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Biomedical subjects

S M Wilkinson

Publications and source records attributed to S M Wilkinson.

At least 73 records · Page 4Linked to original sources
PubMed1998

Assessment of invasion frequencies of cultured HEp-2 cells by clinical isolates of Helicobacter pylori using an acridine orange assay.

AIMS: Recent studies suggest that Helicobacter pylori is an invasive enteropathogen. However, the efficiency with which this pathogen invades mammalian cells remains unknown. Therefore, this study was designed to investigate the invasion frequencies of HEp-2 cells by clinical strains of H pylori. METHODS: An acridine orange assay and cultured HEp-2 cell monolayers were used to determine the HEp-2 cell penetration frequencies of 17 clinical isolates and one American Type Culture Collection (ATCC) strain of H pylori, and single clinical strains of Yersinia enterocolitica, Shigella flexneri, and a non-invasive ATCC Escherichia coli strain. RESULTS: The acridine orange assay demonstrated that invasion frequencies of HEp-2 cells by all H pylori isolates were significant and, in most instances, exceeded those for the S flexneri strain and equalled those for the Y enterocolitica strain. The assay also showed that internalised H pylori organisms remained viable for at least six hours, the maximum time that bacteria and HEp-2 cells were co-incubated. CONCLUSIONS: These results may have important implications for treatment and prevention strategies for this gastric pathogen. Furthermore, the acridine orange assay may be useful for assessing, in vitro, the ability of conventional and newer antibiotics, alone or in combination, to kill intracellular H pylori organisms.

Acridine Orange↗
PubMed1997

An assessment of steroid hypersensitivity in asthma.

In dermatological practice, allergy to topical corticosteroids used to treat eczema is a recognized and common event. The typical presentation is of an eczema which fails to improve or deteriorates with treatment. Topical corticosteroids are also used to treat mucosal disease. This study assesses allergy to inhaled corticosteroids in asthmatics. In the patient group selected, there was no evidence of relevant corticosteroid allergy.

Administration, Inhalation↗
PubMed1997

Patch testing to detect corticosteroid allergy: is it adequate?

Whilst patch testing with corticosteroids in ethanol is more sensitive than either petrolatum or the cream formulation, the frequency of false-negative reactions is not known. We have compared patch testing with corticosteroid at 1% in ethanol with intradermal (i.d.) tests using 1 mg corticosteroid suspended in normal saline. Patch tests with tixocortol pivalate and budesonide detected all patients allergic to hydrocortisone and budesonide, respectively. For other corticosteroids, the use of ethanol as a vehicle resulted in both false-positive and false-negative reactions. In particular, patch tests with hydrocortisone-17-butyrate missed 30% of all positive reactions detected by i.d. testing. There may be a case for advising the avoidance of this steroid in all patients who are positive on patch testing to tixocortol pivalate and budesonide.

Anti-Inflammatory Agents↗
PubMed1996

Corticosteroid contact hypersensitivity: what vehicle and concentration?

The correct concentration and vehicle for patch testing with corticosteroids is in many instances not known. The results of this study suggest that 1% in ethanol should be the initial choice, unless it can be shown that petrolatum as a vehicle is as sensitive (tixocortol pivalate and budesonide). We could find no evidence for the anti-inflammatory effects of corticosteroids inhibiting the patch test at higher concentrations. Using ethanol as the vehicle resulted in reactions developing at earlier time points than with petrolatum.

Administration, Topical↗
PubMed1996

Allergic contact dermatitis from latex rubber.

Previously we have found occasional patients with delayed hypersensitivity to latex (in rubber gloves) in the absence of allergy to any chemicals in the rubber chemical screen. There are many reports of contact urticaria to latex and isolated reports of delayed hypersensitivity to latex, usually in the presence of contact urticaria. To establish if latex ruber is a more common cause of delayed hypersensitivity than is currently recognized, we patch tested all patients attending our contact dermatitis clinic, over a 6-month period, with latex. Of 822 patients, 16 (1.9%) demonstrated positive cutaneous reactions to latex. Six exhibited contact urticaria to latex, five contact urticaria and allergic contact dermatitis, and five allergic contact dermatitis alone. Of the five with delayed hypersensitivity to latex in the absence of contact urticaria, only one was atopic and the sensitivity was thought to be relevant or possibly relevant in four. Of our patients, 1.2% exhibited positive patch-test reactions to latex. Patch testing with latex should be considered where contact dermatitis to a latex rubber-containing product is suspected, e.g. gloves and footwear.

Adolescent↗
PubMed1996

Corticosteroid usage and binding to arginine: determinants of corticosteroid hypersensitivity.

Hypersensitivity to topical corticosteroids is a common cause of allergic contact dermatitis. The development of contact allergy is dependent on individual susceptibility, exposure to the potential allergen and the ability to penetrate the epidermis and react with epidermal protein. We looked at corticosteroid binding to arginine and relative usage of corticosteroids to see if these variables explain the number of allergic reactions seen to these structurally similar chemicals. A linear relationship was found between a measure of corticosteroid binding to arginine, the log of relative corticosteroid usage and the log of the relative number of corticosteroid allergies. Using multiple regression this association was significant (P = 0.01). Statistically, these two variables accounted for 73% of the variation in the results. Our results showed that the number of corticosteroid allergic reactions was dependent on usage and the intrinsic ability of the corticosteroid to degrade and bind to arginine. While total corticosteroid usage is unlikely to change, the prescription of individual corticosteroids with a reduced potential to degrade and bind to protein, but with equal efficacy, might reduce the overall prevalence of corticosteroid hypersensitivity.

Analysis of Variance↗
PubMed1995

Reactions to other corticosteroids in patients with allergic contact dermatitis from hydrocortisone.

It has been proposed that corticosteroid cross-reactions occur more frequently within structurally well-defined groups. To test this hypothesis we have compared the patch-test reactions to other corticosteroids in 96 patients allergic to hydrocortisone. We found that our data did not agree with the previously proposed classification. The presence of a substitution at the C6 or C9 position was the most important factor in determining whether a patient would be allergic to another corticosteroid. This information should facilitate the choice of an alternative corticosteroid in patients allergic to hydrocortisone, if facilities for patch testing to other corticosteroids are not available.

Cross Reactions↗