Biomedical subjects
A S Smith
Publications and source records attributed to A S Smith.
The significance of asymmetry of the foramen of Vesalius.
The foramen of Vesalius is a small, variable but consistently symmetrical structure located anteromedial to the foramen ovale and lateral to the foramen rotundum and vidian canal. It transmits an emissary vein through which the cavernous sinus and pterygoid plexus communicate. Fifty high-resolution CT scans of the skull base and two three-dimensional (Cemax) reconstructions were reviewed to determine criteria for defining the normal appearance of the foramen of Vesalius. Three normal types were classified: (1) a well-formed foramen, 1-2 mm in size (n = 32); (2) lack of visualization of the foramen (n = 11); and (3) partial assimilation of the foramen with the foramen ovale (n = 7). The foramen was remarkably symmetric in a large number of cases (n = 48). Asymmetry signified abnormality in four of the six cases. Abnormal causes of asymmetry included invasion by nasopharyngeal melanoma, angiofibroma, carotid cavernous fistula with drainage through the emissary vein, and neurofibromatosis. Thus, for these usually symmetric foramina of Vesalius, asymmetry is more likely the result of a pathologic process than a normal variant.
Menkes kinky hair disease: characteristic MR angiographic findings.
We report two cases of Menkes kinky hair disease in which MR and MR angiography were performed. The clinical and imaging features are reviewed. MR demonstrated characteristic cerebrovascular tortuousity and thus may be a valuable aid in diagnosis and follow-up.
MRA detection of vascular occlusion in a child with progeria.
We report a case of progeria and the utility of visualizing the cerebrovascular anatomy by using MR angiography. A 4-year-old child with Hutchinson-Guilford syndrome developed symptoms of ischemia and MR angiography showed bilateral occlusion of internal carotid and vertebral artery origins; the anterior spinal artery was prominent.
A more diversified America: state and local population changes, 1990-1997.
Recently, the U.S. Bureau of the Census released state and county population estimates with age, gender, race and Hispanic origin detail for 1990-1997. These estimates illustrate the changing demographics of the United States. The 1997 state population estimates show that both Texas and Georgia experienced notable population growth since 1990. Texas replaced New York as the second largest state; Georgia bumped North Carolina from the list of top 10 most populous states to become the state with the 10th largest population. In both Texas and Georgia, migration flows have contributed to the population change. Texas is one of the most popular "intended states of residence" for international migrants, many coming from Latin American countries. On the other hand, Georgia's growth has largely been influenced by "rustbelt" to "sunbelt" domestic migration. At the county level, the largest total population increases again occurred in western and southern states. Population estimates for Asian and Pacific Islanders show that this population remained concentrated in the West in 1997. Similarly, the Hispanic population is primarily concentrated in southwestern states. However, as the Asian and Pacific Islander and Hispanic populations continue to grow, there is spillover into other regions, primarily the larger metropolitan areas in the South, including Washington, DC, and Atlanta, GA. The population projections produced by the Census Bureau indicate that racial and ethnic diversity will continue to increase in the United States well into the next century.