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Biomedical subjects

G Ducombs

Publications and source records attributed to G Ducombs.

At least 37 records · Page 2Linked to original sources
PubMed1992

Contact sensitivity to flavourings and perfumes in atopic dermatitis.

16 children with atopic dermatitis and 4 nonatopics were skin tested with flavourings and perfumes. Immediate reactions to balsam of Peru and fragrance-mix were found in 9 atopics, and none among nonatopics. An irritant is more probable than an immunologic mechanism. Allergen solutions should probably be assayed at a lower concentration in atopic patients. This study points to a possible aggravating factor from perfumes and flavourings ingested, inhaled, or used as cosmetics.

Child↗
PubMed1990

Contact allergy to Bronopol.

A total of 8149 patients were patch tested with the preservative Bronopol in 7 European contact clinics. The majority of patients (6507) were investigated in London. Reactivity was low, with a total of 10 irritant (0.12%) and 38 allergic reactions (0.47%). In only 17 cases (0.21%) was the patch test reaction to Bronopol considered to be of current or past clinical relevance. Concomitant sensitization to formaldehyde was present in about 1/3 of patients. Based on these figures, the present sensitization rate to Bronopol in Europe seems to be quite low, which may be related to its less frequent use as a preservative in cosmetics and medicaments in comparison to parabens or isothiazolinones.

Adolescent↗
PubMed1990

European multicenter study of TRUE Test, Panel 2.

Panel 2 of the standardized, ready-to-apply patch test, the TRUE Test, has been evaluated on 808 patients with suspected contact dermatitis. The patients were tested with 11 different allergens and the negative control, and compared with corresponding allergens in pet. (or aq.) in Finn Chambers fixed with Scanpor. The TRUE Test, Panel 2 and the control were applied symmetrically on the upper back. Left/right application of the respective test varied at random. Most tests were removed after 48 h and evaluated after 72 or 96 h, according to generally accepted recommendations. There were positive test reactions to all 11 allergens tested in the patient group. The concordance of positive reactions (1+, 2+, 3+) was 63% between TRUE Test, Panel 2 and the control method; 17% of positive reactions occurred only with TRUE Test, Panel 2 and 20% only with the compared method. Approximately 75% of all positive test reactions were explained by the patients' present or past history. Irritant/questionable reactions occurred in the same frequency for the 2 methods. Such reactions were recorded in less than 1% of all patches applied. No late reactions were recorded.

Allergens↗
PubMed1990

Patch testing with the "sesquiterpene lactone mix": a marker for contact allergy to Compositae and other sesquiterpene-lactone-containing plants. A multicentre study of the EECDRG.

6278 patients were patch tested with a sesquiterpene lactone mix (SL-mix) in 10 European clinics. 4011 patients were tested only with 0.1% SL-mix, 63 (approximately 1.5%) of whom were positive, with 26 (41%) of these cases being considered clinically relevant. There were no cases of active sensitization, though 5 cases of irritation were reported. 22 irritant reactions and 22 cases of active sensitization occurred when testing also with 1% and 0.33% concentrations of SL-mix. SL-mix 0.1% pet. is shown to be an important patch test and many relevant sensitizations will be missed without routine screening with such a mix. Most patients with SL-mix sensitivity presented with hand and/or face dermatitis, apparent photodermatitis or more generalised eczema.

Dermatitis, Contact↗
PubMed1990

[Diagnosis of dermatitis due to plants].

Contact dermatitis from plants may occur by several mechanisms. It may arise as a result of simple irritation or by allergic mechanism; co-exposure to sunlight can evoke the phenomena of phototoxicity or photoallergy. Etiologic diagnosis require botanical, chemical and immunologic knowledges. Patch testing can be performed with pure allergens (primin, sesquiterpene lactones etc.), plant extracts (balsams, oleoresins etc.) or with the plant itself. The validity of patch test results is often difficult to determine: false positive reactions due to the presence of pesticides or herbicides, active sensitizations, cross-reactions.

Allergens↗
PubMed1988

European multicenter study of the TRUE Test.

A new, standardized, ready-to-apply patch test, the TRUE Test, has been evaluated on 698 consecutive patients with suspected contact dermatitis. The patients were tested with 12 different allergens. Simultaneously, the same 12 allergens in pet. (Trolab) were applied symmetrically to the opposite side of the upper back using the conventional Finn Chamber technique. There were positive test reactions to all 12 allergens tested in the patient group. The concordance of positive reactions between the TRUE Test and the Finn Chamber test was 67%; 13% of all positive reactions were recorded only for the TRUE Test and 20% only for the Finn Chamber method. The frequency of questionable and irritant reactions was of the same low order of magnitude for both test methods; such reactions were recorded in around 2% of all test patches.

Allergens↗
PubMed1988

[Multicenter survey related to the frequency of positive patch tests with mercury and thiomersal].

A multicentric study concerning the frequency of positive allergic patch test reactions to mercury and to thiomersal has been conducted in France and in Belgium among 2,000 adult patients submitted to routine patch testing. 73 (3.6 p. 100) patients had a positive patch test to mercury and 47 (2.3 p. 100) to thiomersal, 22 (1.1 p. 100) reacted positively to both mercurials. These high figures are most probably in relation with a broad use of mercurials in both countries, as antiseptics as well as preservative agents in topical drugs. They lead to a careful use of mercurials, which have to be avoided when they can be advantageously replaced by other antiseptics or preservative agents. As far as cosmetics are concerned, the use of mercurials (chemical nature and concentration) is restricted by a Recommendation of the European Council.

Adult↗
PubMed1988

[The oak processionary caterpillar (Thaumetopoea processiona L.) and man: urticating apparatus and mechanism of action].

The urticating apparatus of the oak processionary caterpillar was studied by electron microscopy at times when this species was exceptionally abundant in France. Proteins of urticating hairs were studied by electrophoresis on acrylamide gel and were compared with thaumetopoein, an urticating protein of the pine processionary caterpillar, using immunological techniques. A thaumetopoein-like protein was found to be present in oak processionary urticating hairs. This protein has a histamine-releasing effect in the guinea-pig. Contact dermatitis caused by the oak processionary caterpillar is described and compared to that produced by the pine processionary caterpillar.

Animals↗
PubMed1987

Contact dermatitis. A review.

In recent years, there has been a dramatic rise in our understanding of contact dermatitis. This paper is a review of our knowledge of the mechanisms involved in contact dermatitis and related phenomena, the investigation of these events and the emergence of significant new allergens during the last 5 years.

Allergens↗
PubMed1986

Thaumetopoein: an urticating protein from the hairs and integument of the pine processionary caterpillar (Thaumetopoea pityocampa Schiff., Lepidoptera, Thaumetopoeidae).

Hairs of the Thaumetopoea pityocampa caterpillar (Lepidoptera) cause a cutaneous reaction in man and animals. The irritating fraction extracted from hairs contains soluble proteins which were separated by various electrophoretic and immunoelectrophoretic techniques. Some of these proteins are present also in cuticle and haemolymph. One protein of 28,000 mol. wt is hair specific and caused a reaction in pig skin identical to that produced by hair extract. It is therefore an urticating protein which we have named thaumetopoein. This protein is formed of two subunits of molecular weights 13,000 and 15,000. It is present in large quantities in the glands producing urticating hairs.

Animals↗