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Biomedical subjects

A Buursma

Publications and source records attributed to A Buursma.

At least 19 recordsLinked to original sources
PubMed1998

Lyophilized bovine hemoglobin as a possible reference material for the determination of hemoglobin derivatives in human blood.

We investigated the suitability of a lyophilized bovine hemoglobin (LBH) preparation containing various fractions of oxyhemoglobin (O2Hb), carboxyhemoglobin (COHb), and methemoglobin (MetHb) for quality assessment in multicomponent analysis (MCA) of hemoglobin derivatives. It was demonstrated that a stable preparation of these components after reconstitution yields a hemoglobin solution that is spectrophotometrically equivalent with a fresh bovine hemoglobin solution. The preparation was found to be stable for at least 1 year when it is kept at 2-8 degrees C and for 1 h after reconstitution. We determined the fractions of O2Hb, COHb, and MetHb of several LBH preparations, using the complete spectra of 480-650 nm with 2-nm intervals and absorptivities as determined for pure LBH solutions. A field trial involving various types of multiwavelength hemoglobin photometers showed the suitability of LBH as a quality-control material. Computer models of the various common multiwavelength hemoglobin photometers may be useful for establishing more accurate target values of LBH preparations for each type of photometer and for studying the importance of the influence of specific factors such as wavelength selection, absorptivity values, and interfering dyes.

Animals↗
PubMed1993

Rapid multicomponent analysis of hemoglobin derivatives for controlled antidotal use of methemoglobin-forming agents in cyanide poisoning.

When cyanide poisoning is treated with a methemoglobin-forming agent, oxidative metabolism is protected at the expense of the oxygen capacity of the blood. The affinity of methemoglobin for CN- is high enough to compete with cytochrome oxidase, which protects the latter from becoming blocked, but all hemoglobin used for this purpose is lost for the transport of oxygen. Therefore, the fractions of the various hemoglobin derivatives present in the blood should be carefully monitored during this kind of treatment. After we had developed a multiwavelength spectrophotometric method for this purpose, we studied the feasibility of using a modified commercial six-wavelength hemoglobin photometer (Radiometer OSM3) for easy and rapid analysis of methemoglobin and methemoglobin cyanide in small samples of blood. All conditions appeared to be fulfilled for the construction of a practical multiwavelength photometer for reliably monitoring methemoglobin therapy in patients with cyanide poisoning, even in the presence of carboxyhemoglobin, as often occurs in fire victims.

Adult↗
PubMed1991

Absorption spectra of human fetal and adult oxyhemoglobin, de-oxyhemoglobin, carboxyhemoglobin, and methemoglobin.

We determined the millimolar absorptivities of the four clinically relevant derivatives of fetal and adult human hemoglobin in the visible and near-infrared spectral range (450-1000 nm). As expected, spectral absorption curves of similar shape were found, but the small differences between fetal and adult hemoglobin absorptivity were important enough that they should be taken into account in multicomponent analysis of hemoglobin derivatives. Common pulse oximeters, however, involving light of 660 and 940 nm, are so insensitive to the presence of fetal hemoglobin that they can be used safely in neonates. The error in pulse oximetry caused by the presence of carboxyhemoglobin is insubstantial, but methemoglobin gives either an understimation or an overestimation at high or low oxygen saturation, respectively, the turning point being near 70% saturation.

Adult↗
PubMed1988

Performance of an automated six-wavelength photometer (Radiometer OSM3) for routine measurement of hemoglobin derivatives.

A new instrument for spectrophotometric determination of oxygen saturation (SO2) and the fractions of carboxyhemoglobin (FHbCO) and methemoglobin (FHi), the Hemoximeter OSM3 (Radiometer), was tested by comparative measurements with a multiwavelength method. We found that it gave reliable results for freshly drawn samples from patients. When samples with artificially induced high proportions of HbCO or Hi, or both, were introduced, results were still sufficiently accurate. The presence of sulfhemoglobin (SHb) seriously interfered with the measurement of SO2, FHbCO, and FHi, but the instrument reliably indicated its presence. Because SHb is rarely encountered, a reliable warning for its presence is adequate for clinical practice. Using the instrument in its fetal mode, we obtained accurate results for blood samples from newborns.

Adult↗
PubMed1987

Spectrophotometry of hemoglobin: a comparison of dog and man.

1. The absorptivity at 540 nm of hemiglobincyanide (epsilon 540HiCN) from dog blood was determined on the basis of iron and found to be within the range formerly obtained for human hemoglobin. 2. Consequently, epsilon 540HiCN = 11.0, the established value for human hemoglobin, may be used for dog hemoglobin. 3. On this basis the absorption spectra of oxyhemoglobin, de-oxygenated hemoglobin, carboxyhemoglobin, hemiglobin (methemoglobin) and hemiglobincyanide were determined for dog hemoglobin. 4. No significant differences were found between dog and human hemoglobin, except that dog hemiglobin binds less OH- as reflected in a difference between the absorption spectra of dog and human hemiglobin at the same pH.

Animals↗
PubMed1987

A new trend in blood gas chemistry: the measurement of clinically relevant hemoglobin derivatives. Performance of the OSM3 hemoximeter.

Supplementing the determination of total hemoglobin (CHb*) and oxygen saturation (SO2) with measuring the fractions (F) of inactive hemoglobins (dyshemoglobins: carboxyhemoglobin, HbCO; methemoglobin, Hi; sulfhemoglobin, SHb) in human blood is becoming common practice in many hospitals. We tested the performance of a new instrument for this purpose, the hemoximeter OSM3 (Radiometer, Copenhagen, Denmark) by comparing the results with those of an established multiwavelength method (MWM). For 100 fresh blood samples from patients with SO2 ranging between 20 and 100%, the difference between the two methods (OSM3-MWM) was 0.90% SO2 +/- 1.14% (SD). A series of 214 consecutive blood samples from patients with FHbCO ranging from 0 to 12% showed for HbCO a difference (OSM3-MWM) of 0.03% FHbCO +/- 0.47% (SD). In the same blood samples FHi was between 0 and 1.4%. The OSM3 gave a mean value of 0.81%, the MWM 0.47%. In order to put the OSM3 to a more severe test we made from normal human blood several series of specimens with high concentrations of dyshemoglobins. The difference between OSM3 and MWM was for 37 specimens of blood with 1-60% HbCO 0.29% FHbCO +/- 0.96% (SD), and for 34 specimens of blood with 0-70% Hi -0.29% FHi +/- 2.29%. For specimens with high fractions of HbCO and Hi the agreement between the SO2 measurement made with the two methods remained good, even when the dyshemoglobins were present in combination. Hi fractions of up to 70% did not interfere with the measurement of HbCO; the same holds good for the measurement of Hi in the presence of HbCO.

Blood Gas Analysis↗
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↗
PubMed1983

Molar absorptivities of human hemoglobin in the visible spectral range.

In a recent paper, Burkhard and Barnikol (J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 52: 124-130, 1982) claimed that the absorption spectra of human (oxy-)hemoglobin are dependent on the total hemoglobin concentration (CHb) and it is suggested that this might also be the case with cyanmethemoglobin (HiCN). Such relationships would invalidate the widely used spectrophotometric methods for the determination of total hemoglobin and the fractions of various hemoglobin derivatives in human blood. Although Burkhard and Barnikol's findings are rather improbable considering earlier data, we measured the millimolar absorptivities of oxyhemoglobin (epsilon HbO2) and cyanmethemoglobin (epsilon HiCN) at various wavelengths over a wide range of concentrations (CHb approximately equal to 0.004-10 mmol x 1(-1)), using two different types of spectrophotometers. epsilon HbO2 and epsilon HiCN proved to be independent of CHb. Moreover the values obtained confirmed those in the earlier literature, whereas those of Burkhard and Barnikol are some 30% higher. Consequently there is no reason to doubt the validity of the generally accepted millimolar absorptivities of human hemoglobin.

Absorption↗
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

Determination of hemoglobin derivatives with IL 282 CO-oximeter as compared with a manual spectrophotometric five-wavelength method.

Hemoglobin derivatives as determined with the IL 282 CO-Oximeter correlated well with results by a manual five-wavelength method, which in turn had been checked against established methods for one or two derivatives. Measurement of total hemoglobin yielded almost identical results with both methods. As for oxyhemoglobin, carboxyhemoglobin, and hemiglobin, agreement between the two methods was fair. Although the IL 282 CO-Oximeter has not been constructed for the determination of sulfhemoglobin, it appeared that the instrument can still give a strong indication as to the presence of this hemoglobin derivative. Results from the IL 282 for fetal human blood should be used with caution, especially because of the possibility of falsely high HbCO readings.

Autoanalysis↗
PubMed1979

Spectrophotometric determination of oxygen saturation of blood independent of the presence of indocyanine green.

The strong absorbance of indocyanine green in a broad band around lambda = 800 nm invalidates the usual spectrophotometric two-wavelength methods for measuring oxygen saturation operating in the red and near infrared region. By proper wavelength selection, however, the effect of the dye can be eliminated. With the two-wavelength method utilising lambda = 660 and 860 nm oxygen saturation is measured virtually independent of the presence of indocyanine green.

Animals↗
PubMed1977

Carboxyhaemoglobin. Spectrophotometric determination tested and calibrated using a new reference method for measuring carbon monoxide in blood.

The spectrophotometric determination of HbCO at lambda = 562 and 540 nm in the system HbCO/HbO2 was reinvestigated using a new reference method for measuring CO in blood. This reference method is based on the conversion of CO from HbCO into CO2 which is determined by titration. Plotting the absorbance ratio A562/A540 against the titrimetrically determined HbCO fractions of 46 blood samples demonstrated a linear relationship up to 90% HbCO and yielded more accurate values for the constants in the equation for calculating the HbCO fraction from A562/A540. The standard deviation of the differences between the spectrophotometric and the titrimetric method was 1.2% HbCO. It is shown that the influence of other haemoglobin derivatives and other possible sources of error is either negligible or can be prevented by simple precautions.

Carbon Monoxide↗
PubMed1977

Sulfhaemoglobin. Absorption spectrum, millimolar extinction coefficient at lambda = 620 nm, and interference with the determination of haemoglobin and of haemiglobincy anide.

The spectrophotometry properties of sulfhaemoglobin (SHb) and some derivatives were investigated using an improved technique for measuring the SHb fraction induced in human blood samples. The millimolar extinction coefficient of SHb at lambda = 620 nm was found to be 20.8 (S.D. 1.48; S.E. = 0.44; n = 11). In addition it was demonstrated that the spectral changes occurring in SHb containing haemoglobin solutions upon the addition of KCN, K3Fe(CN)6 and K3Fe(CN)6 +KCN invalidate the KCN addition method for the determination of haemiglobin. The influence of clinically occurring SHb fractions on the internationally standarized total haemoglobin determination were shown to be insignificant.

Ferricyanides↗
PubMed1976

Quality control in haemoglobinometry with special reference to the stability of haemiglobincyanide reference solutions.

In haemoglobinometry grave errors are still being made even though an internationally accepted standardized method is available for the determination of the haemoglobin content of blood. Up to the present only haemiglobincyanide reference solutions have been available on a wide scale to check the measuring stage of the standardized haemiglobincyanide method. These reference solutions are shown to remain stable, under proper storage conditions, for more than 10 years. Concentrated haemoglobin solutions have become available recently, offering the possibility to control the dilution and conversion steps of the haemiglobincyanide method. Such a solution is shown to remain stable, under proper storage conditions, for at least a year. Using both haemiglobincyanide reference solutions and concentrated haemoglobin solutions, as well as having the possibility of checking the cyanide content of the reagent used, an acceptable intra-laboratory control program may now be set up.

Cyanides↗