Biomedical subjects
Publications and source records attributed to T Agner.
A case of simultaneous occurrence of lichen planus (LP) and hepatitis C in the same patient is presented. The patient had received treatment with interferon alpha for her chronic liver disease, and the association between LP, hepatitis C and interferon alpha treatment is discussed.
The properties of urea as an irritant were investigated. Seventeen healthy volunteers were patch tested with 20% urea using petrolatum and water, respectively, as vehicles. Irritant effects of urea were assessed by clinical evaluation of patch test reactions as well as by various non-invasive methods. The inflammatory response was quantified by laser Doppler flowmetry measuring the superficial blood flow, and by ultrasound A-scan reflecting the edema formation. Impairment of the barrier function was indicated by measurement of transepidermal water loss (TEWL). It is concluded that 20% urea in petrolatum applied under occlusion for 24 h elicits significant inflammation (i.e. increase in blood flow and skin thickness) and causes impairment of the skin barrier (i.e. increased TEWL). The irritant impact of urea on the skin depends upon the vehicle used, the irritant effect being intensified when urea is dispensed in petrolatum compared with water.
The aim of the study was to assess the susceptibility of clinically normal skin to a standard irritant trauma under varying physiological and patophysiological conditions. Evaluation of skin responses to patch tests with sodium lauryl sulphate (SLS) was used for assessment of skin susceptibility. The following noninvasive measuring methods were used for evaluation of the skin before and after exposure to irritants: measurement of transepidermal water loss by an evaporimeter, measurement of electrical conductance by a hydrometer, measurement of skin blood flow by laser Doppler flowmetry, measurement of skin colour by a colorimeter and measurement of skin thickness by ultrasound A-scan. The studies were carried out on healthy volunteers and patients with eczema. In the first studies the standard irritant patch test for assessment of skin susceptibility was characterized and validated. SLS was chosen among other irritants because of its ability to penetrate and impair the skin barrier. The implications of use of different qualities of SLS was investigated. The applied noninvasive measuring methods were evaluated, and for quantification of SLS-induced skin damage measurement of TEWL was found to be the most sensitive method. Application of the standard test on clinically normal skin under varying physiological and patophysiological conditions lead to the following main results: Seasonal variation in skin susceptibility to SLS was found, with increased susceptibility in winter, when the hydration state of the stratum corneum was also found to be decreased. A variation in skin reactivity to SLS during the menstrual cycle was demonstrated, with an increased skin response at day 1 as compared to days 9-11 in the menstrual cycle. The presence of active eczema distant from the test site increased skin susceptibility to SLS, indicating a generalized hyperreactivity of the skin. Taking these sources of variation into account healthy volunteers and patients with hand eczema and atopic dermatits were studied and compared. In healthy volunteers increased baseline TEWL and increased light reflection from the skin, interpreted as "fair" skin, was found to be associated with increased susceptibility to SLS. Hand eczema patients were found to have fairer and thinner skin than matched controls. Increased susceptibility to SLS was found only in patients with acute eczema. Patients with atopic dermatitis had increased baseline TEWL as well as increased skin susceptibility as compared to controls. Skin susceptibility is thus influenced by individual- as well as environment-related factors. Knowledge of determinants of skin susceptibility may be useful for the identification of high-risk subjects for development of irritant contact dermatitis, and may help to prevent the formation of the disease.
The pituitary glycoprotein hormones thyrotropin (TSH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) consist of two noncovalently linked subunits, alpha and beta. In addition to producing intact hormone, the pituitary releases free alpha-subunit, which is stimulated by gonadotropin-releasing hormone (GnRH) and thyrotropin-releasing hormone (TRH). However, little is known about the dopaminergic regulation of free alpha-subunit in vivo. The effect of dopamine (DA), metoclopramide (MTC), and the specific DA D-1 receptor agonist, fenoldopam, on circulating alpha-subunit levels was studied in normal men and women. Normal women received 4-hour infusions of either glucose (n = 6) or DA at rates of 0.04 (n = 6), 0.4 (n = 6), and 4.0 micrograms/kg.min (n = 6). After 3 hours, 10 mg MTC was administered intravenously (IV). The high dose of DA significantly lowered alpha-subunit levels (P less than .05). No response to MTC was observed in any of the groups. Six women received glucose or DA infusion (4.0 micrograms/kg.min) for 18 hours. DA significantly reduced basal alpha-subunit levels compared with control infusion (P less than .05). MTC administration after 17 hours induced a significant increase in alpha-subunit levels on the day of DA infusion compared with control (P less than .05). In a third study, nine normal males received fenoldopam (0.5 microgram/kg.min) or placebo infusions for 4 hours. Fenoldopam did not affect basal alpha-subunit levels, but the alpha-subunit response to a GnRH/TRH bolus was significantly increased during fenoldopam compared with control (P less than .05). The results suggest that alpha-subunit release may be modulated by the dopaminergic system in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)
The hypothesis was tested that a cyclic variation exists in skin reactivity to irritant stimuli. Twenty-nine healthy women with regular menstrual cycles were challenged with sodium lauryl sulfate as an irritant patch test at day 1 and at days 9 through 11 of the menstrual cycle. The skin response to the applied irritant stimulus was evaluated by visual scoring and also quantified by measurements of transepidermal water loss, edema formation, and blood flow in the skin. The skin response to challenge with sodium lauryl sulfate was found to be significantly stronger at day 1 than at days 9 through 11 in the menstrual cycle as evaluated by visual scoring (p less than 0.05) as well as by measurement of transepidermal water loss (p less than 0.05) and edema formation (p less than 0.005).
Basic physiological characteristics were examined in the uninvolved skin of 39 patients with hand eczema and in 39 healthy controls. Susceptibility to sodium lauryl sulphate (SLS)-induced irritant dermatitis was evaluated by the application of a single 24-h SLS patch test to the upper arm. Transepidermal water loss (TEWL) was measured by an evaporimeter, skin thickness by ultrasound A-scan, blood flow by laser-Doppler flowmetry and skin colour by a chroma meter using the L*a*b* system of the Commission Internationale de l'Eclairage (CIE). No difference in basal TEWL values was found between patients and controls. A decreased skin thickness was found in those with hand eczema as compared to the controls. The hand eczema patients had significantly increased L* and decreased b*-values compared to controls, indicating a more 'fair' skin. Susceptibility to SLS was increased only in patients with acute eczema, indicating that the presence of an active eczema increases the reactivity to irritants of distant uninvolved skin.
The influence of basal transepidermal water loss (TEWL), skin thickness, blood flow and skin colour on susceptibility to sodium-lauryl-sulphate(SLS)-induced irritant contact dermatitis was studied in 70 healthy volunteers. SLS 0.5% was applied as a patch test. For assessment of basal values and skin response to SLS, bioengineering methods were used: TEWL was measured by an evaporimeter, skin thickness by ultrasound A-scan, blood flow by laser Doppler flowmetry, and skin colour by a colorimeter, using the L*a*b* system of the Commission Internationale de l'Eclairage (CIE). By use of multiple regression analysis, it was demonstrated that basal TEWL was substantially related to skin susceptibility to SLS, high basal TEWL predicting an increased susceptibility to SLS. Also increased light reflection from the skin, indicating a 'fair' skin, was found to be associated with increased susceptibility to SLS.
Basal transepidermal water loss, skin thickness, blood flow and skin colour were examined before and after exposure of 28 patients with atopic dermatitis and 28 healthy controls to sodium lauryl sulphate. Transepidermal water loss was measured with an evaporimeter, skin thickness by ultrasound A-scanning, blood flow by laser Doppler flowmetry and skin colour by a chroma meter using the L*, a* and b* values, respectively. Patients with atopic dermatitis were found to have higher basal transepidermal water loss than controls (p less than 0.0001), and had an inclination towards an increased basal skin thickness (p = 0.056). No statistically significant differences were found with respect to basal blood flow or skin colour. The skin response to sodium lauryl sulphate was found to be statistically significantly increased in atopic patients compared with controls when evaluated by visual scoring and by increase in skin thickness, but not by increase in transepidermal water loss, blood flow or skin colour.
The dose-response relationship in patch testing with sodium lauryl sulphate (SLS) was studied. The irritant skin response was quantified by visual scoring as well as by the following noninvasive methods: measurement of transepidermal water loss (TEWL) by an evaporimeter, measurement of skin color by a colorimeter, measurement of superficial blood flow by laser Doppler flowmetry, and measurement of edema in the skin by ultrasound A-scan. Twelve volunteers were patch tested with 0.12, 0.25, 0.50, and 1.00% SLS, and the skin response was evaluated after 24 and 48 h, respectively. We found a statistically significant linear dose-response relationship between dose of SLS and skin response evaluated by measurement of TEWL, skin color, superficial blood flow, and edema. Statistical evaluation by regression analysis proved measurement of TEWL to be the method best suited overall for quantification in relation to patch testing with SLS, whereas colorimetry was found to be the least sensitive of the applied methods. Ultrasound A-scan was found to be a promising method for quantification of the inflammatory response, being consistently more sensitive than measurement of skin color.
A major purpose of irritant patch testing is to differentiate between normal, delicate and less sensitive skin. To assess the usefulness of irritant patch testing, knowledge of variation in responses to identical patch tests is essential. In the present study inter- and intra-individual variation in irritant patch test reactions due to sodium lauryl sulphate and nonanoic acid is given when evaluated by traditional visual scoring as well as different non-invasive methods, i.e. measurement of transepidermal water loss, the hydration state of stratum corneum by electrical conductance, cutaneous blood flow by laser Doppler flowmetry, and measurement of skin thickness by 20-MHz ultrasound A-scan. The intra-individual 'site-to-site' variation was considerably less than the inter-individual variation, which is essential to differentiate between persons with delicate and less sensitive skin. Methods used were relevant for this purpose except for the measurement of electrical conductance.
A 54-year-old woman with multiple tender angiolipomata was treated with intravenous infusions of lignocaine (5 mg/kg) in saline in a double-blind trial. The pain disappeared but reappeared gradually 3 weeks later. Central mechanisms may explain the mode of action of lignocaine. Infusions should be carried out during cardiac monitoring.
Erythema elicited by the local irritant sodium lauryl sulphate was studied in comparison with unexposed skin. Colour coordinates of the CIE system were recorded using two commercially available colorimeters. With both colorimeters a positive movement of the alpha-axis (toward red, P less than 0.001) and a negative movement on the L-axis (toward dark, P less than 0.01) were registered. Technical and in-vivo experimentation showed the two pieces of equipment to be accurate. However, a simple conversion factor cannot be established. Both pieces of equipment correlated positively with clinical scoring of erythema and with measurement of cutaneous blood flow by laser-Doppler flowmetry. In conclusion, the two colorimeters appeared comparable. Colorimetry by the CIE system, which takes into account the non-linear colour perception of the human eye, was found useful with potential value in both experimental and clinical dermatology. The techniques appeared suitable for routine testing.
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This report reviews individual-related variables, environment-related variables and instrument-related variables, with a focus on the Evaporimeter EP1 (ServoMed). Start-up and use is described, and guidelines for good laboratory practice given.
To clarify the sources of variation in irritant patch testing, variability in delivery of the test substance from the patch test system was studied. An in vitro model was used to study the penetration of sodium lauryl sulphate (SLS) from a patch test system into the skin. Different formulations of SLS applied to the skin for 24 h were studied (aqueous solution and gels), but irrespective of the vehicle used permeation of SLS into the recipient phase was poor. Results were compared to in vivo patch testing in 12 subjects. Approximately 70% of the applied SLS in aqueous solution was released from the patch test system. Release from gels was poorer. High concordance between the in vivo and the in vitro model was found. No correlation was found between the amount of SLS left in the filter disc and the strength of the clinical reaction in vivo.
In order to investigate a possible seasonal variation in the skin response to irritants, 17 healthy volunteers were patch tested with sodium lauryl sulphate (SLS) and nonanoic acid in the winter and summer. The response to these irritants was quantified by visual scoring, measurement of transepidermal water loss, measurement of electrical conductance indicating the hydration state of the superficial epidermis, measurement of blood flow by laser Doppler and measurement of oedema by ultrasound A-scan. Significantly stronger reactions to SLS were found during the winter than the summer as indicated by visual scoring and by measurements of transepidermal water loss, whereas no significant seasonal variation was found in the response to nonanoic acid. A decreased hydration state of the epidermis of unexposed skin was found during the winter, and we believe this to be responsible for the increased susceptibility to SLS during this season.
The transonychial water loss (TOWL) was measured in 21 healthy volunteers with an evaporimeter, to establish the usefulness of this technique and study the influence of sex, age and nail-plate thickness. The median TOWL was 19.4 g/m2 h-1 and it decreased with increasing age (R = 0.51, P less than 0.018). The median transepidermal water loss (TEWLHAND) from the back of the hand was 16.0 g/m2 h-1 and from the dorsal side of the underarm (TEWLARM) it was 5.6 g/m2 h-1. The TEWLARM was significantly less than from any of the two other points studied (P less than 0.01), while there was no significant difference between the values obtained on the hand and the nail. TEWLARM had a median value of 6.4 g/m2 h-1 in men and 4.3 g/m2 h-1 in women (P less than 0.05) in this study. No significant correlation between nail-plate thickness, as measured by ultrasound 20 MHz A-scan, and TOWL was found. Measurements of TOWL are of interest and should be age-related. Further studies are needed to determine TOWL in various forms of nail pathology.
An increased frequency of thyroid autoantibodies has been reported in patients with palmar and plantar pustulosis (PPP). This study was undertaken to determine the frequency and type of thyroid disease in 32 patients with this disease compared with a control group. Thyroid disease was demonstrated in 53% of the patients with PPP as compared to 16% in the matched control group. Fourteen patients with PPP had an enlarged thyroid and in six there were thyroid autoantibodies. There appears to be an increased incidence of goitre and thyroid autoantibodies in PPP with a decrease in the level of the thyroid hormones.