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Biomedical subjects

B Bjarnason

Publications and source records attributed to B Bjarnason.

At least 19 recordsLinked to original sources
PubMed2000

Effect of dark test-substance pigmentation on skin perfusion assessments and effect of test technique on balsam of Peru patch-test results.

13 balsam of Peru (Myroxylon Pereirae) patch-test-positive subjects are re-tested with 25% balsam of Peru in petrolatum and with serial doses printed on polyester squares. All substances are applied with tape strips for 3, 6, 24 (1 day [D]), 48 (2D), 72 (3D) and 96 h (4D) on each subject and for 96 h (4D) with plastic foils. Tests are followed visually and with perfusion assessments from 3 h to 9 days. Results show that pigment remnants following detachment of patches affect perfusion assessments. Such effect due to pigment is supported by readings of patch tests through the petrolatum test substance while applied with transparent foils. For most reactions, good agreement is observed between the assessment techniques when peak assessment values of reactions are compared. There is inter-individual variation in perfusion with identical tests. With the petrolatum test substance, increased visible reactivity was observed when the application time was extended up to 24 h (1D), while extension of application time increased perfusion in most cases except for an extension from 24 (2D) to 48 h (4D) where decreased perfusion resulted in most cases. Dose and application time did not affect the timing of highest reactivity of reactions in most cases.

Adult↗
PubMed2000

Assessment of balsam of Peru patch tests.

To find an ideal test technique for as low a dose of balsam of Peru (Myroxylon Pereirae) as possible, subjects testing positive to balsam of Peru are re-tested with a 25% concentration of balsam of Peru in petrolatum. Applications are with Finn Chambers for 6 different application times, and directly by foils for 96 h (4 days (D)). The goals are to confirm which subjects are positive and which are not, and, using that information, to see if it is possible to distinguish between these 2 groups, tested concomitantly at much lower serial dose levels, in terms of perfusion or by visual assessments. 5 different serial doses are applied with strips for 3-96 h (4D) and with foils for 96 h (4D). The Finn Chamber tests allow a distinction between visually positive and negative subjects supported by perfusion assessments. With the foils, a 24x lower serial dose level than with the 25% test substance is sufficient to distinguish between positive and negative subjects in terms of perfusion values. This approach requires readings up to 9 days. With this test, the visual approach yields only 3 of 10 positive subjects. This study demonstrates that a lower test dose is possible with perfusion assessments compared to visual ones.

Adult↗
PubMed2000

Effect of test techniques of perfusion of neomycin sulfate patch tests. A comparative study with visual assessments.

Effects of test techniques on neomycin patch test results have not been thoroughly investigated. This study focuses on effects of dose and application time of neomycin sulfate patch tests on test results. The effects are assessed both visually and by perfusion. 16 subjects positive to neomycin are retested with neomycin sulfate in various doses and vehicles applied with different application devices for variable time intervals. All subjects were tested with a serial-dose series for time intervals ranging from 3 to 96 h (4 days [D]). The results show very good agreement between perfusion assessments and positive and negative visual assessments of reactions; however, a gray zone was detected where reactions with variable perfusion were associated with visually questionable test responses. 1:27 serial dilutions and wide application time intervals show a positive response with perfusion assessments and partly with visual assessments. Regardless of reading technique, highest reactivity of reactions was detected at either 96 h (day [D] 4) or 168 h (D7) in each subject with minor exceptions, regardless of dose, vehicle, application device or application time. Some findings of the study support the idea that reactions with papules alone are positive tests. Possible effect of tapes and foils on test results are discussed.

Adult↗
PubMed2000

Patch testing with neomycin sulfate.

The recommended patch test concentration of neomycin sulfate is 20% in petrolatum applied occluded for 48 h (2 days [D]). In the current study, the efficiency of such a test is compared to results with other techniques using lower allergen dose than obtained by approximately 20 microl of the 20% substance. Efficiency of petrolatum and demineralized water as vehicles are compared. 16 neomycin-sulfate positive subjects were retested with serial doses ranging from 0.4 to 0.0085 mg/cm2 neomycin sulfate in cellulose printed on polyester squares and applied by both tapes and plastic foils. Additionally, tests were performed with the 20% petrolatum substance in Finn Chambers. Tests containing the 20% substance in petrolatum and in water were applied directly with transparent foils. Readings ranged from 3 to 264 h (11D) following applications. Results show that foil applications of a polyester square dose, that is 7% of the dose obtained with the 20% substance, distinguished between perfusion of subjects who were visually positive and not with any test in the study. With the same test technique and visual assessments, 2 subjects were false-negative but developed doubtful test responses with the Finn Chambers.

Dermatitis, Allergic Contact↗
PubMed2000

Sensitization versus elicitation in allergic contact dermatitis: potential differences at cellular and molecular levels.

The induction and elicitation phases of allergic contact dermatitis are very complicated processes that differ in many respects. Many issues remain to be investigated, especially in the elicitation phase of this disease. Several key molecules involved in the development and maintenance of allergic contact dermatitis have already been defined, including a number of different cytokines and adhesion molecules. Attempts are being made to develop new, more specific pharmacologic and immunologic inhibitors of their activity. Because patients who see a doctor are already sensitized, further elucidation of the factors affecting the elicitation of allergic contact dermatitis will greatly contribute to the prevention and treatment of the disease.

Cell Adhesion Molecules↗
PubMed1999

Childhood, neonatal, and stillborn pemphigus vulgaris.

BACKGROUND: Childhood, neonatal, and stillborn cases of pemphigus vulgaris were reviewed. METHODS: From an examination of the pemphigus vulgaris literature, 46 childhood cases, nine neonatal cases, and three stillborn cases were found and investigated. RESULTS: In the childhood cases, the ratio between the sexes is approximately the same. The mean age of onset is 12 years, with only 11 children being 10 years of age or younger. Some children were treated with adjuvants to corticosteroids, most of them with azathioprine. While only one childhood case has been reported as fatal, the long-term prognosis and the relationship of early treatment and outcome are unknown. Neonatal prognosis, however, is excellent. Both neonatal and stillborn cases are probably the result of transplacental transmission of maternal antibodies. The connection between maternal antibody titer and fetal mortality is unknown. All stillborn cases reviewed died during the eight month of gestation. Immunosuppressive treatment probably affects fetal survival. In women with an active disease, who have had the disease, or who are monozygotic siblings to such patients, the possibility of the fetus developing the disease must be considered. CONCLUSIONS: It is essential that physicians be aware of the existence of childhood pemphigus vulgaris in order to make an early diagnosis and to avoid treatment delay. More childhood case reports are needed to obtain better information on optimal treatment, and authors should be encouraged to report the follow-up of their cases.

Adolescent↗
PubMed1999

Unusual skin reaction to silicone content in breast implants.

We present a patient who had a long history of unsuccessful bilateral mammary operations with insertion and extraction of various implants, some of which were filled with silicone gel, others with saline. In addition to complications in the tissue surrounding the prosthesis, she had distant widespread skin lesions which, we believe, were due to leakage from the implant. A cutaneous test with material from various implants, such as the gel content and the shells, caused an unusually prolonged inflammatory response, which was difficult to classify as being either irritative or allergic. Macromorphologically and histologically, the provoked lesions resembled the previous cutaneous lesions. We believe that the patient's complications are due to an unusual host response to silicone.

Breast Implantation↗
PubMed1999

Influence of patch-test application tape on reactions to sodium dodecyl sulfate.

There remains much room for improvement in the accuracy of the patch test procedure. There has been a lack of knowledge regarding the possible relationship between the intensity of test reactions and the quality of the tape used to apply patch tests. Using different brands of tape, patches coated with 2 mg/cm2 sodium dodecyl sulfate (SLS) were applied for 24 h to the backs of 10 volunteers. The tape specimens varied in terms of manufacture, elasticity, adhesive strength, and water permeability. The intensity of patch test reactions, evaluated visually and objectively with both the high resolution laser Doppler perfusion imaging technique (HR-LDPI) and transepidermal water loss measurements (TEWL), varied significantly with the different brands of tape. Observed variations in the intensity of reactions to the patch tests could not be explained by any of the 4 tape parameters investigated. In order to attain optimal test quality in the future, both the tape and patches used in the testing system should be standardized and clearly labelled.

Adhesives↗
PubMed1999

Objective non-invasive assessment of patch tests with the laser Doppler perfusion scanning technique.

The laser Doppler perfusion scanning technique is an objective, non-invasive assessment method that may be used to assess patch tests. The purpose of this paper is to focus on its clinical use in individuals with light skin, tested with non-pigmented test materials. A laser Doppler perfusion imager PIM 1.0 (LDPI) is used to study different set-ups of the instrument that may affect readings. These set-ups are studied through simulated light-absorbing patch tests. The results have served as a base for clinical experiments comparing visual and LDPI assessments of normal skin, irritant patch-test reactions, and more than 25,000 allergic patch-test assessments of reactions of different intensities and control patches. This paper reviews the clinical experiments to suggest a set-up of the LDPI for patch-test readings. Such a set-up makes it possible to compare intra- and inter-individual test results and to obtain meaningful assessment values among users. Some subject-related factors that may affect reading results are studied, and the effect of non-subject related factors on readings are considered. Use of the technique is illustrated by images of perfusion and a perfusion profile of a patch-test reaction followed over time.

Anti-Inflammatory Agents↗
PubMed1999

Assessment of budesonide patch tests.

Patch-test technique for budesonide needs improvement. 20 subjects with positive or questionable patch-test responses to budesonide were retested for 3 to 96 h (4 days [D]) with polyester patches coated with budesonide in serial doses (150 to 0.074 microg/cm2). Multiple readings were taken visually and with a laser Doppler perfusion imaging technique up to 264 h (day [D]11). Additionally, all subjects were tested with 0.1% budesonide in petrolatum in Finn Chambers for 48 h (2D) with readings taken at 72 (D3), 96 (D4) and 168 h (D7). Different dose levels and application times affected unpredictably highest assessments of reactions. No clear suppression of reactivity was observed at high doses. Time points of highest assessments of reactions varied between subjects but were generally the same for each subject with both reading methods regardless of dose levels or application times. Positive and negative subjects during the study were easily distinguished with all serial doses, regardless of assessment technique. At 2.0 microg/cm2, the lowest dose level tested on all subjects, longer applications than 24 h (1D) were required to detect all positive subjects. 48-h (2-D) applications required 2 readings, optimally at 96 (D4) and 216 h (D9). The only test technique with Finn Chambers used here did not make such distinction possible.

Adolescent↗
PubMed1999

Reactivity at edges of corticosteroid patch tests may be an indicator of a strong positive test response.

BACKGROUND: The importance of the reactivity at the edges of corticosteroid patch tests is unknown. OBJECTIVE: To study the clinical importance of edge reactivity in budesonide patch tests. METHODS: Ten subjects previously positive for budesonide patch tests were retested with 0.1% budesonide in Finn Chambers((R)) and with budesonide-printed polyester squares in serial doses (150-0.074 microg/cm(2)). Six exposure periods were used for each polyester square dose (3 h to 4 days). Tests were followed up to 11 days. Doubtful or weakly visible reactivity at the test edges was assessed additionally by test perfusion assessments. RESULTS: Nine of 10 subjects reacted with some edge reactivity and later exhibited positive reactions. Perfusion assessments helped to confirm early edge reactivity. Some allergic subjects showed edge reactivity only at high doses, while longer applications were required for weaker doses. CONCLUSION: Edge reactivity may be an indicator of a strong suppressed test response.

Administration, Topical↗
PubMed1998

An immunological interleukine-6 capacitive biosensor using perturbation with a potentiostatic step.

An instrument for potentiostatic capacitance measurements, based on perturbation with a potentiostatic step was used. The capacitive sensor consisted of self-assembled sulfur compounds on gold to which antibodies towards Interleukine 6, Il-6, had been immobilized. The biosensor was part of a potentiostatic three-electrode system with an extra reference electrode. Two different methods using epoxy- or carbodiimide coupling of the polyclonal antibodies were compared. The antigen Il-6 could be detected from 5 x 10(-16) to 5 x 10(-13) M with one immobilization method and to more than 5 x 10(-9) M with the other. No labels were necessary since the binding of the antigen was detected directly. The insulating properties of the different layers of the biosensor were investigated.

Biosensing Techniques↗
PubMed1998

Objective assessment of nickel sulfate patch test reactions with laser Doppler perfusion imaging.

The laser Doppler perfusion scanning technique was used to assess the superficial blood flow of nickel sulfate hexahydrate patch test reactions. There was good agreement between laser Doppler and visual assessments when the highest assessment values of reactions were studied. Earlier detection of reactions was possible with the laser technique. There was great inter-individual variance in perfusion between identically tested patients. 4 patients were visually negative when a TRUE Test patch test dose of 0.20 mg/cm2 was applied for 48 h and the test area read 4x up to 168 h. These 4 showed a dose-related increase in perfusion and visually positive reactions using longer application times. The instrument allowed a dose reduction not possible for visual assessments. Reading transparent patches in contact with the skin through transparent semi-occlusive plastic foil or through windows in the tape strip over the patches, allowed us to detect perfusion at 48 h, where a longer application would have been needed using tape and visual assessments.

Adult↗
PubMed1998

Visual and laser Doppler perfusion scanning assessments of Kathon CG patch test reactions.

BACKGROUND: Testing procedure for Kathon CG (Diagnostics AB, Tygelsjö, Sweden) is not standardized. OBJECTIVE: To improve test results for Kathon CG. METHODS: Eleven subjects were tested with Kathon CG patch tests applied from 6 to 96 hours. Tests were read visually and by a laser Doppler perfusion scanning technique at time points ranging from 6 to 240 hours. RESULTS: There were large differences in the perfusion profiles of subjects tested in identical fashion. Beginning reactions were detected earlier with the laser Doppler scanning than with the visual assessment technique. There was no obvious agreement between peak perfusion values of reactions and application times. Both assessment techniques were effective at distinguishing between positive and negative subjects at an adequate dose and application time. This distinction was possible using a shorter reading time with the laser Doppler scanning for all subjects. Six-hour applications were sufficient to detect all positive subjects so tested regardless of assessment technique. With that application time, positive and negative subjects were most effectively identified using long reading times regardless of assessment technique. CONCLUSION: The shortest application time used on all subjects, 24 hours, was effective and 6-hour applications with long reading times for all subjects so tested. Doses lower than 0.0040 mg/cm2 resulted in false-negative tests.

Adult↗
PubMed1996

Sensitizing and irritant properties of 3 environmental classes of diesel oil and their indicator dyes.

3 dyes, Solvent Yellow 124 and Solvent Blue 79 or Solvent Blue 98, were added to diesel oils in Sweden for identification of their particular use and taxation bracket in late 1993. Health concern regarding the toxicity of the dyes resulted in several reports to the Worker Inspection Bureau. 36 men reporting skin disease supposedly caused by dyes were diagnosed to have irritant reactions, irritant contact dermatitis or exacerbation of other skin disease. Tests on 15 individuals from this group, and 20 healthy volunteers, failed to demonstrate contact allergy or contact urticaria to the dyes or dyed diesel oil. Patch tests with dyes (10% v/v) in pet. did not cause irritation. Tests of irritant properties of the diesel oils showed that the old type of oil, with high viscosity, high content or aromatic compounds and moderately high sulfur content, caused little irritation, whereas newer, lighter qualities of diesel oil, with low concentrations of aromatic compounds and low sulfur content, which cause less pollution to the environment when burnt, were significantly more irritant to the skin and probably a cause of the skin problems.

Adult↗
PubMed1995

Family study of atypical nevi with investigation of heparin sulfate proteoglycan.

BACKGROUND: The epidemiology of atypical nevi (AN) is currently obscure; however the diagnosis must be made early in order to follow these individuals and treat any melanomas that may arise at an early stage, thus preventing premature death. MATERIALS AND METHODS: Following the guidelines of the NIH on clinical and histologic features of ANS, 38 adult members in 8 families were investigated. Twenty-seven were physically examined and 25 biopsied. Biopsies from ANS and junctional nevi from unrelated persons were also stained with antibodies against heparan sulfate proteoglycan (HSPG). RESULTS: At least 21 of 38 members had ANS. Staining with HSPG antibodies did not differentiate between ANS and benign junctional nevi, all showing slightly irregular staining. In seven of eight families, two or more family members were affected by ANS. CONCLUSIONS: Although it is not known whether or not HSPG plays a role in melanomas becoming invasive, or the potential of melanoma developing in ANS there were no differentiating features of staining in ANS, and junctional nevi to help in the differential-diagnosis of the two.

Adult↗