A New Mechanism for Hydroxyl Radical Production in Irradiated Nanoparticle Solutions

The absolute yield of hydroxyl radicals per unit of deposited X‐ray energy is determined for the first time for irradiated aqueous solutions containing metal nanoparticles based on a “reference” protocol. Measurements are made as a function of dose rate and nanoparticle concentration. Possible mechanisms for hydroxyl radical production are considered in turn: energy deposition in the nanoparticles followed by its transport into the surrounding environment is unable to account for observed yield whereas energy deposition in the water followed by a catalytic‐like reaction at the water‐nanoparticle interface can account for the total yield and its dependence on dose rate and nanoparticle concentration. This finding is important because current models used to account for nanoparticle enhancement to radiobiological damage only consider the primary interaction with the nanoparticle, not with the surrounding media. Nothing about the new mechanism appears to be specific to gold, the main requirements being the formation of a structured water layer in the vicinity of the nanoparticle possibly through the interaction of its charge and the water dipoles. The massive hydroxyl radical production is relevant to a number of application fields, particularly nanomedicine since the hydroxyl radical is responsible for the majority of radiation‐induced DNA damage.     

Functional properties of a new line of immortalized human endothelial cells

An immortalized human endothelial cell line was obtained by transfecting umbilical vein endothelial cells in primary culture with plasmid pMK16 containing SV40 replicated origin defective gene. The essential functional properties demonstrated in these immortalized human endothelial cells also retaining the classical phenotypical characteristics of endothelial cells in primary culture are: (1) endothelin-1 secretion; (2) capacity to convert big endothelin-1 into endothelin-1; (3) the capacity to secrete IL1 beta and IL6 interleukins both spontaneously and after lipopolysaccharide (LPS) stimulation; (4) arginine transfer from the extracellular to the intracellular medium. Such stable cell line could facilitate studies of regulation of endothelin-1 production; (5) No-synthase activity; (6) binding and metabolisation of acetylated low-density lipoproteins.     

Poisoning by anorexigenics. Information from the data bank of the Anti-Poison Center of Marseille (1973)

Using the data bank developed by the Computer Service of the Lyon Hospitals, the Anti-Poisons Centre of Marseille presents an initial study of intoxications by appetite suppressants. The work was complemented by a simultaneous study using conventional manual techniques. An epidemiologic review of 1973 and an approximate assessment of toxic doses in the adult and child were possible. They should be of particular use in answering telephone enquiries at anti-poison centres.     

Structure et proprietes physiques des phases Cu2TlX2, Cu3 YTl2X4 (AVEC X = Se,Te et Y = Fe,Ga, Al)

Ternary (Cu₂TlX₂) and quarternary (Cu₃YTl₂X₄) compounds (with X = Se, Te and Y = Fe, Ga, Al) have been prepared and characterized. All of them have the same lamellar structure where tetrahedras (CuYX₄)_n and thallium atoms in coordination eight form successive layers. Some are metallic conductors (Cu₂TlX₂) whereas others are semi-conductors (Cu₃YTlX₄). The metallic behaviour could be due to thallium monovalent-thallium trivalent interactions within the layers.     

African swine fever virus gene A179L, a viral homologue of bcl-2, protects cells from programmed cell death

The African swine fever virus (ASFV) open reading frame A179L, which is similar to the human proto-oncogene bcl-2, has been cloned and expressed in vaccinia virus under control of the pEIL synthetic early/late promoter. The A179L gene product prevented cell death in HeLa and BSC-40 cells doubly infected with another recombinant vaccinia virus expressing the interferon-induced double-stranded RNA-activated protein kinase (p68 kinase), which activates a rapid cell death characteristic of apoptosis. This finding suggests that the A179L gene has a function similar to that of bcl-2 in preventing apoptosis and may play an important role during productive ASFV infection.