Problem-Based Learning Could Tackle the Issue of Insufficient Education and Adherence in People Living With HIV/AIDS.

Poor medication adherence is still the main cause of antiretroviral therapy (ART) failure among people living with HIV/AIDS (PLWHA). Effective behavioral interventions are needed to improve HIV awareness and medication adherence. In this retrospective cohort study, we assessed the effect of problem-based learning (PBL) approaches to HIV-related education and adherence outcomes among PLWHA and a college student sample.

Modelling the Epidemiological Impact and Cost-Effectiveness of PrEP for HIV Transmission in MSM in China.

Risk of HIV infection is high in Chinese MSM, with an annual HIV incidence ranging from 3.41 to 13.7/100 person-years.

A structural basis for the allosteric regulation of non-hydrolysing UDP-GlcNAc 2-epimerases.

The non-hydrolysing bacterial UDP-N-acetylglucosamine 2-epimerase (UDP-GlcNAc 2-epimerase) catalyses the conversion of UDP-GlcNAc into UDP-N-acetylmannosamine, an intermediate in the biosynthesis of several cell-surface polysaccharides. This enzyme is allosterically regulated by its substrate UDP-GlcNAc. The structure of the ternary complex between the Bacillus anthracis UDP-GlcNAc 2-epimerase, its substrate UDP-GlcNAc and the reaction intermediate UDP, showed direct interactions between UDP and its substrate, and between the complex and highly conserved enzyme residues, identifying the allosteric site of the enzyme.

Telomerase activation in mouse mammary tumors: lack of detectable telomere shortening and evidence for regulation of telomerase RNA with cell proliferation.

Activation of telomerase in human cancers is thought to be necessary to overcome the progressive loss of telomeric DNA that accompanies proliferation of normal somatic cells. According to this model, telomerase provides a growth advantage to cells in which extensive terminal sequence loss threatens viability. To test these ideas, we have examined telomere dynamics and telomerase activation during mammary tumorigenesis in mice carrying a mouse mammary tumor virus long terminal repeat-driven Wnt-1 transgene.

The binding site of karyopherin alpha for karyopherin beta overlaps with a nuclear localization sequence.

By using proteolysis, recombinant mutant proteins, or synthetic peptides and by testing these reagents in liquid phase binding or nuclear import assays, we have mapped binding regions of karyopherin alpha. We found that the C-terminal region of karyopherin alpha recognizes the nuclear localization sequence (NLS), whereas its N-terminal region binds karyopherin beta. Surprisingly, karyopherin alpha also contains an NLS.

Cell-free conversion of a ubiquitous nuclear protein into a killer-cell-specific form that binds to the NF-P enhancer element of the mouse perforin gene.

Two nuclear factors, designated NF-PI and NF-P2, have been shown to bind to an enhancer 9-base motif (5'-ACAGGAAGT-3', NF-P motif) present within the 5'-flanking region of the mouse perforin gene. Our previous studies have shown that, although NF-P1 and NF-P2 differ in cell-type distribution and molecular mass, with NF-P2 being killer-cell-specific and smaller, the two factors appear to share common DNA-binding subunit(s). We have postulated that the biochemical event involved in the induction of NF-P2 could be the dissociation of a non-DNA-binding subunit from NF-P1, rendering the newly formed NF-P2 transcriptionally active.

Heterogeneity of primer extension products in asymmetric PCR is due both to cleavage by a structure-specific exo/endonuclease activity of DNA polymerases and to premature stops.

In PCR, DNA polymerases from thermophilic bacteria catalyze the extension of primers annealed to templates as well as the structure-specific cleavage of the products of primer extension. Here we show that cleavage by Thermus aquaticus and Thermus thermophilus DNA polymerases can be precise and substantial: it occurs at the base of the stem-loop structure assumed by the single strand products of primer extension using as template a common genetic element, the promoter-operator of the Escherichia coli lactose operon, and may involve up to 30% of the products. The cleavage is independent of primer, template, and triphosphates, is dependent on substrate length and temperature, requires free ends and Mg2+, and is absent in DNA polymerases lacking the 5'-->3' exonuclease, such as the Stoffel fragment and the T7 DNA polymerase.