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Biomedical subjects

B W Renoe

Publications and source records attributed to B W Renoe.

14 recordsLinked to original sources
PubMed1988

Critical evaluation of the TDx Turbo Nephelometry System.

We critically evaluated the Nephelometry System (TDx Turbo) for the TDx Analyzer (Turbo), as currently used for immunoglobulins (IgA, IgG, and IgM) and transferrin assays. We describe hardware, software, reagent, and procedural changes made since the original publication (Clin Chem 1985;31:1474) and the mathematical treatment of data. The unit-dose format of the reagents allows for batch or panel testing of the analytes, with a throughput of 40 tests per hour. Measurements are made at pseudo-equilibrium, with sample-blank correction. The formulation of reagents and the assay scheme are such as to eliminate the need to check these assays for antigen excess. Assay sensitivities are 3% of the standard curve ranges. CVs are 8% for all assays. The system performance, when compared with rate nephelometry and radial immunodiffusion, yielded correlation coefficients of 0.97 or better for the analytes.

Humans↗
PubMed1983

Improved determination of aluminum in serum by electrothermal atomic absorption spectrophotometry.

This method for determining aluminum in human serum involves electrothermal atomic absorption spectrophotometry. A longer drying time allows less pre-dilution of the sample, and the method also includes a flush cycle after atomization. Standard-addition methodology is used to eliminate matrix effects and the need for a standard curve. We used this method on serum from 50 normal persons and from 34 patients with chronic renal failure who were on long-term intermittent hemodialysis. The mean normal serum aluminum concentration was 6.1 micrograms/L (CV 2.7%), and values for the patients ranged from 13 to 475 micrograms/L.

Aluminum↗
PubMed1981

Use of a flow-injection sample manipulator as an interface between a "high-performance" liquid chromatograph and an atomic absorption spectrophotometer.

We describe an integrated, molecular-absorbance, atomic absorption instrument for studying metal/ligand binding in clinical samples. For an interface between the "high-performance" liquid chromatograph and the atomic absorption instrument we used a flow-injection sample manipulator, thus allowing both the chromatograph and the atomic absorption detector to operate at their separate optimum conditions. After specimen separation with a gel permeation column, we measured the molecular components of the column eluate by molecular absorbance spectrometry and the atomic components (calcium and magnesium) by flame atomic absorption spectrophotometry. This instrument system is capable of separating and analyzing multiple components within 20 min of injection of the sample on the column. The chromatograms presented demonstrate the utility of the system for investigating metal binding to a variety of ligands in clinical samples.

Calcium↗
PubMed1980

The effects of stasis with and without exercise on free calcium, various cations, and related parameters.

The changes in free calcium, total calcium, albumin, protein, pH, lactate, sodium, magnesium, and potassium values during and following venous stasis (3 min at an external pressure of 100 mmHg) with and without forearm exercise have been measured. The pattern of changes observed with time were dependent on the presence or absence of forearm exercise. Without exercise significant changes are only observed at 1 min following stasis and then the increases are only moderate (free calcium 2.0%, total calcium 2.4%, albumin 6.9%, and protein 5.9%). However, when the forearm is exercised, larger increases (free calcium 8.6%, total calcium 8.4%, albumin and protein 12.4%) were observed for all parameters following stasis. These increases took 1 to 3 min to return to baseline for most parameters. Only potassium and magnesium went below baseline during the recovery period. It is recommended that when a tourniquet is used to aid in obtaining venous blood samples for these analytes, exercise of the forearm be avoided. If forearm exercise is unavoidable, then the sample should be obtained 1 to 3 min after release of the tourniquet.

Blood Circulation↗
PubMed1980

Automated multiple flow-injection analysis in clinical chemistry: determination of albumin with bromcresol green.

We describe an adaptation of automated multiple flow-injection analysis instrumentation to an analysis for albumin in serum. The bromcresol green reaction was used to test the utility of the system. The approach yielded albumin results with excellent sensitivity, no measurable carryover, a relative standard deviation of less than 1%, good correlations with published procedures, and no measurable interferences. The simplicity and flexibility of the instrumentation and its performance integrity, as indicated by the analytical results, make this a viable clinical chemical tool.

Bromcresol Green↗
PubMed1980

Automated multiple flow-injection analysis in clinical chemistry: determination of total protein with Biuret reagent.

We have examined the feasibility of the automated multiple flow-injection technique for application to clinical chemistry by adapting to this system the biuret method for the determination of total protein. Samples were discretely and rapidly introduced into a continuously flowing, nonsegmented reagent stream by means of an automatic sampler and high-pressure injection valve. Pumps operating at 1380-2070 kPa (200-300 psi) were utilized to introduce the biuret reagent and saline diluent into the system separately at flow rates of 72 and 47 microL/s, respectively. Use of 20-microL sample and a 3.0-s reaction-delay coil was adequately sensitive for analysis for total protein by this method. Samples were analyzed at a rate of 150/h with no detectable between-sample carryover. Within-run precision studies yielded relative standard deviations of 2.5% and less. Total protein values obtained by this method correlated well with those obtained by centrifugal analyzer and bubble-segmented continuous-flow biuret methods.

Autoanalysis↗
PubMed1979

Influence of posture on free calcium and related variables.

We measured free calcium and related variables before and after the subject changed from the upright to the supine posture, doing 15 separate such experiments on 11 healthy men. After such a change, free calcium (1.7 +/- 0.4%), total calcium (4.6 +/- 0.7%), total protein (11.5 +/- 1.4%), albumin (12.2 +/- 2.0%), total magnesium (3.8 +/- 0.9%), and the activity of hydrogen ion (2.9 +/- 1.0%) decreased significantly (values are means +/- SEM), but promptly reverted when three subjects assumed the alternative posture. Changes in lactate values were not rapidly reversible; sodium and potassium showed no significant change. The mechanism of the changes in free calcium is unclear, but they correlated only with the changes in total calcium and were notably less than the changes in total calcium, indicating that posture will have less effect on the interpretation of free calcium values than on values for total calcium.

Blood↗
PubMedDate not supplied

Enzymatic assay for creatinine with fixed-time kinetics on a centrifugal analyzer.

A method is described for enzymatic measurement of serum creatinine using a centrifugal analyzer. The method employs fixed-time kinetics and a true serum blank. The method required 100 microliters of serum and is linear to 90 mg per L. Day-to-day precision studies revealed a standard deviation (coefficient of variation) of less than +/- 0.5 mg per L (7.4 percent) at a mean creatinine concentration of 6 mg per L and +/- 0.5 mg per L (1.8 percent) at a mean value of 28 mg per L. The method was free of interferences from acetoacetic acid, ascorbic acid, bilirubin, and hemoglobin. The speed, precision, and accuracy of the method suggest that it represents a useful alternative to methods using the alkaline picrate procedure.

Amidohydrolases↗