Expediting the transfer of evidence into practice: building clinical partnerships*

A librarian/clinician partnership was fostered in one hospital through the formation of the Evidence-based Practice Committee, with an ulterior goal of facilitating the transfer of evidence into practice. The paper will describe barriers to evidence-based practice and outline the committee's strategies for overcoming these barriers, including the development and promotion of a Web-based guide to evidence-based practice specifically designed for clinicians (health professionals). Educational strategies for use of the Web-based guide will also be addressed. Advantages of this partnership are that the skills of librarians in meeting the needs of clinicians are maximized. The evidence-based practice skills of clinicians are honed and librarians make a valuable contribution to the knowledgebase of the clinical staff. The knowledge acquired through the partnership by both clinicians and librarians will increase the sophistication of the dialogue between the two groups and in turn will expedite the transfer of evidence into practice.

Evidence in support of a four transmembrane-pore-transmembrane topology model for the Arabidopsis thaliana Na+/K+ translocating AtHKT1 protein, a member of the superfamily of K+ transporters

The Arabidopsis thaliana AtHKT1 protein, a Na+/K+ transporter, is capable of mediating inward Na+ currents in Xenopus laevis oocytes and K+ uptake in Escherichia coli. HKT1 proteins are members of a superfamily of K+ transporters. These proteins have been proposed to contain eight transmembrane segments and four pore-forming regions arranged in a mode similar to that of a K+ channel tetramer. However, computer analysis of the AtHKT1 sequence identified eleven potential transmembrane segments. We have investigated the membrane topology of AtHKT1 with three different techniques. First, a gene fusion alkaline phosphatase study in E. coli clearly defined the topology of the N-terminal and middle region of AtHKT1, but the model for membrane folding of the C-terminal region had to be refined. Second, with a reticulocyte-lysate supplemented with dog-pancreas microsomes, we demonstrated that N-glycosylation occurs at position 429 of AtHKT1. An engineered unglycosylated protein variant, N429Q, mediated Na+ currents in X. laevis oocytes with the same characteristics as the wild-type protein, indicating that N-glycosylation is not essential for the functional expression and membrane targeting of AtHKT1. Five potential glycosylation sites were introduced into the N429Q. Their pattern of glycosylation supported the model based on the E. coli-alkaline phosphatase data. Third, immunocytochemical experiments with FLAG-tagged AtHKT1 in HEK293 cells revealed that the N and C termini of AtHKT1, and the regions containing residues 135–142 and 377–384, face the cytosol, whereas the region of residues 55–62 is exposed to the outside. Taken together, our results show that AtHKT1 contains eight transmembrane-spanning segments.

The translational function of nucleotide C1054 in the small subunit rRNA is conserved throughout evolution: genetic evidence in yeast.

Mutations at position C1054 of 16S rRNA have previously been shown to cause translational suppression in Escherichia coli. To examine the effects of similar mutations in a eukaryote, all three possible base substitutions and a base deletion were generated at the position of Saccharomyces cerevisiae 18S rRNA corresponding to E. coli C1054. In yeast, as in E. coli, both C1054A (rdn-1A) and C1054G (rdn-1G) caused dominant nonsense suppression. Yeast C1054U (rdn-1T) was a recessive antisuppressor, while yeast C1054-delta (rdn-1delta) led to recessive lethality. Both C1054U and two previously described yeast 18S rRNA antisuppressor mutations, G517A (rdn-2) and U912C (rdn-4), inhibited codon-nonspecific suppression caused by mutations in eukaryotic release factors, sup45 and sup35. However, among these only C1054U inhibited UAA-specific suppressions caused by a UAA-decoding mutant tRNA-Gln (SLT3). Our data implicate eukaryotic C1054 in translational termination, thus suggesting that its function is conserved throughout evolution despite the divergence of nearby nucleotide sequences.

Inferring identify from DNA profile evidence.

The controversy over the interpretation of DNA profile evidence in forensic identification can be attributed in part to confusion over the mode(s) of statistical inference appropriate to this setting. Although there has been substantial discussion in the literature of, for example, the role of population genetics issues, few authors have made explicit the inferential framework which underpins their arguments. This lack of clarity has led both to unnecessary debates over ill-posed or inappropriate questions and to the neglect of some issues which can have important consequences. We argue that the mode of statistical inference which seems to underlie the arguments of some authors, based on a hypothesis testing framework, is not appropriate for forensic identification. We propose instead a logically coherent framework in which, for example, the roles both of the population genetics issues and of the nonscientific evidence in a case are incorporated. Our analysis highlights several widely held misconceptions in the DNA profiling debate. For example, the profile frequency is not directly relevant to forensic inference. Further, very small match probabilities may in some settings be consistent with acquittal. Although DNA evidence is typically very strong, our analysis of the coherent approach highlights situations which can arise in practice where alternative methods for assessing DNA evidence may be misleading.