Markers lactate dehydrogenase

Lactate dehydrogenase (LDH) is a nonspecific marker of hepa-tocyte damage disproportionate elevation of LDH indicates ischemic injury. 

Plasma hormones and enzymes of testicular origin were used as markers for evaluation of acute testicular toxicity in rats treated with 1,3-DNB. Lactate dehydrogenase isozyme C4 (LDH-C4) and ABP were both elevated after treatment with doses between 10 and 25 mg/kg of 1,3-DNB (Reader et al. 1991). Testosterone levels were reduced after treatment with 10 and 32 mg/kg of 1,3-DNB (Reader etal. 1991 Rehnberg et al. 1988). 

Several markers should no longer be used to evaluate cardiac disease, including aspartate aminotransferase, total CK, total lactate dehydrogenase (LDH), and LDH isoenzymes. Due to their wide tissue distribution, these markers have poor specificity for the detection of cardiac injury. Because total CK and CK-MB have served as standards for so many years, some laboratories may continue to measure them to allow for comparisons to cardiac troponin over time, before discontinuing use of CK and CK-MB. In addition, the use of total CK in developing countries may be the preferred or only alternative for financial reasons. However, it should be clear that, for monitoring ACS patients to assist in clinical classification, cardiac troponin is the preferred biomarker. 

Other enzymes (lactate dehydrogenase, LDH, and aspartate aminotransferase, AST) also indicate tubular injury when present in the urine but they cannot be localized to a specific nephron segment. Despite this, LDH is commonly used as a marker for distal tubular injury (Price 1982 Guder and Ross 1984 Clemo 1998). 

The elevations of the germ cell tumour markers P-human chorionic gonadotrophin (P-HCG), a-fetoprotein (AFP) and lactate dehydrogenase (LDH) further support the working diagnosis of testicular cancer. The levels of P-HCG and AFP in particular are negligible in males in normal circumstances, but they are raised in patients with testicular cancers as the tumours secrete these substances in large quantities. 

Another approach to overcome assay chemistry incompatibility is splitting a sample into two different containers. If the cell population releases a marker into the surrounding environment, a small aliquot of culture medium can be sampled and moved to a different assay plate to segregate assay chemistries. Figure 6.11 shows the measurement of lactate dehydrogenase released from a... 

A number of other lines of evidence also suggested that there may be another mode-of-action for BTI poisoning by injection other than its known, general cytolytic activity (3,22-24). Using the appearance of cytosolic lactate dehydrogenase (LDH) in insect hemolymph post-injection as a marker for cytotoxicity (36-37), we found that dissolved BTI 6-endotoxin was a potent cytotoxin. When T. ni, however, were injected with dissolved BTI 5-endotoxin and then incubated at 28, 15, and 9°, there was an increase in the LD50 with a decrease in temperature (Figure 2) but the LDH levels at 3.5 PPM BTI were unaffected by temperature. 

Legrand C, Bour JM, Jacob C, Capiaumont J, Martial A, Marc A, Wudtke M, Kretzmer G, Demangel C, Duval D Hache J (1992) Lactate dehydrogenase (LDH) activity of the number of dead cells in the medium of cultured eukaryotic cells as marker. Journal of Biotechnology 25 231-243. 

Lactate dehydrogenase is a useful marker because it is released upon cell death and is stable over short periods of time (5% loss per day) (Wagner et al, 1992), so that the concentration of LDH in the medium provides an estimate of the total number of (intact plus lysed) dead cells. Equations 4.2.1-4.2.5 are still valid, but a balance needs to be included for the effective cell concentration which is equal to the total cell concentration plus the concentration of cells that have lysed (i.e. what the total cell concentration would be if no cells had lysed) ... 

The myocardium contains bundles of striated muscle fibers, each of which is typically 10 to 15 pm in diameter and 30 to 60 pm in length. Work of the heart is generated by the alternating of the contraction and relaxation of these fibers. The fibers are composed of cardiac-specific contractile proteins actin and myosin, and regulatory proteins caEed troponins. They also contain a variety of enzymes that are vital for energy use, such as myoglobin, creatine kinase (CK), and lactate dehydrogenase (LD), some of which can be used as markers of cardiac injury. 

There are five enzymes that are commonly used in diagnosis of liver disease Aspartate aminotransferase (AST EC 2.6.1.1), alanine aminotransferase (ALT EC 2.6.1.2), alkaline phosphatase (ALP 3.1.3.1), and y-glutamyl transferase (GGT EC 2.3.2.2), are commonly used to detect liver injury, and lactate dehydrogenase (LD EC 1.1.1.27) is occasionaEy used. ALT and GGT are present in several tissues, but plasma activities primarily reflect liver injury. AST is found in liver, muscle (cardiac and skeletal), and to a liipited extent iti fed cells. LD has wide tissue distribution, and is thus relatively nonspecific. ALP is found in a number of tissues, but in normal individuals primarEy reflects bone and liver sources. Thus based on tissue distribution, ALT and GGT would seem to be the most specific markers for liver injury. 

The alternative to dye exclusion as a measure of membrane integrity is the capability of the plasma membrane to retain a marker molecule. The marker can be the appearance in the medium of an intracellular molecule, such as an intracellular enzyme like lactate dehydrogenase (LDH). LDH release has been used for fish cell lines184, but experience with mammalian cells suggests that the use of LDH can be complicated by several factors162. 

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