Group differences in physician responses to handheld presentation of clinical evidence: a verbal protocol analysis

<p>Abstract</p> <p>Background</p> <p>To identify individual differences in physicians' needs for the presentation of evidence resources and preferences for mobile devices.</p> <p>Methods</p> <p>Within-groups analysis of responses to semi-structured interviews. Interviews consisted of using prototypes in response to task-based scenarios. The prototypes were implemented on two different form factors: a tablet style PC and a pocketPC. Participants were from three user groups: general internists, family physicians and medicine residents, and from two different settings: urban and semi-urban. Verbal protocol analysis, which consists of coding utterances, was conducted on the transcripts of the testing sessions. Statistical relationships were investigated between staff physicians' and residents' background variables, self-reported experiences with the interfaces, and verbal code frequencies.</p> <p>Results</p> <p>47 physicians were recruited from general internal medicine, family practice clinics and a residency training program. The mean age of participants was 42.6 years. Physician specialty had a greater effect on device and information-presentation preferences than gender, age, setting or previous technical experience. Family physicians preferred the screen size of the tablet computer and were less concerned about its portability. Residents liked the screen size of the tablet, but preferred the portability of the pocketPC. Internists liked the portability of the pocketPC, but saw less advantage to the large screen of the tablet computer (F[2,44] = 4.94, p = .012).</p> <p>Conclusion</p> <p>Different types of physicians have different needs and preferences for evidence-based resources and handheld devices. This study shows how user testing can be incorporated into the process of design to inform group-based customization.</p

Development of a prototype clinical decision support tool for osteoporosis disease management: a qualitative study of focus groups

<p>Abstract</p> <p>Background</p> <p>Osteoporosis affects over 200 million people worldwide, and represents a significant cost burden. Although guidelines are available for best practice in osteoporosis, evidence indicates that patients are not receiving appropriate diagnostic testing or treatment according to guidelines. The use of clinical decision support systems (CDSSs) may be one solution because they can facilitate knowledge translation by providing high-quality evidence at the point of care. Findings from a systematic review of osteoporosis interventions and consultation with clinical and human factors engineering experts were used to develop a conceptual model of an osteoporosis tool. We conducted a qualitative study of focus groups to better understand physicians' perceptions of CDSSs and to transform the conceptual osteoporosis tool into a functional prototype that can support clinical decision making in osteoporosis disease management at the point of care.</p> <p>Methods</p> <p>The conceptual design of the osteoporosis tool was tested in 4 progressive focus groups with family physicians and general internists. An iterative strategy was used to qualitatively explore the experiences of physicians with CDSSs; and to find out what features, functions, and evidence should be included in a working prototype. Focus groups were conducted using a semi-structured interview guide using an iterative process where results of the first focus group informed changes to the questions for subsequent focus groups and to the conceptual tool design. Transcripts were transcribed verbatim and analyzed using grounded theory methodology.</p> <p>Results</p> <p>Of the 3 broad categories of themes that were identified, major barriers related to the accuracy and feasibility of extracting bone mineral density test results and medications from the risk assessment questionnaire; using an electronic input device such as a Tablet PC in the waiting room; and the importance of including well-balanced information in the patient education component of the osteoporosis tool. Suggestions for modifying the tool included the addition of a percentile graph showing patients' 10-year risk for osteoporosis or fractures, and ensuring that the tool takes no more than 5 minutes to complete.</p> <p>Conclusions</p> <p>Focus group data revealed the facilitators and barriers to using the osteoporosis tool at the point of care so that it can be optimized to aid physicians in their clinical decision making.</p

Novel Interactions of ESCRT-III with LIP5 and VPS4 and their Implications for ESCRT-III Disassembly

The AAA+ ATPase VPS4 plays an essential role in multivesicular body biogenesis and is thought to act by disassembling ESCRT-III complexes. VPS4 oligomerization and ATPase activity are promoted by binding to LIP5. LIP5 also binds to the ESCRT-III like protein CHMP5/hVps60, but how this affects its function remains unclear. Here we confirm that LIP5 binds tightly to CHMP5, but also find that it binds well to additional ESCRT-III proteins including CHMP1B, CHMP2A/hVps2–1, and CHMP3/hVps24 but not CHMP4A/hSnf7–1 or CHMP6/hVps20. LIP5 binds to a different region within CHMP5 than within the other ESCRT-III proteins. In CHMP1B and CHMP2A, its binding site encompasses sequences at the proteins' extreme C-termini that overlap with “MIT interacting motifs” (MIMs) known to bind to VPS4. We find unexpected evidence of a second conserved binding site for VPS4 in CHMP2A and CHMP1B, suggesting that LIP5 and VPS4 may bind simultaneously to these proteins despite the overlap in their primary binding sites. Finally, LIP5 binds preferentially to soluble CHMP5 but instead to polymerized CHMP2A, suggesting that the newly defined interactions between LIP5 and ESCRT-III proteins may be regulated by ESCRT-III conformation. These studies point to a role for direct binding between LIP5 and ESCRT-III proteins that is likely to complement LIP5's previously described ability to regulate VPS4 activity

Regulators of Vps4 ATPase Activity at Endosomes Differentially Influence the Size and Rate of Formation of Intralumenal Vesicles

Disassembly of ESCRT-III requires Vps4 ATPase activity under the control of regulatory proteins. Described here are distinct spatiotemporal functions for Vps4 regulators, with Did2 playing a unique role in regulating MVB lumenal vesicle size and Vtal-Vps60 promoting efficient membrane scission and delivery of vesicles into the endosome lumen

Ist1 Regulates Vps4 Localization and Assembly

The ESCRT protein complexes are recruited from the cytoplasm and assemble on the endosomal membrane into a protein network that functions in sorting of ubiquitinated transmembrane proteins into the multivesicular body (MVB) pathway. This transport pathway packages cargo proteins into vesicles that bud from the MVB limiting membrane into the lumen of the compartment and delivers these vesicles to the lysosome/vacuole for degradation. The dissociation of ESCRT machinery by the AAA-type ATPase Vps4 is a necessary late step in the formation of MVB vesicles. This ATP-consuming step is regulated by several Vps4-interacting proteins, including the newly identified regulator Ist1. Our data suggest that Ist1 has a dual role in the regulation of Vps4 activity: it localizes to the ESCRT machinery via Did2 where it positively regulates recruitment of Vps4 and it negatively regulates Vps4 by forming an Ist1-Vps4 heterodimer, in which Vps4 cannot bind to the ESCRT machinery. The activity of the MVB pathway might be in part determined by outcome of these two competing activities

Novel Ist1-Did2 Complex Functions at a Late Step in Multivesicular Body Sorting

In Saccharomyces cerevisiae, integral plasma membrane proteins destined for degradation and certain vacuolar membrane proteins are sorted into the lumen of the vacuole via the multivesicular body (MVB) sorting pathway, which depends on the sequential action of three endosomal sorting complexes required for transport. Here, we report the characterization of a new positive modulator of MVB sorting, Ist1. We show that endosomal recruitment of Ist1 depends on ESCRT-III. Deletion of IST1 alone does not cause cargo-sorting defects. However, synthetic genetic analysis of double mutants of IST1 and positive modulators of MVB sorting showed that ist1Δ is synthetic with vta1Δ and vps60Δ, indicating that Ist1 is also a positive component of the MVB-sorting pathway. Moreover, this approach revealed that Ist1-Did2 and Vta1-Vps60 compose two functional units. Ist1-Did2 and Vta1-Vps60 form specific physical complexes, and, like Did2 and Vta1, Ist1 binds to the AAA-ATPase Vps4. We provide evidence that the ist1Δ mutation exhibits a synthetic interaction with mutations in VPS2 (DID4) that compromise the Vps2-Vps4 interaction. We propose a model in which the Ist1-Did2 and Vta1-Vps60 complexes independently modulate late steps in the MVB-sorting pathway