Toxic effects of systemic retinoids on meibomian glands.

Systemic use of retinoids is common in the treatment of various dermatological disorders. Blepharitis and conjunctivitis have been reported in 20-45% of the patients following systemic treatment with 13-cis-retinoic acid. Our purpose was to study the histopathological changes in the eyelids caused by long-term systemic treatment of female New Zealand rabbits with isotretinoin (2 mg/kg) and etretinate (2 mg/kg).

The pituitary-thyroid axis effects on ocular and orbital tissues: a histological, histochemical, and morphometric study.

This work tests the notion that the effect of thyroid hormone on orbital and ocular tissues is mediated through its action on their lysosomal enzymes. Hyperthyroidism was produced in guinea pigs by thyroxin and TSH; hypothyroidism was induced by thiouracil. After treatment for 10 to 21 days, several ocular and orbital tissues were taken for histological, morphometrical, and histochemical examinations.

Reappraisal of the role of macrophages in the pathogenesis of atherosclerosis.

New Zealand rabbits were fed an atherogenic diet, 8 with and 8 without twice weekly intravenous injections of GdCl2. The injections caused a reduction in the phagocytic activity of the reticuloendothelial system by one fourth to one half. No significant differences were found between the two groups in the planimetric extent of atheromata in the aortae.

Effects of various drugs on denervation changes in rat muscles.

The effects of drugs, known to affect lysosomal enzyme activities on denervated gastrocnemius muscles of rats were studied. The drugs used were: amiodarone, chloroquine, cortisone, streptomycin and trypan blue. The parameters investigated included changes in fibrillations in electromyographs, morphometric evaluations of muscle atrophy and replacement, and light and electron microscopic analysis of morphological changes and of histochemical acid phosphatase activity.

An attempt to prevent or delay denervation changes in rat muscles.

A number of drugs which are known to affect lysosomes and their enzyme activities were used in an attempt to inhibit or delay the onset of denervation changes in rat muscles. The following parameters were used: the occurrence of fibrillations in electromyographs; diameters of muscle fibers; acid phosphatase activity; acetylcholinesterase activity and distribution in end plates. Differences between denervated and non-denervated limbs were evaluated and compared in the different treatment groups.