["Morphologic changes of the vascular endothelium are common in patients with systemic sclerosis and Raynaud's phenomenon. The aim of this study was to evaluate the endothelium-dependent vasodilatation and endothelium-independent vasodilatation and to examine the effects of short-term estrogen administration on vascular responses in these patients.", "The study included 12 female patients with systemic sclerosis and Raynaud's phenomenon (aged 49+/-14 years) and 12 age- and sex-matched healthy control subjects. With the use of high-resolution ultrasound imaging, brachial artery diameter was measured at rest, during reactive hyperemia (endothelium-dependent response), and after administration of sublingual nitroglycerin (endothelium-independent dilatation). Intima-media thickness of the common carotid artery was also measured. Baseline diameter was similar in patients and control subjects; intima-media thickness was significantly higher in patients (0.83+/-0.3 vs 0.46+/-0.2 mm, P= .002) than in control subjects. Flow-mediated dilatation was reduced in patients (3.6%+/-7% vs 11.9%+/- 4.6%, P = .003); endothelium-independent dilatation also was reduced in patients with Raynaud's phenomenon (14%+/-7% vs 23%+/-6%, P= .003). Vascular responses in 10 patients were examined 15 minutes after administration of conjugated estrogens (25 mg intravenously); there was a significant increase of endothelium-dependent dilatation after estrogen administration (1.7%+/-4% to 6.3%+/-4%, P= .01), whereas endothelium-independent dilatation did not change (13.4%+/-8% to 15.5%+/-7%, not significant)."] Does short-term estrogen administration improve abnormal endothelial function in women with systemic sclerosis and Raynaud 's phenomenon?