Excretion of myoglobin in urine after actue myocardial infarction

Development of a multiplex mass spectrometry method for simultaneous quantification of urinary proteins related to respiratory health

Respiratory health of children is a health priority. Club cell protein (CC16) is an interesting biomarker of lung diseases and adverse effects towards the airway epithelium integrity. Osteopontin (OPN) and nuclear factor-kappa B (NF-κB) also play a role in respiratory health. The use of urine as biomarker source is useful in studies involving children but necessitates proper adjustment for physiological confounders influencing the urinary excretion, potentially characterized with beta-2-microglobulin (β2M), retinol binding protein 4 (RBP4) or myoglobin (MYO), as well as adjustment for possible renal dysfunction, characterized by human serum albumin (HSA). The simultaneous quantification of all these proteins in urine could facilitate children's health monitoring. A multiple reaction monitoring method (MRM) was developed and validated for the relative quantification of the seven mentioned urinary proteins. A total of nine proteotypic peptides were selected and used for the relative quantification of the seven proteins. The MRM method was completely validated for all proteins and partially for OPN. LOQ's ranged from 0.3 to 42.8 ng/ml, a good reproducibility and a good linearity were obtained across the analytical measurement range (r² > 0.98). The method yielded varying correlations (r² of 0.78, 0.71, 0.34 and 0.15 for CC16, β2M, RBP4 and HSA respectively) with available immunoassay data. It also allowed the identification and successful quantification of β2M and RBP4 as a protein candidate for adjustment of renal handling and dysfunction. All proteins were detected in the urine samples except for MYO and NF-κB. Our validated MRM-method is able to simultaneously quantify in urine biomarkers of airway epithelium integrity and biomarkers of variation in renal function and urinary dilution. This will allow to investigate further in future studies if urine can be used as a good surrogate source for biomarkers of airway epithelium integrity, and to understand the complex relationship between cause and effect in children's respiratory health monitoring.

Effects of intravenous streptokinase and CLS 2210 (calcium dobesilate) on the biochemical markers of early acute myocardial infarction: a historic comparison with both studies

In a previous double-blind, randomized study, CLS 2210 (a new formulation of calcium dobesilate) or placebo was administered by intravenous infusion to 41 patients having their first acute myocardial infarction. In the present study 19 comparable patients were treated intravenously with streptokinase under identical conditions and the results compared with those from the previous study. In all patients administration was begun within three hours of onset of symptoms and continued over seventy-two hours. Blood samples were taken for the measurement of serum activity of creatine kinase and its isoenzyme MB, and the serum and urinary concentrations of myoglobin and glycosaminoglycans were also measured. The purpose of this study was to determine the effects of CLS 2210, placebo, and streptokinase on these biochemical markers of acute myocardial infarction, thereby assessing their actions in limiting myocardial necrosis. In the CLS 2210-treated patients, the levels of serum creatine kinase and serum and urinary myoglobin were significantly lower than in the placebo patients throughout the seventy-two hours (p = 0.01, 0.005, 0.004 respectively). The levels of creatine kinase MB and serum glycosaminoglycan in the CLS 2210 patients were initially higher than in the placebo patients but fell below placebo levels between the fortieth and fifty-fifth hours, respectively (p = 0.89, 0.02). Only the glycosaminoglycan urinary concentrations were higher in the CLS 2210 group than in the placebo group throughout (p = 0.0005). The values for the six variables investigated showed no statistically significant difference between placebo and streptokinase.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum myoglobin, creatine kinase and creatine kinase-MB as mutually supportive indices of myocardial infarction and infarct size

A comparison was made between the appearance of serum myoglobin and creatine kinase in 22 patients with acute myocardial infarction who were admitted to a coronary-care unit within four hours of onset of chest pain. The MB isoenzyme of creatine kinase was measured in 12 patients. The more rapid appearance and disappearance of myoglobin relative to creatine kinase and creatine kinase-MB was confirmed, as was the correspondence between their respective peak values. A significant correlation was also obtained between the area under the myoglobin time-course and the respective peak levels. Whereas creatine kinase activity declined exponentially from a single peak, myoglobin appeared in multiple episodes inadequately represented by a single peak value and having no clear clinical correlation. The role of myoglobin as a diagnostic aid in myocardial infarction is probably limited to its ability to support creatine kinase and creatine kinase-MB as indices of infarct size.

Serum myoglobin after cardiac catheterisation

Study of 80 consecutive patients undergoing elective diagnostic cardiac catheterisation showed that after the procedure 25 (31%) developed myoglobinaemia. This was attributed to complications of the catheterisation in two. The remaining 23 had received premedication by intramuscular injection. In patients without intramuscular injections myoglobinaemia did not occur after uncomplicated cardiac catheterisation. The study did not support the proposition that cardiac catheterisation results in myocardial damage which can be detected by abnormalities of myoglobin but not by conventional indications of myocardial necrosis.

An enzyme-immunoassay for myoglobin in human serum and urine. Method development, normal values and application to acute myocardial infarction

An enzyme-immunoassay has been developed for the detection of myoglobin in human serum and urine which is specific, accurate, precise, and has a sensitivity of 3 ng/ml. When compared with radioimmunoassay, the enzyme-immunoassay gives markedly similar results. Sera from normal adults had a myoglobin concentration in the range 3-65 ng/ml, and 64% of the same group had detectable myoglobinuria (range 3-11.5 ng/ml). All of 8 patients with definite acute myocardial infarction had raised serum myoglobin levels (range 200-1125 ng/ml) either at admission or 4 h later. Myoglobin concentration returned to normal in 6 patients, and in the remaining 2 patients there was evidence of infarct extension. Urinary myoglobin excretion was variable. One patient with possible acute myocardial infarction had elevated serum myoglobin (413 ng/ml 4 h post admission) and 5 patients with no evidence of infarction had normal levels (15-53 ng/ml). The results suggest that detection of serum myoglobin by enzyme-immunoassay may be a valuable test in the early diagnosis of acute myocardial infarction.

Radioimmunoassays of human myoglobin in serum and urine

Two solid-phase radioimmunoassays have been developed for the detection of myoglobin in serum and urine. The sensitivity of the methods is 0.1 and 0.5 microgram/l, respectively, with a coefficient of variation of the respective method of 7-8%. The mean serum concentration of myoglobin in ninety-nine healthy blood donors was 44.3 microgram/l +/- 18.0 microgram/l (SD) with a significant difference (P less than 0.001) between men (50.6 +/- 19.8) and women (35.7 +/- 10.4). Serum myoglobin was positively correlated to age (P less than 0.05), body weight (P less than 0.02), serum creatine kinase (P less than 0.001), and serum creatinine (P less than 0.001) to galactose elimination rate. Serum myoglobin levels were not influenced by exhaustive short time dynamic exercise. The mean urinary excretion of myoglobin in twenty-four healthy students was 1.2 microgram/24 h (range 0.1-4 microgram/24 h). Myoglobin excretion was correlated to excretion of beta 2-microglobulin (P less than 0.02) but not to serum levels of myoglobin. No indications of circulating antibodies to myoglobin were obtained when assaying sixty-seven rheumatoid arthritis and thirteen myastenia gravis sera. Presence of other myoglobin binding substances in serum, which would interfere with the assays also seemed unlikely. Determination of myoglobin in serum by sensitive and specific method might be of clinical value in the diagnosis of diseases involving muscle tissues.

Excretion of myoglobin in urine after cardiac catheterisation

Myoglobin levels were assayed in each urine specimen voided during 12 hours before and 48 hours after routine cardiac catheterisation in 146 patients using an indirect haemagglutination method detecting concentrations in excess of 0.015 mg/ml. Myoglobinuria was found in only one patient before but in 39 patients after cardiac catheterisation (27%), either in the first (34 patients) or the second (5 patients) post-catheterisation urine sample. Once detected, myoglobin was present in all subsequent urine specimens for the next 3 to 22 hours (mean 11.8 hours). The mean amount excreted +/- SE was 14.0 +/- 1.6 mg (range 2.6 to 30 mg) excluding the one patient with myoglobinuria before catheterisation. This patient, who had severe aortic stenosis and atherosclerotic heart disease, excreted 130 mg myoglobin. Patients with myoglobinuria required longer screening time to complete the procedures undertaken than those in whom myoglobin was not detected--15.6 +/- 1.4 and 11.1 +/- 0.6 minutes, respectively (mean +/- SE:P less than 0.01). We conclude that myoglobinuria is not uncommon after cardiac catheterisation, and that though the myoglobin detected may be released from skeletal muscle, it could be partly or wholly of cardiac origin and indicate transient, and presumably reversible, myocardial injury.