Search

Urinary trisaccharides containing sialic acid, urinary total sialic acid, and serum sialic acid were studied in 51 patients with rheumatoid arthritis (RA). The urinary excretion of sialyllactose and sialyl-N-acetyllactosamine was measured by quantitative gas chromatography. The output of sialyllactose was significantly greater in patients with RA (31.9 +/- 17.3 mg/24, SD) than in control subjects (15.9 +/- 5.4, P less than 0.001). The RA patients also had higher mean levels of urinary sialyl-N-acetyllactosamine (P less than 0.05), total urinary sialic acid (P less than 0.001), and serum sialic acid (P less than 0.001). Urinary excretion of sialyllactose was considerably higher in patients with active and aggressive RA and moderately higher in patients with moderate disease activity. Excretion in those with mild or almost inactive RA did not differ significantly from that in the controls. Linear regression analysis revealed a strong positive correlation between urinary sialyllactose levels and clinical disease activity (P less than 0.001), as well as between excretion of sialyllactose and sialyl-N-acetyllactosamine in RA. These results suggest that the urinary content of trisaccharides containing sialic acid is an indicator of disease activity of RA.

In protein-calorie malnourished children, with or without associated vitamin A deficiency, skin content of acid mucopolysaccharides (MPS) and urinary excretion of MPS and amino sugars were studied. MPS content of skin in both malnourished groups was increased 3-6-fold. This increase was essentially in the non-sulphated component. In normal skin, non-sulphate MPS accounted for 68% of the MPS content, whereas in the malnourished group with vitamin A deficiency it constituted 93%. Urinary excretion of MPS (24h) was significantly reduced by 50-70% in malnourished groups. This returned to normal levels in the malnourished/vitamin A deficient group when vitamin A injections were administered. Excretion of amino sugars (24 h) in the malnourished groups was also decreased by 50-70%. In normal children 55% of the total amino sugars was dialysable whereas in the malnourished it was increased to 60%. The excretion of protein-bound and dialysable amino sugars was increased to normal level only in the group given supplements of vitamin A in addition of protein and calories.

Urinary sialic acid-containing trisaccharides, total sialic acid, and serum sialic acid were studied in 17 patients with systemic lupus erythematosus (SLE) and in 15 healthy controls. The urinary excretion of sialyllactose, measured by a gas chromatographic method, was significantly greater in patients with SLE (37.4 +/- 21.4 mg/24 hours, SD) than in the control subjects (13.7 +/- 3.8 mg/24 hours, p less than 0.001). The mean excretion of sialyl-N-acetyllactosamine (16.6 +/- 8.5 mg/24 hours) and total sialic acid (82.5 +/- 29.4 mg/24 hours) was also greater in the SLE group than in the controls (8.7 +/- 2.8 and 58.0 +/- 16.0 mg/24 hours, respectively; p less than 0.01). Serum levels of sialic acid were correspondingly higher in the SLE patients (84.4 +/- 20.4 mg/100 ml) than in the controls (63.7 +/- 6.5 mg/100 ml, p less than 0.001). Urinary excretion of sialyl-lactose correlated positively with clinical disease activity (p less than 0.001) and with anti-DNA antibody levels (p less than 0.05). On the average, patients with moderate or severe disease excreted three times more sialyl-lactose than did those with mild or inactive disease. Our results suggest that the excretion of sialyl-oligosaccharides reflects disease activity in SLE.