When does a ganglion become a brain? Evolutionary origin of the central nervous system.

A brain, a neural structure located in the head, differs from a ganglion by the following characteristics: (1) a brain subserves the entire body, not just restricted segments; (2) it has functionally specialized parts; (3) it is bilobar; (4) commissures and neurons form the surface with axons in the central core; (5) interneurons are more numerous than primary motor or primary sensory neurons; and (6) multisynaptic rather than monosynaptic circuits predominate. A "cephalic ganglion" does not exist in any living animal and probably never occurred even in extinct ancestral species. It also is not a developmental stage in the ontogenesis of any vertebrate.

Combined angioma and glioma (angioglioma).

Ten patients in whom tissue proliferation akin to angioglioma occurred within the brain are described; seven of the lesions were supratentorial and three infratentorial. Only 31 accepted instances of such neoplasms have been found in the literature. The combined lesions usually become symptomatic in the second and third decades.

Essential hypertension: a sign in search of a disease.

The concept of disease is of cardinal importance in medical practice. The current definition has developed over more than 200 years. It includes a distinctive natural history and identifiable cellular changes.

Epidermoid tumors. Review of the literature.

Reports of epidermoid tumors from 1965 through 1986 were reviewed with emphasis on new and unusual findings. Clinical data considered were rapid onset, rare symptoms, size and rate of growth, and complications. Uncommon locations included multiple sites in one patient and the anterior fontanelle.