[Clinical aspects and etiology of erythroderma: an analysis of 64 cases]. / Klinik und Atiologie der Erythrodermie: Eine Analyse von 64 Fällen.

The difficulty of exfoliative dermatitis lies in the finding of underlying causes. In the present study the profile of 64 patients with erythroderma diagnosed between 1.1.1990 and 31.12.1999 were analysed. Clinical, histological and laboratory findings and their relationship to the aetiology were investigated. A masculine:feminine ratio of 2.6:1 was found. Among these patients the most common causative factors were pre-existing dermatoses (58%) and drugs (16%). In about eleven percent of the patients exfoliative dermatitis was associated with malignancy. Six out of seven malignancies were found in males, five of them suffering from pre-existing dermatosis. In 16 percent of the patients no aetiology of erythroderma could be found. No laboratory or clinical findings were indicative for an underlying malignant condition. Since we demonstrated underlying neoplastic disorders in seven (11%) of the cases, five of them also suffering from pre-existing dermatosis, we consider it absolutely necessary to screen for such diseases in the presence of the diagnosis exfoliative dermatitis.

Characterization procedure for ion-selective electrode assays of magnesium activity in aqueous solutions of physiological composition.

A magnesium ion-selective liquid membrane electrode based on a synthetic neutral carrier is presented. The selectivity for Mg2+ over Na+, K+, and H+ is sufficient for assays in the physiological range, but a chemometric correction of approximately 10% is still necessary for the Ca2+ interference. We optimized the membrane composition especially with respect to selectivity and accuracy by performing a new characterization procedure in which we simulated the variety of blood serum samples with 10 aqueous solutions. After a three-point calibration, these solutions were measured alternately with the middlerange calibrator for 3 min. The magnesium activity was evaluated after correcting for the calcium interference according to the Nikolsky equation. The selectivity coefficient, KpotMgCa, was itself fitted to give the minimum deviations from the assigned magnesium activities. Electrodes with an optimized membrane composition show an average deviation from theoretical activity values of about 1.6% with logKpotMgCa = -0.8.