Abstract
In testing a hypothesis regarding insulin it was observed that certain human sera specifically fixed complement in the presence of the regular insulin as supplied to patient, in U80 strength; as well as pork, beef, and crystalline insulin.∗
To determine the optimal amount of insulin to be used in the test a titration was set up according to the method of Boerner and Lukens 1 following that of Hooker 2 for the Wassermann antigen, using a serum which had previously shown marked fixation of complement with insulin. The result (Table I) is similar to that found when the Wassermann antigen is titrated. With too large or too small an amount of either antigen or serum the maximal fixation is not obtained.
When this optimal dose of insulin had been determined human sera were tested, in the following quantities—0.1, 0.05, 0.025, 0.0125, and 0.0063 cc; the usual controls were employed. Sera that gave complete or almost complete inhibition of hemolysis in one or more tubes were considered to be positive. A few sera were found in which there was a slight but definite inhibition of hemolysis, recorded as a doubtful reaction. Tests were repeated on the original serum and from 1 to 8 times on sera collected at intervals of from 1 week to 2 months. In all except 5 persons these reactions showed results similar to those found in the first test. The variations were of the same order as are commonly found when the Wassermann test is repeated on a given serum. The results are shown in Table II.
The normals in this table consisted of doctors, nurses, and members of the laboratory staff. They were apparently in good health but had not all had physical examinations. All were free from clinical signs of syphilis and 42 had negative blood-Wassermann reactions.
The thyroid-patients had been selected at random from the Thyroid Clinic and varied both in clinical condition and in the height of the basal metabolic rate.
The stage of pregnancy varied from the 3d to the 8th month and appeared to show no correlation with the reaction.
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