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

The Role of Protein Degradation in Estimation Postmortem Interval and Confirmation of Cause of Death in Forensic Pathology: A Literature Review

It is well known that proteins are important bio-macromolecules in human organisms, and numerous proteins are widely used in the clinical practice, whereas their application in forensic science is currently limited. This limitation is mainly attributed to the postmortem degradation of targeted proteins, which can significantly impact final conclusions. In the last decade, numerous methods have been established to detect the protein from a forensic perspective, and some of the postmortem proteins have been applied in forensic practice. To better understand the emerging issues and challenges in postmortem proteins, we have reviewed the current application of protein technologies at postmortem in forensic practice. Meanwhile, we discuss the application of proteins in identifying the cause of death, and postmortem interval (PMI). Finally, we highlight the interpretability and limitations of postmortem protein challenges. We believe that utilizing the multi-omics method can enhance the comprehensiveness of applying proteins in forensic practice.

Trifluralin toxicity in a Chagas disease mouse model

Even though trifluralin (alpha,alpha,alpha-2,6-dinitro-N-N-dipropyl-p-toluidine) is effective for the treatment of experimental Chagas disease, more preclinical toxicity studies need to be performed. Cell toxicity of trifluralin was studied in Hep-G2 and Vero C76 cells treated with 50 and 150 microM trifluralin. The results show that duplication time, amount of cellular protein and cell protein/DNA values were normal. Histological, haematological and chemical parameters were measured in CF1 mice after oral trifluralin administration. Acute toxic effects were assayed by administration of 50 or 200 mg/kg body weight daily for 30 days, and chronic effects by administration of 200 mg/kg body weight once a week for 90 days (n = 20). In the acute scheme treatment, hepatic (glutamic-pyruvic, glutamic-oxalacetic and alkaline phosphatase activities; proteins and albumin plasma concentrations) and pancreatic (amylase, glycaemia) functions were normal. Mean corpuscular volume, haemoglobin and haematocrit decreased. Creatine phosphokinase, lactate dehydrogenase and glutamic-oxalacetic activity increased, suggesting lesion in myocardial tissue. Histology was normal, excepting for the heart (mild myocarditis). Similar results were observed in acutely treated animals. There were no differences in body weight gain for treated mice compared to controls. In view of the published therapeutic effects of trifluralin on CF1 Chagas disease model and considering the present results, trifluralin seems to be a moderately toxic drug with a potential selective effect on the myocardium.

Cardiac myofibrillar proteins: biochemical markers to estimate myocardial injury

Ischaemic heart disease represents the most common of the serious health problems in the contemporary society and acute myocardial infarction (AMI) is the major cause of cardiovascular morbidity and death. The accurate localization and determination of the infarct size and the volume of myocardium at risk at the time of insult is crucial and vital for the choice of treatment. Initially the ischaemic cells are reversibly injured. However, if these changes are not reverted at the earliest, it results in the death of the myocyte. This irreversible myocyte necrosis travels transmurally towards epicardium in the form of a wavefront. A timely intervention during evolving infarct could reduce and delimit the infarct and preserve the left ventricular function. Enzyme analysis and electrocardiography (ECG) along with the clinical history of the patient is still considered to constitute a reliable triad in the diagnosis of myocardial infarction (MI). Efforts have been made to relate infarct size with the serum enzyme level changes without much success. In addition, a number of specialist techniques such as planar radioisotope imaging, single photon emission computed tomography (SPECT), positron emission tomography (PET), Echocardiography, Ventriculography and nuclear magnetic resonance (NMR) imaging have been devised to support diagnosis in the patients who show ambiguous symptoms and ECG findings. However most of these procedures are unavailable to the patients due to economic reasons while others have suffered due to non-availability of ideal radiopharmaceuticals. Major advances have been made in the methods based on immunological techniques to improve the detection and estimation of infarct. These methods are exclusively based upon the production and availability of specific antibodies against intracellular, cardiac specific components.

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.

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.