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Biomedical subjects

J W Scott

Publications and source records attributed to J W Scott.

132 records · Page 8Linked to original sources
PubMedDate not supplied

A method for differentiation and analysis of quinine and quinidine by gas chromatography/mass spectrometry.

A method is presented for the positive identification of quinine and quinidine. The method requires extraction of the compounds from an alkaline solution into an organic solvent and concentration of the sample by evaporation of the solvent. The sample is chromatographed without derivatization and may be detected by the flame ionization detector (FID) or mass spectrometry (MS). Limits of sensitivity are less than 5 ng per assay for the underivatized compounds. Analysis of urine extracts is discussed.

Chemical Phenomena↗
PubMedDate not supplied

Avirulence gene avrRxv from Xanthomonas campestris pv. vesicatoria specifies resistance on tomato line Hawaii 7998.

The molecular and genetic control of the interaction between tomato races of Xanthomonas campestris pv. vesicatoria (XcvT) and tomato was studied. Based on inoculation phenotype and analysis of in planta bacterial growth, tomato line Hawaii 7998 is resistant to XcvT race 1 75-3 but not to XcvT race 2 89-1. Two cosmid clones from a genomic library of XcvT race 1 75-3 converted the normally virulent race 2 89-1 to avirulence on Hawaii 7998. The two clones contained the previously isolated, nonhost avirulence gene avrRxv, and their activity was localized to a 2.1-kbp subclone of avrRxv. avrRxv inhibits growth of race 2 89-1 in the resistant line Hawaii 7998 and an insertional mutation in avrRxv prevents this inhibition. In addition, a dramatic increase in electrolyte leakage of leaves of Hawaii 7998 occurred after 12-hr postinfiltration with race 2 89-1 carrying avrRxv. The nucleotide sequence of avrRxv revealed one major open reading frame (ORF) that accords well with activity analysis of nested deletions. ORF 2-2 encodes a putative protein of 374 amino acids with a molecular weight of 42.1 kDa and a pI of 10.7. Inheritance of the avrRxv-specific resistance in Hawaii 7998 was studied in a total of 587 F2 individuals from crosses between Hawaii 7998 and susceptible lines. The inheritance of avrRxv-specific resistance in Hawaii 7998 appears to be governed by more than one locus.

Amino Acid Sequence↗
PubMedDate not supplied

Cyclosporine blood monitoring after heart transplantation: a prospective comparison of monoclonal and polyclonal radioimmunoassays.

Management of heart transplant patients who are being given cyclosporine is complicated by the variety of methods available for measuring cyclosporine levels and the current trend toward exclusive use of monoclonal assays. To facilitate clinical decisions regarding cyclosporine levels when converting from a polyclonal system to monoclonal system, 79 heart transplant patients underwent a prospective study to compare the polyclonal radioimmunoassay with the monoclonal-specific parent compound and nonspecific radioimmunoassays. Multivariable regression analyses were performed to generate best-fit equations for conversion of one assay to another. The closest correlation was noted in converting the measurement of cyclosporine parent compound with metabolites by the polyclonal method to the monoclonal method (nonspecific), R2 = 0.93. Considerable variability existed in the relationship between polyclonal and monoclonal-specific levels (R2 = 0.66) and between monoclonal-nonspecific and monoclonal-specific levels (R2 = 0.66), and both relationships were affected by hepatic function. Inferences: (1) The conversion of numeric cyclosporine levels from parent compound to parent plus metabolites is not completely predictable and must be empirically determined with the generation of appropriate regression equations. (2) Caution is advisable when a transplant team adopts a new cyclosporine assay for clinical use; formal study between existing assay methods and any newly adopted assay is warranted to prevent inadvertent underdosing or overdosing with cyclosporine.

Cyclosporine↗