Biomedical subjects

David J Robinson

Publications and source records attributed to David J Robinson.

10 recordsLinked to original sources

PubMed2006

Towards a hybrid method to categorize interruptions and activities in healthcare.

OBJECTIVE: Interruptions are known to have a negative impact on activity performance. Understanding how an interruption contributes to human error is limited because there is not a standard method for analyzing and classifying interruptions. Qualitative data are typically analyzed by either a deductive or an inductive method. Both methods have limitations. In this paper, a hybrid method was developed that integrates deductive and inductive methods for the categorization of activities and interruptions recorded during an ethnographic study of physicians and registered nurses in a Level One Trauma Center. Understanding the effects of interruptions is important for designing and evaluating informatics tools in particular as well as improving healthcare quality and patient safety in general. METHOD: The hybrid method was developed using a deductive a priori classification framework with the provision of adding new categories discovered inductively in the data. The inductive process utilized line-by-line coding and constant comparison as stated in Grounded Theory. RESULTS: The categories of activities and interruptions were organized into a three-tiered hierarchy of activity. Validity and reliability of the categories were tested by categorizing a medical error case external to the study. No new categories of interruptions were identified during analysis of the medical error case. CONCLUSIONS: Findings from this study provide evidence that the hybrid model of categorization is more complete than either a deductive or an inductive method alone. The hybrid method developed in this study provides the methodical support for understanding, analyzing, and managing interruptions and workflow.

Communication↗

PubMed2005

Interruptions in workflow for RNs in a Level One Trauma Center.

An understanding of interruptions in healthcare is important for the design, implementation, and evaluation of health information systems and for the management of clinical workflow and medical errors. The purpose of this study is to identify and classify the types of interruptions experienced by ED nurses working in a Level One Trauma Center. This was an observational field study of Registered Nurses employed in a Level One Trauma Center using the shadowing method. Results of the study indicate that nurses were both recipients and initiators of interruptions. Telephone, pagers, and face-to-face conversations were the most common sources of interruptions. Unlike other industries, the outcomes caused by interruptions resulting in medical errors, decreased efficiency and increased cost have not been systematically studied in healthcare. Our study presented here is an initial step to understand the nature, causes, and effects of interruptions, and to develop interventions to manage interruptions to improve healthcare quality and patient safety. We developed an ethnographic data collection technique and a data coding method for the capturing and analysis of interruptions. The interruption data we collected are systematic, comprehensive, and close to exhaustive. They confirmed the findings from early studies by other researchers that interruptions are frequent events in critical care and other healthcare settings. We are currently using these data to analyze the workflow dynamics of ED clinicians, identify the bottlenecks of information flow, and develop interventions to improve the efficiency of emergency care through the management of interruptions.

Communication↗

PubMed2004

Ultrasound-enhanced thrombolysis for acute ischemic stroke: phase I. Findings of the CLOTBUST trial.

BACKGROUND: Tissue plasminogen activator (TPA) activity may be enhanced with ultrasound, potentially 2 MHz transcranial Doppler (TCD). The authors present Phase I data of the CLOTBUST (Combined Lysis of Thrombus in Brain ischemia using transcranial Ultrasound and Systemic TPA). SUBJECTS AND METHODS: Nonrandomized stroke patients with proximal arterial occlusion on a prebolus TCD receiving intravenous 0.9 mg/kg TPA within 3 hours after stroke onset were monitored with portable diagnostic TCD equipment and a standard headframe. Complete recanalization was defined as thrombolysis in brain ischemia (TIBI) flow grades 4-5. RESULTS: 55 patients (mean age 69 +/- 15 years, median baseline NIH Stroke Scale [NIHSS] 18, range 4-29, 90% with 3 9 points) were treated at 125 +/- 36 minutes from symptom onset. TCD monitoring began at 117 +/- 39 minutes. Complete recanalization on TCD within 2 hours after bolus was found in 20 patients (36%). Dramatic recovery (NIHSS score < or = 3) occurred in 20% at 2 hours and in 24% at 24 hours. Overall improvement by > or = 4 NIHSS points was found in 49% at 24 hours. Improvement was associated with recanalization during or shortly after TPA infusion (phi r2 = .5, P = .03); however, in 6/20 patients with complete recanalization (30%), no immediate clinical change was noticed within 2 hours. Overall symptomatic hemorrhage rate was 5.5%. CONCLUSIONS: Continuous TCD insonation for up to 2 hours at maximum intensities allowed by current bio-safety guidelines is safe. Dramatic recovery and complete recanalization shortly after TPA bolus are feasible goals for thrombolysis given with TCD monitoring.

Aged↗

PubMed2003

Contact ion pair between Na+ and PtCl(6)(2-) favored in methanol.

Ion-pair formation between a Na+ cation and the [PtCl62-] anion in methanol is observed from195Pt NMR chemical shift trends as well as from molecular dynamics computer simulations. Free energy of association calculations reveal that contact ion pairs (CIPs) are the most favored configuration in methanol, followed by solvent shared ion pairs (SSHIPs). By contrast, such ion-pair formation is not observed for comparable solutions in water.

Journal Article↗

PubMed2003

Molecular biology of umbraviruses: phantom warriors.

The genomes of umbraviruses differ from those of most other viruses in that they do not encode a coat protein, and thus no virus particles are formed in infected plants. Protection of umbraviral RNA outside the host plant, during vector transmission, utilizes the coat protein of an assistor luteovirus, but this review focuses on the mechanisms that compensate for the lack of a coat protein in processes within the host plant. As well as an RNA-dependent RNA polymerase, umbravirus genomes encode two other proteins from almost completely overlapping open reading frames. One of these is a cell-to-cell movement protein that can mediate the transport of homologous and heterologous viral RNAs through plasmodesmata without the participation of a coat protein. The other, the ORF3 protein, binds to viral RNA to form filamentous ribonucleoprotein particles that have elements of helical structure. It serves to stabilize the RNA and facilitates its transport through the vascular system of the plant. It may also be involved in protection of the viral RNA from the plant's defensive RNA-silencing response, although it is not a suppressor of silencing. The ORF3 protein also enters the cell nucleus, specifically targeting the nucleolus. Although the function of this localization is unknown, the ORF3 protein may provide a valuable tool for investigating plant nucleolar function.

Amino Acid Sequence↗

PubMed2003

An umbraviral protein, involved in long-distance RNA movement, binds viral RNA and forms unique, protective ribonucleoprotein complexes.

Umbraviruses are different from most other viruses in that they do not encode a conventional capsid protein (CP); therefore, no recognizable virus particles are formed in infected plants. Their lack of a CP is compensated for by the ORF3 protein, which fulfils functions that are provided by the CPs of other viruses, such as protection and long-distance movement of viral RNA. When the Groundnut rosette virus (GRV) ORF3 protein was expressed from Tobacco mosaic virus (TMV) in place of the TMV CP [TMV(ORF3)], in infected cells it interacted with the TMV RNA to form filamentous ribonucleoprotein (RNP) particles that had elements of helical structure but were not as uniform as classical virions. These RNP particles were observed in amorphous inclusions in the cytoplasm, where they were embedded within an electron-dense matrix material. The inclusions were detected in all types of cells and were abundant in phloem-associated cells, in particular companion cells and immature sieve elements. RNP-containing complexes similar in appearance to the inclusions were isolated from plants infected with TMV(ORF3) or with GRV itself. In vitro, the ORF3 protein formed oligomers and bound RNA in a manner consistent with its role in the formation of RNP complexes. It is suggested that the cytoplasmic RNP complexes formed by the ORF3 protein serve to protect viral RNA and may be the form in which it moves through the phloem. Thus, the RNP particles detected here represent a novel structure which may be used by umbraviruses as an alternative to classical virions.

Arachis↗

PubMed2002

Geometric hydration shells for anionic platinum group metal chloro complexes.

Solvation shells surrounding complex inorganic anions have not been extensively studied and are often mentioned with an amorphous picture in mind. We use a computational model previously validated against experimental results and ab initio quantum calculations (Lienke, A.; Klatt, G.; Robinson, D.; Koch, K. R.; Naidoo, K. J. Inorg.Chem. 2001, 40, 2352-2357) to investigate the nature of the hydration shells about simple platinum group metal chloro complexes ([PtCl(6)](2-), [RhCl(6)](3-), [PtCl(4)](2-), and [PdCl(4)](2-)). Our simulations show that the hydration shells surrounding these complexes are symmetric and take on familiar geometric forms. We find that only the [RhCl(6)](3-) complex has a clearly defined second hydration shell while the [PtCl(6)](2-), [PtCl(4)](2-), and [PdCl(4)](2-) second hydration shells are more diffuse.

Journal Article↗

PubMed2002

Solution structures of potato virus X and narcissus mosaic virus from Raman optical activity.

Potato virus X (PVX) and narcissus mosaic virus (NMV) were studied using vibrational Raman optical activity (ROA) in order to obtain new information on the structures of their coat protein subunits. The ROA spectra of the two intact virions are very similar to each other and similar to that of tobacco mosaic virus (TMV) studied previously, being dominated by signals characteristic of proteins with helix bundle folds. In particular, PVX and NMV show strong positive ROA bands at approximately 1340 cm(-1) assigned to hydrated alpha-helix and perhaps originating in surface exposed helical residues, together with less strong positive ROA intensity in the range approximately 1297-1312 cm(-1) assigned to alpha-helix in a more hydrophobic environment and perhaps originating in residues at helix-helix interfaces. The positive approximately 1340 cm(-1) ROA band of TMV is less intense than those of PVX and NMV, suggesting that TMV contains less hydrated alpha-helix. Small differences in other spectral regions reflect differences in some loop, turn and side-chain compositions and conformations among the three viruses. A pattern recognition program based on principal component analysis of ROA spectra indicates that the coat protein subunit folds of PVX and NMV may be very similar to each other and similar to that of TMV. These results suggest that PVX and NMV may have coat protein subunit structures based on folds similar to the TMV helix bundle and hence that the helical architecture of the PVX and NMV particles may be similar to that of TMV but with different structural parameters.

Capsid↗

PubMed2002

A comparison trial for stratifying intermediate-risk chest pain: benefits of emergency department observation centers.

Chest pain of uncertain etiology (intermediate-risk chest pain [IR-CP]) constitutes a majority of acute chest pain presentations to emergency departments (EDs). A before- and-after trial of 2197 IR-CP patients transferred from the hospital's ED to one of three units-ED-based observation center (ED-OC), inpatient observation center (IN-OC), and inpatient units-compared mean cost, length of stay, and safety over a 2-year period. The mean per patient cost for management of IR-CP was lower in the ED-OC ($1642) than the IN-OC ($1910) or the inpatient units ($2785). The mean length of stay was shorter in the ED-OC (0.75 days) than in the IN-OC (1.18 days) or the inpatient units (2.16 days). Return rates were lower in the ED-OC at 7 days (0%) and at 6 months (0.45%) than the IN-OC (0% and 1.22%) or the inpatient units (0.77% and 3.67%). Overall hospital costs for managing IR-CP dropped significantly (12.5%) after the ED-OC was opened. ED-OCs provide a safe and cost-effective alternative to admission of IR-CP patients.

Analysis of Variance↗

PubMed2001

A comparison of the solution structures of tobacco rattle and tobacco mosaic viruses from Raman optical activity.

Vibrational Raman optical activity (ROA) spectra of tobacco rattle virus (TRV) and tobacco mosaic virus (TMV) were measured and compared with a view to obtaining new information about the coat protein subunit structure of TRV. A sharp strong positive band observed at approximately 1344 cm(-1) in the ROA spectra of the two viruses is evidence that both contain a significant amount of a hydrated form of alpha-helix, but more in TRV than in TMV. Although the ROA spectrum of TMV shows significant positive intensity in the range approximately 1297-1312 cm(-1) characteristic of alpha-helix in a hydrophobic environment, as expected from the helix interface residues in the four-helix bundles that constitute the basic motif of the TMV coat protein fold, that of TRV shows little positive ROA intensity here. Instead TRV shows a strong positive ROA band at approximately 1315 cm(-1), of much greater intensity than bands shown here by TMV, that is characteristic of polyproline II (PPII) helix. This suggests that the additional long central and C-terminal sequences of the TRV coat proteins contain a significant amount of PPII structure, plus perhaps some beta-strand judging by a prominent sharp negative ROA band shown by TRV at approximately 1236 cm(-1), but little alpha-helix. The open flexible hydrated nature of PPII helical structure is consistent with the earlier suggestions that the additional sequences are exposed and, together with a larger amount of hydrated alpha-helix, could serve to fill the extra volume required by the larger diameter of the cylindrical TRV particles relative to those of TMV.

Capsid↗