Differentiating muscle damage from myocardial injury by meaans of the serum creatinine kinase (CK) isoenzyme MB mass measurement/total CK activity ratio

We immunoenzymometrically measured creatine kinase (CK) isoenzyme MB in extracts of myocardium and in homogenates of five different skeletal muscles. CK-MB concentrations in the former averaged 80.9 micrograms/g wet tissue; in the skeletal muscles it varied widely, being (e.g.) 25-fold greater in diaphragm than in psoas. CK-MB in skeletal muscles ranged from 0.9 to 44 ng/U of total CK; the mean for myocardium was 202 ng/U. In sera from 10 trauma and 36 burn patients without myocardial involvement, maximum ratios for CK-MB mass/total CK activity averaged 7 (SEM 1) ng/U and 18 (SEM 6) ng/U, respectively. Except for an infant (220 ng/U), the highest ratio we found for serum after muscular damage was 38 ng/U. In contrast, the mean maximum ratio determined in 23 cases of acute myocardial infarction exceeded 200 ng/U. Among seven determinations performed 8 to 32 h after onset of symptoms, each infarct patient demonstrated at least one ratio greater than or equal to 110 ng/U. Ratios observed after infarct were unrelated to treatment received during the acute phase. We propose a CK-MB/total CK ratio of 80 ng/U as the cutoff value for differentiating myocardial necrosis from muscular injury

Further heterogeneity demonstarted for serum creatine kinase isoenzyme MM

Serum creatine kinase (EC 2.1.3.2) isoenzyme MM was resolved by isoelectric focusing into a five-band pattern, a pattern that gradually changed after the onset of myocardial infarction. Similar changes were also demonstrated in patients undergoing coronary-bypass surgery. The evolution of two CK-MB sub-bands was studied in both cases. We found that three electrophoretic bands (CK-MM, pI 7.10; MM1, pI 6.88; MB1, pI 5.61) were predominant in patterns for sera collected during the early phase of myocardial infarction, but rapidly disappeared during the following hours, whereas bands of increased electrophoretic mobility (MM2, pI 6.70; MM3, pI 6.45; MM4, pI 6.25; MB2, pI 5.34) gradually increased. MM3 was always the major band at the end of the observation period in acute myocardial infarction (mean, 61.4% of total creatine kinase activity 36 h after the peak value for total creatine kinase in serum). The CK-MM bands were also present in the serum of patients without heart disease. Changes in the electrophoretic pattern were induced by a thermolabile factor in normal human serum, which transformed the muscular or myocardial MM and MM1 bands after their release into the blood strea

Semi-quantitative estimation of serum myoglobin by a rapid latex agglutination method: an emergency screening test for acute myocardial infarction.

The present study reports the evaluation of a new latex agglutination test for serum myoglobin (SMb). The time of agglutination of the latex particles coated with antibodies to myoglobin was measured in 172 serum specimens with known concentration of myoglobin quantitated by a radioimmunoassay (RIA), collected from myocardial infarction (MI) patients, subjects suffering from various diseases, and normal controls. Myoglobin levels in the samples were found to decrease exponentially with time of agglutination. Agglutination occurring within 1 min (result coded as + + + +) corresponded to 761 +/- 366 micrograms/l of myoglobin; between 1 and 2 min (+ + +), to 285 +/- 101 micrograms/l; between 2 and 3 min (+ +), to 85 +/- 47 micrograms/l; between 3 and 4 min (+), to 51 +/- 38 micrograms/l; and after more than 4 min (-), to 31 +/- 16 micrograms/l. Blood samples were serially drawn from 24 MI patients with short hospitalization delays; the rapid agglutination which was obtained in the specimens taken upon admission (20 results coded as + + + + and four as + + +) actually corresponded to markedly increased SMb levels. In contrast, serum creatine kinase (CK) activities were still less than 150 U/l in four patients (16.6%); CK-MB was less than 5 U/l in five cases (20.8%). Positive agglutinations for SMb were also obtained 4 and 8 h following admission in all subjects, confirming that the latex test is an early and very sensitive indicator for MI.(ABSTRACT TRUNCATED AT 250 WORDS

Approche méthodologique pour la démonstration d'un effet hépato-protecteur chez l'homme

peer reviewe

The protection of creatine kinase MM sub-bands by EDTA during storage.

We examined the effect of a 5 mmol/l concentration of EDTA on the stabilization of the five serum creatine kinase MM isoenzymes, resolved by thin-layer isoelectric focusing. In patient sera, total CK and CK-MB activities were stable during storage of the samples for two months at 4 degrees C even in the absence of EDTA. However, EDTA stabilized the labile MM and MM1 sub-bands, which are the first to appear in the blood after the release from the damaged tissue and its addition to blood samples intended for determining the MM sub-band pattern is recommended. The stabilizing effect of EDTA was emphasized at higher temperatures. EDTA protected the CK-MM pattern in myocardium extracts made in normal serum and incubated at 37 degrees C during 40 h, but was unnecessary when myocardium was homogenized in heat-inactivated serum. It is thought that EDTA could act by inhibiting a heat-labile component of human serum