in the auditory system of the cat. The click-evoked potentials in MG were hardly affected by moderate doses of barbiturate and only to a minor degree in the auditory cortex. In the unanaesthetized animal the most significant contribution to the click-evoked inhibition in the auditory system was due to mechanisms in the MG. The inhibition was diminished both in size and duration as compared with the situation in anaesthetized cats. The MG cells showed a tendency to cyclic inhibition in the unanaesthetized cat, but not so regularly as following administration of sodium pentobarbital. The action of barbiturates on the auditory system is discussed.

Acoustic Stimulation↗