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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: UNLABELLED. Meshes: Arginine, Blood Flow Velocity, Cold Temperature, Coronary Angiography, Coronary Artery Disease, Coronary Vessels, Deferoxamine, Diabetes Mellitus, Type 2, Endothelium, Vascular, Female, Hemodynamics, Humans, Male, Middle Aged, Nitric Oxide, Vasoconstriction, Vasodilation, Vasodilator Agents.
user
Is [ Response of the coronary arteries to cold test and flow velocity increase improved by deferoxamine but not by L-arginine in diabetic patients ]? Context: Acetylcholine produces coronary artery (CA) constriction in diabetic patients suggesting an impairment of endothelium-dependent dilation. To examine the mechanism of this abnormal response. 2 physiological tests, i.e. cold pressor test (CPT) and coronary flow-increase induced by 10 mg papaverine (PAP) injection in the distal left anterior descending CA (dLAD), were performed before (1) and after (2) either i.v. L-arginine (L-arg, 625 mg/min x 10 min) or i.v. desferrioxamine (DFX, 50 mg/min x 10 min) in 15 normotensive nonsmoker diabetic patients with angiographically normal CA and normal cholesterol. Dimensions of the proximal LAD (pLAD) were measured by quantitative angiography. [table: see text] Before administration of L-arg or DFX, CPT induced a decrease of pLAD diameter, and PAP injection in dLAD dit not modify pLAD diameter. In the 7 diabetic patients receiving L-arg, responses to CPT and PAP were not modified. Conversely in the 10 patients receiving DFX, pLAD dilated in response to the 2 tests. Intracoronary isosorbide dinitrate, an endothelium-independent dilator, produced similar dilation in the 2 groups (+20 +/- 8% and +16 +/- 6%, respectively).
assistant
1) responses of angiography normal CA to CPT and to flow increase are impaired in diabetic patients; 2) abnormal responses are not improved by L-arg suggesting that a deficit in substrate for NO synthesis is not involved; 3) DFX restores a vasodilator response to the 2 tests suggesting that inactivation of NO by superoxide radicals might be partly responsible of the impairment of CA dilatation in diabetic patients. Final Decision: yes