Ultrastructural analysis of the retinoid-induced reversal of epithelial hyperplasia and metaplasia.

The 7, 12-dimethylbenzanthracene-induced skin papilloma of the mouse and the 3-methylcholanthrene-induced hyperplasia and metaplasia in prostate organ cultures were studied by electron microscopy. The two types of tissue both showed a reversal of hyperplasia and metaplasia when treated with retinoids (= vitamin A and analogs). This reversal was reached by means that are quite characteristic for a given type of tissue.

Retinoids and cancer.

The early and recent investigations in the field of retinoids and cancer are reviewed. The retinoids, including natural vitamin A compounds and their synthetic analogs, present a new class of substances exerting a prophylactic and a therapeutic effect both in certain experimental tumor models and in certain clinical conditions of preneoplastic and neoplastic lesions. Because of a particular physiological mechanism of action, the retinoids offer a new approach to the cancer problem, which is different from those of surgery, X-ray therapy, conventional chemotherapy, and immunotherapy.

Retinoids, a new class of compounds with prophylactic and therapeutic activities in oncology and dermatology.

A review of recent investigations in the retinoid field is presented. Retinoic acid exerts a prophylactic and a therapeutic effect on chemically induced benign and malignant epithelial tumors in mice. In clinical studies positive therapeutic results have been obtained in patients with preneoplastic and neoplastic epithelial lesions.

Dihydroretinoic acids and their derivatives. Synthesis and biological activity.

The syntheses of the ring and four side-chain dihydroretinoic acids and/or their esters, 3-7, are described. The syntheses of several other retinoids containing a substituted aromatic ring are also included. The biological activity of the compounds was evaluated in vivo in a chemically induced mouse skin papilloma test and in vitro in two vitamin A deficient assays.

[Treatment of psoriasis with an orally administered effective new vitamin A acid derivative. Preliminary report].

The retinoic acid derivative Ro 10-9359 has been tested in 24 patients with psoriasis. In all patients the therapeutic activity was good to excellent. The symptoms of the hypervitaminosis A syndrome were slight to marked.

Vitamin A acid in benign and malignant epithelial tumours of the skin.

Vitamin A acid has a prophylactic and a therapeutic effect on chemically induced benign and malignant epithelial tumours in mice. Vitamin A acid, given orally, leads to a regression of established skin papillomas. Skin carcinomas too are influenced to a certain degree.

Therapy of epithelial tumors with an aromatic retinoic acid analog.

The properties of a new aromatic retinoic acid analog are described. The compound: all-trans-N-ethyl-9-(4-methoxy-2,3,6-trimethylphenyl)-3,7-dimethyl-2,4,6,8-nonatetraenamide = Ro 11-1430, exerts a therapeutic influence on chemically induced papillomas and carcinomas of the skin of mice. It leads to a marked regression of chemically induced epithelial tumors but does not inhibit the growth of transplantable tumors.