Another study [23] showed that tricyclodecan-9–yl—xanthogenate (D609) was beneficial after cerebral infarction by inhibiting sphingomyelin synthase (SMS), increasing ceramide levels, and induction of cell-cycle arrest by up-regulating p21 and causing hypophosphorylation of retinoblastoma (Rb). The gene discussed is RB1; the disease is brain infarction.