Glossary
acetylcholine
A chemical in the brain and at the muscle that acts as a neurotransmitter.
activities of daily living (ADLs)
Personal care activities necessary for everyday living, such as eating, bathing, grooming, dressing, and using the toilet; a term often used by healthcare professionals to assess the need and/or type of care a person may require.
advance directives
Documents (such as a Living Will) completed and signed by a person who is legally competent to explain wishes for medical care should he or she become unable to make those decisions at a later time.
agonist
A drug that increases neurotransmitter activity by directly stimulating the nerve cell receptors.
ALS (amyotrophic lateral sclerosis)
A chronic, progressive disease marked by gradual degeneration of the nerve cells in the central nervous system that control voluntary muscle movement. The disorder causes muscle weakness and atrophy; symptoms commonly appear in middle to late adulthood, with death in two to five years. The cause is unknown, and there is no known cure. Also called Lou Gehrig's Disease, or Motor Neuron Disease.
amino acid
One of the 20 building blocks of protein.
antibody
A defense protein that binds to foreign molecules to allow elimination of the foreign molecule.
antigen
Substances that are capable of causing the production of antibodies. Antigens may or may not lead to an allergic reaction.
antioxidant
A chemical compound or substance that inhibits oxidation.
assay
A method to analyze or quantify a substance in a sample. An assay is an analysis done to determine: 1. The presence of a substance and the amount of that substance. 2. The biological or pharmacological potency of a drug.
atrophy
The progressive loss of muscle mass, or wasting, caused by reduction in the size or number of muscle cells. It is one of the later symptoms of ALS.
axon
The single, hair-like extension of a nerve cell that carries a message away from the cell body to the next nerve cell or to muscle.
bioassay
Determination of the potency or concentration of a compound by its effect upon animals, isolated tissues, or microorganisms, as compared with an analysis of its chemical or physical properties.
biochemistry
The chemistry of biology; the application of the tools and concepts of chemistry to living systems. Biochemists study the structures and physical properties of biological molecules.
bioinformatics
The process of developing tools and processes to quantify and collect data to study biological systems logically.
blood-brain barrier (BBB)
A protective barrier formed by the blood vessels and glia of the brain. It prevents some substances in the blood, including some drugs, from entering brain tissue.
bulbar ALS
Bulbar ALS is the type in which onset symptoms are in the facial muscles, speech and swallowing.
bulbar muscles
The muscles that control the speech, chewing and swallowing.
central nervous system (CNS)
The brain and spinal cord combined.
cerebro-spinal fluid (CSF)
A watery fluid, continuously produced and absorbed, which flows in the cavities within the brain and around the surface of the brain and spinal cord.
cerebro-spinal fluid analysis (spinal tap)
A procedure used to isolate cerebrospinal fluid for evaluation or diagnosis of disease.
chromosome
The structures in a cell’s nucleus that carries genetic information (DNA).
computed tomography (CT or CAT scan)
A non-invasive X-ray procedure that takes cross-sectional images of the brain or other internal organs. It detects abnormalities that may not show up on an ordinary x-ray.
dendrite
Extensions from the neuron cell body that take information to the cell body. A single nerve may possess many dendrites.
DNA
One of two types of molecules that encode genetic information
dopamine
A chemical substance, a neurotransmitter, found in the brain that regulates movement, balance, and walking.
dysarthria
Impaired speech and language due to weakness or uncoordination in the muscles used for speaking.
electrodiagnostic tests
Studies including electromyography (EMG) and nerve conduction velocity ( NCV), that evaluate and diagnose disorders of the muscles and motor neurons. Electrodes are inserted into the muscle, or placed on the skin overlying a muscle or muscle group, and electrical activity and muscle response are recorded.
electroencephalogram (EEG)
A method of recording the brain's continuous electrical activity by means of electrodes attached to the scalp.
enzyme
A protein that acts as a catalyst in mediating and speeding a specific chemical reaction.
excitotoxicity
The condition in which overstimulation of neurons can over time lead to neuronal death.
extensor muscle
Any muscle that causes the straightening of a limb or other part.
familial ALS
A progressive neurological disease that affects more than one member of the same family. This type of ALS accounts for a small percentage of people with ALS in the United States (5 to 10 percent).
fasciculation
Small, involuntary, irregular, visible contractions of individual muscle fibers. Often seen in the legs, arms and shoulders of ALS patients. This is often described by people with ALS as "persistent rolling beneath the skin."
FDA
U.S. Food and Drug Administration, the branch of federal government which approves new drugs for sale.
flaccid muscles (also hypotonicity)
A condition characterized by a decrease or loss of normal muscle tone due to the deterioration of the lower motor nerve cells.
flexor muscle
Any muscle that causes the bending of a limb or other body part.
formulation chemistry
Formulation is a process by which a compound is prepared in a suitable form for administration to animals or human being depending on the dose, route and target tissue.
free radicals
Chemicals that are highly reactive and can oxidize other molecules (i.e. Superoxide).
ganglion
A cluster of nerve cell bodies.
GDNF (glial derived neurotrophic factor)
GDNF is a naturally occurring growth factor that proved capable of protecting and promoting the survival of motor neurons in animal studies. A growth factor is a growth inducing protein found in the human body. There is research interest in these naturally occurring proteins that have a supportive, reparative, or protective role for motor neurons in animals.
Gehrig, Lou
(1903-1941), American professional baseball player, also known as the Iron Horse because he established a record for the most consecutive games played by a professional baseball player, appearing in 2130 games from 1925 to 1939. From 1923 until 1939 he played first base for the New York Yankees of the American League. Gehrig was twice voted the league's most valuable player (MVP). Stricken with the ALS, which later became known as Lou Gehrig's disease, he retired from baseball in 1939.
gene
Genes are the basic biological units of heredity. They are composed of DNA.
genome
All of the genetic information; the entire genetic complement; all of the hereditary material possessed by an organism.
glutamate
Glutamate is one of the most common amino acids found in nature. It is a main component of many proteins, and is present in most tissues. Glutamate is also produced in the body and plays an essential role in human metabolism. It is a primary excitatory neurotransmitter in the human CNS. Over-stimulation of these receptors is thought to trigger the neuronal damage associated with a wide variety of neurological insults and diseases, including amyotrophic lateral sclerosis (ALS), lathyrisms, and Alzheimer's disease.
growth factor
A naturally occurring protein chemical that stimulates cell division differentiation and proliferation. It is produced by normal cells during embryonic development, tissue growth and wound healing.
hyperreflexia
Excessive response of muscle reflexes when a normal stimulus is applied.
hyporeflexia
Weak or absent muscle response when a normal stimulus is applied.
immune system
A complex system that is responsible for distinguishing us from everything foreign to us, and for protecting us against infections and foreign substances. The immune system works to seek and kill invaders.
immunology
The study of all aspects of the immune system including its structure and function, disorders of the immune system, blood banking, immunization and organ transplantation.
incidence
The occurrence of new cases of a condition. The incidence rate describes the frequency with which cases are identified. Incidence is commonly measured in new cases per 1,000 (or 100,000) of population at risk, per year. The incidence of ALS typically varies between 1 and 4 diagnoses per 100,000 of populations per year in Western nations.
incontinence
Involuntary voiding of the bladder or bowel.
inflammation
The nonspecific immune response that occurs in reaction to any type of bodily injury. It is a stereotyped response that is identical whether the injurious agent is a pathogenic organism, foreign body, ischemia, physical trauma, ionizing radiation, electrical energy or extremes of temperature. The reactions produced during inflammation and repair may be harmful (i.e. hypersensitivity reactions, the processes that lead to rheumatoid arthritis, and possibly microglial over-activation in ALS).
inflammatory disease
Diseases that are characterized by activation of the immune system to abnormal levels that lead to disease.
intrathecal
Injection into the innermost cerebrospinal fluid-containing space surrounding the central nervous system. Usually done by lumbar puncture.
Juvenile ALS
ALS2 — also called autosomal recessive juvenile ALS type 3 — manifests around 12 years of age, advances slowly over many years, and takes an especially noticeable toll on the upper motor neurons. It affects a small number of families, mostly in Northern Africa and the Middle East.
ligase
In genetics, the general term for a class of enzymes that speed up the joining of the ends of two chains of DNA.
limb-onset ALS
Refers to the type of ALS in which initial symptoms appear in the limbs. The most common form of ALS, the other type being bulbar-onset ALS.
lower motor neuron
Nerve cells starting at the spinal cord or brain stem and ending at the muscle fibers. The loss of lower motor neurons leads to weakness, twitching of muscles (fasciculations), and loss of muscle bulk (atrophy).
lumbar puncture
A lumbar puncture or "LP" is a procedure whereby spinal fluid is removed from the spinal canal for the purpose of diagnostic testing. It is particularly helpful in the diagnosis of inflammatory diseases of the central nervous system, especially infections, such as meningitis. It can also provide clues to the diagnosis of stroke, spinal cord tumor and cancer in the central nervous system, and now to ALS.
magnetic resonance imaging (MRI)
A non-invasive procedure that produces a two-dimensional view of an internal organ or structure, especially the brain and spinal cord.
metabolomics
The study and identification of metabolic products of cells that may be used to distinguish a disease state from a healthy state.
mitochondria
The mitochondria are the principal energy source of the cell. Mitochondria convert nutrients into energy as well as doing many other specialized tasks.
mitochondrial dysfunction
For ALS, cellular energy production is low in motor neurons. Excessive free radical activity appears to be caused by deficiencies in cellular energy production which is a function normally carried out by mitochondria.
molecule
The smallest unit of a substance that can exist alone and retain the character of that substance.
motor neuron
A neuron that conveys impulses initiating muscle contraction or glandular secretion.
motor neuron disease (MND)
A group of disorders in which motor nerve cells (neurons) in the spinal cord and brain deteriorate and die. ALS is the most common motor neuron disease.
muscle
Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and bowel is called "smooth muscle."
muscle atrophy
Loss of muscle fiber volume characterized by a visible decrease in muscle size. This occurs if muscles no longer receive impulses or signals from nerve cells.
muscular dystrophy
The name given to a group of diseases that are, for the most part, genetically determined and which cause gradual wasting of muscle with accompanying weakness and deformity.
mutation
A permanent change, a structural alteration, in the DNA or RNA. Mutations can be caused by many factors including environmental insults such as radiation and mutagenic chemicals. Mutations are sometimes attributed to random chance events.
myelogram
A procedure that uses dye injected into the spinal canal to make the structure clearly visible on x-rays.
nerves
A bundle of fibers that uses electrical and chemical signals to transmit sensory and motor information from one body part to another.
nervous system
The system of cells, tissues and organs that regulates the body's responses to internal and external stimuli. In vertebrae it consists of the brain, spinal cord, nerves, ganglia and parts of the receptor and effector organs.
neurologist
A physician who specializes in the nervous system and its disorders.
neurology
The medical science that deals with the nervous system and disorders affecting it.
neuromuscular
Of, relating to, or affecting both nerves and muscles.
neuron
Neurons are the nerve cells which make up the central nervous system. They consist of a nucleus, a single axon which conveys electrical signals to other neurons and a host of dendrites which deliver incoming signals.
neuronal receptors
Neurons use chemical signaling mechanisms to communicate with one another. These impulses are transmitted at specialized junctions called synapses. The sending or signaling neuron triggers the release of neurotransmitters (or chemicals) into the synaptic cleft. From there the transmitters bind to receptors on the post synaptic or receiving neuronal cell. These receptors are the gate keepers of neuronal cells and they open and close in response to chemical signals that direct the actions and reactions of the cell.
neuroprotective
The property of protecting a part of the body's nervous system,neuroprotection from conditions that normally cause cell injury or death.
neuroscience
The scientific disciplines concerned with the development, structure, function, chemistry, pharmacology, clinical assessments and pathology of the nervous system.
neurotransmitters
Chemical substances that carry impulses from one nerve cell to another; found in the space (synapse) that separates the transmitting neuron's terminal (axon) from the receiving neuron's terminal (dendrite).
norepinephrine
A neurotransmitter found mainly in areas of the brain involved in governing autonomic nervous system activity, especially blood pressure and heart rate.
onset
The time of appearance of the first symptoms of a condition, prior to seeking diagnosis.
orthostatic hypotension
A large decrease in blood pressure upon standing; may result in fainting.
oxidative stress
Accumulation of destructive molecules called free radicals can lead to cell injury and death. Free radicals damage components of the cells' membranes, proteins or genetic material by "oxidizing" them - the same chemical reaction that causes iron to rust. Some patients with familial ALS have mutations in the gene for superoxide dismutase type 1 (SOD1). SOD1 normally breaks down free radicals, but mutant SOD1 is unable to perform this function.
PEG tube
Percutaneous endoscopic gastrostomy (PEG) tube - a tube placed directly into the stomach through the abdominal wall to provide another way to receive nourishment and liquids.
peristalsis
Wavelike contractions that move food through the digestive tract.
pharmacokinetics
The study of the metabolism and action of drugs with particular emphasis on the time required for absorption, duration of action, distribution in the body and method excretion.
pharmacological properties
A drug's half life, molecular weight, permeability, chemical structure and methods of action through the pathways it affects.
pharmacology
The study of drugs and their origin, nature, properties and effects upon living organisms.
phenotype
The expression of the genes present in an individual. This may be directly observable (eye color) or apparent only with specific tests (blood type). Some phenotypes such as the blood groups are completely determined by heredity, while others are readily altered by environmental agents.
positron emission tomography (PET) scan
A computer-based imaging technique that provides a picture of the brain's activity rather than its structure. The technique detects levels of injected glucose labeled with a radioactive tracer.
primary lateral sclerosis (PLS)
A progressive neurological disease in which the upper motor nerve cells deteriorate. If the lower motor neurons are not affected within two years, the disease usually remains a purely upper motor disease.
progressive bulbar palsy (PBP)
A condition that begins with difficulties in speaking, chewing and swallowing due to lower motor nerve cell (neuron) deterioration. This disorder affects about 25 percent of all people with ALS.
progressive muscular atrophy (PMA)
A progressive neurological disease in which the lower motor nerve cells (neurons) deteriorate.
protein
Proteins are large molecules required for the structure, function, and regulation of the body's cells, tissues, and organs. Each protein has unique functions. Proteins are essential components of muscles, skin, bones and the body as a whole. Protein is also one of the three types of nutrients used as energy sources by the body.
proteomics
The study and identification of the proteins produced by the genetic instructions carried by a cell that may be used to distinguish a diseased state from a healthy state.
protocol
A precise and detailed plan for the study of a biomedical problem or for a regimen of an experimental therapy.
pseudobulbar palsy
A condition characterized by difficulties with speech, chewing and swallowing. These symptoms resemble those of bulbar palsy, but this condition is also characterized by spontaneous or unmotivated crying and laughing.
Rilutek ®
The only FDA-approved drug available to treat ALS. Riluzole is the generic name of Rilutek®.
RNA
A single-stranded strain of ribonucleic acid (RNA). The primary function of RNA is to direct protein synthesis within a cell.
routes of administration
The different ways in which a drug can be delivered (i.e. intravenously, intrathecally, intramuscularly, orally).
sialorrhea
Drooling
side effect
An action or effect of a drug other than that desired. Commonly it is an undesirable effect such as nausea, headache, insomnia, acute toxic reaction or drug interaction.
SOD
See superoxide dismutase.
spasm
A condition in which a muscle or group of muscles involuntarily contract and that is typically painful.
spinal cord
Part of the central nervous system extending from the base of the skull through the vertebrae of the spinal column. It is continuous with the brain stem, and like the brain it is encased in a triple sheath of membranes. Thirty-one pairs of spinal nerves arise from the sides of the spinal cord. The spinal cord carries information from the body's nerves to the brain and signals from the brain to the body.
spinal muscular atrophy (SMA)
A hereditary neurological disease in which only the lower motor nerve cells are affected.
superoxide dismutase
An enzyme that destroys superoxide. One form of the enzyme contains manganese and another contains zinc. Superoxide is a highly reactive form of oxygen. For ALS, 2% of the total population of patients have mutations in the gene for copper/zinc superoxide dismutase type SOD1. SOD1 normally breaks down free radicals, but mutant SOD1 is unable to perform this function.
synapse
A tiny gap between the ends of nerve fibers across which nerve impulses pass from one neuron to another; at the synapse, an impulse causes the release of a neurotransmitter, which diffuses across the gap and triggers an electrical impulse in the next neuron.
therapeutic index
A general way of comparing an effective dose of a drug with its toxicity. A high therapeutic index means a drug’s desired effects are produced at a dose where its toxicities are infrequent and minor.
thrombus
A blood clot
toxicity
The extent, quality or degree of producing injury.
toxicology
Division of medical and biological science concerned with drug safety. Scientists study their chemistry and pharmacological actions, and establish antidotes and treatment of toxic manifestations, prevention of poisoning, and methods for controlling exposure to harmful substances.
toxin
A poisonous substance of animal or plant origin.
treatment
Medical or surgical management of a patient. Any specific procedure used for the cure of or the amelioration of a disease or pathological condition.
trophic factor
One of a class of proteins that help keep cells healthy.
upper motor neurons
Nerve cells (motor neurons) originating in the brain's motor cortex and running through the spinal cord.
Adapted from the U.S. National Library of Medicine, 8600 Rockville Pike, Bethesda, MD 20894, www.nlm.nih.gov/medlineplus