A heavily T2-weighted gradient-echo sequence was used for magnetic resonance (MR) imaging of the biliary system in five healthy volunteers and 13 patients with obstructive jaundice. Images were obtained in the sagittal and coronal planes during sequential breath-hold intervals and were post-processed by using a maximum-intensity projection algorithm. The extrahepatic and intrahepatic bile ducts were well visualized in 11 patients. The level of obstruction and the grade of dilatation were depicted with MR cholangiography. However, the cause of obstruction could be determined with MR cholangiography in only eight cases. The part of the biliary system below the obstruction could not be visualized with MR cholangiography. In the volunteers, MR cholangiography could demonstrate the anatomy of the biliary tract in only two subjects. Possible causes for this phenomenon are the limited spatial resolution of MR imaging, partial volume effects, or flow within the bile ducts. MR cholangiography may be a useful adjunctive tool for noninvasive evaluation of patients with obstructive jaundice. However, further technical advances are necessary to improve image quality.
SummaryIn serum incubated at 36° C for 18-24 hours a factor (DAS) develops which on intravenous injection into cats evokes platelet aggregation followed by an increase in pulmonary vascular resistance (PVR). This change in PVR is mediated via the platelets since it significantly correlates with the preinjection platelet count. There is evidence that phosphatidic acids (PA) and lysophosphatidic acids (LPA) are the active components of DAS. Investigations performed on platelet-rich plasma from man, cat, pig, dog, rabbit, guinea pig, and rat demonstrate that only human and feline platelets exposed to PA or to LPA are aggregated. Feline platelets are more sensitive to either compound than are the platelets from men; however, human platelets exhibit two exceptional properties, a) the sensitivity rapidly declines with time, b) pretreatment with subthreshold concentrations of LPA or PA induces a specific tachyphylaxis.
Our results show intramyocardial synthesis of pro-inflammatory cytokines in infants with congenital cardiac defects. This is associated with activation of both the NF-kappa-B and p38 MAPK pathways. The latter could be particularly important for the transduction of mechanical signals in the infant's myocardium. Synthesis of IL-10 indicates an intramyocardial anti-inflammatory potential in this age group.
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