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Biomedical subjects

P Bjerring

Publications and source records attributed to P Bjerring.

At least 109 records · Page 6Linked to original sources
PubMed1990

A quantitative comparison of the effect of local analgesics on argon laser induced cutaneous pain and on histamine induced wheal, flare and itch.

A quantitative comparison was made of the effect of infiltration of local analgesics and topical analgesic cream (EMLA) on laser-induced pain and histamine-induced wheal, flare and itch. Wheal and flare were quantified by planimetry and analgesia was quantified by the pricking pain threshold to argon laser stimulation. The intensity of histamine-induced itch was scored on a 4-point scale. Local analgesics had no effect on the wheal area. The flare reaction was abolished by infiltrating lignocaine, and gradually inhibited by increased application times of EMLA. Itch was abolished after local lignocaine infiltration, but not significantly reduced after EMLA cream applied for less than 120 min, although the skin was anaesthetized to laser-induced pain. The reduction of flare area correlated to the level of analgesia, which may therefore reflect the cutaneous responsiveness to neurogenic inflammation. It is suggested that itch and pricking pain are mediated by different populations of nerve fibres, as itch can be evoked even when the sensation of pricking pain is abolished. Surgery, skin prick tests and other traumatic procedures should therefore be performed under local anaesthesia to reduce neurogenic inflammation.

Administration, Topical↗
PubMed1990

Regional variations in analgesic efficacy of EMLA cream. Quantitatively evaluated by argon laser stimulation.

The effect of EMLA cream (a eutectic mixture of local analgesics) applied for 30, 60, 90 and 120 min on the forehead, cheek, back, cubital fossa, and dorsum of the hand was studied. Analgesic onset, efficacy and duration were evaluated by sensory and pain thresholds to laser stimulation measured before, and 5, 60, 120, and 180 min after the cream was removed from the skin. Cutaneous blood flow was measured and found to be 4-5 times as high on the face as on the other locations. On the forehead the analgesic efficacy decreased with increased application time. For all other locations, efficacy increased with increasing application time. On the back, onset was rapid and sufficient analgesia could be obtained, but analgesias began to wane immediately after removal of the cream. In the cubital fossa and on the hand, onset was tardy, and efficacy continued to increase for 60 min after cream removal, followed by a slow decline. Blood flow, epidermal and dermal thickness are important factors affecting onset, efficacy and duration of EMLA analgesia.

Adult↗
PubMed1990

Noninvasive computerized analysis of skin chromophores in vivo by reflectance spectroscopy.

Reflectance spectroscopy in an objective and accurate method for determining skin colour and has been widely used for measuring physiological variations in skin colour and for monitoring dermatological treatment modalities. Previous studies have used pigment indexes to describe changes in skin colour. Using a multiple regression method to calculate reflectance spectroscopic data, it has been possible to calculate the relative amounts of the different chromophores present in the skin. The technique was found reliable in in vitro tests and in experimentally induced variations in pigment content caused by venous congestion or ultraviolet (UV) light irradiation. In developing UV-induced erythema, the primary events seem to be venous dilatation followed by an increase in blood flow.

Adult↗
PubMed1990

Spectral reflectance of human skin in vivo.

A newly developed skin reflectance spectrophotometer was evaluated for measurements of both melanin pigmentation and erythema. Physiological changes in blood flow and blood content in normal humans were induced by compression with an arm cuff during recording of skin reflectance spectra. Reflectance spectra of UV-induced erythema were also recorded and compared with laser-Doppler flow measurements. Spectral reflectance measurements were found to be highly sensitive in determining minimal erythema, which was not clinically detectable. The measurements of erythema using reflectance spectroscopy and UV irradiation were very highly correlated (r = 0.996). It was possible to calculate the in vivo absorbance of oxygenized haemoglobin. The melanin pigmentation following UV irradiation was quantified by reflectance spectroscopy and correlates highly with the dose of UV irradiation (r = 0.995). Furthermore, regional variations in skin melanin and haemoglobin were analysed for fair Caucasian skin.

Adult↗
PubMed1990

House dust mites and atopic dermatitis. A case-control study on the significance of house dust mites as etiologic allergens in atopic dermatitis.

The occurrence of house dust mites was measured in homes of 24 patients with atopic dermatitis, 30 patients with mite-sensitive asthma and 32 patients with asthma not related to house dust mites. Patients with mite-positive asthma and patients with atopic dermatitis had significantly higher exposure to house dust mites compared with patients with mite-negative asthma. For atopic dermatitis the higher exposure to house dust mites corresponded to a relative risk of 4.7 and a clear dose-response relationship was demonstrated between exposure and risk of disease in the subgroups of patients with atopic dermatitis. The present epidemiologic results support the idea that house dust mites may be an etiologic factor in a proportion of adult patients with atopic dermatitis.

Allergens↗
PubMed1989

15-hydroxyeicosatetraenoic acid (15-HETE) specifically inhibits the LTB4-induced skin response.

15-Hydroxyeicosatetraenoic acid (15-HETE), a 15-lipoxygenase product of arachidonic acid, inhibits leukotriene B4 (LTB4)-induced chemotaxis of polymorphonuclear leukocytes (PMNs) in vitro. In this study the effects of intradermal injections of LTB4 were determined in the absence or presence of 15-HETE. For comparison intradermal injections of purified human complement split product C5a were performed in the absence or presence of 15-HETE. The skin response was evaluated by measuring the diameter of the wheal, the area of the flare and by intensity of the erythema (erythema index). LTB4 and C5a were injected at the concentration of 200 ng/ml. At this concentration the maximal skin response of LTB4 and C5a were equivalent. In contrast to C5a reaction, which resolved within 1 h, LTB4-induced skin response lasted up to 18 h. In all subjects the skin response was significantly decreased when LTB4 was injected together with 300 ng of 15-HETE. The decrease of wheal, flare, and erythema index averaged 81.9%, 56.6%, 53.6%, respectively, when all parameters were obtained at the maximal skin response. In contrast, the C5a-induced skin response was not affected by addition of 15-HETE, even when the final dose of 15-HETE was increased 10 times to 3 micrograms. The LTB4-induced reaction could last up to 18 h after injection. After the addition of 300 ng of 15-HETE the skin response resolved after 1 h. The present results demonstrate that 15-HETE is a specific inhibitor of the LTB4-induced skin response and brings additional evidence in support of the ability of 15-HETE to regulate the proinflammatory effects of LTB4 in vivo.

Adult↗
PubMed1989

Vascular response of human skin after analgesia with EMLA cream.

We investigated vascular responses after cutaneous application of EMLA cream (a eutectic mixture of lignocaine and prilocaine) by skin reflectance spectroscopy and laser Doppler blood flowmetry. In healthy subjects, EMLA cream produced a biphasic vascular response with an initial vasoconstriction, maximal after 1.5 h of application. After prolonged application (greater than 3 h, vasodilatation occurred, presumably because of a smooth muscle relaxant effect of the analgesics. Vasoconstriction was also observed initially with two non-EMLA creams applied under occlusion, whereas the occlusive plastic film alone did not alter the vascular state. Thus late vasodilatation was unique to EMLA cream.

Adult↗
PubMed1989

Modulation of type I immediate and type IV delayed immunoreactivity using direct suggestion and guided imagery during hypnosis.

Cutaneous reactivity against histamine skin prick test (Type I) and purified tuberculin protein derivative (Mantoux reaction, Type IV) was studied in eight volunteers under hypnosis. Types I and IV immunoreactivity were modulated by direct suggestion (Type I) and guided imagery (Type IV). The volunteers were highly susceptible subjects, selected by means of the Harvard Group Scale of Hypnotic Susceptibility, Form A. When the volunteers underwent hypnotic suggestion to decrease the cutaneous reaction to histamine prick test, a significant (P less than 0.02) reduction of the flare reaction (area of erythema) was observed compared with control histamine skin prick tests. The wheal reaction did not respond to hypnotic suggestion. Neither wheal nor flare reaction could be increased in size by hypnotic suggestion compared with control histamine skin prick tests. A hypnotic suggestion of increasing the Type IV reaction on one arm and decreasing the reaction on the other revealed a significant difference in both erythema size (P less than 0.02) and palpable induration (P less than 0.01). In two cases the reactions were monitored by laser doppler blood flowmetry and skin thickness measurement by ultrasound. The difference between the suggested increased and decreased reaction was 19% for the laser doppler bloodflow (in favor of the augmented side), and 44% for the dermal infiltrate thickness. This study objectively supports the numerous uncontrolled case reports of modulation of immunoreactivity in allergic diseases involving both Type I and Type IV skin reactions following hypnotic suggestions.

Adult↗
PubMed1989

The effect of topically applied anaesthetics (EMLA cream) on thresholds to thermode and argon laser stimulation.

The cold and warmth thresholds to thermode stimulation and the sensory and pain thresholds to argon laser stimulation were determined before and after topical application of EMLA (Eutectic Mixture of Local Anaesthetics) cream. The sensory threshold to argon laser stimulation and warmth threshold to thermode stimulation are both described in terms of warmth or faint heat. The sensory threshold persisted for more than 80 min of EMLA application, whereas the warmth and cold thresholds were detectable after 105 min in half the volunteers. Pain evoked by strong laser pulses was abolished after 80 min of cream application. The analgetic effect of topically applied lidocaine/prilocaine, evaluated by the cutaneous thermal and pain threshold, is compatible with the idea that topical application of EMLA cream blocks free nerve endings rather than the nerve fibres, and induces a sequence of sensory loss which, in some respects, differs from that typically observed after perineural application of local anaesthetics. The effect of topically applied anaesthetics is influenced by a number of thermodynamical, anatomical, and physiological factors in the skin.

Administration, Cutaneous↗
PubMed1989

Use of a new argon laser technique to evaluate changes in sensory and pain thresholds in human skin following topical capsaicin treatment.

A new argon laser technique was introduced to evaluate the excitability of the free nerve endings in the skin following topical application of capsaicin. Short argon laser pulses can be perceived as distinct, painful pin pricks and the pain threshold can be determined. This gives the possibility to follow changes in sensory and pain thresholds after topical application of various substances. In the present study the long-term effect of topically applied capsaicin on the pain threshold was monitored. Capsaicin was applied to human skin once daily for 21 days, and the pain threshold was significantly increased after 10 days of application, and after 21 days the increase was found to be 260%. After termination of capsaicin treatment the thresholds were monitored for 21 days, and normalization occurred after 7 days. Argon laser stimulation is a reliable method to evaluate sensory and pain thresholds in human skin.

Administration, Topical↗
PubMed1989

Effect of antihistamines on argon laser-induced cutaneous sensory and pain thresholds and on histamine-induced wheal and flare.

A double-blind, randomized, placebo-controlled comparison of the analgesic and antihistaminic effects of four commonly used antihistamines (terfenadine, antazoline, diphenhydramine and cimetidine) was performed. Wheal and flare areas after histamine skin prick and sensory and pain thresholds induced by cutaneous argon laser irradiation were determined. Terfenadine, antazoline and diphenhydramine significantly reduced wheal and flare after histamine skin pricks. Only diphenhydramine increased the pain threshold to noxious cutaneous laser stimulations (22%) with a concomitant reduction of histamine wheal (61.5%) and flare (52.8%). The sensory threshold was not affected significantly. The antihistaminic and analgesic effects were not related.

Adult↗
PubMed1989

Continuous measurement of gastric blood flow by laser-Doppler flowmetry during gastroscopy.

Endoscopic laser-Doppler flowmetry (LDF) of gastric blood flow (GBF) was performed simultaneously with intragastric manometry to detect a possible correlation between GBF and luminal pressure during gastroscopy. By increasing luminal air pressure from 10 to 20 cm H2O a significant reduction in GBF was observed. Regional differences in GBF were also demonstrated. Variations in luminal air pressure have a significant influence on GBF as measured by LDF, and therefore intragastric manometry and standardization of intraluminal air pressure is necessary in endoscopic LDF measurements.

Adult↗
PubMed1989

Atopic dermatitis and the indoor climate. The effect from preventive measures.

Nine patients with atopic dermatitis (AD) were clinically evaluated before and after moving to new houses with improved air exchange, low relative humidity and optimal temperature control. During a 2-year period three clinical and subjective assessments were performed each month of disease activity, and compared with changes in suspended and respirable dust particles, room temperature, air exchange rate, concentration of house-dust mites in bedrooms, and the concentration of organic solvents in the indoor air. Ten matched patients with AD, who did not move, served as a control group. The skin condition of patients moved improved significantly after moving. The indoor climate was improved on: 1) air exchange rate, 2) relative humidity, and 3) room temperature, but the amounts of house dust mites, respirable air particles and organic solvents were unchanged. The clinical and subjective improvement in AD could not be correlated to any single indoor environmental factor. The present investigation supports the current concept, that AD may be a multifactorial disease, and that the indoor climate may be a contributing factor affecting the eczema.

Adolescent↗
PubMed1988

Reaction times to painless and painful CO2 and argon laser stimulation.

The introduction of lasers in pain research has made it possible to activate the nociceptive system without activating mechanosensitive afferents. In the present study the reaction times to painless and painful laser stimuli were studied to investigate if the reaction time to experimental pain is reproduceable. CO2 and argon lasers were used for stimulation, and the influence of stimulus (intensity and duration) and skin parameters (temperature, thickness, and reflectance) on reaction time were investigated. When these parameters were controlled the reaction times to painful CO2 and argon laser stimulation were within the same range (350-450 ms), and the intra-individual variability minimal (6.9%). The reaction time was used to estimate peripheral conduction velocity (10 m.s-1) for the activated fibre population when distinct pain was perceived. Determination of reaction times to non-painful and painful stimuli may be suitable ways to assess the functioning of thermal and nociceptive pathways.

Adolescent↗
PubMed1988

Selective averaging of argon laser induced pre-pain and pain related cortical responses.

The argon laser was found to be suitable for pre-pain and pain stimulation. The visible (488 and 515 nm) argon laser light penetrates the skin and is absorbed by melanin and haemoglobin. Argon laser stimuli of different intensities were perceived differently, and could be classified into 3 pre-pain and 3 pain classes. The pre-pain sensations were either perceived as warmth, weak pin prick, or weak pin prick followed by warmth. The pain sensations were perceived as painful pin pricks of different intensities. Single cortical responses to argon laser stimuli were averaged selectively, according to this perceptual classification, and characteristic pre-pain and pain related cortical responses were recorded. The sensation of warmth was related to a late cortical deflection, 700-800 ms after stimulus onset, whereas the pin prick related response appeared with a latency of 300-400 ms. Pre-pain related responses were only recorded when selective averaging according to perception was used. The amplitude of the selectively averaged pain related cortical responses correlated with the subjective sensation of pain. Selective averaging of pre-pain and pain related single responses may prove useful in studying the cortical projection of different perceptions or modality patterns, and to investigate the function of the thermal and nociceptive pathways and their interactions.

Adult↗
PubMed1988

No detectable increase in sister chromatid exchanges in lymphocytes from mycosis fungoides patients after topical treatment with nitrogen mustard.

We measured sister chromatid exchanges (SCEs) in lymphocytes of eight MF patients before, and 2 h, and 24 h after treatment with topical nitrogen mustard. The mean number of SCEs/cell (+/- SEM) were 8.15 (+/- 0.62), 8.34 (+0.55) and 8.26 (+/- 0.56), respectively. The 2 h and 24 h results do not differ significantly from pretreatment levels. Our results show that concentrations of nitrogen mustard used to control MF do not induce SCEs in peripheral blood lymphocytes.

Aged↗