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R N Taylor

Publications and source records attributed to R N Taylor.

At least 145 records · Page 8Linked to original sources
PubMed1976

Results of the Center for Disease Control Proficiency Testing Program for the detection of hepatitis B surface antigen.

The changes in the types and numbers of tests used by participants in the Center for Disease Control Proficiency Testing Program for the detection of hepatitis B surface antigen from the beginning of the program in 1971 until October 1975 are analyzed; the implications of these changes are discussed. Changes in the use of agar gel diffusion, rheophoresis, counterelectrophoresis, complement fixation, reverse passive latex agglutination, radioimmunoassay, and reverse passive hemagglutination tests are reviewed. The performance of the participants for 1975 is reported, and factors related to performance (type or combinations of tests used, procedures used to confirm specificity, etc.) are discussed. The increase in the use of third-generation tests in place of tests with lower sensitivity and the decrease in the use of multiple tests undoubtedly represent increased efficiency and effectiveness.

Blood Donors↗
PubMed1976

Evaluation of tests for infectious mononucleosis through proficiency testing.

Two standard tests for infectious mononucleosis (the Davidsohn differential and the ox cell hemolysin test) and ten slide tests; Monotest (Wampole), Monospot (Ortho), IM Kit (Micro. Res. Corp.) Monosticon (Organon), Diagluto IM (Beckman), Monosticon Dri-Dot (Organon), Bacto-Hetrol (Difco), Mono-Diff (Wampole), Monophile (Bio-Diagnostic Systems) and Rythrotox (BMC) were evaluated as they were used in 50 laboratories within the State of Utah and by two referee laboratories outside the state. The state proficiency testing program for infectious mononucleosis was modified so that the desired evaluation survey data could be obtained. Sensitivity, specificity, reproducibility (within and between shipments) and percent agreement with target results were determined for each test; factors which might have affected the test results were evaluated to determine which were correlated with good performance.

Costs and Cost Analysis↗
PubMed1975

Mites in the environment of cases of Norwegian scabies.

Three cases of Norwegian Scabies diagnosed in Glasgow hospitals within 1 year each caused wide-spread outbreaks of papular eruptions amongst the patients and staff, followed later by a few cases of classical scabies. Symptoms and timing suggested that these infections were caused by immature mites derived by personal contact and possibly by contact with infected cuticular fragments which were abundant in the environment of the three patients. To control a ward epidemic, isolation of the Norwegian scabietic should be followed by environmental and then by personal disinfestation.

Aged↗
PubMedDate not supplied

Sera from preeclamptic women specifically activate human umbilical vein endothelial cells in vitro: morphological and biochemical evidence.

Endothelial cell dysfunction could explain many of the pathophysiological changes observed in preeclampsia. Markers of endothelial cell activation including increased circulating Von Willebrand factor (VWF) and cellular fibronectin (cFN) antedate clinically evident disease. We have therefore proposed that alteration of endothelial cell function by circulating agent(s) produced by the placenta initiates the clinical syndrome. This hypothesis predicts that there are a factor(s) in the blood of women with preeclampsia that are capable of altering endothelial cell function. We and others have examined in vitro interactions of maternal serum and endothelial cells to test this hypothesis. Our initial report indicating increased release of [51Cr]chromate from human umbilical vein endothelial cells (HUVE) suggested a lethal, lytic effect of serum from preeclamptic women. However, more specific indicators of endothelial cell structure and function do not support such a nonspecific effect. The morphology of HUVE was minimally altered after exposure to sera of preeclamptic women, and the entry of propidium iodide entry into cells, a sensitive indicator of membrane integrity, also was not increased. These findings, in combination with the increased expression of mRNA for platelet-derived growth factor (PDGF), suggest endothelial cell activation rather than cell death in response to sera from preeclamptic women. Comparison of the effects of endotoxin and sera from preeclamptic women also supports the specificity of this response. Whereas endotoxin strikingly increased VWF on the surface of HUVE and tissue factor activity in conditioned media while minimally increasing cFN, preeclamptic sera increased cFN but had no demonstrable effect on VWF or tissue factor activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Capillary Permeability↗
PubMedDate not supplied

CytoView. A prototype computer image-based Papanicolaou smear proficiency test.

OBJECTIVE: To develop and assess CytoView, a prototype computer image-based cytology proficiency testing (PT) system, as an alternative to glass-slide cervical cytology PT. STUDY DESIGN: The computer-based PT consists of 10 cases taken from 10 Pap smears, each of which had received a consensus Clinical Laboratory Improvement Amendments-category diagnosis from three pathologists. Each CytoView "case" was the digital representation of > 8,000 microscopic fields, captured from a selected 5 x 10-mm rectangle of a Pap smear. The 5 x 10-mm capture rectangle was selected from the slide's most representative area for its diagnostic category. The CytoView project team developed each case through a multistep process that included image capture, image alignment, correlation of 10x and 40x images, and image display. The 10-slide CytoView PT prototype was then assessed by groups of cytopathologists and cytotechnologists. RESULTS: The CytoView prototype PT system was developed and assessed. CONCLUSION: Preliminary evaluation of CytoView indicated potential for this format as a valid and logistically feasible alternative to the traditional glass slide PT format.

Evaluation Studies as Topic↗
PubMedDate not supplied

Methods for a model blind proficiency testing system.

The method developed for establishing a blind proficiency testing (PT) system is presented. The Laboratory Assurance Program of the Graduate School of Public Health at San Diego State University is developing and pilot testing innovative strategies that will evaluate and improve the performance of clinical laboratories. To date, a total of 32 laboratories have been incorporated into this program along with 12 counseling and testing sites. From June 1988 to December 1989, five blind PT surveys for human immunodeficiency virus type 1 antibody testing were conducted, representing 306 proficiency specimens entered into the testing system as simulated patient specimens. Despite the difficulties and expense involved, we found the system to be acceptable and to have certain advantages over conventional methods of external testing.

AIDS Serodiagnosis↗
PubMedDate not supplied

Analytic results of HIV-1 testing using blind proficiency testing.

The use of blind proficiency testing (PT) to examine analytic performance of human immunodeficiency virus type 1 (HIV-1) antibody testing. A total of 32 hospital, blood bank, public health, and commercial laboratories were included in this study. Test sera were introduced as clinical specimens for HIV-1 testing from private practitioners, group practices, clinics, and hospitals in Southern California. A total of 26 laboratories were located throughout California, with six laboratories located in six other states. Results from 306 enzyme immunoassay screening tests and 192 supplemental tests for HIV-1 were reported. Although one positive specimen was reported as indeterminate in almost 30% of results, screening and supplemental testing performances were excellent, with accuracy levels comparable to performance reported on open PT and performance evaluation surveys in the United States. The indeterminate results were attributed to the interpretive criteria used rather than to laboratory errors. Blind PT can be an important tool in improving the quality of total laboratory testing, the usefulness of laboratory results in patient care, and ultimately the health of the public.

AIDS Serodiagnosis↗
PubMedDate not supplied

Use of a modified nominal group process for improving laboratory performance in human immunodeficiency virus type 1 antibody testing. Reaching consensus on three questions concerning HIV-1 testing.

Using expert panels of medical technologists and public health microbiologists, a modified nominal group process was used to reach a consensus on three questions concerning current human immunodeficiency virus type 1 (HIV-1) testing methods. The questions related to important sources of error, improving the testing process, and improving proficiency testing. The modified nominal group process proved to be effective in developing lists of errors in laboratory testing; it provided a fast, economic means of identifying possible areas for improving laboratory quality assurance and training programs. For the HIV testing model, the focus group panelists indicated laboratory pipetting errors, labeling, and specimen identification as the most important sources of error. To improve the quality of this testing, the panel recommended standardizing test interpretation and restricting testing to laboratories licensed to perform HIV-1 testing. To improve proficiency testing, the use of blind specimens and establishing minimum standards of performance were suggested.

California↗
PubMedDate not supplied

T-lymphocyte immunophenotyping blind proficiency testing: a model system for CD4+ T-cells.

OBJECTIVE: To develop and evaluate methods and results for blind proficiency testing for CD4+ T-cells by T-lymphocyte immunophenotyping. DESIGN: A model system was developed to submit duplicate specimens for T-lymphocyte immunophenotyping as if they were routine patient specimens rather than proficiency specimens. Testing results were compared both interlaboratory and intralaboratory. The model system was designed to gather information on not just the analysis, but other segments of the total testing process. SETTING: Research facilities at the Graduate School of Public Health, San Diego State University, San Diego CA. PARTICIPANTS: 1) A healthy adult volunteer donating one pint of blood. 2) Laboratories offering T-lymphocyte immunophenotyping. MAIN OUTCOME MEASURES: 1) Feasibility of blind proficiency so that PT specimens are received, analyzed, and reported by laboratories without being identified as 'proficiency specimens.' 2) The ease and cost of such a system. 3) The comparability of results and report content among laboratories. RESULTS: A total of twenty-two laboratories received blind proficiency specimens. The model developed to submit specimens and receive results proved feasible. The interlaboratory coefficient of variation for CD4+ count for the four survey years ranged from 10% to 66% and for the CD4+ percent ranged from 4% to 15%. The per specimen cost in this blind proficiency testing was $437.65, approximately seven and a half times the cost for nonblinded proficiency testing or performance evaluations. CONCLUSIONS: Blind proficiency as a tool to compare laboratory test results for T-lymphocyte immunophenotyping is feasible but adds costs. The model system is useful to examine more of the laboratory total testing process than the analysis segment.

Blood Specimen Collection↗
PubMedDate not supplied

CDC's Model Performance Evaluation Program: assessment of the quality of laboratory performance for HIV-1 antibody testing.

In 1986, the Centers for Disease Control (CDC) implemented the Model Performance Evaluation Program (MPEP) to evaluate the performance of laboratories that test for antibody directed against human immunodeficiency virus type 1 (HIV-1). The impetus for developing this program came from the recognition of a need to assess the quality of existing and changing laboratory technology and to ensure that the quality of testing was sufficient to meet medical and public health needs. To develop the program, CDC chose HIV-1 antibody testing as the first specific application for assessing the quality of laboratory performance because (a) of the importance of accurate and reproducible test results for acquired immunodeficiency syndrome (AIDS) surveillance, prevention, and treatment programs; (b) HIV-1 testing technology is new to many laboratories; and (c) HIV-1 testing practices and applications continue to evolve. Unlike proficiency testing programs, the MPEP is not limited to assessing quality in the analytical step, alone. It will also assess quality in the preanalytical and postanalytical steps of the testing process, that is, from the time a test is requested until the clinician who ordered the test takes an action based on the test result. The participating laboratories furnish the information needed for the performance evaluation program by (a) completing questionnaires designed to describe HIV-1 testing laboratories and their testing practices, (b) analyzing specially prepared sample panels for HIV-1 antibody reactivity, and (c) reporting results to CDC.

AIDS Serodiagnosis↗
PubMedDate not supplied

Reporting the results of human immunodeficiency virus testing.

We conducted a pilot study of potential sources of incorrect laboratory reports of human immunodeficiency virus type 1 testing using blind proficiency testing. Sets of three serum samples, including one serum sample with negative reactions in antibody tests, one serum sample with positive reactions, and one that gave false-positive results with certain testing kits, were sent as routine patient specimens to testing laboratories. Half the laboratories reported the serum sample positive for human immunodeficiency virus antibodies as "indeterminate"; one laboratory rendered a final positive report without supplemental testing. On the report forms, the actual laboratory results were often obscured and intermingled with information, sometimes incorrect, such as identifying the agent as "HTLV-III" (human T-cell lymphotropic virus type III) and advising that a test with positive results is evidence of exposure to the virus. Many of these reports have the potential to confuse, rather than to enlighten, the requesting physician.

AIDS Serodiagnosis↗
PubMedDate not supplied

Transcoronary and pulmonary vascular dynamics of endothelin-1 in heart transplant recipients.

BACKGROUND: Endothelin-1, a potent endothelium-derived vasoconstrictor peptide, has recently been shown to be elevated in heart transplant recipients and may be a participant in posttransplantation vasculopathy. METHODS: We measured peripheral venous endothelin-1 concentrations in eight heart transplant recipients and eight age- and gender-matched healthy controls. Subsequently, in 21 transplant recipients, right atrial, aortic, and coronary sinus plasma was obtained and endothelin-1 levels were measured. Potential correlations to donor and recipient age, cyclosporine levels, hemodynamic parameters, donor heart ischemic time, time from transplantation, and serum creatinine were examined. In eight more patients, right atrial levels of endothelin-1 were measured before and after endomyocardial biopsy to examine the effect of this procedure on endothelin-1 concentrations. RESULTS: Peripheral endothelin-1 concentrations were significantly higher in heart transplant recipients (45.6 +/- 1.8 versus 25.8 +/- 2.3, p < 0.001). Multiple regression analysis showed a significant correlation between right atrial endothelin-1 and pulmonary artery systolic pressure (r = 0.48), as well as serum creatinine (r = 0.52). No relation to blood pressure, right atrial pressure, pulmonary vascular resistance, recipient age, cyclosporine levels, or donor heart ischemic time was observed. In 11 patients, a 38% +/- 7% fall in endothelin-1 levels across the pulmonary bed was observed, suggesting extraction across the lung in these subjects. Nine patients had net release of endothelin-1 (95% +/- 26% rise) across the coronary vascular bed, whereas 12 patients showed net extraction (24% +/- 4% fall). Endomyocardial biopsy had no influence on endothelin-1 levels (prebiopsy: 48.3 +/- 1.7; postbiopsy: 42.3 +/- 2.34; p = Not significant). CONCLUSION: These findings suggest that endothelin-1 levels in transplant recipients may be influenced by renal function and may contribute to pulmonary hypertension. The significance of transcardiac release of endothelin in some patients is unclear: further studies are needed to determine the pathophysiologic significance of endothelin-1 in heart transplant recipients.

Adult↗