Multicentre patch testing with compositae mix by the Swedish Contact Dermatitis Research Group

Sesquiterpene lactone mix detects contact allergy to these compounds present in the plant family Asteraceae. This marker is present in many baseline series. An additional marker is Compositae mix, which is not present in many baseline series. To investigate whether this allergen should be inserted into the Swedish baseline series, six dermatology centres representing the Swedish Contact Dermatitis Research Group included Compositae mix into their baseline series for 1.5 years. Of 2818 patients tested, 31 (1.1%) reacted to Compositae mix and 26 (0.9%) to Sesquiterpene lactone mix. Active sensitization to Compositae mix was noted in two cases. Only 0.4% of Asteraceae contact allergy cases would have been missed if Compositae mix had not been tested, a frequency too low to merit its inclusion in the baseline series. Due to obvious geographical differences in frequency in frequency of simultaneous allergic reactions to Compositae mix and Sesquiterpene lactone mix, the question as to whether specific baseline series (including Compositae mix or not as a "tail" substance) should be used in the different centres must be addressed. Another option could be to remove Sesquiterpene lactone mix from the baseline series and substitute it with Compositae mix.

Multicentre patch testing with compositae mix by the Swedish Contact Dermatitis Research Group

Sesquiterpene lactone mix detects contact allergy to these compounds present in the plant family Asteraceae. This marker is present in many baseline series. An additional marker is Compositae mix, which is not present in many baseline series. To investigate whether this allergen should be inserted into the Swedish baseline series, six dermatology centres representing the Swedish Contact Dermatitis Research Group included Compositae mix into their baseline series for 1.5 years. Of 2818 patients tested, 31 (1.1%) reacted to Compositae mix and 26 (0.9%) to Sesquiterpene lactone mix. Active sensitization to Compositae mix was noted in two cases. Only 0.4% of Asteraceae contact allergy cases would have been missed if Compositae mix had not been tested, a frequency too low to merit its inclusion in the baseline series. Due to obvious geographical differences in frequency in frequency of simultaneous allergic reactions to Compositae mix and Sesquiterpene lactone mix, the question as to whether specific baseline series (including Compositae mix or not as a "tail" substance) should be used in the different centres must be addressed. Another option could be to remove Sesquiterpene lactone mix from the baseline series and substitute it with Compositae mix.

A comparison between Monte Carlo-calculated and -measured total efficiencies and energy resolution for large plastic scintillators used in whole-body counting

The measured total efficiency for several source positions has been determined for a large, plastic scintillation detector (NE 102A, 91.5 × 76.0 × 24.5 cm(3)) used for whole-body counting gamma spectrometry. The results have been compared with Monte Carlo-calculated total efficiencies; the code used was MCNPX 2.60. For (137)Cs, there was a good agreement between the measured and calculated total efficiencies. MXNPX was also used to calculate the electron light yield for (137)Cs; for the detector material NE 102A, Birks' constant kB was found to be 9.6 mg cm(-2) MeV(-1). The effect of light losses on spectrum resolution has been investigated for (65)Zn.

Correlation between stated and measured concentrations of acrylate and methacrylate allergens in patch-test preparations

BACKGROUND

Contact allergy to acrylates and methacrylates is not uncommon. The allergy is confirmed by patch-testing patients with commercial patch-test preparations.

OBJECTIVE

To investigate acrylate and methacrylate allergens used for patch testing in nine different dermatology departments from Europe, America, Asia, and Australia.

METHODS

The acrylate and methacrylate (methyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, ethylene glycol dimethacrylate, and triethylene glycol diacrylate) allergen samples were analyzed with high-performance liquid chromatography to measure the allergen content.

RESULTS

Variation in measured versus stated concentrations was seen in these samples. The ratio of measured to stated concentrations ranged from 0.11 to 1.1. Only 22 (63%) of 35 samples were within the arbitrary acceptable limits of 80 to 120% of the stated concentrations.

CONCLUSION

The results may have implications for individual diagnosis and prevention and when test results from various centers are compared.

Targeted resequencing of candidate genes using selector probes

Targeted genome enrichment is a powerful tool for making use of the massive throughput of novel DNA-sequencing instruments. We herein present a simple and scalable protocol for multiplex amplification of target regions based on the Selector technique. The updated version exhibits improved coverage and compatibility with next-generation-sequencing (NGS) library-construction procedures for shotgun sequencing with NGS platforms. To demonstrate the performance of the technique, all 501 exons from 28 genes frequently involved in cancer were enriched for and sequenced in specimens derived from cell lines and tumor biopsies. DNA from both fresh frozen and formalin-fixed paraffin-embedded biopsies were analyzed and 94% specificity and 98% coverage of the targeted region was achieved. Reproducibility between replicates was high (R² = 0, 98) and readily enabled detection of copy-number variations. The procedure can be carried out in <24 h and does not require any dedicated instrumentation.

Routine diagnostic patch-testing with formaldehyde 2.0% (0.6 mg/cm2) may be an advantage compared to 1.0%

Our clinical experience has suggested that the presently recommended patch-test concentration (1.0%) for formaldehyde in the baseline series might be too low. Therefore, consecutively patch-tested dermatitis patients were tested simultaneously with formaldehyde 1.0% and 2.0% (w/v) in aqua. Formaldehyde 1.0% and 2.0% were applied with a micro-pipette (15 microl) to filter paper discs in Finn Chambers (0.30 mg/cm(2) and 0.60 mg/cm(2), respectively). A total of 1397 patients with dermatitis were patch-tested. In all, 68 (4.9%) patients reacted positively to formaldehyde; 37 reacted only to 2.0%, 29 reacted to both concentrations, and 2 reacted only to 1.0%. Significantly more patients were thus diagnosed with contact allergy to formaldehyde 2.0% compared with 1.0% (p < 0.001). We detected 0.1%, 0.4%, and 29.6% irritant reactions to 1.0%, 2.0%, and 3.0% formaldehyde, respectively. We conclude that, with an optimized patch-test technique, doubling the dose per area detects significantly more contact allergies to formaldehyde, but an even higher test concentration causes too many irritant reactions to be usable.

Patch testing with a textile dye mix and its constituents in a baseline series

BACKGROUND

Among the textile dyes, disperse dyes are common sensitizers.

OBJECTIVE

To investigate whether patch testing with a textile dye mix consisting of eight disperse dyes would be equivalent to testing with the separate ingredients of the mix at the concentrations used in the mix.

METHODS

Researchers tested 1,780 consecutive patients with a mix consisting of Disperse Blue 35, Disperse Yellow 3, Disperse Orange 1, Disperse Orange 31 (mislabeled as Disperse Orange 3), Disperse Red 1 and 17, all at 0.5%, and Disperse Blue 106 and 124, both at 0.1%, and with the ingredients at these concentrations. Testing with the labeled dyes at 1.0% was done on 500 of the patients and additionally on the remaining patients who reacted positively to the mix, any of the ingredients, p-phenylenediamine, or black rubber mix.

RESULTS

Thirty-five patients (2%) reacted to the mix, and 34 patients were allergic to at least one ingredient tested at the lower concentration.

CONCLUSION

The textile dye mix was as good a detector of contact allergy to the disperse dyes as was testing with any combination of the ingredients at the concentration in the mix. Increasing the concentration of the ingredients of the textile dye mix might increase the sensitivity of the mix.

Occupational allergic contact dermatitis from epoxy resin in a golf club repairman

A golfer presented with facial and hand eczema. He had exacerbations of his hand eczema prior to golf tournaments. Being an authorized golf club repairman, he had been working with a two-part glue containing an epoxy resin (ER) based on diglycidyl ether of bisphenol A (DGEBA) and the hardener diethylenetriamine (DETA) for approximately 4 years before he developed any skin problems. He was patch-tested with the standard, which contains an ER based on DGEBA (DGEBA-R), epoxy (containing DETA), and rubber glove series and had positive reactions to DGEBA-R only. Other work materials (a latex glove, a golf glove made of leather, and part of the handle of his own golf club "as is" and in a methyl tert-butyl ether extract) were tested, with negative results. Allergic contact dermatitis from ER affects the skin by direct contact; the dermatitis is usually localized to the hands and forearms. If the face and eyelids are involved, the dermatitis may be due to exposure to airborne hardeners or reactive diluents, exposure to airborne dust from residual monomers, or ectopic allergic reactions. Our repairman had sandpapered an old glued surface, which may have led to possible airborne dust formation, thus explaining the facial eczema. Therefore, a worker with contact allergy to ER may continue working provided the skin is protected from contamination.