A comparative population study on SLE from 1956-1 965 revealed higher attack rates in New York City than in Jefferson County, Ala. The difference was attributed to more complete case-finding in New York rather than to regional differences in predisposing factors. In both localities, incidence, prevalence and mortality rates were approximately three times higher for Negro females than for whites. In males, however, few cases were observed, and ethnic differences were considered equivocal.This report describes the results of a comparative epidemiologic study on systemic lupus erythematosus (SLE) in New York City and Jefferson County, Ala, from 1956Ala, from -1965. The data obtained relate to incidence, prevalence and mortality trends, and to ethnic and geographic factors in the

The observation that the relative viscosity of synovial fluid obtained from patients with joint effusion associated with connective tissue diseases is decreased has stimulated a number of investigations directed towards the characterization of the nature of this alteration. Since the relative viscosity of synovial fluid is a function both of the concentration ofhyaluronic acid and ofits degree ofpolymerization elucidation of this problem is predicated on the determination of both of these parameters. Earlier studies have dealt primarily with the differences in hyaluronic acid concentration (Decker, McGuckin, McKenzie, and Slocumb, 1959), or with the comparison of relative viscosities at an arbitrarily chosen concentration (Fletcher, Jacobs, and Markham, 1955). These results indicated that the hyaluronic acid concentration is decreased and suggested that the polysaccharide was depolymerized in synovial fluids obtained from patients with rheumatic diseases.Sundblad (1953) later demonstrated the usefulness of intrinsic viscosity determinations as a measure of the degree of polymerization of hyaluronic acid in human synovial fluid. He calculated the hyaluronic acid concentration of synovial fluid from the glucosamine concentration, which was determined by a modification of the Elson-Morgan procedure, after hyaluronidase digestion followed by trichloroacetic acid precipitation of the proteins. The intrinsic viscosity was calculated from the results of a series of relative viscosity determinations made at different dilutions of the fluid in a phosphate buffer, at pH 7 0, ionic strength 0-20 (OsO8 phosphate + 0-12 sodium chloride), and a temperature of 370 C. Balazs and Sundblad (1959) have shown that the presence of serum proteins does not appreciably influence the viscous behaviour of hyaluronic acid.