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S Jovanovich

Publications and source records attributed to S Jovanovich.

8 recordsLinked to original sources
PubMed2000

HLA-B27 expression by flow cytometry: an analysis of 7 years quality assurance data.

The Royal College of Pathologists of Australasia Quality Assurance Programs Pty. Ltd. has been monitoring HLA-B27 assignment by flow cytometry for 7 years as part of the Immunology Program. Here we present data that demonstrates a gradual improvement in reports of false positive and negative results. Many participating laboratories demonstrate an ability to assign HLA-B27 status correctly by flow cytometric means. This ability appears to be independent of reagent and methodology. However a small number of laboratories produce consistently unacceptable results that suggest poor quality assurance practice.

Flow Cytometry↗
PubMed2000

Capillary electrophoresis on microchip.

Capillary electrophoresis and related techniques on microchips have made great strides in recent years. This review concentrates on progress in capillary zone electrophoresis, but also covers other capillary techniques such as isoelectric focusing, isotachophoresis, free flow electrophoresis, and micellar electrokinetic chromatography. The material and technologies used to prepare microchips, microchip designs, channel geometries, sample manipulation and derivatization, detection, and applications of capillary electrophoresis to microchips are discussed. The progress in separation of nucleic acids and proteins is particularly emphasized.

Animals↗
PubMed1993

Quality assurance of immunodiagnostic tests in Australia: II. Five year review.

A Royal College of Pathologists of Australasia (RCPA) sponsored quality assurance program in clinical immunopathology has, over a 5 year period, demonstrated: enrollment by the majority of immunodiagnostic laboratories in Australia and New Zealand; improved compliance with the program over time eg. increasing numbers returning their replies by the due date; different commercial techniques give different mean values for the same analyte. This appears to be due to the use of different reference materials in each technique; greater utilization of nephelometric techniques in quantitating immunoglobulins, C3, C4, CRP and rheumatoid factor resulting in better accuracy and precision; improvement in the frequency of detecting anticentromere antibody as most laboratories use proliferating cell lines as substrate for anti-nuclear antibody (ANA) detection; improved interlaboratory concordance of ANA titers by the provision of reference standards; improved detection of antibodies to extractable nuclear antigens (counter-immunoelectrophoresis being more sensitive than immunodiffusion); the Farr and radioimmunoassay technique for the demonstration of antibodies to native DNA have greater sensitivity than the Crithidia assay; improvement in accuracy and precision of cell phenotype analysis with the use of whole blood and cell flow cytometric techniques; development of techniques to rank each laboratories performance on a rating scale based on the average number of tests outliers (from the consensus mean) per mailing. However deficiencies in performance are still being observed. These relate to both technical factors causing systematic errors and in the provision of interpretive comments on the laboratory result. Continuing education and participation in quality assurance programs are emphasized to monitor and improve performance over time.

Australia↗
PubMed1991

Quality assurance of immunodiagnostic tests in Australasia.

A Royal College of Pathologists of Australasia (RCPA) sponsored Quality Assurance Program (QAP) in Clinical Immunology, involving 128 laboratories over a 1 yr period, revealed the following: successful participation in the program by 16 overseas laboratories (distant from Australia); only 30% of laboratories succeeded in returning their results by the scheduled date on every occasion; quantitation of urinary total protein and Bence Jones protein was poor and varied over a log scale; immunofixation was more successful in characterizing urinary paraprotein than immunoelectrophoresis; densitometry of protein electrophoresis appeared the method of choice in quantitating serum paraproteins accurately; nephelometric techniques gave better concordance between laboratories than turbidometric, radial immunodiffusion or agglutination techniques; poor concordance between laboratories in detecting weakly positive antinuclear antibodies (ANA); some laboratories had difficulties in identifying ANA patterns (only 60% of laboratories correctly identified the anticentromere pattern); few laboratories could correctly identify antibodies to extractable nuclear antigens (ENA); flow cytometry gave a smaller dispersion of lymphocyte subpopulation percentages than microscopy. A method was established to rank laboratory performance of selected tests over the 1 yr period. Such a comparative ranking scheme may alert laboratories in identifying specific or generalized deficiencies in performance.

Antibodies, Antinuclear↗
PubMed1980

Sites of synthesis of viral proteins in avian sarcoma virus-infected chicken cells.

We determined the sites of synthesis of avian sarcoma virus-specific proteins in infected chicken cells by immunoprecipitation of the products synthesized in vitro by free and membrane-bound polyribosomes; 85% of Pr76, the precursor of the viral internal structural proteins (group-specific antigens), was synthesized on free polyribosomes, and 15% was synthesized on membrane-bound polyribosomes. Pr92, the lycosylated precursor of the viral glycoproteins (gp85 and gp35), was synthesized exclusively on membrane-bound polyribomes, which is consistent with its role as a membrane protein. When we investigated the site of synthesis of pp60src, the product of the avian sarcoma virus src gene, we found that 90% was synthesized on free polyribosomes, whereas 10% was detected on membrane-bound polyribosomes. The implications of these results with respect to the subcellular location of pp60src are discussed.

Alpharetrovirus↗
PubMed1980

Leakage of nuclear transcripts late in simian virus 40-infected CV1 cells: quantitation of spliced and unspliced late 19S RNAs.

During the late phase of simian virus 40 infections of CV1 cells, the relative ratios of the spliced to the unspliced RNA molecules of the 19S family were measured. In the cytoplasm, unspliced 19S RNA represented between 1 and 2% of spliced 19S RNA. This ratio could be altered by the use of different methods of RNA extraction such that unspliced RNA was observed at 10 to 20% of spliced RNA. The nuclear ratios of spliced to unspliced 19S RNA were also determined. In contrast to cytoplasmic RNA, nuclear unspliced RNA was several hundred percent that of nuclear spliced 19S RNA. Cytoplasmic unspliced 19S RNA appears to be of nuclear origin, and its presence in the cytoplasmic fraction is due to nuclear leakage during RNA fractionation.

Animals↗
PubMed1976

Early gene expression in bacteriophage T7. I. In vivo synthesis, inactivation, and translational utilization of early mRNA's.

In vivo decay rates for the individual T7 early mRNA species were determined. The physical half-lives, measured at 37 C, range from 1.1 min for gene 0.7 RNA to 4.5 min for gene 0.3 RNA. Physical half-lives, as observed after rifampin inhibition of RNA synthesis and polyacylamide electrophoresis of RNAs, are approximately 30% longer than functional half-lives, as observed by 14C-labeled amino acid uptake into individual T7 early proteins. The different RNA species are synthesized at grossly different rates, 0.3 RNA at four times the rate of 1.0 RNA, 0.7 RNA at twice the rate, and 1.1 and 1.3 RNAs at about the same or a slightly lower rate than 1.0 RNA. Rho-factor-mediated termination of transcription behind genes 0.3, 0.7, and perhaps behind 1.0 is inferred from these data. The in vivo translational utilization of the individual T7 early-message species was found to vary by not more than a factor of 2.

Coliphages↗