Kurt Altman

Tryptophan Pyrrolase Induced in Human Liver by Hydrocortisone: Effect on Excretion of Kynurenine

Administration of hydrocortisone causes two- to fourfold increase in the level of activity of tryptophan pyrrolase in human liver, as measured in needle-biopsy specimens. Correlation of the higher levels of the enzyme with the amounts of urinary kynurenine suggests that the tryptophan pyrrolase level, which is regulated by adrenocortical hormones, may be the important variable in the increased excretion of tryptophan metabolites that accompanies various diseases.

SUPPRESSION OF THE PRIMARY IMMUNE RESPONSE INDUCED BY D-L PENICILLAMINE.

Summary Rabbits treated with D-L peni-cillamine beginning one day prior to intravenous injection of I131 labeled human serum albumin showed suppression of the immune response. Two-thirds of the animals completely failed to undergo immune elimination of the antigen and to form circulating antibody. The remaining ⅓ of the animals in which immunity did occur exhibited retardation of the onset of antibody synthesis. This observation contrasts with an earlier study in which the drug, if administered for 28 days before sensitization, resulted in accelerated onset of immune responsiveness.

ACCELERATED IMMUNE RESPONSE INDUCED BY D-L PENICILLAMINE.

Summary Rabbits treated with D-L penicillamine for 28 days prior to intravenous injection of I131 labeled human serum albumin showed accelerated elimination of the antigen and correspondingly earlier appearance of free antibody, as compared with control animals. Graphic analysis of the radioactive clearance data indicates that the length of the induction period preceding antibody synthesis was shortened. Once immunity commenced, the slopes of the disappearance curves of both experimental and control group were parallel, suggesting no change in the rate of antibody production.

Nuclear imaging and the assessment of human Fc receptor function: Studies in systemic lupus erythematosus

In vivo immune clearance of immunoglobulin G sensitized autologous erythrocytes (rbc) was studied in nine patients who fulfilled American Rheumatism Association (ARA) criteria for systemic lupus erythematosus (SLE). Opsonized rbc were radiolabelled with technetium 99. The rate of radioactive blood clearance was measured, as was organ-specific radioactive uptake utilizing area-of-interest (AOI) measurements in a computerized scintigraphic imaging system. It was shown that dynamic quantitation of an AOI corresponding to the heart generated time-activity curves which approximated blood-clearance curves. Calculation of first order clearance (min per 50% decrease in counts) showed a highly significant correlation between rates derived from heart AOI curves and those derived from blood-clearance curves (r = 0.9483, P = 0.0003). Clearance curves showed a monoexponential slope in most patients. Further exploration of organ-specific AOI curves showed that percent splenic uptake and the nature of the splenic uptake curves varied between patients. These studies point toward a variable splenic role in Fc receptor function for SLE patients and further demonstrate the utility of nuclear imaging in studying immune clearance.