Usefulness and Potential Pitfalls of Sialic Acid Determination in Sera of Patients with Ovarian Tumors

A New Procedure for Gangliosidic N-Acetylneuraminic Acid Analysis in Serum

In this paper a method is presented which is suitable for the extraction, purification and analysis of serum gangliosides. The advantage in comparison with other previously published procedures is the complete extraction of sialoglycolipids without contamination of sialoglycoproteins and/or sialoglycopeptides. The method could be used as a second-level test for the diagnosis and follow-up of cancer patients, and also could be potentially used for pharmaco-kinetic studies after ganglioside treatment.

Serum selenium, vitamin E, and sialic acids concentrations in lambs with white muscle disease

The aim of this study was to determine the serum concentrations of selenium, vitamin E, and total- and lipid-bound sialic acid (LBSA) in lambs with white muscle disease (WMD) before and after treatment with a commercial preparation containing selenite and vitamin E. Fifteen lambs with WMD and ten control animals were used as research materials. Blood samples were collected from both groups before- and 1 month after treatment for Se analysis by fluorimetry, whereas vitamin E and sialic acid were measured by HPLC and spectrophotometry, respectively. Compared to controls, in the diseased animals, there was a significant increase of serum total sialic acid (TSA) and LBSA, together with significant decreases of serum Se and vitamin E concentrations (p < 0.001). One month after treatment, a reversal of trend was observed with decreases of TSA and LBSA and increases of Se and vitamin E concentrations. The TSA and LBSA levels, however, remained significantly higher than those of the controls, p < 0.05 and 0.001, respectively. The Se and vitamin E concentrations of the treated animals were the same as those of controls. This is the first study on total and LBSA concentrations in lambs with WMD, showing that these markers can be used in the prognosis of the disease.

A re-evaluation of the lipid-bound sialic acid determination

The origin of serum sialic acid measured in the lipid-bound sialic acid determination reported by Katopodis et al. (1980) was investigated in detail. By varying the experimental conditions of sample preparation the protein, lipid and sialic acid contents of the methanol-water extract obtained from human sera were analyzed and compared in healthy controls and cancer patients. Using polyacrylamide gel electrophoretic and gel chromatographic methods it has been shown that most of the lipid-bound sialic acid was attributed to the acid alpha 1-glycoprotein (orosomucoid) fraction of human sera. Based on these observations a re-evaluation of the molecular background of the LBSA determination seems to be necessary.

Malignant cell glycoproteins and glycolipids

The cell surface is involved in cell growth and division, cell-cell interaction, communication, differentiation and migration, and other processes likely to be involved in malignant transformation and/or the metastatic spread of cancer. Although there are many alterations of glycoproteins and glycolipids on the malignant cell surface, it is unclear whether these alterations are epiphenomena or an integral part of the malignancy process. This article reviews the recent literature and some earlier studies relevant for understanding emerging concepts and trends with respect to malignant cell glycoconjugates. Emphasis is on structural alterations of the carbohydrate portions of malignant cell glycoproteins and glycolipids and on the enzymes (glycosyltransferases and glycosidases) involved in their metabolism. Practical applications derived from malignant cell glycoconjugate studies are discussed briefly with respect to the diagnosis, staging, monitoring, and treatment of malignant disease. The review concludes by indicating which research areas on malignant cell glycoconjugates are likely to be fruitful in increasing our basic understanding of, and ability to deal effectively with, malignant disease.

Sialic Acid, Ferritin and CEA Levels in Peripheral Blood and Blood Draining from the Tumor in Breast Cancer

Concentrations of total serum N-acetyl-neuraminic acid, carcinoembryonic antigen, ferritin, lactate dehydrogenase, creatine phosphokinase and total proteins were measured in both tumor drainage blood (axillary vein) and in peripheral blood taken during surgery from 44 breast cancer patients.

There were no significant differences in any of the markers between mean values in peripheral and tumor drainage blood, between cancer patients and healthy controls, between patients with or without axillary lymph node metastases, or according to the site of breast mass.