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Clinical observations and experimental data suggest that sex hormones influence the develop ment of systemic lupus erythematosus (SLE). An imbalance between androgen and estrogen plasma levels may suggest an abnormality in the aromatase activity involved in estradiol syn thesis. Aromatase activity in skin and subcutaneous tissue and plasma sex-hormone levels (testosterone, androstenedione, estrone, estradiol, dehydrosterone sulfate, cortisol) were measured in 15 SLE patients (nine female, six male) who had never received corticosteroid treatment and in eight (four female, four male) healthy control subjects. There was a tendency toward an increase in aromatase activity in SLE patients when compared to control subjects. Among SLE patients the aromatase activity varied inversely with disease activity. Patients with SLE had decreased androgen and increased estrogen levels. Aromatase activity in SLE patients had significant direct correlation with estrogen levels. These data suggest that abnormal regulation of aromatase activity may partially explain the abnormalities of estrogen synthesis in SLE.

Why spend a lot of money on simplified training simulators modelling the power system, when the real system with no simplifications can be used for operator training? Procuring a simulator for training of operating personnel is often too expensive. This holds true especially for a small power system with limited resources. Nevertheless training is very important to ensure a proper quality of supply by reducing brown-outs and black-outs. In the ELKRAFT power pool the operator training is done by introducing planned alert states during daily operation, and a very realistic situation is thereby achieved. As it often happens during disturbances, unforeseen and unexpected situations are likely to occur. The achievement of a general understanding of the need for everybody doing, what is expected, is an additional benefit compared with the use of a training simulator. The cost of a training programme of this type is estimated as USD 10-15,000 each time, which is very reasonable considering that the training is done in the actual control room instead of in simplified training rooms. As a benefit, additionally to the training of the control centre personnel, the whole power system (power stations, grid, and personnel) is also tested and trained.