NGF and myeloid sarcoma: In order to further understand NGF’s neurotrophic effects on FF-lesioned MS neurons, the present study evaluated three topics: 1) the amount of NGF in the CSF infused by mini-osmotic pumps was evaluated at several time points during a fourteen day time period; 2) the dose response to NGF in injured MS neurons was compared using the infusion method versus a daily injection administration; 3) the response of injured MS neurons was evaluated with varying intervals of NGF injections over a fourteen day time period.