Genetic control of lactate dehydrogenase and malate dehydrogenase isozymes in cultures of lymphocytes and granulocytes: effect of addition of phytohemagglutinin, actinomycin D or puromycin

Biochemical analysis of pancreatic fluid collections predicts bacterial infection

BACKGROUND AND AIMS

Despite our understanding of the pathophysiology of different types of pancreatic fluid collections (PFC), few studies have attempted to correlate the biochemical analysis of PFC contents with clinical and radiological characteristics. The aim of this study was to assess the predictive value of fluid analysis for discerning collection type (pseudocyst vs acute fluid collection with necrosis), presence of infection or communication with the pancreatic duct in the setting of acute and chronic pancreatitis.

METHODS

Pancreatic fluid from 34 consecutive patients undergoing endotherapy of PFC was prospectively analyzed for seven variables: lactate dehydrogenase (LDH), total protein, albumin, glucose, amylase, lipase and specific gravity.

RESULTS

In multivariate analysis, adjusting for age and gender, high intracystic levels of protein (OR 6.2; 95% CI 1.3-37.0), LDH (OR 6.8 [2.3-38.3]), and albumin (OR 7.8 [1.3-67.4]), and low levels of glucose (OR 0.2 [0.03-0.9]) predicted the presence of PFC infection. The optimal threshold value for protein was 1000 g/dL, which achieved a sensitivity of 73% and specificity of 75% for detecting infection; the optimal cut-off for LDH was 1000 U/L (sensitivity 64%, specificity 85%), and the cut-off for albumin was 500 g/dL (sensitivity 75%, specificity 85%). There were no statistically significant differences in biochemical fluid analysis with respect to fluid collection type (pseudocysts vs acute fluid collection with necrosis) and the presence of pancreatic duct communication.

CONCLUSIONS

Biochemical analysis of PFC fluid is clinically helpful in detecting fluid infection in patients with bacteria on Gram stain or positive fluid cultures. Our findings fail to support the utility of fluid analysis in characterizing cyst type, and we caution against its use in distinguishing pseudocysts from acute fluid collection with necrosis.

Regulation of the expression of lactate dehydrogenase isozymes in human lymphocytes

Mitogen activation of human peripheral lymphocytes leads to a switch in the isozymes of LDH; resting cells contain low activities of only the B4 and B3A forms, whereas activated cells contain high activities of the A4 and A3B forms. B4 LDH is not altered in activated cells. In this study we show that the appearance of the A subunits occurs concomitantly with a several fold increase in the steady state levels of LDH-A mRNA. Responses in LDH-A mRNA are observed within 12 hrs of activation, and are, thus, associated with the G0/G1 transition or with early G1 (Marjanovic et al. Exp. Cell Res. (1991) 193: 425-431). Maximal expression of LDH-A mRNA requires both phorbol ester and concanavalin A, implying a complex regulatory pathway involving cascade systems activated through both the antigen receptor (TR) and protein kinase C.

Expression of a new set of glycolytic isozymes in activated human peripheral lymphocytes

The combination of phorbol 12-myristate 13-acetate (PMA) and concanavalin A induces the expression of a new set of glycolytic isozymes in human peripheral lymphocytes. The induced isozyme for each enzyme tested (hexokinase, phosphofructokinase, enolase, pyruvate kinase and lactate dehydrogenase) is usually the muscle form, which is often associated with rapidly dividing tumor cells. Increases in a specific isozyme can account for the 2-5-fold increase in specific activities of the enzyme induced by Con A plus PMA. Increased specific activities and the appearance of the new isozyme forms both occur relatively late, and are probably associated with the G1 or S phase of the cell cycle.

Changes in the activity and isozyme patterns of glycolytic enzymes during stimulation of normal human lymphocytes with phytohaemagglutinin

A study has been made of the effects of phytohaemagglutinin on the gene expression of the glycolytic enzymes in cultured human lymphocytes. All the enzymes were found to show an average increase in activity of between 160% and 360% in stimulated cells, but the increases were greater for the enzymes comprising the second half of the pathway. The enzyme activities in stimulated cells, cultured for 72 h, were similar to the activities measured in long-term lymphoid lines. Starch-gel electrophoresis was used to examine the isozyme patterns of the enzymes before and after exposure of the lymphocytes to PHA. Six of the enzymes showed isozyme patterns unchanged by stimulation. Four of the enzymes, aldolase, triosephosphate isomerase, enolase and lactate dehydrogenase, showed different isozyme patterns in stimulated cells from those seen in uncultured or unstimulated cells. The electrophoretic results showed a good correlation in isozyme pattern between uncultured lymphocytes and cultured unstimulated lymphocytes, and between PHA-stimulated lymphocytes and long-term lymphoid lines.