Gold Sol Reaction

Gold Sol Reaction (Goldsol; G.S.R.), or reaction with colloidal gold, is the change of an artificial colloidal gold solution by the action of cerebrospinal fluid on it. The color of the colloidal gold solution (purple-red, violet, blue, light blue, white) depends on the degree of dispersion of the colloidal particles; the coarser the particles, the more the colloidal gold solution, passing through the entire spectrum of colors from purple-red, approaches complete decolorization (complete coagulation). The G.R. was proposed by Lange in 1912 and since then has found wide application in the study of cerebrospinal fluid for the differential diagnosis of organic nervous diseases. -Technique of the reaction (according to Lange): to 1 liter of distilled water is added 10 cubic cm of a 2% solution of gold chloride and 10 cubic cm of a 2% solution of potash, the mixture is heated to boiling, after which 10 cubic cm of a 1-percent solution of formalin is added to it in portions, constantly shaking the mixture. When the experiment is set up correctly, the liquid takes on a saturated purple-red color. Before setting up the main experiment, preliminary titration of the colloidal solution (determination of salt sensitivity) is performed: into test tubes with 1 cubic cm of NaCl (dilutions from 0.1% to 0.7%) is added 5 cubic cm of the gold solution; the test tubes are left standing at room temperature; the results of the change in the solution are determined after 3 hours, and the highest dilution of salt that still does not cause a change in the color of the colloidal gold is taken. Main experiment. The entire reaction takes place in 16 test tubes (preferably of Neva glass, as is all other apparatus). Into the first test tube is poured 1.8 of the NaCl solution of established concentration (more often 0.4%) and 0.2 of cerebrospinal fluid, it is mixed, and 1 cubic cm is transferred to the next test tube, into which, as into all the others (and into the control), is poured 1 cubic cm of the salt solution. From the 2nd test tube, after mixing, 1 cubic cm of the solution is transferred to the 3rd and so on. From the 15th test tube, 1 cubic cm of the mixture is removed entirely. Then into the test tubes (and into the control) is added by 5 cubic cm of the colloidal gold solution; the results are determined after 24 hours. The cerebrospinal fluid taken for the reaction should be clear and free from significant blood impurities; fluid that has stood for a long time and is turbid is not suitable for the reaction. The results are recorded in the form of a curve (see Figure 1). The ordinate shows the degree of coloring of the solution; the abscissa represents dilutions from 1:10 to 1:320,000. -From the various forms of curves, several types have been established, which are now accepted as characterizing the degree of reaction, and not of this or that disease. 1. Normal curve-absence of change in color in all test tubes or insignificant changes in two or three test tubes. 2. Syphilitic curve (Lueszacke)-change from the 2nd-3rd test tube, maximum at the 3rd-5th test tube (up to a red-violet color). 3. Curve of lues cerebri: changes from the 2nd-3rd test tube, maximum 3rd-5th test tube (from violet to light blue). 4. Tabetic curve-intermediate between the previous tabetic and the next paralytic. 5. Paralytic curve-complete decolorization of the solution in the first 5-7 test tubes, then a rise of the curve. 6. Meningitic curve-changes from the 2nd-3rd test tube, maximum 5th-7th test tube (from violet to light).-

From the described forms, deviations (atypical forms) are encountered, which are determined by a weaker depth of the curve, the presence of a tooth (blood impurity), extending for one or two test tubes, an expansion of the maximum color change, the presence of terraces and combinations of different types (see Figures 1, 2 and 3). The registration of changes in the colloidal gold solution in the test tubes, besides curves, can be expressed in numbers; if we take red as 0, then red-violet as 1, etc., light as 6 (example- red red-violet- / \ \ a \ \ a Figure Paralysis progressiva: a-before treatment; b-after treatment. paralytic curve: 6666665432100...). The type of curve under the influence of endolumbar treatment with Neosalvarsan can change; e.g., a paralytic curve can turn into an abortive paralytic, etc. (see Figure 4). On the basis of clinical study of the G. reaction, the following evaluation can be made. 1) The G.R. in cerebrospinal fluid is not a specific reaction for syphilis. 2) It is connected with patho-anatomical changes in the central nervous system, regardless of etiology and the nature of the process that caused these changes (inflammatory, degenerative). 3) It is not possible to establish the type of curve for one or another form of organic lesion of the nervous system, although one can note a tendency for the predominant appearance of paralytic, tabetic, and cerebral syphilis curves in corresponding diseases. 4) The essence of the reaction is insufficiently studied; it owes its origin to biochemical changes in the central nervous system; the unity of the curves indicates the unity of changes in various disease forms.