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Biomedical subjects

S Fregert

Publications and source records attributed to S Fregert.

At least 37 records · Page 2Linked to original sources
PubMed1978

Simple methods for demonstration of epoxy resins of bisphenol A type.

Low molecular weight oligomers of epoxy resins of bisphenol A type are common sensitizers. For demonstrating the presence of sensitizing oligomers of these resins, two simple methods are described. The first one, a colour reaction, demonstrates the presence of the bisphenol A skeleton. If this test is positive, thin-layer chromatography is carried out to demonstrate the presence of low molecular weight oligomers of epoxy resins. Some practical applications are reported.

Chromatography, Thin Layer↗
PubMed1978

Triclocarban: evaluation of contact dermatitis potential in man.

Triclocarban was subjected to a profiling of its dermatitis producing potential including irritancy (21-day cumulative irritancy potential and application to 213 normal controls), phototoxicity (method of Marzulli), predictive contact sensitization (modified Draize method), predictive phototesting and battery screening in 2200 dermatitis patients, in an effort to define its relative dermatitis potential. The allergic contact dermatitis potential of triclocarban following bar soap use appears minimal.

Carbanilides↗
PubMed1978

Molecular weights of haptens.

Most haptens have a molecular weight below 400. Oligomers with increasing molecular weight have a decreasing sensitizing capacity. This is of both practical and theoretical interest.

Cell Membrane Permeability↗
PubMed1978

Sensitization capacity of epoxy resin oligomers in the guinea pig.

Low molecular weight oligomers of an epoxy resin of bisphenol A diglycidyl ether type were isolated by gel permeation chromatography. The sensitizing capacity of these oligomers was assessed with the "guinea pig maximization test". The oligomer with the molecular weight of 340 sensitized 80% to 100% of the animals, but produced no cross reactions to the other oligomers. The MW 624 oligomer sensitized 56-60% of the animals and 30% of these showed cross reactions to the MW 340 oligomer. The MW 908 and MW 1192 oligomers elicited no reactions. It was shown that sensitization with epoxy resin mixtures of high average molecular weight depends mainly on the content of the MW 340 oligomer.

Administration, Topical↗
PubMed1977

Patch testing with low molecular oligomers of epoxy resins in humans.

Thirty-four patients sensitive to epoxy resin were patch tested with oligomers of epoxy resin. All reacted when tested with MW 340 oligomer. Twenty-three were tested with MW 624 and MW 908 oligomers and seven with MW 1192 oligomer; none reacted. Eight patients tested with commercial mixtures of epoxy resins with an average MW 1280 and MW 1850 reacted to these resin mixtures which contained the MW 340 oligomer. The MW 340 oligomer seems to be the main ingredient responsible for contact allergy to epoxy resins in humans.

Allergens↗
PubMed1977

Allergenicity of epoxy resins in the guinea pig.

The sensitizing capacity of epoxy resins of diglycidylether-Bisphenol A type was investigated using the "guinea pig maximization test". One isolated resin had a molecular weight (MW) of 340, which is the lowest among this type of epoxy resin. The other resins were mixtures with different MWs. Their distribution is not known, but only their average MW. The low molecular weight resin sensitized all of the animals and can be classified as an extreme allergen. The sensitizing capacity decreased in inverse proportion to the increase in the average MW of the resin mixtures. The cross-testing also indicated that the resin mixtures with higher average MW contained enough of the low MW resin (MW 340) to render this resin a sensitizer. Bisphenol A did not sensitize the animals at all but epichlorhydrin sensitized 60%. It is evident that in order to formulate hypoallergenic epoxy resins it will be necessary to achieve sensitization of animals with isolated resins of varying molecular weight.

Allergens↗
PubMed1975

Occupational dermatitis in a 10-year material.

This study included 1,752 patients considered to have occupational dermatoses. The most common diagnosis was contact dermatitis. The dermatitis was of an allergic type in three-quarters of men and in half of women. One-fifth of the women with irritant contact dermatitis had an atopic history. Contact dermatitis was localized on the hands in 94% of women and in 84% of men. The most common allergens in men were chromium, rubber and plastic, and in women nickel, rubber and chromium. Chromium allergy occurred in four-fifths of the men in the building, metal and tanning industries. In one-fifth of the women, nickel allergy developed in cleaning work. Rubber allergy developed in the rubber industry in one-fifth of the cases. Half of the women with contact dermatitis were engaged in either nursing or cleaning work. A follow-up 2-3 years after treatment of 555 patients with contact dermatitis was completed by means of questionnaires. The eczema was healed in one-quarter of the patients, one-half had periodic symptoms, and one-quarter had permanent symptoms. The prognosis was the same for those who changed their work or stopped working as it was for those who continued their eczema-inducing work.

Adult↗