Tuesday, May 20, 2008

Sen. Kennedy - Brain Tumor

Bad medical news for Sen. Edward Kenneday. He has been diagnosed as having a malignant glioma. That diagnosis doesn't tell us everything we need to know. There are two types of nervous tissue cells - neurons and glial cells. Neurons are neurons but there are several different types of glial cells. Glial cells, often called neuroglia cells, provide support and nutrition for neurons. Most neurons are incapable of dividing, but glial cells can divide at different rates. The different types of specific glial cells include:

Oligodendrocytes - these are the cells that form myelin sheaths around nerves in the central nervous system

Ependymal cells - these cells make up the walls of the ventricles or chambers in the brain and produce cerebralspinal fluid

Astrocytes - these important cells are the most abundant glial cells in the brain. They form the blood-brain barrier, provide nutrition for neurons and have a role in brain repair

Radial glia - are important during brain development

Microglia - are glial cells that are phagocytic. This is the cell that provides the first line of defense against infection of the brain

So there are astrocytomas, ependymomas and oligodendroglioma (pretty rare) as possibilities. Grade IV astrocytomas called glioblastoma multiformi are very dangerous, account for over half of primary brain tumors and have a very poor survival rate. Ependymomas are more commonly found in children when they occur in the brain itself. They only make up about 5% of adult cranial tumors. Oligodendrogliomas are usually found in middle aged adults and account for about 9% of cranial tumors in adults.

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