The differentiation of cholesterol and pigment gallstones

Gallbladder biles and stones were obtained at 116 cholecystectomies for symptomatic gallstone disease. All 33 patients younger than 50 years had cholesterol stones, whereas 40% of the older patients had pigment stones. We compared the reliability of three different bile tests for the differentiation between cholesterol and pigment stone patients. Whereas both the presence of cholesterol monohydrate crystals in fresh gallbladder bile and a nucleation time 20 days in ultrafiltered gallbladder bile had a specificity of 100% for cholesterol gallstone disease, biliary supersaturation with cholesterol (cholesterol saturation index >1.0) had a low specificity. The sensitivity of nucleation time 20 days for cholesterol gallstone disease was 78% in concentrated gallbladder biles (biliary total lipid concentration 5 g/dl) but only 21% in dilute biles (biliary total lipid concentration <5 g/dl). In contrast, examination for the presence of cholesterol crystals in fresh bile was reasonably sensitive both in concentrated and diute gallbladder biles (sensitivity, 84% and 72%, respectively). In addition, duodenal bile obtained from 16 patients (10 cholesterol, 6 pigment) before cholecystectom showed cholesterol crystals in 7 of the cholesterol but in none of the pigment stone patients. We conclude that examination of fresh bile for cholesterol crystals is a specific and reasonably sensitive test for cholsterol gallstone disease

A geometric proof of the existence of definable Whitney stratifications

We give a geometric proof of existence of Whitney stratifications of definable sets in o-minimal structures.Comment: 9 pages, 1 figur

SOME GEOMETRIC PROPERTIES OF WHITNEY STRATIFICATIONS

We describe some old and new results about Whitney stratifications and state some open problems

Automatic methods in diagnostic bacteriology

Imperial Users onl

Exercise: it is the chill pill for stress?

Mental stress often increases our blood pressure, and makes us feel anxious, stressed and unhappy. Large increases in blood pressure and psychological responses to stress can lead to cardiovascular disease and psychological disorders. Exercise is proposed to potentially reduce these blood pressure and negative emotional responses experienced during mental stress. Forty individuals completed a 10-minute mental stress task on two separate occasions: once on its own, and once after 10-minutes of moderately high intensity cycling. Results showed blood pressure during stress was lower after exercise. However, participants also experienced greater anxiety, feelings of stress, and negative emotions such as tension and depression, during the stress following exercise. Therefore, exercise before stress may be good in reducing our blood pressure response to stress and thus reducing the risk of developing cardiovascular disease, but bad for our psychological health by causing more negative thoughts and emotions