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Background: In this study, children with phenylketonuria and healthy control subjects were assessed for glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT) activity, malondialdehyde (MDA), glutathione (GSH), retinol, cholecalciferol, α-tocopherol, phylloquinone, total sialic acid (TSA), lipid bound sialic acid (LSA), total antioxidant (TAS), total oxidation (TOS), and amino acid levels, and the relationships of these variables with phenylketonuria were evaluated., Methods: The study included 60 children with phenylketonuria and 30 control subjects. Children with phenylketonuria were divided into hyperphenylalaninemia (HPA) and amino acid mixture (AAM) groups., Results: The HPA group had significantly lower levels of GSH-Px, CAT, GSH, TAS, α-aminobutyric acid, and taurine levels (p < 0.01, p < 0.05, p < 0.05, p < 0.001, p < 0.01, p < 0.05, respectively) than the control group. Additionally, the AAM group had significantly lower levels of CAT, TAS, and phylloquinones (p < 0.05, p < 0.05, p < 0.05, respectively) than the control group. It was observed in our study that in the HPA group, a significantly strong positive linear correlation was observed between phenylalanine and α-aminoadipic acid (r = 0.777; p = 0.002)., Conclusions: It was concluded that the levels of α-aminoadipic acid and phylloquinone might be an appropriate choice for the determination of phenylketonuria in parallel with the levels of phenylalanine. α-aminobutyric acid and phylloquinone as a supplement can decrease HPA damage.

Background: Raised levels of cholesterol and triglycerides are major risk factors for atherosclerosis, which can lead to coronary heart disease. Both the CRP and Sialic Acid levels are elevated in response to acute as well as chronic inflammatory conditions. This study was conducted to determine the serum lipid profile, CRP and Sialic Acid levels and their relationship with each other in healthy individuals., Methods: This was a cross-sectional study performed by the Department of Biochemistry, Institute of Basic Medical Sciences (IBMS), Khyber Medical University (KMU) Peshawar. Two hundred healthy subjects in the age group of 18-50 years of either gender was recruited through consecutive sampling. Blood sampling were taken from all the participants and analysed each for serum lipid profile, CRP and Sialic Acid levels through standardized methods., Results: A total of 200 individuals were included, 53.5% being male. Mean age was 33.39±9.76 years. Mean height was 167.86±10.8 cm. Mean weight was 66.87±11.39kg. Mean Hip-Waist ratio was 0.93±0.16 whereas mean BMI was 24.12±3.65. The simultaneous raised levels of serum lipids, CRP and Sialic Acid were observed more commonly in females as compared to males. CRP and Sialic Acid has got statistically significant correlation with HDL. Sialic Acid had statistically significant correlation with triglycerides in the study population with a significant p-value (<0.05), while having a non-significant correlation with total cholesterol and LDL. CRP had got significant correlation with total cholesterol and LDL and non-significant correlation with triglycerides., Conclusions: The study showed that serum CRP and Sialic Acid had a significant negative correlation with serum HDL. A significant positive correlation was found between serum Sialic Acid and triglycerides. CRP and Sialic Acid though expensive but are useful predictors of atherosclerotic disease.

Background: We investigated the relationship between serum levels of total sialic acid, lipid bound sialic acid and acute pancreatitis in a rat model of a common bile duct ligation induced acute pancreatitis., Methods: Twenty five Sprague-Dawley male rats weighing 250-300 g were divided into two groups (n=10: control, n=15: experimental). In the control group only a sham laparotomy was performed. In the experimental group, acute pancreatitis was induced by common pancreatobiliary tract ligation. After 36 hours the rats were killed and amylase, serum total sialic acid, lipid bound sialic acid and lipid profiles were measured. Histopathological confirmation of acute pancreatitis was done using hematoxylin and eosin staining., Results: Mean amylase, total sialic acid (TSA) and lipid bound sialic acid (LBSA) measurements in the experimental group were significantly higher than in the control group. There was no significant difference in the lipid profiles between the two groups., Conclusion: Increased levels of TSA and LBSA can be useful as specific markers in the diagnosis of acute pancreatitis independent of serum lipid profile., (Celsius.)

Objective: There are evidences that the changes in glycosylation and sialylation of proteins and lipids play an important role in the pathogenesis and progression of various liver diseases. The aim of this study was to evaluate the changes in the sialylation of serum lipids measured by the level of lipid-bound sialic acid (LSA) in liver diseases of different etiologies., Materials and Methods: Tested group consisted of 303 patients suffering from liver diseases: alcoholic and non-alcoholic cirrhosis, chronic non-viral hepatitis, toxic hepatitis, chronic viral C and B hepatitis, autoimmune hepatitis, primary liver cancer, liver cancer and cirrhosis (mixed group), acute hepatitis B, primary biliary cirrhosis and fatty liver. LSA was determined by the method of Katopodis and co-workers., Results: There were significant differences in the serum LSA concentrations between liver diseases of different etiologies. The level of LSA in liver tumors was higher than that in both types of cirrhosis: alcoholic and non-alcoholic. In turn, LSA level in non-alcoholic cirrhosis was lower than in toxic hepatitis and mixed group. There was no difference in LSA concentration between tumor and mixed group. Similarly to LSA, AFP level in tumor group was also higher than that in both cirrhotic groups, but there was no difference in AFP concentration between tumor and mixed group., Conclusions: The sialylation of serum lipids alters in liver diseases of different etiologies. Given the importance of glycans in biological systems we can speculate that the changes in lipids sialylation play an important role in liver pathology, especially in primary cancer, cirrhosis and toxic hepatitis.

Serum total sialic acid (TSA) concentration is a sensitive marker of excessive alcohol consumption and is the sum of protein-bound sialic acid, lipid-bound sialic acid (LSA), and free sialic acid. The LSA is the fraction of SA attached to gangliosides that are transported in the blood by the lipoproteins. In this article, the effect of chronic alcohol consumption on the serum levels of LSA was evaluated. The objective of the study was to understand the mechanism of elevated serum TSA concentration during alcohol abuse. Additionally, the association of LSA with serum lipid profile was tested. For this purpose, the levels of LSA, TSA, lipids, lipoproteins, and apolipoproteins (apos) in the sera of 106 alcoholics were measured. The serum level of LSA in alcohol abusers was significantly elevated. This increase was because of the elevated level of LSA in patients drinking alcohol up to 2 days before sampling. The elevated level of LSA positively correlated with TSA, and also with biochemical indices of hepatocellular injury such as aspartate aminotransferase and gamma-glutamyltransferase, but did not correlate with any lipids, apos, and lipoproteins. The increase in LSA level is not related with the status of serum lipid profile but is related to the liver status estimated by the biochemical markers of liver cell damage. On the basis of our results, we conclude that the elevated level of LSA in alcohol abusers contributes to an increase in the serum concentration of TSA, and contrary to TSA, is affected by the status of liver cells., (2010 Elsevier Inc. All rights reserved.)

Objectives: To investigate and discuss the total-, lipid-associated, and thrombocyte-sialic acid levels in chronic heart failure (CHF) patients., Design and Methods: Thirty-one chronic heart failure patients and 38 healthy controls were included in the study. Serum total sialic acid (TSA), lipid associated sialic acid (LASA), thrombocyte sialic acid (TrSA) were determined together with the traditional inflammation and prognostic markers., Results: Serum TSA levels were significantly higher in patient group (3.08 + or - 0.33 mmol/L) than control group (2.60 + or - 0.17 mmol/L). Serum LASA, homocysteine, high-sensitivity CRP, brain natriuretic peptide and erythrocyte sedimentation rate were also significantly higher in patient group. TrSA levels were not significant between the groups., Conclusion: TSA and LASA levels increase in CHF, independent from coronary artery disease. TrSA levels were not found to be a prognostic or valuable marker for CHF patients. Acute phase response and lipid associated portions of SA are thought to be responsible for SA rise in CHF., (Copyright 2009 The Canadian Society of Clinical Chemists. All rights reserved.)

Cancer patients are found to have elevated serum levels of lipid-associated sialic acid (LASA). LASA measurement provides a valuable test for the diagnosis of human cancer. The currently used measurement methods are tedious and nonselective. Here we report a method based on immobilized enzyme minicolumns in a flow system for the analysis of this clinically important analyte. Three enzymes comprising two minicolumns are introduced online and the analyte in a precisely injected volume of 20 microL is made to pass through these immobilized enzyme columns. The final product of the reaction is detected amperometrically. Neuraminidase and NANA-aldolase are coimmobilized on controlled pore glass, followed by a column of pyruvate oxidase. The method was applied to the quantitation of LASA in the sera of normal individuals and patients with cancer of the esophagus. We observed no loss of activity of the immobilized enzymes after analyzing about 300 samples. The sample throughput was 30 samples per hour.

The aim of this study was to investigate the possible relationship between serum total sialic acid (TSA) concentration, recently shown to be a cardiovascular risk factor, and lipid and protein oxidation and antioxidant status and the severity of coronary artery disease (CAD) according to the obstructive vessel number in patients. The study was carried out on a total of 200 patients (142 men and 58 women) who were hospitalized for elective coronary angiographic evaluation with complaint of typical angina pectoris. According to the results of angiography, 150 patients had angiographically proven CAD (CAD group) and 50 patients had a history suggestive of angina pectoris but normal coronary angiograms (control group). The CAD group was further divided into single-, double- and triple-vessel disease groups according to the number of vessels involved. Lipid parameters were determined by routine laboratory methods. Plasma malondialdehyde (MDA) and vitamin E concentrations were determined by high-performance liquid chromatography. TSA and other oxidant and antioxidant parameters were studied spectrophotometrically. Our results demonstrated significant increases both in TSA levels and in indicators of oxidative stress in the patients with CAD compared with the controls. However, antioxidant parameters were decreased in the patients with CAD. We found strong positive correlations between TSA and plasma MDA, Delta-MDA which represents the degree of oxidative modification of apolipoprotein B-containing lipoproteins, serum protein carbonyls and apolipoprotein B and weak correlations between TSA and low density lipoprotein cholesterol, triacylglycerol, paraoxonase, glutathione peroxidase (GPx), vitamin C and vitamin E. In conclusion, TSA is related to markers of lipid and protein oxidation, paraoxonase and GPx activities, vitamin C and E levels and the severity of CAD.

Elevated serum sialic acid concentration is a risk factor for coronary heart disease in general population along with dyslipidemia. Sialic acid and lipid profile was determined in healthy subjects (Group A1 and A2) and sixty cardiac patients, divided into two groups, group B comprising of thirty male patients and group C comprising of thirty female patients. A highly significant increase was observed in the level of sialic acid and different variables of lipid profile except HDL-C in all patients. HDL-C showed a significant decrease in patients. An increase in the level of sialic acid in cardiac patients showing the implications of raised level of sialic acid in the development of cardiovascular complications.

The aim of the present study was to investigate the serum total protein (TP), total sialic acid (TSA), lipid-associated sialic acid (LSA), LSA/TP, and LSA/TP values in type 2 diabetes mellitus (DM) patients. Two study groups (healthy controls and type 2 DM subjects) were examined. For the type 2 DM group, 120 patients (60 females and 60 males) who had been diagnosed and treated for type 2 DM in the Yuzuncu Yil University Hospital, Van, Turkey, were selected consecutively. Forty healthy individuals (20 females and 20 males) were selected from hospital staff and other outpatient clinics to serve as the control group. They were matched for age, sex, body mass index, and smoking status. None of the participants had taken vitamin or mineral supplements for at least 2 weeks before sampling. To determine serum glucose, TP, TSA, and LSA levels, blood samples were drawn after all of the subjects fasted overnight. It was found that diabetics had higher TSA, LSA, TSA/TP, and LSA/TP levels than controls. However, the TP levels were not significantly different between the groups. Our results showed that TSA, LSA, TSA/TP, and LSA/TP have interactive connections with DM. These parameters can be used as a diagnostic index for patients with DM., (Copyright 2003 Wiley-Liss, Inc.)

Objective: Sialic acid, a terminal component of glycoproteins and glycolipids, is found to be elevated in many pathologic conditions, including preterm deliveries and uterine dysfunction. Along with increased lipid peroxides, it is one of the indices of oxidative stress seen in recurrent abortion. This article investigates whether changes in plasma total sialic acid (TSA) and lipid-bound sialic acid (LSA) contribute to this condition., Patients and Methods: Plasma samples of 25 nonpregnant (NP) healthy women, 25 normotensive pregnant women (NTP), and 120 women with recurrent abortion (RA) were assayed for TSA, LSA, total protein (TP), and TSA/TP. Recurrent aborters were divided into four subgroups according to etiology: 25 autoimmune (AUTO), 25 luteal phase defect (LPD), 20 anatomical defect (AD), and 50 with unexplained etiology (UNEx)., Results: Plasma TSA and LSA levels were significantly elevated in AUTO aborters in comparison with controls (NP and NTP) and other recurrent abortion subgroups. TSA/TP value was significantly increased in abortion with immunological and unexplained etiology (AUTO and UNEx)., Conclusions: According to our results we can suggest that elevation of TSA and LSA is indeed a reflection of the immunologic abnormalities in the AUTO group, and that TSA and LSA increase is secondary to the underlying disease of AUTO aborters.

Background: Inflammation of the arterial wall has emerged to be an important contributor to the process of atherosclerosis, the major cause of coronary heart disease. Several factors are currently under investigation as inflammatory markers of atherosclerosis. Serum sialic acid and matrix metalloproteinase-9 may provide such markers. We studied their association with the lipid profile and with the inflammatory markers C-reactive protein and leukocyte count in a clinically healthy population of men., Materials and Methods: Cardiovascular risk-related laboratory tests were carried out in 65 consecutive male employees in connection with an occupational health survey in 1996. The subjects were divided into tertiles on the basis of serum sialic acid or matrix metalloproteinase-9 concentration., Results: In a stepwise polychotomous logistic regression model adjusting for coronary heart disease risk factors, serum sialic acid concentration was not associated with markers of inflammation but rather with the lipid risk factors of atherosclerosis: inversely with HDL cholesterol (OR = 0.081, 95% CI 0.0068-0.97) and positively with total cholesterol (OR = 2.4, 95% CI 1-5.6). Matrix metalloproteinase-9 levels had a significant positive correlation with the leukocyte count (OR = 2.3, 95% CI 1.4-4)., Conclusions: Serum sialic acid does not appear to be an indicator of inflammation but is somehow connected with the level of total and HDL cholesterol. Serum matrix metalloproteinase-9 may provide a useful marker of inflammation because it correlates with the leukocyte count and is not associated with the lipid profile.

This study was carried out to examine the relationship between the charge on low density lipoproteins (LDLs) and lipid and clinical parameters in 104 asymptomatic dyslipidemic men and to identify biochemical and genetic factors that could contribute to the charge variability of LDL. LDL charge heterogeneity was evaluated by relative electrophoretic mobility (REM) on preformed 0.5% agarose gels and by chromatographic quantification of a minor electronegative LDL subfraction designated LDL(-). The mean REM value for LDL was 0.147+/-0.016 and the mean LDL(-) subfraction percentage was 5.6+/-2.8%. Both were positively correlated with common atherosclerotic risk factors, especially total cholesterol [for REM, r=0.27, P<0.005; for LDL(-), r=0.28, P=0.008] and LDL cholesterol [for REM, r=0.27, P=0.007; for LDL(-), r=0.26, P=0.01)] levels, and REM was positively correlated with triglycerides (r=0.27, P<0.005) and negatively with apoAI levels (r=-0.30, P<0.002). The variations in LDL charge were not due to oxidation, as measured by the lag phase and binding to the LDL receptor. The results of the 2 methods used to measure LDL charge were significantly correlated and had some identical characteristics (eg, association with LDL apoCIII content and plasma triglyceride levels in borderline and IIb dyslipidemic subjects); these methods reflect different specific features of LDL charge. The percentage of LDL(-) was correlated positively with the LDL sialic acid content (P<0.0001), whereas the REM was related to at least 2 distinct chromosomal loci. Multiple logistic analysis showed that individuals carrying minor alleles of BsrDI (P<0.05), apoCIII/SacI (P<0.01), as well as the frequent allele of XbaI (P<0.05) at the apoB and CIII gene loci had high REMs. This result suggests that LDL charge heterogeneity, which is positively correlated with the atherogenic lipid profile, is influenced by both genetic and biochemical factors.

1. Serum sialic acid is a reputed cardiovascular risk factor, but the reason why this is so is not clear. We therefore studied its relationship with other known cardiovascular risk factors (particularly those associated with insulin resistance) in 100 healthy young subjects (54 females and 46 males, age 20.7+/-0.89 years). 2. There was a significant univariate correlation between serum total sialic acid and fasting plasma insulin. Serum total sialic acid also correlated with fasting plasma glucose concentration and serum cholesterol and triacylglycerol. 3. In females there was a strong univariate correlation between serum total sialic acid and plasma fasting insulin and glucose concentrations, although in males there was a weaker univariate correlation between serum total sialic acid and fasting plasma glucose and the insulin resistance index. In addition, serum total sialic acid significantly correlated with systolic blood pressure, fasting serum cholesterol and triacylglycerol concentrations and body mass index in the females. In males serum total sialic acid significantly positively correlated with fasting serum cholesterol and triacylglycerol concentrations, and correlated inversely with the hip/waist ratio. 4. In multiple regression analysis of the 100 subjects serum total sialic acid correlated independently with fasting serum cholesterol, glucose and also plasma insulin concentrations. In females serum total sialic acid independently correlated with systolic and diastolic blood pressure, and serum cholesterol and fasting plasma glucose concentrations, although there was no significant independent correlation between serum total sialic acid and any of the other variables in the males.

Increased levels of sialic acid-containing glycoconjugates in serum have been observed in malignancies. In this study, significantly elevated serum concentrations of total sialic acid (TSA), TSA/total protein (TSA/TP) and lipid-bound sialic acid (LASA) were observed at diagnosis of children with various malignancies compared to healthy children. Serum TSA and TSA/TP were superior to LASA in differentiating solid tumors (p < 0.005) and leukemias (p < 0.05) from normal controls. In neuroblastoma and yolk sac tumors, a descending trend in TSA and TSA/TP was noted after successful treatment of the malignancy. Children with simultaneous malignancy and infection had significantly higher serum TSA (p < 0.05) and TSA/TP (p < 0.01) levels compared to patients with infectious diseases only, the corresponding areas under the curve were 0.83 and 0.88. The measurement of serum TSA and TSA/TP could be useful adjuncts in exclusion, diagnosis and follow-up of malignancies in children.

Total sialic acid (TSA), lipid-associated sialic acid (LASA), and fucose were estimated in sera of 35 patients with precancerous lesion of the oral cavity, 68 patients with cancer of the oral cavity, and 25 age- and sex-matched non-chewers of both tobacco and betal nut and nonsmokers as controls. Significant elevation in the serum levels of TSA and LASA were observed in patients with the precancerous and cancer lesions when compared with the controls. Serum TSA levels were elevated significantly in patients with cancer when compared with those with precancerous lesions. Circulating TSA and LASA levels were found to reflect tumor burden and correlated well with stage of the disease. However, serum fucose levels did not show an increase corresponding to stage of the disease. The results suggests that combined evaluation of these markers may be useful in predicting early malignant change and also in assessing the spread and invasiveness of the disease in cancer of the oral cavity.

Background: The early diagnosis of recurrent melanoma can contribute to better outcome if the disease can be surgically resected or if the metastases are responsive to systemic therapies. Lipid-associated sialic acid (LASA-P) and the S-100 protein (S-100) were evaluated as tumor markers for melanoma with the goal of early detection of recurrence., Methods: Sixty-seven patients were identified who had levels of S-100 and LASA-P drawn during their clinical course. A multivariate regression analysis was performed to determine the significance of the serum markers in relation to other prognostic factors for melanoma., Results: After a median follow-up of 30 months, 58 patients had recurrences, and 49 patients died of disease. LASA-P elevation was not associated with the time to recurrence (p = 0.2176) or survival (p = 0.2507). S-100 positivity was a significant predictor of recurrence (p < 0.0001) and survival (p = 0.0059). The median time to recurrence for S-100-positive and S-100-negative patients was 7.6 and 33.8 months, respectively. The median survival time was 59.2 months for S-100-negative patients and 29.6 months for patients positive for S-100., Conclusions: Serum S-100 shows significant correlations to both time to recurrence and survival and could be useful in the clinical detection of malignant melanoma.