Biomedical subjects
Flemming Madsen
Publications and source records attributed to Flemming Madsen.
IgG antibodies against microorganisms and atopic disease in Danish adults: the Copenhagen Allergy Study.
BACKGROUND: Seropositivity to food-borne and orofecal microorganisms (hepatitis A virus, Helicobacter pylori, and Toxoplasma gondii ), which are considered to be markers of poor hygiene, has been reported to be associated with a lower prevalence of atopy. In contrast, colonization of the gut with Clostridium difficile, a potential intestinal bacterial pathogen, in early childhood may be associated with a higher prevalence of atopy. OBJECTIVE: The objective of this study was to investigate the association between atopy and exposure to 2 groups of food-borne and orofecal microorganisms: (1) markers of a poor hygiene and (2) intestinal bacterial pathogens. METHODS: A cross-sectional population-based study of 15- to 69-year-olds living in Copenhagen, Denmark, was carried out in 1990 to 1991. Atopy was defined as a positive test result for specific IgE to at least 1 of 6 inhalant allergens. Exposure to microorganisms was assessed as IgG seropositivity to microorganisms. RESULTS: Seropositivity to 2 or 3 markers of poor hygiene (hepatitis A virus, H pylori, and T gondii ) was associated with a lower prevalence of atopy (adjusted odds ratio, 0.5; 95% CI, 0.3 to 0.8). In contrast, seropositivity to 2 or 3 intestinal bacterial pathogens (C difficile, Campylobacter jejuni, and Yersinia enterocolitica ) was associated with a higher prevalence of atopy (adjusted odds ratio, 1.7; 95% CI, 1.2 to 2.6). CONCLUSION: Exposure to markers of poor hygiene was associated with a lower prevalence of atopy, whereas exposure to intestinal bacterial pathogens was associated with a higher prevalence of atopy. These findings raise the hypothesis that different groups of food-borne and orofecal microorganisms may have different effects on the risk of atopy.
Smoking might be a risk factor for contact allergy.
BACKGROUND: Contact allergy is a major public health problem in industrialized countries. Hitherto, known risk factors for contact allergy have mainly included increased exposure to allergens. There are no published data on the relation between smoking and contact allergy. OBJECTIVE: To investigate the association between smoking and contact allergy. METHODS: The study population comprised a cross-sectional, general population-based sample of 15- to 69-year-old persons living in Copenhagen, Denmark. A total of 1056 persons (73.6% of the invited) were given a patch test (TRUE test). Contact allergy was defined as a positive patch test result to at least 1 of 23 allergens. Nickel contact allergy was defined as a positive patch test reaction to nickel. Allergic nickel contact dermatitis was defined as a history of eczema on exposure to metallic objects and a positive patch test reaction to nickel. A detailed smoking history was obtained in a questionnaire. RESULTS: Contact allergy (adjusted odds ratio, 1.8; 95% CI, 1.2 to 2.9), nickel contact allergy (adjusted odds ratio, 2.7; 95% CI, 1.4 to 5.2), and allergic nickel contact dermatitis (adjusted odds ratio, 3.0; 95% CI, 1.5 to 6.2) were significantly associated with a smoking history of more than 15 pack-years. Moreover, these associations showed a significant dose-response relation, and they were independent of sex, age, and exposure to nickel, as reflected by a history of ear piercing. CONCLUSIONS: These data raise the hypothesis that smoking increases the risk of contact allergy. Further epidemiologic studies and investigations into the possible mechanisms are warranted.
[Smoking and long-term oxygen therapy. Indications and contraindications].
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Release of chemical permeation enhancers from drug-in-adhesive transdermal patches.
There is only limited knowledge of how chemical permeation enhancers release from transdermal drug delivery systems of the drug-in-adhesive type. In this study, the release of eight commonly known enhancers from eight types of polymer adhesives was evaluated using Franz diffusion cells. It was shown that all the enhancers released completely from the adhesives and followed a square root of time kinetic (Higuchi law). Using a statistical analysis it was shown that the release rate was more dependent on the type of enhancer than on the type of polymers. The mean release rates were in the range from 2.2 to 11.1%/ radical t for the slowest and fastest releasing enhancers, which correspond to a 50% release within 500 and 20 min, respectively. Furthermore, the release rates were inversely proportional to the cube root of the molal volumes of the enhancers and to their logarithmic partition coefficients between the polymer adhesive and the receptor fluid. It was found that the observed release rates were probably due to a high diffusion coefficient of the enhancers rather than due to an inhomogeneous embedment of the enhancers in the adhesives. The type of adhesive showed minor influence on the release rate, especially among the acrylic polymers no difference was seen. However, compared to the acrylic adhesives, the polyisobutylene adhesive showed slower release rates, while the silicone adhesive showed slightly faster release rates.
The association between contact allergy and hand eczema in 2 cross-sectional surveys 8 years apart.
Hand eczema is a recurrent chronic skin disease related to contact allergy and atopic dermatitis. When possible, efforts should be redoubled to eliminate provoking factors. Our objective was to assess changes in the prevalence of self-reported hand eczema and to evaluate the association between contact allergy and hand eczema among adult Danes before and after nickel exposure regulation in Denmark. In 1990 and 1998, random samples of 15-41-year-old persons were examined in 2 cross-sectional studies of the general population in Copenhagen, Denmark. The studies included questionnaires, patch and prick testing. From 1990 to 1998 the prevalence of a history of hand eczema increased significantly. This increase did not appear to be fully explained by changes in the prevalence of flexural eczema, prick test reactivity, patch test reactivity, and nickel allergy. In 1990, nickel allergy and allergic nickel contact dermatitis were significantly associated with a history of hand eczema among women. In 1998, these associations were not found. It can be concluded that, from 1990 to 1998, the prevalence of a history of hand eczema rose significantly. It was indicated that it might be possible to prevent the hand eczema related to nickel allergy by exposure regulation, public education or both.
Have oral contraceptives reduced the prevalence of acne? a population-based study of acne vulgaris, tobacco smoking and oral contraceptives.
BACKGROUND: The prevalence of acne among adolescents appears to vary geographically. This study was therefore undertaken to describe the prevalence rate of acne among Danish adolescents and to study the possible influence of oral contraceptives (OC) and tobacco smoking on disease prevalence and severity. Both have been suggested to influence acne and are therefore potential confounders in studies of acne prevalence. METHODS: A random sample of 186 15- to 22-year-old subjects participating in a population-based study of allergic diseases in Copenhagen County were also examined for acne. Questionnaire data on demographic variables, acne problems, smoking status and use of OC were recorded, and acne was graded according to the Leeds scale. RESULTS: The prevalence of clinical acne (Leeds score >1) was 40.7% for men and 23.8% for women (odds ratio, OR, acne vs. no acne: 0.46, 95% confidence interval, CI: 0.24-0.85). Acne was perceived as a personal problem by 37.6% of all subjects, and this was associated with clinical acne (OR: 5.5, 95% CI: 2.7-10.9). The use of OC was associated with a significantly lower prevalence of acne (OR: 0.32, 95% CI: 0.11-0.86), while the use of tobacco smoking was not significantly associated with acne (OR: 0.54, 95% CI: 0.17-1.78). CONCLUSION: In congruence with recent reports from other countries, the prevalence rate of acne among adolescents was found to be lower than previously described in older reports. In this population, the use of OC was associated with a lower prevalence of acne.
Application of confocal laser scanning microscopy in characterization of chemical enhancers in drug-in-adhesive transdermal patches.
The purpose of this study was to evaluate the application of confocal laser scanning microscopy (CLSM) in the examination of the embedment and the release characteristics of chemical permeation enhancers from transdermal drug delivery systems (TDDSs) of the "drug-in-adhesive" type. The enhancer lauric acid and a lauric acid fluorescing probe of the Bodipy type were incorporated into TDDSs consisting of an acrylic, a polyisobutylene, or a silicone polymer adhesive. Three-dimensional confocal images of the distribution were obtained before and during release into an aqueous medium. The images showed that the lauric acid fluorescing probe was homogeneously embedded in all the adhesives except for 1 polyisobutylene. The release profiles and release rate constants of the lauric acid fluorescing probe were consistent with data from a release study of lauric acid performed using conventional measurements of the released amounts. This indicated that lauric acid was distributed in a homogeneous manner. Furthermore, it was possible to illustrate the mechanics of the diffusion process inside the TDDS and compare these patterns with theoretically drawn profiles, based on Fick's law of diffusion. CLSM was demonstrated to be an excellent tool to study how enhancers are incorporated and diffuse into a TDDS.