Lesion

Damaged area in the brain or spinal cord caused by demyelination (also called plaque or sclerosis).

Leukocyte

White blood cell.

Lymphocyte

A type of white blood cell that is part of the immune system. Lymphocytes can be subdivided into 2 main groups: B lymphocytes, which originate in the bone marrow and produce antibodies; T lymphocytes, which are produced in the bone marrow and mature in the thymus. Helper T lymphocytes heighten the production of antibodies by B lymphocytes; suppressor T lymphocytes suppress B lymphocyte activity and seem to be in short supply during an MS exacerbation.

Macrophage

A white blood cell with scavenger characteristics that has the ability to ingest and destroy foreign substances such as bacteria and cell debris.

Magnetic resonance imaging (MRI)

A diagnostic procedure that produces visual images of different body parts without the use of x-rays. Nuclei of atoms are influenced by a high-frequency electromagnetic impulse inside a strong magnetic field. The nuclei then give off resonating signals that can produce pictures of parts of the body. An important diagnostic tool in MS, MRI makes it possible to visualize and count lesions in the white matter of the brain and spinal cord. A MRI can be used to detect plaques or scarring that might be caused by MS in the brain and spinal cord

Malaise

A general feeling of bodily discomfort and being unwell.

MHC Class II modulation

A treatment for RRMS that is presumed to change the way the immune system responds by working on inflammatory cells outside and inside the CNS.

Minimal Record of Disability (MRD)

A standardized method for quantifying the clinical status of a person with MS. The MRD is made up of 5 parts:

Demographic information

    • The Neurological Functional Systems (developed by John Kurtzke), which assign scores to clinical findings for each of the various neurologic systems in the brain and spinal cord (pyramidal, cerebellar, brainstem, sensory, visual, mental, bowel and bladder)
    • The Disability Status Scale (developed by John Kurtzke), which gives a single composite score for the person's disease
    • The Incapacity Status Scale, which is an inventory of functional disabilities relating to activities of daily living
    • The Environmental Status Scale, which provides an assessment of social handicap resulting from chronic illness

　

The MRD has 2 main functions: to assist doctors and other professionals in planning and coordinating the care of people with MS, and to provide a standardized means of recording repeated clinical evaluations of individuals for research purposes

Monoclonal antibodies

Laboratory-produced antibodies, which can be programmed to react against a specific antigen in order to suppress the immune response.

Motor neurons

Nerve cells of the brain and spinal cord that enable movement of various parts of the body.

MRI

Magnetic resonance imaging. A diagnostic procedure that produces visual images of different body parts without the use of x-rays. Nuclei of atoms are influenced by a high-frequency electromagnetic impulse inside a strong magnetic field. The nuclei then give off resonating signals that can produce pictures of parts of the body. An important diagnostic tool in MS, MRI makes it possible to visualize and count lesions in the white matter of the brain and spinal cord.

Multiple Sclerosis

A disease that attacks the CNS. With MS, the immune system creates swelling and causes damage to the nerve covering (called myelin) that protects the nerve fibers in the brain and spinal cord. This damage prevents nerve cells from communicating properly to relay signals to and from other parts of the body.

Muscle tone

A characteristic of a muscle brought about by the constant flow of nerve stimuli to that muscle, which describes its resistance to stretching. Abnormal muscle tone can be defined as: hypertonus (increased muscle tone, as in spasticity); hypotonus (reduced muscle tone [flaccid paralysis]); or atony (loss of muscle tone). Muscle tone is evaluated as part of the standard neurological exam in MS.

Myelin

A soft, white coating that surrounds and protects nerve fibers in the central nervous system (CNS) and the peripheral nervous system. Myelin serves as insulation and as an aid to efficient nerve fiber conduction. Myelin also helps nerve fibers conduct electrical impulses. When myelin is damaged in MS, nerve fiber conduction is faulty or absent. Impaired bodily functions or altered sensations associated with those demyelinated nerve fibers are identified as symptoms of MS in various parts of the body.

Myelin basic protein

Proteins associated with the myelin of the central nervous system that may be found in higher than normal concentrations in the cerebrospinal fluid of individuals with MS and other diseases that damage myelin.

Myelitis

An inflammatory disease of the spinal cord. In transverse myelitis, the inflammation spreads across the tissue of the spinal cord, resulting in a loss of its normal function to transmit nerve impulses up and down, as though the spinal cord had been severed.

Myelogram

An x-ray procedure by which the spinal canal and the spinal cord can be visualized. It is performed in conjunction with a lumbar puncture and injection of a special x-ray contrast material into the spinal canal.