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Biomedical subjects

P Bjerring

Publications and source records attributed to P Bjerring.

At least 127 records · Page 7Linked to original sources
PubMed1988

Sensory and pain threshold characteristics to laser stimuli.

The clinical applications of thermal sensory and pain thresholds have been very limited due to large intra-individual variations. In the present paper CO2 and argon lasers were used as thermal stimulators, and the different factors (stimulus parameters and skin conditions) affecting the thresholds are described. The intra-individual variations obtained in sensory (9.3%) and pain (4.3%) thresholds were very low, which suggests that the method can be applied for clinical purposes.

Adult↗
PubMed1988

Argon laser induced single cortical responses: a new method to quantify pre-pain and pain perceptions.

The shape (amplitude and latency) of single cortical responses to argon laser stimulation was found to match six perceptual classes: three pre-pain and three pain. The amplitude of the pain related single cortical responses correlated with the perceived feeling of pain. Easy detectable responses were obtained because habituation to the stimuli was reduced and a high degree of attention was given to each stimulus. Single cortical responses to argon laser stimuli are suggested as a new quantitative technique with application in the assessment of function in the thermal and nociceptive pathways.

Adult↗
PubMed1988

Argon laser treatment of cutaneous vascular lesions in connective tissue diseases.

Two patients with juvenile dermatomyositis, 5 with chronic discoid lupus erythematosus, and one with Rothmund-Thomson's Syndrome were treated for their teleangiectasias of the face with argon laser. The results were highly satisfactory with an almost normal appearance of treated skin in 4 patients. Two patients showed satisfactory results with 60-70% blanching, while 2 patients showed some improvement, but not a completely cosmetically satisfactory result. The most impressive results were in the patients with juvenile dermatomyositis and Rothmund-Thomson's Syndrome. The only side effects observed were a slight scarring and an insignificant pigmentation. No patient displayed any signs of disease activation.

Adolescent↗
PubMed1988

Skin blood flow in necrobiosis lipoidica during treatment with low-dose acetylsalicylic acid.

Skin blood flow was measured by the laser Doppler technique in lesional and clinically normal skin of 10 diabetic patients with necrobiosis lipoidica during and after treatment with 40 mg acetylsalicylic acid (ASA) daily. The measurements showed that the blood flow during ASA treatment was significantly decreased in the central lesional skin without changes in the peripheral part of the lesions and normal skin. In view of these findings we suggest that low-dose ASA may not be the best treatment for necrobiosis lipoidica.

Adolescent↗
PubMed1988

Laser-induced pain for evaluation of local analgesia: a comparison of topical application (EMLA) and local injection (lidocaine).

High-energy lasers are suitable for experimental pain stimulation because they selectively activate the polymodal nociceptors. Argon laser light penetrates deep into the skin and makes this laser type preferable for simulating pain arising from surgical skin incisions. Short argon laser pulses were applied to the skin and three parameters were quantified before and during analgesia; sensory threshold, pain threshold, and the pain-related cortical response (latency and amplitude). Determination of sensory and pain thresholds made it possible to distinguish between two levels of analgesia; the pain block, where no pain was felt but other sensations were still perceived; and total sensory block, where the laser stimulus elicited no sensations of any type. The analgetic effects of cutaneous injections of lidocaine and topical application of EMLA (eutectic mixture of local anesthetics) cream were evaluated and compared by means of the introduced parameters. Lidocaine produced total sensory block almost immediately after injection, which was associated with the absence of cortical response to cutaneous laser stimulation. When the EMLA cream was applied for 15 minutes, both sensory and pain thresholds increased. During the next 30 minutes after removal of the cream, the thresholds increased further. The increase in analgetic effect after removal of the cream was studied using different times (15, 30, 60, 80, 100, and 120 minutes) for topical EMLA cream application. Total sensory block was reached 20 minutes after removal of application for 80 minutes or immediately after removal of the cream after it was applied for 100 or 120 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1988

Hereditary hemorrhagic telangiectasia treated by laser surgery.

Hereditary hemorrhagic telangiectasia (Osler's disease) is a rare, inherited abnormality of the subepithelial vessels causing severe nose bleed as the most predominant symptom. The most efficient treatment has, until now, been dermoplasty of the nasal septum and cavity. There have been a few reports on treatment with CO2-, argon- or Nd-YAG-lasers, which have been encouraging. Ten patients with Osler's disease were treated for severe epistaxis. Three were treated with CO2-laser, two of these under general anaesthesia. Seven patients were treated with the argon laser under local anaesthesia. A variety of other sites were treated at the same time for functional or cosmetic reasons (mouth, face, fingers, rectum). Good results were obtained in eight cases. In three of the cases the observation period was more than two years. A second treatment has been necessary in three cases. Two other patients were treated recently, and it is too early to judge the results. The argon-laser is more convenient for this purpose than the CO2-laser. The method is quick and reliable and there is no need for hospitalization. The treatment can be repeated without permanent damage to the function of the nose.

Adult↗
PubMed1987

Intratumoural light distribution in an experimental mouse tumour irradiated by a diffuse-light irradiator compared with unilateral helium-neon light for photodynamic therapy.

Investigations on dosimetry in photodynamic therapy (PDT) of experimental mouse tumours transplanted into the right hind leg revealed a significant variability in the fluence rate reaching tumour cells in different parts of the tumour when irradiated by a 50 mW collimated He-Ne laser. Based on intratumoural fibre-optical light measurements, a new irradiation source was constructed, in which variability in the radiant energy fluence rate between different parts of the solid tumour was reduced. The new diffuse-light irradiator was constructed basically from two concentric water chambers surrounded by three linear 3000 W xenon flash lamps. The outer chamber was an optical band filter, and the inner chamber contained a light-dispersing solution of lipid droplets which created an isotropic light field in which the tumours were submerged for PDT. Compared with unilateral He-Ne laser irradiation, an enhancement factor of 7.3 in radiance was obtained for the diffuse-light irradiator measured in the tumour. The new apparatus provides a nearly isotropic light field for in vivo experimental PDT.

Animals↗
PubMed1987

Possible role of vacuum systems and compressed air generators in cross-infection in the ICU. A radioactive tracer study.

Cross-contamination between a hospital's vacuum and compressed air systems was demonstrated using xenon-133 as a tracer. A xenon-133 bolus was introduced to the vacuum system in the intensive care unit. Calculations based on the amount of radioactive tracer recovered from the compressed air outlet at the same location as that at which the tracer was introduced indicated that 17% of the tracer had entered the compressed air system. The contamination was caused because the vacuum and compressed air systems were located in the same machine room. This could conceivably provide a route for respiratory tract contamination in patients receiving ventilatory assistance with air-oxygen mixtures.

Air↗
PubMed1987

Methotrexate inhibits the human C5a-induced skin response in patients with psoriasis.

In this study we examined the effects of intradermal injections of human complement split product C5a in 10 patients with psoriasis in long-term treatment with methotrexate (MTX). The C5a was injected at the end of the weekly MTX cycle just before the intake of the first MTX dose and 3 h after the second of the 3 doses. The C5a-induced skin response was evaluated by measuring the diameter of the wheal and the area of the flare and by erythema index (EI), which was determined objectively by reflectance spectrophotometry. In all patients the skin response was significantly depressed when C5a was injected after MTX intake. The decrease of wheal, flare, and EI averaged 61.6%, 71.1%, and 57.5%, respectively, when all parameters were obtained at maximal skin response. The in vitro chemotaxis of peripheral blood neutrophils and monocytes from the patients toward C5a was markedly inhibited after intake of MTX (p less than 0.01). The skin biopsies obtained after C5a injection before intake of MTX revealed a perivascular inflammatory infiltrate and considerable dermal edema. After MTX intake the number of infiltrating leukocytes and the degree of dermal edema was markedly reduced. This study indicates that MTX is a potent inhibitor of C5a-induced skin inflammation, and that this inhibition may be caused by a direct effect on circulating neutrophils and monocytes. The results obtained in this work support the idea that anti-inflammatory effects of MTX may be partially responsible for its antipsoriatic effect.

Adolescent↗
PubMed1987

House dust mites and human dander.

The occurrence of house dust mites was measured in the homes of 12 patients with the scaly skin disease, psoriasis. The median number of mites in the mattress dust and floor dust was 27 (range 10-153)/0.1 g and 56 (range 12-114)/0.1 g respectively, which is significantly higher than the background pollution of house dust mites in normal Danish homes. The results support the idea that the amount of mites in our homes not only depend on relative air humidity but also on the production of dandruff.

Adult↗
PubMed1987

A suction blister method that gives epidermal biopsies from mice of different ages, suitable for histologic studies of Langerhans cells.

A modified suction blister device has been developed. It allows in vivo retrieval of 3 x 3 mm2 mouse epidermis biopsies. Separation takes place exactly at the epidermal-dermal junction. Young skin and iso-grafted skin require suction with a lower bar value than skin from young and old non-grafted animals. Langerhans cells in biopsies were identified both with ATPase staining and with monoclonal antibody. Suction blisters produce Langerhans cell counts similar to those obtained on EDTA-separated epidermis.

Aging↗
PubMed1987

Syngrafting skin among mice of similar and different ages increases the number of Langerhans cells and decreases responsiveness to 1,4-dinitrofluorobenzene.

Counting on suction blister skin biopsies, the number of Langerhans cells per mm2 in BALB/c mouse epidermis was found identical in 1-, 11-, and 22-month-old animals, but consistently elevated in syngrafted skin 10 months after transplantation. This effect of grafting was independent of whether young or old skin was transferred to young or old recipients. Skin swelling induced by dinitrofluorobenzene (DNFB) sensitization was reduced in 22-month-old non-grafted mice and in grafted skin irrespective of donor and recipient age.

Aging↗
PubMed1987

Skin reflectance spectrophotometry.

A skin reflectance spectrophotometer was constructed for determination of colour changes in dermatological disorders. Objective quantification of human skin colour in vivo can be achieved with this apparatus. The spectrophotometer is of simple construction, and it has improved reproducibility compared to previously described instruments. Reproducibility is better than 1.7%, measured in comparison to a standard white 100% reflecting surface. Due to 1) the short scan time of 20 s, 2) small and mobile measuring head, and 3) the use of optical fibers for delivering and detecting light, the apparatus is suited for clinical spectral colour measurements and comparison of different treatment effects in most anatomical regions. By use of computer technology, it is possible to make fast and reliable comparisons of spectrograms, and to perform chromophore analysis from the recorded data.

Adult↗
PubMed1986

Bacterial contamination of compressed air for medical use.

The present study demonstrates a previously unnoticed source of bacterial contamination of locally manufactured compressed air for medical use. Air samples were drawn into a specially constructed device, and bacterial contents were identified from growth on agar plates. Various factors contributing to bacterial contamination of compressed air during production are mentioned and preventive measures are discussed.

Air Microbiology↗
PubMed1986

Comparison of microbiological contents of compressed air in two Danish hospitals. Effect of oil and water reduction in air-generating units.

In a comparative study microbiological contamination of compressed air for medical use produced in oil-lubricated and oil-free compressors was investigated. Significantly lower levels of bacterial contamination were observed in the air produced by oil-free compressors; but if the air is transported to operating rooms and intensive care units through extensive pipeline systems previously contaminated by oil-lubricated compressors, the bacterial count at peripheral air outlets remains unchanged.

Air Microbiology↗
PubMed1986

Benoxaprofen in treatment of systemic sclerosis.

Ten patients with systemic sclerosis were treated with benoxaprofen, a potent lipoxygenase inhibitor, for a period of 6 months. In an attempt to evaluate the efficacy a number of physical disease parameters were followed during the trial. None of these parameters revealed any significant differences. There was, however, a trend for a change towards normalisation of a defect monocyte chemotaxis. In view of the slow and progressive nature of systemic sclerosis the present study leaves undetermined whether benoxaprofen exerts a beneficial effect on systemic sclerosis.

Adult↗