Eligibility Details:  
        -  Since the study of gene expression and epigenetic regulation are essential aims of
             GESTALT, all participants are required to consent to DNA/RNA testing and storage at
             the Screening Visit and all subsequent Follow-up Visits. Participants that refuse
             genetic testing and storage will not be eligible to participate or to continue to
             participate in the study.
        The criteria below pertain only to the Screening and Baseline Visits, except where
        otherwise noted. If any of the conditions develop while the participant is in the study,
        the participant remains in the study. In particular, participants who develop neurological
        or motor problems from medical conditions such as stroke or Parkinson s disease may be
        retained in the study, although they are excluded from specific testing in which their
        underlying health condition is an exclusion criterion. Participants that develop severe
        cognitive problems and are diagnosed by the cognition group with dementia, will no longer
        be able to participate in the study.
        Inclusion Criteria:
          -  Age greater than or equal to 20 years of age.
          -  Are willing to return every 2 years for study visit procedures.
          -  Agree to genetic (DNA/RNA) sample collection, analysis and storage.
          -  Have good venous access for cytapheresis and are in good health as
        determined by the Apheresis Health History Questionnaire and are found eligible for
        apheresis (Apheresis Eligibility form).
          -  Weigh greater than or equal to 110lbs and a body mass index (BMI) < 30.
          -  Do not have established genetic diseases such as sickle cell, hemochromatosis (iron
             overload), cystic fibrosis or Ehlers-Danlos syndrome (connective tissue disorder).
          -  Do not have autoimmune diseases such as Hashimoto s thyroiditis, Myasthenia Gravis or
             Rheumatoid arthritis.
          -  Report that they are able to perform daily self- care without assistance.
          -  Report that they able to walk independently for at least 400 meters without assistance
             and without developing severe symptoms.
          -  Report they are able to perform normal activities of daily living without shortness of
             breath (walking or climbing stairs) or other severe symptoms.
          -  Do not have cognitive impairment based on mental status screening tests and
             evaluations. MMSE < 26) .
          -  Do not have a history of cardiovascular disease or cerebrovascular disease including
             angina (requiring treatment), myocardial infarction, congestive heart failure,
             uncontrolled hypertension, pacemaker, stroke or transient ischemic attacks (TIA).
          -  Do not have a history of diabetes (requiring any medical treatment other than diet and
             exercise) and their fasting Glucose is <126 mg/dL.
          -  Do not have active (any activity in the last 10 years) cancer, except for locally
             limited basal cell cancer.
          -  Do not have clinically significant hormonal dysfunction (Self-reported or laboratory
             values out of range. Mild hypothyroidism in participants over 60 is not considered
             exclusion).
          -  Do not have a history of neurological diseases or birth defects (other than minor
             anatomical abnormalities, which do not affect physical and/or cognitive function).
          -  Do not have a history of kidney or liver disease (associated with reduced kidney or
             liver function).
          -  Do not have a history of severe gastrointestinal (G.I.) diseases, with symptoms or
             requiring chronic treatment such as gastroesphageal reflux disease (GERD), Crohn s
             disease or ulcerative colitis.
          -  Do not have a history of severe pulmonary disease such as chronic obstructive
             pulmonary disease (COPD) or asthma requiring continuous medication use.
          -  Do not have muscle-skeletal conditions due to diseases or traumas (that cause
             pathological weakness and/or chronic pain).
          -  Do not have a history of severe psychiatric conditions associated with behavioral
             problems or requiring absolute and continuous need for medical treatment.
          -  Do not have any medical condition that requires absolute and continuous need for long
             term treatment with antibiotics, corticosteroids, immunosuppressors, H2 blockers
             and/or proton pump inhibitors, or pain medications.-Do not have a medical condition
             that requires the use of chronic anticoagulant medication such as Coumadin, heparin or
             antiplatelet agents other than low dose aspirin.
          -  Do not have important sensory deficits (legally blind and/or any condition that
             precludes the participant from being tested with standard neuropsychological tests or
             providing informed consent).
          -  Are able to read and speak English.
          -  Are able to understand the study risks and procedures, and consent to participate in
             the study.
          -  Not currently pregnant or a nursing mother.
          -  Do not currently smoke and have not smoked in the past 3 months.
          -  Veins are adequate for cytapheresis
          -  No current illness that as judged by the study physician substantially increases the
             risks associated with cytapheresis (active infections, allergies, etc.).
          -  No history of allergy to acid- citrate- dextrose (ACD) anticoagulant.
          -  No history of an active bleeding disorder such as hemophilia or Von Willebrand
             disease.
          -  No history of seizures within the last 3 months.
          -  No history of Lyme disease, unless six weeks post treatment and no new symptoms, of
             Chagas disease, Babesiosis, or Leishmanias.
          -  Are not claustrophobic and are eligible to perform MRI as per the MRI eligibility form
          -  Do not have hip or knee replacements or other medical conditions that prevent MRI
             research scans from being performed
        Participant Exclusion Criteria:
        These criteria pertain to the Screening and Baseline Visits. If conditions considered as
        exclusion criteria for study entry develop any time after the baseline evaluation, the
        participant remains in the study.
        Exclusion Criteria:
          -  HIV virus infection.
          -  Hepatitis B or C.
          -  Active syphilis, gonorrhea or TB requiring treatment.
          -  WBC <3,000 or > 12,000/mcrL.
          -  Platelets < 100,000 or >600,000 /mcrL.
          -  Hemoglobin < 11.0 g/dL in women and < 12.0 in men.
          -  Creatinine >1.6 mg/dl or calculated creatinine clearance < 50 cc/min.
          -  Bilirubin > 1.5 mg/dl (unless higher levels can be ascribed to Gilbert s disease.
          -  ALT, AST or alkaline phosphatase twice the normal serum concentration.
          -  Corrected calcium < 8.5 or > 10.7 mg/dl.
          -  Albumin < 3.1 g/dl.
          -  Positive Urine Drug Screen (unless taking prescribed medication and at the discretion
             of the PI).
        Furthermore, if the participant is found eligible at screening and baseline but fails a
        urine drug screen (unless taking a prescribed medication and at the discretion of the PI)
        at any of the subsequent (follow-up) visits, the participant will be asked to return to
        repeat the test and if positive, will no longer be eligible to participate in the study.
        If female and found to be pregnant during pregnancy screening at any visit, the participant
        will need to reschedule their visit for when they are 3 months postpartum and/or post
        breastfeeding.
        Justification for Exclusion of Women, Minorities, and Children (Special Populations)
        Exclusion of Women: Not Applicable
          -  Pregnancy: Women of child bearing age who become pregnant during the study will be
             deferred from a study visit until they are no longer pregnant and breastfeeding (3
             months post pregnancy and/or breastfeeding).
          -  Exclusion of Children: Participants under the age of 20 years old will not be allowed
             to participate in GESTALT because GESTALT is a study on the aging of adults and does
             not include the developmental growth period of children.
          -  Exclusion of Non-English Speaking Subjects: Due to the complexity of testing/
             procedures and extensive cognitive testing protocols, consents, instructions and
             questionnaires are provided in English. Therefore, all participants must be able to
             able to read and speak English. To date, the NIA located in Baltimore has not had
             non-English speaking participants interested in participating in studies. In regards
             to this study, should this occur in the future, the Principal Investigator, in
             conjunction with the requirements of SOP 12 Requirements of Informed Consent, and more
             specifically 12.9.1 Non-English Speaking Subjects will be used to determine if changes
             related to recruitment and enrollment of non-English speaking participants is needed.