RESUMO
PURPOSE: To report a case exhibiting drastic regression of a conjunctival nevus in a child. CASE REPORT: Spontaneous regression of conjunctival nevus is uncommon. We report the case of a nine-year-old Caucasian boy presenting a conjunctival-pigmented lesion situated at the plica semilunaris that underwent a significant reduction in size and color over a period of 15 months. CONCLUSION: Conjunctival nevus in children is common but regression is rare, especially at the plica. This information could form an important part of the consent process when choosing between observation and surgical excision in the management of a small conjunctival lesion with no suspicious clinical features; since the latter invasive treatment involves risks such as infection, scarring and the possible risk of general anesthesia in children.
RESUMO
Ascorbate blocks agonist-induced, endothelium-derived hyperpolarizing factor (EDHF)-mediated vasodilatation in the bovine perfused ciliary artery and this is associated with a rise in perfusion pressure. We now report the origins of this ascorbate-induced rise in perfusion pressure. In segments of ciliary artery perfused at 2.5 ml/min, the addition of ascorbate (10-150 microM) enhanced U46619-induced perfusion pressure. Ascorbate produced no enhancement in the absence of U46619, suggesting that its effects resulted not from a constrictor action but through removal of a tonic vasodilator influence. Experiments revealed the endothelial source of this vasodilator influence, and EDHF, but not nitric oxide or prostanoids, appeared to be involved. The ascorbate-induced enhancement of vasoconstrictor tone was not seen in a static myograph or in segments perfused at low rates of flow, but was seen at flow rates of 2.5 ml(-1) and above. We conclude that ascorbate augments vasoconstrictor tone through inhibition of flow-induced EDHF activity.
