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Biomedical subjects

B Weiss

Publications and source records attributed to B Weiss.

At least 397 records · Page 22Linked to original sources
PubMed1974

Defective interfering passages of Sindbis virus: nature of the intracellular defective viral RNA.

BHK cells infected with defective-interfering passages of Sindbis virus accumulate a species of RNA (20S) that is about half the molecular weight of the major viral mRNA (26S). We have performed competitive hybridization experiments with these species of RNA and have established that 20S RNA contains approximately 50% of the nucleotide sequences present in 26S RNA. Our further studies, however, demonstrate that 20S RNA is unable to carry out the messenger function of 26S RNA. We found very little of the defective RNA associated with polysomes in vivo. In addition, it was unable to stimulate protein synthesis in vitro under conditions in which 26S RNA was translated. We have also examined viral RNA synthesis in BHK cells infected with standard or defective-interfering passages of Sindbis virus. This comparison suggests that defective partioles do not synthesize a functional replicase.

Animals↗
PubMed1974

Behavioral assessment of lead intoxication in children.

Current questions about lead exposure focus on the consequences of levels too low to have erupted into blatantly discernible defects. The present paper addresses two sets of interrelated problems derived from this issue. One is how to define the behavioral consequences of asymptomatic lead absorption, and the second focuses on behavioral assessment procedures. Current primary prevention programs emphasize environmental monitoring, and early detection programs emphasize lead body burden measurements. The evaluation of behavioral problems in school children as a function of body burden is rarely performed. Epidemiologic data indicate sufficient natural variability to determine the degree of association between indices of total body burden and behavior. Assessment procedures are described and research suggestions offered that sample concretely defined target behaviors in social environments.

Body Burden↗
PubMed1973

Cyclic AMP phosphodiesterase in cloned astrocytoma cells: norepinephrine induces a specific enzyme form.

The soluble supernatant fraction of homogenates of cloned rat astrocytoma cells (linle C-2A) was subjected to polyacrylamide gel electrophoresis. Two peaks of adenosine 3',5'-monophosphate phosphodiesterase activity were found, corresponding to peaks I and IV of a similarly prepared homogenate of rat brain. Incubating cells with norepinephrine (0.3 mullimolar) caused about a threefold increase in the activity of peak IV but no change in peak I. This increase was completely inhibited by prior inclubation with propranolol (0.1 millimnolar), a beta-adrenergic blocking agent, or with cyclohexamnine (40 micromolar). a protein synthesis inhibitor. Induction of a specific phosphodiesterase form by norepinephrine sitggests another feedback control mechanism whereby an organism can prevent the effects of excessive sympathetic activity.

Animals↗
PubMed1973

Defective interfering passages of Sindbis virus: chemical composition, biological activity, and mode of interference.

Defective interfering (DI) particles of Sindbis virus, appearing between the eighth and fourteenth passages, cosediment with and have the same buoyant density as standard virus. Virion RNA from such late passages is heterogeneous by polyacrylamide gel electrophoresis, whereas early passage RNA is homogeneous. No differences were found in the virion proteins from such passages. Cells co-infected with early and late passage virus synthesize as much intracellular viral-specific RNA and protein as is made after infection with early passage virus alone, although virus production is inhibited by 90% or more. Such cells synthesize two new intracellular species of RNA with molecular weights of 2.2 x 10(6) and 0.86 x 10(6). Nucleocapsid assembly is blocked in these cells, and the amount of intracellular capsid protein made is reduced by 50%. The presence of a new intracellular protein in late passage infection was detected by polyacrylamide gel electrophoresis.

Animals↗