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Biomedical subjects

S R Abbott

Publications and source records attributed to S R Abbott.

13 recordsLinked to original sources
PubMed1987

Development and utility of a monoclonal-antibody-based, highly sensitive immunoradiometric assay of thyrotropin.

Using improved selection techniques, we isolated four monoclonal antibodies with high affinity for human thyrotropin (Ka = 1.6 X 10(8) to 2.6 X 10(10) L/mol). We used two of these in an immunoradiometric assay (IRMA) that also incorporates a novel phase-separation technology (Sucrosep TSH IRMA, Boots-Celltech). This assay's very low detection limit for TSH (0.03-0.08 milli-int. unit/L) and wide working range (0-250 milli-int. unit/L) allow the differential diagnosis of hypothyroid, euthyroid, and hyperthyroid patients. We compare the utility of this IRMA with that of a RIA for patients with various thyroid disorders. As determined by IRMA, a normal concentration of TSH in serum excludes hyperthyroidism or hypothyroidism, whereas an undetectable serum TSH concentration (less than 0.08 milli-int. unit/L) accurately predicts an abnormality in thyroid gland function.

Antibodies, Monoclonal↗
PubMed1985

Measurement of interferon from in vitro stimulated lymphocytes by bioassay and monoclonal antibody-based immunoassay.

Peripheral blood mononuclear cells (PBMC) derived from healthy individuals were stimulated with u.v.-inactivated Newcastle disease virus and the cell supernatants were assayed for both antiviral activity and alpha interferon (IFN-alpha) immunoreactivity. IFN-alpha concentrations determined by two immunoradiometric assays (IRMAs) based on monoclonal antibodies that recognize different IFN-alpha subtypes correlated well together (r = 0.96) and with interferon concentrations determined by the two bioassays (r = 0.82 to 0.89), but the agreement between the results of the two bioassays was not as close (r = 0.79). As judged by the agreement between determinations on duplicate inductions of the same PBMC, the IRMAs were considerably more precise than the bioassays. Despite the use of a common IFN standard there were marked differences in the absolute titres of IFN determined by the IRMAs and bioassays, highlighting the difficulties in standardizing assays for IFN-alpha. The IRMA results suggest that there are no major differences in the spectrum of IFN-alpha subtypes produced by healthy individuals under conditions of viral stimulation.

Animals↗
PubMed1980

Practical aspects of normal-phase chromatography.

Normal-phase chromatography in HPLC typically encompasses adsorption chromatography on silica and partition chromatography on cyano and amino bonded phases. Unique separations are provided for saccharides, isomers, steroids, and class separations of lipids and polynuclear aromatic hydrocarbons.

Chromatography, High Pressure Liquid↗
PubMed1980

Serum protein profiles by "high-performance" liquid chromatography with detection at multiple wavelengths.

We have separated serum proteins in only 15 min by high-performance liquid chromatography. The identification of several peaks in the chromatographic profile was greatly aided by the use of multiple-wavelength detection. We have found a good correlation between retention times and electrophoretic mobilities. Serum samples with increased gamma- or beta-globulins, as determined by electrophoresis, resulted in chromatographic profiles with strongly increased peaks in the appropriate regions. This chromatographic method revealed both relative and absolute differences in individual protein concentrations among several serum samples.

Blood Proteins↗
PubMed1979

High-speed steric exclusion chromatography of biopolymers.

Biopolymer separations were studied on Micropak TSK type SW columns, which contain an aqueous compatible steric exclusion support. Columns of two different pore sizes, designated 2000SW and 3000SW, were compared for separation of proteins and nucleic acids covering a molecular weight range of 13,500 to 340,000 and the effect of molecular shape and denaturation upon elution volume was investigated. Use of high-speed steric exclusion chromatography as a prefractionation step prior to ion-exchange chromatography in biopolymer purification schemes is discussed.

Animals↗
PubMed1979

Ion-exchange separation of nucleic acid constituents by high-performance liquid chromatography.

The high-performance liquid chromatographic separation of a large variety of nucleic acid constituents on a silica-based, weak-anion exchange column was accomplished. Using this technique it was possible to achieve some relatively difficult separations, such as the separation of 2'-, 3'-, and 5'-AMP, and the separation of a mixture of ribo- and deoxyribo-nucleosides and -nucleotides. A number of other separations are demonstrated by isocratic or gradient elution. These include the separation of a mixture of nucleoside monophosphates, the separation of a mixture of nucleoside mono-, di-, and triphosphates, the separation of a mixture of nucleosides and bases, and the separation of a mixture of nucleotide oligomers. These chromatographic separations were accomplished using relatively simple experimental procedures at ambient temperatures and involved relatively short analysis times. Excellent separations were obtained, in most cases, by adjustment of buffer concentration and pH, or by addition of an organic modifier. In some cases, it was necessary to use gradient elution to achieve optimum resolution.

Animals↗
PubMed1979

Plasma cyclic-AMP response to parathyroid hormone in Turner's syndrome and Albright's hereditary osteodystrophy.

Purified bovine parathyroid hormone (BPTH) given by injection to five patients with Turner's syndrome, and seven healthy volunteers produced a significant rise in plasma cyclic AMP reacing a maximum within 10 min. In a pseudohypoparathyroid patient there was no increase. Urinary excretion of cyclic AMP exceeded the normal in three out of four patients with Turner's syndrome. Thus, if there is a relationship between Turner's syndrome and Albright's osteodystrophy it is with the incomplete form known as pseudo-pseudohypoparathyroidism.

Adult↗
PubMed1975

High pressure liquid chromatography of cannabinoids as their fluorescent dansyl derivatives.

Four different cannabinoids were converted to their 1-dimethyl-aminonaphthalene-5-sulfonate (dansyl) derivatives. Standards mixtures were separated by high pressure liquid chromatography and detected with an experimental filter fluorometer with sub-nanogram sensitivity. The effect of solvent properties on fluorescence spectra and quantum yields was also studied.

Cannabis↗