Studies on serum and urinary sialic acid in glomerulonephritis and nephrosis

I. Serum sialic acid

Abstract

To find the clinical meanings of serum sialic acid (SA) in glomerulonephritis and nephrosis, it was estimated in 94 patients with diffuse glomerulonephritis, in 8 patients with nephrosis, in patients with other diseases and in healthy subjects and its relationships to the clinical andd pathohistological findings were studied. The method used was the Ehrlich's direct reaction using p-dimethylaminobenzaldehyde reported by Werner and Odin. Results were as follow: 1) Normal level of serum SA ranges from 32.5 to 71.0 mg/100ml with a mean of 52.7 mg/ 100ml. In the patients with rheumatism, tuberculous pleurisy, cancer, inflammations, nephrosis, glomerulonephritis and hypertension, SA levels were significantly elevated, whereas in liver cirrhosis they were lower. 2) In glomerulonephritis, in general, serum SA was higher than normal at its initial stage, once decreased towards 10 days after the onset of the disease, and gradually elevated again from one month after the onset to a second peak situating about 3rd month which was followed by a declining to normal level at 4-6th month. On an average, SA level was highest (68.3 mg/100ml) in subacute stage, in acute and chronic stage being somewhat lower (64.9 mg/100ml, and 61.8 mg/ 1OOml, respectively). 3) The first peak of this trend of serum SA level in glomerulonephritis is supposed to be associated with the preceding infection, the second with repair of renal tissues. 4) Roughly saying, serum SA levels were generally higher in the cases with severe histolic renal damages, especially in subacute stage. 5) Considering from the feature of serum SA and histological and clinical findings, acute and excerbated glomerulonephritis should be regarded active and be managed as such for 6 months at least. 6) Markedly elevated levels of SA were found in 8 cases of lipoidnephrosis with a mean of 82.3mg/100ml. They were especially higher when edema and marked albuminuria existed. 7) In 45 hypertensive patients, too, serum SA levels were significantly higher than normal (mean 62.Omg/1OOml), especially so in patients with albuminuria. 8) In general, serum SA level was higher with the impairment of renal functions. 9) In glomerulonephritis, serum SA level ran almost parallel with blood sedimentation rate, but the former was more sensitively correlated to the clinical course. Anti-streptolysine-O titer was also in parallel to SA level in rheumatism, but in glomerulonephritis the curves crossed each other. 10) There were significant positive correlations between serum SA level and blood pressure in glomerulonephritis and hypertension. 11) In inflammatic diseases the serum SA tends to decrease in convalescence.