BackgroundAs the electronic health record (EHR) becomes the preferred documentation tool across medical practices, health care organizations are pushing for clinical decision support systems (CDSS) to help bring clinical decision support (CDS) tools to the forefront of patient-physician interactions. A CDSS is integrated into the EHR and allows physicians to easily utilize CDS tools. However, often CDSS are integrated into the EHR without an initial phase of usability testing, resulting in poor adoption rates. Usability testing is important because it evaluates a CDSS by testing it on actual users. This paper outlines the usability phase of a study, which will test the impact of integration of the Wells CDSS for pulmonary embolism (PE) diagnosis into a large urban emergency department, where workflow is often chaotic and high stakes decisions are frequently made. We hypothesize that conducting usability testing prior to integration of the Wells score into an emergency room EHR will result in increased adoption rates by physicians.ObjectiveThe objective of the study was to conduct usability testing for the integration of the Wells clinical prediction rule into a tertiary care center’s emergency department EHR.MethodsWe conducted usability testing of a CDS tool in the emergency department EHR. The CDS tool consisted of the Wells rule for PE in the form of a calculator and was triggered off computed tomography (CT) orders or patients’ chief complaint. The study was conducted at a tertiary hospital in Queens, New York. There were seven residents that were recruited and participated in two phases of usability testing. The usability testing employed a “think aloud” method and “near-live” clinical simulation, where care providers interacted with standardized patients enacting a clinical scenario. Both phases were audiotaped, video-taped, and had screen-capture software activated for onscreen recordings.ResultsPhase I: Data from the “think-aloud” phase of the study showed an overall positive outlook on the Wells tool in assessing a patient for a PE diagnosis. Subjects described the tool as “well-organized” and “better than clinical judgment”. Changes were made to improve tool placement into the EHR to make it optimal for decision-making, auto-populating boxes, and minimizing click fatigue. Phase II: After incorporating the changes noted in Phase 1, the participants noted tool improvements. There was less toggling between screens, they had all the clinical information required to complete the tool, and were able to complete the patient visit efficiently. However, an optimal location for triggering the tool remained controversial.ConclusionsThis study successfully combined “think-aloud” protocol analysis with “near-live” clinical simulations in a usability evaluation of a CDS tool that will be implemented into the emergency room environment. Both methods proved useful in the assessment of the CDS tool and allowed us to refine tool usability and workflow.

Two types of PDGF receptors have been cloned and sequenced. Both receptors are transmembrane glycoproteins with a ligand-stimulatable tyrosine kinase site. We have shown earlier that ligand-induced activation of the beta-type PDGF receptor is due to the conversion of the monomeric form of the receptor to the dimeric form [Bishayee et al. (1989) J. Biol. Chem. 264, 11699-11705]. In the present studies, we have established the ligand-binding specificity of two receptor types and extended it further to investigate the ligand-induced association state of the alpha-receptor and the role of alpha-receptor in the activation of beta-receptor. These studies were conducted with cells that express one or the other type of PDGF receptor as well as with cells that express both types of receptors. Moreover, ligand-binding characteristics of the receptor were confirmed by immunoprecipitation of the receptor-125I-PDGF covalent complex with type-specific anti-PDGF receptor antibodies. These studies revealed that all three isoforms of PDGF bind to alpha-receptor, and such binding leads to dimerization as well as activation of the receptor. In contrast, beta-receptor can be activated only by PDGF BB and not by PDGF AB or PDGF AA. However, by using antipeptide antibodies that are specific for alpha- or beta-type PDGF receptor, we demonstrated that in the presence of alpha-receptor, beta-receptor kinase can be activated by PDGF AB. We present here direct evidence that strongly suggests that such PDGF AB induced activation of beta-receptor is due to the formation of a noncovalently linked alpha-beta receptor heterodimer.

Ten analogues of His-Trp-Leu-Gln-Leu-Lys-Pro-Gly-Gln-Pro-Met-Tyr, the dodecapeptide alpha factor of Saccharomyces cerevisiae, were synthesized by conventional solution phase techniques and purified by using high-performance liquid chromatography. The dodecapeptide was also synthesized attached at its carboxyl terminus to poly(ethylene oxide), a macromolecular protecting group. Analogues in which Lys6 or His1 was modified exhibited high biological activity as evidenced by their ability to elicit aberrant morphologies in a cells of S. cerevisiae. These results suggest that neither a free alpha-amine nor a protonatable side chain at position 6 is necessary for biological activity of the dodecapeptide alpha factor. Although Ala2- and Phe2-dodecapeptides were not biologically active, they competed with the natural alpha factor and several active analogues. Thus binding of the alpha factor is not sufficient to elicit a biological response; it appears that the side chain in position 2 is critical for triggering morphological alterations in a cells.

Two site-specific anti-peptide antibodies (AbPj and AbP2) were raised against the platelet-derived growth factor (PDGF) receptor. These two sites correspond to amino acid residues 977 through 988 (peptide 1) and 932 through 947 (peptide 2) of the murine PDGF receptor. Both antibodies recognized human and murine PDGF receptors in immunoprecipitation and immunoblotting analyses. None of the antibodies was directed to phosphotyrosine. One of the antibodies (AbP2) showed unusual antigen recognition specificity. This antibody specifically recognized the tyrosine-phosphorylated PDGF receptor and not the unphosphorylated native receptor, suggesting that recognition by this antibody requires a specific conformation that is induced by PDGF-stimulated autophosphorylation.The human platelet-derived growth factor (PDGF) consists of a family of glycoproteins (Mr, 28,000 to 35,000) composed of two homologous but nonidentical polypeptides (A and B) of Mr 14,000 to 18,000 linked by disulfide bonds (1,7,11,17); the B chain of PDGF is a product of c-sis proto-oncogene (8, 23). PDGF initiates cellular replication and transformation by binding to a specific high-affinity cell surface receptor, a transmembrane glycoprotein of 180 kilodaltons (kDa). The PDGF receptor has recently been purified from various sources (3,6,19). The purified receptor displays PDGF-stimulated tyrosine kinase activity, suggesting that tyrosine kinase is an integral part of the receptor molecule (3,19). This conclusion has recently been confirmed by cloning of cDNA for the murine PDGF receptor; the deduced sequence has considerable homology with known tyrosine kinases (24).Unlike the well-studied receptors for epidermal growth factor and insulin, the PDGF receptor is relatively uncharacterized. Studies on biosynthesis and processing of this receptor have recently been aided by the availability of anti-PDGF-receptor antibodies (4, 10, 13). In this communication, we report the generation and characterization of a conformation-specific novel anti-PDGF-receptor antibody. It recognizes a peptide epitope (residues 932 through 947 of murine PDGF receptor) that is normally cryptic but becomes accessible upon receptor phosphorylation. This antibody, unlike other reported reagents, may be useful in future structure-function analyses of the receptor. ed by the chloramine T procedure, and '25I-PDGF was purified as described previously (3). Platelet-poor plasma, which lacks PDGF, was prepared as described previously (21).[_y-32P]ATP. Labeled ATP was prepared with 32pi (ICN) and a -y-prep A kit (Promega Biotec, Madison, Wis.) according to the manufacturers' directions. The [_y-32P]ATP was diluted with unlabeled ATP to a final specific activity of 40 to 60 Ci/mmol. Peptide synthesis. The peptides Glu-Gly-Tyr-Lys-LysLys-Tyr-Gln-Gln-Val-Asp-Glu-Glu-Phe-Leu-Arg (P2) and Tyr-Thr-Ala-Val-Gln-Pro-Asn-Glu-Ser-Asp-Asn-Asp (Pl), corresponding to the residues 932 through 947 and 977 through 988, respectively, of the murine PDGF-receptor sequence (24), were synthesized with an ...

No abstract