6278 patients were patch tested with a sesquiterpene lactone mix (SL-mix) in 10 European clinics. 4011 patients were tested only with 0.1% SL-mix, 63 (approximately 1.5%) of whom were positive, with 26 (41%) of these cases being considered clinically relevant. There were no cases of active sensitization, though 5 cases of irritation were reported. 22 irritant reactions and 22 cases of active sensitization occurred when testing also with 1% and 0.33% concentrations of SL-mix. SL-mix 0.1% pet. is shown to be an important patch test and many relevant sensitizations will be missed without routine screening with such a mix. Most patients with SL-mix sensitivity presented with hand and/or face dermatitis, apparent photodermatitis or more generalised eczema.

Murine models for the assessment of the contact sensitizing properties of chemicals rely on mouse ear swelling tests (Mest), which are not sensitive enough to detect weak sensitizers. The aim of the present study was to develop in mice an adjuvant-free Mest appropriate for in vivo detection of any type of sensitizer (weak to strong), and useful for in vitro assessment of contact sensitivity (CS). 3 haptens were tested: dinitrochlorobenzene (DNCB), para-phenylenediamine (pPD) and isoeugenol. We compared various protocols for induction of the CS reaction, differing by the site of induction, the number of applications and the concentrations of the 3 haptens. Comparison of the induction site for optimal CS reaction showed that, in Balb/c mice, the back was a better site of induction than the abdomen. Detection of the sensitizing properties of weak sensitizers (pPD, isoeugenol) was possible using an adjuvant-free protocol, provided that the induction phase comprised hapten applications on 3 consecutive days on the backs of animals. For DNCB, one application was sufficient to obtain optimal CS reaction. For all 3 haptens, a secondary response in vitro was obtained using semi-purified lymph node T cells from animals sensitized 5 days before with the optimized Mest. These results demonstrate that the Mest could be a useful experimental model for the study of all types of contact sensitizers.

Several examples of phosphonates with rigid geometries provide definite evidence for a Karplus-type variation of 31P-C-C-1H couplings in phosphonates. The coupling is maximum for a 0 (-18 Hz) and a 180" dihedral angle and minimum for a 90" angle vidence for the dihedral angle dependence of

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