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A Systematic Review of Metrics Utilized in the Selection and Prediction of Future Performance of Residents in the United States. J Grad Med Educ 2023; 15:652-668. [PMID: 38045930 PMCID: PMC10686656 DOI: 10.4300/jgme-d-22-00955.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 04/26/2023] [Accepted: 09/05/2023] [Indexed: 12/05/2023] Open
Abstract
Background Aligning resident and training program attributes is critical. Many programs screen and select residents using assessment tools not grounded in available evidence. This can introduce bias and inappropriate trainee recruitment. Prior reviews of this literature did not include the important lens of diversity, equity, and inclusion (DEI). Objective This study's objective is to summarize the evidence linking elements in the Electronic Residency Application Service (ERAS) application with selection and training outcomes, including DEI factors. Methods A systematic review was conducted on March 30, 2022, concordant with PRISMA guidelines, to identify the data supporting the use of elements contained in ERAS and interviews for residency training programs in the United States. Studies were coded into the topics of research, awards, United States Medical Licensing Examination (USMLE) scores, personal statement, letters of recommendation, medical school transcripts, work and volunteer experiences, medical school demographics, DEI, and presence of additional degrees, as well as the interview. Results The 2599 identified unique studies were reviewed by 2 authors with conflicts adjudicated by a third. Ultimately, 231 meeting inclusion criteria were included (kappa=0.53). Conclusions Based on the studies reviewed, low-quality research supports use of the interview, Medical Student Performance Evaluation, personal statement, research productivity, prior experience, and letters of recommendation in resident selection, while USMLE scores, grades, national ranking, attainment of additional degrees, and receipt of awards should have a limited role in this process.
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Teams of rural physicians matter: Testing a framework of team effectiveness. CANADIAN FAMILY PHYSICIAN MEDECIN DE FAMILLE CANADIEN 2022; 68:280-287. [PMID: 35418396 PMCID: PMC9007131 DOI: 10.46747/cfp.6804280] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
OBJECTIVE To examine how rural physician team effectiveness predicts outcomes of team performance, team commitment, and intentions to stay. DESIGN Surveys measuring team climate, team efficacy, and team performance were sent to rural physician team members. Surveys measuring team performance were sent to external observers in supervisory positions. SETTING Northern Ontario communities. PARTICIPANTS Rural physicians and external observers, the latter including hospital chief executive officers, family health team executive directors, and clinic managers. MAIN OUTCOMES MEASURES Total scale scores were generated using mean substitution. Cronbach α was used to assess internal consistencies of team member-level measures. Team-level measures were created by averaging the responses across team members, and intraclass correlation coefficients for each scale of each team of 2 or more members were calculated to yield a measure of rating consistency. A t test was used to assess the possible difference between team performance ratings by team members and external observers. Team-level relationships within the team effectiveness model were assessed using mediated regression, and generalized estimating equations were used to assess the relationships in the model between team-level (team efficacy) and individual-level (affective team commitment and intentions to stay) variables to address the nonindependence of these data. RESULTS Overall, 70 rural physicians from 26 Rural and Northern Physician Group Agreement communities with 2 or more physicians and 25 external observers from 19 of the 26 Rural and Northern Physician Group Agreement communities participated in the study. The findings showed that team climate (composed of decision making, communication, and conflict resolution measures) positively predicted team efficacy, which in turn positively predicted team performance. This fully mediated set of relationships held whether team performance was rated by the physicians themselves or by the external observers. Team efficacy significantly predicted affective team commitment (b value=0.69, standard error=0.08, Wald =13.89, P<.001) in the first analysis and intentions to stay (b value=0.34, standard error=0.15; Wald =5.42, P=.020) in the second analysis. However, when the other variables impacting physician retention were added to the model in predicting intentions to stay, team efficacy did not predict it above and beyond these additional predictors. CONCLUSION The findings support initiatives that attempt to enhance physician team effectiveness in rural physician teams by influencing team decision making, communication, and conflict resolution to improve team performance, physician attitudes, and commitment.
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SAFETY AND EFFICACY OF PROPHYLACTIC AMIODARONE AFTER LEFT VENTRICULAR ASSIST DEVICE IMPLANTATION. J Am Coll Cardiol 2021. [DOI: 10.1016/s0735-1097(21)02122-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Impact of Adherence to Ibrutinib on Clinical Outcomes in Real-World Patients With Chronic Lymphocytic Leukemia. J Adv Pract Oncol 2021; 12:20-28. [PMID: 33552659 PMCID: PMC7844188 DOI: 10.6004/jadpro.2021.12.1.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Chronic lymphocytic leukemia (CLL) is a B-cell neoplasm with clonal expansion of small lymphocytes. Ibrutinib, an irreversible inhibitor of Bruton tyrosine kinase (BTK), is a first-line treatment option, and recent data suggest that strict adherence is directly related to clinical outcomes. Objectives The primary objective of this study was to quantify ibrutinib adherence rates in real-world patients with CLL on ibrutinib; secondary outcomes included progression-free survival and overall survival. Methods This retrospective study included subjects who were treated at a large academic medical center over approximately 5 years. Subjects were at least 18 years, diagnosed with CLL or small lymphocytic lymphoma, and treated with ibrutinib monotherapy for at least 6 months. Adherence was quantified using the medication possession ratio (MPR), which is the ratio of the sum of days' supply of medication in a period over the number of days in that period, and was based on fill history from the medical center's specialty pharmacy. Results For the 32 subjects in this study, the mean ibrutinib adherence rate was 91.7% (range, 84.4%-100%). Only 3 subjects had disease progression, and 1 death was recorded while on therapy (all with MPR < 95%); therefore, analyses of clinical outcomes were unable to be assessed due to a low number of events. There were no statistically significant differences in rates of adherence based on baseline characteristics and adverse drug events. Conclusion In patients with CLL treated with ibrutinib, mean adherence was 91.7%, which is lower than rates seen in clinical trials.
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Novel Feature Selection for Artificial Intelligence Using Item Response Theory for Mortality Prediction. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:5729-5732. [PMID: 33019275 DOI: 10.1109/embc44109.2020.9175403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Feature selection is a critical component in supervised machine learning classification analyses. Extraneous features introduce noise and inefficiencies into the system leading to a need for feature reduction techniques. Many feature reduction models use the end-classification results in the feature reduction process, committing a circular error. Item Response Theory (IRT) examines the characteristics of features independent of the end-classification results, and provides high levels of information regarding feature utility. A two-parameter dichotomous IRT model was used to analyze 18 features from an intensive care unit data set with 2520 cases. The classification results showed that the features selected via IRT were comparable to that using more traditional machine learning approaches. Strengths and limitations of the IRT selection protocol are discussed.
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Using Item Response Theory for Explainable Machine Learning in Predicting Mortality in the Intensive Care Unit: Case-Based Approach. J Med Internet Res 2020; 22:e20268. [PMID: 32975523 PMCID: PMC7547395 DOI: 10.2196/20268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/02/2020] [Accepted: 08/08/2020] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Supervised machine learning (ML) is being featured in the health care literature with study results frequently reported using metrics such as accuracy, sensitivity, specificity, recall, or F1 score. Although each metric provides a different perspective on the performance, they remain to be overall measures for the whole sample, discounting the uniqueness of each case or patient. Intuitively, we know that all cases are not equal, but the present evaluative approaches do not take case difficulty into account. OBJECTIVE A more case-based, comprehensive approach is warranted to assess supervised ML outcomes and forms the rationale for this study. This study aims to demonstrate how the item response theory (IRT) can be used to stratify the data based on how difficult each case is to classify, independent of the outcome measure of interest (eg, accuracy). This stratification allows the evaluation of ML classifiers to take the form of a distribution rather than a single scalar value. METHODS Two large, public intensive care unit data sets, Medical Information Mart for Intensive Care III and electronic intensive care unit, were used to showcase this method in predicting mortality. For each data set, a balanced sample (n=8078 and n=21,940, respectively) and an imbalanced sample (n=12,117 and n=32,910, respectively) were drawn. A 2-parameter logistic model was used to provide scores for each case. Several ML algorithms were used in the demonstration to classify cases based on their health-related features: logistic regression, linear discriminant analysis, K-nearest neighbors, decision tree, naive Bayes, and a neural network. Generalized linear mixed model analyses were used to assess the effects of case difficulty strata, ML algorithm, and the interaction between them in predicting accuracy. RESULTS The results showed significant effects (P<.001) for case difficulty strata, ML algorithm, and their interaction in predicting accuracy and illustrated that all classifiers performed better with easier-to-classify cases and that overall the neural network performed best. Significant interactions suggest that cases that fall in the most arduous strata should be handled by logistic regression, linear discriminant analysis, decision tree, or neural network but not by naive Bayes or K-nearest neighbors. Conventional metrics for ML classification have been reported for methodological comparison. CONCLUSIONS This demonstration shows that using the IRT is a viable method for understanding the data that are provided to ML algorithms, independent of outcome measures, and highlights how well classifiers differentiate cases of varying difficulty. This method explains which features are indicative of healthy states and why. It enables end users to tailor the classifier that is appropriate to the difficulty level of the patient for personalized medicine.
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SUN-370 TOLVAPTAN USE IN YOUNG ADULTS WITH RAPIDLY PROGRESSING AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE. Kidney Int Rep 2020. [DOI: 10.1016/j.ekir.2020.02.909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Perceptions of effective leadership in a medical school context. CANADIAN MEDICAL EDUCATION JOURNAL 2019; 10:e101-e106. [PMID: 31388383 PMCID: PMC6681927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
BACKGROUND There have been calls for the development of leadership attributes in healthcare practitioners through leadership development programs. However, understanding how leadership is conceptualized is needed to assure effective participant-centred leadership development programs. The purpose of this study was to elucidate how the construct of leadership is conceptualized by multiple stakeholder groups associated with medical school leadership programs. METHODS We conducted a total of 77 semi-structured interviews with six major demographic groups: Trainees (n = 16), Mid-Level University Leaders (n = 10), Clinician Leaders (n = 17), Senior University Leaders (n = 10), Medical Scientists (n = 12), and Senior Leaders, external to the University (n = 12) to address the research question. RESULTS Content analyses revealed that the leaders were expected to create a compelling vision and a foster a motivating culture within the organization. Integrity and a sense of passion about leading were viewed as being principal characteristics of a leader. The twin skills of technical competence and communication were endorsed as most important for a leader. Finally, leaders are expected to be accountable for outcomes. CONCLUSION Medical school leadership training programs should strive to incorporate these characteristics, given their broad appeal to diverse interest groups.
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Preclinical activity and safety of STRO-002, a novel ADC targeting folate receptor alpha for ovarian cancer. Gynecol Oncol 2018. [DOI: 10.1016/j.ygyno.2018.04.109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Purpose This study sought to identify the barriers and enablers to leadership enactment in academic health-care settings. Design/methodology/approach Semi-structured interviews ( n = 77) with programme stakeholders (medical school trainees, university leaders, clinical leaders, medical scientists and directors external to the medical school) were conducted, and the responses content-analysed. Findings Both contextual and individual factors were identified as playing a role in affecting academic health leadership enactment that has an impact on programme development, success and maintenance. Contextual factors included sufficient resources allocated to the programme, opportunities for learners to practise leadership skills, a competent team around the leader once that person is in place, clear expectations for the leader and a culture that fosters open communication. Contextual barriers included highly bureaucratic structures, fear-of-failure and non-trusting cultures and inappropriate performance systems. Programmes were advised to select participants based on self-awareness, strong communication skills and an innovative thinking style. Filling specific knowledge and skill gaps, particularly for those not trained in medical school, was viewed as essential. Ineffective decision-making styles and tendencies to get involved in day-to-day activities were barriers to the development of academic health leaders. Originality/value Programmes designed to develop academic health-care leaders will be most effective if they develop leadership at all levels; ensure that the organisation's culture, structure and processes reinforce positive leadership practices; and recognise the critical role of teams in supporting its leaders.
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Short form version of the Quality of Trauma Care Patient-Reported Experience Measure (SF QTAC-PREM). BMC Res Notes 2017; 10:693. [PMID: 29208046 PMCID: PMC5718023 DOI: 10.1186/s13104-017-3031-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 11/29/2017] [Indexed: 12/15/2022] Open
Abstract
Objective To enable the valid and reliable measurement of patient experiences we previously published a multicenter multi-center validation of the Quality of Trauma Care Patient-Reported Experience Measure (QTAC-PREM). The purpose of this study was to derive a simplified, short form version of the QTAC-PREM to further enhance the feasibility of measuring patient experiences in injury care. To identify candidate items for the short form we reviewed the results of the original multi-center long form validation cohort study, which included 400 injury care patients and their family members recruited from three trauma centers. We only included the best performing items on the revised short form. Results The acute care component of the measure was shortened by 30% and the post-acute care component was shortened by 42%. We identified two subscales on the acute measure (information and communication; clinical and ancillary care) and one subscale on the post-acute measure (post-discharge information and communication). The measurement properties of the short form measure were similar to that of the validated long form. This short form assessment of patient injury care experiences offers a useful, practical, and easy tool for trauma centers to implement for service evaluation, quality improvement, and injury care research. Electronic supplementary material The online version of this article (10.1186/s13104-017-3031-9) contains supplementary material, which is available to authorized users.
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A stakeholder-based approach to leadership development training: the case of medical education in Canada. INTERNATIONAL JOURNAL OF TRAINING AND DEVELOPMENT 2017. [DOI: 10.1111/ijtd.12104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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STRO-001, A NOVEL ANTI-CD74 ANTIBODY DRUG CONJUGATE (ADC) FOR TREATMENT OF B-CELL NON-HODGKIN'S LYMPHOMAS (NHL). Hematol Oncol 2017. [DOI: 10.1002/hon.2438_121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Despite continuing bouts of downsizing in North America, there is relatively little literature on Canadian white-collar workers' experience of this kind of job loss. In the present context “downsizing” refers to nonperformance-based job loss, that is, job loss through restructuring, strategic planning, or other organizational initiatives wherein individuals lose their jobs through no fault of their own. From fall of 1992 and through the winter of 1993, we conducted interviews with 144 mostly white collar displaced workers in and around Calgary, Alberta. Their perceptions of many aspects of the downsizing experience are described. The advice our participants gave to others may be of direct use. Several issues that clearly need research are also noted.
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Abstract
This study examined a variety of predictors as they related to survival of small businesses and their perceived success. Specifically, we assessed the relationships of perceptions of success and survival of small businesses with the motivational sources to begin the business, the four requirements cited by Drucker (1985), marketing and business planning activity, financial base, handling of business problems and identified sources of assistance with those problems, and demographics or business backgrounds of the small business owners. 128 small business owners representing the service, manufacturing, and retail sectors were interviewed. The marketing variables were the only ones that were predictive of success, suggesting the need for a more comprehensive framework to assess success of small businesses.
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GABA and Glutamate in Children with Primary Complex Motor Stereotypies: An 1H-MRS Study at 7T. AJNR Am J Neuroradiol 2016; 37:552-7. [PMID: 26542237 DOI: 10.3174/ajnr.a4547] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 08/12/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND PURPOSE Complex motor stereotypies are rhythmic, repetitive, fixed, purposeful but purposeless movements that stop with distraction. They can occur in otherwise normal healthy children (primary stereotypies) as well in those with autism spectrum disorders (secondary stereotypies). The underlying neurobiologic basis for these movements is unknown but is thought to involve cortical-striatal-thalamo-cortical pathways. To further clarify potential neurochemical alterations, gamma-aminobutyric acid (GABA), glutamate, glutamine, N-acetylaspartate, and choline levels were measured in 4 frontostriatal regions by using (1)H MRS at 7T. MATERIALS AND METHODS A total of 18 children with primary complex motor stereotypies and 24 typically developing controls, ages 5-10 years, completed MR spectroscopy at 7T. Single voxel STEAM acquisitions from the anterior cingulate cortex, premotor cortex, dorsolateral prefrontal cortex, and striatum were obtained, and metabolites were quantified with respect to Cr by using LCModel. RESULTS The 7T scan was well tolerated by all the participants. Compared with the controls, children with complex motor stereotypies had lower levels of GABA in the anterior cingulate cortex (GABA/Cr, P = .049; GABA/Glu, P = .051) and striatum (GABA/Cr, P = .028; GABA/Glu, P = .0037) but not the dorsolateral prefrontal cortex or the premotor cortex. Glutamate, glutamine, NAA, and Cho levels did not differ between groups in any of the aforementioned regions. Within the complex motor stereotypies group, reduced GABA to Cr in the anterior cingulate cortex was significantly associated with greater severity of motor stereotypies (r = -0.59, P = .021). CONCLUSIONS These results indicate possible GABAergic dysfunction within corticostriatal pathways in children with primary complex motor stereotypies.
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Abstract
Purpose
– The purpose of this paper is to identify managerial and organizational characteristics and behaviors that facilitate the fostering of a just and trusting culture within the healthcare system.
Design/methodology/approach
– Two studies were conducted. The initial qualitative one was used to identify themes based on interviews with health care workers that facilitate a just and trusting culture. The quantitative one used a policy-capturing design to determine which factors were most likely to predict outcomes of manager and organizational trust.
Findings
– The factors of violation type (ability vs integrity), providing an explanation or not, blame vs no blame by manager, and blame vs no blame by organization were all significant predictors of perceptions of trust.
Research limitations/implications
– Limitations to the generalizability of findings included both a small and non-representative sample from one health care region.
Practical implications
– The present findings can be useful in developing training systems for managers and organizational executive teams for managing medical error events in a manner that will help develop a just and trusting culture.
Social implications
– A just and trusting culture should enhance the likelihood of reporting medical errors. Improved reporting, in turn, should enhance patient safety.
Originality/value
– This is the first field study experimentally manipulating aspects of organizational trust within the health care sector. The use of policy-capturing is a unique feature that sheds light into the decision-making of health care workers as to the efficaciousness of particular managerial and organizational characteristics that impact a just and trusting culture.
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The use of cognitive interviews to revise the Quality of Trauma Care Patient-Reported Experience Measure (QTAC-PREM). Qual Life Res 2015; 24:1911-9. [PMID: 25589232 DOI: 10.1007/s11136-015-0919-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2015] [Indexed: 11/26/2022]
Abstract
PURPOSE The "Quality of Trauma Care Patient-Reported Experience Measure" is the first measure of patient experiences with overall injury care. The objective of this study was to use cognitive interviews to inform revision of the measure into a parsimonious set of items that function as intended, in preparation for multicenter testing. METHODS Concurrent and retrospective cognitive interviews with injured patients (n = 17) and family members (n = 13) using semi-structured interview guides. Responses were analyzed using thematic analysis. RESULTS Six broad themes were identified and guided revisions: (1) participants did not have the information to answer items (n = 9); (2) items were ambiguous or were inconsistently interpreted (n = 13); (3) items did not measure the intended constructs (n = 6); (4) items included assumptions about healthcare processes (n = 4); (5) items measured non-priority aspects of injury care (n = 8); and (6) items were redundant (n = 5). Two issues resulted in key conceptual and content changes: participants' difficulty to evaluate pre-hospital, emergency department, and intensive care unit services due to recall issues and the challenge to evaluate the effectiveness and equity of care. In total, 39 items were deleted, 28 new items developed, and the final instrument included 63 items. CONCLUSIONS Our results informed changes to item content, format, and response options. This study highlights key issues to consider when incorporating patient/family perspectives into quality measurement, most notably, that few participants can assess the quality of care in the pre-hospital and emergency department phases of care and that novel methods are needed to evaluate the effectiveness and equity of care.
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Trauma Association of Canada (TAC) Annual Scientific Meeting. The Westin Whistler Resort & Spa, Whistler, BC, Thursday, Apr. 11 to Saturday, Apr. 13, 2013Testing the reliability of tools for pediatric trauma teamwork evaluation in a North American high-resource simulation settingThe association of etomidate with mortality in trauma patientsDefinition of isolated hip fractures as an exclusion criterion in trauma centre performance evaluations: a systematic reviewEstimation of acute care hospitalization costs for trauma hospital performance evaluation: a systematic reviewHospital length of stay following admission for traumatic injury in Canada: a multicentre cohort studyPredictors of hospital length of stay following traumatic injury: a multicentre cohort studyInfluence of the heterogeneity in definitions of an isolated hip fracture used as an exclusion criterion in trauma centre performance evaluations: a multicentre cohort studyPediatric trauma, advocacy skills and medical studentsCompliance with the prescribed packed red blood cell, fresh frozen plasma and platelet ratio for the trauma transfusion pathway at a level 1 trauma centreEarly fixed-wing aircraft activation for major trauma in remote areasDevelopment of a national, multi-disciplinary trauma crisis resource management curriculum: results from the pilot courseThe management of blunt hepatic trauma in the age of angioembolization: a single centre experienceEarly predictors of in-hospital mortality in adult trauma patientsThe impact of open tibial fracture on health service utilization in the year preceding and following injuryA systematic review and meta-analysis of the efficacy of red blood cell transfusion in the trauma populationSources of support for paramedics managing work-related stress in a Canadian EMS service responding to multisystem trauma patientsAnalysis of prehospital treatment of pain in the multisystem trauma patient at a community level 2 trauma centreIncreased mortality associated with placement of central lines during trauma resuscitationChronic pain after serious injury — identifying high risk patientsEpidemiology of in-hospital trauma deaths in a Brazilian university teaching hospitalIncreased suicidality following major trauma: a population-based studyDevelopment of a population-wide record linkage system to support trauma researchInduction of hmgb1 by increased gut permeability mediates acute lung injury in a hemorrhagic shock and resuscitation mouse modelPatients who sustain gunshot pelvic fractures are at increased risk for deep abscess formation: aggravated by rectal injuryAre we transfusing more with conservative management of isolated blunt splenic injury? A retrospective studyMotorcycle clothesline injury prevention: Experimental test of a protective deviceA prospective analysis of compliance with a massive transfusion protocol - activation alone is not enoughAn evaluation of diagnostic modalities in penetrating injuries to the cardiac box: Is there a role for routine echocardiography in the setting of negative pericardial FAST?Achievement of pediatric national quality indicators — an institutional report cardProcess mapping trauma care in 2 regional health authorities in British Columbia: a tool to assist trauma sys tem design and evaluationPatient safety checklist for emergency intubation: a systematic reviewA standardized flow sheet improves pediatric trauma documentationMassive transfusion in pediatric trauma: a 5-year retrospective reviewIs more better: Does a more intensive physiotherapy program result in accelerated recovery for trauma patients?Trauma care: not just for surgeons. Initial impact of implementing a dedicated multidisciplinary trauma team on severely injured patientsThe role of postmortem autopsy in modern trauma care: Do we still need them?Prototype cervical spine traction device for reduction stabilization and transport of nondistraction type cervical spine injuriesGoing beyond organ preservation: a 12-year review of the beneficial effects of a nonoperative management algorithm for splenic traumaAssessing the construct validity of a global disability measure in adult trauma registry patientsThe mactrauma TTL assessment tool: developing a novel tool for assessing performance of trauma traineesA quality improvement approach to developing a standardized reporting format of ct findings in blunt splenic injuriesOutcomes in geriatric trauma: what really mattersFresh whole blood is not better than component therapy (FFP:RBC) in hemorrhagic shock: a thromboelastometric study in a small animal modelFactors affecting mortality of chest trauma patients: a prospective studyLong-term pain prevalence and health related quality of life outcomes for patients enrolled in a ketamine versus morphine for prehospital traumatic pain randomized controlled trialDescribing pain following trauma: predictors of persistent pain and pain prevalenceManagement strategies for hemorrhage due to pelvic trauma: a survey of Canadian general surgeonsMajor trauma follow-up clinic: Patient perception of recovery following severe traumaLost opportunities to enhance trauma practice: culture of interprofessional education and sharing among emergency staffPrehospital airway management in major trauma and traumatic brain injury by critical care paramedicsImproving patient selection for angiography and identifying risk of rebleeding after angioembolization in the nonoperative management of high grade splenic injuriesFactors predicting the need for angioembolization in solid organ injuryProthrombin complex concentrates use in traumatic brain injury patients on oral anticoagulants is effective despite underutilizationThe right treatment at the right time in the right place: early results and associations from the introduction of an all-inclusive provincial trauma care systemA multicentre study of patient experiences with acute and postacute injury carePopulation burden of major trauma: Has introduction of an organized trauma system made a difference?Long-term functional and return to work outcomes following blunt major trauma in Victoria, AustraliaSurgical dilemma in major burns victim: heterotopic ossification of the tempromandibular jointWhich radiological modality to choose in a unique penetrating neck injury: a differing opinionThe Advanced Trauma Life Support (ATLS) program in CanadaThe Rural Trauma Team Development Course (RTTDC) in Pakistan: Is there a role?Novel deployment of BC mobile medical unit for coverage of BMX world cup sporting eventIncidence and prevalence of intra-abdominal hypertension and abdominal compartment syndrome in critically ill adults: a systematic review and meta-analysisRisk factors for intra-abdominal hypertension and abdominal compartment syndrome in critically ill or injured adults: a systematic review and meta-analysisA comparison of quality improvement practices at adult and pediatric trauma centresInternational trauma centre survey to evaluate content validity, usability and feasibility of quality indicatorsLong-term functional recovery following decompressive craniectomy for severe traumatic brain injuryMorbidity and mortality associated with free falls from a height among teenage patients: a 5-year review from a level 1 trauma centreA comparison of adverse events between trauma patients and general surgery patients in a level 1 trauma centreProcoagulation, anticoagulation and fibrinolysis in severely bleeding trauma patients: a laboratorial characterization of the early trauma coagulopathyThe use of mobile technology to facilitate surveillance and improve injury outcome in sport and physical activityIntegrated knowledge translation for injury quality improvement: a partnership between researchers and knowledge usersThe impact of a prevention project in trauma with young and their learningIntraosseus vascular access in adult trauma patients: a systematic reviewThematic analysis of patient reported experiences with acute and post-acute injury careAn evaluation of a world health organization trauma care checklist quality improvement pilot programProspective validation of the modified pediatric trauma triage toolThe 16-year evolution of a Canadian level 1 trauma centre: growing up, growing out, and the impact of a booming economyA 20-year review of trauma related literature: What have we done and where are we going?Management of traumatic flail chest: a systematic review of the literatureOperative versus nonoperative management of flail chestEmergency department performance of a clinically indicated and technically successful emergency department thoracotomy and pericardiotomy with minimal equipment in a New Zealand institution without specialized surgical backupBritish Columbia’s mobile medical unit — an emergency health care support resourceRoutine versus ad hoc screening for acute stress: Who would benefit and what are the opportunities for trauma care?A geographical analysis of the Early Development Instrument (EDI) and childhood injuryDevelopment of a pediatric spinal cord injury nursing course“Kids die in driveways” — an injury prevention campaignEpidemiology of traumatic spine injuries in childrenA collaborative approach to reducing injuries in New Brunswick: acute care and injury preventionImpact of changes to a provincial field trauma triage tool in New BrunswickEnsuring quality of field trauma triage in New BrunswickBenefits of a provincial trauma transfer referral system: beyond the numbersThe field trauma triage landscape in New BrunswickImpact of the Rural Trauma Team Development Course (RTTDC) on trauma transfer intervals in a provincial, inclusive trauma systemTrauma and stress: a critical dynamics study of burnout in trauma centre healthcare professionalsUltrasound-guided pediatric forearm fracture reduction with sedation in the emergency departmentBlock first, opiates later? The use of the fascia iliaca block for patients with hip fractures in the emergency department: a systematic reviewRural trauma systems — demographic and survival analysis of remote traumas transferred from northern QuebecSimulation in trauma ultrasound trainingIncidence of clinically significant intra-abdominal injuries in stable blunt trauma patientsWake up: head injury management around the clockDamage control laparotomy for combat casualties in forward surgical facilitiesDetection of soft tissue foreign bodies by nurse practitioner performed ultrasoundAntihypertensive medications and walking devices are associated with falls from standingThe transfer process: perspectives of transferring physiciansDevelopment of a rodent model for the study of abdominal compartment syndromeClinical efficacy of routine repeat head computed tomography in pediatric traumatic brain injuryEarly warning scores (EWS) in trauma: assessing the “effectiveness” of interventions by a rural ground transport service in the interior of British ColumbiaAccuracy of trauma patient transfer documentation in BCPostoperative echocardiogram after penetrating cardiac injuries: a retrospective studyLoss to follow-up in trauma studies comparing operative methods: a systematic reviewWhat matters where and to whom: a survey of experts on the Canadian pediatric trauma systemA quality initiative to enhance pain management for trauma patients: baseline attitudes of practitionersComparison of rotational thromboelastometry (ROTEM) values in massive and nonmassive transfusion patientsMild traumatic brain injury defined by GCS: Is it really mild?The CMAC videolaryngosocpe is superior to the glidescope for the intubation of trauma patients: a prospective analysisInjury patterns and outcome of urban versus suburban major traumaA cost-effective, readily accessible technique for progressive abdominal closureEvolution and impact of the use of pan-CT scan in a tertiary urban trauma centre: a 4-year auditAdditional and repeated CT scan in interfacilities trauma transfers: room for standardizationPediatric trauma in situ simulation facilitates identification and resolution of system issuesHospital code orange plan: there’s an app for thatDiaphragmatic rupture from blunt trauma: an NTDB studyEarly closure of open abdomen using component separation techniqueSurgical fixation versus nonoperative management of flail chest: a meta-analysisIntegration of intraoperative angiography as part of damage control surgery in major traumaMass casualty preparedness of regional trauma systems: recommendations for an evaluative frameworkDiagnostic peritoneal aspirate: An obsolete diagnostic modality?Blunt hollow viscus injury: the frequency and consequences of delayed diagnosis in the era of selective nonoperative managementEnding “double jeopardy:” the diagnostic impact of cardiac ultrasound and chest radiography on operative sequencing in penetrating thoracoabdominal traumaAre trauma patients with hyperfibrinolysis diagnosed by rotem salvageable?The risk of cardiac injury after penetrating thoracic trauma: Which is the better predictor, hemodynamic status or pericardial window?The online Concussion Awareness Training Toolkit for health practitioners (CATT): a new resource for recognizing, treating, and managing concussionThe prevention of concussion and brain injury in child and youth team sportsRandomized controlled trial of an early rehabilitation intervention to improve return to work Rates following road traumaPhone call follow-upPericardiocentesis in trauma: a systematic review. Can J Surg 2013. [DOI: 10.1503/cjs.005813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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SU-E-I-40: Reconstruction of Sparse Images from Few-View Cone-Beam Data. Med Phys 2011. [DOI: 10.1118/1.3611613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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The Manchester Driver Behaviour Questionnaire as a predictor of road traffic accidents. THEORETICAL ISSUES IN ERGONOMICS SCIENCE 2011. [DOI: 10.1080/14639220903023376] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
While most validity indices are based on total test scores, this paper describes a method for quantifying the construct validity of items. The approach is based on the item selection technique originally described by Piazza in 1980. Unfortunately, Piazza's P2 index suffers from some substantial limitations. The Dm coefficient provides an alternative which can be used for item selection and provides a validity index for a set of items. The index is similar to that of traditional criterion-related validity indices. Criterion-related validity is used to demonstrate the accuracy of hypothesized relations of the measure with outcome variables of interest in research and practice. This method may be useful when the sample of items or persons is small, rendering more traditional approaches such as factor analysis or item response theory inappropriate. An example of how to use the technique is provided.
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Bringing group-level personality to the electronic realm: A comparison of face-to-face and virtual contexts. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/10887150802371773] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Synthesis of and evaluation of lipid A modification by 4-substituted 4-deoxy arabinose analogs as potential inhibitors of bacterial polymyxin resistance. Bioorg Med Chem Lett 2007; 18:1507-10. [PMID: 18187325 DOI: 10.1016/j.bmcl.2007.12.061] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 12/21/2007] [Accepted: 12/21/2007] [Indexed: 11/18/2022]
Abstract
Three sets of novel 4-deoxy-l-arabinose analogs were synthesized and evaluated as potential inhibitors of the bacterial resistance mechanism in which lipid A, on the outer membrane, is modified with 4-amino-4-deoxy-l-arabinose (l-Ara4N). One compound diminished the transfer of l-Ara4N onto lipid A. These results suggest that small molecules might be designed that would effect the same reversal of bacterial resistance observed in genetic knockouts.
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Synthesis and characterization of the colistin peptide polymyxin E1 and related antimicrobial peptides. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2001; 57:175-87. [PMID: 11298918 DOI: 10.1111/j.1399-3011.2001.00835.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two strategies were developed to synthesize the acylated cyclic peptides know as polymyxins. Synthesis of polymyxin E1 and several analogs enabled us to evaluate the minimum inhibitory concentration of individual compounds against Gram-negative bacteria. In this study we also report the first identification of two component peptides in the complex polymyxin fermentation product colistin, a Thr2Ser isoform and an acyl group isomer. Both of these peptides, as well as a known component peptide, Leu7Ile, were similar to polymyxin E1 in potency, suggesting that conservative mutations in the colistin family are functionally inconsequential. In contrast, the acyclic analogs of all of these peptides were inactive, indicating that the characteristic lariat structure of the polymyxins is necessary for antimicrobial activity.
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A justice explanation of employee reactions to office relocation: A case study. PSYCHOLOGIST-MANAGER JOURNAL 2000. [DOI: 10.1037/h0095884] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
As a strategy to increase the penetration of antibiotic drugs through the outer membrane of gram-negative pathogens, facilitated transport through siderophore receptors has been frequently exploited. Hydroxamic acids, catechols, or very close isosteres of catechols, which are mimics of naturally occurring siderophores, have been used successfully as covalently linked escorting moieties, but a much wider diversity of iron binding motifs exists. This observation, coupled to the relative lack of specificity of siderophore receptors, prompted us to initiate a program to identify novel, noncatechol siderophoric structures. We screened over 300 compounds for their ability to (1) support growth in low iron medium of a Pseudomonas aeruginosa siderophore biosynthesis deletion mutant, or (2) compete with a bactericidal siderophore-antibiotic conjugate for siderophore receptor access. From these assays we identified a set of small molecules that fulfilled one or both of these criteria. We then synthesized these compounds with functional groups suitable for attachment to both monobactam and cephalosporin core structures. Siderophore-beta-lactam conjugates then were tested against a panel of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus strains. Although several of the resultant chimeric compounds had antimicrobial activity approaching that of ceftazidime, and most compounds demonstrated very potent activity against their cellular targets, only a single compound was obtained that had enhanced, siderophore-mediated antibacterial activity. Results with tonB mutants frequently showed increased rather than decreased susceptibilities. suggesting that multiple factors influenced the intracellular concentration of the drugs.
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Abstract
Release of virulence factors in Pseudomonas aeruginosa is regulated by two N-acylhomoserine lactones, PAI-1 and PAI-2, that activate the respective transcription factors LasR and RhlR. With the goal of developing novel therapeutic agents, we synthesized constrained analogs of PAI-1 and evaluated them in P. aeruginosa. Two of the novel analogs bound to LasR and showed agonist activity in LasR stimulation of a lasI-lacZ reporter construct.
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Measuring entrepreneurship with the General Enterprising Tendency (GET) Test: criterion-related validity and reliability. HUMAN SYSTEMS MANAGEMENT 1999. [DOI: 10.3233/hsm-1999-18106] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The General Enterprising Tendency (GET) Test is a 54-item questionnaire that was designed to assess five dimensions of personality: Need for Achievement, Autonomy, Drive and Determination, Risk Taking, and Creativity. These dimensions have been thought to be predictive of an entrepreneurial personality. We evaluated the five subscales and the total GET Test scores with regard to their criterion-related validities in predicting success in small business, internal consistencies, and test-retest reliabilities. One hundred twenty-eight owners of a variety of small businesses took part in this study, and the results indicated that the GET Test needs further refinement, even if it is to be used in a research context.
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La psychologie industrielle/organisationelle et les nouveaux besoins du monde du travail au Canada à l’aube du millénaire. CANADIAN PSYCHOLOGY-PSYCHOLOGIE CANADIENNE 1998. [DOI: 10.1037/h0092482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Graduate training in I-O psychology: Some oft-ignored contextual issues. CANADIAN PSYCHOLOGY-PSYCHOLOGIE CANADIENNE 1998. [DOI: 10.1037/h0086802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Incubation of 3T3-L1 fibroblasts with insulin (10 nM or 100 nM) for 24 or 48 hours resulted in a significant increase in the amount of farnesylated p21Ras with a concomitant increase in the amount of GTP-loaded p21Ras. Cells preincubated with 100 nM insulin for 24 or 48 hours exhibited further 5-8 fold increases in p21Ras.GTP loading in response to an acute (10 minute) challenge with either insulin, EGF, or IGF-1. Effects of hyperinsulinemia were completely abolished by the presence of 1 microM alpha-hydroxyfarnesylphosphonic acid, a potent inhibitor of farnesyltransferase. These novel observations indicate that hyperinsulinemia increases the cellular pool of farnesylated p21Ras and thereby potentiates activation of p21Ras by growth factors.
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A pseudopeptide incorporating the tetrahydrophthalazine nucleus, a constrained aza analog of phenylalanine. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1996; 47:142-7. [PMID: 8740962 DOI: 10.1111/j.1399-3011.1996.tb01337.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Replacement of the alpha-carbon with a nitrogen in alpha-amino acids gives rise to azaamino acids. Most examples of azaamino acids that have been incorporated into peptides are linear analogs, in which conformational effects are restricted to the immediate vicinity of the urea bond. In contrast to the linear azaamino acids, the heterocyclic analogs might be expected to exhibit stronger conformational preferences, but examples of this class of azaamino acids are very limited. We synthesized tetrahydrophthalazine (THPhth) as a constrained phenylalanine analog and elaborated it into the model pseudotripeptide N-¿([N-alanyl]-1,2,3,4-tetrahydro-2-phthalazinyl)carbonyl)¿-L-alan ine (1). As shown by NMR studies, tetrahydrophthalazine 1A has a secondary structure in which psi THphth is fixed at 16-18 degrees and there are two equal populations of cis and trans amide bonds from the N-terminal alanine.
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Development of highly potent inhibitors of Ras farnesyltransferase possessing cellular and in vivo activity. J Med Chem 1996; 39:224-36. [PMID: 8568812 DOI: 10.1021/jm950642a] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Analogs of CVFM (a known nonsubstrate farnesyltransferase (FT) inhibitor derived from a CA1A2X sequence where C is cysteine, A is an aliphatic residue, and X is any residue) were prepared where phenylalanine was replaced by (Z)-dehydrophenylalanine, 2-aminoindan-2-carboxylate, 1,2,3,4-tetrahydroisoquinoline-3-carboxylate (Tic), and indoline-2-carboxylate. The greatest improvement in FT inhibitory potency was observed for the Tic derivative (IC50 = 1 nM); however, this compound was ineffective in blocking oncogenic Ras-induced transformation of NIH-3T3 fibroblast cells. A compound was prepared in which both the Cys-Val methyleneamine isostere and the Tic replacement were incorporated. This derivative inhibited FT with an IC50 of 0.6 nM and inhibited anchorage-independent growth of stably transformed NIH-3T3 fibroblast cells by 50% at 5 microM. Replacing the A1 side chain of this derivative with a tert-butyl group and replacing the X position with glutamine led to a derivative with an IC50 of 2.8 nM and an EC50 of 0.19 microM, a 26-fold improvement over (S*,R*)-N-[[2-[N-(2-amino-3-mercaptopropyl)-L-valyl]-1,2,3,4- tetrahydro-3-isoquinolinyl]carbonyl]-L-methionine. This derivative, (S*,R*)-N-[[2-[N-(2-amino-3-mercaptopropyl)-L-tert-leucyl]-1,2,3,4 - tetrahydro-3-isoquinolinyl]-carbonyl]-L-glutamine, was evaluated in vivo along with (S*,R*)-N-[[2-[N-(2-amino-3- mercaptopropyl)-L-tert-leucyl]-1,2,3,4-tetrahydro-3- isoquinolinyl]carbonyl]-L-methionine methyl ester for antitumor activity in an athymic mouse model implanted ip with H-ras-transformed rat-1 tumor cells. When administered by injection twice a day at 45 mg/kg for 11 consecutive days, both compounds showed prolonged survival time (T/C = 142-145%), thus demonstrating efficacy against ras oncogene-containing tumors in vivo.
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What constitutes adequate sampling of palpable breast lesions that appear benign by clinical and mammographic criteria? Diagn Cytopathol 1995; 13:473-82. [PMID: 8834323 DOI: 10.1002/dc.2840130517] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Peptide based P21RAS farnesyl transferase inhibitors: systematic modification of the tetrapeptide CA1A2X motif. Bioorg Med Chem Lett 1994. [DOI: 10.1016/s0960-894x(01)80257-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Structure of the hirulog 3-thrombin complex and nature of the S' subsites of substrates and inhibitors. Biochemistry 1992; 31:11689-97. [PMID: 1445905 DOI: 10.1021/bi00162a004] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The X-ray crystallographic structure of the human alpha-thrombin complex with hirulog 3 (a potent, noncleavable hirudin-based peptide of the "hirulog" class containing a beta-homoarginine at the scissile bond), which is isomorphous with that of the hirugen-thrombin crystal structure, was solved at 2.3-A resolution by starting with a model for thrombin derived from the hirugen-thrombin complex and was refined by restrained least squares methods (R = 0.132). Residues of hirulog 3 were well-defined in the electron density, which included most of the pentaglycine linker and the C-terminal helical turn that was disordered in a related structure of thrombin with hirulog 1. The interactions of D-Phe1'-Pro2'-beta-homoArg3' with the active site of thrombin were essentially identical to those of related structures of PPACK- (D-Phe-Pro-Arg chloromethyl ketone) and hirulog 1-thrombin, with the guanidinium function of the arginyl P1 residue forming a hydrogen-bonding ion pair with Asp189 of the S1 site. A noticeable shift in the CA atom of beta-homoArg3' due to the methylene insertion displaces the scissile bond from attack by Ser195, thus imparting proteolytic stability to the beta-homoArg hirulog derivative. Resolution of the pentaglycine spacer, linking N- and C-terminal functional domains into a single oligopeptide bivalent inhibitor, permitted delineation of corresponding S' subsites of thrombin. The position of Gly4' (P1') is stabilized by three hydrogen bonds with His57, Lys60F, and Ser195, while the conformational angles maintained in a strained, nonallowed configuration for non-glycyl amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)
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Multidisciplinary home rehabilitation. A practical model. Clin Geriatr Med 1991; 7:695-706. [PMID: 1760789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The home is the most natural setting for rehabilitation. At home, the patient and family become active team members and the plan of care is created and carried out in the environment in which the patient will live. Home rehabilitation enhances the patient's autonomy, independence, and community reintegration.
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Abstract
Using the natural protein hirudin as a model, a novel class of synthetic peptide inhibitors were recently designed. These inhibitors, 'hirulogs', retain the carboxy terminal Hir53-64 domain that interacts with the anion binding exosite of thrombin, connected via an oligoglycyl spacer unit to a catalytic site-directed moiety modeled on the sequence [D]Phe-Pro-Arg-X. The scissile Arg-X bond bond of substrate-like inhibitors has been modified to the proteolytic-resistant functions as beta-homo amino acids Arg psi [CH2CONH] X (2) and reduced bond analogues Arg psi [CH2N]X (3). Both classes of compounds demonstrate inhibition of thrombin amidolytic activity, and this active-site inhibition is highly sensitive to the P1' residue X. Thus these hirulog derivatives are resistant to thrombin proteolysis while maintaining substrate-like interactions with the active center. Finally, hirulog derivatives with non-cleavable replacements of the scissile bond are found to be effective anticoagulant agents.
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Abstract
The binding of [3H] 8-OH-DPAT to membrane-bound 5-HT1A receptors from bovine hippocampus was saturable and corresponded to a single high-affinity state. Solubilization of the bovine hippocampal membranes with 10 mM CHAPS containing 200 mM NaCl, renders a preparation which binds [3H] 8-OH-DPAT with high-affinity (Kd = 1.9 nM) and is guanine nucleotide sensitive and ketanserin insensitive. 50% of [3H] 8-OH-DPAT binding activity is solubilized. The presence of GMP-P(NH)P promotes a low-affinity (Kd = 9.6 nM) state which is characteristic of receptors coupled to G-proteins. GMP-P(NH)P markedly accelerates the dissociation [3H] 8-OH-DPAT from solubilized membranes while having negligible effects on association. Thus, the agonist can activate the terniary complex rather than to promote its formation. 8-OH DPAT, WB 4101 and 5-carboxamidotryptamine dose responsively inhibit soluble [3H] 8-OH-DPAT binding with IC(50) values of 16.1, 15.6 and 1.3 nM, respectively. The CHAPS solubilized membrane preparation retains many of the [3H] 8-OH-DPAT binding characteristics of the membrane bound form.
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Lophotoxin and related coral toxins covalently label the alpha-subunit of the nicotinic acetylcholine receptor. J Biol Chem 1988; 263:18568-73. [PMID: 2903863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Lophotoxin and lophotoxin analog-1 are uncharged cyclic diterpenes obtained from gorgonian corals. They have been shown to block the function of nicotinic acetylcholine receptors. Inhibition results from blockade of the agonist recognition site and appears irreversible in that extensive washing does not restore receptor function. This study was undertaken to determine whether this apparently irreversible inhibition involves covalent labeling at a selective site and to further characterize this site directly. Incubation of membranes prepared from the electric organ of Torpedo californica with analog-1 followed by reduction with NaB3H4 resulted in the incorporation of radioactivity into several membrane proteins. The incorporation of radioactivity into the alpha-subunit of the receptor was blocked by prior incubation with agonists and antagonists. [3H]Lophotoxin and [3H]analog-1 were prepared by reduction with NaB3H4 and back-oxidation with CrO3. The radiolabeled coral toxins reacted selectively and covalently with the alpha-subunit of the receptor. Their binding was prevented by prior exposure to agonists and antagonists. In contrast to the site-directed alkylating agent 4-(N-maleimido)benzyltrimethylammonium iodide, prior reduction of the receptor was not required for covalent binding of 3H-labeled coral toxins. Selective reduction of Cys192 and Cys193 followed by alkylation with 4-(N-maleimido)benzyltrimethylammonium iodide blocked the binding of [3H]analog-1, whereas alkylation with iodoacetic acid or iodoacetamide did not. Thus, the binding site for the coral toxins does not overlap the binding surface near Cys192 and Cys193. Digestion of isolated labeled alpha-subunits with endoglycosidase H revealed that the polypeptide portion of the protein retained the covalently bound [3H]analog-1. Digestion with staphylococcal V8 protease revealed two major peptides of approximately 19 and 20 kDa, along with several smaller peptides. Only the 20-kDa peptide retained the covalently bound [3H]analog-1, localizing the site of covalent attachment between Ser173 and Glu335. The unique chemical structure and covalent reactivity of these gorgonian coral toxins will undoubtedly allow further insights into the structure of the agonist recognition site.
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9.4 T imaging studies of human tumor xenografts in nude mice. Invest Radiol 1988; 23:677-9. [PMID: 3182215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
To evaluate the potential of 9.4 T imaging in distinguishing normal and neoplastic tissues, we examined the progressive growth of human colon and prostate adenocarcinoma xenografts in nude mice. Images were obtained with a resolution of 100 X 100 X 650 micron, and tumors were clearly distinguished from normal tissue with high contrast. These results demonstrate the feasibility of detecting small human tumors in live nude mice with microscopic resolution at 9.4 T.
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Clonal analysis of the malignant properties of B16 melanoma cells treated with the DNA hypomethylating agent 5-azacytidine. Clin Exp Metastasis 1988; 6:185-200. [PMID: 2450714 DOI: 10.1007/bf01782479] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The role of DNA methylation in the generation of tumor cell variants with altered growth behavior has been investigated. Cultures of the clonally heterogeneous B16 melanoma cell line and a clonal population (B16-CL) derived from it were treated with the DNA hypomethylating agent, 5-azacytidine (5-Aza-CR). The tumorigenic and metastatic properties of (sub)clones isolated from these cultures before and after drug treatment were assayed by injection via multiple routes into syngeneic C57BL/6 mice using a range of cell doses. The rate of tumor growth was monitored following intrafootpad (i.f.p.) injection and the tumor incidence was calculated from the frequency of tumor formation at i.f.p. and supraclavicular subcutaneous (s.c.) sites. Formation of both spontaneous (i.f.p., s.c. inoculations) and experimental (intravenous (i.v.) inoculation) metastatic potential was also investigated. The most consistent effect of 5-Aza-CR was the introduction of heterogeneity with respect to the tumorigenic phenotype. The effect of 5-Aza-CR treatment on metastatic behavior was variable. The majority of tumor cell variants that arose following 5-Aza-CR treatment displayed decreased malignant potential and reduced DNA methylation levels relative to untreated control cells, but the correlation was not absolute. The decreases in DNA methylation levels induced by 5-Aza-CR were unstable and began to rebound within 1 week of drug treatment. The results of the current study indicate that although 5-Aza-CR can introduce significant shifts in the malignant properties of treated cells, the direction and magnitude of the induced alterations are not predictable and are influenced by a variety of experimental parameters including the starting tumor cell population, route of tumor cell inoculation, and the drug treatment protocol. In addition, because DNA methylation levels can rebound rapidly (days) it is difficult to correlate changes in this parameter with the observed alterations in malignancy, which can only be assessed in long-term biological assays (weeks).
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Abstract
To establish well-characterized cellular reagents for the study of colon carcinoma, we have examined 19 human colorectal carcinoma cell lines with regard to morphology, ultrastructure, expression of tumor-associated antigens, proliferative capacity in vitro, anchorage-independent growth, oncogene expression, tumorigenicity and malignant potential. Cell lines examined were cultured under identical conditions, and in vitro and in vivo analyses were performed in parallel on replicate cultures. Three classes of colorectal cell lines were defined according to their tumorigenicity in nude mice. Class-1 lines formed rapidly progressing tumors in nearly all mice at an inoculum of 10(6) cells. Cell lines belonging to class-2 were less tumorigenic, producing tumors later and at a slower growth rate. Class-3 lines were non-tumorigenic under all experimental conditions tested. By Northern analysis, the oncogenes c-myc, H-ras, K-ras, N-ras, myb, fos and p53 were expressed in nearly all cell lines examined. In contrast, transcripts for abl, src and ros were not detected. The best in vitro predictor of tumorigenicity was colony formation in soft agar. There was no detectable correlation between tumorigenicity and metastatic potential, doubling time in vitro, production of tumor-associated markers, xenograft histology or expression of specific oncogenes.
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Measurement of imidazoleacetic acid in urine by gas chromatography-mass spectrometry. JOURNAL OF CHROMATOGRAPHY 1985; 343:249-57. [PMID: 4066869 DOI: 10.1016/s0378-4347(00)84595-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Imidazoleacetic acid (IAA), a histamine and histidine metabolite, was quantified in human urine by gas chromatography-mass spectrometry (GC-MS). The acid was separated by ion-exchange chromatography, derivatized as the n-butyl ester with boron trifluoride-butanol and the derivative extracted with chloroform. GC-MS analysis was carried out by selected-ion monitoring of ions m/z 81 and m/z 83 corresponding, respectively, to IAA and [15N,15N']IAA used as internal standard. The mean IAA content in urine was about 8.02 nmol/mg of creatinine. The specificity of measurement was rigorously established by GC retention time, peak shape, ion abundance ratios, and recovery experiments. The method is capable of quantifying IAA in 0.05 ml of urine and in amounts as low as 0.20 nmol.
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Tumorigenic and metastatic properties of "normal" and ras-transfected NIH/3T3 cells. Proc Natl Acad Sci U S A 1985; 82:3698-701. [PMID: 3858844 PMCID: PMC397854 DOI: 10.1073/pnas.82.11.3698] [Citation(s) in RCA: 127] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
To investigate the role of oncogene activation in the pathogenesis of malignant tumors, we have studied the tumorigenic and metastatic properties of NIH/3T3 secondary transfectants (designated A51) containing an activated c-Ha-ras-1 gene derived from the human T24 bladder carcinoma cell line and compared them with untransfected NIH/3T3 cells. Whereas subcutaneous implantation of NIH/3T3 cells in the supraclavicular region produced palpable tumors that failed to metastasize, NIH/3T3 cells inoculated in the footpad gave rise to malignant tumors that metastasized to the lung. Under identical conditions and irrespective of the site of implantation, A51 cells formed rapidly growing primary tumors that produced pulmonary metastases. In an assay for experimental metastasis, intravenously injected NIH/3T3 cells gave rise to pulmonary nodules only at high cell inocula and in long-term survivors (90 days after injection). In contrast, A51 cells formed multiple lung tumor colonies detectable 14 days after injection. These results indicate that "normal" untransfected NIH/3T3 cultures contain subpopulations of cells that express malignant properties and that transfection of NIH/3T3 cells with activated c-Ha-ras-1 accelerates formation of metastases.
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A rhodopsin is the functional photoreceptor for phototaxis in the unicellular eukaryote Chlamydomonas. Nature 1984; 311:756-9. [PMID: 6493336 DOI: 10.1038/311756a0] [Citation(s) in RCA: 225] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Rhodopsin is a visual pigment ubiquitous in multicellular animals. If visual pigments have a common ancient origin, as is believed, then some unicellular organisms might also use a rhodopsin photoreceptor. We show here that the unicellular alga Chlamydomonas does indeed use a rhodopsin photoreceptor. We incorporated analogues of its retinal chromophore into a blind mutant; normal photobehaviour was restored and the colour of maximum sensitivity was shifted in a manner consistent with the nature of the retinal analogue added. The data suggest that 11-cis-retinal is the natural chromophore and that the protein environment of this retinal is similar to that found in bovine rhodopsin, suggesting homology with the rhodopsins of higher organisms. This is the first demonstration of a rhodopsin photoreceptor in an alga or eukaryotic protist and also the first report of behavioural spectral shifts caused by exogenous synthetic retinals in a eukaryote. A survey of the morphology and action spectra of other protists suggests that rhodopsins may be common photoreceptors of chlorophycean, prasinophycean and dinophycean algae. Thus, Chlamydomonas represents a useful new model for studying photoreceptor cells.
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Abstract
C3 production was assayed using an enzyme-linked immunosorbent assay (ELISA) in cell-free supernatants harvested from thioglycollate-elicited macrophages exposed to a variety of macrophage stimulating and activating agents. Macrophage monolayers treated with the stimulating agents starch, glycogen, and zymosan secreted three- to four-fold less C3 (mean 12 ng/10(5) cells/12 hr) than macrophages exposed to lymphokines containing macrophage-activating factor (MAF) (mean C3 production 44 ng/10(5) cells/12 hr). The increased production of C3 in macrophages exposed to MAF parallels the ability of these macrophages to acquire tumoricidal capacity as monitored in an in vitro 72 hr tumor cell cytotoxicity assay using B16 melanoma cells. Macrophages previously rendered tumoricidal by exposure to MAF and which are refractory to further challenge by MAF following decay of their tumoricidal properties, do not produce C3 on rechallenge with MAF. Exposure of refractory macrophages to liposome-encapsulated MAF overcomes the refractory state and induces re-expression of the tumoricidal phenotype and C3 production. We conclude that quantitative detection of macrophage-generated C3 antigen provides a useful biochemical marker for monitoring the acquisition of tumoricidal properties in macrophages exposed to MAF and offers a sensitive assay for screening novel agents that activate macrophages via mechanisms similar to MAF.
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Hospital breaks new ground with hybrid financing package. TRUSTEE : THE JOURNAL FOR HOSPITAL GOVERNING BOARDS 1984; 37:21-2. [PMID: 10264904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
By applying financial management techniques that are more traditionally associated with corporate businesses, an Illinois hospital was able to generate the funds needed for a new replacement facility at a time when the money market was especially tight. The authors explain the structure of the hybrid financing package they used, and how such a strategy enabled the hospital to generate $61 million in capital at an interest rate almost 5 percent below prime.
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