Other proteins which have been implicated in the formation of senile plaques , but so far are not known to have any genetic linkage to AD , include proteoglycans ( Snow et al . , 1987 ) , apoA 1 ( Wisniewski et al . , 1995a ) , alpha 1 antichymotrypsin ( Abraham et al . , 1988 ) , HB GAM ( Wisniewski et al . , 1996a ) , complement components ( McGeer & Rogers , 1992 ) , acetylcholinesterase ( Friede , 1965 ) , and NAC ( Ueda et al . , 1993 ) . ^^^