Polyacrylamide Disc Electrophoresis of Cerebrospinal Fluid Proteins

Clinical Application

Abstract

The polyacrylamide disc electrophoresis technique has been applied to the fractionation of 386 samples of unconcentrated CSF obtained by atraumatic lumbar punctures, among which 122 fluids from 23 controls and 77 patients were categorized in this report. It was carried out by the method of Ornstein & Davis with these additional particulars. The gel tubes were 150.0mm in length and had a 5.0mm inside diameter. The quantity of CSF containing 200ug of protein in the volume which depended on the protein concentration of CSF, varying up to 0.80ml was included in each sample gel solution. The spacer gel solution of 0.40ml, layered over the separation gel of the usual volume made a better resolution of protein fractions of CSF.
The normal CSF pattern showed 13 to 18 discrete bands. An electrophoretogram of a control CSF and its densitometric tracing are shown in Fig 2A and 1 respectively. The trace was devided into five zones: prealbumin-zone (Pre.-zone), albumin-zone (Alb.-zone), A-zone, B-zone and G-zone. The values of mean and standard deviation of relative concentration of each protein zone in 23 control samples of CSF were as follows; Pre. 10.9±2.7%, Alb.: 40.3±5.8%, A: 13.5±1.6%, B: 19.2±3.9%, G: 16.1±2.6% (Table I).
Under various pathological conditions the protein concentration of CSF fluctuates. So all the samples were grouped into two. In one group the protein concentration of CSF was equal to or lower than 40mg/dl, in other words within normal range, and in the other it was higher than 40mg/dl, namely elevated. The mean values of relative concentrations of protein fractions of CSF in the various neurological diseases are summarized in Table III. Statistical tests of significance were applied to them (p<0.05), and the following significant results were obtained, as given in Table IV.
For all the diseases of infectious meningitis, neurosyphilis, cerebral infarction, brain tumors, multiple sclerosis and intervertebral disk protrusion, when the protein concentration of CSF was greater than 40mg/dl, the value of relative concentration of the Pre.-zone decreased and that of the G-zone increased. In case of intervertebral disk protrusion the A-zone always elevated, and the Alb.-zone reduced when the total protein was normal. With respect to cerebral infarction, even though the protein concentration was within normal limits the A-zone enhanced and the Pre.-zone lowered. In spite of the normal protein concentration of CSF did the G-zone increase in the diseases of multiple sclerosis, brain tumors and intervertebral disk protrusion. The relationship of the G-zone to immunoglobulins has been briefly discussed.