A Study To Observe Safety And Blood Concentrations Of PF-04995274 During And Following the Administration of Multiple Doses Of PF-04995274 In Healthy Adult And Healthy Elderly Volunteers.

Inclusion Criteria: * For Healthy adult volunteers: healthy male and/or female subjects of non child bearing potential between the ages of 18 and 55 years, inclusive. (Healthy is defined as no clinically relevant abnormalities identified by a detailed medical history, full physical examination, including blood pressure and heart rate measurement, 12 lead ECG and clinical laboratory tests.) * For Healthy Elderly volunteers: healthy male and/or female subjects of non child bearing potential between the ages of 65 and 85 years, inclusive. Subjects must be in reasonably good health as determined by the investigator based on a detailed medical history, full physical examination (including blood pressure and pulse rate measurement), 12 lead ECG and clinical laboratory tests. Subjects with mild, chronic, stable disease (eg, controlled hypertension, non-insulin dependent diabetes, osteoarthritis) may be enrolled if deemed medically prudent by the investigator. In order to ensure an age range relevant to the Alzheimer's Disease (AD) population, no more than 30% of subjects enrolled in any cohort may be less than 70 years of age. Exclusion Criteria: * Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurologic, or allergic disease (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at time of dosing).