Patterns of lactate dehydrogenase isoenzymes 1 and 2 in serum of patients performing an exercise test.

1989 ◽  
Vol 35 (2) ◽  
pp. 301-303 ◽  
Author(s):  
Z Rotenberg ◽  
I Weinberger ◽  
A Sagie ◽  
J Fuchs ◽  
E Davidson ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Exercise Test ◽  
Test Results ◽  
Normal Range ◽  
St Depression ◽  
Negative Results ◽  
Ratio Determination ◽  
The Mean ◽  
Lactate Dehydrogenase Isoenzymes

Abstract Values for total lactate dehydrogenase (LD, EC 1.1.1.27) activity and LD isoenzymes were determined in serum from 56 patients and 40 healthy subjects before and 24, 48, and 72 h after they performed an exercise test. The mean (for all four times) total LD activity concentration and proportion of LD-2 were within the normal range for all 96 subjects. Mean LD-1 values for serum, although within the normal range in all subjects, were significantly higher in patients with positive exercise test results than in subjects with negative results: 75 (SD 12) U/L in 35 patients with ST depression greater than 2 mm; 63 (SD 14) U/L in 16 patients with ST depression of 1-2 mm; 43 (SD 11) U/L in subjects with negative test results, by 48 h after the test. The LD 1:2 ratio was also markedly higher in the group of patients with positive test exercise results, especially in those with ST depression greater than 2 mm (1.02, SD 0.06), compared with those subjects with negative results (0.60, SD 0.04). A similar trend was also found 24 and 72 h after the exercise test. We conclude that exercise-myocardial ischemia may lead to an increased LD 1:2 ratio in serum, and demonstrate a correlation between the degree of ischemia and the LD 1:2 ratio. Determination of the LD 1:2 ratio, even in the presence of normal total LD activity, may assist in the clinical evaluation of patients performing an exercise test.

Lactate dehydrogenase isoenzymes in serum during unstable angina.

1986 ◽  
Vol 32 (8) ◽  
pp. 1566-1567 ◽  
Author(s):  
Z Rotenberg ◽  
I Weinberger ◽  
A Sagie ◽  
J Fuchs ◽  
O Sperling ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Lactate Dehydrogenase ◽  
Unstable Angina ◽  
Stable Angina ◽  
Myocardial Damage ◽  
Functional Evaluation ◽  
Normal Range ◽  
The Mean ◽  
Lactate Dehydrogenase Isoenzymes

Abstract Values for total lactate dehydrogenase (LD, EC 1.1.1.27) activity in serum, LD isoenzymes 1 and 2, and the LD 1:2 ratio in 25 patients with unstable angina were compared with the same variables in 25 patients whose angina was stable 24, 48, and 72 h after admission. Mean total LD activity and mean LD-2 activity were found to be within the normal range, both in the unstable angina and stable angina groups of patients. In the unstable angina group the mean LD-1 was significantly higher (p less than 0.01) than in the stable angina group at each time studied. The mean LD 1:2 ratio was also significantly different (p less than 0.001) between the two groups of patients. In the unstable angina group of patients the ratio was increased (0.85, SD 0.09), as in patients with acute myocardial infarction, whereas in the stable angina group of patients the ratio was normal (0.60, SD 0.06). We conclude that a high LD 1:2 ratio, even in the presence of normal total LD activity, may indicate myocardial damage in some patients with unstable angina and could therefore help in the clinical and functional evaluation of patients with unstable angina.

Optimal α-Oxobutyrate Concentration for Assay of α-Hydroxybutyrate Dehydrogenase Activity in Normal and Pathological Sera at 30 °C

1974 ◽  
Vol 20 (4) ◽  
pp. 494-496 ◽  
Author(s):  
Leslie M Shaw ◽  
Jane Gray
Keyword(s):  
Myocardial Infarction ◽  
Liver Disease ◽  
Lactate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Substrate Concentration ◽  
Optimal Concentration ◽  
The Mean

Abstract Optimal concentration of substrate, α-oxobutyrate, for determination of α-hydroxybutyrate dehydrogenase (HBD) activity in normal and pathological sera at 30 °C (with a centrifugal analyzer) is 12 mmol/ liter. With this substrate concentration, HBD activity averaged 146% of that found with the suboptimal concentration, 3.3 mmol/liter, usually used. Furthermore, day-to-day precision was significantly better. HBD/LD ranges (LD, lactate dehydrogenase), determined for sera from patients with myocardial infarction and liver disease, did not overlap and were similar to those established by Elliot et al. [Clin. Sci. 23, 305 (1962)], who used a suboptimal α-oxobutyrate concentration of 3.3 mmol/liter at 25 °C. At 30 °C the mean HBD/LD ratios for sera from patients with myocardial infarction were most different from those for patients with liver disease when the optimal concentration of α-oxobutyrate was used.

Colorimetric Method for Rapid Determination of Serum Arginase

1967 ◽  
Vol 13 (10) ◽  
pp. 900-908 ◽  
Author(s):  
Brigitta Mellerup
Keyword(s):  
Rapid Determination ◽  
Colorimetric Method ◽  
Normal Range ◽  
Clinical Routine ◽  
Mean Values ◽  
Enzymatic Formation ◽  
Significant Difference ◽  
The Mean ◽  
Normal Men

Abstract A method for the determination of serum arginase is given which combines the enzymatic formation of urea with the sensitive method of Coulombe (1) for measuring this substance. This procedure allows more accurate determinations in the normal range than do previous methods described and is convenient for clinical routine. Significant difference is found between the mean values of normal men and women, 3.9 units/L. for the former and 2.9 units/L. for the latter.

Automated kinetic determination of lactate dehydrogenase isoenzymes in serum.

1977 ◽  
Vol 23 (10) ◽  
pp. 1928-1930 ◽  
Author(s):  
L H Bernstein
Keyword(s):  
Lactate Dehydrogenase ◽  
Kinetic Method ◽  
Previous Method ◽  
Kinetic Determination ◽  
Steady State Kinetic ◽  
Enzyme Subunits ◽  
Isoenzyme Composition ◽  
State Kinetic ◽  
Lactate Dehydrogenase Isoenzymes

Abstract A steady-state kinetic method has been revised for measuring lactate dehydrogenase isoenzyme activities, which relates the inhibition of heart-type isoenzyme activity to the overall isoenzyme composition of the enzyme subunits. The method depends on the pH-dependent formation of an inhibitory ternary complex by the heart-type isoenzyme with NAD+ and pyruvate (if the reaction is measured by NADH oxidation). A preincubation step in the previous method is eliminated. The isoenzymes are measured by measuring the reduction of pyruvate in two different concentrations, which favor either the total or fractional activity, depending on the concentrations of pyruvate and the percentage of heart-type subunits. The method has been adapted to a centrifugal analyzer, which has speeded automated isoenzyme determinations, with an accuracy comparable to that for electrophoretic methods.

Ten electrophoretic methods compared with a selected method for quantifying lactate dehydrogenase isoenzymes in serum.

1988 ◽  
Vol 34 (9) ◽  
pp. 1885-1890 ◽  
Author(s):  
G C Moses ◽  
M L Ross ◽  
A R Henderson
Keyword(s):  
Lactate Dehydrogenase ◽  
Reference Method ◽  
Average Difference ◽  
Correlation Analyses ◽  
Different Types ◽  
Lactate Dehydrogenase Isoenzymes

Abstract Using the Selected Method of McKenzie and Henderson (Selected Methods Clin Chem 1983;10:59-67) as a reference method, we compared the performance of 10 commercially available methods for determination of lactate dehydrogenase (LD, EC 1.1.1.27) isoenzymes. Results were expressed as percentage of total LD activity, as determined with two different types of densitometers shown to have an average difference less than 1.4% for each isoenzyme. All methods gave generally comparable results, as judged by Bland-Altman plots and correlation analyses. However, in general, estimates by the commercial methods for LD-1, LD-2, and LD-3 were lower, and for LD-4 and LD-5 were higher than with the Selected Method. The overall CV was less than 20% for all methods and isoenzymes, except for LD-4 and LD-5 by the Beckman Paragon, Helena LD-VIS, Gel LDH, Gel PC, and Iso Dot, Gelman LDH Isozyme, and Sebia Hydragel assays, for which it was greater than 20%. Overall, accuracy was best with the Helena Iso Dot and LD-VIS assays, followed by the Corning LD Flur assay; accuracy was poorest with the Gelman LDH Isozyme, Sebia Hydragel, and Beckman Paragon assays.

scholarly journals Quantitative nephelometric assay for determining myoglobin evaluated

1990 ◽  
Vol 36 (9) ◽  
pp. 1675-1678 ◽  
Author(s):  
J R Delanghe ◽  
J P Chapelle ◽  
S C Vanderschueren
Keyword(s):  
Reliable Method ◽  
High Dose ◽  
Rheumatoid Factors ◽  
Test Results ◽  
Multiple Forms ◽  
Hook Effect ◽  
Tissue Extracts ◽  
The Mean ◽  
Serum Myoglobin

Abstract A recently introduced automated nephelometric immunoassay involving shell/core particles for determination of myoglobin (Behringwerke) was evaluated with the BNA Nephelometer. Method precision was good: the intra-assay CV varied between 1.5% and 6.1%; with daily calibration, the interassay CV ranged between 1.5% and 7.5%. For usual sample dilutions, the assay response varied linearly with myoglobin concentrations up to 23.1 nmol/L. After automatic dilution by the instrument, concentrations up to 2310 nmol/L could be measured without high-dose "hook" effect. Further manual dilution allowed measurement of myoglobin concentrations up to 26,000 nmol/L. Calibration was stable for at least seven days. We detected no significant interferences from hemoglobin, haptoglobin, bilirubin, iodine-containing contrast media, and rheumatoid factors. Treating lipemic samples with Lipoclean (Behringwerke) decreased test results. Simultaneously drawn serum and plasma samples from the same subject showed no consistent differences in myoglobin concentrations. The mean reference myoglobin concentration was 1.380 (SD 0.82) nmol/L for men and 0.878 (SD 0.45) nmol/L for women. In patients with renal insufficiency, serum creatinine values were moderately related to serum myoglobin values (r = 0.465). Although a commercial radioimmunoassay (Byk-Sangtec) and the nephelometric assay intercorrelated well (r = 0.929), values obtained by nephelometry were significantly lower (P less than 0.05). By both assays, results for heart and skeletal muscle tissue extracts showed no correlation, a finding that suggests the existence of multiple forms of myoglobin in human tissues. We conclude that immunonephelometry is a rapid, practical, and reliable method for measuring myoglobin in serum.

Information induction for predicting acute myocardial infarction.

1988 ◽  
Vol 34 (10) ◽  
pp. 2031-2038 ◽  
Author(s):  
R A Rudolph ◽  
L H Bernstein ◽  
J Babb
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Information Theory ◽  
Creatine Kinase ◽  
Lactate Dehydrogenase ◽  
Noisy Channel ◽  
Information Uncertainty ◽  
Test Results ◽  
Creatine Kinase Mb

Abstract We show how to make an unsupervised discrimination of disease and nondisease states by measuring information and using newer notions of inductive reason. We also present a new theory of group-based reference values that is based on measuring information uncertainty. We use data on the isoenzymes creatine kinase-MB (CK-MB) and lactate dehydrogenase-1 (LD1) and on the percentage of LD1 from 101 patients with acute myocardial infarction (AMI) and from 41 patients with suspected, but unfounded, infarction (non-AMI). Calculating the Shannon entropy, a concept from information theory, of the data base allows determination of a difference in entropy values ("effective information"), which determines decision cutoff values that produce binary-base patterns yielding the fewest classification errors. Redundancy in testing is important because it provides the information to approach a goal of errorless discrimination by coding the test results and meeting the conditions of the "Noisy Channel Theorem" of information theory. This redundancy improves the predictive value of diagnosis by isolating the area of equivocation to evident patterns. Results for CK-MB and LD1 are 99% correct in assigning cases to AMI and non-AMI categories; adding %LD1 increases the proportion of errorless binary patterns from 25% to 90%.

Lactate dehydrogenase and its isoenzymes in serum from patients with multiple myeloma.

1989 ◽  
Vol 35 (9) ◽  
pp. 1968-1970 ◽  
Author(s):  
S Copur ◽  
S Kus ◽  
A Kars ◽  
N Renda ◽  
G Tekuzman ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Prognostic Factors ◽  
Lactate Dehydrogenase ◽  
Clinical Status ◽  
Control Group ◽  
Healthy Controls ◽  
Newly Diagnosed ◽  
The Mean ◽  
Isoenzyme Patterns

Abstract Concentrations of total lactate dehydrogenase (LDH; EC 1.1.1.27) and LDH isoenzyme patterns were studied in serum of 19 patients with multiple myeloma and in 19 healthy controls. Patients were divided into three groups (pretreatment, nonresponders, and responders to treatment), based on their clinical status at the time of blood sampling for LDH. The LDH values were found to be significantly higher (P less than 0.05) in the pretreatment group and in the nonresponders than in the responders and the control group, the mean +/- SE values being 445 +/- 35 and 532 +/- 75 units/mL vs 349 +/- 75 and 190 +/- 7.1 units/mL, respectively. Compared with responders and healthy controls, newly diagnosed patients and nonresponders had slight diminutions in LDH-1 and LDH-2, but increased LDH-3. We conclude that determination of LDH and its isoenzymes in serum can be of value as prognostic factors in patients with multiple myeloma.

Method variation in lactate dehydrogenase isoenzyme determination.

1981 ◽  
Vol 27 (4) ◽  
pp. 624-625 ◽  
Author(s):  
N M Papadopoulos
Keyword(s):  
Myocardial Infarction ◽  
Lactate Dehydrogenase ◽  
Test Results ◽  
Dehydrogenase Isoenzyme ◽  
Lactate Dehydrogenase Isoenzymes

Abstract Differences between methods for determining lactate dehydrogenase isoenzymes are illustrated, which can account for discrepant results. They should be taken into consideration in the interpretation of test results for the diagnosis of myocardial infarction.

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