Microscopic Reading Research Articles

The Nickerson-Kveim reaction in sarcoidosis

The Nickerson-Kveim cutaneous test for sarcoidosis, as employed in our studies, consisted of the intradermal injection of a heat-sterilized suspension of human sarcoid tissue and subsequent histologic examination of the site of injection. In a positive reaction a sarcoid-like granuloma is produced at the injection site after some weeks. The test was given to 200 patients. Fifty-eight patients had sarcoidosis, the diagnosis being confirmed by biopsy of an involved organ or tissue. Eighty were sarcoidosis suspects; of these, thirty-three were strong suspects. Fifty-four patients had diseases other than sarcoidosis, and they served as “controls.” Eight patients had unclassified granulomatous disorders. Results of this study disclose that a high percentage of the biopsy-confirmed group and of the group containing strong suspects gave histologically positive responses to the test—86 per cent of the former and 85 per cent of the latter. Two patients in the “control” group had positive responses to the test, an incidence of 4 per cent of false positive reactions. Biopsy of the injection site was considered an obligatory part of the intracutaneous test in this study. The biopsies were usually carried out four to six weeks after the sarcoid suspensions were injected. In all, 571 biopsies of Nickerson-Kveim test areas were performed. In this study a Nickerson-Kveim result was called positive only if a histologically characteristic sarcoid-like granuloma could be demonstrated at the site of injection after a suitable interval. Foreign body reactions and non-specific reactions sometimes interfered with the microscopic reading of the test. Suspensions of normal lymph node and normal spleen did not evoke a positive reaction in patients with sarcoidosis who did respond to a suspension of sarcoid tissue. The Nickerson-Kveim intracutaneous test is a useful confirmatory tool in the diagnosis of sarcoidosis. The test is of aid especially when tissues from involved organs are not readily accessible to biopsy. The test has growing applicability in differentiating granulomatous conditions. In such instances the result of the Nickerson-Kveim reaction can also be a determining factor in the choice of proper therapy.

A Small Chemical Separation of the Chlorine Isotopes

A SMALL chemical separation of the chlorine isotopes has been observed by heating carbon tetra-chloride with sodium amalgam, when the reactionoccurs almost quantitatively1 and the light isotope reacts preferentially. Carbon tetrachloride (A.R.) was fractionated eight times (twenty-four fractions) and the densities of the middle fractions after drying with purified phosphorus pentoxide were compared by the flotation method, using a cylindrical pyrex float. After four successive fractions the density became constant. The float was controlled by means of a small piece of enclosed soft iron. The ground-stoppered vessel containing the carbon tetrachloride was placed in an outer vessel containing phosphorus pentoxide and supported by brass clamps in a thermostat at 23°. An intermittent Gouy regulator2 controlled the temperature, which was read on a Beckmann thermometer by a travelling microscope reading to 0.002 mm., so that 0.00025° could be easily read. The thermometer varied 0.00019° per mm. with change of pressure. The velocity of the float varied linearly with temperature, 0.001° in set point corresponding with a density change of 1.9 × 106 and a velocity change of 0.0024 cm. per sec.

Societies and Academies

LONDON. Physical Society.—Meeting held in University College, March 22.—Prof. S. P. Thompson, president, in the chair.—A paper on the expansion of silica was read by Prof. Callendar. The extreme smallness of the thermal expansion of silica (fused quartz) renders the determination of its coefficient of expansion more difficult than is the case with many substances. The author has made experiments upon a rod of pure silica 40 cms. long and 1 mm. diameter. This rod was enclosed in a platinum tube about 3 mms. diameter, which could be raised to various temperatures by the passage of a suitable electric current. Both the rod and the tube were firmly fixed at one end, and the positions of the other ends were accurately observed by a micrometer microscope reading to a thousandth of a mm. The expansion of the tube, in conjunction with a knowledge of its coefficient of expansion, served as a means of determining the temperature of the tube, and, therefore, of the rod. The increase in length, the original length and the range of temperature of the silica being known, the coefficient of expansion can be at once calculated. In some previous experiments the author has investigated the distribution of temperature along a heated platinum rod subjected to cooling at the ends. These experiments prove that the error due to end effect, in the case of the silica rod, can be neglected. The expansion of silica up to 1000° C. is regular, and is about one-seventeenth that of platinum. Between 1000° C. and 1400° C. silica expands more quickly than below 10000 C., and if left at any temperature for a considerable time continues to slowly increase in length. If a curve be plotted having temperatures as abscissae, and increases in length as ordinates, a straight line will represent the expansion of silica up to 1000° C. Above 1000° C. the curve bends upwards, and upon cooling it returns along a path above the ascending curve, so that the final length of the bar is greater than the original length when the lower temperature is reached. The determination of the coefficient of expansion at these high temperatures was made by means of a variable zero, that is by using for the length of the rod that obtained by suddenly cooling from the higher to the lower temperature. At 1400° C. the properties of silica alter and the expansion is replaced by a contraction. On cooling from above 1400° C. to ordinary temperatures there is first an expansion and then a contraction. This property was illustrated by Prof. Callendar, the small changes in length of the rod being magnified by a lever and shown upon a screen by an optical arrangement. The critical point at which contraction occurs on heating has been found by Le Chetalier at about 8oo° C. His experiments were made by a differential methcf, using porcelain as a standard substance. As the expansion of porcelain is uncertain, the author thinks it probable that the effect noticed may be due to irregularities in the expansion of porcelain rather than in that of silica. Mr. Boys expressed his interest in the experiments and asked if the small coefficient of expansion of slate had ever been measured. The small expansion of silica would make it a useful suspension for pendulums on account ot the small compensation necessary. Its perfect elastic properties might be made use of in hair springs for chronometers. Prof. Threlfall said that he had tried to measure the expansion of silica between 0° C. and 70° C. by weighing rods in distilled water, but the method was not accurate. He had made experiments similar in principle to the author's, using temperatures from 0° C. to 100° C. The devitrification of silica is troublesome, and he thought that the rate of devitrification in presence of air increased with the temperature. Dr. Donnan thought that the irregularities in the expansion of silica pointed to a complex composition. Mr. Porter (Eton) asked if the effect ot fused quartz on polarised light had been investigated, and if this effect altered after heating to 1400° C. Mr. Boys said that quartz rods formed by fusion depolarised light. The chairman said that he had noticed the effect spoken of by Mr. Boys, due to strain, but he had been unable to detect any rotatory power. Prof. Callendar, in reply to Mr. Lupton, said that the expansion of quartz crystals was much larger than that of fused silica.—The spectroscopic apparatus of University College was then exhibited by Dr. Bily.—The Society then adjourned until April 26.