Student peer assessment in evidence-based medicine (EBM) searching skills training: an experiment.

BACKGROUND: Student peer assessment (SPA) has been used intermittently in medical education for more than four decades, particularly in connection with skills training. SPA generally has not been rigorously tested, so medical educators have limited evidence about SPA effectiveness. EXPERIMENTAL DESIGN: Seventy-one first-year medical students were stratified by previous test scores into problem-based learning tutorial groups, and then these assigned groups were randomized further into intervention and control groups. All students received evidence-based medicine (EBM) training. Only the intervention group members received SPA training, practice with assessment rubrics, and then application of anonymous SPA to assignments submitted by other members of the intervention group. RESULTS: Students in the intervention group had higher mean scores on the formative test with a potential maximum score of 49 points than did students in the control group, 45.7 and 43.5, respectively (P = 0.06). CONCLUSIONS: SPA training and the application of these skills by the intervention group resulted in higher scores on formative tests compared to those in the control group, a difference approaching statistical significance. The extra effort expended by librarians, other personnel, and medical students must be factored into the decision to use SPA in any specific educational context. IMPLICATIONS: SPA has not been rigorously tested, particularly in medical education. Future, similarly rigorous studies could further validate use of SPA so that librarians can optimally make use of limited contact time for information skills training in medical school curricula.

Cationic phenylene ethynylene polymers and oligomers exhibit efficient antiviral activity.

The antiviral activities of poly(phenylene ethynylene) (PPE)-based cationic conjugated polyelectrolytes (CPE) and oligo-phenylene ethynylenes (OPE) were investigated using two model viruses, the T4 and MS2 bacteriophages. Under UV/visible light irradiation, significant antiviral activity was observed for all of the CPEs and OPEs; without irradiation, most of these compounds exhibited high inactivation activity against the MS2 phage and moderate inactivation ability against the T4 phage. Transmission electron microscopy (TEM) and SDS polyacrylamide gel electrophoresis (SDS-PAGE) reveal that the CPEs and OPEs exert their antiviral activity by partial disassembly of the phage particle structure in the dark and photochemical damage of the phage capsid protein under UV/visible light irradiation.

Heat shock protein 70 and glycoprotein 96 are differentially expressed on the surface of malignant and nonmalignant breast cells.

Heat shock proteins (HSPs), which are important for a number of different intracellular functions, are occasionally found on the surface of cells. The function of heat shock protein on the cell surface is not understood, although it has been shown to be greater in some tumor cells and some virally infected cells. Surface expression of both glycoprotein 96 (gp96) and Hsp70 occurs on tumor cells, and this expression correlates with natural killer cell killing of the cells. We examined the surface expression of gp96 and Hsp70 on human breast cell lines MCF7, MCF10A, AU565, and HS578, and in primary human mammary epithelial cells by immunofluorescence microscopy and flow cytometry. The nonmalignant cell lines HS578, MCF10A, and HMEC showed no surface expression of gp96, whereas malignant cell lines MCF7 and AU565 were positive for gp96 surface expression. All of the breast cell lines examined showed Hsp70 surface expression. These results also confirm previous studies, demonstrating that Hsp70 is on the plasma membrane of tumor cell lines. Given the involvement of heat shock proteins, gp96 and Hsp70, in innate and adaptive immunity, these observations may be important in the immune response to tumor cells.

Nuclear poly(A)-binding protein PABPN1 is associated with RNA polymerase II during transcription and accompanies the released transcript to the nuclear pore.

The nuclear poly(A)-binding protein, PABPN1, has been previously shown to regulate mRNA poly(A) tail length and to interact with selected proteins involved in mRNA synthesis and trafficking. To further understand the role of PABPN1 in mRNA metabolism, we used cryo-immunoelectron microscopy to determine the fate of PABPN1 at various stages in the assembly and transport of the Chironomus tentans salivary gland Balbiani ring (BR) mRNA ribonucleoprotein (mRNP) complex. PABPN1 is found on BR mRNPs within the nucleoplasm as well as on mRNPs docked at the nuclear pore. Very little PABPN1 is detected on the cytoplasmic side of the nuclear envelope, suggesting that PABPN1 is displaced from mRNPs during or shortly after passage through the nuclear pore. Surprisingly, we also find PABPN1 associated with RNA polymerase II along the chromatin axis of the BR gene. Our results suggest that PABPN1 binds to the polymerase before, at, or shortly after the start of transcription, and that the assembly of PABPN1 onto the poly(A) tail may be coupled to transcription. Furthermore, PABPN1 remains associated with the released BR mRNP until the mRNP is translocated from the nucleus to the cytoplasm.