Fludarabine-induced apoptosis in CD19+/CD5+B-CLL cells is a direct and nurse-like-cell independent effect

B-cell chronic lymphocytic leukemia (B-CLL) is a hematological malignancy characterized by the accumulation of mature CD5+ B lymphocytes with a defective apoptosis. A subset of blood monocyte-derived adherent cells generated in vitro protects B-CLL cells from apoptosis playing a role as nurse-like cells (NLCs). Fludarabine (9-beta-D-arabinofuranosyl-2-fluoroadenine; F-ara-A) is an adenine nucleoside analog used to treat B-CLL. To gain insight into the mechanisms implicated in the antitumoral effect of fludarabine in B-CLL cells, we performed cross-cultures with B-CLL cells and NLCs treated and untreated with fludarabine. Our results showed that fludarabine blocked the development of NLCs and induced apoptosis in these cells when they were present in culture. Moreover, CD19+/CD5+B-CLL cells treated with fludarabine underwent apoptosis and this event was not related with the presence of NLCs whether treated or not with fludarabine. In conclusion, apoptosis induced by fludarabine in CD19+/CD5+B-CLL cells was due to a direct effect on these cells and not due to its effect in the NLCs.     

Characterization of coloured compounds obtained by enzymatic extraction of bakery products.

Melanoidins, the brown-colored polymers formed through Maillard type reaction in several heat-treated foods, represent a significant part of our diet, with an average intake of grams per day. Most of the studies on the physiological effects of these compounds have been performed using the water soluble melanoidin fractions. But dietary melanoidins formed on the surface of bakery products are poorly soluble in water as well as in organic solvents. In this work, an enzymatic solubilization procedure was developed on a gluten-glucose model system and it was applied to bread and biscuits. The soluble material obtained was tested for its antioxidant activity, for its effect on phase-I and phase-II xenobiotic enzymes and for potential cytotoxic effects. Soluble melanoidins from model system and biscuits exhibit a strong antioxidant activity and do not show any cytotoxicity on Caco-2 cells. Melanoidins extracted from biscuits was able to inhibit the activity of Phase I (NADPH-cytochrome-c reductase) and Phase II (Glutathione-S-transferase) enzymes, whereas the low molecular weight melanoidins isolated from gluten-glucose model system inhibit the activity of NADPH-cytochrome-c reductase.     

Non-invasive in vivo imaging of myocardial apoptosis and necrosis

Myocardial necrosis plays an important role in the pathogenesis of various cardiovascular disorders and can result from different myocardial insults. Its non-invasive identification and localisation therefore may help in the diagnosis of these disorders, as well as in prognosis and assessment of treatment response. Apoptosis, or programmed cell death, is important in the spectrum of myocardial damage since it is gradually becoming more apparent that cell death may begin as apoptosis and not as necrosis. First attempts to directly visualise the area of myocardial necrosis were based on recognition of myocardial infarction with "hot spot imaging agents" in patients with chest pain. Since then, the study of myocardial necrosis with gamma imaging agents has gone beyond the detection of myocardial infarction, and attempts have been made to diagnose other cardiovascular disorders associated with cardiac cell death such as heart transplant rejection, myocarditis, cardiotoxicity and cardiomyopathies. Traditionally, two hot spot imaging agents have been used for the detection of myocardial necrosis, (99m)Tc-pyrophosphate and (111)In-antimyosin. In addition, preliminary studies have demonstrated promising results with (99m)Tc-glucarate. Recently, (99m)Tc-annexin V has been successfully used for non-invasive gamma imaging of apoptosis after acute myocardial infarction, acute myocardial ischaemia, acute cardiac allograft rejection and malignant intracardiac tumours. This review article focusses on the characteristics of these different myocardial necrotic and apoptotic markers and compares their role in the assessment of myocardial damage.     

Permissiveness of human biliary epithelial cells to infection by hepatitis C virus

The cellular tropism of hepatitis C virus (HCV) is an important but much debated issue. Permissivity to HCV of biliary cells has never been demonstrated. In this context, we used gallbladder epithelial cells (GBEC) as a model of the more proximal biliary epithelium. These cells were isolated from HCV-positive and -negative individuals and cultured for up to 40 days. Biliary cells from HCV-negative subjects were infected in vitro with various inocula. The retention of GBEC functional characteristics was assessed by the expression of cystic fibrosis transmembrane conductance regulator (CFTR). All 12 GBEC tested from HCV-negative patients were successfully infected by HCV. This was assessed by: 1) the detection of HCV-RNA positive and negative strands; 2) the detection of the viral capsid by immunofluorescence; and 3) the combination of single-strand conformation polymorphism (SSCP) and HVR1 sequence analysis demonstrating the distinct majoritary HCV genomes in serum and in GBEC. The level of HCV RNA in cell extracts and supernatants was low, but HCV infection was highly reproducible. Our results expand those showing the cellular tropism of HCV, and demonstrate the sensitivity of biliary cells to HCV infection. This might have an important impact in terms of pathogenesis and pathological features of HCV infection. In addition, given the easy access to these cells and the high reproducibility of in vitro infection, they should constitute an important tool for studies aimed at analyzing the issue of HCV penetration and neutralizing antibodies.