Over the past few years, beta-carotene has progressively gained ground as a drug chosen in the treatment of oral leukoplakias, thus making it possible to reduce the use of 13-cis-retinoic acid, which was shown by many studies to be highly toxic while beta-carotene has proved to have no significant side effects and hence to be much more suitable in oral premalignancy. In 1989, a phase II study of patients showing oral leukoplakias and treated with beta-carotene (90 mg/day) was begun. A total of 23 patients (aged between 17 and 85) were included in the study and 18 (8 male and 10 female) were evaluated. Eight patients (44.4%) had objective responses (6 complete, 2 partial). Four CR and a PR appeared unexpectedly within 2-7 months after the end of the therapy. The lesions were macroscopically and histologically examined at entry; in the evaluated patients, two types of alterations were found: atypical hyperplasia (16 patients) and dysplasia (2 patients). No signs of significant toxicity were detected; only in 1 patient treatment had to be interrupted for 1 week. The results of this study show the fair efficacy of beta-carotene against oral leukoplakias, but further confirmations through controlled clinical studies are needed.

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A pair of time projection chambers has been tested in an 85GeV/cπ− beam. The chambers were placed inside the magnetic field of the Ω′ spectrometer at CERN. A description of the device and the associated electronics is given. Results obtained on track and vertex reconstruction accuracy are presented

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