Serum sialic acid concentration as a useful biochemical marker for early detection of nephropathy in insulin dependent diabetic children

Elevated serum sialic acid concentration is a strong predictor of cardiovascular morbidity in non-diabetic subjects. Because patients with insulin dependent diabetes mellitus [IDDM] and albuminuria have a highly increased cardiovascular morbidity and mortality, this study hypothesized that IDDM patients with albuminuria would have an increased concentration of serum sialic acid. One hundred children and adolescents were selected and divided into a diabetic group [n-75] and a healthy control group [n=25]. The diabetic group was further subdivided into three IDDM groups according to the duration of diabetes. Serum sialic acid, fasting blood sugar, HbAIc, creatinine, and urea were assayed in the blood. Microalbumi-nuria was assayed in urine. The mean value of total serum sialic acid concentration, fasting blood glucose HbAIc, were significantly increased in diabetic group when compared with control group [P<0.001]. Also microalbuminuria in urine as AER was significantly increased when compared with the control group [P< 0.001]. An increased serum sialic acid concentration is found to be predictive for the onset of microalbuminuria. There was a significantly positive correlation between total serum sialic acid, microalbuminuria and fasting blood glucose in the diabetic group. There was highly significant positive correlation between the mean value of sialic acid and albumin / creatinine ratio in group II and III diabetic children. Early detection of diabetic children who are prone to develop diabetic nephropathy is of utmost clinical importance and raised serum sialic acid could be used as a useful biochemical marker for early detection of diabetic nephropathy in children

Glycoconjugate profile in plasma and erythrocytes of gastric cancer patients.

The present study has examined the glycoconjugate profile in plasma and erythrocyte membranes of 24 adult male gastric cancer patients and an equal number of age and sex-matched controls. Protein-bound hexose, hexosamine and sialic acid were significantly increased in plasma and erythrocytes of gastric cancer patients compared to controls. Elevation of glycoconjugates in circulation is suggested to be a result of increased shedding by the tumor cells or increased synthesis by liver, due to acute phase response.

Importance of glycoproteins in human cancer.

Usefulness of cell surface glycoprotein components as markers in early detection of cancer and in monitoring progress during treatment has been evaluated. Total sialic acid (TSA), lipid bound sialic acid (LSA) and seromucoid fractions (SF) have been compared in the sera of healthy human volunteers and patients at different stages of diagnosis and treatment of leukemia, cancer of breast, cervix, and oral cavity. The levels of TSA, LSA and SF are found to be increased in cancer and is proportionate with malignancy. Their levels show decline in patients who respond well to treatment and show increase in patients with recurrence of cancer even before any clinical evidence of recurrence is available. Changes have also been noted in the glycoprotein fractions and their ratios.

Administration of the plasticizer di (2-ethylhexyl) phthalate alters glycoconjugate profile.

This study was undertaken to evaluate the level of glycoproteins and sialic acid in rats fed di (2-ethylhexyl)-phthalate (DEHP) in the diet for 24 weeks. Protein-bound hexose, hexosamine and sialic acid were increased in plasma and liver of rats treated with DEHP, whereas the erythrocyte membrane showed a reduction following DEHP administration. Evaluation of glycoproteins is a useful indicator of the carcinogenic process. It is suggested that profound alterations in membrane components observed in the present study may be related to the carcinogenic potential of DEHP.

Serum beta-N-acetylhexosaminidase, carcinoembryonic antigen & sialic acid in benign & malignant extrahepatic biliary obstruction.

Study of tumour markers to differentiate benign and malignant extra hepatic biliary obstructions showed that levels fo serum beta-N-acetylhexosaminidase and lipid associated sialic acid were not different in the two groups. The levels of carcinoembryonic antigen (CEA) and total sialic acid (TSA), on the other hand, were significantly higher in patients with the malignant biliary obstruction. At a cut-off value of 6.4 ng/ml (mean + 2SD) CEA had 66.7 per cent true positivity in malignancy 100 per cent true negativity in control and 78 per cent true negativity in the benign group. Similarly, TSA at a cut off value of 60 mg/dl had 61 per cent true positivity in malignancy, 90 per cent true negativity in controls and 70 per cent true negativity in the benign group. These two tumour markers appear to have similar diagnostic potential for malignant extrahepatic biliary obstruction. Surgical management of the malignant obstruction did not result in a decline in the elevated levels of these two markers during the post-surgical period of 7 days.

Serum sialic acid--an important cancer marker.

Total serum sialic acid (TSA), Lipid associated sialic acid (LASA), Total protein (TP) and TSA/TP factor (as cancer markers) have been estimated in 78 patients of cancer stomach, breast, colorectal region and gall bladder, before and after treatment and of varying degrees of metastasis and compared to 30 healthy controls. A significant rise in TSA and TSA/TP factor and a decrease in serum total protein levels was found in all cases of cancer. This increase was directly proportional to the degree of metastasis i.e. tumour burden. Serum TP levels were found decreased in all patients. Rise in LASA levels was not significant. Raised TSA/TP levels became lower to certain extent after effective therapy. Hence it can be inferred that although TSA and TSA/TP are not specific they are however, sensitive markers regarding detection of malignancy and useful in monitoring cancer progression and/or recurrent while evaluating the efficacy of various cancer therapies.

Serum alkaline phosphatase: its isoenzymes, 5-nucleotidase and sialic acid in normal and abnormal pregnancies

Alkaline phosphatase [ALP] enzyme activity and its isoenzymes were determined in serum by heat inactivation and chemical inhibition by urea, L-phenylalanine and EDTA. Sialic acid concentration and 5- nucleotidase [5-NT] activity were also measured in serum of 381 consecutive pregnant cases seen in the obstetric outpatient clinic and Ward of Jordan University Hospital. These included normal pregnancies and pregnancies associated with other conditions such as toxemias, diabetes mellitus, and also abortion cases. This study was undertaken, to assess the activity of ALP and its isoenzymes in normal and abnormal pregnancies with a view to evaluate their usefulness as parameters of placental function. The changes in the concentration of serum sialic acid and 5-NT activity in all subjects were also studied. The cases in study were divided into three groups [trimesters]. The results from this study showed a gradual increase in placental ALP isoenzymes which reaches a maximum at term. A definite enzyme pattern of ALP was seen in normal and abnormal pregnancies and inhibition by EDTA is a valuable index for the placental function. Serum 5-NT activity did not change between the first and the third trimesters of pregnancy. However there is a gradual and significant increase in the mean [ +/- SD] serum sialic acid concentration with progressing pregnancy

Cerebrospinal fluid N-acetyl neuraminic acid estimation for early diagnosis and differentiation of bacterial meningitis.

Cerebrospinal fluid (CSF) analysis for free, bound and total N-Acetyl Neuraminic Acid (NANA) as well as serum NANA was done in 68 patients of bacterial meningitis, of which 37 cases were of pyrogenic meningitis and 31 of tuberculous meningitis. Ten patients were included in the control group. The free NANA levels were increased in only pyogenic meningitis, independent of protein levels but the bound form increased with the increase in CSF proteins. The increase of free NANA in CSF of pyogenic meningitis patients was not related to the cell count or sugar content in CSF or to the duration or severity of illness. This finding can be of great help in differentiating cases of pyogenic meningitis, particularly partially treated patients, who may have ambiguous pictures of CSF analysis, from the cases of tuberculous meningitis.

Serum sialic acid levels in healthy individuals.

Serum sialic acid values, estimated by thiobarbituric acid method of Warren as modified by Saifer and Gerstenfeld in 50 normal healthy persons of both sexes are reported. The average values were 68.47 +/- 4.85 mg% and 67.77 +/- 7.87 mg% for males and females respectively and for both sexes the value was 68.12 +/- 6.70 mg%. Age and sex have no influence on sialic acid levels in serum.

Serum total sialic acid and regan isoenzyme levels in patients with lung cancer.

Serum total sialic acid (TSA), Regan isoenzyme (RI) (heat stable placenta like alkaline phosphatase) and TSA/Total protein (TP) ratio were estimated in 44 cases of Lung cancer using highly specific chemical methods to assess their efficacy as malignancy markers. Levels of the two markers were compared with 27 matched healthy controls. A significant increase (P less than 0.001) in both the bio-markers were compared with 27 matched healthy controls. A significant increase (P less than 0.001) in both the bio-markers was observed compared to controls. TSA/TP ratio was significantly higher (P less than 0.001) in lung cancer patients compared to controls. TSA levels were elevated in more cases of patients compared to elevations in RI. Mean values of TSA and RI were higher in epidermoid carcinoma than adeno carcinoma. The use of combination of these markers may be considered in the diagnosis of the disease in future trials.

Increased levels of serum sialic acid in the sera of cancer patients

Sialic acid concentration in the sera of patients with cancers of various organs including breast, lung, intestine, cervix and pharynx was determined and compared with their normal counter parts. Although serum sialic acid levels were found to be higher than normal in all types studied, the difference was more pronounced in breast and lung cancers, where mean Values were 4.7 +/- 0.079 mM and 4.4 +/- 1.01 mM respectively against a mean value of 2.17 +/- 0.495 mM estimated in normal individuals

Cuantificación de acido sialico, l-fucosa y fucosidasa séricos en la pesquisa de cáncer gástrico / Quantification of serum sialic acid l-fucose and fucosidase in the detection of gastric cancer

Con el propósito de conocer los niveles séricos de ácido siálico, 1-fucosa y fucosidasa, se cuantificaron sus valores en 107 adultos (25 a 90 años) sometidos a endoscopia oral. Con los resultados obtenidos se analiza su utilidad como método de pesquisa en el diagnóstico de cáncer gástrico. La muestra estudiada estuvo integrada por cuatro grupos: sin alteraciones endoscópicas (n=25); úlcera duodenal (n = 25); úlcera gástrica (n = 25) y cáncer gástrico (n = 32). Los valores promedio obtenidos para el ácido siálico fueron: 1,96; 1,19; 20,5 y 2,80 micronmol/ml; para la 1-fucosa: 9,32; 9,00; 10,8 y 13,0 mg/dl y para la actividad fucosidasa: 11,5; 10,2; 9,06 y 10,6 U/l respectivamente. El coeficiente de correlación ácido siálico-1-fucosa fue 0,80 (p < 0,01) en los grupos sin alteración y cáncer gástrico. La fucosidasa no tuvo variaciones significativas entre los diferentes grupos estudiados. Las determinaçöes de ácido siálico y 1-fucosa presentaron una sensibilidad del 81 y 74% respectivamente en pacientes portadores de cáncer gástrico pero ella fue de 97% cuando se consideran pacientes que tienen ácido siálico o 1-fucosa positivos. Porcentajes importantes de pacientes sin alteraciones endoscópicas o con otras afecciones gástricas cursan con valores positivos de ácido siálico y 1-fucosa. Por tratarse de procedimientos simples y sensibles, las ácido siálico y 1-fucosa. Por tratarse de procedimientos simpsles y sensibles, las determinaciones séricas de ácido siálico y 1-fucosa pudiera ser de utilidad para la detección de cáncer gástrico o de su control evolutivo