A new heparin fragment decreases liver ischemia-reperfusion injury

<正>To the Editor:Ischemia-reperfusion injury following surgery and transplantation can lead to irreversible multiorgan failure.Intracellular calcium overload is associated to cellular death during ischemiareperfusion.A recently discovered heparin fragment (HF),trisulfated disaccharide (TD),that acts on sodium-calcium exchanger(NCX) decreasing intracellular Ca²⁺,showed effectiveness on protecting hepatocytes from ischemia-reperfusion injury [1],     

Multiphasic MR imaging: a new method for direct imaging of pulsatile CSF flow

A new technique is described that allows for the creation of pure pulsatile flow magnetic resonance (MR) images in a single acquisition. Five to 16 electrocardiographically gated images spanning the entire cardiac cycle are obtained with use of a gradient-echo pulse sequence. The section can be varied from 4 mm thick to full thickness projection. Taken singly, each image provides direct assessment of flow direction and velocity. Subtraction of image pairs eliminates signal detected from stationary protons, producing images of pulsatile flow. In this study the technique was used to image the flow of cerebrospinal fluid (CSF) in healthy subjects and in one patient with syringohydromyelia. The data suggest that multiphasic MR imaging provides a powerful means for the noninvasive assessment of CSF pulsatile flow dynamics and may have potential clinical application for the investigation of a variety of abnormalities such as normal pressure hydrocephalus, syrinx, and spinal block.     

MR gated subtraction angiography: evaluation of lower extremities

We report the first clinical experience with a new method for projective imaging of blood vessels (angiography) using magnetic resonance. Vascular contrast is produced noninvasively by the phase response of moving protons. Diastolic and systolic gated images produce, respectively, flow signal and flow void; the difference image is a map of the pulsatile flow: an arteriogram. Preliminary studies are presented of the lower extremities of one healthy volunteer and four patients (one each with occlusive disease, soft-tissue tumor, arteriovenous malformation, and venous femoral-popliteal graft). Patient data are compared with accompanying conventional arteriograms, and the new method is discussed.     

Quantification of blood flow with dynamic MR imaging and presaturation bolus tracking

A technique is described for rapid imaging of blood flow and dynamic measurement of its velocity. The method is a combination of bolus tracking and low-flip-angle gradient-echo cine angiography. This method provides precise determination of velocity with high temporal resolution in a single measurement. Unlike what occurs in phase imaging techniques, flow is displayed directly, eliminating potential errors that result from non-flow-related sources of phase shifts. Manipulation of raw data sets is avoided. Results obtained from a flow phantom, healthy volunteers, and a patient with an aortic aneurysm demonstrate the capability of the technique to track flow at low and high velocities and to differentiate flowing blood from thrombus. Because of its conceptual simplicity, rapidity, and lack of susceptibility to extraneous phase shifts, this technique may prove ideal for in vivo flow measurement and evaluation of flow patterns.