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S Panem

Publications and source records attributed to S Panem.

44 records · Page 3Linked to original sources
PubMed1974

Cell-cycle dependent appearance of murine leukemia-sarcoma virus antigens.

Normal rat kidney (NRK) cells, NRK cells infected with Rauscher murine leukemia virus, and NRK cells infected with Kirsten murine sarcoma-leukemia virus (NRK-K) were synchronized by a double thymidine block. At intervals after release from thymidine blockage, the cells were examined for the presence of viral antigens in the cytoplasm and on the cell surface by immunofluorescent microscopy by using goat anti-Rauscher murine leukemia virus and goat anti-Moloney leukemia virus (Tween-ether disrupted) sera. Detection of viral antigens in the cytoplasm was periodic during the cell cycle. Antigens were detected first during the S phase, increased during the G2 phase, and disappeared during the M and G1 phases. A similar pattern of surface immunofluorescence was observed. Infectious virus was detected in culture fluids from synchronized cells during the M phase. Surface immunofluorescence was detected in NRK-K cells with anti-Rauscher murine leukemia virus and may represent the presence of group-specific antigens on the cell surface. Control, uninfected NRK cells, which did not normally fluoresce, showed weak immunofluorescence during the S and G2 phases after synchronization. Synchronization can be used to amplify latent oncornavirus expression.

Animals↗
PubMedDate not supplied

Regulation and evolving science: neurobehavioral toxicology.

A number of policy and scientific issues are associated with the introduction of emerging or non-traditional scientific disciplines into the governmental regulatory apparatus. The present discussion derives from the issue of the extent of toxicological testing required for the evaluation of the health and safety aspects of pesticides and other compounds at the Environmental Protection Agency. The area of neurobehavioral toxicology is used as a case study for the introduction of a new biological endpoint into the regulatory arena. In that context, this paper addresses the following policy/regulatory issues: why expand the endpoints for toxicity testing from those currently in use; what is the current regulatory situation; what are the alternative means by which a new endpoint could be incorporated into the regulatory process; what would be the consequences of requiring examination of new endpoints? In the process of evaluating those issues, scientific issues involved with the selection of test systems are discussed. They include the selection of particular tests, the testing strategy, and the validity, reliability and sensitivity of the tests.

Animals↗