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A proposed mathematical formula devised as a solution to the electrical power distribution problem changes the original nonlinear model into its equivalent and completely linear model. The generalized Benders decomposition technique and the ZOOM/XMP software reduces the size of the problem such that the approach is able to accommodate the problem. However, further study on an alternative procedure is recommeneded.

Fifty-six patients with presumed ocular histoplasmosis syndrome who exhibited a disciform macular detachment or macular scar in one fundus and one or more inactive atrophic lesions within the high-risk area of the second eye were seen at the Retina Service of Maisonneuve-Rosemont Hospital, Montreal, between 1972 and 1984. All 56 were followed for at least 10 months. Of the 56, 28 had received prophylactic argon laser photocoagulation of the inactive chorioretinal lesions. The rate of activation of the lesions was similar in the treated and untreated groups (10/28 over a mean follow-up period of 44.2 months and 11/28 over a mean period of 43.2 months respectively). In the untreated group there was an increased risk of activation with a higher number of lesions (t = 2.386). In both groups the risk of activation increased with the proximity of the lesions to the centre of the fovea (chi 2 = 29.97). Of the 10 treated eyes that showed activation, 4 did so within 1 month, which suggests that prophylactic photocoagulation may not be without risk of complications.

The increase in the number of newly diagnosed cases of prolactinomas seems to coincide with the use of oral contraceptives during the past two decades. The following retrospective case-control study was undertaken in an attempt to disprove a null hypothesis of relationship between oral contraceptive use and prolactinomas. Each of 70 patients operated upon for removal of a prolactinoma was closely matched for age, gravidity, and year of final diagnosis with one patient in each of three control groups. The control groups selected were constituted, respectively, of patients with secondary amenorrhea and normal prolactin levels, patients with normal ovulatory cycles consulting for infertility, and subjects without medical or gynecologic problems. No statistically significative differences were found in the exposure rates to oral contraceptives among four groups. This study thus failed to reveal a significant association between prolactinomas and oral contraceptives but, given the sample size, a relative risk lower than 3.32 cannot be demonstrated or disproved.