Biomedical subjects

P Bjerring

Publications and source records attributed to P Bjerring.

At least 55 records · Page 3Linked to original sources

PubMed1995

Analgesic effect in humans of subanaesthetic isoflurane concentrations evaluated by experimentally induced pain.

The analgesic effect of subanaesthetic concentrations of ether, trichloroethylene, methoxyflurane and halothane has been investigated previously using either clinical assessment or pain threshold measurements, but with conflicting results. The purpose of the present study was to evaluate the analgesic effect of isoflurane using experimental pain models. We studied 12 healthy volunteers at three randomly chosen subanaesthetic isoflurane concentrations: low (0.10-0.14 vol%), middle (0.16-0.20 vol%) and high (0.22-0.26 vol%). We used thermal pain detection and pain tolerance thresholds to argon laser stimulation, pressure pain detection and pain tolerance thresholds, immersion of the hand in ice water, and the nociceptive reflex to single and repeated (temporal summation) electrical stimulations, as experimental models to assess analgesia. There were no significant changes in the response to heat, cold or mechanical pressure at any of the subanaesthetic concentrations of isoflurane used. The nociceptive reflex thresholds to single stimulations, but not the thresholds for repeated stimulations, were significantly increased in all three isoflurane groups compared with baseline values. The difference between the different isoflurane concentrations was not statistically significant. In experimental pain models, subanaesthetic isoflurane concentrations have little or no analgesic potency.

Adult↗

PubMed1995

The effect of N-methyl-D-aspartate antagonist (ketamine) on single and repeated nociceptive stimuli: a placebo-controlled experimental human study.

Ketamine is a noncompetitive N-methyl-D-aspartate (NMDA) receptor channel blocker known to inhibit "wind-up" and hence central hyperexcitability of dorsal horn neurons. We sought to assess the effect of ketamine on single and repeated nociceptive stimuli. A placebo-controlled, human (12 volunteers) experimental study was conducted in which several psychophysical (pain detection and tolerance thresholds, magnitude ratings) and electrophysiologic (withdrawal reflex) techniques were used 1) to investigate whether a ketamine (0.5 mg/kg) bolus followed by a 20-min infusion (9 micrograms.kg-1.min-1) inhibits central temporal summation to repeated nociceptive electrical stimuli, and 2) to assess quantitatively the hypoalgesic potency using several experimental nociceptive stimuli (argon laser, pressure, electrical). Facilitation of the withdrawal reflex to and pain rating of repeated electrical stimuli (five pulses at 2 Hz) were inhibited by ketamine. Reflex and pain rating to a single stimulus did not change. The pressure pain detection and tolerance thresholds were increased significantly by ketamine, whereas the laser heat pain and tolerance thresholds remained stable compared with placebo. The stimulus response function showed that ketamine reduced the responses to the highest electrical stimulus intensities (1.4, 1.6, and 1.8 times the reflex threshold). We conclude that ketamine inhibits central temporal summation in humans and has a marked hypoalgesic effect on high intensity nociceptive stimuli.

Analgesics↗

PubMed1995

Photopheresis in the red man or pre-Sézary syndrome.

BACKGROUND: The beneficial effect of extracorporeal photochemotherapy has clearly been established for patients with cutaneous T-cell lymphoma with Sézary's syndrome. But this treatment has not been used in the red man syndrome or pre-Sézary syndrome. Some of these patients do not respond sufficiently or do not tolerate other therapies. OBJECTIVE: The purpose of this open study was to evaluate the clinical efficacy of photopheresis in this group of patients. METHODS: Seven patients with the red man syndrome were treated on 2 consecutive days every 4 weeks for 6-22 months. Six had been on systemic steroids and 3 had also received retinoids without sufficient effects. All were initially treated with topical nitrogen mustard but no longer tolerated this treatment. RESULTS: All signs of erythroderma disappeared in 6 of the 7 patients. All systemic therapy could be discontinued in all but 2 patients. No side effects were observed. CONCLUSION: Photopheresis may be an effective alternative treatment for this group of patients, when other types of therapy have failed.

Acitretin↗

PubMed1995

Glucose content in human skin: relationship with blood glucose levels.

In order to ascertain the dynamic relationship between the extracellular glucose in upper skin layers and blood glucose, skin suction blisters were raised in six Type 1 diabetic patients during a three-step glucose clamp. Blister glucose closely paralleled venous glucose (mean of r = 0.998). However, in three patients blister glucose was constantly lower than plasma glucose and this appeared to be related to their slower formation of skin blisters. A substantial difference in skin blister suction time was noted among patients and it was found that suction time was linearly correlated to glycosylated haemoglobin (HbA1C) (n = 6, r = 0.865, p = 0.026). It is concluded that a non-invasive blood glucose monitoring system could be successfully based on measurement of alterations in skin glucose contents.

Adolescent↗

PubMed1994

Laser-induced pain-related brain potentials and sensory pain ratings in high and low hypnotizable subjects during hypnotic suggestions of relaxation, dissociated imagery, focused analgesia, and placebo.

Pain reports and amplitudes of painful argon laser-induced brain potentials were obtained for 10 high and 10 low hypnotizable volunteers following placebo and a randomized sequence of four hypnotically induced conditions of (a) neutral hypnosis, (b) deep relaxation, (c) pleasant dissociated "out of body" imagery, and (d) focused analgesia of the hand. Both high and low hypnotizable subjects exhibited significant reductions of reported pain during conditions of neutral hypnosis, relaxation, dissociated imagery, and focused analgesia. High hypnotizable subjects displayed significantly greater reductions than low hypnotizables in all conditions except placebo. Both high and low hypnotizables exhibited significant reductions of reported pain in all five conditions as well as in the posthypnotic condition, when amplitudes of evoked potentials were compared to the prehypnotic baseline. Only the high hypnotizable group showed significant reductions in amplitudes when the data were recalculated to reflect relative changes compared to the average amplitude of the pre- and postconditions to compensate for a possible habituation effect indicated by the significantly lowered amplitudes in the posthypnotic condition. The results are discussed in light of a number of hypotheses concerning mechanisms of hypnotic analgesia.

Adult↗

PubMed1994

Ondansetron does not inhibit the analgesic effect of alfentanil.

5-Hydroxytryptamine (5-HT) causes antinociception via presynaptic 5-HT3 (5-HT subtype 3) receptors on primary afferent nociceptive neurones in the spinal cord dorsal horn. Therefore, ondansetron (a 5-HT3 receptor antagonist) may increase the perception of a noxious stimulus or decrease the effects of concurrently administered antinociceptive drugs. Using a randomized, double-blind, crossover study design, we have tested this hypothesis in eight healthy volunteers who, on three different days, received either ondansetron and placebo, ondansetron and alfentanil or placebo and alfentanil. Experimental pain was induced with heat, cold, mechanical pressure and electrical stimulation. Ondansetron alone did not change the response to any of the experimental tests, but alfentanil and the combination ondansetron-alfentanil significantly changed the response compared with ondansetron alone. There was no difference between alfentanil alone and the combination ondansetron-alfentanil. We conclude that ondansetron does not change the response to pressure, heat, cold or electrical nociceptive stimuli or antagonize the analgesic effect of alfentanil.

Adult↗

PubMed1994

Morphine does not affect laser induced warmth and pin prick pain thresholds.

The aim of this double-blind, placebo-controlled study was to evaluate the effect of intravenously administered morphine in humans using an argon laser to induce experimental pain. Thirty volunteers were randomised to receive a total of 0.15 mg.kg-1 morphine intravenously or saline. The argon laser was used to determine the possible change in warmth thresholds and pin prick pain thresholds. Measurements were performed before and at 10, 20, 30 and 40 min after the injection. During the observation period the warmth thresholds increased 20.7% (P < or = 0.05) from baseline (0.82 W +/- 0.42 W) in the morphine group while an increase of 14.3% (P > or = 0.05) was seen in the placebo group (Baseline: 0.91 +/- 0.37). The pinprick pain thresholds of the morphine group increased 9.4% (P < or = 0.05) from baseline (1.39 W +/- 0.7 W) while the corresponding thresholds of the placebo group was 4.6% (P > or = 0.05) (baseline: 1.73 W +/- 0.44 W). The differences seen between the morphine group and the placebo group were not statistically significant and thus it was demonstrated that morphine had no effect of either the feeling of warmth or the pain elicited by the argon laser. The present study supports other investigations and clinical experience suggesting that intermittent pain is not relieved by morphine unlike continuous pain, which can be relieved by morphine.

Adult↗

PubMed1994

Plasma endothelin and the aminoterminal propeptide of type III procollagen (PIIINP) in systemic sclerosis.

Forty-four patients with systemic sclerosis and 3 patients with localized scleroderma were investigated for plasma endothelin and aminoterminal propeptide of type III procollagen (PIIINP). Although there was an overlap between plasma levels of endothelin in patients with systemic sclerosis and healthy controls, the mean value of the patients was significantly higher than in controls. Plasma endothelin was normal in all 3 patients with localized scleroderma. The highest levels of plasma endothelin were found in patients with type II and III systemic sclerosis with the largest cutaneous involvement, and in patients with the scleroderma-specific antibodies Scl-70 and anticentromere antibodies. Extremely high values were found in a patient who experienced a renal crisis and in a patient who had her lower leg amputated due to severe vasculitis. A positive correlation was found between plasma endothelin and serum PIIINP. This, together with the fact that in systemic sclerosis the vascular lesions are the earliest, would seem to support the theory that endothelial cell damage could lead to increased secretion of endothelin and subsequent fibrosis in this disease.

Aged↗

PubMed1994

Skin scoring in systemic sclerosis: a modification--relations to subtypes and the aminoterminal propeptide of type III procollagen (PIIINP).

Forty-one patients with systemic sclerosis were investigated with a new and simple skin score method measuring the degree of thickening and pliability in seven regions together with area involvement in each region. The highest values were, as expected, found in diffuse cutaneous systemic sclerosis (type III SS) and the lowest in limited cutaneous systemic sclerosis (type I SS) with no lesions extending above wrists and ancles. A positive correlation was found to the aminoterminal propeptide of type III procollagen, a serological marker for synthesis of type III collagen. The skin score is considered simpler than previous methods and is recommended for more general use.

Arm↗

PubMed1994

Onset and duration of hypoalgesia following application of lidocaine spray on genital mucosa.

Lidocaine spray is used as a topical analgesic prior to minor surgical procedures performed on genital mucosa. In this study onset and duration of hypoalgesia on the genital mucosa was investigated by spraying lidocaine solution on the mucous membranes of female genitals with subsequent measurements of pin prick pain thresholds induced by argon laser stimulation. A dosage of 50 mg of lidocaine spray was administered to the genital mucosa of the inside of the labiae minora. Repeated measurements of pain threshold were performed until normal sensitivity was reached. Analgesia to 1.5 W laser stimulation was obtained in all volunteers after an average of 2.7 min +/- 1.3 min (s.d.) (Range: 1-4 min). The effect lasted 29.7 min +/- 8.9 min (s.d.) (Range 12-45 min). The application of lidocaine spray produced a painful, smarting sensation which, however, disappeared again after 15-30 seconds. The study suggests that minor surgery should not be performed earlier than 4 min after application of lidocaine spray and it is recommended that it should be remembered that the duration of analgesia varies between individuals and thus may be very short in some patients.

Administration, Topical↗

PubMed1994

Effects of hypnotic suggestions on ultraviolet B radiation-induced erythema and skin blood flow.

Results from both animal and human studies have indicated that inflammatory skin reactions such as the flare response to histamine prick test involve a neurogenic regulatory component. It is still unknown to which degree inflammation induced by ultraviolet (UV) radiation may be mediated by the central nervous system. To investigate this, the effect of hypnotic suggestions to increase and decrease the response to UVB radiation on erythema and cutaneous blood flow was investigated in 10 highly hypnotizable subjects. The results showed a significant effect of hypnotic suggestions on cutaneous blood flow compared with the responses of a control group. For erythema no conclusive evidence was found. The results indicate the possibility of separate regulatory mechanisms behind central nervous system influence on UVB-induced erythema and skin blood flow respectively, and further investigations are needed.

Adult↗

PubMed1993

Sensory and pain thresholds to orofacial argon laser stimulation in patients with chronic burning mouth syndrome.

OBJECTIVE: Psychophysical assessments of orofacial sensory function were performed in order to investigate neurophysiological aspects of the burning mouth syndrome (BMS). DESIGN: Sensory and pain thresholds to brief argon laser stimulation were determined on six test regions, which included the tip of tongue, the lower lip mucosa and skin, the buccal mucosa, the anterior hard palate, and the dorsum of the hand. SETTING: The experimental examination was performed at the Pain Clinic Unit at the Royal Dental College. PATIENTS: Twenty-three elderly denture-wearing patients diagnosed as suffering from BMS were studied, and a control group included 23 age-, sex-, and denture-matched subjects. The obtained thresholds were compared between groups. RESULTS: Sensory thresholds were significantly higher and ratios between pain and sensory thresholds significantly lower in patients with BMS on all the tested regions. Pain thresholds were significantly elevated on the lower lip skin, the anterior hard palate, and the hand in patients with BMS. At sensory threshold level, a faint pinprick perception was often reported by patients with BMS contrary to a perception of warmth described by control subjects. The intraregional variations in sensory and pain thresholds on the hard palate, the lower lip mucosa, and on the skin were similar in both groups, but differences occurred in sensory thresholds on the tongue in patients with BMS. CONCLUSIONS: The presence of abnormal prepain perceptions and disturbances in the perception of nonnociceptive and nociceptive thermal stimuli applied on both pain-affected and normal regions suggest a perceptual deficit unrelated to specific pathophysiological mechanisms in BMS. However, it appears that a psychological explanation of BMS should be used cautiously, as the present results suggest alterations in sensory function.

Aged↗

PubMed1993

Increase and decrease of delayed cutaneous reactions obtained by hypnotic suggestions during sensitization. Studies on dinitrochlorobenzene and diphenylcyclopropenone.

Cutaneous reactivity to challenge with dinitrochlorobenzene (DNCB) and diphenylcyclopropenone (DCP) was studied in 16 volunteers following hypnotic suggestions to increase and decrease response during sensitization. The immunoreactivity to DNCB and DCP was modulated by direct suggestions and guided imagery under hypnosis. The volunteers were highly susceptible subjects selected by means of the Harvard Group Scale of Hypnotic Susceptibility, Form A. Measurement of skin reactions to the challenge 1 month after sensitization was performed double blindly. Results showed a significant (P < 0.01) difference in visually scored reactions to DCP and DNCB between the group instructed to increase reaction to DCP and decrease reaction to DNCB and the group given the opposite instructions. A non-significant difference (P = 0.055) in skin thickness measured by ultrasound was found between the two groups. The study supports previous reports of experimental modulation of immunoreactivity and indicates that the specific immunological processes involved in the development of allergic reactions may be susceptible to psychological factors.

Adult↗

PubMed1993

Comparison of the bioactivity of mometasone furoate 0.1% fatty cream, betamethasone dipropionate 0.05% cream and betamethasone valerate 0.1% cream in humans. Inhibition of UV-B-induced inflammation monitored by laser Doppler blood flowmetry.

The bioactivity of a novel topical glucocorticosteroid, mometasone furoate 0.1% fatty cream was compared with betamethasone dipropionate 0.05% cream and betametasone valerate 0.1% cream. An ultraviolet light (UV-B)-induced inflammation assay in humans was used, and the combined effect of a single, open application of the corticosteroids was evaluated. Reduction of UV-B induced inflammation was monitored by laser Doppler blood flowmetry, clinical skin scoring and skin reflectance spectrophotometry. Skin scoring and reflectance spectrophotometry were found unsuitable because one of the cream vehicles contained titanium dioxide which shielded skin erythema. Laser Doppler blood flowmetry showed that mometasone furoate 0.1% fatty cream was more than twofold better in reducing UV-B-induced inflammation than betamethasone dipropionate 0.05% cream and betametasone valerate 0.1% cream, and that the effect was sustained for at least 24 h after a single application.

Administration, Topical↗

PubMed1993

Photopheresis in systemic sclerosis: clinical and serological studies using markers of collagen metabolism.

Eight patients with progressive systemic sclerosis were treated with photopheresis or extracorporeal photochemotherapy given on 2 consecutive days every 4 weeks for 5 to 8 months. Previous treatment with immunosuppressive agents or D-penicillamine was discontinued for at least 4 weeks prior to photopheresis. Although IL-2 receptor density in peripheral blood T-lymphocytes decreased significantly in the initial phase of the photopheresis therapy, no substantial clinical improvement occurred. Although the intention had been to treat all patients for at least 8 months with photopheresis alone, it was mandatory due to severe exacerbations to give additional immunotherapy to 4 patients, and 2 of these together with another patient wanted to discontinue photopheresis after 5 and 6 months, as they did not expect an effect. Three of the 4 patients with progression had RNP-antibodies, suggesting that they had their scleroderma as part of a mixed connective tissue disease. The clinical exacerbations were accompanied in all patients by a highly significant increase in serum aminoterminal propeptide of type III procollagen (PIIINP), which has been reported to correlate with involvement of skin and internal organs in systemic sclerosis. Similar but less significant increases were found in serum carboxyterminal propeptide of type I procollagen (PICP); there were no significant changes in serum cross-linked fragment of type I collagen. Plasma levels of 8-methoxypsoralen were all above 80 ng/l, showing that the lack of responses to photopheresis could not be due to poor absorption of the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Duration of analgesia following application of eutectic mixture of local anaesthetics (EMLA) on genital mucosa.

The topical anaesthetic formulation EMLA cream (eutectic mixture of local anaesthetics) is increasingly used prior to minor painful procedures performed on genital mucosa. The aim of the present study was to gain knowledge about the correlation between duration of application of EMLA and duration of analgesia. Three different application times--5, 10 and 20 min--were investigated in 12 healthy young women. Pin-prick pain thresholds to argon laser stimulation were measured before and after application of EMLA. Repeated measurements were performed until normal sensitivity returned. No significant difference in duration of analgesia was seen between the three application times. However, 10 min application time tended to produce the longest mean duration of analgesia (22.2 min). Surprisingly, a large inter-individual variation in duration of analgesia was seen. Thus, after 10 min application time the shortest duration of sufficient analgesia was 5 min, while the longest was 46 min. On the basis of this work, it seems advisable to start minor surgery on genital mucosa after about 10 min application time, and it is recommended to bear in mind that the duration of analgesia varies and may be very short in some patients.

Adult↗

PubMed1993

Oral mucosal analgesia quantitatively assessed by argon laser-induced thresholds and single-evoked vertex potentials.

The aim of this study is to quantitate the efficacy of a new topical anesthetic applied to the oral mucosa. Nociceptive pinprick thresholds and single-evoked vertex potentials (VP) elicited by high-intensity argon laser stimuli are used as measures of analgesia. After 5 minutes of occlusion (Orahesive Oral Bandages, ConvaTec) with a eutectic mixture of local anesthetics (EMLA cream, Astra), nociceptive pinprick thresholds on the tongue and gingiva are higher than those taken during nonocclusion. In a double blind-placebo controlled experiment, VPs were elicited every 1 minute for 19 minutes by single laser stimuli applied to the mucosa of the lower lip. After occlusion with EMLA cream for 3 minutes, VPs were significantly reduced when compared to those with placebo cream. One minute after removal of the EMLA cream, the spectral power of the single-evoked VP decreased significantly by 63.3%, the root-mean-square amplitude decreased by 42.7%, and the subjective pain perception (estimated on visual analogue scales) decreased by 88%. A significant reduction in single-evoked VPs was detected until 13 minutes after the removal of the EMLA cream. Oral mucosal analgesia may be quantitated by argon laser-induced nociceptive pinprick thresholds and single-evoked VPs.

Adult↗

PubMed1993

Vertex potentials evoked by nociceptive laser stimulation of oral mucosa: relationship to stimulus intensity.

The present study investigated the relationship between stimulus intensity and size of vertex potentials (VPs) and methods for quantification of VPs elicited by nociceptive argon laser stimulation of the oral mucosa. VPs were evoked by warning and self-triggered stimulation of the tongue and hand. A significant increase was found in amplitude, power, and root-mean-square (RMS) values of the averaged VPs as the intensity of the laser stimuli increased. The latency of the major negative peak decreased significantly with increased stimulus intensity. The use of a warning light stimulus prior to the laser stimulus elicited a visually evoked vertex potential, which served as a control. The power and RMS values of the VPs elicited by warning stimulation of the tongue showed the largest increase and only a small variation when calculated in the 0.2 to 0.7 seconds time interval.

Adult↗