The least-squares method is frequently used to calculate the slope and intercept of the best line through a set of data points. However, least-squares regression slopes and intercepts may be incorrect if the underlying assumptions of the least-squares model are not met. Two factors in particular that may result in incorrect least-squares regression coefficients are: (a) imprecision in the measurement of the independent (x-axis) variable and (b) inclusion of outliers in the data analysis. We compared the methods of Deming, Mandel, and Bartlett in estimating the known slope of a regression line when the independent variable is measured with imprecision, and found the method of Deming to be the most useful. Significant error in the least-squares slope estimation occurs when the ratio of the standard deviation of measurement of a single x value to the standard deviation of the x-data set exceeds 0.2. Errors in the least-squares coefficients attributable to outliers can be avoided by eliminating data points whose vertical distance from the regression line exceed four times the standard error the estimate.

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The bone marrow in patients with anorexia nervosa is commonly hypoplastic with transformation of marrow fat. The normal fat cells which appear clear and open in the marrow are surrounded by an amorphous, gelatinous material, thought to represent an increase in the ordinary acid mucopolysaccharide ground substance of the bone marrow. Since this lesion has a similar appearance grossly and microscopically to the lesion of serous fat atrophy found in cachectic patients, we have compared the histochemical properties of this amorphous material in a bone marrow from a patient with anorexia nervosa and from cachectic patients with epicardial serous fat atrophy and with the background substance in hypoplastic marrows. Both this fat-associated deposition in the bone marrow and serous fat atrophy were found to be predominantly a hyaluronic acid mucopolysaccharide. In contrast, the background substance contained a less acid mucopolysaccharide. The increase in bone marrow acid mucopolysaccharide in anorexia nervosa may represent a serous fat atrophy change rather than an increase in ground substance.

Chimeric anti-CD4 monoclonal antibody was administered intravenously as a single dose to eight patients with mycosis fungoides. The dose was escalated throughout the study between patients groups, and individual patients received 50, 100, or 200 mg per dose. Seven of eight patients responded to treatment with an average freedom from progression of 25 weeks (range, 6 to 52 weeks). The treatment was well tolerated, and there was no clinical evidence of immunosuppression. Following treatment, there was significant suppression of peripheral blood CD4 counts in all patients for 1 to 22+ weeks. Only one patient made a very low titer human antichimeric antibody response. All but two patients made primary antibody and T-cell proliferative responses to a foreign antigen administered 24 hours after antibody infusion. However, there was generally marked, but temporary suppression of T-cell proliferative responses in vitro to phytohemagglutinin (PHA), tetanus toxoid, and normal donor lymphocytes. We conclude that at the dose levels studied, this antibody (1) had clinical efficacy against mycosis fungoides; (2) was well tolerated; (3) had a low level of immunogenicity; (4) decreased T-cell proliferative responses in vitro, and (5) did not induce tolerance to a foreign antigen.