Homocysteine and nicotinic acid

The September issue of the Cleveland Clinic Heart Advisor mentions the AHA scientific statement regarding homocysteine  which indicates that nicotinic acid may elevate homocysteine levels.  I am having trouble locating references regarding the homocysteine/nicotinic acid relationship?  Can you suggest references or indicate more precisely the dosages of nicotinic acid involved and the degree of elevation in the homocysteine level?

[CCF CARDIO MD - DLB]

Niacin, especially in larger doses of several grams per day can elevate homocysteine levels, perhaps by interfering with the actions of Vitamin B6. The clinical significance of this is uncertain and it is unclear if Vitamin B6 supplementation can alter this action. While elevated homocysteine does appear to be a risk factor for heart disease, the benefits of niacin in lowering LDL cholesterol and raising HDL cholesterol are better established.