Cardiac troponin I to diagnose myocardial injury.
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Biomedical subjects
Publications and source records attributed to C Calzolari.
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Peculiar dorsal neurons present in the dorsal spinal cord of Trigla lucerna L. and Scorpaena porcus L. were investigated by neuroanatomical and immunohistochemical methods. These neurons were previously defined as commissural cells, but have now been identified as supramedullary neurons. The following fundamental criteria for identifying the supramedullary neurons of Teleosts are proposed: a) dorsomedial location in the spinal cord; b) large size of the soma and axon; c) immunoreactivity to gastrin/CCK-like peptides.
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The screening by immunoenzymometric assay (IEMA) of 784 monoclonal antibody (MAb) combinations resulted in the selection of an optimal pair of MAbs for measuring human cardiac troponin I (TnI). Using a one-step IEMA described here, we were able to detect TnI within the range of 0.2-20 micrograms/L in 30 min at room temperature. No cross-reactivity was observed with the skeletal isoforms of troponin up to a concentration of 500 micrograms/L. This assay was used to measure cardiac TnI in the plasma of 43 patients with acute myocardial infarction (AMI). TnI was detected relatively early after the onset of chest pain (4.3 +/- 2.1 h, mean +/- SD); the peak occurred after 12.2 +/- 4.6 h in a population that had undergone fibrinolysis. TnI disappearance was generally observed between 5 and 9 days after the onset of chest pain. No cardiac TnI could be detected in 145 healthy donors or in a control group of 6 patients (with skeletal damage or rhabdomyolysis). This assay allows a specific diagnosis of AMI in its early acute phase, with a high diagnostic specificity and sensitivity.
Forty monoclonal antibodies (MAbs) specific for human cardiac troponin I (TnI) were selected to develop a new alternative for specific biological diagnosis of acute myocardial infarction. Using an immunoenzymatic sandwich assay, these MAbs were employed in the mapping of human cardiac TnI and showed six different epitopes. Parts of the TnI peptide sequences were synthesised; the sequences were chosen from the published sequences of mammalian TnI. Immunological assays showed that 8 out of 40 MAbs recognised a RAYATEPHAK (P2) N-terminus cardiac-specific sequence of human TnI. The information obtained from epitopic mapping of TnI and the properties of the peptides allowed pairs of MAbs to be selected for the development of a future specific TnI assay.
Estimation of the extent and location of infarct is important for the prognosis and hence therapeutic strategy in patients with acute myocardial infarction (AMI). Because cardiac myosin is the major structural protein of the myocardium, and may thus reflect the extent of injured tissue, we established a new sensitive immunoradiometric assay, using a pair of monoclonal antibodies (Mabs) that specifically bind the myosin heavy chain fragments liberated from the myocyte into plasma after a heart attack. A first Mab is linked to a magnetic solid phase. A second Mab, radiolabeled with 125I, is used to detect myosin trapped on the solid phase by the first Mab during a 3-h incubation. This assay can detect 10 micro-units of myosin per liter and is highly reproducible.
To evaluate the correlation between myosin heavy chain release and the necrosis mass, serum levels of myosin heavy chain fragments were determined serially in 55 patients with acute myocardial infarction. Eight of these patients were successfully treated with thrombolytic agents: the others were not treated. The same myosin titration was applied to the sera of 25 dogs with an experimental myocardial infarction. Six of the dogs were successfully treated with thrombolytic agents. The time courses of the myosin concentrations are typical and monophasic for all patients with a noncomplex myocardial infarction. The values for the kinetic parameters of myosin release are comparable to those previously reported. We have now determined that cumulative myosin release significantly correlates with cumulative creatine kinase (CK), CK-MB, and lactate dehydrogenase release, as well as with thallium-201 distribution, as determined for different patient groups. Thrombolytic treatment does not seem to qualitatively upset myosin kinetics. The results obtained in dogs with or without thrombolysis conclusively indicate that myosin release is a quantitative index of the necrosis mass. From a practical point of view, a few serial determinations of serum levels of myosin heavy chains are enough to estimate the necrosed mass in patients with acute myocardial infarction. More generally, serum myosin titration could be useful in detecting any cardiac disturbance involving myocardial injury resulting in membrane leakage of cardiac cells.
Sixty-five samples of human milk obtained from individual donors living in Rome and surrounding areas between 1982 and 1984, and 28 samples from Florence and surrounding areas obtained during 1985 were analyzed for residues of p,p'-DDE, p,p'-DDT and PCBs. Levels of p,p'-DDE were between 5 and 126 ppb (micrograms/kg of milk), with an average value of 45 ppb (median 34). Levels of p,p'-DDT ranged from 1 to 79 ppb, with an average value of 10 ppb (median 7). PCBs were found at levels ranging from 7 to 304 ppb, with an average value of 74 ppb (median 66). As to the p,p'-DDT, when compared to the data previously obtained in Italy during 1975-77, the present findings show a decrease of the average value and a lower incidence of samples with higher values. These effects are less pronounced for the p,p'-DDE. No relevant variation was observed in the levels of PCBs in comparison with the data obtained in Italy during 1981-82.
Plasma levels of ventricular myosin fragments, determined with monoclonal antibodies to myosin heavy chains, were studied in 27 patients after cardiac operations (17 aorta-coronary bypass grafts and 10 valve replacements) to assess their possible role as a marker of perioperative myocardial necrosis. Five patients had perioperative myocardial necrosis after aorta-coronary bypass grafts as indicated by changes in the electrocardiogram and elevated levels of the MB isoenzyme of creatine kinase. Six more patients were also studied after thoracic operations performed by the same sternotomy approach. After cardiac operations, myosin levels increased from postoperative day 3 and reached peak values on day 7. Peak myosin values in patients with perioperative myocardial necrosis after aorta-coronary bypass grafting were significantly higher than in patients after an identical operation but without perioperative myocardial infarction (3793 +/- 592 versus 369 +/- 47 ng/ml; p less than 0.001). These results suggest that plasma myosin is a sensitive marker of myocardial necrosis. Furthermore, peak plasma levels of ventricular myosin after coronary bypass grafting without myocardial infarction (mean value 369 +/- 47 ng/ml) were not significantly different from peak levels after thoracic operations (mean value 253 +/- 52 ng/ml), whereas they were significantly higher after valve replacement (mean value 794 +/- 149 ng/ml; p less than 0.01). These results indicate that a certain degree of myocardial necrosis occurs during value replacement that is undetectable by the usual diagnostic criteria for perioperative myocardial infarction. We conclude that the plasma level of ventricular myosin fragments is a more specific and accurate marker of perioperative myocardial necrosis than changes in the electrocardiogram or elevated creatine kinase MB levels. Therefore the detection of myosin fragments, which appear in the serum on the third day after cardiac operations, may be useful for precise comparisons of different techniques of myocardial protection.
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The radiological manifestations of an unusual spondyloepiphyseal dysplasia have been observed in a girl. A peculiar epi-metaphyseal involvement that is "cone shaped epiphyses" appears to be the major feature.
Following acute myocardial infarction, fragments of human cardiac myosin can be detected in plasma by means of monoclonal antibodies to myosin heavy chains from the left human ventricle. The cumulative amounts of myosin released during the first 9 post-infarction days are proportional to the size of the infarct (Tao Ming et al., in the press). The purpose of our study was to evaluate the effectiveness of a fibrinolytic treatment administered in the acute phase of myocardial infarction by measuring in the plasma, the circulating fragments of human cardiac myosin. Three groups of patients with acute myocardial infarction were investigated: 13 patients (group A) received a conventional treatment; 8 patients (group B) were treated with intravenous streptokinase without success, i.e. with persistence of the coronary occlusion; 9 patients (group C) were successfully treated with intravenous streptokinase, resulting in recanalization of the coronary artery. We found that the cumulative amount of myosin released during the first 9 post-infarction days was significantly lower in patients successfully treated with streptokinase [group C: (3.8 +/- 2.3) 10(3) ng/ml/day]. There was no difference in cumulative release of myosin between control patients [group A: (7.0 +/- 3.3) 10(3) ng/ml/day] and patients with unsuccessful fibrinolytic treatment [group B: (10.0 +/- 4.1) 10(3) ng/ml/day]. These results were unrelated to the localisation of the infarct. It is concluded that measuring the cumulative amounts of myosin released is a means of evaluating the effectiveness of fibrinolytic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)
Recently we developed an enzyme immunoassay involving the use of steroid delta-isomerase (EC 5.3.3.1) as enzyme label and exclusion-affinity chromatography for rapid separation of free antigen-enzyme conjugate that bound to antibodies (J. Immunol. Methods 35: 267-284, 1980). Here we describe an automated version of this procedure, for immunoassay of progesterone and choriomammotropin (human placental lactogen) in serum with the use of a centrifugal analyzer. After incubation, suitable dilutions of sera or extract plus antiserum, conjugate, and double antibody were filtered on an estradiol affinity gel-filtration column; the enzyme activity of the filtrates was determined with the centrifugal analyzer. Results correlate well with those obtained by radioimmunoassay: r (progesterone) = 0.980, r (choriomammotropin) = 0.940. The within-run and between-run precision, specificity, sensitivity, accuracy, and speed of this system make it a useful tool for immunoassay.
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The authors tested the efficiency of clonidine as a stimulant for growth hormone (GH) release in a group of 31 undersized children aged from four to fourteen years. The efficacy of clonidine was compared with insulin-induced hypoglycaemia, which has so far been considered the most valid test for somatotropic function measurement. The average GH peak after clonidine was 13.7 +/- 1.9 ng/ml, while after insulin it was only 7.0 +/- 0.9 ng/ml. The number of patients responding to clonidine and insulin reacting with GH values below 5, between 5 and 8, and higher than 8 ng/ml were reported, and the difference between the two sets of values was found to be statistically significant (p less than 0,01) in favour of clonidine.
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Explore the source record for details and available documents.