Increase In Sialic Acid Concentration Research Articles

Influence of Ophthalmic Solutions on Tear Components.

Tear fluids are a mixture of secretions derived from lacrimal glands, accessory lacrimal glands, conjunctiva, and meibomian glands. Compositional changes to tears occur in the normal state and during ocular surface disease, such as dry eye conditions. We have investigated compositional changes to tears after topical application of ophthalmic solutions, with regard to tear-specific proteins (secretory immunoglobulin A, lactoferrin, lipocalin-1, and lysozyme) and ocular surface mucin in normal and dry eye conditions using high-performance liquid chromatography. After application of saline solution (0.9% sodium chloride) in normal subjects, transient but significant decreases in all tear components were observed. The recovery of protein concentrations took up to 30 minutes and lasted longer when the saline solution was applied more frequently. When applying ophthalmic solutions, a balance between washout and dilutional effects should be considered in addition to the therapeutic effect. Investigation of the effect of diquafosol solution (3%) in normal subjects revealed a significant increase in sialic acid concentration, a marker of ocular mucin, at 5 minutes after application, whereas a significant decrease was observed with saline. This result indicates the accelerated secretion of mucin from ocular tissues induced by diquafosol. A clinical study to determine the efficacy of diquafosol in patients with dry eye revealed improvements in tear breakup time, keratoconjunctival staining scores, and Schirmer test score, accompanied by an increase in sialic acid concentration in tears. Investigating normal and dry eye conditions through tear analysis may clarify the pathophysiology of dry eye conditions and support the efficacy of treatments.

Symptome und Diagnostik innerer Krankheiten

The possible physiological role of estrogen in the epididymis and ventral prostate of rat was investigated. In prepubertal rats castrated for 7 days, treatment with estradiol (1.0 micrograms) for 7 days (35-day-old at autopsy) resulted in a marked increase in the weight and content of glyceryl-phosphorylcholine and sialic acid in the epididymis; estradiol and dihydrotestosterone were equipotent in causing an increase in sialic acid concentration. Estradiol showed a synergistic effect in influencing the androgen action on the growth of the prepubertal rat prostate while no such synergism was evident in stimulating the secretory function of the epididymis. The duality of epididymal response to the two sex steroids suggests that the two hormones may be acting in concert at physiological levels as regulators of epididymal secretory function; the need for identifying estrogen specific biochemical indices in the epididymis is discussed.

Serum sialic acid changes in non-insulin-dependant diabetes mellitus (NIDDM) patients following bitter melon (Momordica charantia) and rosiglitazone (Avandia) treatment

Diabetes mellitus is associated with an increase in sialic acid concentration along with other complications. Sialic acid changes in NIDDM patients were investigated following bitter melon (55 ml/24h) and rosiglitazone (4 mg/24h) treatment. A total of 25 patients of both sexes were used in each experimental group. Patients following bitter melon treatment showed no significant difference of serum sialic acid (57.95+/-4.90 vs. 57.6+/-5.56 mg/dl, p=0.17) and serum glucose concentration (93.7+/-9.63 vs. 88.35+/-6.31 mg/dl, p=0.78) as compared to control subjects. However, the concentration of total cholesterol was significantly high in these patients as compared to control subjects (192+/-14.23 vs. 170.6+/-15.1mg/dl, p<0.03) but within normal range (160-200mg/dl), suggesting the significant hypoglycemic and lipid-lowering properties of bitter melon. The patients following rosiglitazone treatment showed a significant increase of serum sialic acid concentration (60.2+/-5.80 vs. 57.6+/-5.56 mg/dl, p=0.01) along with glucose (112+/-6.2 vs. 88.35+/-6.31 mg/dl, p<0.04) and total cholesterol concentration (216.45+/-20.2 vs. 170.6+/-15.1mg/dl, p<0.01) as compared to control subjects. In addition six of the patients had retinopathy, two of whom were suffering also from myocardial infarction and they still had a higher serum sialic acid (61.05+/-1.20mg/dl), glucose (187+/-2.11 mg/dl), total cholesterol (239.10+/-5.04 mg/dl) and triglyceride (183+/-4.14 mg/dl) concentration, indicating a poor response of these patients to rosiglitazone. Comparison of serum sialic acid concentration of patients, following bitter melon and rosiglitazone treatment revealed no significant difference but the study showed that bitter melon could be more effective in the management of diabetes and its related complications as compared to rosiglitazone.

Raised Serum Sialic Acid Concentration Precedes Onset of Microalbuminuria in IDDM: A 10-year follow-up study

Elevated concentrations of serum sialic acid, a potent cardiovascular risk factor in the general population, have been found in patients with IDDM and microalbuminuria. We investigated whether a coincidence exists between the increase of sialic acid concentrations and albuminuria in the transition from normoalbuminuria to microalbuminuria. Furthermore, the predictability of increased sialic acid as well as von Willebrand factor (vWF) and total and HDL cholesterol concentrations in development of persistent microalbuminuria in IDDM was investigated. This 10-year prospective study was carried out in a cohort of 209 IDDM patients with normoalbuminuria at baseline. Of the cohort, 198 patients completed the follow-up period and 27 developed persistent microalbuminuria (urinary albumin excretion rate [UAER] > or = 30 mg/24 h). A coincident increase of UAER and serum sialic acid concentration was seen before persistent microalbuminuria was diagnosed. Elevation of serum sialic acid concentrations in those who later developed microalbuminuria occurred 3 years before the diagnosis of persistent microalbuminuria. Baseline serum sialic acid concentrations were significantly higher in the group of patients who later developed microalbuminuria than in the group who remained normoalbuminuric (2.02 +/- 0.41 vs. 1.85 +/- 0.31 mmol/l [means +/- SD], P < 0.05). Baseline serum sialic acid concentration correlated significantly with HbA1c, UAER, blood pressure, total cholesterol, HDL cholesterol, and vWF and was significantly predictive for development of microalbuminuria (hazards ratio [95% CI], 3.1 [1.2-8.1]; P = 0.02) after adjustments for sex, duration of diabetes, smoking, blood pressure, vWF, total cholesterol, and HDL cholesterol. Adjustment for the effects of HbA1c and UAER, however, canceled out the predictive effect of serum sialic acid. UAER and serum sialic acid concentration increase coincidentally before the onset of persistent microalbuminuria. An increased serum sialic acid concentration is predictive for the onset of microalbuminuria independent of age, sex, diabetes duration, smoking, blood pressure, vWF, and total HDL cholesterol.

Sialic acid concentrations before and after treatment of ocular tumors

Sialic acid or N-acetyl neuraminic acid (NANA) constitutes the terminal residue of carbohydrate chains of glycoprotein and glycolipid originating from membrane cells and serum. Biochemical studies indicate an increase of glycoprotein and glycolipid content of cells that have gone through a transformation. In the authors' 1987 study in FKUI-RSCM· an increase of sialic acid concentration was found in eye tumor patients. This figure was statistically significant compared to normal people. From this previous study the authors tried to use sialic acid as a means of monitoring the results of therapy. They used the Chatagnon & Chatagnon method to measure sialic acid concentrations.In spite of the inability to show the potential of sialic acid as a means of monitoring results of therapy, this study might be continued by inciuding more samples and looking more closely at this method of measurement.

Disturbance of sialic acid metabolism by chronic cadmium exposure and its relation to proteinuria

In workers exposed to Cd (8 years on the average), we have found a significant decrease of sialic acid in erythrocyte membranes (22.61 ± 1.84 vs 25.80 ± 3.01 μg/mg of protein in controls, p < 0.05) and an increase of sialic acid concentration in both urine (276.7 ± 132.3 vs 174.5 ± 70.9 μg/g of creatinine, p < 0.05) and plasma (761.8 ± 83.5 vs 640.4 ± 70.7 μg/ml, p < 0.01). In rats exposed to Cd (100 ppm in drinking water for 5.5 months), we have observed a reduction of the sialic acid level in erythrocyte membranes (31.4 ± 1.2 vs 33.4 ± 1.1 μg/mg of protein, p < 0.01) and glomeruli (12.5 ± 1.3 vs 13.9 ± 1.6 μg/mg of protein, p < 0.05). These effects in Cd treated rats were accompanied by a loss of the glomerular barrier selectivity as reflected by an increased urinary output of albumin and transferrin. After 10 months of Cd exposure, the albuminuria and transferrinuria were negatively correlated with sialic acid content of glomerular membranes ( r = −0.47 and −0.51, p < 0.05), which suggests that the depletion of sialic acid is involved in the loss of glomerular barrier function induced by long term Cd exposure. In Cd-treated rats, sialidase activity was enhanced in kidney cortex and in serum but not in glomeruli.