M. El Allaf

Quantitative turbidimetric assay for determining myoglobin evaluated.

A recently introduced turbidimetric immunoassay using shell/core particles for determination of myoglobin (Turbiquant Myoglobin, Behringwerke, Marburg, Germany) was evaluated on the Behring Turbitimer analyzer. Intra-assay CV varied between 1 · 0% and 3 · 2%; interassay CV was between 2 · 0% and 3 · 6%. Linear results were obtained between 2 · 8 nmol/L and 36 · 7 nmol/L. Manual dilution in saline solution allowed measurement of myoglobin concentrations up to 25 400 nmol/L. In the tested range, no high-dose ‘hook’ effect was observed. Haemolysis interfered with the assay when haemoglobin concentrations exceeded 2 g/L. The occurrence of error codes due to the presence of triglycerides was shown to depend on particle size. Repeat assays on diluted samples were necessary at triglyceride concentrations of 2 · 3 mmol/L for post-prandial chylomicrons (200–1000 nm), and at 11–31 mmol/L for very-low density lipoprotein-triglycerides (80–200 nm). No significant interferences of haptoglobin, bilirubin, iodine containing contrast media, and rheumatoid factors were detected for the assay. Treatment of lipaemic samples with Lipoclean (Behringwerke) resulted in lower myoglobin values. Simultaneously drawn serum and heparin-plasma samples gave comparable myoglobin results. However, values obtained in EDTA- or citrate-treated plasma samples occasionally differed significantly from serum values. The upper reference limit for myoglobin concentration was 4 · 2 nmol/L. The turbidimetric assay correlated well with a radioimmunoassay (Byk-Sangtec; r = 0 · 892) and with the automated nephelometric assay (Behringwerke; r = 0 · 944). Values obtained by turbidimetry were comparable to those obtained by the latex agglutination test (Behringwerke).

The value of serum CK-MB and myoglobin measurements for assessing perioperative myocardial infarction after cardiac surgery

In 41 patients who underwent coronary bypass surgery, creatine kinase (CK)-MB mass concentration was repeatedly measured in serum during and after the intervention using a new two-site immunoenzymetric assay (IEMA). Serum CK-MB activity was determined with the use of four different techniques: immunoinhibition, immunoinhibition-immunoprecipitation, column chromatography and electrophoresis. Myoglobin (Mb) was also measured in each specimen by radioimmunoassay. In the 33 patients who followed a completely uneventful postoperative course, the cumulated CK-MB release was, on the average, 12.2-fold less than after acute myocardial infarction. The CK-MB peak concentrations using the IEMA were 33 +/- 3 micrograms/l (X +/- SEM) and occurred 6.4 +/- 0.5 h after the intervention was started; CK-MB levels had decreased to 2.9 +/- 0.4 micrograms/l at the end of the first postoperative day. The evolution of the CK-MB concentration was parallel to that of the enzyme activity. The serum Mb maximum concentrations (518 +/- 39 micrograms/l) were reached after 3.3 +/- 0.1 h. The other eight patients developed perioperative myocardial infarction (PMI); in this group, the cumulated CK-MB release was higher, and the serum CK-MB postoperative curves were of three different types. The patients with delayed CK-MB peaks (type I pattern) or sustained elevations (type III) of this isoenzyme also showed increased serum Mb levels at the end of the first postoperative day. The PMI patients with early (10 h) CK-MB elevations (type II) did not demonstrate abnormal serum Mb levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved Detection of Perioperative Myocardial Infarction After Cardiac Surgery Using CK-MB Mass Measurements

After coronary bypass surgery (CBS), late survival is reduced in patients who develop perioperative myocardial infarction (PMI) as compared with the uncomplicated cases [4, 8]. Therefore the improvement of individual therapy in these patients depends on our capacity reliably to select high-risk cases during the early postoperative period.

Role de l' alpha 1-glycoproteine acide plasmatique dans la fixation de l'aminopyrine.

AbstractUnder certain pathological conditions the binding of various substances by serum proteins is altered. The plasma concentrations of alpha, -acid glycoprotein, also known as orosomucoid are reported to be elevated in stressful situation and in certain disease states like acute myocardial infarction. The binding of aminopyrine to serum proteins and α1-acid glycoprotein was determined using equilibrium dialysis.It appears that α1-acid glycoprotein has specific binding sites for aminopyrine. Aminopyrine was also bound to other serum proteins. On addition the results indicate that an increase of α1-acid glycoprotein to concentrations such as those seen in some pathological states does not really alter the percent of aminopyrine bind to serum proteins.

Multiple Myeloma Assessment by Isoelectric Focusing in Patients with Apparently Increased Beta-Globulin on Cellulose Acetate Electrophoresis

Abstract In this study, thin-layer isoelectric focusing on polyacrylamide gel was used to analyze the immunoglobulin (Ig) fractions of patients with multiple myeloma who demonstrated a falsely increased β-globulin band on cellulose acetate electrophoresis.