Lactic dehydrogenase isoenzyme determination in the diagnosis of acute myocardial infarction

α-HBDH is a superior to LDH in predicting major adverse cardiovascular events in patients with acute aortic dissection

Objective

Acute aortic dissection (AAD) with a high mortality and postoperative complications remains presently no effective indicators to conjunctly predict the short-term mortality and the prognosis. This study aimed to investigate the predictive role of α-HBDH on in-hospital mortality and postoperative Major adverse cardiovascular events (MACE) in patients with AAD.

Methods

In this retrospective study, a total of 369 enrolled patients from 2015 to 2021 were divided into three groups (T1: low, T2: medium and T3: high) based on the tertiles of α-HBDH levels on admission. In terms of the preoperative, intraoperative and postoperative indicators among 3 groups, the relationship between α-HBDH and studying endpoints was determined by logistic regression models, along with the consolidation using Kaplan-Meier and restricted cubic spline (RCS) analysis for predicting the in-hospital death and MACE complications. Last, subgroup analysis further verified the predictive value of α-HBDH.

Results

Logistic regression analysis showed that α-HBDH was independently associated with in-hospital mortality of patients with AAD [OR(95CI): 4.771(1.043-21.832), P = 0.044] and MACE [OR(95CI): 9.869(2.148-45.349), P = 0.003]. Moreover, Kaplan-Meier analysis also showed an increased α-HBDH levels associated with poor survival within 30 days (log rank test, P < 0.01), especially in acute Stanford A dissection. RCS presented that 204 U/L was the optimal cut-off value of α-HBDH for in-hospital mortality and postoperative MACE, which facilitated clinical stratification of patients with AAD. Subgroup analysis confirmed a stable correlation between α-HBDH level and hospital mortality and MACE (P > 0.05).

Conclusions

α-HBDH is a predictor of the in-hospital mortality and postoperative MACE, guiding admission stratification of patients with AAD.

Associations between antibiotic exposure and abnormal cardiac enzyme profiles in older Chinese adults

Biomonitoring methods can be used to measure exposure to antibiotics in the general population; however, epidemiological data on the associations between urinary antibiotic levels and the cardiac profiles of enzymes lactate dehydrogenase, creatine kinase, and creatine kinase isoenzyme in older adults remain sparse. We investigated these associations in 990 individuals from the Cohort of Elderly Health and Environment Controllable Factors. Antibiotic residues in urine samples were analyzed using high-performance liquid chromatography-tandem mass spectrometry. Urinary levels of 34 antibiotics were measured. The participants' cardiac enzyme profiles were influenced by sex, age, marital status, education level, cohabitation status, physical activity, dietary structure, body mass index, depression presence and salt, sugar, and oil consumption (P < 0.05). Oxytetracycline, tetracycline, doxycycline, sulfaclozine, and, florfenicol concentrations were negatively associated with the risk of having an abnormal cardiac enzyme profile. Older adults exposed to higher concentrations of norfloxacin had a higher risk of LDH anomalies. After antibiotics were classified, we identified associations between exposure to chloramphenicols, sulfonamides, or veterinary antibiotics and a lower risk of having an abnormal cardiac enzyme profile. Obtaining an accurate epidemiological profile of antibiotic exposure is indispensable for the prevention and detection of cardiac enzyme profile abnormalities in older adults.

Prevalence of Cardiovascular Complications in Coronavirus Disease 2019 adult Patients: A Systematic Review and Meta-Analysis

Background

It has been found that the new coronavirus can affect various parts of the cardiovascular system. Cardiovascular complications caused by coronavirus disease 2019 (COVID-19) are often serious and can increase the mortality rate among infected patients. This study aimed to investigate the prevalence of cardiovascular complications in COVID-19 adult patients.

Methods

A systematic review and meta-analysis of observational studies published in English were conducted between December 2019 and February 2021. A complete search was performed in PubMed (PubMed Central and MEDLINE), Google Scholar, Cochrane Library, Science Direct, Ovid, Embase, Scopus, CINAHL, Web of Science, and WILEY, as well as BioRXiv, MedRXiv, and gray literature. A random effect model was used to examine the prevalence of cardiovascular complications among COVID-19 patients. The I2 test was used to measure heterogeneity across the included studies.

Results

A total of 74 studies involving 34,379 COVID-19 patients were included for meta-analysis. The mean age of the participants was 61.30±14.75 years. The overall pooled prevalence of cardiovascular complications was 23.45%. The most prevalent complications were acute myocardial injury (AMI) (19.38%, 95% CI=13.62-26.81, test for heterogeneity I2=97.5%, P<0.001), arrhythmia (11.16%, 95% CI=8.23-14.96, test for heterogeneity I2=91.5%, P<0.001), heart failure (HF) (7.56%, 95% CI=4.50-12.45, test for heterogeneity I2=96.3%, P<0.001), and cardiomyopathy (2.78%, 95% CI=0.34-9.68). The highest pooled prevalence of cardiac enzymes was lactate dehydrogenase (61.45%), troponin (23.10%), and creatine kinase-myocardial band or creatine kinase (14.52%).

Conclusion

The high prevalence of serious cardiovascular complications in COVID-19 patients (AMI, arrhythmia, and HF) necessitates increased awareness by healthcare administrators.

Association of greenness exposure with coronary artery stenosis and biomarkers of myocardial injury in patients with myocardial infarction

BACKGROUND

Greenness has been linked to cardiovascular health; however, limited evidence is available regarding its association with coronary artery stenosis and biomarkers of myocardial injury. We aimed to assess these associations and examine their modification and mediation effects in patients with myocardial infarction (MI).

METHODS

This study included 2030 patients with MI. The normalized difference vegetation index (NDVI) was used to characterize greenness exposure. We used a logistic regression model to explore the relationship between coronary artery stenosis and residential greenness, and applied linear regression models to assess the association of greenness with biomarkers of myocardial injury. The bootstrap method was used to explore whether potential variables mediated the associations. To further investigate the exposure-response curve describing these relationships, we developed restricted cubic spline models.

RESULT

Compared to the lowest quartile of NDVI, the odds ratio (OR) (95 % confidence interval [CI]) for severe stenosis (≥75 % stenosis) was 0.68 (95 % CI: 0.47 to 0.98) for the third quartile. Participants in the highest greenness exposure quartile had lower levels of cardiac troponin I (cTnI), creatine kinase (CK), and creatine kinase isoenzyme (CKMB) than those in the lowest quartile (β = -0.22, 95 % CI: -0.40 to -0.05; β = -0.13, 95 % CI: -0.22 to -0.04; β = -0.07, 95 % CI: -0.14 to -0.003). The association between residential greenness and myocardial injury biomarkers was stronger in men and older participants. Mediation analyses revealed that the effects of greenness on coronary stenosis, cTnI, CK, and CKMB were mediated by systolic blood pressure (SBP) and diastolic blood pressure (DBP).

CONCLUSION

Higher greenness exposure was associated with coronary artery stenosis and reduced levels of myocardial injury biomarkers, including cTnI, CK, and CKMB. These associations may be partially mediated by SBP and DBP levels.

An overview of prognostic value of neurologic and cardiac biomarkers in patients with COVID-19 sequelae

Many studies conducted after the pandemic period revealed that, while COVID-19 primarily injured the lungs, it also affects other organs in the form of cardiovascular complications, metabolic derangements, renal damage, and so on. Although we know that inflammatory cascades, complement activation, and pro-inflammatory cytokines are all involved in vasculitic processes that cause organ damage, we do not know the exact mechanism of complications such as acute respiratory distress syndrome (ARDS), cardiovascular ischemia, deep vein thrombosis, pulmonary thromboembolism, and brain injuries (embolism) that are frequently observed in COVID 19. The currently available biomarkers do not predict the severity of the aforementioned complications. As a result, more specific biomarkers such as serum calcium binding protein (S100B), glial fibrillary acid protein (GFAP), myelin basic protein (MBP), neuron-specific enolase (NSE), hs-TNI, (highly sensitive cardiac troponin) - HBDH, (Hydroxybutyrate Dehydrogenase), CK-MB (creatine kinase myocardial band), ST2 (suppression of tumorigenicity 2) are in need for early detection & improved clinical outcome.

Clinical, Biochemical, and Molecular Characterization of Two Families with Novel Mutations in the LDHA Gene (GSD XI)

Lactate dehydrogenase (LDH) catalyzes the reversible conversion of L-lactate to pyruvate. LDH-A deficiency is an autosomal recessive disorder (glycogenosis type XI, OMIM#612933) caused by mutations in the LDHA gene. We present two young adult female patients presenting with intolerance to anaerobic exercise, episodes of rhabdomyolysis, and, in one of the patients, psoriasis-like dermatitis. We identified in the LDHA gene a homozygous c.410C>A substitution that predicts a p.Ser137Ter nonsense mutation in Patient One and a compound heterozygous c.410C>A (p.Ser137Ter) and c.750G>A (p.Trp250Ter) nonsense mutation in Patient Two. The pathogenicity of the variants was demonstrated by electrophoretic separation of LDH isoenzymes. Moreover, a flat lactate curve on the forearm exercise test, along with the clinical combination of myopathy and psoriatic-like dermatitis, can also lead to the diagnosis.

5 ALA Is a Potent Lactate Dehydrogenase Inhibitor But Not a Substrate: Implications for Cell Glycolysis and New Avenues in 5 ALA-Mediated Anticancer Action

Simple Summary

In the present work, we found that 5-ALA, a natural precursor of heme, can hinder cell glycolysis, which is the main path of energy production for most cancer cells. More specifically, we found that 5-ALA can block an enzyme involved in glycolysis, called lactate dehydrogenase (LDH). We found that 5-ALA has a potency of LDH inhibition comparable to other established LDH inhibitors, such as oxamate or tartronic acid. Nevertheless, 5-ALA has a high accumulation rate in cancers and specifically in the incurable brain cancer glioblastoma multiforme (GBM), which is an important advantage. In fact, because of its high specificity to GBM, 5-ALA is used in the clinic to accurately guide the resection of the tumours, through the light emission of its photoactive product protoporphyrin IX (PpIX). PpIX is the penultimate step in the heme production. Importantly, we show here that continuous administration of 5-ALA killed GBM cells according to their dependence on glycolysis. We additionally found that 20% of externally administered 5-ALA is engaged in the inhibition of LDH, as when LDH was pre-loaded by another inhibitor, tartronic acid, then the cell production of PpIX from 5-ALA was increased by 20%. Since PpIX is an important drug for photodynamic therapy of cancer (excitation by light of PpIX produces oxygen by-products that can kill cancer cells), we additionally discovered that preloading LDH with its inhibitor tartronic acid before performing 5-ALA PDT increases the cancer cell death by 15%.

Abstract

In a course of metabolic experiments, we determined that the addition of δ-aminolevulinic acid (5-ALA) to a panel of glioblastoma multiforme (GBM) cells caused a steep reduction in their glycolytic activity. This reduction was accompanied by a decrease in adenosine triphosphate (ATP) production from glycolysis. These results suggested that 5-ALA is an inhibitor of glycolysis; due to the structural similarity of 5-ALA to the established lactate dehydrogenase (LDH) inhibitors oxamate (OXM) and tartronate (TART), we initially investigated LDH inhibition by 5-ALA in silico. The modelling revealed that 5-ALA could indeed be a competitive inhibitor of LDH but not a substrate. These theoretical findings were corroborated by enzymatic and cell lysate assays in which 5-ALA was found to confer a potent LDH inhibition comparable to that of OXM and TART. We subsequently evaluated the effect of 5-ALA-induced glycolysis inhibition on the viability of GBM cells with diverse metabolic phenotypes. In the Warburg-type cell lines Ln18 and U87, incubation with 5-ALA elicited profound and irreversible cell death (90–98%) at 10 mM after merely 24 h. In T98G, however, which exhibited both high respiratory and glycolytic rates, LD95 was achieved after 72 h of incubation with 20 mM 5-ALA. We additionally examined the production of the 5-ALA photosensitive metadrug protoporphyrin IX (PpIX), with and without prior LDH inhibition by TART. These studies revealed that ~20% of the 5-ALA taken up by the cells was engaged in LDH inhibition. We subsequently performed 5-ALA photodynamic therapy (PDT) on Ln18 GBM cells, again with and without prior LDH inhibition with TART, and found a PDT outcome enhancement of ~15% upon LDH pre-inhibition. We expect our findings to have a profound impact on contemporary oncology, particularly for the treatment of otherwise incurable brain cancers such as GBM, where the specific accumulation of 5-ALA is very high compared to the surrounding normal tissue.

Preoperative serum alpha-hydroxybutyrate dehydrogenase level as a predictor of postoperative mortality and morbidity after noncardiac surgery: A propensity-adjusted analysis

BACKGROUND

Preoperative serum alpha-hydroxybutyrate dehydrogenase is reportedly associated with myocardial infarction. Myocardial injury after noncardiac surgery is independently associated with postoperative mortality. However, the association between preoperative alpha-hydroxybutyrate dehydrogenase and outcomes after noncardiac surgery has not been researched. We aimed to assess the association between preoperative serum alpha-hydroxybutyrate dehydrogenase levels and mortality and morbidity after noncardiac surgery.

METHODS

We conducted a retrospective cohort study on patients undergoing noncardiac surgery from 2018 to 2020 in Sichuan University West China Hospital. After multivariate adjustment, the alpha-hydroxybutyrate dehydrogenase level was verified to be associated with postoperative outcomes by logistic regression analyses and propensity score weighting methods.

RESULTS

We obtained data from 130,880 patients. An elevated preoperative serum alpha-hydroxybutyrate dehydrogenase level was associated with increasing mortality (odds ratio 1.244, 1.190-1.300; P < .001), myocardial injury after noncardiac surgery (odds ratio 1.198, 1.141-1.257; P < .001), and intensive care unit admission (odds ratio 1.138, 1.111-1.166; P < .001) in logistic regression analyses. The covariate balancing generalized propensity score methodology demonstrated similar results. After classifying alpha-hydroxybutyrate dehydrogenase as a binary variable with a cut-off value of 182, we found that mortality, myocardial injury after noncardiac surgery, and intensive care unit admission >24 hours were significantly higher in the elevated alpha-hydroxybutyrate dehydrogenase group (5.458% vs 0.737%; odds ratio 1.771, 1.533-2.046; P < .001), (3.598% vs 0.572%; odds ratio 1.636, 1.393-1.922; P < .001), and (18.182% vs 6.442%; odds ratio 1.430, 1.327-1.542; P < .001), respectively. Similarly, the inverse-probability-of-treatment weighted estimation demonstrated similar results.

CONCLUSION

Our results suggest that the preoperative serum alpha-hydroxybutyrate dehydrogenase level was associated with in-hospital mortality, myocardial injury after noncardiac surgery, and intensive care unit admission after noncardiac surgery.

Cardiovascular manifestations in COVID-19 patients: A systematic review and meta-analysis

Since December 2019, the COVID-19 pandemic has affected the global population, and one of the major causes of mortality in infected patients is cardiovascular diseases (CVDs).For this systematic review and meta-analysis, we systematically searched Google Scholar, Scopus, PubMed, Web of Science, and Cochrane databases for all articles published by April 2, 2020. Observational studies (cohort and cross-sectional designs) were included in this meta-analysis if they reported at least one of the related cardiovascular symptoms or laboratory findings in COVID-19 patients. Furthermore, we did not use any language, age, diagnostic COVID-19 criteria, and hospitalization criteria restrictions. The following keywords alone or in combination with OR and AND operators were used for searching the literature: "Wuhan coronavirus", "COVID-19", "coronavirus disease 2019", "SARS-CoV-2", "2019 novel coronavirus" "cardiovascular disease", "CVD", "hypertension", "systolic pressure", "dyspnea", "hemoptysis", and "arrhythmia". Study characteristics, exposure history, laboratory findings, clinical manifestations, and comorbidities were extracted from the retrieved articles. Sixteen studies were selected which involved 4754 patients, including 2103 female and 2639 male patients. Among clinical cardiac manifestations, chest pain and arrhythmia were found to have the highest incidence proportion. In addition, elevated lactate dehydrogenase (LDH) and D-dimer levels were the most common cardiovascular laboratory findings. Finally, hypertension, chronic heart failure, and coronary heart disease were the most frequently reported comorbidities. The findings suggest that COVID-19 can cause various cardiovascular symptoms and laboratory findings. It is also worth noting that cardiovascular comorbidities like hypertension have a notable prevalence among COVID-19 patients.

Elevated α-hydroxybutyrate dehydrogenase as an independent prognostic factor for mortality in hospitalized patients with COVID-19

AIMS

Many studies have explored the clinical characteristics of patients with coronavirus disease (COVID-19), especially patients with cardiovascular disease. However, associated mechanisms and markers remain to be further investigated. This study aimed to investigate the effect of α-hydroxybutyrate dehydrogenase (α-HBDH) levels on disease progression and prognosis of patients with COVID-19.

METHODS AND RESULTS

One thousand seven hundred and fifty-one patients from the Leishenshan hospital in Wuhan were divided into elevated and normal groups by α-HBDH level, and the clinical information between the two groups was compared retrospectively. The main outcome evaluation criteria included in-hospital death and disease severity. Univariate and multivariate regression analyses, survival curves, logistic regression, and receiver operating characteristic curve models were performed to explore the relationship between elevated α-HBDH and the two outcomes. Besides, curve fitting analyses were conducted to analyse the relationship between computed tomography score and survival. Among 1751 patients with confirmed COVID-19, 15 patients (0.87%) died. The mean (SD) age of patients was 58 years in normal α-HBDH group and 66 years in elevated α-HBDH group (P < 0.001). The mortality during hospitalization was 0.26% (4 of 1559) for patients with normal α-HBDH levels and 5.73% (11 of 192) for those with elevated α-HBDH levels (P < 0.001). Multivariate Cox analysis confirmed an association between elevated α-HBDH levels and higher risk of in-hospital mortality [hazard ratio: 4.411, 95% confidence interval (95% CI), 1.127-17.260; P = 0.033]. Multivariate logistic regression for disease severity and α-HBDH levels showed significant difference between both groups (odds ratio = 3.759; 95% CI, 1.895-7.455; P < 0.001). Kaplan-Meier curves also illustrated the survival difference between normal and elevated α-HBDH patients (P < 0.001).

CONCLUSIONS

Our study found that serum α-HBDH is an independent risk factor for in-hospital mortality and disease severity among COVID-19 patients. α-HBDH assessment may aid clinicians in identifying high-risk individuals among COVID-19 patients.

COVID-19 and multiorgan failure: A narrative review on potential mechanisms

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) in December 2019 form Wuhan, China leads to coronavirus disease 2019 (COVID-19) pandemic. While the common cold symptoms are observed in mild cases, COVID-19 is accompanied by multiorgan failure in severe patients. The involvement of different organs in severe patients results in lengthening the hospitalization duration and increasing the mortality rate. In this review, we aimed to investigate the involvement of different organs in COVID-19 patients, particularly in severe cases. Also, we tried to define the potential underlying mechanisms of SARS-CoV2 induced multiorgan failure. The multi-organ dysfunction is characterized by acute lung failure, acute liver failure, acute kidney injury, cardiovascular disease, and as well as a wide spectrum of hematological abnormalities and neurological disorders. The most important mechanisms are related to the direct and indirect pathogenic features of SARS-CoV2. Although the presence of angiotensin-converting enzyme 2, a receptor of SARS-CoV2 in the lung, heart, kidney, testis, liver, lymphocytes, and nervous system was confirmed, there are controversial findings to about the observation of SARS-CoV2 RNA in these organs. Moreover, the organ failure may be induced by the cytokine storm, a result of increased levels of inflammatory mediators, endothelial dysfunction, coagulation abnormalities, and infiltration of inflammatory cells into the organs. Therefore, further investigations are needed to detect the exact mechanisms of pathogenesis. Since the involvement of several organs in COVID-19 patients is important for clinicians, increasing their knowledge may help to improve the outcomes and decrease the rate of mortality and morbidity.

Cardiac injury associated with severe disease or ICU admission and death in hospitalized patients with COVID-19: a meta-analysis and systematic review

BACKGROUND

Cardiac injury is now a common complication of coronavirus disease (COVID-19), but it remains unclear whether cardiac injury-related biomarkers can be independent predictors of mortality and severe disease development or intensive care unit (ICU) admission.

METHODS

Two investigators searched the PubMed, EMBASE, Cochrane Library, MEDLINE, Chinese National Knowledge Infrastructure (CNKI), Wanfang, MedRxiv, and ChinaXiv databases for articles published through March 30, 2020. Retrospective studies assessing the relationship between the prognosis of COVID-19 patients and levels of troponin I (TnI) and other cardiac injury biomarkers (creatine kinase [CK], CK myocardial band [CK-MB], lactate dehydrogenase [LDH], and interleukin-6 [IL-6]) were included. The data were extracted independently by two investigators.

RESULTS

The analysis included 23 studies with 4631 total individuals. The proportions of severe disease, ICU admission, or death among patients with non-elevated TnI (or troponin T [TnT]), and those with elevated TnI (or TnT) were 12.0% and 64.5%, 11.8% and 56.0%, and 8.2% and. 59.3%, respectively. Patients with elevated TnI levels had significantly higher risks of severe disease, ICU admission, and death (RR 5.57, 95% CI 3.04 to 10.22, P < 0.001; RR 6.20, 95% CI 2.52 to 15.29, P < 0.001; RR 5.64, 95% CI 2.69 to 11.83, P < 0.001). Patients with an elevated CK level were at significantly increased risk of severe disease or ICU admission (RR 1.98, 95% CI 1.50 to 2.61, P < 0.001). Patients with elevated CK-MB levels were at a higher risk of developing severe disease or requiring ICU admission (RR 3.24, 95% CI 1.66 to 6.34, P = 0.001). Patients with newly occurring arrhythmias were at higher risk of developing severe disease or requiring ICU admission (RR 13.09, 95% CI 7.00 to 24.47, P < 0.001). An elevated IL-6 level was associated with a higher risk of developing severe disease, requiring ICU admission, or death.

CONCLUSIONS

COVID-19 patients with elevated TnI levels are at significantly higher risk of severe disease, ICU admission, and death. Elevated CK, CK-MB, LDH, and IL-6 levels and emerging arrhythmia are associated with the development of severe disease and need for ICU admission, and the mortality is significantly higher in patients with elevated LDH and IL-6 levels.

Biomarkers of Cardiac Injury: An Update

Conventional and promising new markers of myocardial injury have become an important diagnostic tool and their prognostic significance is also recognized. In addition, they help identify patients who will derive the most benefit from therapeutic interventions. The literature was searched from the websites of the National Library of Medicine (http://www.ncbi.nlm.nih.gov/) and PubMed Central, the U.S. National Library of Medicine’s digital archive of life sciences journal literature (http://www.pubmedcentral.nih.gov/). The data were accessed from books and journals that published relevant articles in this field. The diagnosis of acute myocardial infarction (AMI) has traditionally relied on the combination of chest pain, ECG features, and elevation in serum markers. However, chest symptoms are frequently atypical or absent and ECG changes may be nonspecific or absent. Hence, the diagnosis of acute coronary syndromes has become increasingly dependent on serum markers of cardiac injury. Among them, creatine kinase (CK) is an effective and widely used test, with the recent CKMB assay offering greater specificity and sensitivity. Cardiac troponins facilitate early and rapid diagnosis, enable effective risk stratification in patients with AMI (with or without traditional criteria for MI), and identify those who will benefit from aggressive medical or surgical intervention. Recent data suggest the potential of myoglobin and CKMB isoforms as sensitive markers in the early hours after symptom onset. Cardiac-specific troponins help in rapid diagnosis, prognostication, and treatment of AMI. Troponins also facilitate early detection of recent infarction owing to their prolonged diagnostic window and also aid in the detection of “microinfarction.” CKMB is used to detect reinfarction or infarct extension, if levels rise again after declining. Finally, novel biochemical markers are receiving attention in ongoing trials. They may prove to be more effective in diagnosis and prognosis than their existing counterparts.

Relation of serum lactate dehydrogenase to coronary artery disease

Serum lactate dehydrogenase (LDH) is known pathologic marker for a diversity of diseases, including myocardial ischemia. Strenuous and enduring physical activity can transiently induce a greater total LDH level, still within its normal range. To date, however, it has not been determined whether normal-range LDH might be inversely associated with coronary artery disease (CAD) in the low-cardiovascular-risk, physically active, adult population. We conducted a retrospective cohort analysis. A total of 5,519 healthy adults aged 34 to 86 years were followed up for a mean period of 4.2 years. The cohort incidence of CAD was 6.1% (338 cases) from 2001 to 2009. In the present cohort, greater mean LDH levels were significantly associated with a greater number of years, days/week, and minutes/week of leisure time activity (p = 0.02, p = 0.04, and p = 0.01, respectively). These associations were externally validated successfully by analysis of all 5,064 healthy participants aged ≥40 years with normal-range LDH from the 2007 to 2010 National Health and Nutrition Examination Surveys combined. For instance, the mean LDH level was significantly greater in those engaged in 6 to 7 versus 1 to 5 days/wk of vigorous-intensity work activity (138.0 ± 20.7 IU/L vs 133.3 ± 21.7 IU/L, respectively, p = 0.007). In our cohort, the hazard ratio for CAD according to the normal total serum LDH tertiles, adjusted for multiple risk and protective CAD factors in a Cox proportional hazards model, was 0.70 (95% confidence interval 0.54 to 0.92) in the greater versus lower tertile (p for trend = 0.01). In conclusion, we suggest that increased normal-range total serum LDH is associated with reduced short-term risk of CAD outcome in this low-risk, physically active population.

Genome-wide linkage and association scans for quantitative trait Loci of serum lactate dehydrogenase-the framingham heart study

Serum lactate dehydrogenase (LDH) is used in diagnosing many diseases and is significantly determined by genetic factors. Three genes coding for LDH isoenzymes were mapped to chromosome 11q15 and 12p12. We used 330 Framingham Heart Study largest families for microsatellite linkage scan and 100K SNPs association scan to determine quantitative trait loci of LDH level. We estimated the heritability at 41%. Our genome-wide linkage analysis yielded several chromosomal regions, other than 11q and 12p, with LOD scores between 1 and 2.5. None of the 100K SNPs with a P-value <10(-4) in our genome-wide association study was close to the chromosomal regions where the LDH genes reside. Our study demonstrated a strong genetic effect on the variation of LDH levels. There may not be a single gene with a large effect, instead may be several genes with small effects in controlling the variation of serum LDH. Those genes may be located on chromosomal regions that differ from where the genes encoding LDH isoenzymes reside.

Effects of hydrolyzed Chlorella vulgaris by malted barley on the immunomodulatory response in ICR mice and in Molt-4 cells

BACKGROUND

Chlorella vulgaris is a unicellular and microscopic algae that is currently used in a variety of forms of tablets, capsules and liquid as a biological response modifier. The aim of this study was to investigate the effects of hydrolyzed Chlorella vulgaris by malted barley for its potential reduction of the immobility time in ICR mice and on the cytokine regulation in human T cell line, Molt-4.

RESULTS

After a forced swimming test, the changes in aspects of blood biochemical parameters due to the administration of hydrolyzed Chlorella vulgaris by malted barley were examined. The effect of hydrolyzed Chlorella vulgaris by the malted barley-treated group for 14 days on the immobility time was significantly reduced in comparison with that of the control group (P < 0.01). The plasma level of blood urea nitrogen was significantly decreased in hydrolyzed Chlorella vulgaris by malted barley-treated group compared with the control group (P < 0.05). In addition, hydrolyzed Chlorella vulgaris by malted barley increased interferon-gamma and interlukin-2 levels in Molt-4 cells.

CONCLUSION

These results indicate that hydrolyzed Chlorella vulgaris by malted barley is useful for immune function improvements, enhanced physical stamina, and as a candidate for an anti-fatigue or antidepressant agent.

Improving the early diagnosis of acute myocardial infarction

The diagnosis of early myocardial infarction, especially in association with atypical clinical presentations, can be difficult to establish. Continued observation of high-risk patients, with multiple serial electrocardiographs and the use of other diagnostic modalities as available, is essential to prevent the inadvertent premature discharge of patients with evolving myocardial infarcts from the accident and emergency department.

Cardiac enzymes. How to use serial determinations to confirm acute myocardial infarction

Although acute myocardial infarction can be diagnosed on the basis of clinical history, electrocardiographic (ECG) findings, and abnormalities of creatine kinase (CK) and lactate dehydrogenase (LDH) enzyme levels, measurement of cardiac enzyme levels is the most reliable way to confirm or exclude the diagnosis. If the MB isoenzyme of creatine kinase (CK-MB) remains normal during the 48 hours after the suspected clinical event, acute myocardial infarction can be reliably ruled out; if CK-MB values become elevated and the LDH isoenzyme pattern (LDH2:LDH1 ratio) becomes "flipped," the diagnosis can reliably be made. However, if CK-MB values become elevated but the LDH isoenzyme pattern remains normal, the diagnosis is less firm and ECG and myocardial imaging techniques may be needed to confirm or exclude myocardial infarction.

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.

[Crotalid bites in children: clinical, laboratory, epidemiologic aspects and treatment approach]

At the Hospital of Clinics of the Faculty of Medicine of Ribeirão Preto/USP during the years 1980-1989 21 children have been attended after rattlesnake bite: 16 severe and 5 with moderate envenomation. Four (20%) developed acute tubular necrosis 2 necessitating dialysis. One patient died 13 days after the bite and grave complications including digestive hemorrhage and acute respiratory insufficiency. All patients preserved clinical laboratory and epidemiological characteristics of Crotalus durissus terrificus envenomation. We also comment on the correct management of such patients specially related to antivenin dosage and the prevention of acute tubular the most serious complication of such an accident.

Acute myocardial infarction-like enzyme profile in human victims of Crotalus durissus terrificus envenoming

The clinical signs and symptoms of Crotalus durissus terrificus envenoming are due to the neurotoxic, myotoxic systemic and thrombin-like coagulating effects of the venom. The rhabdomyolysis observed after envenoming caused by snakes, the venom of which has a systemic myotoxic activity, has been limited thus far to skeletal muscle, with no reports of myocardial damage. In the present paper we report serial measurements of serum creatine kinase (CK), lactic dehydrogenase (LD) and of CK-MB and LD1 isoenzymes in human victims of Crotalus bites. The results were similar to those reported for acute myocardial infarction even though the clinical evolution, electrocardiogram and echocardiogram findings did not show any involvement of cardiac muscle. The enzymatic profile detected, as well as the pattern of focal involvement observed in muscle biopsies obtained from these patients, suggest that there may be a type of skeletal muscle fibre that is preferentially damaged by C. durissus terrificus venom, i.e., type I and/or IIa fibres, the composition of which is richer in CK-MB and LD1, and is similar to that of cardiac fibres.

Lactate dehydrogenase isoenzymes

The analytical procedures for LD isoenzymes include electrophoresis, chromatography, immunochemical and kinetic methods. Electrophoretic methods are generally preferred because the resulting patterns are directly observable and all five isoenzymes are resolved in a single procedure. Chromatographic methods, with the introduction of HPLC, have recently been perfected in terms of speed, resolution, precision and accuracy. Immunochemical methods and kinetic methods are attractive because of their speed and simplicity. Therefore, the latter methods are used mainly for assaying acute myocardial infarction, where generally the determination of LD-1 and LD-2 is sufficient. In all other instances, however, electrophoretic separation is currently preferred. Ion-exchange high-performance procedures are useful prospects, particularly in view of their velocity in comparison with electrophoresis. In general, the LD isoenzymes assay contributes considerably to diagnosis, but the results must be used with an adequate knowledge of biochemistry, physiology and the advantages and drawbacks of the different assay methods used.

Usefulness of lactate dehydrogenase and lactate dehydrogenase isoenzymes for diagnosis of acute myocardial infarction

The usefulness of lactate dehydrogenase (LD) and LD isoenzymes in the diagnosis of acute myocardial infarction (AMI) is controversial. The present study reviewed 507 consecutive patients in whom creatine kinase, creatine kinase isoenzymes, LD and LD isoenzymes were ordered over a 1-month period. Of these, 249 had an insufficient number of serial enzyme determinations to establish a laboratory diagnosis of AMI. After excluding an additional 11 patients for other reasons, 247 patients remained for analysis. Of these, only 2 (0.8%) had myocardial infarction by standard clinical criteria with normal creatine kinase and creatine kinase-MB but elevated LD and abnormal LD isoenzymes. Seven patients (7 of 247, 2.8%) had false-positive LD isoenzymes. Thus, the routine use of LD and LD isoenzymes was of no use in most patients (96%) and led to the incorrect diagnosis of AMI more than 3 times as often as it helped with a correct diagnosis. Total 1-month charges for all the LD and LD isoenzymes obtained equalled +42,450. Therefore, it appears that LD and LD isoenzymes are not routinely useful in the diagnosis of AMI and may result in considerable unnecessary expense. It is suggested that LD and LD isoenzymes be ordered only under suspicion of late presentation (greater than 48 hours) of AMI.

"Flipped" lactic dehydrogenase pattern in acute coronary insufficiency

Serum lactic dehydrogenase (LDH) isoenzymes were measured 24, 48, and 72 hours after administration in 85 patients with acute coronary insufficiency (ACI) and 10 patients with stable angina pectoris who served as controls. The above patients did not develop myocardial infarction according to the criteria of development of new Q waves or elevation of cardiac enzymes. In 15 patients with ACI a "flipped" LDH pattern (LDH1 greater than LDH2) was found in the presence of normal total LDH activity and normal creatine kinase-MB. The values of LDH 1:2 ratio ranged between 1.02 and 1.13 (normal values 0.45-0.75). In the 10 control patients, normal levels of total LDH and normal LDH enzyme distribution and creatine kinase-MB were found. A possible explanation for the flipped LDH pattern in the ACI patients (indicating some myocardial damage) could be myocytolysis and coagulation necrosis found on postmortem examinations. The conclusion of our study is that LDH isoenzymes should be measured in patients with ACI to determine the LDH 1:2 ratio. The finding of a "flipped" LDH pattern demonstrating myocardial damage, lacking in stable angina, may also be helpful in patients who developed the clinical picture of ACI more than 24 hours before arrival at the hospital, since by that time the creatine kinase-MB may have already returned to normal. An additional advantage of measuring LDH isoenzymes in these patients may be that patients with "flipped" LDH pattern may need a longer rest and earlier coronary angiographic evaluation.

Late estimation of myocardial infarct size by total creatine kinase nomogram

We studied the possibility of enzymatic estimation of myocardial infarct size in patients late (between days 2 and 6) after the onset of acute myocardial infarction (AMI), in whom estimation of infarct size was difficult by analysis of time-activity curves of serum creatine kinase (CK) because of the lack of the enzymatic information during the initial 48 hours. Serial determinations of serum enzymes were performed in 32 patients within 6 hours after the onset of AMI and significantly close correlations were observed between cumulative total CK release and the cardiac fraction of lactate dehydrogenase isoenzyme (LDH1) activities from day 2 to day 6 after the onset of AMI (r = 0.863 to 0.870; p less than 0.001). We developed a nomogram to estimate cumulative total CK release by serum LDH1 activities obtained between days 2 and 6 after AMI and evaluated the reliability of the nomogram. Cumulative total CK release obtained from serial serum CK activities correlated closely with total CK release obtained from the nomogram in the second group of patients with AMI (r = 0.923 to 0.946; n = 24; p less than 0.001). Our total CK nomogram requiring few blood samples was useful in late estimation of infarct size in patients who were admitted to the hospital between days 2 and 6 after the onset of AMI.

Validation of technetium-99m stannous pyrophosphate myocardial scintigraphy for diagnosing acute myocardial infarction more than 48 hours old when serum creatine kinase-MB has returned to normal

Determination of lactic dehydrogenase (LDH) isoenzymes is the current method of choice for diagnosing acute myocardial infarction (AMI) greater than 48 hours old. However, other causes of enzyme elevation make the availability of an alternate method of diagnosis worthwhile. Accordingly, serial technetium-99m pyrophosphate scintigrams were obtained in 61 patients with transmural AMI and in 46 patients with subendocardial AMI. Imaging was performed in all 107 patients at the time creatine kinase isoenzyme (CK-MB) was present 37 +/- 18 hours (range 12 to 72) after the onset of AMI, and at the time CK-MB was absent 106 +/- 34 hours (range 48 to 168) after the onset of AMI. At the time CK-MB was absent, the sensitivity using either a regional or a diffuse positive scintigram was 95% (58 of 61 patients) for transmural AMI and 65% (30 of 46 patients) for subendocardial AMI. The sensitivity using a regional positive scintigram was 82% (50 of 61 patients) for transmural AMI and 37% (17 of 46 patients) for subendocardial AMI. The sensitivity using a high-grade regional positive scintigram was 36% (22 of 61 patients) for transmural AMI and 11% (5 of 46 patients) for subendocardial AMI. The specificity was 70% (143 of 204 patients) for either a regional or a diffuse abnormality, 92% (187 of 204 patients) for a regional abnormality, and 100% (204 of 204 patients) for a high-grade regional abnormality. Thus, pyrophosphate scintigraphy is useful in confirming the diagnosis of AMI, particularly transmural, greater than 48 hours old and when CK-MB has returned to normal. A positive scintigram with a high-grade regional abnormality is specific for a recent AMI and may be contributory in establishing the diagnoses when LDH isoenzymes are inconclusive.

Abnormal cardiac enzyme responses after strenuous exercise: alternative diagnostic aids

Serial estimations of activities of creatine kinase and its MB isoenzyme, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase and of concentrations of alpha(1)-acid glycoprotein were performed in 15 healthy well-trained male marathon runners. Estimations were made initially within three days before a race and then one, 24, and 96 hours after the race. Technetium-99m pyrophosphate myocardial scintigraphy was carried out at the initial prerace assessment and repeated 48 to 96 hours after the race. None of the subjects developed cardiac symptoms during or after the race.Activities of creatine kinase and creatine kinase MB became maximal 24 hours after the race. One and 96 hours after the race two and five subjects, respectively, showed amounts of creatine kinase MB totalling 5% or more of total creatine kinase. Lactate dehydrogenase activity peaked at one hour after the race, and activities of aspartate and alanine aminotransferases peaked at 24 and 96 hours after the race, respectively. Activities of all these enzymes showed a significant increase from prerace values during the rest of the study. Electrocardiographic features noted were similar to those reported elsewhere in athletes under similar conditions. They included first-degree heart block, incomplete right bundle-branch block, left ventricular hypertrophy, pseudoischaemic T-wave changes, and early repolarisation of variant ST-segment elevations in precordial leads. Technetium-99m pyrophosphate myocardial scintigraphy did not show evidence of myocardial damage before or after the race. Alpha(1)-acid glycoprotein concentrations were normal throughout.These data suggest that reliance on standard enzyme estimations and electrocardiographic criteria may yield false-positive indicators of myocardial injury during prolonged strenuous exercise. Technetium-99m pyrophosphate scintigraphy and alpha(1)-acid glycoprotein measurements offer additional information and may usefully be employed in evaluating circulatory collapse associated with such exercise.

Histologic, ultrastructural, and enzymatic measurements of infarct size following coronary artery stenosis and occlusion

Coronary artery narrowing (CAN), which reduced resting coronary blood flow (BF) by 50%, was induced in 10 conscious dogs and was maintained for 4 hours. Five additional dogs (group 1) with complete coronary artery occlusion were compared to the dogs with CAN. Serum isoenzymes of creatine phosphokinase (CK) and lactate dehydrogenase (LD) were monitored hourly in all groups. After 36 hours, samples were obtained for regional myocardial BF, quantitative histology, and quantitative ultrastructural (EM) morphology. Six dogs with CAN had small infarcts (MI) of less than 1 gm and persistent myocardial cell injury (group 2). The other four dogs with CAN has only persistent myocardial cell injury by ultrastructural criteria (group 3). Peak serum CK activities in groups 2 and 3 were similar, as well MI sizes calculated from serum CK and myocardial depletion. MB CK was of diagnostic value in group 1 but not in groups 2 and 3. The ratio of LD 1/LD 2 had diagnostic value in all three groups. MI size by enzyme estimates was consistently higher than planimetered MI size at autopsy in both groups 1 and 2. All three groups had significant amounts of ultrastructural damage outside of histologically demonstrated. MI. These findings suggest that (1) gross and histologic MI size determination of 36 hours after ischemia underestimate extent of damage, and (2) ultrastructural cell changes cause significant release of CK and LD in coronary disease (CAD).

A rapid and simple procedure for the preparation of human lactate dehydrogenase-2 from erythrocytes using an ion-exchange mini-column

We describe a simple ion-exchange chromatography technique for the rapid preparation of lactate dehydrogenase-2 from lysed human erythrocytes obtained either from plasma or serum clots. The procedure appears capable of scale-up to larger columns thus making it ideal as an initial step in a more extensive purification scheme.