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Biomedical subjects

D Cook

Publications and source records attributed to D Cook.

At least 73 records · Page 4Linked to original sources

Noninvasive positive pressure ventilation in the setting of severe, acute exacerbations of chronic obstructive pulmonary disease: more effective and less expensive.

OBJECTIVE: The use of noninvasive ventilation for patients with acute respiratory failure has become increasingly popular over the last decade. Although the literature provides good evidence for the effectiveness of noninvasive ventilation in addition to standard therapy compared with standard therapy alone in patients with chronic obstructive pulmonary disease (avoiding intubation and improving hospital mortality), the associated costs have not been rigorously measured. Adding noninvasive positive pressure ventilation (NPPV) to standard therapy in the setting of a severe, acute exacerbation of chronic obstructive pulmonary disease (COPD) in patients with respiratory acidosis who are at high risk of requiring endotracheal intubation is both more effective and less expensive. DESIGN: Economic evaluation based on theoretical model. SETTING: This analysis base case was modeled for a tertiary care, teaching hospital. PATIENTS OR OTHER PARTICIPANTS: Carefully selected patients with severe exacerbations of COPD. INTERVENTION: The two alternative therapies compared were standard therapy (oxygen, bronchodilators, steroids, and antibiotics) and standard therapy plus NPPV. MEASUREMENTS AND MAIN RESULTS: As the hypothesis was dominance, the main outcomes modeled and calculated were costs, mortality rate, and rates of intubation between the two interventions. To determine clinical effectiveness, we used a meta-analysis of randomized trials evaluating the impact of NPPV on hospital survival. A decision tree was constructed and probabilities were applied at each chance node using research evidence and a comprehensive regional database. To provide data for this economic evaluation, MEDLINE literature searches were conducted. Bibliographies of relevant articles were reviewed, as were personal files. To estimate the costs of the alternative therapeutic approaches, eight types of hospitalization days were costed using the London Health Sciences Center costing data. Sensitivity analyses were performed, varying all assumptions made. The meta-analysis yielded an odds ratio for hospital mortality in the NPPV arm, compared with standard therapy, of 0.22 (95% confidence interval, 0.10-0.66). By using baseline case assumptions, we found a cost savings of $3,244 (1996, Canadian), per patient admission, if NPPV were adopted in favor of standard therapy. These findings present a scenario of clear dominance for treatment with NPPV. Sensitivity analyses did not alter the results appreciably. CONCLUSIONS: We conclude that from a hospital's perspective, NPPV and standard therapy for carefully selected patients with acute, severe exacerbations of COPD are more effective and less expensive than standard therapy alone.

Acute Disease↗

Ventilator circuit and secretion management strategies: a Franco-Canadian survey.

OBJECTIVE: To determine the use of ventilator circuit and secretion management strategies in France and Canada. DESIGN: Binational cross-sectional survey. POPULATION: Intensive care unit (ICU) directors in French and Canadian university hospitals. MEASUREMENTS: We compared responses between countries regarding the use of seven circuit and secretion strategies, the rationales against their use, decisional responsibility for these strategies, whether ventilator-associated pneumonia (VAP) practice was audited, and whether VAP prevention guidelines addressing these strategies were used. RESULTS: The response rate was 72/84 (85.7%) for French and 31/32 (96.9%) for Canadian ICUs. Endotracheal intubation was predominantly oral in both countries. Changing the ventilator circuits only for every new patient was more frequent in France than in Canada (p < .0001). Heated humidifiers were used more in Canada than France (p = .0003). Closed endotracheal suctioning was used more frequently in Canada (p < .0001). In both countries, subglottic secretion drainage and kinetic beds were rarely used. Semirecumbent positioning was reported more often by French than Canadian ICUs (p = .003). Reasons for nonuse of these strategies included adverse effects (heat and moisture exchangers), cost (kinetic beds), lack of convincing benefit (subglottic secretion drainage), and nurse inconvenience (semirecumbency). Decisional responsibility for each strategy differed among institutions. VAP prevention practice was periodically reviewed in 53% of French and 68% of Canadian ICUs (p = .20). VAP prevention guidelines were used in 64% and 30% of these ICUs, respectively (p = .002). CONCLUSIONS: Our study does not support the notion that published recommendations substantially impact reported use of several ventilator circuit and secretion management strategies. Based on the use of more frequent ventilator circuit changes, closed suctioning systems, heated humidifiers, and respiratory therapists, ventilator circuit and secretion management practice appears more costly in Canada than in France.

Canada↗

Four genes of Medicago truncatula controlling components of a nod factor transduction pathway.

Rhizobium nodulation (Nod) factors are lipo-chitooligosaccharides that act as symbiotic signals, eliciting several key developmental responses in the roots of legume hosts. Using nodulation-defective mutants of Medicago truncatula, we have started to dissect the genetic control of Nod factor transduction. Mutants in four genes (DMI1, DMI2, DMI3, and NSP) were pleiotropically affected in Nod factor responses, indicating that these genes are required for a Nod factor-activated signal transduction pathway that leads to symbiotic responses such as root hair deformations, expressions of nodulin genes, and cortical cell divisions. Mutant analysis also provides evidence that Nod factors have a dual effect on the growth of root hair: inhibition of endogenous (plant) tip growth, and elicitation of a novel tip growth dependent on (bacterial) Nod factors. dmi1, dmi2, and dmi3 mutants are also unable to establish a symbiotic association with endomycorrhizal fungi, indicating that there are at least three common steps to nodulation and endomycorrhization in M. truncatula and providing further evidence for a common signaling pathway between nodulation and mycorrhization.

Gene Expression Regulation, Plant↗

School-based telemedicine: teachers', nurses' and administrators' perceptions.

In 1997, a telemedicine project began in Kansas which brought health-care directly into elementary schools using interactive video-links. The project initially involved four schools, but was expanded to cover 10 schools, including two middle and one high school. We examined the organizational issues related to telemedicine links to schools. Specific attention was paid to the perceptions of the nurses, teachers and key administrators. The research involved analysing archive data and interviewing participants in the project from the schools and the medical centre. The results showed the difficulties in delivering health-care, especially by telemedicine, to under-served urban children. However, the data also revealed that these can be overcome. Once they had experienced it at first hand, almost all concerned began to see telemedicine as an effective and important asset to the delivery of health-care.

Administrative Personnel↗

Development and laboratory evaluation of a new toothbrush with a novel brush head design.

Despite many developments in manual toothbrush design, plaque removal at the back of the mouth and at approximal surfaces remains inadequate, yet it is at these sites in particular that plaque accumulates and leads to the development of gingival disease. Improved oral hygiene can be achieved by better brushing technique and by increasing brushing time, but a change in behavior patterns is almost impossible to achieve for the majority of individuals. What is required is a brush head design that maximizes plaque removal, regardless of how the user brushes. As a result of a detailed investigation into the action of bistles during brushing, the Oral-B CrossAction toothbrush has been developed. It incorporates bristles angled at 16 degrees in a unique CrissCross design arranged along the horizontal axis of the toothbrush. Laboratory studies have demonstrated that this development significantly enhances interproximal penetration and cleaning effectiveness when compared with an identical brush head with vertical rather than angled bristles. Laboratory comparisons with more than 80 leading manual toothbrushes from around the world demonstrate a consistent, significant advantage for the new CrossAction toothbrush, both with respect to interproximal penetration and cleaning effectiveness. These results suggest that the CrossAction toothbrush has the potential to remove greater amounts of plaque, especially from the approximal surfaces, than conventional toothbrushes incorporating vertical bristles or more traditional tuft designs.

Adult↗

Maintaining updated DNA-based HLA assignments in the National Marrow Donor Program Bone Marrow Registry.

The National Marrow Donor Program (NMDP) has instituted an approach to address the impact of new alleles on the DNA-based HLA assignments obtained during volunteer donor typing. This approach was applied to the DRB typing results from 371,187 donors received from 14 laboratories in 1999. Samples were tested with a standardized set of sequence specific oligonucleotide reagents and the positive and negative hybridization results transmitted electronically to the NMDP. A software program interpreted the primary data into HLA assignments and rejected assignments which did not produce a result at the specified level of resolution. Comparison of the HLA assignments derived by the NMDP software to the assignments made by the laboratories using several local software prograins showed 90.5% of the assignments to be identical. Differences in assignments were explained by varying levels of typing resolution, variation in the inclusion of the second expressed DRB loci, disparity arising when alternative assignments were summarized, and failure to submit correct information. When the primary data collected in 1999 were interpreted into HLA assignments using the set of alleles defined in July 2000, 74% of the HLA-DRB assignments were altered by the description of new alleles, justifying the development of this software.

Base Sequence↗

Interaction of axin and Dvl-2 proteins regulates Dvl-2-stimulated TCF-dependent transcription.

Axin promotes the phosphorylation of beta-catenin by GSK-3beta, leading to beta-catenin degradation. Wnt signals interfere with beta-catenin turnover, resulting in enhanced transcription of target genes through the increased formation of beta-catenin complexes containing TCF transcription factors. Little is known about how GSK-3beta-mediated beta-catenin turnover is regulated in response to Wnt signals. We have explored the relationship between Axin and Dvl-2, a member of the Dishevelled family of proteins that function upstream of GSK-3beta. Expression of Dvl-2 activated TCF-dependent transcription. This was blocked by co-expression of GSK-3beta or Axin. Expression of a 59 amino acid GSK-3beta-binding region from Axin strongly activated transcription in the absence of an upstream signal. Introduction of a point mutation into full-length Axin that prevented GSK-3beta binding also generated a transcriptional activator. When co-expressed, Axin and Dvl-2 co-localized within expressing cells. When Dvl-2 localization was altered using a C-terminal CAAX motif, Axin was also redistributed, suggesting a close association between the two proteins, a conclusion supported by co-immunoprecipitation data. Deletion analysis suggested that Dvl-association determinants within Axin were contained between residues 603 and 810. The association of Axin with Dvl-2 may be important in the transmission of Wnt signals from Dvl-2 to GSK-3beta.

Adaptor Proteins, Signal Transducing↗

A descriptive study of the centralization phenomenon. A prospective analysis.

STUDY DESIGN: Occurrence and treatment responses associated with the centralization phenomenon were analyzed prospectively in 289 patients with acute neck and back pain with or without referred spinal symptoms. OBJECTIVES: To document symptom changes to mechanical assessment during initial evaluation and during consecutive visits. Using standard operational definitions, patients were categorized reliably into three inclusive and mutually exclusive pain pattern groups: centralization, noncentralization, and partial reduction. It was hypothesized that the occurrence of centralization would be less than previously reported and that the centralization group would have better treatment results. SUMMARY OF BACKGROUND DATA: Centralization has been reported to occur with high frequency during mechanical assessments of patients with acute spinal syndromes. When centralization is observed, a favorable treatment result is expected. Because centralization has not been defined consistently in the literature, the true prevalence and treatment responses associated with centralization have not been confirmed. METHODS: Consecutive patients with neck or back pain syndromes and referred to outpatient physical therapy services were categorized into three pain pattern groups by experienced therapists trained in the McKenzie system. Changes in distal pain location were scored and documented before and after each visit. Maximal pain intensity over 24 hours, perceived functional status, and number of treatment visits were compared between groups. RESULTS: Patients could be categorized reliably according to movement signs and symptoms. The centralization pain pattern group had significantly fewer visits than the other two groups (P < 0.001). Pain intensity rating and perceived function were different between the centralization and noncentralization groups (P < 0.001). There was no difference in treatment response between the centralization and partial-reduction groups (P = 0.306). Prevalence of patients assigned to the three groups was 30.8% in the centralization group, 23.2% in noncentralization, and 46% in the partial-reduction group. CONCLUSION: Categorization by changes in pain location to mechanical assessment and treatment allowed identification of patients with improved treatment outcomes and facilitated planning of conservative treatment of patients with acute spinal pain syndromes. If a proximal change in pain location is not observed by the seventh treatment visit, the results of this study support additional medical evaluation for physical or nonphysical factors that could be delaying quick resolution of the acute episode.

Acute Disease↗

Risk factors for clinically important upper gastrointestinal bleeding in patients requiring mechanical ventilation. Canadian Critical Care Trials Group.

OBJECTIVE: To evaluate the incidence and risk factors for clinically important upper gastrointestinal bleeding in critically ill patients requiring mechanical ventilation. DESIGN: In duplicate, blinded adjudicators determined the presence of clinically important gastrointestinal bleeding using a priori criteria, evaluating relevant clinical, laboratory, and diagnostic data. Cox proportional hazards regression analyses were used to examine baseline and time-dependent risk factors for bleeding. SETTING: Sixteen university-affiliated intensive care units (ICUs) in Canada. PATIENTS: A total of 1,077 critically ill ICU patients ventilated for at least 48 hrs. INTERVENTIONS: Patients were randomized to stress ulcer prophylaxis with intravenous ranitidine or nasogastric sucralfate; otherwise, management was at the discretion of the ICU team. MEASUREMENTS AND MAIN RESULTS: Demographic data included patient characteristics, Acute Physiology and Chronic Health Evaluation II score, and multiple organ dysfunction (MOD) score. Each day in the ICU, physiologic measurements including MOD score, feeding, and other treatment variables were recorded. The significant risk factors for upper gastrointestinal bleeding in the univariable analyses were low platelet count, maximum serum creatinine, maximum MOD score, maximum pulmonary component of the MOD score, maximum hepatic component of the MOD score, maximum renal component of the MOD score, enteral nutrition, and stress ulcer prophylaxis with ranitidine. The only independent predictors of bleeding in the multivariable analysis were maximum serum creatinine (relative risk = 1.16 [95% confidence interval = 1.02-1.32]), enteral nutrition (relative risk = 0.30 [95% confidence interval = 0.13-0.67]), and ranitidine administration (relative risk = 0.39 [95% confidence interval = 0.17-0.83]). CONCLUSIONS: In critically ill ventilated patients, renal failure was independently associated with an increased risk of clinically important gastrointestinal bleeding, whereas enteral nutrition and stress ulcer prophylaxis with ranitidine conferred significantly lower bleeding rates.

APACHE↗