Pretreatment with low-dose IL-1 has protective effects in animal models of inflammation or tissue injury, but the mechanisms of these protective effects are not established. To determine if prostaglandins are involved, we administered human recombinant IL-1ft and measured rectal PGE2 production in rabbits with formalin-immune complex colitis. (0.3 gg/kg) administered 24 h before induction of colitis increased PGE2 (231±36 to 1,299±572 pg/ml, P < 0.01) and reduced subsequent inflammatory cell infiltration index (from 2.8±03 to 1.4±0.3, P < 0.02) and edema (from 2.5±03 to 13±03, P < 0.01) compared with vehicle-matched animals. Administration of ibuprofen (10 mg/kg i.v.) together with IL-ift prevented the stimulation of PGE2 and the reduction in inflammation. Colonic PGE2 production correlated inversely with subsequent severity of inflammation (P < 0.02, r = -039) and edema (P < 0.04, r = -0.35). IL-i-administration 30 min before induction of colitis did not affect the severity of inflammation. Similarly, pretreatment with a noninflammatory synthetic peptide (fragment 163-171) of human IL-iS, either 30 min or 24 h before colitis induction, did not reduce inflammation or increase prostaglandin synthesis. These data demonstrate that pretreatment with IL-lif 24 h before the induction of colitis reduces inflammation by a mechanism that requires prostaglandin synthesis. (J. Clin. Invest. 1990. 85:582-586.) interleukin 1 -prostaglandin E2 -colitis

We consider the problem of identifying frames in a cardiac ultrasound video associated with left ventricular chamber end-systolic (ES, contraction) and end-diastolic (ED, expansion) phases of the cardiac cycle. Our procedure involves a simple application of non-negative matrix factorization (NMF) to a series of frames of a video from a single patient. Rank-2 NMF is performed to compute two end-members. The end members are shown to be close representations of the actual heart morphology at the end of each phase of the heart function. Moreover, the entire time series can be represented as a linear combination of these two end-member states thus providing a very low dimensional representation of the time dynamics of the heart. Unlike previous work, our methods do not require any electrocardiogram (ECG) information in order to select the end-diastolic frame. Results are presented for a data set of 99 patients including both healthy and diseased examples.

Analyzing and understanding the movement of the mitral valve is of vital importance in cardiology, as the treatment and prevention of several serious heart diseases depend on it. Unfortunately, large amounts of noise as well as a highly varying image quality make the automatic tracking and segmentation of the mitral valve in two-dimensional echocardiographic videos challenging. In this paper, we present a fully automatic and unsupervised method for segmentation of the mitral valve in two-dimensional echocardiographic videos, independently of the echocardiographic view. We propose a bias-free variant of the robust non-negative matrix factorization (RNMF) along with a window-based localization approach, that is able to identify the mitral valve in several challenging situations. We improve the average f1-score on our dataset of 10 echocardiographic videos by 0.18 to a f1-score of 0.56.

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