The superoxide dismutase inhibitor diethyldithiocarbamate has antagonistic effects on apoptosis by triggering both cytochrome c release and caspase inhibition.

Tumor necrosis factor-alpha (TNF-alpha) and etoposide both trigger a large and rapid production of reactive oxygen species (ROS) in HeLa cells. This occurs before translocations of the proapoptotic Bax and cytochrome c proteins, the loss of mitochondrial membrane potential (DeltaPsim), and apoptosis. We have used diethyldithiocarbamate (DDC), a well-known inhibitor of Cu, Zn superoxide dismutase to study the role of ROS in this system.

Caspase-9 can antagonize p53-induced apoptosis by generating a p76(Rb) truncated form of Rb.

The tumor suppressor Rb (retinoblastoma protein) is known to regulate p53-dependent apoptosis, but the mechanisms involved are unclear. In a rat fibroblast model, we previously observed that caspase inhibition potentiates p53-dependent apoptosis and prevents the Rb cleavage associated with p53 activation. These results suggested that a caspase(s) can antagonize p53-mediated apoptosis via the production of a protective Rb truncated form.

Bcl-2 can promote p53-dependent senescence versus apoptosis without affecting the G1/S transition.

With the aim to identify events involved in the determination of p53-dependent apoptosis versus growth arrest, we used rat embryo fibroblasts expressing a temperature-sensitive mutant (tsA58) of the SV40 large tumour antigen (LT). Heat-inactivation of LT leads to p53 activation and commitment to a senescent-like state (REtsA15 cell line) or apoptosis (REtsAF cell line). We report that senescence is associated with high levels of the anti-apoptotic Bcl-2 protein and a cell cycle arrest in G1 phase, whereas apoptosis is associated with low levels of Bcl-2 and a cell cycle arrest in G2 phase.

[A joint continuing medical education program for practitioners and radiologists: a positive preliminary experience].

Purpose: A common reflective continuing medical education (CME) approach has been promoted by the French National CME Association (UNAFORMEC) and French Radiologic Organizations to improve imaging prescriptions performed by general practitioners (GP) as well as their relationships with radiologists to fit the best decision resources for an optimal patient care. This new practice based CME is a multidisciplinary learning model.

Materials And Methods: A learning model that could satisfy GP and favor improved communication between them and radiologists was elaborated.

Aeromonas hydrophila adenylyl cyclase 2: a new class of adenylyl cyclases with thermophilic properties and sequence similarities to proteins from hyperthermophilic archaebacteria.

Complementation of an Escherichia coli cya mutant with a genomic library from Aeromonas hydrophila allowed isolation of clones containing two different cya genes. Whereas one of these genes (cyaA) coded for an adenylyl cyclase (AC1) belonging to the previously described class I adenylyl cyclases (ACs), the second one (cyaB) coded for a protein (AC2) that did not match any previously characterized protein when compared to protein sequence databases. In particular, it did not align with any of members of the three known classes of ACs.