Quantitative Determination Of Proteins Research Articles

SPINAL FLUID IN SYPHILIS

It is generally conceded that for serologic diagnosis of syphilis and for guidance in therapy, two or more procedures should be used, including a complement-fixation test of proved sensitivity and reliability. Our object in this paper is to compare the results of the complement-fixation and the microscopic slide precipitation tests 1 in identical samples of spinal fluid, and to correlate these findings with the clinical data and also with the quantitative total protein and globulin determinations by the method of Exton and Rose. 2 Since discrepancies between tests as reported by most authors are mainly in the tests in patients undergoing treatment, we grouped our cases according to clinical diagnosis, with notations as to whether or not treatment had been instituted before coming under observation. MATERIAL STUDIED AND METHOD OF PROCEDURE The patients studied were from the department of dermatology and syphilology of the Lenox Hill Hospital

Quantitative estimation of total protein in cerebrospinal fluid

Abstract 1.1. It is felt that quantitative protein determinations on cerebrospinal fluids should be carried out routinely as an aid to diagnosis. 2.2. A rapid, simple, volumetric method for the quantitative determination of the total protein content of cerebrospinal fluid is described. 3.3. The principle is the precipitation of protein by Tsuchiya's reagent, centrifugalization in a finely calibrated centrifuge tube and comparison with a similarly treated standard protein solution. 4.4. The total protein in 23 normal lumbar fluids varied from 17 to 40 mg. per cent with an average of 29. 5.5. A table containing the total protein determinations of 359 selected cases is presented. 6.6. Total protein values of different observers in various pathologic conditions are tabulated.

COLLOIDAL GOLD

While there is considerable disagreement between investigators as to the exact value of the various observations with Lange's colloidal gold test for cerebrospinal fluid,1all are unanimous in their opinion regarding its value as a useful confirmatory test in the diagnosis and the differentiation of syphilitic and nonsyphilitic diseases of the central nervous system. The test is based on the observations of Zsigmondy2that proteins will protect various colloidal substances from being precipitated by electrolytes. The degree of protection has been found to be specific for each protein, and is expressed in terms of milligrams of the protein that is capable of protecting 5 cc. of colloidal gold against 0.5 cc. of a 10 per cent solution of sodium chloride. It has been known for a long time that the protein content in spinal fluid varies in pathologic conditions of the central nervous system. Accordingly, Lange took advantage of Zsigmondy's observations and endeavored to apply them to the quantitative determination of protein in the spinal fluid; however, contrary to his expectation, he found that an excess of protein precipitated colloidal gold instead of protecting it.

STUDIES OF THE BLOOD IN BERIBERI

<h3>I. REFRACTOMETRIC INVESTIGATION OF THE SERUM</h3> Refractometric investigation of the blood was carried out for the first time by Strubell¹in 1900. He considered the procedure available for measuring the osmotic pressure of the blood, but Reiss,²after two years' thorough study of the subject (1901-1902), found that the refractive index bears no relation to osmotic pressure, but that refractometric estimation is practically equivalent to a quantitative determination of protein in the blood. To prove that such a relation exists, Reiss cited a table of results of Vaucher,³in which he compared the figures obtained by refraction with those obtained by weighing the proteins. According to Reiss, the quantity of nonprotein substances in the blood shows no remarkable variation, although the contrary is generally believed to be true. The freezing point of the blood, for example, is normally 0.56 C., and even in extreme cases it does not fall below