Lactate dehydrogenase isoenzymes

LDHA: The Obstacle to T cell responses against tumor

Immunotherapy has become a successful therapeutic strategy in certain solid tumors and hematological malignancies. However, this efficacy of immunotherapy is impeded by limited success rates. Cellular metabolic reprogramming determines the functionality and viability in both cancer cells and immune cells. Extensive research has unraveled that the limited success of immunotherapy is related to immune evasive metabolic reprogramming in tumor cells and immune cells. As an enzyme that catalyzes the final step of glycolysis, lactate dehydrogenase A (LDHA) has become a major focus of research. Here, we have addressed the structure, localization, and biological features of LDHA. Furthermore, we have discussed the various aspects of epigenetic regulation of LDHA expression, such as histone modification, DNA methylation, N6-methyladenosine (m6A) RNA methylation, and transcriptional control by noncoding RNA. With a focus on the extrinsic (tumor cells) and intrinsic (T cells) functions of LDHA in T-cell responses against tumors, in this article, we have reviewed the current status of LDHA inhibitors and their combination with T cell-mediated immunotherapies and postulated different strategies for future therapeutic regimens.

Serum Lactate Dehydrogenase Is a Sensitive Predictor of Systemic Complications of Acute Pancreatitis

BACKGROUND

Acute pancreatitis (AP) is a common and potentially life-threatening inflammatory disease that can cause various complications, including systemic inflammatory response syndrome (SIRS), pleural effusion, ascitic fluid, myocardial infarction, and acute kidney injury (AKI). However, there is still a lack of rapid and effective indicators to assess the disease. The aim of this study was to investigate the associations of high serum lactate dehydrogenase (LDH) levels with AP severity and systemic complications.

METHODS

AP patients treated from July 2014 to December 2020 were retrospectively enrolled. They were divided into elevated (n = 93) and normal (n = 143) LDH groups. Their demographic data, clinical data, hospital duration, and hospital expenses were analyzed. Linear and binary logistic regression analyses were used to determine whether elevated LDH is a risk factor for AP severity and complications after adjusting for confounders.

RESULTS

There were significant differences in AP severity scores (Ranson, MODS, BISAP, APACHE II, and CTSI), hospital duration, hospital expenses, and the incidences of complications (SIRS, pleural effusion, ascitic fluid, myocardial infarction, and AKI) between the elevated and normal LDH groups. After adjusting for confounders, elevated LDH was associated with AP severity scores and hospital duration and expenses (based on linear regression analyses) and was a risk factor for the occurrence of AP complications and interventions, that is, diuretic and vasoactive agent use (based on binary logistic regression analyses).

CONCLUSIONS

Elevated LDH is associated with high AP severity scores and high incidences of complications (SIRS, pleural effusion, ascitic fluid, myocardial infarction, and AKI).

Hemolytic markers following the transfusion of uncrossmatched, cold-stored, low-titer, group O+ whole blood in civilian trauma patients

BACKGROUND

Low-titer group O whole blood (LTOWB) is increasingly being used in the civilian trauma setting, although there is a risk of hemolysis. This study evaluated the impact on hemolytic markers following the transfusion of 4 or more units of uncrossmatched LTOWB.

METHODS

Civilian adult trauma patients who received four or more units of leukoreduced group O+, low-titer (<50 anti-A and anti-B), platelet-replete uncrossmatched whole blood during their initial resuscitation and who survived for more than 24 hours after the transfusion were included in this retrospective study. Lactate dehydrogenase (LDH), total bilirubin, haptoglobin, potassium, and creatinine were evaluated on the day of LTOWB transfusion (Day 0) and the next 3 days. Blood product administration over the first 24 hours of admission was recorded.

RESULTS

There were 54 non-group O and 23 group O recipients of four or more LTOWB units. The median (interquartile range [IQR]) number of transfused LTOWB units was 4 (4-5) and 4 (4-4), respectively, the maximum number in both groups was eight. The non-group O patients received a median (IQR) volume of 1470 mL (1368-2052) of ABO-incompatible plasma. Comparing the non-group O to the group O recipients, there were no significant differences in the haptoglobin, LDH, total bilirubin, potassium, or creatinine concentrations at any of the time points. There were no reported transfusion reactions.

CONCLUSION

Receiving at least four LTOWB units was not associated with biochemical or clinical evidence of hemolysis.

LDH isoenzyme 5 is an index of early onset muscle soreness during prolonged running

BACKGROUND

Muscle soreness is also induced during prolonged running such as a full marathon, and muscle soreness and increased damage markers are detected immediately after such a running. We named this muscle soreness, early onset muscle soreness (EOMS). Additionally, lactate dehydrogenase (LDH) level which has some isoenzyme is increased immediately after prolonged exercise. However, it is unclear that EOMS is related to muscle damage markers on prolonged running. This study aimed to determine at which point EOMS, and muscle damage markers are related to EOMS during prolonged running.

METHODS

We studied 11 male subjects who habitually perform aerobic exercise. They ran 30 km at 90% of ventilatory threshold intensity. Every 10 km, we estimated perceived muscle soreness, and sampled blood to measure muscle and liver damage, inflammation, and oxidative stress (d-ROM and BAP) markers.

RESULTS

Muscle soreness score lower limbs were significantly appeared at 20 km compared to that at 0 km. Serum lactate dehydrogenase (LDH) level increased at 30 km compared to that at 0 km. LDH isoenzymes 3, 4, and 5, and neutrophils significantly increased at 30 km compared to those at 0 km. Serum LDH isoenzyme 5 and change in aspartate aminotransferase significantly increased at 20 km. In addition, there was a significant correlation between the thigh NRS and amount of serum LDH isoenzyme 5 from 0 km to 20 km. d-ROM and BAP increased at 10 km compared to those at 0 km.

CONCLUSIONS

EOMS started to occur at 20 km during a 30 km running task. Our data suggest that LDH isoenzyme 5 is a marker of occurrence in EOMS during prolonged running.

Relationship between early-onset muscle soreness and indirect muscle damage markers and their dynamics after a full marathon

Background/Objective

Muscle soreness and damage occurs after completing a full marathon. Here we refer to muscle soreness induced by prolonged running as early-onset muscle soreness (EOMS) because muscle soreness and damage markers induced after prolonged running are different from delayed-onset muscle soreness (DOMS) and muscle damage markers induced after eccentric contraction, such as resistance exercise. The dynamics and relationship between muscle damage markers and EOMS are unclear; therefore, in this study, we aimed to elucidate the relationship between EOMS and indirect muscle damage markers, and their dynamics after a full marathon.

Methods

The following measurements were performed in 19 subjects who completed a full marathon: perceived muscle soreness (using a numeric rating scale), thigh circumference (CIR), hip joint range of motion (ROM), jump height (JH) and muscle damage marker activities in the blood (CK, AST, LDH, ALD) before (Pre), after (Post) and every day for 4 days after a full marathon (D1−4).

Results

EOMS was induced, as determined by the numeric rating scale score peaking immediately after a full marathon. ROM and JH significantly decreased and all muscle damage markers significantly increased after a full marathon. Serum CK and AST peaked at D1. Serum LDH and ALD peaked at Post and D3. Each marker showed different dynamics. CIR significantly decreased after a full marathon.

Conclusion

Muscle soreness peaked and muscle damage markers in the blood showed different dynamics after a full marathon. In other words, this is different from DOMS.

A more accurate method to interpret lactate dehydrogenase (LDH) isoenzymes' results in patients with uterine masses

OBJECTIVE

Since there are no approved reliable biomarkers for detecting preoperatively uterine sarcoma, lactate dehydrogenase (LDH) isoenzymes are usually required. We first evaluated the role of LDH isoenzymes in detecting uterine sarcoma risk, and then we tried to introduce a model to easily interpret the biochemical results.

METHODS

We retrospectively retrieved records of patients who underwent surgical treatment for uterine masses from 2004 to 2016, and we compared data of 2211 patients with a definitive surgical diagnosis of uterine fibroids and 43 with uterine sarcomas. Quantitative relationships between serum LDH isoenzymes levels, as different single markers or in multiple assays, and the final diagnosis were investigated.

RESULTS

LDH isoenzymes levels significantly differed between patients with benign uterine masses or sarcomas. LDH3 isoenzyme exhibited better predictive performances than the other four isoforms. Combining LDH3 with LDH1 isoenzymes into an inverse algebraic relationship, named Uterine mass Magna Graecia (U.M.G.) risk index, the accuracy of markers in discriminating between benign and suspicious malignant uterine masses was significantly enhanced, sensitivity at 100% and specificity at 99.6%, with nine false positive over 2211 benignant cases and no false negative over 43 sarcomas.

CONCLUSIONS

This retrospective analysis suggests to consider U.M.G. risk index as an inexpensive and accurate prognostic index that, once validated in a prospective study, may help clinicians in discriminating between benignant and suspicious malignant uterine masses.

Hyperfibrinolysis in severe isolated traumatic brain injury may occur without tissue hypoperfusion: a retrospective observational multicentre study

BACKGROUND

Hyperfibrinolysis is a critical complication in severe trauma. Hyperfibrinolysis is traditionally diagnosed via elevated D-dimer or fibrin/fibrinogen degradation product levels, and recently, using thromboelastometry. Although hyperfibrinolysis is observed in patients with severe isolated traumatic brain injury (TBI) on arrival at the emergency department (ED), it is unclear which factors induce hyperfibrinolysis. The present study aimed to investigate the factors associated with hyperfibrinolysis in patients with isolated severe TBI.

METHODS

We conducted a multicentre retrospective review of data for adult trauma patients with an injury severity score ≥ 16, and selected patients with isolated TBI (TBI group) and extra-cranial trauma (non-TBI group). The TBI group included patients with an abbreviated injury score (AIS) for the head ≥ 4 and an extra-cranial AIS < 2. The non-TBI group included patients with an extra-cranial AIS ≥ 3 and head AIS < 2. Hyperfibrinolysis was defined as a D-dimer level ≥ 38 mg/L on arrival at the ED. We evaluated the relationships between hyperfibrinolysis and injury severity/tissue injury/tissue perfusion in TBI patients by comparing them with non-TBI patients.

RESULTS

We enrolled 111 patients in the TBI group and 126 in the non-TBI group. In both groups, patients with hyperfibrinolysis had more severe injuries and received transfusion more frequently than patients without hyperfibrinolysis. Tissue injury, evaluated on the basis of lactate dehydrogenase and creatine kinase levels, was associated with hyperfibrinolysis in both groups. Among patients with TBI, the mortality rate was higher in those with hyperfibrinolysis than in those without hyperfibrinolysis. Tissue hypoperfusion, evaluated on the basis of lactate level, was associated with hyperfibrinolysis in only the non-TBI group. Although the increase in lactate level was correlated with the deterioration of coagulofibrinolytic variables (prolonged prothrombin time and activated partial thromboplastin time, decreased fibrinogen levels, and increased D-dimer levels) in the non-TBI group, no such correlation was observed in the TBI group.

CONCLUSIONS

Hyperfibrinolysis is associated with tissue injury and trauma severity in TBI and non-TBI patients. However, tissue hypoperfusion is associated with hyperfibrinolysis in non-TBI patients, but not in TBI patients. Tissue hypoperfusion may not be a prerequisite for the occurrence of hyperfibrinolysis in patients with isolated TBI.

Prognostic value of preoperative serum lactate dehydrogenase in thymic carcinoma

BACKGROUND

The prognostic value of serum lactate dehydrogenase (LDH) has been demonstrated in various solid tumors. We attempted to determine whether serum LDH was predictive of survival in thymic carcinoma after surgical resection.

METHODS

Ninety-five patients with thymic carcinoma treated in our hospital between January 2005 and December 2015 were retrospectively enrolled. Serum LDH was measured before surgery and categorized as low or high relative to the upper limit of normal (ULN) (225 U/L). The relationships of serum LDH level and other clinical variables with survival were estimated by Cox regression and Kaplan-Meier survival analysis.

RESULTS

Serum LDH levels were found to be significantly associated with overall survival (OS) and progression-free survival (PFS) of these patients. The 1-, 3-, and 5-year PFS were 76%, 51%, and 38%, and the 1-, 3- and 5-year OS were 97%, 75%, and 46%, respectively. Univariate analysis found that high serum LDH (>225 U/L) was associated with both lower OS [hazard ratio (HR) =2.710; 95% confidence interval (CI): 1.363-1.5.391; P=0.004] and PFS (HR =3.365; 95% CI: 1.776-6.374; P<0.001). Multivariate analysis found that high serum LDH was associated with lower PFS (HR =2.122; 95% CI: 1.056-4.267; P=0.035). Moreover, high LDH was significantly associated with advanced Masaoka stage (P=0.001).

CONCLUSIONS

High serum LDH (>225 U/L) was an independent predictor of decreased PFS in thymic carcinoma patients. It was also significantly associated with reduced OS, but was not an independent predictor of death in those patients.

Serum lactate dehydrogenase and survival following cancer diagnosis

BACKGROUND

There is evidence that high level of serum lactate dehydrogenase (LDH) is associated with poorer overall survival in several malignancies, but its link to cancer-specific survival is unclear.

METHODS

A total of 7895 individuals diagnosed with cancer between 1986 and 1999 were selected for this study. Multivariable Cox proportional hazards regression was used to assess overall and cancer-specific death by the z-score and clinical categories of serum LDH prospectively collected within 3 years before diagnosis. Site-specific analysis was performed for major cancers. Analysis was repeated by different lag times between LDH measurements and diagnosis.

RESULTS

At the end of follow-up, 5799 participants were deceased. Hazard ratios (HRs) and 95% confidence intervals (CIs) for overall and cancer-specific death in the multivariable model were 1.43 (1.31-1.56) and 1.46 (1.32-1.61), respectively, for high compared with low prediagnostic LDH. Site-specific analysis showed high LDH to correlate with an increased risk of death from prostate, pulmonary, colorectal, gastro-oesophageal, gynaecological and haematological cancers. Serum LDH assessed within intervals closer to diagnosis was more strongly associated with overall and cancer-specific death.

CONCLUSIONS

Our findings demonstrated an inverse association of baseline serum LDH with cancer-specific survival, corroborating its role in cancer progression.

Inhibition of the Warburg effect with a natural compound reveals a novel measurement for determining the metastatic potential of breast cancers

Metabolism is an important differentiating feature of cancer cells. Lactate dehydrogenases (LDH) A/B are metabolically important proteins and are involved in the critical step of inter-conversion of lactate to pyruvate. Panepoxydone (PP), a natural NF-kB inhibitor, significantly reduces the oxygen consumption and lactate production of MCF-7 and triple negative (MDA-MB-231, MDA-MB-468 and MDA-MB-453) breast cancer cells. We further observed that PP inhibited mitochondrial membrane potential and the ATP synthesis using flow cytometry. PP also up-regulated LDH-B and down-regulated LDH-A expression levels in all breast cancer cells to similar levels observed in HMEC cells. Over-expression of LDH-B in cancer cell lines leads to enhanced apoptosis, mitochondrial damage, and reduced cell migration. Analyzing the patient data set GDS4069 available on the GEO website, we observed 100% of non TNBC and 60% of TNBC patients had less LDH-B expression than LDH-A expression levels. Herein we report a new term called Glycolytic index, a novel method to calculate utilization of oxidative phosphorylation in breast cancer cells through measuring the ratio of the LDH-B to LDH-A. Furthermore, inhibitors of NF-kB could serve as a therapeutic agent for targeting metabolism and for the treatment of triple negative breast cancer.

Sources of variation analysis and derivation of reference intervals for ALP, LDH, and amylase isozymes using sera from the Asian multicenter study on reference values

BACKGROUND

Sources of variation (SV) of ALP, LDH, and amylase isozymes were explored.

METHODS

We analyzed 3511 sera from well-defined healthy individuals recruited during the 2009 Asian project for derivation of common reference intervals (RIs). Up-to-date electrophoresis auto-analyzer and reagents were employed for high resolution and reproducibility. SVs including sex, age, body mass index (BMI), ABO blood groups, and levels of drinking, smoking, and exercise were analyzed by multiple regression analysis. RIs were determined by parametric methods after refining healthy individuals by use of latent reference values exclusion method.

RESULTS

Age-related changes in ALP2-3 were different in females: ALP2, linear increase from 20-64y; ALP3, lowering until 45 y and rising steeply thereafter. ALP2 increased with BMI especially in females. ALP5 was barely detectable except in blood-types O and B. Age-related increases in LDH1-LDH3 were noted in females, whereas BMI-related increases were found only for LDH2-LDH5 in both sexes. Pancreatic amylase showed age-related increase in females and was slightly higher in blood-type O. RIs for absolute and relative activities of each isozyme were derived in consideration of sex and age.

CONCLUSIONS

Investigation of these isozymes revealed various age-, BMI-, and blood-type-related changes that are all relevant in clinical interpretation of enzyme test results.

Elevated serum lactate dehydrogenase isoenzymes and aspartate transaminase distinguish Albers-Schönberg disease (Chloride Channel 7 Deficiency Osteopetrosis) among the sclerosing bone disorders

Osteopetrosis (OPT) refers to the consequences of generalized failure of skeletal resorption during growth. Most cases are explained by loss-of-function mutation within the genes that encode either chloride channel 7 (CLCN7) or a vacuolar proton pump subunit (TCIRG1), each compromising acid secretion by osteoclasts. Patients suffer fractures and sometimes cranial nerve entrapment and insufficient medullary space for hematopoiesis. In 1996, we reported that a high serum level of the brain isoenzyme of creatine kinase (BB-CK), the CK of osteoclasts, characterizes OPT dueamong the sclerosing bone disorders (J Clin Endocrinol Metab. 1996;11:1438). Now, we show that elevation in serum of multiple lactate dehydrogenase (LDH) isoenzymes with aspartate transaminase (AST) distinguishes autosomal dominant OPT due to loss-of-function mutation in CLCN7 [Albers-Schönberg disease (A-SD)] among these conditions. Serum total LDH and AST levels as high as 3× and 2×, respectively, the upper limits of normal for age-appropriate controls, were persistent and essentially concordant in A-SD. Serum LDH was elevated in 7 of 9 children and in the 2 adults studied with A-SD. LDH isoenzyme quantitation showed excesses of LDH-2, -3, and -4. Neither total LDH nor AST increases were found in other forms of OPT, including bisphosphonate-induced OPT, or in 41 children and 6 adults representing 20 additional sclerosing bone disorders. Serum TRACP-5b and BB-CK also were markedly elevated in A-SD. Hence, high serum levels of several enzymes characterize A-SD. Elevated serum LDH isoenzymes and AST indicate a disturbance (of uncertain clinical significance) within multiple extraosseous tissues when there is CLCN7 deficiency.

Total tissue lactate dehydrogenase activity in endometrial carcinoma

Lactate dehydrogenase (LDH) is essential for continuous glycolysis necessary for accelerated tumor growth. The aim of this study was to reconsider if assay of total tissue activity of this enzyme could be useful as marker for endometrial carcinoma (EC). Activity of LDH was measured spectrophotometrically in homogenate supernatants of uterine tissue samples of 40 patients (10 normal endometria, 27 normal myometria, and 33 EC), including 30 matched pairs. Data obtained were analyzed in relation to clinical and histopathologic findings and compared with our previously published results on the tissue levels of the same enzyme in ovarian cancer and on the proteolytic activity of dipeptidyl peptidase III (DPP III) in EC (suggested biochemical indicator of this malignancy). Significantly increased (1.8-3.0 times; P < 1 x 10(-4)) LDH activity was observed in EC samples if compared with normal uterine tissues. This rise was not related to the clinicopathologic findings, however. In contrast to previous results on LDH in ovarian carcinomas, a significant rise in LDH activity was found already in grade 1 EC. Using the cutoff value of 1.06 U/mg, diagnostic sensitivity of 82%, specificity of 100%, and accuracy of 91% for total tissue LDH assay have been calculated. A correlation of tissue's LDH and DPP III activities was found, and their combined assay for EC showed increased diagnostic sensitivity (94%) and accuracy (96%).

Laboratory markers and germ cell tumors

The International Germ Cell Consensus Classification (IGCCC) of testicular germ cell tumors (TGCT) in 1997 included three serum tumor markers, serum lactate dehydrogenase catalytic concentration (S-LD), serum alpha fetoprotein concentration (S-AFP), and serum human chorionic gonadotropin concentration (S-hCG). The recommendation should be implemented for all patients with TGCT and is also useful for patients with ovarian and extragonadal germ cell tumors. A fourth serum tumor marker for TGCT, S-LD isoenzyme 1 (S-LD-1), is also relevant for TGCT. Patients with seminoma have a raised S-LD-1 more often than a raised S-AFP and S-hCG, whereas patients with nonseminoma have a raised S-AFP more often than a raised S-LD-1 and S-hCG. A new model combining IGCCC and S-LD-1 predicts survival better than previous staging systems. LD-1 is related to a characteristic chromosomal abnormality in all types of TGCT, a high copy number of chromosome 12p. In contrast, AFP and hCG are found mainly in nonseminomatous germ cell tumors and they related to the histologic differentiation of the tumors. The different biologic background for the serum tumor markers may contribute to the difference in their clinical behavior.

Relative mRNA expression of the lactate dehydrogenase A and B subunits as determined by simultaneous amplification and single strand conformation polymorphism. Relation with subunit enzyme activity

To explore if it is correlated in human tumor cells that the expression of LDH homologous gene and LDH isoenzymes, we used RT-PCR-SSCP technique to measure the relative expression of genes with homologous sequences. The combination of PCR using common primers designed in the highly conserved regions and single-strand conformation polymorphism analysis of the products is used for quantitative determination of the proportions of LDH-A mRNA in human cancer cell lines. The proportion is compared with that of the activities of isoenzymes. The results indicated that the enzyme activity of LDH-A was consistent with mRNA levels in the human tumor cell. The present procedure using a single pair of primers for two fragments can overcome disadvantages in quantitative analysis using multiplex PCR. Template concentrations and PCR cycles did not affect the proportions of LDH-A and LDH-B in the product.

Electrophoretic Variant of a Lactate Dehydrogenase Isoenzyme and Selective Promoter Methylation of the LDHA Gene in a Human Retinoblastoma Cell Line

Background: Lactate dehydrogenase (LD), a tetrameric product of the genes LDHA and LDHB, may be increased in sera of cancer patients. A variant isoenzyme with electrophoretic mobility between LD2 and LD3 (LD2ex) has been described in patients, but its molecular nature is largely unknown.

Methods: A newly established retinoblastoma cell line, NCC-RbC-51 (R51), showed an isoenzyme pattern with only two bands, LD1 and LD2ex. We investigated the isoenzymes by Northern blot, Western blot, and methylation analysis and PCR.

Results: Northern blot analysis revealed that R51 cells expressed no wild-type/somatic LDHA mRNA, but did express a small amount of LDHA-related mRNA with a slightly higher molecular mass. Western blot analysis confirmed the anti-LDHA-reactive protein with a 3-kDa higher molecular mass. Treatment of R51 cells with the demethylating agent 5-aza-2′-deoxycytidine restored the expression of the LD2, -3, -4, and -5 isoenzymes. PCR analysis of sodium bisulfite-treated genomic DNA revealed that the CpG island in the promoter region around exon a of the LDHA gene was completely methylated. Reverse transcription-PCR analysis and direct sequencing revealed that R51 cells expressed a RNA with the sequence of the human homolog of a murine testis-specific variant that has exon 0 as the 5′ noncoding sequence. LDHB was expressed normally in R51 cells.

Conclusions: The somatic LDHA in R51 cells is transcriptionally silenced by promoter hypermethylation around exon a, leaving only LDHB to be expressed normally and a testis-specific variant transcript of LDHA containing exon 0. LD2ex possibly results from tetramerization of three wild-type LDHB molecules and one variant LDHA product.

A systematic review of lactate dehydrogenase isoenzyme 1 and germ cell tumors

OBJECTIVES

To evaluate lactate dehydrogenase isoenzyme 1 (LD-1) as a tumor marker of germ cell tumors.

METHODS

A literature search included a CancerLit and Medline computer search of articles regarding germ cell tumors and LD-1 published between 1963 to 99 and a manual search of reference lists, theses, and textbooks. Forty articles, letters to the editor, and abstracts on testicular germ cell tumors and 10 articles on ovarian germ cell tumors fulfilled inclusion criteria.

RESULTS

Of 696 patients with testicular germ cell tumors, 423 (61%) had a raised serum LD-1 catalytic concentration (S-LD-1). Patients with seminoma have a raised S-LD-1 more often (63%) than those with nonseminoma (60%). S-LD-1 was raised less often in patients with stage I (48%) than in those with stage II (50%) and stage III (67%). S-LD-1, serum alpha fetoprotein concentration (S-AFP), and serum human chorionic gonadotropin concentration (S-hCG) were discordant. S-LD-1 predicted outcome in four studies: one study regarding relapse in patients with nonseminomatous testicular germ cell tumors stage I, and three studies regarding survival of patients with metastatic testicular germ cell tumors. In two of three studies, S-LD-1 was a better prognostic predictor for patients with metastatic testicular germ cell tumors than S-LD. Of 40 patients with ovarian germ cell tumors, thirty-five (88%) had a raised S-LD-1.

CONCLUSIONS

S-LD-1 is a useful serum tumor marker of testicular germ cell tumors. For patients with ovarian germ cell tumors, S-LD-1 was raised more often than for patients with testicular germ cell tumors. Further studies are required for a general recommendation regarding the use of S-LD-1 for germ cell tumors.

Analytical quality specifications for serum lactate dehydrogenase isoenzyme 1 based on clinical goals

The aim of the study was to deduce analytical quality specifications for the determination of catalytic concentration of serum lactate dehydrogenase isoenzyme 1 (S-LD-1) according to clinical goals (the clinical utility model). We defined clinical goals for false positive and false negative S-LD-1 measurements in the monitoring of patients with testicular germ cell tumors (TGCT), clinical stage I, on a surveillance only program. The absolute S-LD-1 catalytic concentrations were routinely corrected for contamination from preanalytical hemolysis. A reference group of 37 men had a near In-Gaussian distribution for the absolute S-LD-1 catalytic concentration. The geometric mean was 76 U/l and an S-LD-1 >128 U/l (99.72 percentile, the decision limit) indicated a high risk of a relapse of TGCT. We have previously shown that an S-LD-1 >160 U/l (treatment limit) was associated with a suboptimal outcome from the treatment of metastatic TGCT. The maximum allowable analytical positive bias was 5 U/l, and the maximum allowable analytical negative bias was -32 U/l. The maximum allowable analytical coefficient of variation, CV(A), was 11% (approximately 14 U/l) at a bias = -5 U/l. For S-LD-1 measurements not corrected for hemolysis, the decision limit was 145 U/l, the maximum allowable negative bias -19 U/l, and CV(A) 8%(approximately 12 U/l). A routine correction for hemolysis had a large impact on the analytical quality specifications.

Quantification of relative expression of genes with homologous sequences using fluorescence-based single-strand conformation polymorphism analysis--application to lactate dehydrogenase and cyclooxygenase isozymes

The combination of reverse transcribed-PCR and fluorescence-based single strand conformation polymorphism analysis has been proposed for the quantitative determination of ratio of mRNA molecules with homologous sequences. We applied this procedure to lactate dehydrogenase subunits M and H, and cyclooxygenase 1 and 2. We designed fluorescence labeled common PCR primers in the sequences highly homologous between two subunit and isozyme cDNAs, and performed reverse transcribed-PCR and fluorescence-based single strand conformation polymorphism analysis. PCR efficiency was almost the same for the different target sequences, so analysis of mixtures of known amounts of lactate dehydrogenase M and H revealed linear and precise proportions of lactate dehydrogenase M mRNA. It was shown that template concentrations and number of PCR cycles did not affect the determination of proportions of lactate dehydrogenase M to total lactate dehydrogenase. The procedure was applicable to a determination of cyclooxygenase-2 proportion; furthermore, the present procedure could be easily applied to investigation of expression levels of genes encoding mRNAs with homologous sequences.

Amperometric immunosensor for lactate dehydrogenase LD-1

An amperometric immunosensor for the detection of the lactate dehydrogenase isoenzyme LD-1 has been developed. Polyclonal antibodies for LD-1 have been covalently immobilised onto a preactivated Immunodyne ABC membrane, reacted with standard LD-1 solutions and placed onto a platinum working electrode polarised at +600 mV vs. Ag/AgCl. Lactate dehydrogenase activity has been measured by detection of the oxidation of NADH at the electrode surface. A calibration curve for LDH in the 0.005-0.12 U range has been obtained with a repeatability of 3% and a reproducibility of 10%. The probe exhibited good selectivity (response of LD-2 was 18% of LD-1) which was further improved using thermal treatment of the membranes. Measurement of LD-1 content in human control serum with the developed procedure gave a LD-1 concentration in the reported assigned range.

The sum of vectors method (SV) applied to lactate dehydrogenase isoenzymes and creatine kinase isoforms

The method of vectorisation and of summation of biochemical quantity vectors (SV), complemented by models, is suggested for description of data involving three or more quantities. By the SV method, the data of sample quantities are transformed into a vector which preserves sample quantity information. Examples are presented to demonstrate patient monitoring after acute myocardial infarction (AMI) by the SV method and by variously ordered sets of LD and CK patterns. Furthermore, compared with MM3/MM1 isoform ratios, the set of CK quantities (MM3, MM2, MM1) together with the basic model SV3 is able to monitor the processes of CK isoform changes and to indicate unusual quantity values compared with reference values. Similarly, the translation model SV3 with the set of MM3, MB2, MB1 quantities and dSV3 vectors, obtained by subtraction of the control vector from all resultant SV3 vectors, monitors individual deviations from the control values. In the case of inadequate SV ¿c¿ values, the SV3 translation model indicates a possibility of excess MM3 release from non-cardiac tissues. The SV method, with basic model SV5 and ordered set of LD quantities (1-5) enables AMI to be proved in the group of patients whose LD1/2 < 0.76 and activity of LD5 > 10%. In general, apart from isoenzyme data processing, the SV method can also be applied for processing other data object quantities.

Methods for the separation of lactate dehydrogenases and clinical significance of the enzyme

Lactate dehydrogenase (LDH), an ubiquitous enzyme among vertebrates, invertebrates, plants and microbes was discovered in the early period of enzymology. The enzyme has been dissolved in several distinguishable molecular forms. In mammals, three types of subunits encoded by the genes Ldh-A, Ldh-B and Ldh-C give rise to a selected number of tetrameric isoenzymes. LDH-A4, LDH-B4 and the mixed hybrid forms of the A- and B-subunits are present in many tissues but with certain distribution patterns. LDH-C4 is confined in mammals to testes and sperm. Numerous techniques have been employed to purify, characterize and separate the different forms of the enzyme. This report deals with the main protocols and procedures of purification of LDH and its isoenzymes including chromatographic and electrophoretic methods, partitioning in aqueous two-phase systems and precipitation approaches. In particular, affinity separation techniques based on natural and pseudo-biospecific ligands are described in detail. In addition, basic physico-chemical and kinetic properties of the enzyme from different sources are summarized in a second part, the clinical significance of the determination of LDH in diverse body fluids in respect to the total activity and the isoenzyme distribution in different organs is discussed.

Effect of constant and modulated electrical charges applied to the culture material on PGI2 and TXA2 secretion by endothelial cells

Electrical stimulation of an endothelial cell culture applied through the culture support biomaterial induced strong secretion of prostaglandin I2 (PGI2) and, to a lesser extent, thromboxane A2 (TXA2), which varied with time, the sign of the stationary electrical charge and the amplitude and frequency of a superimposed sine wave. In stationary conditions, the response is more rapid at positive electrical charges (+ some tens of microC cm-2) than at negative ones (-some tens of microC cm-2). In sine wave conditions, the ratio [PGI2]/[TXA2] is strongly increased and is maximum for an amplitude of 50 mV and a frequency of 1 Hz. These results suggest that the extracellular matrix is not only involved in cellular anchoring but also participates actively in secretion of thrombomodulatory substances, an effect apparently related to the piezoelectric properties of its components.

Purification and properties of lactate dehydrogenase from liver of Uromastix hardwickii

Lactate dehydrogenase isoenzyme-1 was purified from liver of Uromastix hardwickii using colchicine-Sepharose and heat-inactivation methods. The crude enzyme showed four isoenzymes by agarose gel electrophoresis (AGE). The purified enzyme showed a single band after native AGE and SDS-PAGE corresponding to a molecular weight of 34 kDa. The enzyme did not bind with DEAE-Sepharose at pH 7.2. The optimum pH for forward reaction was 7.5, while for reverse reaction, the maximum activity was at pH 9.5. The Km values for pyruvate, NADH, lactate and NAD+ were 0.105, 0.045, 9.0 and 0.011 mM, respectively. The pyruvate showed maximum activity at about 150 microM and then starts showing inhibition at higher concentration. Pre-heating of enzyme showed that it was stable at 80 degrees C for 30 min and at 100 degrees C it became inactive immediately. Oxalate, glutamate, Cu2+, Co2+, Mn2+, and Mg2+ have shown inhibitory effects both for forward- and reverse-reactions. From these properties, we suggest that LDH-1 from Uromastix liver may be quite different from that of other vertebrates.

Lactate dehydrogenase levels during MACOP-B chemotherapy for non-Hodgkin's lymphoma

Lactate dehydrogenase (LD) levels rose consistently during MACOP-B chemotherapy for intermediate and high-grade non-Hodgkin's lymphoma (NHL). Levels peaked at week nine and fell to normal within six weeks of completion of therapy. Isoenzyme patterns, studied prospectively in seven patients, showed a parallel rise in LD1 and LD2 suggesting a source other than tumour tissue for the rise in total LD. In the absence of evidence of myocardial or renal damage, haematopoietic tissue was the most likely source. With no evidence of haemolysis, normal serum levels of vitamin B12 and folate and normal red cell folate, dyserythropoiesis was considered to be the underlying mechanism. A rising mean corpuscular volume further reinforced this suggestion. Intensive use of methotrexate along with co-trimoxazole as prophylaxis against pneumoycystis carinii is considered the most likely cause of marrow dysfunction. Failure to recognise that rising LD levels during such therapy is treatment-related, rather than of tumour origin, may lead to inappropriate change or abandonment of therapy.

Effect of epidermal growth factor/transforming growth factor alpha on lactate production in porcine Sertoli cells: glucose transport and lactate dehydrogenase isozymes as potential sites of action

Germ cell development is dependent upon the delivery of essential nutriments such as lactate originating from Sertoli cells. Lactate production is under the systemic control but probably also under a local control exerted via certain growth factors. By using a model of porcine cultured Sertoli cells, we have characterized the action of epidermal growth factor (EGF) on lactate production and further delineated the potential biochemical mechanisms involved in the EGF action. EGF stimulated lactate production in a time and dose dependent manner with a half-maximal (ED50) and maximal effects, respectively with 3.8 (0.6 x 10(-9) M) and 22 ng/ml of EGF. Lactate formation involves several biochemical steps among which the glucose substrate uptake and transport system as well as the lactate dehydrogenase (LDH) activity appear to play key roles. We report here that EGF increased the uptake of glucose evaluated through that of 2-deoxy-D-glucose (2-DOG), a non-metabolizable glucose analog. Such an increase in glucose substrate uptake occurs both after a long term (48 h) and a short term treatment (ED50 = 6.4 ng/ml, 1.1 x 10(-9) M EGF). Moreover, EGF was also able to enhance the activity of the Sertoli cell LDH. The maximal effect of the growth factor on LDH activity was observed after a long term (24 h) treatment with an ED50 of 7 ng/ml (1.2 x 10(-9) M).(ABSTRACT TRUNCATED AT 250 WORDS)

C-reactive protein and lactate dehydrogenase isoenzymes in the assessment of the prognosis of acute pancreatitis

The value of serum C-reactive protein, lactate dehydrogenase isoenzymes and erythrocyte sedimentation rate in predicting the outcome of acute pancreatitis was evaluated for 57 episodes in 54 patients. Serum C-reactive protein levels on day 2, 4 and 7 after admission were significantly higher in 19 episodes of severe attacks than in 38 episodes of mild attacks (13.71 +/- 9.68, 9.00 +/- 7.54, 6.02 +/- 3.83 vs 4.78 +/- 3.91, 3.30 +/- 3.61, 1.43 +/- 2.08 mg/dL; P less than 0.0001, P less than 0.005, P less than 0.0001, respectively). The sensitivity, specificity and accuracy of predicting a severe attack were 94, 76 and 82% using C-reactive protein greater than or equal to 8 mg/dL on day 2; 67, 92 and 84% using C-reactive protein greater than or equal to 5 mg/dL on day 7; and 59, 76 and 70% using Ranson's criteria greater than or equal to 3. Increases in LDH-4 and LDH-5 isoenzymes were found in both groups, with LDH-4 being slightly higher in severe attacks than in mild attacks. There was no significant difference of erythrocyte sedimentation rate between both groups. When compared with Ranson's criteria, lactate dehydrogenase isoenzymes and erythrocyte sedimentation rate, C-reactive protein is more valuable in the early assessment of the severity of acute pancreatitis.

Dye-ligand affinity partitioning of lactate dehydrogenase isoenzymes

Aqueous two-phase systems consisting of dextran and polyethylene glycol (PEG) were used to study the partition behaviour of isoenzymes of lactate dehydrogenase (LDH; E.C. 1.1.1.27) from rabbit tissues in the presence and absence of a series of triazine dyes covalently coupled to PEG. The variations in the primary structures of LDH1(H4) and LDH5(M4) are reflected by significantly different partition coefficients. A class of dyes exhibiting defined structural elements is able to distinguish between both of these isoenzymes. This may be based on differences in the binding affinity to the catalytic site of the enzyme. The difference in the relative affinities of LDH1 and LDH5 to Procion Blue H-5R, as estimated by affinity partitioning, were corroborated by chromatographic experiments. Affinity partitioning in aqueous two-phase systems can be used to predict and to optimize conditions for the fast and simple chromatographic separation of isoenzymes.

Electrophoresis of serum isoenzymes and proteins following acute myocardial infarction

The clinical significance of the serum enzymes creatine kinase (CK, EC 2.7.3.2), lactate dehydrogenase (LD, EC 1.1.1.27) and aspartate aminotransferase (EC 2.6.1.1), and the isoenzymes CK 1-3 and LD 1-5, in acute myocardial infarction (AMI) is reviewed. Particular attention is given to electrophoretic analysis of the isoenzymes (and the CK isoforms/subforms) following AMI and thrombolytic therapy. Other protein markers for the monitoring of AMI, including myoglobin and muscle contractile proteins, are also discussed and the potential for the detection of new marker proteins using high-resolution two-dimensional electrophoretic methods is demonstrated. Whilst emphasis is placed upon electrophoretic methods the value of complementary immunoassays is acknowledged in order to maintain a balanced perspective.

Detection of macroenzymes in serum by high-performance gel permeation chromatography

A rapid high-performance gel permeation chromatographic method to confirm the presence of enzymes with abnormally high relative molecular masses (macroenzymes) in serum is described. The technique requires 200 microliters of serum, can be automated and has been implemented for the analysis of creatine kinase (CK), lactate dehydrogenase, amylase, and alkaline phosphatase (ALP) activities. Serum fractionation according to relative molecular mass is completed within 21 min, and 84-106% of enzyme activities are recovered in the eluted fractions. The elution patterns obtained make possible the differentiation of 40 samples containing at least 10 U/l immunoglobulin-enzyme complexes, aggregated mitochondrial CK or membrane fragments carrying ALP activity from 40 control samples without these high-mass enzyme forms.