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Biomedical subjects

G C Burke

Publications and source records attributed to G C Burke.

At least 19 recordsLinked to original sources
PubMed2001

Analysis of acetic acid-induced whitening of high-grade squamous intraepithelial lesions.

Immature and dysplastic cervical squamous epithelium whitens after the application of acetic acid during a colposcopic examination. The whitening process occurs visually over several minutes and subjectively discriminates between dysplastic and normal tissue. In this work, examples of the acetowhitening process are detailed in three ways: the color-imaged colposcopic appearance of the acetowhitening of high-grade cervical intraepithelial neoplasia (CIN 2/3), the kinetics of these reflectance patterns transformed to reduce noise in the signal, and a self-normalized green to red ratio measurement of the kinetics of these reflectance patterns. A total of six patients with biopsy confirmed CIN 2/3 were examined to obtain a set of timed images tracking the acetowhitening and the whitening-decay process over the course of 5-10 min. Regions of normal mature squamous epithelium within the same patients were also followed as an internal control. We determined that the temporal change over a 10 min time period in the ratio of green to red light intensities, taken from the respective color channels of the CCD, provides a reliable measure to clearly distinguish CIN 2/3 from normal cervical epithelium. This imaging and data normalization procedure may be applied to cervical lesions of different grades, to determine if a quantitative estimate provides predictive value during the colposcopic diagnosis.

Acetic Acid↗
PubMed2001

Comparison of photosensitizer (AIPcS2) quantification techniques: in situ fluorescence microsampling versus tissue chemical extraction.

A noninvasive in situ fluorescence-based method for the quantification of the photosensitizer chloroaluminum disulfonated phthalocyanine was compared to the highly accurate but nonreal time ex vivo spectrofluorometry method. Our in vivo fluorescence technique is designed to allow real-time assessment of photosensitizer in tumor and normal tissues and therefore temporally optimal light delivery. Laser-induced fluorescence was used to measure photosensitizer concentration from multiple microscopic regions of tissue. Ex vivo chemical extraction was used to quantify photosensitizer concentration in the same volume of tissue. The amount of photosensitizer in the vascular and/or parenchymal compartments of skeletal muscle and liver was determined by quantifying fluorescent signal in vivo, ex vivo and after blood removal. Confocal microscopy was used to spatially document photosensitizer localization 30 min and 24 h after delivery. While a linear correlation can exist between the fluorescence intensity measured by our fiber-optic bundle system and actual tissue concentration, temporal changes to this calibration line exist as the photosensitizer changes its partitioning fraction between the blood (vasculature) and the tissue parenchyma. In situ photosensitizer fluorescence microsampling (dosimetry) systems can be performed in real time and linearly correlated to actual tissue concentration with minimal intertissue variance. Tissue-specific differences may require temporal alterations in the calibration.

Animals↗
PubMed2000

The technical performance and clinical feasibility of telecolposcopy.

BACKGROUND: The purpose of our study was to demonstrate the technical performance and clinical feasibility of a telecolposcopic system through assessment of image transmission veracity, ease of office system implementation, and the patient's acceptance of the electronic image transmission. METHODS: We used a telecolposcopic system incorporating a custom software package that integrated patient history, current gynecologic status, epidemiologic risk factors, and colposcopic images for local medical documentation and transmission. Satisfaction questionnaires were developed to measure ease of implementation at the remote sites and the patients' acceptance of telecolposcopy. RESULTS: Seventy-nine women participated in our trial. From 3 to 20 images were captured for each woman, documenting cervical squamous intraepithelial lesions and vaginal and vulvar diseases. All images were received without distortions in color, size, or orientation. With complete visualization of the squamocolumnar junction there was an 86% agreement between the remote and review sites (kappa=.533, P=.019). The interobserver agreement for colposcopic impressions was 86% (kappa=.684, P <.001), and for colposcopic impressions with histology within one level of disease severity, 86% (kappa=.78, P <.001). Colposcopists' and patients' satisfaction with telecolposcopy was excellent. More than 95% of the women stated that they would rather have their colposcopy locally with electronic transmission if an experienced colposcopist were more than 25 miles away. CONCLUSIONS: The telecolposcopic system described in our study is technically feasible, can be implemented in an office system with limited technical support, and is preferred by women who have to travel many miles to receive referral health care.

Adolescent↗
PubMed1993

We've got to stop meeting like this.

Meetings are an integral aspect of healthcare management. Too often, however, they are run inefficiently and with the wrong emphases, thus diminishing their inherent value. The words of wisdom from this veteran of innumerable meetings should provide readers with some pointers on how to get their meetings back on track.

Group Processes↗
PubMed1991

Renewal and change for health care executives.

Health care executives must consider renewal and change within their own lives if they are to breathe life into their own institutions. Yet numerous barriers to executive renewal exist, including time pressures, fatigue, cultural factors, and trustee attitudes. This essay discusses such barriers and suggests approaches that health care executives may consider for programming renewal into their careers. These include self-assessment for professional and personal goals, career or job change, process vs. outcome considerations, solitude, networking, lifelong education, surrounding oneself with change agents, business travel and sabbaticals, reading outside the field, physical exercise, mentoring, learning from failures, a sense of humor, spiritual reflection, and family and friends. Renewal is a continuous, lifelong process requiring constant learning. Individual executives would do well to develop a framework for renewal in their careers and organizations.

Age Factors↗
PubMed1991

Role conflict and role ambiguity among respiratory care managers.

UNLABELLED: The health occupations and management literature does not specifically address role stress among technical directors of respiratory care departments. We undertook an analysis of role conflict, role ambiguity, and job satisfaction among technical directors of respiratory care departments in Texas. METHODS & MATERIALS: We distributed a questionnaire designed to measure role conflict and ambiguity and a questionnaire to elicit demographic and organization data to 283 technical directors in all Texas hospitals with more than 75 beds. Organization characteristics and demographic factors were studied as moderators. RESULTS: Analysis of the 199 responses received revealed that both role conflict (mean [SD] 3.86 [0.97] on 7.0 scale) and role ambiguity (2.64 [0.93] on 7.0 scale) scores were low compared to the neutral point of measure. Role overload, a component of role conflict, was found to be above the neutral point (4.64 [1.85]). One-way analysis of variance revealed no significant differences between the role conflict or the role ambiguity measures based on age, race, gender, number of employees supervised, size of institution, and position to which the respondent reported. Role conflict and role overload were each found to have significant negative correlations with job satisfaction (p less than 0.01). CONCLUSION: We are encouraged by the low role-conflict and ambiguity scores observed but concerned about the elevated role-overload scores. We believe that an in-depth study of role overload among respiratory care managers is warranted.

Adult↗
PubMed1989

Understanding the dynamic role of the hospital executive: the view is better from the top.

This article reports the findings of a study of role conflict, role ambiguity, and job dissatisfaction among 119 hospital executives in Houston and San Antonio, Texas. While other studies have looked at role descriptions, this study is the first to examine the dynamics of role conflict and ambiguity among hospital executives. A major finding was that role ambiguity and job dissatisfaction varied according to level in the organization. Chief executive officers were found to be more satisfied and to experience less role ambiguity than their subordinates. This is important to understanding better the role of the hospital executive and mentoring.

Career Mobility↗
PubMed1988

Role stress in hospital executives and nursing executives.

Two recent studies report for the first time on role stress in hospital executives--those in general administration and those in top nursing positions. Analysis reveals some similarities and differences, which provide insight into the difficult jobs of these executives.

Administrative Personnel↗
PubMed1985

Calcium in lymphotoxin-mediated cytolysis: cellular pools, fluxes, and role of extracellular concentration.

This study explores, by kinetic analysis, the movement of calcium among cellular pools of target cells in which cytotoxicity is induced by human lymphotoxin, and evaluates the requirement for calcium in this reaction. We employed the kinetic model of Borle to quantitate flux rates and pool sizes. It was found that the rate of flux between the surface (plasma membrane-glycocalyx) compartment and the intracellular compartment was greatly increased. The size of the total exchangeable intracellular calcium pool was not altered, but there was an apparent decrease in the size of the surface calcium pool. This latter phenomenon may be related to the blebbing and exfoliation of plasma membranes under the influence of the lymphokine. Lymphotoxin-induced cytotoxicity is observed in calcium-free medium and over a range of calcium concentrations. These results argue against cell death due to a massive in rush of calcium into the cell under these circumstances.

Animals↗
PubMed1979

Lymphotoxin-induced loss of plasma-membrane protein.

Lymphotoxin-sensitive L cells were prelabeled with isotopically marked leucine and exposed either to human alpha-lymphotoxin (alpha-LT) or control buffer. Plasma membranes were then isolated from these cells, and TCA-precipitable leucine was determined as a measure of membrane protein. Human alpha-LT caused a marked reduction of plasmalemmal protein in LT-sensitive target cells. This loss of protein was general, not restricted to specific fractions, as assessed by sodium dodecyl sulfate (SDS)--polyacrylamide gel electrophoresis. Since purified alpha-LT had no detectable proteolytic activity, the effect of the lymphokine is not readily explained by direct enzymatic action on plasma-membrane protein. In contrast, there was no plasma--membrane protein loss in LT-resistant target cells on exposure to alpha-lymphotoxin.

Animals↗