Search PubMed⌕ Search

Biomedical subjects

R E Cross

Publications and source records attributed to R E Cross.

At least 37 records · Page 2Linked to original sources
PubMed1977

Enzyme-coupled measurement of uric acid in serum with a centrifugal analyzer.

An early-reading blank-corrected end-point determination of uric acid in serum has been developed for use with a centrifugal analyzer. The method is based on a modification of the uricase (urate:oxygen oxidoreductase, EC 1.7.3.3)/catalase (hydrogen peroxide:hydrogen peroxide oxidoreductase EC 1.11.1.6)/aldehyde dehydrogenase (aldehyde:NAD(P)+ oxidoreductase, EC 1.2.1.5)-coupled analytical scheme reported by Haeckel [Z. Klin. Chem. Klin. Biochem. 14, 101 (1976)]. Sensitivity and precision of the method are excellent, and results compare well with those obtained by the Kageyama procedure [Clin. Chim. Acta 31, 421 (1971)].

Aldehyde Oxidoreductases↗
PubMed1977

Adaptation to the centrifugal analyzer of an enzymatic method for the measurement of lactate in plasma and cerebrospinal fluid.

A fully enzymatic method for measurement of l(+)-lactate has been adapted for use with a centrifugal analyzer. The procedure is based on a two-point fixed-time kinetic approach for elimination of static interferences, and commercially available reagents are used. Specimen collection and preservation are simplified by the use of standard evacuated tubes containing sodium fluoride. Under these conditions lactate is stable for as long as seven days at 4 degrees C, and deproteinization is unnecessary. The method is extremely simple and ideally suited for emergency and routine use. Determinations may be performed on plasma or cerebrospinal fluid. Sensitivity and precision are excellent, linearity extends to 8.0 mmol/liter, and results compare well with those obtained using the manual enzymatic procedure.

Alanine Transaminase↗
PubMed1976

An integrated approach to lipid profiling: enzymatic determination of cholesterol and triglycerides with a centrifugal analyzer.

We describe enzymatic methods for determination of cholesterol and triglycerides (triacylglycerols), adapted for use with a centrifugal analyzer. Triglycerides are determined by a two-point kinetic method, which utilizes a single glycerol standard for calibration and provides for a within-run reagent blank correction. The endpoint determination of cholesterol combines the unique blanking capabilities of the centrifugal analyzer to correct for sample and reagent blank interferences. Results correlate well with those obtained by procedures standardized by the Lipid Research Clinics Program for use with a continuous-flow system.

Autoanalysis↗
PubMed1976

Improved method for measurement of inorganic phosphate in serum with a centrifugal analyzer.

A direct mehtod [Clin. Chim. Acta 46, 113 (1973)] for determination of inorganic phosphate in serum was adapted for use with a centrifugal analyzer. Contamination is minimized and analysis rate maximized by doing the reaction in the reagent wells of the transfer disc and by utilizing the high-speed spectrophotometric and data-reduction capabilities of the centrifugal analyzer. Hemolysis, icterus, and moderate lipemia cause no interference. Grossly lipemic sera and sera from patients with plasma cell dyscrasias can be analyzed by incorporating appropriate blanking and dilution techniques. The method exhibits excellent sensitivity and precision and results correlate well with those from a continuous-flow procedure.

Autoanalysis↗
PubMed1976

Adaptation of blank-corrected methods for measurement of total and conjugated bilirubin and uric acid to the centrifugal analyzer.

The blank-corrected determination in serum of total and conjugated bilirubin and of uric acid has been adapted to the centrifugal analyzer. Bilirubin is measured by a modified Jendrassik and Grof procedure; uric acid is determined kinetically by using a reaction based on reduction of ferric ion, including a uricase-treated blank. Sensitivity and precision of both methods are excellent, and results compare well with those obtained by commonly used procedures.

Autoanalysis↗
PubMed1975

Evaluation of kinetic light scattering as an approach to the measurement of specific proteins with the centrifugal analyzer. I. Methodology.

A laser-modified centrifugal analyzer was used to develop kinetic light scattering methods for the measurement of human immunoglobulins IgG, IgA, and IgM. Comparison of equilibrium light scattering methods with kinetic procedures for IgG and IgA demonstrate equivalent precision and relative accuracy. However, quantitative results obtained by equilibrium and kinetics methods for IgM were found to differ significantly. Recovery studies performed with purified IgM have shown that both methods can yield quantitative results in the normal range. Our observations demonstrate that the technique offers a viable and in some respects a superior alternative to other methods currently used in the clinical laboratory.

Autoanalysis↗
PubMedDate not supplied

Measurement of trazodone using solid-phase extraction and wide-bore capillary gas chromatography with nitrogen-selective detection.

A method for the determination of the antidepressant drug trazodone is presented. 8-Hydroxyloxapine is used as the internal standard. A simple solid-phase extraction procedure utilizing disposable reversed-phase C18 columns is described. Samples are analyzed by gas chromatography with nitrogen-selective detection using a wide-bore capillary column with a permanently bonded, nonpolar stationary phase. The assay possesses linearity to 3.0 micrograms/mL, sensitivity to at least 0.25 microgram/mL, recovery averaging 96%, and between-run precision reflected by a CV of 5.6%. We conclude that the method reported here is ideally suited for monitoring therapeutic and toxic levels of trazodone.

Chromatography, Gas↗