These results indicate that vitamin D deficiency has a negative impact on cortical peri-implant bone formation in ovariectomized rats, which can be compensated by vitamin D supplementation. This study provides first insight into the potential beneficial effect of vitamin D supplementation in implant dentistry.

Background-Peroxynitrite generated from nitric oxide (NO) and superoxide (O 2 Ϫ ) contributes to ischemia/reperfusion (I/R) injury. Feedback inhibition of endothelial NO synthase by NO may inhibit O 2 Ϫ production generated also by endothelial NO synthase at diminished local L-arginine concentrations accompanying I/R. Methods and Results-During hindlimb I/R (2.5 hours/2 hours), in vivo NO was monitored continuously (porphyrinic sensor), and high-energy phosphates, reduced and oxidized glutathione (chromatography), and I/R injury were measured intermittently. Rabbits receiving human serum albumin (HSA) (controls) were compared with those receiving S-nitroso human serum albumin (S-NO-HSA) beginning 30 minutes before reperfusion for 1 hour or 30 minutes before ischemia for 3.5 hours (0.1 mol · kg Ϫ1 · h Ϫ1 ). The onset of ischemia led to a rapid increase of NO from its basal level (50Ϯ12 nmol/L) to 120Ϯ20 and 220Ϯ15 nmol/L in the control and S-NO-HSA-treated groups, respectively. In control animals, NO dropped below basal levels at the end of ischemia and to undetectable levels (Ͻ1 nmol/L) during reperfusion. In S-NO-HSA-treated animals, maximal NO levels never decreased below basal concentration and on reperfusion were 100Ϯ15 nmol/L (S-NO-HSA preischemia group, 175Ϯ15 nmol/L). NO supplementation by S-NO-HSA led to partial and in the preischemia group to total preservation of high-energy phosphates and glutathione status in reperfused muscle (eg, preischemia groups: ATP, 30.23Ϯ5.02 mol/g versus control, 15.75Ϯ4.33 mol/g, PϽ0.0005; % oxidized glutathione, 4.49Ϯ1.87% versus control, 22.84Ϯ6.39%, PϽ0.0001). S-NO-HSA treatment in all groups led to protection from vasoconstriction and reduced edema formation after reperfusion (eg, preischemia groups: interfiber area, 12.94Ϯ1.36% versus control, 27.83Ϯ1.95%, PϽ0.00001). Conclusions-Long

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