Atherosclerosis impairs endothelium-dependent relaxation of large conduit arteries. Because coronary resistance vessels are spared from the development of overt atherosclerosis, endothelium-dependent responses were examined in these vascular segments. Malaysian cynomolgus monkeys (n = 6) were made atherosclerotic by being fed a 0.7% cholesterol diet for 18 months. Control monkeys (n = 6) were fed a standard diet. Coronary microvessels (122-220 microns) were studied in a pressurized (20 mm Hg), no-flow state using a video-imaging apparatus. Relaxations of microvessels, preconstricted with the thromboxane analogue U46619, were determined in response to acetylcholine, bradykinin, the calcium ionophore A23187, adenosine, and sodium nitroprusside. Microvascular relaxations to bradykinin and A23187 were reduced in atherosclerotic monkeys compared with controls, whereas acetylcholine produced additional contraction in atherosclerotic monkeys. Responses of preconstricted microvessels to adenosine and sodium nitroprusside were identical in atherosclerotic and control animals. Indomethacin did not alter responses in control or atherosclerotic animals. Histologic examination revealed neither intimal thickening nor plaque formation in microvessels of this size class despite marked changes in conduit arteries. Electron microscopy showed minor alterations of endothelial cell morphology in microvessels of atherosclerotic animals. In conclusion, long-term hypercholesterolemia markedly impairs endothelium-dependent vascular relaxation in the coronary microcirculation where overt atherosclerosis does not develop. These changes in endothelial cell function may significantly alter regulation of myocardial perfusion by neurohumoral stimuli.
471 ovarian tumours were available for study from 1980 to 1987. Epidemiological breakdown by race, age and the histological type of the tumours was obtained. The diagnosis of the individual tumours was based on the World Health Organisation (WHO) histological classification of ovarian tumours. There were 324 (68.8%) benigh and 147 (31.2%) malignant tumours. 253 (53.7%) of the tumours were seen in the Malays. The third decade was the peak age for the benigh tumours, and for the malignant tumours, the fourth and fifth decades. 138 (42.6%) of the benign ovarian tumours were cystic teratomas and 45 (30.6%) of the malignant tumours were cystadenocarcinoma.
A retrospective analysis of 49 patients with 55 liver abscesses evaluated by diagnostic ultrasonography was made. The sonographic appearances were varied and non-specific. 96% of the abscesses were in the right lobe of the liver. Sonographic features which were frequently observed include (a) predominantly hypoechoic internal echotexture (64%) (b) distal sonic enhancement (98%) (c) well-defined margin with an abrupt transition between normal liver parenchyma and lesion (96%) and (d) absence of wall echoes (89%). A combination of these features has considerable diagnostic value. Distal sonic enhancement is of particular diagnostic importance. In equivocal cases the diagnosis can be quickly determined by percutaneous needle aspiration under ultrasound guidance.
Stool samples obtained from 120 Malay children, aged below 6 years, in Mukim Ijok, Kuala Selangor, were tested. Enteric pathogens were found in 7.5% of specimens. Enteropathogenic Escherichia coli (EPEC) was the most common enteric pathogen isolated (6.7%) followed by Salmonella spp (0.83%). The rate of isolation was independent of age and sex.
MeSH terms: Aged; Child; Escherichia coli; Malaysia; Salmonella; Sex