Characterization of Markers of the Progression of Human Parvovirus B19 Infection in Virus DNA-Positive Plasma Samples.

Background: Accurate characterization of the infection stage in parvovirus B19(B19V)-positive plasma donations would help establish the donation deferral period to contribute to a safe fractionation pool of plasma.

Methods: Viral DNA load of 74 B19V DNA-positive plasma samples from whole blood donations was determined by titration using nucleic acid testing. Markers of cellular (neopterin) and humoral (B19V-specific IgM and IgG) immune response were determined by ELISA in 32 B19V DNA-positive samples and in 13 B19V DNA-negative samples.

The expression of retinoblastoma and Sp1 is increased by low concentrations of cyclin-dependent kinase inhibitors.

We examined the effect of suboptimal concentrations of cyclin-dependent kinase inhibitors, which do not interfere with cell proliferation, on retinoblastoma expression in hamster (Chinese hamster ovary K1) and human (K562 and HeLa) cells. To achieve this, we used the chemical inhibitors roscovitine and olomoucine (which inhibit CDK2 preferentially), UCN-01 (which also inhibits CDK4/6) and p21 (as an intrinsic inhibitor). All chemical inhibitors and overexpression of p21 strongly induced retinoblastoma protein expression.