Evaluation of 4-month-old girl who presented with congenital cataracts revealed heterochromia iridis, fundus hypopigmentation, residual white forelock and sensory neural hearing loss--findings consistent with Waardenburg syndrome type II. Bilateral peripheral iridectomies performed at lensectomy provided tissue for evaluation. Light microscopy revealed fewer melanocytes in the blue iris than in the brown. Electron microscopic examination showed a significant (p = 0.0001) reduction in melanosome size in the blue iris, and the nerve endings contained fewer vesicles. A defect in neural crest cell migration and melanin synthesis may be responsible for the heterochromia iridis seen in Waardenburg syndrome type II.

Purpose and Background: To measure azithromycin levels in rabbit lacrimal and Harder glands, conjunctiva and plasma after a single oral dose of 20 mg/kg. Drug levels in lacrimal gland tissue are significant in trachoma because the gland may be involved in the disease process and it is the source of tears by which the drug is carried to the external eye. Methods: Lacrimal and Harder glands, conjunctiva and plasma were collected from New Zealand white female rabbits at 24, 48, 72, 96 and 144 h following a single oral dose of azithromycin (20 mg/kg). Azithromycin levels in tissue and plasma were measured using high-performance liquid chromatography (HPLC) electrochemical detection. Results: Azithromycin levels peaked within the first 24 h in all tissues and plasma assayed. The highest concentration was in the lacrimal gland (6.2 µg/g, SD ± 0.8), followed by Harder gland (4.4 µg/g, SD ± 0.8), conjunctiva (0.9 µg/g, SD ± 0.5) and plasma (0.06 µg/g, SD ± 0.03). These concentrations reached their lowest measured levels at 120 and 144 h. Conclusion: Azithromycin levels measured throughout the 144 h after dosing were consistently above the minimum inhibitory range (MIC) for Chlamydia trachomatis (0.03–0.25 µg/ml) in the lacrimal glands, while the conjunctiva maintained a concentration above the MIC for 96 h and stayed within MIC levels for 144 h.