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Biomedical subjects

J T Barr

Publications and source records attributed to J T Barr.

66 records · Page 4Linked to original sources
PubMed1980

Corneal thickness changes with extended contact lens wear.

Eight myopic patients wearing Permalens contact lenses continuously for 18 months were monitored for corneal thickness changes. The averaged results showed maximum corneal swelling after 1 week of wear with the cornea gradually returning to near prefitting thickness levels. However, great individual variation in corneal thickness response was noted with some patients showing chronic corneal thickening and some showing corneal thinning after the 18-month wearing period.

Contact Lenses↗
PubMed1979

Evaluation of blood culture procedures in a pediatric hospital.

To determine optimal clinical laboratory techniques for detecting pediatric bacteremia, we studied 7,768 consecutive blood cultures in a 1-year period. Blood was inoculated into one vented 50-ml bottle of brucella broth with 0.05% sodium polyanetholsulfonate and one unvented 50-ml bottle of Columbia broth with 0.05% sodium polyanetholsulfonate and 0.05% cysteine. Bottles were visually examined for growth on days 1 through 7 and blindly subcultured aerobically and anaerobically on days 1, 2, and 7. There were 724 (9.3%) positive cultures, and 484 (6.2%) were clinically significant. The most frequent isolates from bacteremic patients were Haemophilus influenzae (24%) and Streptococcus pneumoniae (17%). Growth was noted in only one bottle in 25% of clinically significant isolates. Bottles inoculated with greater than or equal to 1 ml of blood became positive earlier than bottles inoculated with less than 1 ml. After 1 day of incubation, 48% of the clinically significant cultures showed growth on visual examination, whereas 85% showed growth on subculture. Only 19% of Haemophilus isolates were detected visually on day 1, whereas 88% were recovered on subculture. By day 7, 3.5% of all isolates (including 18% of pneumococcal isolates and 1% of Haemophilus isolates) could no longer be recovered on subculture. We conclude that a two-bottle blood culture system and blind subculture within 24 h will optimize detection of pediatric bacteremia.

Bacteria↗
PubMed1979

A ladder curriculum in clinical microbiology.

A continuum of four microbiology courses for medical technology majors has been developed by the Medical Laboratory Science Program at Northeastern University. Using a system approach to curriculum design, the academic and clinical faculty identified career-entry capabilities, delineated appropriate subject content, and developed an instructional system which placed individual topics into one of four courses in the ladder curriculum: a basic, second-year, university-based clinical microbiology course stressing microbial technique and common organism identification; third-year microbiology and cellular physiology courses developing theoretical aspects; a fourth-year, hospital-based clinical microbiology rotation emphasizing isolation and identification techniques for significant pathogens; and a fourth-year, university-based, didactic course covering host defense-organism virulence interactions, infectious disease principles, and new techniques and unusual isolates as reported in the recent journal literature. Based on four years of experience with this system and in light of the publication of the 1978 American Society for Medical Technology (ASMT) Competency Statements, the Northeastern Medical Laboratory Science Program faculty is currently reexamining the continuum to insure completeness and appropriateness of overall subject content, to provide reinforcement, and to remove unnecessary duplication among the courses in the curriculum.

Certification↗
PubMed1977

Measured and laboratory-stated parameters of hydrophilic contact lenses.

One hundred thirty-one new hydrophilic lenses made by 3 manufacturers were randomly selected from an optometry clinic for measurement and inspection. Approximately 60% of the base-curve specifications fell within the following ranges for the measured dimensions: Bausch & Lomb Soflens contact lenses, less than 0.150 mm; Milton Roy Naturvue lenses, less than 0.375 mm; Soft Lens Inc. Hydrocurve, less than 0.225 mm. More than 65% of the lenses supplied by all the manufactures were within 0.25 D of the power specification. About two-thirds or more of all lenses had a central thickness and overall diameter within 0.04 mm and 0.40 mm, respectively, of the manufacturers' specifications, although there were notable differences among manufacturers. Most of these new lenses exhibited surface scratches and other surface defects, and many lenses had edge defects.

Contact Lenses, Hydrophilic↗
PubMedDate not supplied

Photodocumentation of corneal scarring. Collaborative Longitudinal Evaluation of Keratoconus Study Group.

PURPOSE: A standardized system for photodocumenting corneal scars and for evaluating these photographs does not exist and is essential for clinical research. To address this need, we developed a system for photographing and evaluating corneal scars. METHODS: In the "Development Phase," we tested several procedures in small samples totaling 40 eyes of 20 keratoconus patients. In the "Test Phase," we used an independent sample of 150 eyes of 82 keratoconus patients. Fifty-nine of these 150 eyes had corneal scars, and 91 of the eyes did not as determined by the clinician. RESULTS: The photography protocol requires four central parallelepiped and two whole cornea oblique photographs after pupil dilation. With the clinician as gold standard, this technique yielded sensitivity of 96% and specificity of 83%. Evaluation of the corneal photographs as to the presence or absence of corneal scarring was performed independently by two masked readers. Agreement between clinicians on the presence of corneal scarring was 0.99 (kappa); agreement between readers for the presence of scarring was 0.80 (kappa). CONCLUSIONS: The corneal photography protocol we describe is recommended for use in clinical investigations of cicatricizing corneal disease and appears robust enough to be used in multicenter studies.

Corneal Diseases↗
PubMedDate not supplied

The total testing process and its implications for laboratory administration and education.

The Total Testing Process is a multistep process that begins and ends with the needs of the patient. Identifying the many steps in the Total Testing Process and planning and using an interdisciplinary team to begin a coordinated effort will improve the process and offer optimal patient care. Communication among departments and developing interdepartmental guidelines will improve the use, sampling, performance, and interpretation of health assessment procedures. A commitment to the continuous improvement of patient assessment will require the participation of numerous health professionals. It is time for every institution to bring individuals together, collectively identify solutions, implement an improvement plan, and evaluate the effectiveness of their efforts using outcome measures that both directly and indirectly relate to improved patient care. Doing it right the first time will benefit the patient and conserve our limited health-care dollars.

Accreditation↗
PubMedDate not supplied

Development of a quantitative weighted scoring instrument to evaluate bedside blood glucose testing programs.

The present assessment of laboratory quality is primarily a qualitative summary process. The objective of our study is to convert a qualitative standards document into a quantitative, weighted scoring system. We selected a laboratory testing standards document, Ancillary (Bedside) Blood Glucose Testing in Acute and Chronic Care Facilities, C30, developed by the National Committee for Clinical Laboratory Standards (NCCLS), as our prototype and used a two-stage, modified delphi technique. Sixty-nine criteria were identified from the C30 document. Using a two-stage, modified delphi technique, members of the NCCLS committee that developed the guideline weighted the relative importance of each criteria. This weighting system then was used to evaluate the quality of bedside glucose testing at the 14 general hospitals located within the city limits of Boston.

Blood Glucose↗
PubMedDate not supplied

Bayesian approaches in pharmacokinetic decision making.

The theory of Bayesian analysis and its application to therapeutic and pharmacokinetic decision making are discussed. Diagnostic and therapeutic decisions are commonly based on institution, experience, and laboratory information; these decisions reflect varying degrees of uncertainty. Bayesian analysis quantifies the decision process by attaching probabilities to the likelihood of accuracy of each of these decision-making factors to achieve an overall estimate of decision quality. Using Bayesian principles to quantify the probability of efficacy and toxicity associated with serum drug concentrations represents one application of Bayesian theory to enhance therapeutic decisions. The Bayesian approach in pharmacokinetics involves the prediction of pharmacokinetic values, dosage regimens, and serum concentrations for drugs. Beginning with mean population pharmacokinetic parameters, one uses observed serum concentrations in individual patients to modify these parameters through Bayesian analysis to improve the accuracy of future serum concentration predictions. As more clinical pharmacokinetic laboratories and consultation services become familiar with the procedure, Bayesian forecasting promises to expand markedly the sophistication of therapeutic drug monitoring.

Decision Making↗