LDH Ratio Research Articles

Distinguishing pleural transudates and exudates through the quantification of biochemical parameters

1) to evaluate the possibility of distinguishing pleural transudates and exudates through the joint determination of 26 biochemical parameters in pleural effusion and in plasma (including the determination of high molecular weight proteins, acute phase reactants, and proinflammatory citokines), and 2) to formulate a logistic regression equation for optimizing the classification efficiency, comparing the equation obtained with Light's criteria. All diagnostic thoracocentesis carried out in La Rioja Autonomous Community during a 22-month period were evaluated. The 245 clinical records were evaluated periodically along a minimum of 2 years, after the discharge of the patients. In pleural effusion and in plasma the following were quantified: total proteins, LDH, glucose, amylase, cholesterol, albumin, cholinesterase, phosphatase alkaline, urea, beta2-microglobulin, IgG, IgM, alpha2-macroglobulin, C reactive protein, transferrin, alpha1-antitrypsin, serum amyloid A protein, interleukin 1-beta, interleukin 6, tumoral necrosis factor-alpha, and lysozyme. In addition, the cellularity, polymorphonuclear elastase and adenosine deaminase were evaluated in pleural fluid. The LDH pleural effusion/plasma ratio was the individual parameter that showed higher area under the receiver operating characteristic curve for the separation of pleural transudates and exudates. Interleukin 6 and tumoral necrosis factor-alpha showed pleural effusion/plasma ratios higher than the unit, which suggests an in situ citokines production. An predictive logistic regression equation was obtained that incorporates only LDH and cholesterol ratios, including the diuretic treatment of the patient at the time of thoracocentesis, which did not modify the protein concentrations in pleural effusion. Except for LDH ratio, the logistic regression equation showed an area under the receiver operating characteristic curve higher than that of all the evaluated individual parameters, with a sensitivity of 95% and a specificity of 85% (70% for the Light's criteria). LDH ratio is the best individual parameter for distinguishing pleural transudates and exudates. The additional evaluation of cholesterol ratio and of the diuretic state of the patient make possible to improve the clinical efficiency of this classification. The quantification of high molecular weight proteins, acute phase reactants and citokines does not contribute additional significant information.

Diagnostic Utility of MAGE Expression in Exudative Pleural Effusion

Background : In recent years, numerous human tumor specific antigens such as melanoma antigen gene(MAGE) that is recognized by autologous cytotoxic T lymphocytes have been identified. MAGE is expressed in many human malignancies in various organs, such as lung, breast, stomach, esophagus and leukemia. Therefore MAGE has been studied widely for tumor diagnosis and immunotherapy. But, so far there were no clinical studies evaluating the role of MAGE in pleural effusion. We investigated the expression of MAGE in the patients with exudative pleural effusion for it's diagnostic utility and the results were compared with those of cytologic examinations. Methods : Diagnostic thoracentesis was performed in 44 consecutive patients with exudative pleural effusion during 6 months. We examined the expression of MAGE and cytology with the obtained pleural effusion. Expression of MAGE was interpreted by means of a commercial kit using RT-PCR method. Enrolled patients were divided into two groups such as malignant and benign and we analyzed its' sensitivity and specificity. Results : There were no significant differences between two groups in age, sex, white blood cell counts in pleural fluid, pleural fluid/serum protein ratio and pleural fluid/serum LDH ratio. The sensitivity and specificity of MAGE were 72.2% and 96.2% respectively and the positive predictive value and negative predictive value of MAGE were also 92.9% and 83.3% respectively. The sensitivity and negative predictive value of cytologic examinations were 66.7% and 81.3% respectively. There were no significant differences between sensitivities of MAGE and cytologic examinations but false positive result of MAGE was found in 1 case of tuberculous pleurisy. Conclusion : MAGE is a sensitive and specific marker for the differential diagnosis between benign and malignant effusion in patients with exudative pleural effusion. And MAGE would provide the equal sensitivity compared with that of cytologic examination in patients with malignant pleural effusion if 5mL of the pleural fluid is examined.

The LDH ratio as a marker for response to plasma exchange in HUS/TTP of the adult.

Plasma exchange improved the outcome of thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS) of the adult markedly, but a high number of non-responders remain. Identifying these patients at an early stage would help to optimize therapy. determine the value of serologic measures in predicting the response to plasma exchange. We performed a retrospective chart review of 30 patients with HUS/TTP of the adult treated with plasma exchange. According to the treatment protocol, a mean of 42 +/- 8.2 ml plasma per kilogram of body weight was exchanged daily for 3 days and continued every second day thereafter. Prior to each session, clinical status and serologic markers for hemolysis and kidney function were obtained. To assess the early individual response to plasma exchange, the decline of LDH from the first to the third cycle was calculated as: LDH concentration before the third session/LDH concentration before the first session (LDH ratio). During the observation period (median 195, range 6-1500 days), 80% of the patients responded to therapy with plasmapheresis. None of the serologic measures or clinical signs obtained before initiation of plasma exchange showed a significant correlation with the outcome. After 2 sessions of plasma exchange, only LDH and platelet level had improved markedly in responding patients. The LDH ratio was the best predictive marker for the individual response. An LDH ratio < 0.6 predicted a favorable outcome with a sensitivity of 0.96 and a specificity of 0.83. The LDH ratio might be a useful marker for separating patients responding to plasma exchange from those not responding at an early stage.

Is the pleural fluid transudate or exudate? A revisit of the diagnostic criteria

BACKGROUNDPleural effusions are classified into transudates and exudates based on criteria developed in the 1970s. However, their accuracy has not been evaluated. We compared the performance of the pleural fluid...

Therapeutic Management of Stage I–II High-Grade Primary Gastric Lymphomas

The best treatment for primary gastric lymphomas (PGL) has not yet been defined. Eighty-three patients with stage I/II PGL are documented, focusing on prognostic factors, treatment-related morbidity and mortality, and therapeutic outcome. Chemotherapy improved survival in comparison to local treatments, i.e. gastrectomy (n = 15) or gastrectomy and radiotherapy (n = 5). Patients treated with primary chemotherapy and/or radiotherapy (n = 21), with gastrectomy and chemotherapy (n = 26) or with gastrectomy and chemotherapy and radiotherapy (n = 16) showed a similar survival rate. Conservative treatment obtained a 5-year actuarial survival of 82% with a stomach preservation rate of 100%. Two treatment failures and 19 relapses (24%) were observed. Sixty patients (72%) are alive (59 no evidence of disease) at a median follow-up of 58 months. Ten-year actuarial survival is 64%. Local control was influenced by stage, tumor size, depth of infiltration, LDH ratio, and therapeutic modality, while age, stage, LDH ratio, and the use of chemotherapy had independent prognostic value. Because of its efficacy and safety, conservative strategy should be considered as first-line treatment for high-grade PGL. Gastrectomy should be indicated only for urgent cases, in which surgery followed by chemotherapy appears the best choice, followed by radiotherapy in patients with stage II₂ disease.

Ascitic fluid to serum bilirubin concentration ratio for the classification of transudates or exudates.

We compared the ascitic fluid to serum bilirubin ratio with three other ways of classifying ascitic fluid to the categories of exudate or transudate: the serum-ascites albumin gradient, the total protein concentration of the fluid, and the adaptation of Light's criteria for the detection of pleural fluid exudate, i.e., fluid to serum protein or LDH ratio or fluid LDH concentration. (Recently it has been reported that the pleural fluid to serum bilirubin ratio is statistically equivalent to Light's criteria.) Also, we evaluated whether the addition of the bilirubin ratio to the other criteria increases their diagnostic accuracy. Eighty-one specimens of ascitic fluid from 81 different patients were obtained. They were analyzed prospectively by SMA12, whereas the category of the fluid was determined according to the clinical diagnosis. The diagnostic accuracy of each criterion alone and in combination with the bilirubin ratio, with reference to the contended etiology, were evaluated. The best criterion is the albumin gradient (overall accuracy = 0.84). The bilirubin and LDH ratio criteria had equivalent overall accuracy (0.815 and 0.802, respectively). The addition of the bilirubin ratio to any criterion did not improve its predictive or overall accuracy. Ascitic fluid to serum bilirubin ratio is an additional marker for the distinction of transudate from exudate. A ratio > 0.6 has a statistically significant association with exudate.

Long-term effects of fatty acids on cell viability and gene expression of neonatal cardiac myocytes

Fatty acids are the most important source of energy for the adult heart. However, cardiac substrate preference changes during development and alters in pathophysiological states. Fatty acids have also been shown to be involved in signal transduction pathways, thereby affecting gene expression in various cell systems. In the present paper the significance of changes in substrate preference and the potential role of fatty acids in signal transduction in the cardiomyocyte are briefly reviewed. Furthermore, the development of a cellular model system, useful in exploring the long-term effects of fatty acids on the normal and hypertrophic cardiomyocyte, is described. Some aspects of this model system are illustrated by showing the effects of different fatty acid species on cell viability and the effects of fatty acids on the expression of heart type fatty acid-binding protein (H-FABP), a 15 kDa protein thought to be involved in intracellular trafficking of fatty acids. To this end primary cultures of rat neonatal ventricular myocytes were kept in defined medium containing various (combinations of) substrates for up to 48 h. First, the effects of prolonged exposure to different fatty acid species, complexed to BSA, on cell viability were investigated. Exposure of the cells to saturated fatty acids (C16:0 or C18:0), but not mono-unsaturated (C16:1 or C18:1) fatty acids, resulted in cell death, as evidenced by the release of intracellular proteins like lactate dehydrogenase. The detrimental effects of saturated fatty acids were nullified by the co-addition of mono-unsaturated fatty acids. Accordingly, the combination of C16:0 C18:1 was used to examine the effects of fatty acids on the expression of H-FABP. Therefore, the cells were incubated with either (i) glucose only, (ii) fatty acids only, or (iii) glucose plus fatty acids. Incubation with fatty acids (with or without glucose) resulted in a nearly four-fold increase of the H-FABP mRNA level. Similarly, at the protein level the cellular H- FABP LDH ratio increased almost two-fold. In hypertrophic cardiomyocytes (stimulated with the α 1-adrenergic agonist phenylephrine) the stimulatory effect of fatty acids on H-FABP expression was mitigated. These findings strongly suggest that fatty acids are able to modulate gene expression in the context of the cardiac muscle cell.

Significance of pleural fluid cholesterol and beta-2 microglobulin levels for the differentiation of pleural effusions in childhood.

We studied 60 children, ages 3-15 years, with pleural effusions to determine the usefulness of different criteria for the separation of transudates from exudates. Twenty of these effusions were classified as transudates and 40 as exudates. Pleural cholesterol (P chol), pleural/serum cholesterol ratio (P/S chol), and pleural/serum beta 2 microglobulin (P/S beta 2 m) were determined to characterize pleural effusions and were compared with Light's criteria (pleural/serum protein ratio, pleural LDH, pleural/serum LDH ratio). With a threshold of 0.3, the sensitivity and specificity of P/S chol for diagnosis of exudates were 95 and 90%, respectively. With a threshold of 1.3, the sensitivity of P/S beta 2 m was 77.5%, and its specificity was 95%. Our findings indicate that determination of P chol and P/S chol, as well as Light's criteria, is of value for characterizing pleural effusions in childhood, but the measurement of P/S beta 2 m is less sensitive in distinguishing transudates from exudates and it should not be used routinely.

Ultrasonography (US) a noninvasive method of assessment of the character of pleural effusion (PE)

The aim of this study was to investigate the pleural and systemic expression of interleukin-18 (IL-18) in patients with pleural effusions (PEs), and the effects of the cytokine in mouse pleural space.One hundred and sixty patients, 23 with pleural effusions (PEs) due to heart failure, 60 malignant, 25 parapneumonic/empyemas, 15 tuberculous and 37 with exudates of miscellaneous etiologies were included in the study. Pleural fluid (PF) and serum IL-18 content was determined using ELISA. IL-18 was injected intrapleurally in mice and pleural inflammation was assessed using pleural lavage.The highest PF IL-18 levels were observed in parapneumonic PEs and the lowest PF IL-18 levels in patients with exudates of miscellaneous aetiologies and transudates. PF IL-18 levels were significantly higher in patients with empyemas compared to those with uncomplicated (p = 0.009) or complicated (p = 0.028) parapneumonic effusions, while serum levels did not differ significantly among the three groups. Pleural IL-18 content was higher than that of blood only in patients with empyemas. In patients with pleural exudates of all etiologies and in those with parapneumonic PEs/empyema, PF IL-18 levels were correlated with markers of acute pleural inflammation such as the percentage of PF neutrophils, PF LDH and PF/serum LDH ratio, low PF glucose and PF/serum glucose ratio and low PF pH. In mice, intrapleural IL-18 caused neutrophil-predominant pleural inflammation.In conclusion, IL-18 is linked to the intensity of neutrophilic pleural inflammation in patients with PEs, it is up-regulated in the pleural space of patients with empyema and it stimulates the accumulation of neutrophils in mouse pleura.

&lt;b&gt;EFFECTS OF ANDROGENIC HORMONES ON THE EXPRESSION OF ISOZYMES OF LACTATE DEHYDROGENASE IN THE MASSETER MUSCLE AND TONGUE OF &lt;/b&gt;&lt;b&gt;MICE &lt;/b&gt;

Daily subcutaneous injections of 5α-androstane-3α, 17β-diol (5α-A-diol), testosterone or combination of both hormones into testectomized mice caused an increase in the muscletype LDH (LDH 5) activity reduced by testectomy, and induced the precocious appearance of the adult male-type distribution of LDH isozymes in developing mice. In adult mice, testectomy reduced the ratio of LDH 5 in the masseter muscle to the female level. Cyproterone acetate depressed the appearance of the male-type distribution of the isozymes in developing male animals. Moreover, in intact female mice, 5α-A-diol had a positive effect on shifting the isozyme distribution to the male type. In contrast, the distribution pattern of LDH isozymes in the tongue were not affected by any treatments

A diagnostic significance of pleural fluid cholesterol level.

The purpose of this study is to investigate the utility of the pleural fluid cholesterol level in separating the exudates from the transudates, and in differentiating tuberculous exudates from non-tuberculous exudates, 52 patients with pleural effusion were involved in this prospective study. By predefined criteria, 40 of these effusions were classified as exudates (Group I) and 12 as transudates (Group II). Group I was subdivided into tuberculous exudates (Group A) and non-tuberculous exudates (Group B). The followings are parameters used in separating the exudates from the transudates; pleural protein (P-PROT) 3.0 g/dl, pleural protein/serum protein ratio (P/S PORT) 0.5, pleural LDH (P-LDH) 200 IU, pleural LDH/serum LDH ratio (P/S LDH) 0.6, pleural cholesterol (P-CHOL) 50 mg/dl and pleural cholesterol/serum cholesterol ratio (P/S CHOL) 0.4. Mean values of the parameters in each group were compared, and then misclassified rate and the dignostic efficiency for each parameter were calculated. The results were as follows; 1) Mean P-CHOL () in Group I was higher than that () in Group II (p) in Group I was also higher than that () in Group II (p

Cholesterol: A Useful Parameter for Distinguishing between Pleural Exudates and Transudates

Previously established criteria were used to classify 253 pleural effusions as transudates (65 cases), neoplastic exudates (67 cases), tuberculous exudates (65 cases), or miscellaneous exudate (56 cases). The parameters pleural LDH (PLDH), pleural LDH/serum LDH ratio (P/SLDH), and pleural protein/serum protein ratio (P/SPROT) were compared with pleural cholesterol (PCHOL) and the pleural cholesterol/serum cholesterol ratio (P/SCHOL) with regard to their usefulness for distinguishing between pleural exudates and transudates. The PCHOL values determined were 28.5 +/- 12.8 mg/dl for transudates, 88.1 +/- 30 mg/dl for neoplastic exudates, 96.5 +/- 28 mg/dl for tuberculous exudates, and 88 +/- 35.9 mg/dl for the miscellaneous group; the differences between the transudate group and the others are statistically significant (p less than 0.001). The sensitivity and specificity of P/SPROT for diagnosis of exudates were both 89 percent; the sensitivity of PLDH was 67 percent and its specificity was 95 percent; the sensitivity and specificity of P/SLDH were both 84.6 percent. Using Light's three criteria as a battery, the sensitivity was 94.6 percent and its specificity was 78.4 percent. All the transudates and 17 (9 percent) of the 188 exudates had PCHOL values below 55 mg/dl, so that with this threshold, PCHOL had a sensitivity of 91 percent and a specificity of 100 percent for diagnosis of exudates. With a threshold of 0.3, P/SCHOL had a sensitivity of 92.5 percent and a specificity of 87.6 percent. The number of misclassifications by PCHOL was less than with any other of the parameters, with statistically significant differences with respect to PLDH (p less than 0.001) and P/SLDH (p less than 0.01). We conclude that determination of PCHOL and P/SCHOL is of great value for distinguishing between pleural exudates and transudates, and should be included in routine laboratory analysis of pleural effusions.

The effect of torbafylline on enzyme activities in fast and slow muscles with limited blood supply

1. Activities of a glycolytic enzyme—lactate dehydrogenase, LDH, and two oxidative enzymes—citrate synthase (CS), a marker for TCA cycle entry, and 3-hydroxyacyl-CoA dehydrogenase (HAD), which indicates the capacity for β-oxidation of endogenous lipids, were measured in fast (tibialis anterior, TA, and extensor digitorum longus, EDL) and slow (soleus, SOL) muscles of Sprague-Dawley rats with intact and limited blood supply, and following treatment with the xanthine derivative torbafylline (Hoechst, Werk Albert, Wiesbaden). 2. Limitation of blood supply by unilateral ligation of the common iliac artery increased activity of LDH in fast muscles, and activity of CS and HAD in soleus. 3. Torbafylline treatment caused an increased LDH activity in intact fast muscles and decreased it in soleus, although the relative capacity for anaerobic and aerobic metabolism (indicated by the ratio of LDH and CS activities) remained unchanged in all cases. 4. Whilst having little effect on oxidative enzyme activity of fast muscles, torbafylline decreased the activity of CS but increased activity of HAD in soleus, suggesting a greater reliance on lipid metabolism. 5. The effect of arterial ligation on enzyme activity was ameliorated by treatment with torbafylline, possibly due to its effect on the microcirculation.

The Serum-Effusion Albumin Gradient in the Evaluation of Pleural Effusions

The objective of the study was to compare the serum-effusion albumin gradient (serum albumin level minus pleural effusion albumin level) to Light's traditional criteria (pleural fluid/serum total protein ratio greater than 0.5, pleural fluid/serum LDH ratio greater than 0.6, and pleural fluid LDH greater than 200 U/L) for identifying exudative pleural effusions. The design included prospective measurement of the serum-effusion albumin gradient and Light's criteria in patients with pleural effusions in an inpatient ward in a military teaching hospital. Fifty-nine consecutive patients with pleural effusions who were undergoing diagnostic or therapeutic thoracentesis in whom the etiology of the effusion could be determined were studied. Serum and pleural effusion fluid chemistries were measured in order to determine both the serum-effusion albumin gradient and Light's criteria. Using an albumin gradient of 1.2 g/dl or less to indicate exudates and greater than 1.2 g/dl to indicate transudates, 57 of the 59 patients (41 exudates; 18 transudates) were correctly classified. Two patients with malignant effusions were misclassified as having transudates. Although Light's criteria correctly identified all of the exudates, five patients with congestive heart failure were misclassified as exudates. Four of these patients had had previous diuretic therapy, and all had a clinical response to further diuretic therapy. We conclude that although Light's criteria for exudates are very sensitive, an albumin gradient of 1.2 g/dl or less tends to be more specific, especially in cases of chronic congestive heart failure.

Pleural Fluid to Serum Bilirubin Concentration Ratio for the Separation of Transudates from Exudates

Whether fluid accumulating in the pleural space is a transudate or an exudate is determined by the widely used criteria of the pleural fluid to serum LDH and protein concentration ratios. Such a distinction is important for limiting the extent of the differential diagnosis of possible causes for this condition. We have found that a pleural fluid to serum total bilirubin ratio can serve the same purpose. The correlation of a bilirubin concentration ratio of 0.6 or more with the presence of an exudate as determined by established criteria is statistically highly significant; and its sensitivity, specificity, positive predictive accuracy, and overall accuracy in relation to etiology and LDH or protein criteria (Light's criteria) are about 90 percent. Hence, the bilirubin criterion is statistically equivalent to the widely accepted LDH and protein criteria.

Diagnostic value of ferritin measurements in patients with pleural effusions.

The diagnostic value of ferritin measurements has been evaluated in 59 patients with pleural effusions (PE). The Mean(+/- standard error [SE]) PE-ferritin level was 1913 +/- 720 ng/ml in 10 patients with nonmalignant nontuberculous (nonTB) exudates (Group I), 594 +/- 110 ng/ml in 14 patients with TB effusions (Group II), 1286 +/- 194 ng/ml in 28 patients with malignant exudates (Group III), and 280 +/- 60 ng/ml in 7 patients with transudates (Group IV). Significant difference was found between Group II and Group III (p less than 0.05). The mean (+/- SE) ratio of PE/serum (PE/S) ferritin in Groups I, II, III, and IV was 3.5 +/- 1.1, 10.5 +/- 5.1, 4.9 +/- 1.0, and 2.0 +/- 0.7, respectively, and it showed no significant difference among Groups I, II, and III. There were good correlations between PE-ferritin and PE-LDH or S-ferritin, but no correlation between PE-ferritin and PE-protein. PE-ferritin revealed a considerable overlap among the exudative groups, and was of no value in the differentiation between malignant and nonmalignant (Group I + II) exudates. In the discrimination between exudates and transudates, the diagnostic accuracy (86%) of PE-ferritin was inferior to those (all 98%) of PE-protein, PE-LDH, PE/S protein ratio, and PE/S LDH ratio. Using PE-ferritin greater than or equal to 500 ng/ml in distinguishing malignant exudates from TB effusions, the sensitivity was 79%, specificity 57% and accuracy 71%.(ABSTRACT TRUNCATED AT 250 WORDS)

Multifactorial analysis of parameters influencing chemosensitivity of human cancer xenografts in nude mice.

The results of single-agent chemotherapy, with 11 anticancer agents, of 15 human gastro-intestinal and breast cancer lines xenografted into nude mice indicate inherent individuality of chemosensitivity spectrum of each tumor. The following 9 parameters have been measured as factors possibly relevant to chemosensitivity of tumor tissue or tumor-bearing mice: grade of histological differentiation, vascularity, percentage of necrosis, VDT, 3H-thymidine LI, human LDH activity in the cancer tissue, tissue/serum LDH ratio, TdR Pase activity, and serum CEA. These parameters exhibited presumably constant values for each tumor line. Chemosensitivity, i.e., inhibition of tumor growth by a given drug, was used as the dependent variable, and values of the 9 parameters in each cancer as the explanatory variables. Multiple regression analyses with stepwise deletion were performed for each of the 11 drugs. The equations for 8 drugs exhibited coefficients of determination of over 70%, and in particular those for M-83 (a derivative of mitomycin C), nimustine hydrochloride and doxorubicin exceeded 80% by equations with 3-4 parameters. Consequently, the estimated value for each line of effectiveness derived from the equations for these 8 drugs showed remarkable coincidences with the actual values for the inhibition rates of the corresponding drugs.

Early diagnosis of spontaneous bacterial peritonitis: values of ascitic fluid variables.

In a search for clinical and laboratory factors that would aid in early diagnosis of spontaneous bacterial peritonitis, we identified two groups of patients with chronic liver disease and ascites: 1) 38 patients with 40 episodes of spontaneous bacterial peritonitis, and 2) 39 randomly selected patients with 40 sterile paracenteses who were matched for severity of liver dysfunction as a reference group. A variety of clinical and laboratory features were examined. The absolute lymphocyte count in peripheral blood was lower for the spontaneous bacterial peritonitis group (mean = 703/mm3 vs. 1,212/mm3, p less than 0.005). Four ascitic fluid variables, i.e., a white blood cell count of greater than or equal to 300/mm3, a polymorphonuclear leukocyte count of greater than or equal to 240/mm3, an ascitic fluid/serum LDH ratio of greater than or equal to 0.4, or an ascitic fluid/serum glucose ratio of less than or equal to 1.0, could separate the spontaneous bacterial peritonitis and reference groups with both sensitivity and specificity of greater than 70%. Although ascitic fluid total leucocyte and polymorphonuclear leucocyte counts are appropriate indicators for the early diagnosis of spontaneous bacterial peritonitis, the possibility of their false positivity should be warranted. The use of multiple tests including ascitic fluid/serum LDH and glucose ratios has better positive predictive value than a single test alone.

Evaluation of Serum Creatine Kinase and Lactate Dehydrogenase in Experimental Myocardial Infarction, Atriotomies, and Thoracotomies

Myocardial infarction causes elevation of the serum myocardial-associated isoenzyme of creatine kinase (CK-MB) and a serum isoenzyme of lactate dehydrogenase (LDH 1). Since atrial myocardium has as much CK-MB as ventricular myocardium, surgical manipulation of the atrium could cause elevation of serum CK-MB in the postoperative period. The distribution of LDH isoenzymes is different between atrial and ventricular myocardium. Hence, surgical procedures on the atrium could, theoretically, cause different changes in serum LDH isoenzymes than those seen after acute myocardial infarction. This study was conducted to ascertain whether surgical manipulation of the atrium could cause changes in these two serum enzyme systems that might be confused with those seen after acute myocardial infarction. Right thoracotomies were performed on 20 dogs. Each dog then was assigned randomly to one of four groups: thoracotomy (control), placement of atrial pursestring sutures, atriotomy, or acute perioperative myocardial infarction. Serum total and isoenzyme distributions of CK and LDH were measured for 48 hours in all animals. The results suggest that significant elevations of serum CK-MB occurred even after small atriotomies. Confirmation of a ventricular myocardial origin of postoperative serum CK-MB bands was obtained by analysis of serum LDH isoenzymes in that the ratio of LDH 1 to LDH 2 and the absolute value of serum LDH 1 became elevated only after acute perioperative myocardial infarction and not after atriotomy.

Metabolic enzyme response in the pressure-overloaded heart of weanling and adult rats.

Weanling and adult rats were subjected to left ventricular pressure overload induced by abdominal aortic constriction. At 5 days or 5 weeks postsurgery, the left ventricle (LV) was dissected, weighed, and metabolic marker enzyme activities (mumole/g/min) of tissue homogenates were measured. Enzymes representing glycolytic (phosphofructokinase (PFK] and mitochondrial (citrate synthase (CS) and malate dehydrogenase (MDH] metabolisms were evaluated. Five days of pressure overload had detectable, but statistically nonsignificant effects on left ventricles of both weanling and adult rats. Sustained pressure overload (5 weeks) increased LV weight by 52 and 39% in weanling and adult rats, respectively. PFK activity was 24 +/- 1 (mean +/- SE) in control weanlings and was unaltered in any of the other groups. LDH isoenzyme composition was estimated by substrate inhibition (ratio 0.33/10 mM pyruvate). With normal heart development, the LDH ratio increased from 1.89 +/- 0.06 to 2.03 +/- 0.08. Pressure overload had no influence on the adult LDH ratio. Developmental LDH responses were not observed in weanling LV after 5 weeks of aortic constriction (1.74 +/- 0.06). The product of CS activity and LV weight was used to estimate mitochondrial mass in the ventricle. Mitochondria accumulated at a rate of about 5% increase per day over the intervening 5-week period of normal heart growth. Pressure overload for 5 weeks in weanling rats elicited net accumulation of mitochondria at a rate of about 9% increase per day. Mitochondrial accumulation in the adapting adult rat heart amounted to less than 1% increase per day. The results indicate that qualitative and quantitative differences exist between young and adult animals in their heart enzyme adaptive responses to pressure overloading. Divergent metabolic adaptations may contribute to heart functional differences in the enlarged heart of weanlings and adults.