Biomedical subjects

David Keegan

Publications and source records attributed to David Keegan.

7 recordsLinked to original sources

PubMed2006

Young children's perceptions of physicians wearing standard precautions versus customary attire.

OBJECTIVE: The aim of the study was to determine if young children have a preference regarding whether physicians wear standard precautions attire. METHODS: One hundred ninety-seven children, aged 4 to 8 years, and their parents were recruited from the pediatric emergency department of a tertiary care center. Two sets of 4 photographs-the same man in formal attire, a white coat, greens, and severe acute respiratory syndrome (SARS) standard precautions attire, and the same woman in formal attire, a white coat, greens, and SARS standard precautions attire-were shown to the children and their caregiver. Both were asked which physician's attire he or she liked the most and which he or she liked the least. Parents filled out a questionnaire regarding their experiences in the pediatric emergency department during the SARS epidemic. RESULTS: The children selected the physician in SARS standard precautions attire as most liked 17.5% of the time and least liked 53.3% of the time. The parents selected the physician in SARS standard precautions attire as most liked 0% of the time and least liked 94.8% of the time. CONCLUSIONS: Physicians wearing standard precautions attire while working in the pediatric emergency department need to be aware that this attire may negatively impact their relationship with pediatric patients 4 to 8 years of age.

Child↗

PubMed2006

Factors explaining career satisfaction among psychiatrists and surgeons in Canada.

BACKGROUND: The career satisfaction of specialists is affected by many variables ranging from family responsibilities, stress, the quality of services and facilities available to patients, professional rewards, and how the work is organized. OBJECTIVE: To articulate models that explain a substantial portion of the variance associated with career satisfaction among surgeons and psychiatrists in Canada. METHODS: Of 4958 eligible physicians across Canada, 2810 (56.7%) completed a 12-page survey between January and March 2004, following which the responding 148 surgeons and 231 psychiatrists were selected for this study. We checked response bias and found it was negligible. Hierarchical regression analysis was used to record cumulative R2, Standardized beta, and significance levels as each predictor was entered. We applied weighting factors to reflect the actual physician population in Canada. RESULTS: The models explained 90.4% of the variance in career satisfaction for surgeons and 81.0% of the variance in career satisfaction for psychiatrists. The explanatory variables consisted of distress and coping, role in community activities, access to and quality of health care services, intrinsic and extrinsic rewards, workload, and organizational structure. CONCLUSIONS: The study demonstrated that variance associated with career satisfaction can be explained using various factors reported directly by physicians. The study also confirmed that relative differences in the importance of these factors do occur among specialties. Surgeons prefer to delegate more responsibility in the management of their practices on an informal basis, whereas psychiatrists prefer to be more involved in the management of their practices and use more formal structures.

Adaptation, Psychological↗

PubMed2006

Cornerstones of career satisfaction in medicine.

OBJECTIVES: To establish a reliable and concise measure of career satisfaction that covers all 4 of its dimensions and to document higher dimensions of satisfaction among the major medical specialties and across varying patterns of clinical practice. METHODS: In 2004, we conducted a stratified, cross-sectional survey of physicians in Canada. Of the eligible population, 2810 physicians (56.7%) responded. We checked response bias and found it was negligible. Responding physicians completed a 17-item measure of career satisfaction along with a detailed breakdown of clinical, academic, and administrative duties. We used confirmatory factor analysis to verify the existence of the hypothesized dimensions of higher-order satisfaction. We then used Scheffe's tests to document differences in the levels of all satisfaction dimensions, both among specializations and by clinical practice profile. RESULTS: Factor analysis revealed 4 reliable dimensions of satisfaction: personal (alpha = 0.85), professional (alpha = 0.78), inherent (alpha = 0.70), and performance (alpha = 0.75). Inherent satisfaction with medicine as a career was the most important dimension for all specializations and for all patterns of practice. The addition of administrative duties without a reduction of clinical duties compromised personal, professional, and performance dimensions of career satisfaction. Academic duties contributed significantly to most physicians' overall, inherent, and performance satisfaction. CONCLUSION: Distinguishing higher-order dimensions of satisfaction from basic ones is a groundbreaking finding because addressing higher-order dimensions supports self-actualization and superior performance of duties.

Canada↗

PubMed2003

Expression of brain-derived neurotrophic factor mRNA in rat hippocampus after treatment with antipsychotic drugs.

Typical and atypical antipsychotic drugs, though both effective, act on different neurotransmitter receptors and are dissimilar in some clinical effects and side effects. The typical antipsychotic drug haloperidol has been shown to cause a decrease in the expression of brain-derived neurotrophic factor (BDNF), which plays an important role in neuronal cell survival, differentiation, and neuronal connectivity. However, it is still unknown whether atypical antipsychotic drugs similarly regulate BDNF expression. We examined the effects of chronic (28 days) administration of typical and atypical antipsychotic drugs on BDNF mRNA expression in the rat hippocampus using in situ hybridization. Quantitative analysis revealed that the typical antipsychotic drug haloperidol (1 mg/kg) down-regulated BDNF mRNA expression in both CA1 (P < 0.05) and dentate gyrus (P < 0.01) regions compared with vehicle control. In contrast, the atypical antipsychotic agents clozapine (10 mg/kg) and olanzapine (2.7 mg/kg) up-regulated BDNF mRNA expression in CA1, CA3, and dentate gyrus regions of the rat hippocampus compared with their respective controls (P < 0.01). These findings demonstrate that the typical and atypical antipsychotic drugs differentially regulate BDNF mRNA expression in rat hippocampus.

Analysis of Variance↗

PubMed2002

Protective effects of atypical antipsychotic drugs on PC12 cells after serum withdrawal.

Atypical antipsychotic drugs are widely used in the treatment of schizophrenia, and clinical evidence has shown that early and prolonged intervention with these drugs will improve the long-term outcome. It is still unclear, however, whether the atypical antipsychotic drugs are also neuroprotective. To clarify this matter, we used PC12 cell cultures and the MTT assay for cell viability to determine whether various concentrations of the atypical antipsychotics clozapine, quetiapine, and risperidone are neuroprotective after serum withdrawal. In addition, to explore the drugs' actions, Northern blot was used to examine the gene expression of SOD1 (Cu/Zn superoxide dismutase) and p75NTR (p75 neurotrophin receptor). The results demonstrated that 1) the antipsychotic drugs can protect PC12 cells from death after serum withdrawal; cell viability in these drug treatment groups is significantly different from that in the groups without serum in the medium (P < 0.01); and 2) these drugs up-regulated the SOD1 gene expression to more than 120% (P < 0.05) and also down-regulated p75NTR mRNA levels to less than 65% of their respective control values (P < 0.05). These findings suggest that the atypical antipsychotics clozapine, quetiapine, and risperidone may exert a neuroprotective function through the modulation of SOD1 and p75NTR expression.

Animals↗

PubMed2002

Quetiapine attenuates the immobilization stress-induced decrease of brain-derived neurotrophic factor expression in rat hippocampus.

Quetiapine is a new atypical antipsychotic drug widely used in the treatment of schizophrenia and other psychotic disorders. This study examined the influence of quetiapine on the decrease of brain-derived neurotrophic factor (BDNF) expression, induced by chronic immobilization stress, in the hippocampus of the rat. Pretreatment with 10 mg/kg of quetiapine markedly attenuated the stress-induced decrease in levels of BDNF protein, as determined by Western blot analyses, and the reduction of BDNF immunoreactivity, in hippocampal pyramidal and dentate granular neurons. These results suggest that the chronic administration of quetiapine could be neuroprotective to hippocampal neurons in schizophrenia and this effect may be related to its antipsychotic effect in patients with schizophrenia.

Animals↗

PubMed2002

Characterization of genetically modified human retinal pigment epithelial cells developed for in vitro and transplantation studies.

PURPOSE: To develop, by specific genetic modification, a differentiated human retinal pigment epithelial (RPE) cell line with an extended life span that can be used for investigating their function in vitro and for in vivo transplantation studies. METHODS: Primary human RPE cells were genetically modified by transfecting with a plasmid encoding the simian virus (SV)40 large T antigen. After characterization, two cell lines, designated h1RPE-7 and h1RPE-116, were chosen for further investigation, along with the spontaneously derived RPE cell line ARPE-19. Factors reported to be important in RPE and photoreceptor cell function and survival in vivo were examined. RESULTS: Both h1RPE-7 and h1RPE-116 cells exhibited epithelial morphology, expressed cytokeratins, and displayed junctional distribution of ZO-1, p100-p120 and beta-catenin. The cells expressed mRNA for RPE65 and cellular retinaldehyde-binding protein (CRALBP) and the trophic and growth factors brain-derived neurotropic factor (BDNF), ciliary neurotrophic factor (CNTF), basic fibroblast growth factor (bFGF), pigment epithelium-derived factor (PEDF), nerve growth factor (NGF), platelet-derived growth factor (PDGF)-alpha, insulin-like growth factor (IGF)-1, and vascular endothelial growth factor (VEGF). Secreted BDNF, bFGF, and VEGF, but not CNTF, were identified in cell supernatants. The cell lines constitutively expressed HLA-ABC, CD54, CD58, and CD59. After activation with IFN-gamma both HLA-ABC and CD54 were upregulated, and the expression of HLA-DR was induced. Both cell lines failed to express CD80, CD86, CD40, or CD48 in vitro and in a mixed lymphocyte reaction were unable to induce T-cell proliferation. Fas ligand (CD95L) was not detected in vitro by RT-PCR. Similar results were obtained with the ARPE-19 cell line. CONCLUSIONS: RPE lines h1RPE-7 and h1RPE-116 retain many of the morphologic and biochemical characteristics of RPE cells in vivo and may serve as a source of cells for in vitro analysis of RPE cell function, as well as for orthotopic transplantation studies.

Antigens, Polyomavirus Transforming↗