Event Analysis (event + analysis)

Distribution by Scientific Domains

Selected Abstracts

Optimization of a flow cytometry-based protocol for detection and phenotypic characterization of multipotent mesenchymal stromal cells from human bone marrow

CYTOMETRY, Issue 6 2006
Elena A. Jones
Abstract Background: To study the biology of rare bone marrow (BM) multipotent mesenchymal stromal cells (MSCs), recognized protocols are needed. Colony-forming unit-fibroblast (CFU-F) assays have historically been used for the enumeration of MSCs. However, the need to isolate and further analyze MSCs requires new strategies based on cell surface markers. The purpose of this work was to verify the phenotype of BM MSCs in vivo and to develop flow cytometry-based methods for their evaluation. Methods: Pre-enrichment with D7-FIB-conjugated microbeads, cell sorting for CD45lowD7-FIB+LNGFR+ cells, and CFU-F assay were used to confirm the phenotype of BM MSCs in vivo. Further phenotypic characterization of MSCs was performed using three-color flow cytometry following pre-enrichment or by direct four-color flow cytometry. The sensitivity of direct flow cytometry/rare event analysis for the accurate enumeration of MSCs was validated using 85 samples from patients with neoplastic BM diseases. Results: In normal BM, a significant correlation was found between the frequencies of CFU-Fs and CD45lowD7-FIB+LNGFR+ cells (n = 19, R = 0.719, P = 0.001). Following cell sorting, ,15% of these cells were clonogenic. The same cells were enriched using LNGFR-based positive selection, CD45/Glycophorin A-based depletion, or plastic adherence. CD45lowD7-FIB+LNGFR+ cells expressed classic makers of cultured MSCs CD73/SH3 and CD105/SH2 and markers of stromal reticular cells CD106/VCAM and alkaline phosphatase. Novel markers were identified including leukemia inhibitory factor receptor and gp130. CD45lowD7-FIB+LNGFR+ cells were increased fourfold in the floating fat fraction of normal BM aspirates. Their frequency was decreased in chronic lymphocytic leukemia (threefold, n = 13, P = 0.049) and chronic myelogenous leukemia (ninefold, n = 11, P = 0.001) compared with that in age-matched controls (n = 26 and n = 31, respectively). Conclusions: This study demonstrates the usefulness of flow cytometry-based methods for the detection, enumeration and further phenotypic analysis of BM MSCs. These findings have broad applications for the future evaluation of BM MSCs in health and disease. 2006 International Society for Analytical Cytology [source]

Efficacy of ibandronate for the treatment of skeletal events in patients with metastatic breast cancer

HERAS P., KRITIKOS K., HATZOPOULOS A. & GEORGOPOULOU A.-P. (2009) European Journal of Cancer Care Efficacy of ibandronate for the treatment of skeletal events in patients with metastatic breast cancer Patients with breast carcinoma often develop bone metastases that carry a high risk of complications. A randomized, placebo-controlled trial was conducted to evaluate the efficacy and safety of ibandronate in patients with metastatic bone disease following breast cancer. The primary efficacy end point of the study was the proportion of patients who developed skeletal-related events (SREs, defined as pathologic fracture, spinal cord compression, radiation therapy to bone, change in anti-neoplastic therapy and surgery to bone). Secondary end points included time to first skeletal event, skeletal morbidity rate (events/year) and time to progression of bone lesions. In 150 patients (148,/2,) with breast carcinoma and bone metastases, treatment with intravenous ibandronate 6 mg over 15 min every 4 weeks for 24 months significantly reduced the proportion of patients who experienced an SRE compared with placebo (36% vs. 48%; P = 0.027). Time to first SRE was also delayed significantly (median 457 vs. 304 days; P = 0.007). Multiple event analysis showed that ibandronate reduced the risk of developing an SRE by 32% (hazard ratio = 0.69; 95% confidence interval 0.42,0.79; P = 0.003). In general, ibandronate was well tolerated with very rare grade 3 or 4 toxicity. In this study, ibandronate was shown to be significantly more effective than placebo as a treatment for metastatic bone disease from breast cancer using multiple end points. [source]

Serially concatenated continuous phase modulation with symbol interleavers: performance, properties and design principles

Ming Xiao
Serially concatenated continuous phase modulation (SCCPM) systems with symbol interleavers are investigated. The transmitted signals are disturbed by additive white Gaussian noise (AWGN). Compared to bit interleaved SCCPM systems, this scheme shows a substantial improvement in the convergence threshold at the price of a higher error floor. In addition to showing this property, we also investigate the underlying reason by error event analysis. In order to estimate bit error rate (BER) performance, we generalise traditional union bounds for a bit interleaver to this non-binary interleaver. For the latter, both the order and the position of permuted non-zero symbols have to be considered. From the analysis, some principal properties are identified. Finally, some design principles are proposed. Our paper concentrates on SCCPM, but the proposed analysis methods and conclusions can be widely used in many other systems such as serially concatenated trellis coded modulation (SCTCM) et cetera. Copyright 2006 AEIT [source]

Workplace-based assessment for general practitioners: using stakeholder perception to aid blueprinting of an assessment battery

Douglas J Murphy
Context, The implementation of an assessment system may be facilitated by stakeholder agreement that appropriate qualities are being tested. This study investigated the extent to which stakeholders perceived 8 assessment formats (multiple-choice questions, objective structured clinical examination, video, significant event analysis, criterion audit, multi-source feedback, case analysis and patient satisfaction questionnaire) as able to assess varying qualities of doctors training in UK general practice. Methods, Educationalists, general practice trainers and registrars completed a blueprinting style of exercise to rate the extent to which each evaluation format was perceived to assess each of 8 competencies derived primarily from the General Medical Council document Good Medical Practice. Results, There were high levels of agreement among stakeholders regarding the perceived qualities tested by the proposed formats (G = 0.82,0.93). Differences were found in participants' perceptions of how well qualities were able to be assessed and in the ability of the respective formats to test each quality. Multi-source feedback (MSF) was expected to assess a wide range of qualities, whereas Probity, Health and Ability to work with colleagues were limited in terms of how well they could be tested by the proposed formats. Discussion, Awareness of the perceptions of stakeholders should facilitate the development and implementation of workplace-based assessment (WPBA) systems. These data shed light on the acceptability of various formats in a way that will inform further investigation of WPBA formats' validity and feasibility, while also providing evidence on which to base educational efforts regarding the value of each format. [source]

Increased risk of hip fracture in the elderly associated with prochlorperazine: is a prescribing cascade contributing?,

Gillian E. Caughey
Abstract Purpose To examine the prescribing of prochlorperazine secondary to the prescribing of a medicine which could lead to symptoms for which prochlorperazine is indicated and commonly used. Given the range of potential hypotensive, sedative, dystonic and other extra-pyramidal side effects associated with prochlorperazine, its association with hip fracture was also examined. Methods Prescription/event sequence symmetry analyses were undertaken from 1st January 2003 to 31st December 2006, using administrative claims data from the Department of Veterans' Affairs, Australia. This method assesses asymmetry in the distribution of an incident event (either prescription of another medicine or hospitalization) before and after the initiation of prochlorperazine. Crude and adjusted sequence ratios (ASR) with 95% confidence intervals (CI) were calculated. Results A total of 34,235 persons with incident use of prochlorperazine were identified during the study period. Statistically significant positive associations were found for a number of commonly used medicines, including cardiovascular medicines, NSAIDs, opioids and sedatives and the subsequent initiation of prochlorperazine that ranged from 1.07 (95%CI 1.01,1.14) for diuretics to 1.50 (95%CI 1.40,1.61) for statins. Prescription event analysis showed a 49% (95%CI 1.19,1.86) increased risk of hospitalisation for hip fracture following dispensing of prochlorperazine. Conclusions Prescribers should consider the possible contributing role of newly initiated medicines with the potential to cause of dizziness, and where possible address this through dose reduction or cessation of the medicine, rather than prescribing prochlorperazine. Copyright 2010 John Wiley & Sons, Ltd. [source]

The Scottish Audit of Surgical Mortality: a review of areas of concern related to anaesthesia over 10 years

ANAESTHESIA, Issue 12 2009
H. J. McFarlane
Summary The Scottish Audit of Surgical Mortality is a voluntary, peer reviewed, critical event analysis of patients who die under the care of consultant surgeons in acute hospitals in Scotland. The anaesthetic contribution to surgical mortality over a 10-year period from 1996 was reviewed. The total number of deaths was 44 230 or 1.5% of all admissions. Forty thousand, eight hundred and ninety-six deaths (92%) were audited. Deaths after elective surgery declined over 10 years. Over 80% of deaths followed emergency admission. The number of deaths where an anaesthetist was present was 16 981 or 0.6% of all admissions. Anaesthetic areas of concern were identified in 8% of deaths. Of these, 43% were related to pre-operative assessment. Anaesthesia also played a part in a further 18% of deaths where decision making was shared with the surgical team. Of these, 41% were related to access to critical care. A further 24% related to communication failures, principally when the operation should not have been done or was unnecessary. [source]

Zoledronic acid delays the onset of skeletal-related events and progression of skeletal disease in patients with advanced renal cell carcinoma

CANCER, Issue 5 2003
Allan Lipton M.D.
Abstract BACKGROUND The objective of this study was to assess the efficacy and safety of zoledronic acid in patients with bone metastases secondary to renal cell carcinoma (RCC). METHODS A retrospective subset analysis of patients with RCC enrolled in a multicenter, randomized, placebo-controlled study of zoledronic acid was performed. Patients were randomized to receive zoledronic acid (4 or 8 mg as a 15-minute infusion) or placebo with concomitant antineoplastic therapy every 3 weeks for 9 months. The primary efficacy analysis was the proportion of patients with one or more skeletal-related events (SREs), which were defined as pathologic fracture, spinal cord compression, radiation therapy, or surgery to bone. Secondary analyses included time to first SRE, skeletal morbidity rate (events per year), disease progression, and multiple event analysis. RESULTS In this subset of 74 patients with RCC, zoledronic acid (4 mg) was found to significantly reduce the proportion of patients with an SRE (37% vs. 74% for placebo; P = 0.015). Similarly, zoledronic acid significantly reduced the mean skeletal morbidity rate (2.68 vs. 3.38 for placebo; P = 0.014) and extended the time to the first event (median not reached vs. 72 days for placebo; P = 0.006). A multiple event analysis demonstrated that the risk of developing an SRE was reduced by 61% compared with placebo (hazard ratio of 0.394; P = 0.008). The median time to progression of bone lesions was significantly longer for patients who were treated with zoledronic acid (P = 0.014 vs. placebo). Zoledronic acid appeared to be well tolerated; the most common adverse events in all treatment groups included bone pain, nausea, anemia, and emesis. CONCLUSIONS Zoledronic acid (4 mg as a 15-minute infusion) demonstrated significant clinical benefit in patients with bone metastases from RCC, suggesting that further investigation of zoledronic acid in this patient population is warranted. Cancer 2003;98:962,9. 2003 American Cancer Society. DOI 10.1002/cncr.11571 [source]