Analysis of the 1957-58 Soviet nuclear accident

The occurrence of a Soviet accident in the winter of 1957-58, involving the atmospheric release of reprocessed fission wastes (cooling time approximately 1-2 yrs.), appears to have been confirmed, primarily by an analysis of the USSR radioecology literature. Due to the high population density in the affected region (Cheliabinsk Province in the highly industrialized Urals Region) and the reported level of /sup 90/Sr contamination , the event probably resulted in the evacuation and/or resettlement of the human population from a significant area (100-1000 km/sup 2/). The resulting contamination zone is estimated to have contained approximately 10/sup 6/ Ci of /sup 90/Sr (reference radionuclide); a relatively small fraction of the total may have been dispersed as an aerosol. Although a plausible explanation for the incident exists (i.e., use of now-obsolete waste storage-/sup 137/Cs isotope separation techniques), it is not yet possible, based on the limited information presently available, to completely dismiss this phenomenon as a purely historical event. It seems imperative that we have a complete explanation of the causes and consequences of this incident. Soviet experience gained in application of corrective measures would be invaluable to the rest of the world nuclear community

Senescence-Induced Alterations of Laminin Chain Expression Modulate Tumorigenicity of Prostate Cancer Cells

Prostate cancer is an age-associated epithelial cancer, and as such, it contributes significantly to the mortality of the elderly. Senescence is one possible mechanism by which the body defends itself against various epithelial cancers. Senescent cells alter the microenvironment, in part, through changes to the extracellular matrix. Laminins (LMs) are extracellular proteins important to both the structure and function of the microenvironment. Overexpression of the senescence-associated gene mac25 in human prostate cancer cells resulted in increased mRNA levels of the LM α4 and β2 chains compared to empty vector control cells. The purpose of this study was to examine the effects of these senescence-induced LM chains on tumorigenicity of prostate cancer cells. We created stable M12 human prostate cancer lines overexpressing either the LM α4 or β2 chain or both chains. Increased expression of either the LM α4 or β2 chain resulted in increased in vitro migration and in vivo tumorigenicity of those cells, whereas high expression of both chains led to decreased in vitro proliferation and in vivo tumorigenicity compared to M12 control cells. This study demonstrates that senescent prostate epithelial cells can alter the microenvironment and that these changes modulate progression of prostate cancer

Local synthesis of axonal and presynaptic RNA in squid model systems

The presence of active systems of protein synthesis in axons and nerve endings raises the question of the cellular origin of the corresponding RNAs. Our present experiments demonstrate that, besides a possible derivation from neuronal cell bodies, axoplasmic RNAs originate in periaxonal glial cells and presynaptic RNAs derive from nearby cells, presumably glial cells. Indeed, in perfused squid giant axons, delivery of newly synthesized RNA to the axon perfusate is strongly stimulated by axonal depolarization or agonists of glial glutamate and acetylcholine receptors. Likewise, incubation of squid optic lobe slices with