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Alzheimer's
Disease
Alzheimer's disease (AD) is a neurodegenerative
disorder mainly characterized by the progressive and irreversible
loss of nerve cells (neurons) located in specific brain areas: the
hippocampus and the cortex of the brain. AD is a disease that causes
impaired memory, thinking, and behavior.
Amygdala
Part of the brain associated with feeling emotions.
Amyloid beta & plaques
Amyloid precursor protein (APP) is a molecule present in the brain
that is thought to help neurons grow and survive.
Biomarker
A biochemical feature or facet that can be used to measure the progress
of disease or the effects of treatment
CSF
CSF is a clear liquid that surrounds the structures of the central
nervous system (the brain and spinal cord). Studying CSF provides
scientists with a “biochemical window” into the brain,
because many important brain chemicals are also found in CSF. By
studying the chemicals found in CSF, including some of the abnormal
proteins that accumulate in AD, scientists can learn more about
the disease. Important information already exists about using CSF
to develop an early and accurate diagnostic test for AD.
Cognition
The process of knowing and, more precisely, the process of being
aware, knowing, thinking, learning and judging. The study of cognition
touches on the fields of psychology, linguistics, computer science,
neuroscience, mathematics, ethology and philosophy.
Cortisol
The major adrenal glucocorticoid that stimulates
conversion of proteins to carbohydrates, raises blood sugar levels
and promotes glycogen storage in the liver.
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Dementia
Significant loss of intellectual abilities such as memory capacity,
severe enough to interfere with social or occupational functioning.
Criteria for the diagnosis of dementia include impairment of attention,
orientation, memory, judgment, language, motor and spatial skills,
and function.
Diabetes
Diabetes mellitus is a group of diseases characterized by high levels
of blood glucose. It results from defects in insulin secretion,
insulin action, or both. There are two types of diabetes:
By far the most common isType 2 diabetes (previously
called adult onset diabetes or non-insulin dependent diabetes).
Type 2 diabetes results from a defect in insulin action. Actually
individuals at risk for developing type 2 diabetes often have elevated
insulin levels, but the insulin does not work properly. This phenomenon
is called insulin resistance. The main risk factors for type 2 diabetes
are genetic and obesity and/or physical inactivity. Type 2 diabetes
is often associated with high blood pressure and abnormal lipid
profiles (elevated cholesterol). In addition, diabetes can be associated
with serious complications and premature death, but people with
diabetes can take measures to reduce the likelihood of such occurrences.
Type 1 diabetes refers to individuals who have an inability
to secrete sufficient insulin to control glucose levels bacause
of some damage to the cells in the pancreas that produce insulin.
This damage can result from some viral infection or/and the body
reacting against it's own insulin producing cells. Most children
who are not obese who develop diabetes have this form of the diabetes
(other names are juvenile diabetes or insulin-dependant diabetes).
However, if type 2 diabetes is not treated appropriately it may
result in the need for insulin administration.
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Endocrine
Pertaining to hormones and the glands that make and secrete them
into the bloodstream through which they travel to affect distant
organs.
A group of specialized cells that release hormones into the blood.
For example, the islets in the pancreas, which secrete insulin,
are endocrine glands.
Fluoroscopy
Fluoroscopy is a technique for obtaining “live” x-ray
images of a patient. A radiologist can then watch the images “live”
on a television monitor. Fluoroscopy is often used to observe human
anatomy as well as the actions of any instruments used during radiological
procedures.
Global deterioration
scale
(GDS) scale used by physician to measure progression of AD.
Glucose
The simple sugar (monosaccharide) that serves as the chief source
of energy in the body. Glucose is also known as dextrose.Glucose
is the principal sugar the body makes. The body makes glucose from
proteins, fats and, in largest part, carbohydrates. Glucose is carried
to each cell through the bloodstream. Cells, however, cannot use
glucose without the help of insulin.
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Hippocampus
An area buried deep in the forebrain that helps regulate emotion
and memory. Functionally, the hippocampus is part of the olfactory
cortex, that part of the cerebral cortex essential to the sense
of smell. Certain antidepressants (such as fluoxetine, or Prozac)
influence the birth of new neurons in the hippocampus. The hippocampus
is so-called because its shape suggests that of a seahorse. From
the Greek hippos (horse) = kampos (a sea monster). In AD, it is
the earliest structure to be most severely damaged, causing the
obvious memory loss for which this disease is known.
Impaired
Glucose Tolerance (IGT)
Refers to an impaired ability of the individual to efficiently move
glucose from the blood into the tissues where it belongs. This is
a pre-diabetic condition where fasting glucose levels are generally
normal but after a meal or a glucose load (such as during a Glucose
Tolerance Test), the sugar in the blood stays high for longer than
it should. This is due to the presence of significant insulin
resistance. Impaired glucose tolerance (IGT) is established
by performing a Glucose Tolerance Test. When the blood glucose level
two hours after ingestion of the glucose load (the sweet drink)
is between 140 mg/dl and 200 mg/dl this indicates IGT. Two-hour
glucose levels above 200 mg/dl indicate diabetes.
Insulin
A natural hormone made by the pancreas that controls the level of
the sugar glucose in the blood. Insulin permits cells to use glucose
for energy. Insulin is also used in other processes, including the
brain, but this is not well understood.
Insulin
resistance
Many cells such as muscle and fat depend on insulin to transport
glucose from the blood to inside the cell. When the tissue does
not respond well to insulin and requires higher insulin levels to
do the same work, this is called insulin resistance. Insulin resistance
is a precursor to diabetes.
Metabolism
Metabolism is the whole range of biochemical processes that occur
within us (or any living organism). Metabolism consists both of
anabolism and catabolism (the buildup and breakdown of substances,
respectively). The term is commonly used to refer specifically to
the breakdown of food and its transformation into energy.
Mild Cognitive
Impairment
Mild cognitive impairment (MCI) is a disorder of the brain in which
nerve cells involved in one aspect of cognitive processing (thinking
abilities) are impaired. Most (but not all) patients with MCI develop
a progressive decline in their thinking abilities over time, and
Alzheimer's disease is usually the underlying cause.
MRI
scan
Abbreviation and commonly used nickname for magnetic
resonance imaging. A procedure
using a magnet connected to a computer to create images of internal
structures of the body, especially the soft tissues. An MRI uses
the influence of a large magnet to polarize hydrogen atoms in the
tissues and then monitor the summation of the spinning energies
within living cells. MRI images, particularly with soft tissue,
brain and spinal cord, abdomen and joints, are clear and can be
superior to the usual X-ray image.
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Neurofibrillary
tangles
Abnormal structures formed inside nerve cells in AD. Their presence
cause dysfunction of nerve cells and eventually kills them. Neurofibrillary
tangles are composed of tau protein.
Neuroimaging
A clinical specialty concerned with producing images of the brain
by noninvasive techniques (as computed tomography, magnetic resonance
imaging, and positron-emission tomography).
Neuron
A nerve cell that sends and receives electrical signals over long
distances within the body. A neuron may send electrical output signals
to muscle neurons (called motor neurons or motoneurons) and to other
neurons. A neuron may receive electrical input signals from sensory
cells (called sensory neurons) and from other neurons. A neuron
that simply signals another neuron is called an interneuron. The
brain consists of neurons, as well as many other cell types. There
are approximately 100 billion neurons in the human brain. Each has
a cell body, many dendrites, and an axon. The cell body consists
of a nucleus, which controls the cell’s activities, as well
as several other structures important for it’s function. Each
neuron is connected to thousands of other nerve cells through its
dendrites and axons. Dendrites are mainly responsible for receiving
messages from other neurons, while the axon transmits messages away
from the cell body, either to other nerve cells’ dendrites,
or directly to muscles and glands. Neurons are surrounded by glial
cells, which provide them with protection, support, and nourishment.
Pathophysiology
The functional changes that accompany a particular syndrome or disease
PET scan
Positron emission tomography,
a highly specialized imaging technique using short-lived radioactive
substances. This technique produces three-dimensional colored images.
PET scanning provides information about the body's chemistry not
available through other procedures. Unlike CT (computerized tomography)
or MRI (magnetic resonance imaging), which look at anatomy or body
form, PET studies metabolic activity or body function. PET has been
used primarily in cardiology, neurology, and oncology. In particular,
it has been used to assess the benefit of coronary artery bypass
surgery, identify causes of childhood seizures and adult dementia,
and detect and grade tumors. It is very sensitive in picking up
active tumor tissue but does not measure the size of it.
Physiology
The study of how living organisms function including such processes
as nutrition, movement, and reproduction.
Plaques
Local buildup of amyloid-B in the brain of AD patients, damaging
nerve cells and destroying connections between them.
Protein
Any of numerous naturally occurring extremely complex substances
(as an enzyme or antibody) that consist of amino acid residues joined
by peptide bonds, contain the elements carbon, hydrogen, nitrogen,
oxygen, usually sulfur, and occas. other elements (as phosphorus
or iron), that are essential constituents of all living cells, that
are synthesized from raw materials by plants but assimilated as
separate amino acids by animals, that are both acidic and basic
and usually colloidal in nature although many have been crystallized,
and that are hydrolyzable by acids, alkalies, proteolytic enzymes,
and putrefactive bacteria to polypeptides, to simpler peptides,
and ultimately to alpha-amino acids
Tau
protein
Abnormal protein that in AD piles up inside nerve cells, forming
neurofibrillary tangles that directly lead to death of nerve cells.
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