Enhancing and expansile portal vein thrombosis: value in the diagnosis of hepatocellular carcinoma in patients with multiple hepatic lesions

OBJECTIVE: The objective of this study was to determine whether the presence of enhancing and expansile portal vein thrombus is suggestive of the diagnosis of hepatocellular carcinoma. CONCLUSION: In the presence of hepatic tumors, enhancing expansile portal vein thrombus is highly suggestive of hepatocellular carcinoma.     

Cross-sectional imaging in acute pancreatitis

Acute pancreatitis is a common disease with potentially serious outcomes. Multiple imaging modalities can be used to evaluate the disease process and its associated complications. Familiarity with the pathogenesis of this disease, indications for imaging, imaging protocols, staging systems, and the strengths and weaknesses of various modalities will help the radiologist optimize patient care.     

Roles for mitochondria in pentamidine susceptibility and resistance in Leishmania donovani

Pentamidine resistant Leishmania donovani was raised in the laboratory by stepwise exposure to increasing drug pressure until a line capable of growth in 8 microM pentamidine (R8) had been selected. An IC(50) value of 40 microM was determined for this line, some 50-fold higher than that recorded for the parental wild-type line. The pentamidine resistant promastigotes were cross-resistant to other toxic diamidine derivatives but not to antimonials or substrates of multidrug resistance pumps. Decreased mitochondrial transmembrane potential was observed in pentamidine resistant promastigotes. A substantial net decrease in accumulation of [(3)H]-pentamidine accompanied the resistance phenotype. Inhibitors of P-glycoprotein pumps, including prochlorperazine and trifluoperazine, did not reverse this decreased drug uptake, which distinguishes the L. donovani resistant line studied here from L. mexicana promastigotes previously studied for pentamidine resistance. Kinetic analysis identified a carrier with an apparent K(m) value of 6 microM for pentamidine. No significant difference between wild-type and resistant parasites could be detected with respect to this transporter in rapid uptake experiments. However, in longer-term uptake experiments and also using concentrations of pentamidine up to 1mM, it was demonstrated that wild-type cells, but not resistant cells, could continue to accumulate pentamidine after apparent saturation via the measured transporter had been reached. Agents that diminish the mitochondrial membrane potential inhibited this secondary route. A fluorescent analogue of pentamidine, 2,5-bis-(4-amidophenyl)-3,4-dimethylfuran (DB99), accumulated in the kinetoplast of wild-type but not resistant parasites indicating that uptake of this cationic compound into mitochondria of wild-type cells was more pronounced than in the resistant line. These data together indicate that resistance to pentamidine in L. donovani is associated with alterations to the mitochondria of the parasites, which lead to reduced accumulation of drug.