PubMed Health⌕ Search

Biomedical subjects

E J van Kampen

Publications and source records attributed to E J van Kampen.

At least 19 recordsLinked to original sources
PubMed1986

Simultaneous spectrophotometric calibration of wavelength and absorbance in an interlaboratory survey using holmium oxide (Ho2O3) in perchloric acid as reference, compared with p-nitrophenol and cobaltous sulphate solutions (1978-1984).

The wavelength accuracy of ten different types of spectrophotometer was tested with holmium perchlorate solutions. It was found to be good, with mean deviations from the literature values of maximally 0.3 nm. Standard deviations over the entire spectral range were within 0.75 nm. The absorbance accuracy for different types of instruments was generally within 5%, except in the 287 nm range where higher deviations were found. The sharpness of the holmium peaks, in combination with band width and sensitivity of the instruments, troubled the majority of the participants. 150 spectrophotometers were involved in the surveys. Linearity of the spectrophotometers was tested with p-nitrophenol and cobaltous sulphate and found to be satisfactory.

Chemical Phenomena↗
PubMed1986

Results of routine determination of clinically significant hemoglobin derivatives by multicomponent analysis.

Our recently developed multiwavelength method for multi-component analysis of hemoglobin (Hb) derivatives (Clin Chem 1984;30:373-379) was adapted for routine use in the clinical chemical laboratory. The method was applied in 4066 determinations on blood specimens from patients awaiting major surgery (n = 3863) or visiting the outpatient department for pulmonary disease (n = 203). Mean total hemoglobin concentration was 141 (SD 14) g/L. The proportion of HbCO was slightly to moderately increased (1.5-10.0%) in 36.5% of all patients; in a few cases it was as high as 15%. Mean methemoglobin was 0.4% (SD 0.2%) in the surgical patients, but 1.5% (SD 0.8%) in the patients with pulmonary disease. In some patients of the latter group the proportion of methemoglobin amounted to 5%. Sulfhemoglobin was found less than 0.4% in all specimens. Interference by paraproteins and by increased concentrations of bilirubin and lipids in plasma was easily detected by means of the performance checks provided by the spectrophotometer (an HP 8451 UV/Vis). The method is equally suitable for measuring blood samples containing fetal hemoglobin.

Adolescent↗
PubMed1984

Multicomponent analysis of hemoglobin derivatives with reversed-optics spectrophotometer.

We describe a method for the simultaneous determination of the five clinically relevant hemoglobin derivatives (Hb, HbO2, HbCO, Hi, SHb) in a blood sample by means of a reversed-optics spectrophotometer (Hewlett-Packard HP8450 A UV/Vis). A built-in computer program is used for multicomponent analysis in an overdetermined system, i.e., a system in which the number of independent equations used exceeds the number of unknowns to be determined. First, the spectra of the five hemoglobin derivatives are measured in a series of different human blood samples. Thereafter, the multicomponent method for the simultaneous determination of the five hemoglobin derivatives is tested by comparison with conventional methods for the separate determination of oxygen saturation, HbCO, Hi, and SHb fractions. The multicomponent (multiwavelength) method is sufficiently reliable, accurate, and easy to justify its use in physiological chemical research as well as its routine application in the clinical chemical laboratory.

Carboxyhemoglobin↗
PubMed1981

A multi-wavelength spectrophotometric method for the simultaneous determination of five haemoglobin derivatives.

A method is described by which the concentration of deoxyhaemoglobin, oxyhaemoglobin, carboxyhaemoglobin, haemoglobin and sulfhaemoglobin in a human blood sample is determined by passing the haemolysate without air contact through a coarse filter and subsequently measuring the absorbance at lambda = 500, 569, 577, 620 and 760 nm. The ensuing set of equations is solved by matrix calculation with the aid of a simple computer program. The method has been tested by comparing it with conventional methods for the determination of the various haemoglobin derivatives separately.

Carboxyhemoglobin↗
PubMed1981

Interlaboratory investigation on the CEA assay (Roche) with column filtration, dialysis and ultrafiltration techniques.

An interlaboratory study on the reproducibility of the CEA (Roche) RIA Test was carried out. Four different plasma pools of approximately 2, 3, 6, and 12 micrograms/l CEA were tested over a period of 4 weeks with 4 different lots of reagents in order to determine the interassay variances. At the same time we compared the lately introduced column technique with the dialysis and ultrafiltration method. Best results were obtained with the column technique which also showed best reproducibility. Only 1.4% of samples showed deviations greater than 5% between the mean of CEA duplicates and single CEA values, and these were omitted from the evaluation. On the other hand about 15% of the corresponding dialysis results showed deviations greater than 5% and were excluded from the evaluation. The methods compared showed a good correlation with a coefficient of 0.96, but the average values for the CEA determination, using the columns technique were lower than those obtained from dialysis. Interassay variances were greater for the dialysis procedures, i.e. 1.88 +/- 0.81, 3.25 +/- 0.83, 5.81 +/- 1.09, and 11-91 +/- 1.23 compared with 1.77 +/- 0.54, 2.63 +/- 0.68, 4.89 +/- 0.79, and 11.16 +/- 1.23 for the column technique. There were no systematic changes of the CEA values over the period of 4 weeks, thus giving optimal conditions for a follow up of patients.

Carcinoembryonic Antigen↗
PubMed1977

Ionic composition of arterial and mixed venous plasma in the unanesthetized dog.

The use of permanent catheters in the aorta and pulmonary artery permitted the establishment of normal values for hemoglobin concentration in blood and -or pH, PCO2, osmolality, and protein and electrolyte concentrations in the plasma of arterial and venous samples from unanesthetized, undisturbed dogs, and the comparison of the ionic composition of simultaneously taken arterial and venous samples. Arterial samples yielded the following mean values: CHb, 143 g liter-1; pHP, 7.427; PCO2, 32.5 mmHg; CPosmol, 295 mmol kg-1; CPpr, 73.1 g liter-1, CPNa+, 148.0; CPK+, 3.9; CPCa2+, 2.38; CPMg2+, 0.85; CPCl-, 116.0; CPHCO3-, 21.1; CPlact-, 1.4; CPphosph, 1.21; net cation equivalency, 16.4; and anion gap, 1.03 mmol liter-1 in eight male mongrel dogs with seven or eight samplings from each dog. The anion gap in arterial and venous plasma was small, indicating that the contribution of sulfate and organic acids to the ionic composition of dog plasma is quantitatively unimportant. In simultaneously taken arterial and venous samples the following significant arteriovenous differences were found: HP, +0.038; PCO2, -5.6 mmHg; CPosmol, -1.8 mmol kg-1; protein, -0.8 g liter-1; CPNa+, -1.0; CPK+, -0.1; CPCl-, +1.3; and CPHCO3-, -1.7 mmol liter-1. These differences are explained on the basis of the changes that occur in blood upon the addition of CO2 and the ensuing chloride and water shifts.

Animals↗
PubMed1975

Outflow from the left and the right coronary artery into the coronary sinus in the dog heart in situ.

The fractions of the left and the right coronary arterial flow determining coronary sinus flow (facs, facd) were measured in the open-chest dog. Both coronary arteries were isolated and perfused at the same pressure, while the sinus outflow was isolated and drained against the prevailing mean pressure in the right atrium. The fractions were determined by injecting 51Cr labeled erythrocytes into each coronary artery selectively and measuring the total resulting radioactivity in the sinus blood. In addition, they were estimated from flow measurements. The values of facs and facd were found to approximate 0.70 and 0.02 respectively. The variability between the different dog hearts was considerable and it was demonstrated that they were not intercomparable with respect to their coronary flow distribution.

Animals↗