Dorothy R. Tovell

Observations on the assay of infectious viral ribonucleic acid: Effects of DMSO and DEAE-dextran☆

Abstract DMSO and DEAE-D have been shown to stimulate the formation of infectious centers when added to media in which L cells and Mengo RNA are incubated. Maximum stimulation is obtained with DMSO when the compound is present at a concentration of 10–12.5% in the basic medium, 0.6 M sucrose/PBS, while DEAE-D is maximally effective at a concentration of 100 μg/ml in PBS. The latter is, by a wide margin, the most efficient medium for assaying the infectivity of Mengo RNA by the infectious center method. The stimulating effects of DMSO and DEAE-1) are not additive. The kinetics of infectious center formation in 0.6 M sucrose/PBS-10% DMSO and PBS containing 100 μg DEAE-D/ml have been studied, and the optimal time of incubation in the two media has been found to be 6 minutes and 2–3 minutes, respectively. Evidence is presented to support the premise that, in the suspended cell assay of viral RNA at least, only a very small percentage of the potentially infectious RNA molecules are detected.

Interferon production by lymphocytes from multiple sclerosis and non‐MS patients

Peripheral blood lymphocytes from MS patients and non-MS patients were induced to produce interferon by incubation with canine distemper, mumps, Sendai, herpes simplex I, and two strains of measles viruses. Lymphocytes from MS patients produced as much pH 2 stable interferon as did those from non-MS patients in response to induction with any of these viruses. In addition, there were no significant differences in amounts of interferon produced by lymphocytes from MS patients in three different clinical stages of the disease.

The interaction of tritium-labelled Mengo virus RNA and L cells: The effects of DMSO and DEAE-dextran☆

Abstract DMSO and DEAE-D have been shown to stimulate the formation of infectious centers when added to media in which L cells and Mengo RNA are incubated. As part of a continuing investigation of the effects of these additives on cell-RNA interaction, their effects on the uptake of 3 H-labelled viral RNA by L cells were examined. Viral RNA was isolated by a modified phenol technique from highly purified Mengo virus which had been propagated in L cells in the presence of actinomycin D and uridine- 3 H. The uptake of radiolabel by L cells was measured after their incubation with 3 H-labelled viral RNA in PBS, in 0.6 M sucrose/PBS, in 0.6 M sucrose/PBS-10% DMSO, and in PBS containing 100 μg DEAE-D per milliliter. Extremely small quantities of RNA are taken up by cells incubated in 0.6 M sucrose/PBS, and the uptake is not increased by the presence of DMSO in the incubation medium. More RNA is taken up by cells incubated in PBS than by cells incubated in either of the sucrose media examined, and the presence of DEAE-D in the medium produces a striking increase in the amount of RNA that becomes firmly cell associated. Most of the RNA that becomes cell associated during incubation in PBS and the two sucrose media remains so after incubation of the cells with pancreatic ribonuclease, whereas approximately 90% of the RNA that is bound to cells in the presence of DEAE-D is removed by a brief exposure to this enzyme.

Chapter 13 – Transitions

As women progress through careers in the sciences, they encounter many changes. Changes are external, but they require the internal process of transition. William Bridges defines transition as the psychological process people go through to come to terms with a new situation. We share the stories of women in the sciences who have navigated these transitions including during their education and move into the workforce, during changes in their career, after 10 years in the workforce, and from one type of lifestyle to another, and explore the factors which have allowed them to be successful.

Synthesis and biological properties of (E)-5-(2-[82Br]bromovinyl)-1-(2-deoxy-2-fluoro-β-d-ribofuranosyl)uracil ([82Br]BVFRU)

Abstract (E)-5-(2-Bromovinyl)-1-(2-deoxy-2-fluoro-β- d -ribofuranosyl)uracil (BVFRU) was synthesized in 24% yield by reacting (E)-5-(2-carboxyvinyl)-1-(2-deoxy-2-fluoro-β- d -ribofuranosyl)uracil (CVFRU) with NH4Br in the presence of chloramine-T. [82Br]BVFRU was prepared in 14.5% radiochemical yield, with a specific activity of 58 MBq mmol-1, by a similar reaction of CVFRU with ammonium [82Br]bromide. BVFRU is equipotent to iodovinyldeoxyuridine (IVDU) and iodovinyl-2′-fluorodeoxyuridine (IVFRU) (MIC50 = 0.1–0.01 μ g mL-1) against herpes simplex virus which encodes for thymidine kinase (HSV-1 TK+), and has a partition coefficient similar to that of IVDU and IVFRU (log P = 0.72 vs 1.6 and 1.21, respectively). BVFRU has an inhibition constant (Ki) of 0.044 for the nitrobenzylthioinosine (NBMPR)-sensitive transport of thymidine across the murine erythrocyte membrane. These data suggest that BVFRU is similar to BVDU in antiviral potency and transport characteristics; it is proposed that ease of synthesis and resistance to metabolic degradation make radiolabelled BVFRU a superior candidate for in vivo diagnostic studies of HSE.