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Biomedical subjects

W D Bostick

Publications and source records attributed to W D Bostick.

10 recordsLinked to original sources
PubMed1982

Biological markers as an aid in the clinical management of patients with liver metastases.

Liver metastases due to the more common neoplastic diseases such as colorectal, breast, or bronchogenic carcinoma are a frequent occurrence and are associated with an ominous prognosis. Earlier detection followed by appropriate therapeutic interventions might have a decided effect on the subsequent course of disease. Controversy exists over the selection of tests with the greatest sensitivity, specificity, and potential utility. Preliminary evidence suggest that gamma-glutamyl transpeptidase and 5'-nucleotidase may be of particular significance. Four enzymes--gamma-glutamyl transpeptidase, 5'-nucleotidase, leucine aminopeptidase, and alkaline phosphatase plus carcinoembryonic antigen--were compared in the same blood samples from selected patients with breast and small cell carcinoma of the lung. Gamma-Glutamyl transpeptidase was the most sensitive test with 28/29 (97%) patients with hepatic metastases having elevated enzymatic activity in their sera. For patients with small cell carcinoma of the lung followed serially, gamma-glutamyl transpeptidase activity was increased an average of 5 months before liver metastases were detected by clinical means. Two factors are important in the interpretation of the results of gamma-glutamyl transpeptidase analysis: (1) Hepatic dysfunction due to diseases other than metastatic tumor involvement can cause a rise in enzyme levels as can (2) medications or ethanol which activate the hepatic microsomal drug metabolizing system. Of particular importance, however, is the fact that antitumor chemotherapy, even intensive and multiple agent, did not appear to effect the enzyme activity in the sera of patients with breast or small cell carcinoma of the lung. Gamma-glutamyl transpeptidase in combination with carcinoembryonic antigen may be of particular value in detecting liver metastases and in assessing subsequent response to therapy.

Alkaline Phosphatase↗
PubMed1978

Separation and analysis of arylsulfatase isoenzymes in body fluids of man.

Soluble arylsulfatase (EC 3.1.6.1) is present in the body fluids of man in the form of two isoenzymes, arylsulfatase A and B, which reportedly are useful biochemical markers for certain types of malignancy. However, rapid assay of the individual isoenzymes is extremely difficult; procedures based on differential inhibition or activation of the isoenzymes in a mixture yield only semiquantitative results. A feature of these isoenzymes is their inhibition by some common anions (notably phosphate) at physiologic concentrations. The isoenzymes can be separated by anion-exchange chromatography, the B isoenzyme being eluted in the void volume and the A isoenzyme and the anionic inhibitors retarded. Lead is used to sequester phosphate, enabling measurement of A in the salt-eluted fraction. Using this technique, we have found significant elevations of B in the sera of patients with colorectal cancer. The potential of rapid, chromatographic separation coupled with continuous monitoring for arylsulfatase activity is discussed.

Cerebroside-Sulfatase↗
PubMed1978

Chromatographic separation and continuously referenced, on-line monitoring of creatine kinase isoenzymes by use of an immobilized-enzyme microreactor.

We describe a new concept in continuously referenced monitoring of the isoenzyme activities of creatine kinase (EC 2.7.3.2) after liquid-chromatographic separation. After separation on a diethylaminoethyl-Sephacel column, the three isoenzymes of creatine kinase undergo a series of coupled enzyme reactions, ultimately resulting in the formation of ultraviolet-detectable NADPH. A major advantage of this detection system is the immobilized-enzyme microreactor (2 X 17 mm), which may be removed and stored refrigerated when not in use. A split-stream configuation allows self-blanking of endogenous ultraviolet-absorbing constituents in authentic sera samples, which would otherwise make definitive diagnosis and quantitation difficult or impossible. This system is applicable to the automated analysis of creatine kinase isoenzymes in the clinical laboratory.

Chromatography, High Pressure Liquid↗
PubMed1977

Evaluation with the centrifugal fast analyzer of a chemical activation procedure for creatine kinase MB isoenzyme.

The differential activation method for the determination of the "myocardial" isoenzyme of creatine kinase (MB) is based on the computed difference in activity of serum aliquots activated by the combination of dithiothreitol and glutathione (skeletal plus myocardial creatine kinase) and by glutathione alone (skeletal creatine kinase). The unique ability of the Centrifugal Fast Analyzer to perform analyses in parallel is used to precisely measure (CV = 0.1-1.5%) the activity of the two chemically activated aliquots. Statistical considerations concerning the reliability of this difference estimation are discussed with respect to both the precision of the rate measurements and to the relative amount of isoenzyme MB present. Another potential source of error in the analysis of the two differently activated aliquots, namely variation in lag phases, is circumvented by use of a linear-search FOCAL software package. This program searches the data for a linear segment of maximum slope, automatically rejecting those data that appear in lag or depletion regions of the curve representing the progress of the reaction. Correspondence of the results obtained with those of comparison techniques (chromatography and electrophoresis) are discussed.

Centrifugation↗
PubMed1975

Development of a multipurpose optical system for use with a centrifugal fast analyzer.

A Centrifugal Fast Analyzer is basically a sophisticated photometric measuring device containing a multicuvet rotor as its major component. Several reactions are simultaneously initiated in the rotor, which is then rotated through a stationary optical monitor and the resulting signals acquired and processed by an on-line data system. ?With the miniature version of this analyzer, one has the option of directing the incident optical beam, via a fiber optical bundle, into the cuvets of the spinning rotor in either a 90 degrees or a 180 degrees orientation relative to the analyzer's photodetector. tthe combination of newly designed rotors and a flexible optical system having multiple configurations has provided a versatile system in which one can measure the transmittance, fluorescence, chemiluminescence, or light-scattering (either turbidimetrically or nephelometrically) properties of the ensuing reaction species, all with a single analyzer. This flexibility in choosing the optical mode in which a particular set of reactions is to be monitored provides the analyst with a powerful and versatile analytical tool for developing new methods for use in various clinical laboratory applications, including chemistry, toxicology, immunology, and hematology.

Autoanalysis↗
PubMed1975

Coagulation-time determination with automatic multivariable analysis, by use of a miniature centrifugal fast analyzer.

Use of a miniature Centrifugal Fast Analyzer for the parallel photometric monitoring of the coagulation process is shown to have a number of advantages. These include a choice of optical modes, virtually simultaneous initiation and observation of the coagulation process for a number of patient-plasma samples and an on-board control sample, small sample and reagent volume requirements, and automatic determination of a number of diagnostically useful variables (including relative fibrinogen content) from the data recorded in a single run. Also, the system is shown to give results that correlate well with those obtained by conventional techniques for determination of prothrombin time.

Autoanalysis↗