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Biomedical subjects

J L Giegel

Publications and source records attributed to J L Giegel.

8 recordsLinked to original sources
PubMed1989

Two rapid and simple enzyme immunoassays for human antibodies to Entamoeba histolytica.

Two rapid and simple enzyme immunoassays (EIA) for antibodies to E. histolytica the protozoa causing ambiasis, are described. In the rapid dot EIA, a qualitative procedure, antigens were dried as a small dot (3 mm in diameter) on a thin white opaque polystyrene strip and serum samples were assayed undiluted. The assay required 3 incubation periods, 1 to 3 minutes each, and was completed in 9 minutes, with a positive reaction revealed as a blue color (precipitate) on the antigen dot and negative as colorless. The developed color is stable for permanent record. In the Microwell EIA, a quantitative procedure, antigens were dried in the Microwells. The assay also consisted 3 incubation periods of 15 minutes each, and was completed in 50 minutes. The results in absorbance values were normalized to EIA units (EU). Both tests had good reproducibility, sensitivity and specificity; and highly correlated with 3 other serologic tests. Their reagents can be stored for more than a year. Both tests could be suitable for small and physicians' office laboratories, especially in developing countries.

Animals↗
PubMed1982

Radial partition immunoassay.

In radial partition immunoassay, radial chromatography is used for performing an immunoassay. We describe the application of this technology to the measurement of digoxin in serum by enzyme immunoassay, with the entire testing procedure carried out on glass-fiber filter paper. A sample is applied to a small central area of the filter paper, where it reacts with the antibody to digoxin immobilized there. Subsequently, enzyme-labeled digoxin is applied to react with remaining antibody sites. After incubation, substrate for the enzyme is applied to the center of the reaction area and washes out any unbound label to the periphery of the paper. This step also initiates the enzyme reaction, which is quantified by front-surface fluorescence. A microprocessor-controlled automated instrument has been developed to process the filter paper matrix through the above sequence, and calculate the final result. Total testing time for digoxin is less than 7 min.

Antibodies↗
PubMed1979

Further observations on the incidence and nature of atypical creatine kinase activity.

The interference of atypical creatine kinase (CK; EC 2.7.3.2) with anion-exchange methods for the measurement of the CK-MB isoenzyme is now firmly established. False-positive results from this source are much more common than interferences caused by the BB isoenzyme. Atypical CK, at least in some patients, does not appear to be a genetic variant, nor could we relate it to a specific clinical diagnosis, to hypoxia, or to administration of a particular drug. Its behavior in an immuno-inhibition test for CK-B subunit indicates an immunological difference from the normal M subunit. Thus the change in immunological properties is associated with the altered electrophoretic properties. The variability of electrophoretic patterns suggests that atypical CK may represent multiple forms of creatine kinase rather than a unique entity.

Aged↗
PubMed1976

Atypical increase in serum creatine kinase activity in hospital patients.

We use an ion-exchange column-chromatographic technique for separating creatine kinase isoenzymes in serum, and occasionally observe what appears to be sustained increase in the MB fraction. Most patients whose sera show such behavior have myocardial disease, but not necessarily a recent myocardial infarction. Electrophoretic analysis of a small sampling of such sera revealed that the apparent MB migrates atypically, appearing distinctly between isoezymes MB and MM. In another electrophoretic system, the peak might easily be mistaken for MM. This unusual isoenzyme does not appear to be "macro" creatine kinase. In laboratories that use the ion-exchange technique, the possibility of a falsely positive MB value should be considered in subjects who show persistent increases together with normal or nearly normal values for total creatine kinase activity. A suitable electrophoretic method that clearly demonstrates this unusual isoenzyme should be used in such cases, for confirmation.

Aged↗
PubMed1975

Manual and semi-automated procedures for measurements of triglycerides in serum.

We describe manual and semi-automated procedures for serum triglyceride determinations, in which lipids are partitioned between a water/isopropanol phase and a nonane phase. More than 99% of the triglyceride is extracted into the nonane phase, as determined by recovery of 3H-labeled triolein. Studies with 14C-labeled lecithin demonstrate that less than 1.3% is extracted into the nonane phase at concentrations up to 2.5 g/liter. A novel feature of the method is that glycerol can be liberated from triglyceride by sodium hydroxide at room temperature in less than 5 min. Glycerol is oxidized by periodate in 1-2 min at 25 degrees C; the formaldehyde produced is reacted with 2,4-pentanedione to yield 3,5-diacetyl-1,3-dihydrolutidine. The manual procedure requires less than 20 min; the semi-automated method requires 7 min from sampling to readout. The procedure may be run at 30-40 samples/h, with stable baseline and less than 2.0% carryover. Both methods are linear to 0.50 g (5.6 mol) of triolein per liter. Analytical recoveries at several concentrations ranged from 97-101% (mean, 100%).

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