Methyldibromoglutaronitrile is an important contact allergen in The Netherlands

From 15 May to 15 December 1994, 2943 patients suspected of having contact dermatitis (1955 women, 988 men) were patch tested with methyldibromoglutaronitrile 0.3%, 0.1% and 0.05% pet. 119 patients (4.0%; women 4.1%, men 3.8%) proved to be allergic. 71% of the reactions were considered to be relevant. In 2/3 of the patients, causative products were cosmetics, in 1/3 moistened toilet tissues. Testing with methyldibromoglutaronitrile at lower concentrations (0.05% and 0.1%) and with commercial allergens (Euxyl K 400 and methyldibromoglutaronitrile, both containing methyldibromoglutaronitrile 0.1%), resulted in a number of false-negative reactions. All preservatives in the European standard series had lower scores than the 4% positive reactions to methyldibromoglutaronitrile (formaldehyde 2.0%, MCI/MI (Kathon CG) 3.2%, parabens 1.0%, quaternium-15 1.3%). It is concluded that methyldibromoglutaronitrile (present in the commercial preservative Euxyl K 400) is an important contact allergen in the Netherlands in cosmetics and moistened toilet tissues. It should be added to cosmetics series and to proctological series. The optimal test concentration is unknow, but may be 0.3% pet. The concentration of 0.1% methyldibromoglutaronitrile in the currently available commercial allergens appears to be too low, resulting in a number of false-negative reactions.

Digital photoplethysmography and light reflection rheography. A clinical comparison

BACKGROUND

Light reflection rheography (LRR) is appropriate for the global assessment of calf-pump insufficiency regardless of whether it is caused by varicosity, the post-phlebitic syndrome, or deep venous thrombosis. The instrument has been increasingly used by many phlebologists. Digital photoplethysmography (D-PPG) is a further development of this well-established LRR. With this D-PPG instrument it is possible, in contrast to LRR, to calibrate the reflected light.

OBJECTIVE AND METHODS

To compare the venous refilling times of both the LRR and the D-PPG when measured at the same time on the same leg. We also evaluated the practical use of both instruments. In total we performed 152 simultaneous measurements with both instruments.

RESULTS

We found a statistically significant correlation when we compared the venous refilling time of both LRR and D-PPG (r = .664; P < .001). The observed agreement between both instruments for detecting a disturbed venous refilling time (< or = 25 seconds) is 92%.

CONCLUSION

Both instruments seems to correlate as has been shown in this and other studies. The D-PPG has the advantage of being more handy. Furthermore the reflected light is calibrated, which enables to compare intra- and interindividual measurements.