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Biomedical subjects

I S Foulds

Publications and source records attributed to I S Foulds.

At least 19 recordsLinked to original sources
PubMed1996

Identification of contact allergens in unmodified rosin using a combination of patch testing and analytical chemistry techniques.

In order to investigate the contact allergens in the unmodified colophony (rosin) used in routine patch testing, preparative chromatographic techniques were used to separate its components which were then patch tested on colophony-sensitive individuals. The chemical structure of the dermatologically active components was elucidated using mass spectrometry, nuclear magnetic resonance and infra-red techniques. The study shows that oxidized resin acids are stronger sensitizers than the resin acids themselves, the most potent contact allergen being 7-oxydehydroabietic acid (purity 92%). At naturally occurring concentrations (relative to abietic acid) all unoxidized resin acids were found to play an insignificant part, individually, in colophony dermatitis, except abietic acid (purity 99%), which was found to be a weak but important allergen. The commercial Trolab abietic acid preparation (unknown purity) was found to be dermatologically more active than purified abietic acid.

Abietanes↗
PubMed1995

Allergic potential of neutrals in unmodified colophony, and a method for their separation from resin acids.

An ion-exchange fractionation technique for the separation of total resin acid and neutral fractions of unmodified colophony is described. The allergic potential of these fractions was assessed by patch testing colophony-sensitive individuals, and this showed that both the neutral components and the resin acids play an important role in colophony sensitization. A greater frequency of positive reactions was obtained using the 60% colophony patch test preparation compared with the currently recommended 20% colophony preparation. Furthermore, some individuals were found to produce positive reactions to only the neutral components in colophony. We suggest that the use of a colophony patch test battery comprising resin acids, neutrals, oxidized resin acid and some colophony derivatives, will facilitate detection of colophony-sensitive individuals. Moreover, we consider that this will help to provide a better estimate of the prevalence of colophony dermatitis, which is currently underestimated.

Chemical Fractionation↗
PubMed1994

Colophony--uses, health effects, airborne measurement and analysis.

Colophony (rosin) is a widespread natural product obtained form species of the pine family Pinaceae. One of the most important uses of unmodified rosin is in electronic solder fluxes while the main areas of use of chemically modified rosin are paper sizing, adhesives, paints, varnishes, printing inks and plasticisers. Colophony is well recognized as a skin sensitizer and is also the third highest cause of occupational asthma. However, the specific allergens involved particularly in occupational asthma have not been comprehensively assessed or identified. This paper reviews method of colophony production, its uses and health effects and discusses the important issue of its chemical analysis and the choice of a suitable marker for monitoring colphony fume.

Air Pollutants, Occupational↗
PubMed1992

Fiberglass dermatitis from printed circuit boards.

Seven cases of fiberglass dermatitis among production operators in the electronics industry are reported. This was due to the repeated daily handling of printed circuit boards (PRCBs). The predominant complaint of the workers was itch of the lateral aspects of the fingers and finger webs. In six workers, unroofed vesicles, pinhead areas of postinflammatory hyperpigmentation, and excoriation marks were noted at these sites. Skin stripping of the affected sites confirmed the presence of fiberglass spicules in all cases. The glass fibers had diameters of 11-16 microns. Patch testing of six of the workers with the European Standard series of allergens revealed no relevant work-related contact sensitizers. Microscopic examination of the free edges and scrapings from the PRCBs showed glass fibers of similar fiber length and diameter to those found in the workers' skin. Fiberglass can be used as a reinforcement filling material in some types of PRCBs. Free edges of such PRCBs have easily detached fiberglass spicules. Workers in frequent contact with these PRCBs can have a fiberglass-induced irritant dermatitis. Preventive measures could include the use of PRCBs with less free fiberglass at its edges, vacuuming of the newly cut boards, use of dusting powder, protective devices and emollients, and improved personal hygiene of the workers.

Adult↗
PubMed1992

Allergic contact dermatitis from resin hardeners during the manufacture of thermosetting coating paints.

5 production operators from 2 factories manufacturing thermosetting coating paint developed work-related skin disorders within 12 months of the introduction of a new powdered paint product. All 5 workers were found to have allergic contact dermatitis from 2 epoxy resin hardeners, both of which were commercial preparations of triglycidyl isocyanurate (TGIC). 2 of the workers had concomitant sensitization to epoxy resin in the standard series and several of the epoxy resin preparations at the workplace. TGIC has been reported as a contact sensitizer both in persons producing the chemical and among end-users of TGIC-containing products. These 5 reported cases document allergic contact dermatitis from commercial TGIC among exposed workers during an intermediate process of powdered paint manufacture. The possibility of substituting this epoxy resin hardener with less sensitizing alternatives should be explored.

Adult↗
PubMed1991

Loss of lanolin patch-test positivity.

Thirty-seven patients who had shown a relevant positive patch-test response to lanolin within the previous 5 years were retested. Only 41% demonstrated persistence of the positive patch test to lanolin. Analysis according to age, sex, atopic status, interval between patch testings, strength of the original response and the number of concurrent reactions, were not associated with the persistence of the lanolin response.

Adult↗
PubMed1991

Basal-cell carcinoma complicating a port-wine stain.

A rare radio-resistant basal-cell carcinoma is described which presented as a recently enlarged non-ulcerated nodule on a port-wine stain. The literature on basal-cell carcinoma occurring on a port-wine stain is reviewed, and the aetiological significance of thorium-X, sun-exposure and vascular changes in the development of malignancy on this type of haemangioma is discussed.

Basal Cell Carcinoma↗