Outcome of moderate carotid artery stenosis in patients who are asymptomatic

PURPOSE: The incidence rate of disease progression and stroke after the diagnosis of a moderate (50% to 79%) carotid stenosis was determined by means of color-flow duplex scanning. METHODS: During a 4-year period, 344 male veterans with moderate internal carotid artery stenoses, on one or both sides, were examined at regular intervals for a mean period of 25 months. Carotid color-flow scans were obtained semiannually. Clinical follow-up was performed to determine the incidence rate of amaurosis fugax, transient ischemic attacks, nonhemispheric symptoms, and strokes. RESULTS: New neurologic symptoms developed in 75 patients (21.8%). Fifty-one (14.8%) had ipsilateral symptoms during follow-up: 18 amaurosis fugax (5.2%), 14 transient ischemic attacks (4%), 5 nonhemispheric symptoms (1.4%), and 14 strokes (4%). Twenty-four patients (6.9%) had contralateral symptoms: 20 strokes (5.8%) and 4 transient ischemic attacks (1.2%). Life-table analysis showed that the annual rate of ipsilateral neurologic events was 8.1%, and the annual rate of stroke was 2.1%. Seventy-five patients (22%) died in the follow-up period. Disease progression to 80% to 99% stenosis or occlusion occurred in 71 of 458 vessels (15.5%). The internal carotid arteries that showed evidence of disease progression had a significantly higher initial peak systolic velocity (251 vs 190 cm/s; P <.0001) and end diastolic velocity (74 vs 52 cm/s; P < 0.0001). Black patients and patients with ischemic heart disease were at a higher risk for disease progression. We could not identify any atherosclerotic risk factors that reliably predicted patients in whom future ipsilateral neurologic symptoms were more likely to develop. However, there was an increased risk of stroke associated with progression of disease. CONCLUSION: Patients who are asymptomatic and who have moderate carotid stenoses are at significant risk for neurologic symptoms and death, but have a relatively low incidence rate of ipsilateral events. The initial flow characteristics in the stenotic vessel are predictive of future disease progression, but they are not helpful in identifying patients in whom symptoms will develop.     

Analysis of multiple geological datasets from the English Lake District

A geological database comprising coregistered Landsat Thematic Mapper (TM) regional multielement stream sediment geochemistry, regional gravity and aeromagnetics, and geological map data has been established, in raster format, for the area of the English Lake District. To study spatial correlations within the database, TM imagery and its first-order structurally enhanced filter derivatives are combined with regional survey data using intensity-hue-saturation transforms and stereoscopic-view generation techniques. These are then overlaid with line and polygon information from other exploration datasets. Datasets are combined in a manner which maintains the identity of each dataset. The imagery produced demonstrates the power of image presentation for efficient multidata analysis.<>     

VOLATILE BASIC COMPOUNDS DERIVED FROM ROASTED BARLEY

By gas chromatography/mass spectrometry twenty-three basic heterocyclic compounds have been identified in an extract from roasted barley. Several other such compounds have been identified tentatively. The classes of compounds include pyridines, pyrazines, thiazoles and oxazoles. Such compounds appear to contribute to the flavour of beer brewed with grists containing roasted barley.